bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron microscopic observations on myoid cells of the frog's thymus
Authors: Töró I. , OláH I. , Röhlich P. , Virágh S. Z. 
Published: February 2005

AbstractMyoid cells of the thymus of hibernating frogs were examined by electron microscopy. This cell type is represented by immature, fully‐developed and degenerating cell forms. The immature forms are mainly located at the surface, whereas the developed ones are found in the inside of the thymus. A peculiar type of immature cell containing no thick filaments, but possessing a rich sarcoplasmic reticulum among the thin filaments is described. The developed myoid cells have a myofibrillar apparatus showing regular cross‐striations. The myofibrils are arranged in concentric layers around the nucleus. The proposed role and origin of myoid cells and their probable connection with myasthenia gravis are discussed.
The nature of the litter size loss in senescent hamsters
Authors: Thorneycroft Ian H. , Soderwall A. L. 
Published: February 2005

AbstractYoung and senescent female hamsters were sacrificed on days 8, 10, 12, 14 and 15 of pregnancy, and the number of viable and resorbing conceptuses was determined. The ovulation rate for each group was also recorded. At each day, there was a reduction in the litter size in senescent animals as compared to the young, but the number of ovulations in each age group was equal. The results indicated that the litter size loss, in senescent hamsters, is not due to a reduction in the ovulation rate, but to a seven fold increase in preimplantation deaths and to a two fold increase in resorption.
Responses of fatty livers of mice to carbon tetrachloride
Authors: Wilson Edward R. , Lane Williams W. 
Published: February 2005

AbstractFemale mice of the Taconic Swiss stock were fed one of the three diets described below then injected subcutaneously with 0.035 cm3CCl4/100 gm body weight in a mineral oil solution. One group was fed an adequate commercial laboratory ration, then mice were killed 12, 24 and 48 hours after CCl4; another a cholinedeficient, high‐fat, low‐protein diet for 14 days, then injected with CCl4, and killed 12, 24 and 48 hours later; and another group, a choline‐supplemented (2 gm choline chloride/100 gm diet), high‐fat, low‐protein diet for 14 days, then injected with CCl4 and killed 24 hours later.In the group fed the normal diet, the polyhalogen produced within 24 hours the expected centrolobular necrosis and glycogen depletion, involving one‐third to one‐half of the lobular areas. In fatty livers produced by feeding the choline‐deficient diet, necrosis at 24 hours post injection was limited in a majority of instances to a zone one or two cells thick immediately surrounding the central vein. Despite this decreased necrosis in fatty livers centrolobular glycogen depletion still involved one‐third to one‐half of lobules and there was an infiltration of inflammatory cells immediately adjacent to the central vein. The hepatic necrosis at 12 and 48 hours paralleled that in the normal dietary group.Feeding of the choline‐supplemented, high‐fat, low‐protein diet for two weeks produced an extremely limited parenchymal liposis. In such relatively non‐fatty livers CCl4 produced hepatic necrosis comparable to that in mice receiving normal diets. The extent of protection from the necrogenic actions of CCl4 was clearly associated with extensive intracytoplasmic liposis of hepatic parenchyma.
Temporal and cytological aspects of fertilization and early development in the guinea pig, Cavia porcellus
Authors: Hunter R. H. F. , Hunt D. M. , Chang M. C. 
Published: February 2005

AbstractA study was made of 174 eggs recovered from 58 guinea pigs killed between the first and sixth days after mating, and the cytological details from the stage of sperm penetration to the pre‐implantation blastocyst described. Eighty‐nine percent of the expected number of eggs were recovered, and 97% of these were fertilized. Embryonic development proceeded from pronuclear and 2‐cell eggs on day 1 to pre‐implantation blastocysts on day 6, the duration of each of the early cleavage stages being of approximately 24 hours. No progressive loss of embryos was found over this period, all the eggs recovered on days 4, 5 and 6 being regarded as developing normally. Passage of embryos from the Fallopian tubes to the uterus commenced on the afternoon of day 3, and the majority of embryos entered the uterus shortly after this time at the stage of 8‐ to 16‐cells. The tail of the fertilizing spermatozoon was detected in the cytoplasm of all eggs examined on day 1, in most of those examined on day 2, and frequently persisted up to the 8‐cell stage. Three dispermic eggs, each containing two distinct cytoplasmic sperm tails, were found: one of these was at the pronuclear stage, the other two being considered of 4‐ and 6‐cells respectively. Properties of adhesiveness were shown by blastocysts recovered shortly before implantation on day 6, but the characteristic “zona processes” were not seen.
Studies on hypoxia V. Effects of anoxia on developing connective tissue cells in rats
Authors: Kim Joon H. , Han Seong S. 
Published: February 2005

AbstractThe effect of anoxia on protein synthesis of developing connective tissue cells was studied by radioautography. Neonatal rats were subjected to anoxia for 20 minutes and were immediately injected with 3 μc/gm body weight of leucine‐H3intraperitoneally. They were sacrificed at different intervals after injection. Control animals were handled identically, except that atmospheric air was made available. The heads of the animals were prepared for radioautography in the standard manner. The number of grains was counted over individual fibrobalsts, osteoblasts and chondrocytes of histologically comparable regions, and the data were statistically evaluated.The number of grains per cell was significantly lower in experimental animals sacrificed at one hour after the anoxic treatment and leucine‐H3administration. At this time, the average grain number per cell in the experimental animal was less than 50% of the control. The difference was about 20% by four hours and was negligible after 24 hours. The result is interpreted to indicate that the overall protein synthesis in connective tissues is immediately but temporarily suppressed by anoxia and that such suppression might lead to a later functional disturbance among these cells.
Fate of 3H‐ribose in the rat as detected by radioautography
Authors: Gonçlalves R. P. , Bennett G. C. , Leblond C. P. 
Published: February 2005

AbstractLight and electron microscopic radioautographs of the tissues of young rats which were sacrificed at various times after a single 3H‐ribose injection revealed a wide distribution of the label.Nuclear reactions were seen over hepatocytes and other cell types. After removal of RNA by treatment with RNAse, most nuclear reactions were absent; they were, therefore, attributed to the incorporation of label into newly‐synthesized RNA. In about 2% of the nuclei, however, labeling persisted after RNAse, but was absent after DNAse treatment, indicating uptake into newly‐synthesized DNA. Hence, ribose may be taken up into nucleic acidsundergoing synthesis.In cells of liver and cartilage as well as in some muscle fibers, moderate reaction appeared over glycogen areas. Removal of the label by salivary amylase confirmed its uptake into glycogen.In mucous and other secretory cells, amylase resistant radioautographic reactions appeared over the Golgi region and later over secretion products. Presumably the label was incorporated into the glycoproteinmoieties of these secretions.Many, if not all, cells in the body appear to be able to utilize free exogenous ribose. It is presumed that ribose is first phosphorylated and then either incorporated into the RNA and DNA being synthesized in the nucleus or converted into the glucose or fructose derivatives used for glycogen and glycoprotein synthesis in the cytoplasm. That these pathways may play a significant physiological role is suggested by the recent finding of free ribose in the blood.
Fine structure of the pancreatic islet cells of normal and alloxan treated bats (Eptesicus fuscus)
Authors: Hinkley Robert E. , Burton Paul R. 
Published: February 2005

AbstractThe pancreas of the bat Eptesicus fuscus was investigated with respect to the normal ultrastructure of the islet cells, and structural alterations induced by alloxan. The ultrastructure of normal active and hibernating bat islet cells was similar. Through serial sections, B granules were shown to be disc‐shaped, and some B granules were observed to consist of up to three component plates. Vesicular configurations found in both A and B cells suggest that the Golgi complex is essential to granule formation.
Enzyme histochemistry of embryonic nasal mucosa
Authors: Shapiro Burton L. 
Published: February 2005

AbstractThe prenatal development of rodent nasal mucous membrane has been examined histochemically (lactate dehydrogenase, succinate dehydrogenase, glucose‐6‐phosphate dehydrogenase, alkaline phosphatase, PAS and PAS with diastase digestion). Localization and intensity of the enzyme systems studied were distinctly different in respiratory and olfactory areas. These differences were demonstrable by at least the second half of gestation in the animals studied. Findings in Jacobson's organs were parallel to those in olfactory areas. Each of the pathways of carbohydrate metabolism examined was present in respiratory epithelium. However, intensity was less, appeared later and was more variable in intracellular localization than that found in olfactory areas. Based on enzyme staining olfactory epithelium seemed metabolically more active than respiratory mucosa. Apical portions of olfactory epithelium stained most intensely for oxidative enzyme systems, particularly the glucose‐6‐phosphate dehydrogenase system. These areas of high activity were thought to represent apices of supporting cells rather than receptor cells. This localization of a pentose phosphate shunt enzyme system was related speculatively to ion transport in these cells. Alkaline phosphatase was relatively slight in respiratory areas during the ages studied. The basal portions of olfactory epithelium stained positively for alkaline phosphatase. Since hydrolytic enzymes have been thought to be important in the mechanism of olfaction, its demonstration in these tissues suggests that this portion of the olfactory mechanism is present by midgestation in the rodents studied.
Gross anatomy of the blood supply and biliary drainage of the canine liver
Authors: Sleight Douglas R. , Thomford Neil R. 
Published: February 2005

AbstractNecropsy examinations were performed on 100 dogs to study the biliary system, blood supply, and topographic anatomy of the liver. The major ligamentous attachments of the relatively mobile organ are the left triangular and hepatoduodenal ligaments. Considerable fixation is provided by the hepatic veins and the intimate attachment of the liver to the inferior vena cava.The six lobes of the liver are arranged in three natural divisions. The portal vein, its branches, and their distribution are consistent as are major hepatic veins. The hepatic artery branches and major bile ducts have patterns which may be readily related to the divisional boundaries. The branches of the hepatic artery vary in number from one to five. Three branches were present in 64 of 100 specimens. A single gallbladder and cystic duct were found in each of 100 specimens. The common bile duct is formed from three (64%) or four (36%) major collecting or divisional ducts. When four divisional ducts are present, the right and left divisions of the liver are each drained by a single duct with two ducts draining the central division. The cystic duct may join either the right or left central divisional duct to form the common bile duct.
Observations on the ultrastructure of the ectodermal component during odontogenesis in Helostoma temmincki
Authors: Garant Philias R. 
Published: February 2005

AbstractThe role played by the ectodermal component during lower vertebrate tooth development has been a subject of much speculation. In order to provide new information on this matter the cytostructural changes occuring in the ectodermal part of the tooth buds of a small fresh water fish Helostoma temmincki were investigated.The cells of the two epithelial layers which form the ectodermal cap of the tooth bud showed little sign of specialization during the early phase of tooth formation. There was no evidence of the synthesis and secretion of enamel matrix. With the onset of the calcification of the dentin specializations indicating an absorptive activity were observed in the cells of the outer epithelial layer. These changes consisted of an elaborate system of canalicular spaces and coated vesicles. Concurrently the cells of the inner layer accumulated large amounts of iron in the form of ferritin particles. The iron was subsequently deposited over the outer layer of the dentin imparting a reddish‐brown coloration to the teeth.The ultrastructural specialization of the ectodermal component during tooth development are suggestive of transport functions similar to those which are thought to occur in post‐secretory enamel organs during the maturation of enamel.
Histology of the para‐anal sebaceous glandular organs of the bat Eonycteris spelaea (Chiroptera: Pteropidae)
Authors: Quay W. B. 
Published: February 2005

AbstractPara‐anal organs of nine specimens of the rare, Southeast Asian bat Eonycteris spelaea were studied in serial sections by light microscopy. Parenchymal tissue of the organs consists of solid cords of cells budded from the naked epidermis without association with hair follicles. Cytological characteristics and cytomorphosis of para‐anal gland cells differ markedly from those of typical sebaceous glands in adjacent haired skin, and the phases of growth, differentiation and secretion appear to be segregated in time. Nevertheless, holocrine secretory activity and a sebum‐like secretion occur in this highly specialized sebaceous organ. Although found in both sexes, it is larger in adults, in males as compared with females, and in reproductively more active males as compared with males of the same size but with smaller testes.
The presacral component of the visceral pelvic fascia and its relation to the pelvic splanchnic innervation of the bladder
Authors: Roberts W. H. , Taylor W. Holmes 
Published: February 2005

AbstractThe relation of the autonomic nerve supply of the pelvis to the visceral pelvic fascia and in particular that of the parasympathetic supply to the bladder musculature is of particular consequence in pelvic operations. It is observed that the pelvic splanchnics, including those branches supplying the bladder, are embedded in the peripheral component of the visceral pelvic fascia or presacral fascia throughout a considerable part of their course. Early anatomists made no distinction between the presacral fascia and the fascial sheath of the rectum proper. Consequently their illustrations shown only a single fascial layer which they call the “rectal fascia” or “posterior fibrous sheath of the rectum” separating the middle sacral vessels from the superior rectal vessels which lie in the pararectal fat. While such a distinction has since been made in the surgical literature, most anatomical descriptions are still rather vague in this respect. It is essential to develop the plane of cleavage between the presacral fascia and the fascial sheath of the rectum if injury to the pelvic splanchnic nerves is to be avoided.
Embryonic vertebrate central nervous system: Revised terminology
Authors: Angevine Jay B. , Bodian David , Coulombre Alfred J. , Edds Mac V. , Hamburger Viktor , Jacobson Marcus , Lyser Katherine M. , Prestige Martin C. , Sidman Richard L. , Varon Silvio , Weiss Paul A. 
Published: February 2005

AbstractThe layers and cells of the early developing central nervous system lack direct counterparts in the adult and must be designated by a special terminology. The inconsistent and inaccurate language now in use leads to misunderstanding and a revision is proposed in which the four fundamental zones are termed the ventricular, subventricular, intermediate, and marginal zones. Each is defined according to the form, behavior, and fate of its constituent cells. All neurons and macroglia of the central nervous system can be derived from these developmental zones.
Profile analysis of the oviductal wall in rabbits and cattle
Authors: El‐Banna A. A. , Hafez E. S. E. 
Published: February 2005

AbstractTwelve nulliparous New Zealand White female rabbits, and eight nulliparous Hereford heifers were used for profile analysis of the oviductal layers after in vivo and in vitro fixation of the oviducts. The unstraightened oviducts were cut into eight segments of about 1 cm starting from the uterotubal junction. Using a projection microscope, the areas of the lumen, mucosa + submucosa, and musculature of cross sections from each segment were measured planimetrically. The lumen of segments 5 and 6 (from the fimbriae) had the smallest surface area at all reproductive stages in both species. At about 72 and 168 hours after ovulation, the surface area of the lumen at these two segments increased by two‐fold compared to the estrous stage. The ampullary‐isthmic junction (AIJ) is probably located at 6/10 to 7/10 of the oviductal length (segment 5 or 6) in both species. The widening of the lumen at the AIJ, 60–70 hours post ovulation, is sufficient to allow the trapped eggs to pass rapidly to the uterus. The whole isthmus and particularly the AIJ seems to function as a sphincter, the closure of which may be coordinated by neuro‐endocrine mechanisms.
Twinning in the common snapping turtle, Chelydra serpentina
Authors: Yntema C. L. 
Published: February 2005

AbstractTwinning or duplication was observed in 28 eggs of the common snapping turtle, Chelydra serpentina serpentina. The methods of observation made detection of separate blastodiscs relatively certain, that of duplication within a blastodisc less so. Only two of the latter were found. Twins occurred in about 1% of the eggs; 26% of the clutches had one or more abnormal eggs. Twinned blastodiscs developed normally in early stages. When incubated through hatching, 12 out of 12 sets of twins developed unequally so that one was essentially normal, the other was small and not viable. In one case, in which the carapace of the smaller twin was three quarters the length of the larger, both died during hatching. The pigmentation patterns of the carapace of these twins differed; this indicates that they are fraternal rather than identical twins.
Identification of the corticotropin cell in rat hypophyses with peroxidase‐labeled antibody
Authors: Baker Burton L. , Pek Sumer , Midgley A. Rees , Gersten Brian E. 
Published: February 2005

AbstractUtilization of peroxidase‐labeled antibody to porcine corticotropin permitted the delineation of a distinctive cell in the hypophyseal pars distalis of the rat that appears to be the source of corticotropin. Corticotropin cells were stellate and possessed processes that ended on the walls of sinusoids. Corticotropin cells composed a small percentage of the total cell population, and were distributed throughout the gland except that they were less common posteriorly, superiorly, and immediately alongside the pars intermedia. Alteration in size of corticotropin cells was related directly to change in corticotropin content of the gland as effected by differing physiological conditions. Thus, they were larger in the female than in the male and were enlarged after adrenalectomy of the male; they became much smaller following treatment of the female with cortisol. Some corticotropin cells stained with aldehyde fuchsin and the periodic acid‐Schiff (PAS) reaction. These reactions were more intense if hormone antibody and the gamma‐globulin conjugate had been applied previously. However, the capacity of some corticotropin cells to stain weakly with PAS without prior application of antibody suggests that they may contain mucoprotein.
Determination of growth rates by tetracycline‐labelling in guinea pig maxillas
Authors: Soni Narendar N. , Messer Ken B. 
Published: February 2005

AbstractA surface planimeter was used to assess tetracycline‐labelled areas of undecalcified sections of the maxillas of 16 male guinea pigs. In three different molar regions studied, highest values were found in the last‐molar region, followed by the first‐molar and second‐molar region. In the 32–42 day old animals the values in the incisal region were higher than in the first‐and‐second‐molar region, but lower than in the last‐molar region. In the age groups of 47–57 and 62–67 days, proportions of labelled bone in the incisal regions were lower than those found in the first‐molar and last‐molar regions, but approached the level of those found in the second‐molar region. There were statistically significant age‐associated differences and varying amounts of labelled bone in different areas.
Alterations in the morphology of rat liver cells influenced by insulin
Authors: Morgan Carl R. , Jersild Ralph A. 
Published: February 2005

AbstractThe electron microscopic observations of liver cells from normal, fasted, diabetic, and insulin‐treated diabetic rats were compared. The most striking electron microscopic features were the sparsity of glycogen particles in fasted and diabetic rat liver cells and the diminution in lamellar formations of rough endoplasmic reticulum in the diabetic animals. Forty‐one hours of insulin treatment of diabetic rats restored the appearance of liver cell structure to normal. These variations in liver cell fine structure were correlated with circulating insulin levels and previously reported enzyme activities.
Fibrinoid and the fetal‐maternal interface of the rat placenta
Authors: Martinek John J. 
Published: February 2005

AbstractFetal‐maternal interfaces of rat placentas, obtained from midgestation to term, were examined for their content of electron‐dense fibrinoid. Although increased amounts of interfacial fibrinoid were noted as the time of parturition was approached, at no time did fibrinoid form an intact, electron‐dense barrier between the fetal trophoblast giant cells and the maternal decidual cells of the definitive rat placenta. Large areas of apparently viable fetal trophoblast and viable maternal decidua were intimately juxtaposed throughout the latter half of pregnancy. It is concluded that a poorly discontinuous layer of fibrinoid cannot serve as an effective barrier to a proposed flow of transplantation antigens from the fetoplacental unit to the maternal host.
Histochemistry of mucus in the skin of the frog, Rana pipiens
Authors: Dapson Richard W. 
Published: February 2005

AbstractHistochemical characteristics of the integumentary mucous glands of the leopard frog (Rana pipiens) are described so that their role in water balance can be better understood. Mucus is acidic, due to its content of sulfate and carboxylic acids. The carbohydrate moiety contains periodate‐engendered groups which are not in close proximity to acid radicals. Protein was not demonstrated. Neuraminic acid is either absent or is not susceptible to neuraminidase digestion.
Development of peribiliary dense bodies in embryonic rat
Authors: Wood Richard L. 
Published: February 2005

AbstractThe formation of peribiliary dense bodies in developing rat liver was studied by electron microscopy. Dense bodies arise in close conjunction with an extensive Golgi apparatus which displays acid phosphatase, inosine diphosphatase and thiamine pyrophosphatase activity throughout development. The position of these enzymes within the Golgi apparatus appears somewhat variable. Dense bodies are present by the thirteenth day of development and gradually increase in number. They show acid phosphatase activity from their earliest appearance. These findings demonstrate that: (1) peribiliary dense bodies are lysosomal from their earliest appearance; (2) they apparently arise directly from a well‐developed Golgi apparatus; and (3) the Golgi apparatus contains several enzymes simultaneously, suggesting that it becomes multifunctional at an early stage of development.