bluuebunny/crossref_metadata_2025_split huggingface dataset:
Early embryonic development and preimplantation changes in the uterus of the bat Rhinopoma hardwickei hardwickei (Gray) (Rhinopomatidae)
Authors: Karim K. B. , Fazil Mohammad 
Published: February 2005

AbstractRhinopoma hardwickei hardwickei has an annual reproductive cycle. Although many of the females become inseminated from the latter half of February until about the middle of April, ovulation has not been recorded until the 11th of March. A single follicle reached full development and released one ovum from either of the ovaries with nearly equal frequency, and a single conceptus was carried in the ipsilateral uterine cornu during each cycle. The embryo descended into the uterus as an early morula and attained the bilaminar blastocyst stage before undergoing implantation. As the morula advanced in age, the embryonic surface of the zona became progressively more basophilic. Hence in advanced morulae, the inner surface of the zona pellucida took a dark stain with hematoxylin and appeared like a distinct thin membrane, while the rest of the thickness of the zona was eosinophilic.Although progestational changes commenced in both uterine cornua, they became augmented in the uterine cornu on the side of ovulation and blastocyst attachment. After blastocyst attachment, the contralateral cornu reverted to an anestrus condition. The progestational changes became less conspicuous from the cranial to the caudal end of the uterus. Evidently, there was a linear gradient in the progestational response of the uterus with the cranial end being most responsive and the caudal end least responsive. The precise mechanism which brings this about is not known.
Reproductive biology of the male little mastiff bat, Mormopterus planiceps (Chiroptera: Molossidae), in Southeast Australia
Authors: Krutzsch Philip H. , Crichton Elizabeth G. 
Published: February 2005

AbstractThe anatomy, biology, and chronology of reproduction in the male of the long penile form of Mormopterus planiceps was studied in southeast South Australia and Victoria. In the morphology of its primary and accessory reproductive organs, M. planiceps was generally reminiscent of other Molossidae; however, in the specialized (sebaceous) nature of the Cowper's gland ducts, in the presence of para‐anal glands, and in the unusual, horizontally bifid glans penis and the greatly elongated os penis, it was distinct from other Molossidae studied to date.Young of the year were not reproductively active. Adults displayed a single annual spermatogenic cycle that commenced in spring (September/October) and culminated in spermiogenesis in autumn (February‐May), during which period plasma levels of testosterone overtook androstenedione. Thereafter, spermatogenesis appeared to cease (though scattered sperm were seen in the seminiferous tubules until August), but abundant epididymal sperm reserves persisted until September/(October). The accessory glands were hypertrophied during this period, becoming involuted by October.Although the numbers of animals available for study were small, these observations, together with the appearance of spermatozoa in the ductus deferens in August/September suggested that mating could occur during the interval from autumn to spring. Late winter/spring insemination is normal for molossids from temperate environments. However, protracted spermatogenesis commencing in spring that is not accompanied by the availability of spermatozoa until autumn, and a subsequent apparent extension of fertility (epididymal sperm storage, accessory gland hypertrophy) beyond the testicular gametogenic phase, are aspects of the male reproductive cycle in M. planiceps that have not heretofore been described in another molossid bat.
Reproductive biology of the female little mastiff bat, Mormopterus planiceps (Chiroptera: Molossidae) in Southeast Australia
Authors: Crichton Elizabeth G. , Krutzsch Philip H. 
Published: February 2005

AbstractThe reproductive biology of the female little mastiff bat (Mormopterus planiceps) was studied from specimens obtained throughout the year in southeast Australia, within the region occupied only by the long penile form of this species.Mormopterus planiceps appeared to undergo a single pregnancy each year and was monotocous. Conception occurred during late winter/early spring after a protracted proestrus, during which the uterine/vaginal epithelia attained an extraordinary thickness; spermatozoa were present in the uterine corpus, vagina, and intramural oviduct for at least 2 months prior to ovulation, although only those present in the oviducts were entire and thus appeared to be viable. Following ovulation, a massive postovulatory infiltration of phagocytes occurred; and the thickness of the uterine corpus epithelium was dramatically reduced. As in other molossids, the tract was bicornuate and dextrally functional.The length of gestation was difficult to determine because early embryonic stages, up to implantation, appeared to span several months (late July/August/September) as did parturition (December/January). Growth of the young was slow; nevertheless, females attained sexual maturity in their first year.Several unusual features included the presence of a long os clitoridis, and tubuloalveolar sudoriferous and associated lobulated, sebaceous, paravaginal glands, which surrounded and emptied into the lower vagina. A deep fornix anterior and lateral to the cervix probably serves to receive the secondary glans penis. The epithelium of the uterine corpus was stratified and indistinguishable, in its cytology and cyclicity, from that of the vagina; furthermore, it lacked a glandular endometrium. This portion of the female tract likely receives the elongated primary glans.These findings are discussed in relation to other Molossidae and to the reproductive biology of male M. planiceps. Although the number of animals sampled was relatively small, the data suggest that this species does not exhibit the usual temperate molossid pattern of late winter/spring coincidence of spermatogenesis and ovulation. It would seem that pregnancy may begin, at least in some individuals, during the inhospitable winter months (when epididymal and uterine spermatozoa are abundant but spermatogenesis has largely terminated) and that additional conceptions continue into the early spring. The occurrence of sperm storage in both sexes of this species is unique among Molossidae studied to date.
Synthesis and transport studies of the intrasyncytial lamina: An unusual placental basement membrane in the little brown bat, Myotis lucifugus
Authors: Cukierski Mark A. 
Published: February 2005

AbstractThe chorioallantoic placenta of Myotis lucifugus undergoes a transition from endotheliochorial to hemochorial. The original maternal endothelial basement membrane is incorporated into the apical portion of the syncytial trophoblast, where it persists until term. This intrasyncytial lamina is separated from the maternal blood by thin ectoplasmic projections of the syncytial trophoblast that project through the lamina and spread over the surface, completely engulfing it. While there appear to be direct channels, at junctions of the ectoplasmic processes, from the maternal blood to the intrasyncytial lamina, perfusion studies using the electron‐dense tracers alcian blue, ruthenium red, and Thorotrast show that these channels are physiologically closed. In contrast, lanthanum nitrate was able to gain access to the lamina via the extracellular channels. The endocytic uptake of the tracers was similar. These studies suggest several pathways for substances to cross the ectoplasmic zone and the intrasyncytial lamina. Substances may gain direct access to the lamina via extracellular channels, reach the lamina by vesicular transport, or bypass the lamina completely through fenestrations within the lamina. Autoradiographic studies show that the syncytial trophoblast synthesizes portions of the intrasyncytial lamina, demonstrating its partial fetal origin. How long the original maternal components persist and the functional significance of the intrasyncytial lamina are unknown. Possible functions of the lamina include increased surface area of the apical plasmalemma, selective filtration, structural support, and maintenance of cell polarity.
Annual skeletal changes in the little brown bat, Myotis lucifugus lucifugus, with particular reference to pregnancy and lactation
Authors: Kwiecinski Gary G. , Krook Lennart , Wimsatt William A. 
Published: February 2005

AbstractStudies of bone from summer‐active little brown bats, Myotis lucifugus lucifugus, have demonstrated sex differences in the renewal of skeletal mineral reserves following spring‐arousal from hibernation. Patterns of bone remodeling in both sexes of bats indicate that new bone formation does not occur during hibernation: All new bone formation occurs during the summer‐active season. Results show that a short period of time elapses after hibernation before the initial demands of a large fetus and rapidly growing neonate are expressed on maternal skeletal reserves. Bone loss in summer‐active females was associated with pregnancy and lactation, whereas summer‐active males did not show evidence of bone loss but, instead, uninterrupted bone accretion throughout the summer‐active season. Osteoclasts and bone‐forming osteoblasts, absent during the hibernation period, reappeared on bone surfaces following spring‐arousal from hibernation. There was no apparent increase in osteoclast numbers or activity during lactation but resorption cavities were found in deep cortical lamellae distant from bone surfaces. The increase in bone resorption in lactating bats appeared to be by osteocytic osteolysis, suggesting that it might be a significant mechanism of bone/calcium regulation in this hibernating mammal throughout the year.
Morphology of thyroid C‐cells and parathyroid glands in summer‐active little brown bats, Myotis lucifugus lucifugus, with particular reference to pregnancy and lactation
Authors: Kwiecinski Gary G. , Wimsatt William A. , Krook Lennart 
Published: February 2005

AbstractMorphological studies of thyroid C‐cells and morphometric analyses of parathyroid glands in summer‐active little brown bats indicated concomitant regulatory endocrine functions correlating with bone remodeling. C‐cells apparently maintain maximal activity throughout the summer‐active period in all bats. However, the hyperactivity of the parathyroid glands in summer‐active female bats can be correlated with the maintenance of plasma calcium concentrations during lactation, when the female skeleton undergoes a period of bone demineralization. In summer‐active male bats, which did not lose bone, the parathyroid glands did not show morphological evidence of hyperactivity; instead they were found to exhibit moderate parathyroid activity.
Presence of abundant filaments in apical caps of the nonciliated bronchiolar epithelial (Clara) cells
Authors: Sasaki Junzo , Takehara Yoshiki , Fujii Yoshitaka , Nomura Takako , Watanabe Sadahiro 
Published: February 2005

AbstractThe nonionic detergent Triton X‐100 has often been used for the extraction of cytoplasmic materials. We used the detergent in a vascular perfusion medium when preparing rat lung in order to observe the cytoskeleton of the nonciliated bronchiolar epithelial (Clara) cells. To eliminate some cytoplasmic materials selectively and to maintain good fine cell structure simultaneously, the lungs were perfused sequentially with the detergent (0.2% Triton X‐100) alone for 2 min, with a mixture of low‐concentration (0.1%) glutaraldehyde and detergent (0.2% Triton X‐100) for 15 min, and finally with 2.5% glutaraldehyde for 5–10 min. After fixation, the nonciliated bronchiolar epithelial (Clara) cells were observed by scanning and transmission electron microscopy. At the apical region of the cells, there were central cytoplasmic protuberances (apical caps) filled with microfilaments. These filaments were bound at one end to the cytoplasmic side of the cell membrane and ran into the interior of the cytoplasm at the other end. As a control, the Clara cells were observed by transmission electron microscopy after perfusion with 2.5% glutaraldehyde solution. The luminal surfaces of the cells were covered with short, thick microvilli. The apical caps also had microvillus‐like protrusions.These results suggest that the apical cap is not an apocrine droplet but rather is a stable structure involved in the function of the Clara cells.
Enzyme histochemistry of the rat nasal mucosa embedded in cold glycol methacrylate
Authors: Randall Holly W. , Bogdanffy Matthew S. , Morgan Kevin T. 
Published: February 2005

AbstractThe nasal passages are anatomically complex, and while there have been a number of descriptions of nasal structure in many species, there is very little information available on the distribution of enzymes in the nasal mucosa. In rodents, this delicate mucosa is the first site within the respiratory tract to be exposed during inhalation toxicology studies designed to assess human risks from such exposures. However, the nasal mucosa presents problems for his‐tologic preparation because it is encased in brittle bones. Because of recent interest in the nose as a target site, and findings from biochemical studies which indicate that the nose is very active metabolically, studies were carried out to determine the value of cold glycol methacrylate (GMA) processing for localization of nasal enzymes. For these studies, liver and kidney were used as positive controls. Published histochemical procedures for acid and alkaline phosphatase, adenosine triphosphatase, glucose‐6‐phosphatase, gamma‐glutamyl transpeptidase, and naphthyl butyrate esterase were applied, with modifications, to undecalcified nasal passages of Fisher‐344 rats. Frozen sections exhibited excellent enzyme preservation but very poor morphology, while GMA gave good enzyme preservation and excellent morphology. For GMA, acetone fixation generally resulted in the best preservation of enzyme activity. It was concluded that cold GMA processing provides a useful approach to studies of nasal enzyme distribution and that this technique of value for inhalation toxicology studies. Details of enzyme distribution in the squamous, respiratory, and olfactory epithelia, associated glands, and other structures of the nose of the rat are described and discussed.
Immunocytochemical localization of oxytocin and neurophysin in human corpora lutea
Authors: Khan‐Dawood Firyal S. 
Published: February 2005

AbstractCorpora lutea, corpora albicantia, and ovarian stroma from normal human premenopausal ovaries were examined for the presence of oxytocin and neurophysin by using highly specific antisera and peroxidase‐antiperoxidase light‐microscopic immunohistochemistry. Oxytocin and neurophysin immunoreactivity was found in some but not all cells of the corpora lutea obtained on days 19 to 24 of the menstrual cycle. Stromal tissue and corpora albicantia did not give a positive reaction for either of these peptides, and negative results were also obtained with corpora lutea of mid‐ and term‐pregnancy and preovulatory follicles. Specificity of the immunohistochemical reaction was confirmed by immunoabsorption tests. The specific localization of immunoreactive oxytocin and neurophysin in corpora lutea of the human menstrual cycle directly demonstrates the presence of oxytocin‐ and neurophysin‐positive cells within the human corpus luteum.
Neuronal and synaptic organization of the outer plexiform layer of the pigeon retina
Authors: Mariani Andrew P. 
Published: February 2005

AbstractThe organization of the outer plexi‐form layer (OPL) of the pigeon retina is described by electron microscopy and Golgi impregnation. Six types of photoreceptor, four types of horizontal cell, eight types of bipolar cell, and an interplexiform cell type were found by Golgi impregnation. The OPL was tri‐stratified due to the endings of the photoreceptors at three different levels. This stratification was reflected in the laminar arrangement of the dendrites of the horizontal and bipolar cells. Electron microscopy showed that the synaptic endings of the photoreceptors made ribbon synapses, both triads and dyads, and basal junctions with the process of second‐order neurons. Horizontal cells formed conventional chemical synapses, while horizontal cell axon terminals were extensively linked by gap junctions.
Two types of chloride cells in the gill epithelium of a freshwater‐adapted euryhaline fish: Lebistes reticulatus; their modifications during adaptation to saltwater
Authors: Pisam M. , Caroff A. , Rambourg A. 
Published: February 2005

AbstractTwo types of chloride cells were identified in the gill epithelium of freshwater‐adapted guppies. One type, referred to as an “α‐chloride cell,” was a pale, elongated cell located at the base of the secondary lamella in close contact with the arterioarterial pillar capillaries. In its cytoplasm, membranous tubules in continuity with its basolateral plasma membrane formed an extended tridimensional network. The vesiculotubular system (Pisam: Anat. Rec. 200:401–414, 1981) consisted of a few tubules and vesicles located next to the apical plasma membrane. A second type, referred to as a “β‐chloride cell,” was a darker, ovoid cell located in the interlamellar region of the primary epithelium facing the central venous sinus. Membranous tubules in continuity with the basolateral plasma membrane were unevenly distributed in the cytoplasm. A prominent vesiculotubular system composed of numerous vesicles and tubules was found between the Golgi apparatus and the apical surface. During seawater adaptation, the α‐chloride cells increased in size and progressively transformed into characteristic “sea‐water α‐chloride cells” with a well‐developed, regular, tight tubular network and numerous vesicles and tubules of the vesiculotubular system accumulated below the apical pit. The α‐chloride cells underwent a progressive degeneration and disappeared. Thus, in freshwater‐adapted guppies, there are two types of chloride cells, α and β, respectively, related to the arterial and the venous vessels, whereas in seawater‐adapted fishes, a single type of cell, the α‐chloride cell, was related to both the arterial and venous channels.
Morphological features of five neuronal classes in the gerbil lateral superior olive
Authors: Helfert Robert H. , Schwartz Ilsa R. 
Published: February 2005

AbstractFive morphologically distinct classes of neurons can be identified within the neuropil of the gerbil lateral superior olivary nucleus (LSO) by using a variety of histological techniques and electron microscopy. The physical features of these five classes resemble those found in the cat LSO and are identified, by using criteria and nomenclature established for the cat, as principal neurons, multiplanar neurons, marginal neurons, small neurons, and class 5 neurons.Principal cells compose ∼ 75% of the total LSO neuronal population. They possess a discoid dendritic organization and are oriented rostrocaudally, perpendicular to the transverse curvatures of the LSO. Roughly 8% of the LSO population is composed of multiplanar neurons, whose dendritic fields are not restricted to any single plane of section. Both principal and multiplanar neurons share similar cytoplasmic features, and >65% of their perikaryal suface is in contact with synaptic terminals. Small neurons compose ∼ 11% of the LSO nerons, have the lowest percentage of their somal surface contacted by synaptic terminals (∼8%), and are found mostly in the middle/medial portions of the LSO. Marginal neurons, which compose ∼6% of the LSO population, appear similar to principal neurons at the light microscopic level except that they are found along the contours of the LSO, oriented orthogonal to principal neurons. Approximately 28% of the somal surface of marginal neurons is in contact with synaptic terminals. The class 5 neuronal somata receive a similar number of axosomatic synaptic contacts as marginal neurons (∼31%) but are found well within the matrix of the LSO, aligned parallel to principal neurons. Class 5 neurons share the same light microscopic features as principal neurons and can be identified electron microscopically based only on the reduced percentage of somal surface occupied by synaptic terminals.
Cytoplasmic bar‐like structures of alveolar type II cells: An ultrastructural study in freshly isolated cells from rat lungs
Authors: Vincent Renaud , Nadeau Denis 
Published: February 2005

AbstractBar‐like structures are tubular cytoplasmic inclusions foundin situin pulmonary epithelial type II cells of several animal species. The physiological significance and mode of formation of these inclusions are not fully established. In this paper, we describe bar‐like structures as found in freshly isolated type II cells from rat lungs. Pulmonary cells were dissociated from the tissue with elastase and separated on a discontinuous density gradient of Percoll. The complete isolation procedure yielded 17 × 106type II cells per animal (purity = 80%). Either from the crude cell suspensions or the purified preparations, only a small fraction of the type II cell population harbored the inclusions (> 5%). It is shown that the bounding membranes of the bar‐like structures can derive from the endoplasmic reticulum, the nuclear membrane, or the Golgi apparatus. Occasional connections with lamellar bodies were observed, and different levels of complexity in the bar‐like structures were also found. The apparent rigid conformation and the orientation of the bar‐like structures were taken as evidence for a role of the cytoskeleton in their formation. Because the inclusions do not appear to be new organelles or cellular structures performing a specific function, we propose that their formation may be a transient and limited cellular event in normal cells. However, the stabilization and the generation of the osmiophilic structures, as well as their overproduction, may reflect alterations of the normal physiology of the type II cells.