bluuebunny/crossref_metadata_2025 huggingface dataset:
Passage of red blood cells through the sinusoidal wall of the spleen
Authors: Cho Yongock , De Bruyn Peter P. H.
Published: February 2005

The migration of blood cells across the wall of splenic sinusoids has been studied by means of serial sections in rats inoculated with murine erythroblastosis virus (MEV). The sinusoidal walls of the normal spleen have no permanent openings. In the normal spleen, mature red blood cells and blood cells in the latest stages of maturation can be seen in diapedesis. The predominant form of transmural migration is intercellular. In MEV‐inoculated animals, in which there is a vigorous erythroblastic proliferation, large numbers of erythroblasts are in transmural passage. Serial sections show that these cells migrate through the cytoplasm of the endothelial lining cells. On the basis of these observations, it is suggested that the transcellular mode of migration may be related to the delivery of newly formed red blood cells into the circulation while the intercellular mode may be part of the mechanism by which the spleen controls the removal of red cells from the circulation.
Anomalous patterns of mammalian oocyte maturation and fertilization
Authors: Thompson Robert S. , Zamboni Luciano
Published: February 2005

This report illustrates some of the errors that may occur during in vivo and in vitro maturation and fertilization of mammalian ova, considers the possible mechanisms accounting for their occurrence, and discusses their functional consequences. Included in the description are anomalies of oocyte and follicular development, i.e., multinucleated oocytes, polyovular follicles, and aberrations of zona pellucida formation. Also considered are deviations from the normal process of oocyte maturation such as chromosomal anomalies, development of abnormal nuclear structures (subnuclei), inhibition of polar body formation and aberrations of polar body structure. Anomalies of the process of fertilization such as polyspermia, sperm penetration into polar bodies, and development of multinucleated blastomeres in two‐cell embryos are also described.
Effect of gonadotropins on ovulation and ovarian histology in the immature mongolian gerbil
Authors: Fischer Theodore V. , Fisher Don Lowell
Published: February 2005

The present study is an analysis of the effects of super‐ovulatory doses of gonadotropins on the rate and time of ovulation and ovarian histology in immature gerbils. Groups were treated with various combinations of pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (HCG). The maximum superovulatory response followed treatment with 10 IU PMSG and 20 IU HCG. High dosages of PMSG inhibited superovulation, as did some combinations involving the highest dose of HCG. Entrapment of ova within corpora lutea was common in groups receiving high doses of either gonadotropin. Luteal regression, appearing by day 3, occurred often in groups receiving high doses of HCG. A dose of 10 IU PMSG and 5 IU HCG resulted in both a near maximal superovulatory response and the least abnormal ovarian alteration.
Presence of cells combining features of two different cell types in the colonic crypts and pyloric glands of the mouse
Authors: Nabeyama A.
Published: February 2005

A small number of epithelial cells which combine features of two cell types were observed in the descending colon and pyloric stomach of the mouse.

In the descending colon, where the base of the crypts is mainly composed of poorly differentiated “vacuolated” cells, a few of these cells contain, besides the characteristic “vacuoles,” mucous globules identical to those in mucous cells or, less frequently, dense granules such as are found in entero‐endocrine cells. Because there is evidence that the poorly differentiated vacuolated cells give rise to the other cells of the epithelium, those which also contain mucous globules or dense granules are likely to be differentiating into mucous cells or enteroendocrine cells respectively.

In the pyloric stomach, where the glands are mainly composed of mucous cells, some of which are poorly differentiated, a few of the latter exhibit, besides the mucous globules, entero‐endocrine type granules or features of caveolated cells. It is likely that the poorly differentiated mucous cells give rise to the other gland cells; and, therefore, those mucus‐containing cells which also display dense granules or caveolated cell features are taken to be differentiating into entero‐endocrine or caveolated cells respectively.

Most of the cells containing two kinds of secretory materials are believed to be stem cells which initially contain a few vacuoles (colon) or mucous globules (pylorus) but are differentiating into a cell containing a different type of secretion. Rare observations of two kinds of secretory materials in a mature cell suggest that the transitional period may be prolonged, perhaps indefinitely.
Phagocytosis of degenerating germ cells by follicle cells in fetal guinea pig ovaries
Authors: McNamara Nancy , Black Virginia H.
Published: February 2005

Virus‐like particles (80 mμ to 100 mμ in diameter) occur in the endoplasmic reticulum of germ cells in the ovaries of fetal guinea pigs, and are confined to this population of cells. Using these particles as a marker, the phagocytosis of degenerating germ cells by somatic cells in the cortex of the ovary was traced.
The genesis of cell types in the adenohypophysis of the human fetus as observed with immunocytochemistry
Authors: Baker Burton L. , Jaffe Robert B.
Published: February 2005

Hypophyses of 21 human fetuses, ranging in gestational age from 6 to 23 weeks, were studied by immunocytochemical and histological staining to ascertain (1) the time of origin of specific cell types and (2) the development of parenchymal cell zonation in the pars distalis. No hormones were identified at six weeks. Probable corticotrophin‐containing cells appeared at seven weeks. Somatotrophs were observed first at 10.5 weeks; correlation with other reports indicates that they appear at eight to nine weeks. Melanotrophs were detected at 14 weeks; the cells containing melanotrophin were far fewer than corticotrophs. The youngest fetus to possess gonadotrophs was 10.5 weeks old. In all specimens gonadotrophs (LH‐cells) stained well with immunocytochemical procedures but poorly with histological methods. Thyrotrophs first occurred at 13 weeks.

Zonal distribution of cell types in the pars distalis was evident almost from the time of their appearance. Somatotrophs were most numerous laterally and immediately anterior to the residual cleft. At 10.5 weeks corticotrophs were confined chiefly to the borders of vascularized connective tissue (trabeculae) and to the lateral peripheral region of the pars distalis. Thyrotrophs appeared chiefly in the anteromedian zone, particularly in its superior portion, but were found laterally also. In the older specimens, gonadotrophs generally occurred throughout the pars distalis but were less numerous near the trabeculae and in the anterolateral region.

There was good correlation between the time of appearance of various cell types and published data on secretory capacity of the gland.
Reproduction of the canyon bat, Pipistrellus hesperus, in Southwestern United States
Authors: Krutzsch Philip H.
Published: February 2005

The reproductive biology of the bat Pipistrellus hesperus was investigated histologically using animals obtained from nature at monthly intervals throughout the year.

The female shows proestrous morphological changes in late summer and autumn, which continue until early spring. Insemination is probably effected several times during proestrous, since both sexes are intermittently active throughout this period (August‐April). Permanent arousal from torpor and return to normal metabolism in the spring results in ovulation. Both ovaries are functional and both uterine horns may be utilized. P. hesperus is monestrous; two young per bat is usual.

The male spermatogenic cycle is initiated in late June and the first sperm are available for ejaculation in September. Some sperm remain in the seminiferous tubules until early March. The epididymides also serve in sperm storage with the caput emptied by late February and the cauda in April. Leydig cells are largely nonsecretory from March through July, a few are secretory in August and most are secretory in September and October. Active cells gradually decline in number until few are secretory in late March.

Accessory sex glands are functionally cyclic: they are small from April through August, hypertrophy in September, and gradually involute to the resting stage through March, to achieve total involution in April.

The penis, similar in structure to that of other vespertilionids, is thought specialized to insure effective insemination.
Quantitative morphology and carbohydrate histochemistry of the mouse submandibular gland following prepubertal castration
Authors: Smith Richard J. , Frommer Jack
Published: February 2005

The endocrinologic basis for morphological and biochemical sex differences in the mouse submandibular gland have not been clarified. Previous studies have emphasized the maintenance of glandular differences in adult animals, rather than considering the factors responsible for their developmental etiology. Male CD‐1 mice were castrated at intervals between 10 and 50 days of age and killed at 100 days. The quantitative development of granular tubules and the carbohydrate histochemistry of the submandibular glands were compared to untreated males and females. The area of granular tubules increased with age at castration. Nested analysis of variance indicated significant differences among treatments and among sections within individual glands. No group of castrated males had a greater development of tubules than untreated females. Carbohydrate histochemistry demonstrated an increase in carboxylated mucosubstances in the acinar cells and granular tubule cells of castrated animals.
Estrogen and antagonist‐induced structural changes in the cervico‐vaginal epithelium of immature rats
Authors: Anderson Winston A. , Kang Yuan H.
Published: February 2005

Estrogen enhances proliferation and keratin formation in the cervico‐vaginal epithelium of immature rats, whereas the estrogen antagonist, CI‐628 (Parke‐Davis), represses mitosis and induces mucinogenesis. Combinations of antagonist and estrogen allow differentiation of an epithelium composed of both keratin‐forming and mucous cells. Both estrogen and antagonist induce synthesis of a cervico‐vaginal endogenous peroxidase in the intermediate and superficial layers of the epithelium. The secreted vaginal mucus of antagonisttreated animals stains intensely for exogenous peroxidase.
Macrophage‐lymphocyte clusters in lymph nodes: A possible substrate for cellular interactions in the immune response
Authors: Farr Andrew G. , De Bruyn Peter P. H.
Published: February 2005

The lumens of the lymphatic sinuses in lymph nodes are traversed by fibrocellular trabeculae. Joined to these trabeculae were macrophages, which formed cell clusters with lymphocytes. It is proposed, based on structural similarities, that these cell clusters are the equivalent in vivo to those seen during primary and secondary immune responses in vitro. These intraluminal macrophages were located in the path of lymph‐borne antigen, as well as in the path of newly formed and recirculating lymphocytes in sinuses. This would facilitate the possible interaction between macrophage‐associated antigen and antigenreactive lymphoid cells. The attachment of numerous lymphocytes to the surfaces of macrophages and the resulting cell clusters aslo afford increased opportunities for lymphocyte‐lymphocyte contact.
Vinblastine‐induced microtubular paracrystals in prolactin cells of anterior pituitary gland of lactating rats
Authors: Shiino Mastaka , Rennels Edward G.
Published: February 2005

Vinblastine sulfate in physiological saline was injected directly into the pituitary glands of lactating rats. Injections were made through the ear canal using a syringe equipped with a 24‐gauge needle. The animals were killed at 2, 4, or 6 hours after the injections. When the anterior pituitary glands were examined by electron microscopy, many microtubular paracrystalline deposits were seen in the prolactin and growth hormone cells. The usual cytoplasmic microtubules and microfilaments were not seen in the cytoplasm of these cells. Granular extrusion (exocytosis) was markedly depressed, and an accumulation of secretory granules was definitely observed in the prolactin cells after the administration of vinblastine.
Presence of multiple centrioles in a rhesus macaque oocyte matured in vitro
Authors: Zamboni Luciano
Published: February 2005

This report demonstrates for the first time the presence of centrioles in a rhesus macaque oocyte which had attained meiotic maturation in culture. The exceptional presence of centrioles in this oocyte was associated with anomalous patterns of chromosomal and spindle organization.
Age‐dependent sensitivity of basal cells in mouse vaginal epithelium towards the differentiating action of estrogen
Authors: Galand Paul , Rognoni Jean‐Baptiste
Published: February 2005

Following ovariectomy, the vaginal epithelium of the mouse is reduced to two layers of cells, the basal layer that constitutes the germinative compartment and a surface layer. Under estrogenic influence, this tissue undergoes keratinization at the expense of basal cells only. The initially superficial cells are progressively sloughed, without taking part in the cornification process. We have shown previously that within the first 12 hours after estrogen administration (that is, before any change in mitotic activity is detected) an intermediate layer of cells is formed. Thus, a migratory process is induced, which leads to a very rapid redistribution of basal cells into two layers. The purpose of the present work was to test whether the sensitivity of basal cells towards this initial differentiating influence of estrogen depends on cellular age. Therefore, ovariectomized animals were injected with 3H‐thymidine, treated with a single injection of 17‐β‐estradiol benzoate (1 μg/animal) at time intervals of 10, 22, 34, 48 or 60 hours, and finally killed 12 hours thereafter. Autoradiography was used to measure the degree of participation of the labeled cells in the formation of the intermediate layer (at 12 hours) as a function of their age at the moment of estradiol injection, as measured by the delay between labeling and estrogen administration. The results indicate that the susceptibility of basal cells to estrogen‐induced migration behavior (at 12 hours) increases more or less exponentially with cellular age.
Establishment of a TSH‐releasing‐hormone‐secreting cell line from the area cerebrovasculosa of an anencephalic foetus
Authors: Ishikawa Hiroshi , Nagayama Takahisa , Kato Chieko , Niizuma Katsuhiko
Published: February 2005

A cell line was established from the area cerebrovasculosa of an anencephalic foetus, five types of cells were identified in this cell line, and medium conditioned by this cell line caused strong TSH‐secreting activity in cultured human pituitary cells.
Postnatal differentiation of leydig cells in the rabbit testis
Authors: Gondos Bernard , Renston Richard H. , Goldstein David A.
Published: February 2005

After the gradual disappearance of fetal Leydig cells in the first week after birth, the interstitial tissue of the rabbit testis is composed principally of undifferentiated mesenchymal cells between one and five weeks of age. Also present during this time are scattered partially differentiated cells with ovalshaped nuclei, prominent nucleoli and abundant cytoplasm. These cells exhibit some of the cytoplasmic features of steroid‐secreting cells, but extensive development of smooth endoplasmic reticulum and the grouped perivascular arrangement characteristic of fully differentiated Leydig cells are not present. The latter features appear at five weeks of age, indicating the formation of mature Leydig cells at that time. By seven weeks, the bulk of the interstitial tissue consists of Leydig cell aggregates, typical of the appearance in adult testis. Since spermatogonial mitoses first appear at seven to eight weeks of age, the findings indicate that Leydig cell differentiation precedes the onset of spermatogenesis.
The onset of testicular differentiation in the rat: An ultrastructural study
Authors: Merchant‐Larios Horacio
Published: February 2005

The structure of developing rat testes was studied by light and electron microscopy. Ultrastructural differentiation of Sertoli and Leydig cells was followed from 14 days of gestation through birth. Specialized morphology in Sertoli cells was first seen at 16 days of gestation. In these cells the rough endoplasmic reticulum increased and became organized as numerous short cisternae loaded with a homogenous material. Typical Leydig cells were found among the stromal cells, around day 17 of gestation.

There is good correlation between the time of appearance of ultrastructural specialization and published data on secretory capacity of the fetal testes, in respect to the inhibition and differentiation of the Müllerian and Wolffian ducts.
The effect of frozen ovarian autografts on compensatory ovulation and steroid production in unilaterally ovariectomized rats
Authors: Chihal H. J. Weems , Stone S. C. , Peppler R. D.
Published: February 2005

In the present study rats were unilaterally ovariectomized (ULO) and the surgically removed ovary was frozen for 13 days. After allowing the remaining ovary to compensate with respect to number of ova shed, the frozen graft was thawed and transplanted subcutaneously to determine the effect on ovulation number, cycle length, uterine weight, ovarian weight and plasma levels of estradiol‐17 β (E2) and progesterone.

Rats ULO at 45 days of age, which received an autograft 13 days later, had a decrease in the number of eggs shed as compared to control ULO rats (6.4 ± 0.8 vs. 11.1 ± 0.9 eggs, respectively) and a decrease in plasma E2 (14.5 ± 1.7 vs. 21.0 ± 1.5 pg/ml, respectively). No differences were observed in progesterone concentration, uterine weight, ovarian weight or cycle length. In contrast, rats ULO at 31 days of age, which received an autograft 13 days later, showed no differences in comparison to control ULO rats. Castrates which received ovarian autografts developed cycling vaginal smears and had increased E2 (31.9 ± 4.3 pg/ml) and decreased progesterone (18.3 ± 1.9 ng/ml) levels.

Since ULO animals with autografts shed fewer ova, the present study demonstrates that the amount of ovarian tissue influences ovulation number either by utilization of gonadotropins or by an, as yet, undefined mechanism.
A comparative morphometric analysis of the effects of thyroxine and acth on the zona fasciculata of rat adrenal cortex
Authors: Moore N. A. , Boler R. Keith
Published: February 2005

The effects of thyroxine and ACTH on the ultrastructure of cells of the adrenal zona fasciculata were studied by morphometric analysis and compared by two‐way analysis of variance. The results indicate that the effects of thyroxine and ACTH are different and independent. The statistically significant differences in effect of thyroxine and ACTH are: thyroxine causes an increase in the volume fraction of mitochondria and a decrease in the volume fraction of endoplasmic reticulum independent of ACTH; thyroxine causes a decrease in surface density of mitochondria and endoplasmic reticulum in the absence of ACTH, but in the presence of ACTH this effect is moderated by an interaction of thyroxine and ACTH. There were no statistically significant effects of either thyroxine or ACTH on volume fraction or surface density of liposomes.
Prenatal development of the eye in the golden hamster
Authors: Jackson Caroline Goode
Published: February 2005

Prenatal development of the eye in golden hamsters is described at the light microscopic level as twelve periods based on salient morphological features. Period one includes shallow and deepened optic sulci in the cephalic neural plate and closing prosencephalon. Period two shows V‐shaped prosencephalic evaginations, and Period three, bulbous vesicles. Contact of the retinal disc and lens placode at Period four precedes presumptive retinal invagination and lens pit formation during Period five. During Period six an open lens vesicle, precociously expanded dorsal and lateral optic cup regions and widespread optic fissure margins are evident. A spherical lens lumen, deepened optic cup and narrow optic fissure characterize Period seven. At Period eight posterior lens fibers are elongated, the optic cup is expanded ventrally, and optic fissure margins are juxtaposed or fusing. By Period nine the lens lumen is nearly or completely occluded, the optic fissure is essentially fused and axonal fibers are exiting from the globe. During Period ten corneal components are associated, axonal processes extend to the diencephalon, and lid folds cover more than half of the cornea. By Period eleven eyelids are fused. Anteriorly the pigmented epithelium is thickened and densely pigmented; outer and inner neuroblastic retinal layers are clearly distinguishable. Period twelve is marked by conspicuous anterior folds of pigmented epithelium; a relatively anuclear zone virtually separates outer and inner neuroblastic layers of the retina.
Proximal tubule tendrils: Fact or artefact
Authors: Bulger Ruth Ellen , Siegel Frances Lea , Pendergrass Robert
Published: February 2005

Tendrils have been reported to radiate from luminal surfaces of proximal tubules in rat kidneys by Andrews and Porter ('74) using scanning microscopy, but they were not seen by Bulger et al. ('74). In this study, the perfusion procedure of Andrews and Porter was re‐investigated. Tendrils were found only in regions which had characteristics of poor fixation. They were especially prominent if the perfusion pressure was purposely allowed to fall and subsequently increased to re‐expand the tubules. The tendrils could then be seen in all portions of the proximal convoluted tubule and not exclusively in the initial portion as previously reported.
Hydronephrosis in the mouse: The effects of the short‐ear gene, sex and ureteral vascular system
Authors: Wallace Margaret E.
Published: February 2005

The short‐ear gene in the mouse, se, affects a number of soft tissues; skeletal effects result in reduced body cavities. A high incidence of hydronephrosis in short‐ear genotypes has been ascribed to pressure on the lower ureter resulting from crowding of organs in the body cavity. This study concerns the ureteral vascular system as observed in 861 autopsies of mice of varying age, of the three short‐ear genotypes, drawn from ten stocks. Incidence and expression of hydronephrosis is greater in short‐ear males than in females, and the ratio between the two varies from one stock to another. This study seeks an explanation. Short‐ear genotypes have an abnormally high incidence of unusual ureteral veins, hydronephrosis being strongly associated with the more posterior ones. Ureteral veins most closely associated with hydronephrosis involve the renal, gonadal and iliac veins. The spermatic vein's more posterior position, compared with the ovarian, is strongly correlated with the sex difference in posterior ureteral venation and thus with the sex difference in incidence of hydronephrosis. Stocks are compared according to the amount of selection for fitness of shortear genotypes; there is a reduced incidence of hydronephrosis with selection, accompanied by fewer posterior ureteral veins. Age also affects hydronephrosis; its expression increases slightly with age, and the male sese progeny of young mothers appear to be particularly prone to hydronephrosis. Three skeletal mutants segregate; of these fidget, fi, causes a type of hydronephrosis differing some what from that caused by se..
Surface view of an injected human lung shortly before the fetus becomes viable
Authors: Boyden Edward A.
Published: February 2005

These figures of a silicon‐rubber‐injected fetal human lung illustrate the precocious development of filaments (future alveolar ducts) of the pulmonary acini. In contrast, there is a long delay in the differentiation of respiratory bronchioles. The former are the first to sustain respiration.
Anastomosing tubular arrangement of the exocrine pancreas
Authors: Bockman Dale E.
Published: February 2005

Wax reconstructions of zymogen‐containing cells in rat show the arrangement of the exocrine pancreas to be a branching, anastomosing system of tubules which vary in diameter and end blindly. This arrangement is not that of a true acinar gland.
Specific response of ovarian and uterine veins of mice to sex hormones
Authors: Forbes Thomas R. , Kapadia Shanta E.
Published: February 2005

Pellets of glass (control), progesterone (P), testosterone (T), and estradiol‐17β (E) were placed on the mesentery or subcutaneously in the flank in ovariectomized (O) and ovariectomized‐hysterectomized (OH) mice, insuring that all or most of the hormone would pass through the superior mesenteric or circumflex iliac veins. After 21 days the diameters of these and of the ovarian, uterine, and femoral veins and inferior vena cava were measured at autopsy. T and E caused significant enlargement of the uteri; E was also responsible for bladder distention. The ovarian and uterine veins enlarged significantly in mice treated with T and E as compared to the controls. All other veins failed to respond to P, T, and E. The evidence demonstrates a specific response of ovarian and uterine veins in O and OH mice to T and E.
Sertoli‐Sertoli junctions and Sertoli‐spermatid junctions after efferent ductule ligation and lanthanum treatment
Authors: Ross Michael H.
Published: February 2005

Seminiferous tubules, partially dilated by ligation of the efferent ductules, were examined after treatment with lanthanum. Lanthanum penetrated the intercellular spaces of the seminiferous epithelium, but only to the level of the Sertoli‐Sertoli junctions. Further penetration from the interstitial surface of the tubule was restricted by membrane fusions (tight junctions) at the junctional complex. Lanthanum also penetrated the epithelium from the luminal surface permeating the adluminal intercellular spaces, including the site of the Sertoli‐spermatid junction. The lanthanum occupying the Sertoli‐spermatid junctional site appeared as a slightly narrower electron‐opaque zone than that found in the non‐specialized intercellular areas. The findings clearly reveal that only the Sertoli‐Sertoli junctional site forms a restrictive barrier. In contrast to the specializations of plasma membrane which form the tight junction, the associated filaments and cisterna of endoplasmic reticulum may be components more directly related to maintaining and regulating cell adhesion.
Nigro‐amygdaloid fiber connections in the cat
Authors: Kaelber William W. , Afifi Adel K.
Published: February 2005

Relatively discrete unilateral lesions were made in the lateral portion of the substantia nigra of eight cats and in the medial substantia nigra of two. After a 10‐day survival period the animals were killed, brains were stored in buffered 10% formalin, and frozen sections were stained for degenerating axons and terminals, or by Weil and cresyl violet methods. Electrodes passed through the medial suprasylvian gyrus, pulvinar and/or posterolateral thalamic nucleus and the medial geniculate body. The stria terminalis and hippocampus were undamaged. Degeneration from the lesion followed two paths. One projected through the reticular nucleus into the internal capsule and then ventrolaterally below the putamen to enter the lateral and central amygdaloid nuclei, with degenerated terminals. The second path ran dorsolaterally in the internal capsule to enter the external capsule where some of the fibers spread into the lateral amygdaloid nucleus. It appears that some of the terminals in the lateral amygdaloid nucleus are from the external capsule. Perhaps these connections link the extrapyramidal system to the amygdaloid body.
The neurohypophyseal capillary bed. I. Anatomy and arterial supply
Authors: Page Robert B. , Bergland Richard M.
Published: February 2005

Vascular casts of the pituitary‐median eminence complex of mice, rats, dogs, sheep and monkeys were examined with the scanning electron microscope. Microfil‐injected specimens of the rabbit and monkey pituitary‐median eminence complex were examined by light microscopy after intracranial internal carotid artery occlusion. In each species a common neuropophyseal capillary network was found uniting infundibulum (median eminence), infundibular stem and infundibular process. This capillary bed is supplied from above by superior hypophyseal arteries and from below by inferior hypophyseal arteries. An artery to the infundibular stem was found in some species.

With occlusion of the intracranial internal carotid arteries, flow through superior hypophyseal arteries did not occur. Yet the entire neurohypophyseal capillary bed filled upon injection with Microfil.

These observations suggest the concept of a restricted arterial supply to the median eminence with drainage to the underlying adenohypophysis on one hand and to the infundibular process with drainage to the systemic circulation on the other must be modified and that blood flow within the neurohypophyseal capillary bed (between infundibular process and median eminence) occurs.
Ultrastructure of traumatic cataractogenesis in the frog: A comparison with mouse and human lens
Authors: Rafferty Nancy S. , Goossens William
Published: February 2005

Normal and needle‐punctured lenses of Rana pipiens were examined with the electron microscope in order to characterize the sequence of ultrastructural changes that follow the injury over a 5‐month period. Results were compared with those obtained previously in experimentally injured mouse and accidentally injured human lenses. The normal adult frog lens was found to have a morphology similar to that of mammalian lenses. As in the human, frog lens epithelial cells contained scattered microfilaments and were connected by desmosomes and gap junctions. They differed from mouse cells, which had been shown to lack desmosomes and to have microfilaments organized into dense bundles. These differences are postulated to be related to the degree of accommodative deformation of the lens displayed by these species.

After injury, cellular debris and fibrin, accumulated in the wound, were phagocytized by extrinsic cells derived from the blood and ocular tissues. Leucocytes, pigmented cells and fibroblasts remained in the wound for eight weeks, along with epithelial cells which proliferated and migrated from the wound margins. Epithelial cells showed an increase in those organelles associated with protein synthesis and transport, and in microfilaments. In cataractous lenses, epithelial cells showed changes in matrix, and lens fibers became organized into smaller, denser compressed units. At five months, considerable healing had taken place, but localized opacities persisted in many frog lenses.
The effect of heterologous antisera on embryonic development. XIII. Lack of effect of antisera to alpha fetoprotein
Authors: Leung Christopher C. K. , Watabe Hiroyuki , Brent Robert L.
Published: February 2005

This investigation was carried out to determine whether heterologous antisera to alpha fetoprotein (AFP) are embryotoxic to developing rat embryos. Homogeneous rat AFP was isolated and antisera directed against this glycoprotein were produced in rabbits, horse and goat. The effect of the antisera on embryonic development was examined by injecting the antisera intraperitoneally into pregnant rats on the ninth, eleventh and thirteenth days of gestation. The results demonstrated that there was no evidence of increased incidence of fetal abnormalities in 472 surviving fetuses of 42 injected rats. There was no evidence of increase embryonic death or retardation of intrauterine growth following administration of the antisera on the ninth, eleventh and thirteenth days of gestation. The localization of the injected antisera was examined by the indirect immunofluorescent method. The results showed that the heterologous AFP antibodies localized specifically in the visceral yolk sac placenta. No antibody localization was observed in the embryo proper or the chorioallantoic placenta. It is speculated that the localization of AFP antibodies in the visceral yolk sac does not interfere with the embryotrophic function of the visceral yolk sac placenta.
Fine structural features of adrenergic nerve fibers and endings in the pineal gland of the rat, ground squirrel and chinchilla
Authors: Matsushima Shoji , Reiter Russel J.
Published: February 2005

The ultrastructural features of the adrenergic nerve fibers in the pineal glands of the rat, ground squirrel and chinchilla are described. Frequencydistribution histograms of diameters of granulated and non‐granulated vesicles in the adrenergic nerve endings demonstrate that the pineal nerve endings in the chinchilla contain a considerable number of large granulated and non‐granulated vesicles, in contrast to those in the rat and ground squirrel. Synaptic ribbons seen in the pinealocytes of the ground squirrel were often localized near that plasma membrane which lay in close proximity to the axolemma of adrenergic nerve fibers. This observation may indicate that the synaptic ribbons are involved in the functional interconnection between pinealocytes and adrenergic nerve fibers. Localized dilations of the adrenergic nerve fibers were commonly observed in the pineal glands of all species examined. In addition to a variety of axonal constituents, various forms of inclusion bodies were tightly packed within these axonal dilations. The accumulation of the inclusion bodies may represent degenerative changes which occur in the pineal adrenergic nerve fibers in relation to the functional activity of the pineal gland.
The thyroid in the spontaneously hypertensive rat: A light and electron microscopic study
Authors: Krupp P. P. , Thomas L. L. , Alpert N. R. , Frink R.
Published: February 2005

The present study was undertaken to seek ultrastructural changes in the thyroid gland of the spontaneously hypertensive rat which would contribute to the understanding of previously reported abnormalities in thyroid function. Light and electron microscopic observations and measurements of plasma T3 and systolic blood pressure were recorded from a colony of Wistar‐Kyoto rats (WKY) and of spontaneously hypertensive rats (SHR). The systolic blood pressure of SHR was significantly higher than that of WKY but the plasma T3 levels of the two groups did not differ significantly. After administration of propylthiouracil (PTU), serum T3 levels and systolic pressure of both groups decreased. The size of the thyroid follicles in SHR was highly variable throughout the gland, and the colloid contained unevenly dense areas and cell debris. The follicular cells contained slightly dilated rough surfaced endoplasmic reticulum (ER) and numerous pleomorphic bodies of uneven density. After treatment with PTU, the vessels between the follicles of SHR did not become as dilated as those in WKY but the fine structure of follicular cells in SHR was similar to that of WKY and was characteristic of the typical thyroid response to PTU administration. We suggest that the thyroid in SHR does not respond adequately to the elevated TSH levels reported to be present in these animals, although it can respond to the highly elevated TSH levels which occur with PTU administration. This impairment most probably involves defects in synthesis and/or secretion of thyroid hormones in response to TSH stimulation.
Precocious induction of secretory granules by hormones in convoluted tubules of mouse submandibular glands
Authors: Kumegawa Masayoshi , Takuma Taishin , Takagi Yoshihiko
Published: February 2005

Precocious differentiation of convoluted tubules of the submandibular glands of mice was induced by daily injection of thyroxine, insulin, hydrocortisone and 5α‐dihydrotestosterone from day 4 after birth. This treatment induced enlargement of the tubules and synthesis of secretory granules in the tubules. Treatment with 5α‐dihydrotestosterone alone had no effect on enlargement of the tubules or synthesis of the granules. These findings suggest that, besides androgenic hormones, these three hormones are also involved in synthesis of granules in developing mice.
The interaction of clomiphene, estradiol, and progesterone in the control of rat uterine glycogen metabolism
Authors: Poteat William L. , Bo Walter J.
Published: February 2005

Uterine glycogen accumulation was studied in ovariectomized rats treated with all combinations of clomiphene citrate (0.25 mg/kg) estradiol (1.0 μg) and progesterone (5.0 mg). The rats were given three consecutive daily dosages and killed 24 hours after the final dosage. Based on biochemical data, either estradiol or clomiphene increased uterine glycogen concentration and total glycogen, but progesterone did not. Progesterone significantly suppressed both the estradiol and clomiphene‐induced glycogen increases. Based on the histochemical results, progesterone also suppressed the estradiol and clomiphene‐induced glycogen responses, but the tissue affected differed. Clomiphene markedly increased luminal epithelial glycogen whereas estradiol induced primarily myometrial glycogenesis. Progesterone completely suppressed the clomiphene‐induced epithelial effect and partially suppressed the estradiol‐induced myometrial effect. Clomiphene also suppressed the estradiol induced myometrial response. The results indicate that progesterone does have a significant interaction with clomiphene in the control of uterine morphology and biochemistry. The results also stress the importance of correlated histochemical and biochemical studies in the study of clomiphene‐induced uterine glycogenesis.
Osteopetrosis in the toothless (tl) rat: Presence of osteoclasts but failure to respond to parathyroid extract or to be cured by infusion of spleen or bone marrow cells from normal littermates
Authors: Marks Sandy C.
Published: February 2005

Osteoclasts have been observed for the first time in toothless (tl) rats, a mutation which inherits osteopetrosis as an autosomal recessive. The ability of tl rats to raise the serum calcium concentration after injection of parathyroid extract was severely limited when compared with normal littermates. In addition, osteopetrosis in tl rats is not cured by radiation and infusion of normal spleen or bone marrow cells from normal littermates, a method known to cure osteopetrosis in mutants of this and other species. This indirect evidence for a reduction in bone resorption as a cause of osteopetrosis in this mutation and the failure of transplanted cells to cure the disease are discussed in relation to the development and function of osteoclasts.
Initial intramembraneous osteogenesis in vitro
Authors: Marvaso Vicki , Bernard George W.
Published: February 2005

Calvariae of fetal mice 12 to 13 days in utero were placed in Rose chambers and cultured in BGJb medium supplemented with 20% fetal calf serum and antibiotics. After periods of 7 and 12 days, the explants were harvested and processed for light and electron microscopy. The mesenchymal cells, after a brief lag time, differentiated into osteoblasts which produced woven bone. Light and electron microscopic observations showed that in vitro, as well as in vivo, growth and development share all of the same characteristics of initial intramembraneous osteogenesis: (1) migration and differentiation of mesenchymal cells into osteoblasts, (2) the subsequent appearance of matrix vesicles in the extra‐cellular space, (3) crystallization of hydroxyapatite within and about these vesicles, (4) growth of hydroxyapatite crystals into spheroidal nodules of bone, and (5) the subsequent fusion of these nodules into seams of woven bone. Thus cellular involvement in initial osteogenesis has been observed in a system where differentiation into osteoblasts and initial calcification takes place in vitro, suggesting that the events responsible for these phenomena have occurred within the cells prior to their morphological differentiation.
The effects of continuous illumination (LL) and continuous darkness (DD) on the daily rhythms of membrane‐bound and microsomal enzymes in the adrenal gland and kidney of the rat
Authors: Margolis Ronald
Published: February 2005

A daily rhythm was demonstrated in levels of specific activity for the Na, K‐ATPase and glucose‐6‐phosphatase enzymes in adrenal and renal subcellular fractions in the rat. A bimodal daily rhythm was observed for 5′‐nucleotidase in a renal subcellular fraction. The rats were maintained on a 12:12 light‐dark (LD) regimen. Animals were killed at approximately 4‐hour intervals.

The daily rhythm in Na, K‐ATPase and glucose‐6‐phosphatase activities persisted in animals maintained under continuous illumination (LL) and continuous darkness (DD). The 5′nucleotidase activity persisted under LL, and under DD.

The data from the enzyme assays were analyzed by fitting to a cosinor regression model designed to assess the rhythmic nature of the findings. A linear transformation method was applied to assess the closeness of fit to the cosinor regression model.

The Na, K‐ATPase and glucose‐6‐phosphatase activities appeared to be endogenous circadian rhythms. Glucose‐6‐phosphatase activity in renal fractions appeared to be influenced by the feeding cycle. The 5′‐nucleotidase enzyme appeared to have an ultradian rhythm. The ultimate derivation and significance of these observed rhythms remains to be determined; however, they appear to be independent of the light‐dark cycle.
Electron microscopy of degenerating axons and terminals in spinal trigeminal nucleus after tooth pulp extirpations
Authors: Westrum Lesnick E. , Canfield Robert C.
Published: February 2005

Following multiple tooth pulp extirpations, electron microscopic preparations show degenerating axons and synaptic terminals in the same region of the brain stem trigeminal nucleus previously demonstrating degeneration by light‐optical methods. The observations confirm the phenomenon of transganglionic degeneration in this system and identify the class of central nervous system axons and synapses specifically related to innervation of the teeth.
Sarcotubules and subsarcolemmal caveolae and their continuity with the sarcolemma in frog striated muscle
Authors: Leeson Thomas S.
Published: February 2005

After using tannic acid mordanting, T‐tubules and subsarcolemmal caveolae show a dense staining with lead citrate, with some increase in contrast also of the sarcolemma, in frog muscle. While a few T‐tubules show direct continuity with the extracellular space, the majority open indirectly via caveolae. Caveolae lie immediately beneath the sarcolemma, mainly in a single row, and are more numerous in relation to I‐bands.
Fenestrations in regenerating skeletal muscle capillaries
Authors: McKinney Ralph V. , Singh Baldev B. , Brewer Phyllis D.
Published: February 2005

A new observation of fenestrae with diaphragms in the endothelial wall of regenerating skeletal muscle capillaries is described in seven‐day‐old wounds of the cremaster muscle of adult male guinea pigs. The fenestrations were 44 nm in diameter and contained diaphragms with a central dense structure. These findings suggest an additional route for physiological exchange mechanisms in wound capillaries.
Elastic tissue in the limiting membrane of the human seminiferous tubule
Authors: De Menezes Amadeu Peixoto
Published: February 2005

The structure and distribution of elastic tissue were studied in the limiting membrane of the seminiferous tubule from normal human testis. The elastic and elastic‐related fibers (oxytalan and elaunin) were recognized by their tinctorial and ultrastructural characteristics. The connective structures of the limiting membrane, including the fibrotubules and the amorphous material of the elastic system, were studied after tannic acid‐glutaraldehyde fixation. Fibrotubules (oxytalan fibers) were observed in almost all intercellular spaces of the limiting membrane, closely related to the contractile cells; the elaunin fibers (patches of amorphous material surrounded by bundles of fibrotubules) were evident in the outermost layers. The function of this system of elastic tissue and myoid cells is discussed, considering the permeability of the limiting membrane and the role of the myoid cells in the elastogenesis and contractility of the seminiferous tubule.
Studies of the mechanism of spleen cell cure for osteopetrosis in ia rats: Appearance of osteoclasts with ruffled borders
Authors: Marks Sandy C.
Published: February 2005

After ia (osteopetrotic) rats receive whole body radiation and an injection of spleen cells from a normal littermate, the dense, sclerotic skeleton characteristic of osteopetrosis is rapidly remodeled and becomes normal in appearance radiographically and histologically within three weeks. The mechanism of this skeletal transformation has been explored in cured ia rats by light and electron microscopic examination of osteoclasts.

In ia rats less than 25 days of age, osteoclasts viewed by electron microscopy lack a ruffled border‐the extensive elaboration of plasma membrane next to the bone surface. Cured ia rats have osteoclasts with ruffled borders indistinguishable from those of normal littermates. In ia rats that receive only 600 rads whole body radiation, osteoclasts are still present three weeks later, but appear abnormal by light microscopy, with dense nuclei and lacking cytoplasmic vacuoles next to the bone surface. Cured ia rats have two types of osteoclasts, one type indistinguishable from osteoclasts of normal littermates by light microscopy, the other resembling osteoclasts of ia rats that received radiation only.

These data indicate that the mechanism of the spleen cell cure for osteopetrosis in ia rats is rapid remodeling of the skeleton produced by osteoclasts with ruffled borders. Whether normal spleen cells produce these osteoclasts directly by cell division or indirectly by elaboration of some unknown local factor required for formations of ruffled borders by ia osteoclasts is not known.
A freeze‐fracture study of exocytosis and reflexive gap junctions in human ovarian decidual cells
Authors: Herr John C. , Heidger Paul M.
Published: February 2005

Fine‐structural features of ovarian decidual cells and their mode of secretion were examined by means of freeze‐fracture microscopy. Unique cortical peduncular processes contained secretory vesicles within the expanded peduncle tip, the membrane‐leaflets of which exhibited a particle‐poor E face adjacent to the vesicle lumen and a P face containing a greater particle number. Exocytosis from attached peduncles involved release of vesicular profiles 40–55 nm in diameter; small particles 8.5–11.5 nm in diameter were also observed at degranulation sites. In fractures revealing the E face of the plasmalemma, cytoplasmic portals at the bases of peduncular stalks were distinguishable from endocytic vesicles.

The frequent occurrence of reflexive gap junctions associated with peduncles was shown by freeze‐fracture. However, there appeared to be no consistent spatial relationship between gap junctions, secretory peduncles, or sites of exocytosis. Freeze‐fracture analysis of the topography of reflexive gap junctional profiles revealed that such gap junctions share basic similarities with intercellular gap junctions. These similarities include particle size (8–10 nm); number of particles within clusters (20–40); and the presence of 5–15 nm particle‐free aisles. The finding in the present study of reflexive gap junctions occurring between peduncles and the cell soma, as well as between peduncles, suggests that the original definition of reflexive gap junctions as those existing between processes of the same cell should be broadened to include any gap junctional specialization formed between portions of the plasma membrane of one cell.