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Biomedical subjects

D Weiss

Publications and source records attributed to D Weiss.

At least 37 records · Page 2Linked to original sources
PubMed1991

Scavenging of superoxide anion by phosphorylethanolamine: studies in human neutrophils and in a cell free system.

On the basis of previous observations, we attempted to characterize the effects of various products of phospholipid hydrolysis on neutrophil (PMN) respiratory burst activity. We studied the effects of phosphorylcholine (PC) and phosphorylethanoline (PE) on superoxide anion production in PMN and in cell free system. We found that PE but not PC inhibited measured superoxide anion, but that this was not due to inhibition of cellular superoxide generation but to scavenging of generated superoxide anion. Further, utilizing a system based upon the photo-oxidation of O-dianisidine sensitized by riboflavin, we were able to determine that the scavenging effect of PE was not superoxide dismutase (SOD)-like but rather a general scavenging or glutathione (GSH)-like effect. These data underscore the importance of identifying the mechanism of inhibition of superoxide generation by putative inhibitors as being due to a direct cellular effect or to a scavenging property.

Cell-Free System↗
PubMed1991

Infectious imaging with indium-111-labeled nonspecific polyclonal human immunoglobulin.

Nonspecific polyclonal immunoglobulin (IgG), prepared from pooled human serum gamma globulin and labeled with 111In has been reported to be equivalent to antigen-specific antibody in the detection of focal infection or inflammation during the first 24 hr after injection. We describe our experience in a Phase II clinical study using 111In-IgG in 15 patients (8 males, 7 females) ranging from 26 to 80 (mean = 50) yr of age with suspected focal infection/inflammation. Pathologic confirmation was obtained in 5/15 cases. A combination of clinical course, laboratory results, and other imaging procedures were used to categorize the other 10 patients. One possible false-negative involved a presumed aspiration pneumonia in a patient with a history of aspiration, bibasilar infiltrates on chest film, and no other identified source of infection. Otherwise, there were 10 confirmed positives, 4 confirmed negatives, and no false-positives. Our findings confirm earlier reports that 111In-IgG may be a superior imaging agent for infection/inflammation with practical advantages over 67Ga-citrate and 111In-labeled leukocytes.

Drug Evaluation↗
PubMed1990

A murine model for B-cell lymphomagenesis in immunocompromised hosts: c-myc-rearranged B-cell lines with a premalignant phenotype.

Activation of c-myc or bcl-2 protooncogene is a common event in B-cell lymphomagenesis. Alone, each is insufficient to produce lymphoma, prompting the search for the additional steps required to complete the malignant phenotype. Among the existing systems of murine or human B-cell neoplasia, no commonly occurring complementary oncogenic activation has been found. This study introduces a new series of murine B-cell lines with a phenotype suggesting that such additional events might not involve intrinsic growth control, but instead host immune mechanisms which normally suppress tumorigenicity of premalignant B-cells. Four murine B-cell lines were isolated from the long-term culture of normal lymphoid tissue bearing a premalignant phenotype. (a) Their phenotype resembled naturally occurring lymphoid tumors of immunocompromised hosts with regard to c-myc activation, aberrant or absent immunoglobulin expression, preferential rearrangement of the lambda light chain locus, and a distinctive pattern of tissue invasion and tumor histology. (b) Their tumorigenicity was strictly dependent on host permissiveness correlated with immunodeficient status: C.B-17-scid greater than BALB/c-nu/nu greater than normal BALB/c much greater than other H-2d strains (NZB x NZW F1, NZB, DBA/2). (c) Host passage selected for malignant variants distinguished by a 10(4)-fold increase in tumorigenicity (as judged by limiting cell dose) and by novel tumorigenicity in nonpermissive syngeneic hosts. These features are analogous to properties of human lymphomas arising in immunocompromised states and, to our knowledge, unique among previously reported murine B-cell lines.

Animals↗
PubMed1990

Benefit and risks of long-term amiodarone therapy for sustained ventricular tachycardia/fibrillation: minimum of three-year follow-up in 145 patients.

Our experience with amiodarone therapy in 145 consecutively referred patients with medically refractory sustained ventricular tachycardia and/or fibrillation treated for at least 3 years was reviewed. Ninety-seven had sustained ventricular tachycardia; the remaining 48 patients were survivors of sudden cardiac death. The patients had a mean of 3.7 +/- 1.4 unsuccessful anti-arrhythmic drug trials before initiation of amiodarone. The initial doses of amiodarone averaged 845 +/- 258 mg for the first 2 weeks and 56% of all patients received a type I antiarrhythmic drug in addition to amiodarone during the initial phase of therapy. The average maintenance dose of amiodarone was 410 +/- 187 mg per day. All patients were followed for a minimum of 3 years or until death or withdrawal from therapy. The maximum follow-up was a period of 8 years. Thus, the average duration of amiodarone therapy was 39 +/- 26 months, representing 472 patient years of therapeutic time on amiodarone. The incidence of deaths either caused by a documented ventricular tachyarrhythmia or presumed to result from an arrhythmic cause was 5.5% in the first year and 3.4% in each of the second and third years of follow-up. During the entire period of follow-up, 56 patients died of all causes (38.6% of the study population). Survival over the follow-up period was influenced significantly by left ventricular function, as judged by either New York Heart Association Functional Class or objective assessment of left ventricular ejection fraction, which was available in 102 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Echocardiographic diagnosis of anomalous origin of left coronary artery].

Cross sectional and M-mode echocardiography is a well-established noninvasive technique in the diagnosis of dilated cardiomyopathy and is essential in the evaluation of its severity and progress. However, in most cases of dilated cardiomyopathy in children, it does not provide data suggestive of the etiology of the disease. In the rare congenital malformation, anomalous origin of the left coronary artery from the pulmonary artery, the echocardiographic techniques may suggest the diagnosis when the left coronary artery cannot be demonstrated to arise from its usual site, the left coronary sinus (as visualized in the short axis of the aortic root). A firm diagnosis can be made if the anomalous origin of the left coronary artery is identified in a cross-sectional view of the main pulmonary artery (left parasternal long axis view of the main pulmonary artery, Fig. 1). This was demonstrated in a 9-year-old girl by coronary and aortic angiography (Fig. 2a, b). Anatomical confirmation was made during corrective surgery 3 months later. The origin of the left coronary artery was at the left posterior aspect of the main pulmonary artery, just proximal to its bifurcation. This is an unusual origin in this anomaly in which the coronary artery has been reported to arise close to the pulmonary valve, but not distal, as in this case.

Child↗
PubMed1989

Culture supernatants of lymphokine-activated killer (LAK) cells contain a high-molecular-weight cytotoxic lymphokine.

Supernatants of human lymphokine-activated killer (LAK) cells grown in vitro were tested for cytotoxic activity against several mouse and human neoplastic cell lines. All LAK preparations tested (14/14) exhibited cytotoxic activity (40-90% killing of the target cells). Sephacryl S-300 Gel filtration experiments indicated that the biological activity of the LAK supernatant is associated with molecular moieties ranging from 800 kDa or more, to less than 10 kDa. The finding of strong cytotoxic activity in LAK supernatants against several tumor lines points to the possibility of employing soluble products of these cells, rather than the living cells themselves, for therapeutic purposes.

Animals↗
PubMed1988

R wave amplitude changes during stress testing in ischemic patients with normal epicardial coronary arteries.

R wave amplitude changes during stress testing were validated in 12 ischemic patients with normal coronary angiograms. The data were compared with findings obtained from 10 patients with clinical and angiographic evidence of coronary arterial disease and 10 normal controls. An abnormal R wave amplitude response occurred in 83.3% of the group with normal coronary angiography, in 80% of the group of patients with clinical and angiographic evidence of coronary arterial disease, and in only 10% of the control group. The similarity of R wave amplitude changes in the first two group suggests that these changes are related to ischemia. If so, then R wave amplitude response to exercise could be of value in the electrocardiographic diagnosis of ischemia in patients with angiographically normal coronary arteries.

Adult↗
PubMed1987

A single bone marrow-derived stromal cell type supports the in vitro growth of early lymphoid and myeloid cells.

A clonal cell line (ALC) derived from murine bone marrow stroma is capable of supporting the continuous, in vitro growth of early lymphoid and myeloid cell populations. The growth-promoting effects of ALC are in part mediated through M-CSF and a pre-B cell growth factor, both of which accumulate in ALC-culture supernatant. To analyze the lymphoid growth factor produced by ALC cells, we derived a pre-B cell indicator line that is dependent on ALC-growth-conditioned medium. Using a combination of biological and biochemical analyses, we have established that the pre-B cell growth factor produced by ALC cells is distinct from IL-1, IL-2, IL-3, and IL-4 (BSF-1), suggesting that the early stages of B-cell development are regulated by a unique stroma-derived growth factor.

Animals↗
PubMed1987

The current evaluation of nonpalpable breast lesions.

To understand the suspected low yield of malignant neoplasms from biopsies guided by needle localization, we reviewed 122 biopsies performed from January 1985 to November 1986 at University Hospital and Arkansas Baptist Medical Center, Little Rock. The positive biopsy rates were 3.5% and 10.6%, respectively. After review of these cases, the following guidelines for biopsy were developed: (1) Do not perform a biopsy on a low-density mass less than 1 cm in diameter. (2) Do not perform a biopsy for asymmetric density or questionable mass. (3) Do not perform a biopsy for secondary signs of malignancy such as skin thickening or asymmetric vasculature. (4) Biopsy is indicated for clustered calcifications, a dominant mass greater than 1 cm in diameter, stellate lesions, or interval change from a previous mammogram. These changes resulted in a positive biopsy rate of 15% for the period from November 1986 through April 1987.

Biopsy, Needle↗
PubMed1987

Torsade de pointes complicating atrioventricular block: report of two cases.

One patient with complete atrioventricular heart block and another with high-degree atrioventricular block, complicated by "torsade de pointes" are presented. Both patients were symptomatic. One had a syncopal episode and the other presented with signs and symptoms of congestive heart failure. The electrocardiographic phenomena of torsade de pointes was repeatedly recorded. No other known predisposing factors for torsade de pointes were identified. The use of right ventricular endocardial pacing suppressed the paroxysms in both patients.

Aged↗
PubMed1987

The value of electrocardiography in patients with right ventricular endocardial pacemakers in the diagnosis of left ventricular hypertrophy: a correlative study of pace electrocardiography and left ventricular mass derived from M-mode echocardiography.

This study evaluated 51 patients with permanent apical right ventricular endocardial pacemakers. The assessment of the diagnostic value of pace electrocardiograms for the determination of left ventricular hypertrophy revealed specificity of 94% and sensitivity of 66%, applying a new parameter: RL1 + SV3 greater than or equal to 30 mm. The application of this criterion in the interpretation of pace electrocardiograms correlated well with values for the left ventricular mass derived from M-mode echocardiograms (r = 0.644, P less than 0.0001).

Aged↗