bluuebunny/crossref_metadata_2025_split huggingface dataset:
The fine structure of the trophospongial layer of the kangaroo rat placenta
Authors: Tibbitts F. Donald , King Barry F. 
Published: February 2005

AbstractThe trophospongial layer of the near‐term kangaroo rat placenta was examined in the electron microscope. Two ultrastructurally different cellular zones were distinguishable – an inner zone adjacent to the labyrinth and a basal zone located mesometrial to the inner zone. Inner zone cells contained a well developed granular ER and Golgi apparatus as well as polymorphous membrane‐limited granules. The cells also contained modest amounts of glycogen and lipid droplets. Basal zone cells were also rich in ER; some cells had dilated ER cisternae containing a highly structured material which appears as a sheet of hexagons when viewed en face. Basal zone cells may, among other things, function as glycogen storage cells, since they had large cytoplasmic accumulations of glycogen. Unlike the situation in some other rodents, maternal blood draining from the trophospongial layer was always contained in channels lined by a layer of squamous cells which, in turn, was separated from the trophospongial cells by a basal lamina. The trophospongial zones are compared with the trophosngial regions of other rodent placentas and possible functions are considered.
Comparative ultrastructural analysis of two tortoise bladders, Testudo graeca and Geochelone carbonaria
Authors: Strum Judy M. , Danon David 
Published: February 2005

AbstractUrinary bladders from the desert tortoises, Testudo graeca and Geochelone carbonaria were removed at specific times during the year and studied by electron microscopy. Three epithelial cell types were found in both species in all bladders examined: (1) granular cells, (2) mitochondria‐rich cells, and (3) basal cells. Cells analogous to these three types have also been observed in amphibian bladders (from to ad Bufo marinus and bullfrog, Rana catesbiana) and reptilian bladders (from Pseudemys scripta and Clemmys caspica). Both tortoises have an incomplete layer of basal cells so that the granular and mitochondria‐rich cells extend from the lumen to the basement membrane: some thing not observed in bladders from bullfrog or turtles. A flask‐shaped light cell was observed in the Geochelone carbonaria bladder obtained in April. No counterpart of this cell was seen in the same species sacrificed in January, or in any of the Testudo graeca bladders, although a similar cell has been described in the turtle, Pseudemys scripta (Rosen, Expt. Molec. Path., 12: 286–296, 1970). This study was undertaken to characterize the cell types present in tortoise bladder and to compare them with cell types in the bladder of the turtle, bullfrog and toad.
Effect of uterine artery ligation on ovulation in the rat
Authors: Peppler Richard D. 
Published: February 2005

AbstractFemale rats were divided into six groups: (1) control, (2) one uterine artery (a.) ligated near the utero‐tubal (U‐T) junction, (3) one uterine a. ligated at the level of the cervix, (4) both uterine aa. ligated separately at the U‐T junction, (5) both uterine aa. ligated separately at the cervix and (6) both uterine aa. tied with one ligature at the cervix. Segmental aa. were disrupted in all experimental groups except group 6. Animals were allowed to recover for ten days and killed the first metestrus thereafter. Number of eggs ovulated was determined by flushing the oviduct with saline solution and counting the ova.Control rats ovulated 5.0 ± 0.4 eggs per ovary. Groups 2 and 3 had an increase in the number of eggs shed from the ovary on the non‐ligated side. In contrast, a decrease in the number of ova shed occurred on the ligated side. When both aa. were ligated separately (groups 4 and 5), irrespective of location, a decrease in the number of eggs shed by both ovaries was evident. No effect was found when only one ligature was placed near the cervix (group 6).The data demonstrate that blood supply to the ovary via the uterine artery is essential for the full complement of eggs to be shed.
Response of tanycytes of rat median eminence to intraventricular administration of colchicine and vinblastine
Authors: Schechter Joel , Yancey Barbara , Weiner Richard 
Published: February 2005

AbstractThe effects of colchicine and vinblastine on tanycytes of the rat median eminence have been studied using the electron microscope. Colchicine and vinblastine were administered by intraventricular cannulation into the third ventricle and demonstrated distinct morphological effects on tanycyte microtubules. Highest drug doses administered were 50.0 μg in 5.0 μl of saline initially, followed by an additional 50.0 μg of these agents infused in a volume of 13.0 μl saline over an hour. Colchicine treatment resulted in the formation of large crystalloids within tanycytes, coincident with the disappearance of microtubules, all along the ventricular surface. Nonetheless the tanycytes appeared able to maintain a continuous tight lining, as in controls, although some crystalloids were observed beneath the ventricular surface, either within tanycyte processes or within neuronal processes. Vinblastine treatment also resulted in the formation of identical crystalloids but at highest doses thoroughly destroyed the tanycyte lining of the median eminence and exposed cellular elements below the surface to the drug. Portal capillaries approaching the ventricular surface were generally free of any signs of drug response to either colchicine or vinblastine.
Circadian influence on the frequency of labeled mitoses method in the stratified squamous epithelium of the mouse esophagus and tongue
Authors: Burns E. Robert , Scheving Lawrence E. , Fawcett Deborah F. , Gibbs William M. , Galatzan Russell E. 
Published: February 2005

AbstractThe frequency of labeled mitoses method (FLM) was used to study the cell kinetics in the stratified squamous epithelium of the mouse esophagus and tongue. FLMs were generated by injecting tritiated thymidine (TdR) at two different phases of the mouse circadian system: TdR was injected into one group of mice at 0900 and into a different, second group of mice at 2100. Three variables were monitored for each group; (1) the FLM, (2) the mitotic index and (3) the grain count over the labeled mitotic figures. In both the esophagus and the tongue there was a circadian rhythm in the mitotic index with the peak occurring during the first half of the diurnal phase and the trough occurring during the first half of the nocturnal phase. The FLM curves from each group revealed the following data:

Transit time in G2+1/2M (TG2+1/2M)
Transit time in S phase (TS)

hours
hours

Esophagus — TdR at 0900
2.5
5.3

Esophagus — TdR at 2100
4.5
3.5

Tongue — TdR at 0900
4.2
5.1

Tongue — TdR at 2100
4.2
5.5

Second waves of labeled mitoses were seen in the esophagus and tongue when TdR was injected at 0900. No second wave of labeled mitoses occurred in either the esophagus or the tongue when TdR was injected at 2100. For the esophagus the grain counts of the labeled mitotic figures in each group indicated that the rate of DNA synthesis was greater during late S phase, whether the TdR was injected at 0900 or 2100. During most of the S phase the rate of DNA synthesis was significantly greater in the TdR at 2100 group, which is the time of the circadian system when the esophagus demonstrated a relatively short Ts. In the epithelium of the tongue there were a few statistical differences in the rate of DNA synthesis between the groups and during the duration of the S phase within either group, but these data were difficult to interpret.The data demonstrate the influence of the circadian system in cell kinetic work and in the interpretation of data obtained with the FLM in renewing populations of cells which are not totally asynchronous.
Localization of rabbit gamma globulins in the mouse visceral yolk sac placenta
Authors: Gardner Martha M. 
Published: February 2005

AbstractThe yolk sac placenta has been implicated previously in transmission of passive immunity to the fetus. This work uses an immunohistochemical technique devised by Sternberger et al. (1969) to study this problem. Rabbit serum containing gamma globulins was injected into the uterine lumen of the White Swiss mouse during the last third of pregnancy. Two or four hours later yolk sacs were removed and fixed in 2% paraformaldehyde or freeze‐dried and fixed with paraformaldehyde vapors. Finely chopped tissue was treated with (1) sheep antiserum to rabbit gamma globulin, (2) an antigen‐antibody complex consisting of horseradish peroxidase and rabbit anti‐horseradish peroxidase and (3) hydrogen peroxide and 3,3′‐diaminobenzidine. Reaction product was heavily concentrated in visceral yolk sac endodermal cells, frequently deposited in endothelial cells of vitelline vessels, and rarely in the serosal basement membrane and mesothelial cells which border the exocoelomic cavity. This supports evidence of other workers that the yolk sac membrane rapidly absorbs substances with which it comes in contact, transport into vitelline vasculature is a route of transfer from mother to fetus, and possible transfer into the exocoelomic cavity and thence to the amniotic cavity may occur in mice.
DNA synthesis and cell proliferation in the simple liver acinus of 10 to 20‐day‐old rats: Evidence for cell fusion
Authors: LeBouton A. V. 
Published: February 2005

AbstractRadioautography after 3H‐thymidine injection, mitotic arrest by colchicine and camera lucida drawings were used to study DNA synthesis, mitosis, formation of binucleated cells and morphogenesis in the simple liver acinus of Rappaport in 10–20‐day old rats. By ten days the arrangement of hepatic cell plates had already attained the adult configuration — irregular and thick in acinar zone 1 (periportal), straight and thin in acinar zone 3 (pericentral). The DNA synthetic index of parenchymal and bile duct cells slowly decreased during the observation period. Zonal labeling remained steady in the relationship: zone 1 > zone 2 > zone 3. Mitosis of parenchymal and bile duct cells reached a peak at 12 days, decreasing slowly thereafter. Mitosis also exhibited the relationship zone 1 > zone 2 > zone 3. The number of binucleated cells remained constant until after day 14 when it increased rapidly. Zonal distribution of binucleated cells was just the reverse of that for DNA synthesis and mitosis, that is zone 3 > zone 2 > zone 1. Radioautographic studies of binucleated cells labeled with 3H‐thymidine indicated that a small percentage of them were formed by fusion of mononucleated cells.Conclusions are: (1) the 10–20‐day old rat liver is expanding its cell population primarily in acinar zones 1 and 2 while overt differentiation is occurring in acinar zone 3, (2) ingestion of solid food around day 16 may be related to binucleated cell production due in part to altered portal venous blood changing the cellular microenvironments, (3) binucleated cells arise by suppression of cytokinesis, cell fusion and/or other non‐mitotic routes.
Specialized junction in the distal convoluted tubule of rat kidney
Authors: Giacomelli Filiberto , Wiener Joseph 
Published: February 2005

AbstractThe ultrastructure and permeability of the apical junctions between epithelial cells of the distal nephron have been studied in rat kidney using a colloidal lanthanum tracer and uranyl acetate staining en bloc. The apical intercellular junctions of the macula densa and juxtaglomerular segment of the early distal convoluted tubule measure up to 0.5 μ in length and about 50 Å in width. Lanthanum permeates the occluding portion of these junctions in a discontinuous manner, defining a series of closely spaced and parallel lines of fusion that run in a direction perpendicular to the apical‐basal axis of the tubular cells. The apical junctions of the remainder of the distal convoluted and cortical collecting tubules are impermeable to lanthanum. This distinctive apical tight junction can account for the greater permeability to ions of the early distal convoluted vs. late distal convoluted and cortical collecting tubules.
Cellular composition of the bone marrow in the chicken. I. identification of cells
Authors: Glick Bruce , Rosse Cornelius 
Published: February 2005

AbstractIncorporation of Fe55 in vivo was used for verifying on radioautographs the identity of chicken bone marrow cells that are in the process of heme syntheses. Under the experimental conditions all labeled cells may be considered to be linked with erythroid differentiation. They were classified into five maturational stages according to their morphology and capacity for DNA synthesis. Granulocytes were identified by the presence of specific granules. All mononuclear cells were classified as lymphocytes which had a pachychromatic nucleus, a high nucleocytoplasmic ratio, lacked the capacity for DNA synthesis, and resembled small lymphocytes of the bursa, spleen and bone marrow that bound, in vitro, anti‐chicken gamma globulins labeled with I125. Radioautography with H3TdR was used to identify proliferating and non‐proliferating members of each cell population.With the use of the morphological criteria thus established, reproducible differential counts could be performed on chicken bone marrow smears also in the absence of specific labeling. In normal, 3, 4, and 8 week old White Leghorn chicks, such counts revealed the bone marrow as a member of the lymphomyeloid complex preferentially adapted to the production and maturation of erythroid cells, while the reserve of granulocytes was found to be small compared to that of mammalian marrow. The percentage of lymphocytes appears to increase with age but, in contrast to rodent marrow, a proliferating precursor cell pool for lymphocytes could not be identified in chicken marrow up to the age of eight weeks.
The growth of the oocyte and follicle in the ovaries of monotremes and marsupials
Authors: Lintern‐Moore Sue , Moore G. P. M. , Tyndale‐Biscoe C. H. , Poole W. E. 
Published: February 2005

AbstractOocyte growth in relation to follicular growth in marsupials conforms to the uniform biphasic pattern characteristic of eutherian mammals. However, the oocyte of the marsupial is larger and completes growth in a correspondingly larger follicle. At the completion of oocyte growth the follicle, like that of eutherians, shows no appreciable accumulation of follicular fluid. The ratio of oocyte/follicular diameter in marsupials at this stage is 0.59, a value close to that of 0.55 for eutherian mammals. The oocyte nucleus of the marsupial is also significantly larger than that of the eutherian, but the oocyte nucleolus is approximately the same diameter.By contrast, the growth of the oocyte in relation to the follicle in monotremes is linear throughout the whole period of follicular growth. However, like eutherians and marsupials oocyte nuclear and oocyte nucleolar growth are arrested in the early stages of follicular growth. The diameters of the oocyte nucleus and nucleolus at the completion of growth are approximately twice those found in marsupials.It is concluded that the growth patterns of the oocyte nucleus and nucleolus are common to all mammals but that the biphasic pattern of oocyte and follicular growth which is characteristic of eutherian and marsupial ovaries is not found in the monotremes.
Crystalloid configurations in the adrenal cortex of the Siamese tree shrew (Tupaia glis)
Authors: Hostetler Jeptha R. , Cannon M. Samuel , Belt W. Duane 
Published: February 2005

AbstractCrystalloids of what appear to be smooth reticulum have been observed in the zona fasciculata and zona reticularis in both the stressed and nonstressed adrenal gland of the Siamese tree shrew (Tupaia glis). No crystalloids are observed in the zona glomerulosa. Similar crystalloids have been described in other steroid‐secreting organs, including the antebrachial organ of the lemur (Lemur catta), the parotoid gland of Bufo alvarius and in sebaceous gland cells of the Galagos and Macaques. Moreover, the crystalloids in the present investigation resemble the paracrystalline arrays of smooth reticulum present in the adrenal cortex of the fetal guinea pig. The crystalloids show much variation in degree of organization, sometimes appearing as wavy tubules parallel with one another or as fused tubules having a “donut” configuration. In addition, the crystalloids are nearly identical to configurations which have been described in mitochondrial cristae of the protozoan, Pelomyxa carolinensis.
The postnatal development of the junctional complexes of the mouse Sertoli cells as revealed by freeze‐fracture
Authors: Nagano Toshio , Suzuki Fumie 
Published: February 2005

AbstractMouse testes of newborn to adult were examined by freezefracture. Between the newborn Sertoli cells, gap junctions consisting of aggregations of the intramembranous particles (about 8 nm in diameter) are frequently found. Some of the junctions are about 1 μm in diameter and show particle‐free regions in the aggregation. Linear arrangements of a few particles, which appear to be the initial formation of the occluding junctions, are seen in the newborn Sertoli cells. The occluding junctions are arranged in a meshwork, in which the gap junctions are situated between the stages of newborn to six days of age. The particles of the occluding junctions are predominantly located on the B face in the center of the groove instead of the A face of the ridge. The occluding junctions do not appear to surround the entire circumference of the Sertoli cell of the 6‐day‐old mouse. The gap junctions decrease in size. In later stages, many parallel occluding junctions (up to forty in number) are found over one Sertoli cell surface and are distributed circumferentially around the entire cell surface, indicating establishment of the blood‐testis barrier. The occluding junctions dominate and the gap junctions diminish in number as development proceeds.
Liver hepatocyte mitotic activity after a single injection of phenobarbital in immature male rats
Authors: Argyris Thomas S. , Miller Anne 
Published: February 2005

AbstractIn contrast to multiple injections of phenobarbital, a single injection of 50 mg/kg body wt of phenobarbital into immature male rats results, after a transient increase in hepatocyte mitotic activity, in a marked decrease in hepatocyte mitotic activity to below control levels by day 3, followed by a return to control levels by day 5. This unusual pattern of hepatocyte mitotic activity can be called forth again by a second injection of 50 mg phenobarbital/kg body wt.However, a single injection of 50 mg/kg body wt of phenobarbital into immature male rats results in a pattern of change of liver wet weight, protein, and aminopyrine demethylase activity which is similar to that observed after multiple injections of phenobarbital, except that the changes are smaller in magnitude. Liver wet weight, protein, and aminopyrine demethylase activity increase and reach a peak within two days after phenobarbital injection, and then they return to control levels by five days. The same pattern of change in liver wet weight, protein, and aminopyrine demethylase activity can be elicited again by a second injection of 50 mg phenobarbital/kg body wt.
Zonulae occludentes of the rat nephron under conditions of experimental expansion of blood and/or fluid volume
Authors: Evan Andrew P. , Baker Jeffrey T. , Bengele Howard H. 
Published: February 2005

AbstractThe zonula occludens (Z.O.) has been implicated as a major pathway for passive fluid movement from lateral intercellular spaces to lumen in response to an expansion of blood or fluid volume. The present study examines the Z.O. of adult rat nephrons in control and Ringer‐Locke or whole blood infused animals to determine whether varying the conditions of passive fluid movement would influence the structure of the Z.O. Rats were infused over 20 minutes with Ringer‐Locke (7% body weight) or whole blood (2.3% body weight). In the controls, 92%–94% of all Z.O. observed in proximal tubules and 100% of Z.O. from distal tubules and collecting ducts had fused outer leaflets. The approximate linear extent of the Z.O. was 140 Å for proximal tubules, 2,500 ÅR for distal tubules and 3,000 ÅR for collecting ducts. There was no significant difference in any of these values following the infusion with either Ringer‐Locke or whole blood. We conclude that expansion of blood or fluid volume causes no detectable alteration in the fine structure of Z.O. under the conditions used in the present study.
Monosodium glutamate induced lesions of the arcuate nucleus. I. Endocrine deficiency and ultrastructure of the median eminence
Authors: Holzwarth‐Mcbride M. A. , Hurst E. M. , Knigge K. M. 
Published: February 2005

AbstractMonosodium glutamate was administered daily on days 5 through 10 postnatally at a dose of 2.5 mg/gm body weight. Counts of remaining perikarya in the arcuate nucleus of adult mice indicated approximately an 80% decrease in the number of perikarya. The arcuate lesion resulted in endocrine deficits; reproductive capacity was reduced, animals were smaller in stature and obese, and the weights of the anterior pituitary, ovaries and testes were significantly decreased while adrenals were unaffected. Light microscopic studies revealed no significant changes in thickness or general histological appearance of the median eminence. At the electron microscope level, there were no alterations in the number of nerve terminals or dense core vesicles per unit area in the contact zone. These observations suggest that afferents to the median eminence from the arcuate nucleus may form a relatively small portion of its total nerve terminal population.
Monosodium glutamate induced lesions of the arcuate nucleus. II. Fluorescence histochemistry of catecholamines
Authors: Holzwarth‐Mcbride M. A. , Sladek J. R. , Knigge K. M. 
Published: February 2005

AbstractThe effect of the monosodium glutamate (MSG) induced lesion of the arcuate nucleus on catecholamines in the arcuate nucleus and median eminence of the mouse hypothalamus was determined using the Falck‐Hillarp histofluorescence technique. The number of fluorescent perikarya in the arcuate nucleus of treated animals was decreased approximately 60%; the fluorescence intensity of surviving neurons was notably reduced. These changes were accompanied by a reduction in the intensity of fluorescence in the median eminence. Pretreatment of control and MSG‐lesioned animals with a monoamine oxidase inhibitor (pargyline) greatly increased fluorescence in the median eminence and arcuate nucleus of both groups. However, the number of fluorescing perikarya of the arcuate nucleus of the normal pargyline treated group far exceeded that of the pargyline MSG animals. It is concluded that neonatally administered MSG caused destruction of a large number of dopaminergic arcuate perikarya.