bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tensile forces in skeletal structures
Authors: Oxnard Charles E. 
Published: February 2005

AbstractRecent hypotheses about the mechanisms of adaptation of bone to impressed mechanical forces differ according to the extent to which tensile stresses are thought to be functionally important in bone. A pilot study of three anatomical regions by means of the photoelastic analogy suggests the possibility that net tension rarely exists in significantly large regions of bones during normal function.Thus the examination of two situations (opposite linear attachment of muscles to the lips of bony crests and opposite areal attachment of muscles to either side of thin bony plates) suggests that in rare cases where precise anatomical architecture is such that net tension may be present, then bone is not found; such regions consist of appropriate collagenous structures.In the third situation (opposite attachment of tendons to a sesamoid bone) where it would appear that net tension ought to exist, it is suggested that it is likely that it does not. Net tension probably occurs only in tendons running in tightly curved bony grooves: those very situations where sesamoid bones are not present.
The regeneration of caudal epidermal specializations in Lygodactylus picturatus keniensis (gekkonidae, Lacertilia)
Authors: Maderson P. F. A. 
Published: February 2005

AbstractThe epidermal covering of the tail scales of the gekkonid lizard Lygodactylus bears three distinct types of specialization: sense organs, pilose pads whose function is either sensory or scansorial or both, and holocrine secretory organs (β‐glands) which are only found in males. The same specializations are found on regenerated tails, and although the morphological form and patterning of the scales do not resemble the original, the structure, distribution and sexual specificity of the specialized units is perfectly restored. These structures, and similar units in other lacertilian genera have certain resemblances to mammalian and avian epidermal specializations. Perfection of replacement of integumentary specializations can be correlated with functional demands, although the developmental mechanism underlying the phenomenon is unknown.
Histochemistry of the epithelial mucins in the alimentary tract of the snail Marisa cornuarietis
Authors: Demian Emile S. , Michelson Edward H. 
Published: February 2005

AbstractA histochemical study of the mucus‐secreting cells in the epithelial lining of the alimentary tract of the ampullariid snail Marisa cornuarietis permits description of six types of glandular cells secreting carbohydrate‐rich substances. These mucous cells are designated on morphological grounds as fusiform, club‐shaped, ovate, goblet, saccular and elongated conical and their histology together with their distribution and relative frequency in the different organs is described.Histochemical analysis using various fixatives and numerous recently‐developed histochemical techniques shows that four main types of mucosubstances are produced by the six cell types. (1) The fusiform and club‐shaped cells secrete neutral mucosubstances with moderate‐to‐weak PAS reactivity and variable amounts of basic protein. (2) The ovate cells secrete a strongly PAS‐reactive, neutral mucosubstance lacking associated basic protein. (3) The goblet and saccular cells elaborate predominantly PAS‐unreactive, strongly acidic, and highly sulfated mucosubstances or sulfomucins. (4) The elongated‐conical cells secrete a highly PAS‐reactive, weakly acidic sulfomucin whose vic‐hydroxyls are presumably located in close proximity to sulfate esters.
Hemopoietic tissue in the adult newt, Notopthalmus viridescens
Authors: Hightower James A. , Pierre Ronald L. St. 
Published: February 2005

AbstractThe presence of developmental stages of lymphocytes and their precurors, as revealed by serial and thin sections of hemopoietic organs of normal adult newts (Notopthalmus viridescens) suggests that lymphopoiesis is limited to the thymus, medulla of the spleen and, to a lesser degree, the intestine. Stromal cells, small lymphocytes, granulocytes, mature erythrocytes and melanocytes were observed either within or near the parenchyma of the thymus. The urodele thymus differs from the thymus of anurans and higher vertebrates in that it lacks a cortex and a medulla, myoid cells and Hassall's corpuscles.
Hemocytoblastoid reaction of thymic subcapsular cells to diphtheria toxoid
Authors: Sainte‐Marie G. 
Published: February 2005

AbstractSubcapsular cells lining the thymic stroma vary from low to high forms, while others have a hemocytoblastoid aspect. The purpose of the present study was to establish whether the transformation of the low forms into hemocytoblastoid subcapsular cells can be induced by an antigen. Rats given 10 Lf of diphtheria toxoid intramediastinally were killed at periods ranging from 3 to 24 hours later. Other rats were injected with 3H‐thymidine at various intervals after the toxoid injection, and were killed one hour later. The observations revealed a rapid hemocytoblastoid transformation of subcapsular cells following administration of the toxoid. The transformation is detectable as early as three hours after the injection and can be completed after nine hours. Radioautography revealed that DNA duplication is initiated rapidly in the transforming subcapsular cells, since it can be completed 9 to 12 hours after the toxoid injection. Other observations suggested the transformation of reactive perithymic fibroblasts into subcapsular cells as well as the transformation of hemocytoblastoid fibroblasts and subcapsular cells into free hemocytoblastoid cells.
The fine structure of an absorptive epithelium in a viviparous teleost
Authors: Mendoza Guillermo 
Published: February 2005

AbstractEmbryos of the viviparous teleost, “Characodon” eiseni, have unusual anal processes that function only during gestation and are lost shortly after birth. This study was undertaken to determine if the fine structure of the process epithelium supports the assumption that these cells have an absorptive function. The process epithelium is a single layer of columnar cells. At peak activity intercellular spaces become very large and isolate individual cells which simultaneously lose much of their cell mass. The cells are characterized by microvilli on their free surface, much pinocytic activity and by the formation of at least four different kinds of vesicles. There is much evidence that these vesicles fuse together. A distinctive characteristic of these cells is a system of tubules and flattened cisternae that somewhat resemble the endoplasmic reticulum yet they differ from it in several respects. It is suggested these profiles aid in fragmenting the cell at periods of peak absorptive activity, thereby increasing the cell surface. Possible mechanisms of food absorption are considered. The fine structure of these cells supports the contention that these embryonic processes serve as absorptive organs during gestation.
The tracheae of water mites
Authors: Mitchell Rodger 
Published: February 2005

AbstractThe water mites of standing waters have evolved a novel respiratory system consisting of numerous independent tracheae of tracheolar dimensions. Each trachea has a portion of its length lying directly under the cuticle and one or both ends of the trachea turn into the body to supply some organ. There is no fusion of tracheae to form trunks. Areas of dense tracheation dorsal to the legs supply the leg muscles, and sometimes there is a distinct area of the venter that supplies the muscles of the mouthparts.
Studies on the neurosecretory system and retrocerebral endocrine glands of Nezara viridula Linn. (Heteroptera: Pentatomidae)
Authors: Awasthi V. B. 
Published: February 2005

AbstractThe neurosecretory system and retrocerebral endocrine glands of Nezara viridula Linn. have been described on the basis of in situ preparations and histological sections employing the paraldehyde fuchsin (PF) and performic acid‐victoria blue (PAVB) techniques.In the brain of N. viridula, there are two medial groups–each consisting of five neurosecretory cells which belong to A‐type. The lateral neurosecretory cells are absent. The axons of the two groups of medial neurosecretory cells (MNC) compose the two bundles of neurosecretory pathways (NSP) that decussate in the anterodorsal part of the protocerebrum. The two pathways, after the cross‐over, run deep into the protocerebrum and deutocerebrum and emerge as NCC‐I from the tritocerebrum. The nervi corporis cardiaci‐I (NCC‐I) of each side which are heavily loaded with NSM terminate in the aorta wall. Thus, the neurosecretory material (NSM), elaborated in the medial neurosecretory cells of the brain, is stored in the aortic wall and nervi corporis cardiaci‐I (NCC‐I). The NCC‐II are very short nerves that originate from the tritocerebrum and terminate in the corpora cardiaca (CC) of their side. Below the aorta, but dorsal to the oesophagus, lie two oval or spherical corpora cardiaca. A corpus allatum (CA) lies posterior to the corpora cardiaca (CC). The corpora cardiaca do not contain NSM; only the intrinsic secretion of their cells has been occasionally observed which stains orange or green with PF staining method. The corpus allatum sometimes exhibits PF positive granules of cerebral origin. A new connection between the corpus allatum and aorta has been recorded. The suboesophageal ganglion contains two neurosecretory cells of A‐type which, in structure and staining behaviour, are similar to the medial neurosecretory cells of the brain. The course and termination of axons of suboesophageal ganglion neurosecretory cells, and the storage organ for the secretion of these cells have been reported. It is suggested that the aortic wall and NCC‐I axons function as neurohaemal organ for cerebral and suboesophageal secretions.
Evolutionary morphology of the caecilian urogenital system. IV. The cloaca
Authors: Wake Marvalee H. 
Published: February 2005

AbstractThe gross and microscopic anatomy of male and female cloacae of caecilians (Amphibia: Apoda or Gymnophiona) is described and analyzed in terms of structure and function. The arrangement of musculature and cloacal accessory structures is species‐specific in males. Contraction of certain cloacal and body wall musculature facilitates eversion of the male cloaca for use as an intromittent organ. The cloacae of females show less marked morphological differences from species to species, and are modified as receptors of male phallodea.
Histological and histochemical studies of post‐ovulatory and pre‐ovulatory atretic follicles in Mustelus canis
Authors: Tewinkel Lois E. 
Published: February 2005

AbstractThe atresia of post‐ovulatory and pre‐ovulatory follicles of the viviparous smooth dogfish, Mustelus canis, is compared for approximately the first fourth of an 11 month gestation. A thick collagenous sheath and numerous tubules in the theca identify the large, folded stage A post‐ovulatory follicle. In stage B the tubules have been filled by cells to form “islands.” In stage C the entire structure is greatly diminished, adjacent islands tend to fuse, the collagenous sheath is virtually gone and the granulosa is degenerating. Preovulatory follicles from large, yolky oocytes pass through four stages beginning with yolk phagocytosis by granulosa cells of the villi (stage I), which are long and granular in stage II; villi fuse, theca cells increase greatly, fill with granules (stage III), encroach on the granulosa and disperse it into small groups of cells which finally disappear (stage IV) leaving a mass of thecal cells. A special type of pre‐ovulatory follicle from small non‐yolky oocyte atresia exhibits prominent thecal tubules and an unusual arrangement of granulosa cells. This follicle appearrs to enlarge during the summer, becoming multilobed; few granules are present.The distribution of lipid in frozen sections, stained by Oil red O, is described for all types of follicles. Schultz and Lewis and Lobban tests for steroids were made on frozen sections with corresponding results. Positive green tests indicating the presence of steroids or possible steroidogenesis were limited to: (1) one post‐ovulatory follicle, in the islands; (2) four stage III and seven late stage IV pre‐ovulatory yolky atretic follicles; (3) two special atretic follicles. The special atretic follicle appears to be a unique feature of M. canis and it is suggested tentatively that it may be related to viviparity.
A comparison between the dermal glands in two insects Rhodnius prolixus (Hemiptera) and Calpodes ethlius (Lepidoptera)
Authors: Lai‐Fook Joan 
Published: February 2005

AbstractThe results of histochemical tests performed on the type “B” dermal gland in Rhodnius and the Verson's gland in Calpodes at different stages in their secretory cycle are presented. The secretions of both glands are slightly acidic sulphated mucosubstances. They differ in their main carbohydrate component which in Rhodnius is hyaluronic acid and in Calpodes is sialic acid. The glands, though structurally similar, differ in size, number, and development.
Muscular control of the vocal tract during release signaling in the toad Bufo valliceps
Authors: Martin William F. , Gans Carl 
Published: February 2005

AbstractThe release vibration and release call of Bufo valliceps have been studied by electromyography of the muscles involved, coupled with pressure and sound recording. The sequences are powered by contraction of the muscles of the body envelope and with the energy transmitted via the compressed pulmonary contents. Each pulse of a call starts as the laryngeal muscles relax and pulmonary pressure forces the arytenoid cartilages apart. Sound emission ceases when the laryngeal dilators pull the arytenoids out of the airstream. Reverse flow of air from buccal cavity to lungs may occur within prolonged release sequences. Inflation of the vocal sac results in marked increase in amplitude of the radiated sound without equivalent increase in amplitude of the myograns. The call is intimately associated with the pulsepumping method of breathing used by frogs.
The facial musculature of the suoidea
Authors: Herring Susan W. 
Published: February 2005

AbstractThe facial musculature and rhinarial anatomy of a tayassuid, Dicotyles, and four suids, Sus, Hylochoerus, Phacochoerus and Babirussa, are described. Differences found include the lack of m. zygomaticus in Hylochoerus and Phacochoerus and several modifications of the rostral muscles, mm. levator rostri, dilator naris, and depressor rostri. These differences are related to behavioral characteristics of the animals, particularly the occurrence of toothbaring and rhinarial mobility.The missing m. zygomaticus and relatively small mouth of Hylochoerus and Phacochoerus are probably associated with behavioral patterns which do not necessitate a large gape. In these genera the canines are exposed even when the mouth is closed. The development of the rostral musculature is correlated with movements of the rhinarium. Similarly, the distribution of terminal tendons depends on the shape of the nostril. In Hylochoerus and Phacochoerus, mobility of the rhinarium, especially the dorsal part, is less than in other suoids because of the firmer attachment of the rostral bone to the skull and the weaker development of the rostral muscles.
Morphology of the nasal fossae and associated structures of the hamster (Mesocricetus auratus)
Authors: Adams Donald R. , McFarland L. Z. 
Published: February 2005

AbstractThe hamster nasal cavity consists of vestibular, non‐olfactory and olfactory portions. Much of the non‐olfactory nasal cavity surface is lined by cuboidal, stratified cuboidal, and low columnar epithelia, devoid of cilia. Goblet cells and ciliated respiratory epithelium are present over only a small portion of the nasal cavity surface.The largest glandular masses in the hamster nose are the maxillary recess glands, the vomeronasal glands and the lateral nasal gland 1; these three glands contain neutral mucopolysaccharides (PAS‐positive). Other nasal glands contain both acidic and neutral mucopolysaccharides; the staining reaction for acidic mucopolysaccharide is stronger in goblet cells and olfactory glands than in the other nasal glands.The ducts which open into the nasal vestibule are the excretory ducts of compound tubuloacinar serous glands. The one major PAS‐positive gland whose duct opens into the nasal vestibule is the lateral nasal gland 1. The ducts of the compound tubuloacinar vomeronasal glands open into the lumen of the vomeronasal organ, which is connected to the ventral nasal meatus by means of the vomeronasal duct. The ducts of the branched tubuloacinar maxillary recess glands open into the maxillary recess. Few ducts open into the caudal half of the nasal cavity.
DNA synthesis, mitosis and fusion of myocardial cells
Authors: Przybylski Ronald J. , Chlebowski Joan S. 
Published: February 2005

AbstractMyocardial cells obtained from embryonic chick ventricles have been used to investigate (1) whether differentiated cells can undergo DNA synthesis and mitosis and, (2) whether heart cells when grown in culture can fuse with each other and with chick skeletal myoblasts to form heterokaryon myotubes. Electron microscopic observations have shown that myocardial cells of day 3 and day 20 chick embryos did contain myofibrils with defined sarcomeres; these cells have been observed in mitosis. Cells obtained by tryptic digestion of day 12 chick ventricles when grown in culture continued to replicate their DNA as shown by thymidine‐3H radioautography with DNase controls and were observed in all stages of mitosis. Electron microscopy showed that myofibrils were present in some of the cultured cells.Bi‐, tri‐ and tetranucleate cells were observed in the cultures. Thymidine‐3H radioautography showed that these cells were formed by karyokinesis without cytokinesis and by the fusion of uninucleate cells. Since the heart cells could fuse with each other, we tested the possibility that they could fuse with skeletal myoblasts to form heterokaryon myotubes. This was accomplished by co‐culturing thymidine‐3H labeled ventricular cells and unlabeled skeletal myoblasts. Radioautography with DNase controls showed that some of the myotubes consisted of unlabeled skeletal muscle nuclei and labeled heart nuclei in varied proportions. The factors initiating the formation of these heterokaryons have not been elucidated.
Nucleolar organization in oocytes of gryllid crickets: Subfamilies gryllinae and nemobiinae
Authors: Allen E. R. , Cave M. D. 
Published: February 2005

AbstractA cytological and cytochemical survey was made of nucleolar changes during oocyte development in several different species of crickets (Gryllidae) representing the subfamilies Gryllinae and Nemobiinae. A large mass of extrachromosomal DNA is characteristic of the pachytene stage nuclei of all species examined. Nucleolar material accumulates at the periphery of the DNA body as the cells proceed into the diplotene stage of development. As the oocytes proceed through diplotene, the nucleoli reorganize into many small masses which eventually disperse in the nucleoplasm. These changes reflect both an increase in number and in size of the nucleolar material during the diplotene stage and the mode by which dispersal of nucleolar material is accomplished. These differences probably reflect differences in the organization of extrachromosomal nucleolar DNA.
Analysis of the developing avian glycogen body. I. Ultrastructural morphology
Authors: Matulionis Daniel H. 
Published: February 2005

AbstractAn electron microscopic study of several stages in the development of the glycogen body of the chick is reported. During early developmental stages (7.5–11 days) glycogen granules were scattered throughout the cytoplasm of glycogen‐body cells. Lysosomes were observed for the first time on the eleventh day of incubation. In the course of subsequent development three well demarcated cytoplasmic areas became recognizable; a juxtanuclear region that contained most of the organelles and was devoid of glycogen, a peripheral area (ectoplasm) free of glycogen, and a region densely packed with glycogen. Cells that were heavily laden with glycogen contained unusual rounded or “C”‐shaped multivesicular bodies which were associated with the Golgi complex and with Golgi‐like vesicles. Their functional significance did not become evident in this descriptive study.The paucity of smooth endoplasmic reticulum indicated its lack of importance in glycogen metabolism in the glycogen body. Ribosomes, which were the only organelles consistently observed in close proximity to glycogen granules, were thus implicated in glycogen synthesis.
The fate of the normal‐anucleated spermatozoa in inseminated females of the silkworm Bombyx mori
Authors: Friedländer M. , Gitay H. 
Published: February 2005

AbstractBoth typical (haploid) and atypical (anucleated) spermatozoa reach the receptaculum seminis of inseminated females of Bombyx mori intermingled. However, only typical spermatozoa both leave the receptaculum and fertilize the eggs. Atypical spermatozoa, which are in fact anucleated flagellar apparatuses, probably function in transporting typical fertilizing spermatozoa to the receptaculum seminis. In the male ejaculatory duct both kinds of spermatozoa are wrapped with extra‐cellular sleeves that presumably protect them on their way to the receptaculum. Typical spermatozoa “hatch” from the sleeves before leaving the receptaculum to fertilize the eggs. The presence of a centriole in the extra‐testicular spermatozoa of this species supports the generalization that insect spermatozoa do have a centriole at the base of the flagellum.
Embryology of the sheep. I. Extraembryonic membranes and the development of body form
Authors: Bryden M. M. , Evans Howard E. , Binns Wayne 
Published: February 2005

AbstractThe developmental anatomy of the sheep in the early prenatal period (14 to 34 days) was studied using embryos of known coital age, and embryos of known size with estimated coital age. Characteristics of the embryos were studied by gross observation under the dissecting microscope, and by means of serial sections. The period of the ovum (from conception to 10 days) and the early embryonic period (from 11 to 14 days) are summarized from the literature.This work provides a detailed, systematic account of embryonic development in the sheep and establishes size‐age standards. Anatomical features encountered in the normal development of the sheep embryo are documented day‐by‐day because they are essential for studies of teratogenesis and early prenatal mortality.
Skeletal morphology of the mud star, Ctenodiscus crispatus (Echinodermata: Asteroidea)
Authors: Turner Richard L. , Dearborn John H. 
Published: February 2005

AbstractThe morphology of the following eight major ossicle types is described and illustrated for the goniopectinid asteroid Ctenodiscus crispatus: terminal plates, superomarginal and inferomarginal ossicles, adambulacral and ambulacral ossicles, odontophores, oral intermediate plates, and superambulacral ossicles. Development, variation, and relationships with soft body‐parts and with other ossicles are embphasized. Each ossicle type is distinguished by numerous structures related to its function and to articulation with adjoining skeletal elements. Because major structures (such as pustules, alveoli, and articulation surfaces) distinguishing ossicle types develop early during ontogeny, immature ossicles are readily identifiable. However, changes in form and orientation of these structures occur during ossicle growth. Ontogenetic changes are influenced by development of associated skeletal and soft parts. Ambulacral and adambulacral ossicles near the peristome are highly modified but retain the basic characteristics of structure and orientation which define these major types of skeletal elements.