Level Of Basal Metabolism Research Articles

Changes in the Basic Metabolic Rate of the Crew under conditions of Eight Months Isolation in a Hermetic Object with a Moderately Hypercapnic Artificial Gas Environment. Message 1

Within the framework of the SIRIUS international project, a study of the basic metabolism of a gender-mixed crew in a sealed object with a moderately high content of carbon dioxide in the artificial atmosphere was conducted. Using mathematical methods, we estimated the basic metabolic rate of a crew of 5 people (3 men and 2 women) at rest for 240 days of isolation when simulating a flight to the Moon in the “SIRIUS-21” experiment. The period of isolation lasted from 4.11.2021 to 3.07.2022. BMR studies were performed twice in the background (on –38–35, –6 days), 7 times during the isolation period (23–25, 50–52, 84–86, 110–112, 154–156, 181–183, 222–224 day) and twice during the aftereffect period (+1–2, +8–9 days). It was found that the basic metabolism in isolation decreased by an average of 6 kcal/kg of body weight per day compared with natural environmental conditions. The crew was isolated from the effects of seasonal lighting changes in a sealed facility, the Ground-Based Medical and Technical Facility (NEK) of the Scientific Research Center of the Russian Federation - Institute of Biomedical Problems of the Russian Academy of Sciences, which does not have portholes, and where artificial lighting was created without seasonal changes. Inside the NEK, the comfort temperature was constantly maintained at +21–23 degrees Celsius and an artificial gas environment was formed, in which the oxygen content was maintained at 21%, carbon dioxide no more than 0.35%. In conditions of isolation from the action of these geophysical environmental factors, seasonal fluctuations in basal metabolism with a wave span of an average of 4 kcal /kg of body weight per day were detected: in the spring calendar season, the level of basal metabolism increased relative to the winter season. Seasonal local maximums and minimums of the basic exchange level for 2 calendar seasons (winter 2021/2022 and in spring 2022) were determined for each of the volunteers. The results obtained in this work can be applied in the field of space physiology to clarify the calculated oxygen reserves and caloric content of the crew’s rations for a long-term space mission, as well as in the design and programming of life support systems and thermal management systems for inhabited hermetic objects.

Energy Metabolism in Human Pluripotent Stem and Differentiated Cells Compared Using a Seahorse XF96 Extracellular Flux Analyzer.

Evaluating cell metabolism is crucial during pluripotent stem cell (PSC) differentiation and somatic cell reprogramming as it affects cell fate. As cultured stem cells are heterogeneous, a comparative analysis of relative metabolism using existing metabolic analysis methods is difficult, resulting in inaccuracies. In this study, we measured human PSC basal metabolic levels using a Seahorse analyzer. We used fibroblasts, human induced PSCs, and human embryonic stem cells to monitor changes in basal metabolic levels according to cell number and determine the number of cells suitable for analysis. We evaluated normalization methods using glucose and selected the most suitable for the metabolic analysis of heterogeneous PSCs during the reprogramming stage. The response of fibroblasts to glucose increased with starvation time, with oxygen consumption rate and extracellular acidification rate responding most effectively to glucose 4 hours after starvation and declining after 5 hours of starvation. Fibroblasts and PSCs achieved appropriate responses to glucose without damaging their metabolism 2∼4 and 2∼3 hours after starvation, respectively. We developed a novel method for comparing basal metabolic rates of fibroblasts and PSCs, focusing on quantitative analysis of glycolysis and oxidative phosphorylation using glucose without enzyme inhibitors. This protocol enables efficient comparison of energy metabolism among cell types, including undifferentiated PSCs, differentiated cells, and cells undergoing cellular reprogramming, and addresses critical issues, such as differences in basal metabolic levels and sensitivity to normalization, providing valuable insights into cellular energetics.

Dynamics of Body Component Composition Indicators in Males During Studying at the Military Medical University

The study of anthropometric indicators and body composition of various categories of the population makes it possible to monitor physical development, conduct health assessments and timely development of preventive measures. The purpose of the study is to evaluate the dynamics of indicators of the component composition of the body of military university cadets during the training period from 1st to 6th year. Material and methods. 387 male cadets (the same persons) were examined during the period of their studies in 1-6 courses. The component composition of the body was studied using bioimpedance measurements. Results. It has been shown that during the first two courses of study (persons 17-18 years old) there is an increase in muscle mass of the trunk by 13.8%, muscle mass of the upper extremities - by 11.4% and lower extremities - by 6.1%, which is explained by the presence intense physical activity. Moreover, during the first year of study, a slight increase in the fat component of the body is determined (5.4%). In the third and fourth years of study, there is a stabilization and slowdown in the growth of the formed muscle and fat masses of the trunk and limbs, characteristic of the transition period from adolescence to adulthood. These trends continued to increase throughout the 5th year of study, but the level of basal metabolism did not change significantly throughout the study. In the 6th year, in relation to the time of admission to university, a general increase in the muscle component of the torso was established by 17.2%, muscle mass of the upper extremities - by 15.8%, and lower extremities - by 9.6%. Over 6 years of study, the fat content in the torso increased by 8.2%, the fat mass of the upper and lower extremities - by 7.5% and 8.0%, respectively, and the level of visceral fat increased by 9.3%. The vital volume of the lungs increased by 12.2% compared to the beginning of the 1st course. Conclusion. The above transformations are obviously due to the continued growth of a healthy organism. Reduced adaptive changes during the training period can be corrected by increasing physical activity, diet and caloric intake.

Effect of the photoperiod of red led lighting during incubation on the growth, hematological and physiological parameters of chicken embryos of Lohmann Brown cross

The effect of various photoperiod modes of red LED lighting on eggs under incubation on the growth, development of visceral organs, hematological profile of blood, stress level, metabolism, chicken embryos and results of incubation of egg of Lohmann Brown cross has bee studied. On the 21st day, with a 24-hour light mode, embryos showed an increase in body length and weight, muscle stomach, liver and spleen, and at 18- and 12-hour mode – body weight, muscle stomach, liver and spleen. In the absence of light and 12-hour light mode, embryos showed lymphocytopenia and neutrophilia, and increased stress levels. At the 24- and 18 hours modes, the intensity of respiration and level of basal metabolism in embryos on the 21st day increased compared to developing embryos in the absence of light and with 12-hour light impact. The 24- and 18-hour modes were superior in terms of number of chickens bred compared to control and 12-hour lighting mode. The hatching under prolonged light was significantly higher than in absence of light and under 12-hour illumination by 1.99–2.33 p.p. and 4.99– 5.33 %, and hatchability – by 2.16–3.32 p.p. and 3.68–4.84 %. The highest embryonic viability during 19–21 days was detected with round-the–clock lighting, and the highest fetal death was detected with 12-hour lighting. Thus, in the practice of incubation of eggs of the Lohmann Brown cross, it is advisable to use continuous red LED lighting, which contributes to intensive development of chicken embryos and visceral organs (muscle stomach, liver and spleen), stress resistance, optimization of metabolism, increased hatching and hatchability.

Assessment of nutritive status and its correction in oncological patients after operations in the hepatopancreatoduodenal zone

Surgical interventions in the hepatopancreatoduodenal zone in cancer patients are associated with high risk of nutritional deficiency in the postoperative period. This feature is due to both the volume of the operation itself (pancreatoduodenectomy), and the predominance of catabolic processes in the early postoperative period. In this regard, the monitoring of the main indicators of carbohydrate, protein and fat metabolism in the early postoperative period becomes fundamental for choosing the correct tactics of nutritional support for this patients. Aim. Improvement of the nutritional status of cancer patients after operations carried out in the hepatopancreatoduodenal zone in connection with malignant neoplasms by means of a comprehensive comparative analysis of the effectiveness of isolated enteral, isolated parenteral and mixed types of nutritional support in the early postoperative period. Material and methods. The examination included 40 patients with an average age of 44.5±6.8 years (15 men, 25 women). All patients for analysis were divided into two groups: the first, the main - patients receiving strictly enteral and/or probe nutrition (n=21), the second, control - isolated parenteral nutrition (n=19). The dynamic of the main predictors of nutritional status in the early postoperative period was assessed: the level of total blood protein, including albumin, lymphocyte count, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity, their ratio - the de Ritis coefficient (as indirect criterion of cytolytic syndrome), total bilirubin. The analysis included the time interval of the enteral and parenteral nutrition in the early postoperative period, together with the number of bed-days required to correct the nutritional status in these patients in an intensive care unit. To objectify and clarify the dynamics of the nutritional status of patients in the pre- and postoperative period, we used the generally accepted scales for assessing nutritional status - Subjective Global Assessment (SGA) Nutritional Risk Index (NRI). Results. According to the SGA and NRI rating scales, the overwhelming majority of patients in the main and control groups (85.7% and 94.7%, respectively) had a normal nutritional status before the operation. In the postoperative period, 4 (21%) patients in the control group showed signs of moderate malnutrition by day 12, which regressed after the enteral nutritional support was connected. There were no statistically significant changes in nutritional status in patients of the main group. The basal metabolic rate in patients of both groups had no statistical differences before surgery (2296±279 kcal/day). On the 15th day of the postoperative period, its increase by 394 kcal/day was recorded in the main group, in the control group an increase in the basal metabolic rate was observed only with the addition of the enteral component of nutritional support, on average, by 321 kcal/day. There was no statistically significant decrease in the level of blood lymphocytes in patients of the main group (p=0.289) in comparison with the traced tendency to lymphopenia (p=0.019) in patients of the control group. The patients of the main group showed a slower regression of the ALT activity, and, accordingly, less increase in the de Ritis coefficient. Conclusion. In patients operated in the hepatopancreatoduodenal zone due to malignant neoplasms, in the early postoperative period, the enteral administration of nutritional mixtures may be preferable, both as an isolated method of nutritional support and as a supplement to parenteral nutrition, given its positive effect on the gastrointestinal tract passage, the level of basal metabolism, the state of the protein-synthetic function of the liver and, indirectly, the degree of cytolytic syndrome.

Circahoralian Rhythms of Body Temperature in Mammals and Birds with Different Metabolism Levels.

The time course of intraperitoneal body temperature has been analyzed in two species of mammals (laboratory C57Bl/6 mice and white-breasted hedgehogs (Erinaceus roumanicus) and in two species of passerine birds (common greenfinch Chloris chloris and Japanese quail Coturnix japonica) with different body weights. Similar sets of basic harmonics appearing synchronously in different individuals have been found in the body temperature spectra of the species studied. The level of basal metabolism in those animal species considerably vary; therefore, the period of fluctuations of body temperature in the range of 10-120 min is not determined by the internal characteristics of the body and, presumably, reflects the influence of an external biotropic environmental factor.

Quantification of Bacterial Metabolic Activities in the Gut by d-Amino Acid-Based In Vivo Labeling.

Herein, we propose a metabolic d-amino acid-based labeling and in situ hybridization-facilitated (MeDabLISH) strategy for the quantitative analysis of the indigenous metabolic status of gut bacteria. The fluorescent d-amino acid (FDAA)-based labeling intensities of bacteria were found to highly correlate with their temporal and steady-state metabolic status. Then, after taxonomic identification of bacterial genera in the in vivo FDAA-labeled mouse gut microbiota, by corresponding fluorescence in situ hybridization (FISH) probes, the metabolic activities of different gut bacterial genera are quantified by flow cytometry, using FISH signals to differentiate genera and FDAA signals to indicate their basal metabolic levels. It was found that Gram-negative genera in the mouse microbiota have stronger metabolic activities during the daytime, and Gram-positive genera have higher activities at the night. Our strategy will be instrumental in deepening our understanding of the highly complex microbiota.

Quantification of Bacterial Metabolic Activities in the Gut by d‐Amino Acid‐Based In Vivo Labeling

AbstractHerein, we propose a metabolic d‐amino acid‐based labeling and in situ hybridization‐facilitated (MeDabLISH) strategy for the quantitative analysis of the indigenous metabolic status of gut bacteria. The fluorescent d‐amino acid (FDAA)‐based labeling intensities of bacteria were found to highly correlate with their temporal and steady‐state metabolic status. Then, after taxonomic identification of bacterial genera in the in vivo FDAA‐labeled mouse gut microbiota, by corresponding fluorescence in situ hybridization (FISH) probes, the metabolic activities of different gut bacterial genera are quantified by flow cytometry, using FISH signals to differentiate genera and FDAA signals to indicate their basal metabolic levels. It was found that Gram‐negative genera in the mouse microbiota have stronger metabolic activities during the daytime, and Gram‐positive genera have higher activities at the night. Our strategy will be instrumental in deepening our understanding of the highly complex microbiota.

COMPARATIVE ANALYSIS OF THE DYNAMICS OF IMMUNE-ANTIOXIDANT STATUS OF THE ANTIOXIDANT SYSTEM IN PATIENTS SUFFERING FROM HYPOTHYROIDISM AND COPD

Aim . To carry out a comparative study of the features and shift tendency of individual indicators of the antioxidant system in patients with hypothyroidism and COPD of various phenotypes. 79 patients suffering from COPD III and IV were examined at the age of 60 to 80 years (men and women) who were hospitalized in the pulmonology department of the Regional Clinical Hospital No. 2 in Krasnodar, along with 47 patients suffering from hypothyroidism. Materials and methods. The state of the blood antioxidant system was assessed by the activity of erythrocyte catalase and superoxide dismutase, the level of reduced thiol groups of erythrocytes, and the amperometric index of the total antioxidant activity of blood plasma. The activity of catalase was studied in the hemolysate of erythrocytes according to the method of Beers R. Results. It was established that there were significant changes in the functioning of individual links of the antioxidant protection system in patients with COPD and hypothyroidism, as well as the stress in the system in general. At the same time, enzyme activity of the antioxidant system of erythrocytes varies in multidirectional ways, whereas the indices of the cellular and extracellular non-enzyme links of the endogenous antioxidant system change in a unidirectional way towards the decrease, which may indicate a significant activation of free radical oxidation processes and partial depletion of the low-molecular antioxidant blood link. Conclusion. The revealed imbalance in the pro-/antioxidant system requires the introduction of drugs with antioxidant activity into therapeutic regimens. In patients with COPD, hypoxia and chronic inflammation may provoke oxidative stress, while in patients with hypothyroidism –decrease in the level of basal metabolism and anabolic processes in general.

Evolution of alternative foraging tactics driven by water temperature and physiological constraints in an amphibious snake

Amphibious predatory ectotherms live and forage in two environments (aquatic and terrestrial) that can drastically differ in temperature means and variance across space and time. The locomotor performance of ectotherms is known to be strongly affected by temperature. However, how differences in water temperature may drive the evolution of alternative foraging tactics in amphibious animals remains poorly understood. Fish-eating Viperine snakes Natrix maura occur from high altitude cold water streams to warm shallow lakes, and employ two main feeding strategies: sentinel foraging (underwater sit-and-wait behaviour) and active foraging (fish chasing). Using 272 juvenile snakes we measured: the performance kinetics of diving and swimming in a wide range of water temperatures; basal metabolic levels in relation to body temperature; and the type of foraging mode expressed in water-temperature-acclimated snakes. Individual swimming performances increased with testing temperature (10, 15, 20, 25 or 30 °C). Apnoea time followed an opposite trend however, plausibly reflecting the fact that oxygen demands are related to the metabolic rate of ectotherms. That is, snake heart rates increased with body temperature. Snakes acclimated to 10 °C water mostly displayed sentinel foraging. By contrast, 20 °C and 30 °C water-acclimated snakes were extremely active fish chasers. Individual apnoea times at the various testing temperatures were all correlated; as were individual swimming speeds. There was however no clear relationship between an individual's ability to hold its breath and its ability to swim, suggesting that both performance traits may be the target of different selective pressures. Fast swimming speed and long breath holding abilities are likely key determinants of both foraging success and predatory evasion, although in a context dependent manner. Active swimming foraging is likely to be advantageous in warm water (> 20 °C), while sentinel foraging appears better suited to cold water (< 14 °C). The physiological aspects of foraging tactics of amphibious snakes combined with field and laboratory observations support the idea that physiological and environmental constraints may generate shifts in habitat use and associated foraging tactics in amphibious ectotherms. Avenues for further research are discussed. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 115, 411–422.

Quantitative genetics and fitness effects of basal metabolism

The physiological requirements of reproduction are predicted to generate a link between energy, physiology and life history traits. Simultaneously, low maintenance costs, measured by energy consumption, are expected to be advantageous. Here we investigated fitness relatedness of traits by estimating genetic correlations between, and inbreeding depression for, body mass, basal metabolic rate (BMR) and other life history characters in a wild rodent, Myodes glareolus. The narrow-sense heritability of absolute and mass corrected BMRs were high for females (h 2 = 0.48 and 0.42) but low and non-significant for males (0.32 and 0.09). A significant positive genetic correlation between BMR and litter size suggests that traits connected to female fecundity might favour higher metab- olism (i.e. support increased intake hypothesis). However, the estimates of inbreeding depression indicate that, while higher values of body mass and female litter size could be positively associated with overall fitness, the association between BMR and overall fitness in bank voles would be negative (i.e. support compensation hypothesis). This result sug- gests that the advantages of larger litters and larger body mass might be evolutionary constrained by high costs of maintenance of those traits, as reflected by the level of basal metabolism.

Parameters of thermal homeostasis and psychophysiological monitoring in the evaluation of the phasic structure of adaptation during 240-day isolation

Psychophysiological (PPM) and thermal homeostasis monitoring independently detected four phases of human (N = 4) adaptation to prolonged isolation in a simulator of the Mir station. The results, which reflected adaptive reactions in different functional systems of the body, were compared using identical methods of analysis of variance and correlation and factor analyses with two independent versions of the division of 240-day isolation into phases. In spite of the manifestly individual character of temperature (T) responses, the significance of phasic differences of eight thermal homeostasis (THS) parameters was high, especially in the case of the combined effect of the factors phase and individuality on rectal T and the chest-foot T gradient at the level of basal metabolism. The similarity of patterns of changes in PPM and THS parameters was significant, confirming the phasic character of responses in the thermoregulation system and the working hypothesis that adaptive processes in the human body have their own biological rhythms with a period (ca. 60 days) longer than that of circadian and shorter than that of seasonal rhythms. The dynamics of rectal T, weighted mean body T, and the chest-foot longitudinal gradient was most similar to that of PPM indices. A direct correlation was found between (a) average intraday concentration of cortisol in saliva, on the one hand, and deep body T and longitudinal T gradient (r = 0.52; P <0.05), on the other, and (b) heart rate and weighted mean body T at the level of basal metabolism. It is recommended to supplement four PPM parameters by one or two informative THS parameters that are convenient for direct recording. The parameter of choice is the chest-foot T gradient, much studied under normal and test conditions. It takes a subject only 1–2 min to obtain results and enter them in the PPM data bank file when this gradient is used.

Effects of GABA A receptors activation on brain glucose metabolism in normal subjects and temporal lobe epilepsy (TLE) patients. A positron emission tomography (PET) study Part II: The focal hypometabolism is reactive to GABA A agonist administration in TLE

Positron emission tomography (PET) using [ 18F]fluorodeoxyglucose (FDG) was used to study the metabolic response of focal hypometabolism to the administration of a specific GABA A agonist (4, 5, 6, 7-tetrahydroisoxazolo[5, 4-c]pyridin-3-ol), THIP, in six temporal lobe epilepsy (TLE) patients. After THIP injection, the increase of glucose metabolism in the hypometabolic focus was larger than the mean increase reported in the whole brain (Part I; Epilepsy Res., 19 (1994) 45–54). Within the hypometabolic focus, this increase was significantly higher in regions with the lowest basal metabolic level. This metabolic response in the hypometabolic focus, observed in the absence of any epileptic discharge during FDG accumulation and PET data acquisition, suggests that GABA A receptors are up-regulated or, at least, preserved in TLE.

Effects of simulated increased gravity on the rate of aging of rats: implications for the rate of living theory of aging

Ever since Pearl proposed the rate of living theory of aging numerous studies have demonstrated its validity in poikilotherms. In mammals, however, satisfactory experimental demonstration is still lacking because an externally imposed increase of basal metabolic rate of these animals (e.g. by placement in the cold) is usually accompanied by general homeostatic disturbance and stress. The present study was based on the finding that rats exposed to slightly increased gravity are able to adapt with little chronic stress but at a higher level of basal metabolic expenditure (increased ‘rate of living’). The rate of aging of 17-mth-old rats that had been exposed to 3.14 times normal gravity in an animal centrifuge for 8 mth was larger than of controls as shown by apparently elevated lipofuscin content in heart and kidney, reduced numbers and increased size of mitochondria of heart tissue, and inferior liver mitochondria respiration (reduced ‘efficiency’: 20% larger ADP: 0 ratio, P < 0.01; reduced ‘speed’: 8% lower respiratory control ratio, P < 0.05). On the other hand, steady-state food intake per day per kg body weight, which is presumably proportional to ‘rate of living’ or specific basal metabolic expenditure, was about 18% higher than in controls ( P < 0.01) after an initial 2-mth adaptation period. Finally, though half of the centrifuged animals lived only a little shorter than controls (average about 343 vs. 364 days on the centrifuge, difference statistically nonsignificant), the remaining half (longest survivors) lived on the centrifuge an average of 520 days (range 483–572) compared to an average of 574 days (range 502–615) for controls, computed from onset of centrifugation, or 11% shorter ( P < 0.01). Therefore, these results show that a moderate increase of the level of basal metabolism of young adult rats adapted to hypergravity compared to controls in normal gravity is accompanied by a roughly similar increase in the rate of organ aging and reduction of survival, in agreement with Pearl's rate of living theory of aging, previously experimentally demonstrated only in poikilotherms.

Ecological aspects of winter dormancy in the striped skunk (Mephitis mephitis)

Seasonal surface activity patterns of captive and free-ranging skunks at Delta Marsh, Manitoba, Canada, were determined using radio telemetry and visual observations. Activity decreased sharply between September and mid-December, and was virtually nil between December and early April. Surface activity resumed in March and increased sharply in April to summer levels.Body temperature (Tb) was studied in two individuals in July and three individuals in other months using abdominally implanted radio transmitters. Mean Tb, maximum diel range, and minimum Tb were 37.7, 2.2, and 36.2 °C respectively in July, and 34.4, 7.2, and 28.4 °C in January.Body fat content of adult males, determined by ether extraction, was 32% of live weight in October, and 10% in late April and early May. Theoretically, the skunks experience an energy deficit of 44% if they exist at basal metabolic levels for a winter period of 140 days. The winter reduction in surface activity, the retreat to a relatively warm den, and the winter depression in body temperature permit the striped skunk in the northern portion of its range to survive the winter relying exclusively on stored fat as an energy source, without resort to true physiological hibernation.

Mechanisms in Acute Oliguric Renal Failure Induced by Tetracydine Infusion

Tetracycline hydrochloride (TC), 30-70 mg/kg infused intravenously in dogs in the course of a few minutes, reduced clearance of inulin (Cin) and p-aminohippuric acid (CPAH) on an average to less than 5% of control. In spite of increased intrarenal pressure (approximately 50 mm Hg), electromagnetically recorded renal blood flow was preserved, indicating that the reduction of Cin and CPAH resulted from tubular obstruction, not renal vasoconstriction. The metabolic rate of the cortex and outer medulla fell to 69% of control after TC, as measured by the heat accumulation rate. Further reduction to basal metabolic level (30% of control) was reversibly produced by elevating ureteral pressure, suggesting that the high metabolic rate was caused by continued active reabsorption of sodium chloride at about half the control rate. Thus Cin greatly underestimated glomerular filtration rate in the TC-damaged kidney. From these results and the observation of TC-containing casts in the medullary tubules, we conclude that TC caused tubular obstruction and that leakage of inulin and PAH from the tubules occurred mainly distally to the major sodium-reabsorbing tubular segments.

Hypothermic Behavior in the Hispid Pocket Mouse

Observations on body temperature and metabolism in the cold have shown a clear hibernation response in Perognathus hispidus . The thermal conductance (0.16 cc O2/g-hr-°C) was at an average value for a mammal of this size. The body temperature of the quiet animal was 36.2°C and the basal metabolic level was 1.28 cc O2/g-hr.

Thiouracil in angina pectoris

Of eight patients with angina treated with thiouracil, five were improved, two unimproved, and one, though showing some evidence of improvement, had not been observed long enough to permit classification of the result. The two that did not respond were treated for three months and six weeks respectively. One of these, with severe angina, showed a change in the basal metabolic rate from minus 15 to minus 18 per cent. The other, with mild angina, dropped from plus 1 to minus 2 per cent. The patient with the unclassified result had a mild angina, was treated for two months, the metabolism changing from plus 2 to minus 12 per cent. By contrast, the five who improved were treated for eight, six, seven, eight and six months, respectively, an average of seven months. Little if any improvement became manifest before two months had elapsed. The lowest basal metabolic levels reached in these patients were minus 24, 22, 23, 23 and 20 per cent. In patients B. W. and L. B. myxedema developed at four months and five months, respectively. Bilateral thyroid enlargement appeared in patient O. H. at the end of eight months' treatment. This constitutes valid evidence for the ability of thiouracil to suppress the normal thyroid if it is administered consistently over a long enough period of time. Toxic reactions to the drug offered little interference in the treatment of this small group. Patient M. C. developed gastric distress at the onset which disappeared quite promptly. Patient O. H. developed joint pains and headache on the sixth day, which cleared on stopping medication for one week and did not recur on a lower dosage level. Propyl-thiouracil, because of its lesser toxicity, was substituted for thiouracil in three patients after improvement had appeared. In patient L. B. three months' administration at 75 to 125 mg. daily failed to hold the gain made with thiouracil. One hundred mg. daily over a three months' period held the ground previously gained by patients O. H. and J. K. Four of the five improved patients continued symptom-free without further treatment: Patient B. W. for four months, patient M. C., three months, and patients O. H. and J. K. one month each. In accounting for this and the improvement in general, it may well be claimed that a period of time alone, comparable to that devoted to treatment with thiouracil, would be sufficient to permit development of enough collateral circulation to overcome the anoxia and pain. While this might account for the ultimate improvement and freedom from attacks after treatment had been terminated, it would make no allowance for the part played by the thiouracil in lowering the metabolism, reducing the demands on the heart muscle, and in decreasing the latter's sensitivity to adrenalin. This action, though slow in developing, is apparently instrumental in controlling the symptoms in angina while modification of existing circulatory deficiencies is being accomplished through improvement in the collateral circulation.

The relation of basal metabolic gain during pregnancy to nonpregnant basal metabolism

The relationship between the nonpregnant basal metabolic level and the basal metabolic gain during pregnancy was investigated in 158 women of the Fels Research Institute series.Women who had the lowest nonpregnant basal metabolic rates tended to have the greatest pregnancy gains. Possible explanations of this finding, as well as a discussion of the exceptions which occur, are presented.In the Fels nonpregnant series, 44.8 per cent of the women had basal metabolic rates below −10 per cent on the basis of the Mayo Clinic standards. Basal metabolic rates during the ninth month of pregnancy were preponderantly at the level which would usually be considered normal for nonpregnant women. These facts can probably be explained on the basis of differences in the conditions under which various basals are measured.The low basal metabolic rates observed in the Fels series were compared with Davis' Milwaukee and Wilmington series, which also showed low values. The possible need for interpretation of test results in terms of the environment, significance the patient attaches to the test, general anxiety, and previous test experience is suggested.

FURTHER STUDIES ON THE OVARIANTHYROID RELATIONSHIP1

MANY METHODS have been used to study the relation of the ovaries to the thyroid glands. Van Horn (i) reported that three rat units of theelin were necessary to produce estrus in experimental hyperthyroid rats. Gessler (2) reported a decrease in basal metabolism in guinea pigs with the use of folliculin. Collett, Smith and Wertenberger (3) found that theelin, theelol or amniotin increased the basal metabolism of ovariectomizd women. Sherwood et al. (4) showed that thee lin and amniotin lowered the basal metabolism of ovariectomizd rats. The author also showed in the above investigation that amniotin lowered the basal metabolic level in experimental hyperthyroid rats. Grumbrecht and Loeser (5) investigated the relation of ovarian to thyroid function through a study of structural changes in the thyroid gland. They suggested that ovariectomy caused a flattening of the epithelial cells and allowed a storage of colloid. It is suggested that the thyrotropic hormone was in creased as a mechanism of defense agains...