bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface area ratios II. A stereological method for estimating changes in average cell volume and frequency
Authors: Bolender Robert P. 
Published: February 2005

AbstractThe study describes a stereological method for detecting relative changes in cells‐with respect to their average volumes and to their frequencies within one cm3 of exocrine cells. The method is based on surface area ratios (Bolender, '1979) and can detect changes comparable to those obtained with the numerical density approaches (Loud, '68; Weibel et al., '69; Bolender, '74; Williams, '77). The new method requires only intersection counts‐ the same ones that are used for surface density estimates‐ and, as a result, avoids the difficult and often problematic procedures of the numerical densities. In analyzing the cellular changes in vitro, the choice of either a zero or timed control was found to exert a major influence on the results. Timed controls were required to “isolate” the experimentally induced changes from those Produced by the incubation medium.
The course, relations and distribution of the inferior alveolar nerve and its branches in the cat
Authors: Robinson P. P. 
Published: February 2005

AbstractThe course, relations and distribution of the inferior alveolar nerve and its branches in the cat are described. The nerves have been studied by dissection, histologically and by using electrophysiological techniques. Dissection revealed a basic pattern on which some individual variation was Superimposed. The inferior alveolar nerve has three branches Supplying thealveolar process (alveolar branches), one branch SUPPLying the canine and incisor region (caninelincisor branch) and four mental branches (posterior, mainand 2 anterior). Fibres Supplying the teeth were found in all except the mental branches. pulpal, periodontal and buccal gingival margin fibres from an individual tooth generally travelled together, but often in more than one branch. Branched axons Supplying both tooth pulp and an area of mental skin were found. The axons branched a t the point of separation of the appropriate mental nerve from the main trunk. A cutaneous midline overlap of 1–2 mm was found, but there was no transmedian innervation of tooth pulps.
Maturation of the proximal tubule in the puppy kidney:A comparison to the adult
Authors: Hay Don A. , Evan Andrew P. 
Published: February 2005

AbstractTwo‐ to four‐ day‐ old beagle puppy kidneys were prepared fortransmission and scanning electron microscopy and compared to similarly prepared adult tissues. proximal tubules of puppy kidneys which contained nephrons in various stages of differentiation were examined andmaturational changes were described. Lateral surface contours of proximal tubular cells were initially smooth and relatively unfolded, but progressively acquired complex processes that may be recognized as lateral ridges and lateral‐basal processes. Basal projections began as short, stubby processes and gradually took on either a narrow, plate‐like or finger‐like appearance. Mitochondria, lysosomes and apical vacuoles increased in number as the tubules matured. Mitochondria lacked orientation in outer cortical tubules, but exhibited some vertical arrangement within basal processes in inner cortical tubules. Despite features indicating advanced maturation of tubules in the inner cortex, puppy kidneys lacked the lipid droplets characteristic of the adult. Thus, differentiation of this portion of the developing nephron into S, S2 and S, segments was notpossible at day 4.Morphometric analyses of the lateral and basal membrane surface concentrationof proximal convoluted tubules from the puppy revealed all cells to have significantly smaller membrane area than that of the adult. However, the inner cortical cells of the puppy had a greater surface concentration than those of the outer cortex. The reduced transport capacity of the puppy proximal tubule may be related to the lack of segmentation and/or reduced lateral‐basal surface area.
Cytological events associated with in vitro aged and fertilized rabbit eggs
Authors: Meyer Norman L. , Longo Frank J. 
Published: February 2005

AbstractThe morphogenetic events associated with rabbit eggs aged in vitro for 12 to 50 hours prior to mixing with sperm have been examined by light and electron microscopy. After 12 hours in culture, morphological alterations of the meiotic spindle and the cortex of unfertilized eggs were evident. By 24 to 50 hours in culture, unfertilized eggs contained subnuclei, structures which formed when individual and/or groups of meiotic chromosomes dispersed and became invested by a double‐laminated structure reminiscent of a nuclear envelope.Although most eggs obtained 11.5 to 12 hours after induced ovulation and in vitro fertilized displayed morphogenetic patterns similar to those described for in vivo fertilized ova, some (10%) contained three pronuclei. Many eggs obtained 13 to 15 hours after induced ovulation and subsequently mixed with sperm in vitro appeared to undergo processes of fertilization typical of in vivo fertilized eggs, however, approximately 30% contained subnuclei in association with the male pronucleus. Few eggs (15%) aged 12 hours prior to in vitro fertilization displayed patterns of pronuclear development and association typical of fertilized unaged ova. Subnuclei developed in many of the fertilized ova. Supernumerary sperm nuclei, which did not develop into male pronuclei, were observed in some zygotes. Cleavage of eggs aged 12 hours prior to fertilization was abnormal or retarded. After 24 hours in culture approximately 16% of the eggs fertilized. Seventy percent of the fertilized eggs failed to Support the development of a male or female pronucleus.
Effect of uncouplers of oxidative phosphorylation on microtubule location and surface structure in murine mast cells
Authors: Bergstrom‐Porter Beverly , Shelton Emma 
Published: February 2005

Abstract“Uncouplers” of oxidative phosphorylation (sodium azide, DNP, and oligomycin) alter the location of microtubules within murine mast cells. Both cytoplasmic microtubuless, perpendicular to the plasma membrane within cell surface folds, and intranuclear microtubules wereobserved. In addition, one or more dense plaque‐like structures adjacent the plasma membrane in mast cells appeared following incubation in the antimetabolities. Intranuclear microtubules and cytoplasmic microtubules within the cell surface ridges disappeared in azide‐treated mast cells that were reincubated or “recovered” in PBS. However, both these structures remained in oligomycin‐ and DNP‐treated murine mast cells following reincubation.
Induction of exocytosis from glomus cells by incubation of the carotid body of the rat with calcium and ionophore A23187
Authors: GröUnblad Mats , EräUnköU Olavi , Erikärkerman Karl 
Published: February 2005

AbstractCarotid bodies from adult rats were electron microscopically studied after incubation in glucose‐containing salt solutions containing calcium and/or ionophore A23187 or neither. In the absence of the ionophore, adding or omitting calcium had no effect on the fine structure of theglomus cells. Incubation in the medium containing both 1 mM calcium and the ionophore caused the appearance of exocytotic membrane profiles in several glomus cells. Exocytosis was not seen when only A23187 and endogenous calcium was present. For exocytosis to occur, calcium appeared to be essential and the event seemed to be due to a rise in the intracellular calcium concentration caused by the ionophore.
Milk lipid absorption and chylomicron production in the suckling rat
Authors: Berendsen Peter B. , Blanchette‐Mackie E. Joan 
Published: February 2005

AbstractStructural correlates of milk lipid absorption and chylomicron production were studied in 10‐day‐old suckled rats. The gastric and duodenal contents and duodenal mucosae were examined with the light and electron microscopes. In the gastric lumen the milk lipid globule cores were smooth, circular and uniformly electron opaque. Many membranes and lamellar structures with a trilaminar and multilamellar appearance were adherent to the peripheries of the cores. In the central duodenal lumen the milk lipid globule cores were also smooth, circular and uniformly electron opaque. Very few milk lipid globules in the duodenal lumen showed adherent membranes or lamellae. Membrane fragments and lamellae were present in the lumen separate from the milk lipid globules. In the duodenal lumen between villi the milk lipid globules had multiple electron lucent indentations of the core. It is believed that the irregular peripheries of the milk lipid globule cores are the result of lipolysis within the duodenal lumen acting at the milk lipid globule surface. This lipolysis of triacylglycerol would produce amphiphilic lipids which may result in the electron lucent spaces at the milk lipid globule periphery. The absorptive epithelial cells along the length of the duodenal villus varied in structure relative to their position at the tip, middle, or base of the villus. Typical mid‐villus epithelial cells contained lipid droplets averaging 0.3‐μm diameter in the smooth and rough endoplasmic reticulum and in Golgi complexes in the apical cytoplasm. Villus tip and villus base cells contained large lipid droplets between 7–16 μm. Only a few 0.3‐μm lipid droplets were present within these cells. These large lipid droplets appeared to be accumulations of triacylglycerol present in the apical cytoplasm associated with lamellar and membranous structures. Numerous chylomicrons were present between epithelial cells located in the middle region of the villus while significantly fewer chylomicrons were seen between epithelial cells at the tip and base of the villus. These observations suggest that the cells at the middle of the duodenal villus of suckling rats were more efficient in the production of chylomicron triacylglycerol derived from incoming milk triacylglycerol than cells at the tip and base of the villus.
Ultrastructural changes in Leydig cells of streptozotocininduced diabetic rats
Authors: Orth Joanne M. , Murray Frederick T. , Bardin C. Wayne 
Published: February 2005

AbstractHyperglycemia (experimental diabetes) was induced in adult male rats by destruction of the pancreatic beta cells with a single intravenous injection of streptozotocin (STZ). Testes from diabetic, from insulin‐treated diabetic, and from sham‐injected normal rats were fixed by vascular perfusion. The fine structure of Leydig cells was examined at two, three, and four weeks after the STZ injection in the untreated diabetic animals, and at four weeks in the controls and insulin‐treated diabetic rats. A number of morphological changes was observed in Leydig cells of untreated diabetic animals. Most obvious of these was an accumulation of lipid droplets, not normally present in Leydig cells in adults of this species. Smooth endoplasmic reticulum (SER) was markedly reduced in Leydig cells of the hyperglycemic rats. Several types of intracellular bodies were seen exclusively in Leydig cells of the untreated diabetic animals. Many resembled secondary lysosomes or dense bodies, while others appeared to be autophagic vacuoles. In addition, a small, granule‐containing lamellar structure was seen either within a typical dense body or free in the cytoplasm. Myelin‐like structures were commonly observed within the cytoplasm of the Leydig cell or within mitochondria. The appearance of the mitochondria in diabetic rats was otherwise normal. The extracellular spaces surrounding Leydig cells from untreated hyperglycemic rats also contained large accumulations of myelin‐like material. These structural changes appear to be direct consequences of the diabetic state of the animals, since the ultrastructure of insulin‐treated diabetic rats did not differ from that of the controls. These findings may reflect an alteration or breakdown of Leydig cell components normally involved in the synthesis of androgen, and correlate with previous reports of lowered circulating levels of testosterone in diabetic rats.
Regeneration of acini in submandibular gland autografts
Authors: Sharawy Mohamed , O'Dell Norris L. 
Published: February 2005

AbstractRegeneration of submandibular gland (SMG) secretory parenchyma is remarkably impaired in salivary gland diseases and under experimental conditions such as in tissue culture and after isografting. In our study acinar regeneration was found to depend on the site where the SMG tissue was implanted. Implantation of several 2–3 mm3 fragments of SMG subcutaneously in the back of the same donor adult male rat resulted in initial necrosis and mononuclear cell infiltration of the autograft. Then there was epithelial proliferation with the appearance within 28 days of lobules which contained numerous duct‐like structures and only a few or no acini. In contrast, implanting SMG fragments in the anatomical bed of the donor gland resulted in the appearance of a more differentiated autograft. Although the initial tissue changes were similar to those seen in the autografts in the subcutaneous tissues of the back, the SMG autograft in the neck also contained numerous acini by 42 and 56 days after implantation. These data support the view that the implantation site influences the course of cytodifferentiation in SMG autografts.
Distribution of taste buds on fungiform and circumvallate papillae of bovine tongue
Authors: Davies Richard O. , Kare Morley R. , Cagan Robert H. 
Published: February 2005

AbstractThe distribution of taste buds on the fungiform and circumvallate papillae of the cow tongue has been determined. The two tongues studied were from Holstein‐Friesian cows four to six years of age; they contained 14,765 and 21,691 taste buds, respectively. The tip of the tongue is well supplied with fungiform papillae, and the posterior portion contains the circumval‐late papillae. The midportion of the tongue contains relatively few taste papillae.The fungiform papillae contained 1,580 and 1,838 taste buds on the two tongues, respectively, and the circumvallate papillae were estimated to contain 13,185 and 19,853 taste buds. The highest concentration of taste buds therefore occurs in the circumvallate papillae; these relatively few papillae contain approximately 90% of the taste buds. On a circumvallate papilla, taste buds are found only on the papillary sidewall, with none either on the apical surface of the papilla or on the outer wall of the moat.
Fiber size distribution in the flexor carpi radialis muscle of the cat
Authors: Gonyea William J. 
Published: February 2005

AbstractThe pennate flexor carpi radialis muscle of the cat has been shown to have a compartmentalized distribution of muscle fiber types. The possibility exists that the oxidative regions of the FCR are primarily concerned with fine movements including postural adjustments, while fast‐twitch glycolytic region is used more for phasic movements. Muscle fiber diameters were measured for all three fiber types to determine if there was a compartmentalization of fiber size that might reflect differences in motor performance between the different regions of the same muscle. This study has demonstrated that the oxidative fiber types are significantly larger in the oxidative compartment when compared with the same fiber types in the glycolytic compartment and that the cross‐sectional area of the oxidative region is dominated by oxidative fibers. The glycolytic fibers are significantly larger in the glycolytic compartment when compared to those in the oxidative region of the muscle and they constitute the major fiber type in this region.
A study of the effect of pregnancy on muscle fibers of the rectus abdominis muscle of the rat
Authors: Martin William D. 
Published: February 2005

AbstractSamples of the rectus abdominis muscle were taken from Sprague‐Dawley rats at 0, 3, 6, 9, 12, 15, 18, and 21 days of pregnancy, and at 1, 3, 6, 9, 12, and 15 days of postpartum. Sections were incubated for actomyosin adenosine triphosphatase activity following preincubation at a basic pH. Muscle fibers within a unit area of each sample were identified as to fiber type according to their enzyme activity, and the population of each type counted. The proportion of each fiber type was calculated and the diameter of 24 fibers of each type measured. No changes were noted in the muscle fiber proportions through the course of the experiment. Differential changes in muscle fiber diameters were noted in each of the three muscle fiber types. Slow oxidative fibers underwent an increase in diameter through the last half of pregnancy. The diameter was further increased as stretch of the muscle was released after birth, and did not decrease in the postpartum period. Fast glycolytic fibers decreased in diameter during the last half of pregnancy, but returned to the prepregnancy diameter in the first postpartum day. The diameter of the fast oxidative glycolytic fibers remained unchanged through the course of pregnancy and in the postpartum period.
Anatomic Models of the tracheobronchial and pulmonary regions of the rat
Authors: Yeh H. C. , Schum G. M. , Duggan M. T. 
Published: February 2005

AbstractModels of the lung airways of a rat were developed from complete measurements of the tracheobronchial airways. A silicone rubber cast of the tracheobronchial airways of a rat lung was prepared and all individual airway segments down to and including the terminal bronchioles were measured to obtain the segment diameters, lengths, branching angles and angles of inclination to gravity. Models of the rat tracheobronchial airways were constructed based on the original measurements and the subsequent analysis. Some mathematical assumptions about acinar anatomy distal to terminal bronchioles were made to extend the models to include pulmonary regions. Emphasis was placed on the “Typical Path Lung Model” which used one typical pathway to represent either a whole lung or a lobe of the lung. The models are simple and can be applied in calculation of physiologic variables or particle deposition during inhalation in various lobes of the lung.
Electron microscopic observations on the yolk sac of the Indian fruit bat, Rousettus leschenaulti (Desmarest) (Pteropidae)
Authors: Karim K. B. , Wimsatt W. A. , Enders A. C. , Gopalakrishna A. 
Published: February 2005

AbstractThe yolk sac of the Indian fruit bat Rousettus leschenaulti is unique since during the course of development it become converted into a solid, richly vascular endocrine gland‐like structure with both the endodermal and mesothelial cells undergoing substantial hypertrophy. The yolk sac is progressively drawn from the abembryonic (antimesometrial side) to the embryonic pole (mesometrial side) of the chorionic sac where in late stages it comes to rest against the placental disc. The endodermal cells become grouped into clusters of acinus‐like structures surrounded by the columnar mesothelial cells; the yolk‐sac lumen is in most instances obliterated. Individual endodermal cells are large in comparison to mesothelial cells. The endodermal cell population varies between cells with abundant agranular ER and areas devoid of organelles to others with dense cytoplasm containing stacks of granular ER. All endodermal cells have numerous mitochondria and a few lipid droplets.The mesothelial cells are columnar with either dome‐shaped, pointed or flattened apices bearing numerous elongate microvilli; within these are parallel‐arranged microfilaments. While the apical cytoplasm shows the presence of absorptive tubules. coated vesicles and caveolae, the basal cytoplasm contains a few small mitochondria. Some mesothelial cells contain lipid droplets in their basal cytoplasm. On structural bases it is postulated that the mesothelial cells are absorptive in function while the endodermal cells are synthetic and secretory.
A Morphometric analysis of the glomerular capillary wall of a new strain of genetically hypertensive mice
Authors: Rosenberg Warren , Schlager Gunther , Gennaro Joseph F. 
Published: February 2005

AbstractAn investigation was performed on a new strain of genetically hypertensive mice to study those aspects of the renal glomerulus which have in the past been implicated in the etiology of renal parenchymal hypertension. Morphometric analyses were carried out utilizing a computerized graphic data analysing system on information obtained through transmission electron microscopy. Chronically hypertensive animals exhibited thinner basement membranes with numerous sub‐epithelial focal thickenings, which were largely absent from the normotensive controls. No difference was noted in the width of the epithelial slit pores (interpedicelar spaces). The glomerular capillary loops of the hypertensive animals appeared otherwise unremarkable, as did the urinary space and parietal epithelium of Bowman's capsule. No evidence of renal parenchymal pathologies implicated in the etiology of systemic hypertension was observed, therefore, these animals would seem to be suitable models for human essential hypertension.
Variations in the aortic origin of intercostal arteries in man
Authors: Khan Sabiha , Haust M. Daria 
Published: February 2005

AbstractThe variation in the origin of the (posterior) intercostal arteries was examined in 79 aortae of children who ranged in age from 1 day to 15 years and died of various causes. The distribution, size and number of the origins of the (usually present: 9) pairs of these arteries varied widely. The most commonly observed patterns were as follows: variation in distance between arteries of a given pair; variation in spacing between adjacent pairs; presence of a supernumerary single artery or of a pair; absence of one or both arteries of a given pair; unequal size of the orifices of a pair; complete division of a single artery into two branches beyond its origin; and an incomplete division of a single artery by a partial septum.Of interest appears to be the absence of one (in 59 instances) or both (in 17 instances) arteries of the same pair; the tenth intercostals were most commonly so affected. It would require a prospectively designed study to ascertain whether the absence of any of the intercostal arteries may have a clinical effect in man. Since these arteries supply directly or indirectly not only the intercostal and pectoral muscles, serratus anterior and the muscles of the back, but also the spinal cord, and in addition, provide cutaneous and a few mammary branches, functional correlations in the absence of given arteries may prove to havepractical implications.
Morphologic features of the caudal neurosecretory system in the blueback herring, Pomolobus aestivalis
Authors: Kriebel Richard M. , Burke Jack D. , Meetz Gerald D. 
Published: February 2005

AbstractThe caudal neurosecretory system of the blueback herring, Pomolobus aestivalis, captured in freshwater, was examined. Neurosecretory cells were identified readily in terminal spinal cord segments. The axonal processes of these neurosecretory cells formed a discrete, ventrally placed bundle which terminated in a conspicuous ventral enlargement from the filum terminale. This enlargement comprises the neurohaemal contact zone or urophysis. The neurosecretory terminals were engorged with secretory granules in these fishes from a freshwater environment.The non‐neuronal component of the urophysis also was examined in this study. These glial cells were dispersed throughout the urophysis. Most often they were found ensheathing the terminal neurosecretory processes. These cells showed a resemblance to neurohypophysial pituicytes. Although mentioned in the literature, these glial cells have not been examined with the electron microscope. The ultrastructural features of the glial cells and their relation to the neurosecretory constituents are described in this report.