The development of the thoracic duct lymphangions in the prenatal period of human ontogeny]

This paper concerns structural and functional organization of the human lymphatic system during the prenatal period. For the first time the data is presented on the development of thoracic duct based on the concept of lymphangion as a structural and functional unit of a lymphatic vessel. The formation of the duct is considered in connection with structural changes of its wall and variants of duct roots fusion. The following stages are distinguished in the development of the thoracic duct: valval segment stage, protolymphangion, and lymphangion.     

Synapses of the human brain in early prenatal ontogeny

Synaptogenesis in presumptive cerebral cortex was studied in 7-8 week human embryos by electron microscopy. The first synapses in the regions studied appeared in 7-week embryos. These synapses were detected only in the marginal zone of the developing human cerebral cortex, where they were localized on the somas and processes of the young Cajal-Retzius' neurons. A functional role of early embryonic synaptogenesis in the developing human cerebral cortex is suggested.     

Sex dimorphism in the thyroid gland. IV. Cytologic aspects of sex dimorphism in the rat thyroid gland

This study was designed to explain whether the sex-dependent differences in the structure of the thyroid gland of adult male and female rats depend on quantitative or qualitative changes in the thyroid follicular cells. Absolute thyroid gland weight was similar in male and female rats, but its relative weight was markedly higher in females however. Volume fractions of epithelium and stroma were higher and that of colloid lower in male than in female rats and the epithelium/colloid ratio was higher in the males. Also absolute the volumes (in mm3) of epithelium and stroma were higher in the males; the thyroid gland of females contained more colloid. The average volume of a thyroid follicular cell, estimated by stereology, was higher in males than in females, although the thyroid gland contained similar numbers of follicular cells in both sexes. Also, thyroid glands from both male and female rats contained a similar DNA quantity. Results of the present study show that the sex dimorphism in the rat thyroid depends upon a difference in the mean volume of thyroid follicular cells, with males having larger cells than females. However, in both sexes the thyroid gland contains a similar quantity of these cells.     

Development of the neural apparatus of the human pancreas in prenatal ontogeny

In human embryos, prefetuses and fetuses from 6 to 40 weeks of development 82 preparations of the pancreas have been studied; 39 series of slices of the human embryos have been impregnated after Bielschowsky-Boeke. For the first time the nerves grow into the pancreas anlage in embryos of 16 mm long (6 weeks). The main sources supplying the pancreas with the nerves in the period studied are nervus vagus, celiac, hepatic, splenic, right adrenal, superior mesenteric and intermesenteric plexuses. Three stages in formation of the innervational apparatus of the pancreas are distinguished during the intrauterine development. The first stage is characterized by beginning of the nerve growing into the pancreas anlage. For the second stage an increased development of the intraorganic innervational apparatus and appearance of the all main sources of the organ's innervation are specific. The third stage is characterized with an increased differentiation of receptor zones in various parts of the pancreas. The development of the pancreatic innervational apparatus by the time of birth is not completed.     

Sex differences of functional lateralization in the perception of verbal and emotional information in ontogeny

Experimental data show certain differences between men and women in perception of verbal and emotional information. They are revealed in the ability of correct perception of definite kind of information, in the degree of brain functional asymmetry in perception of the given information, in prevalence of domination type. The character of sex differences in functional asymmetry changes little with the age; quantitative correlations of the coefficient of asymmetry diminish with the age.     

Scent-marking in the tamarin, Saguinus oedipus: Sex differences and ontogeny

Many mammalian species which exhibit scent-marking behaviour show a pronounced sexual dimorphism in marking behaviour and scent gland morphology. However, several species of marmosets and tamarins do not show dimorphism in these traits. We examined sex differences in scent-marking structures and behaviour in cotton-top tamarins (Saguinus o. oedipus; Primates: Callitrichidae). While body size and weight were virtually identical in adult males and females, there were pronounced sex differences in scent gland size and in rates of marking behaviour. Females possessed larger anogenital and suprapubic glands and showed 10-fold higher rates of anogenital marking and slightly higher rates of suprapubic marking than males. Observations on the development of anogenital marking revealed a lack of dimorphism during the first 2 years. Adult rates of anogenital marking in females were only observed in females housed separately from their natal family group. The onset of adult levels of marking behaviour corresponds with the adoption of the role of a breeding adult female, suggesting that anogenital marking plays a role in sexual communication.     

Gangliosides of human thyroid gland

The ganglioside composition of adult human thyroid gland was examined in autopsy material obtained from patients who died of circulatory diseases but who showed no signs of thyroid disorders. The concentrations of phospholipids, cholesterol and gangliosides (lipid-bound sialic acid) in the whole glands were 5.2, 4.3 and 0.12 mmol/kg fresh tissue weight and, in dissected follicular material, 7.0, 3.4 and 0.24 mmol/kg tissue, respectively. The molar ratio of phospholipids/cholesterol/gangliosides in the follicular material was 1.00:0.49:0.034. Twelve molecular species of gangliosides were isolated and identified. Gangliosides GM3 and GD3 were most abundant, but GD1a, GD1b, GT1b and 3'-LM1 were also present in quantities greater than 5% of the total gangliosides. N-Acetylneuraminic acid and an alkali labile sialic acid, probably N-acetyl-9-O-acetylneuraminic acid, were found to occur in human thyroid.     

Morphometric studies on the development of human thyroid gland in early fetal life.

Histological and morphometric studies were performed on 30 thyroid glands obtained from normal human fetuses. Their crown-rump length (CRL) ranged from 57 to 190 mm, corresponding to the gestational age of 10-20 weeks. The weight of the thyroid gland increased proportionally in relation to CRL, foot length and fetus weight. The first follicles containing PAS-positive colloid were observed in the peripheral part of the thyroid gland of 57 mm CRL fetus. The number of follicles per 1 mm2 of thyroid surface section increased up to 85 mm CRL and thereafter gradually declined for the end of studied period of fetal life. The volumes (in mm3) of thyroid epithelium, colloid and stroma, beginning from 85 mm increased proportionally to the CRL while the height of epithelial cells did not change. The epithelium/colloid ratio decreased notably to 165 mm CRL and thereafter remained constant. Results of the present study suggest that the thyroid gland of human fetus approaches structural maturity in 17.5 week of gestation.     

Mixed follicles of the human thyroid gland

Mixed follicles are structures composed of squamous-like and follicular epithelia. Little attention has been generally paid to these peculiar follicles of the human thyroid; thus the aim of the present study was to investigate their prevalence and biological properties by means of systematic autopsy, histochemical and immunohistochemical surveys. Mixed follicles were found to be present in 54% and 81% of the patients with solid cell nests, as well as in 50% and 77% of the total number of the ultimobranchial nests, when one or two histological samples from each solid cell nest were examined, respectively. The follicular lumen of mixed follicles usually contained an eosinophilic and PAS-positive colloid-like material, although in 22% of the cases acid mucins sometimes intermixed with PAS-positive granular material and cell debris were also present within lumina. Follicular cells lining mixed follicles basically did not stain positively for calcitonin. The results indicate that mixed follicles are not rarely found in the human thyroid. The presence of intraluminal mucins and cell debris and the absence of calcitonin-containing cells in the follicular epithelium lining these peculiar follicles suggest that at least some thyroid follicular cells could originate from ultimobranchial tissue.     

Sex differences in the chemical composition of uropygial gland waxes in domestic ducks

Sexual differences in the chemical composition of the uropygial gland waxes in domestic ducks have been detected before the nesting period. 3-Hydroxy fatty acids containing diester waxes and significant differences in the composition of the fatty acid and alcohol moieties of the monoester waxes occur during February–June only in the female preen wax. Males as well as ducklings, however, show constant wax patterns. Moreover, no significant influence on wax composition of testosterone or estradiol, respectively in male or female ducklings could be verified.     

Sex dimorphism in the thyroid gland. I. Morphometric studies on the thyroid gland of intact adult male and female rats

Morphometric studies were performed on thyroid glands of intact adult male and female rats. Thyroid follicular cells are markedly higher in the male rats than in the females during estrus. The volume fraction of the epithelium is larger but the fraction of colloid is less in males than in females. Also epithelium/colloid ratio is higher in male than in female rats.     

Selenium concentrations in the human thyroid gland.

Recently, we found that prediagnostic serum selenium concentration was significantly lower for cases developing thyroid cancer (n = 43) than for controls. We assumed that redistribution of serum selenium into the affected tissue took place in the prediagnostic period. The present study was carried out to determine the physiological concentration of selenium in the thyroid, since very few data are available in the literature. The concentrations of selenium in the thyroid (n = 45) and liver samples from Norwegians who had died because of acute illness or accidents were determined by hydride generation atomic absorption spectrometry. The mean selenium concentration was found to be 0.72 +/- 0.44 microgram/g in the thyroid and 0.45 +/- 0.11 microgram/g in the liver tissue. The surprisingly high concentration of selenium in apparently normal thyroids indicates that selenium has important functions in this organ. The remarkably broad range, together with the observation that no significant correlation exists between thyroid and liver concentrations, suggest that factors other than the selenium status are important determinants for the selenium concentration in the thyroid gland. This observation is consistent with our hypothesis that in carcinogenesis, prediagnostic processes influence the serum-/thyroid-ratio of selenium.     

Development of the ductule system of the epididymis in the prenatal period of human ontogeny

In 285 human embryos, prefetuses, fetuses and newborns by means of a complex of morphological methods, development of the epididymal canalicular system has been studied. The anlage of the epididymal canalicular system is stated to appear in embryos 13.0-17.0 mm long (the 6th week of development) and is presented as an accumulation of epithelial cells and primary germ cells between reducing glomeruli and mesonephric canaliculi. The canalization process of the cellular accumulations and their transformation into real canaliculi takes place during the first half of the prefetal period (the 8th week of development). Further growth and development of the epididymal canaliculi takes place in the craniocaudal direction and by the end of the prefetal period (the 12th week) the canaliculi of the head are already formed, they have a twisted course; within the limits of the body and tail they are yet poorly differentiated and their course is nearly straight. During the fetal period of ontogenesis, further differentiation of the epididymal parts occurs and structure of their canaliculi becomes more complex. They acquire a twisted course in all the parts of the organ; by the end of the fetal period the form and structure of the epididymal canaliculi resemble those of the definitive organ.     

Sex differences in the growth of the human bony pelvis

The study of individual patterns of longitudinal growth of the bony pelvic complex reveals the following findings concerning the sex differences in the growth of the bony pelvis. (1) The patterns of growth show the same individual variability and male-female overlap as the adult configuration of pelves. (2) The sex differences in the adult bony pelvis cannot be attributed to the differential response of one bone to sex hormone. (3) Sex differences develop from complicated variations in rates and direction of growth of local areas of the pelvic complex. (4) The superior functional division of the bony pelvis shows only one notable sex difference — the sexual dimorphism of the directional growth of the anterior one-half of the iliac crest. (5) The inferior functional division of the bony pelvis shows numerous local areas of sexually dimorphic growth, but the major sex differences result from the greater lateral migration of the ischia. (6) Of the regions showing definite sexual dimorphism in growth, the pelvic inlet and sciatic notch are the more variable because of their dependency on two separate anatomical systems for their final adult morphological configuration. The subpubic angle and length of the superior pubic ramus are directly associated with only one anatomical system, the enlargement of the pelvic cavity, thus, they show less variability and more definitive sex difference.     

Sex differences in infant rhesus macaque separation-rejection vocalizations and effects of prenatal androgens

Infant and juvenile rhesus macaques exhibit many sexually dimorphic behaviors, including rough and tumble play, mounting, and time spent with nonmother females. This study investigated sex differences in infant rhesus monkey separation-rejection vocalizations (SRVs), and the effects of altering the prenatal hormone environment on these differences. Pregnant females received exogenous androgen (testosterone enanthate), an androgen antagonist (flutamide), or vehicle injections for 30 or 35 days during the second (early) or third (late) trimester of pregnancy. Control females used a greater percentage of coos and arched screams than did control males. In contrast, males used a greater percentage of geckers and noisy screams than did females. Females also had longer SRV bouts, used more calls, and used more types of vocalizations than did males. Mothers were more likely to respond to the SRVs of male infants than to the SRVs of female infants. Prenatal flutamide treatment early in gestation reduced the likelihood that mothers would respond to their male offspring, but prenatal androgen treatment had no effect on response rates of mothers to female offspring. Early, but not late, androgen treatment produced females who vocalized in a male-typical manner. Similarly, early flutamide treatment produced males who displayed more female-typical SRVs. Late flutamide treatments of females produced as much masculinization of SRVs as did early androgen treatment in females. These results demonstrate sex differences in highly emotional vocalizations in infant rhesus macaques and provide evidence that the timing and form of prenatal hormonal exposure influence such vocalizations.