Renal effects of a high unsaturated fat diet in renal artery stenosis in rats

The renal effects of an unsaturated fat (UNSAT) diet in mild to moderate two-kidney, one-clip (2K1C) renovascular hypertension were evaluated. An UNSAT diet (37% by energy) prevented the development of hypertension compared to 2K1C rats fed a high saturated fat (SAT) (37% by energy) and a normal fat (CONTROL) (11% by energy) diet. Urinary sodium and fractional sodium excretion increased in 2K1C rats as compared to SHAM operated controls, regardless of the diet received. In the early weeks of the experiment (weeks 2–4 post-surgery to induce hypertension), an enhanced natriuresis occurred in the 2K1C UNSAT as compared to the 2K1C CONTROL and SAT diet groups. This resulted from an increase in the glomerular filtration rate (GFR in mls·min^–1) as measured using the single-injection [⁵¹Cr] EDTA method (2K1C UNSAT; 1.99±0.18 versus 2K1C SAT; 1.27±0.09, p<0.02; and versus SHAM CONTROL; 1.45×0.01; p<0.02). The increased GFR was not associated with alterations in effective renal plasma flow (ERPF) as measured using the single-injection [¹²⁵I] Na hippurate method. No differences in sodium excretion; GFR; ERPF or renal blood flow (microsphere technique) were noted between the 2K1C UNSAT and SAT diet groups at weeks 6–8 post-surgery, despite a continued antihypertensive effect of the UNSAT diet. Hence, the antihypertensive effect of an unsaturated fat diet in 2K1C renovascular hypertension in rats is associated with transient glomerular changes leading to an enhanced natriuresis.     

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     

Der Sauerstoffumsatz der Leber von Ratten während der Höhenakklimatisation

Summary The O₂-consumption of liver tissue of male rats of different ages during the first 10 days at an altitude of 3540 m was significantly decreased on the 5th and 7th day. The deviation from the controls at ground level was – 19% in 40-day-old and – 30% in 11-month-old male rats.

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Auslandsstipendiat der Schweizerischen Regierung (1963–64). Für die Überlassung eines Laboratoriums und der Apparate möchte ich Herrn Prof.A. v. Muralt auch an dieser Stelle danken.

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Die Arbeit wurde unterstützt von der Max-Planck-Gesellschaft zur Förderung der Wissenschaften, Deutschland. Ein Teil der Versuchstiere wurde uns freundlicherweise von der Hoffmann-La Roche AG, Basel, durch Herrn Dr.Loosli, Füllinsdorf (BL) zur Verfügung gestellt.     

Lack of pressor effect of dopamine in the pentobarbital-anesthetized rat

Summary The blood pressure and heart rate responses to intravenous dopamine infusion at 2.5, 5.0 and 10.0 g·min^–1·100 g^–1 were studied in conscious and pentobarbital-anesthetized Sprague — Dawley rats. In the conscious rats, dopamine caused a significant dose-related increase in the mean arterial blood pressure which was abolished in the anesthetized rats. The heart rate increased significantly only at the highest dose infused. The responses to equipressor doses of noradrenaline (40 ng·min^–1·100 g^–1) and phenylephrine (1.0 g·min^–1·100 g^–1) were also suppressed in the anesthetized rats. The results suggest that pentobarbital anesthesia depresses the blood pressure response to dopamine infusion in the rat through a depression of activation of alpha-adrenoceptors.16 June 1986     

Chromosomal abnormalities in starved and marginally malnourished rats and in utero upon rehabilitation

The effects of starvation and marginal malnutrition (MN) on the lymphocytes of rats were evaluated by chromosomal analysis before and after rehabilitation. The effect of parental starvation or malnutrition on chromosomal aberrations in the foetus was also studied. Wistar rats, 30–35 days old, were starved for 5 days or fed a minimally restricted or a severely restricted diet for three weeks. At the end of the period of starvation or malnutrition, lymphocytes were isolated and chromosomal analysis was performed. Starved and severely restricted rats showed significantly higher mean chromosomal aberrations than the controls. These aberrations returned to a normal level when the experimental groups were rehabilitated for a month, indicating that the damage was transient. A chromosomal aberration study done on foetal cells from rehabilitated rats which had previously been starved or fed a severely restricted diet showed significantly increased values, indicating that some damage was permanent. A low number of implantations was also recorded in these experimental groups. These observations clearly indicate that young animals exposed to conditions like starvation or chronic malnutrition are prone to permanent damage of the genetic system.     

Effect of diabetes on the vertebral column of rats and its modification by estradiol

Summary In vertebrae of genetically selected sucrose-fed diabetic rats a statistically significant bone deficit was found after diabetes had been present for about 8 months. No osteopenia was observed in diabetic rats following treatment with estrogenic hormone for 5–7 months. The development of osseous centers in the end plates of the vertebrae was retarded in diabetic rats, but was about normal in diabetic rats given estrogen.—No differences were noted in the growth zones or in the tendency to develop articular lesions in rats of the various groups. Possible differences in the amount of GAG in intervertebral discs of diabetic and non-diabetic rats respectively await further confirmation.These investigations were aided by grant No. 2 RO1 EYO 1837-03, of the Institute of Arthritis and Metabolic Disease, National Institutes of Health, Bethesda, Maryland, USA.We are indebted to Professor Dr J. Rüttner, Institute of Pathology, University of Zürich, for his permission to use the calculator.     

Modification of the action of pentagastrin on acid secretion by botulinum toxin

Summary I.v. botulinum toxin after 60–90 min abolished the dose-response relationship between pentagastrin and gastric acid secretion in anesthetized rats and guinea-pigs. The toxin reduced but did not abolish the acid stimulatory effect of histamine. As expected, the acid response to vagal stimulation was abolished and that to methacholine in rats was unaltered by the toxin.Acknowledgment. We are grateful to the generosity of Dr Edward J. Schantz, Food Research Institute, University of Wisconsin, for the botulinum toxin used. — This research was supported by NIH grant 1 RO1 AM 17125, The Secretion of Pepsin.     

Effect of tea consumption on the levels ofα-ketoglutarate and pyruvate dehydrogenase in rat brain

Summary Administration of tea to rats fed on a normal diet results in a marked drop in brain levels of total thiamine as well as of -ketoglutarate and pyruvate dehydrogenase activities. The patterns of decrease in both enzyme activities are similar to that of total thiamine content; they drop to about 65% of the control at 14–20 weeks after continuous consumption of tea.Supported by a grant from the International Foundation for Science (IFS), Sweden.     

Neutron activation analysis of saliva from the tickAmblyomma variegatum

Summary The hygroscopic saliva produced by fastingAmblyomma variegatum adults during prolonged exposure to dry air was found to contain sodium, potassium and chlorine in molar proportions of 1.1–1.7–3.8 respectively, or proportions by dry weight of 8, 21 and 41%. These values are quite different from those reported previously for saliva from recently fed ixodid ticks. TheA. variegatum saliva contained, by dry weight, less than 5% sulphur and less than 1.5% each of phosphorus, calcium, magnesium and iron.Acknowledgments. I wish to thank Prof. W. Knülle for extending to me support granted by the Deutsche Forschungsgemeinschaft, and Dr D. Rudolph for providing the saliva solids.     

Age and evolution of bacteria

Summary Age and evolution of bacteria can be estimated, including facts and hypotheses belonging to morphology, biochemistry, paleontology, ecology and pathogenicity. The corresponding dates are summarized in the following.About 3.5×10⁹ years: Origin of heterotrophic eobiontes.—About 3.0×10⁹ years: The increasing lack of prebiogenic substances is due to the evolution of the respiratory pathway, that is due to the evolution of the photoautotrophy and now released O₂ is due to the evolution of strictly aerobic cells. There is, simultaneously, a transition of spheres to long forms, development of an amoebalike motility, the evolution of spirochetes and the substitution of cholesterol for cardiolipin in the more evolved cells (i.e. strictly aerobic cells etc.).—About 2.0×1.0×10⁹ years: Evolution of the eucyte by symbiosis of a great, primitive, anaerobic, cholesterol-containing cell with a little, strictly aerobic, cardiolipin-containing cell, with a spirochete and in some extent also with photoautotrophic cell.—About 1.0×10⁹ years (maximum: 1.8–1.5×10⁹ years, minimum: 7×10⁸ years): Evolution of metazoa and begin of cell differentiation.—About 2.0–1.0×10⁹ years: Evolution of the bacterial murein sacculus and then development of flagella mediated motility.—About 6×10⁸ years (maximum:1.0×10⁹ years, minimum: 4.5×10⁸ years): Evolution of the gram-negative cell wall.—About 4.0×10⁸ years: Evolution of the gram-positive cell wall.—About 5.0×10⁸ years: Gram-negative, strictly anaerobic bacteria become the first enteric bacteria in coelenterates. About 4.0×10⁸ years: gram-negative, microaerophilic bacteria become Enterobacteriaceae in vertebrates in addition to the strictly anaerobic organisms.—About 3.0–2.0×10⁸ years: Consolidation of the Salmonella in reptiles.—About 2.0–1.5×10⁸ years: Consolidation of Escherichia and other coliform species in mammals.—About 10⁶ years: Evolution of typically human pathogenic organisms, transmitted in homogeneous-homonomous infection ways, i.e. N. gonorrhoeae, S. typhi, T. pallidum, etc.Dedicated to Prof. H. Habs, Bonn, to his 75th anniversary on 11 September 1977.Acknowledgment. I thank Prof. F. Müller, Hamburg, and Prof. P. Sitte, Freiburg i. Br., for stimulating discussions.     

Veränderungen in der Mitochondrienfraktion der Rattenleber nach Total- und Leberfeldbestrahlung (1000 r)

Summary A study was made of the influence of local (liver field) and total irradiation (1,000 rl) on the enzymatic activity of isolated liver mitochondria from adult rats. While the succinodehydrogenase activity remains unaltered, the oxydation of pyruvate — as well as the structural stability of the mitochondria — are found to be reduced, entailing a decrease in the oxydative phosphorylation. These variations remain the same even after total or local irradiation.     

Choleretic and cholestatic effects of infused bile salts in the rat

Summary In rats, at low infusion rates taurocholate (TC), taurochenodeoxycholate (TCDC) and taurodeoxycholate (TCD) each produced an increase in bile flow of 20–50%. However, at high infusion rates (5–20 moles min^–1 kg^–1) the cholestatic effects of the bile salts were revealed and the relative toxicity of the bile salts was seen to be TDC>TCDC>TC.     

Captopril (SQ 14,225): In vitro and in vivo influence on the proliferative response of rat lymphocytes

Summary Captopril in vitro (50–500 g/ml) increased³H-TdR incorporation in unstimulated and mitogen-stimulated cultures of rat lymphocytes. Unseparated spleen and lymph node cells of rats orally treated with captopril (50 mg/kg/day×4) showed decreased basal and mitogen stimulated³H-TdR incorporation. The removal of macrophages abrogated this inhibitory effect. Leucine aminopeptidase activity of macrophages was reduced — in vivo and in vitro — by captopril.Acknowledgments. The authors thank the Squibb Institute for Medical Research for the gift of Captopril. The excellent technical assistance of Ms B. Hasselriis, Ms B. Rumler and Ms E. Greve Petersen is gratefully acknowledged.     

Plasma prostaglandin levels in fed and starved lean,normal and obese women

Summary The plasma obtained from fed and starved lean, normal and obese women was estimated, by a radio-immunoassay method, for prostaglandins, owing to their implication in the regulation of adipose tissue lipolysis and the development of obesity. No significant differences were found due to nutritional status or body-build. However, a significantly higher plasma concentration of prostaglandins of the E-type than of the F-type, was found consistently. The very low levels of prostaglandins observed (a range of 0.10–0.15 ng ml^–1 for E-type and a range of 0.05–0.07 ng ml^–1 for the F-type) may be due, in part, to the activity of a plasmatic prostaglandin metabolizing system.Acknowledgments. The authors are grateful to Dr D.C. Williams for his support and encouragement and to the Upjohn Company for the generous gift of standard prostaglandins.     

Vegetation structure and primary production in acidified lakes in southwestern Sweden

Summary Research during the last two decades has clearly pointed out that dramatic ecosystem changes have occured in lakes due to deposition of acid substances and decreased pH. Today a large number of lakes and running waters in Scandinavia are suffering biological damage with disappearing fish populations, overgrowth of the bottom by mosses and filamentous algae, reduced invertebrate fauna, increased transparency etc.—Of all documented biological changes the effect on macrophyte succession, in particular that ofSphagnum, is the most striking effect. Along with the growth of filamentous algae, these changes have brought about major shifts in the composition of the primary producers. The biomass in one lake was estimated to be 6.5 t (dry wt) corresponding to about 24 g m^–2, the relevant proportions being 52% forSphagnum, 34% forLobelia and 15% forIsoetes. Percentage production in the whole lake is 54% forSphagnum, 29% forLobelia and 17% forIsoetes, which gives an estimated production of 2.9 t yr^–1 or 9 g m^–2 yr^–1.Sphagnum is a recent flora element and its occurrence is related to the acidification of the lakes. The investigations also show that the growth ofLobelia is reduced in acid lakes compared to other oligotrophic lakes due to shading by the benthic mat of filamentous algae, detritus andSphagnum debris.—One can conclude that there are several quantitative and qualitative changes in the macrophyte community which are related to acidification. One can also conclude that liming of lakes cause elimination ofSphagnum and some increase in the production ofIsoetids.     

An analysis of the effects of urethane on cardiovascular responsiveness to catecholamines in terms of its interference with Ca++ mobilization from both intra and extracellular pools

Summary Urethane (1×10^–2–1×10^–1 M) reduced, in a concentration-dependent manner, both intra and extracellular Ca⁺⁺ dependent noradrenaline-induced contractions of perfused rabbit ear artery as well as the tonic contractions produced by perfusion with high K⁺ solution. However, a quantitative analysis of the data indicated that for urethane concentrations similar to those found in plasma during anesthesia urethane antagonism is confined to noradrenaline-induced contractions which depend upon the mobilization of Ca⁺⁺ from intracellular storage sites. In KCl-contracted arteries, urethane enhanced the relaxant effects of isoprenaline.—Urethane reduced the amplitude of contractions of spontaneously beating guinea-pig right atrium at concentrations which have only a limited effect on frequency. In addition, it decreased in a concentration-dependent manner the amplitude of isoprenaline-activated electrically driven, and K⁺ depolarized guinea-pig right ventricular strips. Urethane had no effect on the chrono and inotropic actions of isoprenaline on cardiac preparations. In in vivo experiments the chronotropic response to low doses of isoprenaline was significantly higher in urethane-treated as compared to unanesthetized rats. The higher dose of isoprenaline tested produced a significant fall in systolic blood pressure in urethane-anesthetized rats. A significant correlation exists between the chronotropic response to isoprenaline and resting heart rate values in urethane-anesthetized rats. These results indicate that urethane, at concentrations similar to those found in plasma during anesthesia selectively interferes with mobilization of Ca⁺⁺ from intracellular storage sites. In addition, the interference of urethane anesthesia with the isoprenaline chronotropic effect in vivo cannot be explained by a direct interference of urethane with -adrenoceptors at cardiac level.     

pH-dependent action of NaCl on isolated guinea pig's ileum

Riassunto L'NaCl, aggiunto a un bagno — in cui è sospeso un frammento di ileo di cavia — sino a concentrazioni finali comprese fra 2·10^–3 e 10^–2, agisce come contratturante a pH=8,0 e come antagonista competitivo dell'acetilcolina e dell'istamina a pH=5,3.     

Age variation in the increase of hypothalamic and brain stem contents of phenylethanolamine m-octopamine and p-octopamine in spontaneously hypertensive rats (SH kyoto)

Summary Phenylethanolamine, m=octopamine and p-octopamine contents were determined as a function of age in the hypothalamus and brain stem of spontaneously hypertensive rats and controls Wistar Kyoto. In hypothalamus, the content of the 3 amines was 2–4-fold greater for the SH rats. In the brain stem, the phenylethanolamine and p-octopamine contents were 2–3-fold greater in SH rats but 5–6-fold higher in the case of m-octopamine. The difference appears at 3 weeks and correlates the blood pressure with the increase of age. The significance of these findings is discussed.This work has been completed at the Tokyo University. The author is grateful to Professor Z. Tamura, Dr K. Imai and A. Ooshima as well as to the French Foreign Office and the Japanese Society for the Promotion of Sciences.     

The activation of membrane ATPase by ouabain in several tissues of the golden hamster (Mesocricetus auratus) in the absence of potassium

Summary The activity of the membrane ATPase of 5 organs of the golden hamster was increased by 10^–7–10^–3 moles/l ouabain in K⁺-free medium. In similar experiments on rats no increase was observed.     

A simple method for the preparation of antibodies to the mitochondrial biotin-dependent carboxylases

Summary Heterologous antiserum to the 3 biotin-dependent carboxylases was prepared by selective removal of these enzymes from human liver on an avidin-sepharose column. A carboxylase-avidin-sepharose matrix was used as an antigen to produce anti-carboxylase antibodies. The resultant antisera can be used to purifiy the specific carboxylases, to prepare monoclonal antibodies to these enzymes or to study inherited carboxylase deficiencies and biotin-dependent intermediary metabolism.The authors thank Dr Emmanuel Shapira for his helpful suggestions and Patricia Tuck for her technical assistance. This work was supported by NIH research grants AM25675 and AM26127. Barry Wolf is a recipient of an NIH Research Career Development Award (AM00677) and is aided by a Basil O'Connor Starter Research Grant from the National Foundation—March of Dimes (5–263). This is paper No. 137 from the Department of Human Genetics — Medical College of Virginia.