Browsing by Author "VALDES, G"
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- ItemDECREASED KALLIKREIN EXCRETION IN RENAL-TRANSPLANT TREATED WITH CYCLOSPORINE-A(APPLETON & LANGE, 1990) MARTINEZ, L; VIO, CP; VALDES, G; KYCHENTHAL, W; MENDOZA, S
- ItemEFFECTS OF NIFEDIPINE DURING LOW, NORMAL AND HIGH INTAKES OF SODIUM IN PATIENTS WITH ESSENTIAL-HYPERTENSION(1982) VALDES, G; SOTO, ME; CROXATTO, HR; BELLOLIO, T; CORBALAN, R; CASANEGRA, P
- ItemMATERNAL PLASMA-VOLUME EXPANSION AND HORMONAL CHANGES IN WOMEN WITH IDIOPATHIC FETAL GROWTH-RETARDATION(LIPPINCOTT WILLIAMS & WILKINS, 1993) SALAS, SP; ROSSO, P; ESPINOZA, R; ROBERT, JA; VALDES, G; DONOSO, EObjective: To explore the mechanisms underlying the reduced maternal plasma volume associated with idiopathic fetal growth retardation (FGR).
- ItemMINOXIDIL IN THE MANAGEMENT OF MODERATE HYPERTENSION(1980) NICHOLSON, GD; ALLEYNE, GAO; VALDES, G; WESTERMAN, RL
- ItemPLACENTAL ALTERATIONS AND INTRAUTERINE GROWTH-RETARDATION ASSOCIATED WITH ENALAPRIL EXPOSURE IN EARLY, MID, AND LATE PREGNANCY IN THE RAT(1993) VALDES, G; CHUAQUI, R; CORTHORN, J; DUARTE, IObjective: To identify the stage of placental development in which enalapril use in the pregnant rat is deleterious.
- ItemPLACENTAL ALTERATIONS, INTRAUTERINE GROWTH-RETARDATION AND TERATOGENICITY ASSOCIATED WITH ENALAPRIL USE IN PREGNANT RATS(1992) VALDES, G; MARINOVIC, D; FALCON, C; CHUAQUI, R; DUARTE, IEnalapril (15 mg/kg/day p.o.) was given to 11 pregnant rats from day 1 to 9 (E1-9) and to 11 rats from day 10 to 20 (E10-20) of pregnancy; 12 rats were the control group. Fifteen animals were sacrificed on day 20 of pregnancy and 19 were allowed to progress into partum. Placentas were smaller in E10-20 rats (-15%, p < 0.05) and had a simple hypocellular cordonal structure; in E1-9 animals the predominant pattern was a combination of complex and simple structure. At day 20 the fetuses in the treated groups were smaller than the controls (-5% in E1-9 and -16% in E10-20, p < 0.05); differences disappeared on the 13th day postpartum. Two fetuses from treated mothers presented incomplete skull ossification. We believe this report adds arguments to preclude converting enzyme inhibitors in pregnancy.
- ItemPOTASSIUM SUPPLEMENTATION LOWERS BLOOD-PRESSURE AND INCREASES URINARY KALLIKREIN IN ESSENTIAL HYPERTENSIVES(1991) VALDES, G; VIO, CP; MONTERO, J; AVENDANO, RIn order to eludicate possible mechanism(s) involved in the blood pressure reduction induced by potassium (K) supplementation, we studied the changes of BP and of some of its regulatory systems, including levels of urinary kallikrein (UKal)-an index of renal kallikrein production. Twenty-four untreated essential hypertensives, with a basal BP of 147/96 +/- 13/7 mmHg and normal renal function, received in crossover, double-blind, randomised fashion, 64 mmol KCl or placebo during two periods of 4 weeks each. At the 4th week of potassium supplementation systolic, diastolic and mean BPs decreased by 6.3 +/- 2 (P < 0.01), 3.0 +/- 2 and 4.1 +/- 2 (P < 0.05) mmHg respectively for the supine position, and 5.0 +/- 2, 4.0 +/- 2 (P < 0.05) and 4.0 +/- 1 (P < 0.05) mmHg for the standing position. Urinary potassium (K) increased from 55 +/- 4 to 123 +/- 6 mmol/24 hours (P < 0.001) and UKal from 692 +/- 69 to 1052 +/- 141 mU/24 hours (P < 0.01). Serum K rose from 3.8 +/- 0.1 mEq/l to 4.1 +/- 0.1 mmol/l (P < 0.001) and PRA from 0.77 +/- 0.12 to 0.99 +/- 0.14 ng/ml/h (P < 0.05). Correlations were observed between UKal and urinary K (r = 0.44, P < 0.0001); between differences in UKal and urinary K and in UKal and urinary Na (r = 0.50, P < 0.0005 and r = 0.48, P < 0.001 respectively). Responders to KCl supplementation (n = 7) had a greater increase of urinary kallikrein (P < 0.005) and PRA (P < 0.05) than nonresponders (n = 8). The present study confirms the mild BP lowering effect and stimulation of UKal by KCl supplementation and shows that variations in UKal correlate with urinary K and characterise patients with potassium sensitivity. Further studies, that include determinations of the circulating components of the kallikrein-kinin system, are required to elucidate whether bradykinin, the enzymatic product of kallikrein and potent stimulator of endothelial protective factors, may be a mediator of the vascular effects described for a high K intake.
- ItemRENIN-SECRETING TUMOR - CASE-REPORT(1980) VALDES, G; LOPEZ, JM; MARTINEZ, P; ROSENBERG, H; BARRIGA, P; RODRIGUEZ, JA; OTIPKA, NRenin-secreting tumor, though rare, should be considered in assessing severe hyperreninemic, hypertensive patients. An 18-yr-old girl with hypokalemic hyperreninemic hyperaldosteronism was studied. No angiographic lesion was detected. The plasma renin activity (PRA) of the right/left renal vein was 7.3. With a presumptive diagnosis of renin-secreting tumor (RST), the patient was operated on, and a cortical nodule was found on the right lower pole. Partial nephrectomy was followed by a rapid fall in PRA (half-life, 33-44 min) and normalization of blood pressure (BP). At 3 1/2 mo. postoperatively, the patient showed normotension, normopokalemia, normal aldosterone and slightly elevated PRA unresponsive to postural changes and furosemide treatment. Tumoral PRA secretion responded to postural stimulus, spironolactone use and nitroprusside-induced hypotension. Neither the high aldosterone excretion nor hyperreninemia decreased after 3 days of DOCA [deoxycorticosterone acetate]; this agrees with a previously reported case, suggesting the usefulness of this test in the diagnosis of RST.
- ItemTHE NEUROGENIC RESPONSE TO 55-DEGREE HEAD-UP TILT IN NORMAL PREGNANT-WOMEN(1986) VALDES, G; SALAS, SP; FORADORI, AC; GORMAZ, G; CROXATTO, HR
- ItemURINARY KALLIKREIN ACTIVITY DURING RAT PREGNANCY(1987) SALAS, SP; ROBLERO, JS; CROXATTO, HR; VALDES, GChanges in urinary kallikrein activity and its possible correlation with changes in blood pressure and renal excretory function during pregnancy were studied in the rat. To establish a possible physiological role of kallikrein in this condition aprotinin, which inhibits kallikrein as well as other serine protease was administered to pregnant rats. Urinary kallikrein activity was markedly increased during pregnancy and correlated positively with urine volume and electrolytes excretion, but not with blood pressure. Aprotinin administration almost completely inhibited kallikrein activity, however, blood pressure levels, urine volume and electrolytes were not changed after one day of aprotinin treatment. In conclusion, although renal kallikrein is highly enhanced during pregnancy, its physiologic role in this condition remains elusive.
- ItemURINARY KALLIKREIN AND PLASMA-RENIN ACTIVITY IN NORMAL HUMAN-PREGNANCY(1981) VALDES, G; ESPINOZA, P; MOORE, R; CROXATTO, HR
- ItemUTERINE KALLIKREIN IN THE EARLY PREGNANT RAT(OXFORD UNIV PRESS INC, 1993) VALDES, G; CORTHORN, J; SCICLI, AG; GAETE, V; SOTO, J; ORTIZ, ME; FORADORI, A; SAED, GMUterine homogenates of cycling and early pregnant Sprague Dawley rats and purified rat urinary kallikrein showed similar curves of displacement of I-125-kallikrein binding to a polyclonal antibody. Uterine kallikrein concentration measured by RIA was 8.7 +/- 2 SEM ng/g wet weight during the cycle (n = 6 in diestrus and metestrus) and 20.8 +/- 2 SEM (n = 7) ng/g wet weight on Day 7 of pregnancy (P7) (p < 0.001). On P7, kallikrein concentration was increased 12.4-fold in the implantation nodes, as compared to the interimplantation segments. Uterine homogenates of rats on P7, submitted to DEAE-cellulose chromatography and Sephadex gel filtration, yielded two fractions containing kallikrein immunoreactivity and kininogenase activity, with molecular masses that ranged from 120-125 kDa and 39-43 kDa, respectively. In the RIA, both fractions displayed parallelism with purified kallikrein. Enzymatic activity was expressed after activation by trypsin. It was inhibited by aprotinin, PMSF, p-amino-benzamidine, and leupeptin, but not by soybean or ovomucoid trypsin inhibitors. Kallikrein mRNA was demonstrated by reverse transcriptase/polymerase chain reaction in uteri of nonpregnant and P7 rats. These results show that rat uterus synthesizes one or more serine proteases that are immunologically and enzymatically related to tissue kallikrein. The increase of kallikrein in the implantation node on P7-determined both by an increment of whole uterus kallikrein content and a depletion of the interimplantation segments-suggests that kallikrein may play a role in the vasoactive changes of implantation.
- ItemVARIATIONS IN UTERINE KALLIKREIN DURING CYCLE AND EARLY-PREGNANCY IN THE RAT(OXFORD UNIV PRESS INC, 1994) CORTHORN, J; VALDES, GWe have previously demonstrated the presence of tissue kallikrein and its mRNA in rat uterus, and an increase of the immunoreactive enzyme on Day 7 of gestation, which suggests a hormonal regulation and a role in implantation. This study pursued the sequential variations during the cycle and early pregnancy. During the estrous cycle, immunoreactive uterine kallikrein levels showed a recurrent pattern, with the highest value on proestrus (12.9 +/- 1.5 ng/uterus or 0.49 +/- 0.03 ng/mg protein), and the lowest on metestrus (4.1 ng +/- 0.5 ng or 0.30 +/- 0.03 ng/mg protein); p < 0.05. During gestation, values on Day 1 (6.1 +/- 0.4 ng/uterus or 0.30 +/- 0.01 ng/mg protein) and Day 3 (4.9 +/- 0.3 ng or 0.35 +/- 0.01 ng/mg protein) were similar to levels during estrus and diestrus; a progressive rise, observed from Day 5 (8.2 +/- 1.1 ng or 0.43 +/- 0.02 ngl mg protein), attained the highest value on Day 7 (15.8 +/- 1.7 ng or 0.78 +/- 0.05 ng/mg protein); p < 0.05. The variations observed during the cycle and early gestation coincide with those described for ovarian steroids and uterine vasoactive changes, suggest the hormonal regulation of uterine kallikrein levels, and support its role in implantation.