Effects of the sex-linked dwarf gene (dw) on the expression of the muscular dystrophy gene (am) in chicken.

The sex-linked dwarf gene (dw) was introduced into companion muscular dystrophic (am) and nondystrophic (Am+) New Hampshire chicken lines to investigate influences of the dwarf gene on breast muscle weights, muscle fiber area, and the histological expression of muscular dystrophy. Dystrophic and nondystrophic chickens within dwarf or nondwarf genotypes were similar in body and carcass weights. Pectoralis and supracoracoideus muscle weights (as a percentage of adjusted carcass weight) were similar in nondystrophic dwarf and nondwarf males and females. In addition, pectoralis weight was similar in dystrophic dwarf males and dystrophic nondwarf males and females. However, pectoralis weight was significantly smaller in dystrophic dwarf females than in dystrophic nondwarf females, whereas supracoracoideus weight was significantly larger in dystrophic dwarf males than in dystrophic nondwarf males. Supracoracoideus weight was similar in dystrophic dwarf males and females and dystrophic nondwarf females. Pectoralis muscle fiber area was influenced by sex and by dwarf and dystrophy genotype. Muscle fiber area was larger in females than in males, smaller in dwarfs than in nondwarfs, and smaller in dystrophic than in nondystrophic muscles. Muscle fiber degeneration and adipose infiltration was more extensive in dystrophic than in nondystrophic females and males, and it was more advanced in dwarfs than in nondwarfs. Excessive acetylcholinesterase staining patterns were characteristic of dystrophic muscle in both dwarf and nondwarf genotypes. Nondystrophic and dystrophic dwarf male and female chickens are comparable substitutes for nondwarfs as biomedical models with respect to pectoralis histology, acetylcholinesterase staining pattern, and pectoralis muscle hypertrophy.     

Pachytene pairing in relation to sperm and oocyte numbers in a male-fertile reciprocal translocation in the mouse

In adult males carrying the male-fertile reciprocal translocation T(2;4)13H, body weights, testis weights, and sperm counts were higher in heterozygotes than in homozygotes. Heterozygotes whose mothers were C3H/He exceeded their reciprocal counterparts in the same criteria. At 3-4 days of age, no significant differences between homozygous and heterozygous females were found in body weight, ovarian volume, or oocyte numbers, although mean oocyte volumes were somewhat larger in heterozygotes than in homozygotes. In homozygous males and females the synaptonemal complexes of rearranged chromosomes appeared as bivalents that were indistinguishable from normal bivalents. In most gametocytes of heterozygotes, the translocation was present in the form of a quadrivalent. The degree of pairing failure was greater in oocytes than in spermatocytes. Terminal asynapsis of quadrivalents was very rare in spermatocytes, but it affected one quarter of the oocytes. Only very few translocation configurations were associated with the XY bivalent. It is concluded that the number of sperm produced in male heterozygotes can match the general increase in vigor by the formation of a high level of fully paired quadrivalents, whereas a greater degree of terminal asynapsis in the quadrivalents of oocytes may indicate a slightly more deleterious effect of this translocation on oogenesis.     

The relationship between body and gonadal weights of the dusky leaf monkey (Presbytis obscura)

Data from 25 male and 44 female free-ranging dusky leaf monkeys, Presbytis obscura,are analyzed. In a male the mean total testicular weight, 5.82 g, represents 0.078% of the mean adult body weight, 7.39 kg. The mean total ovarian weight, 0.52 g, represents 0.008% of the mean female adult body weight, 6.47 kg. A moderate degree of sexual dimorphism thus exists in this species, female body weight representing 88% that of the male. No seasonal variation in the adult body weight or total gonadal weight of either sex occurs. Only in males is there a strong positive correlation between left and right gonadal weight, and no correlation exists between the total gonadal weight and the estimated age of either male or female adults. Among adults, only females evince a significant positive correlation between total gonadal weight and body weight. No marked change in total ovarian weight occurs during the menstrual cycle, pregnancy, or lactation.     

Sexual dimorphism and ontogenetic allometry of soft tissues in Rattus norvegicus.

Most studies of sexual dimorphism in mammals focus on overall body size. However, relatively little is known about the differences in growth trajectories that produce dimorphism in organ and muscle size. We weighed six organs and four muscles in Rattus norvegicus to determine what heterochronic and allometric scaling differences exist between the sexes. This cross-sectional growth study included 113 males and 109 females with ages ranging from birth to 200 days of age. All muscle and organ weights were ultimately greater in males than in females, because males grew for a longer period of time, had a greater maximum rate of growth, and spent more time near the maximum rate. No ontogenetic scaling differences existed between the sexes in organ weight except for lungs and gonads. During growth, organ weights were negatively allometric to body weight. No scaling differences relative to body weight existed between the sexes for muscles; however, there was variation in the allometric relations among muscles relative to body weight. Sexual dimorphism in muscles and organs appears to be a size difference resulting from differences in the duration and rates of growth.     

Effets de la consanguinité sur des caractères morphologiques quantitatifs chez Culex pipiens autogenicus Roub.

The influence of inbreeding on several morphological characters as proboscis, wings, leg and palp segments was examined in strictly inbred lines of C. pipiens autogenicus, starting with females from a natural population. The results show the importance of ccological conditions, especially temperature, during larval development of the population. We report a progressive average size reduction from the second inbred generation. The length variability increases in practically all cases, depending on the degree of inbreeding, which is often more marked in certain organs. The symmetry regulation is strongly affected. We observe highly significant individual values in the highly inbred generations. The distribution values clearly mark a left/right disturbance. The progression of asymmetry as a function of the degree of inbreeding is more marked in certain organs in the two sexes. The results show the importance of the advantage of heterozygotes.     

Quantitative studies on the regeneration of myelinated nerve fibers. I. Variations in the number and the size of myelinated fibers in the nerves of normal rats]

The number and size of myelinated nerve fibers have been determined at standard levels in the nerve to medial head of right and left gastrocnemius muscles of 24 normal rats (11 males and 13 females). The mean values of all results were comparable on right and left sides. Thus, 271 +/- 5 myelinated nerve fibers were found in the right nerve and 272 +/- 4 in the left; their mean diameter were respectively 8.1 +/- 0.1 and 8.0 +/- 0.1 micron. There were 60.1% of large nerve fibers on the right side and 59,9% on the left, their mean diameters being 10.5 and 10.6 micron. Some variations occured in all these values, depending of the weight and sex of the animals. Nevertheless, the differences between both sides of a same rat were negligible and the histograms of both nerves could be superposed. Accordingly, in the operated animals, the contralateral nerve may be used as control.     

Variability of hematocrit value, blood serum beta- and gamma-globulin level and body weight in different transferrin genotypes of common vole (Microtus arvalis, Pallas 1779) from natural population

1. Heterozygotes TfF/TfE of voles did not differ in body weight, they had higher hematocrit value (males and females), higher beta-globulin fraction (males) or higher gamma-globulin fraction (females). 2. A smaller variability of parameters studied was observed in heterozygotes than in homozygotes. Small and similar variability occurred in hematocrit value and beta-globulins while higher variability occurred in body weight and gamma-globulins. 3. In common voles the faster migrating E system of transferrin may have a higher capacity for iron transport than the F system. 4. Seasonal changes of hematocrit value in vole populations seems to result from genetical and physiological variability. 5. Sexual and seasonal changes in beta-globulin level appear to be related to changes in sexual activity of the animals during the seasons. 6. In autumn, low weight of animals and high serum gamma-globulin level, with the same physiological variability of these two parameters, suggest the synthesis of gamma-globulins with tissue (muscle) proteins. 7. Autumnal increase of gamma-globulin level seems to be very important, taking into consideration the role of the protein in water retention and its filtration from the tissues. Very high level of the protein fraction may play a role in winter high mortality of voles.     

Influence of age on sperm production and testicular weights in men

Age-related changes in daily sperm production (DSP) and testicular weights were investigated in paired testes from 89 men aged 21-50 years and 43 men aged 51-80 years. For both DSP/testis and DSP/g parenchyma, remarkably large standard deviations exceeded 50% of mean values. However, DSP/g and DSP/testis for both right and left testes were approximately 30% higher in the younger than in the older group (P less than 0.01) and were negatively correlated with age (P less than 0.01) when data from both groups were pooled. Weights of whole testes and of testicular parenchyma were similar in both age groups and were not significantly correlated with age. However, testicular tunic weights were 29% higher in the older group (P less than 0.001) and were positively correlated with age (P less than 0.001). Both testicular tunic weight and the % of total testis occupied by tunic were negatively correlated with DSP/g (P less than 0.01); these correlations were weakened by removing the effect of age. Although total testicular weight and testicular parenchymal weight did not change with age, these values were about 10% lower on the left than on the right (P less than 0.001). In addition to its increase with age, testicular tunic weight was about 8% greater for right than for left testes in all men (P less than 0.001). Although the average size of the testis varied from right to left, DSP/g was similar in paired testes (P = 0.15), and the correlation between right and left DSP/g was high (rho = +0.89, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Muscle function studies in amputated lathyritic rats

This study is presented to compare two methods of evaluating changes in muscle function after amputation of the left leg at the knee. Rats were fed a 50% Lathyrus odoratus diet, which causes exostoses to develop at sites of attachment of certain muscles. The rats were on the experiment for 3, 6, or 9 weeks. Muscles of rats killed at 6 weeks were weighed to determine whether atrophy or hypertrophy had occurred. Sizes of exostoses were evaluated subjectively at each time period. The left adductor longus and quadratus femoris muscles underwent considerable atrophy and their exostoses were smaller than on the right side. The left iliopsoas increased in weight and had the larger exostosis. However, the left pectineus increased in weight but had the smaller exostosis. It is concluded that changes in muscle weights and changes in sizes of exostoses both reflect changes in muscle function, but because the two methods respond by different mechanisms, the results do not always agree.     

The relative lengths and weights of metacarpals and metatarsals in baboons (papio hamadryas)

The lengths and weights of metacarpals and metatarsals were measured in two collections of baboon skeletons-33 animals, all born and raised in the wild, and 60 animals, nearly all born and raised in captivity. For both length and weight, ratios were constructed for all possible pairings of the five bones in each individual hand and foot. The pattern of results was not identical for the two collections, but substantial sex differences existed in both collections for many of the ratios calculated. Nearly all of the large sex differences were in the direction of the length or weight ratio being smaller for males than for females. For the length ratios showing the largest sex differences, those differences were larger for the right hand than for the left, and larger for the left foot than for the right, but this pattern was less evident for the weight ratios. Some length ratios for human fingers show sex differences of the sort seen in the metacarpals and metatarsals of these baboons, and the human differences in relative length exist early in life. The implication is that the marked sex difference in androgen exposure during prenatal development may effect the relative size of the individual bones of the extremities in male and female humans and baboons. The relative sizes of the bones of the hand and foot may provide helpful supplemental information on the relations between species, thus making the study of hand and foot bones in other primates and mammals worthwhile.     

Long-term alcohol exposure prior to conception results in lower fetal body weights

BACKGROUND: It is well known that alcohol consumption during pregnancy can result in lower birth weight babies but many women stop consuming alcohol prior to conception as a part of pregnancy planning. The purpose of this study was to determine whether alcohol consumption prior to conception may also have an effect on fetal development. METHODS: Male and female C57BL/6J mice at 4, 6, or 8 weeks of age received either a single administration of alcohol (3.0 g/kg) via intragastric gavage (IG) each day for at least 60 days, or an isovolumetric IG administration of sterile water. After 60 treatment days, males and females within each age and treatment group were mated overnight. Females continued to receive daily alcohol treatments until conception. Males continued to receive treatments until all females were successfully mated. At conception, females were isolated and left undisturbed. On embryonic day 14, fetus number, size, and weight was determined. RESULTS: Maternal food consumption, body weight at conception, and delay to conception onset did not differ between the two treatment groups or among the three age groups. Fetal body weights did not differ among the three age groups. Fetuses from females treated with alcohol had lower body weights compared to those treated with water. Male treatments did not seem to affect fetal body weight. CONCLUSIONS: Fetal growth and development can be affected by alcohol consumption prior to the time of conception. Alcohol consumption prior to conception is a potential risk factor to fetal outcome and an important consideration for those females planning to have children.     

An empirical approach to characterizing trunk muscle coactivation using simulation input modeling techniques

Accurately describing trunk muscle coactivation is fundamental to quantifying the spine reaction forces that occur during lifting tasks and has been the focus of a great deal of research in the spine biomechanics literature. One limitation of previous approaches has been a lack of consideration given to the variability in these coactivation strategies. The research presented in this paper is an empirical approach to quantifying and modeling trunk muscle coactivation using simulation input modeling techniques. Electromyographic (EMG) data were collected from 28 human subjects as they performed controlled trunk extension exertions. These exertions included isokinetic (10 and 45°/s) and constant acceleration (50°/s/s) trunk extensions in symmetric and asymmetric (30°) postures at two levels of trunk extension moment (30 and 80 Nm). The EMG data were collected from the right and left pairs of the erector spinae, latissimus dorsi, rectus abdominis, external obliques and internal obliques. Each subject performed nine repetitions of each combination of independent variables. The data collected during these trials were used to develop marginal distributions of trunk muscle activity as well as a 10×10 correlation matrix that described how the muscles cooperated to produce these extension torques. These elements were then combined to generate multivariate distributions describing the coactivation of the trunk musculature. An analysis of these distributions revealed that increases in extension moment, extension velocity and sagittal flexion angle created increases in both the mean and the variance of the distributions of the muscular response, while increases in the rate of trunk extension acceleration decreased both the mean and variance of the distributions of activity across all muscles considered. Increases in trunk asymmetry created a decrease in mean of the ipsi–lateral erector spinae and an increase in the mean of all other muscles considered, but there was little change in the variance of these distributions as a function of asymmetry.     

Organ weights and organ:body weight ratios of the African white-tailed rat (Mystromys albicaudatus).

Fifty-three adult female and 51 adult male white-tailed rats (Mystromys albicaudatus) were killed with ether and weighed; the spleen, kidneys, liver, heart, lung, pancreas, brain and gonads were dissected free of adhering tissue and weighted. The mean absolute organ weight and organ:body weight ratios by sex and organ were calculated and compared. The male rats were significantly (p less than or equal to 0.05) heavier. The mean weight of the males was 110.0 +/- 23.8 g versus 82.9 +/- 16.1 g for the females. The absolute weights of the heart, liver and kidneys were significantly (p less than or equal to 0.05) greater for the males. The organ:body weight ratios, except for heart and brain (excluding ovary and testicle), were unaffected by sex. The heart to body weight ratio and the brain to body weight ratio were significantly (p less than or equal to 0.05) larger in female rats.     

The relationship between organ weights and body weights, facial dimensions, and dental dimensions in a population of olive baboons (Papio cynocephalus anubis)

Questions concerned with the relationship between organ weights and body weight on an intraspecific level are best answered by using a sample of animals collected in the wild from a single locale during a single season. The organ weights and body weights for this study were obtained from the necropsy reports prepared in the field (Athi Plain, Kenya) by H. C. McGill, Jr. on 36 adult animals (18 males and 18 females). Dental and facial measurements were taken by M.I. Siegel. In order to avoid erroneous results produced by statistical treatment of combined sex samples of sexually dimorphic species, data on the sexes were analyzed separately. Means and standard deviations are reported for selected organ weights and body dimensions (heart, lung, liver, spleen, kidney, adrenal, brain, and pancreas weights, crown–rump length, crown–heel length, head circumference, chest circumference, and body weight). All of the above measures were significantly (p<0.05) different between the sexes. Logarithms of these measures were significantly correlated with the logarithm of body weight in males for heart, lung, liver, spleen, kidney, and adrenal weights, crown–heel length, and head and chest circumference, and in females for crown–heel length, heart, liver, and kidney weights. Partial correlational analysis, removing the effects of body size (weight), showed mostly negative correlational relationships between dental and visceral dimensions. Most of the correlations between facial and visceral dimensions were negative. Allometric equations were calculated for the dental, facial, and visceral dimensions versus body weight, and are compared with prior published results.     

Anatomical differences involving the archicortex and the neocortex of male and female brains: A quantitative syudy of 20 brains of each sex

The relative sizes of the brain stem, cerebellum, diencephalon, archicertex and neocortex were investigated in twenty brains of each sex, by determining the percentages of average total brain weights in each case. The differences between the left and the right cortical regions were also compared. The neo-archicortical ratio was found to be smaller in females than in males. Significantly heavier right neocortex occurred in males than in females. Weight predominance of the right archicortex was found in both sexes. These findings are suggestive that anatomical differences may contribute to the behaviour pattern differences occurring between male and female.     

Seasonal variation in sonic muscles in the fawn cusk-eel Lepophidium profundorum

The fawn cusk-eel Lepophidium profundorum (Ophidiidae) has an unusual sound-producing system with sexually dimorphic sets of antagonistic muscles. Outside the mating season, the dorsal and ventral muscles are well developed and larger in males than in females, but the tiny intermediate muscles are smaller, suggesting a minor role, if any, in male advertisement call production. We examined summer individuals with more developed gonads and find a fourfold hypertrophy of the intermediate but not the other muscles. This result suggests androgen dependence and an important role in sound production for the intermediate muscle. Even though both sexes gain weight in the summer, the ventral and dorsal muscles in females lose weight, suggesting that sound production is less important in females and that muscle mass may be used to support egg growth.     

Lateral asymmetry of kidney weights in different populations of wild mice

Weights of right and left kidneys were compared in different populations of wild mice. Samples were taken from Great Britain, Pacific islands and Sub-Antarctica. The different population samples were further subdivided according to sex and age as estimated by tooth category (i.e., degree of development or wear of upper molars). The mean weights of right kidneys exceeded those on the left in all 28 Subsamples but the data suggested mat this difference decreased with age. The evidence further suggested that the asymmetry between the two kidneys was greater in populations of small mice from the Pacific islands than in those of large mice from Britain and Sub-Antarctica. On the basis of published data on rats and guinea pigs the question is raised whether interspecific differences in kidney asymmetry may be explicable by differences in the sizes of the kidneys in different species.     

Exercise induced increases in muscle fiber number

The effect of weight-lifting, which induced muscular enlargement, on fiber number was tested in the flexor carpi radialis muscle by operantly conditioning 6 cats to flex their right wrist against increasing resistance for an average of 101 weeks. The left was used as a control. At the end of training, the cats were performing "one-arm" lifts with an average of 57% of their body weight. There was an 11% greater muscle weight (P less than 0.01) and 9% (P less than 0.02) more fibers in the exercised muscles from the right limb than in the left. This study using a different method, supports our earlier observations that prolonged weight-lifting exercise significantly increases the total number of muscle fibers.     

Gender differences in effects of 20 days horizontal bed rest on muscle strength in young subjects

Gender differences in the effect of 20 days bed rest (BR) on muscle strength were evaluated in voluntary 11 male and 7 female students. Maximum Isometric Voluntary Contractions (MVC) of 4 right arm muscles (RAM), 5 right leg muscles (RLM), and 2 body trunk muscles were measured with an isometric dynamometer, respectively. Muscle masses (MM) of right arm and leg and body trunk were determined by dual energy X-ray absorptiometry, respectively. The maximum cross sectional area (CSAmax) of right m. quadriceps femoris was measured by magnetic resonance imaging. Elbow flexion MVC in males and all MVC of RLM except knee flexion in both males and females were decreased (p<0.05), but elbow extension MVC in females was increased (p<0.05), while all of other MVC only tended to decrease. However, the decrements in leg MVC were not correlated to the leg MM, and also the decrement in knee extension was not correlated to the CSAmax of m. quadriceps. The reduction of MVC of antigravity muscles might be caused not only by a decrease in MM but also by other factors. The greater decrements of leg MVC during BR were the higher initial level in males, but the inverse was observed in females. However, this discrepancy between males and females cannot be explained in the present study.     

Body weights of wild chimpanzees (Pan troglodytes schweinfurthii) of the Mahale Mountains National Park, Tanzania

Ten male and nine female habituated chimpanzees (Pan troglodytes schweinfurthii) in the Kasoje area of the Mahale Mountains National Park, Tanzania, were weighed intermittently between December 1973 and March 1980 by luring them up a rope hung on a spring balance: six adult males averaged 42.0 kg and eight adult females 35.2 kg. Seasonal change in body weight was recognized at least partially; body weights tended to decrease in the later part of the wet season presumably because of food shortage in the middle of the wet season. Comparison of body weight among three populations of the same subspecies suggests that adult female chimpanzees of Mahale appear to be heavier than those of the Gombe National Park, Tanzania, and that they seem to be similar to the forest-living counterparts of eastern Zaire. On the other hand, body weights of adult male chimpanzees from the three populations do not show significant differences. Perhaps feeding competition among adult females in a small, isolated habitat is more severe than that among adult males, which may result in the body weight reduction among adult female chimpanzees at Gombe.