bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional anatomy of the major cardiac nerves in cats
Authors: Phillips John G. , Randall Walter C. , Armour J. Andrew
Published: February 2005

In recognition of the extensive use of the cat as an experimental model of cardiac innervation, the effects of electrical stimulation of stellate ganglia, thoracic vagosympathetic complexes, and individual feline cardiopulmonary nerves on heart rate, blood pressure, and contractility in all four cardiac chambers were analysed and correlated with the anatomy of the thoracic autonomic nervous system. The right and left stellate ganglia in cats are relatively large and globular. Distinct dorsal and ventral ansae subclavia arise from these ganglia, connecting with the relatively small, spindle‐shaped middle cervical ganglia situated in the apices of the thoracic cage bilaterally. A cranial pole nerve arises from each of the middle cervical ganglia and courses cranially to unite with the ipsilateral superior cervical ganglia. On each side, the major cardiopulmonary nerves arise from the middle cervical ganglion, the relatively large vagosympathetic trunk, and the stellate ganglion. On the right side these nerves consist of a very small right stellate cardiac nerve, a recurrent cardiac nerve, a group of craniovagal nerves and a group of caudovagal cardiopulmonary nerves. On the left side are the left stellate cardiac, ventrolateral, ventromedial, and innominate cardiopulmonary nerves. All of these nerves contain efferent parasympathetic and/or sympathetic fibers which modify cardiac chronotropism and/or inotropism. Some contain afferent fibers. These results indicate that specific cardiopulmonary nerves exist in cats, which when stimulated, modify the cardiovascular system in specific fashions.
Localized vascular regression during limb morphogenesis in the chicken embryo: II. Morphological changes in the vasculature
Authors: Latker Carole H. , Feinberg Richard N. , Beebe David C.
Published: February 2005

The regression of blood vessels in the distal wing bud of chicken embryos from stages 19 to 31 was examined by light and electron microscopy. The vessels were double‐labelled by an injection of Monastral blue B (MB) to label the regressing endothelial cells, followed 6–48 hours later with an injection of India ink which marked the lumens of patent vessels. Prior to stage 26 the vessels contained only India ink since the endothelial cells were not phagocytic at this stage. Vessels at stage 26 or later were often double‐labelled, with MB sequestered in the endothelial cell cytoplasm and India ink in the vessel lumens. After stage 27 cells not associated with lumens, but labelled with MB, were observed in areas undergoing vascular regression. Ultrastructural changes in the endothelial cells as the vessels regressed included formation of luminal and abluminal processes, long complex junctions, and vacuoles containing MB. In many involuting vessels the endothelial cells appeared normal even though the lumens were collapsed. Occasionally, isolated pyknotic cells were observed in regions that had been previously vascularized. At stage 31 cells in the developing cartilage had vacuoles containing MB. Our study suggests that blood vessels may disappear from the prechondrogenic zone of the distal wing bud by several mechanisms. These could include a type of cell death that does not elicit a cellular infiltrate, migration of the endothelial cells away from vascularized regions, and/or transdifferentiation into cells that resembled chondrocytes.
Convergence of sensory processes from the heart and left ulnar nerve onto a single afferent perikaryon: A neuroanatomical study in the rat employing fluorescent tracers
Authors: McNeill Daniel L. , Burden Hubert W.
Published: February 2005

After injection of true blue (TB) into the pericardial sac and nuclear yellow (NY) into the left ulnar nerve of rats, most perikarya in the left eighth cervical and first thoracic dorsal root ganglia are single‐labeled with either TB or NY. However, 7.1–14.7% of the sensory perikarya from the cardiac area labeled with TB are simultaneously labeled with NY. This finding indicates that some primary sensory perikarya receive processes from both the left arm and the heart. In addition to other mechanisms that may be operative in the referral of pain of cardiac origin to the medial left arm, these results suggest that sensory neurons with dichotomizing somatic and visceral peripheral processes may also contribute to this phenomenon.
Light and electron microscope demonstration of VIP‐ and enkephalin‐immunoreactive nerves in the human male genitourinary tract
Authors: Vaalasti Annikki , Tainio Hanna , Pelto‐Huikko Markku , Hervonen Antti
Published: February 2005

Vasoactive intestinal polypeptide (VIP) and enkephalins were demonstrated in the nerves of the human male urogenital tract by light and electron microscope immunohistochemical techniques. Nerves containing immunoreactivity to VIP were more numerous than enkephalin‐immunoreactive nerves. Both VIP‐and enkephalin‐immunoreactive nerves were detected in the vas deferens, prostate, seminal vesicles, and urinary bladder. In the kidney, testis, and epididymis no immunoreactive nerves could be demonstrated. By electron microscope both types of immunoreactivities were localized to the large granular vesicles of nerve terminals. VIP‐immunoreactive nerves were mostly found subepithelially, whereas enkephalin‐immunoreactive nerves were mainly related to smooth muscle cells. The possible functions of these peptide‐containing nerves are discussed.
A hypothesis on the allantoic origin of the distal midgut
Authors: Zarabi C. M. , Rupani Mahendra
Published: February 2005

No satisfactory explanation for the absence of the ileocecal portion of the digestive system in the newborns with cloacal exstrophy has been offered previously. This is a report of such a case in which the lymphocytes and plasma cells were used as tissue markers to identify the origin of the lymphatic‐rich ileocecal portion of the digestive tract. The absence of these cells, in this case demonstrated immunohistochemically, is suggestive of a dual origin of the midgut. Normal embryogenesis of the digestive system is reviewed and the possibility of participation of the allantois, in addition to the yolk sac, in the embryogenesis of the ileocecal segment of the gastrointestinal tract is discussed.
Freeze‐fracture analysis of intramembrane particles of erythrocytes from normal and dystrophic hamsters
Authors: Davis Elaine C. , Shivers Richard R.
Published: February 2005

The intramembrane particles on plasma membranes of erythrocytes of Syrian hamsters afflicted with hereditary muscular dystrophy were compared to those from normal controls by freeze‐fracture analysis. The reduced number of particles in both fracture faces of dystrophic erythrocyte plasmalemmae, as compared to that of control red cells, was found to be highly significant (P =.001). Results of this study therefore, support the concept of a generalized membrane defect (abnormality) in muscular dystrophy.
Pattern and distribution of intrahepatic lymph vessels in the rat
Authors: Niiro George K. , O'Morchoe Charles C. C.
Published: February 2005

The pattern and distribution of intrahepatic lymph vessels were examined by light and electron microscopy in rat livers fixed by perfusion through the portal vein. Lymph vessels were found in the connective tissue of the larger portal canals, where they coursed in close association with branches of the hepatic artery. The smallest portal canals contained no lymphatics. Of the portal canals that lacked a lymphatic, over 50% also lacked an arterial component. Direct connections between the lymphatic lumen and the spaces of Disse or Mall were not observed but lymphatics were found close to Mall's space, separated by only a sparse connective tissue space containing a few collagen fibrils. Lymphatics were neither seen within the parenchyma, nor associated with intercalated (sublobular) veins. Cross‐sectional area (223.2 ± 48.7 μm2 SEM), maximum diameter (20.5 ± 2.0 μm), volume density (0.00098 ± 0.00046 μm3/μm3) and profile density (1.8 ± 0.3 lymphatics per 1 mm2) of hepatic lymph vessels were determined by stereological measurement by a computer‐based image analyzer. These data were used to estimate the rate of lymph formation in the liver. It was concluded that (1) initial lymphatics probably originate in the portal canals; (2) the concept that fluid in the space of Disse can be regarded as the principal source of fluid‐forming hepatic lymph is questioned, since initial lymphatics appear to be separated from the space of Disse by hepatocytes and the space of Mall; and (3) the rate of lymph formation in the liver of the rat is approximately 0.06–0.08 μl/min/cm2 of lymphatic endothelium.
Differentiation and thyroid‐stimulating hormone (TSH) sensitivity of the fetal rat thyroid in organ culture
Authors: Yamamoto Masako , Takizawa Tatsuya , Arishima Kazuyoshi , Eguchi Yasunobu
Published: February 2005

Thyroids from rat fetuses of different ages (from day 14 to day 19 of gestation) were transplanted to organ culture for 2 days, with or without added thyroid‐stimulating hormone (TSH) in the medium. Thyroid tissue from 14‐day fetuses that initially consisted of irregularly arranged cell cords did not form follicles when cultured in the presence or absence of TSH. Thyroids from 15‐ and 16‐day fetuses initially consisted of epithelial cell masses. When cultured in the presence or absence of TSH they formed follicles, and a majority stored small amounts of colloid. In thyroid transplants from 17‐day fetuses, the response to TSH appeared as a significant increase in the follicular diameter and cell height. Thereafter, in all transplants cultured in the presence of TSH, both the follicular diameter and the cell height were markedly greater than in the transplants cultured in the absence of added TSH. These results suggest that the initial formation of thyroid follicles is independent of TSH and that, once developed, follicles become able to respond to TSH.
Influence of colchicine on the distribution of horseradish peroxidase in the secretory ameloblast layer in vitro
Authors: Matsuo Saburou , Yamamoto Katsuhiko , Nishikawa Shinji , Ichikawa Hiroyuki , Wakisaka Satoshi , Takano Yoshiro , Akai Michio
Published: February 2005

The distribution of exogenous horseradish peroxidase (HRP) in the secretory ameloblast layer of developing rat molar tooth germs was examined in a culture system with and without colchicine. The secretory ameloblast of cultured tooth germs engulfed HRP added to the medium regardless of the presence of colchicine. The reaction product was localized in various vesicles and granules. Without colchicine in the medium, many small vesicles containing HRP were located in the Tomes' processes, whereas only a few were present with colchicine at concentrations above 5 μM. An intense reaction of HRP also appeared in the distal extracellular spaces beyond the distal junctional complexes of ameloblasts cultured without colchicine, whereas it became almost indiscernible in the tooth germs cultured with colchicine. The lack of HRP in the Tomes' processes and distal extracellular spaces of ameloblasts treated with colchicine might be attributed to the disruption of microtubules. The present study suggests that the secretory ameloblast is able to transport tracer molecules through the intracellular pathway from the proximal and lateral extracellular spaces to the distal extracellular space.
Vascularization of the rat cornea after prolonged zinc deficiency
Authors: Leure‐Dupree Alphonse E.
Published: February 2005

Neovascularization of the anterior stroma of the rat cornea was associated with prolonged zinc deficiency (in this model). There was also an increase in the myelinated nerves of the cornea. Blood vessels were not observed in the corneas of the pair‐fed and ad‐libitum‐fed control animals. The invading blood vessels were frequently associated with Schwann cells and neurites. Unmyelinated nerves were observed in the corneal stroma of all three experimental groups.
Sorting and transepithelial transport of adsorbed protein tracers: Effects of temperature
Authors: Wilson Jean M. , King Barry F.
Published: February 2005

The epithelium of the guinea pig yolk sac is involved in the selective transport of macromolecules to the fetus. We studied the compartments involved in sorting and transepithelial transport of protein tracers and the effect of lowered temperature (18°C) on these events. Explants of yolk sac were incubated with a mixture of cationized ferritin (CF) and horseradish peroxidase (HRP, Sigma type VI). At 4°C, both tracers were bound to the cell surface and binding of an HRP‐gold complex was shown to be inhibited by mannan. At 37°C and 18°C, both tracers were taken up into tubules and vesicles in the apical cytoplasm. Usually the tubules contained a mixure of tracers, but they often showed a polarized distribution with CF and HRP at opposite ends. The vesicles also contained mixtures of the tracers, but some contained only one. In addition, there were some irregularly shaped vacuoles composed of saccules that contained either a mixture, HRP alone, or CF alone. These results suggest that these adsorbed ligands are binding to unique microdomains of the endocytic complex. After 20 min at 37°C coated vesicles 100 nm in diameter were located in the apical cytoplasm and coated vesicles of the same size were located at the lateral cell membrane. Usually they contained only HRP or CF, although occasional mixtures were seen. At 18°C, HRP was transported across the cells in 100 nm vesicles. However, transport of CF was completely inhibited at the lower temperature. Although uptake at 18°C was slower than that at 37°C, experiments with 125I‐CF allowed comparison of time points at which equal uptake had occurred. These experiments demonstrated that inhibition of CF transport was not due to decreased amounts of internalized CF. These differences in transport of HRP and CF suggest that multiple compartments are involved in the sorting and transepithelial transport of protein, and at least one is perturbed by lower temperature.
The rete ovarii of cattle and deer communicates with the uterine tube
Authors: Odend'hal Stewart , Wenzel James Guthrie Wheeler , Player Emory Craig
Published: February 2005

Textbooks in embryology, histology, and reproductive biology erroneously state that the mammalian rete ovarii consists of a tubular structure in the medulla of the ovary which is closed at both ends. In white‐tailed deer and cattle, the lumen of the rete ovarii opens directly into the infundibulum near its attachment to the ovary. This serendipitous discovery followed the serial sectioning of over 100 ovaries. Secretions through this tuboretial opening may affect reproductive processes. Obstructions could explain the development of cysts of clinical importance in both human and veterinary medicine. This rather obscure structure may have more significance than previously recognized.
Filamentary tubular inclusions in type II pneumocytes of the guinea pig
Authors: Manabe Toshiaki , Ikeda Hiromi
Published: February 2005

The type II pneumocytes of guinea pigs were studied with a transmission electron microscope. It was shown that 5–20% of type II cells contained filamentary tubular inclusions. No reports of similar structures in type II cells of any species have been found in the literature to date.

These inclusions measured 90 nm in diameter, varying up to 3 μm in length, and were generally present in the basal and lateral portions of the cells with a close association to the lamellar bodies. They were usually straight but could be curved and tended to aggregate into parallel stacks. In cross‐sections, these filamentary tubular inclusions were surrounded by a thickened unit membrane and were composed of microfilaments arranged in circular fashion around a central core. In longitudinal sections, they consisted of rod‐like bodies with three lines of filaments.

The possible function of the filamentary tubular inclusions is also discussed.
Immunoelectron microscope observations on secretion of human placental lactogen (hPL) in the human chorionic villi
Authors: Fujimoto Sunao , Hamasaki Kunshige , Ueda Hiroshi , Kagawa Hirohiko
Published: February 2005

Immunoelectron microscope localization of human placental lactogen (hPL) was investigated in the chorionic villi from week 7 to full‐term gestation with the protein A–gold technique. With specific antiserum against hPL, immuno‐reactive gold particles were found to be preferentially located in Golgi‐derived, electron‐dense small granules of 80–180 nm in the syncytiotrophoblast. Our electron micrographs indicate that these small granules increase in number in the course of gestation and are released by exocytosis from the apical cell surface. The present study reveals that hPL is segregated from the Golgi apparatus, stored in the syncytiotrophoblast as secretory granules, and released into the maternal blood.
Significance of the increase in glucose 6‐phosphatase activity in skeletal muscle cells of the mouse by starvation
Authors: Hirose Kazuto , Watanabe Jun , Kanamura Shinsuke , Tokunaga Hirohiko , Ogawa Ryokei
Published: February 2005

The effects of starvation on glucose 6‐phosphatase (G6Pase; EC 3.1.3.9., D‐glucose 6‐phosphate phosphohydrolase) and glycogen phosphorylase (EC 2.4.1.1.) activities, and on glycogen content, were studied in skeletal muscles (m. rectus femoris) of mice. In the muscle cells from fed animals, the cytochemical reaction product for G6Pase activity was observed in moderate amounts in the terminal cisternae of sarcoplasmic reticulum and in small amounts in the nuclear envelope, and was rare or absent in the intermyofibrillar sarcoplasmic reticulum. After 4 days of starvation, however, the reaction product became abundant in all of the terminal cisternae, intermyofibrillar sarcoplasmic reticulum, and nuclear envelope. Biochemical G6Pase and glycogen phosphorylase a (active form) activities were higher in the muscles of starved mice than in those of fed animals. The glycogen content decreased markedly in the muscles of starved mice. The results suggest that the role of the increased G6Pase in skeletal muscle cells of starved mice is to release glucose into the blood by hydrolyzing glucose 6‐phosphate produced through the increased phosphorylase activity.
Disposition of the manchette and related events in the feline spermatid
Authors: Sickels Kathy I. , Heath Everett
Published: February 2005

The manchette is a transient microtubular organelle previously considered to “disappear” prior to formation of the definitive midpiece of the spermatozoon. Goodrowe and Heath (1984) have suggested, however, that in stallions the final disposition of the microtubules of the manchette is into the residual cytoplasm. In the present study, spermiogenesis was examined by transmission electron microscopy of testicular samples from eight cats. Feline spermatids also had a manchette of cylindrical shape, largely located in a cytoplasmic collar peripheral to the presumptive midpiece. The parallel microtubules of the manchette were interconnected by arms. Some of these arms were still present after rupture of the manchette cylinder and movement of the microtubules into the residual cytoplasm. On displacement of the manchette microtubules, mitochondria, spherical in shape and peripherally located, moved centrally to elongate and encircle the flagellum to form the definitive midpiece.
Morphometric analysis of the growth of the normal fetal guinea pig lung
Authors: Collins Margaret H. , Kleinerman Jerome , Moessinger Adrien C. , Collins Alexander H. , James L. Stanley , Blanc William A.
Published: February 2005

The structural development of the fetal guinea pig lung is described and quantified morphometrically in this report.

At 35 days gestation the lung is in the pseudoglandular phase of growth, by 40 days it is in the canalicular phase, and at 50 days the saccular growth phase has begun. At term (67 days), the fetal guinea pig lung appears mature.

From the beginning of the canalicular to the end of the saccular phases, the correlation coefficient between lung volume and gestational age is +.98, between internal surface area and gestational age is +.94 and between total number of saccules and gestational age is +.97. Internal surface area (ISA) correlates closely with lung volume (r = +.99) and the correlation coefficient between total number of saccules and lung volume is +.98. At term, lung volume is 4.22 ml. ISA is 0.5 M2, and total number of saccules is 253 million. Parenchymal growth is achieved by increases in both number and size of airspaces in the canalicular phase, primarily by increases in number during the early saccular phase and largely by increases in airspace size near term.

The total length of parenchymal elastic tissue increases from 223 M at 45 days gestation to 5,253 M at term. Elastic tissue fibers first appear in the parenchyma of the fetal guinea pig lung during the canalicular phase, when the rate of saccule formation is high. The quantitative increase in elastic tissue correlates closely with the increase in the total number of saccules from day 45 to day 60 of gestation (r = +.99). The rate of elastic tissue growth increases sharply in the late saccular phase, coinciding with the period of greatest saccular expansion. These data suggest an interdependent relationship between saccular growth, i.e., proliferation and expansion, and the development of lung parenchymal elastic tissue.
Adipocyte development in primary rat cell cultures: A scanning electron microscopy study
Authors: Richardson R. L. , Hausman G. J. , Campion D. R. , Thomas G. B.
Published: February 2005

This study utilized scanning electron microscopy (SEM) techniques to observe primary cultures of stromal‐vascular (SV) cells derived from postnatal rat inguinal adipose tissue. Cells were grown on collagen‐coated, fibronectin‐coated, or uncoated glass coverslips. Coverslips were normally fixed in glutaraldehyde, osmium tetroxide, dehydrated, and critical‐point‐dried. Other coverslips were frozen in isopentane (cooled in LN2) and dried or fixed in Baker's formalin for demonstration of inosine diphosphatase (IDPase) by X‐ray microprobe analysis (XRMA). Adipocyte morphologies were similar on all substrates. At 2 days of culture, actin cables were detected extending from developing adipocytes. No difference in actin cable structure, cellular shape, or lipid accumulation was observed among the different substrates. Some stromal cells did not accumulate lipid but proliferated into a multilayer by 9 days in culture. Inosine diphosphatase was detected in the Golgi apparatus of developing adipocytes utilizing the technique of XRMA. This study demonstrates the potential for using SEM and XRMA techniques to define morphological features and cytochemical markers of adipocytes in vitro and the response of primary cultured rat SV cells to other attachment substrates.
Prenatal development of the composite occipito‐atlanto‐axial synovial joint cavity in the dog
Authors: Watson Alastair G. , De Lahunta Alexander , Evans Howard E.
Published: February 2005

In the dog, the synovial cavities of the atlanto‐occipital and atlanto‐axial joints communicated to form a single large composite joint cavity. The prenatal development of this composite occipito‐atlanto‐axial joint cavity was studied by examining 26 serially sectioned dog embryos and fetuses that ranged in size from 19 to 68 mm crown‐rump length, and were between 30 and 42 days of gestational age. In the composite occipito‐atlanto‐axial joint, trilaminar interzones developed at 19–22 mm (30–31 days), joint cavities opened at 27–32 mm (33–34 days), and the atlanto‐occipital and atlanto‐axial cavities first communicated at 48 mm (37 days).
A rare human variation: The relationship of the axillary and inferior subscapular nerves to an acessory subscapularis muscle
Authors: Breisch Eric A.
Published: February 2005

A case of bilateral occurrence of a variant subscapularis muscle is reported. The superior lateral aspect of each subscapularis muscle presented a small accessory muscle with an accompanying tendon that inserted into the lesser tubercle of the humerus along with the primary tendon of the subscapularis muscle. Each accessory subscapularis muscle was separated from the primary subscapularis muscle by the axillary and inferior subscapular nerves. No branches of the axillary or inferior subscapular nerves supplied the primary subscapularis muscle or the accessory muscle while the nerves passed through the myotendinous tunnel. The relationship of the nerves with the variant subscapularis muscles has clinical significance with regard to entrapment neuropathy.
Nomenclatural review of long digital forelimb flexors in carnivores
Authors: Spoor C. F. , Badoux D. M.
Published: February 2005

A hitherto‐unknown atavistic muscle in the dog initiated a review of the literature on the homologies and nomenclature of the forelimb flexors in carnivores and man. A consequence is that we recommend a revision of the nomenclature in the Nomina Anatomica Veterinaria (Ithaca, New York, 1983) so that it is in agreement with the Nomina Anatomica (Wilkins, Baltimore, 1983). This revision mainly consists of the incorporation of the terms M. palmaris longus and Mm. flexores breves manus.
Spatial distribution of twitch and tonic fibres in a snake muscle one myofibre thick
Authors: Robinson Andrew J.
Published: February 2005

The spatial distribution of twitch and tonic fibres in a snake muscle one myofibre thick (ventral costocutaneous) has been investigated. It was found that small groups of like fibres were favoured at the expense of larger groups when compared with sequences generated by a computer in which fibres were distributed randomly. The number of times that like fibres occurred next to one another was used as another measure of their spatial distribution. The number of adjacencies of like fibres was less than the expected number of adjacencies determined both by random sequences and by probability theory. The expected number of adjacencies determined by means of random sequences and a priori probability theory were almost identical. This dispersion of like fibres may reflect processes that occur during muscle development and may have functional implications.
Endocytic appartus and transcytosis in epithelial cells of the vas deferens in the rat
Authors: Hermo L. , de Melo V.
Published: February 2005

The apex of the principal epithelial cells lining the vas deferens of the rat contains coated pits in continuity with the apical plasma membrane and large subsurface‐coated vesicles (100–125 um). In the apical cytoplasm, large, pale, uncoated vesicles (150–300 nm), small coated and uncoated vesicles (50–60 nm), uncoated vesicles about 75–90 nm, and membranous apical tubules are present, in addition to large, vacuolar, pale, multivesicular bodies, dense multivesicular bodies, and secondary lysosomes seen deeper in the cytoplasm amongst numerous ER cisternae, saccules of the Golgi apparatus, and mitochondria.

The endocytic activity of these cells was investigated by using cationic ferritin (CF) as a marker of adsorptive endocytosis and native ferritin (NF) for demonstrating fluid‐phase endocytosis. These tracers were injected separately into the lumen of the vas deferens, and the animals were killed at various time intervals thereafter from 2 to 90 minutes. At 2 minutes CF was seen bound predominantly to microvilli and to areas of the apical plasma membrane delimiting coated pits as well as in large, coated vesicles. At 5 and 15 minutes the tracers were seen in apical tubules and pale multivesicular bodies; at 30 minutes moderately dense multivesicular bodies were labeled. At 1 hour and longer time intervals dense multivesicular bodies and secondary lysosomes were labeled. NF followed the same pathway as CF; however, no binding to microvilli or areas delimiting coated pits was observed. The numerous other vesicular structures, i.e., the large uncoated vesicles (150–300 nm) and the small coated and uncoated vesicles (50–60 nm), never became labeled with the tracers and therefore were not involved in the endocytic process. There was, however, and exception in the case of several small (75–90 nm) uncoated vesicles seen deeper in the apical cytoplasm of these cells which were labeled exclusively with CF. With time such vesicles appeared along the lateral and basal surfaces of these cells and discharged their content of CF into the lateral intercellular space or the connective tissue space at the base of these cells. Thus the principal epithelial cells in addition to sequestering the endocytosed tracers within secondary lysosomes where they are presumably degraded also appear to be involved in the transcytosis of material from the lumen of the vas deferens to the underlying lamina propria.
Morphology of the osteonal cement line in human bone
Authors: Schaffler Mitchell B. , Burr David B. , Frederickson Richard G.
Published: February 2005

While current consensus suggests the absence of collagen in osteonal cement lines, the extent of cement line mineralization and the nature of the ground substance within the cement line are unclear. Samples of human radius were examined by using scanning electron microscopy, electron microprobe, and histochemical techniques. X‐ray intensities were used to compare the amount of calcium, phosphorus, and sulfur in cement lines with amounts in surrounding lamellar bone. The results indicate that cement lines contain significantly less calcium and phosphorus, but significantly more sulfur, than surrounding bone matrix. The Ca/P ratio of cement lines was significantly greater than that of lamellar bone, suggesting that the mineral in cement lines may not be in the form of mature hydroxyapatite. No selective staining of the cement lines could be demonstrated by using periodic acid‐Schiff, Sudan black B, or alcian blue critical electrolyte concentration techniques.
Morphogenetic clonal growth of kidney epithelial cell line MDCK
Authors: McAteer James A. , Evan Andrew P. , Gardner Kenneth D.
Published: February 2005

MDCK (Madin‐Darby canine kidney) cells were cultured either (1) dispersed within hydrated collagen gel (HCG) or (2) seeded atop a collagen substrate and then immediately overlaid with HCG. Individual cells exhibited clonal growth in three dimensions to form spherical cysts made up of a simple epithelium enclosing a fluid‐filled lumen. The cells of MDCK cysts were polarized with the basolateral surface in contact with the collagen gel and the apical surface bordering the lumen. The ultrastructure of MDCK cysts showed similarities to distal nephron. The cells bore apical microvilli and solitary cilia and had occluding junctions and a simple basolateral surface. MDCK cysts increased in size (> 800 μm diameter) with continued culture. MDCK cysts grown between layers of HCG were stripped free of the overlying collagen to give direct access to basolateral surface membrane. Unlike monolayer culture, morphogenetic clonal growth of cell line MDCK produces a polarized cell population with a true lumenal and basolateral surface. Collagen‐gel‐cultured MDCK cysts provide an easily manipulable in vitro cell system that may offer unique advantages for the study of renal cell structure and function.
Localization of calcium in vas deferens using 45Ca EM autoradiography: Relationship to species and the effect of 45Ca removal
Authors: McGuffee Linda J. , Little Sally A. , Skipper Betty J.
Published: February 2005

The distribution of calcium was determined in the vas deferens of the guinea pig using 45Ca electron microscopic autoradiography of rapidly frozen, freeze‐dried, and embedded tissue. A selective accumulation of calcium at the plasma membrane and SR was observed in vas deferens that had been incubated in 45Ca for 65–85 min prior to rapid freezing. Rinsing the tissue in nonradioactive calcium for 6 min prior to rapid freezing significantly altered the distribution of calcium among the plasma membrane, mitochondria, and cytoplasmic matrix. The influence of species on the observed distribution of calcium was also examined. The distribution of calcium in the guinea pig was deferens was not significantly different from that in the rabbit vas deferens when the tissues were prepared under identical conditions.
A classification of Sharpey's fibers within the alveolar bone of the mouse: A high‐voltage electron microscope study
Authors: Johnson Roger B.
Published: February 2005

In the remodeling interdental septum of the mouse, four types of Sharpey's fibers were observed. Classification of these fiber types was based on characteristics of their termination within the septum in relation to the resorption‐related reversal line separating old and new bone. “Severed fibers” were located only within old bone and terminated at the reversal line. “Arborized fibers” were located only within new bone and terminated therein. “Adhesive fibers” were located within new bone and terminated within a heavy band of granular material at the reversal line. “Continuous fibers” had components within old and new bone. These components were connected across the reversal line by nonstriated fibrils. Adhesive fibers were the least numerous type; severed and arborized fibers were observed at nearly equal frequency. Continuous fibers were the most numerous type, their numbers being significantly greater than any of the other types (P<.001). Mean numbers of continuous fibers were greater than the mean total of the three other fiber types (P<.001). Mean numbers of severed, adhesive, and arborized fibers were not statistically different. The study suggested that continuous fibers could be transalveolar—that is, ones which pass through the septum without interruption joining fibers of the adjacent periodontal ligament. Maintenance of their spatial continuity appeared to require a connecting protein to orient new unit collagen fibrils to old ones in areas of reversal. Thus, transalveolar fiber bundles could be characterized as being composed of old and new segments joined by a connecting protein. As their unit collagen fibrils did not cross resorption‐related reversal lines these fibers were spatially continuous but temporally discontinuous.
Specific binding sites for transferrin on ameloblasts of the enamel maturation zone in the rat incisor
Authors: McKee M. D. , Zerounian C. , Martineau‐Doizé B. , Warshawsky H.
Published: February 2005

During enamel maturation in rodents, an iron‐containing pigment is deposited into the surface layer of the enamel. Maturation zone ameloblasts presumably are responsible for this deposition. The presence of large amounts of ferritin in the cytoplasm of these cells suggests that they receive iron, presumably from circulating transferrin. An in vivo radioautographic binding assay using iodinated transferrin was used to determine if indeed maturation ameloblasts possess transferrin receptors at their cell surfaces. Experimental rats received systemic injections of labeled transferrin while control rats received injections of labeled transferrin plus a large excess of unlabeled transferrin in order to complete with the labeled transferrin for available specific receptors. Light microscope radioautography showed that ruffle‐ended ameloblasts (RAs) of the enamel maturation zone had a high density of specific receptors for transferrin relative to smooth‐ended ameloblasts (SAs). Electron microscopy and energy‐dispersive X‐ray spectroscopy confirmed the presence of ferritin and iron, respectively, within these cells. It is postulated that the iron responsible for enamel pigmentation is transported by transferrin to maturation ameloblasts and is bound to specific transferrin receptors found mostly on RAs and that the modulation of these cells into SAs results in a loss of most of these receptors.
Differential uptake of 3H‐thymidine by structures of the pia‐arachnoid and cerebral cortex distal to the interrupted middle cerebral artery
Authors: Myers Steven F. , Coyle Peter
Published: February 2005

Tritiated thymidine accumulated in pial surface structures 1–10 days after interruption of the right middle cerebral artery (MCA) in the rat. Essentially no radioactive marker was present in the underlying cortical territory of the interrupted MCA other than at the operation site. Control meninges, cortex contralateral to the operated MCA, and structures proximal to the operation site were without appreciable accumulation of 3H‐thymidine. Thus, the marked cellular proliferative response to MCA interruption was localized to structures of the pia‐arachnoid overlying the cortical territory of the interrupted MCA. The data suggest that after MCA occlusion a cellular proliferative response contributes to the expansion of preexisting pial surface collateral vessels and that the expansion does not extend into the parenchyma.
Cell cycle and neuroepithelial cell shape during bending of the chick neural plate
Authors: Smith Jodi L. , Schoenwolf Gary C.
Published: February 2005

Neuroepithelial cells change shape from spindle‐like to wedge‐like within three restricted areas (hinge points) of the bending neural plate. The mechanisms underlying these localized cell shape changes and the specific role that these changes play in bending are nuclear. This study was designed to determine whether changes in neuroepithelial cell shape involve basal cellular expansion owing to alteration of the cell cycle. Neurulating chick embryos were treated with colchicine to arrest and accumulate cells in metaphase, and colchicine indices and cell generation times were calculated for the neural plate. During bending of the neural plate, cell generation time in the median hinge point, which contains predominantly wedge‐shaped cells, was significantly longer than that in adjacent lateral areas of the neural plate, which contain predominantly spindle‐shaped cells. In addition, cell generation time in the flat neural plate, which contains predominantly spindle‐shaped cells and has not yet differentiated into the median hinge point and lateral subdivisions, was identical to that in lateral areas of the bending neural plate but was significantly shorter than that in the median hinge point. These results support the hypothesis that changes in neuroepithelial cell shape from spindle‐like to wedge‐like involve basal cellular expansion owing to alteration of the cell cycle. Additional tests of this hypothesis and studies on the role of localized cell shape changes in neurulation are in progress.
Morphologic characterization of cultured smooth muscle cells isolated from the tracheas of adult dogs
Authors: Tom‐Moy May , Madison J. Mark , Jones Cary A. , de Lanerolle Primal , Brown James K.
Published: February 2005

The goals of our study were to isolate smooth muscle cells from the trachealis muscle of adult dogs and to characterize the cells morphologically when they were maintained in primary culture. Enzymatic digestion of the muscle yielded 4.8 ± 1.8 × 106 viable smooth muscle cells per gram of tissue. When placed in culture, these cells rapidly proliferated until confluence was reached. The proliferating cells in culture differed from the cells in the intact tissue in that they stained less intensely for smooth muscle myosin, developed immunoflurescent staining for the intermediate filament protein vimentin, and lost many of the ultrastructural properties of the intact muscle. Only within nodules of cells in the confluent cultures were these ultrastructural properties preserved. Cultures of canine tracheal fibroblasts differed from these smooth muscle cell culturs in that the fibroblasts did not stain for smooth muscle myosin and did not form nodules at confluence. We concluded that adult canine airway smooth muscle cells may be maintained in primary culture, that the confluent cultures contain nodules of cells with many morphologic characteristics of the intact muscle, and that these preparations may be distinguished from cultured canine tracheal fibroblasts on specific morphologic grounds.
Heterotopic synaptic bodies in the auditory hair cells of adult lizards
Authors: Miller Malcolm R. , Beck Janet
Published: February 2005

The auditory hair cells of adults of eight species of lizards (three gekkonids: Coleonyx variegatus, Gekko gecko, and Cosymbotus platyurus; two teiids: Ameiva ameiva and Cnemidophorus tigris; one anguid: Celestus costatus; one lacertid: Podarcis (Lacerta) sicula; and one iguanid: Crotaphytus wislizeni) were studied by transmission electron microscopy. Heterotopic synaptic bodies were found in some of the auditory hair cells of all of the above species, occurring frequently in the gekkonids but infrequently in other species.

The groups of heterotopic synaptic bodies occurred mainly in the infranuclear cytoplasm between the hair cell nucleus and the hair cell plasma membrane. The groups of synaptic bodies that were close to the hair cell nucleus were usually associated with specialized arrays of rough and smooth endoplasmic reticulum. The numbers of heterotopic synaptic bodies were greatest in the gekkonid species and were especially large in Coleonyx variegatus, where an average of 36.8 synaptic bodies occur in one group. The functional significance of the presence of heterotopic synaptic bodies in the auditory hair cells of adults animals is not known.
The “in situ” immune response in lymph nodes: A review
Authors: van Rooijen N.
Published: February 2005

For many years data on the development of specific antibody‐forming cells in lymph nodes were incomplete, fragmentary, and even contradictory. A number of recent studies have been performed, concerning (1) their overall architecture; (2) migration of B‐lymphocytes; (3) localization of accessory cells and T‐lymphocytes which are believed to be involved in humoral immune responses; and (4) localization patterns of specific antibody‐forming cells developing during thymus dependent and thymus independent immune responses. Comparison of these new results with those of earlier studies suggests a single route of migration followed by all cells which will differentiate into antibody‐forming cells. During their differentiation into antibody‐forming plasma cells, antigen reactive B‐cells migrate along the required accessory cells and/or T‐lymphocytes.
Regeneration of submandibular gland autografts in sympathectomized rats
Authors: O'Dell Norris L. , Sharawy Mohamed , Richardson Mary C. , Pennington Catherine B.
Published: February 2005

This morphologic study compares the regenerative response in submandibular gland (SMG) autografts placed in the tongues of previously sympathectomized rats to autografts placed in tongues of sham‐sympathectomized rats. We hypothesized that sympathectomy would alter the process of cellular proliferation and inhibit cytodifferentiation in regenerating SMG autografts. Either 1 week, or 8 to 11 weeks following the SMG autografting procedure, the rats were sacrificed and their tongues were removed and sectioned in a cryostat. Frozen tissue sections containing the SMG autografts were either reacted for cholinesterase activity, treated with a glyoxylic acid mixture to induce histofluorescence, or stained for histologic examination. In addition, 3H‐thymidine labeled and unlabeled cells were counted in autoradiographs of 1‐week autografts, and these counts were used to calculate labeling indices. The 1‐week SMG autografts from both the sympathectomized and the sham‐sympathectomized rats were similar in histologic appearance, and neither group of autografts contained cholinesterase‐positive or monoaminergic nerve fibers. The 8‐ to 11‐week autografts from sympathectomized and sham‐sympathectomized rats contained cholinesterase‐positive fibers, but monoaminergic fibers were present in the autografts only from the sham‐operated rats. Acinar cells were observed in one‐third of the 8‐ to 11‐week autografts of both the sympathectomized and the shamsympathectomized rats. This finding suggests that sympathectomy did not preclude cytodifferentiation in the autografts. The autoradiographic data revealed no statistically significant difference between the mean labeling indices of the 1‐week autografts from the sympathectomized and sham‐sympathectomized rats, which suggests that sympathectomy also did not alter the level of cellular proliferation in the autografts.
Effect of thyrotropin‐releasing hormone on development of the pituitary–thyroid system in fetal rats in organ culture
Authors: Takizawa Tatsuya , Yamamoto Masako , Arishima Kazuyoshi , Eguchi Yasunobu
Published: February 2005

Six groups of thyroid glands from 18‐day fetal rats were explanted to organ culture for 2 days. In one group, thyroid was cultured alone and in the remaining five groups thyroid was cocultured with pituitaries from fetuses ranging in age from 17 to 21 days. In each of the groups, half of the cultures had thyrotropin‐releasing hormone (TRH) added to the medium. Histometric parameters of the thyroid follicle such as diameter and cell height were used as indicators of development of the thyroid gland. When 18‐day thyroid was cultured alone, addition of TRH did not accelerate development. When either one 18‐day or two 17‐day pituitaries were cocultured with thyroid, a significant increase in diameter and cell height was seen. Addition of TRH to the medium induced little or no further change. When the thyroid was cultured with 19‐ to 21‐day pituitaries, a marked increase in thyroid development was observed; and the addition of TRH caused further acceleration in thyroid development. These results suggest that, in organ culture, 17‐ to 18‐day pituitary glands can release some thyrotropin (TSH) with or without additional TRH. Older pituitaries (19‐ to 21‐day) apparently can release an amount of TSH in the presence of TRH that is greater than their own spontaneous TSH secretion.
Vasoactive intestinal peptide‐immunoreactive nerves in the rat kidney
Authors: Knight David S. , Beal John A. , Yuan Zhi Ping , Fournet Timothy S.
Published: February 2005

An indirect immunohistochemical method in which an avidin‐biotinylated horseradish peroxidase complex is bound to the secondary antibody was used to visualize vasoactive intestinal peptide‐immunoreactive (VIPI) nerves in the rat kidney. Rats were perfused with 4% paraformaldehyde or 2% paraformaldehyde + 0.15% picric acid in 0.1 M phosphate buffer, then transferred to the buffer. After 24–48 hours, the kidneys were sectioned with a Vibratome at 200 or 300 μm and incubated in the primary antiserum for 18 hours at room temperature. A sparse plexus of VIPI nerves innervates the rat renal calyx. Some VIPI nerves innervate interlobar arteries and each succeeding segment of the arterial tree including afferent arterioles, but most innervate arcuate and interlobular arteries. VIPI axons do not innervate each arcuate artery or each interlobular branch of an arcuate artery with equal density. Although some axons follow each interlobular branch, most form a dense plexus on only one or two branches. Therefore, most VIPI nerves in the rat kidney innervate a restricted segment of the renal arterial tree. These nerves may be efferent and may selectively dilate arcuate and smaller arteries, or they may be afferent and may sense local changes in mechanical or chemical parameters.