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Biomedical subjects

D Russo

Publications and source records attributed to D Russo.

At least 217 records · Page 12Linked to original sources
PubMed1989

Acute cyclosporine renal dysfunction reversed by dopamine infusion in healthy subjects.

Up to now, no studies have been performed in normal humans to investigate the role of renal hemodynamic abnormalities in relation to acute-cyclosporin A (CsA) renal dysfunction and to verify whether the specific renal vasodilator, dopamine, can counteract these abnormalities. Eight normal subjects were examined both (A) after oral CsA (12 mg/kg body wt) and (B) after oral CsA + dopamine infusion (2 mg/kg body wt/min), under water diuresis. Both in protocols A and in B, four basal renal clearances were performed before CsA and every twenty minutes for four hours after CsA administration. In protocol A, after CsA, inulin (GFR) and PAH clearance (RPF) fell by up to 27% and to 41%, respectively, so that filtration fraction (FF) increased (P less than 0.01). A slight (not significant) hypertension occurred while renal resistances were markedly raised (P less than 0.001). Fractional urine and Na+ excretion as well as CH2O decreased, while UOsm increased (P less than 0.01). In protocol B, dopamine was infused from 120 to 180 minutes after CsA (that is, when the maximal adverse effects of CsA on renal hemodynamics had been observed in A). Dopamine infusion could reverse completely the effects of CsA on RPF, GFR, fractional urine output and CH2O; only UOsm remained higher than normal in conclusion with an increased fractional excretion of sodium (P less than 0.01). No changes were observed in plasma renin activity, aldosterone and in urinary epinephrine and norepinephrine excretion both in protocols.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Dexamethasone therapy selectively increases the sensitivity to noradrenaline of the rat mesenteric circulation.

We studied the effects of dexamethasone on the vascular responsiveness of the isolated perfused mesenteric vascular bed of the rats. Dexamethasone was infused at a low dose (2 micrograms/day) to avoid steroid-induced catabolic effects. The mesenteric arteries were perfused with increasing concentrations of noradrenaline, vasopressin and potassium chloride. Vascular responses to vasopressin and potassium chloride were similar in both dexamethasone-treated and control arteries. However, the dexamethasone treatment increased the sensitivity, but not the maximal pressor response, to noradrenaline. These results show that dexamethasone selectively increases the vascular sensitivity to noradrenaline in rats before the development of systemic hypertension.

Animals↗
PubMed1989

Glomerular dynamics and salt balance in pregnant rats with renal hypertension.

These studies were aimed at investigating whether chronic hypertension in pregnancy causes changes both in salt excretion (NaE) and in glomerular hemodynamics. Metabolic and renal micropuncture studies were performed in pregnant (P) and Virgin (V) Munich-Wistar rats with normal blood pressure (N) and two-kidney Goldblatt hypertension (H). Mean NaE was higher in PN than VN (2.7 vs. 1.7 meq/day, P less than 0.01). Hypertension raised NaE both in P and V rats: in P and V rats with "benign" hypertension (blood pressure less than 180 mmHg) NaE averaged 3.2 and 2.6 meq/day, respectively (P less than 0.05); mean NaE was 5.9 and 3.8 meq/day, respectively (P less than 0.01), in P and V rats with "malignant" hypertension (blood pressure greater than or equal to 180 mmHg). Afferent arteriole resistance (Ra) averaged 1.73 and 3.50 10 dyn.s-1.cm5 in PN and VN, respectively (P less than 0.01). Hypertension raised Ra in V, but not in P rats (4.47 vs. 2.14 10 dyn.s-1.cm5, P less than 0.01). Thus glomerular plasma flow, glomerular capillary hydrostatic pressure, and single-nephron glomerular filtration rate were markedly higher in PH than VH rats: in PH rats single-nephron filtration fraction was significantly lower than in VH. These results show that in PH rats a marked rise in NaE is associated with glomerular vasodilation.

Animals↗
PubMed1989

Effects of uremia, acetate and bicarbonate dialysis on beta-adrenergic responsiveness as assessed by epinephrine-stimulated adenylate cyclase.

This study was designed to evaluate beta-adrenergic responsiveness as assessed by the generation of cyclic AMP after the subcutaneous administration of epinephrine in 31 subjects: normal controls, patients with chronic renal insufficiency, hemodynamically stable patients on chronic acetate dialysis and hemodynamically unstable patients with acetate intolerance on chronic bicarbonate dialysis. As compared with controls, only unstable patients on bicarbonate dialysis presented impaired beta-responsiveness, which, in turn, was acutely reduced only after acetate but not bicarbonate dialysis. Our results show that acetate dialysis impairs the beta-adrenergic responsiveness and that the observed beta-hyporesponsiveness in unstable patients with acetate intolerance may represent part of a broader spectrum of autonomic dysfunction which may develop in some patients on chronic hemodialysis.

Acetates↗
PubMed1989

Thyrotropin regulation of thyroid peroxidase messenger ribonucleic acid levels in cultured rat thyroid cells: evidence for the involvement of a nontranscriptional mechanism.

The influence of TSH on thyroid peroxidase (TPO) gene expression was investigated in FRTL5 rat thyroid cells. Cultured in the presence of TSH, these cells express a TPO mRNA species of 3.1 kilobases. TSH withdrawal from the culture medium led to a decline in TPO mRNA levels over 24 h. In contrast, no decline in beta-actin mRNA levels occurred after 24 h of incubation in TSH-free medium. TSH (1 mU/ml) added to FRTL5 cells cultured in the absence of TSH increased TPO mRNA levels 7- to 9-fold compared to levels in control cells. This effect of TSH on TPO mRNA accumulation in FRTL5 cells was time related (it was already present after 4 h and was maximal after 24 h of cell exposure to TSH), dose related (0.01 and 1 mU/ml were, respectively, the lowest and the maximally effective doses), and independent of new protein synthesis, in that it was not prevented by cycloheximide (100 microM). cAMP analogues [8-bromo-cAMP and (Bu)2cAMP] also increased TPO mRNA levels, although to a lesser degree than TSH. Run-on transcription analysis in nuclei prepared from FRTL5 cells previously cultured in the presence or absence of TSH did not reveal any difference in TPO mRNA transcripts. These results suggest that TSH regulates the level of TPO mRNA in FRTL5 cells, in part via the second messenger cAMP and by a nontranscriptional mechanism. This TSH effect may represent a primary site of TSH action in regulating TPO bioactivity.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1989

Total or partial percutaneous renal ablation in the treatment of renovascular hypertension: radiological and clinical aspects.

In 15 patients with renovascular hypertension, considered unsuitable for angioplasty or surgery, percutaneous renal ablation was performed by injection of ethanol into the renal vasculature. Partial or complete renal ablation was confirmed by follow-up intravenous pyelography or arteriography. Patients were followed-up for a mean of 24.8 months after therapy and blood pressure was improved in all patients with five being cured. This study shows that percutaneous renal ablation is a useful and successful method of therapy for renal hypertension, and that it should be considered in patients unsuitable for surgery or angioplasty.

Adolescent↗
PubMed1988

Facilitatory effect of ventral tegmental area A10 region on the attack behaviour in the cat: possible dopaminergic role in selective attention.

Lateral hypothalamus (LH) stimulation in cats which do not spontaneously attack rats, produces an attack pattern which may be divided into 3 main stages: the first, defined as exploratory time (ET), begins with an environmental search and culminates in orienting towards the prey; in the second, defined as attack time (AT), the cat stalks the rat; the last is the biting stage in which the cat seizes and kills the prey by biting its head and neck. The effects of ventral tegmental area (VTA) stimulation on the latency of the whole sequence and on the different stages of the attack pattern were studied. VTA activation resulted in a significant decrease of biting latency, due to the reduction of exploratory time. Moreover, a significant period of prey fixation, seldom present during LH stimulation alone, was observed after VTA-LH co-stimulation. Sulpiride injection caused the disappearance of VTA effects on the predatory pattern. The results indicate that VTA activation induces a decrease in behaviour related to exploration of the environment, and an increase in the focusing of attention on the prey, which seems an important component in the regulation of the predatory pattern. Pharmacological evidence indicates that the VTA effect is mediated by the mesolimbic-mesocortical dopaminergic (DA) system.

Animals↗
PubMed1988

Sensitivity of Ph 1 + CFU-GM to human recombinant interferon alpha and gamma alone and in combination.

The in vitro effect of human recombinant interferon alpha (IFN) alone and in combination were studied on granulomonocytic colony forming units (CFU-GM) from the peripheral blood of 10 Ph 1+ chronic myeloid leukemia (CML) patients and from the marrow of 5 normal or non-leukemic subjects. alpha- and gamma-IFN alone determined a slight inhibition on colony growth with a preferential effect on "pure" macrophagic colonies. At maximum concentration (10(4) U/ml) leukemic colony inhibition was 46 +/- 34% for alpha IFN and 43 +/- 19% for gamma IFN. Culture growth with alpha + gamma IFN in combination were significantly inhibited (up to 96 +/- 4%) with a concentration-related effect. Similar results were obtained with normal CFU-GM. The synergism that was found in vitro is probably relevant for the in vivo therapeutic effects of these compounds in CML and suggest that the combination is worth testing in vivo.

Drug Therapy, Combination↗
PubMed1988

Effects of furosemide therapy on free-water excretion in uremic patients.

To assess the intrinsic effects of treatment with furosemide on free-water excretion in patients with chronic renal failure, two groups of patients with and without replacement of diuretic-induced salt losses have been studied. Furosemide therapy was administered for 1 week during constant sodium intake (100 mEq/day). In neither of the groups did furosemide cause hyponatremia, while it did decrease the urine to plasma osmolality ratio, an effect lasting even when the diuretic effect was exhausted. During water diuresis, furosemide decreased the fractional sodium reabsorption in diluting segments but not the absolute rate of the free-water generation (CH2O). Presumably the expected decrease of CH2O was masked by the increased distal delivery of tubular fluid mainly due to an additional effect of the diuretic on the proximal tubule. The hypotonicity of urine after furosemide treatment may be secondary to the dissipation of medullary hypertonicity, caused by furosemide, in the condition of decreased water permeability of the collecting duct due to uremic disease.

Furosemide↗
PubMed1988

Treatment of severe renovascular hypertension by percutaneous transluminal renal angioplasty in patients with solitary functioning kidney. Effects on blood pressure and renal function.

In this study the effects of percutaneous transluminal renal angioplasty on blood pressure and renal function were studied in 9 hypertensive patients with stenosis of the main artery of a solitary functioning kidney. The outcome of the percutaneous dilatation of the renal artery stenosis, and the effects on blood pressure and renal function were evaluated for a mean period of 16.4 +/- 2.13 (SE) months (ranging from 3 to 65 months). A successful dilatation of the renal artery stenosis was shown in all the patients by the aortography performed 1 h after the procedure. At the discharge (7.8 +/- 0.9 days after dilatation), blood pressure was 'cured' in 2 patients and 'improved' in the remaining patients; renal function was improved in all patients who had reduced renal function. At the last follow-up, no restenosis was found in patients who repeated the follow-up angiography; blood pressure was 'cured' in 3 patients and 'improved' in 6 patients, and renal function appeared steadly improved. In contrast with other reports, our results demonstrate that percutaneous renal angioplasty is a safe and effective procedure and should be attempted before considering surgical intervention in patients with artery stenosis of a solitary functioning kidney.

Adult↗
PubMed1988

Treatment of massive hemorrhage after renal biopsy with percutaneous arterial obliteration.

Severe perirenal hemorrhage is a major, although rare, postbiopsy complication. We report a case of a 48-year-old man with a postbiopsy massive bleeding from a ramification of the renal artery supplying the lower pole of the left kidney. Treatment consisted of complete obliteration of the bleeding vessel by helding a percutaneous catether in wedge position during a renal arteriographyc study. Our case shows that percutaneous arterial obliteration is a successful procedure in treating postbiopsy renal hemorrhage, representing an effective alternative to surgical therapy.

Biopsy, Needle↗
PubMed1987

Renal handling of urea in subjects with persistent azotemia and normal renal function.

Fourteen subjects with persistent azotemia and normal glomerular filtration rate were studied by renal clearances and hormonal determinations to establish the nephron site of altered urea transport and the mechanism(s) responsible for their azotemia. During constant alimentary protein, urea nitrogen appearance was normal and urea clearance was much lower than in 10 age-matched control subjects (23.3 +/- 2.1 ml/min and 49.6 +/- 2.6 ml/min per 1.73 m2, P less than 0.001). Inulin and para-aminohippurate clearances, blood volume and plasma concentration of antidiuretic hormone were within normal limits. During maximal antidiuresis, in spite of greater urea filtered load, the urinary excretion of urea was less, and both the maximum urinary osmolality and the free-water reabsorption relative to osmolar clearance per unit of GFR were greater than in control subjects. After sustained water diuresis, the plasma urea concentration markedly decreased to near normal levels in azotemic subjects. The basal urinary excretion of prostaglandins E2 was significantly reduced in azotemic subjects and was directly correlated with fractional urea clearance (r = 0.857, P less than 0.001). An additional group of control subjects (N = 8) showed a marked reduction of fractional clearance of urea after inhibition of prostaglandin synthesis (P less than 0.01). These data suggest that azotemia is due to increased tubular reabsorption of urea in the distal part of nephron, presumably because of increased back diffusion in the papillary collecting duct, accounting for the enhanced maximum urinary osmolality and free-water reabsorption. Renal prostaglandin E2 may participate in the pathogenesis of azotemia by altering recycling of urea in the medulla.

6-Ketoprostaglandin F1 alpha↗