bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental production of perfect cyclopia by removal of the telencephalon and reversal of bilateralization in somite‐stage chicks
Authors: Rogers K. T. 
Published: February 2005

AbstractThe telencephalon was removed with iridectomy scissors in stages from 1 to 20 somites, with the vast majority of operated chicks being at 5 to 10 somites. The most chance of successfully producing cyclopia appears to be at 6 to 7 somites. Twelve cyclopean embryos, with operated stages ranging from 5 to 10 somites, were produced among the first 271 operations. Subsequently, 398 operations, concentrated on 9‐ to 10‐somite embryos, proved that cyclopia is very much less apt to follow this sort of operation at these stages than at the very slightly younger stages.Serial sections of the cyclopean embryos were stained with a modification of the Bodian protargol stain. An oral hypophysis is usually present in these embryos, making them in this respect similar to the majority of cyclopean embryos for which this point is reported in the literature, but making them different from experimentally produced cyclopean amphibian embryos reported in the literature. The sequence of fusion of extrinsic ocular muscle components and the patterns of their nerves, as the cyclopean defect becomes more severe, indicates that the reversal of bilateralization is a ventralization.Coupled with biochemical work on the chick and the more recent of the biochemical work of others on amphibia, the results allow one to suggest that experimental stimuli resulting in the cyclopean mode of development may act either on prechordal substrate or on neural tissue of telencephalon and diencephalon, or on both substrate and neural tissue, and that they may be effective over a considerable period of time, up to and including the period of actual bilateralization of the optic primordia.
A quantitative study of the effect of heat on germinal epithelium of rat testes
Authors: Chowdhury A. K. , Steinberger E. 
Published: February 2005

AbstractA quantitative study of changes in the germinal epithelium of rat testes exposed to 43°C for 15 minutes was performed. Testicular tissue was studied at intervals of 2, 4, 6, 8 and 26 days after exposure to heat. The frequency distribution of the various stages of spermatogenesis, the resting spermatocytes, spermatogonia and Sertoli cells were not affected by the exposure to heat. On the other hand, primary spermatocytes in stage IX (leptotene), to and including dividing spermatocytes in stage XIV, were injured, excepting for pachytene spermatocytes in stages V and VI of spermatogenesis. The spermatids were affected by heat only in step 1 and the early part of step 2 of spermiogenesis. Those beyond step 2 continued to mature and form adult spermatozoa. The data indicate that heat produces selective damage to the germinal epithelium affecting only specific types of germinal epithelium cells.
The presence of water on the respiratory surfaces of the lung
Authors: Terry Robert James 
Published: February 2005

AbstractInterest in the possibility of a fluid medium for the transport of oxygen in the respiration of terrestrial vertebrates was aroused by the author's discovery of a watery fluid in the bronchioles of human cadavers and of domestic animals. In the literature of respiration the tolerance of water injected into the lungs of living animals had been demonstrated by Claude Bernard in 1869. Water as the vehicle for oxygen in the respiration of terrestrial invertebrates has been recorded many times. The life of fishes and of invertebrates inhabiting the waters of the world is dependent upon oxygen dissolved in this medium. The present paper records: (a) The author's experience in seeking and recording evidence of the presence of a watery medium in the respiratory organs of a series of vertebrates, and (b) presents evidence in explanation of the method of oxygen transport from the termination of the bronchial system into the capillary blood‐stream of the lung. The investigation called for special techniques, apparatus and instruments; these are described. The period of investigation extended, with many interruptions, from '10 to '60; during which period reports of progress have been published.
Fine structure of the rat renal papilla
Authors: Bulger Ruth Ellen , Trump Benjamin F. 
Published: February 2005

AbstractThe fine structure of the rat renal papilla was studied after fixation with various fixative solutions and by using three modes of fixative application: immersion, vascular perfusion and injection of fixative into the renal pelvis. The morphology of the following was described: thin limbs of Henle's loop, collecting ducts, capillaries, interstitial cells, and interstitium. Several previously undescribed features were seen. Two types of capillaries were identified on the basis of their fine structure. Regions identified as limbs of Henle had at least two types of mural structure differing in degree of cellular interdigitation. In addition, numerous projections were seen extending from the basal cytoplasm of capillary endothelium and collecting duct epithelium through the basement membrane into the interstitium.
The visual cells of the chicken as revealed by phase contrast microscopy
Authors: Meyer David B. , Cooper Terrance G. 
Published: February 2005

AbstractPhase microscopic investigations of Kolmer‐fixed, depigmented sections of the adult chicken retina have provided photomicrographic evidence of the existence of three different photoreceptors: single rods, single cones, and double cones. The rod extends the entire thickness of the visual cell layer and is characterized by a uniformly thick outer segment and a hyperboloid‐containing inner segment which is devoid of an oil droplet. The single cone is the shortest element; it contains a red oil droplet. The double cone consists of two unequal members, a tall, slender chief cone and a broad accessory cone. The chief component contains a large yellow oil droplet, whereas the accessory cone houses a small, oval, yellowish‐green droplet and a characteristically large, oval paraboloid. The rod hyperboloid and the accessory cone paraboloid contain glycogen. No colorless droplets have been observed. Owing to the close association between oil droplet color and cone type, three colored layers of oil droplets are formed within the thickness of the retina: a proximal row of red droplets (the short, single cones), an intermediate layer of yellowish‐green droplets (the accessory cones), and a distal row of yellow droplets (the tall chief cones).
Deviations in the sequence of appearance of primary centers of ossification in the feet of human fetuses with cleft lip and/or palate
Authors: Kraus Bertram S. , Ahern Suzanne 
Published: February 2005

AbstractThe feet of 35 human fetuses with cleft lip and/or palate and 208 human fetuses without cleft Lip or palate were cleared and stained, and their conformity to the “normal” sequence of appearance of the primary centers of ossification in the 19 post‐tarsal bones was noted. An arbitrary definition of a significant deviation from the normal sequence was established and a system of evaluating the relative severity of deviations was set up. The relative number of cleft fetuses showing deviations from the accepted sequence (42.9% ) was significantly higher than of non‐cleft fetuses (10.6%). The cleft and non‐cleft deviant fetuses were not significantly different in relative severity. There was no difference between the two series in the relative frequency with which specific bones were affected. In each series the fifth distal phalanx was most frequently affected. In both series, deviations in the order of initial ossification more frequently involved the seventh to tenth phalanges in the sequence. Asymmetry was of common occurrence in deviants of both the cleft and non‐cleft series. There was no significant difference in the number of deviant centers per fetus in the cleft and non‐cleft series.The biological mechanisms underlying the orderly and regular sequence of appearance of ossification centers in the foot are not known, hence, the nature of the interference with the “normal” sequence cannot be described.
Growth of the face and jaws after resection of the septal cartilage in the rabbit
Authors: Sarnat Bernard G. , Wexler Manuel R. 
Published: February 2005

AbstractVarying amounts of the cartilaginous nasal septum were resected in 15 growing rabbits at 21 days of age. Ten additional rabbits were used as unoperated on and operated on controls. The postoperative survival ranged from 105 to 145 days.Within 60 to 90 days postoperatively, antemortem findings were noted in the experimental animals of a shorter snout and overeruption and malocclusion of the incisors. Postmortem gross findings of the dissected, sectioned and x‐rayed skulls of the experimental animals revealed that the snout was shorter and smaller with a severe relative mandibular prognathism, the nasal and premaxillary bones were smaller, the nasal cavity and piriform aperture were smaller than in the control animals. As a result of the shorter snout the upper incisors were lingual to the lower incisors. This was the reverse of the normal findings. In addition, the incisors were overerupted, malaligned and fractured. At the posterior border of the septal defect a marked downward and forward deflection of the nasal bones was noted. This was in contrast to the smoothly curved dorsum of the operated on and unoperated on control animals. The extent and severity of the deformity varied approximately with the extent of the septal defect.
The fine structure of rat liver sinusoids, space of Dissé and associated tissue space
Authors: Burkel William E. , Low Frank N. 
Published: February 2005

AbstractThree structurally distinct zones are present in the liver sinusoid. The endothelium and basement (boundary) membrane of the portal vein extend uninterruptedly into the peripheral zone. The intermediate zone, comprising 90% or more of the length of the sinusoid, possesses a fenestrated lining and no basement membrane. The short central zone has unfenestrated endothelium and a basement membrane. Both are continuous with those of the central vein. The space of Dissé encircles all three zones of the sinusoid. It contains fat storage cells, perisinusoidal cells, numerous microvillae of liver cells and reticular fibers. These fibers are bundles of unit collagen fibers enclosed by cytoplasm of nearby cells. The space of Dissé is continuous with the tissue space at both ends of the sinusoid. The liver cells lack a basement membrane whether they abut on the space of Dissé or on the tissue space proper.The unique feature of liver fine structure is the combination of fenestrations and lack of basement membranes in the intermediate zone of the sinusoid. Blood plasma is thereby afforded intimate contact with the parenchymal cells and has access to the tissue space at both ends of the sinusoid. This structural situation fits the known facts of liver function.
Fine structure of the lymphatic capillary and the adjoining connective tissue area
Authors: Leak L. V. , Burke J. F. 
Published: February 2005

AbstractThe lymphatic capillaries possess salient morphological features which differentiate them from the blood capillaries. Instead of a definitive basement lamina surrounding the lymphatic wall, there are numerous fine filaments (about 60 A in diameter) that are attached to the lymphatic endothelia at areas of increased electron density that are similar to half desmosomes. The filaments extend for varying vessel to the surrounding connective tissue. Endothelial projections occur along both the luminal and abluminal surfaces of the cell. The intercellular junctions are varied in structure along the lymphatic wall. Terminal processes of adjacent endothelial apposed without overlapping. At various points along the intercellular junction the apposed surface membranes are held in close apposition by adhesion devices, (a) zonula occludens, (b) zonula adhaerens, and (c) macula adhaerens (desmosome). Frequently open junctions are observed along the lymphatic wall. It is suggested that the areas between apposing membrane surfaces which lack attachment devices may represent specialized regions along the lymphatic wall that are easily separated and would permit the passage of excess tissue fluids and large molecules into the lumen of the lymphatic vessel. The transport of colloidal carbon particles across the endothelium in vesicles of various sizes and via intercellular junctions is demonstrated.
Perfusion‐fixation of the brain with chrome‐osmium solutions for the rapid Golgi method
Authors: Morest D. Kent , Morest R. R. 
Published: February 2005

AbstractThe characteristics of rapid Golgi impregnations of neurons in the brains of opossums, rats, rabbits, chinchillas, and cats, obtained with a method employing intracardiac perfusion with osmium tetroxide‐dichromate fixatives, are reported. Observations on all subdivisions of the brain were compared with immersion‐fixed Golgi preparations and formalin‐perfused brains prepared by Nissl or reduced silver methods. Perfusion‐fixation yielded more uniform and extensive Golgi impregnations, which were more representative of the varieties of neural structures than in immersion‐fixed preparations. The morphological details of fine neuronal processes, delicate dendritic branchlets and spines, and fine elements of the axonal plexuses were more clearly and consistently demonstrable. Observations with the polarizing microscope suggested that the Golgi impregnations contained silver dichromate and/or silver monochromate. The procedures and the predictability, nature, and histological reliability of the rapid Golgi method are discussed.
The histochemistry of mucins in certain primate salivary glands
Authors: Leppi T. John , Spicer S. S. 
Published: February 2005

AbstractSubmandibular and sublingual salivary glands of squirrel and rhesus monkeys and man contain histochemically demonstrable neutral mucosubstances, sialomucins and sulfomucins. Judged by results obtained with a variety of staining procedures and by the effects of prior sialidase digestion, periodate oxidation and certain chemical modifications on the several staining procedures, differences are revealed in the types of mucosubstances within each cell type. Specifically, sialic acid‐containing mucosaccharides are present uniformly in the mucous cells of the submandibular glands of both monkeys and in a posterior segment of the sublingual gland of the rhesus monkey. Sulfomucin is the predominant secretion of the sublingual gland of the squirrel monkey and is also found in the anterior portion of the sublingual of the rhesus monkey as verified by S35O4 = autoradiography. This latter sulfomucin is admixed with a small amount of sialomucin. One or the other or mixtures of these two mucins in about equal proportions are present in the mucous acini of human submandibular glands. Seromucous acini in the human submandibular gland form a granular secretion with strong affinity for aldehyde fuchsin possibly attributable to a sulfated mucosubstance. Other and perhaps some of the same seromucous acini in this gland produce a granular secretion containing sialic acid in probable proximity, as shown by the periodate‐para diamine procedure after sialidase, to a hexose or deoxyhexose. A sulfomucin forms the major secretory component in the mucous acini of human sublingual glands. However, some mucous acini in this sublingual gland produce a mixture of sialo‐ and sulfomucins either in different or the same cells. Seromucous demilunes or acini in the human sublingual gland produce a granular secretion rich in sialic acid like that in the submandibular gland.
An electron microscopic study on the innervation of the intracranial artery of the rat
Authors: Sato So 
Published: February 2005

AbstractTopographical variations in the innervation between different portions of rat intracranial artery have been studied by the aid of electron microscopy. Myelinated fibers are found only around the internal carotid and the proximal portion of the basilar arteries. Unmyelinated fibers are observed within the adventitia of the major intracranial arteries. These fibers diminish gradually in number as getting towards the periphery and completely vanish before the disappearance of the muscular coat of the artery. Most of small branch arteries have no vascular nerve around them, although they show one‐ or two‐layered arrangement of smooth muscle cells in the media. Some central branches of the internal carotid and the middle cerebral arteries are accompanied by unmyelinated fibers even after they penetrate into the brain tissue. The fine structures of the terminal portion of vascular nerve fibers, particularly the neuromuscular relationships, have also been described.
Suprarenal gland lymphatic drainage
Authors: Merklin Robert J. 
Published: February 2005

AbstractThe gross and microscopic anatomy of the suprarenal gland lymphatic system was studied in post mortem specimens and specimens in which the venous system was injected with blue latex solution.Extensive subserous lymphatic networks overlie the suprarenal gland. Deep to these networks are the lymphatic vessels proper of the suprarenal gland. These vessels lie within the suprarenal gland capsule and communicate with the subserous lymphatic network. Their primary routes of drainage, however, are directed medialward, passing to the thoracic duct cr cisterna chyli either directly or by way of regional lymph nodes. A few capsular lymphatic vessels extend toward the diaphragm or the kidney. The regional lymph nodes are small, few in number and situated at the lower medial aspect of the gland.Microscopic examination of serially sectioned suprarenal glands revealed a complete absence of lymphatic vessels in the cortical and medullary parenchymal tissue. Lymphatic vessels were found only in the capsule and in the adventitia of the central vein and its major tributaries.A close association between capsular lymphatic vessels and veins was noted and in a number of specimens capsular lymphatic vessels were traced to the inferior vena cava where they assumed a close relationship with vasa vasorum.
The synthesis and storage of protein by isolated lymphoid cells, examined by autoradiography with the electron microscope
Authors: Clark Sam L. 
Published: February 2005

AbstractAutoradiography with the electron microscope was employed to locate sites of synthesis and storage of newly‐formed protein in cells isolated from lymph nodes of immunized rabbits and incubated with tritium‐labelled leucine. The chief object of the investigation was to locate the site of sequestration of newly‐formed antibody during the half‐hour that intervenes between its synthesis and release from the plasma cell. By making counts of grains over nuclei, Golgi complex and ergastoplasm, and relating these to the relative volume of each region, evidence was obtained that, during the latent period of secretion, antibody moves into the Golgi region from its site of synthesis in the ergastoplasm. In analyzing the data, some of the difficulties involved in quantitative autoradiography were considered and the statistical inappropriateness of using mean grain counts and their standard errors to estimate the concentration of isotope was discussed. As an alternative with a sounder theoretical basis, the ratio estimate was adopted, and Fieller's theorem was used to obtain conservative estimates of confidence limits. The results of statistical analysis supported the biological conclusion that newly‐formed antibody migrates to the Golgi region, but the role of the Golgi complex in secretion of antibody remains to be explained.The hypothesis that plasma cells originate by differentiation from large lymphocytes received circumstantial support from the observation that among those cells active in synthesis of protein, a series transitional in structure from large lymphocytes to mature plasma cells could be assembled.
Dual innervation of the mammalian urinary bladder A histochemical study of the distribution of cholinergic and adrenergic nerves
Authors: El‐Badawi Ahmad , Schenk Eric A. 
Published: February 2005

AbstractThe pattern of autonomic innervation of the urinary bladder was studied in the cat, dog, rabbit and rat, using specific histochemical technics for acetylcholinesterase and norepinephrine. Cholinergic and adrenergic ganglion cells exist in all layers throughout the bladder wall. Large cholinergic and adrenergic nerve trunks coursing in the adventitial coat and deep lamina propria branch into the muscularis. The terminal cholinergic ramifications form a neuroterminal plexus which surrounds every smooth muscle cell in the bladder wall. The terminal adrenergic fibers are less abundant, do not form a plexus, and show regional variations in number at different levels and depths of the muscularis. These variations suggest that two regions of the bladder, namely the base and body, may be distinguished on the basis of differences in muscular innervation.In the lamina propria cholinergic and adrenergic nerves are grouped as deep and superficial subepithelial nerves. The latter form networks of variable complexity and supply fibers to the epithelium. Throughout the bladder wall, the blood vessels have a dual cholinergic and adrenergic perivascular plexus from which fibers extend into the media.Although the basic pattern of innervation is similar in the species studied, certain variations exist in the relative abundance and arrangement of epithelial and subepithelial nerves. The muscularis has a uniform cholinergic and a variable adrenergic innervation in different species.
A dynamic and static study of hepatic arterioles and hepatic sphincters
Authors: McCuskey Robert S. 
Published: February 2005

AbstractThe purpose of this investigation was to demonstrate the cytology of the sphincters of hepatic sinusoids, to elucidate further the pathway by which arterial blood is distributed to the sinusoids, and to study the hormonal and local regulation of arterial and portal venous blood flow through the sinusoids.The sphincters were found to consist of reticulo‐endothelial cells and were the primary site for the regulation of blood flow through the sinusoids. By contracting independently or in unison the flow of blood was regulated through individual sinusoids, through sinusoids supplying a portion of a lobule, or through sinusoids supplying a whole lobule. When the sphincter cells contracted, their nuclear region bulged into the lumen, thereby occluding it.Hepatic arterioles were found to wind around adjacent portal venules with an average curvature of 42° and communicated with sinusoids via arterio‐sinus twigs. No structural arterio‐portal anastomoses were observed; however, functional “arterioportal anastomoses” were formed by short twigs which terminated in sinusoids near their origins. No branches were found to terminate near central venules.The data suggest that the local regulation of blood flow through the hepatic sinusoids is mediated by vasodilator metabolites (adenosine and/or potassium) released from hypoxic hepatic cells as a result of the rapid glycogenolysis that accompanies hepatic cellular hypoxia.