bluuebunny/crossref_metadata_2025_split huggingface dataset:
A histochemical study of the microvasculature in the left and right cardiac ventricles of the dog
Authors: Cannon M. Samuel , Jones Carl E. , Cannon Anita M. , Schultz Lucille H. 
Published: February 2005

AbstractSubepicardial and subendocardial arteries and arterioles in both the left and right normal canine ventricle were examined histochemically to determine their metabolic profiles. Aerobic metabolic capacity was assessed by determining the reactivities of the enzymes cytochrome oxidase, succinate dehydrogenase and NAD‐isocitrate dehydrogenase. Glucose‐6‐phosphate dehy‐drogenase was examin̈ed to assess activity of the hexose‐monophosphate‐shunt. The substrate glycogen was determined as an evaluation of anaerobic metabolic capacity, while the amounts of deoxyribonucleic and ribonucleic acid were assessed as an indication of protein synthesis. Results of the present investigation indicate that despite known hemodynamic differences, the metabolic profile of the coronary vasculature is similar in all regions of ventricular myocar‐dium. Reactivities of the enzymes succinate and NAD‐isocitrate dehydrogenase and cytochrome oxidase are greater in smooth muscle of arterioles than in arteries. This suggests that arteriolar smooth muscle has a higher capacity for aerobic metabolism than does arterial smooth muscle. The greater reactivity of glycogen in arterial, than in arteriolar smooth muscle, suggests that arterial muscle is more adapted for anaerobic metabolism. Deoxyribonucleic and ribonu‐cleic acids demonstrate a low reactivity in both arteries and arterioles from all regions of ventricular myocardium which conforms to the opinion that under normal conditions, coronary vasculature is quite stable with little cell proliferation. Glucose‐6‐phosphate dehydrogenase shows little reactivity in all myocar‐dial vessels which implies a low capacity for nucleic acid and protein synthesis.
Histochemical study of ovarian hydroxysteroid dehydrogenase activity during normal pseudopregnancy in the rat
Authors: Kovarik Frances A. , Velardo Joseph T. 
Published: February 2005

Abstract3β‐Hydroxysteroid dehydrogenase activity was localized in ovaries removed from rats during normal pseudopregnancy. Ovarian sections were incubated in media containing either pregnenolone (P‐one) or dehydroepiandrosterone (DHA). P‐one‐3β‐HSD activity appeared strongest on day 6 whereas DHA‐3β‐HSD was highest on day 13. NADH2 diaphorase activity was localized and observed to be greater than 3β‐HSD.Both P‐one‐ and DHA‐3β‐HSD activities were localized in primary‐, secondary‐ and tertiary follicles; granulosa and theca interna cells have a variable potential for steroidogenesis. Mature tertiary follicles appear most responsive of the follicular population in steroidogenic potential. In atretic follicles, theca interna cells showed a marked ability for potential steroid production and may be one of the more stable sites of steroidogenesis. Interstitial tissue is a major site for potential estrogenic and progestational biosynthesis during the functional life of the ovary. Luteal cells exhibited strong ability for DHA‐3β‐HSD activity during the ongoing process of pseudopregnancy while P‐one‐3β‐HSD activity declined in these cells as pseudopregnancy progressed. In summary, at the onset of pseudopregnancy, it appears that ovarian P‐one‐3β‐HSD activity is greater than DHA‐3β‐HSD activity. Near the termination of this condition, DHA‐3β‐HSD activity is greater than P‐one‐3β‐HSD activity in the rat.
Ultrastructure of the hepatic perisinusoidal cells in man and other mammalian species
Authors: Bartók I. , Tóth Jeannette , Remenár Éva , Virágh Sz. 
Published: February 2005

AbstractPerisinusoidal (P.S.) cells occurring in the spaces of Disse in the livers of normal cats, dogs, miniature pigs, albino rats, human adults and children were examined by electron microscopy. The ultrastructural details of the P.S. cells and their topographic relationships with hepatocytes, sinusoidal lining cells and reticulum fibers are described. Species differences between P.S. cells were primarily a dissimilarity in lipid content: the main ultrastructural features were the same in all species studied. The P.S. cells of the rat liver displayed only low endocytotic activity, and no phagosome formation following intravenous administration of horseradish peroxidase. The close topographic relationship of the P.S. cells with the intralobular reticulum fibers was reminiscent of the intimate connection between fibroblasts and collagen fibers, or, in cat liver, of the reticulum cell ‐ reticulum fiber association seen in lymphoid organs. Fibroblasts were not found inside the hepatic lobules. These findings support the conclusion that, the reticulum fibers of hepatic lobules are produced by perisinusoidal cells which, however, display also other functions.
Sites of lipoprotein production in the small intestine of the unsuckled and suckled newborn rat
Authors: Berendsen Peter B. 
Published: February 2005

AbstractThe size and distribution of lipoprotein particles in the intestinal epithelium were determined before and after the start of suckling by infant rats. Prior to suckling very low density lipoprotein particles were within the smooth endoplasmic reticulum (SER), rough endoplasmic reticulum (RER), Golgi apparatus and interepithelial cell spaces of duodenal villus tip cells. Chylomicrons were produced in the SER, RER and Golgi apparatus of duodenal epithelial cells after the commencement of suckling.Ileal epithelial cells did not contain particles of VLDL dimensions prior to suckling. Ileal cells of rats suckled for 24 hours after birth had VLDL particles in the SER, RER and Golgi apparatus above and at the sides of the large supranuclear vacuole in each cell. Ileal cells at 10 and 15 days of age had fewer and smaller particles. These particles were also present in the interepithelial cell spaces and lacteals.It is suggested that VLDL particles are produced by duodenal cells prior to suckling when only endogenous lipid is available. The ingestion of exogenous lipids in milk is associated with the production of chylomicrons by duodenal epithelial cells and VLDL particles by ileal epithelial cells. VLDL particles within ileal cells become smaller and less numerous as suckling continues, possibly due to increased pancreatic lipase. This is interpreted as evidence that chylomicrons and intestinal VLDL particles are related.
Corpus luteum growth and plasma progesterone levels in unilaterally ovariectomized pregnant rats
Authors: Meyer Geoffrey T. , Bruce Neville W. 
Published: February 2005

AbstractUnilateral ovariectomy (ULO) was carried out on rats at Day 8 of gestation: term is Day 23. The effect on peripheral plasma progesterone levels at Day 16 and on growth and cellular changes in the remaining corpora lutea (CL) at Day 17 was determined by comparison with results from control and sham‐operated rats. ULO increased the volume of remaining CL by 18% at Day 17. At Day 16 this effect was only apparent in rats with three or fewer CL remaining. CL hypertrophy was due to an increase in the volume of individual luteal cells and not to cell hyperplasia. Luteal cell nuclear volume also increased as did the number of endothelial cells per corpus luteum. The proportion of the corpus luteum occupied by vascular space did not alter.ULO had little effect on mean plasma progesterone levels at Day 16 (92 ± 7 ng/mltreated; 86 ± 11 ng/ml controls). In rats with three or fewer CL remaining, however, progeserone levels were low (51 ± 7 ng/ml).It was concluded that ULO can enhance the growth of corpora lutea and perhaps increase their rate of progesterone production.
Correlation of early cytodifferentiation of the human fetal prostate and leydig cells
Authors: Kellokumpu‐Lehtinen P. , Santti R. , Pelliniemi L. J. 
Published: February 2005

AbstractThe ultrastructural differentiation of the human prostatic epithelium and mesenchyme was studied in early developing glands and correlated with the differentiation of the Leydig cells of the same individuals during the tenth to sixteenth weeks.After initial folding of the basal lamina, the epithelial cells began to migrate into the differentiated, condensed mesenchyme at the end of the 10th week, and in the 11th week some of the prostatic outgrowths acquired a lumen. The acinar and tubular epithelium in the fetal prostate remained stratified, and adult type simple epithelium was not seen during the period between the 10th and 16th weeks. As a sign of incipient secretory activity, a few epithelial cells became polarized, and secretion granules with flocculent or dense content appeared in the Golgi area and in the apical parts of the cells in the 13th week. Occasional direct epitheliomesenchymal cell contacts were visible in association with the appearance of the secretory activity. Two cell types, not seen in the normal adult prostate, appeared in the epithelium of the primitive glands. Their nature and role in the glandular morphogenesis are not clear.During this time, the ultrastructural differentiation of the Leydig cells continued and their size and number increased. They occupied almost the whole in terstitium by the time secretion granules appeared in the prostatic cells. These findings support the current notion that androgens secreted by Leydig cells are the major regulators of prostatic development in man.
The effects of desiccated thyroid on the rat lung
Authors: Callas G. , Adkisson V. T. 
Published: February 2005

AbstractPressure‐volume characteristics of whole lungs were measured in euthyroid rats and in rats fed 0.4% desiccated thyroid for eight weeks. The lungs were degassed by incising the diaphragm after the animals had breathed 100% oxygen for ten minutes. The pressure‐volume characteristics were measured by inflating and deflating the lungs at a rate of 3.5 cc/min. Total lung capacity (TLC) was considered to be that volume of air required to produce a transpulmonary pressure of 30 cm H2O. At TLC there was 35% greater lung volume in the thyroid‐treated animals than in their littermate controls. Similar results were observed in saline‐filled lungs. Alveolar surface area (Sa) increased from 0.28m2 in the lungs of control animals to 0.75m2 in lungs of thyroid‐treated animals. There was an 85% increase in the alveolar surface density (Sva) in the thyroid‐treated animals. These results, obtained by morphometric analysis, suggest that greater lung volume in the thyroid‐treated animals resulted from alveolar hyperplasia or „partitioning”︁.
Growth patterns and hormonal profile of male rats with protein‐calorie malnutrition
Authors: Herbert Damon C. 
Published: February 2005

AbstractA condition of protein‐calorie malnutrition was precipitated in young Sprague‐Dawley male rats at 20 days of age using an 8% low protein diet (LPD). At five‐day intervals for up to 50 days of age, the rats were studied to determine the effect of an LPD on the reproductive axis of the endocrine system. Daily monitoring of the body weight, as well as the consumption of food, kilocalories, and protein was conducted. The same parameters were followed over the identical time peroid in a group of animals designated as controls which were fed a standard laboratory diet (SLD) containing 27% protein. The controls showed a linear growth rate over the 30‐day experimental period. In comparison, the malnourished rats grew more slowly so that by 50 days of age, their mean body weight was 68.9 ± 3.1 g as compared to 249.1 ± 6.1 g for the controls. The daily food, kilocalorie, and protein intake by the experimental animals were also appreciably less. The pituitary gland, ventral prostate gland, testes and liver were smaller in the animals fed the LPD. This was observed as early as five days after initiating the dietary regimes and remained a consistent observation until the end of the experiment. In general, the absolute weights of these organs in the 50 day‐old malnourished rats were similar to those found in 25 to 26 day‐old animals fed the SLD. The relative weights of the pituitary gland and liver remained similar between the two animal groups. The testes and ventral prostate gland, however, were relatively smaller in the malnourished animals at nearly every time interval studied. On light microscopic examination of the testes, it was found that normal maturation of the germ cells failed to occur in all but one of the experimental animals, whereas maturation proceeded normally in the rats fed the SLD. Serum luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin (PRL), and testosterone were lower in the malnourished animals at all ages studied. These hormones did not exhibit the fluctuations that were seen in the controls and are typical in rats that are becoming sexually mature. The effect of protein deficiency on the concentration of the pituitary gonadotrophins was more varied. FSH concentrations were consistently lower, PRL was moderately affected, and LH remained essentially unchanged. Hypothalamic LH‐releasing hormone was measured and found to be significantly less in the rats fed the LPD at most of the time intervals examined. These results indicate that the hypothalamo‐hypophyseal‐gonadal axis is impaired when the consumption of proteins and calories is decreased. The possible involvement of extrahypothalamic centers in the control of hormone secretion in the protein‐deficient rat is discussed.
Incidence and morphology of equine and murine chondrocytic cilia
Authors: Wilsman Norman J. , Farnum Cornelia E. , Reed‐Aksamit Debra K. 
Published: February 2005

AbstractThe incidence and structure of equine and murine chondrocytic cilia were studied using serial sections and transmission electron microscopy. Overall, 96% of all equine chondrocytes and 100% of all murine chondrocytes had one cilium. The structure of these cilia included rootlets, basal feet, alar sheets, and an axoneme of nine peripheral doublets which progressively bent and terminated as they coursed towards the tip of the ciliary shaft. Together with the previous studies on neonatal and adult canine chondrocytic cilia, we conclude that the structure and incidence of chondrocytic cilia does not vary among species, regions within a joint, cell types, or age groups.
Critique of “an electron microscope study of crystal calcium carbonate formation in the mouse otolith”
Authors: Peacor Donald R. , Rouse Roland C. , Ross Muriel D. 
Published: February 2005

AbstractElectron micrographs of otoconia of fetal mice, as obtained by Nakahara and Bevelander, provide morphological evidence that the otoconia consist of both organic material and calcium carbonate (calcite), contrary to their own conclusions. Calcite is an integral component of otoconia, apparently from their inception. The concept of mineralization by calcite of an already developed organic template (“preotolith”) is shown to be in error.
The myelinated fibers of the deep branch of the ulnar nerve at the wrist in bonnet monkeys (Macaca radiata) and of some of its branches to the hand
Authors: Devanandan M. S. , Ghosh S. , Simoes E. A. F. 
Published: February 2005

AbstractIn order to estimate the peripheral nervous correlates concerning the motor performance of the hand, the myelinated fibers of the deep ulnar nerve and some of its branches to the intrinsic muscles of the monkey (Macaca radiata) hand have been enumerated and their caliber spectra plotted. The content of the myelinated sensory fibers in the deep ulnar nerve was found to be 70% of the total. This high figure is attributable to the fact that 25‐50% of the myelinated fibers in the deep ulnar nerve are destined to innervate the joints of the hand. Approximately 50% of the myelinated fibers in nerves to the intrinsic muscles of the hand were sensory.
Changes in intramembranous particle distribution in the plasma membrane of didelphis virginiana spermatozoa during maturation in the epididymis
Authors: Olson Gary E. 
Published: February 2005

AbstractStructural specializations in the plasma membrane of opossum spermatozoa obtained from different levels of the epididymis have been analyzed in thin sections and freeze‐fracture replicas. The maturation process was accompanied by a redistribution of intramembranous particles in the flagellar midpiece region. Caput epididymal spermatozoa are immotile, and freeze‐fracture replicas of the midpiece plasma membrane reveal a random arrangement of intramembranous particles. As spermatozoa transit the corpus epididymis, the intramembranous particles in the midpiece plasma membrane are redistributed from a random arrangement to an organized packing pattern. This redistribution apparently involves the formation of chains of intramembranous particles which gradually increase in length, orient parallel to the flagellar long axis, and ultimately form numerous parallel rows, each three to five particles wide. In cauda epididymal spermatozoa the intramembranous particles within the rows are packed in an organized manner, and few free intramembranous particles are noted between rows. Analysis of thin sections revealed that the reorganization of intramembranous particles is accompanied by the deposition of a mat of amorphous material at the cytoplasmic face of the membrane. No striking changes in intramembranous particle distribution during epididymal maturation were found in other flagellar segments or in the plasma membrane overlying the sperm head.
Histology of the canine urethra. I. Morphometry of the female urethra
Authors: Cullen W. Craig , Fletcher Thomas F. , Bradley William E. 
Published: February 2005

AbstractUrinary bladders and urethrae were collected from six adult and two juvenile female dogs. Five urethral regions and the neck and body of the bladder were sampled. Volume fractions for connective tissue including elastic fibers, smooth and striated muscle, and epithelium were obtained by projecting section images onto an array of points and computing the number of points overlying a tissue constituent per total points overlying the tissue section.Smooth muscle occupied approximately half the volume of the bladder wall, one‐third the volume of the vesical neck, and one‐fourth the volume of the proximal urethra. Striated muscle was present in the distal half of the urethra, where the total muscle coat occupied about one‐third of the urethral wall volume. Smooth muscle was practically absent in the terminal urethra, where the striated urethralis muscle encircles urethra and vagina in common. Epithelial area and lumen perimeter were not significantly different along the length of the urethra except that urethral epithelium was significantly thicker adjacent to the vesical neck. In terms of histological proportions, the vesical neck was intermediate between the body of the bladder and the proximal urethra.
Developmental changes in the fine structure of the chorion laeve (Smooth chorion) of the rhesus monkey placenta
Authors: King Barry F. 
Published: February 2005

AbstractDevelopmental changes in the fine structure of the chorion laeve (smooth chorion) of the rhesus monkey were studied at two time periods during gestation: (1) Early (19–60 days of gestation), before the chorionic epithelium fuses with the parietal decidua, and (2) near term, when the fused chorioamnion has also fused with the parietal decidua. Early in gestation the chorionic epithelium consisted of columnar and cuboidal cells one or two layers thick. The apical border of the cells had microvilli and coated pits, and adjacent cells were joined by tight junctions and desmosomes. The chorionic epithelial cells during this early period contained numerous large vesicles and vacuoles of varying electron‐density. The apical cytoplasm contained various small coated vesicles and tubules. Taken together these observations were interpreted as indicating a possible role for these cells in endocytosis or phagocytosis of substances from the uterine lumen; i.e., a potential role in histiotrophic nutrition during this early period. Late in gestation the trophoblastic cells were more irregular in shape. The cells contained abundant granular endoplasmic reticulum (ER) and mitochondria, and a well‐developed Golgi complex, suggesting the cells were actively synthetic late in gestation. The numerous cytoplasmic vacuoles characteristic of the trophoblastic cells of early gestation were absent near term. Glycogen deposits and lipid droplets were moderately well‐developed near term. Most of the cells were joined by desmosomes but wide intercellular spaces, unobstructed by any cell junctions, were frequently observed. This observation provides at least one explanation for the increase in permeability of the chorion laeve later in gestation. Cells of the parietal decidua associated with the chorion laeve were also examined. These cells generally had a well‐developed granular ER and Golgi apparatus, and numerous mitochondria. Limited numbers of membrane‐bounded secretory bodies, similar to those in human decidual cells, were also present.
Stereotaxic placement of cannulae in cerebral ventricles of the pig
Authors: Poceta J. Steven , Hamlin Michael N. , Haack David W. , Bohr David F. 
Published: February 2005

AbstractWe have developed and employed a stereotaxic coordinate system for the pig brain based on external skull landmarks. Sagittal, coronal, and horizontal planes were defined. Based on histological maps and ventricular casts, the coordinates for locating the lateral ventricles were described. Guide tubes leading to the lateral ventricles have been chronically implanted. This access route to the ventricular system has been used for stimulation of the dipsogenic response with angiotensin and for withdrawal of cerebrospinal fluid. Solved and unsolved problems arising with these procedures have been defined.