bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three‐dimensional organization of testicular interstitial tissue and lymphatic space in the rat
Authors: Clark Richard V. 
Published: February 2005

AbstractRat testes fixed by vascular perfusion were examined by scanning and transmission electron microscopy. This revealed a complex organization of the interstitial tissue and an extensive “testicular lymphatic space” composed of continuous “peritubular lymphatic sinusoids.” No cellular connections exist between the interstitium and the tubules. Each sinusoid completely surrounds an individual seminiferous tubule, and adjacent sinusoids communicate freely through fenestrae in the interstitium. Thus, material must enter the lymph to gain access to the tubules. The sinusoids are delimited by separate endothelial cell layers over the tubules and interstitium. The layer over the interstitium is discontinuous in specific areas according to the geometry of the tubule packing. Interstitial tissue located in the flattened biconcave interstices between two adjacent tubules is consistently covered with endothelial cells, while that located in the open, triangular interstices between three or more tubules consistently lacks an endothelium. Most of the Leydig cells are located in the “open interstitium” and are directly exposed to the lymph. Physiological implications of the “testicular lymphatic space” and additional features of the interstitium are discussed.
Demonstration of a cytochemical difference between the tubulovesicles and plasmalemma of gastric parietal cells by ATPase and NPPase reactions
Authors: Rubin Walter , Aliasgharpour Ali A. 
Published: February 2005

AbstractPieces of rat and human gastric mucosa were fixed in glutaraldehyde and paraformaldehyde and were processed by the methods of Wach‐stein‐Meisel and of Ernst for the cytochemical demonstration of adenosine triphosphatase (ATPase) and p‐nitrophenylphosphatase (NPPase) respectively. Electron microscopic examination of reacted sections revealed the ATPase reaction to be localized to the plasmalemma and to mitochondrial cristae and the NPPase reaction to the plasmalemma. The tubulovesicles were unreactive. By thus demonstrating a cytochemical difference between the plasmalemma and tubulovesicle membrane, this study suggests that the tubulovesicles do not represent an extension of or reserve of mature plasmalemma. If the tubulovesicles represent a reserve of membrane that can be rapidly utilized to expand the plasmalemma, then these studies suggest that additional membrane constituents are added, activated, or unmasked in the process.
Ciradian rhythm in DNA synthesis in mouse thymus: Effect of altered lighting regimens, restricted feeding and presence of Ehrlich ascites tumor
Authors: Pauly John E. , Scheving Lawrence E. , Burns E. Robert , Tsai Tien‐Hu 
Published: February 2005

AbstractA circadian rhythm in the incorporation of tritiated thymidine into DNA of the mouse thymus has been described. This same rhythm in animals bearing an 8‐day Ehrlich ascites tumor (EAT) was altered in its phasing, wave‐form and over‐all 24‐hour mean; the most striking alteration seen in four out of five studies was a reduction in the over‐all DNA synthesis rate in tumor‐bearing animals.Mice subjected to an altered light‐dark cycle did not show a complete phase shift in their thymus DNA rhythm within two weeks, but during this time the rhythm in the mitotic index of their corneal epithelium completely phase shifted; the presence of the tumor had no effect on this latter rhythm. In mice subjected to a daily 4‐hour restricted feeding schedule, the rhythm in DNA synthesis in the thymus became synchronized in that the peak occurred toward the end of the 4‐hour restricted feeding span in both tumor and non‐tumor‐bearing animals. The rhythm in the mitotic index in the cornea was not phase shifted or altered by the restricted meal timing.The DNA synthesis rhythm in the normal thymus demonstrated a phasing similar to (1) the rhythm in the length of survival time in untreated mice challenged with EAT and (2) the rhythm in DNA synthesis in the normal spleen.
Quantitative studies of lymphocytes and other cell populations in the bone marrow of neonatally thymectomized C3H mice
Authors: Miller S. C. , Osmond D. G. 
Published: February 2005

AbstractThe effects of neonatal thymectomy on the development of the lymphoid, erythroid and granulocytic cell populations in mouse bone marrow have been assessed by quantitative techniques. The numbers per unit volume of bone marrow of 17 cell types were determined in neonatally thymectomized and sham thymectomized C3H mice at two, four and eight weeks of age, and compared with those of normal C3H mice. After neonatal thymectomy the numbers of small lymphocytes, large and medium‐sized lymphoid cells, and erythroid cells reached normal levels at two weeks but fell progressively to 18%, 22% and 42% of normal, respectively, by eight weeks. In sham thymectomized mice these cell populations did not differ significantly from normal. Immature and mature granulocytes were elevated in numbers two weeks after either neonatal thymectomy or sham thymectomy, suggesting a transient non‐specific stimulation of granulocytopoiesis. During continuous infusion of 3H‐thymidine for ten days in neonatally thymectomized mice aged four weeks and eight weeks many bone marrow small lymphocytes remained unlabeled. The results demonstrate that early postnatal development of bone marrow lymphoid and erythroid cells proceeds normally in the absence of the thymus, in accord with the concept of the bone marrow as a primary site of lymphocyte production and differentiation. In addition, some slowly‐renewing small lymphocytes in bone marrow appear to be thymus‐independent cells.
Reproductive biology of the male leaf‐nosed bat, Macrotus waterhousii in Southwestern United States
Authors: Krutzsch Philip H. , Watson Robert H. , Lox Charles D. 
Published: February 2005

AbstractThe reproductive biology of the bat Macrotus waterhousii was investigated anatomically and physiologically several times monthly throughout the year.The male spermatogenic cycle is initiated in June; sperm are available in August. Testicular hypertrophy is accompanied by increased levels of testicular ascorbic acid and circulating plasma testosterone. Sperm are present in the seminiferous tubules and later the epididymides from August to early December. Regression in testicular size begins in late September and testes are involuted by early December. Levels of testicular ascorbic acid and plasma testosterone decline at this time, although detectable amounts of both are present year‐round. Mature sperm are absent from the male tract after late November or early December.The accessory sex gland complex and Cowper's glands undergo an annual cycle in synchrony with the testicular cycle. The accessory complex contains fructose, the concentration of which varies seasonally in direct proportion to glandular hypertrophy. Only trace levels of fructose are elaborated by Cowper's glands.In contrast to vespertilionid bats, where the accessory glands remain enlarged and active when testes involute, those in Macrotus regress.The penis differs structurally from that of other temperate North American bats, primarily by lacking a bony baculum and specialized erectile accessory corpus cavernosus bodies.Males are not reproductively active in their first autumn.
Uterine vasculature of the pregnant pig: A scanning electron microscope study
Authors: Macdonald Alastair A. 
Published: February 2005

AbstractColored cold setting acrylic cement was injected through catheters into the arteries and veins of sixteen gravid uteri obtained from pigs at various stages of pregnancy. After the cement had set hard, the reproductive tracts were macerated in concentrated acid and the vascular casts resulting were washed clean of digested tissues. Small pieces of cast were coated with gold and viewed by means of a scanning electron microscope.Early in pregnancy the capillary network consists of low parallel ranks of ridges and troughs; later, cross ridging was observed which developed in complexity as pregnancy progressed. The density of capillaries comprising the microvascular network also increased towards term. No comparable changes were noted in the relatively less well vascularized areas surrounding the mouths of the uterine glands.This technique surmounted the problems of obtaining an adequate depth of focus for viewing the capillary network of the gravid uterus with the light microscope. The relationships that the blood vessels bore to the overlying epithelial layers were discussed and the inference tentatively drawn that blood flow at the capillary level was from ridge top to trough base.
Folliculogenesis in the ovary of the mature mouse: A radioautographic study
Authors: Hoage Terrell R. , Cameron Ivan L. 
Published: February 2005

AbstractStudies on the growth sequence of follicles in mature mice four to six months old were conducted by giving three injections of 16 μCi tritiated thymidine (3H‐T) / gm body weight at four hour intervals over a period of eight hours. Subsequent radioautographic analysis on ovaries obtained 1, 3, 5, 9 and 17 days after the last injection showed an overall follicle growth time of 17 to 19 days. The duration of the different follicle stage times were also estimated from radioautographic data. Intense 3H‐T incorporation was noted in the developing antra and zona pellucida of follicles of animals sacrificed one and three days after treatment suggesting that these areas serve as precursor storage sites during development. Oocytes of follicles in early antrum formation also showed juxtanucleolar 3H‐T incorporation concomitantly with rapid and massive oocyte and follicular growth. The findings further indicate that the earliest follicular cells surrounding the oocyte originate at some distance from the developing primordial follicle.
Microblebs of intestinal epithelial cell microvilli of Citellus tridecemlineatus
Authors: Dougherty William J. 
Published: February 2005

AbstractThe presence of microblebs arising from the lateral surfaces and tips of microvilli of intestinal epithelial cells of thirteen‐lined ground squirrels. Citellus tridecemlineatus, is reported. Microblebs measure ∼ 50 nm in diameter and are bounded by a unit membrane which is continuous with the unit plasma membrane of the microvilli. It is suggested that such microblebbing reflects the rapid turnover of microvillar contents, membrane and surface coat.
Fine structure of tracheo‐bronchial epithelial nerves of the cat
Authors: Hung Kuen‐Shan 
Published: February 2005

AbstractThe nerves in and immediately under the epithelial layer of the trachea and primary bronchi of the cat are studied with the electron microscope. The axons are unmyelinated and contain microtubules and mitochondria. Epithelial axons are observed throughout the entire epithelial layer, but, are usually concentrated in the basal area immediately above the basal lamina. Most axons are near the basal cells; others are in the vicinity of granulated cells or occur in the intercellular spaces between other columnar cells. A few of the epithelial axons are large and crowded with axoplasmic mitochondria. The possibility that some epithelial axons may have sensory functions is discussed.
Ciliated and secretory epidermis produced from embryonic mammalian skin in organ culture by vitamin A
Authors: Sweeny Phillip R. , Hardy Margaret H. 
Published: February 2005

AbstractWhen skin from the upper lip of 12‐day embryonic mice was grown for ten days in organ culture with 5.7 μg retinol added per ml of biological medium, keratinization was suppressed and a ciliated and secretory epithelium was produced. Ultrastructural features of this epithelium are described. At this very early stage mouse epidermis is thus similar to chick epidermis in its ability to undergo radical metaplasia in response to vitamin A.
Variation in form of circle of willis: Some anatomical and embryological considerations
Authors: Puchades‐Orts A. , Nombela‐Gomez M. , Ortuño‐Pacheco G. 
Published: February 2005

AbstractThis work is based on a study of 62 circles of Willis (circulus arteriosus cerebri) from patients dead from diverse causes. We have described the wide diversity of variations found to be present in the arterial vessels that form the circle, we presented the frequency of the different variations, and finally we discuss the possible ontogenic cause of these variations.
Catecholamine‐sensitive adenylate cyclase in the developing golden hamster palate
Authors: Waterman Robert E. , Palmer Gene C. , Palmer Shelby J. , Palmer Susan M. 
Published: February 2005

AbstractThe present study was initiated to determine whether specific hormones would influence adenylate cyclase activity within the maxillary‐palatal complex during formation of the hamster secondary palate. Stages from initial appearance of the palatal processes to shortly after birth were studied. Highest basal adenylate cyclase activities occurred during the earliest periods of palate development. This basal enzyme activity began to diminish as palatal fusion occurred and remained lowered until birth. Activation of adenylate cyclase by fluoride was maximal at concentrations of 5–10 mM, and was observed throughout the span of palatal development. Fluoride activation of adenylate cyclase was greatest prior to fusion of the palatal processes, then decreased until birth when a slightly increased enzymatic stimulation was seen. Norepinephrine and epinephrine were the catecholamines most capable of inducing increased activation of adenylate cyclase at most periods of palatal growth. Increased enzyme activity in the presence of norepinephrine was more susceptible to antagonism by the beta adrenergic agent, propranolol, than to the alpha adrenergic agent, phentolamine. The remaining catecholamines, namely isoproterenol and dopamine, displayed a lesser ability to activate the enzyme, and adenylate cyclase was not equally responsive to these catecholamines at identical developmental stages. Other hormones, i.e., histamine, serotonin, thyrotropin, growth hormone, thyroxine and glucagon were generally ineffective in activating the enzyme. Phosphodiesterase activity was not detected until shortly before birth.
Surface morphology of human aorta as revealed by the scanning electron microscope
Authors: Albert E. N. , Nayak R. K. 
Published: February 2005

AbstractHuman aorta was prepared for scanning electron microscopy using critical point drying. The aortic surface is lined by a continuous layer of squamous endothelial cells. The luminal surface of these cells contains many microvilli or microappendages and pinocytotic vesicles. In addition, at the periphery of each cell, larger marginal appendages or microfolds are present which allow the observer to see the cell boundaries clearly. The marginal folds are superficial to the cell junctions and could be observed without any staining procedures. These observations on human aorta are generally in agreement with our findings on the rabbit and guinea pig aorta and vena cava but are in contrast to others who have reported the presence of ridges, intercellular bridges, and “hair‐like” processes on the endothelial surfaces.
The biosynthesis and secretion of precursor enamel protein by ameloblasts as visualized by autoradiography after tryptophan administration
Authors: Slavkin Harold C. , Mino William , Bringas Pablo 
Published: February 2005

AbstractThe incorporation of 3H‐tryptophan into the inner enamel epithelium of newborn mouse incisor tooth organs has been studied in situ by light and electron microscopic autoradiography to determine the sites and kinetics of biosynthesis, migration, and secretion of precursor enamel protein during newborn mouse incisor tooth formation. Maxillary and mandibular incisor tooth amelogenesis was studied 5, 30, 60, 120, 240 minutes and 24 hours following the intraperitoneal injection of 3H‐tryptophan. By 5 minutes, 40% of the total silver grains associated with the secretory ameloblasts were localized over the rough endoplasmic reticulum and 50% of the silver grains were localized over the Golgi apparatus. By 30 minutes, silver grains were observed predominately over condensing vacuoles and secretory granules within the forming Tomes' processes, and were also localized over the extracellular “granular” pre‐enamel matrix. The enamel proteins were synthesized on membrane‐bound polysomes, transferred within the cisternae of the rough endoplasmic reticulum and then accumulated in the inner saccules of the Golgi apparatus. The enamel proteins were then packaged in condensing vacuoles which subsequently became secretory granules which migrated to the lateral and apical secretory regions of the forming Tomes' processes. It was concluded from these in vivo studies that enamel proteins were synthesized and subsequently secreted within 30 minutes. The initially secreted precursor enamel protein was localized over a material which demonstrated a granular or stippled ultrastructure. The labeled protein then was localized over the amorphous enamel matrix per se which contained the forming calcium hydroxyapatite crystals. We assumed, therefore, that there are two different ultrastructural forms of 3H‐tryptophan containing extracellular enamel proteins and suggest that the granular or “stippled” form represents newly secreted precursor enamel protein.
The exfoliating cervico‐vaginal surface. II. Scanning electron microscopical studies during the estrous cycle in mice
Authors: Rubio C. A. 
Published: February 2005

AbstractThe exfoliating epithelial surface of the ectocervix (pars vaginalis) and the vagina from normal mice was studied by scanning electron microscopy during the four main phases of the ovulatory cycle, and after estrogen administration. At proestrus, the epithelial surface usually presented cobblestonelike structures furnished with thin microvilli; at estrus, large, flat mosaics covered by long, convoluted microrugae; at metestrus, the presenting cellular surfaces were of intermediate size (i.e., between cobblestone and mosaics) having fragmented microrugae; and at diestrus, by mosaics or intermediate structures covered by microvilli. Estrogen administration to intact and oophorectomized animals resulted in flat mosaics and large numbers of loosely attached cells with rolled‐up borders which permitted the observation of the basal surface of the cells. In those animals the apical aspect of the cells which lined the lumen showed convoluted microrugae with circular configuration, while the basal aspect of such cells had club‐tipped microvilli. The findings were correlated with post‐scanning histological examination in all animals.
Adrenergic and cholinergic innervation of the arteriovenous anastomosis in the rabbit's ear
Authors: Iijima Tadahiko , Tagawa Takasuke 
Published: February 2005

AbstractThe distribution of adrenergic and cholinergic nerves in the arteriovenous anastomosis in the rabbit's ear was studied light microscopically using specific histochemical techniques for catecholamines and acetylcholinesterase.Histochemical observations were made with whole stretch preparations and cryostat or paraffin sections. Both kinds of nerves showed similar distribution, though the adrenergic innervation was denser than the cholinergic one. The intermediate segments of the anastomoses, which were characterized by a very thick wall, had the most dense innervation. The small arteries and arterial segments had a moderate innervation, whereas most of the small veins and venous segments had few nerve fibers.The segmental variation in the vasomotor nerve supply clearly suggests that the intermediate segment has the most active contractility. An unusually rich innervation in the anastomosis, therefore, indicates the significance of the neurogenic mechanisms in the vasomotor control of the anastomosis.
A scanning electron microscope study of the interstitial tissue of the canine testis
Authors: Connell Carolyn J. 
Published: February 2005

AbstractScanning electron microscopy (SEM) is a potent tool that is especially valuable in interpreting the three‐dimensional relationships of cells within tissues. This type of information is obtainable from thin sections in transmission electron microscopy (TEM) only by reconstructions of serial sections. The arrangement of the interstitial cells of the testis in relation to the capillaries and lymphatic channels, in particular, is easier to visualize in SEM than in TEM. Cytoplasmic constituents, as well as cell surface modifications, are demonstrable by this technique. The presence of droplets, presumably lipid droplets, both within and on the Leydig cells and the lymphatic endothelial cells, is quite evident. Other cytoplasmic structures are also apparent. For example, the possible functional significance of “openings” that are seen by SEM on the septa that surround lipid droplets is discussed relative to the appearance of the same area as seen in thin sections or in freeze‐fracture replicas. SEM should become a very useful method for studying cytological and morphological alterations that occur in testicular tissue that is subjected to physical or chemical manipulation.
Analysis of cell populations of normal and injured mouse lens epithelium. I. Cell cycle
Authors: Rafferty Nancy S. , Smith Richard 
Published: February 2005

AbstractUsing a combination of single isotope and double isotope autoradiography after injection of 3H‐thymidine and of 3H‐ + 14C‐thymidine, respectively, the cell cycle of normal and injured lens epithelial cells in the mouse was determined. Progenitor cells in the peripheral region of normal lens epithelium were found to traverse the replicative cycle in the same amount of time as the injury‐stimulated cells in both peripheral and central (wound) regions. The individual phases were also the same length, except for a slight shortening of G2 in the injured epithelium. The durations of the phases were: S: 11–12 hours; G2: 1.5–2 hours; M: 4.2–5 hours; G1 (derived): 38–44 hours; and total cycle: 55–61 hours. Two findings were significant in view of previous observations that injury to mouse lens seldom induces lens opacity. First, while the cell cycle duration was not affected by injury, a burst of proliferation of potentially active cells ensued. And, secondly, this burst of proliferation involved only one cell cycle. Only a small number of cells, equivalent to the normal progenitor compartment, continued into a second replicative cycle. The wound was healed, therefore, mainly by one division cycle involving a large number of cells.
Histochemical evidence of mucosubstances in the metaplastic epidermis and hair follicles produced in vitro in the presence of excess vitamin A
Authors: Bellows Carlton G. , Hardy Margaret H. 
Published: February 2005

AbstractPieces of upper lip and lower jaw from 13‐day old mouse embryos grown in organ culture with excess vitamin A showed metaplastic changes in epidermis and hair follicles after 7 to 21 days. Changes were less marked in upper lip explants from 15‐day old embryos. Areas of keratinizing epidermis showed a much higher incidence of Alcian blue‐positive bodies when excess vitamin A was present. Histochemical tests with Alcian blue at critical electrolyte concentrations indicated moderately sulfated acidic mucosubstances in these bodies. Other patches of epidermis were transformed into stratified cuboidal epithelium producing PAS‐positive. Alcian blue‐negative, mucosubstances. The hair follicles, transformed by vitamin A into glands, developed three types of epithelium with apical granules, luminal borders and occasional goblet cells, all showing mucosubstances. Tests suggest that both metaplastic epidermis and glands secrete either neutral mucosubstances or non‐sulfated acidic mucosubstances. Another response to vitamin A was a rapid loss of glycogen, particularly in hair follicles and the epidermal basal layer. It was concluded that excess vitamin A alters not only the morphogenesis but also the distribution and synthesis of polysaccharides in developing skin.