Search

In the 1950's many IDF soldiers were hospitalized for heat stroke--about 25% of whom died. Analyzing these cases revealed that commanders misinterpreted human ability to perform in the heat and ignored basic concepts of fluid and electrolyte balance and heat load. In the early 1960's a series of studies was conducted with regard to soldiers' performance in the heat. The first study (1959), which later became a classic, was conducted during a 21-day march from Eilat to Metula, crossing all climatic zones of Israel. The study was followed by other investigations which approached the issues of voluntary dehydration, fluid consumption vs sweat loss, salt additives, and the effect of heat load on performance. Based on these early studies, proper regulations were issued to field officers. Over the years, the lessons learned from these studies saved many lives. The number of cases of heat stroke and of other climate-related injuries was dramatically reduced, and performance was enhanced.

Exertional heatstroke is a syndrome occurring in the young and active population when homeostatic thermoregulatory mechanisms are unable to meet the demands of heat stress. In most cases its occurrence is sporadic and it is regarded as an extreme medical emergency that might result in death if not immediately diagnosed and properly treated. Following some simple regulations and providing proper instructions have proven efficient in preventing this serious disease.

To elucidate factors possibly influencing the outcome of colchicine therapy in patients with amyloidosis of familial Mediterranean fever (FMF).Retrospective analysis of data abstracted from the charts of all 68 FMF patients with amyloidosis who presented during the study period (1974-1992) with proteinuria (or = 0.5 gm/24 hours) and creatinine valuesor = 2.5 mg/dl, received colchicine, and were followed up foror = 5 years.At the end of the study period, kidney disease had worsened in 31 patients and remained stable in 22. Proteinuria had regressed in 15 patients. Deterioration was related to initial serum creatinine valuesor = 1.5 mg/dl (P0.01) and to mean colchicine dosageor = 1.5 mg/day (P0.001). The 3 groups were comparable in terms of initial urinary protein levels, duration of proteinuria, presence of hypertension, occurrence of febrile attacks, sex distribution, and proportion of non-compliant patients.The therapeutic dosage of colchicine for amyloidosis of FMF is1.5 mg/day. This dosage is effective only in patients with initial serum creatinine levels1.5 mg/dl.

A young Caucasian male, otherwise healthy, had had generalized anhidrosis since early childhood. During heat stress tests (40 degrees C, 40% relative humidity), he was found to be heat intolerant since sweat was not apparent. His reaction to muscarinic stimulation of sweat glands was 10% of normal. On biopsy, the sweat glands were morphologically intact, and function of his cardiovascular autonomic responses was normal. The patient's mother reported reduced sweating and her response to muscarinic stimulation was 50% of normal, but his father and both sisters sweated normally. The data suggest a post-ganglionic defect, which may be genetic. To our knowledge this is the first reported case of familial generalized anhidrosis without anatomopathological lesions affecting sweat glands.

Serum glucose and lactic acid levels were determined in 20 young volunteers prior to and following marches with increasing back pack loads (30 and 35 kg) and distances (6 and 12 km). The drop in serum glucose levels correlated well with the degree of effort. A significant mean drop in serum glucose level of 10.3 mg% was detected only in the group carrying 35 kg for a distance of 12 km. In this group, objective physiological parameters as well as subjective grading of the march's difficulty indicated the effort to be strenuous. Serum lactic acid level did not change significantly following any march. Serum glucose level may serve an indicator for determination of work's duration and intensity, determination of optimal distances for untrained hikers and of optimal loads to be carried for various distances.

Pathophysiological effects of exposure to Finnish sauna (80 to 90 C, 30 to 40% relative humidity) were investigated in 60 volunteers--33 men and 27 women aged between 18 and 63 years. The volunteers entered the sauna after a rest period of 20 min, and remained there for 20 min or until they suffered discomfort. Weight, height, rectal and skin temperatures, blood pressure, heart and respiratory rates and ECG were recorded 20 min prior to the sauna, during the sauna, and 20 min after leaving the sauna. Marked physiological changes appeared in the first few minutes in the sauna without any prodromal warning. At the 20th min the mean heart rate was 143 +/- 25 (SD) beats/min (greater than 160 beats/min in 32% of the subjects). Mean rectal temperature was 38.6 +/- 0.6 (SD) C (greater than 39 C in 22%): mean skin temperature was 40.4 +/- 1 (SD) C (greater than 40 C in 35%); mean systolic blood pressure was 130.5 +/- 26.6 (SD) mm Hg (greater than 160 mm Hg in 17%); and mean diastolic pressure was 66.6 +/- 15.9 (SD) mm Hg (greater than 50 mm Hg in 17%). The mean total sweat loss was 457 +/- 264 (SD) g. Three subjects experienced syncope, and one developed an anginal attack; ECG changes suggestive of coronary insufficiency were recorded. No decrease in blood pressure occurred in patients with preexisting high blood pressure. It is concluded that sauna bathing involves dangers to the bather's health, which may appear suddenly, without prodromal warning signs.

Twenty young men marched 6 and 12 km with a well-fitted back-pack load of 30 or 35 kg. Each subject served as his own control. No significant increase in mean heart rate, rectal temperature, or decrease in mean VO2 max and serum levels of glucose and muscle enzymes were recorded in the groups marching 6 km with 30 and 35 kg. Significant differences in the increases in mean heart rate, the decreases in VO2 max and the changes in blood glucose were noted between the two groups carrying 30 and 35 kg for 12 km. These significant differences were also supported by the subjective feelings of the volunteers. The present study shows the optimal back-pack load for healthy young men, marching at 6 km/hr on a paved level road to be 30 kg for 12 km and 35 kg for 6 km without considering the task too difficult and with no significant decrease in VO2 max. The results are relevant to hiking, rescue assignments, and military missions.

Sixty subjects, 33 males and 27 females, from 18 to 63 years of age, were exposed to two kinds of saunas: the Finnish sauna (dry sauna) with an air temperature of 80 to 90 C and a relative humidity of 50%, and the wet sauna with an air temperature of 45 to 50 C and a relative humidity of 100%. There was a rest period of one week between the two experiments. For the 60 subjects the mean duration in the wet sauna was 19.6 minutes and in the dry sauna it was 17.4 minutes. After 10 and 20 minutes of exposure in the wet sauna the mean rectal temperature was 38.1 and 38.5 respectively, the mean skin temperature 40.2 and 40.4 C, the respiratory rate 21 and 22.9 breaths/min, the pulse rate 113 and 135.4 beats/min, the mean diastolic pressure 76.1 and 71.9 mm Hg, and the mean systolic pressure 115.7 and 123.5 mm Hg. Comparing the different physiological parameters in both saunas showed significant differences only during the first 10 minutes: a greater drop in diastolic blood pressure, a higher increase in systolic blood pressure, and a greater rise in pulse rate in the dry sauna. After 20 minutes there were no significant differences between any of the above parameters. It is concluded that the heat strain and hence the risk in both saunas are similar and exposure in either sauna exceeding 10 minutes may be dangerous.

Two sisters whose parents shared a grandfather had cold-induced sweating. Since childhood they had sweated profusely from the back and chest when exposed to environmental temperatures of 18 degrees to 7 degrees C. They had additional abnormalities--e.g., high palate and inability fully to extend the elbows--which neither their parents nor their sibs shared. The cold-induced sweating, which could not be stopped by a beta-adrenergic blocking agent, was abolished by postganglionic blockade with atropine sulphate. This indicates the possibility of a peripheral mechanism.

The sensation of hyperperspiration is a common complaint in hot, humid climates. 54 men and 20 women, 18-47 years old, who had this complaint and 27 male control subjects were examined at rest and after 1 hour of mild exercise (40W) under conditions of heat stress (37 degrees C, 50% relative humidity). During exposure to heat rectal and skin temperatures and heart rate were measured every 15 min. Sweat rate was calculated for the entire period of exposure and sweat gland density was measured at 0, 60 and 120 min. Only insignificant deviations from baseline values were noted at rest. During exercise the sweat rate of the men with the complaint was within normal limits and similar to that of the control men (285 +/- 75 ml/m2 vs 272 +/- 48). Matching for age and V02 max revealed no significant differences in physiological responses of men with and those without the complaint. Women with the complaint lost 25-30% less fluid (226 +/- 67 ml/m2) and their concentrations of active sweat glands were lower than in either of the male groups. 2 men and 1 woman with the complaint and 1 control lost 400-425 ml/m2 during exercise, the upper limit of normal. Only 1 subject showed hyperperspiration (855 ml/m2) during the test. All physiological parameters examined in these 5 subjects were within normal limits. It is concluded that the complaint of hyperperspiration in our self-selected group is basically a subjective feeling and has no pathological basis. None of the subjects was heat intolerant.

Insulin, calcitonin and parathyroid hormone subjected to one of two procedures-acidification and heating or incubation with mouse kidney lysosomal extracts-assumed a nonbranching fibrillar structure, 7 to 10 nm in diameter. The preparations showed green birefringence after Congo red staining. The in vitro synthesis from different hormonal polypeptides of fibrils, fulfilling the criteria for the identification of amyloid, indicates that these criteria are related to conformational rather than to compositional properties, and suggests that these hormones may provide the subunit of the amyloid formed in the corresponding endocrine organs.

ADA of human serum was demonstrated and investigated with an agar gel diffusion technique using amyloid-impregnated agar plates. Sera of 20 healthy adults, 40 patients with AA-amyloidosis, and 86 nonamyloidotic patients were tested. The presence of an ADF, showing enzymatic properties and strongly bound to albumin, was demonstrated in normals and amyloidotic and nonamyloidotic patients. ADA in the serum of amyloidotic and cirrhotic patients was markedly decreased due to the presence of an inhibitor of ADF. ADA of amyloidotic sera was restored to normal by EDTA, citric acid, and ascorbic acid. The ADA of 16 FMF patients and four of 34 patients with rheumatoid arthritis without amyloidosis was intermediate between normal and amyloidotic values, indicating the presence of lADF at low concentrations in these patients. These findings suggest that amyloid is a normal protein metabolite, possibly with a high metabolic turnover. Accumulation of amyloid may be caused by decrease of the ADA of the serum by its inhibitor, rather than by accelerated production.

Long-term follow-up shows a low recurrence rate for Solcoderm treated small superficial basal cell epithelioma, and a high recurrence rate for larger malignant skin lesions.

Amyloid was obtained in recipient mice by implantation into their peritoneal cavity of a dialysis bag containing spleen cells obtained from donor mice which were treated with casein for 6 days and while no amyloid was found in their implanted spleens. The transplantations were performed with 2 cell systems, one containing whole spleen suspension and the other washed cells. Amyloid was obtained in the recipient mice within 6 days after the implantation and in a more massive quantity than in mice treated by casein for a similar period.

The extent to which plasma endotoxin concentrations increased was measured in 89 randomly selected exhausted runners who required admission to the medical tent for treatment in the 1986 Comrades Marathon (89,4 km). Eighty-one per cent had concentrations above the upper limit of 0,1 ng/ml ('endotoxaemic'), including 2% above 1 ng/ml (the reported lethal level in humans), and only 19% had normal levels. There was a negative correlation between plasma endotoxin and plasma anti-endotoxin IgG concentration (P less than 0,025). Those runners completing the race in less than 8 hours had a significantly lower average endotoxin value than those taking longer than 8 hours (P less than 0,025). Also 80,6% of runners (58/72) with high plasma endotoxin values reported nausea, vomiting and/or diarrhoea, compared with 17,7% (3/17; P less than 0,001) with low endotoxin values. Elevated plasma endotoxin concentrations of 32 randomly selected endotoxaemic runners had returned to normal 1-3 weeks later, and most of them (25/32) had increased anti-endotoxin IgG concentrations (P less than 0,02). Fifty-nine runners randomly selected in a short run (21,1 km) 3 weeks after the 89,4 km run completed the race without problems and none showed any increase in endotoxin levels. Further studies in this field are warranted, especially the measurement of endotoxin and anti-endotoxin values from commencement of training to full fitness. It is possible that these measurements may prove useful as predictors of an athlete's or combat soldier's performance.

Twenty-two patients, 18 years old, with the predominant somatic type of NCA, and a control group of 22 healthy subjects participated in a short term training course lasting three weeks. Following the training the NCA subjects showed a significant change in the systolic and diastolic blood pressure after 5 minutes of recumbency as well as in the systolic blood pressure after 5 minutes of standing, diastolic pressures during 50 W load and submaximal effort (100-150 W) - all the values being significantly lower following the training, except the diastolic pressure during 50 W load which was higher following the course. The prominent training effect was on the heart rate during light work loads (50 W) in which a decrease from a mean of 151.2 +/- 13.9 to 118.3 +/- 16.3 beats/min was recorded. This decrease indicates the better adaptation of the NCA patients to physical effort. Similarly, a significant increase in the mean VO2max from 31.5 +/- 6.1 to 37.7 +/- 5.9 ml O2/kg B.W./min was observed. No changes were recorded in the ECG after the short training course. Following the training all the symptoms typical of the NCA syndrome vanished. A short physical training of 3 weeks can start the procedure of rehabilitation of a well selected group of NCA patients with predominant somatic complaints. The rehabilitation must be continued throughout life by continued physical training.

Orthostatic examinations were performed with a tilt table on 64 male volunteers, of whom 21 had sustained amputation of one or both lower limbs and 23 were paraplegic due to spinal cord injuries (SCI), with 20 healthy subjects as controls. Following tilting, signs and symptoms of fainting appeared in five of the SCI subjects, four of whom had spinal injuries above the level of D5. These phenomena appeared in only two of the controls and in none of the amputees. The mean systolic and diastolic blood pressures of the amputees at rest and standing were higher than those recorded in the other two groups. The mean pulse pressures were lower in the amputees than in the other two groups. The changes in the systolic, diastolic, and pulse pressures were more profound in those subjects with high spinal cord injuries than in subjects with lower cord injuries. ECG changes and fainting were more frequent among the SCI subjects than in the other two groups.