Decrease of anti-Mullerian hormone in genetic spermatogenic failure.

The aim of this study was to compare anti-Mullerian hormone (AMH) plasma levels in patients with azoospermia according to the physiopathology. In a prospective clinical study from April 2008 to March 2009 in University Hospital, we measured AMH levels in 49 consecutive patients with azoospermia. AMH plasma levels were correlated with FSH, inhibin B, bioavailable testosterone plasma levels and testicular volume and compared between nonobstructive azoospermia (NOA) and obstructive azoospermia (OA) and within four physiopathological subgroups of NOA: genetic, cryptorchidism, cytotoxic and unexplained. AMH, FSH, inhibin B, bioavailable testosterone plasma levels and testicular volumes were all related to each other. AMH plasma levels were lower in NOA relatively to OA. Lowest values were observed in cases of genetic NOA and on the other hand, the values observed in case of cytotoxic NOA were as high as the values observed in OA. FSH, inhibin B, bioavailable testosterone and testicular volume were not different between genetic and cytotoxic NOA. These results suggest that the decrease in AMH plasma levels is related to the origin of NOA, with low values in genetic NOA and values similar to OA in cytotoxic NOA. Further studies will be useful to understand the fine regulation of AMH production.

Prediction of body weight changes caused by changes in energy balance.

BACKGROUND: Experimental difficulties have so far restricted knowledge of the effects of energy imbalance on change in body weight. Direct measurement requires that the subjects are kept under dietary supervision for several months while the activity is being measured. MATERIALS AND METHODS: The effects of energy balance can be calculated using a combination of fundamental principles and directly measurable data: the law of energy conservation (increase in combustible energy equals the difference between energy intake and energy expenditure); data on energy expenditure of fat and lean tissues; and data on the composition of added/removed tissue during weight change. RESULTS AND CONCLUSIONS: We obtained an explicit differential equation describing the development of body weight over time, with energy intake and energy expenditure as control variables. Using this model it is possible to isolate and analyse the measured effects of parameters not included in the model, such as age or 'adaptivity' of the body.

Iron stores and haemoglobin iron deficits in menstruating women. Calculations based on variations in iron requirements and bioavailability of dietary iron.

BACKGROUND: Iron stores and haemoglobin iron deficits in menstruating women can be calculated from body iron losses and absorption of dietary iron using recently developed methods. OBJECTIVE: To examine iron balance (iron status) expressed as body iron stores or haemoglobin iron deficits in menstruating women from amounts of iron lost (iron requirements) and amounts of dietary iron absorbed. Calculations are made both of stationary states and of the rate of changes in iron stores (iron status) when any of the two main factors determining iron balance are changed. DESIGN: The study is based on (1) previous and new equations describing relationships between iron absorption, iron requirements (losses), iron stores and/or haemoglobin deficits and (2) published data on iron requirements and their variation in menstruating adult women. RESULTS: Both iron stores and haemoglobin iron deficits are strongly related to iron requirements and absorption of dietary iron and follow the same equations during states of iron repletion and iron deficiency. When, for example, increasing or decreasing the bioavailability of the dietary iron, about 90% of the change in iron stores will occur within 1 y. CONCLUSIONS: There are strong relationships between iron requirements, bioavailability of dietary iron and amounts of stored iron. The observations that a reduction in iron stores and a calculated decrease of haemoglobin iron had the same increasing effect on iron absorption suggest that the control of iron absorption is mediated from a common cell, that may register both size of iron stores and hemoglobin iron deficit, eg the hepatocyte. European Journal of Clinical Nutrition (2000) 54, 650-657.

Patterns of long-term weight changes in overweight developing Danish men and women aged between 30 and 60 years.

OBJECTIVE: To determine, in a retrospective semi-longitudinal study, the pattern of weight changes over 11 y in a population of subjects who developed their overweight as adults. DESIGN: A randomly selected population of 2436 subjects from the County of Copenhagen with ages 30-60 y was followed by body weight determinations on three occasions between the years 1982-83 and 1993-94. SUBJECTS: At the last examination, 660 subjects had attained a body mass index (BMI) of>/=28 kg/m2. Of these subjects, 341 had a self-reported BMI at 25 y of less than 25 kg/m2. RESULTS: In 1994, average yearly weight changes since 1983 ranged between 0.9 and 1.2 kg in the younger (30-40 y) 0.4 and 1.2 kg in the older (50-60 y) men and women during the preceding 11 y. These changes were similar over the two periods of 5 and 6 y. More than half of the subjects had weight gains between 6 and 21 kg, about equally distributed between the two periods. Women displayed larger and more frequent gains than men, as did the younger compared to the older subjects. CONCLUSIONS: The data show that weight changes to attain overweight are highly variable among subjects. However, in most subjects, the weight changes were so small and continuous that simple theories of control by means of fixed 'set points' cannot explain the results. In fact, the weight changes were generally so small that they are unlikely to be reflected in food consumption studies and in studies of macronutrient metabolism.

Iron stores in man in relation to diet and iron requirements.

OBJECTIVE: To calculate iron stores in man and their rates of changes in relation to iron requirements and dietary iron intake and bioavailability. METHOD: Newly established relationships between iron absorption from whole diets and serum ferritin (SF) and between SF and iron stores allow calculations of amounts of stored iron under different conditions (diets, losses) at stationary states when absorption equals losses. Rate of growth of stores can also be calculated. All calculations are based on observations and require no model assumptions. RESULTS: Present calculations of iron stores agree with previously observed phlebotomy values. Differences in intake and bioavailability of dietary iron and in iron requirements had marked effects on amounts of stored iron. A wide range of diets was studied, from a hypothetical high-meat diet typical for early man to diets in developing countries. A new equation is given for the translation of SF into iron stores. Analyses of growth rate of stores under different conditions showed a fast growth from zero iron stores during the first year (reaching about 80% of final amounts) followed by a much slower rate for 2-3 y. A marked inertia was seen in rate of changes in iron stores that was more marked the closer stores were to their stationary states making it difficult to use SF to estimate short term changes in iron absorption in iron replete subjects. CONCLUSIONS: Realistic Western-type diets with good bioavailability can cover iron requirements in most women and can restitute iron stores during lactation. The high prevalence of iron deficiency in menstruating Western women is thus mainly related to a further low bioavailability of iron in present diets. Present analyses also demonstrated an effective control of iron absorption preventing development of iron overload in otherwise healthy subjects even if the diet is fortified with iron and even if meat intake is high.

A fast responding combined direct and indirect calorimeter for human subjects.

The construction and performance of a 5.4 m3 combined direct and indirect calorimeter for human subjects is described. The calorimeter was constructed for studies on human subjects primarily undergoing fast alterations in heat production and heat losses, e.g. after a meal or during physical exercise. A heat sink and a heat substitution principle is used to measure sensible heat losses directly. Evaporative heat losses are determined by measuring water vapour input and output. Indirect calorimetry is performed by measuring output air flow and changes in gas composition of the air entering and leaving the calorimeter. The response times (90%) for sensible heat and evaporative heat were found to be 4 min and 34 min, respectively. Three alcohol combustion tests gave a recovery of CO2 and O2 in the range 92-97%. The recovery of water was found to be in the range 56-89%.

Composition of body weight differences in subjects with the same body height.

OBJECTIVE: To determine the composition of body weight differences in men and women with the same height. DESIGN: A study of a random population sample of Danish subjects, aged 35-65 y. SUBJECTS: An age and sex stratified random sample of 3608 subjects of which 2987 (83%) subjects appeared for study. Of these, 548 men and 498 women were randomly selected for this present work based on their heights. RESULTS: The mean values of the slope of body fat against body fat free mass were 2.88 (s.e.m. = 0.09) in women and 1.84 (s.e.m. = 0.07) in men. There were no significant differences between the different body height classes. CONCLUSIONS: See results.

Organ weights in healthy and apparently healthy Danish infants.

The weights of brain, heart, liver, kidneys, spleen, lungs, and thymus were registered in 222 forensic autopsies of Danish infants aged 1 week to 0.99 year (137 males, 85 females), who prior to death were healthy or apparently healthy based on clinical evidence. Variability of organ weights was estimated, and the relationship between individual organ weights and age, body weight, and body length, and the sum of organ weights was evaluated in relation to age, body weight, and body length. No significant differences were found between males and females, and between the healthy and apparently healthy infants. There was a positive, significant correlation of the individual organ weights with age, body weight, and body length. It was most pronounced for the weight of the brain and least pronounced for the thymus. Am. J. Hum. Biol. 9:35-38 © 1997 Wiley-Liss, Inc.

Fat content affects heat capacity: a study in mice.

The specific heat capacity of the human body is a widely used number in calculations related to studies in energy metabolism and temperature regulation. A value of 3.47 kJ kg-1 K-1 has been used during the last century, but there have been no direct studies on the dependence of this value on the body fat content. We present here results of measurements of the specific heat capacity of lean and obese mice. The mice were killed and heated to 40.6 degrees C, transferred to a calorimeter and the specific heat capacity was determined from body mass of the mice and temperature rise of water in the calorimeter. We measured the fat fraction of body mass (mf), fat free body mass and water content of the mice and found a marked dependency of the specific heat capacity (Cp) on body fat. In obese mice (fat content 52.76% body wt) the heat capacity was 2.65 kJ kg-1 K-1 and in lean mice (fat content 7.55% body wt) the heat capacity was 3.66 kJ kg-1 K-1.

Between-subjects variation in energy expenditure: estimation of the effect of variation in organ size.

The between-subjects variation in energy expenditure over 24 h at a fixed physical activity and corrected for differences in fat and fat-free mass has recently been determined to be 6-7%. New data on the variation between subjects of the weights of the brain, liver, kidneys, heart and spleen together with estimates of the energy expenditure of these organs were used to calculate the part of the between-subjects variation in energy expenditure at a fixed physical activity that is due to this variation alone. The results show that this variation is close to 5%. Thus, a very considerable part of the total between-subjects variation can be explained by differences in the composition of the fat-free mass.

Functional consequences of iron supplementation in iron-deficient female cotton mill workers in Beijing, China.

Eighty iron-deficient, nonpregnant female workers were randomly assigned to ferrous sulphate (60 or 120 mg Fe/d) or placebo treatment for 12 wk. Energy expenditure was estimated during 3 d by heart rate (HR) recording. Production efficiency (PE) was calculated as the ratio of productivity to energy expenditure. In the iron-treated group mean hemoglobin (Hb) increased from 114 to 127 g/L (P < 0.001), mean serum ferritin increased from 9.7 to 30.0 micrograms/L (P < 0.001), and mean free erythrocyte protoporphyrin decreased from 1.01 to 0.49 mumol/L (P < 0.001). Mean HR at work decreased from 95.5 to 91.1 beats/min (P < 0.001), which was inversely correlated with the change in Hb (r = -0.60, P < 0.001). PE increased significantly in the iron-treated group (P < 0.001) and its change paralleled the change in Hb (r = 0.58, P < 0.001). The results show that iron supplementation enabled these women to do the same work at a lower energy cost.

Prevalence and type of anaemia in female cotton mill workers in Beijing, China.

The present study investigates the prevalence and type of anaemia in Chinese female cotton mill workers. The prevalence of anaemia is reported in 447 non-pregnant female workers aged between 19 and 45 years. The mean value for haemoglobin (Hb) was 123 (SD 15) g/l and 150 of the total 447 subjects had Hb values below 120 g/l; thus 34% of the population was anaemic according to World Health Organization (WHO, 1975) criteria. The mean value for free erythrocyte protoporphyrin (FEP) was 419 (SD 215) micrograms/l; 55% of the total population had FEP values higher than 350 micrograms/l and 72% among the anaemic subjects. Serum ferritin (SF) was tested in all the women with a Hb value less than 120 g/l and 71% of them had SF values below 12.0 micrograms/l. Eighty women diagnosed as either Fe deficient or with Fe-deficient anaemia were selected for a diagnostic supplementation trial. They were randomly assigned to FeSO4 (60 or 120 mg Fe/d) or placebo treatment for 12 weeks. Fe supplementation increased mean Hb values from 114 to 127 g/l (P < 0.001) and SF levels from 9.7 to 30.0 micrograms/l (P < 0.001), and decreased mean FEP values from 570 to 277 micrograms/l (P < 0.001). The response rate of Hb in the whole Fe-treated group or Fe-treated subjects with an Hb level less than 120 g/l was 90% or 92% respectively. These findings indicate that the type of anaemia in this population was mainly Fe deficiency. It was also found that in this population the severity of anaemia, not the prevalence, was significantly related to the use of intra-uterine devices (IUD).

Weights of brain, heart, liver, kidneys, and spleen in healthy and apparently healthy adult Danish subjects.

Based on a forensic material of 1,598 autopsies of Danish adults (1,086 males, 512 females ≥ 16 years of age), who prior to death were healthy or apparently healthy based on clinical evidence, the weights of brain, heart, liver, kidneys, and spleen were registered. The variability of organ weights was estimated. Relationships between organ weights and body size, and among organ weights were also evaluated. Males had larger organ weights than females. When organ weights were based on the same estimated fat free mass, interesting differences between the sexes were observed: weights of the heart and brain were smaller in females, but weights of the kidney were the same; weights of the liver were consistently larger in females than in males. Useful comparisons of the data with previous studies were impossible because of differences in the criteria of health and of insufficient numbers. © 1993 Wiley-Liss, Inc.

Within-subjects variation over 10 months in 24-hour energy expenditure at a fixed physical activity programme.

In order to estimate within-subjects variability in 24-hour energy expenditure at a fixed physical activity programme with a physical activity index of 1.30, this quantity was measured in four apparently healthy subjects once a month over 10 months. The coefficient of variation of the measurements was found to be between 2.7 and 4 per cent and in agreement with previously published data.

The effect of long-term dexfenfluramine treatment on 24-hour energy expenditure in man. A double-blind placebo controlled study.

In order to investigate the effect of long-term treatment with dexfenfluramine (dF) on 24-hour energy expenditure (EE), 10 obese females were studied in a double-blind design. Shortly before and 4 weeks after cessation of a 13 months treatment period with either dF (30 mg/day) or placebo (PL) the 24-hour EE was measured. The measurements were performed using a 24 m3 direct heat sink calorimeter with continuous real time measurements of evaporative and sensible heat losses. The patients performed a standardized program of exercise, rest and meals. The measurements were performed at 24 degrees C and at a humidity between 3 and 11 g/m3. Discontinuation of dF treatment did not change energy expenditure significantly from placebo, neither when expressed in kJ/kg lean body mass nor in kJ/kg body weight. After cessation of treatment total 24-hour EE decreased likewise nonsignificantly by 2.9 percent in the dF group and by 4.0 percent in the PL group. EE measured over 24 hours was subdivided into day and night periods and into resting energy expenditure as well as a measurement of the heat losses over a period of 3 hours after a meal. This subdivision of the EE showed similar nonsignificant differences. The conclusion is therefore that dF possesses no significant thermogenic effect during long-term administration in human obese subjects.