Relationship between light diffraction intensity and tension development in frog skeletal muscle

Summary Laser diffraction intensity decrease in active muscles precedes tension development at sarcomere lenghts below 2.76 m, but not at greater lenghts. This suggests that the time lag is caused by random sarcomere shortenings inside each myofibril.     

Changes in the A-band width during contraction in horseshoe crab striated muscle

Summary Cinematographic recordings of Ca-activated contraction in glycerinated bundles of myofibrils of the horseshoe crab striated muscle indicated that the A-band width did not change during rapid sarcomere shortening from 11 to 4 m, while it increased by about 10% in nearly isometric conditions.We wish to thank T. Taniguchi, M. Kusama and M. Goto for their excellent technical assistance in taking cinematographic recordings.     

Bestimmung des α-2-Makroglobulinumsatzes beim Menschen

Summary The turnover of ₂-macroglobulins was measured by quantitative precipitation of the I¹³¹-marked protein, using a specific antiserum. In 6 normal persons, the half-life was found to be between 192 and 267 h. The catabolic rates in relation to the intravascular pool range between 437 and 703 mg/day

---

---

Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Administration by nasal spray of an 18 amino acid synthetic polypeptide with corticotropic action

Résumé L'administration en nébulisation nasale d'un peptide synthétique corticotrope: [D-Sér¹, Lys^17,18]--corticotrophine-(1–18)-octadécapeptide amide (CIBA 41,795-Ba), s'est montrée parfaitement efficace et a élevé le taux des corticoÏdes plasmatiques chez des volontaires normaux. La relation dose-réponse s'est montrée très satisfaisante.     

Preparation of isolated single cardiac cells from adult frog atrial tissue

Summary Isolated cardiac cells from bullforg atrial tissue can be readily prepared by digestion of intact fragments of atrial tissue with trypsin and collagenase. These isolated cells have dimensions of about 5 m in width and range in length from 300 m to over 500 m. Such isolated cells may prove useful for the investigation of contractile activity of cardiac muscle at the single cell level and at the sarcomere level within the single cell.This investigation was supported by U.S. Public Health Service, National Institutes of Health Grant No. HL 12426 and a Kansas Heart Association Grant-in-Aid.We wish to thank Dr.J. Sommers of Duke University Medical Center for doing electron microscopy of the isolated cells to confirm the single cell nature of the preparations.     

Intraspezifische Unterschiede der relativen Hirngrösse beim Löwen (Panthera leo L.)

Summary Different stages of brain evolution expressed by the allometric relation of³ brain capacity and basal length of the skull are shown to be existent in the speciesPanthera leo. Whereas Asiatic lions obviously have the same level of brain size as leopards (Panthera pardus), African lions have higher brain capacities. A third level seems to be represented by the upper pleistocene American lion,Panthera leo atrox. These results permit us to reject some conceptions ofHerre andRöhrs ¹³ concerning the quantitative expression of mammalian brain evolution.     

Maternal vitamin A restriction alters biochemical development of the brain in rats

Summary The biochemical development of the fetal brain in relation to maternal vitamin A restriction was studied in rats. The vitamin A status of pregnant rats was varied by supplying low, medium and adequate amounts (6, 40, and 100 g retinol/day/kg body weight, respectively) of vitamin A during pregnancy and suckling. The maternal vitamin A restriction caused an altered brain development in terms of tissue weight, DNA, RNA and protein levels, and biosynthesis of DNA and protein from [³H]-thymidine and [³H]-leucine, respectively. A dose-dependent effect of maternal vitamin A restriction on the metabolism of DNA, RNA and protein was noticed in the developing fetal brain of rats.     

The free radical oxidation of the tetrahydrocannabinols

Summary The free radical oxidation of ¹ and ⁶-tetrahydrocannabinol has been examined by spin trapping techniques and intermediates that would lead to cannabinol have been trapped. The 1st step in the oxidation of ¹-THC involves the removal of 3-H, while for ⁶-THC, either 2-H or 5-H. Intermediates were isolated which could be pyrolysed to the diene and cannabinol.     

Potentiating action of hexoprenaline on14C-aminopyrine uptake by isolated rat parietal cells

Summary Hexoprenaline potentiated the¹⁴C-aminopyrine uptake (a reliable index of H⁺ generation) of isolated rat gastric cells stimulated by 10^–6–10^–4 mol/l carbachol, and inhibited that in response to 10^–4 mol/l histamine without and in the presence of propranolol. It is concluded that hexoprenaline acts as a partial agonist on parietal cell H₂-receptors and that -adrenoceptor activation may functionally modualte gastric acid secretion.Acknowledgments. S. Maliski, Institute of Rheumatology, Warszawa, held a fellowship of the Alexander v. Humboldt-Foundation. The study was supported by the Deutsche Forschungsgemeinschaft. The skilful technical assistance of Mrs R. Maier and Mr R. Beer is gratefully acknowledged.     

Tissue protection against oxidative stress

We used an enhanced luminescence technique to study the response of rat tissues, such as liver, heart, muscle and blood, to oxidative stress and to determine their antioxidant capacity. As previously found for liver homogenate, the intensity of light emission (E) of tissue homogenates and blood samples, stressed with sodium perborate, is dependent on concentration, and the dose-response curves can be described by the equation E=a·C/exp(b·C). Theb value depends on the antioxidant defence capability of the tissues. In fact, it increases when homogenates are supplemented with an antioxidant, and is correlated with tissue antioxidant capacity, evaluated by two previously set up methods both using the same luminescence technique. Our results indicate that the order of antioxidant capacity of the tissues is liver>blood>heart>muscle. Thea value depends on the systems catalysing the production of radical species. In fact, it is related to the tissue level of hemoproteins, which are known to act as catalysts in radical production from hydroperoxides. The equation proposed to describe the dose-response relation is simple to handle and permits an immediate connection with the two characteristics of the systems analysed which determine their response to the pro-oxidant treatment. However, the equation which best describes the above relation for all the tissues is the following: E=·C/exp(·C). The parameter assumes values smaller than 1, which seem to depend on relative amounts of tissue hemoproteins and antioxidants. The extension of the analysis to mitochondria shows that they respond to oxidative stress in a way analogous to the tissues, and that the adherence of the dose-response curve to the course predicted from the equation E=a·C/exp(b·C) is again dependent on hemoprotein content.     

C-peptide stimulates Na<Superscript>+</Superscript>, K<Superscript>+</Superscript>-ATPase via activation of ERK1/2 MAP kinases in human renal tubular cells

Proinsulin-connecting peptide (C-peptide) exerts physiological effects partially via stimulation of Na⁺, K⁺-ATPase. We determined the molecular mechanism by which C-peptide stimulates Na⁺, K⁺-ATPase in primary human renal tubular cells (HRTCs). Incubation of the cells with 5 nM human C-peptide at 37°C for 10 min stimulated ⁸⁶Rb⁺ uptake by 40% (p<0.01). The carboxy-terminal pentapeptide was found to elicit 57% of the activity of the intact molecule. In parallel with ouabain-sensitive ⁸⁶Rb⁺ uptake, C-peptide increased subunit phosphorylation and basolateral membrane (BLM) abundance of the Na⁺, K⁺-ATPase ₁ and ₁ subunits. The increase in BLM abundance of the Na⁺, K⁺-ATPase ₁ and ₁ subunits was accompanied by depletion of ₁ and ₁ subunits from the endosomal compartments. C-peptide action on Na⁺, K⁺-ATPase was ERK1/2-dependent in HRTCs. C-peptide-stimulated Na⁺, K⁺-ATPase activation, phosphorylation of ₁-subunit and translocation of ₁ and ₁ subunits to the BLM were abolished by a MEK1/2 inhibitor (20 M PD98059). C-peptide stimulation of ⁸⁶Rb⁺ uptake was also abolished by preincubation of HRTCs with an inhibitor of PKC (1 M GF109203X). C-peptide stimulated phosphorylation of human Na⁺, K⁺-ATPase subunit on Thr-Pro amino acid motifs, which form specific ERK substrates. In conclusion, C-peptide stimulates sodium pump activity via ERK1/2-induced phosphorylation of Thr residues on the subunit of Na⁺, K⁺-ATPase.Received 15 June 2004; received after revision 14 September 2004; accepted 14 September 2004     

Induction of lymphokine-activated killer cells from nude mouse spleen cells by interleukin-4

The induction of lymphokine-activated killer (LAK) cells from natural killer (NK) lineage cells by interleukin-4 (IL-4) was studied in vitro. Activation of nude mouse spleen cells by IL-4 generated cytotoxic cells, capable of killing NK-sensitive as well as NK-resistant tumor cells. The induction of peak lytic activity was demonstrated after 3 days of culture with IL-4. Surface marker analysis indicated that the majority of precursor cells were aGM1⁺, Thy1^–, and the majority of effector cells were aGM1⁺, Thy1⁺, suggesting that IL-4 induced LAK cells from nude mouse spleen cells were similar to those from normal mouse spleen cells. The induction of nude mouse LAK cells by IL-4 was partially inhibited by anti-IL-4 or anti-interferon (IFN)-, antibody, and it was further inhibited by the combination of two antibodies, suggesting that IFN-, production was associated with LAK induction of NK lineage cells by IL-4.     

Inhibition of hepatic Na+, K+-adenosinetriphosphatase in taurolithocholate-induced cholestasis in the rat

Summary Na⁺, K⁺-adenosinetriphosphatase (Na⁺, K⁺-ATPase) activity was decreased in liver plasma membranes from rats in which cholestasis had been induced by i.v. administration of sodium taurolithocholate (5 moles/100 g b. wt). Incubation of liver plasma membranes with taurolithocholate (10–1300 M) caused significant and dose dependent reductions of Na⁺, K⁺-ATPase activity at taurolithocholate concentrations above 100 M. These findings lend support to the hypothesis that cholestasis induced by monohydroxy bile acids is at least partially the result of an inhibition of hepatic Na⁺, K⁺-ATPase activity.This work was supported by the Swiss National Science Foundation.The authors thank Mr H. Sägesser and Miss B. Schütz for technical assistance.     

Inhibition of human testicular glucose-6-phosphate dehydrogenase by unsaturated C19-steroids

Zusammenfassung Die Bebrütung einer gereinigten G-6-PDH aus menschlichem Testisgewebe mit 3-substituierten ⁴- oder ⁵-C₁₉-Steroiden zeigte, dass 3-Hydroxy-⁴-oder ⁵-androsten-17-on auch wirksame Inhibitoren der testikulären G-6-PDH darstellen. Zur gleichen Zeit konnten die früher gefundenen Zusammenhänge zwischen chemischer Struktur eines Steroids und seiner biologischen Aktivität im G-6-PDH-Hemmtest uneingeschränkt bestätigt werden.     

Cu2+-Adeninring-Wechselwirkung in den Cu2+-Komplexen von Adenosin-5′- und Adenosin-3′-monophosphat

Summary By means of UV and NMR spectroscopy evidence is given for direct interaction between metal ion and heteroaromatic groups in both Cu²⁺-adenosine-5-monophosphate and Cu²⁺-adenosine-3-monophosphate complexes. A comparison with the Cu²⁺-adenosine system shows that this interaction is much enhanced in the monophosphate analogues, which points to the existence of a macrocyclic phosphate-metal-adenine chelate.     

Isotope effect studies on the dehydrogenation of Δ1-tetrahydrocannabinol in the rat

Summary Isotope effect studies on the metabolic dehydrogenation of ¹-tetrahydrocannabinol in rats are described and its is shown that this process is confined to a very short period following i.v. administration. The implications of this finding are discussed.The authors are grateful for generous fifts of³H-¹-THC from Dr S. Burstein (Worcester Foundation for Experimental Biology, Massachusetts), and of¹⁴C-¹-THC from the National Institute on Drug Abuse. The authors thank the staff of the Small Animal Unit, Wallaceville Research Centre for their cooperation, and the U.S. National Institute on Drug Abuse for their support.     

Effect of acute administration of Δ1-tetrahydrocannabinol on β-endorphin levels in plasma and brain tissue of the rat

Summary Acute treatment with ¹-tetrahydrocannabinol (¹-THC) elevated the concentration of -endorphin-like immunoreactivity (-ELIR) in plasma and in the hypothalamus, but not in the hippocampus of rats habituated to the injection procedure. These effects were not obtained with the psychotropically inert analog of (¹-THC), cannabidiol. In animals that had not been habituated to the injection procedure, placebo treatment induced a decrease in hippocampal -ELIR.The authors acknowledge the skillful technical assistance of Mrs Willeke Logtenberg.     

Activité antifibrillante chez l'animal d'un nouveau dérivé de la phényl-éthylamine

Summary A new synthetic phenyl-ethyl-amine derivative, the 2-[N- (3, 4-methylen-dioxyphenylethyl)-methylaminomethyl]-tetrahydrofuran, No. 11 081, exhibits a strong protective effect against cardiac fibrillation and arrhythmias produced by various experimental methods: against fibrillation due to aconitine 3 × 10^–8 on the isolated cat's heart, it is active in a concentration of 10^–6–2 × 10^–6. Against cardiac arrhythmias produced in the cat by adrenaline + CHCl₃ or cyclopropane, it shows a protective effect by 5–10 mg/kg i.v. and even perorally by 50 mg/kg. In these tests, the antifibrillatory activity of the new compound seems to be roughly the same as that of -fagarine, and higher than that of procaine.

---

---

9^e communication sur les dérivés des alcoylène-imines; 8^e communication, cf. Exper.10, 261 (1954).     

Cl−/HCO 3 − exchanger is operative in isolated enterocytes from rat jejunum

Enterocytes isolated from rat jejunum were tested for the existence of a Cl^–/HCO ₃ ^– exchange, previously evidenced in basolateral membrane vesicles but not in brush border. Cells were found to retain functional integrity and transport capabilities long enough to allow Cl^– fluxes to be measured. Both efflux and uptake experiments indicate that a Cl^–/HCO ₃ ^– antiport, inhibited by 4,4-diisothiocyanostilbene-2-2-disulfonic acid (DIDS), is functional under resting conditions.     

Unterschiedliche Empfindlichkeit verschiedener Angiotensinderivate gegen Abbau durch Plasma oder Nierenhomogenat

Summary -Asp¹-Angiotensin II had a more pronounced action on the blood pressure of nephrectomized rats than the corresponding-compound.-Asp¹-Angiotensins were more slowly destroyed by rat serum, rat kidney homogenate, and human plasma than-compounds, especially-Asp¹-Angiotensin II amide.