bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bony pelvic sexual dimorphism in the rat
Authors: Bernstein P. , Crelin E. S. 
Published: February 2005

AbstractNormal pelvic dimorphism is the result of the male pelvis acquiring morphological features during postnatal development that differ from those of the female. The first dimorphic features appear at 32 days of age. At 76 days of age the male pelvis has eleven dimorphic features that constitute the dimorphism of the normal adult. The development of five of the 11 features is dependent on the presence of the testes, whereas, the other six develop independently of the testes. The testes‐dependent features develop in males castrated at birth and treated with testosterone. The postnatal development of the female‐type pelvis in the normal female is not dependent on the presence of the ovaries.
The projection of optic nerve fibers in the frog Rana catesbeiana as studied by radioautography
Authors: Goldberg Stephen , Kotani Minoru 
Published: February 2005

AbstractTritiated leucine was unilaterally introduced into the vitreous chambers of metamorphosing bullfrog tadpoles in an attempt to determine whether the optic fibers may be traced by radioautography. After injection, the animals were sacrificed at varying time intervals from 4½ minutes to 32 days. Serial sections of the brain were subjected to radioautography. The optic fibers were thereby traced to their known terminations and to a small thalamic cell cluster to which we found no reference in the literature. Significant differential radioactivity was detectable in the contralateral optic lobe as early as six hours postinjection, suggesting a flow, whether intra‐ or extraaxonal, of at least 10–22 mm/day.A single postmetamorphic frog underwent excision of the optic chiasm with positioning of the stumps of the optic nerves against the lateral wall of the thalamus. Fifteen weeks were allowed for regeneration. When the same histologic and radioautographic technique as above was used (sacrificing at eight days postinjection), a grain path was found to extend from the optic nerve into the brain. This path divided into two distinct branches, one branch crossing over and one remaining on the same side. These results indicate the practicality of tracing nerve distribution within the CNS by radioautography.
The canine lymphoid system: A study of the effect of surgical excision
Authors: Chretien Paul B. , Behar Raymond J. , Kohn Zev , Moldovanu Graziella , Miller Daniel G. , Lawrence Walter 
Published: February 2005

AbstractA detailed study of the lymph node anatomy of the dog is presented, and a technique for surgical excision of the thymus, spleen, and all gross lymph nodes is described. The dissections were performed after intravenous administration of pontamine blue to living animals.Major excision of the lymphoid tissue of the dog led to a modest prolongation of skin allograft survival, but it did not lead to a further increase in the allograft prolongation achieved with 6‐mercaptopurine immunosuppression when these two measures were used simultaneously. Neither did lymphadenectomy alter the leucopenia or toxicity of 6‐mercaptopurine when node excision was performed immediately prior to initiation of drug therapy. The transient nature of both the lymphopenia produced and the alteration of allograft response after lymphadenectomy suggest that there is another major contributor to the circulating lymphocyte pool. It is suggested that this may well be the lymphoid tissue in the intestinal wall.The surgical preparation described is proposed as a model for the study of lymphoid tissue depletion and regeneration in the dog.
Influence of exercise and tenectomy on the morphology of a muscle nerve
Authors: Tomanek Robert J. , Tipton Charles M. 
Published: February 2005

AbstractThe effects of decreased and increased levels of muscular activity on the morphology of the medial gastrocnemius nerve were investigated in male albino rats assigned to tenectomy, control and exercise groups. Nerve fiber diameter and the number of constituent myelinated fibers were measures obtained from images of transverse sections projected onto drawing paper.The mean values for the tenectomised animals for nerve fiber diameter (X = 7.41 ± 0.13 μ) and number of nerve fibers (X = 223 ± 5.4) are significantly lower than the means of the control animals (X fiber diameter = 7.96 ± 0.14 μ; X number of fibers = 247 ± 5.2). Associated with these changes is a marked atrophy of the gastrocnemius muscle.A single bout of exercise (running in an activity cage) did not produce changes in nerve fiber diameter (X = 7.58 ± 0.17 μ) nor in the number of nerve fibers (X = 238 + 5.0). Moreover, an eight‐week exercise program consisting of running on a treadmill had no significant effect on mean nerve fiber diameter (X = 8.04 ± 0.18 μ) nor in the number of nerve fibers (X = 231 ± 6.3).Correlations between gastrocnemius muscle weight and mean nerve fiber diameter or number of nerve fibers revealed no significant relationships. It was concluded that only the tenectomy data supported the theory of interdependency of muscle and nerve.
Observations on the abdominal lymphaticovenous communications of the squirrel monkey (Saimiri sciureus)
Authors: Roddenberry Harvey , Allen Lane 
Published: February 2005

AbstractThe abdominal lymphaticovenous communications in the squirrel monkey were studied by injection, sections and by microscopic observations in vivo. Caval pressures were measured and correlated with lymphatic pressures.Lymphaticovenous communications were easily identified by a pulsating reflux of venous blood, which was related more to lymphatic than to venous pressure. The caval venous pressure was constant at 7 cm H2O. Lymph continued to flow until venous pressure reached 14 cm H2O. The first lymphatic valve remained competent at 60 cm H2O. There was no anatomical or physiological evidence of a sphincter mechanism at the lymphaticovenous ostia. With identical criteria, no abdominal lymphaticovenous communications were found in the rat. Except for rare anomalies, abdominal lymphaticovenous communications are species characteristics.
Microradiography of intrapulmonary bronchial veins of the dog
Authors: Reeves John T. 
Published: February 2005

AbstractMicroradiographs of 100‐300 μ slices of dog lungs which had pulmonary veins injected with barium sulphate showed good filling of brochial veins. Bronchial veins joined pulmonary veins at frequent intervals along the longitudinal axis and around the circumference of bronchi. Frequently, pulmonary veins and pulmonary capillaries entered the bronchial venous system, suggesting venous flow from lung to bronchus. Single veins along the margin of small bronchi (1 mm) received both pulmonary venous and bronchial venous blood. Therefore, there was a particularly intimate relationship between pulmonary and bronchial veins. The submucous venous plexus was prominent and was composed of thin‐walled, 50 μ‐diameter veins which had surprisingly direct connections to pulmonary veins. The proximity of a large venous plexus to the airway lumen suggested that oxygen transport could occur, thereby reducing venous admixture of the arterial blood.
Differential collagen stain by an acid fuchsin, iron, flavianic acid mixture. A note on ferrous sulfate hematoxylin
Authors: Lillie R. D. , Gutierrez A. , Palmer R. W. 
Published: February 2005

AbstractSubstitution of flavianic acid (50 mM) or of a stoichiometric mixture of naphthol yellow S and hydrochloric acid, in place of picric acid in Van Gieson type mixtures gives deeper yellow colors to cytoplasm, muscle and erythrocytes. Higher concentrations of acid fuchsin can be used with consequent greater density of collagen fiber staining and improved contrast.The familiar weakening of hematoxylin nuclear stains by exposure to Van Gieson mixtures can be largely avoided by inclusion of 0.1 M ferric chloride in the Van Gieson mixture. Alum hematoxylin can then be used in place of the unstable iron hematoxylin solutions, and the iron hematoxylin effect is attained by the iron postmordanting in the Van Gieson bath. A ten minute prestain in an alum hematoxylin containing 0.5% hematoxylin is adequate but density can be enhanced by longer staining or by staining at higher temperature; 5–10 min at 60°C is suggested. The iron containing flavianic or picric acid Van Gieson staining baths should be restricted to three minutes; longer exposures gradually weaken nuclear staining.Substitution of 0.1 M copper sulfate for the iron in the Van Gieson bath also yields dark gray to black nuclei. Aluminum chloride (0.1 M) has an effect similar to the control hydrochloric acid, while the chromium ion seems quite inferior, even to the control HCl mixture.A ferrous sulfate hematoxylin ripened overnight with a small amount of ferric chloride gives excellent progressive nuclear staining, adequate in 2–5 minutes, and not excessive in 30 minutes. The solution gradually deteriorates in 6–8 weeks.
Morphological studies on the reproductive organs of blinded male hamsters and the effects of pinealectomy or superior cervical ganglionectomy
Authors: Reiter Russel J. 
Published: February 2005

AbstractThe testes, seminal vesicles and coagulating glands of hamsters subjected to bilateral optic enucleation (blinding) involuted within 6–8 weeks. During the first several weeks after blinding there was relatively little change in the weights of the reproductive organs, however, between 4–6 weeks the weights of these organs declined precipitously. Finally, the testes and accessory sex organs of 8‐week blinded hamsters were about one‐tenth and one‐third their normal size, respectively. The atrophic testes exhibited a complete loss of spermatogensis and an apparent diminished secretion of androgens since the seminal vesicles and coagulating glands also regressed significantly. Despite the involution, the testes showed a high degree of deoxyribonucleic acid synthesis as evidenced by the large number of spermatogenic cells which took up tritiated thymidine. These findings indicate that the testes retained a certain level of regenerative capacity even in the presence of advanced tubular damage.If hamsters blinded for 9 weeks, had either their pineal gland or superior cervical ganglia removed, the involuted testes and accessory organs regenerated and returned to the normal size, and presumed function, within approximately 8 weeks. Regenerated testes were histologically indistinguishable from those of normal animals. Eyeless hamsters killed after 17 weeks still possessed involuted reproductive organs.
Extracellular connective tissue fibrils in the chick embryo
Authors: Low Frank N. 
Published: February 2005

AbstractAn electron microscopic study of extracellular connective tissue fibrils in the chick embryo is reported herein. Primary fibrils (40–45 Å) are first to appear, being present in the primordia of ectodermal boundary (basement) membranes in freshly laid eggs. Free microfibrils (40–150 Å) appear by delamination from boundary membranes from 24 hours incubation onward. The notochord becomes intensely active in forming microfibrils toward the end of the second day. By 72 hours free mesenchymal cells are producing microfibrils. Axial periodicity is acquired relatively slowly by microfibrils in their transition to unit collagen fibrils. At one week's incubation fibrillar diameters and periodic banding still do not match the recognized adult pattern.The hypothesis that a single developmental line of fibrils leads to all extracellular connective tissue fibrous elements is supported by the ontogeny of fine structure in the chick. Microfibrils first arise in close association with primary fibrils, then from notochordal cells and later, more directly from free mesodermal cells (mesenchyme, fibroblasts). The collagen, reticular and elastic fibers of light microscopy arise from aggregations and alterations of fibrillar material whose line of descent is traceable to the microfibril.
Observations on twin baboon embryos (Papio sp.)
Authors: Hendrickx Andrew G. , Houston Marshall L. , Kraemer Duane C. 
Published: February 2005

AbstractTwin baboon embryos were acquired by hysterotomy from a multipara on the twenty‐sixth day of gestation. All preceding and succeeding pregnancies yielded single births. This case of dichorionic, diamniotic twins is unique because there is a seven day difference in the morphological development of the two embryos. The embryos are approximately the same fertilization age because mating was limited to one 12 hour period of the menstrual cycle. In addition only one corpus luteum was identified at laparotomy. Both twins were males as indicated by the sex chromatin, eliminating the positive identification of dizygosity. Several alternatives for the twins' origin are cited. One possibility is that there was a division of the blastomeres at the two‐cell stage, or at some other stage before implantation, yielding monozygotic twins. Another possibility is that both ova arose from the same follicle, yielding dizygotic twins. The larger embryo is 2.0 mm in greatest length and has six pairs of somites, and is similar to ten other baboon embryos 25–26 days old. The smaller embryo is of the trilaminar disc stage and is comparable in developmental features to five other baboon embryos 18–19 days old. The morphological features of each placenta are comparable in development to the age of its respective embryo.
The fine structure of sow lutein cells
Authors: Goodman Paul , Latta John S. , Wilson Richard B. , Kadis Barney 
Published: February 2005

AbstractThe morphological observations described in this report are part of a biochemical study of progesterone intermediates using sow ovary. This tissue is extensively involved in the production of some steroid hormones. Because the lutein cells are thought to be involved in the synthesis of progesterone and its intermediates and because these cells constitute by size and number the greatest portion of the mass of sow ovary, we confined the morphological investigation to these cells. Sow corpora lutea, fixed with glutaraldehyde and osmium tetroxide were examined by light and electron microscopy.The lutein cells of the sow are large epithelioid cells with oval nuclei and extensive amounts of cytoplasm. Large masses of highly organized smooth endoplasmic reticulum, many oval mitochondria with tubular cristae, and many lipid droplets are present. Only a few profiles of rough endoplasmic reticulum are seen in any one section, and Golgi membranes cannot by distinguished from other smooth membranes. The smooth endoplasmic reticulum is the major membranous organelle in these luteal cells. Microsomal preparations from luteal cells must be very rich in fragments of these smooth membranes. The demonstration of many steroidogenic enzyme systems in microsomal preparations lends strong support to the supposition that these enzyme systems reside in the smooth endoplasmic reticulum.
Correlation of ovarian abnormalities in young golden Hamsters with blood estrogen content
Authors: Kent Harry A. , Mandel Jeffrey A. 
Published: February 2005

AbstractThe possibility that the incidence of polyovular follicles and multinucleate ova may depend upon hormonal balance, in the hamster, has been investigated with respect to circulating estrogens. Samples were drawn at weekly intervals from the third through the seventh week of age. An inverse correlation was found to exist. Total blood estrogen decreased from day 21 to day 35, then increased through day 49. Polyovular follicles are most numerous at day 35 while multinucleate ova are most numerous on day 42. Non‐polar estrogen decreased from day 21, achieving a low 28 day level which was maintained throughout the study period. More polar estrogens dropped to the thirty‐fifth day and rose by the forty‐ninth day. The limiting factor in the decrease of more active polar estrogens may be lack of conversion of non‐polar to polar estrogens or a tendency toward rapid degradation and loss of polar estrogens. The role of the fluctuating estrogen titres in the development of ovarian abnormalities is discussed.
Size‐dependent distribution of axoplasm, schwann cell cytoplasm, and mitochondria in the peripheral nerve fibers of mouse
Authors: Samorajski T. , Friede Reinhard L. 
Published: February 2005

AbstractElectron micrographs of vagus and sciatic nerve fibers of different size from adult male mice were examined by planimetry to determine the distribution of axoplasm, Schwann cell cytoplasm and mitochondrial density. The findings revealed that the ratio of axoplasm to Schwann cell cytoplasm in normal mature fibers increased with fiber size. The increase appeared curvilinear from 61% axoplasm in nonmyelinated fibers to 90% in the thickest myelinated fibers. Schwann cell cytoplasm extended along the sheaths in longitudinal and interconnected strands. The number of strands varied between 2 and 5, depending on fiber size. An analysis of mitochondrial density in axoplasm and Schwann cell cytoplasm of nonmyelinated and myelinated fibers revealed a greater concentration of mitochondria in the Schwann cells with increasing fiber size. The mean ratio of mitochondrial density between axoplasm and Schwann cell cytoplasm was 1:0.24 for nonmyelinated fibers, 1:2.54 for fibers with less than 30 lamellae and 1:5.21 for fibers with 30 or more lamellae. The distribution of mitochondria observed in electron micrographs was confirmed histochemically by localization of NAD‐diaphorase activity.
Prepubertal and pubertal changes in the hamster ovary
Authors: Greenwald Gilbert S. , Peppler Richard D. 
Published: February 2005

AbstractThe ovary of the newborn hamster is characterized by numerous oogonia which are undergoing mitotic divisions. By day 8, the germ cells have developed into oocytes (dictyate stage). The oocytes and granulosa cells are surrounded by an undeveloped network of fibrous stromal cells until day 14. Between days 14 and 21, the stroma is transformed by hypertrophy and hyperplasia into a primary interstitium consisting of large epithelial cells.The critical period of follicular development is from days 21 to 28, with antral follicles first appearing on day 26. The earliest spontaneous ovulations occur on day 29. This differs from the temporal relationship in the rat and mouse in which antral follicles not only develop several weeks before puberty but can also be induced to ovulate prematurely with exogenous gonadotropins. In contrast, in the hamster the maximal ovulatory response to pregnant mare's serum (PMS) develops rapidly between days 27 to 30. Over this period, induced ovulations increase from an average of 10.5 ova to 55 eggs. The altered responsiveness to PMS does not correlate with any change in the diameter of follicles or number of secondary or tertiary follicles. It is therefore concluded that progressively smaller follicles become competent to respond to exogenous gonadotropin between days 27 and 30.
Muscle spindles in the intrinsic and extrinsic muscles of the Rhesus monkey's (Macaca mulatta) tongue
Authors: Bowman James P. 
Published: February 2005

AbstractNeuromuscular spindles were searched for in the intrinsic and extrinsic muscles of the rhesus monkey's tongue. Transverse, horizontal and parasagittal sections were obtained from the tongues of three animals and stained with the Weigert‐van Gieson technique. The results showed that spindles were distributed in all of the intrinsic muscles as well as in certain of the extrinsic muscles. The potential significance of these findings is discussed in relation to the feedback pattern derived from the lingual spindles in response to tongue activity.
Effects of amputation of limbs and digits of lacertid lizards
Authors: Bellairs A. D'A. , Bryant Susan V. 
Published: February 2005

AbstractAlthough the majority of adult lizards are able to regenerate lost portions of tails, only rarely have instances of limb or digit regeneration been observed. The present work describes the histological features of the stumps of limbs and digits of Lacerta vivipara and Lacerta dugesii at various times after amputation, and compares these features with those which are seen after amputation or autotomy of the tail. The results show that the early stages of healing of the limbs and digits are similar to the early stages of tail regeneration. The epidermis which migrates over the wound becomes thickened, and cells released from dedifferentiating stump tissues accumulate beneath it. In one case, that of a digit, a papilla was seen extending from the wound epidermis into the blastema. During the later stages of healing differences between the events taking place in the limbs and digits, and the tail, become marked. The blastema fails to increase in size, and it appears that most of its cells are converted into a cartilage cap and sleeve investing the cut end of the bone. An investigation has also been made of the regenerative ability of the limbs of embryonic Lacerta vivipara. Limbs were amputated in ovo at various stages of embryonic life, but no cases of regeneration were observed.
Factors influencing fusion of rat palates grown in vitro
Authors: Myers Gordon S. , Petrakis Nicholas L. , Lee Melvin 
Published: February 2005

AbstractA technique is described for growth in vitro of embryonic rat palatal tissue on defined and semi‐defined media. Palatal fusion closely resembling that occurring in vivo is found in these preparations. Fusion occurs in a large number of cases even in the absence of an animal extract. However, development is improved if fetal calf serum is added to the synthetic medium. Using Leibovitz Medium L‐15 with 20% fetal calf serum, complete fusion was obtained in 87% of the palates, partial fusion in 9% and no fusion was found in only 4% of the palates cultured.Incorporation of galactoflavin, a riboflavin antagonist in a riboflavin‐deficient diet of the mother or in the culture medium results in a decreased number of complete fusions and corresponding increase in partial fusions. A suggestion is made as to the manner in which galactoflavin acts in vivo to produce palatal cleft, based on the incidence and type of clefts and the histological appearance of the palatal tissues.A method is described in which the tissue sections are sliced prior to culture so that the behavior of individual palatal shelves can be studied during the fusion process. Fusion occurs between shelves if the medial margins are apposed, regardless of whether the two shelves come from the same embryo, from littermate embryos, or from non‐littermate embryos. Some possibilities for application of this technique are suggested.
Antler growth and osteoporosis II. Gravimetric and chemical changes in the costal compacta during the antler growth cycle
Authors: Banks William J. , Epling Glenwood P. , Kainer Robert A. , Davis Robert W. 
Published: February 2005

AbstractIn an attempt to support the morphological data indicating a cyclic physiological osteoporosis in three three‐year‐old captive Rocky Mountain mule deer, costal cortical biopsy material was analyzed by densitometric and chemical methods. Bone densities, amount of ash per unit volume and levels of calcium, phosphorus and magnesium per unit volume indicated bone mineral was mobilized during periods of antler growth. However, calcium to phosphorus ratios were maintained at normal levels during this reversible cyclic phenomenon. These data substantiated the morphological observation of a cyclic physiological osteoporosis in the mule deer.