Smartphone Apps for the Smart Cryonicist

26. September 2011 · Comments Off · Categories: Cryonics, Health · Tags: , , , ,

As every modern consumer knows, smartphones are today’s go-to portable technology. Everything from GPS navigation to finding a good deal on your next meal or haircut right NOW to a wide variety of games and applications may be had at the touch of a button. But developers of smartphone applications (i.e, “apps”) are only just beginning to realize the true capabilities of having so much computing power in the palm of your hand. Indeed, the possibilities for health monitoring applications in combination with GPS location bodes well for cryonicists.

Until cryonics-specific apps become available, there are several existing applications useful to cryonics members and organizations. Here are some of the most interesting from the Android Market:

ICE (In Case of Emergency):   Emergency personnel look for ICE information in patient mobile phones. This ICE app has a couple of widget options and can be accessed even when the phone is locked. My favorite feature is the ability to put any special instructions (like the protocol from your Alcor bracelet) on the main screen. The app acts primarily as an emergency contact list. Your cryonics service provider should be #1, followed by family and friends who support your cryonics arrangements. Additionally, you may enter your vital stats, medical and dental insurance information, and any known allergies, conditions, and/or medications.

For those with “dumb phones,” just create a contact called “ICE” and enter your cryonics organization’s emergency number. Additional information about placing ICE  numbers in your cell phone may be found in this article by Fred and Linda Chamberlain.

Emergency Button: Emergency Button sends a distress signal with your coordinates to a defined recipient when pressed. This has obvious utility for all matters of personal safety, and can be used to alert your cryonics organization to emergency health situations as soon as they emerge.

Google Latitude: Latitude is a GPS location tracking app. It allows for various privacy settings and can be configured to share only with specific people. A cryonics organization could, with its members’ permission, use such an app for real-time location tracking.

These are just three basic apps that are commonly available and useful to cryonicists now. I hope to be updating this list as improvements in smartphone technology continue.

Interview with Alcor member David Croft

11. May 2009 · Comments Off · Categories: Cryonics, Society · Tags: , , , ,

david_croftDavid Wallace Croft is an Alcor member in the Dallas area where he lives with his wife Shannon and five children, Ada, Ben, Tom, Abe, and Ted.  He is employed as a Java software developer and is a part-time doctoral student.  His contact information and his weblog are available at www.CroftPress.com.

1. How did you first learn about cryonics?

I first learned about cryonics from the Extropians.  I think I first learned of the Extropians from “Wired” magazine.  I really liked what I read in the Extropian Principles so I dug into this subculture online.  I was a volunteer Webmaster for the Extropy Institute for a brief period.

2. When did you join Alcor and what motivated you to become a member?

Along with every other techie, I was swept into the Silicon Valley dot com boom during the late 90′s.  I worked next to Xerox PARC so I would sometimes wander over to attend their guest lectures including a slideshow on the subject of cryonics presented by Dr. Ralph Merkle.  I had a chance to attend local cryonaut dinners and meetings including a meeting at the Shaw-Merkle residence.  Actually signing up remained on my to-do list for a few years until I saw an ad on the back of the shirt of insurance agent Mr. Rudi Hoffman at an Extropian conference.  I approached him and he helped me make it happen.

3. How does your membership impact your life plans or lifestyle?

My Alcor membership has given me some peace of mind with regard to the terror of impending death.  I lost my faith in the supernatural afterlife at an early age and I struggled with the ramifications.  Now that I am middle-aged with five children, death is less frightening but I still think about my dwindling days with some despair.  My cryonics hope keeps me functional.

I am currently in Dallas but my long-term plan is to find a job in Phoenix, possibly in academia, so that I can establish my retirement residence near Alcor.

4. What do you consider the most challenging aspect(s) of cryonics?

Even amongst my atheist allies, cryonics is considered crazy.  When I read Humanist literature, I see a “mortalist” attitude where an acceptance of death is considered the rational alternative to belief in a supernatural afterlife.

5. Have you met any other Alcor members?

I have enjoyed my fellowship with members over the years, most recently at the Alcor conferences.  Awhile back, we had a cryonauts dinner here in the Dallas area with Dr. Scott Badger, Chana de Wolf, and Todd Huffman; I note that all four of us are involved in the study of the mind and brain.  I had the opportunity to attend one of the annual get-togethers hosted by Max and Natasha More in nearby Austin.  I also sample the CryoNet, Society for Universal Immortalism, and Venturists electronic mailing lists.

6. What areas of Alcor’s program would you like to see developed over the next 5-10 years?

I would like to see more Alcor conferences.  I would also like to see Alcor establish a second operational center in another location.

7. What kind of lasting contribution would you like to make to cryonics?

I would like to help establish a democratic religion for cryonaut brights.  I was inspired by the 1933 “Humanist Manifesto” proposing Humanism as a new religion.  I am the Treasurer and a co-founder of the Society for Universal Immortalism (SfUI), formerly known as the Transhumanist Church, which requires cryonics suspension arrangements before becoming a voting member.  I have also created a website for my own personal micro-religion which I call “Optihumanism”.  In my “Optihumanist Principles”, I have attempted to blend Religious Humanism, Neo-Objectivism, and Immortalism in a concise statement of my beliefs.  Less seriously, I also have a webpage for my “Cryobaptist Church” which makes the tongue in cheek assertion that salvation can be achieved by a post-mortem baptism in liquid Nitrogen.

8. What do your friends and family members think about your cryopreservation arrangements?

In general, my friends and family think it is a bit eccentric.  I am attempting to plant seeds with my wife and children by introducing them to cryonics fiction.

9. What are your hobbies or special interests?

One of my special interests is church-state separation activism.  With the assistance of my Objectivist friend and attorney Dean Cook, my family has legal cases pending challenging the constitutionality of a couple of new laws involving religion in Texas public schools:  a mandatory moment of silence and adding “under God” to the state pledge.

I am also a part-time doctoral student in Cognition and Neuroscience at the University of Texas at Dallas.  Although my Bachelors is in Electrical Engineering, my two Masters degrees had a focus on neuroscience and neuromorphic systems.  As a programmer, I have been hired to work on a number of interesting projects including neural network chip design, intelligent software agents, peer-to-peer frameworks, and multiuser 3D environments.  My academic research could be described as pursuing artificial intelligence via a study of spiking neuronal networks.

10. What would you like to say to other members?

Many of my atheist, humanist, objectivist, and immortalist friends do not have children.  I recommend that you have them if you can.  Children are blessings we give to ourselves.

40,000 year old frozen baby mammoth unearthed

05. May 2009 · Comments Off · Categories: Cryonics, Science · Tags: , , , , , ,

mammoth.jpg

In “Ice Baby” by Tom Mueller, the May 2009 issue of National Geographic announces the recent discovery of a 40,000 year old baby mammoth in Sibera. She is called Lyuba, named after the wife of the Nenet reindeer herder who found her, and is in near-pristine condition, having even her eyelashes. In fact, besides most of her wooly coat being gone, the only pieces missing (part of her tail and right ear) were destroyed after her recovery. Even so, she is undoubtedly the most complete specimen of mammoth to date.

Of course, paleontologists such as Dan Fisher, who has spent his entire life studying Pleistocene mammoths and mastodons, are excited by this find because Lyuba provides the most complete set of data it is possible to obtain, and all from one animal. Before, Fisher and his colleagues had been forced to infer certain states of health from fossils (primarily teeth) by comparing against similar findings in the mammoth’s closest relative, the elephant. But Lyuba was so well-preserved that Fisher was able to scan her, take tissue samples, and even retrieve stomach contents.

A three-day autopsy, during which Lyuba was allowed to partially thaw to facilitate more invasive procedures, indicated that Lyuba was a well-fed one-month old mammoth at the time of her death, indicating that death was accidental. Supporting these findings was a dense mix of clay and sand in her mouth and throat, which she likely inhaled after falling into riverbank mud, leading to suffocation, but also the probable cause of her excellent preservation. Dense mud would have sealed out oxygen and prevented aerobic microbes from decomposing her soft tissue, and then lactic acid-producing microbes colonized her tissues, effectively “pickling” her carcass. Later, the ground turned to permafrost, freezing her as well.

Following Lyuba’s article in National Geographic is another article entitled “Recipe for a Resurrection” (also by Tom Mueller), which discusses the possibilities for cloning extinct species such as mammoths and Tasmanian tigers. Pointing to the recent success of Teruhiko Wakayama’s team in cloning mice that had been frozen for 16 years, and the recent publishing of 70 percent of the mammoth genome by a team led by Webb Miller and Stephan C. Schuster, the article details the hurdles that still remain in accomplishing this long hoped-for feat.

Oddly enough, though cloning offers no hope of bringing back the same individual organism, the article ends with a  pro-death quote from Tom Gilbert, “an expert in ancient DNA at Copenhagen University who with Schuster and Webb pioneered the harvesting of mammoth DNA from hair,” who “questions both the utility and wisdom of cloning extinct species. –  ‘If you can do a mammoth, you can do anything else that’s dead, including your grandmother. But in a world in global warming and with limited resources for research, do you really want to bring back your dead grandmother?’”

The Field Museum in Chicago is planning an exhibition tour starring Lyuba in 2010, with assistance from the National Geographic Society.

Watch Waking the Baby Mammoth on National Geographic throughout the month of May (next airing May 6).

A simple method to resuscitate rats from cold circulatory arrest

12. January 2009 · Comments Off · Categories: Death, Health, Neuroscience, Science · Tags: , , , , ,

This is the eighth entry in a series about resuscitation of non-hibernating rodents from circulatory arrest at ultraprofound hypothermic and high subzero temperatures. In 1982, P.D. Rogers and G.P. Webb published some of their observations (based on previous papers and a Ph.D thesis) after carrying out a classroom demonstration of suspended animation in which they cooled rats and then resuscitated them after 30 minutes at 0 degrees C. The demonstration was performed as a means to stimulate discussion among students regarding the characteristics and diagnosis of death, the effects of hypoxia during cooling, and the limitations of ECG measurements.

Because the “Giaja method” of cooling employed by Andjus and Smith induced hypoxia and hypercapnia, the authors were interested in comparing resuscitation rates in hypoxic vs. non-hypoxic animals. They did so by anesthetizing rats and immersing them (except for limbs, tail, and head) in crushed ice and water to induce ultra-profound hypothermia, as measured by rectal temperatures. During the cooling process, some animals were artificially ventilated until cardiac arrest (respired rats), while others were not (unrespired rats). After 30 minutes of cardiac arrest at temperatures near 0 degrees C, all rats were ventilated during rewarming in a 40 degree C water bath until heartbeat returned and reached 60 beats/min, at which point they were removed from the bath and warming was continued under a 100 W lamp. ECG was recorded throughout.

Rogers found that approximately 90% of respired rats began breathing spontaneously during rewarming and 100% regained heartbeat. On the other hand, less than 10% of unrespired rats recovered spontaneous respiration during rewarming, and when the heart did restart (it often did not), heartbeats were erratic and did not circulate blood due to severe vasodilation assumed to be caused by the combination of hypoxia and hypothermia. Rogers found that he was able to resuscitate 70-90% of unrespired rats by means of abdominal compression (i.e., “abdominal pumping”), but even this method was only successful when the heart restarted.

Though it is easy to assume that hypoxia is the cause of more difficult and less successful resuscitation of unrespired vs. respired rats, Rogers and Webb point out that respired rats may simply be benefiting from the protective effects of hypocapnia on pH changes during hypothermia. They discuss at length the question of “what is the optimal pH in the hypothermic animal,” which remains unanswered.

An interesting phenomenon known as “heart block” was also demonstrated by these experiments. ECG recordings obtained from unrespired rats often showed a QRS complex during rewarming, which most people would assume to indicate that the heart had restarted. However, because ECG is simply a record of electrical activity, this is not always the case:

The observation that a QRS complex occurs in the absence of cardiac output illustrates the limitations of ECG measurements. The ECG is a record of electrical activity within the heart, and any conclusions about mechanical events are extrapolation, though usually with sound theoretical and empirical foundation. In fact, when the chest cavity is opened in unrespired animals with temporarily restarted hearts, it is possible to record QRS complexes in the absence of any apparent heartbeat, i.e., dissociation between excitation and contraction.

Suggestions for further hypothermia experiments in rats include measuring blood pressure during cooling and rewarming, removing blood samples for pH and gas analysis during the experiment, and monitoring electroencephalogram (EEG). Having discovered in previous experiments that unrespired rats suffered from a  collapse in blood pressure during cooling prior to cardiac arrest, while cardiac arrest and blood pressure collapse occurred simultaneously in respired rats, Rogers also wonders whether this pre-arrest collapse can be prevented with vasoactive medications and whether this would improve resuscitation rates in unrespired rats. Answering questions such as these would have far-reaching implications in the treatment of accidental hypothermia in humans.

The method that was used by Rogers et al. to resuscitate rats from ultra-profound hypothermia appears superior in terms of animal welfare and equipments needs. Because hypothermia is not induced by methods that induce hypoxia (as in the experiments of Andjus and Smith), the need for specific warming protocols are greatly lessened.  The use of anesthetics and ventilation during cooling allows the researcher to exclusively focus on the mechanisms of cold circulatory arrest and investigate methods (such as administrations of medications or complete blood substitution) to prolong the period rats can tolerate ultra-profound circulatory arrest and even subzero temperatures.

Resusciation of larger mammals from subzero temperatures

08. January 2009 · Comments Off · Categories: Death, Science · Tags: , , , ,

This is the seventh entry in a series about resuscitation of non-hibernating rodents from circulatory arrest at ultraprofound hypothermic and high subzero temperatures. After spending a few years on perfecting on Andjus’ technique for resuscitating rodents (rats and hamsters) from ultraprofound hypothermic and high subzero temperatures, Audrey Smith upped the ante and attempted the same feat in larger mammals. In her 1957 publication, “Problems in the resuscitation of mammals from body temperatures below 0 degrees C,” she detailed the results of such experiments performed on Dutch rabbits and small primates of the species Galago crassicaudatus agisymbanus.

Smith used a modified version of the closed vessel technique to anesthetize and initiate cooling in the rabbits, then placed them in ice water for further cooling. Respiration ceased between 13 and 21 degrees C and the heart stopped beating a couple of minutes later when temperatures were 3 or 4 degrees lower, at which point the rabbits were immersed in -5 degrees C baths. Due to larger body mass, it took much longer for deep body temperature in rabbits to drop from 15 to 10 degrees C than it had in hamsters, though the rabbits’ extremities froze quickly. Smith wished to avoid this discrepancy, so she attempted to speed cooling by injecting a cold, creamy saline and serum mixture into the stomach and rectum. Cooling was certainly faster, but unfortunately the gastric mucous membrane was damaged and sometimes the stomach ruptured, forcing her to abandon this method. Further investigation finally led her to determine that thoroughly wetting the undercoat to remove all insulating air from the fur and vigorously stirring the -5 degree bath led to a a fall in deep body temperature to the freezing point of plasma within 20 to 40 minutes of extremities freezing. Galagos were cooled similarly. Their extremities had been freezing for around 40 minutes by the time internal organs began to freeze.

James Lovelock built a larger microwave diathermy apparatus for Smith’s rabbit and primate experiments on the assumption that larger body masses simply needed more magnetronic power. Initial warming attempts resulted in severe superficial burns before the rest of the animal had been thawed. Compensating for this effect resulted in the next few animals’ visceras being cooked. Finally, a technique was determined for warming from -0.6 degrees to 10 or 15 degrees C within a minute.

Fifteen rabbits and two galagos underwent this treatment and resumed heartbeat and pink mucous membrane coloring when temperature reached around 15 degrees C. Between 20 and 30 degrees C they began breathing and diathermy and artificial respiration was stopped while gentle warming was continued under a heat lamp or in an incubator, while a few rabbits were left at room temperature. Smith describes the results:

Muscle tone improved and the animals made spontanous movements. Some of them, including the two galagos, sat up and moved around. Within about an hour, however, the reanimated rabbits and galagos all collapsed and died. At post mortem the only obvious lesion was a severe haemorrhage in the upper part of the stomach.  This is the part of the stomach which secretes hydrochloric acid.

Smith had noticed similar lesions in the stomachs of hamsters she had frozen which had died shortly after resuscitation, also from the acid-secreting portion of the stomach. She theorized that lowering body temperature disabled the function of mucous-secreting cells (which protect the stomach from acid) by increasing their permeability to hydrochloric acid and causing the acid in the stomach to diffuse and injure blood vessels. Smith tested this theory by neutralizing stomach acid with sodium bicarbonate during cooling but before freezing. This time, after resuscitation, there was no sign of gastric hemorrhage. Sadly, the rabbits undergoing this treatment still did not live more than 4 hours, and two galagos which seemed to make an excellent recovery died within 24 hours. Though their stomachs were normal, these animals were found to suffer from pulmonary edema and one had bloody fluid in the duodenum and jejunum.

Other topics investigated and reported within her manuscript were the effects of freezing on the hamster placenta and studies on the isolated heart. Observations made on the placentas of hamsters frozen on the 9th, 10th, and 11th days after fertilization of the egg (when the hamster placenta undergoes rapid growth and freezing disrupts foetal development) indicated that bleeding may also be induced by circulatory disorders. Smith speculated that it may be due to derangement of cardiac muscle tissue itself.

This compelled her to experiment on isolated hamster hearts. Interestingly, although whole hamsters did not survive freezing for 3 hours, isolated hamster hearts resumed beating for several hours when perfused in vitro after freezing for 3 hours. She also found that the isolated rat heart recovered completely after freezing at -2 degrees C for 1 hour, but failed to recover from temperatures below -5 degrees C. Further investigations involving perfusion of hamster hearts with glycerol led to resumed beating of hearts after lowering to -20 degrees C, many of which established a regular beat. These results indicated that the heart may not have been the limiting factor in resuscitating whole animals from subzero temperatures, and that improved methods of cryoprotection might be developed for resuscitation of whole animals from subzero temperatures.

Behavioral effects of ultraprofound hypothermia in rats

04. January 2009 · Comments Off · Categories: Death, Science · Tags: , , , , ,

This is the sixth entry in a series about resuscitation of non-hibernating rodents from circulatory arrest at ultraprofound hypothermic and high subzero temperatures. After successfully reanimating rats from deep body temperatures of 0 – 2 degrees C and subsequent respiratory and cardiac arrest, Andjus allowed the survivors to live for many months afterward in order to observe any long-term effects of hypothermia. What he noticed, beyond temporary weight loss and a couple of rats with impaired temperature regulation, was that animals that had been cooled did not appear to suffer any gross or debilitating effects. Although food intake and sexual behavior were initially diminished, the rats regained healthy appetites within a few days and went on to produce normal offspring within 3 months of cooling.

Andjus, having pioneered a method of resuscitation of rats from ultraprofound hypothermia, also had occasion to take the first look at the effects of hypothermia on learning and memory. In his brief 1955 Nature publication, “Effects of Hypothermia on Behaviour,” Andjus first compared the ability of cooled (0-1 degrees C) vs. untreated (control) rats to learn a serial problem-solving task. Next, he compared two groups of rats cooled to different temperature ranges (0-1 degrees C and 13.4 – 18.5 degrees C) to controls in a classical maze-learning paradigm. Rats were trained on the maze, cooled, tested for retention, and finally trained on a serial problem-solving task.

The results showed a significant impairment in problem-solving ability in rats cooled to 0-1 degrees C compared to controls, but not in rats cooled to 13.4 – 18.5 degrees C. However, the effect was only temporary, as demonstrated by the fact that impairment decreased as the interval between cooling and testing increased. And though memory retention was also affected by hypothermia, Andjus stated that “the differences among experimental and control groups were very small, and in no instance were they statistically significant,” indicating that even severe hypothermia does not produce permanent long-term physical or behavioral changes.

These initial results were supported in another experiment by N. Mrosovsky in 1963, who reported that severe hypothermia did not affect the response of rats to a conditioned avoidance task when cooling was begun only 15 minutes after animals were trained to criterion. In this task, rats were placed in an apparatus with electrified wire flooring such that either side of the cage floor was capable of shocking the animal. To facilitate one-session avoidance learning, the rats were first taught that they could escape from shock by undergoing 20 shock trials at varied time intervals (30, 60, 90, and 120 seconds) in random order. Then they were conditioned to avoid the shock (conditioned response) by responding immediately to a light (conditioned stimulus) that came on inside the dark experimental room 8 seconds before the shock. The light stayed on until the rat crossed the dividing line between the two sides of the apparatus. When they reached the criterion of six successive avoidance responses, experimental animals were returned to their home cages for 15 minutes before cooling was initiated and rewarming was carried out under a bench lamp. Control animals remained in their home cages until retesting.

Both experimental (cooled) and control (untreated) groups were retrained in the avoidance task 13 days after hypothermia. On Day 14, after three successive avoidance responses, training was continued, but the shock came on in the opposite side of the box at the same time as the light (both were on for 8 seconds). The rat was successful in this “reversal procedure” if it stayed on its side of the apparatus while the light was on six consecutive times.

He reported no significant differences in initial learning, citing a median number of trials to criterion of 9.5 for cooled animals and 11.0 for controls on Day 13 retesting. The median number of shocks received was also similar (3 vs. 2) in both groups. There were also no significant differences in reaching criterion on Day 14 re-testing, nor in the reversal procedure.

Mrosovsky wisely points out in his interpretation of these results that

It must not however be assumed from the lack of evidence that hypothermia readily disrupts retention that behavior is unaltered. In the work of Andjus et al. (1956) and that of Sudak and Essman (1961), while retention was not changed, the ability on problem solving and habit reversal were decreased, even several weeks after the cooling.

He goes on to mention that the “motivating conditions” of those experiments are different from his own, which may explain differences in results, but also says that it may be possible that initial learning is more likely to be altered than retention after hypothermia. According to this hypothesis, he classes hypothermia along with anesthetics in  the category of agents having mild retroactive effects on learning and memory (i.e., those affecting memories consolidated immediately before the interfering event).

Methods to resuscitate rodents from ultraprofound hypothermia

31. December 2008 · Comments Off · Categories: Death, Science · Tags: , , , ,

This is the fifth entry in a series about resuscitation of non-hibernating rodents from circulatory arrest at ultraprofound hypothermic and high subzero temperatures. As we have seen, Radoslav Andjus had determined a method for achieving excellent (75-100%) recovery rates in rats cooled to 0-2 degrees C by local cardiac heating prior to warming the whole body during resuscitation. The basic assumption was that it was necessary to keep oxygen demands in the body at a low level until the heart was able to supply oxygenated blood to the tissues.

However, in simultaneous experiments, Audrey Smith quickly found that hamsters appeared to require whole body warming for resuscitation from ultraprofound hypothermic temperatures. In fact, no hamsters were revived using the local cardiac heating technique, which prompted Smith to question whether it was really necessary for resuscitating rats and other non-hibernating mammals. As usual, the answer to this question was to be determined through experimentation, this time in collaboration with S.A. Goldzveig in 1955 (results were published in the Journal of Physiology in January 1956).

Goldzveig and Smith first replicated previous experiments by cooling 104 rats (150-190 g) to between 0.1 and 1.2 degrees C and attempting resuscitation using local cardiac heating with microwave diathermy. Of these rats, 78 were long-term survivors.

Whole body warming was initially carried out on 12 rats using three 100W bench lamps. The rat was placed supine on a wire grid and two lamps were placed as close as possible to the ventral surface and a third beneath the dorsal surface of the body. Three rats resumed breathing but died soon afterward. The authors reported that “the appearance of the skin suggested that the animals had been overheated.”

So they tried again. This time they placed the two 100 W ventral bench lamps further away, leaving an air gap 5-8 cm from the body. The third lamp was reduced to 60 W and also placed 5-8 cm from the dorsal surface of the body. All twelve of these animals recovered completely, suggesting that the position of the lamps was paramount to recovery. Thinking that intensity of illumination might also be of importance, they played with reducing illumination further: 4 of 6 rats rewarmed using one 40 W and two 100 W lamps recovered completely, but further reductions in illumination did not produce better results. In general, rats resuscitated by local cardiac heating began breathing spontaneously much earlier (within 11-15 minutes) than rats resuscitated by heating the whole body (14-23 minutes), but no other differences in rats recovered by the two methods were observed.

Mice (22-38.5 g) of two different strains (one of which was susceptible to bacterial hepatitis) were used for further cooling experiments. They were cooled in the same manner as rats, but due to having much less body mass they cooled much more rapidly. They ceased breathing between 4.5 and 5 degrees C, and the heart stopped beating between 2.5 and 3.8 degrees C. Mice were left in ice for 55-60 minutes after respiration and heartbeat had stopped.

Two methods of resuscitation of ice-cold mice were attempted. Nine of eleven mice were long-time survivors of local cardiac heating by microwave diathermy (intensity of the microwave was reduced to account for smaller body mass). The first attempt at recovering mice by whole-body illumination under a 60 W bench lamp resulted in a 100% recovery rate, but was followed by 10 delayed deaths at 3 weeks, which upon necropsy were found to be due to fulminating hepatitis. The experiment was repeated using another strain of mice, of which all recovered fully and 19 of the 21 were long-term survivors.

These experiments proved that local cardiac heating is not necessary for complete recovery of adults rats and mice from ultraprofound hypothermic temperature, and, almost as importantly, that a simple bench lamp was as effective as a microwave magnetron in recovering animals from this state of “suspended animation.” Goldzveig and Smith admitted that even these results could probably be improved upon by further manipulation of variables, but stressed that “…from a theoretical point of view, these results are of great importance and suggest that the danger of tissue anoxia has been exaggerated.”

Resuscitation of rats from high subzero temperatures

22. December 2008 · Comments Off · Categories: Death, Science · Tags: , , , ,

This is the fourth entry in a series about resuscitation of non-hibernating rodents from circulatory arrest at ultraprofound hypothermic and high subzero temperatures. Up to this point we have discussed the groundbreaking research in the early 1950s performed by Radoslav Andjus in resuscitating rats from body temperatures between 0 and 2 degrees C. Having determined that preferential heating of the heart improved chances of revival, Andjus perfected the technique a number of times, eventually obtaining a 100% resuscitation rate by use of microwave diathermy. Having established a technique that ensured a high percentage of recovery, he began to investigate other problems related to resuscitation from hypothermia, including the effects of repeated coolings to zero and the possibility of resuscitating rats cooled to subzero temperatures.

In his 1955 publication in the Journal of Physiology, Andjus briefly states that cooling to 0-2 degrees C was performed as described in earlier papers. Cooling to subzero temperatures required immersion of the animal into a bath of propylene glycol between -5 and -20 degrees C. The method of reanimation was microwave diathermy as described previously.

To study the effect of length of time at ultraprofound hypothermic temperatures, Andjus cooled six groups of ten rats to colonic temperatures of 0-1 degrees C, with each group kept cold for a different length of time before attempting reanimation. The “period of suspended animation” ranged from 60-70 minutes to 110-120 minutes in 10 minute increments. Andjus defined the period of suspended animation as that “spent below 15 degrees C prior to the application of heat.”

10 out of 10 animals recovered completely from the group that spent 60-70 minutes in hypothermic circulatory arrest, but the longer the period of suspended animation beyond that, the lower the recovery rate, with 6 animals recovering from 70-80 minutes, 4 from 80-90 minutes, 3 from 90-100 minutes, 1 from 100-110 minutes, and none from 110-120 minutes. Several delayed deaths also occurred in animals revived after 70-100 minutes of “suspended animation.”

Another series of rats was cooled to 0-0.5 degrees C for 60-70 minutes and resuscitated repeatedly. The results of this experiment were extremely interesting. Initially, a rat was cooled and resuscitated every other day for a total of 8 coolings within 16 days. The rat lost a lot of weight, was unable to regulate its body temperature, and died 18 days after the last cooling. The next rat was cooled repeatedly but had longer intervals between coolings and was allowed to regain its initial weight after the first cooling. Interestingly, this rat was able to tolerate a longer periods of suspended animation (80 minutes) after several coolings, and recovered fully from a total of 10 coolings over 43 days.

Other rats were then repeatedly cooled to zero and allowed to regain their initial weight before each cooling. Andjus noticed that the time to regain weight also decreased with successive coolings, noting that “one rat needed 11 days to regain its initial weight after the first cooling, 6 days after the second, and 1-3 days after the third to eight cooling. The means taken from the results obtained with a group of seventeen animals show the same tendency.”

This trend in improved recoverability after repeated coolings appeared to hold true across the board:

Further improvements in the recovery after reanimation were noted in repeatedly cooled rats. For a few hours after the first reanimation and artificial rewarming to 37 degrees C the rat is not able to maintain its normal body temperature in a cold environment. When left in a refrigerator at 0 to +3 degrees C the reanimated rat steadily cools down. By contrast, a number of rats reanimated for the sixth to eighth time were perfectly capable of maintaining their normal body temperature in the refrigerator.

It was also noted that rats reanimated for the first time, and having just resumed their heart beat and respiration, with a body temperature of 15 degrees C (see Andjus & Smith, 1955) were not capable of spontaneous rewarming to 37 degrees C when left at room temperature (21-23 degrees C), and died after a few hours if the rewarming was not completed artificially. By contrast, a number of rats reanimated for the fifth to eighth time spontaneously regained their normal body temperature when left on the bench with colonic temperatures of 15 degrees C.

In addition, one rat cooled for the third time and another for the sixth time tolerated 120 minutes of suspended animation with full subsequent recovery. None of the ten control rats even recovered spontaneous respiration after cooling the first time to zero for 120 minutes.

Finally, Andjus investigated the recovery of rats from subzero temperatures. Some rats were “supercooled,” while others were allowed to undergo ice crystallization. In supercooled rats, both subcutaneous and colonic temperatures dropped steadily to temperatures as low as -5.7 degrees C subcutaneous and -3.3 degrees C colonic and for as long as 40 minutes in the subzero range. Andjus reported that “all rats supercooled without  crystallization were reanimated, recovered completely, and resumed growth.”

Animals that underwent crystallization did not fare so well. Eight of nine recovered heart beat and spontaneous breathing, but all died during rewarming or within 24 hours post-reanimation.

These experiments mark the beginning of investigation into the effects of hypothermic temperatures on mammalian physiology in a number of laboratories. More details about the freezing and supercooling experiments will be discussed in subsequent posts in this series, as well as the ongoing experiments of Radoslav Andjus and Audrey Smith.

Microwave diathermy to resuscitate hypothermic rats

21. December 2008 · Comments Off · Categories: Death, Science · Tags: , , , ,

This is the third entry in a series about resuscitation of non-hibernating rodents from circulatory arrest at ultraprofound hypothermic and high subzero temperatures. Andjus and Smith were delighted that they had managed to modify Andjus’ chest-wall heating technique from using a hot metal spatula to using a focused beam of light in order to preferentially warm the heart before warming the whole body. This modification resulted in a substantially larger percentage of rats fully recovering from ultraprofound hypothermic temperatures as well as a significant reduction in the number of delayed deaths after partial recovery. However, some delayed deaths still occurred, and Andjus and Smith speculated that these were likely due to the inevitable burns caused by these techniques. So Andjus collaborated with J.E. Lovelock to further refine the protocol in an attempt to eliminate peripheral tissue damage during heating, as described in their 1955 article in the Journal of Physiology.

This was accomplished by using a microwave diathermy apparatus “powered by a 500 W continuous wave magnetron operating at a frequency of 3000 Mc/s feeding into an H01 mode waveguide.” An aperture was created in an extension of the waveguide and the animal was placed underneath for preferential heating of the heart. Rise in temperature varied across different parts of the body and was steepest in the left side of the chest.

Cooling was carried out in the same manner described in previous posts, and reanimation procedures began when the animal’s colonic temperature was between 0 and 1 degrees C. In a first series of experiments, warming was carried out using microwave diathermy and artificial respiration was given by means of a hand bulb and tubing inserted into the nostrils and discontinued after spontaneous breathing was reestablished. When the animal reached 15 degrees C it was then placed in a 40 degrees C water bath for whole body rewarming to 33 degrees C, whereupon it was placed in an incubator for 3 days before being transferred to long-term care in the animal facility.

This first series of experiments resulted in an 80% full recovery rate  — already a 5% improvement on the focused light beam method. However, the strong focus of microwaves through the aperture still resulted in occasional burns to the chest wall. With another slight modification to the protocol (the use of a horn radiator to produce a more even field distribution of microwaves), the recovery rate reached 100% and no burns were observed.

Since they appeared to have perfected the method, they performed an exploratory experiment on one rat, cooling it and reanimating it a total of 10 times (each experiment separated by 2-10 days) using the Series II microwave diathermy technique. This rat also recovered fully each time.

From an initial full recovery rate of 20% using the hot spatula method to a 100% recovery rate using microwave diathermy, Andjus demonstrated his grasp of the issues involved in resuscitating rats from ultraprofound hypothermia and a singular dedication to overcoming obstacles. Because of his primary interest in applying these resuscitation techniques to victims of accidental hypothermia and freezing, the road ahead was clear: now that he had a method for reanimating rats that had reached 0 – 2 degrees C, he next wanted to know the time limits to resuscitation (how long can a rat be held at these temperatures and still be successfully revived?), the effects of multiple coolings and reanimations, and — the ultimate question — whether a rat could be frozen and then resuscitated.

He tackled all of these issues in his next publication, which will be discussed in the next post.

Improved methods for resuscitation of cold rats

19. December 2008 · Comments Off · Categories: Death, Science · Tags: , , , ,

This is the second entry in a series about resuscitation of non-hibernating rodents from circulatory arrest at ultraprofound hypothermic and high subzero temperatures. As discussed previously, in 1951 Radoslav Andjus developed a simple method for resuscitating rats cooled to deep body temperatures between 0 and 2 degrees C which involved applying a hot spatula to the left anterior chest wall to warm the heart and re-initiate circulation before rewarming the rest of the body. While he experienced some success with this method, a high proportion of the rats which regained heart beat and respirations died during subsequent warming of the whole body or within a few hours or days of regaining normal body temperature and behavior.

When Andjus met Audrey Smith, they collaborated in 1955 to determine whether the reanimation failures and high mortality rate after initial success were the result of damage during cooling or due to imperfections of the reanimation protocol. They began by comparing Andjus initial cardiac heating method to an alternative method employing a high-intensity lamp to project focused light on the chest wall.

In both protocols, rats were cooled according to the previously described method of placing an animal in a jar and then putting the vessel in a refrigerator. Once rats were cool and lethargic, they were immersed in dishes of melting ice and buried under crushed ice. They remained under ice for exactly 1 hour from the time colonic temperature reached 15 degrees C and for approximately 40 minutes after it had reached 6 degrees C. In general, respirations ceased soon after ice immersion, the heart beat slowed suddenly between 10 and 13 degrees C, and final heart beats were observed at or above 8 degrees C. The rats were removed from ice with body temperatures between 0 and 1.8 degrees Celcius.

When attempting resuscitation using the spatula method, the spatula was warmed in a Bunsen flame and applied as frequently as 20 times per minute. When the first heart beat was observed, artificial respirations began using a small hand-bulb attached to tubing inserted into the nostrils. Local cardiac heating was performed less frequently as heart rhythm became regular, and was discontinued when heart rate increased spontaneously. At 10-11 degrees C the animal’s neck was heated under hot tap water and artificial respirations were continued until spontaneous breathing resumed.

When attempting resuscitation using a beam of light, the rats were placed on a platform under a duralite shield with an aperture that allowed for focusing of the light on the praecordium. The intensity of the light/heat could be controlled by changing the variac setting. The neck was warmed under the light beam when colonic temperature reached 10-12 degrees C and artificial respirations were given until spontaneous breathing resumed. Rewarming of the whole body in both protocols occurred by placing the rats in a 37 degrees C water bath until they could maintain normal posture, at which point they were transferred to an incubator for short-term recovery, then to an warm cupboard for long-term care.

Results obtained by the spatula method were similar to those obtained in Andjus’ initial experiments. Out of 25 rats, 4 exhibited irregular heart beats and then succumbed, 4 exhibited regular heart beats but no spontaneous breathing and were dead within an hour, 6 exhibited spontaneous breathing but no reflexes and died in the 37 degree C bath, 5 exhibited an apparently complete recovery and died within 24 hours, and only 5 survived for more than 66 days.

Results obtained by the beam of light method were better. Using the initial protocol, which involved a large number of changes in variac settings at lower intensities over the course of warming, 11 of 25 rats survived more than 66 days. Modifications to start at a higher intensity and reduce the number of changes in variac settings resulted in 17 of 25 rats surviving more than 66 days, representing a long-term survival rate of 75%. In addition, far fewer (2) delayed deaths occurred using this protocol.

Andjus and Smith speculate about the importance of proper cardiac warming for successful reanimation from ultraprofound hypothermia in their discussion of these landmark experiments:

It is likely that the method of reanimation is of great importance. When an animal with a deep body temperature of 0-2 degrees C is transferred to a hot bath at +45 degrees C as in the experiments of Lutz (1950) the skin and superficial tissues must rewarm rapidly and experience anoxia for many minutes before the heart is warm enough to beat and provide an adequate circulation. If, on the other hand, the heart is rewarmed first and a circulation established before the temperature of the bulk of the body rises, the degree and duration of tissue anoxia may be greatly reduced.

They go on to anticipate improvements in their method beyond those already achieved:

It was remarkable that the revival rate in our experiments was increased from 20 to 75% when local heating on the surface of the chest wall was superseded by heating with a beam of light. The amount of heat penetrating to the anterior surface of the heart was undoubtedly increased when the chest wall was irradiated, but the oesophageal thermocouple showed that the temperature of the posterior aspect of the heart lagged behind. These results suggest that a more efficient method for rewarming the heart rapidly should make it possible to revive all rats from body temperatures between 0 and 1 degree C.

And of course they went on to test this hypothesis, as well. But that’s a topic for the next post.

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