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Biomedical subjects

J M Luber

Publications and source records attributed to J M Luber.

12 recordsLinked to original sources
PubMed1990

Effect of oxygen free radicals and lipid peroxides on cardiac isoenzymes.

We report here the effect of oxygen free radicals, OFR (superoxide, O2-; hydroxy, OH; t-butylhydroperoxide, H2O2) lipid peroxides (malondialdehyde, MDA), free radical scavengers (superoxide dismutase, catalase, allopurinol) and generator (ferrous chloride) antioxidants (ascorbate, glutathione) spin traps (5,5-dimethyl-1-pyroline-N-oxide, N-t-butyl-L-pheny nitrone) on the cardiac isoenzyme (CK, CK-MB, LDH, LD1) concentrations in the sera of patients with acute myocardial infarction. CK-MB and LD1 were rapidly and completely inactivated by O2- (50 nmol/ml), OH (1 nmol/ml) and MDA (0.6 microM). Butylhydroperoxide (600 microM), and ferrous chloride (200 microM) selectively inhibited CK-MB. The free radical scavengers, antioxidants and spin traps all had minimal effects, and H2O2 had none.

Antioxidants↗
PubMed1989

Intralobular distribution of oleic acid-induced pulmonary edema in the pig. Evaluation by high-resolution CT.

The objective of this study was to elucidate the features of experimentally induced pulmonary edema at the lobular level, using high-resolution CT (HRCT) with pathological correlation. We selected the pig as the experimental animal because the pig has well-defined pulmonary lobules. Twelve Yorkshire pigs were included in this study. Five animals were used for studying normal anatomy of the pig lung. Pulmonary edema was induced by oleic acid infusion in 7 pigs. All computed tomographic (CT) scans were performed on a GE 9800 scanner, using 1.5 mm slice-thickness, 16 cm field of view with 512 X 512 matrix and bone reconstruction algorithm. The animals were killed after CT scans and the lungs were removed, inflated, fixed and dried, and subsequently sliced in sections which corresponded to the CT sections. Using CT images, specimen radiography, and histology, we studied the intralobular distribution of pulmonary edema in selected lobules of each animal. Oleic acid infusion caused multifocal hemorrhagic pulmonary edema within the pulmonary lobule. The distribution was uneven and areas surrounding the lobular bronchi were less involved. HRCT permits evaluation of morphological changes of oleic acid-induced pulmonary edema at the lobular level. The intralobular distribution of the lesions may provide additional information about the mechanism of permeability pulmonary edema.

Animals↗
PubMed1988

High-performance liquid chromatographic method for the direct quantitation of oxy radicals in myocardium and blood by means of 1,3-dimethylthiourea and dimethyl sulfoxide.

A direct, sensitive (50-200 ng), simple and specific high-performance liquid chromatographic (HPLC) method is described for the quantitation of oxy radicals by means of the consumption of dimethyl sulfoxide (DMSO) by the hydroxy radical and dimethylthiourea (DMTU) by hydrogen peroxide. The specific scavengers catalase and L-methionine were used to quantitate hydrogen peroxide and OH, respectively. The DMSO and DMTU peaks were separated and identified by HPLC on a Waters C18 Resolve 10-microns Radial-Pak column with an isocratic mobile phase (5% aqueous methanol) at 2 ml/min with UV detection (DMSO, 214 nm; DMTU, 240 nm). The OH concentrations were extrapolated by a luminol chemiluminescence technique. A linear relationship was obtained for DMTU consumption by hydrogen peroxide in the range 0.25-0.40 mM with a coefficient of variation (C.V.) of 8.8 +/- 2.1% and for DMSO consumption by hydroxy radicals in the range 0.1-3.2 microM OH, with a C.V. of 9.6 +/- 3.6%. The limits of detection for this method were 50 ng of hydrogen peroxide for DMTU and 200 ng of OH for DMSO. Hydrogen peroxide averaged 10.5 +/- 3.6 nmol/ml in blood and 56.4 +/- 5.3 mumol/g wet weight in left ventricular (LV) tissue. The hydroxy radical concentration was 0.1 microM in blood and 0.3 microM in LV tissue.

Animals↗
PubMed1988

Specificity of oxygen radical scavengers and assessment of free radical scavenger efficiency using luminol enhanced chemiluminescence.

The selective scavenging capacities of 19 important oxygen radical scavengers were determined by adding them individually to each of the four oxy radical standards, (superoxide, hydroxy, alkoxy and hydroperoxy, and singlet O2), calculating the percent chemiluminescence inhibited, and extrapolating O2 equivalents neutralized from baseline. The sensitivity (0.01 nm/ml) and selectivity of this method not only allows identification of individual oxygen free radical species but also quantitates the efficiency of free radical scavengers.

Benzofurans↗
PubMed1988

Effect of increasing inspired oxygen concentration on hemodynamics and regional blood flows.

Previous reports suggest that in response to increasing FIO2, peripheral resistance increases, cardiac output falls, and regional blood flow decreases. This study examined the influence of varying FIO2 on pulmonary and systemic vascular resistances (PVR, SVR), cardiac output, ventricular work, and regional blood flows in ten anesthetized Yorkshire white pigs. Each animal served as its own control, and was exposed to varying FIO2 in random order. PCO2 was maintained at 40 +/- 5 torr and body temperature at 38.5 degrees C. Heart rate, systemic arterial pressure, pulmonary artery pressure (PAP), pulmonary capillary wedge pressure, thermodilution cardiac output, and blood flows in the femoral, carotid, renal and superior mesenteric arteries were measured at each FIO2. SVR, PVR, left and right ventricular stroke work (LVSW, RVSW) were calculated. One-way analysis of variance-randomized block design (F-test) showed significant decreases in PAP, PVR, and RVSW with increased FIO2. No change was noted in regional flows, cardiac output, SVR, or LVSW. We conclude that in this animal model administration of oxygen up to an FIO2 of 1.0 had no adverse effect on hemodynamic performance.

Animals↗
PubMed1985

Right ventricular myxoma.

This report describes a patient with right ventricular myxoma in whom two-dimensional echocardiography was the sole means of diagnosis and provided sufficient justification for surgical intervention without further invasive workup. A review of the literature also is presented.

Adult↗
PubMed1984

Sternotomy infection after harvesting of the internal mammary artery.

Use of the internal mammary artery for coronary revascularization does not increase the incidence of postoperative median sternotomy wound infection. When infection does occur in these patients, however, successful treatment is more likely to require more aggressive surgical manipulation, such as the use of vascularized muscle pedicle grafts, to eventually close the sternal defect.

Adult↗
PubMed1983

Repair of double-outlet right ventricle: early and late results.

Fifty-seven patients underwent reparative surgery between 1973 and 1981 for various forms of double-outlet right ventricle. Pulmonic stenosis was present in 35 (61%), 15 (43%) of whom required a valved conduit for repair. Subaortic stenosis was present in six patients (11%). Hospital mortality was 12% (7/57), with three of the deaths among five patients with associated defects of the atrioventricular valves. During a mean follow-up of 3.6 years (range 2 months to 9 years), there have been no late deaths. Repeat cardiac catheterization in 28 of 50 survivors (56%) showed a residual ventricular septal defect (Qp/Qs greater than 1.5) in six patients, residual pulmonic stenosis (gradient greater than 35 mm Hg) in six patients, and subaortic obstruction (gradient greater than 50 mm Hg) in two patients: The indications for reoperation in 12 of 50 survivors was a residual ventricular septal defect in five patients, atrioventricular valve regurgitation in three patients, subaortic or subpulmonic obstruction in three patients, and aortic valve regurgitation in one patient. None of the patients died after repeat surgery. Our results indicate that surgical risk is related to the anatomic complexity of the malformation. Although a good hemodynamic outcome was achieved at initial surgery in the majority of patients, a residual abnormality was present in 24% needing surgery. When present, significant defects can be repaired with low mortality and morbidity.

Adolescent↗
PubMed1980

The use of time-interrelated covariates to predict survival following aortic valve replacement.

One hundred four patients survived isolated aortic valve replacement with the model 1200 prosthesis between 1965 and 1968, with a 12-year survival of 64%. Multiple regression survival analysis was employed in an attempt to determine which of 26 preoperative variables affected late survival and to devise a formula to predict survival for a given individual. The most important variables in the regression equation were right atrial mean pressure, etiology, and sex. The effect of the last two were found to vary with time over the 12-year post-operative period. An extension of the standard regression analysis technique was developed to incorporate time-related cofactors into the model. Based on the multiple regression model, 12-year survival was estimated to range from 92% to 14% for the best and worst combinations, respectively, of the three significant variables. The advantages of the regression method are outlined and the findings of other studies with regard to factors affecting survival after aortic valve replacement are summarized and discussed.

Adult↗