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Biomedical subjects

J Diez

Publications and source records attributed to J Diez.

At least 55 records · Page 3Linked to original sources
PubMed1993

[Papillary and cystic tumors of the pancreas. Clinico-pathological, cytopathological, immunohistochemical, and nuclear ploidy study].

Seven cases of PCNP were studied; 5 females and 2 males, ages ranging from 21 to 68 years (mean 39). All had asymptomatic masses located in the head (3), body (2), isthmus (1) and tail (1). In 4 of them fine-needle aspiration (FNA) was done and showed a diagnostic pattern with papillary clusters as well as isolated epithelial cells with monomorphic appearance, round nuclei and inconspicuous nucleoli; 5 cases had a surgical resection and only 2 a biopsy due to unresectable tumors. Histologically, they showed the typical features of PCNP with solid, papillary, trabecular and cystic patterns. IHQ studies showed positivity for cytokeratin (n = 5), alpha-1-antitrypsin (n = 4), monoclonal NSE (n = 3), chromogranin (n = 3) and estrogen receptors (n = 1). All cases were negative for insulin, glucagon, somatostatin, EMA and CEA. DNA analysis done with an image analyzer showed 4 diploid tumors, 2 diploid-tetraploid an 1 aneuploid tumor. One patient died because of postoperative complications and the remaining 6 are alive with a mean follow-up of 17 months (2-36). We emphasize the diagnostic appearance of the tumor on FNA, and the low grade malignant potential of this neoplasm supported by the predominance of diploid tumors. Our IHQ findings suggest both an exocrine and endocrine differentiation.

Adult↗
PubMed1992

Monitoring endometrial adenocarcinoma with a four tumor marker combination. CA 125, squamous cell carcinoma antigen, CA 19.9 and CA 15.3.

The combined value of four tumor markers, in the follow-up of endometrial adenocarcinoma, is analyzed. Cancer antigen 125 (CA 125), squamous cell carcinoma antigen (SCC), carbohydrate antigen 19.9 (CA 19.9) and carbohydrate antigen 15.3 (CA 15.3) were used in 213 evaluations from 105 patients. Sensitivity as regards recurrence or progression of disease was 45% (CA 125), 9% (SCC), 51% (CA 19.9) and 21% (CA 15.3). Specificities as regards the 'no evidence of disease' ranged from 95% to 99%. Single tumor marker efficiency ranged from 90% for CA 125 to 84% for SCC (p = 0.08). With the two tumor marker combination sensitivity increased up to 77% achieved with CA 125-CA 19.9, but efficiency increased only slightly (92.0% for CA 125-SCC). In the best three tumor marker combination, a sensitivity of 85% was achieved (CA 125-CA 19.9-CA 15.3), and an efficiency of 92.2%. The simultaneous use of the four tumor markers did not improve assay results. The possibility of recurrence or progression of disease in some combinations was very low (4.6% when CA 125 and CA 19.9 negative, 3% when CA 125, CA 19.9 and CA 15.3 negative), a fact to be considered in order to avoid aggressive management in such cases. The tumor markers were of limited value for the prediction of recurrences. The suggestion of recurrence when the increase in tumor markers was the only finding was confirmed in only 7%, while confirmation was made in 100% when there was another pathological finding.

Adenocarcinoma↗
PubMed1992

Abnormalities of renal function in essential hypertension with increased circulating levels of insulin-like growth factor I.

An increase in glomerular filtration rate and in tubular Na+ reabsorption from the parenteral administration of insulin-like growth factor I (IGF-I) have been reported in human subjects. To evaluate whether glomerular hyperfiltration and Na+ hyper-reabsorption present in some essential hypertensives are associated to an excess of IGF-I, the plasma levels of this factor and several parameters of renal function were studied in 30 non-treated essential hypertensives and in 30 normotensive controls. IGF-I levels were higher in hypertensive as compared to controls. With the 95% (upper) limit of the normotensive population as a cut-off point, a subgroup of six hypertensives had an abnormally high IGF-I level. Mean blood pressure was slightly lower in these six patients (112 +/- 7 mmHg) than in the remaining patients (120 +/- 2 mmHg). As compared to normotensives and hypertensives with normal IGF-I levels, patients with increased IGF-I levels were characterized by lower (P < 0.01) fractional Na+ excretion and higher (P < 0.05) creatinine clearance. The analysis of the relation of plasma renin activity and the concurrent daily rate of Na+ excretion showed that patients with increased IGF-I were low-renin hypertensives and patients with normal IGF-I were normal-renin hypertensives. These results indicate that an association exists between exaggerated circulating levels of IGF-I and abnormalities of renal function present in some patients with essential hypertension. It is suggested that IGF-I can play a role in low-renin essential hypertension.

Absorption↗
PubMed1991

Human immunodeficiency virus-induced immunosuppression: a risk factor for human papillomavirus infection.

In a group of 92 women with genital condylomata, 15 (16.3%) human immunodeficiency virus-positive patients were found, whereas no case was detected in a control group of 100 women. The relative risk was greater than 19.28. Human immunodeficiency-positive status was associated with other parameters: lower age and parity, major frequency of induced abortions, and sexually transmitted diseases. Thus although human immunodeficiency-positive status seems to be a true risk factor in relation to the altered immunologic state, an indirect association cannot be discarded. Such patients should be screened closely for human papillomavirus infection and cervical cancer. Among human immunodeficiency-positive women, a more resistant behavior of human papillomavirus-associated lesions was detected (recurrence-persistence of 41.7% versus 12%), a fact that might also be in relation to the immunodepressed status.

Biopsy↗
PubMed1991

Repeat pregnancy associated with cardiac pacemaker.

Two pregnancies in a patient with a fixed-rate pacemaker are reported. The first pregnancy was uneventful. The second had no maternal complications either. A moderate tachysystolia was detected during the second period. The newborn was delivered with forceps applied under spinal anesthesia. Newborn infant evolution presented no hazards, but umbilical cord analysis revealed a severe acidosis, in spite of a normal scalp analysis 45 min earlier. Epidural anesthesia is recommended for such patients.

Acidosis↗
PubMed1991

Elevated levels of parathyroid hormone in essential hypertensive patients with increased erythrocyte potassium efflux.

Previous observations suggest that Ca(2+)-dependent K+ efflux is increased in erythrocytes from spontaneously hypertensive rats. On the other hand, it has been reported that hyperparathyroidism induces an increase in Ca(2+)-dependent K+ efflux of human erythrocytes. To investigate whether Ca(2+)-dependent K+ efflux is altered in essential hypertension quinine-sensitive K+ efflux was measured in erythrocytes from 20 normotensive controls and 30 nontreated essential hypertensives. The quinine-sensitive K+ efflux was similar for hypertensive patients (593 +/- 20 mmol/L cells/h) as compared with normotensive controls (532 +/- 34 mmol/L cells/h). Ten hypertensives exhibited values of quinine-sensitive K+ efflux above an upper normal limit of 650 mmol/L cells/h. As compared with controls those patients presented elevated plasma levels of parathyroid hormone (P less than .05). In addition, a positive correlation was found between parathyroid hormone and quinine-sensitive K+ efflux in the above ten hypertensives (R = 0.85, P less than .001). These results suggest that an excess of parathyroid hormone may be involved in the increase of Ca(2+)-dependent K+ efflux present in some essential hypertensive patients.

Adult↗
PubMed1991

Immunocytochemical localization of nitrite reductase in green algae.

The distribution of nitrite reductase (EC 1.7.7.1) in the green algae Chlamydomonas reinhardtii, Monoraphidium braunii, Chlorella fusca, and Scenedesmus obliquus was studied by immunoelectron microscopy. The labeling of ultrathin cryosections was performed with anti-nitrite reductase antibodies followed by gold-labeled goat anti-rabbit antibodies. In C. reinhardtii sections, gold label was mainly associated with the pyrenoid, tonoplast, and plasmalemma. Significant labeling was also detected in the thylakoid region. In all other organisms, label density was lower but distributed in the same locations, except that the plasmalemma of S. obliquus was not significantly labeled. From estimates of the relative volume of different cell regions, we found that approximately 80% of the total enzyme is located in the chloroplastic region (thylakoids plus pyrenoid) of C. reinhardtii, M. braunii, and C. fusca, and 97% in the case of S. obliquus.

Journal Article↗
PubMed1991

Enhanced renal PGE2 in hypertensives with increased red cell Na(+)-Li+ countertransport.

In this study, maximal velocities of Na(+)-Li+ countertransport were measured in red blood cells of 50 untreated essential hypertensives and 30 normotensive controls. In addition, urinary excretion of renal prostaglandins (PG) and plasma renin activity (PRA) was measured in each subject. Maximal velocity of Na(+)-Li+ countertransport was above the upper limit in controls of 525 mumol.l cell-1.h-1 in seven patients and was normal in the remaining patients. Patients with increased countertransport did not differ significantly from controls and from patients with normal countertransport with regard to urinary excretion of 6-keto-PGF1 alpha (the stable metabolite of prostacyclin) and thromboxane B2 (TxB2) (the stable metabolite of thromboxane A2). In contrast, mean values of PGE2 were significantly higher (P less than 0.01) in patients with increased countertransport (411 +/- 39 pg/min) compared with patients with normal countertransport (181 +/- 15 pg/min) and controls (146 +/- 13 pg/min). In addition, six patients with increased countertransport exhibited urinary levels of PGE2 higher than the upper limit in controls. Hypertensives with increased countertransport showed enhanced PRA when compared with the remaining patients (2.96 +/- 0.50 vs. 1.30 +/- 0.52 ng.ml-1.h-1, P less than 0.05) and with controls (1.86 +/- 0.08 ng.ml-1.h-1, P less than 0.05). Finally, the relationship between PGE2 and PRA was found to be significant in patients with increased countertransport (r = 0.776, P less than 0.05). These results indicate that renal synthesis of PGE2 is enhanced in essential hypertensives with increased Na(+)-Li+ countertransport activity and hyperreninemia.

Adult↗
PubMed1991

Is the erythrocyte sodium-lithium countertransport a molecular marker of cardiac risk in hypertension?

Current research is being directed toward the identification of markers of cardiac risk in hypertension, according to demographic, clinical, genetic, challenge-response and laboratory predictors. Much interest has centered around cationic transporters as laboratory markers, not only because they might make good predictors of cardiac risk, but also because of their potential for explaining the pathophysiology of that disorder. To date, there is no cationic transporter that clearly discriminates between subjects with low and with high cardiac risk, although the sodium-lithium (Na(+)-Li+) countertransport in red blood cells has come the closest. High rates of Na(+)-Li+ countertransport have been found to be associated not just with essential hypertension but more specifically with subgroups of patients suffering from essential hypertension who have a higher frequency of severe hypertension and increased risk of cardiac disease. Here, we examine different lines of clinical evidence suggesting that increased Na(+)-Li+ countertransport activity may identify patients with essential hypertension who are at an increased risk of cardiac disease because they also present other cardiac risk factors, namely hyperlipidemia and/or left ventricular hypertrophy. In addition, the pathophysiological basis for the association of hypertension and the above cardiac risk factors with increased Na(+)-Li+ countertransport are discussed.

Antiporters↗
PubMed1990

Diuretics and transmembrane ionic exchanges: structure-activity relations and clinical applications.

The study of membrane ion transport has facilitated the discovery of potent and quite specific inhibitory drugs. Some of these compounds are therapeutic agents acting on basic transport mechanisms as in the case of the cardiac glycosides on the myocardial sodium ion (Na+), potassium ion (K+) pump, and the loop diuretics on the renal Na+, K+, chloride (Cl-) co-transport system. The development of inhibitors for other transport systems such as Na+/hydrogen ion (H+), Na+/calcium ion (Ca2+) and bicarbonate (HCO3-)/Cl- exchangers requires the screening of a large number of molecules. For several reasons, the human red blood cell is one of the best models for screening the effect of drugs on ion transport mechanisms. The use of human red cells for pharmacologic studies of ion transport has increased the understanding of the structure-activity relations of diuretics. For instance, loop diuretics that are chemically neutral were considered for many years as drugs that act similarly to classic acid loop diuretics. They are now considered as potent inhibitors of HCO3-/Cl- anion exchange. A brief summary of the more recent results is given together with the perspectives of new fundamental and therapeutic applications of these compounds.

Diuretics↗
PubMed1990

Prenatal deficiency of phosphate, phosphate supplementation, and rickets in very-low-birthweight infants.

A preliminary study showed that placental histology was abnormal for babies who subsequently had rickets. The findings--low plasma phosphate concentration; maximum percentage tubular reabsorption of phosphate; and high urinary calcium loss--are those of renal conservation of phosphate in the presence of phosphate deficiency. In a controlled trial no baby receiving phosphate supplements (50 mg per day) had radiological evidence of rickets whereas bone changes were apparent in 42% of the control group. Prenatal deficiency of phosphate, due to placental insufficiency, can be corrected by phosphate supplementation thereby preventing rickets of prematurity.

Calcium↗
PubMed1990

Renal siderosis in patients with heart-valve prostheses: clinical implications.

We have studied the clinical and morphological implications of renal siderosis, reviewing the autopsy protocols of 33 patients with valve prostheses in the heart. Seventeen patients had variable amounts of iron in the proximal tubules of the kidney. Renal siderosis was more frequent in women, in patients with longest time of evolution from the surgical procedure, and in patients with two valve prostheses. Histologically three degrees of renal siderosis may be defined: mild and moderate degrees of iron overload do not alter the kidney architecture, but kidneys, with severe siderosis show tubular atrophy and interstitial fibrosis. Episodes of acute renal failure (ARF) were more frequent in patients with more pronounced iron deposits, especially in the premortem stages. We conclude that renal siderosis may damage the proximal tubular epithelium of patients with valve prostheses in the heart; patients with renal overload of iron are more susceptible to episodes of ARF.

Acute Kidney Injury↗
PubMed1990

Tubular sodium handling in cirrhotic patients with ascites as analysed by the renal lithium clearance method.

The proximal and distal sodium reabsorption were calculated from lithium clearance in 21 healthy controls and 24 cirrhotic patients with ascites after 4 days under a sodium-restricted diet. The values of fractional lithium clearance were lower in patients than in controls (7.37 +/- 0.87 vs. 18.13 +/- 1.76%, P less than 0.001). Fractional proximal sodium reabsorption was increased in patients compared with controls (92.8 +/- 1.1 vs. 81.8 +/- 1.7%, P less than 0.001). No differences were found in fractional distal sodium reabsorption between controls and patients (96.9 +/- 0.8 vs. 98.6 +/- 0.1%). When patients were separated into two subgroups according to their sodium balance, it was found that fractional distal sodium reabsorption was increased in patients whose balance remained positive, compared with patients on a negative sodium balance (98.99 +/- 0.26 vs. 94.11 +/- 1.50%, P less than 0.05). In addition, the natriuretic response to a specific dose of spironolactone was higher in patients on positive sodium balance compared with patients on negative sodium balance (per cent increase in natriuresis after spironolactone 300 mg day-1: 355.24 +/- 73.98 vs. 84.21 +/- 15.8%, P less than 0.01). We conclude that proximal sodium reabsorption is increased in cirrhotics with ascites. In addition, distal sodium reabsorption is enhanced only in those patients which exhibit avid sodium retention.

Adult↗
PubMed1990

Effects of platelet activating factor on contractile force and 45Ca fluxes in guinea-pig isolated atria.

1. The effects of platelet activating factor (PAF) were studied on the electromechanical properties and 45Ca2+ fluxes of guinea-pig isolated atria. 2 Both in spontaneously beating and electrically driven atria, PAF (10(-12)-10(-7) M) increased atrial rate but produced a biphasic effect on contractile force. At low concentrations (up to 10(-10) M) it produced a positive inotropic effect, while at higher concentrations PAF exerted a negative inotropic effect. A similar biphasic effect was observed in the slow contractions elicited by isoprenaline in K(+)-depolarized atrial fibres. 3. The positive inotropic effect of PAF was prevented by verapamil, whereas pretreatment of atria with propranolol, phentolamine, indomethacin or atropine did not modify its positive and negative inotropic actions. BN 52021, a specific PAF antagonist, abolished both the positive and negative inotropic effects. 4. PAF had no effect on the characteristics of the action potentials recorded in either normally polarized or K(+)-depolarized (slow action potential) atrial fibres. 5. At concentrations at which it increased contractile force, PAF potentiated the contractile responses to Ca2+ (0.9-9 mM), whereas at negative inotropic concentrations it inhibited them. The negative inotropic effect of PAF was partially reversed in 70% Na+ medium. 6. At 10(-11) M, PAF increased 45Ca2+ uptake and reduced the rate coefficient (kcm) for the 45Ca2+ efflux. This increase in 45Ca2+ uptake was abolished in atria pretreated with verapamil or BN 52021. However, 10(-7) M PAF modified neither 45Ca2+ uptake nor efflux in atrial muscle. 7. These results suggest that in guinea-pig atria the biphasic inotropic effects of PAF cannot be explained through modifications in the slow inward Ca2+ current or in Na'-Ca2+ exchange, but may be related to changes in trans-sarcolemmal Ca2 + entry mediated by specific PAF receptors.

Action Potentials↗
PubMed1990

Loss of renal graft due to recurrent IgA nephropathy with rapidly progressive course: an unusual clinical evolution.

Recurrence of IgA nephropathy following renal transplantation has been described in 40-50% of patients, and it usually has a good outcome. We present the case of a 54-year-old man with IgA nephropathy who developed terminal renal failure in 1985, 3 years after the onset of the disease. In March 1986 he received a cadaveric renal allograft following treatment with ciclosporin and steroids. Eight months later he developed microhaematuria and proteinuria and 10 months later he developed acute nephritic syndrome and rapidly progressive renal failure. Renal biopsy disclosed an IgA nephropathy with epithelial crescents in 60% of glomeruli. Treatment with plasma exchange and cyclophosphamide was unsuccessful and the patient lost his graft and returned to regular haemodialysis 15 months after renal transplantation.

Acute Kidney Injury↗