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Biomedical subjects

M Fernández

Publications and source records attributed to M Fernández.

At least 19 recordsLinked to original sources
PubMed1992

[Quality of life in arterial hypertension].

BACKGROUND: Quality of life is a key issue for the consideration of hypertension therapy. However, reliable and sensitive evaluation methods are not available in Spain. To this end, a quality of life questionnaire has been elaborated, its yield has been evaluated, and the influence of hypertension and several associated variables on the quality of life has been assessed. METHODS: A questionnaire on quality of life consisting of 62 items was elaborated. Its final evaluation was divided in an overall value and in four subindexes related with anxiety, depression, side effects, and somatic complaints. It was applied to two groups of hypertensive patients, one from hospital care (n = 90) and another from primary care (n = 89), and to a control group (n = 76). RESULTS: Although both populations with hypertension were significantly different regarding age, sex, use of therapies, organic impact and blood pressure, they were overall similar in quality of life. However, quality of life was different from that in control group, which showed better indices. In the hypertensive population, sex, severity of hypertension, type of therapy or duration of the disease did not have any influence on quality of life. CONCLUSIONS: The overall similar quality of life in both hypertensive groups (in spite of the many significant differences in their descriptive features) and the different quality of life between hypertensive and normotensive individuals (in spite of the similitude of their demographic parameters) suggest that the diagnosis of hypertension has by itself a greater influence on the quality of life than several hypertension-associated variables. It has also been found that the method used was sensitive and valid. Therefore, the use of the quality of life questionnaire can be a useful instrument for the monitorization of hypertensive patients.

Adult↗
PubMed1992

Reconstitution of apomyoglobin with extended biliverdins.

An analysis of the reconstitution of biliverdins with extended conformations and horse heart apomyoglobin was carried out. Biliverdins with the 5Z-syn, 10Z-syn, 15Z-anti and 5Z-anti, 10Z-syn, 15Z-anti conformations, as well as biliverdins with the Z,Z,Z, all-syn conformation recombined with apomyoglobin. In every case the P enantiomers were bound in excess to the M enantiomers, with exception of the 5-syn, 10-syn, 15-anti biliverdin where the M enantiomer bound preferentially to the protein. Biliverdins with an anti conformation at the C-10 meso bridge did not recombine with the protein. It was concluded that the presence of a syn conformation at the C-10 methine conferred to the biliverdin the necessary helicity to fit into the apomyoglobin heme pocket. This regioselectivity is of importance in view of the well known analogy between the ligand domains of myoglobin and the C-phycocyanins.

Animals↗
PubMed1992

Modulation of the hyperdynamic circulation of cirrhotic rats by nitric oxide inhibition.

The effects of NG-monomethyl-L-arginine (L-NMMA), an inhibitor of nitric oxide (NO) biosynthesis on the splanchnic and systemic circulation, were investigated in rats with cirrhosis induced by carbon tetrachloride. Portal hypertension in these rats was accompanied by decreased arterial blood pressure and peripheral vascular resistance as well as by splanchnic vasodilation with increased portal venous inflow and decreased splanchnic resistance. Intravenous bolus administration of L-NMMA (25 mg/kg) significantly increased systemic blood pressure and decreased cardiac output. L-NMMA also significantly increased systemic and splanchnic vascular resistance; whereas blood flow to the stomach, small intestine, colon, pancreas, mesentery, spleen, and kidney was decreased significantly. L-NMMA did not alter the portal pressure or portosystemic shunting in these cirrhotic rats, yet portal vascular resistance increased, suggesting effects on the intrahepatic and collateral circulation. Pretreatment with L-arginine (300 mg/kg) prevented the hemodynamic changes induced by L-NMMA. These findings support the concept that local excess formation of NO contributes to changes in splanchnic circulation associated with portal hypertension in cirrhosis.

Animals↗
PubMed1992

Restriction fragment length polymorphism analysis of HLA-DR- and DQ-linked alleles in multiple sclerosis in Spain.

HLA-DR allele subtypes in multiple sclerosis (MS) individuals in Spain were determined by restriction fragment length polymorphism (RFLP) analysis. The well-established association of DRw15, DQw6, Dw2 alleles and MS susceptibility was confirmed. The strength of its association, however, was relatively weak in our MS population and no involvement with any other DR allele was observed. DQw6 increase correlated with the elevation of the involved DR2 subtype. The hypothesis that MS-associated susceptibility genes may be more closely associated with the DQ than the DR region was not supported by our findings which, on the other hand, could be in concordance with the concept that multiple genes contribute to MS susceptibility.

Alleles↗
PubMed1992

Hepatic, splanchnic and systemic haemodynamic abnormalities in portal hypertension.

Portal hypertension is characterized by a pathological increase in portal venous pressure that leads to the formation of portosystemic collaterals that divert portal blood to the systemic circulation, bypassing the liver. Increased vascular resistance to portal blood flow is the initiating factor in portal hypertension. Increased resistance along the hepatic and portocollateral circulation is in part modifiable by pharmacological agents. An additional factor is splanchnic vasodilatation with increased portal blood inflow, which contributes to the maintenance and aggravation of the portal hypertension. Endogenous vasodilators are thought to be responsible for the splanchnic hyperaemia of portal hypertension. Vasodilatation is also prominent in the stomach and lungs, and plays an important role in the pathophysiology of portal hypertensive gastropathy and of the hepatopulmonary syndrome. The systemic circulation is markedly hyperkinetic, with reduced arterial pressure and peripheral resistance and increased cardiac output. The plasma volume is expanded due to renal sodium retention. The expanded plasma volume enables the increase in cardiac output, and represents another mechanism contributing to the increase in portal pressure.

Blood Flow Velocity↗
PubMed1992

[Utility of high-resonance ultrasonography in the diagnosis of acute appendicitis].

The clinical records and the ultrasound findings of 48 patients studied because of a presumptive diagnosis of acute appendicitis in a one-year period were reviewed. Ultrasound examination was performed using graded compression and high resolution probes when acute appendicitis was suspected and the clinical history or physical examination was unclear. The ultrasound findings were correlated with the clinical course or surgical and pathological findings. This procedure was useful in the diagnosis of acute appendicitis, with 84.6% sensibility and 95.5% specificity. Predictive value for positive results was 95.7% and 84% for negative results. These figures agree with results previously communicated in the literature. It is concluded that high resolution ultrasonography is useful in the differential diagnosis of atypical acute appendicitis.

Abdomen, Acute↗
PubMed1992

[The biological aftereffects of preoperative and palliative percutaneous biliary drainage].

Biological repercussions in 78 patients with malignant obstructive jaundice in whom percutaneous biliary drainage was performed, are reported. In 37 cases drainage was done during operation while 41 were palliative. Biochemistry, proteinogram, hematological studies, renal function and immunology were assessed 15.7 +/- 3.4 days postoperatively and 25.2 +/- 4.7 days in palliative drainage. Results show a significant improvement of all parameters, more important in preoperative drainages especially in those combining percutaneous and internal drainage techniques.

Aged↗
PubMed1992

Pathophysiology of portal hypertension.

Portal hypertension is characterized by a pathologic increase in portal venous pressure that leads to the formation of an extensive network of portosystemic collaterals that divert a large fraction of portal blood to the systemic circulation, bypassing the liver. Experimental models have improved understanding of the pathophysiology of portal hypertension. It is now clear that an increased vascular resistance to portal blood flow is the initial factor responsible for the increase in portal pressure. This resistance is exerted along the hepatic and portal-collateral circulation and is in part modifiable by pharmacologic agents. In a latter stage, an increased portal venous blood inflow, promoted by splanchnic vasodilation, contributes to maintenance and aggravation of portal hypertension. Humoral vasodilatory agents play an important role in the splanchnic vasodilation. Several vasodilators are likely to be involved, including glucagon, prostacyclin, endotoxins, and nitric oxide. The splanchnic vasodilation is associated with a hyperkinetic systemic circulation, with reduced arterial pressure and peripheral resistance and increased cardiac output. The splanchnic circulation is probably the vascular territory in which the vasodilation is more pronounced. Therefore, splanchnic and systemic vasodilation probably share some pathophysiologic events. An expanded plasma volume is observed in all forms of portal hypertension. Expansion of plasma volume is due to renal sodium retention, which has been shown to precede the increase in cardiac output and can be prevented or reversed by sodium restriction and spironolactone. The expanded blood volume represents another mechanism that contributes to further increases in portal pressure.

Animals↗
PubMed1991

The dual oxygenase and peroxidase activities of porphobilinogen oxygenase and horseradish peroxidase: a study using the reaction with phenylhydrazine.

Porphobilinogen oxygenase and horseradish peroxidase show dual oxygenase and peroxidase activities. By treating porphobilinogen oxygenase with phenylhydrazine in the presence of H2O2 both activities were inhibited. When horseradish peroxidase was treated in the same manner only the peroxidase activity was lost while its oxygenase activity toward porphobilinogen remained unchanged. The phenylhydrazine treatment alkylated the prosthetic heme group of porphobilinogen oxygenase and N-phenylheme as well as N-phenylprotoporphyrin IX were isolated from the treated hemoprotein. In horseradish peroxidase the modified heme was mainly 8-hydroxymethylheme. The apoproteins of the alkylated enzymes were isolated and recombined with hemin IX. The oxygenase and peroxidase activities of porphobilinogen oxygenase were entirely recovered in the reconstituted enzyme, while the reconstituted horseradish peroxidase regained 75% of its peroxidase activity.

Chromatography, Gel↗
PubMed1991

Interstitial collagen synthesis by somatic testicular cells in culture.

The synthesis, distribution and types of collagen produced by somatic testicular cells in culture was studied. To investigate whether changes in collagen synthesis correlate with the age of the animal, cultures derived from immature and pubertal rats were established. Immature rats synthesize 40 per cent more collagen than pubertal rats. Both groups of animals synthesize procollagen types I and III. Pro-collagen type I is present in the culture medium as well as in the cell fraction, while type III is only detected in the culture medium. In the transition from immature to pubertal rat, the ratio of procollagen type III to procollagen type I diminishes from 5.7 to 1.7. These results indicate that the synthesis, distribution and molecular characteristics of interstitial collagens changes with the age of the animal. Since, the content of other extracellular matrix components such as proteoglycans and collagen type IV also varies with age, we postulate that the composition of the extracellular matrix in the testes is not constant but changes with sexual development.

Animals↗
PubMed1991

Glucagon hinders the effects of somatostatin on portal hypertension. A study in rats with partial portal vein ligation.

Whether the decrease of portal venous inflow and portal pressure induced by somatostatin is related to the effects of somatostatin in inhibiting the secretion of glucagon and other vasodilatory peptides that are increased in portal hypertension was investigated in the current study. Splanchnic vascular resistance and splanchnic blood flow were determined using radioactive microspheres in rats with portal hypertension caused by partial portal vein ligation. Somatostatin infusion significantly decreased portal pressure (from 13.1 +/- 1.9 to 12.1 +/- 2.2 mm Hg; P less than 0.05). This was associated with a significant decrease in portal venous inflow caused by splanchnic vasoconstriction, as evidenced by increased splanchnic vascular resistance, and with a marked suppression of glucagon secretion. The simultaneous infusion of somatostatin and glucagon (2.8 ng/min, a dose that prevented any decrease in circulating glucagon levels) abolished all the hemodynamic effects of somatostatin. This effect seems to be specific because no hemodynamic changes were noted in portal hypertensive rats receiving only the glucagon infusion.

Animals↗
PubMed1991

Partial deletion of the Rhizobium phaseoli CFN23 symbiotic plasmid implies a concomitant amplification of plasmid DNA sequences.

Rhizobium leguminosarum biovar phaseoli CFN23 loses its ability to nodulate beans at a high frequency because of a deletion of part of its symbiotic (pSym) plasmid (Soberón-Chávez et al., 1986). We report here that at least 80 kb of pSym are deleted upon loss of the symbiotic phenotype; the deletion removes the nitrogenase structural nifHDK and the common nodABC genes. The size of the deleted pSym is not reduced, since it is accompanied by an amplification of other pSym plasmid sequences. This genetic rearrangement is similar to the deletion and amplification of yeast mitochondrial DNA leading to 'petite' mutations.

Blotting, Southern↗
PubMed1991

In vitro ketotifen protection in bronchial hyperreactivity.

There are drugs, such as ketotifen, that inhibit bronchospasm through different mechanisms. In this study, we looked at the changes in the number of sanguineous cells that ketotifen produces, especially in basophil cells, that could explain its prophylactic effects in bronchial hyperreactivity disclosed by exercise, as well as its relation to the variations in basal and total histamine in blood. 22 patients were selected, with a diagnosis of extrinsic bronchial asthma with sensitization against Dermatophagoides, and were compared to a control group. They all underwent an exercise test. Blood samples were taken before and after exercise in order to measure the number of leukocytes and the changes in basal and total histamine. We found that the number of basophils does not increase after exercise in untreated patients, while it does in the control group and in treated patients. This implies that ketotifen stabilizes the basophil cells, hindering their degranulation and the subsequent liberation of mediators that would produce bronchospasm after exercise.

Adolescent↗
PubMed1991

[Experience with the use of immune intravenous immunoglobulin in symptomatic children with human immunodeficiency virus infection].

The Department of Pediatrics of the San Juan City Hospital participated in a collaborative clinical trial, placebo controlled, designed by NICHD with the purpose of determining if the use of gamma immunoglobulin is effective in preventing serious infections in symptomatic children infected with HIV. Of the 372 children randomized, 33 were from San Juan City Hospital. Of the 16 children on placebo, 9 (56%) developed 23 episodes of serious infections and 4 of 15 children on IVIG developed 5 episodes. A total of 24 hospitalizations occurred in the placebo group and six in the IVIG group. The mortality in our center was 12% (4/31). No adverse reactions were registered from the infusions in our center. Intravenous gamma immunoglobulin demonstrated to be effective in preventing bacterial infections and decreasing the number of hospitalizations in a subgroup of children infected with HIV.

Acquired Immunodeficiency Syndrome↗
PubMed1991

[Digital coronary angiography. A new approach in the analysis of the arteriosclerotic plaque].

In order to define the coronary lesions we prospectively performed digital coronary angiographies in 61 patients. The degree of stenosis was measured in 100 lesions by quantitative analysis using densitometric and geometric methods. Two groups of lesions were found by comparing these two methods: Group A, 47 lesions with a poor correspondence in the degree of stenosis between densitometric and geometric analysis (p greater than 0.01; and group B, 53 lesions with a good correspondence. Both groups were correlated with plaque characteristics (unstable or stable), following angiographic criteria. The mean degree of stenosis in all lesions, for densitometric and geometric analysis was 50.04 +/- 21.1% and x 60.66 +/- 22.1% (p less than 0.01), respectively. Unstable plaque was more frequent in group A (80.9%) than in B (17.9%) (p less than 0.0001), and stable plaque was more frequent in B (81.1%) than in A (19.1%) (p less than 0.0001). Less degree of stenosis between A (41.5 +/- 13.2) and B (61.3 +/- 16.05) was found by densitometric analysis (p less than 0.0001) but it was similar by geometric method (60.02 +/- 11.3 in A and 58.6 +/- 14.4 in B) so that the degree of stenosis in unstable plaque was lower by densitometric method. We conclude that densitometric analysis showed poor correlation with geometric analysis in unstable plaques; the difference could be due to the soft component expression of the unstable plaque.

Aged↗
PubMed1991

[Liver cirrhosis and portal hypertension: non-invasive measurement of blood flow in the portal vein with Doppler-duplex].

Doppler-duplex has been widely used to quantify blood flow. Nevertheless, its usefulness in assessing portal vein flow (PVF) has been questioned due to technical problems: vessel cross sectional area measurements, interobserver variability, and PVF changes related to physiological events. This study was aimed to measure PVF in patients with cirrhosis and portal hypertension, to estimate changes in PVF during the respiratory cycle, and to evaluate intraobserver variability of Doppler-duplex technique. Twenty-two patients with liver cirrhosis and portal hypertension and 22 healthy subjects were included. One operator made 6 measurements of portal vein diameter (D) and mean flow velocity in inspiration and aspiration. Area of the vessel (A) and PVF were calculated by a microprocessor. Interobserver variability was estimated for each subject and a mean was determined for each group. In the control group, PVF was 901 +/- 39 ml/min in inspiration and 633 +/- 38 ml/min in aspiration; p < 0.001. In patients with cirrhosis PVF was 1303 +/- 121 ml/min in inspiration and 1003 +/- 96 ml/min in aspiration; p < 0.001. Intraobserver variability was 6.0 +/- 0.6% for D, 12.0 +/- 3% for MV and 18.3 +/- 1.6% for PVF in healthy subjects and 5.3 +/- 0.7% for D, 9.2 +/- 0.9% for MV and 15.2 +/- 1.5% for PVF in patients with cirrhosis and portal hypertension. In conclusion, PVF is significantly increased in cirrhotics. PVF was higher in inspiration than espiration in both groups. The Doppler-duplex method evaluation of PVF has an important intraobserver variability (18.3 +/- 1.6%). Then, changes in PVF less than 20% are not accurately measured by this technique.

Adult↗