Cadmium-induced changes in renal hemodynamics in the domestic fowl

Low i.v. doses of cadmium chloride (15 micrograms Cd) given to pullets resulted in a significant reduction in urine flow (UF), glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). However, in hens treated with the heavy metal chelate FeNa EDTA prior to cadmium treatment no oliguria or reduction in GFR or ERPF was observed. It is suggested that the renal changes following the i.v. administration of cadmium to diuretic hens and alleviated in hens primed with the heavy metal chelate may result from changes in glomerular hemodynamics.     

Acute effects of tolamolol on renal function in hypertensive patients.

The renal heamodynamic effects of a single i.v. administration of tolamolol were studied in 9 hypertensive subjects. No change of GFR and ERPF was observed after tolamolol, while urine output decreased and urine creatinine concentration increased. A reduction of the heart rate was confirmed. Blood pressure was unchanged.     

Acute effects of tolamolol on renal function in hypertensive patients

The renal haemodynamic effects of a single i.v. administration of tolamolol were studied in 9 hypertensive subjects. No change of GFR and ERPF was observed after tolamolol, while urine output decreased and urine creatinine concentration increased. A reduction of the heart rate was confirmed. Blood pressure was unchanged.     

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.     

Metal accumulation inAgaricus bisporus: Influence of Cd and Cu on growth and tyrosinase activity

Summary To investigate heavy metal uptake in the common mushroomAgaricus bisporus, commercial cultures of the fungus were exposed to different amounts of copper ad cadmium. In contrast to copper, cadmium already exerted pronounced toxic effects at low concentrations (>10 M) in the compost and concomitantly enhanced the uptake of copper. Tyrosinase activity measured in the fruit bodies increased sharply, when small amounts of Cd (10 M) were added to copper-rich compost. Gel filtration experiments with crude extracts from fruit bodies demonstrated the absence of a low molecular weight metal binding protein.Acknowledgments. This work was supported by the Schweizerischer Nationalfonds grant 3.420–0.78 (to K.L.) and by Hauser Champignonkulturen AG. We are indepted to Dr D. Rast for helpful discussions.     

Cadmium-induced changes in avian renal morphology

Summary The effects of i.m. administered cadmium on growth rate and nephromorphology were studied in young pullets. The growth rate of pullets treated with 0.6 mg Cd²⁺/kg at 48-h intervals was severely retarded, reaching only 50% of normal growth by 21 days. Such a decrease in growth rate was prevented when cadmium was given with either ferric or magnesium EDTA chelate. Electron micrographs of kidney tissue from cadmium intoxicated birds revealed massive intracellular disorganisation of proximal tubular cells, showing increased vacuolation and dilated endoplasmic reticulum. Mitochondria were few and swollen with reduced cristae. Some disorganisation was noted in the group treated with MgEDTA in conjunction with cadmium, with normal morphology observed in the group treated FeEDTA plus cadmium.In general, glomerular morphology of intoxicated pullets appeared normal, except that a 25% increase in thickness of the glomerular basement membrane was evident. No such membrane thickening was observed in any of the chelate treated groups.These findings indicate that both chelates can provide certain levels of protection, in terms of growth rate and morphology, from cadmium intoxication. The possible mechanisms by which chelates offer protection have been discussed, but many questions remain unanswered.     

Dopamine and cerebral cortical blood flow in the rat

Summary Dopamine topically applied to the cerebral cortex (1–20 g/ml) or administered i.v. (0.5–64 g/kg/min) has no effects on cerebral cortical blood flow in the rat.     

Schwefel als Ligandatom in Chelatkomplexen

Summary The hitherto unknown compounds 5-(2-pyridyl)thiazole, 2-(2-thienyl)pyridine and methyl--picolyl sulphide have been synthesized. The structure of all three substances allows the formation of a chelate ring with N and S as ligand atoms. 5-(2-Pyridyl)thiazole yields with Fe²⁺ at a pH of 2.5 a significant change in absorption, which is attributed to chelate formation.     

Lithium lowers renal,cardiac and splenic ornithine decarboxylase activity in mice

Summary A single i.p. injection of lithium chloride (5–7.5 moles/g b.wt) in mice caused a 70–80% decrease in renal, cardiac and splenic ornithine decarboxylase (ODC) activity within 1 h, whereas pulmonary ODC activity was unaffected. Lithium chloride did not have any effect on ODC activity in vitro when added to homogenates of the tissues studied. We suggest that the effect of lithium on ODC activity is not direct, but mediated via e.g. hormonal or nervous influence.This study was supported by grants from the Swedish Medical Research Council (04X-02212, 14X-00028), and the Faculty of Medicine, University of Lund (Sweden).     

Biological indicators of cadmium exposure and toxicity

Summary The increasing environmental and occupational exposure of populations to cadmium creates the need for biological indicators of cadmium exposure and toxicity. The advantages and disadvantages of monitoring blood cadmium, urinary, fecal, hair, and tissue cadmium, serum creatinine, ₂-microglobulin, ₁-antitrypsin and other proteins, and urinary amino acids, enzymes, total proteins, glucose ₂-microglobulin, retinol-binding protein, lysozyme, and metallothionein are discussed. It is concluded that urinary cadmium, metallothionein and ₂-microglobulin may be used together to assess cadmium, exposure and toxicity.     

Antifertilityeffects of clonidine in laying hens

Summary Clonidine was anovulatory and markedly antigonadal in laying hens when infused for 1 week from minipump implants at daily rates of 1.08 mg per hen or greater. The ovaries of hens treated with clonidine responded to FSH injections which suggests that the antigonadal effect of clonidine resulted from a reduction in the output of gonadotropin by the pituitary. These data suggest that ₂ receptors may be important in regulating avian fertility.     

Evidence for an unusual multifunctional protoreceptor in hormone action

Summary Contrary to the techniques of mere association, column chromatography has revealed a protoreceptor that accepts aldosterone agonists and antagonists only in the physiological target, the kidney, and is absent in non-targets, liver and serum; it is furthermore different from the aldosterone specific receptor in renal cytosol.Supported in part by grants from the CNRS AI 03 1917 and UER Broussais Hôtel Dieu.     

Monoaminoguanidine prevents sorbitol accumulation,nonenzymatic protein glycosylation and development of kidney lesions in diabetic rats

Summary Monoaminoguanidine administration (25 mg/kg b.wt, i.p. for 14 weeks) to alloxan diabetic rats (blood glucose 250 mg/dl) decreased the nonenzymatic protein glycosylation and sorbitol levels. It prevented development of Armanni-Ebstein tubular lesions, pathological changes in the glomerular capillary tufts and glomerular basement membrane thickening in the kidney.CDRI Communication no. 4694.     

On the role of the decreased renal vascular resistance in the mechanism of volume natriuresis

Summary Acute hypohysectomy (AH) prevented the increase of the cardiac output, renal cortical blood flow (e.g. the decrease of the renal vascular resistance) and renal sodium excretion during the ECFV expansion. The non-occurrence of natriuresis in AH rats is suggested as being partly in causal relation to the inability to decrease the renal vascular resistance and thus to increase the peritubular hydrostatic pressure.Expert technical assistance of Mrs.E. Blaková, J. Kyselicová and Mr.. Kaloai is sincerely acknowledged.     

Influence of repeated prazosin administration on cardiovascular responses in rats and rabbits

Prazosin was injected i.v. at a dose of 50 g/kg every 2 h for 8 h in conscious rats. Its hypotensive action significantly declined. A similar effect was also observed in rabbits pretreated with prazosin (40 g/kg, i.v.) every 1 h for 4 h. In prazosin-treated rabbits, the total peripheral resistance became less responsive to phentolamine stimulation. Repeated prazosin administration abolished its ability to block receptors in a model of anococcygue muscle contraction after noradrenaline (NA) stimulation. The -adrenoceptors in anococcygue muscle exhibited lower pD₂ to NA and lower pA₂ to prazosin in prazosin-treated rats. The results demonstrate that repeated prazosin administration reduces the effectiveness of -adrenoceptors blockers.     

Cadmium-induced changes in avian renal morphology

The effects of i.m. administered cadmium on growth rate and nephromorphology were studied in young pullets. The growth rate of pullets treated with 0.6 mg Cd2+/kg at 48-h intervals was severely retarded, reaching only 50% of normal growth by 21 days. Such a decrease in growth rate was prevented when cadmium was given with either ferric or magnesium EDTA chelate. Electron micrographs of kidney tissue from cadmium intoxicated birds revealed massive intracellular disorganisation of proximal tubular cells, showing increased vacuolation and dilated endoplasmic reticulum. Mitochondria were few and swollen with reduced cristae. Some disorganisation was noted in the group treated with MgEDTA in conjunction with cadmium, with normal morphology observed in the group treated with FeEDTA plus cadmium. In general, glomerular morphology of intoxicated pullets appeared normal, except that a 25% increase in thickness of the glomerular basement membrane was evident. No such membrane thickening was observed in any of the chelate treated groups. These findings indicate that both chelates can provide certain levels of protection, in terms of growth rate and morphology, from cadmium intoxication. The possible mechanisms by which chelates offer protection have been discussed, but many questions remain unanswered.     

Failure of somatostatin to influence experimental tumor cell growth in vivo and in vitro

Summary The influence of somatostatin on tumor cell growth was studied in vivo in mice (sarcoma 180 ascites tumor and Lewis lung tumor) and in vitro on nontransformed and polyoma-transformed cell lines. 4 or 20 g/100 g of cyclic somatostatin and 4 g/100 g of linear protamin Zn-bound somatostatin were injected s.c. twice daily in the in vivo study. Cyclic somatostatin (1, 4 or 10 g/ml) was added twice daily to the cell cultures. Somatostatin administration influenced neither the survival of animals nor the growth rate of cultured cell lines. *** DIRECT SUPPORT *** A2025117 00011     

Heritable variation for aggression as a reflection of individual coping strategies

Evidence is presented in rodents, that individual differences in aggression reflect heritable, fundamentally different, but equally valuablealternative strategies to cope with environmental demands. Generally, aggressive individuals show an active response to aversive situations. In a social setting, they react with flight or escape when defeated; in non-social situations, they react with active avoidance of controllable shocks and with sustained activity during an uncontrollable task. In contrast, non-aggressive individuals generally adopt a passive strategy. In social and non-social aversive situations, they react with immobility and withdrawal.A main aspect of these two alternative strategies is that individuals with an active strategy easily develop routines (intrinsically determined behaviour), and consequently do not react (properly) to minor changes in their environment, whereas in passively reacting animals it is just the other way around (extrinsically determined behaviour). It has become clear that active and passive behavioural strategies represent two different, but equivalent, coping styles. The coping style of the aggressive males is aimed at the removal of themselves from the source of stress or at removal of the stress source itself (i. e. active manipulation). Non-aggressive individuals seem to aim at the reduction of the emotional impact of the stress (i.e. passive confrontation). The success of both coping styles depends upon the variability or stability of the environment. The fact that aggressive males develop routines may contribute to a fast excution of their anticipatory responses, which is necessary for an effective manipulation of events. However, this is only of advantage in predictable (stable) situations, but is maladaptive (e.g. expressed by the development of stress pathologies) when the animal is confronted with the unexpected (variable situations). The flexible behaviour of non-aggressive individuals, depending strongly upon external stimuli, will be of advantage under changing conditions.Studies on wild house mice living under natural conditions show how active and passive coping functions in nature, and how the two types have been brought about by natural selection.     

Control of the cardiovascular system ofAplysia by identified neurons

The neural network that controls the cardiovascular system ofAplysia adapts cardiovascular function to a variety of different physiological and behavioral situations. It (1) coordinates the cardiovascular system with the renal and respiratory systems; (2) modifies both systemic and regional blood flow during food-elicited arousal and feeding; and (3) changes the tension of longitudinal vascular muscle to adapt the arterial tree to changes in body shape. Indirect evidence suggests that the cardiovascular control circuit may also play a role in maintaining homeostasis during egg laying. Several putative neurotransmitters, including acetylcholine, serotonin, R151 and R152 peptides, have been localized to identified neurons in this circuit.