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Biomedical subjects

C Abad

Publications and source records attributed to C Abad.

At least 109 records · Page 6Linked to original sources
PubMed1988

Improvement of renal function in azotaemic hypertensive patients after surgical revascularization.

Between 1974 and 1986, 17 patients (16 men and 1 woman) with renal insufficiency (serum creatinine greater than 1.5 mg/dl, mean 3.75 mg/dl), with a mean age of 51.3 years, underwent surgical renal revascularization. Two of them were on maintenance haemodialysis. All were severely hypertensive in spite of antihypertensive drugs. Atherosclerosis was the cause of renal stenosis in 14 cases and fibromuscular dysplasia in 3. Operative procedures included splenorenal shunt (5), autotransplantation (3), aortorenal bypass (3), hepatorenal bypass (1), bilateral renal endarterectomy (1), renal ostial closure (1) and nephrectomy (3). Mean serum creatinine showed a decrease from 3.76 to 1.65 mg/dl (P less than 0.005). Mean arterial pressure dropped from 161 mmHg to 103 mmHg (P less than 0.001). Systolic and diastolic pressures also showed significant decreases. Two patients died. Four patients required a second operation and the renal function and blood pressure then improved. Renovascular disease must be ruled out in patients with renal insufficiency associated with hypertension, including those patients on haemodialysis. We conclude that renal revascularization surgery is a reliable and efficient form of treatment in selected cases of renal failure of renovascular origin.

Blood Pressure↗
PubMed1988

A study of the conformational equilibrium of DL-oligophenylalanines in nonpolar solvents in the presence and absence of lipids by high-performance liquid chromatography.

The usefulness of high-performance size-exclusion liquid chromatography (HPSEC) for the separation of dimeric and monomeric species of DL-alternating oligophenylalanines is demonstrated for the first time. The experimental data obtained as a function of time fit a simple dimer-monomer equilibrium in a nonpolar solvent such as tetrahydrofuran. A higher extent of monomerization and a decrease in the time required for reaching equilibrium were detected in the presence of either water or phosphatidylcholine. The analysis of the relative proportions of the two separated species under equilibrium conditions has allowed the influence of the oligopeptide chain length on the stability of dimeric species to be determined. The advantages of this methodology, in combination with spectroscopic techniques, in studies on autoassociating peptides are considered.

Chromatography, High Pressure Liquid↗
PubMed1988

Analysis of the binding of Ca2+ to gramicidin A in ethanol in terms of the dimer-monomer conformational equilibrium.

This study reports the first direct observation of the binding of Ca2+ to gramicidin A in ethanol, analysed in terms of the polypeptide dimer-monomer conformational equilibrium. High performance size-exclusion chromatography has been successfully used to elucidate the binding mechanism and to determine the rate constants as well as the stoichiometry of the processes involved. In addition, fluorescence intensity and anisotropy measurements have revealed a dependence of the number of accessible Ca2+-binding sites on the peptide concentration.

Calcium↗
PubMed1988

Renal hemangioma and renal artery aneurysm in the Klippel-Trenaunay syndrome.

We describe a young woman with the Klippel-Trenaunay-Weber syndrome in whom gross unilateral hematuria developed. A renal arteriogram showed a left renal artery aneurysm. Artery reconstruction was impossible and left nephrectomy was performed. Pathological examination showed multiple renal pelvic hemangiomas as the cause of the gross hematuria.

Adult↗
PubMed1988

Reversal of renal failure after revascularization in atheromatous renovascular disease. Report of two cases.

We report 2 patients with severe renal failure and hypertension secondary to atherosclerotic renovascular disease who required hemodialysis. Successful surgical revascularization in these patients resulted in the recovery of renal function (twice in a patient) and in controlling the blood pressure. These results indicate that in the presence of severe renal artery obstruction renal parenchyma may be preserved, while renal function is absent. We highlight the usefulness of preoperative renal arteriography for evaluation of the affected vessel and the demonstration of collateral circulation and the value of preoperative renal biopsy in the prediction of the viability of the kidney parenchyma.

Aorta, Abdominal↗
PubMed1986

Conformational species of gramicidin A in non-polar solvent. A kinetic and thermodynamic treatment in the absence and presence of phosphatidylcholine as studied by high-performance liquid chromatography.

A kinetic and thermodynamic study has been carried out to characterize quantitatively the conformational equilibrium of gramicidin A (GA) in tetrahydrofuran at different peptide concentrations in the absence and presence of egg yolk phosphatidylcholine by using size-exclusion high-performance liquid chromatographic analysis. In the absence of lipid, the experimental data fit a simple dimer-monomer equilibrium, the rate and equilibrium constants for the dissociation process being (1.6 +/- 0.7) X 10(-7) s-1 and (8.5 +/- 0.3) X 10(-6) M, respectively. A higher extent of monomerization and a decrease in the time required for reaching equilibrium are detected in the presence of phospholipid, the kinetic and thermodynamic effects depending on both lipid and GA concentrations. In order to account for these observations a cyclic equilibrium mechanism is proposed which is analysed in terms of four conformational species, namely, free monomer, free dimer, lipid-bound monomer and lipid-bound dimer. The results obtained are discussed in relation to recent literature data on lipid-protein interactions.

Chromatography, High Pressure Liquid↗
PubMed1985

Aneurysm of the gastroduodenal artery. Surgical treatment in an asymptomatic case.

Aneurysms of the gastroduodenal artery are very rare. We present the case of a 51-year-old female with an asymptomatic gastroduodenal artery aneurysm which was discovered by means of arteriography. The patient was surgically treated by proximal and distal ligation of the gastroduodenal artery and partial resection of the aneurysm. Preoperative and postoperative arteriograms are shown. Seven months after the operation the patient remains asymptomatic. We comment on and review other cases in the English language literature.

Aneurysm↗
PubMed1985

Early results with intraoperative transluminal coronary artery balloon dilatation.

We used intraoperative transluminal coronary balloon dilatation, together with coronary artery bypass grafting, to obtain complete myocardial revascularization in extensively diseased coronary arteries. Our patient population consisted of ten males and two females, with a mean age of 58 years. The left anterior descending artery was dilated in five patients, the posterior descending artery was dilated in three, the obtuse marginal artery in two, the left circumflex artery in one, and the right coronary artery in one. Additionally, a mean of 2.81 grafts per patient were placed. Hospital mortality was one patient (8.33%). There was also one case of perioperative myocardial infarction. Postoperative angiography was done in seven patients: five were shown to be improved, one had a vessel that appeared unchanged, and one had an occluded vessel. We found intraoperative transluminal coronary balloon dilatation to be a simple and efficient technique that offers potential improvement in myocardial revascularization.

Journal Article↗
PubMed1981

Dilatometric, refractometric and viscometric study of lysozyme-cation interaction.

The interaction between hen egg-white lysozyme and Cu(II) or Co(II) cations has been studied by dilatometry, equilibrium dialysis-differential refractometry and viscometry at different metal cation concentrations. Delta V isotherms in copper and cobalt solutions have been obtained from dilatometry. Preferential adsorption parameters and specific viscosity have been determined from refractometric and viscosimetric measurements. It has been observed that this interaction produces structural alterations in lysozyme. The magnitude of these conformational changes depends on the metal ion and protein concentration. The results obtained using the three techniques are in good agreement.

Animals↗
PubMed1979

[Effects of T3, T4 and methyltiouracile short-term treatments on plasma and liver lipid levels in rats (author's transl)].

The effects of short-term administration of thyroid hormones (T3 and T4) and methyltiouracile (MTU) on liver and plasma lipid levels in female rats have been comparatively studied T3 increases the levels of all the studied liver lipids and decreases the plasma lipids. T4 produces smaller and even, in some cases (liver triglycerides and cholesterol esters), opposite effects. The administration of MTU produces, in general, opposite effects to T3 and T4.

Animals↗
PubMed1979

[Effect of progesterone on rat plasma and liver lipid levels (author's transl)].

The effect of progesterone upon several lipidic parameters on rat liver and plasma was studied. Progesterone administration led to a significant increase in the hepatic triacylglyceride and cholesterol esterified levels and to a decrease in the phospholipid content. After progesterone treatment decreases in plasma total lipids, phospholipids, cholesterol and cholesterol esterified were observed, whereas plasma triacylglyceride and free fatty acid levels increased. The hormonal treatment altered the lipoprotein pattern, which significantly reduced the beta-lipoprotein fraction.

Animals↗
PubMed1976

Age differences in the positional distribution of phosphoglycerides and molecular species of choline phosphoglycerides during development of the chick embryo liver.

The total fatty acid composition and the distribution of acyl groups in the positions 1 and 2 of 1,2-diacyl-sn-glycero-3-phosphocholine and 1,2-diacyl-sn-glycero-3-phosphoethanolamine as well as in the molecular species of 1,2-diacyl-sn-glycero-3-phosphocholine from the chick embryo liver have been investigated at various stages of development. The fatty acid content of the main lipid classes from the yolks was also evaluated. The relative percentages of total saturated fatty acids in 1,2-diacyl-sn-glycero-3-phosphocholine remained constant during liver development; however, the levels of both main saturated acids, palmitic and stearic acids, were reciprocally counterbalanced as the age of the embryo proceeded. On the other hand, arachidonic acid decreased with time whereas linoleic acid and docosahexaenoic acid doubled their proportions during development. The relative amounts of total saturated fatty acids from liver 1,2-diacyl-sn-glycero-3-phosphoethanolamine were also constant during all stages of development; however, palmitic/stearic acid ratio did not change with time in this phosphoglyceride. Fatty acid composition of the yolk phosphoglycerides did not change during embryonic development. It should be noted that marked differences between fatty acid composition of choline and ethanolamine phosphoglycerides from the embryo liver and those of the yolk phosphoglycerides were demonstrated. The general patterns of the positional distribution of the acyl groups in choline phosphoglycerides differed from those of ethanolamine phosphoglycerides. Palmitic and stearic acids were only positioned at position 1 in 1,2-diacyl-sn-glycero-3-phosphoethanolamine whereas both fatty acids did not acylate exclusively the position 1 in 1,2-diacyl-sn-glycero-3-phosphocholine.

Animals↗
PubMedDate not supplied

Primary cardiac paraganglioma. Case report and review of surgically treated cases.

A 58 year old man with an infiltrating non-resectable left atrial paraganglioma was diagnosed by sternotomy and open biopsy. The patient remains symptom free 16 months after the operation. No evidence of an increase in the size of the tumour has been detected by echocardiography. The literature regarding surgically treated patients with cardiac paragangliomas is reviewed.

Heart Atria↗