bluuebunny/crossref_metadata_2025 huggingface dataset:
The correlation between craniofacial and long bone growth: An experimental investigation in normal rabbits
Authors: Alberius Per , Isberg Per‐Erik
Published: February 2005

The present study was undertaken to elucidate the relationships between craniofacial and long‐bone growth. Nine male New Zealand white rabbits received spherical tantalum bone markers in the tibial epiphyses and in the nasal, frontal, and parietal bones. The animals were followed from 30 to 143 days of age. Growth changes were calculated with a roentgen stereometric system, and the results statistically evaluated. Except for the final interval when all variables varied at random, high correlations between tibial and frontonasal or coronal sutural growth were demonstrated; and the respective linear regression lines were homogenously assembled. The relationship between the tibia and the sagittal suture displayed great variations between individual animals as well as between the suture's parts, although growth at the interfrontal suture was clearly correlated to tibial growth upon exclusion of the time factor. The first principal component of the three neurocranial sutures was calculated and seemed accurately correlated to longbone growth. The present study concluded that growth at the frontonasal and coronal sutures normally seems to parallel general somatic development, while growth at the sagittal suture appears individually displaced in time. Nevertheless, when the principal component of the combination of the coronal suture and the neurocranial section of the sagittal suture was computed, this was highly correlated to body growth.
Intraventricular neuronal complex of the lamina terminalis of the mouse
Authors: Bleier Ruth , Siggelkow Inge
Published: February 2005

An intraventricular neuronal complex has been identified with scanning and transmission electron microscopy at the base of the lamina terminalis of the mouse. The raspberry‐shaped complex protudes from a thickened bulge on the ependymal surface of the lamina terminalis or adjacent rostral floor of the third ventricle. Neurons and occasional ependymal cells cover the surface of the complex. Its core is made up of neurons, ependymal cells, and neuronal processes, which are usually compactly arranged. The core is continuous, through a breach in the ependymal layers, with the subependymal neuropil of the lamina terminalis. Within the core of the complex are large numbers of axodentritic synapses. Axonal varicosities and synaptic terminals are filled with vesicles and mitochondia. Synaptic endings have one of two populations of vesicles: exclusively clear, small, round or flattened vesicles. In view of the known structural and functional characteristics of the lamina terminalis, it is possible that the neuronal complex may participate in neurohormonal regulatory systems of the hypothalamus and hypophysis or in the network of circumventricular organs mediating angiotensin effects.
Circular polysomes predominate on the rough endoplasmic reticulum of somatotropes and mammotropes in the rat anterior pituitary
Authors: Christensen A. Kent , Kahn Larry E. , Bourne Carol M.
Published: February 2005

We have studied the shape and size distribution of membrane‐bound polysomes in somatotropes and mammotropes, which are the sources, respectively, of growth hormone and of prolactin in the rat pituitary. The observations were made in conventional electron micrographs of these cells in situ, where occasional surface or en face views of the rough endoplasmic reticulum allow the polysomes to be seen as rows of ribosomes arranged in distinctive patterns on the membranes. It is possible by this means to characterize the shape and number of ribosomes for the total population of bound polysomes in the respective cell types.

The great majority of membrane‐bound polysomes in these two cell types (81% in somatotropes, 78% in mammotropes) have an approximately circular shape and contain an average of 6.8 (somatotropes) or 6.5 (mammotropes) ribosomes, which is an appropriate size for translation of the polypeptide hormones produced by these cells. About 17% of the membrane‐bound polysomes in somatotropes and 20% in mammotropes have a spiral shape, resembling somewhat the letter “G,” and contain about eight to nine ribosomes in both cell types.

The preponderance of circular polysomes on the rough endoplasmic reticulum of somatotropes and mammotropes suggests the possibility that ribosomes (or the 40S ribosomal subunit) may recycle on the polysome after the translation of growth hormone or of prolactin.
Ultrastructure of the choroid plexus epithelium of pigeons treated with drugs. II. Effect of cytochalasin D and colchicine
Authors: Koshiba Kimikazu
Published: February 2005

A remarkable projection of bleblike protrusions, the expulsion of organelles into the protrusions formed on the apical surface, and the separation into the ventricular lumen of these protrusions was the general cellular response of choroidal epithelial cells to intravenous injection of cytochalasin D (CD). The compact microfilament mass and agglomeration of microtubules at the base of the cluster of protrusions reflect the results of cell contraction and displacement of microfilaments induced by CD.

In earlier stages after intravenous injections of colchicine, an obvious increase in the number of varioussized vesicles, vacuoles, and lysosomes in the Golgi region was detected. In the later stages, these organelles were seen to accumulate in the basal portion of the epithelial cells. These changes were accompanied by an increase in vacuoles and the disorganization and displacement of the Golgi complex, and they coincided with a decrease in the number of microtubules in apical and basal cytoplasm. These findings suggest that the action of colchicine results in destruction of the three‐dimensional architecture between cytoskeletal network and cell organelles.

The present results suggest that the cytoskeletal network plays a role in the spatial coordination of the three‐dimensional architecture of cell organelles. The study also indicates that the structural differences in the ventricles of the choroid plexus in drug‐treated pigeons are manifestations of regional functional specialization in different parts of the ventricular system.
Lung growth of the turkey, Meleagris gallopavo: II. Comparison of two genetic lines
Authors: Timmwood K. I. , Hyde D. M. , Plopper C. G.
Published: February 2005

Comparisons of lung growth in two genetic lines of turkeys, one unselected and one selected for increased body mass, were used to evaluate the lung's alteration in structure with changes in body form or physiology. Seventy‐two male turkeys, 36 genetically selected for early rapid growth and large pectoral musculature, and 36 unselected birds, were killed at 12 different ages to compare lung growth in the two lines. Body weights and lung volumes were determined. A three‐level cascade sampling system was used to prepare lung tissue for qualitative and quantitative observation by light microscopy. Allometric equations describing growth of lung volume and lung compartments relative to body weight in two phases (tissue proliferation and equilibrated growth) were compared between lines of turkey for differences in slopes or intercepts. Means of data for 112‐ and 420‐day‐old birds were also compared.

There were no qualitative histological differences observed between lungs of the two lines of turkey, yet there were morphometric differences in lung growth relative to body weight. During equilibrated lung growth, there was less rapid growth of air and blood capillary volumes and surfaces relative to body weight in the selected than in the unselected turkey. The gasexchange compartment did not enlarge concomitant with the large increase in muscle mass of the selected turkeys, while large‐vessel volume and small‐airway volume grew similarly to body weight in both turkey lines. We conclude that the lung of the selected line of turkeys did not show an enlarged gas‐exchange compartment relative to the greater body muscle mass, but it did show enlarged vessels and conducting airways.
Circadian modification of ethanol damage in utero to mice
Authors: Sauerbier Ingrid
Published: February 2005

This study evaluates the ethanol toxicity for fetal development at different circadian stages. Pregnant mice were given a single intraperitoneal ethanol injection on day 7, 8, or 10 of gestation at one of four circadian stages (0700, 1300, 1900, or 0100 hr). The dams were killed on the day before term (day 18). Prenatal exposure to ethanol resulted in an increased number of resorptions, reduced fetal body weight, and produced an increased incidence of external alterations. The severity of damage was related to the dose, the period of gestation, and particularly to the circadian stage at the time of treatment. Ethanol had the greatest effect on the embryo of a mouse when administered at the mid‐dark span. Consequently exposure to a single dose of ethanol at one time or another along the 24‐hr time scale during organogenesis has important implications for the substantially increased risk.
Structure and growth activities of the mandibular condyle in monkeys (Macaca fascicularis): II. Synergistic behavior of cell dynamics and metabolism
Authors: Luder H. U.
Published: February 2005

The mandibular condyles of eight growing male monkeys (Macaca fascicularis) were analyzed by using a combination of radioautographic and morphometric techniques. This was done with the aim of examining the dynamics in the structure and growth activities of the articular tissue covering as well as of the subchondral zone of erosion. The animals received 1 mCi/kg body weight 3H‐proline 24 hr and 0.5 mCi/kg body weight 3H‐thymidine 3 hr prior to death. Their age was estimated on the basis of skeletal maturation as recorded from radiographs of the hand and wrist. Consistently, (1) the proliferative activity in the intermediate layer, (2) the rates of cell turnover and growth of chondroblasts and chondrocytes, (3) the rates of extracellular matrix production in the intermediate and chondral layers, as well as (4) the resorptive and (5) appositional activities in the zone of erosion were characterized by an in‐concert behavior. This behavior suggests a general synergistic control of the various cell dynamic and metabolic processes affecting the rate of normal condylar growth.
Fourth ventricular floor in human embryos: Scanning electron microscopic observations
Authors: Tanaka Osamu , Otani Hiroki , Fujimoto Katsukuni
Published: February 2005

The ultrastructural surface features of the normal fourth ventricular floor of seven human embryos ranging from Carnegie stage 14 to stage 19 (crown‐rump length: 7.6–16.2 mm) were examined by using scanning electron microscopy (SEM). Low‐power SEM views showed the median sulcus, sulcus limitans, and neuromeres, transient structures characteristic of the earlier embryonic period. High‐power SEM observation revealed supraependymal cells (SE cells) and supraependymal fibers (SE fibers) which exhibited a characterisitc localization, as well as generalized surface‐membrane modifications such as microvilli and cilia. SE cells could be classified into two major groups. The type 1 SE cells seem to possess neuronal functions, as deduced from morphological similarities to their counterparts in adults and the specialized distribution closely related to neuromeres. The type 2 SE cell morphologically resembled the phagocytic SE cell described in related literature. SE fibers ran a course either rostrocaudally in the median sulcus or mediolaterally on the neuromeres, most frequently near the interneuromeric cleft; they made contact with type 1 SE cells and ependymal surface modifications and then penetrated the ependymal layer.
Patterns of organelle distribution in mouse embryos during preimplantation development
Authors: Batten Bruce E. , Albertini David F. , Ducibella Tom
Published: February 2005

We have evaluated the distribution of mitochondria and acidic organelles using, respectively, the specific vital fluorescent dyes rhodamine 123 and acridine orange during preimplantation embryonic development in the mouse. Under conditions used to visualize organelles in living embryos, staining with either dye was found to have no effect on either the rate or extent of in vitro development of five‐ to eight‐cell embryos up to the blastocyst stage. Mitochondria were randomly distributed throughout the cytoplasm and located around nuclei in blastomeres of uncompacted embryos. During compaction, mitochondria initially reorganized to the blastomere cortex; however, these organelles were later confined to the perinuclear region in the trophectoderm (TE) of expanded blastocysts. Acidic organelles were randomly distributed in the cytoplasm of uncompacted embryos, but following compaction, they were concentrated in cortical and perinuclear locations. Moreover, in TE cells of expanded blastocysts, acidic organelles were found exclusively in a tight perinuclear pattern. Microtubules and microfilaments in TE cells were localized in fixed embryos stained with antitubulin antibodies and rhodamine phalloidin, respectively; these structures were found primarily in the cortical cytoplasm at areas of cell‐cell contact and secondarily in a perinuclear location. Thus mitochondria and acidic organelles undergo stage‐specific redistributions from a diffuse or cortical pattern at the eight‐cell stage to a tight perinuclear localization in the TE. We conclude that the polarized distributions of some organelles and cytoskeletal proteins during compaction may not be reliable permanent markers of the mature TE.
The Golgi apparatus in the acinar cells of the developing embryonic pancreas: II. Localization of lectin‐binding sites
Authors: Pavelka Margit , Ellinger Adolf
Published: February 2005

The reaction patterns of the Golgi apparatus following staining with the lectins concanavalin A (ConA), Ricinus communis I agglutinin (RCA I), and Helix pomatia lectin (HPA) were studied in the pancreas acinar cells of rat embryos in the course of cell differentiation from day 13 through day 20 of gestation. The binding reactions were localized by means of pre‐embedment incubation of 10‐μm‐thick cryosections of pancreas tissue, prefixed in a mixture of 4% formaldehyde/0.5% glutaraldehyde, using horseradish peroxidase for electron microscope visualization.

ConA, which preferentially binds to α‐D‐mannosyl residues, consistently stained the cisternae of the cis Golgi side. The majority of the stacks also showed ConA staining of medial cisternae. The reaction of the trans side was variable; in each stage of development, the cisternae of the trans Golgi side either were devoid of labeling or appeared intensely stained. The reactions obtained with RCA I, which recognizes terminal β‐D‐galactosyl residues, changed in the course of cell differentiation; in the protodifferentiated and early differentiated states, the system of “rigid lamellae,” located at the trans side of the Golgi stacks, was intensely labeled, but became unreactive after production of secretion granules had started, the reaction then being restricted to the stacked saccules. In regard to the Golgi stacks in each of the developmental stages, RCA I binding sites either were confined to the trans cisternae, or, in addition, were found distributed across elements of the medial and cis compartments. Frequently, the reaction intensities increased in the cis‐to‐trans direction. The Golgi patterns apparent after the staining with HPA, which interacts with α‐N‐acetyl‐D‐galactosaminyl residues, were variable at all stages of differentiation; the reactions either were restricted to the cis and/or medial cisternae, or expanded across the entire stack of saccules.

These results illustrate that the distribution across the Golgi stacks of binding sites for ConA, RCA I, and HPA is variable; none of the three lectins tested can be considered to be a probe for specifically labeling subsections of the Golgi stacks in developing pancreas acinar cells.
Transendothelial transport (transcytosis) of iron‐transferrin complex in the rat liver
Authors: Kishimoto Takumi , Tavassoli Mehdi
Published: February 2005

To determine the transport pathway of iron‐transferrin complex (Fe‐TF) into the hepatocyte, we labeled Fe‐TF with colloidal gold and perfused rat liver through the portal vein with this probe under different conditions. The tissue was then studied by transmission electron microscopy. At a cold temperature (∼ 4°C), the probe bound to the luminal surface of sinusoidal endothelium without internalization. The binding was limited to the endothelium and there was no binding to Kupffer cells or hepatocytes. The binding was inhibitable in the presence of excess soluble Fe‐TF, indicating the specificity of the bindings. At 37°C the probe was internalized via a system of coated pits and vesicles. Morphometric analyses of the temporal sequence of events suggested that the probe was transported, in part, across the endothelium via a system of tubules and vesicles and externalized on the abluminal side via a system of coated pits. The probe was then taken up by hepatocytes. Only minimal uptake was noted when gold‐labeled bovine serum albumin was used either at the low temperature or at 37°C. The findings suggest that the liver uptake of Fe‐TF complex by hepatocytes is a transendothelial phenomenon (transcytosis).
Synthesis and migration of 3H‐fucose‐labeled glycoproteins in the retinal pigment epithelium of albino rats, as visualized by radioautography
Authors: Haddad A. , Bennett G.
Published: February 2005

3H‐fucose was injected into the vitreous body of the eye(s) of 250‐gm rats, which were then killed by means of an intracardiac perfusion with glutaraldehyde after intervals of 10 min, 1 and 4 hr, and 1 and 7 days. The eyes were removed and further fixed, and pieces of retina were processed for light and electron microscope radioautography. Light microscope radioautography showed that the pigment epithelial cells actively incorporated 3H‐fucose label. The intensity of reaction peaked at 4 hr after injection of the label and then slowly declined. Quantitative electron microscope radioautography revealed that, at 10 min after 3H‐fucose injection, over 70% of the label was localized to the Golgi apparatus, indicating that fucose residues are added to newly synthesized glycoproteins principally at this site. With time the proportion of label associated with the Golgi apparatus decreased, but that assigned to the infolded basal plasma membrane, the apical microvilli, and various apical lysosomes increased. These results indicate that in retinal pigment epithelial cells newly synthesized glycoproteins continuously migrate from the Golgi apparatus to lysosomes and to various regions of the plasma membrane. In this case, the membrane glycoproteins may play specific roles in receptor functions of the basal plasma membrane or phagocytic activities at the apical surface. Very little label migrated to Bruch's membrane, indicating either a very slow turnover or a paucity of fucose‐containing glycoproteins at this site.
Heterogeneity of spindle units in the cat tenuissimus muscle
Authors: Kucera Jan , Walro Jon M.
Published: February 2005

Three tandem spindles and their nerve supplies, reconstructed by light microscopy of serial transverse sections of the cat tenuissimus muscle, were compared to single spindle units. Each tandem spindle consisted of one large unit containing a dynamic bag1, a static bag2, and several static chain fibers (b11b2c unit) linked by the bag2 fiber to a small unit containing only a bag2 and chain fibers (b2c unit). Most features of primary afferents, secondary afferents, and motor neurons were qualitatively and quantitatively similar in both single and tandem b1b2c units. However, b1b2c units of tandem spindles had a lower density of skeletofusimotor innervation than did single b1b2c spindles. The 2c spindle units differd greatly from single or tandem b1b2c units. The 2c spindle units had fewer intrafusal fibers and incoming axons than either the tandem or single b1b2c units. The motor innervation of b2c units was typified by nonselective γ axons that coinnervated both bag2 and chain fibers, in contrast to the regular occurrence of both selective and nonselective motor axons in b1b2c spindle units. The afferent located at the equator of 2c units differed in size, branching pattern, and intrafusal distribution of its ending from both the primary and secondary sensory axons of b1b2c units and, therefore, might represent a third category of spindle afferent. Thus, cat tenuissimus muscles contain three types of spindle units that differ in the number and organization of muscular and neural elements. These differences in structure and neural organization among tenuissimus spindle units may be a source for generation of different sensory signals in response to common mechanical or fusimotor stimuli.
Nuclear origins of brainstem reticulocortical systems in the rat
Authors: Newman Donald B. , Liu Rita P. C.
Published: February 2005

Stereotaxic injections of 5% Fast Blue or 1% horseradish peroxidase‐wheat germ agglutinin conjugate (HRP‐WGA) were made into various cytoarchitectonic or functional regions of the cerebral cortex of anesthetized adult albino or hooded rats. Sections through the brainstems of these animals were then scrutinized for the presence of retrogradely labeled neurons. The data generated by this study indicate that at least 33 distinct nuclei or subnuclei within the brainstem reticular formation of the rat project directly to the cerebral cortex. More than half of these ascending reticulocortical systems are probably aminergic. The strongest reticulocortical projections emanate from presumed aminergic reticular‐cell groups located at isthmic levels: specifically, the rostral serotonin‐containing cell groups, as well as the noradrenergic locus coeruleus. However, relatively strong direct reticulocortical projections also originate from lower medullary cell groups which are probably catecholaminergic. Moderately strong reticulocortical projections emanate from cholinergic cell groups located at isthmic levels (the pars compacta of the pedunculopontine nucleus and the X area of Sakai). The most surprising finding in this study was that the classic isodendritic, nonaminergic central core of the brainstem gives rise to direct reticulocortical projections. The ventromedial areas of the medullary brainstem reticular formation give rise to the strongest nonaminergic ascending reticular projections, but all levels of the classic isodendritic reticular core give rise to direct reticulocortical projections. As a whole, cortically projecting reticular neurons are mostly small (10–25 μm in greatest diameter) or medium sized (26–35 μm in greatest diameter) neurons.

Previous studies have shown that many of the cortically projecting reticular nuclei also project to the spinal cord, and, within these nuclei, reticulocortical neurons often strongly resemble their reticulospinal counterparts with respect to details of neuronal morphology. This in turn suggests that some reticulocortical neurons may also project to spinal levels.
The osteopetrotic rabbit: Skeletal cytology and ultrastructure
Authors: Marks Sandy C. , MacKay Carole A. , Seifert Mark F.
Published: February 2005

The lethal, autosomal recessive osteopetrotic mutation in the rabbit, osteosclerosis (os/os), has recently been made available for experimental investigation. We have examined the cytology and ultrastructure of skeletal cells in mutants and report abnormalities in osteoblasts, osteocytes, and osteoclasts. Mutant osteoclasts lack a well‐defined ruffled border and show few morphological signs of bone resorption. Osteoblasts in mutants form bone in neonatal life but show signs of degeneration by 2 weeks after birth. Mutant osteoblasts and osteocytes contain large, electron‐dense cytoplasmic inclusions. External surfaces of mutant long bones show no evidence of bone resorption by scanning electron microscopy, and fibrosis of intertrabecular spaces is a prominent feature in mutants. These data, considered with recent evidence that the functions of osteoblasts and osteoclasts are interrelated, suggest that reduced bone resorption, a characteristic feature of osteopetrosis, may be related to osteoblast incompetence in this mutation.
Changes in leydig cell activity during the annual testicular cycle of the bat Myotis lucifugus lucifugus: Histology and lipid histochemistry
Authors: Gustafson A. W.
Published: February 2005

Changes in Leydig cell histology and testicular sudanophilic lipids were examined in relation to spermatogenic activity in the bat Myotis lucifugus lucifugus (Chiroptera: Vespertilionidae) throughout the annual cycle in the northeastern United States. These changes were correlated with annual variations in plasma testosterone concentrations which have recently been described for this species. Gametogenic activity occurred during the months of May‐August when bats were metabolically most active. During hibernation (October‐April), when sperm are stored in the epididymides, and accessory glands are hypertrophic, the seminiferous tubules were at rest, and the germinal epithelium was reduced to reserve spermatogonia and Sertoli cells. Based on their structure and cyclic pattern of sudanophilic lipids, Leydig cells exhibited a pattern of activity that closely paralleled that of the seminiferous epithelium. On renewal of spermatogenesis in spring, Leydig cells became hypertrophied and accumulated lipid inclusions. These inclusions, seen as vacuoles in plastic sections and sudanophilic droplets in frozen sections, reched maximal accumulations in late June. In late July and during August, when peak testosterone levels occur in blood, lipid droplets were dramatically depleted, and Leydig cells were weakly sudanophilic. In September, when testosterone titers return to low baseline levels, Leydig cells had regressed but exhibited a marked increase in sudanophilic inclusions which appeared to be mostly lipofuscins. During the ensuing mating and hibernation periods, Leydig cells were involuted and filled with lipofuscins. During the periarousal period, however, Leydig cells became weakly Sudan‐positive while many large, intensely sudanophilic cells were scattered throughout the interstitium. In electron micrographs these cells were identified as macrophages. They appear to play an important role in the annual testicular cycle by phagocytizing the residues of Leydig cell involution in preparation for a new steroidogenic cycle. Seasonal changes in lipid inclusions were also observed in the seminiferous tubules. In addition, the relationship of the Leydig cell cycle to androgen action and the accessory organs in this bat is discussed.
Plasma membrane structure of bat spermatozoa: Observations on epididymal and uterine spermatozoa in Myotis lucifugus
Authors: Hoffman L. H. , Wimsatt W. A. , Olson G. E.
Published: February 2005

Plasma membrane structure of bat spermatozoa was examined utilizing electron microscopy of thin sections and freeze‐fracture replicas. Notable membrane features observed in replicas from cauda epididymal spermatozoa included specialized particle aggregates at the junction between the acrosomal and postacrosomal region of the head (a membrane structure not previously described in mammalian spermatozoa) and another row of rod‐like particles just anterior to the posterior ring. Both of these specializations in fractured plasma membranes correspond with regions where the membrane is closely apposed to underlying structures when viewed in thin sections. The postacrosomal sheath appears to be composed of an array of longitudinally oriented filamentous components. Characteristic ordering of intramembranous particles was also noted in replicas from the midpiece region and the annulus. Major changes in plasma membrane structure were not seen in spermatozoa stored in the female reproductive tract; however, the appearance of linear particle aggregations in the principal piece membrane was noted. No evidence was obtained to suggest that an acrosome reaction had occurred in spermatozoa stored in females.
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

Rhinopoma 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

The 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

The 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

The 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

Studies 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

Morphological 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

The 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

The 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

Corpora 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

The 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

Two 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

Five 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.