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Biomedical subjects

E Poch

Publications and source records attributed to E Poch.

At least 55 records · Page 3Linked to original sources
PubMed1994

Effect of antihypertensive treatment on intracellular calcium concentration and intracellular pH in essential hypertension.

The platelet intracellular calcium concentration ([Ca2+]i) and intracellular pH (pHi) were measured by spectrofluorimetry with the dyes Fura-2 and BCECF, respectively, in 19 patients with essential hypertension (10 males), aged 48 +/- 2 years, before and after 12 weeks of antihypertensive treatment and in 19 normotensive controls (11 males), aged 46 +/- 3 years. [Ca2+]i and pHi were measured in the resting state and after stimulation in vitro with 0.1 U/ml human thrombin. In patients with essential hypertension, both resting [Ca2+]i (61 +/- 4 nmol/l) and thrombin-induced maximal increase in [Ca2]i (291 +/- 26 nmol/l) were significantly (P < 0.01) greater than in the normotensive controls (resting 49 +/- 2 nmol/l and thrombin-induced 199 +/- 21 nmol/l). With respect to pHi, no difference in resting pHi between both groups was found (7.16 +/- 0.01 vs. 7.16 +/- 0.01). However, pHi increment at 300 seconds in response to thrombin was higher in the patients with essential hypertension than in the controls (0.131 +/- 0.02 vs. 0.083 +/- 0.01 pH units, P < 0.05). The increment in pHi was blunted by the amiloride derivative EIPA, indicating that it was mediated by the Na+/H+ exchanger. After antihypertensive therapy in the essential hypertensive patients, basal [Ca2+]i was significantly reduced (52 +/- 2 nmol/l, P < 0.01) and was not statistically different to the value found in the normotensive controls. Resting pHi suffered no significant modification after treatment (7.17 +/- 0.01, P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Intracellular calcium mobilization and activation of the Na+/H+ exchanger in platelets.

The aim of the present study was to evaluate the regulatory relationship between the cytosolic free calcium concentration ([Ca2+]i and cytosolic pH (pHi). [Ca2+]i and pHi were measured using the fluorescent dyes fura-2 and BCECF [2',7'-bis-(carboxyethyl)-5,6-carboxyfluorescein] respectively. In a medium with 1 mmol/l extracellular calcium, thrombin (2.5 units/ml) induced an increment in [Ca2+]i of 638 +/- 31 nmol/l (n = 5) and an intracellular alkalinization of 0.14 +/- 0.01 pH units (n = 8). Both responses were dependent on the concentration of thrombin, displaying a sigmoidal dose-response pattern. The intracellular alkalinization was dependent upon extracellular Na+ and was amiloride-sensitive, indicating that it was mediated by activation of the Na+/H+ exchanger. When extracellular calcium was chelated with EGTA prior to the addition of thrombin, the intracellular alkalinization was not affected (0.15 +/- 0.02 at 2.5 units/ml thrombin, n = 8). Under these circumstances, the [Ca2+]i increment represents mobilization from internal stores, reaching 157 +/- 42 nmol/l at 2.5 units/ml thrombin. When platelets were preloaded with the intracellular calcium chelator MAPTAM (1,2-bis-5-methylaminophenoxylethane-NNN'-tetraacetoxymethyl acetate) to block the increase in [Ca2+]i induced by thrombin, no increment in pHi was observed. Moreover, MAPTAM-loaded calcium-depleted platelets had a basal pHi that was more acidic than in the presence of 1 mmol/l extracellular calcium (6.93 +/- 0.09 versus 7.14 +/- 0.01, n = 26, P < 0.001). Ionomycin induced an elevation of [Ca2+]i that was accompanied by a concomitant increase in pHi, which was Na(+)-dependent and amiloride-sensitive. [Ca2+]i and pHi increases induced by ionomycin were both dependent on the concentration of ionomycin. In conclusion, an increase in [Ca2+]i is necessary for the agonist-induced activation of the Na+/H+ exchanger in platelets. Non-agonist-induced increases in [Ca2+]i seems to prompt activation of the exchanger. In addition, Ca(2+)-depleted platelets have a more acidic basal pHi, indicating that the basal level of [Ca2+]i is also important for maintaining the basal pHi.

Blood Platelets↗
PubMed1993

Coincidental amyloid nephropathy and IgA glomerulonephritis in a patient with ankylosing spondylitis.

A 43-year-old man with ankylosing spondylitis (AS) was admitted with proteinuria and renal insufficiency. Coincidental IgA nephropathy and secondary renal amyloidosis were diagnosed on renal biopsy. This is the first case reported of coincidental IgA nephropathy and renal amyloidosis as a cause of renal insufficiency in a patient with AS. Both entities should be considered in the diagnosis in a patient with AS and renal impairment. A careful study of the renal tissue including, Congo red stain and immunofluorescence studies is necessary to establish a correct diagnosis in these patients.

Adult↗
PubMed1993

Cytomegalovirus colitis in chronic renal failure.

Cytomegalovirus (CMV) is an ubiquitous agent and is recognized as a pathogen in all age groups. Although symptomatic infection by CMV (CMV disease) in normal adults is generally mild, the virus is known to produce severe symptoms, mostly in immunocompromised patients. In this group of patients, the primary involvement of the colon by CMV is reported to be rare. However, chronic renal failure patients are prone to CMV infection. Nevertheless, despite the high incidence of infection in these patients and the recognition of a defective immune response in some of them, clinical manifestations are an exception. Two chronic renal failure patients who developed acute colitis due to CMV infection are presented. Of interest are the rarity of the association, the favorable clinical course and the differential diagnosis with other gastrointestinal disorders which are more common in these patients.

Aged↗
PubMed1992

Calciphylaxis in a hemodialysis patient: appearance after parathyroidectomy during a psoriatic flare.

Chronic renal failure patients are prone to soft tissue calcifications. A phenomenon of acute ischemic skin necrosis and dermohypodermic arteriolar medial calcification has been described recently in patients with chronic renal failure and secondary hyperparathyroidism (HPT). This phenomenon, termed calciphylaxis, occurs in response to certain factors, the most important of which appears to be an elevated blood calcium-phosphate product. Accordingly, parathyroidectomy in addition to normalization of calcium-phosphate product has been proposed as the only effective therapeutic approach for this condition. We describe a case of chronic renal failure with severe secondary HPT in which the patient developed calciphylaxis 4 days after the appearance of a psoriatic flare. Four months before, a subtotal parathyroidectomy was performed for severe HPT and at the time the ulcerations appeared, blood calcium-phosphate product was correct. Etiological and physiopathological aspects of calciphylaxis are discussed.

Calciphylaxis↗
PubMed1991

[Late recurrence in pheochromocytoma: need for a long term follow up].

Pheochromocytoma is a catecholamine secreting tumor which has been traditionally considered as a potentially curable cause of hypertension. However, the existence of malignant pheochromocytomas as well as the problem which the recurrence of benign pheochromocytomas present, make the eradication of this tumor more complicated. It is note worthy the difficulty in localizing recurrent pheochromocytomas as well as the prognostic interest that presents the possibility of differentiating between recurrence and metastasis. We refer the case of a female patient suffering benign adrenal pheochromocytoma, who, 10 years it was surgically removed, presented a relapse of symptoms, and was diagnosed of extra-adrenal pheochromocytoma, in Zuckerkandl organ. The importance of performing a long term post-surgical follow-up in these patients is stressed.

Adrenal Gland Neoplasms↗
PubMed1990

[Lymphocyte beta 2-adrenergic receptors in pheochromocytoma].

To assess the effect of chronic exposure to high circulating catecholamine concentrations on the beta 2-adrenergic receptors, the density and affinity of lymphocyte beta 2-adrenergic receptors were measured in 5 patients with pheochromocytoma (2 males and 3 females, with a mean age of 39 +/- 12 years). In 4 patients the studies were repeated 15 days after tumor removal. Before surgery, all patients had high plasma catecholamine concentration. The density of beta 2-adrenergic receptors was reduced, although their affinity was within the reference range. There was an inverse correlation between plasma epinephrine concentration and beta 2-adrenergic receptor density (r = -0.959, p = 0.01). After surgical resection, plasma catecholamine concentrations and receptor density became normal. The dissociation constant decreased in the four patients. In conclusion, in the presence of chronically high levels of circulating catecholamines the density of lymphocyte beta 2-adrenergic receptors is reduced. However, it becomes normal when plasma catecholamine concentration returns to the reference values, the dynamic character of this regulation being thus shown. The measurement of these receptors in the lymphocyte could be useful for the diagnosis and follow up of patients with pheochromocytoma.

Adrenal Gland Neoplasms↗
PubMed1990

Silent renal microangiography after mitomycin C therapy.

Mitomycin C (MMC) is an alkylating agent which has been associated with microangiopathic hemolytic anemia and acute renal failure, with an overall incidence between 2 and 10%. This complication can develop several months after the initiation of chemotherapy. Isolated renal impairment without overt microangiopathic hemolytic anemia, although reported, is less frequently documented. We describe a 63-year-old man who developed progressive renal failure without any evidence of hemolysis or thrombopenia 10 months after beginning chemotherapy with MMC and Ftorafur. A renal biopsy displayed features of microangiopathy. The patient required the institution of chronic hemodialysis. In conclusion, it is important to be aware of this indolent but severe renal complication in patients treated with MMC. Urinary parameters and renal function should be monitored over a long period for an early diagnosis.

Adenocarcinoma↗
PubMed1989

[Thrombosis of the superior vena cava as an early manifestation of Behçet's disease. Presentation of 2 cases].

The vascular involvement of Behçet's disease is nowadays considered as an important sign of the clinical evolution of these patients. It can affect both the arterial and the venous territories. Superficial thrombophlebitis is the most common vascular manifestation. Thrombosis of deep veins is relatively rare and it generally appears within the inferior vena cava territory as a late manifestation in the evolution of the disease. We describe two cases of Behçet's disease which presented, at an early stage, thrombosis of the superior vena cava as the more relevant manifestation of the disease. The evolution of both patients was satisfactory with the combination of cyclophosphamide and colchicine. The etiopathogenesis of this manifestation and its therapeutic possibilities are discussed.

Adolescent↗
PubMedDate not supplied

Prosthetic valve endocarditis caused by Corynebacterium pilosum.

A case of prosthetic valve endocarditis caused by Corynebacterium pilosum in a 79-year-old woman developed eighty years after aortic valve replacement with bovine pericardium bioprosthesis is described. In spite of the antibiotic therapy she presented an unfavourable course that led to her death.

Aged↗
PubMedDate not supplied

Pulmonary hemorrhage as a clinical manifestation of hemolytic-uremic syndrome associated with mitomycin C therapy.

Mitomycin C (MMC) is an alkylating agent that has been recently associated with the hemolytic-uremic syndrome (HUS). Pulmonary impairment in the HUS is rarely reported in the literature, and no reports of pulmonary hemorrhage, as a clinical feature of the HUS, have been documented. We describe two women who developed HUS after MMC therapy and presented massive pulmonary bleeding. Pulmonary hemorrhage is an uncommon feature in the HUS, and seems to appear especially in the HUS associated with MMC therapy. It is extremely resistant to standard treatment, and confers a poor prognosis for this disease.

Adenocarcinoma↗
PubMedDate not supplied

[Absence of an association between the C825T polymorphism of the G-protein beta 3 subunit and salt-sensitivity in essential arterial hypertension].

The genetic functional variant C for T in position 825 of the gene encoding G protein beta 3 subunit, GNB3, has been associated with enhanced G protein activation, cell growth and proliferation. This phenotype is associated with enhanced G protein activation and Na(+)-H+ exchanger activity in cells from hypertensive patients. Salt sensitivity affects approximately 50% of hypertensive patients and constitutes an intermediate phenotype determined in part by genetic factors. An association between enhanced Na(+)-H+ exchanger activity and salt sensitivity has been previously reported. The aim of the present study was to investigate the possible association between the G protein polymorphism and salt sensitivity in patients with essential hypertension. A total of 46 patients were studied and classified according to their blood pressure response to a change in sodium intake from low (20 mmol/day) to high (260 mmol/day) into salt sensitive (SS) (n = 20) and salt resistant (SR) (n = 26). GNB3 polymorphism was determined by PCR of genomic DNA and restriction digestion with BseDI. The genotypes distribution among the SS hypertensives was: 8 CC and 12 CT + TT, whereas in SR was: 10 CC and 16 CT + TT (p = 0,577). 24 h mean blood pressure response to salt in the whole group was not different among the different genotypes: CC 4.1 +/- 5.4 mmHg compared to CT + TT 2.9 +/- 6.3 mmHg (p = 0.51). There were no significant differences in the salt induced changes in plasma renin activity, aldosterone, ANP or noradrenaline among the different genotypes. These results indicate that the GNB3 C825T polymorphism has no major influence on the pressor response to salt in essential hypertension and therefore do not support its usefulness as an early genetic marker of salt sensitivity in this disease.

Adult↗