bluuebunny/crossref_metadata_2025 huggingface dataset:
Observations on twin baboon embryos (Papio sp.)
Authors: Hendrickx Andrew G. , Houston Marshall L. , Kraemer Duane C.
Published: February 2005

Twin 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

The 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

The 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

Electron 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

The 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

Neuromuscular 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

Although 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

A 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

In 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.
Neurosecretory material in the supraoptico‐hypophyseal tract of the bat throughout the hibernating and summer periods
Authors: Troyer J. Robert
Published: February 2005

Neurosecretory material in the supraoptico‐hypophyseal tract of 151 hibernating and summer bats (Myotis lucifugus lucifugus) was studied in chromealum‐hematoxylin‐phloxine‐stained serial sagittal sections. Seasonal variations of neurosecretory content throughout the hibernating period (mid‐September through mid‐May) and “active” summer period (June to mid‐September) were observed and the staining density of the neurosecretory material in the supraoptic nucleus, infundibular stem and pars nervosa was “quantitated” visually. Cell counts and measurements also were made to determine if cell number and size changes accompanied seasonal changes in neurosecretory content.

A significantly greater staining density of neurosecretory material in the supraoptico‐hypophyseal tract of the hibernating bats, than in the “active” animals was observed. These differences were always greater in the infundibular stem than in the supraoptic nucleus and pars nervosa. Although there was no correlation between seasonal activity and the total number of neurosecretory cells in each brain, there was always a smaller number of dark‐staining cells in the “active” bats than in those that were hibernating. Nucleocytoplasmic ratios of hibernating bats were below those of the active animals. These resulted from smaller nuclear and larger cytoplasmic sizes during hibernation than in the summer. Nucleolar sizes, however, were slightly greater in the hibernating bats than in the active animals. The significance of these results in terms of seasonal activity is discussed.
Interference with early pregnancy in rats by estrogen: Mechanism of action of dienestrol
Authors: Harper M. J. K.
Published: February 2005

Rats were given single doses of an orally‐active estrogen by mouth on days 1–5 of pregnancy. Examination of uteri on day 8 for implantations revealed that the median effective doses for preventing 50% of the eggs shed from implanting were 0.047, 0.050, 0.035, 0.145 and 0.380 mg/kg for days 1, 2, 3, 4 and 5 respectively. It was found that failure of pregnancy after treatment with the minimal 100% effective dose (ED100) on days 1, 2 or 3 was due to expulsion of eggs from the reproductive tract by day 5. Treatment of rats with the ED100 on day 4 caused expulsion of some eggs from the tract by day 5, but also had effects on the uterus: the position of the blastocysts within the lumen was abnormal and their orientation relative to the mesometrial‐anti‐mesometrial axis disturbed. No decidual reaction was observed on day 6 in such rats or on day 9 in pseudopregnant rats treated similarly and subjected to uterine traumatization on day 5. Treatment with ED100 on day 5 had no effect on egg transport or on the positioning of blastocysts within the lumen on day 6. A decidual reaction was seen around the blastocyst on day 6, but in pseudopregnant rats treated similarly and subjected to uterine traumatization on day 5 no decidual reaction was found on day 9. The pontamine blue reaction was negative in nearly all rats dosed on day 4 and examined on days 6–8. In rats dosed on day 5, however, the blue reaction was negative on day 6, but positive on day 7, i.e., delayed by 24 hours compared to controls and appearing later than the decidual reaction. The blastocysts were unattached in these rats on day 6, but may have attached briefly on day 7 (suggested by the positive blue reaction) and subsequently failed to develop further owing to disappearance of the decidual tissue.
Solitary neurons in human tongue
Authors: Chu C. H. U.
Published: February 2005

Many solitary neurons, each encapsuled by a number of satellite cells and surrounded by collagenic fibers and unaccompanied by other nerve cells, are observed in specimens of the posterior third of the human tongue. They are ganglion cells of the parasympathetic nervous system supplying postganglionic fibers that are adenomotor to von Ebner's gland and myomotor to the smooth muscle of blood vessels. The occurence of solitary neurons suggests that a “ganglion” may consist of a single nerve cell. It is emphasized that the lingual branch of the glossopharyngeal nerve supplying the posterior third of the human tongue is not a sensory but a mixed nerve.
Observations on the distribution of intrarenal nervous tissue
Authors: Gosling John A.
Published: February 2005

The distribution of intrarenal nervous tissue in a number of species has been examined using a cholinesterase technique. Particular attention has been paid to the relationships between the renal vessels and their nerves. Nerves were detected alongside the major intrinsic renal vessels and formed nerve networks on the external aspects of the arterial tunicae mediae. In all specimens, afferent arterioles were accompanied by nerves the majority of which terminated near the entrance of cortical afferent arterioles into their respective glomeruli; nerves along juxtamedullary afferent arterioles continued across glomerular hila. Relatively few nerves were demonstrated near cortical efferent arterioles while juxtamedullary efferent vessels possessed a rich innervation. Intramural smooth muscle was identified in juxtamedullary efferent arterioles, aglomerular vessels and arteriolae rectae and these vascular segments were accompanied by nervous tissue. Cholinesterase positive nerves could not be detected in the renal medulla.
Electron microscopic studies on granulocytopoiesis in the slender salamander
Authors: Campbell Ferrell R.
Published: February 2005

The morphology of differentiating heterophils and eosinophils of the slender salamander, Batrachoseps attenuatus, was studied with electron microscopy. Enzymes of the granules of both cell types appear to arise from the Golgi cisternae. An agranular stem cell was not observed and the least differentiated cell type encountered was an “early” promyelocyte having small granules which are morphologically distinct from mature granules of either the heterophil or eosinophil series. Heterophil myelocytes and later stages contain only one population of granule which is fibrous in content. Eosinophils likewise possess but one type of granule; the granules are larger than those of heterophils, have a homogeneous content, and lack the crystallin core so characteristic of mammalian eosinophils.
A quantitative study of the blood vessels of the pig's skin and the influence of environmental temperature
Authors: Ingram D. L. , Weaver M. E.
Published: February 2005

The vascular supply to the skin of pigs was studied in animals perfused with the dye, monastral fast blue. The arrangement of the blood vessels in control animals was in three plexuses, similar to that in other mammals but with the middle plexus poorly developed.

A litter of pigs was divided into two groups at the age of 12 days and one group was raised in a warm room and the other in a cold room. The pigs were killed at age three months when the warm room was 35°C and the cold room 5°C. A quantitative evaluation of the blood supply to the skin of the experimental animals revealed that the pigs from the warm room had more blood vessels in the skin than those raised in the cold; the difference was statistically significant (P < 0.01). In the case of pigs from a second litter reared at 35°C and 20°C, no significant difference in the number of blood vessels was detected.
The evolution and development of the dens of the mammalian axis
Authors: Jenkins Farish A.
Published: February 2005

Certain members of the extinct reptilian group from which mammals evolved possessed both a dens and an atlas body. Available paleontologic evidence supports the conclusion that the dens evolved as an addition to the atlas body. There‐fore, the dens is not homologous with the atlas body as is generally claimed on the basis of supposed developmental evidence. The atlas body is large in the most primitive of living mammals, the monotremes, which also possess a dens of typical mammalian proportions. In metatherian and most eutherian mammals, both a dens and an atlas body remnant of variable size are present. The development of the dens in the Virginia opossum, Didelphis marsupialis, confirms the fact that the dens arises from, but does not replace, the atlas body anlage. The dens evolved as a functional replacement of the atlanto‐axial articular processes which were lost when the mammalian atlanto‐axial joint became specialized for rotational movement.
Photophores of Porichthys notatus: Ultrastructure of innervation
Authors: Strum Judy May
Published: February 2005

Photophores in Porichthys notatus are bioluminescent organs composed of a lens, photogenic tissue, and an underlying reflector. Nerves penetrate through the reflector and branch, free of their Schwann cells, among the photogenic tissue elements. The tortuous pathways of axons have been followed by electron microscopical serial sections. After giving off occasional terminal branches, the axons continue into pockets of connective tissue which penetrate among the photogenic, supportive, and lens cells. There they form tuft‐like clusters of nerve endings, some of which contain dense‐cored vesicles. None of these endings was seen to penetrate the basal lamina and make direct intercellular contact with either a supportive cell or a photogenic cell. From these observations, it is concluded that the nerves end outside of the basal lamina surrounding photogenic, supportive, and lens cells. Adhesion sites, which may indicate chemical synaptic contact, were occasionally observed among these neural components.

The photophores of the California Porichthys notatus often bioluminesce following intraperitoneal injection of the fish with epinephrine. It therefore appears from experimental, anatomical and fine structural evidence, that these luminescent organs are innervated and controlled by the sympathetic nervous system.
The distribution of valves in rat kidney arteries
Authors: Taggart Nancy E. , Rapp John P.
Published: February 2005

Serial sections of rat kidneys were studied for the presence of valves. Intimal valves were found in interlobular arteries at sites where arteriolar branches went directly to juxtamedullary glomeruli. Arteriolar branches to glomeruli which are not juxtamedullary glomeruli did not possess valves at their origins. This location suggests that these valves may be important as regulators of blood flow to the vasa recta spuria which supply the medulla.
Ovarian morphological and functional changes in reproductively senescent hamsters
Authors: Thorneycroft Ian H. , Soderwall A. L.
Published: February 2005

Ovaries from young and senescent hamsters were examined morphologically on days 8, 12 and 14 of pregnancy to determine if there were any differences between the two age groups. The senescent hamsters had fewer follicles present than the young on all days of gestation. The senescent females' corpora lutea experienced the greatest growth between days 8 to 12, whereas corpora lutea from young animals grew the most between days 12 and 14. Corpora lutea in senescent females did not grow at all between days 12 and 14. The lower number of follicles in senescent females was not due to the lower rate of implantation. Superovulation with PMS revealed that the senescent ovary was refractory.

It was concluded that there are quantitative not qualitative differences between ovaries from young and senescent hamsters during pregnancy. The refractory ovary of senescent females could be contributing to pregnancy wastage in this species by secreting less progesterone.
A record of “testis cords” in the ovary of a mature hippopotamus (hippopotamus amphibius, Linn.)
Authors: Clough G.
Published: February 2005

A small patch of immature‐testis‐like tubules is described from the ovary of a sexually mature, fertile hippopotamus. It is compared with similar tubules described in the literature from other species and it is concluded that the tubules are derived either from cords formed in the foetal ovary or are an early granulosa‐cell tumor.
Aortic cartilage in the heart of Syrian hamsters
Authors: Kelsall Margaret A. , Visci Marguerite
Published: February 2005

A C‐shaped bar of hyalin cartilage was present in the fibrous tissue around the aortic orifice in the heart of all 70 male and 10 female Syrian hamsters, 103 to 843 days old. This cartilage has the same cellular and intercellular characteristics as the tracheal cartilages. Fibers from four of the six lunulae of the semilunar aortic valves, the aortic sinuses and vestibule, and cardiac muscle adjacent to the posterior semilunar valve insert onto the fibrous capsule and the protuberances of the aortic cartilage. A few fibers from the ventricular and interatrial septa and the aortic cusp of the mitral valves are also attached to the fibrous capsule. Cartilage did not occur around the pulmonary orifice or in other regions of the heart with the exception of a chondroma in the aortic valve. The C‐shaped aortic cartilage in this hibernating species is discussed in relation to its possible significance in preventing collapse of the aortic orifice and the possibility of increasing coronary blood flow.
The fine structure of the placental villi of the rhesus monkey(Macaca mulatta)
Authors: Luckett W. Patrick
Published: February 2005

Placental villi were obtained from monkeys at the Wisconsin Primate Research Center during 50–150 days gestation. As in the human, the villi consist of a vascular mesenchymal core surrounded by inner cytotrophoblastic and outer syncytiotrophoblastic layers.

The syncytiotrophoblast contains abundant rough endoplasmic reticulum and a well developed Golgi complex consisting of stacked lamellae and diffuse vesicles. An asymmetrical distribution of ribosomes occurs on RER cisternae associated with mitochondria. Branched microvilli frequently bear dilated tips and resemble stereocilia. Cytoplasmic tufts and microvilli increase the surface area, and the base of the tuft usually contains a large membrane‐bound vacuole with a flocculent inclusion of low electron density. These vacuoles are lacking after 100 days. In later stages the syncytiotrophoblast bears irregular microvillous processes and specialized attachment sites at its contact with the basal lamina.

Hofbauer cells in the villus core contain numerous large vacuoles, coated pinocytotic vesicles and smooth vesicles apparently derived from ER; the latter are sometimes fused to the large vacuoles. Hofbauer cells appear to be derived from undifferentiated mesenchymal cells.
The relationship of cartilage canals to the initial osteogenesis of secondary centers of ossification
Authors: Wilsman Norman J. , Van Sickle David C.
Published: February 2005

Initial osteogenesis of secondary centers of ossification in the humeral head of the dog was studied with serial sections, histochemistry, radiography and vascular injections. At birth this chondroepiphysis was found to be well vascularized by a network of cartilage canals. On the second day after birth the first morphological evidence of the secondary center of ossification was seen. This was in the form of multiple foci of calcification. Each focus of calcification occurred immediately adjacent to the glomerular end of a cartilage canal and not in an avascular matrix. The capillaries of the glomerulus were modified in the process and persisted as the blood supply to the secondary center of ossification. By four days of age the individual foci had coalesced into a single larger focus of calcification. This process of ossification was found to possess morphological similarities to that occurring at the metaphyseal side of the epiphyseal plate.
Pulmonary veins in the chick embryo: Origin as determined by radioautographic mapping
Authors: Rosenquist Glenn C.
Published: February 2005

In the head process to early head fold stage chick embryo, the cells which will form the pulmonary veins are located in the mesoderm near the posteromedial edges of the heart‐forming regions. At the 26 somite to early limb bud stage, the presumptive pulmonary vein cells have been folded to the midline of the embryo as part of the splanchnic mesoderm and form the endothelial plexus which courses through the dorsal mesentery of the sinoatrial region of the heart.
Spermatogonial stem‐cell renewal in the mouse
Authors: Oakberg E. F.
Published: February 2005

Type A spermatogonia in the mouse can be separated into five successive classes on the basis of nuclear morphology and stage of the cycle in which they occur. Enumeration of all types throughout the cycle of the seminiferous epithelium reveals that the As spermatogonia are the stem cells. They divide throughout the cycle and, especially at stages IX to I, form chains of cells which then give rise to spermatogonia A1 at stages II–VIII. The A1 cells divide in IX to form the A2, which divide in XI to form A3, and the A3 cells divide in I to form the class A4 spermatogonia. Spermatogonia A4 give rise only to the In type; there is no evidence for the formation of either As or A1 from A4 spermatogonia. Repeated injections of 3H‐thymidine and tracing the history of labeled cells to 15 days after labeling supported the conclusion obtained from morphological and numerical data that As spermatogonia are the stem cells of the testis.
Popliteus muscle in man
Authors: Lovejoy John F. , Harden Thomas P.
Published: February 2005

This paper describes the morphology of the popliteus muscle based on the dissection of 15 human cadaver's knees. The muscle is found to have three origins: the strongest from the lateral femoral condyle is already wellknown, but there is also an important band from the fibula and a firm attachment to the posterior horn of the lateral meniscus. The femoral and fibular origins form the arms of an oblique Y‐shaped ligament, the base of which is formed by the capsule and the meniscal origins. This previously was described as a separate entity, the “arcuate ligament,” attached to the belly of the muscle, but it is not a separate ligament. Rather it is a condensation of the fibers of origin of the popliteus including those from the fibula.
The relationship between the pubo‐urethral ligaments and the urogenital diaphragm in the human female
Authors: Milley Paul S. , Nichols David H.
Published: February 2005

The connective tissue supports of the human female urethra have been investigated in 14 cadavers and 20 fetuses. In all cases the urethra was found to be suspended from the pubic bone by bilaterally symmetrical anterior, posterior and intermediate pubo‐urethral ligaments. The anterior and posterior ligaments were formed by reflections of the inferior and superior fascial layers of the urogenital diaphragm. The intermediate ligament represented a fusion of these fascial layers and no transverse perineal ligament was found.

It is suggested that the term pubovesical ligament is a misnomer since this band of connective tissue passes from the pubic bone to the urethra and not to the bladder. It is thus analogous to the puboprostatic ligament of the male. An anatomical defect in the pubo‐urethral ligaments might be a contributing factor to urinary stress incontinence in the female.
Vascular morphology in hypertensive states in the rat
Authors: Friedman Sydney M. , Scott Gordon H. , Nakashima Miyoshi
Published: February 2005

The morphological characteristics of the tail artery and of the superficial epigastric neurovascular bundle, fast‐frozen in vivo with a cryosurgical probe in less than one second, were examined in norepinephrine and in deoxycorticosterone acetate (DOCA)‐induced systemic hypertension. Acute vasoconstriction produced by norepinephrine begins in the innermost muscle layers and extends by degrees to the outer layers. The pull of the inner cells is distributed through the wall by a network of radially disposed collagen fibers. No qualitative signs of vasoconstriction were observed either in arteries or arterioles in advanced DOCA hypertension. Here, the pattern was dominated by hypertrophy, apparent in the size of the smooth muscle cells and of their nuclei and in a considerable accentuation of cell boundaries indicating an increase in the paracellular matrix.
The survival and differentiation of embryonic lung tissues in diffusion chambers and in mammary fat pads of mice
Authors: Andrews Edwin J.
Published: February 2005

The culturing of lung tissues in diffusion chambers in vivo has failed to support epithelial elements. The transplantation of lung rudiments into mammary fat pads of mice, however, has allowed long term culture (11 months) with complete differentiation of the explants.
Electron microscopy of granule release in metrial gland cells of the pregnant rat
Authors: Larkin Lynn H.
Published: February 2005

The fate of the granulated metrial cell was studied with the electron microscope. In the degenerating areas of the metrial gland the granulated metrial cells undergo necrosis. The granules of the lysed cells are enclosed by a limiting membrane and their contents appear unaltered. The observations indicate that after the granules are free, the limiting membrane is lost and the contents released into the tissue space. Phagocytic cells are apparently involved in clearing the area of cellular debris. Metrial granules are sometimes engulfed by the phagocytic cells. The “lipid bearing” cells of the metrial gland were also investigated with the electron microscope. These cells contained few organelles, a flocculent cytoplasmic ground substance, lipid droplets, and large dense bodies. The membrane limited dense bodies resemble secondary lysosomes and contain multilaminated myelin whorls plus a variety of dense fibrous or homogeneous material. The release of metrial granules is discussed in relation to the possible secretion of relaxin by metrial cells. The role of the lipid bearing cells is also considered.
Volumetric composition of the monkey skeleton
Authors: Gong Joseph K.
Published: February 2005

Five adult monkeys (Macaca mulatta) having an average weight of 3.4 kg were analyzed for the overall skeletal contents of water, fat, nonfatty organic fraction, volatile inorganic fraction and ash. Volumes of bone and marrow for each skeletal region were calculated according to an earlier method used in the study of the dog and rabbit (Gong and Arnold, '65; Gong and Reis, 1970). A shortcut method for calculating marrow volume and fresh volumes of trabecu‐lar and cortical bone using only two variables, the ash volume (or mass) and the fresh volume of the skeletal region, was also shown. It was found that the marrow constituted approximately 50.7% of the overall skeletal volume. Comparison of the composition of the marrow in the long bone and flat bone regions of the skeleton showed that the general distribution of the various components in these regions was similar to those found in the dog and rabbit; namely, a relatively high fat content in the long bone marrow and relatively high nonfatty organic and water contents in the flat bone marrow.
Muscle spindle distribution in snout musculature of the Japanese shrew‐mole
Authors: Kubota Kinziro , Masegi Toshiaki
Published: February 2005

This investigation was designed to provide the structural basis for snout‐mandibular movement of insectivores. Muscle spindle distribution in the snout musculature of six Japanese shrew‐moles was examined in serial cross sections stained with hematoxylin‐eosin and azan.

Zygomaticus major, Levator labii superioris and Zygomaticus minor contain about 120 muscle spindles but Levator alae nasi superioris and inferioris have no spindles. The spindles are concentrated within the lower half of the musculature. The average of the spindle area of one muscle measured was about 0.1 mm2 and the extent the spindles were observed was 11 mm. The ratio of the spindle area to the muscle area was a maximum of 25% in the posterior one‐third of the belly, 10% in the middle and 1% in the anterior.

Since the facial muscles are considered either to be devoid of spindles or few in number, it is of considerable interest that the snout musculature is supplied by abundant muscle spindles. It also suggests that the delicate movements of the snout muscle might be under minute control of the proprioceptive mechanism.
Expansion of placental site and maternal blood supply of primate placentas
Authors: Gruenwald Peter
Published: February 2005

Development of placental site and uteroplacental arteries was studied in Tarsiidae, Ceboidea, Cercopithecoidea, and Hominoidea. In Tarsiidae the placental attachment and single artery remain essentially unchanged from early on, and the placenta grows beyond the original site in the shape of a button. In Tarsiidae and Ceboidea maternal arteries and their branches are incorporated in the placenta and their wall is replaced later by a layer of fibrin, Ceboidea have several arteries in the original placental site; this site is enlarged including additional arteries by ingrowth of villi from the chorion in an area surrounding the original site. Further growth is by centrifugal spread; the basal endometrium is stretched and no new arteries are tapped. In Cercopithecoidea the placenta has a sharp border from early on. Spread with stretching of the underlying endometrium occurs here, too. Additional arteries running in this stretched endometrium are secondarily tapped and increase the total number. The disc of Hominoidea, remaining after formation of the chorion laeve, also stretches the underlying decidua, but then trophoblast pervades much of it until it taps arteries in a much larger area than in the other forms.
Effects of estrogen on the transition zone of the mouse uterine cervix
Authors: Bradley Carolyn F. , Graham Charles E.
Published: February 2005

Histologic changes in the region of the squamocolumnar junction of the uterine cervix in ovariectomized C3H/HeJ mice were studied at 6‐12 hour intervals after the injection of 2.3μg estradiol benzoate. Mitotic activity, especially in the basal layer of stratified squamous epithelium, increased as time elapsed after estrogen administration and produced a concomitant increase in stratification of squamous epithelium; some mitotic activity was present in the uterine columnar epithelium throughout the period of observation. The histologic character of the squamocolumnar junction changed from gradual transition to an abrupt demarcation, as in intact mice during the estrous cycle. Subcolumnar cells in the transition zone of untreated animals formed a unilayered reticulum which after estrogen injection developed into a reticulum of stratified squamous epithelium. Extensions of stratified epithelium which develop during chronic estrogen treatment apparently develop from the stratified reticulum. There was no evidence to indicate any contribution of metaplasia to estrogen‐induced epidermization.
Differences in histochemical attributes between diaphragm and hindleg muscles of the rat
Authors: Yellin Herbert
Published: February 2005

Muscle fibers of the diaphragm and hindleg muscles of the rat were characterized bistochemically by their mitochondrial distribution (succinic dehydrogenase activity) as A, B and C (after Stein and Padykula, '62), by their myofibrillar, alkali‐stabile ATPase activity as α, β and αβ (after Samaha et al., '70), and by their acid‐stabile ATPases (intermyofibrillar and myofibrillar) as D (dark), M (moderate) and L (light). Comparisons of the differentially stained serial sections revealed profound dissimilarities between the fibers of functionally disparate muscles. The majority of fibers of the hindleg muscles were distinguishable as the conjugates AαβM, BβTD and CαL (figs. 1‐3), whereas those of the diaphragm were principally AαM, BαL and CβD (figs. 4‐6). Thus, no one histochemical reaction could accurately predict the multiple attributes of fibers of both muscle groups. Previous studies suggest that additional discrepancies in histochemical appearance would arise were other specialized muscles, e.g., extraocular muscles (Yellin, '69), compared with the more common muscles of body and limb. Any extrapolation of data on the basis of limited histochemical analyses is not without risk, whether comparing the same muscle in different species (Yellin and Guth, '70), or different muscles in the same species.
Proprioceptive afferents in facial nerves of some insectivores
Authors: Kubota Kinziro , Masegi Toshiaki
Published: February 2005

Fiber‐caliber analysis of the facial nerve was made in the Japanese lesser shrew‐mole and the Japanese shrew‐mole possessing muscle spindles in the snout muscles and in the shinto shrew with no spindles. Using an enlarged photographic scale (× 250) prepared from the object‐micrometer (1/100 mm), the measurement of the fiber‐caliber was made on the enlarged photograph (× 1250) of the cross paraffin section treated with a modified myelin‐sheath staining procedure by Pettersen et al. ('70). The facial nerves of the shrew‐moles contained fibres of 1 to 10 μ in diameter, while the facial nerve of the shrew consisted of fibers of 1 to 6 μ The spectra of the former have a slight bimodality with the highest peak at 2 μ and smaller one at 6 μ. The spectrum of the latter has a unimodality with a greater peak at 2 μ. Each peak revealed a log‐normal distribution curve. Statistically, it can be said that there is a significant difference in the caliber‐spectra between the facial nerves supplying the snout muscles with muscle spindles and without spindles.

For testing whether the skew of the spectrum can be the result of a truly bi‐modal distribution, the left facial nerve of the Japanese shrew‐moles was cut at the site beneath the auditory capsule. Complete degeneration of spindle innervation in the snout muscles was observed histologically in animals seven days after operation.
Estrogen‐induced osteoid formation in the osteon of mature female rabbits. An electron‐microscopic study
Authors: Whitsan S. William
Published: February 2005

The osteons of mature female rabbits injected with estradiol valerate, parathyroid extract, or a combination of both were studied. Two, 1 mg injections of estradiol valerate (Delestrogen®) given in a one week period stimulated osteoid production on the inside of the lacunar borders of osteocytes but had little effect on osteoid production along the perimeter of the Haversian canal. Parathyroid hormone induced osteolysis after two weeks of treatments, with little apparent increase in osteoclast numbers. Parathyroid extract treatment for one week followed by estradiol valerate treatment in combination with parathyroid extract treatment the second week induced osteoid formation along both lacunar borders and Haversian canal perimeters. This evidence shows that estrogen can stimulate osteoid production and is not limited to inhibition of bone resorption. Increased osteoid production along the perimeter of the Haversian canal in dual‐treated rabbits implies an interaction between estrogen and parathyroid hormone.
Acid phosphatase distribution in the trigeminal ganglion of the rat
Authors: Peach Roy
Published: February 2005

Localization of acid phosphatase in trigeminal ganglia of vascularly perfused, young, Wistar rats was demonstrated by Gomori's lead sulfide and Barka and Anderson's azo dye methods. Differences in deposition of reaction product, indicating differences in levels of enzyme activity, were demonstrated between small, intensely reactive (dark) neurons and larger, less reactive (light) neurons. Lengthening the fixation time to lessen the likelihood of artifactual origin of such differences resulted in a decreased reaction in all neurons; relative difference in intensity of large and small neurons was retained. The results indicate that the level of detectable acid phosphatase activity is an additional distinguishing feature between light and dark cells in trigeminal ganglia of the rat and suggest that differences between these cells are not artifactual.
Total leydig cell volume and its estimation in dogs and in models of testis
Authors: Kothari L. K. , Srivastava D. K. , Mishra Pushpa , Patni M. K.
Published: February 2005

The total Leydig cell volume has been determined in 40 dog testes using a histometric point‐counting method. In preliminary experiments, the accuracy of the method has been established on specially prepared plasticine models of the testis. The point‐counting method has a mean error of ± 7% and the values obtained by it, when statistically analysed, are not significantly different from those determined by direct measurements (p > 10% ). Thus, work on the models has provided convincing experimental verification of the method.

The Leydig cells constitute about 15% (14.2 to 17.1% ) of the testicular volume in dogs. In absolute terms, it comes out to be 1.56 ± 0.45 ml of Leydig cells per testis. Larger testes contain proportionally greater amount of Leydig cell tissue, the relationship being almost linear. Although very little data is available for comparison, and none perhaps for the dog, it appears from the present study that the total quantity of Leydig cells in this species is essentially the same as in man.

Since it allows a reliable estimate of the total Leydig cell volume directly in milliliters per testis, the point‐counting method has proved to be much more useful than older methods which merely determined the proportion of Leydig cells in relation to some other testicular component.
Ultrastructure of the rat testis after vasectomy
Authors: Flickinger Charles J.
Published: February 2005

The fine structure of the rat testis was studied at intervals of up to nine months after bilateral vasectomy, unilateral vasectomy, or a bilateral sham operation. Objectives were to determine whether the fine structure of the testis is altered as a result of vasectomy and to determine if any of the sperm produced after vasectomy are retained and disposed of within the testis. Attention was directed toward the ultrastructure of developing spermatids, the cytology of Sertoli cells, and the structural relationships between Sertoli cells and germ cells. No alterations in these features were detected, and it was concluded that the fine structure of the rat testis remains normal after vasectomy. Factors are discussed which may qualify this conclusion, such as the structural complexity of developing germ cells and the multiplicity of stages in the cycle of the seminiferous epithelium. Sertoli cells contained residual bodies after vasectomy, but there was no evidence that phagocytosis by Sertoli cells increased, suggesting that the main site of disposal of sperm after vasectomy lies distal to the seminiferous tubules.
Protein uptake by rat preimplantation stages
Authors: Schlafke Sandra , Enders Allen C.
Published: February 2005

The protein tracers, horseradish peroxidase and ferritin, are demonstrable in the subzonal space of all preimplantation stages within ten minutes when incubated in vivo or in vitro. However, there is very little uptake of these proteins by ova and two‐cell stages. By the blastocyst stage there is greatly increased uptake of exogenous protein. The proteins appear in coated micropinocytotic vesicles and tubules, larger vacuoles, and more complex bodies. Blastocysts from the period of lactationally delayed implantation show an even greater amount of uptake, especially in the supranuclear region. Peroxidase reaction product can be demonstrated in the cavity of day 5 blastocysts in 30 minutes, and in the cavity and basal lamina of the blastocysts during delayed implantation in ten minutes. Ferritin was more sparsely distributed, and was not seen in the blastocyst cavity in any of the time periods. Peroxidase is apparently transported via an intracellular pathway, since it is not seen in the elaborate intercellular spaces between trophoblast cells. Acid phosphatase activity is demonstrable in vacuoles, dense bodies and Golgi cisternae in all stages, indicating that the potential for degradation of ooplasm and phagocytized material by a lysosomal system is present in all of the preimplantation stages examined.