bluuebunny/crossref_metadata_2025 huggingface dataset:
Tetracycline administration restores osteoblast structure and function during experimental diabetes
Authors: Sasaki Takahisa , Kaneko Haruki , Ramamurthy Nungavaram S. , Golub Lorne M.
Published: February 2005

Osteopenia is a recognized complication of diabetes mellitus in humans and experimental animals. We recently found that tetracyclines prevent osteopenia in the streptozotocin‐induced diabetic rat and that this effect was associated with a restoration of defective osteoblast morphology (Golub et al., 1990). The present study extends these initial ultrastructural observations by assessing osteoblast function in the untreated and tetracycline‐treated diabetic rats. After a 3‐week protocol, non‐diabetic control and diabetic rats, including those orally administered a tetracycline, minocycline (MC), or a non‐antimicrobial tetracycline analog (CMT), were perfusion‐fixed with an aldehyde mixture; the humeri were dissected and processed for ultracytochemical localization of alkaline phosphatase (ALPase) and Ca‐ATPase activities. Some rats from each experimental group received an intravenous injection of 3H‐proline as a radioprecursor of procollagen, and the humeri were processed for light microscopic autoradiography. In addition, the osteoid volume in each experimental group was quantitatively examined by morphometric analysis of electron micrographs.

During the diabetic state, active cuboidal osteoblasts in the endosteum of control rats were replaced by flattened bone‐lining cells that contained few cytoplasmic organelles for protein synthesis (Golgi‐RER system), and active transport (mitochondria). Treating diabetic rats with MC, and even more so with CMT, appeared to “restore” osteoblast structure. During diabetes, bone‐lining cells incorporated little 3H‐proline or secreted little labeled protein and produced only a very thin osteoid layer. Tetracycline administration to the diabetics increased both the incorporation of 3H‐proline by osteoblasts and their secretion of labeled protein toward the osteoid matrix, in a pattern similar to that seen in the non‐diabetic controls. Intense alkaline phosphatase (ALPase) activity was cytochemically demonstrated along the plasma membranes of osteoblasts in the non‐diabetic control rats, but was completely absent from the bone‐lining cells in the diabetics. Similar to that described above, CMT therapy restored the ALPase activity in the diabetic osteoblasts and the effect of MC was less dramatic. The distribution and intensity of Ca‐ATPase in the osteoblast‐plasma membranes of the different groups of rats were similar to that of ALPase, except for the absence of detectable Ca‐ATPase in the MC‐treated diabetics. These results suggest that diabetes‐induced osteopenia reflects, al least in part, impaired osteoblast structure and function and that tetracyclines, by a non‐antimicrobial mechanism, may prevent this bone deficiency by normalizing these bone‐lining cells.
Evidence that vinculin is co‐distributed with actin bundles in ectoplasmic (“junctional”) specializations of mammalian sertoli cells
Authors: Pfeiffer David C. , Wayne A.
Published: February 2005

Ectoplasmic specializations of Sertoli cells are actin containing structures found at sites of attachment to spermatids and to neighboring Sertoli cells. We suspect that these cytoskeletal structures are a form of actin‐associated adhesion junction. If this is true, then molecular components, such as vinculin, that characterize actin‐associated adhesion junctions in general should be present in ectoplasmic specializations.

In this paper we have used two approaches to verify the prediction that vinculin is a component of ectoplasmic specializations. First, we have used fluorescence microscopy to probe immunologically for vinculin in ectoplasmic specializations associated with spermatids of the ground squirrel. Second, we have used immunogold techniques to probe for vinculin in ectoplasmic specializations of rat testis.

Our results indicate that the immunological probe for vinculin was reactive with ectoplasmic specializations. In single label fluorescence experiments, linear patterns obtained with the vinculin probe were similar to those obtained with probes for filamentous actin. In double label experiments, the vinculin probe was codistributed with the actin probes. In immunogold studies, specific labelling with the probe for vinculin occurred in ectoplasmic specializations both at sites of attachment to spermatids and adjacent to basal Sertoli cell junctions. Moreover, gold particles were concentrated adjacent to filament bundles within each ectoplasmic specialization.

Our results support the conclusion that vinculin is present in ectoplasmic specializations. Further, they indicate that vinculin is co‐distributed with actin bundles within each ectoplasmic specialization.
Immunocytochemical localization of follicle regulatory‐protein (FRP) in testis
Authors: Ahmad Nazir , Pringle Jean , Toppari Jorma , Tonetta Sharon A. , Dizerega Gere S.
Published: February 2005

Follicle regulatory protein (FRP) can exert paracrine control over follicular development. It is synthesized by the granulosa cells of the developing follicles and was localized in the cytoplasm of the mural cells by immunocytochemistry. When administered to male dogs and rats, FRP causes impairment of spermatogenesis. In the intact male rat, it has been postulated that FRP manifests its effects at a stage prior to the conversion of testosterone to dihydrotestosterone. Sertoli cells of the seminiferous tubules are implicated in testosterone metabolism. Furthermore, Sertoli cells in male gonads are regarded as the counterpart of granulosa cells in ovaries. The exact source of FRP in the male is not known. Therefore, it was of interest to study the localization of FRP in the male gonads. Testicular sections of the pig, dog, cat, rat, mouse, monkey, and man were immunocytochemically stained with monoclonal antibody to porcine FRP of ovarian origin. Sections of pig ovaries were used as controls throughout the study. Specificity of immunocytochemical localization was established by preabsorption. FRP antibody predominantly localized to the interstitial compartment of the pig testis. In the seminiferous tubules, FRP localization was limited to basal spermatogonia and Sertoli cells of tubules at few specific stages of spermatogenesis. The study also showed that the monoclonal antibody against porcine FRP is species‐specific. Antibody binding was found only in pig testis, whereas tissues from the cat, dog, mouse, rat, monkey, and man did not display any immunocytochemical reaction. Since in the pig testis, Sertoli cells at specific stages of spermatogenesis showed FRP localization, it would appear that FRP production is not being carried out by Sertoli cells at other stages. Due to the fact that all of the interstitial cells stained with FRP and some of the Sertoli cells were stained with FRP‐antibody, it is not possible to ascertain the exact cell type responsible for FRP synthesis and secretion in testis using immunocytochemistry. Since the antibody to FRP of ovarian follicular fluid origin bound to various testicular cells, it would appear that FRP or a protein of similar nature may also be present in the testes.
Solitary neuroendocrine cells and neuroepithelial bodies in the lower airways of embryonic, fetal, and postnatal sheep
Authors: Balaguer Luis , Romano Jacinta
Published: February 2005

The sheep pulmonary intraepithelial APUD system was studied by histochemical, immunocytochemical, and electron microscopy techniques during different periods of lung development: embryonic, fetal (pseudoglandular, canalicular, and alveolar), and postnatal.

The cells of the ovine pulmonary intraepithelial APUD system were found randomly distributed throughout the conducting and respiratory or undifferentiated airways. They appeared as isolated cells (solitary neuroendocrine cells) or in groups (neuroepithelial bodies).

These cells were argyrophilic and immunoreactive for neuron‐specific enolase but were not argentaffin. Ultrastructurally they were characterized by a basal position in the respiratory epithelium and by the presence of neurosecretory granules (dense‐core vesicles) ranging between 65 and 230 nm of diametre.

Quantitative studies showed that single neuroendocrine cells were more numerous in distal conducting airways and at fetal stages.

The earliest identifiable argyrophilic and NSE‐immunoreactive neuroendocrine cells in sheep airways appeared at gestational week 5, close to the term of the embryonic period.
Mechanoreceptors of the hard palate of the mongolian gerbil include special junctions between epithelia and meissner lamellar cells: A comparison with other rodents
Authors: Tachibana Tamiko , Fujiwara Naoki , Nawa Tokio
Published: February 2005

As a part of our comparative morphological study of mechanoreceptors in rodent oral mucosae, the hard palate of the mongolian gerbil (a kind of sand rat) was investigated by light and electron microscopy. Subepithelial connective tissue papillae of palatine rugae contained a dense distribution of lamellated corpuscles that showed an ultrastructure similar to that of Meissner corpuscles of primates. The corpuscles in the palate of the mongolian gerbil, however, frequently formed compound large corpuscles with a palisade‐like extension. Antemolar rugae predominated in containing such compound “Meissner” corpuscles. Superficial cytoplasmic lamellae of the corpuscles closely adhered to overlying epithelial cells without an intervening basal lamina. Although a small number of simple corpuscles was seen in the first antemolar ruga, no similar corpuscles were encountered in other parts of the palate. On the other hand, numerous Merkel cellnerve endings were seen in epithelial pegs and sometimes in epithelial ridges of palatine rugae. Quinacrine labelling showed that intermolar rugae contained a rather dense distribution of Merkel cells in comparison with antemolar rugae. The present and previous data indicate that the pattern of palatine mechanoreceptors of the mongolian gerbil is analogous to that of the mouse, but not of the rat.
Numbers and proportions of unmyelinated axons at cervical levels in the fasciculus gracilis of monkey and cat
Authors: Garrett Lizabeth , Coggeshall Richard E. , Patterson Joel T. , Chung Kyungsoon
Published: February 2005

The present study is a quantitative analysis of the unmyelinated fiber population in the fasciculus gracilis of the second cervical segment of cat and monkey. We find that unmyelinated fibers represent 13.7% of the total fiber population in this pathway in the cat and 18.9% in the monkey (Macaca fascicularis). The existence of such large numbers of these axons suggests that there may be a sizeable ascending fine primary afferent pathway in the fasciculus gracilis in cat and monkey whose destination is presumably the dorsal column nuclei. These findings are of interest in regard to classic ideas that the afferent fibers in the dorsal columns are large myelinated fibers that convey fine discriminative information to the dorsal column nuclei.
Morphometry and histoenzymology of the hamster tenuissimus and its muscle spindles
Authors: Patten Robert M. , Ovalle William K.
Published: February 2005

Muscle spindles and extrafusal fibers in the tenuissimus muscle of mature golden Syrian hamsters were studied morphologically and quantitatively using several light microscopic techniques. Muscle spindles were identified in serial‐transvere frozen‐sections of whole muscles stained with hematoxylin and eosin. Five tenuissimus muscles were examined from origin to insertion, and the locations of individual receptors were plotted in camera‐lucida reconstructions. Spindles were found in proximity to the main neurovascular bundle in the central core of each muscle. A range of 16–20 receptors was noted per muscle. The mean muscle spindle index (the total number of spindles per gram of muscle weight) was 503 and the average spindle length was 7.5 mm. Oxidative enzyme and myosin adenosine‐triphosphatase (ATPase) staining profiles were also evaluated in the intrafusal and extrafusal fibers in each muscle. Even numbers of type I and type IIA extrafusal fibers were distributed homogeneously throughout all muscle cross‐sections. Histochemical staining patterns varied along the lengths of the three intrafusal fiber types. Nuclear chain fibers possessed staining properties similar to the type IIA extrafusal fibers and exhibited no regional variations. Bag1 fibers displayed staining variability, particularly when treated for myosin ATPase under acid preincubation conditions. Some spindles were isolated under darkfield illumination and then either treated with 7‐nitrobenz‐2‐oxa‐1, 3‐diazole (NBD)‐phallacidin to detect filamentous actin by fluorescence microscopy, or prepared for conventional scanning electron microscopy (SEM). By fluorescence microscopy, a registered actin banding‐pattern was observed in the sarcomeres of the intrafusal fibers, and variations in the intensity of banding were noted amongst different fibers. SEM revealed punctaie sensory nerve endings that adhered intimately to the surfaces of underlying intrafusal fibers in the equatorial and juxtaequatorial regions. By transmission electron microscopy (TEM) these endings appeared crescent‐shaped and were enveloped by external laminae. Each profile contained numerous mitochondria and cytoskeletal organelles. The high spindle density observed in this muscle suggests that the hamster tenuissimus may function in hindlimb proprioception.
The differentiation of the skin and its appendages. I. Normal development of papillary ridges
Authors: Morohunfola Kehinde A. , Jones Terrel E. , Munger Bryce L.
Published: February 2005

In the present study, the normal development of papillary ridges was studied in the volar pads of both fore and hindpaws of the opossum, Monodelphis domesticus. At birth, the developmental state of the opossum's paws is equivalent to that of a six‐week human embryo. The development of papillary ridges in the opossum occurs entirely postnatally and the hindpaw lags behind the forepaw by at least four days in most developmental parameters. Papillary ridge formation is preceded by four events: skin innervation, Merkel cell differentiation, mesenchymal condensation, and epidermal proliferation. The apical pads at the tips of the digits and the interdigital pads between the heads of the metacarpals (or metatarsals) have a unique pattern of innervation and mesenchymal content as compared to the non‐pad skin. Each pad is innervated by a prominent nerve trunk and axons ascend towards the epidermis providing a density of innervation that exceeds that in the non‐pad epidermis. Merkel cells are absent in non‐pad epidermis but present in the pads prior to the onset of formation of papillary ridges. A loose aggregation of mesenchyme forms the core of the pads and the superficial dermis is more cellular in the pads as compared to the equivalent dermis in surrounding non‐pad skin. Developing papillary ridges always contained Merkel cell‐axon complexes.

Merkel cell axon complexes serve as the anatomical substrate of slowly adapting (SA) mechanoreceptors. The presence of these complexes during early skin differentiation is consistent with the use of the opossum's forepaw in climbing to the nipple, but also suggests other possible functions. We hypothesize that the nervous system might play a role in the timing or patterning of the formation of papillary ridges.
Interspecies comparison of cellular localization of the cyanide metabolizing enzyme rhodanese within olfactory mucosa
Authors: Lewis J. L. , Rhoades C. E. , Bice D. E. , Harkema J. R. , Hotchkiss J. A. , Sylvester D. M. , Dahl A. R.
Published: February 2005

The observation of high levels of xenobiotic metabolizing enzyme activity in the olfactory mucosa has produced speculation on the functional significance of these enzymes in the nose. Hypothesized roles include protection of the nasal epithelium, lung, and other downstream tissues, and termination or modification of olfactory responses. The enzyme rhodanese metabolizes cyanide, which is a commonly inhaled toxicant and an odorant and therefore of interest to both toxicologists and olfactory neurobiologists. The cellular localization of this enzyme within the olfactory mucosa will have important consequences for its ability to protect specific cells, as well as its ability to alter the concentration of inhaled cyanide at receptors, and therefore could provide clues as to its function in this tissue. We have compared the distribution of this enzyme in two species, the rat and the cow, using immunohistochemical localization techniques employing species‐specific polyclonal antisera raised in our laboratory. In the rat, rhodanese‐like immunoreactivity was greatest within the apical portion of the sustentacular cells, the basal cells, and the duct cells of Bowman's glands. Very little to no reaction was observed in the acinar cells of Bowman's glands. In the cow, however, the acinar cells and duct cells of Bowman's glands showed intense immunoreactivity with little to no reaction observed in the sustentacular or basal cells. The differences in localization of rhodanese in these two species may have important implications for cell types at risk during inhalation of cyanide or organonitrile compounds metabolized to cyanide within the nasal mucosa. In addition, the difference in distribution in the two species emphasizes the importance of considering enzyme activity and localization in the determination of an appropriate animal model for study of both nasal toxicology and olfactory responsiveness in humans.
Immunocytochemistry of paraneurons in the female urethra of the horse, cattle, sheep, and pig
Authors: Vittoria Alfredo , Cocca Tiziana , La Mura Elena , Cecio Aldo
Published: February 2005

The aim of this study is to describe the presence of neuroendocrine (NE) cells (paraneurons), producing biogenic amines and/or peptidergic hormones, in the female urethra of cattle, sheep, pigs, and horses, by means of histochemical and double labeling immunofluorescent techniques. 5‐Hydroxytryptamine‐, chromogranin A‐, cholecystokinin‐ and somatostatin‐containing NE cells are present in the urethral epithelium of all the species studied, with the unique exception of the lack of somatostatin cells in the horse. Paraneurons containing 5‐hydroxytryptamine colocalized with chromogranin A or cholecytokinin were also found in all subjects. Such active substances are hypothesized to play a role in the contraction of the urethral musculature, emission of urogenital fluids, and inhibition of endocrine and exocrine secretions. © 1992 Wiley‐Liss, Inc.
Effect of growth on architecture of rat semimembranosus lateralis muscle
Authors: Willems Mark E. T. , Huijing Peter A.
Published: February 2005

Architecture of semimembranosus lateralis muscle (SMI), an almost parallel‐fibered muscle with bony origin and aponeurotic insertion of its muscle fibers, was studied in male Wistar rats of two age groups. Using photographic techniques and maximal stimulation active muscle architecture was determined at muscle optimum length. Muscle length increases were almost similar with fiber length increases (approximately 36%). Aponeurosis length increased (by 31%) as did angle of the aponeurosis with the line of pull (approximately 4°). Angles of the proximal as well as distal fibers with the line of pull were unchanged. Increases in mean fiber diameter were estimated to be approximately 50%. It is likely that increased mean fiber diameter was accommodated at the bony origin by enlargement of its area. At the aponeurosis increased mean fiber diameter was accommodated by increased length of the aponeurosis as well as a change in fiber angle with the aponeurosis. This change in fiber angle proved to be different in the proximal and distal part of the aponeurosis. Under the assumption of a uniform change in fiber diameters, a gradient of length change along the aponeurosis occurs. It is concluded that growth in an almost parallel‐fibered muscle with a bony attachment results in different architectural adaptations in the parts close to the bony attachment as compared to those close to the aponeurosis. This difference is due to the fact that adaptation of aponeurosis angle with the line of pull occurred, which was not the case for angle of the line of origin with the line of pull. © 1992 Wiley‐Liss, Inc.
Distribution of gonadotrophins within the anterior pituitary cells of the musk shrew (Suncus murinus L.)
Authors: Shiino Masataka , Hirano Naomi , Miyajima Masayasu
Published: February 2005

Gonadotrophs in the anterior pituitary gland of the musk shrew were first identified by means of electron microscopic immunocytochemistry. The gonadotrophs of the musk shrew revealed quite unusual ultrastructural features that have never been seen before in other species.

These cells contained two types of secretory granules, i.e., small dense, roundshape granules and large lucent, irregular‐shape granules. FSHβ and LHβ were mostly observed together on both small and large secretory granules. The distribution pattern of the subunits of gonadotrophs was slightly altered following gonadectomy in the musk shrew. © 1992 Wiley‐Liss, Inc.
Morphological observations supporting muscle fiber hyperplasia following weight‐lifting exercise in cats
Authors: Giddings C. J. , Gonyea W. J.
Published: February 2005

Although exercise‐induced muscle fiber hyperplasia has been demonstrated through direct fiber counts following nitric‐acid digestion of muscle, morphological studies to determine the mechanism of hyperplasia have not been performed previously. In this study, light and electron microscopy were used to evaluate evidence of muscle fiber splitting or de novo formation of new muscle fibers. Since both fiber hypertrophy and hyperplasia may result in alterations in the muscle nuclear populations, myonuclear number and satellite cell frequency were assessed quantitatively to determine their role in regulating muscle fiber size. Ten adult cats performed weight‐lifting exercise, and the right (exercised) and left (control) forelimbs were fixed by vascular perfusion. Spaced serial sections were used to evaluate muscle fiber morphology along the lenght of fibers, and muscle fiber areas were measured. Myonuclei and satellite cells were counted using electron microscopy. Morphological evidence supporting muscle fiber hyperplasia was observed in exercised muscles. These observations included the presence of small fibers which may signify de novo fiber formation. Myonuclear counts indicate that myonuclear density is not a primary regulator of fiber size. Satellite cell frequency was unchanged following exercise. Autoradiographic studies revealed satellite cell activation by uptake of tritiated thymidine in exercised muscles. Satellite cell activation appears to result from increased activity in exercised muscles. These findings confirm previous studies demonstrating muscle fiber hyperplasia following weight‐lifting exercise, and suggest that de novo fiber formation is the major mechanism contributing to muscle fiber hyperplasia in this model. © 1992 Wiley‐Liss, Inc.
Partitioning of the Golgi apparatus in rat primary and secondary spermatocytes during meiosis
Authors: Oke B. O. , Suarez‐Quian C. A.
Published: February 2005

We examined the disassembly and reformation of the Golgi apparatus as a function of the cycle of the seminiferous epithelium in adult rats during stages XIII and XIV, i. e., just prior to and during meiosis I and II. Serial section analysis of primary spermatocytes at metaphase I demonstrated the presence of two Golgi complexes. At the ultrastructural level, these Golgi complexes were shown to be composed of stacks of cisternae and vesicles, with each stack having a varying number of saccules. Although Golgi complex intermediates resulting from the process of organelle disassembly were not clearly identified in diplotene spermatocytes immediately prior to nuclear envelope vesiculation, we did observe clusters of vesicles resembling the “nuage,” with each cluster varying in size and number of vesicles. Meoisis I results in the formation of secondary spermatocytes that exhibit a well‐formed spherical Golgi complex approximately half the size of the diplotene spermatocyte Golgi. Next, secondary spermatocytes enter meiosis II. In contrast to metaphase I, during metaphase II reformation of the Golgi apparatus into stacks was not observed and only small clusters of vesicles at two poles of dividing cells were detected. In addition, “nuage”‐like structures were not identified during meiosis II.

Our results begin to characterize the process by which Golgi apparatus partitioning is accomplished during meiosis, presumably resulting in the delivery of equal complements of this organelle to four round spermatids. We suggest that partitioning of the Golgi apparatus takes place prior to metaphase I and that the two steps of meiosis may exhibit subtle differences with respect to Golgi partitioning. © 1992 Wiley‐Liss, Inc.
A new look at the blood supply of the retro‐ocular space three‐dimensional analysis of the arterial pattern of the posterior ciliary artery
Authors: Yoshii Itaru , Ikeda Akira
Published: February 2005

A study of the arterial architecture of the orbit, especially the ophthalmic artery and the course of the posterior ciliary artery in the retroocular space, was carried out in 198 cadavers by three‐dimensional arteriographic analysis. The posterior ciliary arteries were classified into three types: lateral posterior ciliary, medial posterior ciliary, and accessory posterior ciliary arteries. Both the lateral and medial posterior ciliary arteries reach the eyeball in three ways: (1) they run antero‐inferiorly in a winding course to the posterior margin of the eyeball, then shift upward vertically at a 60–90 degree angle and reach the eyeball, where they divide into several ciliary branches (69%); (2) after a similar course, others branch to the eyeball from the superior side (29.3%); or (3) they reach the eyeball in an almost straight course along the optic nerve (1.7%). The fundamental characteristics of these three types of posterior ciliary artery pattern also exist in subhuman primates. © 1992 Wiley‐Liss, Inc.
Anatomical studies of the coronary system in elasmobranchs: II. Coronary arteries in hexanchoid, squaloid, and carcharhinoid sharks
Authors: De Andrés A. V. , Muñoz‐Chápuli R. , Sans‐Coma V. , García‐Garrido L.
Published: February 2005

Coronary artery anatomy was studied in 16 shark species belonging to 9 families of the orders Hexanchiformes, Squaliformes, and Carcharhiniformes. The study included 101 specimens and used an injection‐corrosion technique that obtained internal casts of the main trunks and coronary arterial branches.

The results showed 2 main patterns of coronary arterial arrangement: the dorsoventral coronary trunk pattern, shared by lamnoid and advanced carcharhinoid sharks, and the lateral coronary trunk pattern, shown by hexanchoid and squaloid sharks. Scyliorhinus and Galeus had intermediate arrangements of their vessels. © 1992 Wiley‐Liss, Inc.
A novel, [tyrosyl‐3,5‐3H]oxytocin binding, uterine cell population in the rat
Authors: Guldenaar S. E. F. , Nicholson H. D. , McCabe J. T.
Published: February 2005

The cellular localization of uterine oxytocin binding sites in the rat was studied by means of in vitro receptor autoradiography. Using [tyrosyl‐3,5‐3H]oxytocin as ligand, binding sites were localized in tissue sections from uteri of estrous, mated, and artificially cervically stimulated rats (n = 4 per group), and specificity of binding was investigated by means of simultaneous incubations with oxytocin, [Gly4, Thr7]oxytocin and [Arg]vasopressin. A previously unidentified type of cell was densely labelled by tritiated oxytocin. The labelled cells were preferentially localized near the endomyometrial border and at the interface of the circular and longitudinal muscle layers. In addition, these cells were found in the muscle layers. The dense labelling of these cells, which did not constitute part of the endometrial epithelium or blood vessels, was abolished when oxytocin or [Arg]vasopressin, but not [Gly4, Thr7]oxytocin, was added to the incubation medium. Binding of the radioligand was also found on muscle cells of the circular and longitudinal layers of the myometrium and cells of the endometrial luminal and glandular epithelium. Whereas incubation with oxytocin and [Gly4, Thr7]oxytocin diminished the labelling in both myometrium and endometrium, incubation with [Arg]vasopressin reduced labelling only in the myometrium. Similar results were obtained in tissues from rats in different reproductive states. This study demonstrates the presence of oxytocin binding sites in three different types of cell in the uterus of the rat. While the sites in the myometrium may be associated with the contractile response of this type of tissue to oxytocin, the functional significance of oxytocin binding sites on the endometrial epithelium and in the densely labelled, scattered cell remains to be elucidated. © 1992 Wiley‐Liss, Inc.
Immunohistological characterization of proximal colonic lymphoid tissue in the rat
Authors: De Boer Nynke K. , Kroese Frans G. M. , Sharp J. Graham , Perry Greg A.
Published: February 2005

Proximal colonic lymphoid tissue (PCLT) is a lymphoid structure located in the proximal colon of the mouse and the rat. In the present investigation we studied the immunomorphology and cytology of PCLT in the rat. We also studied sites of lymphocyte proliferation using the BrdU‐anti BrdU technique.

Results demonstrated no evident phenotypical differences between the lymphocyte populations of PCLT and either jejunal or ileal Peyer's patches (PP). The majority of the lymphocytes within PCLT were B cells localized in follicles, which were separated from each other by interfollicular T cell areas. Germinal centers (GC), containing ED5+ follicular dendritic cells, are found within PCLT follicles. The T cell areas contained both MHC Class II+ interdigitating cells and high endothelial venules. Studies using BrdU‐anti BrdU indicated that lymphocyte proliferation within PCLT taken place mainly in germinal centers.

Together the data show that the organization, lymphoid constituents, and sites of lymphocyte production are very similar in PCLT and PP. We therefore conclude that PCLT in the rats is not a Bursa equivalent, but more likely a PP with some special characteristics. © 1992 Wiley‐Liss, Inc.
Arteriographic study of the rabbit lower limb
Authors: McNally M. A. , Small J. O. , Mollan R. A. B. , Wilson D. J.
Published: February 2005

The rabbit hind limb has been used extensively as an orthopaedic model in the investigation of fracture pathology and healing and the effects of vascular abnormalities. However, a detailed description of the normal arterial supply appears to be absent from the literature. A study of the entire arterial vasculature has been undertaken using a lead oxide injection technique developed for this and other orthopaedic studies. This technique has proved reliable and inexpensive, giving high‐quality arteriography, which is easily interpreted. Accurate description of the arterial anatomy is possible without the need for repeated dissection. The rabbit lower limb shows some interesting variations in blood supply, particularly below the knee. The foot has three distinct patterns of blood supply, depending on the presence or absence of the peroneal artery and the degree of dominance of the dorsalis pedis artery. This arrangement has not previously been described and differs from the situation in other mammals. The arteriographic technique and the anatomical description have allowed the interpretation of changes occurring in the vasculature after injury in a fracture model. © 1992 Wiley‐Liss, Inc.
Macrostructure differences of polar fox and dog lungs
Authors: Voyevoda T. V. , Shishkin G. S. , Valitskaya R. I. , Umantseva N. D.
Published: February 2005

The lungs of the polar fox and dog have the typical form and lobular structure characteristic of beasts of prey. Both display secondary fusion of the cranial and middle lobes in the left lung, but this is more extensive in the fox. A consistent relationship between the beast body mass and the mass and volume of the lungs is present. The relative weight of dog lungs independent of body size (weight index) is 1.7 times that of the polar fox. In the latter the parenchyma is much more subdivided than in the dog. There are 23 segments per lung pair in the polar fox, compared to 19 in the dog. Although these are of unequal size throughout the lungs of both species, corresponding segments in the fox are about half as large as those in the dog. The greater segmentation of polar fox lungs may be of assistance in restricting the spread of inflammatory processes. © 1992 Wiley‐Liss, Inc.
Fine structural characteristics of the zone of contact between the lower infundibular stem and the pituitary pars distalis in the little brown bat, myotis lucifugus
Authors: Anthony Edythe L. P. , Neel Kevin , Cicione Mary Elizabeth
Published: February 2005

The purpose of this study was to examine the morphological characteristics of the pituitary gland in the little brown bat that might influence mechanisms of hypothalamic releasing hormone transport. Paraffin sections were prepared from whole crania to examine in situ the orientations of the three parts of the adenohypophysis (pars distalis, pars intermedia, and pars tuberalis) relative to the components of the neurohypophysis (pars nervosa and infundibular stem) and the basal hypothalamus. Of particular interest was the observation that the axis of the infundibular stem is directed posteriorly from the median eminence and occupies a depression in the dorsal surface of the pars distalis as it approaches the pars nervosa. Previous studies have revealed that neuronal projections containing releasing hormones extend into the infundibular stem in this species. Therefore, we conducted a fine structural study to determine whether the zone of contact between the infundibular stem and the pars distalis could represent a site of specialized interaction between hypophysiotropic hormones and their target cells. The results show that the sparse connective tissue along this boundary contains abundant fenestrated capillaries that are exposed on one side to neurosecretory axons and on the other to cells of the pars distalis. Furthermore, secretory cells nearest these capillaries exhibit ultrastructural evidence of heightened secretory activity. We conclude that the fine structural characteristics of this zone are consistent with localized mechanisms of releasing hormone transport. © 1992 Wiley‐Liss, Inc.
Quantitative morphology of the embryonic heart: An approach to development of the atrioventricular valves
Authors: Wenink Arnold C. G.
Published: February 2005

In 32 human embryos ranging from 4.0 to 42 mm CR‐length, the volumes of the atrioventricular endocardial cushions and of the ventricular myocardium were estimated by the point counting method. The surface densities of the left and right ventricular apical trabeculations were estimated by the point and intersection counting method. It is concluded that the cushions do not grow after the 25 mm stage, by that time having reached the maximal value of 0.074 mm3. This supports the concept that the cushions do not materially contribute to the definitive atrioventricular valves. In young embryos, the left ventricular trabeculations are thicker (as concluded from their higher surface density) than the right ventricular trabeculations. Only around the 25 mm stage, the ratio becomes 1. After this stage, right ventricles have thicker trabeculations than left ventricles have. This supports the concept that the trabecular pattern is changed during the period of valve formation, which process is characterized by delamination of the inner myocardial layers. © 1992 Wiley‐Liss, Inc.
Effects of daily administration of prostaglandin E2 and its withdrawal on the lumbar vertebral bodies in male rats
Authors: Ke Hua Zhu , Jee Webster S. S.
Published: February 2005

The effects of daily prostaglandin E2 (PGE2) treatment (on) and PGE2 treatment followed by withdrawal (on‐off) on cancellous bone in lumbar vertebral bodies were studied in 7‐month‐old male Sprague‐Dawley rats. The first groups of rats were given daily subcutaneous injections of 0,1,3, and 6 mg PGE2 /kg/dfor 60, 120, and 180 days, and the second group of rats were given PGE2 for 60 days followed by withdrawal for 60 and 120 days. Histomorphometric analyses were performed on double‐fluorescent labeled undecalcified sections of fourth lumbar vertebral bodies. Systemic PGE2 treatment elevated cancellous bone mass of lumbral vertebral bodies 26–60% above control levels within 60 days and continued treatment maintained it for another 120 days, but the excess bone was lost after the treatment was withdrawn. PGE2 treatment for 60 days increased trabecular bone area, trabecular width, and bone formation parameters, and shortened remodeling periods in a dose‐response manner. These changes were sustained at the levels achieved by 60‐day treatment in the rats treated for 120 and 180 days. The eroded perimeter increased at day 60 and further at day 120 and then plateaued. In the on‐off treated rats, the cancellous bone area, bone formation, and resorption parameters returned to near agerelated controls by 60 days after withdrawal and were maintained there after 120 days of withdrawal. Therefore we conclude that the continuous treatment is needed in order to maintain the PGE2‐induced bone gain. When these findings were compared to those previously reported for the proximal tibial metaphyses, we found that the proximal tibial spongiosa was much more responsive to PGE2 treatment than the fourth lumbar vertebral body.© Willey‐Liss, Inc.
Migration and distribution of circumpharyngeal crest cells in the chick embryo
Authors: Kuratani Shigeru C. , Kirby Margaret L.
Published: February 2005

The cardiac neural crest is located in a transitional area on the neuraxis between trunk and cephalic regions and gives rise to both the dorsolateral and ventrolateral crest cell populations. Around stage 18 of chick development, a mass of E/C8+ cells surrounds the postotic pharyngeal arches and forms a crescent‐shaped arch, termed the circumpharyngeal ridge. Using immunohistochemistry and quail‐chick chimeras, it was determined that the E/C8+ cell mass located in the circumpharyngeal ridge derives from the dorsolateral component of the cardiac neural crest. The ventrolateral cell population of the cardiac crest is located more medially and shows long‐persistent HNK‐1 immunoreactivity dorsolateral to the foregut. The crest cells that populate the gut arise from the caudal portion of the circumpharyngeal crest and are always located caudal to the caudalmost pharyngeal ectomesenchyme. Circumpharyngeal crest cells continuously populate the pharyngeal arch ectomesenchyme and enteric nervous system on the lateral side of the foregut wall, as well as the hypoglossal pathway which develops within the ventral portion of the circumpharyngeal ridge. E/C8 and HNK‐1 immunoreactivity are associated with the cells migrating via the dorsolateral (circumpharyngeal) and ventrolateral pathways, respectively, with one exception: there is a population of putative crest cells along the proximal course of the vagal intestinal branch that shows both immunoreactivities around stage 20. Dil labeling of the cells in the circumpharyngeal ridge suggests that the cells are contributed from the circumpharyngeal ridge to this population. Thus, the distribution of the circumpharyngeal crest cells and their derivatives coincides with the peripheral branch distribution of the cranial nerves IX, X, and XII, whose development is selectively affected in the absence of the cardiac neural crest, the source of the circumpharyngeal crest.© Willey‐Liss, Inc.
Lymphoid cells in the harderian gland of the rodent Octodon degus
Authors: Tolivia Delio , Antolin Isaac , Menendez‐Pelaez Armando , Rodriguez‐Colunga Maria J.
Published: February 2005

The Harderian gland of the degu (Octodon degus) is composed of tubulo‐alveolar secretory units that share most of morphological features found in the Harderian glands of other rodents. However, a peculiar characteristic observed in the glands of female degus is the existence of lymphoid cell clusters within the connective tissue surrounding the secretory adenomeres. Lymphocytes and lymphoblasts are found associated with blood vessels and especially with nerve bundles in the medullary region of the gland. Occasionally, macrophages and plasma cells are also observed. Although the Golgi apparatus appears well developed, the ultrastructural characteristics of most of these lymphoid elements correspond to those of inactive lymphocytes. Unmyelinated fibers containing clear and dense‐core vesicles are found closely related to lymphocytes. On some occasions, lymphocytes present extensive areas of apposition with structures resembling intercellular junctions. The analogy of the lymphoid clusters reported in this study with those described in the avian Harderian gland is discussed.© Willey‐Liss, Inc.
Histological organization of the right and left atrioventricular valves of the chicken heart and their relationship to the atrioventricular purkinje ring and the middle bundle branch
Authors: Lu Ying , James Thomas N. , Bootsma Marianne , Terasaki Fumio
Published: February 2005

In the avian heart the right and left atrioventricular (AV) valves not only exhibit their own special anatomical characteristics, but they also are in close proximity to the conduction system. The right AV valve is a single, spiral plane of myocardium, in remarkable contrast to the fibrous structure characteristic of the mammalian tricuspid valve. A ring of Purkinje tissue encircles the avian right AV orifice and connects to the muscular valve. The chicken has no crista supraventricularis, its right AV valve serving that function as well as opening and closing the right AV orifice. The left AV valve consists of three leaflets instead of the two typical of mammalian hearts. Its anterior and posterior leaflets are small; its large aortic (medial) leaflet merges with the bases of both the left and noncoronary cusps of the aortic valve by fibrous tissue, resembling that of the mammalian heart. However, unlike in mammals, there is a slim cylinder of continuous myocardium coursing parallel to this fibrous junction. This unusual arc of myocardium in the chicken serves to complete an entire subaortic ring of myocardium and is thus potentially capable of constricting the outflow tract of the chicken's left ventricle. The middle bundle branch connects with both the muscle arch and the AV Purkinje ring. Thus the myocardium in or near both AV valves (and the left ventricular outflow tract) in the chicken heart is so arranged that it may receive direct early activation from the conduction system. ©1993 Wiley‐Liss, Inc.
Effects of prolactin on α and β chloride cells in the gill epithelium of the saltwater adapted tilapia “Oreochromis niloticus”
Authors: Pisam M. , Auperin B. , Prunet P. , Rentier‐Delrue F. , Martial J. , Rambourg A.
Published: February 2005

Tilapia (Oreochromis niloticus), 21 g average body weight, were divided into two groups. A group was maintained in fresh water, whereas another group was adapted for 2 weeks to 20% salt water. Among the latter, fishes were injected every 2 days for a week with tilapia prolactin (ti‐PRL I). Gills were prepared for electron microscopy in order to determine the types and surface areas of chloride cells in each experimental condition. Two types of chloride cells, the α and β cells were easily distinguished on the basis of their location and ultrastructural features in the gills of freshwater fishes, while only one type of cell, the saltwater α cells presumably derived from the transformation of the freshwater α cells, were encountered in saltwater adapted animals. After PRL injection ofsaltwater adapted fishes, small chloride cells, which displayed ultrastructural features similar to those of β cells in freshwater tilapia, reappeared in interlamellar regions of the gills. In the same experimental conditions, the voluminous saltwater α cells showed a tendency to resume ultrastructural features more characteristic of the freshwater α cells from which they were derived. These observations tend to indicate that prolactin behaves as a “freshwater adapting hormone” and that β cells are specifically involved in fish adaptation to freshwater living conditions. © 1993 Wiley‐Liss, Inc.
Immunohistochemical analysis of rat liver using a monoclonal antibody (HAM8) against gap junction
Authors: Fujikura Yoshihisa , Ohta Hidehiko , Hirai Toshio , Fukumoto Tetsuo
Published: February 2005

Four monoclonal antibodies were raised against crude gap junction fractions of rat liver to clarify the distribution of gap junctions during animal development and to analyze gap junction expression in vivo and the polarity of hepatocytes in vitro. Among the monoclonal antibodies obtained, HAM8 antibody recognized the 27‐kDa rat liver gap junction protein connexin 32. This antibody recognized gap junctions at the contiguous faces of hepatocytes, and the antigen was also observed in exocrine pancreas and salivary gland but not in kidney, heart, esophagus, or thymus. HAM8 did not react with amphibian or fish liver, heart, esophagus, stomach, or intestine as assessed via the immunofluorescence method on frozen sections. A few hepatocytes and many hemopoietic cells were seen in rat fetal liver at 15 days of gestation. HAM8 antigen was expressed on some hepatocytes but not on any hemopoietic cells. As the fetus grew, the number of hepatocytes in the liver increased gradually, together with the amount of HAM8 antigen. The distribution of HAM8 antigen at 25 days after birth was similar to that in adult liver. When the expression of HAM8 antigen was examined in primary cultured hepatocytes using the immunofluorescence method, the antigen was observed clearly between the hepatocytes. However, most of the HAM8 antigen on the free surface of hepatocytes disappeared within 4 hr. HAM8 antigen was not expressed on AH7974 rat hepatoma cells when they formed small islets in the rat peritoneal cavity or within the liver. When HAM8 IgG antibody was injected intravenously, the HAM8 signal was expressed in the liver. © 1993 Wiley‐Liss, Inc.