bluuebunny/crossref_metadata_2025_split huggingface dataset:
Complex structure of the common carotid artery of sheep
Authors: Gabella Giorgio 
Published: February 2005

AbstractBackground: Mechanical properties of blood vessels are dictated by the vessel wall structure. In many large conduit vessels the tunica media is a sheath of circular musculature and the tunica adventitia a layer of fibrous connective tissue with limited longitudinal extensibility. In contrast, the carotid artery of the sheep displays in each tunica a more complex architecture of muscle and connective tissue.Methods: Vessels collected from ewes were measured and processed for light microscopy and for transmission electron microscopy.Results: Layers of histologically different materials are found within the tunica intima, media and adventitia. (1) The tunica media is made of circumferentially arranged muscle cells markedly different at different depths. In the innermost third of the media. muscle cells are small and with irregular profiles, the cells are widely separated, and the extracellular material is abundant and composed mainly of elastic fibres. In the outermost third, muscle cells are larger and with more regular profiles, the cells are relatively close to each other and the extracellular material is sparse and consists mainly of collagen fibrils. (2) A small number of fibroblasts is found in all parts of the media amongst the preponderant muscle cells. (3) The intima contains fibroblast‐like cells and longitudinally arranged muscle cells. (4) The adventitia contains a thick layer of collagen and elastic fibres; external to this, it displays a conspicuous musculature, made of large bundles of longitudinal muscle.Conclusions: The carotid artery of the sheep presents in all three coats of its wall features which are at variance from those in the better known vessels of small laboratory animals. The presence of many layers of material within the wall, the heterogeneity of the tissues found, and the occurrence of an extensive longitudinal musculature, have important effects on the mechanical properties of the vessel. © 1995 Wiley‐Liss, Inc.
Studies on the fetal development of the gubernaculum in cetacea
Authors: van der Schoot P. 
Published: February 2005

AbstractBackground. Adult cetacean males, like non‐mammalian vertebrates and other testicond mammals, have intra‐abdominal testes. There is no evidence of a processus vaginalis in them. Testicondia in cetaceans is considered secondary as they are judged, evolutionarily, the descendants of terrestrial mammals (ungulates) with testis descent. A possible argument in support of the latter contention would be that cetacean fetuses develop gubernacula which are the primordia of the processus vaginalis and other structures associated with testis descent in other placental mammals. the present study intended to analyse cetacean fetuses in this respect.Methods. Serial sections of 25 fetuses (total body length between 39.5 and 160 mm) of 4 cetacean species (Delphinus delphis, Phocoena phocoena, Eschrichtius robustus, Physeter catodon) were examined with special attention to the presence or absence of structures homologous to the gubernaculum of other placental mammals (rats and humans).Results. Gubernacular primordia were observed in fetuses from about the time of onset of sexual differentiation. Their shape and anatomical relationship with the surrounding structures were similar as those in mammals with testis descent. The gubernaculum in males developed into a large mass of dense connective tissue in the ventral‐caudal abdominal region at the site of the insertion of the mesonephric inguinal ligament and associated to the tip of the internal abdominal oblique muscle. No (or only very little) development of a processus vaginalis was noticed.Conclusions. The results demonstrate initial emergence of mammalianlike gubernacular primordia in cetacean fetuses without their further development to elaborate structures required for testis descent. The findings support the view that cetaceans are secondarily testicond. It is suggested that (1) absence of the pelvic girdle together with (2) the development of structures in and beyond the caudal abdominal region, particularly the caudal hypaxial musculature, precludes the outgrowth, into caudal direction, of hollow organs (such as the processus vaginalis) from the abdominal cavity. © 1995 Wiley‐Liss, Inc.
Combined vascular‐bronchoalveolar casting using formalin‐fixed canine lungs and a low viscosity silicone rubber
Authors: Nettum John A. 
Published: February 2005

AbstractBackground: Previous work using unfixed or fixed tissues has shown that casts can be made that demonstrate the three‐dimensional structure of tissues such as the bronchoalveolar tree or the vasculature. In this report, a new method for creating a vascular‐bronchoalveolar cast is described.Method: Canine lungs were taken from storage in formalin. Silastic 734 RTV (room temperature vulcanizing) with added red or blue pigments was injected into the pulmonary arteries and veins, respectively, using compressed air. This was followed by filling the airway with clear (translucent) Silastic 734 RTV. The lung tissue was then corroded with potassium hydroxide.Results: Vascular‐bronchoalveolar casts were recovered giving fine detail as shown using stereo light microscopy or scanning electron microscopy.Conclusions: This method may be useful for not only microvascular anatomy studies of lungs, but also for studying the microvasculature of other normal and diseased tissues. © 1995 Wiley‐Liss, Inc.
Electrochemical probe for on‐chip type flow immunoassay: Immunoglobulin G labeled with ferrocenecarboaldehyde
Authors: Okochi Mina , Ohta Hiroko , Tanaka Tsuyoshi , Matsunaga Tadashi 
Published: February 2005

AbstractLabeling of ferrocenecarboaldehyde (Fc‐CHO) to immunoglobulin G (IgG) via formation of Schiff‐base and its reduction was investigated for construction of an electrochemical probe for miniaturized amperometric flow immunoassay. Approximately eight molecules of Fc‐CHO were labeled to IgG and the reversible redox property of ferrocene was observed. Labeling efficiency improved by over three times as compared to the conventional method using ferrocenemonocarboxylic acid (Fc‐COOH). Also, binding affinity of IgG labeled with Fc‐CHO to its antigen, IgE, was investigated by enzyme‐linked immunosorbent assay (ELISA) and surface plasmon resonance assay. IgG labeled with Fc‐CHO that retained eight ferrocene moiety showed sufficient binding affinity to its antigen and the current response obtained in the flow electrochemical detection system increased by 14‐fold as compared with IgG labeled with Fc‐COOH when applying the potential of 390 mV vs. Ag/AgCl. The minimum detectable concentration of IgG labeled with Fc‐CHO was 0.06 μM. IgG labeled with Fc‐CHO demonstrate biochemical and electrochemical properties that are useful for electrochemical immunosensors. © 2005 Wiley Periodicals, Inc.
Studies on synchronously dividing cultures of Euglena gracilis Klebs (strain Z). III. Circadian Components Of Cell Division
Authors: Edmunds Leland N. 
Published: February 2005

AbstractEuglena gracilis Klebs (Z) was grown axenically and autotrophically in four‐liter serum bottles at 25°C on an aerated, continuously stirred, inorganic salt medium. Four fluorescent illumination regimes were employed: (1) continuous bright light of 3500 lux (LLb); (2) continuous dim light of 800 lux (LLd); (3) a LbD: 14, 10 (3500 lux) light‐dark cycle; and (4) a LdD: 14, 10 (800 lux) light‐dark cycle. Cell number was automatically monitored throughout all experiments.In LLb the generation time (G.T.) of the population was about 12 hours, whereas in LLd following LLb it was approximately five days; exponential growth occurred in either case. In LbD: 14, 10 synchronous growth occurred with a doubling of cell number every cycle of 24 hours. In LdD: 14, 10, however, although rhythmic cell division took place every 24 hours, the average increase in cell number during the division burst which occurred in each dark period was only 13.4%, so that the G.T. of the culture was about five days, as was the case for LLd. In the constant conditions of temperature and continuous dim light (LLd), following synchronous growth in LbD: 14, 10, small (17.0%) rhythmic division bursts lasting 14.5 hours continued to occur for at least ten days, with a period of 24.2 hours. The overall G.T. of the culture was about five days. These data demonstrating the circadian, endogenous nature of rhythmic cell division under certain conditions of continuous dim illumination were discussed in relation to the synchronous division observed in temperature and light‐dark cycles.
Acid‐base, fluid and electrolyte metabolism in the elasmobranch. III. oxygen, CO2, bicarbonate and lactate exchange across the gill
Authors: Robin Eugene D. , Murdaugh Herschel V. , Millen J. Eugene 
Published: February 2005

AbstractMethods have been developed which permit measurements of cardiac output and sampling of mixed venous and arterial blood in the elasmobrach, Squalus acanthias. These methods have been utilized to characterize some of the parameters involved in gill gas exchange. A total of 17 animals have been studied with the following results. Cardiac output: 1.49±0.57 1/kg/hr.; V̇o2: 38.3±22.1 ml/kg/hr.; V̇co2: 32.1±19.0 ml/kg/hr.; RER: 0.92±0.17; PaO2: 104±27 mmHg; Pv̄o2: 18±8.8 mmHg; PaCO2: 2.9±0.75 mmHg; Pv̄co2: 4.6±1.1 mmHg; CaO2: 3.8±0.75 vol. %; Cv̄o2: 1.26±0.59 vol. %; pHa: 7.52±0.10 units; Pv̄: 7.42±0.11 units; [HCO3−]a: 3.92± 1.14 meq/1; [HCO3−]v̄: 4.80±1.15 meq/1; [dissolved CO2]a: 0.17± 0.04 mM/1; [dissolved CO2]v̄: 0.24±0.04 mM/1; [lactate−]a: 13.47±7.17 meq/1; [Lactate−]v̄: 13.01±8.18 meq/1. Some of the mechanisms involved in gill gas exchange have been characterized.
Respiration and glycolysis in the human diploid cell strain wi‐38
Authors: Cristofalo V. J. , Kritchevsky David 
Published: February 2005

AbstractAssessment of the respiratory and glycolytic capacity of non‐growing WI‐38 cells shows that, in the absence and presence of added glucose, the mean rates of oxygen consumption were 247 (QO2 = 5.61) and 208 (QO2 = 4.73) mμmoles/mg dry wt/hr., respectively. Mean glucose consumption was 225 mμmoles/mg dry wt/ hr. With uniformly labeled 14C glucose as substrate, 36 mμg atoms of carbon dioxide were produced, corresponding to 15–20% of the total cellular respiration. Mean values for lactate production in the presence and absence of glucose were 345 (QLO2 = 7.85) and 196 (QLO2 = 4.45) mμmoles/mg dry wt/hr., respectively.Human diploid cells in culture age, in the sense that their ability to proliferate decreases with time during serial subcultivation. Studies of their respiratory and glycolytic capacity as a function of the aging process showed that total respiration, glucose respiration and glycolytic capacity were relatively constant for cells in the middle and late passages and indicate that aging in this sense is not directly related to the respiratory and glycolytic capacity of the cell.
Hemolysis of elasmobranch erythrocytes in urea solutions: Effect Of Temperature
Authors: Rabinowitz Lawrence 
Published: February 2005

AbstractSkate and stingray cells were shown to hemolyze in isosmotic solutions containing urea as the sole solute. The rate of urea penetration into these cells as determined by the rate of hemolysis is highly temperature dependent with a Q10 of 2.50–2.75. A reduced rate of methylurea penetration in the presence of urea was reconfirmed. The present results are consonant with the hypothesis of carrier mediated transport of urea in elasmobranch erythrocytes previously proposed by Murdaugh, Robin and Hearn.
The influence of temperature on the water exchange in amphibian eggs and embryos
Authors: Haglund Birgit , Løvtrup Søren 
Published: February 2005

AbstractThe water exchange has been measured in oocytes of siredon mexicanum and rana temporaria, and in unfertilized eggs and early gastrulae of the former species, by recording the D2OH2O exchange with the cartesian diver balance.In oocytes, where no diffusion barrier to water is demonstrable, the temperature coefficient Q10 for the exchange of water is about 1.3–1.4, corresponding to that of free diffusion. in unfertilized eggs, and in early gastrulae the exchange is considerably slowed down, indicating that a surface membrane to some extent limits the rate of exchange. at the same time the Q10 value is increased, lying in the range 2.3–3.8. since it is most likely that the exchange even in this case occurs by diffusion, but through membrane pores, it is concluded that the area available for diffusion (pore size or number, or both) increases with temperature.
Reversed potentials in isolated frog skin. II. Active transport of chloride
Authors: Martin Duncan W. , Curran Peter F. 
Published: February 2005

AbstractNet inward transport of Cl in the absence of an electrochemical potential difference was demonstrated in the skin of two species of frog, R. pipiens and R. esculenta under conditions of low (2 mM) Cl concentration in the bathing solutions. The electrical potential profile of skins of R. pipiens was examined with microelectrodes under conditions in which the inside solution was negative relative to the outside solution. This reversal of the normal potential difference was found to arise as a result of potential changes across the outward facing electrical barriers in the skin. The reversed potential difference appears to arise, at least in part, as a result of the inward Cl transport. The effect may be due either to electrogenic Cl transfer or to variations in internal composition of the epithelial cells arising as a result of Cl transport.
The hibernation cycle and related changes in the brown fat tissue of Citellus lateralis
Authors: Grodums E. I. , Spencer W. A. , Dempster G. 
Published: February 2005

AbstractThe hibernating habits of Citellus lateralis under standard laboratory conditions are described. It has been shown that it is possible to use a biopsy technique to investigate the brown fat tissues without serious disturbance to the hibernation pattern. This technique was used to sample brown and white fat tissues in the same animal at various seasons of the year. Histological studies did not reveal any changes in morphology or lipid composition which could be related purely to the hibernating season, however, during the short periods of arousal a large proportion of the brown fat cells appeared to be partially depleted of neutral fat. At this time a large increase in Luxol fast blue staining was always observed, which may be due to unmasking of tissue phosphatides.
Experimental coxsackie B‐3 virus infection in Citellus lateralis
Authors: Dempster G. , Grodums E. I. , Spencer W. A. 
Published: February 2005

AbstractCoxsackie B‐3 virus produces a mild infection which passes unnoticed in the non‐hibernating Citellus lateralis. A severe infection occurs in the hibernating animal. The progress of infection in the hiberating animal is related to the number of arousal hours and quite independent of the number of infected days. Nevertheless, it has been shown that the low‐temperature hibernation phase has a potentiating effect upon subsequent viral production. Infective virus has not been found in the inoculated brown fat pads during the hibernation phase but very high virus titers are recorded 48 hours after arousal. This results in an earlier viraemia and earlier and higher titers in other organs of the body. A similar effect is noted when virus is inoculated at the very beginning of the arousal phase. While most animals recover with subsequent antibody development, a few succumb. Antibody development is slow and related only to the number of arousal hours experienced.Particular note is made of the fact that an animal may successfully resume hibernation despite complete loss of the axillary brown fat pads.
Response of cultured chick heart cells to changes in ionic environment
Authors: Levinson Charles , Green James W. 
Published: February 2005

AbstractVentricles from 11‐day‐old chick embryonic heart were disaggregated by elastase and the component cells cultured on glass in maintenance medium containing 10 μc of P32. After 48 hours incubation at 37°C the medium was removed, the cells rinsed and exposed to a phosphate‐free test solution for two hours. During this period samples of the test medium were removed for counting and spectrophotometric analysis. Cells incubated in solutions lacking amino acids or vitamins or serum components lost phosphate at essentially the same rate as in the complete culture medium; furthermore such cells lost very small amounts of nucleotide materials. Cells incubated in 0.16 M NaCl lost phosphate and nucleotides rapidly; the addition of either K+ or Ca+2 or Mg+2 reduced phosphate and nucleotide loss and cells in balanced saline media containing all four cations, retained phosphate and nucleotides at essentially the same level as in the complete medium. These results show that primary isolated chick heart cells can be maintained for short periods in physiological saline solutions without injury and that saline balance in short term studies is a primary factor in maintaining these cells in an uninjured state.
Effect of thermal conductance on water economy in the antelope jack rabbit, Lepus alleni
Authors: Dawson Terence , Schmidt‐Nielsen Knut 
Published: February 2005

AbstractThe heat and water balance of the antelope jack rabbit, Lepus alleni, was studied at various ambient temperatures. At high ambient temperature the animal primarily depends on evaporation for dissipation of the heat load. The use of water was, however, less than could be expected if only body size is considered.It was shown that, when the ambient temperature is below body temperature, there is a two‐ to three‐fold increase in the conductance of the animal as ambient approaches body temperature. This facilitates dry heat loss and contributes to water economy. At ambient temperatures above body temperature the direction of heat flow is reversed, now being from the environment to the body. In this situation the heat flow inwards is impeded by a decrease in conductance to minimal values, thus achieving a considerable saving in the use of water for evaporation.
Differential effects of strychnine on crustacean slow, fast, and inhibitory neuromuscular systems
Authors: Parnas I. , Atwood H. L. 
Published: February 2005

AbstractThe effect of strychnine was studied on the slow, fast, and inhibitory systems in the abdominal extensor muscles of the crayfish. Strychnine nitrate (0.1 mg/ml and up) caused rapid block of the fast responses of the deep abdominal extensor muscles. The nerve and muscle remained directly excitable, and the blocked preparation contracted with added glutamate. It is concluded that strychnine acts mainly presynaptically or to neutralize the transmitter substance. No marked effect was observed on the purely slow superficial extensor muscles or on inhibitory systems. Essentially the same results were obtained in other slow and fast systems of Pachygrapsus and Panulirus. The possibility of a common transmitter substance for the slow and fast neuromuscular systems is discussed.
Contraction of protoplasm. I. Cinematographic analysis of the anodally stimulated contraction of spirostomum ambiguum
Authors: Jones Alick R. , Jahn Theodore L. , Fonseca James R. 
Published: February 2005

AbstractElectrically stimulated contraction of Spirostomum ambiguum was investigated by high speed cinematography (up to 6,000 pps). Contraction is completed in about 4 msec following a latent period of up to 30 msec. Reduction in length during contraction followed a sigmoid curve, and final length was about 50% of the original length. Contraction always started at the end of the animal directed towards the anode. When the length of each half was measured separately, it was found that the cathodal end lagged about 1 msec in all cases observed. Rate of contraction was increased when the external calcium contraction was increased, and was decreased in Ca‐free and K‐free solutions, but was unchanged in K‐rich solutions. These results are interpreted in terms of contraction being associated with a relative increase of calcium bound to the contractile protein. The differential migration of potassium and calcium ions in an electric current would result in a temporary lowering of K+ at the anodal end of the animal, hence a relative rise would take place in the Ca++ available for binding. The results of experiments using changed calcium and potassium concentrations can be explained by this hypothesis which is in general agreement with modern work on muscle contraction and relaxation.
Influence of ions and tonicity of RNA metabolism in Tetrahymena pyriformis
Authors: Cline Sylvia G. 
Published: February 2005

AbstractNet RNA degradation occurs in Tetrahymem pyrifmmis when this ciliate is suspended in a non‐nutrient medium. The quantity and quality of the excretion products is at least partially under the control of the ionic content and the tonicity of the cellular environment. The excretion of ultraviolet‐absorbing materials was found to be elevated by sodium ions in a medium isotonic to the culture fluid, or by a hypertonic environment. Magnesium counteracted these effects.In isotonic suspension, sodium and magnesium ions lowered orthophosphate excretion; however, sodium altered the nature of the phosphate products so that acidlabile phosphates were also excreted rather than solely orthophosphate. Similar results were obtained in a hypertonic environment with or without sodium.The degree of purine and pyrimidine loss from the cells in all conditions of suspension was reflected in the amount of RNA degraded. The ion and tonicity effects apparently reflect events which alter the stability of the RNA and the properties of the membrane system, resulting in changes in both the rate of RNA degradation and the nature of the excreted products. The rates of orthophosphate excretion appear to be affected by changes in the acid‐base balance within the cell which may be governed by the cation levels. The manipulation of the ionic content and tonicity of the medium offers a convenient method for obtaining cells reduced in RNA content.
Delayed inhibition of DNA synthesis in mouse jejunum by low doses of Actinomycin D
Authors: Baserga Renato , Estensen Richard D. , Petersen Robert O. 
Published: February 2005

AbstractActinomycin D (0.008 μg/gm of body weight) injected intraperitoneally every two hours, produced a prompt 50% inhibition of RNA synthesis in the jejunum of mice, and a delayed inhibition of DNA synthesis, that reached its maximum inhibition (68% of control values) 4.5 hours after the first injection of actinomycin D. Autoradiographic studies indicated that this low level of actinomycin D inhibited a step in the G1 phase of the cell cycle, preventing the initiation, but not affecting the continuation, of DNA biosynthesis. The activity of DNA polymerase was not affected under these conditions. The results are substantially similar to those previously obtained with Ehrlich ascites cells growing in the peritoneal cavity of mice and can be interpreted as indicating that in the G1 phase of dividing cells there is an actinomycin sensitive step whose inhibition prevents the entrance of cells into the DNA‐synthesis phase.
Extraction of an actin‐like protein from the plasmodium of a myxomycete and its interaction with myosin a from rabbit striated muscle
Authors: Hatano Sadashi , Oosawa Fumio 
Published: February 2005

AbstractAn actin‐like protein was obtained from the plasmodia of a myxomycete, Physarum polycephalum. It forms a complex with muscle myosin A which behaves similarly to the actomyosin from rabbit striated muscle. On the addition of ATP the complex of this protein with myosin A shows a viscosity drop at high concentrations of KCl (∼0.5 M). At low concentrations of KCl (∼0.05 M) this complex superprecipitates from solutions containing 1 mM MgCl2 and shows Mg‐activated ATPase activity. That is, the actin‐like protein converts the ATPase of myosin A to the actomyosin type.