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Biomedical subjects

J Calls

Publications and source records attributed to J Calls.

11 recordsLinked to original sources
PubMed2005

Lercanidipine in patients with chronic renal failure: the ZAFRA study.

OBJECTIVE: The objective was primary to evaluate the safe use of a new calcium channel blocker, lercanidipine, in patients with chronic renal failure (CRF). The secondary objective was to study the protective effect of calcium channel blocker on renal function in CRF patients previously treated with ACE inhibitors or angiotensin receptor blockers. DESIGN AND METHODS: The study recruited 203 CRF patients (creatinine >1.4 mg/dL for males, creatinine > 1.2 mg/dL for females, or creatinine clearance <70 mL/min). All patients were receiving ACE inhibitors (63.4%) or angiotensin II antagonist (36.6%) therapy, but they had higher blood pressure than recommended for CRF (130/85 mmHg). No patients were under diuretic treatment. Patients were clinically evaluated 1, 3, and 6 months after starting treatment with lercanidipine. Samples for urine and blood examination were taken during the examination. When needed, a third drug was added to the treatment, excluding diuretics. Creatinine clearance was measured using 24 h urine collection. RESULTS: 175 patients rendered valuable for the study (age 63.9+/-11.9 years, 52.9% males and 47.1% females). Blood pressure (BP) significantly decreased from 162+/-17/93+/-8.3 mmHg to 132+/-12/78+/-6 mmHg. 89.2% of patients showed a significant BP reduction, and 58.1% achieved optimal BP control (<130/85 mmHg). Seven patients (3.4%) showed untoward effects. Not one case of edema was detected, and the prevalence of adverse effects related to vasodilatation was extremely low (three patients, 1.48%). Plasmatic creatinine did not change (1.9+/-0.5 baseline versus 1.9+/-0.6 mg/dL), but creatinine clearance increased at the end visit (41.8+/-16.0 baseline versus 45.8+/-18.0 mL/min, p=0.019). Plasmatic cholesterol also decreased from 221+/-46 to 211+/-35 mg/dL (p=0.001). CONCLUSIONS: Lercanidipine showed a high antihypertensive effect in CRF patients. It has a good tolerability profile and showed an interesting effect on plasmatic lipids. An improvement in renal function, measured through creatine clearance, was detected.

Aged↗
PubMed2004

[Lercanidipine in diabetic patients with renal failure].

OBJECTIVE: To evaluate the safe use of a new calcium channel blocker, lercanidipine, in diabetic chronic renal failure (CRF) patients. DESIGN AND METHODS: The study recruited 42 diabetic CRF patients (creatinine > 1.4 mg/dl for males, creatinine > 1.2 mg/dl for females, or creatinine clearance < 70 ml/min). Mean age was 68.2 +/- 9.1 years. 53.8% were males and 46.2% females. Three patients were type 1 diabetics and 39 ones were type II. All patients were receiving ACE inhibitors (67.4%) or angiotensin II antagonist (32.6%) therapy but they had higher blood pressure than recommended for CRF patients (130/85 mmHg). No patients were under diuretic treatment. Patients were clinically evaluated 1, 3 and 6 months after starting treatment with lercanidipine. Samples for urine and blood examination were taken during the examination. When needed, a third drug was added to treatment, excluding diuretics. Creatinine clearance was measured using 24 h urine collection. RESULTS: BP significantly decrease from 163 +/- 18/90 +/- 8 mmHg to 134 +/- 12/77 +/- 9 mmHg. One half of patients showed significant reduction of blood pressure, 26.7% reached the target blood pressure (< 130/85 mmHg) and 20.0% gets optimal BP control (< 130/85 mmHg). No one patient showed untoward effects. No edema was detected nor adverse effects related to vasodilatation were found. Plasmatic creatinine did not change (1.9 +/- 0.5 baseline vs 1.8 +/- 0.5 mg/dl) and creatinine clearance increased at the end visit (40.1 +/- 14.5 baseline vs 45.4 +/- 18.2 ml/min) but the difference was not significant. Proteinuria was unchanged. CONCLUSIONS: Lercanidipine showed a good antihypertensive effect in diabetics CRF patients. It has a good tolerability profile and showed neutral effect on plasmatic lipids. Neither impairment of renal function nor increment in proteinuria were detected.

Aged↗
PubMed2000

Beta-adrenergic receptor density and function in left ventricular hypertrophy in young essential hypertensives.

A sympathetic overactivity has been reported in the early stages of essential hypertension and has been involved in the pathogenesis of left ventricular hypertrophy (LVH) in essential hypertension. The state of beta2-adrenergic receptors as related to the presence of this complication was investigated in a group of 15 essential hypertensive patients and compared to 10 normotensive control subjects. Left ventricular mass index was determined by bidimensional echocardiography. Plasma catecholamine levels were measured by a radioenzymatic assay. beta2-adrenoceptor density was measured in intact lymphocytes by radioligand binding assay, using the hydrophilic ligand CGP 12177. beta2- adrenoceptor function was assessed by measuring intracellular cAMP levels in isoproterenol-stimulated lymphocytes. Left ventricular mass index (P < 0.05), body mass index (P < 0.01), plasma noradrenaline levels (P < 0.05) and beta2-adrenoceptor density (P < 0.05) were higher in hypertensives than in controls. Left ventricular mass index correlated with body mass index both in normotensives and hypertensives, as well as with plasma noradrenaline levels only in normotensives. Left ventricular mass index also showed a positive correlation with mean arterial pressure and an inverse relationship with beta2-adrenoceptor density and response only in hypertensive patients. In conclusion, left ventricular hypertrophy in young essential hypertensives is associated to a reduced beta2-adrenoceptor density and function, probably as a compensating mechanism of the hypertrophied myocardiocyte secondary to the increased sympathetic outflow. Journal of Human Hypertension (2000) 14, 17-21.

Adrenergic beta-Agonists↗
PubMed2000

Abnormal platelet cytoskeletal assembly in hemodialyzed patients results in deficient tyrosine phosphorylation signaling.

BACKGROUND: Uremic patients have a bleeding tendency associated with a platelet dysfunction. We evaluated the impact of a repeated hemodialysis procedure on primary hemostasis by analyzing different aspects of platelet activation in uremic patients. METHODS: Studies were performed in (1) eight patients with end-stage renal disease before the hemodialysis program was initiated and after initiating hemodialysis treatment, and in (2) eight patients on maintenance hemodialysis who were transferred to continuous ambulatory peritoneal dialysis. Studies included routine platelet aggregations and evaluation of platelet-subendothelium interactions under flow conditions. Contractile proteins and tyrosine phosphorylation associated with the cytoskeleton were analyzed, before and after thrombin activation of platelets, by electrophoresis after Triton X-100 extraction. RESULTS: No changes in the clinical parameters analyzed were observed among the different study groups. Aggregation and platelet adhesion only improved when patients were shifted from hemodialysis to continuous ambulatory peritoneal dialysis (P < 0.05 for both percentage of surface covered by platelets and aggregate formation). The association of cytoskeletal proteins in platelets from patients under hemodialysis treatment was statistically decreased with respect to the corresponding values in platelets from patients not subjected to dialysis (P < 0.01 for actin). However, after two months on peritoneal dialysis, these values increased to almost control values (P < 0.001 for actin, vs. hemodialysis). Similarly, translocation of tyrosine-phosphorylated proteins to the cytoskeletal fraction was impaired in platelets from hemodialyzed patients, and it recovered partially after the patients transferred to continuous ambulatory peritoneal dialysis. CONCLUSIONS: Our present data support the concept that repeated platelet stress during hemodialysis has a deleterious effect on the organization of platelet cytoskeleton, which seems to impair the translocation of signal transduction proteins within platelets compromising the platelet function in uremia.

Adult↗
PubMed1999

Evaluation of acquired platelet dysfunctions in uremic and cirrhotic patients using the platelet function analyzer (PFA-100 ): influence of hematocrit elevation.

BACKGROUND AND OBJECTIVE: Patients with end-stage renal disease or advanced cirrhosis develop bleeding disorders characterized by defective interaction of platelets with damaged subendothelium. The anemia associated with both clinical entities has a negative influence on hemostasis. We evaluated alterations of platelet function in patients suffering from end-stage renal disease (n=21) or hepatic cirrhosis (n=20) using standard aggregometric techniques and the recently developed platelet function analyzer (PFA-100 ). The impact of low hematocrit was also analyzed. DESIGN AND METHODS: The hemostatic capacity of platelets was tested in the PFA-100 using citrated blood and standard cartridges containing collagen-ADP (COL-ADP) or collagen-epinephrine (COL-Epi). The hemodynamic influence of hematocrit was also evaluated in blood aliquots in which hematocrit was experimentally increased by adding red blood cells from the same patient. RESULTS: Aggregation studies demonstrated abnormal responses to several agonists in both group of patients. Closure times obtained by the PFA-100 for control blood samples were 87+/-3 sec for COL-ADP and 113+/-5 sec with COL-EPi cartridges. Closure times in uremic and cirrhotic patients with average hematocrits of 0.26 and 0.27 respectively were significantly prolonged (139+/-12 and 125+/-14 sec, respectively with COL-ADP and 194+/-29 and 151+/-15 sec with COL-Epi cartridges). A 5% increase in the hematocrit caused a reduction in the closure time to 111+/-7 sec (COL-ADP) and 143+/-14 sec (COL-Epi) in the uremic group and to 86+/-4 sec (COL-ADP) and 115+/-16 sec (COL-Epi) in the cirrhotic group. Our studies confirm the platelet dysfunction in uremic and cirrhotic patients. INTERPRETATION AND CONCLUSIONS: The PFA-100 device proved to be useful for testing alterations of primary hemostasis in these acquired disorders and was sensitive enough to detect modifications in hemostasis caused by elevations in hematocrit. Conventional aggregometric tests were able to identify the intrinsic platelet abnormality in uremic and cirrhotic conditions, while the PFA-100 seemed more sensitive in detecting the negative influence of the hematocrit reduction.

Adult↗
PubMed1998

Effect of recombinant human erythropoietin treatment on circulating reticulated platelets in uremic patients: association with early improvement in platelet function.

Recombinant human erythropoietin improves platelet function in uremia through the correction of anemia, but this effect can be seen also before the hematocrit rise. We studied 12 hemodialyzed patients (seven men, five women) who received recombinant human erythropoietin (40 IU kg(-1)i.v., three times weekly) and were evaluated before treatment and after three doses; 24 control subjects were used. Platelet aggregation induced by adenosine 5'-diphosphate (ADP), epinephrine, collagen, arachidonic acid, and ristocetin, and reticulated platelets determined by flow cytometry after staining with thiazole orange were measured. Platelet aggregation induced by all the agonists were impaired in uremic patients (P < 0.01), but ADP and ristocetin-induced aggregations improved after treatment (P < 0.01). Hemodialyzed patients had less reticulated platelets than controls (P < 0.01). Reticulated platelets increased after three doses of treatment (P < 0.01). In conclusion, improvement of platelet function at early stages of recombinant human erythropoietin treatment may be attributed to the increase in young platelets detected as reticulated platelets.

Adenosine Diphosphate↗
PubMed1998

Platelet-leukocyte activation during hemodialysis detected with a monoclonal antibody to leukocyte integrin CD11b.

Platelet activation is commonly monitored with a battery of monoclonal antibodies against different platelet epitopes with controversial results. The transient expression of platelet markers and their role mediating interactions with other cells could easily explain these discrepancies. The present study has evaluated whether the analysis of a leukocyte activation antigen (CD11b) could provide more reliable results than detection of platelet activation markers. Cytometric techniques with specific monoclonal antibodies were used to compare the reliability of platelet and leukocyte markers to detect activation. Modifications in the presence of platelet glycoproteins GPIb (CD42b), GPIIIa (CD41) and GPIV (CD36), expression of specific platelet markers (P-selectin (CD62P) and lysosomal protein (CD63)) and leukocyte integrin (CD11b) were assessed during hemodialysis. Platelet antigens remained in uremic patients at levels similar or slightly above those detected in a group of healthy subjects. Modifications of platelet antigens during hemodialysis produced inconclusive results. However, numbers of leukocytes expressing CD11b increased progressively during hemodialysis (17.2 +/- 5.1% at 15 min and 21.3 +/- 6.6% at 2 h, p < 0.05, vs. baseline 6.9 +/- 0.2%). The hemodialysis procedure caused an increased formation of leukocyte-platelet aggregates. Detection of leukocyte CD11b may be a useful marker of overall cellular activation during the hemodialysis procedure.

Aged↗
PubMed1996

Polymorphisms of the human alpha 2A-adrenergic receptor gene in a Catalan population: description of a new polymorphism in the promoter region.

Alpha 2A-adrenergic receptor polymorphisms were investigated in 55 unrelated Caucasian Catalan individuals. Phenotypes were expressed by alpha 2-adrenoreceptor density and affinity determined by radioligand binding. In addition to the two previously described biallelic restriction fragment length polymorphisms (RFLP) (DraI and Bsu36I) [Hoehe et al 1988; Sun et al 1992], a transition was located in the promoter region of the human alpha 2A-adrenergic receptor using a non-radioisotopic single-strand conformational polymorphism (SSCP) analysis. DNA sequence analysis of this region showed that this transition produces the loss of a HhaI site. In our sample, the estimates of the frequency of this allele was 11% and those of DraI alleles were similar to those reported for other Caucasian populations but different from those observed in Afro-Americans. In addition, frequencies of the Bsu36I alleles in the Catalan population differed from those of Japanese and American White populations. A slight linkage disequilibrium between Bsu36I-DraI was found in our population. No association between phenotypes and RFLP genotypes was observed.

Alleles↗
PubMed1995

Effect of antihypertensive treatment on the increased beta 2-adrenoceptor density in patients with essential hypertension.

The effect of different antihypertensive drugs on the increased surface beta 2-adrenoceptor density in essential hypertension was evaluated to elucidate whether the possible effect of the treatment on these receptors was secondary to blood pressure decreases or a specific effect of the drugs. Thirty-nine untreated essential hypertensive patients and 28 normotensive control subjects were studied in basal conditions. Hypertensive patients were randomly assigned to three treatment groups: bisoprolol (10 mg/day, n = 15), enalapril (20 mg/day, n = 12), and verapamil SR (240 mg/day, n = 12), and were studied before and after 1 month of treatment. Plasma catecholamines were determined by a radioenzymatic assay. Surface beta 2-adrenoceptors were measured in intact lymphocytes by radioligand binding assay using the hydrophilic ligand [3H]-CGP12177. beta 2-adrenoceptor density was increased in hypertensive patients (P < .01). After treatment, mean blood pressure decreased similarly in the three groups, while plasma catecholamines showed no significant changes in any group. beta 2-adrenoceptor number decreased only in bisoprolol-treated patients (P < .05). Mean blood pressure decreases correlated with beta 2-adrenoceptor decrements only in bisoprolol-treated patients (r = 0.65, P < .05). beta 2-adrenoceptor density correlated with plasma epinephrine levels in the control group (r = -0.50, P < .01), but not in hypertensive patients before treatment. This correlation was also observed in hypertensive patients treated with bisoprolol (r = -0.52, P < .05), but not in those treated with verapamil or enalapril. Our results suggest that bisoprolol treatment reduces the increased surface beta 2-adrenoceptor density and restores its regulation by epinephrine in essential hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Reversible decrease of surface beta 2-adrenoceptor number and response in lymphocytes of patients with pheochromocytoma.

To study the effect of chronic exposure to elevated plasma catecholamines on surface beta 2-adrenoceptor density, we measured these receptors in the lymphocytes of 9 patients with pheochromocytoma as well as in 27 healthy control subjects. Binding experiments were performed on intact lymphocytes using the hydrophilic ligand [3H]-CGP12177. Lymphocyte beta 2-adrenergic response was also measured in three patients. beta 2-adrenoceptor density (p < 0.01), and isoproterenol-stimulated increase in cAMP were reduced in patients with pheochromocytoma. Both parameters normalized (p < 0.05) when patients were reevaluated 4 weeks after tumor removal, coinciding with normalization of plasma epinephrine (r = -0.95, p < 0.01) and to log of plasma norepinephrine (r = -0.58, p < 0.05) in patients. We conclude that chronic catecholamine excess induces a decrease of lymphocyte beta 2-adrenoceptor surface number and response that is reversible upon normalization of plasma catecholamine levels. This regulation is mainly dependent on plasma levels of the hormone epinephrine, but norepinephrine may also play a regulatory role at supraphysiological levels.

Adrenal Gland Neoplasms↗