bluuebunny/crossref_metadata_2025_split huggingface dataset:
The primary human oocyte: Some observations on the fine structure of Balbiani's vitelline body and the origin of the annulate lamellae
Authors: Hertig Arthur T. 
Published: February 2005

AbstractThe ultrastructural details of human oocytes from four primordial follicles and one early primary follicle are presented. A fifth primordial follicle is represented by a paraffin section stained by hematoxylin and eosin. The paranuclear Balbiani vitelline body, contsisting of a centrosome surrounded by endoplasmic reticulum, Golgi complexes, compound aggregates, annulate lamellae, and mitochondria is described. The annulate lamellae arise as an evagination from the outer leaflet of the nuclear envelope and interdigitate with folds of the endoplasmic reticulum which also is continuous with the outer leaflet of the nuclear envelope. Structural aspects of annulate lamellae are discussed in relationship to current ideas of nuclear membrane ultrastructure and to their possible role in nucleo‐cytoplasmic transfer. A biographical note on the life of Edouard Gérard Balbiani is presented.
Re‐examination of spermatogonial renewal in the rat by means of seminiferous tubules mounted “in toto”
Authors: Clermont Y. , Bustos‐Obregon E. 
Published: February 2005

AbstractObservations on dissected tubules, fixed in Carnoy, stained with hematoxylin and mounted “in toto” revealed that there were five distinct classes of type A spermatogonia. The type A1 found in stages II–VIII of the cycle of the seminiferous epithelium had round, pale‐stained nuclei, typically arranged in linear clusters of four or eight along the tubular wall. They all divided at stage IX to produce type A2 cells. These in turn divided at stage XII to produce type A3 spermatogonia. The type A2 and A3 cells had large ovoid nuclei containing globular masses of deeply stained chromatin and were randomly distributed in the space between Sertoli nuclei. The type A3 spermatogonia divided at stage XIV to produce type A4 cells. These had smaller nuclei, sometimes lobulated, containing more deeply stained chromatin granulation, free in the nucleus or adhering to the nuclear membrane. They divided in stage I of the cycle to yield two classes of spermatogonia: intermediate type and new type A1. Hence, type A1–type A4 spermatogonia were considered as “renewing stem cells.” The fifth class of type A spermatogonia (A0) was found at all stages of the cycle. Rare, isolated or in pairs, they had oval nuclei with deeply stained chromatin granulations. Seldom seen to divide, they did not appear to be actively involved in cell renewal and were tentatively considered as “reserve stem cells”.
On movement of muscles by galen of pergamon
Authors: Goss Charles Mayo 
Published: February 2005

AbstractGalen begins with definitions, giving the special differentiating characteristics of nerves, muscles, tendons, aponeuroses, fascia, and other connective tissue elements. He demonstrates that contraction is the specific activity of muscles. It occurs voluntarily through impulses from the brain carried by the nerves. Protagonists and antagonists are described and demonstrated by experiments with severing individuals and groups as well as with a model made of articulated bones and thongs attached in proper places to represent muscles. Attention is called to passive motion of muscles. The action of gravity is related to muscular action. Sustained contraction of muscles is called tonic activity. The effect of habit on muscles and the subconscious control of voluntary muscles are explained. Visceral organs and blood vessels are under the control of nature rather than the brain, and are thus contrasted with the muscles.
Development of the gonads in the female japanese quail
Authors: Kannankeril J. V. , Domm L. V. 
Published: February 2005

AbstractThe germ cells in the Japanese quail, appear in the gonadal area between two to two and one half days incubation with a preferential distribution favoring the left gonad. Proliferation of the primary or medullary cords from the germinal epithelium was observed between four and five and one half days. The secondary or cortical cords were found to proliferate in the left gonad on the sixth day. The right gonad revealed neither cortical cords nor cortex in any of the cases studied. It began to involute around eighth day and reached its minimum size by seven to ten days after hatching. In the adult it was composed of loose, or occasionally cord‐like, epithelial cells, sparsely scattered “fat laden” cells, masses of lymphocytes and fibrous connective tissue, the latter predominating in older stages. Germ cells either disappeared or could no longer be recognized in the right gonad by four days after hatching. In the left ovary oogonia began to show meiotic changes by the eleventh day and primary follicles were present on the day of hatching. Ovulation was observed as early as 45 days after hatching. In female embryos the right Mullerian duct underwent atrophy and became a rudimentary cloacal remnant between eight and 14 days. In males complete atrophy of both left and right Mullerian ducts occurred between seven and 13 days. The mesonephric ducts persisted in females and were demonstrable throughout post‐hatch period as thread‐like structures.
Observations on epidermal differentiation in the fetal rat
Authors: Bonneville Mary A. 
Published: February 2005

AbstractStudy of fetal rat epidermis has revealed the presence of a single layer of nonkeratinizing cells, the periderm, that covers the free surface of the skin during embryonic life. The periderm resembles structurally the epithelium lining the amniotic cavity, and the two are believed to be similar in function and embryonic origin.Observations of keratinization have shown that keratohyalin granules formed initially during fetal life may differ in structure from those formed during later fetal life and in the adult. Those formed first contain lipidlike globules embedded in a dense granular matrix. Those formed next contain dense patches of finely granular material embedded in a less dense matrix. Granules formed late in fetal life have a homogeneous structure and resemble those of adult skin.As in adult epidermis, tonofibrils, abundant in epidermal cells prior to cornification, probably contribute to formation of the keratohyalin granules. Also, as in adult tissue, ribosomes lie close to the surfaces of developing keratohyalin granules and seem to be involved in their formation.
An ultrastructural and histochemical study of rat atrial myocardium
Authors: Hibbs Richard G. , Ferrans Victor J. 
Published: February 2005

AbstractA study was made of the ultrastructural and histochemical characteristics of atrial muscle cells. The myofibrils of these cells do not converge at the nuclear poles as in the ventricular cells, but leave large sarcoplasmic spaces in the central cores, which contain mitochondria, small amounts of rough‐surfaced sarcoplasmic reticulum, free ribosomes and one or more well developed Golgi complexes. Numerous cytoplasmic granules, many of which are closely associated with the Golgi material, are present in these cells. These granules can be demonstrated in paraffin sections by the Bowie stain. The smooth‐surfaced sarcoplasmic reticulum of atrial fibers consists of a meshwork of interconnected tubules which pass uninterruptedly from one sarcomere to another. No transverse dilatations or T tubules are present as in ventricular cells; however, there are numerous subsarcolemmal cisterns consisting of flattened dilatations of sarcoplasmic reticulum which lie in close proximity to the internal surface of the sarcolemma. There is considerable variation from one cell to another in the number and compactness of arrangement of the myofibrils, and in the abundance of other cellular components.On the basis of the above findings, we suggest that atrial muscle cells may have a secretory as well as a contractile function.
Cytological aspects of trophoblast‐uterine interaction in early implantation
Authors: Enders Allen C. , Schlafke Sandra 
Published: February 2005

AbstractTrophoblast‐uterine epithelial cell interrelationships were studied using implantation sites from the rat, rabbit, guinea pig, armadillo, bat and ferret. It was found that in all species trophoblast cells extend over several epithelial cells at the apposition stage of implantation. Trophoblast can adhere to the apical ends of uterine epithelial cells by primitive junctional complexes. More surprisingly, in most species desmosomal junctions are formed between trophoblast and the lateral aspects of uterine epithelial cells by primitive junctional complexes. More surprisingly, in most species desmosomal junctions are formed between trophoblast and the lateral aspects of uterine epithelial cells by primitive junctional complexes. More surprisingly, in most species forms the complementary protion of the apical junctional complexes with the adjacent luminal epithelial cells. Certain basement membranes appear to be barriers to trophoblast invastion in some species but not in others. There is little evidence that trophoblast is cytolytic, whereas all of the trophoblast examined gave some evidence of phagocytic activity, and the trophoblast of some of the more invasive forms showed evidence of being histolytic.It is suggested that the capacity of trophoblast to form junctions with epithelial cells is an important part of the implantation process, facilitating penetration of the endometrium without dislodgment of the blastocyst.
Nucleoside phosphatase activity in atrial and ventricular myocardium of the rat: A light and electron microscopic study
Authors: Ferrans Victor J. , Hibbs Richard G. , Buja Louis M. 
Published: February 2005

AbstractNucleoside phosphatase activity was studied in glutaraldehyde‐fixed rat myocardium. At pH 7.2, ATPase, nucleoside diphosphatase and thiamine pyrophosphatase activity were demonstrated in the transverse elements of the sarcoplasmic reticulum of ventricular fibers and in the subsarcolemmal cisterns of atrial and ventricular muscle cells. The remainder of the sarcoplasmic reticulum of atrial and ventricular fibers showed reactions only with nucleoside diphosphates. The T tubules and intercalated discs of ventricular muscle reacted strongly with nucleoside monophosphates at pH 7.2; atrial myocardium showed this reaction only in the intercalated discs and in the spaces between closely apposed muscle cells.Thiamine pyrophosphatase and nucleoside diphosphatase were demonstrated in the Golgi apparatus of both atrial and ventricular muscle cells; however, reactive cisterns were more numerous in atrial than in ventricular myocardium. These enzymes were also demonstrated in some of the membranes surrounding the specific cytoplasmic granules of atrial muscle cells. Acid phosphatase activity was also detected in some of these membranes when cytidine monophosphate was used as substrate.
Ultrastructure of human yolk sac: Endoderm, mesenchyme, tubules and mesothelium
Authors: Hesseldahl H. , Larsen J. Falck 
Published: February 2005

AbstractThe ultrastructure of human yolk sacs obtained by hysterotomy or hysterectomy from the third to the eleventh week of pregnancy is described with reference to the endoderm, mesenchyme, endodermal tubules and mesothelium. During the fourth to the sixth week of pregnancy the endoderm proliferates to form cords of cells projecting into the mesenchyme. The endodermal cells contain abundant endoplasmic reticulum, glycogen and iron‐containing material. Various types of tubules in the endoderm are described. The mesenchymal cells vary in appearance; some are stellate with slender cytoplasmic processes, while others are round. A few show signs of phagocytic capacity. Both the endodermal and the coelomic epithelia possess microvilli and pinocytotic vesicles. A hypothesis relating to the function of the human vitelline endoderm is proposed.
Reactive dyes as vital indicators of bone growth
Authors: Seiton Elsa C. , Engel Milton B. 
Published: February 2005

AbstractCertain reactive dyes of the procion M and remazol group were effective for vital staining of growing bones. These compounds appear to form covalent bonds with the protein matrices and are preservedin situafter decalcification. Dye concentrations in sera of animals receiving one injection were followed. There was a precipitous drop in optical density in the first 24 hours; the remainder of the dye was largely cleared from the serum in 11–21 days. Dye concentrations and staining of bone were correlated. The width of the stained bone appeared to be related to rate of growth and disappearance of dye from the blood. On electrophoresis, the dyes moved with the albumin fraction. Dialysis and electrophoresis experiments favored the conclusion that they form covalent bonds with the protein. Growth of the rabbit mandible at 5–13 weeks, was studied by microscopy in decalcified sections. Using multicolored dyes, the sites of growth were marked in known sequence and sites of resorption were identified by interruption of stained zones. Principles of growth and remodelling advanced by Enlow were confirmed and the growth pattern of the rabbit mandible was elucidated.
Microscopy of the living pancreas in situ
Authors: McCuskey Robert S. , Chapman Thomas M. 
Published: February 2005

AbstractThe purpose of this investigation was to study the microscopic anatomy of the living pancreas in situ. The results indicate that: (1) it is possible to study cellular detail in the living pancreas with resolution closely approaching the limit of resolution of the light microscope; (2) blood flow through indivdual capillaries in both acinar and islet tissue is intermittent; (3) local blood flow through acinar capillaries is regulated by smooth muscle precapillary sphincters and by endothelial sphincters, while flow through capillaries in islets is regulated locally by endothelial sphincters only: (4) insular‐acinar capillary anastomoses exist but are not frequent; (5) secretory canaliculi between adjacent acinar cells exist in life and pass between centro‐acinar cells to reach the lumen of the ducts; (6) processes of beta cells may pass between two adjacent cells to provide additional surface area for transcapillary exchange; (7) the formation and release of zymogen granules occurs within 45‐90 minutes in acinar cells stimulated with pancreozymin and the formation and release of beta granules occurs within 20‐60 minutes in beta cells stimulated with tolbutamide; and (8) cytological changes during the secretory cycle in acinar and beta cells are consistent with the current ultrastructural theory of secretion.
Fine structure of the human menstrual corpus luteum at its stage of maximum secretory activity,
Authors: Gillim Stuart W. , Christensen A. Kent , McLennan Charles E. 
Published: February 2005

AbstractHuman corpora lutea from the period of maximum progesterone secretion during the menstrual cycle were examined with the electron microscope. Both the granulosa lutein and theca lutein cells contain abundant tubular smooth endoplasmic reticulum, mitochondria with tubular cristae, lipid droplets and numerous free ribosomes. Cisternae of rough endoplasmic reticulum occur in stacks and as scattered profiles in the lutein cells. Golgi elements are seen throughout the granulosa lutein cell cyoplasm and are associated with multivesicular bodies, lysosome‐like granules, coated vesicles and microtubules. The coated vesicles apparently arise from the Golgi cisternae. Unlike the granulosa lutein cells, theca lutein cells are generally smaller and darker, exhibit a wider range of cell densities, have a Golgi complex clustered at one nuclear pole, and their lipid droplets are extracted by tissue preparation. Patches of microvilli that protrude into the perivascular spaces and a peripheral, fibrillar terminal web are unique to the granulosa lutein cells. The perivascular macrophages correspond to the “K” cells of light microscopy. No cells in the theca externa or the central coagulum exhibit the fine structure of steroid‐secreting cells.The correlation of fine structure with function in human lutein cells is probably similar to that established for other steroid‐secreting cells. The role of the theca lutein cells in steroidogenesis by the human corpus luteum remains unresolved.
Atrioventricular node innervation in ultrastructural three dimensions
Authors: Thaemert J. C. 
Published: February 2005

AbstractAtrioventricular nodal tissue was obtained from a two‐week‐old mouse heart which was fixed with phosphate‐buffered osmium tetroxide, embedded in Epon 812, serially sectioned for both light and electron microscopy and stained with uranyl acetate. From study of electron micrographic montages of the first 115 serial sections of the most inferior portion of the atrioventricular node it was determined that the intercellular spaces of this portion of the node contain fibrocytes, bundles of collagen fibrils, capillaries and a plexus of unmyelinated nerve bundles which are insheathed by Schwann cells. Relatively large nerve bundles divide to form smaller ones, the vesiculated nerve processes of which make intimate contact with the sarcolemmae of nodal cells. These neuromuscular contiguities, on the basis of the physical interrelationships of their respective vesiculated nerve processes and nodal cells, exist in various forms. They may be categorized as follows: (1) individual vesiculated nerve processes which dwell in sarcolemma‐lined tunnels or in culs‐de‐sac inside the nodal cells; (2) individual vesiculated nerve processes which lie within shallow or deep grooves on the surfaces of nodal cells; (3) vesiculated nerve processes which remain part of a small bundle while dwelling in a groove on the surface of an individual nodal cell or in grooves on the surfaces of two or more nodal cells; and (4) small individual bundles of vesiculated nerve processes and their Schwann cell investments which reside within sarcolemma‐lined tunnels inside nodal cells. These neuromuscular contiguities are fully described and their significance is discussed in relation to the present status of the nature and organization of the postganglionic ramifications of the autonomic nervous system within the conduction system of the heart.
A quantitative description of the intestinal epithelium of the mouse
Authors: Hagemann Ronald F. , Sigdestad Curtis P. , Lesher S. 
Published: February 2005

AbstractThe use of combined cell kinetic, tritiated thymidine labeling and liquid scintillation counting techniques has permitted quantification of several intestinal epithelial cell parameters. Wet weight and/or whole intestinal values for the following were obtained in C57B1/6 mice. Crypts/mg wet weight of intestine numbered 855 in the duodenum (D), 892 in the jejunum (J) and 1164 in the ileum (I). Crypts were subdivided into proliferative cells with the following values being obtained: 1.6 × 105/mg (D), 1.6 × 105 (J) and 1.7 × 105 (I), and for nonproliferative cells, 1.1 × 105/mg (D), 1.1 × 105 (J) and 1.2 × 105 (I). A cell cycle analysis permitted the proliferative cells to be further subdivided, and the numbers of cells in G1, S, and G2 + M were determined.Division of the total number of proliferative cells by the mean cell generation time provided a value of 1.4 × 107 cells/hour for the cell production rate in the entire intestine. Division of cell production rate/mg by crypts/mg gave values for cell production rate/crypt of 15.2 cells/crypt/hour (D), 14.6 (J) and 11.2 (I).Epithelial cells per villus (J) numbered 3025, and there were 3.1 × 105 villous epithelial cell per milligram of jejunum. Division gave a value of 102 villi/mg (J). Dividing crypts/mg by villi/mg gave a value of 8.7 crypts/villus (J).Mean cell transit time from crypt to villus apex was 43.1 hours (D), 41.8 hours (J) and 42.6 hours (I).
Cytoarchitecture of the substantia nigra in the rat
Authors: Hanaway Joseph , McConnell Jo Ann , Netsky Martin G. 
Published: February 2005

AbstractMidbrains of ten young adult rats were sectioned serially in three planes to study the detailed cytoarchitecture of the substantia nigra. These neurons measure 8 to 17 μ in diameter. In comparison, the largest neurons in the midbrain measure 20 to 40 μ; hence, neurons are designated according to size as follows: those measuring 18 to 40 μ, large; 12 to 17 μ, medium; and 8 to 11 μ, small. The substantia nigra of the rat contains non‐pigmented neurons in three divisions: pars reticulata, pars compacta, and pars lateralis. The pars reticulata is the largest division and has the longest rostrocaudal extent. It contains neurons of small size medially and of medium size laterally. This finding correlates with described differences in connections. Three‐dimensionally, the pars reticulata is an oblate spheroid with the long axis in the rostrocaudal plane. The pars compacta is a triangular layer dorsal to reticulata. It is subdivided into rostral and caudal portions at the level of the fibers of the basal optic root. Neurons in both subdivisions are medium in size, but cells rostrally are darker than those caudally. The pars lateralis is a column of neurons with its long axis located in the rostrocaudal plane. It lies dorsolateral to the pars reticulata and the pars compacta, with occasional connections to both by cellular strands. The pars lateralis has rostral and caudal portions; neurons rostrally are medium in size and round; caudally, however, neurons are variable in size, dark, stellate or fusiform, and have long processes.
Electron microscope studies of frozen‐substituted marine eggs. I. Conditions for avoidance of intracellular ice crystallization
Authors: Rebhun L. I. , Sander G. 
Published: February 2005

AbstractEggs of the marine clam Spisula solidissima were examined by the technique of freeze‐substitution. Morphology of the cytoplasm was investigated as a function of cellular water content using osmotic means to control water concentration. In eggs frozen in less than double strength sea water, ice crystallization usually occurred throughout the cell. In eggs frozen in double to triple strength sea water, 10–75% of the eggs were devoid of ice crystals in the cytoplasm and in triple strength sea water, also in the nucleus. From these results and from a detailed analysis of cells in which both ice crystals and ice crystal‐free regions occurred it is concluded that cells or parts of cells may be frozen free of ice crystals if their free water content is reduced. Reduction in free water content may occur in several ways: deliberate dehydration by osmotic means; accidental dehydration by evaporation of water from cells prior to freezing; osmotic dehydration of one region by an adjacent one in which ice crystallization is in progress. In ice crystal‐free cells, all common cell inclusions could be recognized.
Electron microscope studies of frozen‐substituted marine eggs. II. Morphology of ice crystal‐free unfertilized eggs
Authors: Rebhun L. I. , Sander G. 
Published: February 2005

AbstractStudies of ice crystal‐free eggs of the clam Spisula solidissima using freeze‐substitution techniques are described. Formation of ice in cells may be avoided by removing sufficient intracellular water prior to freezing. After such treatment, most subcellular inclusions can be recognized and have dimensions similar to those seen after chemical fixation. Golgi regions, ribosomes, endoplasmic reticulum, nuclear envelope, annulate lamellae, yolk and the vitelline membrane resemble their counterparts in chemically fixed eggs. Mitochondria, however, lack the space normally found between cristae walls, and the resulting structure resembles two unit membranes “back to back.” Several inclusions and structures not seen in chemically fixed eggs are described: light bodies are found in groups of two to eight near the Golgi regions; cores occur in the microvilli of the vitelline membrane, microtubules are found in the cytoplasm of the unfertilized egg and 220 to 250 Å particles, which are not ribosomes, occur regularly arranged along microtubules.