Morphometric variation of the skull during postnatal development in the Lowland European bisonBison bonasus bonasus

We studied the variation of linear measurements and skull capacity in Lowland European bisonBison bonasus bonasus (Linnaeus, 1758) during postnatal development, and the dependencies of the parameters in relation to sex, age, and body mass of the animals. Material consisted of 599 bison skulls (310 males and 289 females), within the age range of 1 month to 21 years (males) and to 27 years (females). In the group of calves to 1 year old, no sex connected differences in skull measurements were observed, whereas the skull capacity in older calves was significantly larger (0.01>p>0.001) in males than in females. From the third year of life, most skull measurements display characteristics of sexual dimorphism. Skull development in both sexes is most intensive during the first three years of life, and slows from the age of 5. In older individuals of both sexes (≥ 6 years), orbital breadth continues growing and, in females, breadth of splanchnocranium continues increasing. Growth in a bison’s skull capacity is most intensive up to the third year of life and slows from the age of 5. During postnatal development, a bison skull grows proportionally except the neurocranium, which grows slightly slower in comparison with basal length and its development finishes earlier than that of splanchnocranium. In ontogenesis, a bison skull grows much slower compared to body mass. In relation to body mass, skull capacity and the height of neurocranium grow most slowly while orbital breadth grows most intensively. The results obtained were compared with data on skull sizes of bison born in 1930–1950 and bred in captivity and with skulls of the American bisonBison bison. Inbreeding is probably responsible for some types of phenotypic abnormalities in the skull which appear in modern European bison.     

Thymic control of secretory antibody responses in the rat.

The effect of neonatal thymectomy on salivary and serum antibody responses was studied in rats. Local immunization of thymectomized rats with a T-dependent antigen (DNPBGG) elicited negligible amounts of IgA anti-DNP antibody in saliva. In contrast, both normal and sham-thymectomized animals demonstrated substantial levels of salivary IgA antibody. All thymectomized rats locally injected with a T-independent antigen (DNP-Lys-Ficoll) exhibited salivary IgA antibody production. Salivary IgG antibodies were somewhat decreased in thymectomized rats injected with either antigen; however, the final effect of T cell deprivation on IgG synthesis was not as pronounced as on IgA synthesis. Serum IgA antibody was induced in control rats injected with DNPBGG, whereas this Ig class of antibody was absent in thymectomized rats. The results suggest that thymus-derived cells exert a regulatory influence on both serum and secretory IgA responses to antigens.     

Modulation by neonatal thymectomy of the reproductive axis in male and female rats during development

The effects of neonatal thymectomy, at 3 days of age, on parameters of the reproductive axis were examined in male and female Sprague-Dawley rats. Gonadal and accessory sex tissue (male: epididymis, seminal vesicle, and ventral prostate; female: uterus) weights as well as anterior pituitary, spleen, and adrenal weights were determined in the thymectomized and sham-thymectomized animals at 20, 30, 40, 50, 60, and 90 days of age. Plasma gonadotropin concentrations as well as pituitary content of the gonadotropins and prolactin were assessed at each of these time intervals. No significant difference in gonad and accessory sex tissue weights was detected in thymectomized versus sham-operated controls at each of these times. Adrenal weights were increased in thymectomized animals compared with controls at 50 days of age and older in male rats and at 90 days in females. Spleen weights were decreased in the thymectomized males at 50 and 60 days of age. Thymectomy did not affect the spleen weight of females. Plasma concentrations of gonadotropins were unaffected in thymectomized males but were altered in females during the pre- and peripubertal period (Days 20-40). Vaginal opening, however, occurred at the same time in the thymectomized and control females. Pituitary gonadotropin and prolactin content were unaffected by thymectomy of the females, except at 90 days when pituitary luteinizing hormone (LH) content was lower in thymectomized than in control animals. LH and prolactin content were significantly reduced in the males at 60 and 90 days of age. These results demonstrate that there are sexual differences in the effects of thymectomy on parameters of the reproductive axis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Bacterial translocation from the gastrointestinal tracts of thymectomized mice

The incidence of translocation of viable indigenous bacteria from the gastrointestinal tract to the mesenteric lymph node, spleen, liver, and kidney was compared in neonatally thymectomized mice and sham-thymectomized specific pathogen-free mice. The immunologic responses of the thymectomized mice to sheep erythrocytes were decreased compared to the responses of sham-thymectomized mice. Strictly anaerobic bacteria were isolated from only 1.8% of the organs from thymectomized mice and from none of the organs of shamthymectomized mice. Aerobic or facultatively anaerobic bacteria were cultured from 27.4% of the organs of thymectomized mice. Of the thymectomized mice, 70.7% contained viable aerobic or facultatively anaerobic bacteria in one or more of their organs tested, compared with only 10% of the sham-thymectomized mice.Escherichia coli was the predominant bacterial species isolated from these organs, althoughStaphylococcus aureus, Streptococcus, andCorynebacterium also were present.Bacteroides were the only strictly anaerobic bacteria cultured. Neonatal thymectomy promotes the translocation of certain indigenous bacteria from the gastrointestinal tract to the mesenteric lymph node, spleen, liver, and kidney.     

Roentgen cephalometric studies on skull development in rats. II. Normal and hypophysectomized males; sex differences

Growth of the skull in normal male rats of the Long-Evans strain has been studied by serial roentgen cephalometry (under anesthesia) from 27 to 280 days of age, and has been compared with the retardation following hypophysectomy and with growth data obtained on females in an earlier similar study. The dimensions measured represented major skull regions and segments, and in some instances allowed calculation of indices (e.g., neurocranial width/length ratio) which would show changing proportions. In general, the skull showed the more rapid and prolonged growth characteristic of male rats' skeletal development when compared with that of females. Viscerocranial (“facial”) length and width were notable in this respect. On the other hand, growth in neurocranial width and height ceased at a time and size much like that in females. Examination of the possibility that the adult female skull might correspond closely to that of an immature male disclosed that though this might be true for the neurocranium, facial dimensions showed distinctive sex differences. After hypophysectomy at 27 days of age males (as also females) showed marked reduction of growth but not complete cessation. Dimensional increases were between one-fifth and one-fourth of the normal gains. The ratios computed showed that the proportions of infancy were retained after early hypophysectomy.     

Idiopathic paraproteinemia. III. Increased frequency of paraproteinemia in thymectomized aging C57BL/KaLwRij and CBA/BrARij mice

The influence of thymectomy on the appearance of idiopathic paraproteinemia (IP) during aging was investigated in mice of the C57BL/KaLwRij and the CBA/BrARij strains, which under normal conditions develop IP in high and low frequency, respectively. Compared with sham-thymectomized mice, C57BL mice thymectomized at a young adult age showed a markedly increased frequency and an earlier onset of IP during aging; this was even more pronounced in neonatally thymectomized mice. A similar effect of thymectomy was also observed in mice of the CBA strain. Restriction in the heterogeneity of the serum immunoglobulins and the appearance of transient homogeneous Ig components was another frequent finding and this often preceded the appearance of IP in mice of both strains. Thymectomy did not substantially influence either the incidence of paraproteinemias due to a B cell malignancy or the isotype distribution among the paraproteins produced. The results are compatible with the hypothesis that IP develops in three stages as a consequence of an age-related immunnodeficiency that primarily affects the T immune system.     

Measurements of postnatal growth of the skull of Pan troglodytes verus using lateral cephalograms

The postnatal growth of the viscerocranium in relation to the neurocranium of Pan troglodytes verus has been investigated using standardized lateral cephalograms. Sex and age were determined on the basis of cranial morphology and the skulls were divided into four age groups: infantile, juvenile, subadult and adult. The cephalograms were traced on transparencies and specific anatomical landmarks were identified for the measurement of lines angles and the area of the neurocranium and viscerocranium. The results showed that the skull of Pan troglodytes verus exhibits klinorhynchy. During postnatal growth it develops towards airorhynchy, but never shows true airorhynchy. In the infantile age group the measured area of the neurocranium is larger than that of the viscerocranium. The measured area of the viscerocranium increases until adulthood and is larger than that of the neurocranium in the subadult and adult group. From the results we conclude that in Pan troglodytes verus growth of the neurocranium seizes early in juvenile individuals, whereas the viscerocranium grows until adulthood. This may reflect an adaptation to the masticatory system.     

Effects of the anabolic steroid nandrolone phenylpropionate on craniofacial growth in rats

Primary testosterone and its derivatives are anabolic steroids used in the treatment of osteoporosis and Turner syndrome. They also enhance fast-twitch muscle weight in female rats. The present study examines the effect of an anabolic steroid on craniofacial growth and development in rats. Five-week-old female Sprague-Dawley rats (125) were divided into experimental and control groups. The experimental group was injected subcutaneously with 1 mg nandrolone phenylpropionate in the interscapular region on alternate days, whereas those in the control group were injected with a vehicle, arachis oil. Rats were sacrificed at 60 and 120 days of age. Cephalometric analysis of soft X-ray cephalograms showed that chronic administration of the anabolic steroid, nandrolone phenylpropionate, resulted in: (1) about a 20% increase in body weight, (2) an increase in total skull length, (3) elongation of the maxillary and mandibular incisors, (4) an increase in the depth of the antegonial notch, and (5) downward-forward growth of the viscerocranium against the neurocranium. These results suggest that nandrolone phenylpropionate may accelerate craniofacial growth and/or induce high functional activity of the masticatory muscles in female rats. © 1994 Wiley-Liss, Inc.     

鲂鱼的头骨发育及其适应意义

本文对鲂鱼（Ｍｅｇａｌｏｂｒａｍａｓｋｏｌｋｏｖｉｉ）头骨的早期发育过程及其与鱼苗的存活功能需要之间的关系进行了研究。头骨发育的全过程可划分为５个阶段,即软颅阶段、咽颅膜骨附加阶段、脑颅开始骨化阶段、脑颅快速骨化阶段和骨化完成阶段。刚出膜仔鱼头部即有软骨存在,最先出现的硬骨是膜质上颌骨和主鳃盖骨,脑颅最先开始骨化的是基枕骨和侧枕骨,随后才是副蝶骨。头骨发育过程与鱼苗早期存活的功能需要之间有着密切的关系。     

The influence of experimental deformation on craniofacial development in rats

Cranial deformation was produced experimentally in rats 8 to 40 days old for the purpose of studying the rotation of the craniofacial bones and the modification of the growth rates of the functional cranial components. One hundred and twenty four skulls (65 males and 59 females) were employed, classified as: deformed , deformed-hydrocephalic, sham-operated and controls. A midsagittal diagram was drawn for each skull and the angle subtended by each bone with respect to the vestibular plane was measured. Growth indices were worked out for both the neural skull and the facial skull. Deformation altered the rotation of the parietal, interparietal and basisphenoidal bones and restricted the rotation of the fronto-ethmo-facial complex. Alteration of the longitudinal growth rates of the dorsal and basilar components of the neurocranium and the splanchnocranium produced the persistence of the klinorynchal state.     

Changes in skull components of the squirrel monkey evoked by growth and nutrition: an experimental study

Twenty weanling 6-month-old male squirrel monkeys were allotted to the following treatments: 1) first control animals were killed at weaning; 2) second control animals were killed when 24 months old; and 3) malnourished animals were fed on a low-protein diet and killed at age 24 months. Lateral and vertical teleradiographies were taken. Growth of the neurocranial and splanchnocranial components were measured by volumetric (size estimators) and morphometric (shape estimators) indices. All facial components grew. The neurocranial components showed a heterogeneous behavior: The anteroneural component remained stable, and the increase of the midneural component was compensated by a decrease in the posteroneural component. Malnutrition affected the growths of 1) the craniofacial complex, 2) the splanchnocranium, and 3) the respiratory and midneural components. Growth influenced skull shape through 1) increases of the splanchnocranium and the midneural component relative to the neurocranium; 2) decreases of the masticatory and optic components relative to the splanchnocranium, and 3) decreases of the anteroneural and posteroneural components relative to the neurocranium. Malnutrition influenced skull shape through the relationship between the anteroneural component and the neurocranium. These results confirmed the existence of functional interrelationships among the cranial components. A new approach to craniological studies is suggested.     

Early development of the skull of Sander lucioperca (L.) (Teleostei: Percidae) relating to growth and mortality

The early osteological development of the skull (chondrocranium and osteocranium) of the pikeperch Sander lucioperca was studied. Specimens were reared at two temperatures, 15·5 and 18·0° C, from hatching until 47 and 43 days after fertilization (DAF), respectively. The skeletal elements characteristic for the different developmental stages were the same at both rearing temperatures, but pikeperch reared at 15·5° C reached the developmental stages later. The formation of the functional complexes, the neurocranium, jaws and suspensorium, branchial basket and hyoid arch, was evaluated chronologically. The focus was on skull development during several functional changes: at hatching, at the shift from endogenous to mixed feeding, the shift to exclusively exogenous feeding and upon reaching the final prey-capture mechanism. Growth in total length differed between fishes reared at the two temperatures, except during a phase of very slow growth from the end of the embryonic stage until the second larval stage. The latter phase, in which most of the bony elements of the viscerocranium started to form, was marked by high mortality. When exogenous feeding began, the growth rates at both temperatures increased distinctly and the first bony elements were formed in the neurocranium. Specimens reared at 18·0° C grew continuously, but those at 15·5° C showed a second period of slow growth and high mortality. Fish reared at 18·0° C reached the successive larval stages distinctly earlier than fish reared at 15·5° C.     

Metamorphosis of cranial design in tiger salamanders (Ambystoma tigrinum): A morphometric analysis of ontogenetic change

While ontogenetic analyses of skull development have contributed to our understanding of phylogenetic patterns in vertebrates, there are few studies of taxa that undergo a relatively discrete and rapid change in morphology during development (metamorphosis). Morphological changes occurring in the head at metamorphosis in tiger salamanders (Ambystoma tigrinum) were quantified by a morphometric analysis of cranial osteology and myology to document patterns of change during metamorphosis. We employed a cross-sectional analysis using a sample of larvae just prior to metamorphosis and a sample of transformed individuals just after metamorphosis, as well as larvae undergoing metamorphosis. There were no differences in external size of the head among the larval and transformed samples. The hyobranchial apparatus showed many dramatic changes at metamorphosis, including shortening of ceratobranchial 1 and the basibranchial. The subarcualis rectus muscle increased greatly in length at metamorphosis, as did hypobranchial length and internasal distance. A truss analysis of dorsal skull shape showed that at metamorphosis the snout becomes wider, the maxillary and squamosal triangles rotate posteromedially, and the neurocranium shortens (while maintaining its width), resulting in an overall decrease in skull length at metamorphosis. These morphometric differences are interpreted in light of recent data on the functional morphology of feeding in salamanders. Morphological reorganization of the hyobranchial apparatus and shape changes in the skull are related to the acquisition of a novel terrestrial feeding mode (tongue projection) at metamorphosis. Metamorphic changes (both internal and external) that can be used to judge metamorphic condition are discussed.     

Roentgencephalometric study of cranial interrelations

Lateral X-ray films of the skull obtained in 50 normal adult males were used for studies of correlations between 26 characteristics of the size, shape, and position of the face and nine characteristics of the neurocranium in all mutual combinations. The results disclosed that the relations between individual cranial components were regulated by certain principles. The correlations between size dimensions were mostly slight; a closer relationship showed some characteristics of the shape and position. The most important variable exerting an effect on the configuration of the skull as a whole represented the angle of the cranial base which produced the rotation of the neurocranium and the face and thus acted on a series of other correlations. Of some importance as well was the length of the mandibular ramus acting on the shape and position of the lower jaw and on the vertical maxillomandibular relations. The close relationship between the anteroposterior position of both jaws was due to compensation mechanisms rather than to the identical size of both jaws. On normalization of the disturbed saggital jaw relations, the dentoalveolar components of both jaws as well as the subalveolar component of the mandible participated equally. In vertical direction the lower face showed a certain developmental independence. The discussed interrelations formed the basis for studies of the mechanisms regulating the intracranial development and the changes occurring in various anomalies, as well as for understanding the compensation and adaptation abilities of individual cranial components.     

Diachronic variation in cranial thickness of Near Eastern populations

Cephalometric radiographs were taken of 111 skulls of skeletal remains of populations living in Israel and Jordan during the last 12,000 years. From these radiographs, skull length and height, and cranial thickness were measured. For each sex and period, high correlations were found between cranial thickness at vertex, bregma, and lambda. Cranial thickness at nasion was correlated with sinus width but not sinus height. All measurements were correlated with skull length but not skull breadth. Using multivariate analysis, no significant differences in cranial thickness were found between the sexes. Significant diachronic trends were found in lambda and sinus width, and they were independent of variation in skull length.     

Age-dependent expression of cytochrome P-450s in rat liver

Age-related changes in the levels of multiple forms of cytochrome P-450 as well as in the testosterone hydroxylation activities of hepatic microsomes of male and female rats of different ages from 1 week to 104 weeks (24 months) were investigated. The total cytochrome P-450 measured photometrically did not change much with age in either male and female rats. Testosterone 2 alpha-, 2 beta-, 6 beta-, 15 alpha-, 16 beta-hydroxylation activities of male rats were much higher than those in female rats and were induced developmentally. These activities in male rats declined with aging to the very low level in female rats by 104 weeks of age. Testosterone 7 alpha-hydroxylation activity was maximum at 3 weeks of age in rats of both sexes. The levels of individual cytochrome P-450s were measured by immunoblotting. P450IA1 and IA2 (3-methylcholanthrene-inducible forms) and P450IIB1 and IIB2 (phenobarbital-inducible forms) were detected at low levels in rats of both sexes at all ages. P450IIA2, IIC11 and IVA2 were detected in male rats only and were induced developmentally. These male-specific forms disappeared in male rat liver at 104 weeks of age. P450IIC12, a typical female-specific form, was induced developmentally in female rats and was also detected in male rats at 3 and 104 weeks of age. P450IIIA2 (testosterone 6 beta-hydroxylase) was induced developmentally in male rats, but disappeared when the rats were 104 weeks of age. In female rats, P450IIIA2 was detected only at 1 and 3 weeks of age. P450IIA1, IIC6, IIE1 and IVA3 were detected in rats of both sexes at any age. P450IIC6 and IVA3 were induced developmentally and detected at a similar level in rats of both sexes. The level of P450IIA1 was maximum at 3 weeks of age in rats of both sexes. The changes in the level of P450IIE1 during aging were small compared with the changes in other cytochrome P-450s used in this study. These observations provide concrete evidence to our earlier hypothesis that each of the forms of cytochrome P-450 in male rats alter with aging in different patterns resulting in a practical feminization of over-all cytochrome P-450 composition at old age.     

Timing of ontogenetic changes of two cranial regions in Sotalia guianensis (Delphinidae)

Despite the fact that heterochronic processes seem to be an important process determining morphological evolution of the delphinid skull, previous workers have not found allometric scaling as relevant factor in the differentiation within the genus Sotalia. Here we analyzed the skull ontogeny of the estuarine dolphin S. guianensis and investigate differential growth and shape changes of two cranial regions – the neurocranium and the face – in order to evaluate the relevance of cranial compartmentalization on the ontogeny of this structure. Our results show that, even though both cranial regions stop growing at adulthood, the face has higher initial growth rates than the neurocranium. The rate of shape changes is also different for both regions, with the face showing a initially higher, but rapidly decreasing rate of change, while the neurocranium shows a slow decreasing rate, leading to persistent and localized shape changes throughout adult life, a pattern that could be related to epigenetic regional factors. The pattern of ontogenetic shape change described here is similar to those described for other groups of Delphinidae and also match intra and interspecific variation found within the family, suggesting that mosaic heterochrony could be an important factor in the morphological evolution of this group.     

The immunotropism of sunflower oil and starch in peroral administration to mice]

It has been shown that per os introduction of sunflower oil and starch to adult thymectomized mice resulted in reconstitution of the number of Thy-I+ spleen cells similar of the glutamic acid effect. Glutamic acid restored the immune response to sheep red blood cells (SRBC), however, sunflower oil and starch were not effective. The influence of these compounds on the immune response to SRBC in normal and sham-thymectomized mice was different: glutamic acid stimulated it, starch had no influence on the immune response, sunflower oil suppressed it.     

Age-dependent exression of cytochrome P-450s in rat liver

Age-related changes in the levels of multiple forms of cytochrome P-450 as well as in the testosterone hydroxylation activities of hepatic microsomes of male and female rats of different ages from 1 week to 104 weeks (24 months) were investigated. The total cytochrome P-450 measured photometrically did not change much with age in either male and female rats. Testosterone 2α-, 2β-, 15α-, 16α-, and 16β-hydroxylation activities of male rats were much higher than those in female rats and were induced developmentally. These activities in male rats declined with aging to the very low level in female rats by 104 weeks of age. Testosterone 7α-hydroxylation activity was maximum at 3 weeks of age in rats of both sexes. The levels of individual cytochrome P-450s were measured by immunoblotting. P450IA1 and IA2 (3-methylcholanthrene-inducible forms) and P450IIB1 and IIB2 (phenobarbital-inducible form) were detected at low levels in rats of both sexes at all ages. P450IIA2, IIC11 and IVA2 were detected in male rats only and were induced developmentally. These male-specific forms disappeared in male rat liver at 104 weeks of age. P450IIC12, a typical female-specific form, was induced developmentally in female rats and was also detected in male rats at 3 and 104 weeks of age. P450IIIA2 (testosterone 6β-hydroxylase) was induced developmentally in male rats, but disappeared when the rats were 104 weeks of age. In female rats, P450IIIA2 was detected only at 1 and 3 weeks of age. P450IIA1, IIC6, IIE1 and IVA3 were detected in rats of both sexes at any age. P450IIC6 and IVA3 were induced developmentally and detected at a similar level in rats of both sexes. The level of P450IIA1 was maximum at 3 weeks of age in rats of both sexes. The changes in the level of P450IIE1 during aging were small compared with the changes in other cytochrome P-450s used in this study. These observations provide concrete evidence to our earlier hypothesis that each of the forms of cytochrome P-450 in male rats alter with aging in different patterns resulting in a practical feminization of over-all cytochrome P-450 composition at old age.     

Effect of Chemical Thymectomy on Skin Homografts: A Preliminary Report

In an attempt to combine the results obtained by Miller (mice thymectomized at birth accepted homograft at six weeks of age) and those obtained by Selye (selective calcification of the cortex of the thymus with calciphylaxis), calcification of the thymus was produced by the combined injection of dihydrotachysterol and triamcinolone, in non-inbred Sprague-Dawley and hooded, eight-week-old rats. Six days after the beginning of treatment, full-thickness skin homografts were performed on the rats.Homografts exchanged between two rats with complete calcification of the thymus cortex were accepted for an extended period of time, which in the oldest rats at the time of writing was seven months. Homografts exchanged between rats with incomplete calcification of the thymus resulted in a prolonged homograft survival with final rejection within a period of three weeks. Homografts exchanged between rats that were not treated, surgically thymectomized at the same age as the treated animals, or treated with only one of the two substances used for thymus calcification, resulted in rejection in the average time of eight days.