PubMed Health⌕ Search

Biomedical subjects

C Plaza

Publications and source records attributed to C Plaza.

At least 19 recordsLinked to original sources
PubMed2005

Copper(II) complexation by humic and fulvic acids from pig slurry and amended and non-amended soils.

The effect of the consecutive annual additions of pig slurry at rates of 0 (control), 90 and 150 m3 ha(-1) y(-1) over a 4-year period on the binding affinity for Cu(II) of soil humic acids (HAs) and fulvic acids (FAs) was investigated in a field plot experiment under semiarid conditions. A ligand potentiometric titration method and a single site model were used for determining the Cu(II) complexing capacities and the stability constants of Cu(II) complexes of HAs and FAs isolated from pig slurry and control and amended soils. The HAs complexing capacities and stability constants were larger than those of the corresponding FA fractions. With respect to the control soil HA, pig-slurry HA was characterized by a much smaller binding capacity and stability constant. Amendment with pig slurry decreased the binding affinity of soil HAs. Similar to the corresponding HAs, the binding affinity of pig-slurry FA was much smaller while that of amended-soil FAs were slightly smaller when compared to the control soil FA. The latter effect was, however, more evident with increasing the amount of pig slurry applied to soil per year and the number of years of pig slurry application.

Animals↗
PubMed2005

[Valsartan in patients with arterial hypertension and type 2 diabetes mellitus. The lapaval study].

UNLABELLED: Arterial hypertension and diabetes mellitus give rise to a situation of high cardiovascular risk. The potential renoprotection from inhibition of the renin-angiotensin system is a valid option in this type of patient. OBJECTIVE: Evaluate the effect of valsartan on blood pressure (BP) and renal function in albuminuric patients with type 2 diabetes and arterial hypertension. PATIENTS AND METHODS: This was a prospective, observational study. Seventy-four diabetic patients with a blood pressure of > or = 140/90 mmHg, with micro or macroalbuminuria and a) blood creatinine levels lower 1.5 mg/dl (group 1) or b) blood creatinine levels between 1.5 and 2 mg/dl (group 2), were studied and followed up for a 12-week period. Treatment was started with valsartan 80 mg/d, increasing to 160 mg/d, adding torasemide at a dose of 5 mg/d if the target blood pressure of 130/85 mmHg has not been achieved. The degree of BP reduction was analyzed comparatively using a mercury sphygmomanometer and a semi-automatic monitor, the Omron HEM 705 CP. RESULTS: All patients showed a significant reduction of the systolic (SBP) and diastolic (DBP) blood pressures (p< 0.001) over the study period, decreasing from 150.7 +/- 12.8 to 130.8 +/- 9.6 and from 94.7 +/- 7.7 to 76.8 +/- 6.3 mmHg, respectively. A significant reduction was observed only for diastolic blood pressure (101.4 +/- 8.8 to 79.4 +/- 5.6; p < 0.001) in the group 2 of patients. Lowest BP values were always obtained with the semiautomatic device. At the end of the study, 9.5% maintained valsartan 80 mg/d and 36.5% reqcuired the addition of a second or third drug to valsartan 160 mg in order to achieve the therapeutic target BP A significant reduction was observed in the microalbuminuria (75.5 +/- 9.5 to 54.7 +/- 7.3 microg/min; p < 0.001) and macroalbuminuria (n = 20; 0.93 +/- 0.4 to 0.68 +/- 0.4 g/day; p < 0.001). CONCLUSION: Valsartan significantly reduced SBP and DBP Valsartan at 160 mg/d had a significantly greater effect in reducing micro and macroalbuminuria. No changes were observed in renal function, HbA1c or serum potassium. The rate of adverse events was very low.

Adult↗
PubMed2000

Endovascular repair of abdominal aortic aneurysm in a renal transplant patient.

A 65-year-old man presented with an asymptomatic infrarenal abdominal aortic aneurysm of 6 cm in transverse diameter. Five years before he received a cadaveric renal transplant. The patient also had the following risk factors and associated diseases: arterial hypertension, coronary artery disease, previous myocardial infarction, coronary angioplasty and stent, ileal resection secondary to Chron disease, hepatopathy, hyperlipidemia and hepato-renal cystic disease. The ASA classification was III, IV. Considering previous abdominal operations and risk factors, we decided to repair the aneurysm with a minimal aggression. The aneurysm was successfully approached by an endovascular route implanting a 22x10 bifurcated aorto-iliac endovascular prosthesis. The patient died 13 months later after being diagnosed of enterocolitis by cytomegalovirus complicated with sepsis and lung infection. We consider this less invasive modality of treatment a valid and useful alternative in this high-risk group of patients.

Aged↗
PubMed1997

Effects of the novel multiple-action agent carvedilol on severe nephrosclerosis in renal ablated rats.

Antihypertensive drugs have differing effects on renal hemodynamics and morphology. We analyzed whether the use of a new beta adrenoceptor antagonist and vasodilator, carvedilol (CVD), slows the progression of nephrosclerosis and whether the renoprotective effect as well as reduction in cardiac hypertrophy is dependent on the degree of blood pressure reduction. Fifty-four adult male Sprague-Dawley rats were distributed among five groups: group I served as untreated controls with 5/6 nephrectomy (Nx); group II, sham (no renal ablation or drug treatment); group III, CVD 5 (5/6 Nx and treatment with oral CVD at 5 mg/kg/day); group IV, CVD 10 (5/6 Nx and treatment with oral CVD at 10 mg/kg/day); and group V, CVD 20 (5/6 Nx and treatment with oral CVD at 20 mg/kg/day). Tail-cuff blood pressure and 24-hr urine samples were obtained before and at 3, 5 and 11 weeks of treatment with CVD. At the end of the study period, blood was taken to measure serum creatinine, plasma renin activity and CVD levels, as well as the remnant kidney and heart for morphological studies. There was a significant reduction in 24-hr U(ProtV) in all the CVD-treated groups, and it was increasingly evident with the highest dose used. However, only rats receiving doses of 10 and 20 mg/kg/day of CVD exhibited significant decreases in blood pressure. Elevated serum creatinine levels seen in untreated controls were significantly decreased by CVD in treated rats (P < .01), indicating that glomerular filtration rate was improved by this drug. This was associated with a significant increase in U(NaV). Concomitant and significant (P < .01) decreases in plasma renin activity were observed in sham and CVD-treated rats. CVD-treated animals had considerably reduced renal damage (P < .01) and cardiac hypertrophy (P < .01) compared with untreated controls. These data indicate that CVD is effective in delaying progression of renal damage and provides beneficial effects in the remnant kidney and cardiac hypertrophy, even at nonhypotensive doses.

Adrenergic beta-Antagonists↗
PubMed1996

Nutritional status of CAPD patients at three years.

A nutritional assessment was carried out in 63 patients starting treatment from April 1990 up to December 1993. Anthropometric measurements were performed showing a prevalence of protein-calorie malnutrition (PCM) of 21% in a total of 142 clinical surveys carried out in the above-mentioned sample. A steady state of albumin levels in plasma was verified during a three-year follow-up period at a lower level than that of the control group. The patients' lymphocytic profile throughout the study was characterized by lymphopenia and decreased B and T8 lymphocytes. During the first two years of continuous ambulatory peritoneal dialysis (CAPD), a high percentage of patients met the "adequacy" dialysis criteria as residual renal function plays an important role as regards treatment.

Adult↗
PubMed1993

Resistance to the antimicrobial agents of bacteria isolated from non-sterile pharmaceuticals.

The in vitro antimicrobial resistance of 391 bacterial strains isolated from 389 samples of oral and topical medicaments was examined. The numbers of strains isolated (and percentage of samples that present them) were: 234 Bacillus (32.1%), 79 Staphylococcus (13.6%), 46 Micrococcus (11.3%), nine Pseudomonas (1.5%), eight Acinetobacter (1.5%), five Enterococcus (1.2%), three Alcaligenes (0.8%), two Escherichia and Enterobacter (0.5%), one each Providencia, Serratia and Streptococcus (0.2%). Gram-positive bacteria were isolated from topical and oral medicaments and Gram-negative rods were detected only in topical medicaments. The 97.4% of Bacillus strains were resistant to lincomycin and B. cereus was resistant to beta-lactam and trimethoprim-sulphamethoxazole. Staphylococcus spp. showed a high percentage of resistant strains to ampicillin (51.8%), tetracycline (40.5%) and trimethoprim-sulphamethoxazole (48.1%). Staphylococcus epidermidis had the highest number of multiresistant strains. The 23.9% of Micrococcus strains were resistant to colistin. Enterococcus and Streptococcus strains showed multiresistance to penicillin G, aminoglycosides and erythromycin. The 61.5% of Gram-negative rod strains showed multiresistance to beta-lactam antibiotics and erythromycin; Pseudomonas spp. were the most resistant.

Bacillus↗
PubMed1992

Effect of recombinant human erythropoietin treatment on hemodynamic parameters in continuous ambulatory peritoneal dialysis and hemodialysis patients.

We studied the hemodynamic changes and the incidence of hypertension after correction of anemia with recombinant human erythropoietin (rhEPO) in 25 hemodialysis (HD) and in 27 continuous ambulatory peritoneal dialysis (CAPD) patients with a mean age of 44.6 years and a mean time on dialysis of 43.6 months. We analyzed basal and final hemoglobin concentrations, time elapsed to reach target hemoglobin, rhEPO dosage, and the following echocardiographic parameters: left ventricular end-systolic and end-diastolic diameters and volumes, posterior wall thickness, interventricular septum, ejection fraction, fractional fiber shortening, cardiac output index, and peripheral vascular resistance index. We did not find any significant difference between HD and CAPD patients in basal and final hemoglobin, concentrations, time elapsed to reach target hemoglobin, dose of rhEPO received for response, and incidence of hypertension. Changes were more evident in HD patients, with a decrease of 15% in cardiac output index and an equal increase of peripheral vascular resistance,. In the patients on CAPD, these variations were less important, with a decrease in cardiac output index of 10% and no significant change in peripheral vascular resistance. Despite both techniques showing the occurrence of hypertension, the left ventricular mass stabilized during the study time. We conclude that CAPD seems to modulate the changes observed in hemodynamic parameters after rhEPO treatment.

Adult↗
PubMed1992

Low turnover bone disease is the more common form of bone disease in CAPD patients.

CAPD is considered a risk factor for low turnover bone disease. This was previously attributed to aluminum accumulation. We evaluated by biochemical and histomorphometric parameters (including double tetracycline labelling), 26 patients maintained on CAPD for 12-14 months. Three (11.5%) showed mild hyperparathyroidism, 5 (19.2%) osteitis fibrosa, 3 (11.5%) mixed forms, 4 (15%) osteomalacia and 11 (42.3%) adynamic bone disease. Only one patient with diabetes mellitus showed an aluminum stained bone surface > 10%. Intact PTH serum levels were lower in LTBD (133.2 +/- 128 vs 468.2 +/- 451 pg/ml; p < 0.05). We also evaluated prospectively 11 patients who underwent a bone biopsy at start of dialysis and after 12 months of CAPD treatment. Bone biopsies pre CAPD demonstrated normal-high bone turnover disease in 8/11 (72.7%) and low turnover bone disease in 3/11 (27%). In the follow-up biopsies, 2 patients showed osteitis fibrosa and other two mild forms. Low turnover bone disease was found in 7 patients (3 osteomalacia and 4 adynamic bone disease). We conclude that the predominant bone lesion in our CAPD patients is low turnover bone disease, predominantly adynamic forms, and aluminum does not seem to play a role on its genesis. Low intact PTH serum levels may be a predictor of low turnover bone disease.

Bone and Bones↗
PubMed1992

Could CAPD modulate the hemodynamic changes induced by rHuEPO treatment?

Hemodynamic response to treatment with erythropoietin has been analyzed on two different groups of patients. The first group of 25 patients was treated with hemodialysis. The second group of 27 was treated with peritoneal dialysis. Both groups were studied before starting the treatment with erythropoietin, after reaching the hemoglobin target point, and after one year of treatment. The following parameters were recorded: basal and hemoglobin target point, time and dosage of response, incidence of arterial hypertension, diastolic and systolic left ventricular diameters, interventricular septum and posterior wall thickness, ejection fraction, fractional fiber shortening, left ventricular mass index, cardiac output index and peripheral resistance index. The incidence of hypertension was 28.8% and, in both techniques, stabilization of left ventricular mass index occurred a year later. When the hemoglobin target point was reached, a decrease in cardiac output and an increase in peripheral resistance was found. These changes were more evident in the group of patients treated with HD. After a year of treatment, both peripheral resistance and cardiac output were similar to basal values in both groups of patients.

Adult↗
PubMed1992

Peritoneal dialysis efficiency in CAPD patients in treatment with rHuEPO.

Possible modifications in peritoneal behaviour that can be caused by erythropoietin (EPO) treatment and/or correction of anemia in the ultrafiltration and peritoneal diffusion were studied in 24 CAPD patients. The evolution of the patients on the medium run was also studied. The dialysate to plasma ratio, the peritoneal clearance and the mass transfer coefficient of urea and creatinine and the ultrafiltration volume were studied, baseline, after reaching the hemoglobin target, and after eight months of treatment. The group of patients developed a decrease in the dialysate to plasma ratio and in the peritoneal clearance of creatinine. After evaluating the effects of the hemoglobin and the hematocrit, we found a decrease in the dialysate to plasma ratio of urea and creatinine, and in the peritoneal clearance of creatinine. A decrease was also found in the mass transfer coefficients of urea and creatinine. An increase in the ultrafiltration was also found in the patients with hemoglobin levels higher or equal to 11 g/dl. Those changes are reversible after turning the hemoglobin levels back to levels lower than 11 g/dl.

Adult↗
PubMed1991

Anemia in dialysis: its relation to acquired cystic kidney disease and serum levels of erythropoietin.

Acquired cystic kidney disease has been related to improvement of anemia in dialysis patients. It has been suggested that this could be due to erythropoietin production by the cysts. We studied 110 patients, 58 on hemodialysis and 52 on continuous ambulatory peritoneal dialysis, with an age of 48.6 +/- 14.78 years and a time on dialysis of 44.5 +/- 35.53 months. A renal echography was performed in every patient, evaluating presence and number of cysts. These findings were related to the blood levels of hemoglobin, ferritin, and erythropoietin as well as to the number of transfusions prescribed during the year of the study. The serum erythropoietin level was 18.23 +/- 12.14 U/l in hemodialysis patients, 15.04 +/- 12.35 in patients on continuous ambulatory peritoneal dialysis, and 12.4 +/- 4.7 U/l in the control group. Hemoglobin and erythropoietin were significantly higher in patients with polycystic kidney disease. Patients without cysts had the lowest levels of hemoglobin and erythropoietin, although no significant difference was found in those with multiple bilateral cysts or in those with 1-3 isolated cysts.

Anemia↗
PubMed1989

Percutaneous transluminal angioplasty as best treatment in stenosis of vascular access for hemodialysis.

We show the results of treatment with percutaneous transluminal angioplasty on 38 occasions for vascular access for hemodialysis. Our study includes 22 patients with A-V internal fistulas (Cimino type), 1 autologous saphenous vein shunt and 7 synthetic polytetrafluoro-ethylene shunts. Twenty patients have had a follow-up period over 24 months. Four patients required a second and 2 of them a third transluminal dilatation. Only on two occasions were complications related to the technique. The microscopic findings of the venous wall after percutaneous transluminal angioplasty are shown.

Adult↗
PubMed1988

Diazoxide-induced long-term hyperglycemia. I. Preservation of B-cell insulin-releasing capacity.

Although several models of experimental diabetes mellitus are currently available, none of them appears to be optimally suited to study the possible deleterious effect of sustained hyperglycemia upon biochemical and functional variables in pancreatic islet cells in the absence of chronic stimulation of secretory activity. In the present study, oral diazoxide administration (0.33 g/Kg body wt. thrice per day for three days) to rats was used to cause both hypoinsulinemia and hyperglycemia (greater than or equal to 10.0 mM), the latter persisting, albeit at a somewhat lower level, for at least 1-2 days after cessation of diazoxide treatment. Ten hours after the last administration of diazoxide, the secretory response of isolated islets to D-glucose over 90 min incubation was not impaired. It is proposed that such a model may help to dissociate the influence of hyperglycemia itself upon islet cell behaviour from the consequences of sustained hypersecretion of insulin.

Animals↗