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Biomedical subjects

G B Jacob

Publications and source records attributed to G B Jacob.

5 recordsLinked to original sources
PubMed2001

Inhibition of thrombin by iopromide in vitro.

Iopromide is a nonionic, iodinated, monomeric, radiographic contrast agent used in various indications, including coronary angiography and visceral and peripheral arteriography. Nonionic contrast media have been postulated to increase thrombogenicity when compared with ionic contrast media. The goal of this study was to characterize the interaction of iopromide with thrombin, specifically to determine the rate, extent, specificity, and reversibility of the thrombin inhibition by iopromide, the integrity of the thrombin-iopromide complex, and the inhibitory potency of iopromide using a validated assay methodology. Iopromide was mixed with purified thrombin or pooled serum from healthy male and female donors. The final concentrations of iopromide in the presence of estimated physiologic concentrations of thrombin (1 nmol/L) were 0-184 mmol/L. After incubation for defined time intervals, the activity of thrombin was determined by adding substrate and measuring the absorbance of the generated chromophores at 405 nm. The possible inhibition of the protease trypsin by iopromide was investigated to evaluate the specificity of thrombin inhibition by iopromide. Iopromide was compared with Thromstop, a known thrombin inhibitor, to assess the relative potency of iopromide. The inhibition of thrombin by iopromide was immediate, rapidly reversible, and proportionate to the iopromide concentrations. The minimum inhibitory concentration of iopromide was 50 mmol/L. At the highest iopromide concentration tested, 184 mmol/L, the mean inhibition of thrombin activity was 44.5%. The mean concentration of iopromide associated with a 50% inhibition was 206 mmol/L. The inhibitory potency of iopromide was 4 x 10(6) times smaller than that of Thromstop. The inhibition of thrombin by iopromide is specific, because trypsin was not inhibited by iopromide. The results indicate that in vitro iopromide at clinically relevant concentrations partially inhibits thrombin activity. However, the in vitro model used does not consider other factors that may be relevant for the overall coagulation response in vivo.

Adult↗
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↗
PubMed1978

Hepatitis B surface antigen in human tears.

The incidence of hepatitis B virus infection has been increasing every year in the United States, particularly among medical personnel. Only half of these cases are associated with exposure to blood or blood products. Respiratory, fecal-oral, and venereal methods of transmission of hepatitis B virus infection are supported by epidemiological evidence and by the demonstration of hepatitis B surface (HBsAg) antigen in several body secretions. In this investigation, tears were collected from patients whose serum was positive for HBsAg. These tears were tested for the same antigen, which was found to be present in half the cases. There is a risk of transferring hepatitis B virus infection by tonometers or soft contact lenses contaminated by HBsAg.

Adolescent↗
PubMed1976

Pharmacokinetics of cefamandole in the presence of renal failure in patients undergoing hemodialysis.

The pharmacology of cefamandole in seven patients with stable renal insufficiency and in eight patients undergoing hemodialysis was determined. All patients had creatinine clearances less than 5 ml/min. The half-life of cefamandole in those patients with stable chronic renal failure was 7.7 +/- 2.2 h. The mean venous level 1 h after intravenous injection of a 1-g dose was 85.3 +/- 32.0 mug/ml. The mean venous half-life of cefamandole during hemodialysis was 6.1 h. The venous serum level after 5.5 of hemodialysis was 50.4 +/- 20.8 mug/ml. The mean coefficient of extraction was 0.155, and the mean clearance was 34.7 ml/min. The time interval between doses of cefamandole administered intravenously should be lengthened to 24 h in the presence of stable renal failure. No major change in dosage schedule is necessary for patients undergoing dialysis.

Adult↗