bluuebunny/crossref_metadata_2025 huggingface dataset:
Variation of mouse intestinal epithelial whole population cell kinetics during the estrous cycle
Authors: Cheng Hazel , Bjerknes Matthew
Published: February 2005

There are contradictory reports on the effect of the estrous cycle on cell proliferation in the intestinal epithelium. We reexamined estrous‐cycle‐related changes in the epithelium by using flow cytometry and Coulter particle counting. We found significant estrous‐cycle‐related variations in both the distribution of epithelial cells through the cell cycle as well as the number of epithelial cells per unit area in mouse jejunal and colonic epithelium.
Presence of glial cells in the rat pineal gland: A light and electron microscopic immunohistochemical study
Authors: Calvo J. , Boya J. , Borregon A. , Garcia‐Mauriño J. E.
Published: February 2005

Immunoperoxidase methods for the demonstration of three glial antigens, vimentin, glial fibrillary acidic protein, and S‐100 protein, were applied to routine‐fixed paraffin sections of rat pineal gland. A pre‐embedding electron microscope immunoperoxidase method was also used to study the ultrastructural localization of S‐100 protein in pineal cells. Light and electron microscopic results showed the presence of these antigenic glial markers in the second pineal cell type. The term glial cell is proposed for the second of parenchymatous cell in rat pineal gland.
Early morphogenesis of the canine lens, hyaloid system, and vitreous body
Authors: Boevé M. H. , van der Linde‐Sipman J. S. , Stades F. C.
Published: February 2005

This study deals with the early morphogenesis, from day 25 to day 35 post coitum (D25–D35), of the canine lens, lens capsule intraocular vascular system, and vitreous body. The breeding method used provides a higher accuracy as to the gestational age of the obtained fetuses than employed previously.

The development of the lens, the intraocular vascular system, and the vitreous body of the dog's eye is analogous to that in other mammal species. The findings of this study, combined with data obtained from the literature, suggest that the period during which ocular development takes place is earlier in larger mammalian species than in the smaller ones.

Previous descriptions of ocular development in other mammalian species, and one in the dog, reported that the development of the lens capsule starts posteriorly and proceeds towards the anterior part of the lens vesicle. In the present study, the periodic acid—Schiff positive anlage of the capsule was observed to fully surround the lens vesicle at D25, a development that is different and earlier than described previously in the dog and different from that described in other mammals. Moreover, a clear thickening of the capsule was not observed until capillaries of the tunica vasculosa lentis had reached its proximity.
Immunocytochemical localization of a kallikrein‐like serin protease (Esterase A) in rat salivary glands
Authors: Simson J. A. V. , Condon J. , Fenters R. , Chao L. , Chao J.
Published: February 2005

Light and electron microscopic (EM) immunocytochemical methods have been used to localize arginine esterase A, a kinin‐generating enzyme immunologically similar to tissue kallikrein, in rat salivary glands. Both polyclonal and monoclonal antibodies to arginine esterase A were used in these studies. By means of a polyclonal antiserum, esterase A was found in granular tubules of submandibular glands and in striated ducts of all three major salivary glands, in a distribution similar to that of tissue kallikrein. With recently developed specific monoclonal antibodies to esterease A, this enzyme was localized in the granules of some (but not all) granular convoluted tubule cells (GCT) and along the basal membranes (but not in apical granules) of striated ducts. By an EM immunoperoxidase method, esterase A was localized subcellularly in granules of some GCT cells and along the basal cell membranes of the tubule and duct system. Thus, this enzyme is found in some sites (GCT granules) shared with tissue kallikrein, but in some unique sites, i.e., basal membranes of striated ducts. The polyclonal antibody used in the present study cross‐reacted with tissue kallikrein, but when absorbed with kallikrein, it gave the staining pattern characteristic of monoclonal antibody to esterase A.
Lung lamellar body amphiphilic topography: A morphological evaluation using the continuum theory of liquid crystals: II. Disclinations, edge dislocations, and irregular defects
Authors: Zasadzinski J. A. N. , Stratton C. J. , Rudolphi R.
Published: February 2005

The bilayers in normal mammalian and human lung multilamellar bodies (LMB) are parallel, equally spaced, and continuous—a configuration that minimizes the large elastic strain energy associated with changing the equilibrium bilayer separation and the hydrophobic–hydrophilic repulsion energy between the hydrocarbon tails of phospholipid and the aqueous phase. This ideal behavior is disrupted at a limited population of large Burgers vector edge dislocations dissociated into ± 1/2 disclination pairs. The configuration and interaction of the defects are explained by the continuum theory of liquid crystals and shown to be identical to defects observed in in vitro surfactant liposomes and bilayers. We report the first observations with molecular resolution of the core structure of a liquid crystal dislocation. Defect cores are shown to be located between both headgroups and tailgroups in human LMB, suggesting that both types of core are similar in energy. This may be the result of partitioning of proteins or other nonlipid impurities in the LMB to the defect cores, which might also change the stability of the dislocations to favor their preservation. The edge dislocation defects interact in ways that minimize their overall strain energy. A population of edge dislocations may play an important role in the transport or localization of certain molecules through the lamellar body. Certain defects were observed in lung multilamellar bodies that have not been observed in in vitro systems; these are probably due to the complex, multicomponent nature of the LMB surfactant and the dynamic, in vivo environment of the LMB.
Tracheobronchial epithelium of the sheep: III. Carbohydrate histochemical and cytochemical characterization of secretory epithelial cells
Authors: Mariassy Andrew T. , St. George Judith A. , Nishio Susan J. , Plopper Charles G.
Published: February 2005

We examined histochemically (light microscopy‐LM) and cytochemically (electron microscopy‐EM) the secretory epithelial cells in the tracheobronchial mucosa of sheep. Six morphologically distinct, granule‐containing cells have been described, on the basis of their morphology and airway distribution: four mucous (M1–M4), serous (SC), and Clara (CC). Stereological and morphometric data indicated that M3, M4, SC, and CC were distinctly different from each other and from M1 and M2 cells. Mucous cells M1 and M2 differed in granule morphology. Samples of tracheas, sixth‐generation bronchi, distal bronchi, and terminal bronchioles of 18 adult sheep were examined. At the LM level, methacrylate sections were reacted with an alcian blue (pH 2.5), periodic acid Schiff (PAS) sequence to differentiate neutral from acidic glycoconjugates (GC), and a high‐iron diamine (HID), alcian blue sequence to differentiate sulfated from nonsulfated (sialated) GC. At the EM level the periodic acid–thiocarbohydrazide localized hexose‐rich, neutral GC. Dialyzed iron (DI) and high‐iron diamine localized carboxylated and sulfated GC, respectively. Granules of all but Clara cells were PAS‐positive. All mucous cells contained acidic groups, but only M1 and M4 cells had LM‐detectable sulfated GC. At the ultrastructural level, minimal but discernible HID and LID reaction product was observed on granule profiles of M2, M3, and SC, indicating acidic and sulfated GC not detected at the LM level. Histochemically, the sheep tracheobronchial epithelium was more similar to that of humans than some other examined mammalian species.
Contribution of the golgi apparatus components to the formation of the acrosomic system and chromatoid body in rat spermatids
Authors: Thorne‐Tjomsland G. , Clermont Y. , Hermo L.
Published: February 2005

The cytochemical distribution of two different acid phosphatases, nicotinamide adenine dinucleotide phosphatase (NADPase) and cytidine monophos phatase (CMPase), was analyzed within the Golgi apparatus, acrosomic system, and chromatoid body of early spermatids. Within the saccules composing the Golgi cortex, the phosphatases were localized in specific and nonoverlapping compartments: the cis‐tubular network, or cis‐element, and the first underlying saccule were unreactive for both enzymes, the following four to five saccules were reactive for NADPase, and the last three saccules were reactive for CMPase. Vesicles of various sizes and short membranous tubules, present near the edges of saccules and in the medulla of the Golgi apparatus, were NADPase‐ and/or CMPase‐positive. The acrosomic system showed a weak but significant NADPase reactivity and a strong CMPase reactivity. The vesicles associated with the chromatoid body were reactive for NADPase and/or CMPase. The combined observations indicate that the two cytochemically distinct compartments of the Golgi cortex, the NADPase‐ and CMPase‐positive saccules, independently contribute to the formation of the acrosomic system and the vesicular component of the chromatoid body.
Localization of actin in human, bull, rabbit, and hamster sperm by immunoelectron microscopy
Authors: Flaherty Sean P. , Winfrey Virginia P. , Olson Gary E.
Published: February 2005

Mammalian spermatozoa have previously been shown to contain actin, but its subcellular localization and function have not been elucidated. In this study, actin has been localized at the ultrastructural level in human, bull, rabbit, and golden hamster spermatozoa by a monoclonal antiactin antibody and a preembedding immunogold labeling technique. Specific labeling was localized 1) around the connecting piece in the neck region of sperm from all four species, although a species‐specific pattern was evident; 2) on the external surface of the fibrous sheath of human sperm; 3) in the perinuclear space underlying the postacrosomal sheath of bull and rabbit sperm; and 4) between the plasma membrane and outer acrosomal membrane along the concave margin of the hamster sperm head. SDS‐PAGE and Western blots immunostained with the monoclonal antibody confirmed the presence of actin in SDS extracts of Percoll‐purified sperm from each species.
Observations of vascularization in the spinal cord of mouse embryos, With special reference to development of boundary membranes and perivascular spaces
Authors: Nakao Taisuke , Ishizawa Akimitsu , Ogawa Reiko
Published: February 2005

The early stages of vascularizations of the spinal cord of the mouse were studied by graphic reconstruction techniques and electron microscopy. Vascular sprouts arise from the perineural vascular plexus (PNVP) to invade the cord of 10‐day embryos. These enter the cord most frequently via the lateral surface between the dorsal root and the ventral root; less frequently, they enter via the ventral and/or dorsal surfaces and anastomose with sprouts that have entered via the lateral surface.

During the development of intramedullary blood vessels there are essential changes both in the basal laminae covering the neural parenchyma of the cord and in the relationship between the neural tissue and vascular walls. The basal laminae of the developing spinal cord were classified into three categories. The first is the perineural, external, or primary neural, basal lamina (PNBL), which is the earliest of the three in formation and covers the entire external surface of the cord. The second one is the internal, or secondary neural, basal lamina (INBL), which invests the internal surface of the neural tissue facing the walls of invading blood vessels. The third type is the perivascular basal lamina (PVBL), which surrounds the vascular wall.

Blood vessels enter the spinal cord by penetrating the PNBL. Since the PVBL and INBL are absent or incomplete in early stages of vascularization, the neural tissue is in direct contact with intramedullary blood vessels. However, following their development, boundary membranes are formed, separating the neural tissue from neighboring vessels, a situation characteristic of capillaries in the mature CNS. Perivascular spaces are seen along the course of developing vessels and secondarily become continuous with the extramedullary connective tissue space. They are neither artifact nor intramedullary extensions of extramedullary connective tissue space along invading sprouts. The boundary membranes are formed by connection of membrane plaques or by fusion of the INBL and PVBL.
Development of arteries in embryonic chick bone marrow with special reference to the appearance of periarterial granulopoietic sheaths
Authors: Michael Sorrell J.
Published: February 2005

Arterial development was studied in embryonic chick bone marrow starting on day 11 of incubation and continuing until day 18. Arteries first appear on day 11 as vessels with two components to their wall structure, namely a thin, complete endothelium and a nearly complete pericyte layer. With advancing age, three distinct layers—an endothelium, a complete muscularis, and adventitia—appear. Long, narrow endothelial cells from cellular junctions at their basal surfaces. Smooth muscle cells remain relatively undifferentiated and do not consist of more than three layers even in the largest arteries. The adventitia consists of a hypocellular zone containing fibroblasts and a collagenous extracellular matrix. Unmyelinated nerves are located at the peripheral margin of the adventitia. All of the larger arteries are surrounded by a sheath of heterophilic granulopoietic cells. These cells do not intrude into the adventitia, but basophilic or mast cells often do intrude. The stromal cells of the periarterial granulopoietic sheaths remain as either fibroblastic cells or as multilocular preadipocytes. They, unlike those stromal cells beyond the sheath, never become unilocular adipocytes. By day 18, granulopiesis is restricted to the periarterial sheaths and to the endosteal regions of the marrow. These studies indicate that fibroblastic stromal cells and preadipocytes, but not fully developed adipocytes, support granulopoiesis in the chick marrow. The stromal cells in the periarterial sheaths either represent a subpopulation of cells that do not develop into adipocytes or represent cells whose development into adipocytes is locally inhibited.
Electron microscopic cytochemical localization of Ca‐ATPase in the rod outer segments of the toadBufo marinus
Authors: Davis Walter L. , Hagler H. K. , Farmer Gene R. , Martin James H. , Bridges George
Published: February 2005

Transmission electron microscopy and ultracytochemistry were employed in an attempt to localize the enzyme calcium adenosine triphosphatase (Ca‐ATPase) in the rod outer segments (ROS) of the toad retina. Utilizing a one‐step incubation procedure, Ca‐ATPase was identified as an electron‐dense precipitate in the intradiskal spaces of the rod disks (vesicles) of the ROS. Analytical microscopy identified the reaction product as lead phosphate. The formation of the reaction product was dependent on the presence of ATP (the substrate) and calcium ions. However, calcium ions could be substituted for by magnesium ions. In addition, the reaction was vanadate sensitive. The latter is known to inhibit Ca‐ATPase activity. Such data appear to indicate the presence of a Ca‐Mg‐ATPase in association with the rod disks. Since cyclic guanosine monophosphate (cyclic GMP), rather than calcium ions, is currently believed to be the primary intracellular messenger associated with phototransduction, the presence of an ROS Ca‐ATPase may indicate other functions for this cation in the physiology and biochemistry of the visual process. Ca‐ATPase might play a role in directional calcium fluxes between intracellular compartments.
Involvement of cathepsins B and H in lysosomal degradation of horseradish peroxidase endocytosed by the proximal tubule cells of the rat kidney: II. Immunocytochemical studies using protein A‐gold technique applied to conventional and serial sections
Authors: Yokota Sadaki , Kato Keitaro
Published: February 2005

Immunoelectron microscopic localizations of cathepsins B and H and injected horseradish peroxidase (HRP) in the lysosomal system of rat kidney proximal tubules were investigated by a protein A‐gold technique. Kidneys were fixed by perfusion at fixed intervals after intravenous injection of HRP. At 5 to 15 minutes after the injection, the endocytic apparatus—including the apical vesicles, tubules, and vacuoles (endosomes)—were stained for HRP, but they were negative for cathepsins. Within 15 to 30 minutes after the HRP injection, HRP‐containing endosomes were fusing with preexisting lysosomes. In the S1 segment, they accumulated in the apical cytoplasm and formed giant phagosomes, which increased markedly in number and size after 1 hour. These phagosomes were composed of a peripheral clear matrix and electron‐dense inclusions. The clear matrix was stained heavily for cathepsins and HRP, whereas the electron‐dense inclusions were consistently negative for cathepsins and HRP. The same results also were obtained after the double‐labeling and serial sectioning techniques. The dense inclusions were fragmented gradually as the phagosomes decreased in size. After 3 hours, the size and number of phagosomes returned to their normal state (before the HRP injection). These results indicate that the endocytic apparatus of the proximal tubule cells does not contain cathepsins. Phagosomes are formed by the fusion of endosomes containing the internalized protein with the preexisting lysosomes. The degradation of HRP in giant phagosomes occurred rapidly. The coexistence of cathepsins B and H with the endocytosed HRP suggests that these cystein proteinases are involved in the degradation of protein in heterophagosomes of the proximal tubule cells.
Existence of vocal folds in the larynx of odontoceti (toothed whales)
Authors: Reidenberg Joy S. , Laitman Jeffrey T.
Published: February 2005

Odontocetes (toothed whales) vocalize for communication and echolocation. The mechanisms of sound production, however, remain unclear. Their larynx has long been thought to lack vocal folds and, thus, was considered incapable of generating sounds. This study investigates internal anatomy of the odontocete larynx to: 1) describe the morphology of any fold found, 2) determine any structural homologies between these folds and the vocal folds of terrestrial mammals, and 3) assess their possible function in sound production. Larynges of 24 odontocetes representin ten genera (Delphinus, Stenella, Lagenorhynchus, Tursiops, Grampus, Delphinapterus, Globicephala, Kogia, Mesoplodon, and Phocoena) were studied post mortem. Nine specimens were cut midsagittally, and the remainder were dorsally opened to reveal internal anatomy. Results show that, contrary to established belief, vocal folds are consistently present. They are not isolated bands or “cords” but appear continuous with the internal laryngeal membrane. The attachments of these folds are the same as in terrestrial mammals, thus indicating homology with true mammalian vocal folds. These folds extend from the midline of the thyroid cartilage to the base of the arytenoid cartilages, sometimes to a discrete process. The vocal folds are elongated and oriented in a vertical plane, parallel to airflow direction. Vocal fold morphology varies, appearing as true bifurcated structures, a trifurcated fold, or a single midline fold. Laryngeal ventricles and vestibular folds are also consistently found lateral to the vocal folds. The vocal folds may divide the airstream within the into three separate air currents. Fold vibrations may produce initial laryngeal sounds used in echolocation or communication.
The mouse pericardium: It allows passage of particulate matter from the pleural to the pericardial cavity
Authors: Fukuo Yoshifumi , Nakatani Toshio , Shinohara Harumichi , Matsuda Takeshi
Published: February 2005

Frog erythrocytes injected into the pleural cavity of mice reached the pericardial cavity. Pericardial pores that connect the two cavities were the routes of the migration. As soon as 5 minutes after injection, frog erythrocytes were surrounded and phagocytosed by attached macrophages in milky spots facing the pericardial cavity. The pericardial pores may function in an allied self‐defense mechanism between the pleural and pericardial cavities in this species.
Nerve pathways between the pterygopalatine ganglion and eye in cats
Authors: Lin Ton , Grimes Patricia A. , Stone Richard A.
Published: February 2005

By dissection of thiocholine‐stained orbital preparations, it has been determined that three different nerve pathways link the pterygopalatine ganglion and the eye in cats. (1) Nerves from the proximal half of the ganglion join a plexus of nerves and ganglion cells in the rete mirabile of the maxillary artery. Branches of the internal carotid nerve also supply this plexus. Fine nerves from the plexus travel to the optic nerve and then to the eye, accompanying both the nasociliary nerve that passes through the rete and the ciliary arteries that arise from the rete. (2) One or more nerves from the nerve of the pterygoid canal and from a prominent accessory ganglion near the orbital apex course to the inferior optic nerve surface at the optic foramen; these then run distally along the optic nerve to fuse with ciliary nerves or to accompany ciliary arteries entering the eye. (3) Other nerves from the pterygopalatine ganglion travel medially around the extraocular muscle cone to join the ethmoidal and infratrochlear branches of the nasociliary nerve; some nerves from the ganglion then take a retrograde course to the optic nerve, where they join ciliary nerves or arteries to the eye. All three pathways may transmit sympathetic, parasympathetic and somatic sensory nerve fibers.
An immunohistochemical study of the ontogeny of the horizontal cell in the rat retina using an antiserum against spot 35 protein, a Novel purkinje cell‐specific protein, as a marker
Authors: Kondo Hisatake , Yamamoto Miyuki , Yamakuni Tohru , Takahashi Yasuo
Published: February 2005

A sequence of morphological changes during the differentiation of retinal horizontal cells was studied by means of immunohistochemistry for spot 35 protein, a novel Purkinje cell‐specific protein, in the rat retina. Spot 35‐immunoreactive horizontal cell anlagen were first identified at embryonic day 18 (E18) in the outer zone of the neuroblastic cell layer as fusiform cells with slender inner and outer processes. As the development proceeded, the immunoreactive cells increased in number and intensity of the immunostaining, and the outer processes of the immunoreactive cells were often bifurcated close to their origin or at their periphery. At postnatal days 3 and 5 (P3 and P5), a regional difference in morphology of the immunoreactive horizontal cell anlagen was recognized: The immunoreactive cells near the ora serrata still assumed a bipolar shape, and those in the central portion of the retina had multiple processes. At P7 and P10, the immunoreactive cells in the periphery of the retina extended most of their outer processes in the plane of the retina, forming a network together with processes of adjacent immunoreactive horizontal cells. Their internally extending processes during these postnatal stages tended to be present in small numbers and to be short. At P14 all the immunoreactive horizontal cells extended their processes horizontally to form a tight bundle all the way along the outer plexiform layer. These findings indicate that spot 35 protein is a specific marker for the horizontal cells of the rat retina in the developmental process from their bipolar stage at E18 until reaching their mature configuration at P14.
Scanning electron microscope study of the spatial organization of the air and blood conducting components of the avian lung (Gallus Gallus variant domesticus)
Authors: Maina J. N.
Published: February 2005

The lungs of the domestic fowl were prepared for scanning electron microscopy after vascular and airway latex rubber casting to demonstrate the spatial organization of the various structural components that are involved in the gas exchange that takes place in the parabronchial tissue mantle. The bulk of the intrapulmonary air flows through the parabronchial lumen and then centrifugally diffuses into the exchange tissue through the atria, the infundibula, and the air capillaries. The blood flows centripetally from the interparabronchial arteries, then into the intraparabronchial arterioles, and finally into the blood capillaries, which together with the air capillaries constitute the functional terminal gas exchange units. The relationship between the air flow in the parabronchial lumen and the incoming blood (into the exchange tissue) has been shown to be crosscurrent, where the directions of the flow of these two gas exchange media are essentially perpondicularly disposed to each other; whereas the relationship between the blood capillaries and the air capillaries is countercurrent, the blood flowing towards the parabronchial lumen and the air in the opposite direction, i.e., towards its periphery. Both these spatial structural relationships between the air and blood are significant factors that contribute to the remarkable efficiency of the avian lung in gas exchange. The crosscurrent system enhances the duration of interaction between the parabronchial air and the blood, the oxygen being extracted from a parabronchus along its whole length, whereas the overall contribution of the countercurrent relationship, which is superimposed on the crosscurrent system, is not expected to be very high, mainly because of the tortuosity and profuse interlacing of the blood and air capillaries over a relatively short distance, that of approximately the thickness of the parabronchial tissue mantle.
Morphometric and statistical analyses describing the In utero growth of human epidermis
Authors: Foster Carolyn A. , Bertram John F. , Holbrook Karen A.
Published: February 2005

Epidermal development of human embryonic and fetal skin from the lower limb was studied using morphometric and statistical methods. Epidermal grooth, as defined by an increase in epidermal thickness and the number of cell layers, occurred in three distinct stages during the first and second trimesters. The first growth spurt occurred between 5 and 13 weeks estimated gestational age (EGA) and was followed by a plateau phase with little change in epidermal thickness from 14 to 21 weeks, after which the epidermis began to increase in height again. The periderm reached its maximal height by approximately 13 weeks EGA, and by 25 weeks was shed into the amniotic fluid. Thus, within a five‐month period (5 to 25 weeks EGA) the epidermis changed from a single cell layer < 10 μ thick to a 10 to 12‐cell layer, keratinized epithelium >60 μ thick. In contrast, epidermis from adult lower limb consisted of about 25 cell layers and was almost 75 μ in thickness. The age‐related differences in epidermal thickness probably reflect changes in cell size and shape more than changes in the directional movement (apically vs. laterally) of proliferating keratinocytes, because the addition of cell layers throughout development was relatively constant. During the plateau phase, when there is a rapid increase in fetal growth rate, the suprabasal keratinocytes become more flattened, thereby allowing for the addition of new cell layers while maintaining a relatively constant epidermal thickness. The loss of glycogen reserves, along with other intrinsic cellular changes, probably contributes to the flattening effect. However, the internal expansion of growing tissues also may exert a mechanical pressure that could stretch the skin passively and influence epidermal structure.
Effects of long‐term testosterone exposure on ovarian function and morphology in the rhesus monkey
Authors: Faiman C. , Reyes F. I. , Dent D. W. , Fuller G. B. , Hobson W. C. , Thliveris J. A.
Published: February 2005

This study was aimed at developing a model in the rhesus monkey for the human gynecologic disorder termed the polycystic ovary syndrome (PCOS). The effects of chronic constant androgen exposure upon quantitative ovarian morphology and ovulatory function were examined. Twenty‐five normally cycling females, aged 4–12 yr and weighing 3.3–8.2 kg, were enrolled in the study in random fashion. Seventeen animals were implanted subcutaneously (s.c.) with 10 or 25 mg testosterone‐filled silastic tubing so as to maintain steady serum levels of testosterone averaging 80 ng/dl (low‐dose group, n=8) and 115 ng/dl (high‐dose group, n = 9) for 13–16 months. Eight animals served as controls (sham implants); in these, mean serum testosterone levels averaged 24 ng/dl. No effect of androgen treatment was observed on ovulatory function as gauged by periodic luteal phase progesterone determinations and the presence of a fresh corpus luteum at laparoscopy. Menstrual cycle frequency (number of cycles over number of months of observation) was, however, slightly but significantly (P 7lt; 0.05) reduced in the high‐dose (88.9%) vs. the control (96.7%) and low‐dose (95.0%) groups. Quantitative morphology, performed by light microscopy on a single ovary obtained from 16 of the 25 animals and read in a blinded fashion, revealed no differences in ovarian weight, capsular width and numbers, size, or proportion of healthy and atretic follicles among the three groups. Although constant long‐term testosterone exposure failed to result in a picture resembling the human PCOS counterpart, factors such as higher levels, a longer duration of exposure, a different type of androgen used, or a critical peripubertal period of exposure will have to be considered in future experiments.
Effects of diltiazem on isoproterenol‐ or Ca‐induced ventricular myocardial cell injuries in isolated perfused rabbit heart: An electron microscopic study
Authors: Kim Ho‐Dirk , Rah Bong‐Jin
Published: February 2005

The ultrastructural changes of isoproterenol‐ and those of Ca‐induced ventricular cell injuries were compared in rabbits and the effect of diltiazem on these injuries was studied by electrom microscopy.

In comparison with the controls, the isoproterenol‐treated (Group A), the Ca‐treated (Group B), and the diltiazem‐posttreated (Groups E and F) showed severe myocardial cell damage, such as sarcolemmal disruption, mitochondrial swelling, intramitochondrial electron‐dense granules, membranous structures along mitochondrial cristae, thickening or close packing of the Z‐lines, separation of cell junctions, frayed myofibrils, clumping of chromatin, and intracellular fluid accumulation. These ultrastructural changes were more pronounced in the Ca‐treated (Groups B and F) than in the isoproterenol‐treated (Groups A and E) animals. In contrast, the diltiazem‐pretreated groups (Groups C and D) showed relatively intact myocardial ultrastructure. However, intramitochondrial electron‐dense granules could be frequently found, and particularly the diltiazem‐pretreated and Ca‐treated group (Group D) showed intracellular fluid accumulation.

The results of this study could suggest the following: (1) isoproterenol‐induced myocardial cell damage is similar to Ca overload, (2) pretreatment with diltiazem could reduce the deleterious effects of isoproterenol‐induced myocardial cell damage, but it could not prevent the effects of Ca overload completely, and (3) posttreatment with diltiazem could not provide any beneficial effect either on the isoproterenol‐induced or on the Ca‐overloaded mycoardial cell damage, and (4) the beneficial effects of diltiazem are probably derived from the enhanced buffering function of mitochondria to cytosolic Ca or from selective inhibition of transsarcolemmal Ca influx.
Cell death in the ventral region of the neural retina during the early development of the chick embryo eye
Authors: Martín‐Partido Gervasio , Rodríguez‐Gallaro Lucía , Alvarez Ignacio S. , Navascués Julio
Published: February 2005

The present study deals with morphologic and quantitative changes that take place in the area of cell death in the ventral part of the presumptive retinal wall of the chick embryo. These changes were followed from the optic vesicle stage until the first optic fiber fascicles leave the neural retina. Our results show that both the volume occupied by the area of cell death and the density of its pyknotic fragments undergo considerable variation during the period between Hamburger and Hamilton's (1951) stages 12 to 20. In the optic vesicle stages, cell death in the ventral wall of the vesicle was observed in 50 to 75% of the embryos studied. During stages 14 and 15, this zone was seen in more than 90%. By the time invagination of the optic cup was complete, the ventral retinal zone of cell death had disappeared entirely in a large proportion of embryos; in all other, it shrank significantly both in volume and density of pyknotic fragments. In stage 19, when the first optic fiber fascicles begin to emerge from the retina, a dramatic increase occurs in the number of pyknotic fragments in the posterior pole of the retina. The appearance of dying cells, in a region shortly to be traversed by developing ganglion cell axons, supports the hypothesis that cell death processes are apparently somehow related to the creation of a suitable environment for the emergence of fibers toward the optic stalk. Densities of mitotic and interphasic cells as well as the mitotic index were determined in both the retinal zone of cell death and in areas devoid of dead cells. In all developmental stages analyzed, the mitotic index was notably lower in the former than in non‐necrotic zones, suggesting that cell proliferation is partially inhibited in retinal areas of cell death.
Familial male pseudohermaphroditism and testicular descent in the racoon dog (Nyctereutes)
Authors: van Vlissingen J. M. Fentener , Blankenstein M. A. , Thijssen J. H. H. , Colenbrander B. , Verbruggen A. J. E. P. , Wensing C. J. G.
Published: February 2005

Sexual differentiation was investigated in familial male pseudohermaphroditism in Nyctereutes procyonoides (Canidae). In intersex males, development of external genital organs and prostate glandular tissue was severely disturbed; Wolffian (mesonephric) duct derivatives developed prepubertally but were absent in some adults. Müllerian (paramesonephric) duct regression was complete. Testicular descent was undisturbed. Male/female sex differences in plasma testosterone, 5α‐dihydrotestosterone, and luteinizing hormone concentrations were present. Intersex plasma hormone concentrations were within the normal male range. The concentration of androgen receptors in pubic skin was similar in male, female, and intersex animals and no significant differences in affinity for the ligand were detected.

It was concluded that in intersex animals androgen‐dependent virilisation was deficient despite the presence of androgens and androgen receptors and that this condition had not affected gubernaculum development and testicular descent.
Stereological study on the mode of optic cup expansion and the accumulation of mitoses in the early stages of chick embryo development
Authors: Calvente Ruth , Carmona Ramón , Abadí‐Molina Francisco , Abadía‐Fenoll Francisco
Published: February 2005

The present study was designed to contribute to our understanding of the factors that take part in the development transformation of the optic vesicle into the optic cup. The expansion and formation of this structure are dependent upon factors such as cellular proliferation, the space or zone occupied by the growing optic cup, and environmental influences. Our investigation in the chick embryo analyzes the relationship between retinal thickness and ventricular mitotic density. This relationship is shown in the study as PEI (proliferation‐expansion index). That index varies in the superior, medial and inferior regions of the retina when the zones of the same stage are compared, as well as in the comparisons of values between the 13–14 stage and the 17–18 stage. These differences indicate a different behavior of the cells constituting the retinal regions. Also discussed is the influence of the retinal fissure on the morphological changes observed during optic cup development.
Suppression of erythroid cell differentiation in mouse embryos exposed to retinoic acid in utero
Authors: Yasuda Yoshiko , Konishi Hiroyoshi , Matsuo Takuya , Tanimura Takashi
Published: February 2005

Differentiation of circulating erythrocytes was inhibited by all‐trans‐retinoic acid in 8‐ and 9‐day‐old mouse embryos exposed in utero on day 8 of gestation. Histochemical, light, and electron microscopic examinations revealed that all‐trans‐retinoic acid first decreased the numbers of polychromatic erythroblasts and then increased them. Simultaneously, immature erythroblasts proliferated, and differentiation of mature primitive erythrocytes was suppressed. Electron microscopy of these immature erythroblasts revealed monosomes rather than the usual polyribosomes in the cytoplasm. RNA histochemistry revealed a greater number of intermediate differentiating erythroblasts with pyronin‐positive cytoplasm than those in the controls and revealed also a dose‐dependent relationship between the number of polychromatic erythroblasts with positive pyronin staining and the controls. These findings suggest that all‐trans‐retinoic acid destroys the messenger RNA system, resulting in an inability to produce hemoglobin.
Mechanism for the removal of residual cytoplasm from spermatids during mouse spermiogenesis
Authors: Sakai Yasuhiro , Yamashina Shohei
Published: February 2005

During spermiogenesis, cytoplasmic processes of Sertoli cells invade spermatid cytoplasm to form a canal complex (Sakai et al., 1988). Thin tubules are formed from the canal complex and intertwine with each other to give rise to the “mixed body.” In the present study, analysis of the changes undergone by the intertwining thin tubules indicated that they contribute to the removal of cell organelles from spermatid cytoplasm.

Intertwining thin tubules were first detected at step 13. By step 15, their number had greatly increased. In the present study, the membranes of the intertwinging thin tubules were clearly observed to be continuous with the spermatid plasma membranes. Thus, the mixed body possibly may be formed as a long pit of the spermatid plasma membrane situated close to the invading Sertoli cell process. With the progress of spermiogenesis, the lumens of the intertwining thin tubules gradually became swollen, and the intertwining swollen tubules fused with each other so that the spermatid cytoplasm enclosed by the intertwining swollen tubules isolated into fragments. This fragmented cytoplasm, which contained a large amount of endoplasmic reticulum, became spherical. Small branches of the invading Sertoli cell processes entered into the lumens of the intertwining swollen tubules and occupied their interior to the point that, finally, they completely engulfed the fragmented spermatid cytoplasm. Because the invading Sertoli cell processes were continuous with Sertoli cell bodies surrounding a spermatid at this step, it is possible for the fragmented cytoplasm to be transported into the latter by way of the invading Sertoli cell processes.
Embedding prolene for the development of fiducial markers
Authors: Johnson Carole L. , Underwood Robert A. , Holbrook Karen A.
Published: February 2005

A simple, inexpensive method is described for embedding Prolene with tissue samples to provide landmarks for fiducial points to align serial sections in tissue reconstructions. Prolene is a monofilament suture material that can be easily sectioned with diamond knives to provide circular markers in each section. The sections are photographed, the negatives are projected through an enlarger and the contours, Prolene circles, and scratches from the diamond knife are traced onto paper. These landmarks establish a framework for assigning fiducial points that are necessary for the correct alignment of the contours. No special equipment is needed for embedding the Prolene and the method is adaptable for both automated and nonautomated computer systems. An example of this method for tissue alignment is given using embryonic limb tissue to determine the spatial organization of developing blood vessels as demonstrated by computer reconstruction.
Radioautographic study of [3H]mannose utilization during cementoblast differentiation, formation of acellular cementuum, and development of periodontal ligament principal fibers
Authors: Cho Moon‐Il , Garant Philias R.
Published: February 2005

The formation of acellular cementum and the deposition of [3H]mannose‐labeled extracellular matrix were studied in 14‐day‐old Sprague‐Dawley rats. The sequential events of cementogenesis and periodontal ligament formation observed by light and electron microscopy were described from the stage of an intact root sheath to postcementogenesis. Ultrastructural examination of cementoblasts and periodontal ligament fibroblasts revealed [3H]mannose labeling of the Golgi apparatus at 10 minutes, collagen secretion granules at 30 minutes, and the extracellular matrix beginning at 30 minutes. The extracellular matrix between cementoblasts and dentin was heavily labeled at 1 and 4 hours. Newly formed principal fibers of the periodontal ligament were also heavily labeled at 4 hours. Fully differentiated cementoblasts exhibited the largest sectional profiles and the highest number of silver grains per unit area of cytoplasm. The morphologic and radioautographic data suggest that during the formation of acellular cementum, the cementoblast phenotype is expressed for a short period of time, after which cementoblasts appear to mix with the fibroblasts of the periodontal ligament.
Development of spermatozoa in the rhea
Authors: Phillips David M. , Asa Cheryl S.
Published: February 2005

We have examined the ultrastructural changes that take place during spermiogenesis in the rhea. Spermatozoa are characterized by a curved head a midpiece. A thin rod extends from the anterior tip of the spermatozoon through the center of the nucleus. A 3‐μ‐long distal centriole occupies the entire midpiece. The principal piece is characterized by a small fibrous sheath and tiny dense fibers that are only observed in the region of the principal piece, which is immediatley behind the annulus. During development a circular manchette surrounds the nucleus of young spermatids. Later the microtubules of the circular manchette become reoganized into a longitudinal manchette. A long distal and short proximal centriole are observed in early round spermatids. The distal centriole becomes associated with the plasma membrane. Later the proximal centriole is observed in association with the nucleus. The area around the centriole pair then accumulates dense material, which is associated with either the centrioles or the circular manchette. The longitudinal manchette forms and then dissappears and mitochondria subsequently associate with the distal centriole. The long centriole of the rhea enables this species to develop a midpiece similar to the midpiece of mammalian sperm without the complex intercellular movements that characterize mammalian spermiogenesis.
Morphogenesis of the secondary palate in mouse embryos with special reference to the development of rugae
Authors: Sakamoto Michiko Kamimura , Nakamura Kosyo , Handa Jun , Kihara Takahide , Tanimura Takashi
Published: February 2005

Morphological studies of secondary palate formation, with special reference to the development of rugae, were carried out on Jcl:ICR mouse embryos. Three rugae were observed on the anterior part of the future oral surface of the vertically developing palatal shelves in 13‐day embryos. Rugae increased in number as the development of the palatal shelves proceeded, and five to six prominent rugae were observed in 14‐day embryos just prior to shelf elevation. The folding of these five to six rugae progressed in conjunction with the formation of a sharp, valley‐like groove at the base of the anterior two‐fifths of the vertical palatal shelves. As palatal shelves elevated, the groove disappeared gradually, and, accordingly, the folding of rugae loosened. In the groove region, the superficial epithelial cells were roundish, while the basal ones were elongated. Such characteristic features were no longer observed when the disappearance of the groove was completed. Eight rugae were observed on the future hard palate of 14‐day embryos with already completed palatal fusion. An additional ruga was frequently found in 15‐day embryos, and the pattern then was almost the same as that of an adult. Epithelial thickening and condensation at the rugae region, as well as mesenchymal condensation under the epithelium of the rugae, were confirmed in embryos both before and after elevation of the palatal shelves. There is a possibility that structural characteristics observed in the epithelial and mesenchymal cells of the rugae and groove regions may be related to palatal shelf elevation.
Differential expression of galactose and N‐acetylgalactosamine residues during fetal development and postnatal maturation of rat glomeruli as revealed with lectin conjugates
Authors: Laitinen Liisa , Lehtonen Eero , Virtanen Iso
Published: February 2005

A battery of fluorochrome‐ or peroxidase‐coupled lectins, reacting with α‐or β‐galactose (Gal), terminal N‐acetylgalactosamine (GalNAc), or Gal‐(β1‐3)‐GalNAc residues, was used to study the emergence and distribution of cellular glycoconjugates in developing and adult rat glomeruli. Neuraminidase pretreatment of the specimens was applied to monitor the maturation of the glomerular sialogly‐coprotein coat.

In the adult glomeruli, the lectin conjugates applied reacted sparsely or not at all, but most of them showed an increased reactivity with podocytes and/or the glomerular basement membrane after neuraminidase treatment. In the embryonic glomeruli, lectins reacting with β‐Gal residues prominently bound to the basement membranes, as revealed in double‐staining with laminin antibodies. This reactivity decreased first during late postnatal development. Some terminal Gal‐(β1‐3)‐GalNAc residues were noted in the earliest podocytes, but obviously soon became covered by sialylation. Furthermore, the developing podocytes prominently displayed α‐Gal residues, as marked by Maclura pomifera (MPA) and Jacalin reactivities but not by the GSA‐I conjugates. During postnatal maturation these reactivities also decreased. The GalNAc‐specific Helix pomatia (HPA) and Helix aspersa (HAA) agglutinins bound to basement membranes of evolving podocytes but later revealed in the podocytes only a Golgi‐like cytoplasmic reactivity. These two lectins showed a marked difference in their binding to tubular basement membranes.

In lectin blotting experiments of electrophoretically separated polypeptides transferred onto nitrocellulose, the peanut agglutinin (PNA) and MPA conjugates revealed upon neuraminidase treatment a broad Mr 140,000 polypeptide, compatible with podocalyxin, both in isolated developing and adult glomeruli. The MPA conjugate revealed a similar polypeptide in developing glomeruli, even without neuraminidase treatment. Similar experiments with the HPA and HAA conjugates revealed different polypeptides in both adult and developing glomeruli.

Obviously, in the rat kidney the maturation of the podocyte sialoglycoprotein coat and the glomerular basement membranes are multiphasic processes that continue even during late postnatal development.