bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extraocular muscles in the microphthalmic rat
Authors: Tanaka Koichi , Otani Katsumi , Sugita Shoei 
Published: February 2005

AbstractThe extraocular muscles in a mutant microphthalmic strain of rat were studied. The eyeball of this strain of rat is reduced to about a third in diameter of that of the normal rat. Nevertheless, in the orbit of the mutant rat, every one of the extraocular muscles was identified; their origins and courses were the same as in the normal rat, but differences existed in the insertions. These insertions could be classified into three groups: Group A (retractor bulbi): like normal insertion into the eyeball. Group B (superior rectus and superior oblique): attachment of tendonlike insertions to each other; these muscles come from opposite directions and form a loop. Group C (lateral, medial, and inferior rectus and inferior oblique): insertion into connective tissue surrounding the reduced eyeball.The volume of each muscle of the mutant rat was smaller than that of the normal rat; moreover, significant differences existed in the degree of reduction in the volume of each muscle group classified according to the change of insertion. In the group A muscle the volume was only 33% of the normal volume, whereas group B was 74% and group C was about half of normal.
Isoflurane as an anesthetic for experimental animal surgery
Authors: Raper Steven E. , Barker Mary E. , Burwen Susan J. , Jones Albert L. 
Published: February 2005

AbstractIsoflurane is an inhalational anesthetic agent associated with no known hepatic toxicity. Despite this fact, isoflurane has not been widely utilized as an anesthetic agent in studies of liver structure and function in experimental animals. For this reason, livers from rats treated with pentobarbital or diethylether were compared to those from rats treated with isoflurane to determine differences in biochemical and morphologic parameters.Liver from pentobarbital‐treated rats showed a significant decline in glutathione‐S‐transferase activity compared to liver from isoflurane/O2 or ether‐treated rats. Liver microsomes from isoflurane/O2‐treated rats retained more cytochrome‐C(P450)‐reductase activity than did those from pentobarbital‐treated, ether‐treated, or decapitated rats. Despite these biochemical alterations, morphometric analysis of liver from isoflurane/O2 and pentobarbital‐treated rats showed no quantitative or qualitative differences in liver structure or organelle volume densities. Neither were differences detected in uptake and distribution of 125I‐epidermal growth factor when analyzed by electron microscopic autoradiography. These data show that isoflurane with supplemental O2 has no effects on hepatic structure and fewer effects on hepatic function than other anesthetics and may be a better experimental anesthetic than any currently in use.
Fiber‐type composition of selected hindlimb muscles of a primate (cynomolgus monkey)
Authors: Acosta Luis , Roy Roland R. 
Published: February 2005

AbstractThe distribution of fiber types in selected leg and thigh muscles of three male Cynomolgus monkeys were determined. Almost all fibers could be classified as fast‐glycolytic (FG), fast‐oxidative glycolytic (FOG), or slow‐oxidative (SO) according to the qualitative histochemical staining scheme described by Peter et al. (1972). Most muscles showed regional variations in fiber‐type distributions, i.e., the percent SO was higher and the percent FG was lower in the deep, compared to the superficial, regions of the muscle. Exceptions were the soleus and plantaris muscles, which contained similar distributions of fiber types throughout their cross sections. In the extensor compartment of the leg, a layering of fiber types from deep to superficial were evident in the triceps surae and plantaris complex with the deepest muscle, the soleus, having primarily SO fibers. A similar layering arrangement was observed in the extensor compartment of the thigh, with the deepest muscle, the vastus intermedius, having a much larger proportion of SO fibers than the other muscles in the quadriceps complex. These results indicate that Cynomolgus monkey hindlimb muscles, unlike human leg muscles (Saltin and Gollnick: Handbook of Physiology, L.D. Peachey, ed. American Physiological Society, MD, pp. 55–631, 1983) have a regional distribution of fiber types similar to that observed in many subprimate mammals. Further, the presence of compartmentalization of fiber types within the cross section of several of the muscles studied is suggestive of structure‐function interrelationships related to motor control.
Effects of salt loading on the fractional volume of atria‐specific granules in dahl salt‐sensitive and salt‐resistant rats
Authors: Hansen John T. , Haywood J. R. , Howell Andrew 
Published: February 2005

AbstractThe cardiac atria are known to play a role in blood volume homeostasis, secreting a peptide that induces a potent natriuresis and diuresis. This peptide is atrial natriuretic factor (ANF), and its primary site of storage is within atria‐specific granules found in atrial cardiocytes.Since salt loading results in an increase in circulating levels of ANF, our aim was to determine if the atria‐specific granule population in the cardiocytes of Dahl rats would decrease accordingly. To this end, the fractional volume of the atria‐specific granules was determined by ultrastructural morphometric analysis in the Dahl salt model of hypertension. This analysis was performed on the right atria of Dahl salt‐resistant (DR) and salt‐sensitive (DS) rats fed either a low‐salt (0.4%) or high‐salt (8%) diet for 12 weeks prior to sacrifice. DR and DS rats fed a low‐salt diet had significantly reduced plasma sodium levels and osmolalities, and a significantly lower mean arterial blood pressure than did rats fed a high‐salt diet. The fractional volume of atria‐specific granules was significantly lower in salt‐loaded DR (P<0.01) and DS (P<0.025) rats than in their respective low‐salt controls. This significant decrease in atrial granules corresponds to the reported decrease in the storage of atrial ANF in salt‐loaded rats, and provides a morphological verification of the biochemical studies. Moreover, these results, in combination with a growing body of physiological data, lend support to the hypothesized role of ANF in the regulation of water–electrolyte balance, which may play an important role in cardiovascular pathophysiological states related to hypertension.
Postnatal development of the vallate papilla and taste buds in rats
Authors: Hosley Mark A. , Oakley Bruce 
Published: February 2005

AbstractThe postnatal maturation of the vallate papilla and its taste buds was quantitatively investigated in rats by light microscopy. Specifically, we measured postnatal increases in the size of mature vallate taste buds and the vallate papilla, increases in the thickness of the gustatory epidermis, and increases in the number of mature taste buds and taste cells per bud. Mature taste buds, defined as those having a taste pore, are rare at birth but proliferate rapidly during the first postnatal month until an average of 610 mature taste buds has accumulated by 90 days. Throughout this postnatal period, mature taste buds adjust to the developmental thickening of the epidermis by continuously increasing in length. Mature taste buds also increase in width, in part due to a threefold increase from 10 and 45 days in the number of taste cells per bud. From 10 to 21 days there is an average daily net increase of three cells per mature taste bud. The maturational increase in taste buds and cells may contribute to the functional changes in taste nerve responses known to occur over the course of several generations of taste receptor cells. The dimensions of the vallate papilla and the surface area of the gustatory epithelium increase logarithmically with age. Although mature taste buds continue to increase in number until 90 days, both taste bud density (178/mm2) and the number of cells per mature taste bud (70–75 cells) reach ceilings by 45 days. Thus, density‐dependent factors appear to control vallate taste bud maturation. The immaturity of lingual taste buds in newborn rats supports the view that odor, rather than taste, is the chemosensory signal that guides suckling in altricial rodents.
Differences in glycocalyx composition between cells of the cortical thick ascending limb of Henle and the macula densa revealed by lectin‐gold cytochemistry
Authors: Rielle Jean‐Charles , Brown Dennis , Orci Lelio 
Published: February 2005

AbstractThe glycocalyx composition of cells from the macula densa and the cortical thick ascending limb of Henle was examined in rabbit kidney by means of the lectin‐gold technique. A quantitative evaluation at the ultrastructural level showed that macula densa cells had a considerably greater affinity for Helix pomatia lectin than adjacent cells of the thick ascending limb. Wheat germ lectin and concanavalin A bound equally well to both cell types. This difference in plasma membrane glycocalyx composition may be an important aspect of the functional differentiation of cell types in this specialized nephron segment.
Intramembrane aspects of myotendinous and myomuscular junctions: A freeze‐fracture study of the gill sac‐muscle of the atlantic hagfish, Myxine glutinosa
Authors: Bartels Helmut 
Published: February 2005

AbstractThe intramembrane organization of the sarcolemma at the sites of myotendinous and myomuscular junctions was studied in the gill sac‐muscle of the Atlantic hagfish, Myxine glutinosa, by using freeze‐fracture replicas. At these sites rows of irregularly shaped particles (diameter approximately 6 nm) and short fibrils are present on the P face and a complementary pattern of grooves is present on the E face of the split plasma membrane. The center‐to‐center distance between adjacent rows of particles and grooves ranges from 12 to 20 nm. Rodlike projections being in register with the rows of particles and grooves, respectively, extend from the plasma membrane toward the extracellular space. These rodlike projections are also recognizable in thin sections, where they appear as spinelike projections (cross sections) or linear arrays (grazing sections) located in the lamina lucida of the basal lamina.The intramembrane particles are considered to be integral membrane proteins and to represent transmembrane links in a series of molecules by which intracellular actin filaments and extracellular collagen fibrils are connected across the plasma membrane. The rodlike projections are probably peripheral membrane proteins possibly connecting the plasma membrane with structural components of the basal lamina.
A stereological comparison of the muscle‐tendon junctions of fast and slow fibers in the chicken
Authors: Trotter J. A. , Baca J. M. 
Published: February 2005

AbstractTransmission of contractile tension from skeletal muscle fibers to connective tissue elements is thought to occur at the muscle–tendon junctions, specialized regions at the extreme ends of the fibers. Previous work has suggested that the structure of this region may be quantitatively modified to match the contractile properties of the fibers. Using scanning electron microscopy, transmission electron microscopy, and stereological analysis, we have analyzed the three‐dimensional structure, and have quantitatively compared the muscle–tendon junctions, of slow and fast fibers of the anterior (ALD) and posterior (PLD) latissimus dorsi muscles of the chicken. The ends of ALD and PLD fibers are found to be structurally different in some respects but to be similar with respect to their surface specializations, which are believed to function in the transmission of tension. Quantitative analysis of these specializations indicates that, when referred to similar cross‐sectional areas of myofilaments, the fast fibers of the PLD have approximately 40% more surface area devoted to force transmission than do the slow fibers of the ALD. These observations are consistent with the idea that the amount of cell surface specialized for force transmission is related to the functional properties of the muscle fiber.
Three‐dimensional architecture of sarcoplasmic reticulum and T‐system in human skeletal muscle
Authors: Hayashi Kazuko , Miller Rodman G. , Brownell A. Keith W. 
Published: February 2005

AbstractA modified Golgi method combined with stereoscopy has been used to demonstrate the three‐dimensional architecture of the sarcoplasmic reticulum (SR) and the T‐system in human skeletal muscle. SR formed a continuous repeating network with a different structure dependent upon the sarcomere position. Intermyofibrillar SR contained three regions: 1) fenestrated collars overlying the M‐band region, 2) terminal cisternae overlying the A‐I region, and 3) a three‐dimensional anastomosed tubular network overlying the Z‐band region. Longitudinal and/or transverse SR tubules connected these regions. Subsarcolemmal SR was also composed of three regions: 1) transversely oriented polygonal meshes overlying the M‐band, 2) single‐layered tubules overlying the Z‐band region, and 3) a loose network between the two. In the subsarcolemmal sarcoplasm, where mitochondria were aggregated, SR anastomosed loosely and showed nonfenestrated cisternae beneath the plasma membrane. The T‐system was composed of transversely oriented networks overlying the A‐I region with occasional longitudinal tubules connecting these networks.
Endocytic activity of Sertoli cells grown in bicameral culture chambers
Authors: Rong‐Xi Dai , Djakiew Daniel , Dym Martin 
Published: February 2005

AbstractImmature rat Sertoli cells were cultured for 7 to 14 days on Millipore filters impregnated with a reconstituted basement membrane extract in dualenvironment (bicameral) culture chambers. Electron microscopy of the cultured cells revealed the presence of rod‐shaped mitochondria, Golgi apparatus, rough endoplasmic reticulum, and Sertoli‐Sertoli tight junctions, typical of these cells in vivo. The endocytic activity of both the apical and basal surfaces of the Sertoli cells was examined by either adding alpha2‐macroglobulin (alpha2‐M) conjugated to 20 nm gold particles to the apical chamber or by adding 125I labeled alpha2‐M to the basal chamber. During endocytosis from the apical surface of Sertoli cells, the alpha2‐M‐gold particles were bound initially to coated pits and then internalized into coated vesicles within 5 minutes. After 10 minutes, the alpha2‐M‐gold was found in multivesicular bodies (MVBs) and by 30 minutes it was present in the lysosomes. The proportion of alpha2‐M‐gold found within endocytic cell organelles after 1 hour of uptake was used to estimate the approximate time that this ligand spent in each type of organelle. The alpha2‐M‐gold was present in coated pits, coated vesicles, multivesicular bodies, and lysosomes for approximately 3, 11, 22, and 24 minutes, respectively. This indicates that the initial stages of endocytosis are rapid, whereas MVBs and lysosomes are relatively long‐lived. Since alpha2‐M‐gold was unable to permeate from the basal chamber through the Millipore filter to Sertoli cells, the uptake of alpha2‐M from the basal cytoplasm of Sertoli cells was studied using 125I‐alpha2‐M. After 2 hours incubation, approximately 1.7% of the added 125I‐alpha2‐M was taken up specifically by the basal cytoplasm of the Sertoli cells. Both alpha2‐M‐gold and 125I‐alpha2‐M could be displaced by increasing concentrations of unlabeled alpha2‐M. This indicates that alpha2‐macroglobulin was internalized by a receptor‐mediated endocytic process both from the apical surface and the basal surface of confluent epithelial sheets of Sertoli cells grown in bicameral culture chambers.
Accumulation and distribution of sulfated materials in the maturing mouse lens capsule
Authors: Webster E. H. , Searls R. L. , Hilfer S. R. , Zwaan J. 
Published: February 2005

AbstractLenses of late gestational and postnatal normal‐eyed mice were tested for accumulated sulfated materials by using Spicer's high‐iron‐diamine staining method and also for newly incorporated sulfate autoradiographically following adminsitration of 35SO4 either in vivo or in isolated and organ‐cultured lenses. Accumulated and newly incorporated sulfate was observed in all lenses for each age group tested. Discrete regional differences were seen in histochemical staining patterns for sulfate on the lens capsule in specimens of all ages, and distinct laminar zonations were seen in the various regions of the capsule in older specimens. Typically, the anterior and equatorial regions of the capsule demonstrated three histochemically distinct laminar zones while the posterior capsule usually demonstrated two laminar zones. Autoradiographic results indicated that sulfate was indeed being incorporated into these regions, and in the same general pattern as seen with histochemistry. The materials were largely insensitive to testicular hyaluronidase but were preferentially sensitive to nitrous acid digestion, indicating the presence of capsular heparan sulfates. Autoradiographic results from organ‐cultured lenses indicated that this tissue itself is a primary source of these materials.
Morphology of the carotid sinus wall in normotensive and spontaneously hypertensive rats
Authors: Hansen John T. 
Published: February 2005

AbstractThe morphology of the carotid sinus region of the internal carotid artery was studied in spontaneously hypertensive rats (SHR) at 5, 8, 16, and 24 weeks of age. The carotid sinus region occupied the proximal millimeter of the internal artery, and was easily recognizable by the presence of an extensive adventitial capillary plexus, which was absent on adjacent arteries (e.g., common and external carotid arteries). Methylene blue‐stained whole‐mount preparations showed the extent of baroreceptor nerves over the sinus. Baroreceptor fibers terminated in distinctive bulbous‐like endings, which, at the ultrastructural level, were filled with mitochondria. No differences were noted in the sinus adventitial capillary network or baroreceptor distribution between SHR and age‐matched Wistar‐Kyoto (WKY) normotensive control animals. With the onset of a significant rise in SHR blood pressure, the carotid sinus wall increased in thickness and total vessel size. The wall/lumen ratios were significantly larger in the SHR than in age‐matched WKY ratios in all age groups. SHR carotid sinus vessel enlargement was uniform throughout the vessel tunics, with no significant change in the proportion of the tunica media occupied by smooth muscle cells. The increase in the carotid sinus wall thickness associated with increasing hypertension could affect the ability of the sinus to distend and may play a secondary role in the maintenance of hypertension by compromising baroreceptor nerve ending sensitivity.
Pericytes in human cerebral microvasculature
Authors: Farrell C. R. , Stewart P. A. , Farrell C. L. , Del Maestro R. F. 
Published: February 2005

AbstractTwo classes of pericytes are thought to exist in cerebral microvasculature, granular and agranular. This classification is based on the presence or absence of cytoplasmic, lysosome‐like granules of variable size and appearance. The pericytes in structurally normal human brain tissue from 17 patients, male and female, ranging in age from 14 to 77, were examined. Light microscopic examination of single sections revealed that 67% of pericyte profiles contained granules in both sexes, and this ratio did not change with age. Following the serial reconstructions of 80 individual pericytes, it was found that all contained characteristic cytoplasmic granules. These data show that if truly agranular pericytes do exist in human cerebral microvasculature, they must constitute less than 5% of the population.
Significance of increase in glucose 6‐phosphatase activity in brown adipose cells of cold‐exposed and starved mice
Authors: Watanabe Jun , Kanamura Shinsuke , Tokunaga Hirohiko , Sakaida Minoru , Kanai Kazuo 
Published: February 2005

AbstractCytochemical and biochemical glucose 6‐phosphatase (G6Pase) activity was examined in brown adipose tissues of normal, cold‐exposed, or starved mice. In addition, G6Pase activity in white adipose tissue and hexokinase activity in brown and white adipose tissues were biochemically measured. In normal animals, the reaction product for G6Pase activity was localized in the endoplasmic reticulum and nuclear envelope of brown adipose cells. The amount of the reaction product increased in cold‐exposed or starved animals. Biochemical G6Pase activity (259.7 ± 48.5 ng Pi/min/mg protein) in brown adipose tissues of normal animals was higher when the value was compared with values of other organs. Biochemical G6Pase and hexokinase activities increased rapidly in brown adipose tissues of cold‐exposed animals, and a close relation was found between activities of the two enzymes. In brown adipose tissues of animals starved for 3 days, biochemical G6Pase activity increased, but hexokinase activity did not change. In white adipose tissues of normal, cold‐exposed, or starved animals, G6Pase activity was very low, although the enzyme activity increased slightly in animals starved for 3 days. The results show that the high G6Pase activity in brown adipose cells probably relates to thermogenesis in cold‐exposed animals and may be concerned with glucose release into the blood in starved animals.
Segmental variations in the elastic fiber content of the lateral costotransverse ligaments in the vervet monkey (Cercopithecus pygerythrus aethiops)
Authors: Kimani James Kirumbi , Walji Anil H. , Mungai Joseph M. 
Published: February 2005

AbstractThe segmental and zonal variations in the quantitative relationships between elastic and collagen fibers within the lateral costotransverse ligaments have been investigated in the vervet monkey. The lateral costotransverse ligaments of the caudal segments have a largely elastic structure in contrast to those of the cranial segments, which are characteristically collagenous. In the transitional zone extending from the 4th through to the 6th costotransverse joints, the lateral costotransverse ligaments show a zonal differentiation into a superficial collagenous portion and a deep elastic portion. It is noted that the craniocaudal structural differentiation in the lateral costotransverse ligaments corresponds with similar changes in the vertebral ligaments in that the ligamenta flava gradually extend into the interspinous spaces from the 1st thoracic vertebra (T1) so that at T5 the ligaments occupy 50% of the interspinous space and at T7 the elastic fibers almost completely replace the interspinous ligament. Functionally, however, the regional differences in the elastic fiber content of the lateral costotransverse ligament may have no collateral relationship with the morphology of the ligamenta flava, but are conditioned by movements of the ribs. Whereas movements of the upper six joints are limited by virtue of the configuration of their articular surfaces, which are reciprocally curved, on the 7th to 10th joints the articular facets are almost flat and, therefore, allow considerable movements between the ribs and the corresponding transverse processes.