bluuebunny/crossref_metadata_2025 huggingface dataset:
Association of the cardiac neural crest with development of the coronary arteries in the chick embryo
Authors: Waldo Karen L. , Kumiski Donna H. , Kirby Margaret L.
Published: February 2005

Background: Chick coronary arteries orginate as penetrating channels from a subepithelial peritruncal ring into the wall of all three aortic coronary sinuses. Two of these capillaries develop a muscular wall and become the definitive coronary arteries. Since cardiac neural crest (CNC) contributes ectomesenchyme to the tunica media (TM) of the aortic arch vessels, we wished to learn if the CNC also contributes to the media of the coronary arteries and if CNC plays an inductive role in determining the site of aortic penetrations and influences which channels persist to hatching.

Methods: Quail‐to‐chick chimeras were made by bilaterally removing the chick CNC and replacing it with quail CNC. The chimeras and unoperated controls were collected on embryonic days (ED) 7–18, fixed in Carnoy's fixative, serially sectioned, stained with Feulgen‐Rossenbeck stain, and analyzed. Several ED 18 controls and chimeras were also stained with Gomori's trichrome stain, or labeled with antineurofilament or antivascular smooth muscle alpha actin.

Results: The TM of the coronary arteries and the aortic coronary sinuses did not consist of CNC cells. The media of the surviving coronary arteries was disrupted by clusters of CNC cells scattered in the wall of the base of the coronary artery on ED 14 and 18. Persisting coronary arteries were always associated with large neural crest‐derived parasympathetic ganglia near their origin. Branches from parasympathetic nerves entered the base of the coronary arteries where the clusters of neural crest cells were located. Quail cells were also associated with tiny vessels exiting the ostia of the coronary arteries and traveling in the outer aortic wall. Labeling with antibodies confirmed a disruption of the TM at the base of the coronary arteries, and showed innervated clusters of quail cells in the disrupted part of the TM.

Conclusion: Although the TM of the coronary arteries and the aortic coronary sinuses contained no CNC cells, clusters of innervated quail cells disrupted the TM at the base of the coronary arteries. CNC does not appear to induce capillary penetration direclty; however, the exclusive association of CNC‐derived parasympathetic ganglia and nerves with persisting coronary arteries suggests that the presence of parasympathetic ganglia is essential to the survival of the definitive coronary arteries. CNC cells may also be associated with the development of the aortic vasa vasorum. © 1994 Wiley‐Liss, Inc.
Effects of distribution of muscle fiber length on active length‐force characteristics of rat gastrocnemius medialis
Authors: Ettema Gertjan J. C. , Huijing Peter A.
Published: February 2005

Background: The length‐force curve of mammalian skeletal muscle is often wider than expected on basis of the optimum length of the muscle fibers. Two important effects may explain this discrepancy: muscle pennation and distribution of fiber lengths in the muscle. In the present study of the effects of a Gaussian distribution of fiber lengths on muscle length‐force characteristics were investigated in rat gastrocnemius medialis.

Methods: Fiber length‐force characteristics and parameter values of the Gaussian distribution were derived from literature data (Stephenson et al., 1989, J. Physiol., 410:351–366; Heslinga and Huijing, 1990, J. Morph. 206:119–132; Zuurbier and Huijing, 1993, J. Morphol., 218:167–180). Three different constructions of the distribution model were compared with experimental data. Pennation effects were incorporated in the model.

Results: Two constructions gave reasonably good results: (1) the model with a fiber optimum distribution, in which fibers acted at the same absolute length at a given muscle length; (2) the model in which fiber optimum length was uniform but absolute length at a given muscle length was distributed.

Conclusions: In rat gastrocnemius medialis, the magnitude of the effects of these distributions is similar to pennation effects. The current results help to explain the relative wide working range of skeletal muscles in human movement and the differences in specific muscle tension as affected by muscle type, species, and age. © 1994 Wiley‐Liss, Inc.
Middle‐ear development VI: Structural maturation of the rat conducting apparatus
Authors: Zimmer Wayne M. , Rosin Deborah F. , Saunders James C.
Published: February 2005

Background: The contribution of middle‐ear development to the overall development of hearing has not been explored in great detail. This presentation describes the maturation of conductive elements in the rat middle ear, and provides the basis on which future studies of middle‐ear functional development will follow.

Methods: The middle‐ear apparatus was examined at nine different ages (between 1 and 80 days postpartum) in Long Evans rats. At each age elements of the conducting apparatus were observed with either light or scanning electron microscopy (SEM), and quantitative measurements were made from video enhanced photomicrographs. Tympanic membrane area and cone depth, the length of the malleus and incus arms, ossicular weight, stapes foot plate and oval window areas, and bulla volume were all measured. Development of the area and lever ratios were derived from these measurements. The data were fitted to exponential equations and the time in days required to reach 90% of the adult level determined.

Results: The pars tensa achieved 90% of total area by 17 days. The oval window achieved the 90% criterion by 13 days, while the area ratio was within 10% of its adult size by 8 days. The ossicles took between 26 and 34 days, while bulla volume took 59 days to reach the 90% level.

Conclusions: Middle‐ear growth was very orderly and systematic in the data reported. When maturation of the area ratio was considered against development of the endocochlear potential or the round window compound action potential, it was clear that the growth of this important aspect of the middle ear preceded the onset of cochlear function. © 1994 Wiley‐Liss, Inc.
Mucous droplets with multiple membranes in the accessory submandibular glands of long‐winged bats
Authors: Tandler Bernard , Phillips Carleton J. , Pinkstaff Carlin A.
Published: February 2005

Background: Certain species of bats possess two sets of submandibular glands, namely, principal and accessory. The ultrastructure and histochemistry of the accessory submandibular gland was examined in three species of long‐winged bats.

Methods: Specimens of Miniopterus schreibersi and M. Magnator were live‐trapped in Thailand, and of M. inflatus were live‐trapped in Kenya. For electron microscopy, accessory submandibular lands were initially fixed in triple aldehyde‐DMSO, postfixed in osmium tetroxide, and embedded in Epon‐Maraglas. A portion of the glands collected in Thailand (M. schreibersi and magnator) was fixed in buffered formalin and embedded in paraffin. Sections of the latter material were subjected to a battery of histochemical tests for glycoconjugates.

Results: Although in all three species the accessory submandibular glands have normal histological structure, the glands in two, M. schreibersi and M. magnator, were distinguished by possessing mucous droplets of unusual morphology. These droplets, whose identity as mucous was confirmed by histochemical tests for glygoconjugates, are delimited by maniflod membranes: up to 10 in M. Schreibersi and fewer, but still multiple, in M. magnator. In both species, the entire array of surface membranes may fold inward in the fashion of mitochondiral cristae, forming packets of membranes, many of which have the spurious appearance of floating free in the droplet matirix. These multipartite limiting membranes appear to originate simply by Golgi saccules and moderately large, flattened Golgi vesicles repeatedly wrapping themselves around the surface of nascent mucous droplets. During exocytosis, the outermost membrane of each mucous droplet contacts the luminal membrane, this barrie ruptures, then the remainder of the droplet—multiple membranes and matrix—either flow into the lumen or are cast out in toto. In either case, a great deal of membrane phospholipid is added to the salivea. This salivary lipid may permit these bats to consume insects that normally are able to repel predators with chemical defenses that make them unpalatable. The thrid species that we studied, M. inflatus, has mucous droplets of normal appearance, i.e., they have only one limiting membrane.

Conclusions: The varying structure of mucous secretory products among the species of Miniopterus provides important clues as to the evolution of this genus as well as to the evolution of secretory cells in general. © 1994 Wiley‐Liss, Inc.
Light and TEM study of nonregenerated and experimentally regenerated scales of Lepisosteus oculatus (holostei) with particular attention to ganoine formation
Authors: Sire Jean‐Yves
Published: February 2005

Background: The structure of nonregenerated and experimentally regenerated scales of the holostean fish Lepisosteus oculatus and the events taking place before and during ganoine depostition on the scale surface were studied. The aim of this study was to answer the question of the origin of the ganoine in lepisosteids, the scales of which are devoid of dentine, and to compare them to ganoine formation in polypterid scales and to enamel formation in teeth.

Methods: Two adult specimens were used and the scale structure was studied using light and transmission electron microscopy. Regeneration was used as an alternative to the lack of developmental stages and to induce ganoine deposition on the scale surface.

Results: Nonregenerated scales are composed of a thick, avascular bony plate capped by ganoine that is covered either by the epidermis or by dermal elements. The ganoine surface is separated from the covering soft tissues by an unmineralized layer, the ganoine membrane. During the first 2 months of regeneration, the bony plate forms. It differs from the bony plate of nonregenerated scales only by its large, woven‐fibered central region and by the presence of numerous vascular canals. Shortly before ganoine deposition, the osteoblasts cease their activity and an epithelial sheet comes to contact them and spreads on the bony surface. This epithelial sheet is connected to the epidermis by a short epithelial bridge only and is composed of two layers: the inner ganoine epithelium (IGE), in contact with the bone surface and composed of juxtaposed columnar cells that synthesize the ganoine matrix, preganoine; the outer ganoine epithelium (OGE), composed of elongated cells, the surface of which is separted from the overlying dermal space by a basal lamina. Isolated patches of preganoine are deposited by the IGE cells in the upper part of the osteoid matrix of the scale. The interpenetrated preganoine and osteoid matrices constitute an anchorage zone, between ganoine and bone. Preganoine patches fuse and a continuous layer of preganoine is progressively synthesized by the IGE cells. Preganoine progressively mineralizes to become ganoine.

Conclusions: The processes of ganoine formation are similar to those known for the ganoine in the polypterid scales and to those described for enamel deposition in teeth. Ganoine is enamel. © 1994 Wiley‐Liss, Inc.
Distribution of macrophages in the mouse uterus from one day to three months after parturition, as defined by the immunohistochemical localization of the macrophage‐restricted antigens F4/80 and macrosialin
Authors: Brandon Janet M.
Published: February 2005

Background: The morphology of placental detachment sites and the distribution of macrophages were studied in the mouse uterus from day 1 to 3 months post partum.

Methods: Uterine morphology was studied using H&E and Mallory's Trichrome staining. Macrophages were identified using the macrophage‐restricted antigens F4/80 and FA/11 and the leukocyte β2‐integrin CR3 (Mac‐1) which is also expressed by neutrophils.

Results: The post‐partum wound was infiltrated by large numbers of CR3+ F4/80+ FA/11+ macrophages, and CR3+ neutrophils. The wound resolved rapidly and no inflammatory infiltrate or necrotic tissue was seen by day 5 post partum. The area of the detachment wound and the site of the metrial gland of pregnancy resolved into a structure, here called a postpartum nodule, which persisted for at least three months. The post‐partum nodule consisted of an outer layer of collagen around a group of nodule‐specific cells which could be divided into haemosiderin‐ and lipid‐bearing phenotypes. The lipid‐bearing nodule cells were not found after day 20 post partum. Nodule cells were FA/11+ at all times and also expressed leukocyte common antigen. Expression of CR3 and F4/80 was found on nodule cells up to day 9–10 post partum. CR3 expression was found only occasionally after day 10.F4/80 expression was downregulated from day 9–10 to day 20 but was found consistently after day 20. Implantations of second and subsequent pregnancies are known not to occur in the immediate vicinity of post‐partum nodules and nodules from successive pregnancies were seen to be separate within the uterus.

Conclusions: Since the endometrial area in the immediate vicinity of nodules is inimical to implantation and nodules consist of a group of macrophages, it can be implied that nodule macrophages are exerting some influence on the endometrium in their vicinity. © 1994 Wiley‐Liss, Inc.
Structural, morphometric, and immunohistological study of the accessory olfactory bulb in the dog
Authors: Salazar Ignacio , Cifuentes José M. , Quinteiro Pablo Sánchez , Caballero Tomás Garcia
Published: February 2005

Background: The study of the morphological, morphometric, and immunohistological characteristics of the accessory olfactory bulb (AOB) in the dog is the main goal of this work.

Methods: Horizontal sections of the AOB where stained by four different methods (haematoxilin/eosin, Tolivia, Nissl, and Bielchowsky). The avidinbiotin‐peroxidase complex (ABC) was used, whereas the monoclonal antibodies to neuron‐specific enolase, neurofilaments, glial fibrillary acidic protein, and synaptophysin were selected for the immunohistological study. A computer‐assisted image analysis was employed in order to define the morphometric characteristics of de AOB.

Results: The general morphology of the AOB indicates that it comprises a thick glomerular layer and a thinner internal layer containing mitral/tufted, granular, and glial cells. The mitral/tufted cells have large palestaining nuclei with intensely staining nucleoli. There does not appear to be a clearly defined granular layer. No reactivity with antibodies to neuronspecific enolase or to neurofilaments was observed in any part of the AOB, but there was some reactivity with an antibody to glial fibrillary acidic protein and widespread reactivity with an antibody to synaptophysin.

Conclusions: The stratification of the AOB is simpler and less well defined than that of the main olfactory bulb (MOB), unlike in rodents in which the structure of the AOB corresponds closely to that of the MOB. According to the scale of Frahm and Bhatnagar (1980. J. Anat., 130: 349–365) the AOB of the adult dog has an intermediate position. © 1994 Wiley‐Liss, Inc.
Functional allometry of the semicircular ducts in subterranean mole‐rats Cryptomys (Bathyergidae, rodentia)
Authors: Lindenlaub Thies , Burda Hynek
Published: February 2005

Background: Since the spatial mobility of subterranean mole‐rats is restricted and their skull strongly modified, morpho‐functional regression of their vestibular organ may be expected. On the other hand, vestibular sense may be indispensable for orientation in a world deprived of most external sensory cues. Since vestibular sensitivity is determined by the size of the labyrinth, morphometrical analysis may be employed to assess the sensitivity and to test whether the organ is degenerate or progressively specialized.

Methods: We analyzed the shape and size of the membranous labyrinth of vestibular organs in toto in three species of African subterranean blind mole‐rats of the genus Cryptomys (Bathyergidae) differing in body size yet not in habitats, ways of life, or employed orientation and locomotory strategies. The mechanical sensivity of the cupula was estimated according to Oman et al. (1987. Acta Otolaryngol. (Stockh.), 103:1–13) for each of the three semicircular ducts.

Results: The size and shape of the vestibular organ changed predictably depending on species‐specific (yet not individual) body mass. In some aspects, particularly the cross‐sectional area, the ducts were larger than expected for a mammal of a comparable body size. In all species examined, the anterior semicircular ducts exhibited the highest sensitivity.

Conclusions: The vestibular organs of blind subterranean mole‐rats are not regressed morpho‐functionally. © 1994 Wiley‐Liss, Inc.
Ultrastructural and immunocytochemical study on normal human palmar aponeuroses
Authors: Contri Miranda Baccarani , Guerra Deanna , Vignali Nicoletta , Taparelli Francesca , Marcuzzi Augusto , Caroli Alessandro , Ronchetti Ivonne Pasquali
Published: February 2005

Background: Human palmar aponeurosis can be affected by a fibrotic process whose aetiopathology is unknown. As the organization of that normal tissue has not been completely investigaged, the aim of the present study was to define the ultrastructure of the aponeurosis in order to better understand its biology and behaviour in pathology.

Methods: Bioptic samples from normal subjects of different ages were analyses by optical and electron microscopy and by immunocytochemistry.

Results: The aponeurotic branches consisted of thick, almost parallel collagen bundles containing columns of prominent cells, characterized by long cytoplasmic projections. Cells did not change in number and distribution with age and appeared longer and slighter in the old than in the young subjects. They exhibited plasma membrane almost completely decorated by pinocytic vesicles, intracytoplasmic bundles of thin filaments with zonal thickenings close to the cell membrane, and well‐developed subcellular structures. Cells expressed smooth muscle cell α‐actin, as revealed by immunostaining. The external surface of the plasma membrane was underlined by a discontinuous basement membrane–like structure and by a thick coat of interwoven filaments, highly positive to hyaluronan‐recognizing antibodies. Immunocytochemical analyses revealed that collagen fibrils were positive for collagen types I, III, and VI and that elastin fiber composition was rather complex.

Conclusions: Independently of the age, normal palmar aponeurotic cells show peculiar morphological features and peculiar cell‐matrix interactions, very likely mediated by hyaluronan. These findings indicate that normal aponeurotic cells cannot be regarded as typical tenocytes and suggest the need for a better definition of their phenotype in order to understand their behaviour in pathological processes. © 1994 Wiley‐Liss, Inc.
Immunolocalization of a mesenchymal antigen specific to the gastrointestinal tract
Authors: Calvert Raymond , Millane Ghania , Beaulieu Jean‐François
Published: February 2005

Background: The aim of the present study was to localize, at the fine structural level, a protein found by indirect immunofluorescence to be associated with the mesenchymal tissue (1) closely applied to the intervillus epithelium before the formation of intestinal crypts in the mouse fetus and (2) around intestinal crypts during and after their formation.

Methods: We use a pre‐embedding immunolabeling technique for extracellular matrix molecules, and a monoclonal antibody (Mab) directed against antigen MIM‐1/130.

Results: Immunofluorescence disclosed the presence of antigen 1/130 in the connective tissue closely applied to the epithelium of the gallbladder, pyloric glands, and intestinal and colonic crypts in adult mice. The antigen was absent in all salivary glands, kidney, liver, lung, spleen, and pancreas. At the fine structural level, gold particles in positive organs were associated with the interstitial matrix around collagen fibrils underneath the epithelia; gold particles were completely absent in the basement membranes. In the small intestine, labeling was seen only around crypts from cell position 1 up to the crypt‐villus junction; it was totally absent under the villus epithelium. In order to confirm this particular localization in vivo, Mab 1/130 was administered orogastrically to 9‐day‐old mice: after 3 hours the antibody was found lining the immediate periphery of duodenal crypts as seen by indirect immunofluorescence. In control animals, an anti‐mouse laminin Mab of the same subclass as Mab 1/130 was orogastrically fed using the same protocol: basal laminae were labeled under the epithelium of duodenal villi and crypts and also in the lamina propria, with a decreasing gradient from the top of the villi to the bottom of the crypts.

Conclusion: These observation indicate that the extracellular matrix associated with the epithelium of pyloric glands, of intestinal and colonic crypts, and of gallbladder contains a new antigen whose function remains to be determined. The neonatal mouse hence constitutes a good model to study the role of extracellular matrix components in determining organ differentiation in vivo. © 1994 Wiley‐Liss, Inc.
Observations on the pineal gland of the big brown bat, Eptesicus fuscus: Possible correlation of melanin intensification with constant darkness
Authors: Bhatnagar Kunwar P. , Hilton Frederick K.
Published: February 2005

Background: Our initial observation of the macroscopically pigmented pineal gland of the big brown bat, Eptesicus fuscus, led to this study. Information has been lacking on pigmentation in the pineal and its significance in mammals in general and bats in particular. This report begins to address this situation.

Methods: Bats were examined both in the wild and after exposure to various experimental conditions. The pineals were examined macroscopically as well as with light and electron microscopy. The pigment was identified as melanin by its color, the ultrastructure of its granules, and their reaction with hydrogen peroxide.

Results: Gross observations showed the pineals to be variably pigmented, which were subjectively scored from unpigmented to heavily pigmented. Pineals from bats exposed to a continuous 24 h light regimen or those from a summer population contained very little, if any, externally visible melanin. Such pineals are considered unpigmented in this study. In contrast, pineals from 74% of 156 animals taken together, either subjected to constant darkness or hibernation (simulated or natural), exhibited very heavily pigmented pineals. The pigment in these cases even extended to the juxtapineal meningeal covering. The pineal was pigmented even in a newborn Eptesicus.

Conclusions: The pineal pigmentation in the big brown bat appears to intensify with constant darkness and may vary seasonally. The observation of macroscopically pigmented pineals in some other bats (Myotis lucifugus, Pipistrellus subfiavus, and Lasiurus borealis) suggests that this phenomenon may be of taxonomic value for the family Vespertilionidae (Order Chiroptera). © 1994 Wiley‐Liss, Inc.
Composition of Gomori‐positive inclusions in astrocytes of the hypothalamic arcuate nucleus
Authors: Brawer James R. , Stein Robert , Small Lorne , Cissé Soriba , Schipper Hyman M.
Published: February 2005

Background: Astrocytes within the hypothalamic arcuate nucleus contain Gomori‐positive inclusions that exhibit a nonenzymatic peroxidase activity. The source and composition of these Gomori‐positive inclusions are currently unknown. Recent evidence, derived from cultured astrocytes, suggests that Gomori‐positive inclusions may consist of autophagocytized accumulations of altered mitochondria and that the peroxidase activity is generated by iron or other metals which accumulate in these mitochondria.

Methods: The present study applies electron microscopy, energy dispersive X‐ray microanalysis, and immunocytochemistry in conjunction with confocal microscopy to determine the structure and composition of Gomori‐positive inclusions in vivo.

Results: The results indicate that Gomori‐positive inclusions are heterogeneous structures often associated with microtubules and that they contain conspicuous mitochondrial components. Gomori‐positive inclusions exhibit X‐ray emission peaks for copper and, less often, chromium, either of which could account for the peroxidase activity.

Conclusions: These results support the hypothesis that Gomori‐positive inclusions are autophagosomes in which mitochondria are prominent. © 1994 Wiley‐Liss, Inc.
Scanning electron microscopic studies of reticular framework in the rat mesenteric lymph node
Authors: Ushiki Tatsuo , Ohtani Osamu , Abe Kazuhiro
Published: February 2005

Background: The reticular framework in the lymph node has in the past been studied mainly by light microscopy of silver‐impregnated specimens. The aim of the present study is to understand three‐dimensionally the ultrastructure and organization of the reticular framework better than before.

Methods: The mesenteric lymph nodes of the rat were prepared either an alkali‐water maceration method or a conventional method and were observed in a scanning electron microscope (SEM).

Results: The SEM study of alkali‐water macerated tissues visualized directly the reticular fiber network in the lymph node. The reticular fibers consisted of thin bundles of collagem fibrils. They were continuous with the collagen fibriliar sheaths of blood vessels and lymphatic sinuses as well as with the fibrous capusule, thus acting as a skeleton of the lymph node. The arrangement of the reticulum was variable, depending on individual compartments. The SEM study of conventionally treated tissues, on the other hand, clarified the shape of reticular cells and their relationship with the reticular fibers. The sinus reticular cells connected with the sinus lining cells but separated from the parenchymal reticular cells, indicating that the former two originate from lymphatic endothelial cells. The parenchymal reticular cells varied in shape depending on their locations but essentially shared features with fibroblasts.

Conclusions: The arrangements of the reticular fibers in the parenchyma were closely related to the associated reticular cells, showing the possibility that the reticular cells maintain the shape of the reticular framework suitable for each compartment of the lymph node. © 1995 Wiley‐Liss, Inc.
Regeneration in denervated toad (bufo viridis) gastrocnemius muscle and the promotion of the process by low energy laser irradiation
Authors: Bibikova Anna , Oron Uri
Published: February 2005

Background: It is known that while denervated skeletal muscles have the ability to regenerate, maturation of regenerated myofibres does not take place under these conditions. Denervation also causes elevation of “invasive” and satellite cells, but the role of these cells in the regeneration process after injury to the denervated muscle is still unknown. Low energy lasers have recently been found to modulate and accelerate physiological processes in cells. The aim of the present study was to compare regeneration in denervated and innervated amphibian muscles and to investigate whether this process in denervated muscles can be stimulated by low energy laser irradiation prior to injury in these muscles.

Methods: Denervated gastrocnemius muscles of toads were irradiated with He‐Ne laser (6.0 mW, 31.2 J/cm2) 7 days postdenervation (control muscle received red light irradiation at the same wavelength). Nine days after denervation cold injury was performed on the site of irradiation of both groups of muscles. At 14 days postinjury all muscles were removed and processed for histology and histomorphometric analysis of mononucleated cells, myotubes, and young myofibres in the regenerated zone.

Results: The volume fraction (percent of total injured zone) of the various histological structures in the injured zones 14 days after cold injury in the denervated (9 days prior to injury) muscles did not differ from innervated injured muscles at the same time interval postinjury. The mononucleated cells and myotubes in the laser irradiated muscles comprised 49 ± 4% and 6 plusmn; 1% of the injured area, respectively, which was significantly lower than their volume fraction (67 plusmn; 2% and 11 plusmn; 2%, respectively) in the control muscles. The young myofibres populated 34 plusmn; 4% of the total injured area in the denervated and laser irradiated muscles which was significantly higher than their volume fraction (12 ± 2%) in control denervated muscles.

Conclusions: It is concluded that initial stages of regeneration can also take place in skeletal denervated and injured muscles of amphibians. The kinetics of the regeneration process are identical in denervated and innervated muscles. The process of regeneration in denervated muscles can be markedly enhanced if the muscle is irradiated by low energy laser prior to injury, probably by activation (stimulation of proliferation and/or differentiation) cells in the muscles that are “recruited” and participate in the process of regeneration. © 1995 Wiley‐Liss, Inc.
Morphometry of rat germ cells during spermatogenesis
Authors: De Franca Luiz Renato , Ye Shi‐Jun , Ying Li , Sandberg Megan , Russell Lonnie D.
Published: February 2005

Background: There has never been a study of the components of germ cells as they progress through spermatogenesis.

Method:The structural changes taking place in rat germ cells, from spermatogonia to late supermatids, were studied utilizing morphometric techniues conducted largely at the ultrastructural level.

Results:Volume and surface area parameters for virtually all cellular and subcellular features were obtained for nine periods during the spermatogenic cycle. Virtually of germ cell components show dynamic properties associated with specific phases of their development.

Conclusions: The data provided can be used in an objective wey to characterize structural changes to funcational properties of germ cells. © 1995 Wiley‐Liss, Inc.
Structural changes in the oviductal wall during passage of unfertilized cumulus‐Oocyte complexes in mice
Authors: Sato Eimei , Ando Naoko , Takahashi Yuji , Miyamoto Hajime , Toyoda Yutaka
Published: February 2005

Background: Little information is available on the structural relationship of cumulus‐oocyte complexes and the oviductal Wall during the transport of cumulus‐oocyte complexes.

Methods: To this end, morphological changes of the oviductal wall during the passage of unfertilized cumulus‐oocyte complexes were examined chronologically in ICR mice 25–27 days of age ijnected with PMSG and hCG. Mice were sacrificed at 12, 14, 16, 18, and 24 hr after the injection of hCG to remove oviducts, and the height of mucosal folds, muscle ayers, and epithelial cells waas measured in the serial sectios stained with hematoxylineosin or colloidal iron.

Results: The height of the mucoal fold and muscle layer where cumulusoocyte complexes were located was less tan that of the adjacent portions. At 12–18 hr of hCG injection (∼2–8 hr after ovulation), the ova with surrounding cumulus cells lie free in a wide lumen, and the muscular tissue consists of only 2 or 3 layers of cells, arranged mostly longitudinally. However, a neighboring portion without cumulus‐oocyte complexes, where the folds meet in the middle, appreciably restricts the free space in the lumen. After 24 hr of hCG administration, structural changes in the oviductal wall, where cumulus‐oocyte complexes were located, were no longer aparent. The number of cumulus cells surrounding the oocyte decreased during the passage through the oviduct. AT 12–18 hr after hCG injetion, ∼140 cells were identified in the largest cros section of a cumulus‐oocyte complex, but after 24 hr of hCG administration (∼14 hr after ovuluation), an oocyte was surrounded with only (∼14 hr after ovulation), an oocyte was srrounded with only ∼25 cells.

Conclusions: These results indicate that oocyte‐cumulus cell complexes influence the structure of the oviductal wall during the passage in the oviduct. © 1995 Wiley‐Liss, Inc.
Morphometric analysis of the renal veins
Authors: Satyapal K. S. , Rambiritch V. , Pillai G.
Published: February 2005

Background: Although the vascularistion of the kidney has been the topic of repeated anatomical investgations, statistical analses, and descriptions, it is suprising of find that there is no unanimity in the literature reagarding its detailed morphometry. This information acquires special surgical significance, e.g., ub renal trnasplantation and “shunt” surgery. The purpose of this study was to detail the measurements of the left and rightrenal veins in morphologicallu normal kidneys.

Method: This study detailed the measurments of the renal veins in 100 pairs of morphologically normal cadaveric kidneys. Resub casts of the venous system were prepared and various sagments of the renal veins were measured.

Results: The length and diameters of the renal veins were;‐left:5.9±1.5cm and 1.2±0.2cm and right:2.4±0.7cm and 1.2±0.2cm, respectively. The left renal vein comprised a proximal segment (length:2.6cm;diameter:1.1cm)anda distal segment (length:3.2cm:diameter;1.2cm).

Conclusions: This morphometric analysis of the renal veins, which coroboorates and augments and previous anatomical studies, has embryological and surgical significance. © 1995 Wiley‐Liss, Inc.
Spatial distribution of muscle fibers
Authors: Venema Henk W.
Published: February 2005

The analysis of Gates and Betz (1993 Anat. Rec., 236:381–389) of the spatial distribution of two different populations of muscle fibers in the lumbrical muscle of the rat is discussed. The conclusion that muscle fibers belonging to a single motor unit are distributd at random in most muscles appears to need reconsideration. A new technique is applied to some examples to show that the amount of clustering of fiber types in a muscle cross section can be quantified. © 1995 Wiley‐Liss, Inc.
Expression of blood group‐related glycoconjugates in the junctional and other oral epithelia of rodents
Authors: Mackenzie Ian C. , Dabelsteen E. , Rittman G. , Junggren L. , Toh H.
Published: February 2005

Background: The junctional epithelium (JE) attaches the gingiva to the non‐vital tooth surface and has other unusual properties which protect the underlying periodontal tissues. The JE differs from other gingival and oral epithelia in its unusual expression of cytokeratins typical of both stratifying and of simple èpithelia, a phenotypic pattern possibly related to its specialized functions.

Methods: The patterns of differentiation of rodent gingival and other epithelia were examined using monoclonal antibodies against various glycoconjugates which are expressed on epithelial cell surfaces and provide an alternative marker system for regionally‐differing patterns of cell maturation.

Results: Markers that are typical of basal cells in other stratifying epithelia were expressed by all cell strata of JE. JE lacked differentiation markers typical of other stratifying oral epithelia but showed suprabasal expression of markers typically expressed by simple epithelia and specialized epithelia, such as taste buds.

Conclusions: The phenotype of rodent JE differs from that of other oral epithelia and the pattern of differentiation assessed by its expression of glycoconjugates parallels that for other phenotypic markers, such as cytokeratins. Differentiation of rodent JE is similar to that of human JE. The functional significance of these patterns of expression is not yet clear but the markers characterizing this unusual epithelium in rodents may be associated with its behavior in periodontal disease and of value to experimental studies of its development.© 1995 Wiley‐Liss, Inc.
Structural changes in the oviductal wall during the passage of unfertilized cumulus‐oocyte complexes in mice
Authors: Sato Eimei , Ando Naoki , Takahashi Yuji , Miyamoto Hajime , Toyoda Yutaka
Published: February 2005

Background: Little information is available on the structural relationship of cumulus‐oocyte complexes and the oviductal wall during the transport of cumulus‐oocyte complexes. Then, morphological changes of the oviductal wall during the passage of unfertilized cumulus‐oocyte complexes was examined chronologically in ICR mice 25–27 days of age injected with PMSG and hCG.

Methods: Mice were sacrificed at 12, 14, 16, 18, and 24 hr after the injection of hCG to remove oviducts, and the height of mucosal folds, muscle layers, and epithelial cells were measured in the serial section stained with hematoxylin‐eosin or colloidal iron.

Results: The height of the mucosal fold and muscle layer where cumulus‐oocyte complexes were located was less than that of the adjacent portions. At 12–18 hr of hCG injection (about 2–8 hr after ovulation), the ova with surrounding cumulus cells lie free in a wide lumen, and the muscular tissue consists of only 2 or 3 layers of cells, arranged mostly longitudinally. However, a neighboring portion without cumulus‐oocyte complexes, where the folds meet in the middle, appreciably restricts the free space in the lumen. After 24 hr of hCG administration, structural changes in the oviductal wall, where cumulus‐oocyte complexes were located, were no longer apparent. The number of cumulus cells surrounding the oocyte decreased during the passage through the oviduct. At 12–18 hr after hCG injection, about 140 cells were identified in the largest cross section of a cumulus‐oocyte complex, but, after 24 hr of hCG administration (about 14 hr after ovulation), an oocyte was surrounded with only about 25 cells.

Conclusions: These results indicate that oocyte‐cumulus cell complexes influence the structure of the oviductal wall during the passage in the oviduct. © 1995 Wiley‐Liss, Inc.
In vivo morpho‐functional study of rat gastric mucus secretion
Authors: Sbarbati Andrea , Baldassarri Angela M. , Zancanaro Carlo , Boichelli Andrea , Osculati Francesco
Published: February 2005

Background: Morpho‐functional studies of gastric mucosa are hampered by the lack of a technique allowing direct in situ visualization of the mucus in small living laboratory animals.

Methods: The material covering the gastric surface was studied in vivo in rats by magnetic resonance imaging (MRI) at 4.7 Tesla, and modification of its secretion was evaluated after pharmacological treatment.

Results: In unstimulated animals, the glandular portion of the stomach was lined by a layer of material emitting a signal of high intensity. Administration of 16,16‐dimethyl prostaglandin E2 caused an accumulation of this material within a maximum 30 min after the administration of the drug. At 45 min, gastric emptying occurred and at 60 min, the lumen was almost free of material emitting a signal of high intensity. An increase in the intensity of the signal emitted from the material filling the gastric lumen was found after pentagestrin injection. After 45 min, the intensity of the signal emitted from the material in the gastric lumen decreased. 1H localized spectroscopy showed that after injection of pentagastrin there was an increase in the water proton peak within the gastric lumen. About one hour after stimulation, the water proton peak returned to the basal value.

Conclusions: This study demonstrates that MRI displays gastric mucus in living small rodents and represents a sensitive screening test for pharmacological action on this structure, enabling morpho‐functional studies. © 1995 Wiley‐Liss, Inc.
Parathyroid morphology of the brush‐tail possum, Trichosurs vulpecula
Authors: Haynes Julie I.
Published: February 2005

Backgound: Reviews of the comparitive antomy of the parathyroid glands contain very little or no information on this endocrine gland in marsupials. This paper is the initial report of a broader investigation of the parathyroid glands in marsupials and monotremes.

Method: Nineteen possums Trishosurus vulpecula were used in the study of the anatomy, histology, and ultrastructure of the parathyroid glands. Tissue sections were examined using routine light and electron microscopic techniques.

Results: Parathyroid III is larger than parathyroid IV. The former occurs in the vicinity of the carotid bifurcation; the latter is found in the mediastinum, and in 67% of samples it was observed to be associated with thymic tissue. In parathyroid III specimens, 12.5% had follicles, 25% had cysts, and 16% contained thymic tissue. Ultrastructurally, the majority of specimens consisted of principal cells; no oxyphil cells were seen. Light and dark cells were only seen in glands that had been fixed by perfusion. Junctions between thymic and parathyroid tissues showed intervening epithelial reticular cells, but a basal lamina was not always apparent. In three specimens, cells that resembled water‐clear cells were present. It is proposed that these unusual cells may reflect a state of impaired health in these possums.

Conclusions: Except for the presence of vacuolated cells labelled water‐clear cells, the histology of the parathyroid gland in the possum shows many similiarities to that in many eutherians. © 1995 Wiley‐Liss, Inc.
Spermatozoal ultrastructure in three species of parrots (Aves, psittaciformes) and its phylogenetic implications
Authors: Jamieson Barrie G. M. , Koehler Lawrence , Todd Bethwyn J.
Published: February 2005

Background: DNA‐DNA hybridization studies suggest that Psittaciformes are highly, but not the most, derived nonpasserines. Multilocus protein electrophoresis indicates that cockatoos (Cacatuinae) form a monophyletic lineage distant from the other Australo‐Papuan psittacids (Psittacinae).

Methods: Transmission electron microscope procedures are applied to the spermatozoa of three parrots, in the Cacatuninae and Psittacinae, to investigate these relationships.

Results: Psittaciform sperm have the following characteristics: (1) conical acrosome vesicle; rodlike perforatorium; cylindrical, highly condensed nucleus; proximal and distal centriole embedded in dense material; elongate periaxonemal mitochondrial midpiece, (2) nine dense peripheral axonemal fibers (coarse fibers), (3) no fibrous sheath around the axoneme, (4) mitochondria with linear cristae, lacking intra‐ (or inter‐) mitochondrial dense bodies, (5) restriction of the endonuclear perforatorial canal to the anterior region of the nucleus, (6) a short distal centriole, and (7) nucleus abutting on but not penetrating the acrosome.

Conclusions: (1) These features are tetrapod symplesiomorphies, (2) is an amniote synapomorphy; the fibers differ from those of reptiles in being uniform in size, (3) loss of the fibrous sheath is an apomorphy known elsewhere only in columbiforms, (4) are apomorphies relative to basal aminiotes (Chelonia, Sphenodon, and Crocodilia), (5) is an apomorphic condition shared with other nonpasserines (galliforms and the white‐naped crane) and crocodilians, (6) the latter taxa differ from parrots in a plesiomorphic elongation of the distal centriole, and (7) is a unique apomorphy of parrot sperm relative to other nonpasserines and reptiles. The short midpiece of N. hollandicus distinguishes this cacatuine from the two psittacines. © 1995 Wiley‐Liss, Inc.
Shape, F‐actin, and surface morphology changes during chemotactic peptide‐induced polarity in human neutrophils
Authors: Fernández‐Segura Eduardo , García José M. , Santos Juan L. , Campos Antonio
Published: February 2005

Background: The exposure of human neutrophils to uniform concentrations of chemoattractants, such as N‐formyl peptides, induces morphological cell polarization. In this study we report the temporal sequence of changes in cell shape, F‐actin, and cell surface morphology during cellular polarization induced by N‐formylmethionyl‐leucyl‐phenyl‐alanine (fMLP) in human neutrophils in suspension.

Methods: Neutrophil shape changes induced by 10−8 M fMLP were observed with DIC microscopy. Size and Cellular granularity were analyzed by flow cytometry measuring their forward and side scattered light. To visualize F‐actin distribution, neutrophils were labeled with the fluorescence probe FITC‐phalloidin, and were examined with fluorescence and confocal laser scanning microscopy. Cell surface morphology was assessed with scanning electron microscopy (SEM).

Results: The stimulation of round‐smooth neutrophils with nanomolar concentrations (10−8 M) of fMLP in suspension induced a temporal sequence of morphological changes during cell polarization, characterized by 1) increase in size as determined by forward angle scattered light, 2) rapid redistribution of F‐actin from a diffuse cytoplasmic localization to the cell periphery, and 3) rapid reorganization of cell surface morphological features, with accumulation of plasma membrane in the front of polar cells. Four cell shapes were identified with SEM after stimulation of round‐smooth neutrophils: round‐ridged, round‐ruffled, nonpolar ruffled, and polar cells. These cell shapes were correlated with a cortical localization, focal aggregates, and multipolar distribution of F‐actin. In polar neutrophils, F‐actin became concentrated in the front of the cell.

Conclusions: These findings show the relation between reorganization of the microfilamentous cytoskeleton and modifications in cell shape and surface features during cell polarization induced after fMLP activation in neutrophils. This approach offers a powerful tool for further analysis of receptor distribution in polarized, motile neutrophils. © 1995 Wiley‐Liss, Inc.
Cytoarchitecture of the substantia nigra pars lateralis in the opossum (Didelphis virginiana): A correlated light and electron microscopic study
Authors: Ma Terence P. , Hazlett James C.
Published: February 2005

Background: The substantia nigra has been divided into three subdivisions. However, the cytoarchitecture of one of these subdivisions, the pars lateralis (SNI), has not been previously examined in detail at the light and electron microscopic levels in any species. In the adult opossum, the three nigral subdivisions can be easily distinguished as distinct, rostrocaudally oriented cell groups separated by neuron‐free zones. Thus it was possible to determine the boundaries of the SNI unambiguously. This report covers the results of an examination of the morphology and organization of the SNI in the opossum.

Methods: Material from 13 opossums was used for this study. Eight of the animals had been previously stained for Nissl substance (n=4) or impregnated by the Golgi technique (n=4). The remaining five animals were prepared for electron microscopic studies using standard procedures.

Results: Two cell types were identified on the basis of morphological differences, small and medium‐large neurons. Small neurons (10–18 μm long axis) have large nuclei with moderate amounts of heterochromatin and a thin rim of cytoplasm. They have long (up to 500 μm), spine‐free dendrites. Medium‐large neurons (18–54 μm long axis) have rounded nuclei with electron‐lucent nucleoplasm. Few indentations of the nuclear envelope were observed. The surrounding cytoplasm has dense arrays of organelles. Nissl bodies are particularly prominent in the form of pyramids with their bases at juxtanuclear positions and their apices directed toward emerging dendrites. Dendrites of medium‐large neurons are long (some>1 mm in length), are primarily oriented in the frontal plane, and extend along the dorsal surface of or into the cerebral peduncle. Some cells have dendrites that are moderately spinous, whereas other neurons possess sparsely spinous dendrites. Relatively few synaptic profiles are observed to contact somata and proximal dendrites.

Conclusion: This report provides added morphological support for the idea that the SNI is a distinct subdivision of the substantia nigra, a distinction previously made on the basis of the physiologically characterized relationship between the lateral substantia nigra and orienting behaviors and seizure‐related function. © 1995 Wiley‐Liss, Inc.