bluuebunny/crossref_metadata_2025 huggingface dataset:
Report of a rare human variation: Absence of the radial artery
Authors: Poteat William L.
Published: February 2005

A case of unilateral absence of the radial artery is reported. The arterial system of the specimen was developmentally primitive with the anterior interosseous artery the chief blood supply to the forearm and hand. A “superficial ulnar artery” of small caliber supplemented the supply of the hand. Three large branches of the anterior interosseous artery supplied the hand with the lateral terminal branch replacing the radial artery distal to the wrist. The superficial palmar arch was formed by an anastomosis of the media and lateral terminal branches of the anterior interosseous artery. No deep palmar arch was present, but three palmar metacarpal arteries arose from a perforating artery which branched from a large dorsal branch of the anterior interosseous artery. The median artery was of small caliber and could not be traced beyond the midforearm. Based on this specimen and a review of other forearm and hand arterial variations, it is postulated that the ulnar artery may developmentally precede the median artery.
On nerves and teeth in the lower jaw of the cichlid Tilapia mariae
Authors: Holje L. , Hildebrand C. , Fried K.
Published: February 2005

The anatomy of the teeth and tooth‐related nerves in the lower jaw was examined in the cichlid Tilapia mariae. This was done in order to establish a basis for studies on dental neuroplasticity in a polyphyodont vertebrate. The region of interest was explored in specimens fixed by glutaraldehyde perfusion, and by using X‐ray photography, maceration, scanning electron microscopy, gross dissection, and light microscopic examination of serial sections. The results show that the lower jaw carries some 60–65 functional teeth. In addition, numerous replacement teeth and tooth germs in various stages of development are located in a cavity in the dentary bone. Numerous nerve bundles are present in immediate relation to the dental follicles of tooth germs. Unerupted teeth do not contain light‐microscopically discernible pulpal axons, but the pulps of functional teeth contain myelinated axons. Both perifollicular and pulpal nerve bundles derive from a nerve plexus, which is formed by branches from r. mandibularis trigemini. This nerve is easily accessible to experimental manipulation, where it courses through the adductor mandibulae muscular complex. Thus, the lower jaw of T. mariae seems to represent a suitable system for the study of tooth‐nerve interactions in a polyphyodont species.
Localized vascular regression during limb morphogenesis in the chicken embryo. I. Spatial and temporal changes in the vascular pattern
Authors: Feinberg Richard N. , Latker Carole H. , Beebe David C.
Published: February 2005

Morphogenesis of the vertebrate limb bud depends upon reciprocal interactions between epithelial and mesenchymal tissues. A characteristic limb vascular pattern is essential for normal limb outgrowth. The vascular pattern in the distal portion of the wing bud was examined by ink injection and compared to the sites of cartilage differentiation, as indicated by [35S]‐incorporation.

During development, avascular areas arose in three distinct locations within the vascularized mesoderm. These areas corresponded to the distal skeletal elements, referred to as digits 2, 3, and 4. Incorporation of radioactive sulfate was high in the avascular areas and low in the adjacent vascular tissue. Examination of autoradiographs of ink‐injected limbs suggested that the appearance of avascular regions preceded the accumulation of sulfated cartilage matrix. These results indicate that remodeling of the limb vasculature is related to the formation of the skeletal pattern.
Fiber composition of the rat sciatic nerve
Authors: Schmalbruch H.
Published: February 2005

The rat sciatic nerve originates from the spinal segments L4–L6. It is unifascicular at the trochanter; 5–7 mm distally, the nerve splits into two and then into four fascicles. The tibial portion gives rise to the tibial and the sural nerves, and the peroneal portion gives rise to the peroneal nerve and a cutaneous branch that perforates the lateral hamstring muscles to innervate the proximolateral face of the calf.

The number and type of the axons in these branches were determined in light and electron micrographs of normal nerves, and after de‐efferentiation or sympathectomy. Deafferentiation was technically not feasible because spinal ganglia and ventral roots were supplied by the same vascular plexus.

The tibial nerve contained 1,000 motor and 3,500 myelinated afferent axons, 3,700 sympathetic axons, and 5,400 unmyelinated afferent axons. The peronal nerve contained 600 motor and 1,300 myelinated afferent axons, 1,100 sympathetic axons and 3,000 unmyelinated afferent axons. The sural nerve contained 1,100 myelinated and 2,800 unmyelinated afferent axons; in addition, there were 1,500 unmyelinated sympathetic axons. The cutaneous branch consisted of 400 myelinated and 1,800 unmyelinated afferent axons. Thus, the entire sciatic nerve at midthigh is composed of about 27,000 axons; 6% are myelinated motor axons, 23% and 48% are myelinated and unmyelinated sensory axons, respectively, and 23% are unmyelinated sympathetic axons. The techniques used did not demonstrate sympathetic axons in the cutaneous branch and did not reveal the few motor axons contained in the sural nerve.
Root‐analogue versus crown‐analogue dentin: A radioautographic and ultrastructural investigation of the mouse incisor
Authors: Beertsen W. , Niehof A.
Published: February 2005

The present paper reports on differences between the root‐ and crown‐analogue dentin portions of the continuously growing mouse incisor. Conventional light microscopy and radioautography were used to study dentin formation and the uptake of [3H]‐proline and [3H]‐serine. It was found that, although the dentin apposition rate along the crown‐analogue part (covered by enamel) equalled or slightly exceeded that along the root‐analogue part (covered by cementum), the processing of predentin into dentin was considerably faster in the root aspect.

Comparison of the two dentin portions at the ultrastructural level revealed that differences occurred in the morphology of the secretory granules of the odontoblast layer. Two types of granules were observed: those that were and those that were not loaded with electron‐dense particles of 30 nm diameter. While the former type was most frequent along the crown‐analogue aspect of the incisor, the latter type was particularly found along its root‐analogue aspect. This difference may reflect differences between the two dentin portions in the composition of the noncollagenous matrix.
A quantitative cytochemical analysis of large antral follicles in two types of rat polycystic ovaries
Authors: Zoller Lawrence C. , Axelson John F.
Published: February 2005

Ovaries from normal mature rats, rats injected with testosterone propionate (TP), and from aged rats were removed, and large antral follicles examined by quantitative cytochemical techniques in order to analyze possible enzymatic defects that relate to follicular steroidogenesis. The ovaries from the TP‐injected and the aged rats were polycystic. Lipid deposition was analyzed in frozen sections stained with Sudan black. A microdensitometer was used to measure Δ5‐3β ‐hydroxysteroid dehydrogenase (3βOHD) activity and G‐6‐PD type IH generation in the theca, and in peripheral region, antral region, and corona radiata of large antral follicles. 3βOHD is the enzyme that converts pregnenolone to progesterone. Type IH generation is related to the conversion of androstenedione to estradiol. Lipid droplet deposition was comparable in the three types of follicles. Compared to that in normal preovulatory follicles, 3βOHD activity was similar in identical regions of large antral follicles in TP‐injected rats, but less in the theca and peripheral region of the membrana granulosa of the aged rat. G‐6‐PD type IH generation was less in the peripheral region of large antral follicles of both TP‐injected and aged rats than in preovulatory follicles. Type IH generation was also less in the theca of TP‐injected rats than in the theca of normal rats. This study provides evidence that in spite of their normal appearance, large antral follicles in polycystic ovaries are not physiologically sound. Furthermore, the enzymatic disturbance appears to be different in different types of polycystic ovaries.
Isolation of murine thymic epithelium and an improved method for its propagation in vitro
Authors: Farr Andrew G. , Eisenhardt David J. , Anderson Susan K.
Published: February 2005

A reliable and reproducible method for the isolation and propagation of thymic epithelial cells is described. Thymic epithelial cells from enzymatically dissociated thymus stroma are first enriched by separation on a discontinous Percoll density gradient. The cell fractions enriched for epithelial cells are then cultured with irradiated fibroblasts in Ham's F‐12 nutrient medium. Colonies of cells in these cultures contain keratin and exhibit morphologic characteristics of epithelial cells. When subcultured, the epithelial cells no longer require irradiated fibroblasts as filler cells. Some of the epithelial cells in vitro retain expression of class II (Ia) major histocompatibility antigens. The generation of defined cultures of thymic epithelial cells promises to be useful in defining their role in T cell differentiation.
Age associated increase of C cell follicles in guinea pig thyroid glands
Authors: Kameda Yoko
Published: February 2005

The effect of aging on the formation of C cell follicles was examined in the thyroid gland of guinea pigs at various ages ranging from 1 to 29 months. The C cell follicles were demonstrated with the immunoperoxidase methods by using anticalcitonin and antisomatostatin antisera and with PAS reaction. They were already detected in 1‐month‐old guinea pigs but in low number. Thyroid glands from 1‐ to 14‐month‐old animals contained only a small number of C cell follicles and did not reveal the age‐related increase. In aged guinea pigs (20‐ to 29‐month‐old), a dramatic increase of C cell follicles was found, about 13 times as high as the number of other age groups. The C cell follicles through all age groups were present in large clusters of C cells. In the aged guinea pigs, nodular large aggregates of C cells regarded as C cell hyperplasia occurred and numerous C cell follicles were formed in the large cell aggregates. Thus, the conspicuous increase of C cell follicles in aged animals was associated with a proliferative abnormality of C cells. The C cells forming follicles showed moderate to weak immunoreactivity for calcitonin, whereas they showed very intense immunoreactivity for somatostatin. In addition, the colloidlike and flocculent materials stored in the follioular lumina, which were consistently PAS‐positive, were weakly immunoreactive to somatostatin but nonreactive to calcitonin.
Localization of immunoreactive keratins in cyst epithelium of chick ultimobranchial glands
Authors: Kameda Yoko , Ito Miyoshi , Tagawa Takasuke
Published: February 2005

The cyst structures of chick ultimobranchial glands were studied by electron microscopy and immunocytochemistry to characterize the type of intermediate‐sized filaments present in the cells lining cyst lumina. Electron microscopy showed that the majority of the lumen‐bordering cells contained extensive mesh‐works of intermediate‐sized (7–11 nm) filaments, many of which were arranged in bundles. Apical regions of C cells directly bordering on cyst lumina were also filled with thinner (5–6 nm) filaments. Immunoperoxidase staining showed that the majority of cyst epithelial cells were stained intensely with anti‐keratin antiserum, but not with anti‐neurofilament antiserum, which is a specific marker for neuronal differentiation. The cyst epithelium also showed moderate‐to‐weak immunoreactivity for actin. Subsequently, the differentiation and maturation of cyst structures related to intermediate filament expression wore studied. In 18‐day‐old chick embryos, keratin immunoreactivity began to appear in the cell clusters destined to form cysts and in the primordial cysts with small cavities. At this time, fine networks of intermediate filaments were already detected in the cells lining the cystic cavities. At 1 day after hatching, the cysts became a consistent feature of ultimobranchial glands. Intermediate filaments associated in bundles were observed, and the intensity of immunostaining for keratins increased. Thereafter, with progressive enlargement of cysts, numbers of intermediate filaments and intensity of keratin immunoreactivity gradually increased with age. Thus, the data indicate that in cyst epithelium keratin filaments are highly organized and may confer the structural strength necessary for cells lining cyst lumina.
Cell size and shape changes in the myoepithelium of the mammary gland during differentiation
Authors: Emerman Joanne T. , Vogl A. Wayne
Published: February 2005

We have studied changes in myoepithelial cell size and shape during different stages of mouse mammary gland differentiation by using the fluorescent probe for actin NBD‐phallacidin. Pieces of mammary tissue were fixed, mounted on slides, permeabilized with cold acetone (−20°C), and then treated with nitrobenzoxadiazole‐phallacidin. Myoepithelial cells lining ducts of glands at all stages of development are spindle‐shaped structures oriented parallel to the long axis of the duct at the base of the luminal epithelium. In virgin animals, myoepithelial cells also occur as linear tracts oriented parallel to the long axis of small projections along the sides of ducts and terminal end buds. In early pregnancy, small stellate‐shaped cells begin to appear around presumptive secretory units. By late pregnancy, larger star‐shaped units of intense fluorescence appear at the base of alveoli. During lactation, both cell bodies and cell processes further enlarge as these interlacing stellate‐shaped cells encompass the expanded alveoli. In regressing glands, cell size decreases and the processes appear to retract. Although alveoli are virtually absent in the multipartate resting gland, myoepithelial cells remain around lateral buds of ducts. These myoepithelial cells have two distinct shapes: (1) small star‐shaped cells capping the buds and (2) spindle‐shaped cells oriented parallel to the long axis of the buds. A comparison of myoepithelial cell shape in virgin mice and nulliparous women indicates a more developed cell in the human gland at this stage of development. Intact segments of mammary gland combined with NBD‐phallacidin as a probe for actin provide an ideal system for future studies of the control of myoepithelial cell size and shape and their influence on cell functions.
Chorda tympani innervation of anterior mandibular taste buds in the chicken (Gallus gallus domesticus)
Authors: Ganchrow Judith R. , Ganchrow Donald , Oppenheimer Miriam
Published: February 2005

While the mammalian chorda tympani innervates taste buds on the anterior two‐thirds of the tongue, the chorda tympani of chickens does not enter the tongue, but rather is reported to supply the oral epithelium of the lower beak subjacent to the tongue. This study in the chicken investigated whether the integrity of taste buds in the lower beak is normally dependent upon innervation by the chorda tympani. Following unilateral ligation and removal of a large section of the chorda tympani, animals were sacrificed at 11, 14, and 21 days postoperatively. Oral tissue between the lingual frenulum and beak tip was serially examined, and the presence of each bud was recorded, noting the point at which the bud opened into the oral cavity. No buds were observed on the operated side in any of the cases, while the average bud count on the unoperated side was 33 ± 10 (SD). On the unoperated side, taste buds were generally associated with anterior mandibular salivary gland ducts that reached surface epithelium and opened into the oral cavity. On the operated side, the cellular organization adjacent to gland ducts and in duct‐free epithelium appeared as in control (i.e., bud‐free) epithelium. The number of salivary gland duct openings into the oral cavity was equivalent on the operated and control sides. It is concluded that the chorda tympani of chickens innervates taste buds in the anterior lower beak epithelium and that it functions to maintain the structural integrity of these buds.
Papillary morphology of the tongue of the American chameleon:Anolis carolinensis
Authors: Rabinowitz Terry , Tandler Bernard
Published: February 2005

Based on regional differences in surface morphology, the dorsum of the tongue ofAnolis carolinensiscan be subdivided into four distinct zones. The first quarter of the tongue is relatively smooth, whereas the second and fourth quarters are festooned with closely packed cylindriform papillae, which are covered by typical parakeratotic stratified squamous epithelium. The third quarter of the tongue is covered by papillae of novel morphology that we have named “plumose papillae.” These are composed of a slender connective tissue core covered by stratified squamous epithelium from whose surface numerous elongated cells radiate. These “plume cells” are about 30–40 μm long and have an extremely irregular nucleus in their expanded terminus. Their stalks are affixed by desmosomes to the deeper cells of the epithelium, and their free surfaces are covered by intricately patterned microplications. Their cytosol contains a dense web of 100‐Å cytofilaments that may be involved in maintaining the peculiar morphology of the cells. Regardless of type, all lingual papillae ofA. carolinensiscontain a single longitudinally oriented skeletal muscle fiber that originates from the underlying lingual muscles, raising the possibility that the papillae can be moved at will. The plumose papillae and their retinue of plume cells are unique morphological structures that may be important in mastication and deglutition of food.
Histochemical types and sizes of fibers in the rectus abdominis muscle of guinea pig: Adaptive response to pregnancy
Authors: Costerbosa G. Lalatta , Barazzoni A. M. , Lucchi M. L. , Bortolami R.
Published: February 2005

Effects of pregnancy stimulation upon histochemically assessed myofibrillar ATPase and muscle fiber diameters were analysed in the rectus abdominis (RA) muscle of guinea pig. Samples of the muscle were taken at 30, 40, 50, 60, and 70 days of pregnancy and compared with samples of the same muscle taken from nonpregnant guinea pigs. Changes in muscle fiber proportions were noted through the course of pregnancy. Starting from 50 days of gestation an increase in type I fibers and a decrease in type IIB fibers were noted. Increase in muscle fiber diameters was also observed in type I, IIA, and IIB fibers. In addition, the RA muscle of the male guinea pig was compared with that of the female guinea pig and showed more type IIA and less type IIB fibers and all the three fiber types were larger than those of the female.
Automatic morphometric analysis of skeletal muscle fibers in the aging man
Authors: Poggi Paola , Marchetti Carla , Scelsi Roberto
Published: February 2005

A qualitative and quantitative analysis of M. vastus lateralis fibers from 40 male sedentary subjects, ranging in age from 30 to 89 years, was carried out by light and electron microscopy and by an automatic Interactive Image Analysis System. Biopsies for enzyme histochemical and ultrastructural studies were taken from subjects subdivided into four age groups: 30–50, 60–70, 71–80, and 81–89 years. Attention was focused on the fiber type size and distribution, the size and the amount of mitochondria, and the amount of lipid droplets. Main changes observed in the four age groups are indicative of a sequence of events within senescent skeletal muscle fibers. With increasing age the enzyme histochemical reactions reveal changes in fiber type distribution characterized by decrease in muscle fiber diameter and by type I fiber predominance.

Type II fiber atrophy is consistent. Type I fiber predominance seen in older subjects could be related to a selective decrease of type II fibers with age. It also suggests a possible conversion of type II fibers to type I fibers. Lipid droplet percentage per fiber area increases, while mitochondrial size and mitochondrial percentage per fiber area decrease with age. It is possible that energy requirements decline with age and that the decrease in mitochondrial size and percentage represents a response to a reduced metabolic demand.
Development of wing‐bud‐derived muscles in normal and wingless chick embryos: A computer‐assisted three‐dimensional reconstruction study of muscle pattern formation in the absence of skeletal elements
Authors: Lanser Mark E. , Fallon John F.
Published: February 2005

The mechanisms whereby the normal pattern of muscles within the developing chick limb bud is generated are largely unexplored. It has been proposed that the muscle pattern is established independently of the pattern for the limb skeletal elements to which the muscles normally attach (Shellswell and Wolpert: “The Pattern of Muscle and Tendon Development in the Chick Wing.” In: Vertebrate Limb and Somite Morphogenesis. Cambridge University Press, Cambridge, pp. 71–86, 1977). To further examine this possibility we studied the formation of the proximal wing muscles in normal and wingless chick embryos. The muscles of the shoulder region (including the pectoralis) arise as part of the dorsal and ventral premuscle masses of the developing limb bud. These secondarily migrate out of the limb to take origin from the pectoral girdle while inserting onto the humerus (Sullivan: Aust. J. Zool., 10:458–516, 1962). With rare exceptions, wingless embryos have complete absence of wing skeletal elements, but they may possess more than 40% of the normal volume of wing‐bud‐derived muscles. The muscles that remain in wingless embryos are primarily shoulder muscles, and to a varying extent, the pectoralis. The question we sought to answer was whether in wingless embryos the proximal wing muscles could form a normal pattern in the absence of the humerus and distal wing skeletal elements. By examining three‐dimensional reconstructions of the proximal wing region in normal and wingless embryos, we found that the initial subdivision of the dorsal and ventral premuscle masses proceeded normally in the absence of the wing skeleton. This resulted in a grossly normal pattern of proximal wing muscles despite the absence of wing skeletal elements. However, some subsequent cleavages of individual muscles within premuscle mass divisions did not occur in wingless embryos. This suggests that the skeleton may be required for this step in muscle morphogenesis to occur. We also observed that the wing‐budderived muscles in wingless embryos were nearly always anchored to the pectoral girdle at both ends. Sometimes this resulted in muscles making abnormal tendonous fusions with other muscles derived from the opposite (i.e., dorsal or ventral) premuscle mass. Therefore, attachment to the skeleton may be important for some facet of muscle development. Finally, the supracoracoideus muscle was absent in all but one wingless embryo we examined in the present study. In that one, it was substantially reduced in volume compared to normal. Despite the absence of this muscle, the space normally occupied by the supracoracoideus was maintained beneath the pectoralis. This observation suggests that the form, or shape, of a muscle may be established within the connective tissue in the absence of the muscle itself.
Distinct types of encapsulated sensory corpuscles in the oral mucosa of the dog: Immunohistochemical and electron microscopic studies
Authors: Tachibana T. , Ishizeki K. , Sakakura Y.
Published: February 2005

The types, structure, and distribution of encapsulated sensory endings that have lamellar investments in the oral mucosa and vermilion border of the lip of adult dogs were studied by light and electron microscopy. Immunohistochemistry for cholinesterase was used to identify the corpuscules by light microscopy. Two different types of corpuscular end‐organs containing definite inner cores were distinguished. One was a typical, simple corpuscle, which contains only one, but sometimes two, inner cores composed of densely piled cytoplasmic lamellae surrounding a central axon terminal. The other type was characterized by the coexistence of convoluted inner cores, arborized free endings, and thin nerve bundles within a perineural capsule; we term this type “compound corpuscle.” The ultrastructure of the inner cores in compound corpuscles was similar to that of mature, simple corpuscles. The arborized free endings in the compound corpuscles usually contained an accumulation of mitochondria and small clear vesicles. The compound corpuscles were frequently encountered in the vermilion border of the lip and in the labial and buccal mucosae but were rare in the masticatory mucosa of the gingiva and hard palate. From the results, it was concluded that the compound corpuscle is a distinct type of the sensory end‐organ containing inner cores.
Regulation of the density of spermatogonia in the seminiferous epithelium of the Chinese hamster: II. Differentiating spermatogonia
Authors: De Rooij D. G. , Lok D.
Published: February 2005

In this study the yield of the proliferation of the differentiating spermatogonia into spermatocytes was determined in five Chinese hamsters. Large differences of up to a factor 2 were found between the numbers of A1 spermatogonia in the various animals. However, the numbers of leptotene spermatocytes varied only by up to a factor 1.2 between animals. It is concluded that more spermatogonial degeneration takes place in animals with a relatively large number of A1 spermatogonia than in those with a small number of these cells. In such a way in all animals ultimately about the same number of spermatocytes is formed.

An experiment was done in which the number of A1 spermatogonia was lowered with the S‐phase killer cytosine arabinoside (Ara‐C). It was found that this greatly increased the yield of the spermatogonial proliferation, showing a direct relationship between the number of A1 spermatogonia in an animal and the extent of the spermatogonial degeneration.

In addition to the variation in the number of A1 spermatogonia found between various animals, an even larger variation of up to a factor 3.7 was found between the numbers of A1 spermatogonia in different areas of seminiferous tubules within each animal. Nevertheless the variation in the number of leptotene spermatocytes in different areas within each animal was not larger than a factor 1.3. It is concluded that in the normal animal the phenomenon of spermatogonial degeneration depends on the local density of these spermatogonia. Apparently, when too many spermatogonia are present the surplus of cells degenerates.
Morphologic and histochemical analysis of the newt (Notophthalmus viridescens) liver
Authors: Goldblatt Peter J. , Hampton James A. , DiDio Lydia N. , Skeel Kristi A. , Klaunig James E.
Published: February 2005

Architectural arrangement, ultrastructure, and selected histochemical properties of the newt (Notophthalmus viridescens) liver were examined. Although hematopoietic tissue (1–4 cells thick) invested the liver, direct vascular communication between this tissue and hepatic parenchyma was not observed. The liver was intensely positive when stained with Oil‐red‐O and periodic acid‐Schiff reagent and connective tissue was limited to large vascular channels and the capsule. A distinctive polarity was observed in the hepatic vascular system when lobes were viewed in cross section. Dorsally, portal venules accompanied arterioles and branches of the biliary system, while tributaries of hepatic veins were observed ventrally. Following perfusion fixation, hepatocytes appeared as sheets of cells 1–5 cells thick; however, lobules as defined in adult mammalian liver were absent. Hepatocytes contained abundant smooth endoplasmic reticulum, mitochondria, electron‐dense lysosomes, patches of granular endoplasmic reticulum, and lipid droplets. Continuous endothelial cells lined sinusoids and exhibited fenestrae organized into structures similar to sieve plates observed in mammalian liver. Variable numbers of melanin‐containing macrophages and subendothelial macrophages were observed; however, Kupffer cells and lipid containing perisinusoidal fat‐storing cells were not seen. Patterns of reaction product for glucose‐6‐phosphatase (G‐6‐Pase), glucose‐6‐phosphate dehydrogenase (G‐6‐PDH), and succinic dehydrogenase (SDH) were localized in the newt liver. All enzymes exhibited a uniform distribution pattern; however, small punctate regions of intensely positive G‐6‐PDH cells were noted within hepatic parenchyma. Cells comprising the hematopoietic tissue were intensely positive for G‐6‐Pase, G‐6‐PHD, and negative for SDH.
Appearance of the cyst‐ or ductule‐like structures and their role in the restoration of the rat pituitary autograft
Authors: Gon Gotetsu , Shirasawa Nobuyuki , Ishikawa Hiroshi
Published: February 2005

The anterior pituitary glands of 31‐day‐old male rats were autotransplanted under renal capsule. At the 3rd and 5th day after transplantation, the autografts were observed by electron microscopy and by immunohistochemistry using antiserum against S‐100 protein, which serves as marker of folliculo‐stellate (FS) cells.

On the 3rd day, a large part of the graft was replaced with loose connective tissue in which the FS cells were remarkable in number. The FS cells encircled a small number of granular cells and formed cyst‐ or ductule‐like structures with neighboring FS cells. Together, FS cells and the encircled granular cells formed a basement membrane surrounding the entire ductule. Throughout the regenerating gland, many such ductules were found. On the 5th day, both granular cells and FS cells increased in number.

The above observations suggest that FS cells may play an important role in the restoration of degenerated pituitary glandular tissues during the early stage of the transplantation.
Distribution of actin in spermatids and adjacent sertoli cell regions of the rat
Authors: Masri B. A. , Russell L. D. , Vogl A. W.
Published: February 2005

In this study, we describe the distribution of actin filaments in and around spermatids that are mechanically dissociated, in the presence and absence of exogenous trypsin, from the seminiferous epithelium of the rat. NBD‐phallacidin and subfragment 1 of the myosin molecule (S‐1) are used as probes for filamentous actin at the light and electron microscopic levels, respectively.

The fluorescence associated with spermatids mechanically dissociated in the absence of trypsin is due to actin both in the spermatogenic cells themselves and in attached Sertoli cell ectoplasmic specializations. Fluorescence generated by labelled actin in ectoplasmic specializations occurs in linear tracts that follow the outer contour of spermatid heads. The residual flourescence seen when trypsin is used to detach Sertoli cell fragments is diffuse and due to f‐actin in the subacrosomal space. Electron microscopic data agree with the fluorescence results.

This study conclusively demonstrates that Sertoli cell ectoplasmic specializations remain attached to spermatids mechanically dissociated from the seminiferous epithelium. This observation may be useful when attempting to isolate ectoplasmic specializations for biochemical analyses.
Neovascularization in the pre‐ and postnatal rabbit corpora cavernosa penis: Light and electron microscopy and autoradiography
Authors: Fujimoto Sunao , Yamamoto Koji , Kagawa Hirohiko , Yoshizuka Mitsuaki , Nomiyama Tomohiko , Maruyama Takeshi
Published: February 2005

In the late prenatal stage, the rabbit corpora cavernosa penis (cavernous bodies) are occupied by a large number of mesenchymal cells actively proliferating by mitosis. Most profiles of the cavernous sinuses show growing capillaries consisting of immature endothelial cells and enclosing a narrow lumen. Such growing capillaries are often associated with the mesenchymal cells that contact with each other and eventually with the endothelial cells.

Between 1 and 7 postnatal days, the capillary network develops extensively and the maturation of the capillaries results in a flattened endothelium with a continuous basal lamina. The mesenchymal cells are also associated with the helicine arterial sprouts at this time period. No endothelial mitotic figures were observed within the growing capillaries in pre‐ and postnatal specimens examined.

Single pulse labeling with 3H‐thymidine in the postnatal rabbits demonstrates that the labeled endothelial cells of the growing capillaries increase in number at 48 hours after injection compared with those at 24 hours, whereas the labeled mesenchymal cells inversely decrease in number.

These findings indicate that the incorporation of the mesenchymal cells as vesselforming cells into the growing capillaries accelerates the neovascularization in the rabbit cavernous bodies.
The elasmobranch renal corpuscle: Fine structure of Bowman's capsule and the glomerular capillary wall
Authors: Lacy Eric R. , Castellucci Mario , Reale Enrico
Published: February 2005

The fine structure of the renal corpuscle of the marine elasmobranch fish, the little skate (Raja erinacea), and two species of dogfish sharks, the spiny dogfish (Squalus acanthias) and the smooth dogfish (Mustelus canis), was studied by light microscopy and by transmission (thin sections, freeze‐fracture replicas) and scanning electron microscopy. Bowman's capsule was lined by ciliated cells, similar to those of the first part of the tubule, at the urinary pole and squamous cells in the zone between urinary and vascular poles. At the vascular pole the visceral epithelial cells had some closely apposed cuboidal cell bodies with a few processes inserted along the basement membrane, but foot processes were absent. These cuboidal cells were continuous with podocytes, which had primary, secondary and tertiary processes from which the pedicels arose. An inconsistently present slit membrane bridged the pedicels at varying distance from the urinary space. Small maculae and large fasciae occludentes joined the podocytes and/or their processes among which gap junctions were observed. In the skate kidney, the podocyte plasma membrane facing the basement membrane contained orthogonal arrays of particles. The epithelial basement membrane of the glomeruli in all elasmobranchs was consistently thick. The mesangial cells were numerous and partially enveloped in a basement membrane; their long processes almost compeletely circumscribed the capillary walls. The mesangial matrix was abundant and consisted of loosely arranged collagen fibrils, microfibrils and occasional anchoring fibrils. The endothelial cells had irregularly distributed fenestrations of various sizes and lay on their discontinuous basement membrane which was separate from that under the epithelial cells. The filtration apparatus resembles that of immature mammals and lower vertebrates.
Unusual example of a persistent stapedial artery in a human
Authors: Diamond Michael K.
Published: February 2005

A complete dissection of a persistent stapedial artery and its companion venous sinuses revealed several noteworthy features. 1) The proximal portion of the stapedial artery stem was missing, and the entire stapedial system was supplied through an anastomosis between the occipital artery and the ramus posterior of the stapedial artery; a similar type of collateral supply occurs in some xenarthrans and bats. The ramus posterior is a component of the primitive eutherian stapedial system and one that has not been reported previously in a primate. 2) Both the anterior and posterior divisions of the ramus superior were present. The posterior division is identified here for the first time in a primate. 3) The anterior and posterior divisions were accompanied by the cranio‐obital and petrosquamous sinuses, respectively. These sinuses were incomplete and attenuated relative to the primitive eutherian condition.
Endocytosis and vesicular traffic in fetal and adult colonic goblet cells
Authors: Colony Pamela C. , Specian Robert D.
Published: February 2005

Structural and functional differences between adult and fetal colonic goblet cells have not been clearly defined. To compare the binding, uptake, and intracellular pathway of internalized apical membrane in fetal and adult goblet cells, cationic ferritin (CF) was used as a nonspecific probe. The initial distribution of membrane anionic sites was determined in segments of proximal and distal colon from fetal (18–22 days) and adult rats that were fixed prior to a 10‐minute exposure to CF at 4°C. Uniform binding along the apical membrane and microvilli was noted at all ages. To assess uptake and intracellular transport, segments of proximal and distal colon from fetal and adult rats were exposed to CF for 10 minutes at 4°C prior to a saline wash and incubation in saline or Liebovitz L‐15 medium for 3, 6, 15, 30, or 60 minutes at 37°C. In addition, fetal rats between 18 and 22 days gestation (birth) were exposed to CF continuously for 10–30 minutes via an intracaecal injection. The results showed extensive uptake of CF in the fetal goblet cells and a more variable intracellular pathway than in with the adult. Within 3 minutes, numerous CF positive vesicles and tubules were present within the apical cytoplasm as well as interspersed among the secretory granules of the fetal goblet cell. Most of these vesicles were smooth surfaced, although some were coated. By 15 minutes, CF was frequently seen in multivesicular bodies, and occasionally in vacuoles in the vicinity of the Golgi. No CF was detected in Golgi cisternae. In contrast to fetal cells, only limited uptake was noted in adult goblet cells and the vesicles were restricted to the periphery of the secretory granule mass. In addition, transport to lysosomes was the exclusive route of these vesicles in the adult. These findings indicate that vesicular uptake is extensive in fetal goblet cells and the intracellular pathway is more variable and less restricted than in the adult.
Electron microscopic immunostaining of nerve growth factor: Secretagogue stimulated submandibular glands
Authors: Hazen‐Martin Debra J. , Simson J. A. V.
Published: February 2005

Immunocytochemical localization of nerve growth factor (NGF) was assessed on thin sections of plastic‐embedded male mouse submandibular glands by electron microscopy. Both control and secretagogue‐stimulated glands were examined. NGF was localized in granules of both granular convoluted tubule (GCT) cells and transition cells. The latter were intermediate in morphology between GCT cells and striated duct cells. Both large and small granules were immunostained in GCT cells; however, considerable variability in immunostaining intensity was observed in both sizes of granules but especially in the small granules of transition cells. Rough endoplasmic reticulum (RER) in both cell types exhibited NGF immunoreactivity. No Golgi‐associated immunostaining was observed.

Following α‐adrenergic stimulation with phenylephrine, NGF‐containing granules were sharply reduced because of extensive degranulation. Pools of immunostained secretory material suggested intracellular fusion of NGF‐containing granules. Immunostaining was also observed on membrane fragments found within large vacuoles in GCT cells. Evidence of NGF secretion after β‐adrenergic or cholinergic stimulation was less dramatic. In isoproterenol‐stimulated GCT cells there was evidence of fusion of small, apical, NGF‐stained granules. These cells also possessed heavily immunostained apical membrane blebs. Pilocarpine‐stimulated cells exhibited pleomorphic immunostained apical granules but less apical membrane immunostaining. Abundant basal lysosomes appearing in GCT cells after pilocarpine stimulation did not stain for NGF.
The equine colonic mucosal granular cell: Identification and X‐ray microanalysis of apical granules and nuclear bodies
Authors: Pfeiffer Carl J. , Murray Michael J. , Fainter Lily
Published: February 2005

The granular columnar epithelial cell of the equine dorsal large colon has been studied by transmission electron microscopy and X‐ray microanalysis. Particular attention was focused on nuclear bodies commonly observed as central clusters of spherical, electron‐dense inclusions within the nucleus. Ultrastructural morphology as well as X‐ray microanalysis spectra reveal great similarity between colonic nuclear bodies and the numerous small granules of the apical cytoplasm in these epithelial cells. X‐ray spectra of these cells were distinct from those of goblet cell mucous granules and mast cell granules. No evidence was found indicating transit of nuclear body granules through the nuclear envelope, or for morphologic association with the nucleoli. Of the diverse types of nuclear bodies previously reported in other species, equine colon nuclear bodies morphologically most closely resemble those seen in rabbit adenohypophysis. Colon epithelial cell nuclear bodies are likely identical to equine small intestine nuclear bodies, but their origin and role remain unknown.
Further observations on the sympathetic pathways to the pupil
Authors: Parkinson Dwight
Published: February 2005

The clinical disturbance resulting from section of the sympathetic in the neck; miosis, decreased sweating, increased vascularity and narrowing of the palpebral fissure is universally recognized while the definitive sympathetic pathways remain unknown. Most current texts depict a plexus along the surface of the parasellar carotid as part of that pathway although a previous review leaves the large connection of the carotid sympathetic to the sixth and then to the first division of the fifth cranial nerve as a putative pathway. Recent reports of complete tears of the parasellar carotid without sympathetic changes tend to further discount a carotid plexus as a pathway and focus attention on the direct carotid sympathetic nerve connections to the sixth and fifth cranial nerves as probable but unproven pathways, the interruption of which, result in Bernard, Mitchell, Horner Syndrome. (Parkinson '79).
Development of the notochord in human embryos: Ultrastructural, histochemical, and immunohistochemical studies
Authors: Shinohara Haruo , Tanaka Osamu
Published: February 2005

In the present study of the notochord, the specimens were 54 externally‐normal human embryos ranging between Carnegie stages 13 and 23. The following staining procedures were used: periodic acid‐Schiff (PAS), modified method of PAS, alcian blue, colloidal iron, and toluidine blue. Routine electron microscopic techniques were used. Immunoreactivity of the notochord to α‐enolase was also examined. The notochord cells were undifferentiated in stage 13 with few intracellular organelles. The microfibrils and deposition of acid mucopolysaccharides appeared in the notochordal sheath in stage 14. The characteristic relation of mitochondria with rough endoplasmic reticulum was observed. Golgi complexes increased in the perinuclear region in stage 15. The layer of microfibrils in the notochordal sheath initially separated from the notochord in stage 16. Glycogen, mucoprotein, neutral mucopolysaccharides, and glycolipids began to increase in the mesenchymal cells around the notochord, starting at stage 16. Acid mucopolysaccharides increased in the notochordal sheath and in the matrix of the precartilage area around the notochord as this embryonic stage advanced. It was also revealed that the immunoreactivity of the notochord to α‐enolase remained constant during the embryonic period. The results show that the notochord is transformed from an apparently undifferentiated organ into an organ with secretory activity in stage 14, producing microfibrils and depositing acid mucoplysaccharides in the notochordal sheath. The immunoreactivity of the notochord to α‐ and γ‐enolase isoenzymes and the development of the notochord are discussed. This study was undertaken to provide additional information on the development of tumors of notochordal origin.
Effects of unilateral ovariectomy before and after mating on fetal and placental growth in rats
Authors: Rahima Ali , Bruce Neville W.
Published: February 2005

Unilateral ovariectomy was carried out on rats either 8 days after mating (ULO‐A) or 4–6 weeks before mating (ULO‐B) and the effects on fetal and placental weights were examined at days 13, 16, and 22 of gestation. ULO‐A caused initial fetal and placental hypotrophy at day 13, but thereafter placental weights increased to 123% and 132% of control values at days 16 and 22, respectively. Fetal weights were also 9% heavier in the ULO‐A rats at day 22. The ULO‐B stimulus resulted in placental but not fetal hypotrophy at day 13 and placental hypertrophy at days 16 and 22. Although the results of the two stimuli were generally similar, it is argued that the mechanisms underlying the ULO‐A results were primarily endocrinological whereas those for the ULO‐B results were due to crowding of conceptuses in one uterine horn and the subsequent compensatory responses.
Membrane domains in guinea pig sperm and their role in the membrane fusion events of the acrosome reaction
Authors: Flaherty Sean P. , Olson Gary E.
Published: February 2005

In this study, we have examined the structure of domains of the periacrosomal plasma membrane (PM) and outer acrosomal membrane (OAM) of guinea pig sperm and defined their fate during the membrane fusion events of the acrosome reaction. Cauda epididymal sperm were arranged in rouleaux, joined by periacrosomal PM “junctional” zones; in these zones, the PMs were linked by cross bridges formed from a paracrystalline glycocalyx. Bridging elements linked the PM to the OAM on the ventral (concave) but not dorsal (convex) aspect of the apical segment. Parallel filaments were associated with the luminal face of the OAM overlying the dorsal surface of the apical segment. Sperm were induced to undergo a “synchronous” acrosome reaction after preincubation in Ca2+‐free medium containing lysolecithin, by the addition of Ca2+. Fusion between the OAM and PM occurred at the boundaries but not within the PM “junctional” zones over the apical segment. In nonjunctional regions on the dorsal surface of the apical segment, sheets of unfenestrated hybrid membranes and parallel arrays of hybrid membrane tubules formed, while branching arrays of hybrid membrane tubules and vesicles were observed on the ventral surface. In the principal segment, networks of branching hybrid membrane tubules initially formed but later transformed into vesicles. Hence, the lysolecithin‐mediated guinea pig sperm acrosome reaction involves a complex sequence of membrane fusions, which differs in domains of the periacrosomal PM and OAM. Stable nonfusigenic domains are present in both the PM and OAM of the apical segment; membrane‐associated assemblies may maintain these domains and may also provide direction to some of the membrane fusion events of the acrosome reaction.
Androgen receptor‐deficient Tfm cells in the mosaic epididymis of sex‐reversed mice heterozygous for Tfm: An autoradiographic study with [3H]‐dihydrotestosterone and [3H]‐estradiol
Authors: Drews Ulrich , Schleicher Gunter , Stumpf Walter E. , Thiedemann Klaus‐Ulrich
Published: February 2005

Testicular feminization (Tfm) in the mouse is characterized by androgen insensitivity of the target cells. We describe the presence of androgen‐insensitive Tfm cells in the epididymis of mosaic mice produced by converting female carriers of the Tfm mutation (XTfm/X+) to males via the sex reversal factor (Sxr). The mosaic arises by random X‐inactivation. In the epididymal duct, flat undifferentiated Tfm cells are interspersed between high columnar wild‐type cells.

By thaw‐mount autoradiography we show that after injection of [3H]dihydrotestosterone, radioactivity is concentrated in the nuclei of high columnar wild‐type cells, whereas the nuclei of the low cuboid Tfm cells remain free of nuclear radioactivity. After injection of [3H]estradiol, both Tfm and wild‐type cells show nuclear labeling. Our observations demonstrate that Tfm cells in the mosaic epididymis selectively lack nuclear dihydrotestosterone‐binding sites, whereas estradiol‐binding sites are intact.