bluuebunny/crossref_metadata_2025_split huggingface dataset:
The somatic chromosomes of the opossum (Didelphis virginiana)
Authors: Hoy William E. , George W. C. 
Published: February 2005

AbstractThere are eleven pairs of chromosomes in the somatic cells of the opossum.The sex chromosomes are of the x‐x type in the female and the x‐y type in the male.The number and type of the chromosomes are constant in the wide variety of tissues and organs studied, except that one dividing giant cell of the spleen showed an 8n number of chromosomes.The arrangement of the chromosomes in equatorial plates is that of an autosomal ring surrounding the centrally located sex chromosomes.
An embryological study of a special strain of deformed x‐rayed mice, with special reference to the etiology and morphogenesis of the abnormalities
Authors: Plagens George M. 
Published: February 2005

AbstractThis investigation consists of an extensive histological study of a special strain of abnormal x‐rayed mice, in an attempt to determine the embryonic origin and development of certain congenital abnormalities that are hereditary.The study shows that development of the x‐rayed strain is normal up to the thirteenth day after insemination, after which pathological structures appear in the form of blebs, hematomas, and thrombi. As a result of the formation of the blebs and hematomas a general condition is set up within the embryo which resembles that of thrombosis. The thrombi when formed exert a mechanical effect by crowding out the normal tissue. A chemical effect is also produced by the blood cells and fluid extravasated from the thrombus which penetrate into the forming tissues resulting in their perverted development. Thus the thrombi are the immediate factors causing the various regions of the body to be deformed.
The opercular apparatus of salamanders
Authors: Monath Thomas 
Published: February 2005

AbstractThe primitive structure of the salamander otic capsule (exemplified by Hynobius) includes both operculum and columella in the fenestra vestibuli and connection of operculum with suprascapsular cartilage by an “opercularis” muscle formed by levator scapulae. Larvae of Hynobiidae, Ambystomatidae, and Salamandridae have early development of columella and stilus, which are used in sound transmission via the suspensorium until the development of the operculum and its muscular connection with the shoulder girdle at metamorphosis. Hynobiids and ambystomatids show parallel trends toward reduction or fusion of the operculum and widening of the attachment area of the levator scapulae on the suprascapular cartilage, and some members of both families have lost the operculum.The Salamandridae have lost columella and stilus as adult structures, but extend the attachment of levator scapulae ventrally by a division resulting in attachment to the scapulocoracoid, probably as an adaptation for better reception and transmission of sound vibrations in terrestrial environments.The Plethodontidae differ strikingly in otic structure from the other families in having an operculum present in the larval stage and fused to columella, and in utilization of part of the cucullaris major as an “opercularis” muscle. These changes are probably the result of changes in orientation of the fenestra vestibuli. In plethodontids with aquatic larval stages the columella is retained as a sound‐transmitting element, but in many specialized forms it is reduced or absent.Close correlation of otic structures with ecology limits their use as evolutionary indicators in salamanders. However, the general pattern of otic structures in salamanders, and the magnitude of differences in this region seen in plethodontids, indicates that the latter are probably not derived from the salamandrids, but from a primitive salamander stock.
Histochemistry of the “sexual segment” granules of the male rattlesnake kidney
Authors: Burtner H. J. , Floyd A. D. , Longley J. B. 
Published: February 2005

AbstractThe histochemistry of the “sexual segment” granules of the kidney of male diamondback rattlesnakes has been studied to define the nature of these andro‐genically responsive granules. The kidneys were variously fixed and sections stained with a number of acid dyes, as well as by a variety of carbohydrate, lipid, and protein histochemical methods. The results indicate that “sexual segment” granules bind acid dyes strongly, contain some lipids and neutral glyco‐ or mucoproteins, much tyrosine and lysine, and some tryptophan and cysteine. A resemblance, concluded to be superficial, is noted between the histochemical properties of zymogen granules and the predominantly proteinaceous “sexual segment” granules.
The development of the skull of Psammophis sibilans. I. The development of the chondrocranium
Authors: Kamal A. M. , Hammouda H. G. 
Published: February 2005

AbstractThe development of the chondrocranium of the Egyptian snake, Psammophis sibilans has been thoroughly studied in six developmental stages. The neurocranium and viscerocranium develop at the same time. In early stages the mesocephalic flexure is well represented, but later it is gradually reduced. The notochord is completely embedded inside the parachordal plate in the early and moderate stages, and the paired origin of the plate is not observed. From the very beginning the quadrate cartilage is in close contact with Meckel's cartilage. In early stages the two cartilages lie nearly at the same straight line, and throughout development the quadrate rotates freely until the angle between it and Meckel's cartilage becomes nearly a right one. It was impossible to find a stage at which the auditory capsules and their cochlear portions were separate from the parachordal plate. There is no interorbital septum and the platytrabic character of the chondrocranium is preserved. The basicranial fenestra, fenestrae X and the fenestra ovalis are formed by the resorption of pre‐existing cartilage. The planum antorbitale has no separate center of chondrification. The rudiment of a simplified type of concha nasalis is formed in the last stage. The lamina transversalis anterior is formed of two separate portions. The tectum synoticum is of purely otic origin.
The hypophysis and hypothalamo‐hypophysial system in the chimaeroid fish Hydrolagus colliei (Lay and Bennett) with a note on their vascularization
Authors: Sathyanesan A. G. 
Published: February 2005

AbstractThe pituitary of Hydrolagus is divided into four parts: the rostral pars distalis, the proximal pars distalis, neurointermediate lobe and an oral or pharyngeal component the Rachendachhypophyse. The Rachendachhypophyse may be comparable to the ventral lobe of elasmobranchs, in their position, histology and post‐ embryonic structure. A well defined hypothalamo‐ hypophysial neurosecretory system demonstrable with aldehyde fuchsin is present. The nucleus lateralis tuberis is long and seems to extend from the posterior region of the optic chiasma to the median eminence. The nucleus preopticus is situated anterodorsal to the optic chiasma. The bulk of the neurosecretory axons enter the neurointermediate lobe and have perivascular endings. At least some axons seem to terminate in median eminence, and this region is intimately connected with the pars distalis by a network of capillaries, suggesting the presence of a hypothalamo‐ hypophysial portal system. The presence of median eminence and hypothalamo‐ hypophysial portal system in elasmobranchs, and its apparent occurrence in Hydrolagus, seem to necessitate modification of earlier views concerning the phylogenetic derivation of the tetrapod neurohypophysis.
Hypothalamo‐neurohypophysial system in the normal and hypophysectomized teleost Porichthys notatus girard and its response to continuous light
Authors: Sathyanesan A. G. 
Published: February 2005

AbstractThe teleost Porichthys notatus has a long infundibular stalk measuring about 3 to 5 mm or more in the adult. The infundibular recess extends into the stalk in the form of a long infundibular funnel. The hypothalamo‐hypophysial system is typical of the teleosts. In the hypophysectomized fish where there was no regeneration or reorganiation of the infundibular stalk, aldehyde fuchsin‐positive substance progressively increased in quantity in the cell bodies of the preoptic nucleus. When these specimens were subjected to continuous light for 15 days, the staining intensity of the cells of the preoptic nucleus diminished, but greater accumulation of AF‐positive substance was noticed along the axonal pathway and in the infundibulum. This suggests that light might act as an activating agent causing the dispersal of the accumulated neurosecretory material from the cells along their axons.
The blood vessels of the regenerating limb of the adult newt, Triturus
Authors: Peadon Annie M. , Singer Marcus 
Published: February 2005

AbstractThe vessels of the forelimb stump and regenerate were perfused with Prussian blue and studied as whole mounts and in histological sections to reveal the condition and disposition of the blood vessels in various stages of forelimb regeneration in the adult newt, Triturus viridescens. The development of the vessels in the regenerate seemed to be comparable in all its essential features to that which has been described for the normal developing limb in urodele, chick and pig embryos.The first signs of regeneration of the vessels are seen during wound healing when fine sprouts appear from the old vessels near the amputation wound. These grow and anastomose, but are limited to the transition region between old and new tissues and avoid the growing blastema during the early stages of regeneration. As the regenerate enlarges into a conical structure vessels invade the proximal part of the growth and avoid the distal regions. It is only during the stages of histogenesis and morphogenesis that vessels grow into more distal regions. The regions of most active enlargement of the early or later regenerate are those most poorly vascularized. These results are discussed against the background of the activity of certain enzymes during regeneration. In the advanced regenerate, preferential channels are consolidated until in the palette and digital stages the pattern of the blood vessels resembles that of the normal limb.
Some histochemical observations on the effects of chorioallantoic grafts on the spleen, bursa, and peripheral blood of chicken embryos
Authors: Fennell Richard A. 
Published: February 2005

AbstractHatching eggs from inbred lines of chickens (inbreeding coefficient exceeds 95%) which show various degrees of resistance and susceptibility to Rous sarcoma, were used for experimentation. Adult tissues were grafted onto the chorioallantois on the tenth day of incubation and tissues of host and control embryos were harvested on the twentieth day of incubation. Enzymes were localized in tissues by histochemical procedures.Small pieces of tissue (thymus or bursa), when grafted onto the chorioallantois, increased the size of the spleen in host embryos although splenomegaly did not invariably occur. Two types of reactions were observed in the spleen, i.e., enlarged spleens with cysts or enlarged spleens which from a morphological point of view were normal. Grafts of either thymus or bursa decreased the size of the host embryo's bursa or were without effect. When weight of the bursa of host embryos was significantly less than that of control embryos on the twentieth day of incubation, this size relationship persisted in chicks four weeks post hatching.Intensity of dehydrogenase and acid phosphatase reactions in cysts of enlarged spleens and in the multinucleated giant cells investing them suggests that they consist of groups of degenerating cells. Intensity of enzyme reaction indicates that enlarged spleens of host embryos in which cysts were absent were normal. Enzyme reactions in the bursae of experimental embryos were more intense than those identified in the same tissues of control embryos. Catabolic reactions were the predominant type in grafts ten days subsequent to implantation. Grafts increased the number of erythrocytes in the peripheral blood of host embryos.
The diencephalon of the primitive bony fish Polypterus in the light of the problem of homology
Authors: Nieuwenhuys Rudolf , Bodenheimer Thomas S. 
Published: February 2005

AbstractThe diencephalon of Polypterus can be divided into an epithalamus, thalamus, and hypothalamus. The habenulae, the nervous parts of the epithalamus, are comparable to their homologues in other lower vertebrates with respect to sulcal boundaries, cellular structure, and fiber connections. The thalamus of Polypterus is not divisible into a pars dorsalis and pars ventralis by the sulcus medius; rather this sulcus is in the middle of a uniform, laminated cytoarchitectonic field. In this respect Polypterus differs from other species in whom the sulcus medius divides the thalamus into dorsal and ventral parts. There are six migrated nuclei in the thalamus of Polypterus. There is only one circumscribed projection into the thalamus, i.e., the optic tract, but there are numerous diffuse fibers terminating in this region of the brain. The hypothalamus, except for a partially migrated nucleus, has retained the periventricular arrangement of cells. It has large fiber connections with the forebrain and brainstem.The literature on the diencephalon of lower forms has been reviewed with special emphasis on the question of how homologies are established in this brainpart. It appeared that three different criteria, either singly or in combination, have been employed as a clue to identification of structures in the diencephalon. These are, (1) ventricular grooves, (2) nuclear boundaries, and (3) fiber connections. In order to test the practical validity of these criteria the diencephalon of Polypterus was compared to that of five related species, i.e., the actinopterygians Acipenser and Polyodon, the dipnoans Protopterus and Neoceratodus, and the crossopterygian Latimeria. In addition three amphibians, Necturus, Ambystoma and Rana, were involved in our comparative considerations. It was concluded that, within the confines of the diencephalon of the species mentioned, cytoarchitectural differences form the most valid criterion for establishing homologies. The drawback and restrictions connected with the use of ventricular sulci and fiber connections, as a clue to identification have been evaluated and discussed.
Some cytologic characteristics of the hemocytes of Limulus during clotting
Authors: Dumont James N. , Anderson Everett , Winner Gillian 
Published: February 2005

AbstractThe hemolymph of the horseshoe crab, Limulus (Xiphosura) polyphemus, contains a single cell type. The hemocytes are ovoid and contain many refractile granules. One‐half to one minute after the onset of clotting the hemocytes swell and a hyaline cytoplasmic ring, essentially devoid of granules, appears about their circumference. During this time the granules disperse and the nucleus becomes visible. Three to five minutes following the initiation of clotting, the cell extends long pseudopodial processes. Phase contrast time‐lapse cinematography reveals that the cells are extremely motile during this phase. Concomitant with these changes, many of the granules lose their refractility and one by one disappear from the cytoplasm leaving what appears to be a vacuole.Electron micrographs of native (un‐clotted) hemocytes and of clots fixed in glutaraldehyde and post‐fixed in osmium reveal that the membrane‐bounded granules of native cells are very dense and homogeneous with no evidence of an internal structure. One‐half to one minute after clotting, however, they become less dense and 250 Å microtubules spaced at ca. 500 Å intervals appear parallel to the long axis of the granule. Further degradation of the granule ensues and involves (a) change to a spherical shape, and (b) further decrease in density and better resolution of the microtubules. The microtubular component subsequently disintegrates leaving a membrane‐bounded granule containing particulate material. Finally, the membrane of the granule fuses with the plasma membrane and the components of the granule are dispersed in the plasma where they presumably contribute to the formation of the gelatinous clot.
The development of the musculature of the hindlimb in the frog, Rana pipiens
Authors: Dunlap Donald G. 
Published: February 2005

AbstractThe major features of the morphogenesis of the muscles of the hindlimb, exclusive of the foot, are described and illustrated for the frog, Rana pipiens The description is carried through the stage XII larva, in which stage most of the muscles of the adult limb are present in essentially the definitive condition. As is true of other vertebrates which have been studied, the muscles of the hindlimb develop from two major premuscular masses. One of these lies along the dorsolateral margin of the limb and the other along the ventro‐medial margin. Each of the two masses is subsequently divided into smaller and smaller subdivisions as the different muscle groups and the individual muscles are differentiated. In general, the more proximally located muscles differentiate before those which are located more distally and those of the dorso‐lateral mass before those of the ventro‐medial mass.The following muscles of the thigh, shank and tarsus develop from the dorsolateral mass: ileo‐fibularis, glutaeus magnus, cruralis, ileo‐femoralis, iliacus externus, iliacus internus, tensor fasciae latae, pectineus, adductor longus, peroneus, tibialis anticus brevis, tibialis anticus longus, extensor cruris brevis, tarsalis anticus, extensor digitorum communis longus and abductor brevis dorsalis. The following develop from the ventro‐medial mass: compressor cloacae, circumflexor arteriae, pyriformis, semimembranosus, gemellus, gracilis major, gracilis minor, semitendinosus, adductor magnus, obturator internus, obturator externus, quadratus femoris, sartorius, plantaris longus, tibialis posticus, tarsalis posticus, plantaris profundus, intertarsalis and flexor digitorum brevis superficialis.
The fine structure of blood cells in the ascidian Perophora viridis
Authors: Overton Jane 
Published: February 2005

AbstractThe fine structure of each of the blood cell types of Perophora viridis has been characterized and strong evidence for localization of vanadium in two of these types is given.There are eight cell types; phagocytes which may contain completely engulfed cells, lymphocytes with a prominant nucleolus and scanty cytoplasm packed with clustered ribosomes, and six other cell types each with distinctive granules. Morula cells contain a central nucleus and cytoplasm filled by wedged bodies, about five of which are seen in section. These bodies contain regularly spaced electron dense foci. Green cells have the same organization but contain bodies which are electron dense throughout. Granular amoebocytes contain many smaller lightly staining oval bodies and much glycogen. Another cell type (probably orange cells of light microscopy) contains numerous granular rounded bodies. Compartment cells have vacuoles containing electron dense particles and signet ring cells have usually one large vacuole which is electron dense lined and may contain electron dense particles. Developmental stages of these cell types show involvement of endoplasmic reticulum and Golgi bodies in granule formation.After glutaraldehyde fixation alone the only extremely electron dense components are particles in the compartment cells and signet ring cells implicating these as sites of vanadium localization, although not excluding other cell types.
The effect of molting upon the vibration receptor of the spider (Achaearanea tepidariorum)
Authors: Walcott Charles , Salpeter Miriam M. 
Published: February 2005

AbstractThe physiology and fine structure of the vibration receptor of the spider (Achaearanea tepidariorum) was studied throughout the process of molting. The physiological studies showed that there is no dramatic change in the receptor's vibration sensitivity as the time of ecdysis approaches. Only a gradual loss of sensitivity can be detected on a statistical basis using large numbers of spiders. The fine structural studies suggest that the connection between the sensory neurone and the receptor within the old cuticle remains intact up to the time that the cuticle is shed.
Embryonic development of the ciliary arteries of the rabbit from inception through the emergence of the circulus arteriosus iridis
Authors: Strong Leon H. 
Published: February 2005

AbstractSince the rabbit's eye more nearly resembles the human eye than any other mammal used in experimental investigations, a detailed study of its ciliary arteries has been made. A closely timed series of embryos injected through the living umbilical vein and rendered transparent show, in thick sections, silhouetted vessels in perspective. Heretofore the ciliary arteries have been studied from their first identification until they have reached the primitive choriocapillaris, but no farther. This study shows their complete history including their relation to the circulus arteriosus iridis major and to the pupillary membrane. Our special concern has been ferreting out the mode of migration of the components of the definitive arteries. New findings include: (1) an arteriovenous plexus which mediates the transference from vessels anastomotic with it to other such vessels; (2) functionally different segments of the primitive ciliary arteries; (3) different arterial and venous plexuses which play roles in embryonic development; (4) discovery of the realignment of the choriocapillaris into vertical vessel meshes with transverse anastomoses between them, each of which have different fates; (5) the mode of development of the circulus arteriosus iridis major; (6) a crown of venous vessels looping around the iris margin; and (7) a special arterial supply for the ciliary processes.
Number of nucleoli in various cell types of the mouse
Authors: Shea J. R. , Leblond C. P. 
Published: February 2005

AbstractThe nucleoli of cells of the adult mouse were examined by staining with toluidine blue after removal of deoxyribonucleic acid from tissue sections by deoxyribonuclease treatment.The nuclei of each cell type examined contained one or more nucleoli. This was observed even in lymphocytes and neuroglia, although these cells have occasionally been described as anucleolated. In mature spermatids and spermatozoa, however, it was not possible to detect a nucleolus.The distribution of the number of nucleoli in many diploid cells exhibited a mode of two or three nucleoli per nucleus, and a range from 1 to 6 nucleoli.In presumedly diploid hepatic nuclei, the maximum number of nucleoli was six; but in presumedly tetraploid hepatic nuclei, it was 11. Thus, nearly twice as many nucleoli are present when the chromosome number is doubled. In view of this observation, it is suggested that six nucleolar organizers are present in the diploid chromosomal complement of the mouse. However, through failure of some nucleolar organizers or more probably through fusion of nucleoli, the number of these organelles in most nuclei is less than six.