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Biomedical subjects

J Díez

Publications and source records attributed to J Díez.

At least 109 records · Page 6Linked to original sources
PubMed1992

[Effects of captopril on left ventricular morphology and function in essential arterial hypertension].

BACKGROUND: The presence of diastolic dysfunction in a hypertensive patient is not necessarily associated to the existence of left ventricular hypertrophy. The aim of this study was to determine whether the reduction of the left ventricular mass in hypertensive patients treated with captopril is accompanied by an improvement of the diastolic filling indexes. METHODS: Nineteen patients with essential hypertension were studied before and after one year of treatment with captopril. Different morphological indexes and diastolic function of the left ventricle were evaluated by mode M and Doppler echography. RESULTS: The indexes of left ventricular mass diminished significantly with treatment with captopril. The thickness of the ventricular walls diminished with treatment although not significantly. No significant modification was observed in the indexes of diastolic function (quotient of speed of protodiastolic filling/speed of telediastolic filling and time of deceleration of transmitral fluid during diastole) following the treatment period. CONCLUSIONS: Diminution of the left ventricular mass induced by captopril in hypertensive patients is not accompanied by an improvement in ventricular filling. It is suggested that myocardial hypertrophy is not responsible for diastolic dysfunction of arterial hypertension.

Adult↗
PubMed1992

Increased activity of the Na(+)-dependent Cl(-)-HCO3- anion exchanger in erythrocytes of patients with essential hypertension.

OBJECTIVE: To study the activity of the Na(+)-dependent Cl(-)-HCO3- anion exchanger in erythrocytes of patients with essential hypertension. DESIGN: The study was performed in cells from 48 untreated essential hypertensive patients and 30 normotensive controls with similar age- and sex- distribution. METHODS: The activity of the Na(+)-dependent anion exchanger was determined by measuring the 4,4'-diisothiocyanostilbene-2,2'-disulfonate (DIDS) sensitive Li+ influx in fresh cells incubated into a medium containing Li2CO3. RESULTS: The DIDS-sensitive Li+ influx was higher in hypertensives than controls. With the 100% confidence (upper) limit of the normotensive population as a cut-off point, a subgroup of 11 hypertensives had an abnormally high activity of the Na(+)-dependent Cl(-)-HCO3- anion exchanger. Compared with patients with normal exchanger activity, patients with increased exchanger activity were characterized by the following: higher frequency of family history of hypertension; lower serum high-density lipoprotein cholesterol levels and higher plasma aldosterone concentrations. After multiple regression analysis, the DIDS-sensitive Li+ influx was inversely correlated with high-density lipoprotein cholesterol levels. CONCLUSIONS: These results show the presence of a new abnormality of erythrocyte Na+ transport in essential hypertension--increased activity of the Na(+)-dependent Cl(-)-HCO3- anion exchanger. In addition, our findings suggest that from the clinical point of view, patients with this transport abnormality represent a particular subset of essential hypertensives.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1992

[Primary angiosarcoma of the heart. A report of a new case and a review of the literature].

The case is presented of a primitive heart angiosarcoma (PHA) in a 53-year-old woman who developed repeated episodes of hemopericardium with cardiac tamponade. A literature review is performed. PHA is the most frequent primitive cardiac tumor. It is usually localized in the right striatum and is accompanied by effusion of pericardium and right heart failure. The diagnosis is usually made late and bidimensional echography is of great value. Treatment is surgical, if possible. Chemotherapy protocols are being used but with obscure prognosis.

Cardiac Tamponade↗
PubMed1991

[The presence of diastolic dysfunction in hypertensive patients without left ventricular hypertrophy].

BACKGROUND: Hypertension is associated with abnormalities in the diastolic left ventricular function. The present study was performed to evaluate whether diastolic function is impaired independently from myocardial hypertrophy. METHODS: 41 patients with essential hypertension who had never received antihypertensive therapy were evaluated. All patients had normal systolic function. VE wave, or early diastolic filling wave, and VA, or late diastolic filling wave, were measured by Doppler echocardiography, and the VE/VA ratio was used as index of diastolic function. RESULTS: The VE/VA ratio was abnormally reduced in 23 patients, of which only 9 had left ventricular hypertrophy on echocardiographic criteria. The patients with a reduced ratio were older (p less than 0.01) than patients with a normal ratio. VE/VA ratio was not correlated with left ventricular mass, but it was correlated with age (r = 0.4186, p less than 0.01). CONCLUSIONS: Left ventricular diastolic function is impaired in hypertension independently from hypertrophy. The myocardial abnormalities associated with aging might be the major determinants of this functional impairment.

Adult↗
PubMed1991

Abnormal sympathetic and renal response to sodium restriction in compensated cirrhosis.

It has been proposed that in liver cirrhosis portal hypertension causes splanchnic vasodilation and this induces blood volume expansion to maintain blood pressure. The current study was designed to explore the homeostatic response to sodium restriction, a maneuver aiming to contract blood volume, in compensated cirrhosis. Mean blood pressure, sympathetic nervous activity, and proximal sodium reabsorption were evaluated in 16 healthy control and 21 nonazotemic cirrhotic patients (11 without ascites and 10 with ascites) under two experimental conditions: after 4 days on a free sodium diet (basal condition) and after 4 days on a restricted sodium diet (40 mmol/day). No differences were observed in basal conditions in the above parameters between control and cirrhotic patients without ascites. However, cirrhotic patients with ascites showed lower basal values of mean blood pressure and higher basal levels of both plasma norepinephrine and fractional proximal sodium reabsorption than controls. Neither control nor cirrhotic patients with ascites showed significant changes in the measured parameters after sodium restriction. In contrast, in nonascitic patients, this maneuver induced an elevation in plasma norepinephrine concentration (164.4 +/- 24.6 vs. 270.1 +/- 24.9 pg/mL; mean +/- SEM; P less than 0.005) and in fractional proximal sodium reabsorption (86.4 +/- 2.1 vs. 91.8% +/- 0.5%; P less than 0.01). In addition, the nonascitic cirrhotic patients became hypotensive compared with controls (80.9 +/- 1.6 vs. 88.5 +/- 4.8 mm Hg; P less than 0.05) when subjected to the low-sodium diet. In patients without ascites, under conditions of sodium restriction, the decrease in mean arterial pressure correlated inversely with the increase in plasma norepinephrine concentration (r = -0.713; P less than 0.05), whereas the levels of plasma norepinephrine correlated directly with fractional proximal sodium reabsorption (r = 0.893; P less than 0.01). These findings suggest that ineffective circulatory volume is detected in nonascitic cirrhotic patients only under conditions of sodium restriction, but it is always present in cirrhotic patients with ascites, irrespectively of the amount of sodium in the diet. These results are compatible with the existence of fixed arterial vasodilation in cirrhosis.

Adult↗
PubMed1991

[Malignant adenoma of the cervix: a diagnostic and therapeutic dilemma].

"Adenoma malignum" of the cervix is an extremely rare variant of cervical adenocarcinoma. Its diagnosis by means of light microscopy is rendered very difficult by its strong similarity to benign endocervical hyperplasia. During the last few years immunohistochemistry has proved to be of great help in differential diagnosis. Treatment of "adenoma malignum" also poses great problems. Most cases are diagnosed in advanced stages, although only early diagnosis offers the possibility of effective treatment. Radiotherapy has failed in all known cases in an advanced stage of the disease. Chemotherapy is also not promising as a therapeutical option, because the tumour expresses high levels of the multidrug-resistance marker P-glycoprotein.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1991

[Association of cardiovascular risk factors in hypertensive patients with left ventricular hypertrophy].

The cardiovascular morbidity-mortality is higher between the patients with essential hypertension and LVH. It is due to effects over heart provoked by the abnormal increment of the myocardial mass. However, the role of others concurrent risk factors must be determined. To analyze this possibility, we studied the distribution of the main cardiovascular risk factors in a population of 50 essential hypertensive patients non treated before. They were shared in two groups: 32 patients with LVH diagnosed by echocardiography (left ventricular mass index greater than 120 g/m2) and 18 patients without LVH. The comparison between both groups showed that the patients with LVH had higher systolic arterial pressure (p less than 0.05), higher mean arterial pressure (p less than 0.05), higher alcohol (p less than 0.01) and tobacco (p less than 0.02) consumption, higher values of triglycerides (p less than 0.05) and uric acid (p less than 0.01), and higher plasma renin activity (p less than 0.05) than those observed in the group without LVH. Plasma cholesterol was also higher (increase of 11%) in patients with LVH; then, in these patients its mean value (245 +/- 12 mg/dl, M +/- SD) was over the top of the normal limit (240 mg/dl), which discriminate the risk of cardiovascular complications for this factor. The following factors: age, sex distribution, diastolic arterial pressure, sedentary life and carbohydrate intolerance, didn't present differences between the groups. These results show that hypertensive patients with LVH, as a group, have others factors of risk, different from ventricular hypertrophy, which favour the high cardiovascular morbidity-mortality of LVH group.

Adult↗
PubMed1990

Foot-and-mouth disease virus strains isolated from persistently infected cell cultures are attenuated for mice and cattle.

It was previously reported that during serial passage of a BHK-derived cell line persistently infected with foot-and-mouth disease virus, (termed C1-BHK-Rc1) the virus became increasingly more virulent for BHK-21 cells (de la Torre et al 1988). Virus strains isolated from different cell passage levels were tested for virulence in mice and cattle. The results showed that in the course of persistence in BHK cells, FMDV became progressively less virulent for mice and cattle.

Animals↗
PubMed1990

Correspondences between the activity of the renin-angiotensin system and the erythrocyte Na+ transport abnormalities in hypertension.

Plasma renin activity and the relationship of renin activity and sodium excretion were analyzed in 50 untreated essential hypertensives classified according to their erythrocyte Na+ transport abnormalities. Renin activity was inappropriately high in 7 patients with increased activity of Na+,Li+ countertransport, inappropriately low in 12 patients with decreased activity of Na+,K+,Cl- cotransport and normal in 31 patients without either Na+ transport abnormalities. These results suggest that there are correspondences between the activity of the renin-angiotensin system and the main Na+ transport abnormalities present in erythrocytes of patients with essential hypertension.

Adolescent↗
PubMed1990

Alterations of the Cl-/NaCO3- anion exchanger in erythrocytes of uraemic patients.

We have studied the transport activity of the erythrocyte anion exchanger by measuring the DIDS-sensitive Li+ influx in fresh red blood cells incubated in HCO3- medium. In addition, the amount of erythrocyte band 3 protein was determined by electrophoretic analysis. The study was performed in twenty uraemic patients on chronic haemodialysis (12 males and 8 females, mean age 47.9 years), and in 20 healthy controls (10 males and 10 females, mean age 44.7 years). Mean time on haemodialysis was 63.9 months (range 6-170 months). The DIDS-sensitive Li+ influx was decreased in erythrocytes from uraemic patients as compared to erythrocytes from controls (619.6 +/- 34.1 vs 761.2 +/- 36.6 mumol/l cell x h, P less than 0.01). The content of band 3 protein was decreased in erythrocytes from uraemic patients as compared to erythrocytes from controls (30.01 +/- 0.39 vs 32.12 +/- 0.48%, P less than 0.01). These results indicate that the Cl-/NaCO3- anion exchanger is altered in erythrocytes from uraemic patients in chronic haemodialysis, and suggest that the regulation of ion content may be compromised in the red blood cells of these patients.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1990

Unique amino acid substitutions in the capsid proteins of foot-and-mouth disease virus from a persistent infection in cell culture.

Maintenance of a persistent foot-and-mouth disease virus (FMDV) infection in BHK-21 cells involves a coevolution of cells and virus (J. C. de la Torre, E. Martínez-Salas, J. Díez, A. Villaverde, F. Gebauer, E. Rocha, M. Dávila, and E. Domingo, J. Virol. 62:2050-2058, 1988). The resident FMDV undergoes a number of phenotypic changes, including a gradual decrease in virion stability. Here we report the nucleotide sequence of the P1 genomic segment of the virus rescued after 100 passages of the carrier cells (R100). Only 5 of 15 mutations in P1 of R100 were silent. Nine amino acid substitutions were fixed on the viral capsid during persistence, and three of the variant amino acids are not represented in the corresponding position of any picornavirus sequenced to date. Cysteine at position 7 of VP3, that provides disulfide bridges at the FMDV fivefold axis, was substituted by valine, as determined by RNA, cDNA, and protein sequencing. The modified virus shows high buoyant density in cesium chloride and depicts the same sensitivity to photoinactivation by intercalating dyes as the parental FMDV C-S8c1. Amino acid substitutions fixed in VP1 resulted in altered antigenicity, as revealed by reactivity with monoclonal antibodies. In addition to defining at the molecular level the alterations the FMDV capsid underwent during persistence, the results show that positions which are highly invariant in an RNA genome may change when viral replication occurs in a modified environment.

Amino Acid Sequence↗
PubMed1990

[The current focus on cardiovascular growth in arterial hypertension].

Recent data have demonstrated that together with an impulsive-conductive function, the cardiovascular system is an organ that synthesizes and secretes several substances involved in the local regulation of its properties. This is the case of endothelial cells and cardiovascular myocytes which produce vasoactive substances and growth factors capable of modulating intra-, auto-, and paracrinally [correction of paraclinically] cardiovascular contractility and growth. It is currently postulated that different genetic or acquired abnormalities in the production of one or more than one of these substances and/or in the response to them, could provoke an excessive increase and/or a disordered growth of the cardiovascular muscles cells. At the same time, both abnormalities could contribute to the initiation and the development of arterial hypertension. The new antihypertensive drugs could be targeted to the cardiovascular endocrine systems.

Cardiovascular System↗
PubMed1990

[Significance and implications of the anomalies in transmembrane transport of sodium in essential arterial hypertension].

There is now some sort of agreement between different investigators regarding red blood cell Na+ transport in essential hypertension. This concerns at least two points: a) Na+ transport function is abnormal in erythrocytes from an important number of essential hypertensive patients, and b) the population of hypertensive patients is heterogeneous with respect to the different abnormalities in Na+ transport function. In contrast with the very large number of fundamental studies of Na+ transport in erythrocytes from essential hypertensive patients, very little is known concerning the clinical relevance of these findings. This review focuses on the etiopathogenic and pathophysiologic meaning of Na+ transport abnormalities which may be useful to the diagnosis and/or treatment of hypertensive patients.

Antihypertensive Agents↗
PubMed1989

Rat atrial natriuretic peptide stimulates K+ fluxes in human erythrocytes.

Ouabain- and bumetanide-resistant potassium fluxes were measured in human erythrocytes incubated in a medium containing calcium and a calcium ionophore. Pharmacological concentrations of rat atrial natriuretic peptide stimulated these fluxes. Although human erythrocytes lack atrial natriuretic peptide receptors, our results suggest that the hormone can modify transmembrane K+ movements.

Animals↗
PubMed1989

Immunological approach to the regulation of nitrate reductase in Monoraphidium braunii.

The effects of different culture conditions on nitrate reductase activity and nitrate reductase protein from Monoraphidium braunii have been studied, using two different immunological techniques, rocket immunoelectrophoresis and an enzyme-linked immunosorbent assay, to determine nitrate reductase protein. The nitrogen sources ammonium and glutamine repressed nitrate reductase synthesis, while nitrite, alanine, and glutamate acted as derepressors. There was a four- to eightfold increase of nitrate reductase activity and a twofold increase of nitrate reductase protein under conditions of nitrogen starvation versus growth on nitrate. Nitrate reductase synthesis was repressed in darkness. However, when Monoraphidium was grown under heterotrophic conditions with glucose as the carbon and energy source, the synthesis of nitrate reductase was maintained. With ammonium or darkness, changes in nitrate reductase activity correlated fairly well with changes in nitrate reductase protein, indicating that in both cases loss of activity was due to repression and not to inactivation of the enzyme. Experiments using methionine sulfoximine, to inhibit ammonium assimilation, showed that ammonium per se and not a product of its metabolism was the corepressor of the enzyme. The appearance of nitrate reductase activity after transferring the cells to induction media was prevented by cycloheximide and by 6-methylpurine, although in this latter case the effect was observed only in cells preincubated with the inhibitor for 1 h before the induction period.

Ammonia↗
PubMed1989

Is there increased cardiovascular risk in essential hypertensive patients with abnormal kinetics of red blood cell sodium-lithium countertransport?

Na+ transport kinetics were studied in red blood cells (RBCs) from 50 essential hypertensive patients and 30 normotensive controls. Seven hypertensive patients were characterized by the following: (1) a maximal rate of Na+-Li+ countertransport higher than an upper normal limit of 525 mumol.litre cells-1.h-1; (2) an apparent dissociation constant for internal Na+ higher than an upper normal limit of 20.4 mmol.litre cells (in only five of the seven hypertensives); (3) no other kinetic abnormality in Na+,K+ pump, Na+,K+ cotransport or passive Na+ permeability. Clinically, hypertensives with abnormal countertransport were characterized by high serum low-density lipoprotein (LDL) cholesterol levels and the presence of electrocardiographic left ventricular hypertrophy (LVH). Conversely, mean values of these two clinical parameters were normal in the remaining hypertensive patients, independently of the presence of other abnormalities in Na+,K+ pump, Na+,K+ cotransport or passive Na+ permeability. In conclusion, the presence of abnormal Na+-Li+ countertransport kinetics in erythrocytes may be associated with an enhanced cardiovascular risk in hypertension.

Adolescent↗