Human physiology under cold exposure.

In order to minimize heat loss cold stress induces peripheral vasoconstriction via the sympathetic nervous system. This effect is most pronounced in the extremities. Vasoconstriction does not appear in the head-neck region--a fact of great importance in emergency situations. In order to compensate for heat loss shivering is an early event, where involuntary muscle contractions increase metabolic rate 2-6 fold. Early tachycardia and elevated blood-pressure, followed by progressive bradycardia and lowered pressure are common cardiovascular effects of hypothermia. Death due to ventricular fibrillation or asystole occurs between 28 degrees-25 degrees C. Cold stress causes an osmolal diuresis with sodium and chloride as the main constituents. The natriuresis is of tubular origin and could be due to impaired autoregulation in the kidney and/or depend on the natriuretic polypeptide. The augmented urine flow decreases blood volume, lowers physical working capacity and increases blood viscosity--all negative events in a hazardous situation. Sudden immersion initiates hyperventilation for 1-2 minutes with an increasing risk of drowning. Thereafter ventilation decreases to rates consistent with metabolic requirements. In severe hypothermia carbon dioxide retention causes respiratory and metabolic acidosis. Hypothermia induces progressive depression of mental functions starting with apathy and bizarre behaviour and ending in lethargy and coma often between 30 degrees-28 degrees C. The paradoxal feeling of heat with undressing in agony could depend on cerebral receptor disturbances.

Alcohol and cold.

Alcohol is a dominant cause of death in urban hypothermia. Drinking alcohol gives a pleasant feeling of warmth. However, experimental studies on humans during relatively short exposure to moderate cold have given inconsistent results concerning heat balance. Longer exposure to colder environmental situations has, particularly with addition of strenous exercise, revealed enhanced heat loss. A warning must be given to drink alcohol beverages in connection with outdoor activities in a cold environment. It gives a feeling of bravery and influences judgement leading to ignoration of prophylactic measures. Alcohol delays the onset of shivering and reduces its duration. It augments cold diuresis thereby diminishing blood volume and physical working capacity. On the other hand, alcohol seems to protect the heart against ventricular fibrillation at low core temperatures. Furthermore ethanol also seems to have some positive properties in freezing cold injuries.

Freezing cold injury.

The pathogenesis of freezing cold injuries (FCI) is not yet entirely understood. Two possible hypothesis emerge: 1) Injury is a direct result of cryogenic insult to the cells. 2) Injury is secondary to vascular stasis which leads to anoxia. In clinical congelatio ice crystallization takes place in the EC-space. When water is transformed into ice, the osmolality in this compartment will increase leading to a passive diffusion of water from the IC-space. Cell dehydration modifies protein structure, alters membrane lipids and cellular pH leading to destructions incompatible with cell survival. Cold induces vasoconstriction of both arterioles and venules, which enhances peripheral filtration and raises plasma viscosity. The stability of red corpuscle aggregates increases and showers of emboli course microvessels. Finally progressive thrombosis will end up in anoxia. The indirect vascular effect has earlier been interpreted similar to that found in non-freezing injuries. Recent studies have, however, shown, that endothelial cells are very sensitive to freezing. The rheologic part of the pathogenesis therefore also seems to depend on a direct injury to cells. The development of FCI does not always depend on ambient temperature and duration of exposure but more to the heat loss subjected to exposed skin. Wind chill, humidity and wetness are all of significance in this matter. From a clinical point of view FCI are best subdivided into superficial and deep injuries. The superficial frostbite is limited to the skin and nearest subcutaneous tissue. A stringing, pinching pain is often the first symptom. The affected area becomes pale or waxy-white and numb.(ABSTRACT TRUNCATED AT 250 WORDS)

Characteristic changes in psychiatric symptoms, cortisol and melatonin but not prolactin in primary hyperparathyroidism.

Psychiatric symptoms in primary hyperparathyroidism (PHPT) are usually characterized as depressive. In this study 13 patients with PHPT and six control patients with atoxic nodular goiter underwent psychiatric ratings with the comprehensive psychopathological rating scale (CPRS) the day before surgery. The 21 items in this scale were grouped into clusters. The ratings were repeated after successful removal of a parathyroid adenoma. Diurnal serum concentrations of cortisol, melatonin and prolactin were studied pre- and postoperatively in eight of the patients. Patients with PHPT had significantly higher CPRS total scores, 8.5 +/- 1.3, compared with goiter controls, 1.9 +/- 0.8, and showed a significant improvement of psychiatric symptoms after excision of the parathyroid adenoma, to 3.3 +/- 0.9. The preoperative diurnal and peak levels of cortisol and melatonin were higher (P less than 0.05) than after surgery. Serum melatonin fell to levels lower than those in healthy controls. Correlations were found between some clusters or items and cortisol or melatonin. Serum prolactin levels were normal and unaltered by parathyroid surgery. It is concluded that patients with PHPT show well defined psychiatric symptoms many of which are correlated to alterations in serum cortisol and melatonin accompanying PHPT. The improvement of symptoms seen after successful surgery further suggests that PHPT is associated with a specific psychiatric disorder similar to but distinguishable from major depressive disorder.

Parathyroid surgery in Scandinavia.

A review of the organization and practice of parathyroid surgery in Scandinavia indicated that it was undertaken in about half of the surgical clinics. About half of these clinics treated only primary hyperparathyroidism (HPT), and in the great majority all parathyroid operations were done by one or two surgeons. The results of surgical treatment were compared in two large Scandinavian series of primary HPT, one based on a general survey of parathyroid surgery in 1975, and the other on results obtained during 1971-1980 in centres specializing in endocrine surgery (Bergen, Stockholm, Uppsala). In the latter series 90% of the patients were normocalcaemic at follow-up averaging 4.4 years after parathyroid surgery whereas in the general survey the rate of normocalcaemia was 76%. At hospitals performing less than ten parathyroid operations per year it was only 70% and there was high incidence of persistent HPT (15%) and presumed permanent hypoparathyroidism (14%). The findings strongly advocate special training and interest in parathyroid surgery in order to ensure success.

Fine-needle biopsy cytology and DNA analysis. Their place in the evaluation and treatment of patients with thyroid neoplasms.

Fine-needle aspiration allows sampling of tissues without surgical biopsy. This technique provides accuracy, speed, patient acceptance, and individual cells for the study of neoplasia. When this procedure is combined with DNA analysis, it is possible to obtain preoperatively additional diagnostic and prognostic information superior to that obtained by clinical and morphologic methods alone. This information is of utmost importance when planning appropriate treatment.

Radiation therapy in operable breast cancer: results from the Stockholm trial on adjuvant radiotherapy.

In a randomized trial, 960 women with Stage 1-3 operable breast cancer were treated by a modified radical mastectomy alone, or by the same procedure, preceded or followed by radiotherapy (4500 rad to the breast/chest wall, and internal mammary, axillary and supraclavicular lymph nodes). Up to ten years after treatment, there is an increasing gap between the recurrence-free survival of the irradiated patients and the surgical controls. Between the two types of radiotherapy, there was no difference. There were significantly fewer distant metastases and a tendency for improved survival in node positive patients treated with postoperative radiotherapy, compared to the surgical controls, this difference was, however, statistically not significant.

Selective venous sampling for localization of hyperfunctioning parathyroid glands.

Selective venous sampling with parathyroid hormone assay was used in 46 patients with primary hyperparathyroidism. All patients had previously been operated on in the neck region. In 80 per cent of the patients the method correctly located the position of the hyperfunctioning gland(s). No complications were observed. The method was found to be of great value when evaluating patients with persistent or recurrent hyperparathyroidism.

Prognostic value of nuclear DNA content in follicular thyroid tumours.

The prognostic value of nuclear DNA content in follicular thyroid tumours was studied in 65 patients. Forty-six (20 with follicular carcinoma and 26 with follicular adenoma) were alive at least 10 years after diagnosis, and 19 had died of follicular thyroid carcinoma 2 months to 13 years after diagnosis. DNA was measured in morphologically identified single tumour cells either on material from fine-needle aspiration biopsy or on histologic sections from the primary tumours. Metastases or locally recurrent tumour were also examined in ten cases. The tumours from the surviving patients had cells with DNA content comparable to that in normal cells, whereas the tumours from the nonsurvivors showed higher DNA values. Primary tumours had essentially the same DNA content as metastases or local recurrence in eight of the ten studied cases. The data suggest that DNA measurement in follicular thyroid tumours offers a valuable addition to standard clinical and microscopic analysis.

Increase in muscular strength following surgery for primary hyperparathyroidism.

The muscle strength of the quadriceps muscle was measured in a computerized modified Cybex II muscle dynamometer. The method used is easy and has an error of greater than 5%. A marked increase in muscular strength was found after successful surgery for primary hyperparathyroidism (PHPT) with normalization of serum calcium levels. The results support the opinion that all patients with PHPT, with or without muscle weakness, should be recommended an operation if no serious contra-indications exist.

Prognostic impact of nuclear DNA content in medullary thyroid carcinoma; a retrospective pilot study.

The prognostic significance of DNA content in medullary thyroid carcinoma was studied retrospectively in 16 patients. Five patients died within 3 years of medullary thyroid carcinoma and 11 patients survived for at least 10 years. Clinical data and tumour morphology were studied. DNA measurements on tumour cells in histologic sections were performed with slide cytophotometric technique. The tumours of the survivors had in all but two cases a DNA content comparable to that of normal cells, whereas the tumours of the non-survivors and two of the survivors had higher DNA content. The results indicate that DNA measurements in medullary thyroid carcinoma might be of use in addition to clinical and morphologic data and that further studies are warranted.

Comparison of nuclear DNA content in primary and metastatic papillary thyroid carcinoma.

Nuclear DNA values were determined in 40 primary papillary thyroid carcinomas, as well as in 52 corresponding local recurrences and metastases were observed either at the time of diagnosis or up to 20 years later. The patient population consisted of 34 survivors and 6 nonsurvivors. In survivors, both the primary tumors and their recurrences and metastases exhibited a majority of cells with DNA values within the normal diploid region, whereas nonsurvivors showed increased and scattered DNA values. In all cases, the primary tumors and the corresponding recurrences and metastases showed similar DNA distribution patterns even if many years had passed between the detection of the primary tumor and the metastases. The results indicate that in papillary thyroid carcinomas, the DNA distribution patterns in the primary tumor and the corresponding recurrences or metastases are generally similar throughout the entire period of disease.