bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of growth on architecture of rat semimembranosus lateralis muscle
Authors: Willems Mark E. T. , Huijing Peter A. 
Published: February 2005

AbstractArchitecture 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

AbstractGonadotrophs 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

AbstractAlthough 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

AbstractWe 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

AbstractA 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

AbstractCoronary 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

AbstractThe 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

AbstractProximal 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

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractIn 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

AbstractThe 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

AbstractThe 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

AbstractThe 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.