bluuebunny/crossref_metadata_2025_split huggingface dataset:
Patella of selected bats: Patterns of occurrence or absence and associated modifications of the quadriceps femoris tendon
Authors: Smith Bonnie J. , Holladay Steven D. , Smith Stephen A. 
Published: February 2005

AbstractBackground: Having observed the apparent absence of a bony patella in a Madagascar flying fox (Pteropus sp.), other species from the two suborders of bats (Megachiroptera and Microchiroptera) were examined to determine the presence or absence of a bony patella and the distribution of this feature among bats.Methods: Gross, radiographic, and histologic examination of seven megachiropteran species representing four genera, as well as six microchiropteran species representing six genera, was performed.Results: A bony patella was observed in all six microchiropteran and in three megachiropteran species. The tendon of the quadriceps femoris muscle in Microchiropteran species was composed mainly of dense regular connective tissue. The quadriceps tendon in Megachiropteran species with a patella contained an abundance of fibrocartilage and hyaline cartilage, unlike the quadriceps femoris tendon of the Microchiroptera or a laboratory mouse examined for comparison.Conclusions: Four species of the megachiropteran genus Pteropus lacking a bony patella displayed a similar occurrence and distribution of fibro cartilage and hyaline cartilage within the quadriceps tendon as seen in the other bats. In reference to this singular feature, Pteropus is unique among the representatives of megachiropteran and microchiropteran genera examined here. © 1995 Wiley‐Liss, Inc.
Spectrum of looping disturbances in stage 34 chicken hearts after retinoic acid treatment
Authors: Bouman Hannie G. A. , Broekhuizen Monique L. A. , Baasten A. Mieke J. , Gittenberger‐De Groot Adriana C. , Wenink Arnold C. G. 
Published: February 2005

AbstractBackground: In a recently developed chick model the teratogen retinoic acid has appeared to induce a spectrum of double outlet right ventricle, which needs further detailed evaluation. It is known that retionic acid is able to induce cardiac malformations. Although the exact mechanism is not known, an interaction with neural crest cell function is thought to exist.Methods: After treatment with 1 μg all‐trans retinoic acid at Hamburger and Hamilton stage 15 and reincubation until stage 34 of development 41 chicken embryos were evaluated macroscopically and microscopically, supported by graphic reconstructions. These retinoic acid treated embryos were compared with a control group (n = 8).Results: The retinoic acid treated embryos could be divided in three groups. Group 1 (23/41) had an intact septum, group 2 (11/41) had an isolated ventricular septal defect (VSD), and group 3 (7/41) had a double outlet right ventricle (DORV). Besides, in the group with an intact septum 11 hearts showed an abnormal course of the subaortic outflow tract. In the group with DORV a straddling tricuspid orifice (7/8) and a double inlet left ventricle (1/8) could be distinguished. Considering the external contour, the hearts in the DORV group all showed a dextroposed arterial pole. Malformed pharyngeal arch arteries were found in all three groups (11/41) and with a great diversity.Conclusions: The present cardiac malformations in the chicken as a result of retinoic acid treatment are part of a continuous spectrum, varying from hearts with an intact ventricular septum and a normal course of the subaortic outflow tract to a double outlet right ventricle with a straddling tricuspid orifice or even a double inlet left ventricle. A remarkable observation in this spectrum concerns the correlation of malformations of the inflow and outflow tracts, which is explained as a cardiac looping disturbance. The disturbance of the looping process seems to lead to malalignment of septal components, although, in the chick, retinoic acid does not in general interfere with the formation of these septal components themselves. © 1995 Wiley‐Liss, Inc.
Calcium‐binding Proteins in Avian Herbst and Grandry sensory corpuscles
Authors: Del Valle M. E. , Ciriaco E. , Bronzetti E. , Albuerne M. , Naves F. J. , Germana G. , Vega J. A. 
Published: February 2005

AbstractBackground: Calcium‐binding proteins (Ca2+‐BP) are involved in the homeostasis of intracellular calcium ions (Ca2+), which play a key role in electrogenesis, and therefore in somatosensory transduction, within sensory corpuscles. This study analyze the distribution of several Ca2+‐BP in avian Herbst and Grandry sensory corpuscles.Methods: Specimens of beak skin and tongue from ducks and pigeons were studied immunohistochemically using antibodies against S100 protein (S100P), calretinin (CR), calbindin D28K (CB), and parvalbumin (PV). Moreover, neurofilament proteins (NFP) and neuron‐specific enolase (NSE) were studied in parallel.Results: In Herbst corpuscles: (1) specific immunoreactivity (IR) for S100P was always observed labelling the inner‐core cells and was also found in the capsule of duck Herbst corpuscles; (2) all the other investigated Ca2+‐BP were found primarily in the inner‐core, without relevant species‐specific differences, but also in the central axon and in the capsule (CB and PV). In Grandry corpuscles, the Grandry cells (1) can be subdivided on the basis of S100P IR; (2) displayed a strong CR IR, moderate PV IR, and weak CB IR; (3) were negative for NFP or NSE. On the other hand, the central axon of both kinds of sensory corpuscles showed NFP and NSE IR, and the intraepidermic Merkel‐like cells were NFP IR.Conclusions: Present results provide evidence for the presence of several Ca2+‐BP in two kinds of rapidly adapting avian sensory corpuscles, and also for the existence of species‐specific differences in the localization of some of them. These findings suggest that Ca2+‐BP may be involved in the maintenance of Ca2+ homeostasis in avian sensory corpuscles, and therefore in mechano‐electric transduction. © 1995 Wiley‐Liss, Inc.
Three‐dimensional structure of the bronchial microcirculation in sheep
Authors: Schraufnagel Dean E. , Pearse David B. , Mitzner Wayne A. , Wagner Elizabeth M. 
Published: February 2005

AbstractBackground: The bronchial circulation affects both pulmonary vascular and airway activity. Fundamental to understanding the role of the bronchial microcirculation in health and disease is understanding its anatomy. This study sought to identify specific structural elements that might contribute to the drop that occurs between the systemic blood pressure of the bronchial artery and the low pressure of the pulmonary bed into which the bronchial circulation flows and to better describe the connections of the bronchial and pulmonary circulations. METHODS: To do this, the lungs of five sheep were cast by injecting a resin through bronchial and pulmonary arteries. After taking samples for light microscopy, the tissue was digested and the casts were viewed with a scanning electron microscope. RESULTS: Casts of extrapulmonary bronchial arteries were structurally similar to other systemic arteries. Tortuous ones spiraled around bronchi and large blood vessels. Intrapulmonary bronchial arteries, about 100–300 μm in diameter, had sharp branching and deep focal constrictions with great rugosity that completely shut off the flow of the resin. These vessels correspond to the Sperrarterien described by von Hayek (and could cause the resistance associated with the pressure drop). Vasa vasorum ran in the walls of intrapulmonary pulmonary arteries for a variable distance before they entered the lumens of the pulmonary arteries. The smallest blood vessel found that was supplied with vasa vasorum was a bronchial artery 42 μm in diameter. Capillary‐like networks with large luminal diameters were found on the pleural surface. CONCLUSIONS: Scanning electron microscopy of microvasular casts provides a fresh description of the bronchial circulation, further delineates the communications of these two circulations, and may structurally account for some pressure drop between the bronchial and pulmonary circulations. © 1995 Wiley‐Liss, Inc.
Maternal pineal gland participates in prepubertal rats' ovarian oocyte development
Authors: Fernandez B. , Diaz E. , Colmenero M. D. , Diaz B. 
Published: February 2005

AbstractBackground: Sexual maturation is a very complex phenomenom that it is mediated by the ontogeny of the hypothalamus‐pituitarygonadal axis during intrauterine life. The maternal pineal gland can affect fetal development because the main pineal hormone, melatonin, crosses the placental barrier. We found that melatonin treatment during gestation in the rat produced delayed sexual maturation of the female offspring. The present work was undertaken to study the maturational stage of oocytes of prepubertal female rats when their mothers were either pinealectomized (PIN‐X) or treated with melatonin (MEL) during pregnancy.Methods: Three groups of female Wistar rats were used: control, PIN‐X, and those treated (250 μg/100 g body weight) with melatonin throughout pregnancy. Ovaries of 25–30‐ and 34‐day‐old female offspring were studied during the prepubertal phase. Morphometric studies of semithin sections (1 μm) of the ovaries were performed. Oocyte, nuclear, and nucleolar volumes were calculated by a computer‐assisted program (M.I.P.) in an image analyzer Kontron. Regularity of the structures was determined by the frequency distributions of circular and regular form factors.Results: Cytometric study of oocyte structure showed a frequency distribution of regular and circular form factors, with a high degree of regularity very close to unit. Cellular and nuclear volumes of follicular oocytes showed a transitory increase at 30 days of age in control rats. In the offspring of MEL‐treated mother rats, a pattern of oocyte development showed significantly lower nuclear and nucleolar volumes at 30 days of age than at the other time points and significantly lower cellular volume at 34 days of age than at 25 days of age. In the offspring of PIN‐X mother rats, no significant differences in oocyte cellular volumes were observed throughout prepubertal development, but we observed a significantly higher nuclear volume at 25 days of age and a significantly lower nucleolar volume at 30 days of age.Conclusions: These findings show that the maternal pineal gland participates in cellular and nuclear volumes of prepubertal oocyte development. Melatonin treatment during pregnancy resulted in a redirected postnatal oocyte development. © 1995 Wiley‐Liss, Inc.
Mode of action of straight chain hydrocarbons on primary chemoreceptors of the blowfly, Phormia regina
Authors: Steinhardt Richard A. , Morita Hiromichi , Hodgson Edward S. 
Published: February 2005

AbstractThe fundamental actions of straight‐chain hydrocarbons on the three known primary chemoreceptor cell types of the blowfly, Phormia regina, were studied in quantitative terms. Lower alcohols and long‐chain amines act in two stages: first a reversible inhibition, and then injury, of the salt, water, and sugar receptors in the labellar sensilla. The primary effects on salt and water receptors resemble hydrocarbon narcosis of nerve. Effects on sugar receptors, when analyzed kinetically, superficially resemble competitive inhibition. Other evidence, however, indicates that a non‐specific effect on sugar receptor sites is more likely. The electrophysiological results from labellar chemoreceptors indicate that the previously reported hydrocarbon behavioral rejection thresholds are best explained by the inhibition of the sugar receptors. This conclusion is strengthened by further electrophysiological and behavioral tests on tarsal chemoreceptors.
The Influence of neurohumoral transmitter substances on protoplasmic streaming in the myxomycete Physarella oblonga
Authors: Hoitink A. W. J. H. , Van Dijk Gě 
Published: February 2005

AbstractThe authors studied the influence of adrenaline‐like substances and acetylcholine on the protoplasmic streaming in Physarella oblonga, investigating the effect on the duration of the rhythmic period. Adrenaline and noradrenaline proved to cause a shortening, whereas acetylcholine appeared to be capable of causing an extension of the period duration.The authors present and discuss critically the possibility that the adrenergic and cholinergic transmitter substances, which influence the visceral (mechano‐) effectors in the higher animal organism often antagonistically, may also affect an elementary “functional” effector system responsible for protoplasmic streaming, and that in so doing they have comparable effects.The results of experiments with eserine, acetylcholine and a mixture of these two substances render it probable that an acetylcholine esterase and acetylcholine occur in the plasmodium.The mean normal value of the period duration was, calculated from 976 measurements and expressed in seconds: 284.183 ± 1.486 (S.E. of the mean). The average duration of the progressive and the regressive phase was found to be almost the same.
Ascorbic acid metabolism and glycolysis in the polymorphonuclear leucocyte of the guinea pig
Authors: Elliott C. George , Smith M. Doreen 
Published: February 2005

AbstractExudate leucocytes lost approximately 30% of their original intracellular ascorbic acid content during two hour incubation in glucose medium. The same loss was observed for cells containing initially both high and low levels of ascorbic acid. High concentrations of ascorbic acid in the incubation medium depressed lactic acid production and increased oxygen uptake by the cells. Iodoacetate and fluoride at low concentrations decreased ascorbic acid loss from cells during incubation; at high concentrations they increased loss. Ascorbic acid uptake from the medium was inhibited by iodoacetate but stimulated by fluoride.
Growth dynamics of an amphibian tissue
Authors: Reddan John R. , Rothstein Howard 
Published: February 2005

AbstractBy the “labeled mitoses” method of Quastler and Sherman and others, the cell cycle of the germinative zone cells of the bullfrog lens epithelium has been characterized. It has been shown that this cycle lasts approximately 83 days with the DNA synthetic phase enduring 100 hours and G2, 11 hours. G1 occupies over 90% of the total time. the duration of mitosis itself has not been precisely determined. the length of the synthetic phase was corroborated by double labeling with c14 and h3‐thymidine.When the temperature is raised by 6°c, from 24° to 30° the cycle is compressed by 40%.When the nongerminative, central cells of bullfrog lens epithelium are activated (stimulated to undergo DNA synthesis and mitosis) by injury or through in vitro culture, the length of the cycle also appears to decrease. in the in vitro experiments the generation time, as judged by the period elapsing between two successive bursts of DNA synthesis involving the same cells, amounts to 177–190 hours at 24°c. by raising the temperature to 30°c the time from injury or isolation until the appearance of the first wave of mitosis is reduced by 20%.
Transport of sugars into human red blood cell ghosts
Authors: Lacko L. 
Published: February 2005

AbstractIt has been found that human red cell ghosts react differently in the presence of various sugars in the medium. The stability of spheric ghosts is preserved in solutions of sugars entering red cells by means of the common carrier. In media of other sugars the ghosts' shapes change to shrunken, crenated forms and between the microscope slides to discoid ones. Under the conditions employed it was further observed that the incubation of fructose‐ or rhamnose‐containing ghosts in solutions of sugars sharing the carriers led to an equilibration of sugars between the medium and the ghosts. The impermeability of ghosts for sugars not sharing the carriers was supported by the finding that fructose could be washed out to a much less extent than glucose. These results suggest that sugars without affinity to the carriers may move in the erythrocyte membrane through nonspecific sites (pores, channels).
Hemoglobin functions in the blood of Bufo marinus
Authors: Hall F. G. 
Published: February 2005

AbstractThe effects of three physical‐chemical factors, temperature, hydrogen ion concentration, and partial pressure of oxygen, on the respiratory functions of blood of the toad (Bufo marinus) have been studied.Measurements of oxygen affinity of hemoglobin in whole blood were measured tonometrically by a method devised for small quantities of blood. At pH 7.40 and 25°C blood was found to be 50% saturated with oxygen at a partial pressure of 44 mm Hg of oxygen. The Bohr effect was measured at various temperatures and found to be about one‐half that found for mammalian blood. Carbon dioxide content of toad blood changes only slightly in the oxygenated and reduced states. Thus the “Haldane” effect parallels the small Bohr effect. Toad blood was found to have average hematocrit values of 37% for erythrocytes and average hemoglobin values of 11 gm/100 ml per cubic millimeter of blood. The respiratory functions of the blood of the toad conform to the pattern of respiratory mechanisms available for gas exchange between the environment and tissues of the organism.
Contraction of protoplasm. II. Theory: Anodal vs. Cathodal in relation to calcium
Authors: Jahn Theodore L. 
Published: February 2005

AbstractIt has been known for over 100 years that when the protoplasm of protozoan cells respond to electrical stimulation by contraction, contraction always starts at the anodal end (e.g., Spirostomum, Jones, Jahn and Fonseca, 1965). It also is known that the cell membrane of protozoa does not have a self‐propagating depolarizing action potential of the type found in axons and muscle cells.If we assume that contraction of the cytoplasmic protein is caused by an increased association of calcium with the protein, as known for muscle, these antithetical facts can easily be explained. Another necessary assumption is that all of the anionic sites on the protein have associated counterions, in accordance with the theories of Debye‐Hückel, Ling, and Eisenman.On the basis of known ionic electrical mobilities it can be predicted for cells with non‐excitable membranes that calcium (1) is removed from both the inside and the outside of the membrane at the cathodal end and is added to both sides at the anodal end, (2) is added to cytoplasmic protein throughout the cell, but is added more rapidly at the anodal end, and (3) is made available for addition to cytoplasmic protein at the cathodal end, as it is released from the membrane. In a cell with an excitable membrane the above will be true, and furthermore (4) the action current will release larger quantities of calcium than those resulting directly from the stimulus. For these reasons it is predictable that in cells with a non‐excitable membrane, contraction should start at the anodal end, whereas in cells with excitable membranes, it should start at the cathodal end, and that is exactly what occurs.
Malignant transformation in Vitro of chinese hamster embryonic fibroblasts with the Schmidt‐Ruppin strain of Rous sarcoma virus and karyological analysis of this process
Authors: Hložánek Ivo , Donner Ludvík , Svoboda Jan 
Published: February 2005

AbstractUsing a method of cocultivation of embryonic Chinese hamster cells (CHEF) with Rous sarcoma cells and infection of CHEF by RSV‐SR, it was possible to obtain malignant transformation of hamster cells. The morphologically altered cells became apparent within 15–36 days.In the cells transformed by cocultivation, the genome of RSV was determined by the method of contact of the transformed cell and the chicken cell in vivo; the malignant character of the transformed cells was demonstrated by transfer to a homologous newborn host. Repeated attempts to detect virus production in transformed Chinese hamster cells failed.Prior to malignant transformation and in early transformed cultures the diploid stem‐line was maintained. A slight decrease in the proportion of diploid cells in transformed cultures was revealed in some experiments and is discussed. Prolonged cultivation of these cells, as also of control fibroblasts, shifts the stem‐line to the hyperdiploid or hypotetraploid region.The mechanism of malignant transformation by RSV is discussed with regard to the action of the viral genome and alteration of the genetic make‐up of the cell by the virus.
Phosphate transport in fertilized sea urchin eggs. I. Kinetic aspects
Authors: Chambers Edward L. , Whiteley Arthur H. 
Published: February 2005

AbstractProperties of the fully developed phosphate transport system in the fertilized egg of the sea urchin, Strongylocentrotus purpuratus, were investigated. The rates of phosphate transport at concentrations of external phosphate of 1 to 44 μM, both in the absence and in the presence of 100 μM arsenate, exhibit typical saturation kinetics. At sea water concentrations of 2 μM phosphate, the rate of uptake is about 2 × 10−9 μm/egg/minute at 15°C. Arsenate is a competitive inhibitor of phosphate transport, fully and immediately reversible in its effects, yielding Ki values ranging from 10.5 to 14.1 × 10−6 M in comparison to the corresponding apparent KM (Michaelis‐Menten) constants for phosphate of 5.6 to 7.5 × 10−6 M (pH 8.0, 15°C).The rate of arsenate uptake in a phosphate deficient medium amounts to 2.8 to 2.9 × 10−10 μm arsenate/egg/minute at an arsenate concentration of 2.9 to 10.2 μM arsenate (HAsO4−−), which is 9.5 and 5.6% of the rate of phosphate uptake at corresponding phosphate concentrations.Arsenate has essentially the same developmental effects at initial concentrations of 5–10 μM and 100 μM arsenate, namely no observable effects for exposure periods of 7.5 hours, although longer periods result in blockage of development at the early blastula stage.Outward flux of phosphate ions cannot be demonstrated by washing prelabelled eggs with sea water containing low or high concentrations of phosphate, even when phosphorylation has been blocked by exposing the eggs to a metabolic inhibitor.Phosphate uptake rates measured in the pH range from 5.0 to 10.0 reveal a sharp optimum at pH 8.8–8.9. Reference to the apparent pK' values of the phosphoric acid system indicate that the entering species is the HPO4−− ion. The effects on rates of phosphate uptake of exposure to sea water at pH values between 7 and 10 for 30 minute periods are fully reversible, but at lower pH values, reversal is delayed, and is only partial.Sodium molybdate (0.01 M), sodium pyrophosphate (1.5 × 10−4 M), and adenosine triphosphate (1–5 × 10−4 M) for exposure periods ranging from 40 to 180 minutes did not significantly affect phosphate uptake. Omission of Ca++ ion from artificial sea water is without effect on phosphate uptake but the absence of both Ca++ and Mg++ results in profound and irreversible depression of both phosphate uptake and development.The data of this and the following paper are consistent with the conclusion that the transport of phosphate involves a surface located carrier.The apparent secondary and tertiary ionization constants of phosphoric acid in sea water (ionic strength = 0.6885) were measured, resulting in a value for pK′2 = 6.14 and for pK′3 = 10.99, at 15°C and phosphate at infinite dilution.