bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pineal influence on the Harderian glands of female golden hamsters
Authors: Clabough Jeanne W. , Norvell John E. 
Published: February 2005

AbstractThe effects of blinding on cellular structure and porphyrin pigment content were studied in Harderian glands of pinealectomized and non‐pinealectomized adult female golden hamsters. Uterine weights were used as a criterion for pineal activity. Five weeks post‐operatively, no significant changes were observed in the Harderian glands or in the uterine weights of animals in either group. Eleven weeks post‐operatively, the blinded hamsters with intact pineal glands had significantly lowered uterine weights and Harderian glands that exhibited diminished amounts of porphyrin pigments and cellular characteristics of the male hamster. Harderian glands and reproductive organs from the 11‐week blinded‐pinealectomized hamsters did not differ from those of untreated controls.
Quantitative aspects of follicular development in the untreated and PMS‐treated cyclic hamster
Authors: Greenwald Gilbert S. 
Published: February 2005

AbstractHamsters injected at 0900 on day 1 of the cycle (metestrus) with either 0, 5 or 15 IU pregnant mare's serum (PMS) were killed at 1500 of days 1 to 4 of the cycle and the ovaries prepared for light microscopy and for a quantitative evaluation of follicular development. In the untreated cyclic hamster, the maximal number of preantral follicles with eight or more layers of granulosa cells occurred between the afternoon of day 4 (proestrus) and day 1, coinciding with the highest blood levels of FSH and LH. It is concluded that the elevated preovulatory levels of gonadotropins not only induce the ovulation of the mature antral follicles but at the same time recruit the next set of follicles for development during the new cycle.By the afternoon of day 1, treatment with either 5 or 15 IU PMS recruited more follicles into large preantral and incipient antral stages than in the untreated hamsters. However, by day 2 the pattern of follicular distribution was similar between the 5 IU PMS and untreated group whereas considerably more antral follicles had differentiated in the animals given 15 IU PMS. The ability of 15 IU PMS to elicit superovulation therefore depends on the levels being initially high enough to mature more follicles at critical stages of their development; the prolonged biological half life of PMS then sustains these follicles throughout the cycle.
Cytochemical evidence for cation fluxes in parotid acinar cells following stimulation by isoproterenol
Authors: Simson J. A. V. , Spicer S. S. 
Published: February 2005

AbstractThe use of potassium pyroantimonate‐osmium tetroxide as a combined fixative and cation‐capture agent has permitted the observation of finestructural changes in cation distribution in rat parotid acinar cells following administration of isoproterenol (IPR). During the secretory phase of the response, there is a diminution of antimonate‐precipitable cation in the cytoplasm combined with an increase along the plasma membrane and on secretory channels. At four hours after IPR, cytoplasmic precipitates return but deposits disappear along the membrane. Membrane deposits return slowly at later times after the stimulus. Decreased antimonate‐precipitable cation was observed in nuclear heterochromatin between 4 and 20 hours after IPR. This may be related to the induction of cell replication by the drug. During the DNA synthetic phase of the response to IPR, an unusual patchy osmiophobia was observed in nuclei. Mitotic chromosomes contained heavy antimonate deposits. Some of the early changes in cation distribution observed after isoproterenol administration mimicked changes seen in damaged cells.
Ultrastructural changes in vaginal epithelium of mice neonatally treated with estrogen and prolactin
Authors: Mori Takao , Nagahama Yoshitaka , Bern Howard A. , Young Patricia Nelson 
Published: February 2005

AbstractThe vaginal epithelium of the normal estrous mouse shows narrow intercellular spaces, many cytoplasmic fibrils and a continuous basal lamina. At 100 days of age, the vaginal epithelium of mice which had received 5 or 20 μg estradiol‐17β, 20 μg ovine prolactin, or 5 μg estradiol‐17β + 20 μg prolactin within the first few days of postnatal life, shows wider intercellular spaces in the middle epithelial layers than occur in normal estrous mice. In addition, the mice receiving 20 μg estradiol‐17β show prominent intercellular spaces in the basal cell layer and interruptions in the basal lamina, which permit penetration of cytoplasmic processes into the subjacent connective tissue. The relevance of these findings to vaginal carcinogenesis is considered.
The development of the ovary from birth to maturity in the bank vole (Clethrionomys glareolus) and the vole (Microtus agrestis)
Authors: Peters Hannah , Clarke J. R. 
Published: February 2005

AbstractThe postnatal development of the ovary in the bank vole and vole was investigated in order to determine whether the earlier onset of puberty in the vole coincides with a difference in the speed of gonadal development during the immature period in the two species.The ovarian development differed in three respects: in the vole 4–10% of the germ cells are still oogonia when the animal is born, while in the bank vole oocytogenesis is completed during the embryonic period. Follicles develop earlier and more rapidly in the vole than in the bank vole. The early appearance of fluid accumulation in the follicles and the formation of “fluid sacs” in the vole ovary is characteristic.
Ultrastructural changes of rat blastocysts induced by estrogen during delayed implantation
Authors: Wu Jung‐Tsung , Meyer Roland K. 
Published: February 2005

AbstractUltrastructural changes of rat blastocysts during delayed implantation were studied 16, 20, 24 or 30 hours after estrogen was given to induce implantation.In the inner cell mass the presence of long cytoplasmic processes penetrating deeply into the neighboring inner cell mass cells is seen at 16 hours. Most cells also show an increased number of ribosomes, polyribosomes and granular endoplasmic reticulum.The trophoblast is featured by the formation of large amounts of glycogen and many inclusion bodies. Glycogen granules appear first in some abembryonic trophoblast cells at 16 hours, and spread to the embryonic pole at 24 hours. New inclusion bodies appear sequentially: multivesicular bodies at 20 hours, multigranular bodies at 24 hours and lamellar bodies at 30 hours. The functions of these inclusion bodies remain to be studied.
Electron microscopic observations on advanced stages of spontaneous polyspermy in rabbit zygotes
Authors: Gulyas Bela J. 
Published: February 2005

AbstractThe fine structural appearance of eight spontaneously polyspermic rabbit zygotes was studied. The zygotes were considered polyspermic only after they met all criteria that excluded other possibilities of the trinucleate state. The presence of accessory male pronuclei, with varying degrees of disintegration of their chromatin in zygotes of similar age, suggests that refertilization can occur during an interval of several hours after penetration of the primary sperm. All of the polyspermic zygotes contained cortical granules intermittently beneath the vitelline (plasma) membrane. One zygote possessed cortical granule‐like structures with ill‐defined or no limiting membrane. Formation of enveloping membranes around the incorporated accessory sperm head was precocious since it occurred prior to disintegration of the chromatin. Advanced stages of accessory pronuclei morphologically resembled the primary pronuclei in the same zygote. In seven out of eight zygotes the accessory male pronucleus was separated from the apposing male and female pronuclei. It was concluded that although the fully expanded accessory male pronucleus is similar to the pronuclei of monospermic fertilization, the temporal events of nuclear envelope formation were disturbed.
Proprioceptive innervation in the masticatory muscle of Temminck's mole, Mogera wogura (Temminck, 1842)
Authors: Kubota Kinziro , Masegi Toshiaki , Osanai Kentaro 
Published: February 2005

AbstractThis investigation was designed to obtain more anatomical information about the neuromuscular mechanism of the jaw movement by a comparative study of the insectivores. The muscle spindle distribution in the masticatory muscles of Temminck's mole showed a strong similarity to that of the Japanese shrew‐mole. Muscle spindles counted were 174 in number in a restricted area of the jaw‐closing muscles, 92 in the horizontal and 39 in the vertical portion of the temporalis muscle, 18 in the medial pterygoid muscle and 25 in the profound portion of the masseter muscle. The lateral pterygoid muscle, and the jaw‐openers, contained no spindles.
Effect of continuous darkness on diurnal rhythm in glycogen content in pineal cells of the mouse: A semiquantitative histochemical study
Authors: Kachi Takashi , Matsushima Shoji , Ito Takashi 
Published: February 2005

AbstractThe effect of continuous darkness on diurnal variation of glycogen content in pineal cells of adult mice was investigated by means of a semiquantitative histochemical method. In dark‐maintained mice, a diurnal rhythm in pineal glycogen content persisted for the first 7 days of darkness. After 14 days or longer of continuous darkness, however, a clear relationship between the glycogen content and time of day became less apparent. Reversed conditions of environmental lighting caused a complete reversal of the glycogen rhythm in the pineal as early as the fifth day. When mice that had been kept in reversed conditions of lighting for 7 days were exposed to continuous darkness, the reversed glycogen rhythm also persisted in darkness of 7 and 14 days, but it was abolished by darkness of 28 days. The nuclear density of pineal cells was significantly lower at 9 am than at 9 pm in controls. In dark‐maintained mice, however, no significant diurnal variation in pineal cell size was generally evident except 2 and 3 days after the initiation of darkness.
Isolation of viable human muscle spindles for electron microscopic and physiologic study
Authors: Kennedy William R. , Poppele Richard E. , Staley Nancy A. 
Published: February 2005

AbstractHuman muscle spindles are isolated from muscle biopsies of Extensor Indicis. A spindle rich portion of muscle is removed, placed into a modified Kreb's solution and microdissected for spindles. Intramuscular nerves and blood vessels provide helpful locating guides. Spindles can be dissected free of extrafusal muscle with an adequate length of nerve for in vitro recording. Another portion of muscle is stretched and placed into a 5% glutaraldehyde fixative in 0.1 M cacodylate buffer. Spindles are dissected free, postfixed, dehydrated, stained, and then studied with the light microscope while in liquid Epon. The equatorial regions are identified, then removed and embedded for examination using the electron microscope. This is the first successful total isolation of viable human spindles. The combined procedures allow correlation of recordings from the primary sensory endings with the fine structure of spindles from normal persons and from patients with neuromuscular disorders.
Light and electron microscopy of the human fetal thymus
Authors: Haar Jack L. 
Published: February 2005

AbstractThe human fetal thymus was studied at stages from 9 to 20 weeks of gestation. At 9 weeks of gestation the human fetal thymus contained lymphoid cells and was vascular although it was not yet lobulated nor did it have a cortex and medulla. By 12 weeks the thymus was lobulated and at 14 weeks a cortex and medulla could be distinguished, although the medulla was often more densely cellular than the cortex. By 18 weeks there were many lobules and a mature looking cortex and medulla. Large lymphocytes at all stages of thymus development studied were irregular in shape and often had blunt pseudopodia‐like cytoplasmic extensions, or more slender cytoplasmic extensions. They also often possessed numerous elongated mitochondria, a large Golgi complex and strongly basophilic cytoplasm. Large lymphocytes were not attached to the epithelial cells by desmosomes although some of the cytoplasmic extensions from them were in association with extensions from epithelial cells. Primitive medium‐sized lymphocytes at all stages studied were round in shape and had fewer mitochondria than the large lymphocytes. Epithelial cells were much less basophilic than the lymphoid cells and usually contained aggregates of glycogen. Occasional macrophages were observed within the developing thymus after 12 weeks of gestation and one granulocyte was observed within the thymus at 9 weeks while numerous granulocytes were seen within an interlobular septa at 14 weeks of gestation. Vessels were present within the thymus at all stages studied and at 9 weeks some had a boundary between the blood and thymus which consisted of only a thin endothelial cell and its basal lamina rather than the usual boundary of an endothelial cell and its basal lamina plus an epithelial cell and its basal lamina.
Ultrastructure of terminal pulpal blood vessels in mouse molars
Authors: Corpron Richard E. , Avery James K. , Lee Soo D. 
Published: February 2005

AbstractThe purpose of this investigation was to study the fine structure of pulpal capillaries located in the odontoblastic layer and immediate subjacent zone. The observations were from first molars of white mice sacrificed at five day intervals from 25–90 days. Both capillaries and small vessels with an incomplete smooth muscular coating appeared in the zone subjacent to the odontoblastic layer from 25–60 days. At the same time, capillaries which exhibited intracellular fenestrations in the endothelial wall were located within the odontoblastic layer.From 50–90 days, the capillaries among odontoblasts, especially at the pulpal horns, appeared close to the predentinal surface, and an isolated capillary appeared to extend into predentin and run parallel to the outer surface of the odontoblastic layer for a short distance. At these ages, the capillaries subjacent to the odontoblastic layer also exhibited fenestrations along the thin endothelial walls similar to those observed at earlier ages in capillaries among odontoblasts.
Lighting regimen dominates interacting meal schedules and synchronizes mitotic rhythm in mouse corneal epithelium
Authors: Scheving L. E. , Pauly J. E. , Burns E. R. , Halberg F. , Tsai S. , Betterton H. O. 
Published: February 2005

AbstractThree groups of mice were standardized to a light‐dark cycle with light from 0600 to 1800. One group was fed ad lib; but the other two had access to food for only four hours a day, one during the first part of the light phase and the other beginning at its middle. Two other groups were subjected to a reversed light‐dark cycle (light from 1800 to 0600); one of these had access to food for four hours during the first part of the dark phase and the other for four hours beginning at its middle. All the mice previously had been adjusted gradually over a three‐week period to these feeding schedules, and then they were maintained on the precise routine described for an additional two weeks. After standardization was completed, subgroups of mice were killed at three‐hour intervals over a single 24‐hour period. Corneas were removed and prepared, and the mitotic index in the epithelium was evaluated.In all five groups a high‐amplitude circadian rhythm was found for the mitotic index, but in all cases this rhythm remained synchronized to the light‐dark cycle; only small changes in the phasing of the rhythm resulted from the restricted feeding. These results are contrary to what has been found for a number of other rhythmic variables which do synchronize to such feeding schedules.The findings dispel the misconception that all body functions react in the same fashion to different synchronizors and emphasize that one must not generalize about the effects of feeding or lighting.
Comparative analysis of surface charges on luminal epithelial membranes of urinary bladders from toad, frog, turtle, and tortoise
Authors: Danon David , Ekblad E. B. Margareta , Strum Judy M. 
Published: February 2005

AbstractCationized ferritin was used to analyze the surface charges on the luminal epithelial cell membranes of urinary bladders from toad (Bufo marinus), bullfrog (Rana catesbiana), turtle (Pseudemys scripta and Clemmys caspica), and tortoise (Geochelone carbonaria and Testudo graeca). The labeling, done at a physiological pH on fixed or unfixed bladders, revealed differences in the distribution and density of negative charges along the luminal membrane surfaces. The epithelial surface of toad bladder did not label with cationized ferritin. Frog bladder labeled lightly and the labeling pattern varied between cell types. The epithelial membrane surfaces of reptile bladders were heavily labeled, in contrast to amphibian bladders. Luminal surfaces from fresh water turtles were not as heavily labeled as those from land tortoises. The degree of labeling varied from cell type to cell type in all reptile bladders except Pseudemys scripta. An analysis of the degree and pattern of labeling by cationized ferritin in bladders of all species studied might reflect a difference in the nature of the glycocalyx of a particular membrane, the presence or absence of negative surface charges or their availability (i.e., interference by mucus), and/or the nature of the chemical groups comprising the surface structure of the membrane.
Some ultrastructural and cytochemical features of fiber populations in the soleus muscle
Authors: Gauthier Geraldine F. 
Published: February 2005

AbstractThe soleus muscle is widely used in biochemical and physiological investigations as an example of a slow‐twitch red muscle, and it has been assumed, for the most part, that it consists of a homogeneous population of either red or intermediate fibers. In the present study, the cytological composition of this muscle was examined in four commonly studied species, namely the rat, guinea pig, rabbit and cat. Using the form and distribution of mitochondria as the principal criteria for identification, two distinct types of muscle fibers can be recognized in the soleus of the guinea pig and rabbit as well as the rat. The soleus muscle is therefore not homogeneous in either species. Preliminary observations suggest that the soleus of the cat is likewise not homogeneous. In addition, although the fibers resemble red and intermediate fibers in other skeletal muscles, the resemblance is only superficial. In the two fiber types of the rat and guinea pig soleus, the Z line is characteristically wide, and therefore, based on this criterion, the fibers are not equivalent to either the red or intermediate fibers of other muscles.
The organization of the seminiferous epithelium in the mouse testis following ligation of the efferent ductules. A light microscopic study
Authors: Ross Michael H. 
Published: February 2005

AbstractSeminiferous tubules from mouse testes were studied with the light microscope after the efferent ductules had been ligated for 48 hours. As a consequence of ligation, the tubules became markedly distended by the fluid which they accumulated; the epithelium was reduced in height, and exhibited a significantly less complex stratification than in the normal. Longitudinal sections of the distended tubules, particularly those in the early stages of the seminiferous cycle, revealed pillar‐like epithelial profiles arranged in a repetitive series. Each “pillar” consisted of Sertoli cell cytoplasm along with two generations of spermatids, the older generation embedded within the Sertoli cell, and the younger generation aligned, one cell above the other, along its sides. Oblique or grazing sections through tubules exhibiting the same stages of spermiogenesis revealed band‐like epithelial profiles arranged in parallel array. The two types of epithelial configurations are interpreted as representing a series of circumferentially oriented ridges within the tubule. It is postulated that each spermatid generation within a ridge constitutes a single clone, and that it is the cytoplasmic bridges joining the spermatids, in combination with their attachment to the Sertoli cells, which provide the organization, delineation, and structural stability of the ridges.
Perinatal changes in size of pancreatic acini in the rat with special reference to effects of fetal decapitation and fetal or neonatal oral administration of water or milk
Authors: Morikawa Yoshio , Arishima Kazuyoshi , Eguchi Yasunobu , Hashimoto Yoshiyuki 
Published: February 2005

AbstractNormally, the size of pancreatic acini is remarkably decreased after birth in the rat.Administration of water or milk on day 21 of gestation resulted in decreased acinar size a day later in intact fetuses and in fetuses decapitated immediately after administration of water or milk. The same treatments of premature newborn rats obtained by Caesarean section on day 22 of gestation induced similar effects a day later On the other hand, in starved Caesarean newborn rats, there were no histologic changes in acini. In spontaneous newborn rats which were allowed to suckle maternal milk and then starved for one day, there was an increase in acinar size as compared with that of 2‐day‐old normal rats.These results suggest that the fetal pancreatic acini at least near term (on day 21 of gestation) can respond to some signals conveyed from digestive tracts which have responded to exogenous stimuli, that the brain during fetal days does not play any role in digestive tract‐pancreatic acini interrelations in secretion of zymogen granules and that the neonatal decrease in acinar size is caused by the intake of maternal milk.
Lipid droplet accumulation in cardiac muscle cells of the bat: Potential auto‐toxicity of the cardiac sympathetic innervation
Authors: Nunez Eladio A. , Hagopian Martin , Gershon Michael D. 
Published: February 2005

AbstractThe previously described ability of reserpine and parachlorophenylalanine to induce the accumulation of lipid droplets in ventricular cardiac muscle cells of the bat was investigated. Lipid droplet accumulation was assessed qualitatively by light microscopy and quantitatively by morphometric analysis of electron micrographs. An hypothesis that the action of the drugs was an indirect one, mediated by the cardiac adrenergic innervation, was framed and tested. Lipid droplet accumulation occurred during a time of intense sympathetic activity, that of arousal from hibernation. The ability of the two drugs to produce the effect was antagonized by prior sympathectomy with 6–dopamine. The effect was mimicked by administration of exogenous norepinephrine together with inhibitors of its catabolic enzymes, monoamine oxidase and catechol‐omethyl transferase. These observations are all consistent with the initial hypothesis and raise the possibility that endogenous norepinephrine in the cardiac sympathetic innervation might be, at least potentially, auto‐toxic.