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Biomedical subjects

A Chen

Publications and source records attributed to A Chen.

At least 433 records · Page 24Linked to original sources
PubMed1986

Tumor size: effect on monoclonal antibody uptake in tumor models.

Studies were performed to determine the effect of tumor size on the incorporation of radiolabeled monoclonal antitumor antibodies (MoAbs) into human tumors growing in nude mice. The colon tumors ranged in size from 0.03-1.6 g, the melanoma from 0.1 to 6.7 g, and the lymphoma from 0.06 to 10.2 g. Indium-111 was primarily used as the radiolabel, however, both 125I and 111In were used as tracers for the MoAb in one experiment. The per g radiopharmaceutical uptake by tumors was inversely proportional to tumor size when tumor specific MoAb was administered. This finding was independent of the radiolabel and was demonstrable when the mice bore two tumors of differing size. When the MoAb was not specific for the tumor, the data were less well defined and a statistically significant correlation with size did not occur. These data are strong evidence for a decrease in per g uptake of labeled tumor specific antibodies as tumors increase in size.

Animals↗
PubMed1986

Regional blood cardioplegic reperfusion during total vented bypass without thoracotomy: a new concept.

This study tests the hypothesis that immediate functional recovery is possible after 2 to 3 hours of regional ischemia by control of the conditions of reperfusion (i.e., total vented bypass) and the composition of the reperfusate (substrate-enriched blood cardioplegic solution) by either central cannulation with thoracotomy or peripheral cannulation without thoracotomy. Total vented bypass could be established successfully in each of 14 experiments (100%) in which the peripheral cannulation method was tested. Regional function (evaluated by ultrasonic crystals in open-chest animals) recovered comparably when substrate-enriched blood cardioplegic solution was given either globally or regionally (46% versus 36%) and total vented bypass was accomplished by either central cannulation or peripheral cannulation technique (i.e., left ventricle decompressed through a transaortic vent catheter, right atrium cannulated through the femoral vein, femoral artery perfusion). In contrast, systolic bulging persisted (-23% control systolic shortening) following normal blood reperfusion in beating, working hearts. Controlled reperfusion (either global or regional) also minimized postischemic edema (81% versus 83% water content, p less than 0.05). The effectiveness of controlled reperfusion (substrate-enriched blood cardioplegic solution during total vented bypass) versus uncontrolled reperfusion (normal blood in beating, working hearts) was assessed also in closed-chest dogs with 3 hours of regional ischemia (i.e., balloon inflation in the left anterior descending coronary artery). Results after controlled reperfusion showed complete recovery of contractility (as shown by echocardiography) at 24 hours, in comparison with only minimal recovery in three of eight dogs receiving uncontrolled reperfusion, and minimal histochemical damage (less than 5% triphenyltetrazolium chloride nonstaining), in comparison with 34% necrosis after uncontrolled reperfusion. These studies suggest that control of the reperfusion conditions and reperfusate composition can be achieved comparably in either the catheterization laboratory or the operating room, and a proposed clinical model for the treatment of patients with acute myocardial infarction is presented for evaluation.

Animals↗
PubMed1985

Decay B--> psi X.

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Journal Article↗
PubMed1985

Effect of etodolac in patients with moderate renal impairment compared with normal subjects.

Twenty subjects (10 with normal renal function and 10 with moderate renal insufficiency) participated in an 8-day study to assess the effects of acute and chronic etodolac dosing on renal function. Subjects and patients were hospitalized and followed a controlled diet (150 mEq sodium, 60 to 80 mEq potassium) during the study. A 3-day drug-free period was followed by 4 days of etodolac, 200 mg b.i.d. Sodium balance and body weight remained unchanged in both groups. Modest reductions in renal function as measured by clearances of inulin and p-aminohippurate occurred acutely only in the patients with renal impairment. Chronic therapy resulted in no decrements in daily creatinine clearance. In an average effective anti-inflammatory dose, etodolac did not produce a sustained effect on renal function in either normal subjects or patients with moderate renal insufficiency.

Acetates↗
PubMed1985

In vivo kinetics of radiolabeled monoclonal anti-CEA antibodies in animal models.

Studies were performed to determine the effect of the radiolabel and circulating carcinoembryonic antigen (CEA) on the pharmacodynamics of monoclonal anti-CEA antibodies (MoAbs). The studies were performed in normal BALB/c mice and in nude mice bearing human colon tumors. Three different tumors were used, each of which produced CEA levels characteristic of that particular tumor's secretory rate. The CEJ-326 MoAb labeled with either 111In or 125I was used in all studies. Circulating CEA induced the removal of 125I and 111In MoAbs from the vascular compartment. Liver concentrations of 111In increased and 125I levels decreased as the CEA secretory rate of the tumor rose. This indicates that circulating CEA complexes form in the vascular compartment which, in an animal model, are removed by the liver and spleen. This results in decreased tumor uptake of the labeled MoAb. The iodinated MoAb complexes are dehalogenated while the 111In is retained by the liver. This dehalogenation may account for the relatively low liver activity observed in radioimmunoimaging with intact radioiodinated anti-CEA MoAbs, provided the CEA complexes are similarly removed from the vascular compartment by the human liver.

Animals↗