The effect of shock on blood oxidation-reduction potential.

Oxidation-reduction (redox) potential measurements were made in the blood of rabbits subjected to hemorrhagic shock followed by treatment with a mild oxidizing agent (albumin). Control redox potential reading corrected for pH was -8.8 +/- 1.3 millivolts (mV) in arterial blood (A) and -18.0 +/- 2.0 mV in venous blood (V). This A-V difference indicated that hydrogen equivalents coming from muscle and other tissues were partially consumed in the lungs. A 20-mV drop on the V and a 13 mV on the A side was seen after shock. This did not fully return to control 2 h after return of the shed blood. Infusion of 2 g of albumin/kg/h raised the V redox potential to control, but it returned to untreated levels when the albumin was discontinued. The reductive load imposed on the animal by shock appeared to be large and not readily reversed by reperfusion or by the quantity of albumin given. Thus, it may be concluded that cellular respiration had not been adequately restored. This reductive load may impede recovery by suppression of cellular respiration and other cell and organ functions.     

HCN channels contribute to the intrinsic activity of cochlear pyramidal cells

A hyperpolarization-activated current recorded from the pyramidal cells of the dorsal cochlear nucleus was investigated in the present study by using 150- to 200-m-thick brain slices prepared from 6- to 14-day-old Wistar rats. The pyramidal neurones exhibited a slowly activating inward current on hyperpolarization. The reversal potential of this component was –32 ± 3 mV (mean ± SE, n = 6), while its half-activation voltage was –99 ± 1 mV with a slope factor of 10.9 ± 0.4 mV (n = 27). This current was highly sensitive to the extracellular application of both 1 mM Cs⁺ and 10 M ZD7288. The electrophysiological properties and the pharmacological sensitivity of this current indicated that it corresponded to a hyperpolarization-activated non-specific cationic current (I_h). Our experiments showed that there was a correlation between the availability of the h-current and the spontaneous activity of the pyramidal cells, suggesting that this conductance acts as a pacemaker current in these neurones. Immunocytochemical experiments were also conducted on freshly isolated pyramidal cells to demonstrate the possible subunit composition of the channels responsible for the genesis of the pyramidal h-current. These investigations indicated the presence of HCN1, HCN2 and HCN4 subunits in the pyramidal cells.Received 15 May 2003; received after revision 26 June 2003; accepted 21 July 2003     

Hemodynamic studies in a parabiotic model of portal hypertension

Summary Splanchnic and systemic hemodynamic studies were performed in a rat model of parabiosis and portal hypertension. A portal hypertensive and a normal rat were surgically united side to side. A hyperdynamic circulation, characterized by increased cardiac index (413±26 vs 318±23 ml·min^–1·kg^–1; p<0.05) and portal venous inflow (9.61±1.29 vs 6.33±0.36 ml·min^–1·100 g b.wt^–1; p<0.05), was found in all the portal hypertensive rats but not in the normal parabiotic partners. These results do not support the existence of a transferable humoral factor mediating the hyperdynamic circulatory state of chronic portal hypertension.Acknowledgment. The authors express their appreciation to Martha Shea for technical assistance.     

On the production of 12α-hydroxysteroid dehydrogenase fromClostridium group P,strain C48-50 ATCC 29733

Summary The production of 12-hydroxysteroid dehydrogenase ofClostridium group P strain C48-50 was optimized when the organism was grown in the presence of 2% fructose and 0.1% dithiothreitol. It appears that an initial redox potential of less than –160 mV (achieved by autoclaving in the presence of dithiothreitol, dithioerythritol or cysteine) is important in the production of this enzyme.     

Über die Molekulargrösse des Hämovanadins

Summary The red-brown haemovanadin which is contained in the haemolysate (Henze Solution) of blood cells of the ascidiaPhallusia mamillata Cuvier is a chromoproteid with trivalent vanadium as the central atom and sulphuric acid bound coordinatively. It is found to have a molecular weight of 24,400±1,900 according to the estimation of the diffusion coefficient (D_5°=6.87±0.2 · 10^–7 cm² · s^–1 at pH 2.5–2.8).

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Dem Entdecker des Hämovanadins zum 80. Geburtstag gewidmet.     

The pharmacokinetics of VIP in dog and pig

Summary Pure porcine VIP was infused systemically in 4 conscious dogs and systemically and intraportally in 6 anesthetized pigs. At 2.3 pmoles·kg^–1·min^–1 the MCR was 10.7±1.0 ml·kg^–1·min^–1 in dog and 7.6±1.5 (systemic) and 16.5±2.0 (portal) in pig. The t 1/2's were 1.0±0.12 and 1.0±0.05 respectively. These values agree with those observed in man. This very high single pass tissue clearance does not suggest a hormonal role for VIP.     

Elektrische Eigenschaften von Glasmikroelektroden nach Membranpotentialmessungen an Zellkulturen

Summary On KB cancer cells in the cover-glass culture with glass micro-electrodes we measured a middle membrane-potential of minus 11–13 mV. It is possible that the electrical qualities of the glass micro-electrodes may alter after some hundred makings of cell-points. An enlargement of the potential on the peak of the electrode (tip-potential) to — 30 mV has no influence on the result of the measuring.     

Cartsian diver studies on respiration of rat bone marrow cells in the presence of erythropoietin and anti-erythropoientin

Résumé L'étude de la respiration des cellules de la moelle des os du rat fut faite avec un plongeur Cartésien. Ces cellules, avec ou sans glucose, repirent à raison de 0,73±0,15 et 0,97±0,17×10^–6 l O₂/cellule/h. Comparée aux mesures de contrôle, la respiration des cellules médullaires de rats pléthoriques est plus fabile en présence de ESF (0,45 contre 0,99×10^–6 l, O₂/cellule/h). Cette inhibition fut supprimée par la présence d'anti-ESF (0,98 contre 0,99×10^–6 l O₂/cellule/h).

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This research was supported by funds from a Damon Runyon Cancer Research Training Grant and the US Public Helath Seervice. The senior author was a Damon Runyon Post-Doctoral Traince.     

Tip potentials in microelectrodes filled by boiling under reduced pressure

Zusammenfassung Glasmikroelektroden, mit 3M KCl-Lösung gefüllt durch Kochen in Wasserstrahlvakuum, zeigen einen Zentralwert für das Potential an der Elektrodenspitze (tip-potential) von –2,5 mV; 75% geben entsprechende Werte niedriger als –5 mV. Lagerung der Elektroden bei 6°C lässt das «tip-potential» mindestens 2 Wochen unverändert, während bei 22 °C sein Zentralwert nach 3–4 Tagen grösser als –5 mV wird.     

Über den Einfluss von Acetylcholin auf das Membranpotential denervierter Rattenzwerchfelle

Summary The membran potential of isolated rat-diaphragms has been measured by means of intracellular micro-electrodes, in order to study changes of the resting potential and of the depolarizing action of acetylcholine after section of the phrenic nerve. Within 80 days after denervation, the membrane potential was found to fall exponentially from 87 mV to 66 mV. The action of acetylcholine, on the other hand, was found to be independent of the duration of denervation: between the 4th and the 80th day of denervation: 10^–5g/ml acetylcholine always caused the membrane potential to fall by an average of the 9 mV.     

Calcium ionophore plus excision induce a large conductance chloride channel in membrane patches of human colon carcinoma cells HT-29cl.19A

In excised inside-out membrane patches of the human colon carcinoma HT-29cl.19A cells a large conductance (373±10 pS) chloride channel was found. Channel activity could only be observed after excision of patches from cells incubated with calcium ionophore. The channel was never observed in cell-attached patches. The channel was strongly voltage dependent, being open only between +30 and –30 mV clamp potentials. The selectivity sequence among anions, deduced from reversal potentials, was I>Br>Cl>F>gluconate. The P_Na/P_Cl was 0.09. Although a similar type of channel, has been described earlier, this is the first report stating its appearance in patches of intestinal epithelial cells requiring the combined action of Ca²⁺ ionophore and excision, suggesting its control by an intracellular compound.     

Wellenlängen-Diskriminatoren im intrakranialen Pinealorgan vonRana catesbyana

Summary The photosensitivity of the epiphysis cerebri of bullfrogs (Rana catesbyana) was investigated by recording with 3 M-KC1 glasscapillary microelectrodes. Of 65 units isolated from the tractus pinealis 21 were inhibited by short wave lengths and excited by longer wave lengths (chromatic response), 44 units were inhibited by all wave lengths (achromatic responses). Most effective for the excitatory component of the chromatic response was green. The spike amplitude of the chromatic response was 5–15 mV, that of the achromatic response 30–40 mV.     

The effect of chronic heat stress on cortisol levels in the antarctic fishPagothenia borchgrevinki

Radioimmunoassay was used to determine levels of the stress-inducible glucocorticoid, cortisol, circulating in the plasma of the extremely stenothermal Antarctic fishPagothenia borchgrevinki at rest and after heat stress. Fish sampled immediately after capture (–1.9°C) had low cortisol levels (10.4±1.4 ng ml^–1, mean±SEM) as did fish which were laboratory rested for 3 days. Sudden exposure to 5°C (48h) resulted in a peak cortisol value after 3 h (69.9±6.8 ng ml^–1) whereas exposure to 8°C (6h) resulted in a peak value after 1 h (73.5±8.0 ng ml^–1). At both temperatures levels remained significantly elevated (p<0.05) for the entire period of exposure. Increased temperature also resulted in a significant change in haemoglobin, haematocrit and mean cell haemoglobin concentration (MCHC) (p<0.05). Plasma lactate was significantly elevated only after exposure to 8°C (p<0.05). Plasma cortisol levels fromP. borchgrevinki are reported here for the first time and show this cryopelagic Antarctic species to have an unusual hormonal stress profile.     

Role of calcium in the histamine release induced by D-galactosamine from rat mast cells

Summary Rat peritoneal mast cells were isolated and purified by differential centrifugation in Ficoll. Cells pooled from three to four rats were suspended at approximately 10⁶ cells/ml in a buffered salt solution and incubated for 1 h at 37°C in 300 l volumes in the absence or presence (9×10^–4 M) of calcium chloride. Addition of D-galactosamine hydrochloride (DGM; 2.8×10^–4 M) caused (in addition to basal release) a mean ±SEM percent histamine release of 15.7±5.2 in the presence of Ca⁺⁺ and 19±4.9 in the absence of Ca⁺⁺ (p>0.05). It is suggested that D-galactosamine does not require extracellular Ca⁺⁺ for the release of histamine from the rat mast cell.A preliminary analysis of these results was presented at the International Symposium on calcium entry blockers and tissue protection, Rome, 15–16 March 1984.     

The number of neurons,glial and perineurium cells in an insect ganglion

Zusammenfassung Im zweiten Abdominalganglion der Indischen Stabheuschrecke (Carausius morosus Br.) wurden 600 ± 50 Neurone, 1000 ± 100 Gliazellen und 500 ± 30 Perineuriumzellen, zusammen etwa 2100 Zellen gezählt. Die Volumina des Ganglions, des Neuropilems und des Zellcortex betrugen etwa: 140 · 10^–4 mm³, 75 · 10^–4 mm³ und 65 · 10^–4 mm³.     

Cellular responses to mild heat stress

Since its discovery in 1962 by Ritossa, the heat shock response has been extensively studied by a number of investigators to understand the molecular mechanism underlying the cellular response to heat stress. The most well characterized heat shock response is induction of the heat shock proteins that function as molecular chaperones and exert cell cycle regulatory and anti-apoptotic activities. While most investigators have focused their studies on the toxic effects of heat stress in organisms such as severe heat stress-induced cell cycle arrest and apoptosis, the cellular response to fever-ranged mild heat stress has been rather underestimated. However, the cellular response to mild heat stress is likely to be more important in a physiological sense than that to severe heat stress because the body temperature of homeothermic animals increases by only 1–2°C during febrile diseases. Here we provide information that mild heat stress does have some beneficial role in organisms via positively regulating cell proliferation and differentiation, and immune response in mammalian cells.Received 14 May 2004; received after revision 2 August 2004; accepted 16 August 2004     

Das bioelektrische Potential an der zytoplasmatischen Membran der Granulozyten

Summary The bioelectric potential between the interior of granulocytes taken from whole blood and exudatleucocytes and 2 extracellular media was examined with microelectrode-technique. The order of magnitude amounts to about – 5 mV. The potentials of the cell population are Gaussian distributed.

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Frl. D.Lüders sind wir für die sehr sorgfältig durchgeführten Zellpunktionen und Potentialmessungen sowie für die Herstellung der Mikroelektroden zu grossen Dank verpflichtet.     

Asscorbic acid portects against male infertility in a teleost fish

An animal unable to synthesize ascorbic acid uniquely minicks human and non-human primates. Therefore, in this study we used the rainbow trout, a teleost fish, as the model animal to study the importance of dietary ascorbic acid on the fertilizing ability of sperm. A high concentration of ascorbic acid in semen plays a key role in maintaining the genetic integrity of sperm cells, by preventing oxidative damage to sperm DNA. This study will show that the concentration of asorbic acid in seminal plasma refelcts the dietary fed either an ascorbate-free diet (from 4.74±0.9 to 0.16±0.08 g ml^–1) or an ascorbate-rich diet (from 37.9±4.7 to 17.7± 3.2 g ml^–1) during the sperimnation season. The relationship between ascrobate status and fertility was studied in six groups of fish fed graded levels of ascorbic acid, which sperimated over a 150-day-period. Sperm from individual males was used to fertilize several batches of eggs. When the seminal plasma ascorbate concentration decreased to 7.3 g ml^–1 a significant decrease of fertilization rate and the hatching rate of embryos resulted. This is the first evidence that dietary ascorbate level directly affected sperm quality and influenced male fertility in a scruvy-prone vertebrate.     

C-peptide fragments stimulate glucose utilization in diabetic rats

Studies of C-peptide cellular effects show that not only the full-length native peptide but also specific C-terminal fragments are biologically active in in vitro systems. In the present study, the effect of five C-peptide fragments and the native peptide on whole-body glucose turnover was studied in streptozotocin diabetic rats using the insulin clamp technique. Insulin was infused intravenously at 18 pmol kg^–1 min^–1 for 90 min and blood glucose concentration was clamped at 8 and 4 mM in diabetic and non-diabetic animals. A steady state was reached during the last 30 min of the study period. Rat C-peptide II and fragments comprising residues 27–31 and 28–31 were effective in augmenting glucose turnover in diabetic rats (+100% to 150%), while no significant effects were seen for segments 1–26, 11–19 and 11–15. The metabolic clearance rate for glucose during infusion of C-peptide or fragments 27–31 and 28–31 in diabetic rats was similar to that seen in non-diabetic animals. We conclude that C-terminal tetra- and pentapeptides, but not fragments from the middle segment of C-peptide, are as effective as the full-length peptide in stimulating whole-body glucose turnover in diabetic rats.Received 18 December 2003; received after revision 19 January 2004; accepted 21 January 2004     

Experimental data on the energetic flux during glycolytic oscillations in yeast extracts

Calorimetric experiments were performed on yeast extracts in which glycolytic oscillations were occurring. High metabolic fluxes coincided with low amplitudes and with high frequencies in a temperature range from 283 to 303 K, yielding an activation energy ofE _a=76.8 kJ mol^–1 and a mean Q₁₀ value of 2.5±0.4. The calorimetrically determined reaction enthalpy _fH^0, of the glycolytic catabolism of glucose revealed two distinct groups of extract preparations, with no intermediate values. The values were –107.5±28.7 kJ mol^–1 and –30.8±5.7 kJmol^–1, respectively, while –100.0 kJ mol^–1 was predicted from theoretical calculations. Kreuzberg and Betz⁶ predicted rate limiting effects of GAPDH in oscillating extracts. However, when possible effects of GAPDH on frequency, number of oscillations or total heat production were examined, no influence of increasing or reducing the initial GAPDH concentration could be found. The results are discussed with reference to existing models of glycolytic oscillations.