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Biomedical subjects

J Hopkins

Publications and source records attributed to J Hopkins.

At least 163 records · Page 9Linked to original sources
PubMed1986

Monoclonal antibodies to sheep lymphocytes. I. Identification of MHC class II molecules on lymphoid tissue and changes in the level of class II expression on lymph-borne cells following antigen stimulation in vivo.

A rat monoclonal antibody is described that recognizes sheep MHC Class II antigen and appears to recognize a determinant that is non-polymorphic. This antibody precipitates polypeptides of apparent molecular weight 33,000 and 28,000/29,000 (under non-reducing conditions). The binding of this antibody was inhibited by an anti-human DP, DQ, DR beta-chain monoclonal (DA6.231) and its reactivity on murine cells suggests specificity for the I-E gene product. Using this antibody we have studied the distribution of Class II molecules in sheep and also the variations in Class II expression by cells in both peripheral and efferent lymph, produced as a result of in vivo antigen inoculation.

Animals↗
PubMed1985

Persistent expression of Ia antigen and viral genome in visna-maedi virus-induced inflammatory cells. Possible role of lentivirus-induced interferon.

In this study we investigated the pathogenesis of the lymphoproliferative response in the chronic-active visna maedi virus-induced inflammatory lesions. Viral RNA expression was confined to macrophages, but only in tissues showing inflammatory lesions. A persistent and high level of Ia antigen expression was seen in macrophage-like cells in the inflammatory lesions, and the amounts of viral RNA and Ia expression were closely correlated. A small subpopulation of macrophages contained both viral RNA and Ia antigen, and these were found in greatest number in the lung. In vitro experiments showed that a lentivirus-induced interferon (LV-IFN) could induce Ia antigens in normal sheep spleen and lymph node cells as well as in a transformed sheep macrophage cell line. Ia antigen expression in macrophages was transient in the absence of a continuing IFN stimulus and persisted for at least 2 wk in the presence of LV-IFN. LV-IFN also restricted viral replication in macrophages. It is suggested that LV-IFN induced by the inflammatory cells in visna-maedi lesions may induce Ia antigen expression in macrophages, thereby indirectly causing the lymphoproliferative response and restricted virus replication.

Animals↗
PubMed1985

Hemodynamic and metabolic effects of diltiazem during coronary sinus pacing with particular reference to left ventricular ejection fraction.

To determine the systemic and coronary hemodynamic effects of diltiazem at rest and during pacing, 14 patients with stable angina pectoris undergoing coronary angiography were studied before and after 0.165 mg/kg (n = 7) and 0.25 mg/kg (n = 7) of intravenously administered diltiazem. Hemodynamic variables, metabolic measurements and left ventricular (LV) ejection fraction (EF) were obtained at rest and during coronary sinus (CS) pacing before and during diltiazem administration. Lactate production during control pacing turned into extraction after diltiazem (p less than 0.05). At rest, systemic resistance was reduced by 21% (p greater than 0.01) and mean arterial pressure by 12% (p less than 0.01); cardiac index increased from 2.4 +/- 0.4 to 2.6 +/- 0.4 liters/min/m2 (p less than 0.01), with no significant change in heart rate. The mean pulmonary artery pressure increased from 17 +/- 2 to 19 +/- 3 mm Hg (p less than 0.01), but other hemodynamic variables were not affected. Diltiazem given during pacing reduced the mean aortic pressure (from 112 +/- 15 to 104 +/- 15 mm Hg, p less than 0.05), but other hemodynamic variables were not affected significantly. LVEF decreased 16%, from 0.63 +/- 0.9 to 0.53 +/- 0.8 with CS pacing (p less than 0.01); when the pacing was performed after diltiazem administration the 8% decrease in LVEF from 0.64 +/- 0.09 to 0.59 +/- 13 was less marked (p less than 0.01). Diltiazem had no significant effect on LVEF at rest. The overall data suggest that the ischemic manifestations of CS pacing are attenuated by diltiazem in doses of the drug that exert no significant depressant effect on LV function in patients with coronary artery disease.

Adult↗
PubMed1985

Hemodynamic effects of intravenous flecainide relative to the level of ventricular function in patients with coronary artery disease.

Flecainide, a new antiarrhythmic agent with poorly defined hemodynamic actions, was studied in 22 patients with coronary artery disease. Intravenous infusions of 1 mg/kg and 2 mg/kg resulted in respective increases in right atrial pressure (12%, p less than 0.05; 15%, p less than 0.01), mean pulmonary artery pressure (27%, p less than 0.01; 28%, p less than 0.01), and pulmonary capillary wedge pressure (44%, p less than 0.05; 33%, p less than 0.01). Cardiac index decreased 8% (p less than 0.05) after 1 mg/kg flecainide and 12% (p less than 0.05) after the 2 mg/kg dose. The mean left ventricular ejection fraction decreased by 15% (p less than 0.01) and 16% (p less than 0.01), respectively, 10 minutes after 1 mg/kg and 2 mg/kg of flecainide. Minimal increases in the heart rate (less than 5%) and no significant change in arterial pressure occurred 5 to 10 minutes after flecainide and were associated with borderline and variable increases in pulmonary and systemic vascular resistances. Flecainide diluent did not induce changes in pulmonary capillary wedge pressure or left ventricular ejection fraction. Thus, flecainide exerts a moderate but significant negative inotropic effect which may be clinically significant in patients with severely compromised ventricular function.

Adult↗
PubMed1984

Superiority of supine bicycle over isometric handgrip exercise in the assessment of ischemic heart disease: an evaluation of left ventricular ejection fraction response using radionuclide angiography.

Left ventricular ejection fraction (LVEF) response to supine bicycle and isometric handgrip exercise was evaluated in 15 patients with documented coronary artery disease (CAD) and stress-induced ischemia using radionuclide angiography. For purposes of analysis, the patients were divided into two groups: group I (n = 7) with single-vessel disease and group II (n = 8) with multiple-vessel disease including 3 with left main artery disease. The studies were repeated 18 days later at similar external workloads to assess reproducibility of both tests. LVEF response to bicycle exercise was different for the two groups. The change in LVEF from rest to peak exercise was +0.04 +/- 0.02 for group I and -0.07 +/- 0.04 for group II (p less than .001). LVEP response to isometric handgrip exercise was not different between the two groups. The change from rest to end of handgrip exercise was -0.02 + 0.02 for group I and -0.05 +/- 0.02 for group II. The reproducibility of LVEF response to bicycle exercise at similar workloads on day 1 and day 19 was good (r = 0.85) while it was poor for isometric handgrip testing (r = 0.67). Our data demonstrate that radionuclide angiographic measurement of LVEF response to supine bicycle exercise testing is superior to LVEF response to isometric handgrip testing in the evaluation of patients with CAD.

Adult↗
PubMed1984

Giant pseudopolyps in granulomatous colitis. Report of a case.

A case of giant localized pseudopolyp causing partial large-bowel obstruction and occurring in granulomatous colitis is reported. This represented the first manifestation of the patient's disease. The role of surgery in certain patients is discussed.

Colonic Polyps↗
PubMed1984

Comparative effects of oral acebutolol and propranolol at rest and during exercise in ischemic heart disease: double-blind placebo crossover study utilizing radionuclide ventriculography.

Acebutolol is a new investigational beta-antagonist which has intrinsic sympathomimetic and cardioselective properties. In this study its effects on the ischemic consequences following supine bicycle exercise were compared to those of propranolol in 16 patients with chronic stable coronary artery disease (CAD) using a double-blind placebo crossover protocol and equilibrium radionuclide ventriculography. In eight patients (group I), the left ventricular ejection fraction (LVEF) at peak exercise fell under control conditions. During chronic acebutolol therapy (400 mg thrice daily), the exercise-induced LVEF (means +/- 1 SD) was significantly higher (37.1 +/- 15.5% versus 42.2 +/- 14.3%; p less than 0.05). The corresponding values during placebo and during propranolol (80 mg thrice daily) were 39.2 +/- 12.3% versus 43.4 +/- 14.8% (p = 0.07). In eight patients (group II) in whom supine bicycle exercise produced increases in LVEF, both acebutolol (58.8 +/- 5.4% versus 53.8 +/- 4.4%) and propranolol (57.8 +/- 5.7% versus 54.1 +/- 4.9%) attenuated the increases. In neither group was the resting LVEF reduced by acebutolol or propranolol. The data show that acebutolol and propranolol are approximately equipotent in minimizing the radionuclide left ventriculographic manifestations of myocardial ischemia induced by supine bicycle exercise.

Acebutolol↗
PubMed1984

A phase II study of dibromodulcitol (DBD) in stage IV melanoma.

Twenty-four patients were evaluated in a non-randomized study to assess the effectiveness of dibromodulcitol (DBD) in Stage IV melanoma. Patients received 100 mg/m2 of DBD orally for 35 days. The dose was escalated to 130 mg/m2 and then to 160 mg/m2 if no significant hematologic toxicity occurred. There were no objective responses, including six patients who had had no prior chemotherapy. Five patients (21%) remained stable. Median survival was 151 days. Survival favored females, nonvisceral involvement pretherapy, and patients with a disease-free interval (DFI) of greater than 1 year. None of these advantages was statistically significant. Toxicity was predominantly hematologic, but nausea, vomiting, shortness of breath, and diarrhea were also seen. Oral DBD, using this dose and schedule, does not appear efficacious in advanced disseminated melanoma.

Drug Administration Schedule↗
PubMed1984

An interdisciplinary teaching program in geriatrics for physician's assistants.

An interdisciplinary curriculum committee within the Division of Family Medicine, Stanford University Medical Center, developed and taught a beginning course in clinical geriatrics for medical students and student physician's assistants, physical therapists, and nurse practitioners. Through a series of Saturday classes held in community facilities serving seniors, physician's assistant students had the opportunity to learn clinical geriatrics from a faculty team including a physician's assistant, physician, nurse, physical therapist, social worker, gerontologist, and health educator. Local seniors served as consumer consultants and models of health and vigor. This interdisciplinary approach was modeled by the faculty to demonstrate the need for a team approach to deliver quality care to seniors. In this well-received course, the role of the physician's assistant in health care was made evident to their future physician employers and physical therapy co-workers through faculty modeling as well as through informal contacts and patient conferences. Older people constitute a growing and increasingly medically underserved population. Team training may serve to stimulate physician's assistant students to include geriatrics in their career plans while educating their future physician employers about their role.

Curriculum↗
PubMed1984

Effects of furosemide on the plasma and urinary concentrations and the excretion of fentanyl: model for the study of drug interaction in the horse.

The effects of furosemide (0.55 mg/kg IV) on the plasma and urinary fentanyl (PFE UFE) concentrations were studied during steady-state conditions. The PFE during the steady-state period was 0.31 +/- 0.027 ng/ml, with no significant changes occurring, even though the rate of excretion of fentanyl (EX) increased during the 1st hour from 112.0 +/- 21.6 to 534.5 +/- 82.9 ng/minute. The EX returned to control levels within 3 hours, as did the UFE. The injection of furosemide increased glomerular filtration rate from 1.97 +/- 0.21 to 3.81 +/- 0.75 ml/kg/min. The fractional reabsorption decreased from a control of 70.3 +/- 6.2% to 25.2 +/- 2.3% during the 1st hour, returning to control levels at 3 hours after furosemide was given. The total body clearance of fentanyl increased slightly during the peak period of diuresis. The return of EX, fractional reabsorption, UFE, and clearance of endogenous creatinine to control levels occurred before the return of urine specific gravity, indicating the ability of the kidney to concentrate fentanyl before its water concentrating capacity had returned.

Animals↗