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Biomedical subjects

L Alvarez

Publications and source records attributed to L Alvarez.

At least 145 records · Page 8Linked to original sources
PubMed1996

Heparin-coated circuit in coronary surgery. A clinical study.

We performed a randomized study in 101 patients who underwent routine isolated coronary bypass graft surgery. In 50 cases an entire coated Carmeda circuit was used (coated group), and an uncoated circuit in the remaining 51 (uncoated group). A Medtronic Maxima oxygenator and a Biomedicus Biohead were used in all cases. Patients with coated circuits received low systemic heparinization with a heparin loading dose of 200 IU/kg, and 300 IU/kg for the control. Activated coagulation time was maintained at more than 275 s for the coated group versus more than 400 s for the uncoated one. The mean age of patients was 64.1 +/- 9.6 for coated and 63.5 +/- 9.7 for the uncoated group. The number of coronary grafts was 3.1 +/- 0.7 for the coated group and 3.1 +/- 0.1 for the uncoated one. Cross-clamp and bypass times were 53 +/- 14 and 98 +/- 24 min for the coated, versus 57 +/- 15 and 104 +/- 24 for the uncoated, group. Chest drainage was 989.4 +/- 509.5 ml for the coated group versus 1435 +/- 1027 for the uncoated one (P < 0.02). The amount of transfused homologous blood was 723 +/- 597 ml for the coated group versus 1071 +/- 831 ml for the uncoated one (P < 0.03). Postoperative endotracheal intubation time was 12.1 +/- 3.6 h for the coated and 14.6 +/- 4.5 h for the uncoated group (P < 0.05). Bleeding required rethoracotomy in 1/50 of the coated group, and in 4/51 of the uncoated one. Hospital mortality was 1/50 in the coated, and 4/51 in the uncoated, group. In our preliminary experience, heparin coating of an extracorporeal circuit reduces post-operative blood loss and blood transfusions in routine coronary bypass operations.

Aged↗
PubMed1996

Bioactive polyacetylenes from Bidens pilosa.

From the methanolic extract of the whole plants of Bidens pilosa the new beta-D-glucopyranosyloxy-3-hydroxy-6(E)-tetradecen-8, 10,12-triyne besides a known polyine has been isolated and identified mainly by IR and NMR methods. The new compound showed overgrowing action against normal and transformed human cell lines in culture.

Alkynes↗
PubMed1996

Maxillary growth in children after early facial bipartition.

Facial osteotomies performed in young children are frequently associated with growth deficiencies, especially at the middle third of the face. This problem may be more severe when the initial deformity is associated with alveolar and palatal clefts. Orbital hypertelorism is a major congenital malformation requiring early correction. The resection of the ethmoid tissues located between the orbit and the medialization of the orbital skeleton through the intracranial approach modifies the exaggerated interorbital distance but does not correct the vertical shortness at the midline of the face. Also this procedure interferes with the sagittal growth of the maxilla possibly resulting from the horizontal osteotomy across the maxillae. The medial rotation of the two halves of the face performed by the intracranial approach or the subcranial approach simultaneously corrects the orbital hypertelorism and elongates the nose and the central segment of the face. Our experience with this procedure in infants and young children is analyzed. A series of nine patients with orbital hypertelorism associated with median and paramedian clefts underwent correction by hemifacial rotation. All patients were monitored from 6 to 10 years (mean, 7 years) and demonstrated normal sagittal growth of the maxillae.

Cephalometry↗
PubMed1996

Hepatitis C virus RNA quantification in right and left lobes of the liver in patients with chronic hepatitis C.

Quantification of hepatitis C virus RNA in liver tissue is likely to be useful in the study of the natural history, pathogenesis, progression and treatment of hepatitis C virus-associated liver disease. Quantitative measurements of hepatitis C virus RNA in liver biopsy samples using the branched DNA (bDNA) signal amplification assay were carried out. The aims of this study were threefold: first, to assess the level of hepatitis C virus RNA in biopsy samples from the right and left lobes of the liver; second, to evaluate the correlation between hepatitis C virus RNA levels in serum and liver; and third, to investigate the relationship between serum and liver hepatitis C virus RNA levels and the severity of hepatic histology in non-cirrhotic patients with chronic hepatitis C. There was a strong correlation (r = 0.92, P < 0.01) between hepatitis C virus RNA levels in the right and left lobes of the liver as well as a strong correlation between hepatitis C virus RNA levels in liver and serum (r = 0.82, P < 0.01). However, there was no significant correlation between the severity of hepatic histology and levels of hepatitis C virus RNA in serum and liver among patients with chronic active hepatitis classified according to Knodell's hepatic activity index (KI). Our results indicate that hepatitis C virus RNA quantification from a single liver biopsy is representative of both lobes in patients with chronic hepatitis, and suggest that serum hepatitis C virus RNA levels are a meaningful reflection of hepatitis C virus RNA levels in the liver.

Adult↗
PubMed1996

Preoperative clinical, EEG, and imaging findings do not predict seizure outcome following temporal lobectomy in childhood.

Although certain clinical, electroencephalographic (EEG), magnetic resonance imaging (MRI), and pathologic findings in adults with intractable temporal lobe epilepsy predict seizure outcome following temporal lobectomy, predictors of seizure outcome have not been studied systematically in pediatric temporal lobectomy series. We retrospectively analyzed preoperative clinical, EEG, and neuroimaging findings with reference to seizure outcome (seizure free or non-seizure free) in 33 children (mean age, 9.3 years) who underwent tailored temporal lobe resections for intractable temporal lobe epilepsy. Trends were apparent with (1) younger age at seizure onset, younger age at surgery, shorter duration of epilepsy, localized unilateral temporal lesions on MRI, and right-sided surgery more frequently associated with a seizure-free outcome, and (2) significant prior history, daily preoperative seizures, generalized motor seizures, mental retardation, and localized unilateral temporal epileptiform EEG activity more frequently associated with a non-seizure-free outcome. However, none of these findings, alone or in combination, correlated with postoperative seizure status at a statistically significant level. Submitting the four variables generally considered to be most predictive of favorable outcome (ie, normal intelligence, unilateral ictal and interictal EEG discharges, and focal temporal MRI lesion) to a multiple-cutoff procedure did not predict seizure freedom. Our data indicate that predictors of outcome of temporal lobectomy in adults may not apply in children, perhaps due to inherent neurobiologic differences in the etiology and expression of temporal lobe epilepsy, and should therefore not be used as sole determinants of surgical candidacy in children.

Adolescent↗
PubMed1996

[Pneumopericardium: a race against time! Case report and literature review].

An 81-year-old woman without any known previous disease was admitted for epigastralgia, nausea, vomiting and anorexia since 15 days. The investigations disclosed a pneumopericardium which was caused by the perforation of a gastric ulcer, situated on the collar of an hiatal hernia. A pericardial drainage and a suture of the ulcer were performed, but the patient could not be saved. Despite an optimal treatment composed of pericardial drainage, specific surgery and intensive care, the mortality rate of pneumopericardium is still around 50% proving the severity of this illness.

Aged↗
PubMed1996

Low sample volume causes differentiation in human rhabdomyosarcoma cell line RD subjected to electroporation.

Gene transfection has been accomplished with a variety of techniques such as DEAE dextran, calcium phosphate coprecipitation, protoplast fusion, liposomes, microinjection and recombinant bacteriophages. However, transfection by electroporation, consisting of the reversible permeabilization of cell membranes after exposure to a pulsed electric field, has been shown to be the most rapid, simple and efficient method for the stable incorporation of genes in different cell lines. We studied rhabdomyosarcoma cells subjected to electroporation in two different vol. [400 microliters (group 1) and 150 microliters (group 2] of 140 mM NaCl/15 mM Hepes buffer, pH 7.2) and evaluated the effects of electroporation volume on growth and differentiation. Low sample volumes induced a terminal process of morphological and ultrastructural myogenic differentiation in rhabdomyosarcoma cells, which concluded with cell death. Our results suggest that in electroporation low sample vol. of rhabdomyosarcoma cells induced morphological and phenotypic differentiation, with increased expression of desmin, alpha-actinin and tropomyosin.

Actinin↗
PubMed1995

Discriminative value of biochemical markers of bone turnover in assessing the activity of Paget's disease.

Clinical biochemical markers of bone turnover are usually increased in Paget's disease. However, the analysis of "new" markers, such as serum bone alkaline phosphatase (BAP), carboxy-terminal propeptide of type I procollagen (PICP), tartrate-resistant acid phosphatase (TRAP), telopeptide carboxy-terminal propeptide of type I collagen (ICTP), and urinary pyridinoline (PYR) and deoxipyridinoline (D-PYR), may improve the diagnostic efficacy and the evaluation of Paget's disease compared with conventional markers, such as serum total alkaline phosphatase (TAP) and urinary hydroxyproline (HYP). To evaluate the diagnostic accuracy and the changes of biochemical markers of bone turnover according to Paget's disease activity, we measured the levels of all these markers in three groups of pagetic patients classified according to their serum TAP activity: G-I, patients with serum TAP lower than 250 U/l (upper limit) (n = 15); G-II, patients with serum TAP between 251 and 500 U/l (n = 18); and G-III, patients with serum TAP greater than 501 U/l (n = 26). Serum TAP and BAP showed the highest diagnostic accuracy among the markers of bone formation with a sensitivity of 78% and 84%, respectively, when the specificity was 100%. Urinary PYR was the most sensitive marker of bone resorption. Also, urinary PYR showed the highest proportion of increased values in pagetic patients (73%) compared with urinary HYP (64%), urinary D-PYR (60%), serum ICTP (41%), or serum TRAP (39%). In pagetic patients with normal serum TAP activity (G-I), serum BAP concentration was increased in 60% of patients, and urinary PYR was increased in 40% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid Phosphatase↗
PubMed1995

Expression of interleukin 8 and CD54 by human gastric epithelium after Helicobacter pylori infection in vitro.

BACKGROUND/AIMS: Helicobacter pylori is associated with neutrophil infiltrates, although the mechanism of their recruitment is only partially defined. The aim of the study was to determine if Kato III, a human gastric epithelial cell line, expressed cytokines and the intercellular adhesion molecule 1 (ICAM-1), which could contribute to the initiation of inflammation during infection with H. pylori. METHODS: Kato III cells were stimulated with H. pylori and were examined for evidence of infection, cytokine production, and the expression of ICAM-1. RESULTS: The expression of interleukin 8 messenger RNA and immunoreactive protein by Kato III cells was significantly increased over constitutive levels within 3 hours of infection with H. pylori. Infected Kato III supernatants activated neutrophils as evidenced by increased CD11b/CD18 and decreased L-selectin that could be blocked by anti-interleukin 8. In contrast, Campylobacter jejuni, lipopolysaccharide, killed H. pylori, and supernatants from cultures of H. pylori did not increase interleukin 8. Interleukins 2 and 6; interferons alfa, beta, and gamma; and tumor necrosis factor were not produced by resting or H. pylori-stimulated Kato III cells. In addition to producing interleukin 8, Kato III constitutively expressed surface ICAM-1, which acts as an intercellular adhesion molecule for neutrophils. CONCLUSIONS: Our results indicate that H. pylori stimulates the gastric epithelium to initiate inflammation and neutrophil recruitment and activation.

Base Sequence↗
PubMed1995

Electrophysiologic effects of procainamide, mexiletine, and amiodarone on the transplanted heart. Experimental study.

The effects of procainamide, mexiletine, and amiodarone on automaticity, conduction, and refractoriness were studied in a model of heterotopic heart transplantation in dogs that combined an innervated heart (recipient) and a denervated transplanted heart (donor). After the surgical procedure, 500 mg procainamide (n = 13), 200 mg plus 0.1 mg/kg per minute mexiletine (n = 10), or 150 mg amiodarone (n = 10) was administered intravenously. During a baseline period and after drug administration, each heart was assessed for atrioventricular interval; cycle length; sinoatrial conduction time; atrioventricular node anterograde and retrograde block points; atrioventricular node and ventricular antegrade effective refractory periods; PR, QRS, and QT intervals on electrocardiogram; systemic arterial, pulmonary arterial, central venous, and pulmonary capillary wedge pressures; and cardiac output. In recipients, procainamide reduced cardiac output, depressed sinus automaticity, slowed conduction time without affecting the QRS interval, and prolonged the nodal and ventricular refractoriness; in donor hearts, it depressed automaticity and prolonged nodal refractoriness, but did not modify conduction or ventricular refractoriness. Mexiletine only moderately depressed sinus automaticity in recipient hearts; it did not affect the other parameters either in recipient or transplanted hearts, nor did it alter the hemodynamic situation. Amiodarone produced hypotension, reduced cardiac output, and prolonged all the electrophysiologic intervals except the QRS interval in recipient hearts. These changes were even more pronounced in the transplanted hearts and led to extreme sinus bradycardia in four cases. Of these three drugs, mexiletine appears to be the safest should treatment for arrhythmias be necessary in transplant recipients.

Amiodarone↗
PubMed1995

Patellar tendon avulsion after total knee arthroplasty. A new technique.

Patellar tendon avulsion is a rare complication of total knee arthroplasty. An easy surgical technique that involves suturing the tendon into a groove carved in the tibial tubercle and tension band wiring is described. Two cases are presented, with an average follow-up period of 21 months. Good clinical results were obtained in each case. No postoperative complications occurred.

Aged↗
PubMed1995

Articular aspergillosis: case report.

We present an unusual case of osteomyelitis of the tibia and septic arthritis of the knee caused by Aspergillus fumigatus in a renal transplant recipient. Although the characteristic joint involvement was present, the synovial fluid was initially sterile and contained numerous pyrophosphate crystals.

Adult↗