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Biomedical subjects

J Hernandez

Publications and source records attributed to J Hernandez.

At least 163 records · Page 9Linked to original sources
PubMed1988

Confirmation of the utility of fine needle aspiration biopsy of the renal allograft.

Allograft immunobiologic theory would predict that analysis of immunocompetent cells infiltrating the renal transplant would be most instructive. Recently a new aspiration biopsy technique has been developed to permit such analysis in patients which can be safely and repetitively performed. The clinical utility of such a technique has been tested utilizing a randomized prospective trial in which an aspirate was obtained every other day from the third post-operative day until discharge. Analysis included examination of adequacy criteria and the capacity of pathologic diagnosis to corroborate clinical diagnosis from coded specimens. Ninety-six aspirates from 21 consenting transplant recipients were obtained and analyzed. In 94 instances a clinical diagnosis could be made; 80 aspirates fulfilled adequacy criteria. We found the technique to be highly sensitive (greater than or equal to 90%) and highly specific (greater than or equal to 90%) for the clinical diagnoses of acute allograft rejection, post-operative acute renal failure, cyclosporine toxicity, and normal function. We conclude that the fine needle aspiration technique is an important adjunct to analysis of clinical renal transplantation and offers a major advantage to the clinical scholar in understanding transplant biology.

Acute Kidney Injury↗
PubMed1988

References ranges and sources of variation for indices of pulsed Doppler flow velocity waveforms from the uteroplacental and fetal circulation.

Variation in indices used to characterize the maximum frequency outline of waveforms obtained from the uteroplacental and fetal circulations by duplex Doppler ultrasound was studied between observers, over a 24-h period and before and after a meal. No significant differences were found. Reference ranges were derived for three indices, the A/B ratio, the resistance index and the pulsatility index, for waveforms from the fetal descending aorta, umbilical artery, and the placental and maternal sides of the uteroplacental circulation. Indices from waveforms from the uteroplacental circulation demonstrated a fall from 16 to 24 weeks gestation with no change thereafter. The umbilical artery indices demonstrated a continuing fall with increasing gestation but the A/B ratio and resistance index from the fetal descending aorta did not change with gestation. The pulsatility index from the aorta demonstrated a gentle rise.

Adult↗
PubMed1988

Microbiological and physico-chemical aspects in dry-salted Spanish ham.

The main microbiological and physico-chemical parameters in dry-salted ham previously selected were determined during the elaboration process. All determinations were performed at 2 levels: surface and internal. The selected microbiological parameters were: total aerobes, halotolerant, lactic acid bacteria, yeasts and hazardous microorganisms. NaCl, nitrate, nitrite, water activity, moisture, pH, temperature and loss of weight were selected for the physico-chemical study. All microbial groups showed a similar behaviour, increasing along the first stages up to the third month of drying, then decreasing to numbers similar to the initial ones. Only the halotolerants maintained fairly high numbers during the last stages. Some groups were almost absent at internal levels. The hazardous bacteria showed different behaviour: whereas the faecal streptococci were fairly abundant during the whole study, coliforms almost disappeared at the final stages.

Animals↗
PubMed1987

Compared efficacy of quinidine, amiodarone and diltiazem on both nomotopic and ectopic automaticity in the rat heart.

The effect of quinidine, amiodarone and diltiazem have been studied on both nomotopic (isolated right atria) and ectopic automaticity (induced by a local injury in the isolated right ventricle) in the rat heart. The efficacy of these three drugs, measured by the corresponding ID25, was diltiazem greater than quinidine greater than amiodarone on atrial rate and amiodarone greater than quinidine greater than diltiazem on ectopic ventricular automaticity. A depression of isolated right atria rate (sinus node function) could be regarded as an adverse effect of the drug tested (toxicity-index). On the other hand, the reduction of ectopic ventricular automaticity by the antiarrhythmic agent is considered as desired effect (effectiveness-index). We conclude that this method might be useful to evaluate the effectiveness-toxicity ratio, as a first experimental step in the development of new antiarrhythmic drugs with a direct action on cardiac tissue.

Amiodarone↗
PubMed1986

Bromocriptine in the treatment of hypertension.

The efficacy of bromocriptine in the treatment of hypertension was assessed in a double-blind placebo controlled cross-over study preceded by a dose titration phase. A diuretic and/or a beta-blocker were administered concomitantly in constant dosage to 11 of the 20 patients who received bromocriptine. A wide range of doses of bromocriptine was tolerated. Side-effects of vomiting and postural hypertension did not occur, possibly due to the gradual increase in the administered doses. Plasma prolactin was not raised in this population of hypertensives. In the dose titration phase (n = 20), a small fall in diastolic but not in systolic blood pressure occurred with bromocriptine, but only with the patient standing and after exercise. In the double-blind phase (n = 9), there was no significant difference in blood pressure between the bromocriptine and placebo treatments. It is concluded that bromocriptine was not effective in lowering blood pressure in the present patients with essential hypertension.

Adult↗
PubMed1986

Sugiura procedure outside Japan. The Mexican experience.

In the last 10 years, we operated on 231 patients with hemorrhagic portal hypertension. Most of these patients had some form of liver disease. We performed various surgical procedures: 47 conventional shunts with H grafts and terminolateral portacaval shunts with arterialization of the portal stump, 139 selective Warren shunts, and in those patients in whom a selective portasystemic shunt could not be performed for technical reasons, esophagogastric devascularization in the form of the Sugiura procedure. Forty-five patients were treated with the Sugiura procedure as a one stage or two stage procedure. A total of 68 emergency and elective operations were performed. The operative mortality rate for the emergency thoracic operation was 41 percent and for the abdominal operation, 42 percent. The overall operative mortality rate in the emergency group was 41 percent. The incidence of recurrent variceal bleeding and encephalopathy was 0 in the surviving patients. The survival rate at 3 year follow-up was 40 percent. The elective group was made up of 24 patients. Eighteen patients had a two stage procedure and 6 patients had a one stage procedure. The operative mortality rate for the abdominal operation was 11 percent, whereas that for the thoracic operation was 7 percent. The operative mortality rate for the one stage procedure was 16 percent. The overall operative mortality rate in the elective group was 10.8 percent. None of these patients had recurrent variceal bleeding and encephalopathy developed in only one (5 percent). The encephalopathy was easily controlled with medical treatment. The 3 year survival rate was 83 percent. We conclude that the Sugiura procedure is an effective procedure to treat hemorrhagic portal hypertension when a selective shunt cannot be performed.

Adolescent↗
PubMed1986

Plasmid expression vector using the lambda late promoter.

A plasmid expression vector called pQTE1 based on the late promoter, pR', and positive control gene Q of bacteriophage lambda has been constructed. This vector has unique cloning sites for placing exogenous DNA under control of pR'. Induction of expression of genes cloned into the pQTE1 plasmid leads to massive overproduction of the gene products. Also, transcription from the pR' promoter on pQTE1 appears to be insensitive to polarity effects.

Bacteriophage lambda↗
PubMed1986

Results of surgical treatment of coarctation of the aorta in the critically ill neonate. Including the influence of pulmonary artery banding.

During a 7 year period, 64 consecutive neonates (less than 30 days of age) underwent surgical repair of coarctation of the aorta. There were no intraoperative deaths, four (6%) postoperative deaths, and seven (12%) late deaths. Improvement in the survival rate in this study can be attributed to improved perioperative care, avoidance of hypothermia during the operation, use of prostaglandin E1 to stabilize the patient's condition before the operation, emergency cardiac catheterization and operations, adequate relief of the aortic obstruction, and appropriate use of pulmonary artery banding. The last of these factors may further reduce the mortality. Banding of the pulmonary artery in patients with complex cardiac lesions associated with a ventricular septal defect has significantly lowered the mortality compared with the mortality of those without pulmonary artery banding. In contrast, the absence of pulmonary artery banding in those with a large ventricular septal defect did not affect the mortality or postoperative ventilator requirements as compared to patients having banding and coarctation repair. One late death was related to complications of the pulmonary artery band.

Aortic Coarctation↗
PubMed1986

The effects of adenosine, ATP and ADP on ventricular automaticity induced by a local injury in the isolated right ventricle of the rat.

The effects of adenosine, adenosine triphosphate (ATP) and adenosine diphosphate (ADP) on ventricular automaticity induced by a local injury have been studied in the isolated right ventricle of the rat. Adenosine in low concentrations (10(-10)--10(-8) M) increased ventricular automaticity but in high concentrations (10(-5)--10(-4) M) decreased it. ATP and ADP decreased consistently ventricular automaticity, ATP being more effective than ADP. Theophylline in a concentration (5 X 10(-4) M) devoid of effect on ventricular automaticity antagonized both the excitatory and the inhibitory effects of adenosine. A high calcium solution (5.4 mM calcium) also prevented both the excitatory and the inhibitory effects of adenosine. The results suggest that adenosine in low concentrations might contribute to ventricular dysrhythmias, and that ATP and ADP as well as high concentrations of adenosine might have antidysrhythmic effects. The effects of adenosine appear to be mediated through calcium-dependent theophylline-sensitive receptors: the high affinity receptor operating the excitatory effect and the low affinity adenosine receptor operating the adenosine inhibitory effect on ventricular automaticity.

Adenosine↗
PubMed1985

Binding characteristics of (-)- and (+)-nicotine to the rat brain P2 fraction.

Saturation studies employing (-)- and (+)-[3H]nicotine indicate that the isomers bind to different very high and high affinity sites since the binding density for (-)-[3H]nicotine is 10 times that for (+)-[3H]nicotine. Both isomers also bind to a low affinity site (KDS = approximately 10(-5) to 10(-4) M). Competition studies employing unlabelled (-)- and (+)-nicotine reveal greater complexities. The isomers also appear to bind to a separate site which enhances binding at the (-)- and (+)-nicotine high affinity sites. (+)-Nicotine is more effective in increasing the binding of (-)-[3H]nicotine at its high affinity site than (-)-nicotine. Further, (+)-nicotine has a greater specificity for enhancing binding than (-)-nicotine in that it enhances (-)-[3H]nicotine binding at lower concentrations and inhibits binding at higher concentrations than (-)-nicotine.

Animals↗
PubMed1985

Immediate and short-term benefit of multilesion coronary angioplasty: influence of degree of revascularization.

The safety and short-term therapeutic benefit of multilesion percutaneous transluminal coronary angioplasty was assessed in 135 patients, 66 of whom had a minimum of 6 months of follow-up study. Primary success, defined as successful dilation of the most critical lesion or all lesions attempted without major in-hospital complications was obtained in 117 (87%) of the 135 patients. Cardiac complications associated with the procedure were uncommon; prolonged angina occurred in 5% and myocardial infarction in 3%; emergency coronary bypass surgery was performed in 4% of the patients. There were no deaths. Complete revascularization was achieved in 46% of the 117 patients with a primary success. Of the 66 patients eligible for 6 month follow-up, 80% had an uncomplicated course and required no further procedures. Clinical improvement by at least one angina functional class was observed in 90% of the patients. Cardiac events such as the need for a second revascularization procedure were significantly more common in patients who had incomplete versus complete revascularization (35 versus 9%; p = 0.018). Repeat coronary angiography performed an average of 5 months after angioplasty revealed restenosis in 18 of 22 symptomatic patients and 3 of 9 asymptomatic patients. Restenosis occurred at the site of a single dilation in 12 patients, at two sites in 8 patients and at three sites in 1 patient. Thus, multilesion coronary angioplasty is an important therapeutic option for selected patients with multivessel disease and can be performed with relatively low risk. Improvement in angina status can be expected even in patients who have incomplete revascularization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Structure-activity relationships of some pyridine, piperidine, and pyrrolidine analogues for enhancing and inhibiting the binding of (+/-)-[3H]nicotine to the rat brain P2 preparation.

Previous studies have shown that (+/-)-[3H]nicotine binds to multiple sites in the rat brain P2 preparation. Using a series of pyridine, piperidine and pyrrolidine analogues, the present studies identified drugs with specificity for a separate up-regulatory site that increases the density of nicotine binding at another site. Of these compounds, (+/-)-2-methylpiperidine was the most specific. Some compounds inhibited without enhancing (+/-)-[3H]nicotine binding, but none bound with the very high affinity exhibited by nicotine and none could be classified as specific in inhibiting binding at a specific site. Structural changes in the 1- and 2-positions of pyridine and piperidine appear to be important for conferring specificity for the up-regulatory site whereas 3-position changes may be important for binding specificity.

Acetylcholine↗
PubMed1985

Possible involvement of epinephrine in the cardiovascular effect of naloxone in humans.

The opioid-receptor antagonist naloxone was administered intravenously in a 0.8-mg bolus to five healthy volunteers, aged 21 to 31, in a double-blind study designed to investigate the effect of endogenous opioids on blood pressure, heart rate, and urinary excretion of catecholamines in healthy adults. Three hours after administration of naloxone there were significant increases in systolic blood pressure (P less than 0.001) and heart rate (P less than 0.05). The amount of epinephrine excreted in urine during the four hours after administration of naloxone or placebo was significantly higher (P less than 0.05) in subjects given naloxone. These effects support the hypothesis that an endogenous opioid system is involved in the regulation of systolic blood pressure and heart rate in healthy adults. The results also indicate that adrenally released epinephrine could mediate the cardiovascular effect of endogenous opioids.

Adult↗