Biomedical subjects

D Rader

Publications and source records attributed to D Rader.

21 records · Page 2Linked to original sources

PubMed1983

Colonic inhibition of pancreatic and biliary secretion.

The purpose of this study was to determine whether or not nutrients in the colon influence pancreatic and biliary secretion in humans. In six healthy subjects, similar caloric loads (117 cals) of oleic acid, essential amino acids, and glucose in isomolar (280 mosmol/L), similar pH (7.4) solutions were infused into the right colon at 10 ml/min through a colonic tube passed by mouth. A background of submaximal pancreatic and biliary secretion was maintained by continuous intravenous infusion of the octapeptide of cholecystokinin. Biliary and pancreatic secretions were quantitated using the gastroduodenal intubation perfusion technique. Among the three nutrients tested, only oleic acid in the colon decreased pancreatic enzymes and bicarbonate outputs. The mean trypsin output decreased from 26.3 +/- 2.6 kU/h to 12.3 +/- 1.9 kU/h (46% +/- 6% of control), while the lipase output decreased from 62 +/- 6.6 kU/h to 36 +/- 5.6 kU/h (58% +/- 6% of control). Similarly, the output of bicarbonate in the duodenal aspirate decreased from 31 +/- 7.2 mEq/h to 16.3 +/- 3.1 mEq/h (61% +/- 5% of control). Intracolonic perfusion of essential amino acids or glucose had no effect on pancreatic enzymes and bicarbonate secretion. In contrast, all three nutrients in the colon inhibited biliary secretion. The mean output of bilirubin decreased from 56 +/- 6 mg/h to 19 +/- 2 mg/h (35% +/- 5% of control) during intracolonic perfusion of oleic acid. Essential amino acids lowered the output of bilirubin from 54 +/- 12 mg/h to 31 +/- 8.6 mg/h (65% +/- 6% of control), whereas glucose lowered it from 53 +/- 12 mg/h to 22 +/- 4 mg/h (45% +/- 5% of control). This differing response of pancreatic and biliary output to intracolonic perfusion of nutrients suggests differential sensitivity of the pancreas and gallbladder to these inhibitory influences. In malabsorption states, unabsorbed nutrients in the colon may inhibit pancreatic and biliary secretion, further contributing to the loss of nutrients from the gastrointestinal tract.

Adolescent↗

PubMedDate not supplied

Prevention of a first stroke: a review of guidelines and a multidisciplinary consensus statement from the National Stroke Association.

OBJECTIVE: To establish, in a single resource, up-to-date recommendations for primary care physicians regarding prevention strategies for a first stroke. PARTICIPANTS: Members of the National Stroke Association's (NSA's) Stroke Prevention Advisory Board and Cedars-Sinai Health System Department of Health Services Research convened on April 9, 1998, in an open meeting. The conference attendees, selected to participate by the NSA, were recognized experts in neurology (9), cardiology (2), family practice (1), nursing (1), physician assistant practices (1), and health services research (2). EVIDENCE: A literature review was carried out by the Department of Health Services Research, Cedars-Sinai Health System, Los Angeles, Calif, using the MEDLINE database search for 1990 through April 1998 and updated in November 1998. English-language guidelines, statements, meta-analyses, and overviews on prevention of a first stroke were reviewed. CONSENSUS PROCESS: At the meeting, members of the advisory board identified 6 important stroke risk factors (hypertension, myocardial infarction [MI], atrial fibrillation, diabetes mellitus, blood lipids, asymptomatic carotid artery stenosis), and 4 lifestyle factors (cigarette smoking, alcohol use, physical activity, diet). CONCLUSIONS: Several interventions that modify well-documented and treatable cardiovascular and cerebrovascular risk factors can reduce the risk of a first stroke. Good evidence for direct stroke reduction exists for hypertension treatment; using warfarin for patients after MI who have atrial fibrillation, decreased left ventricular ejection fraction, or left ventricular thrombus; using 3-hydroxy-3 methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors for patients after MI; using warfarin for patients with atrial fibrillation and specific risk factors; and performing carotid endarterectomy for patients with stenosis of at least 60%. Observational studies support the role of modifying lifestyle-related risk factors (eg, smoking, alcohol use, physical activity, diet) in stroke prevention. Measures to help patients improve adherence are an important component of a stroke prevention plan.

Alcohol Drinking↗

PubMedDate not supplied

Increased formation of distinct F2 isoprostanes in hypercholesterolemia.

BACKGROUND: F2 isoprostanes are stable, free radical-catalyzed products of arachidonic acid that reflect lipid peroxidation in vivo. METHODS AND RESULTS: Specific assays were developed by use of mass spectrometry for the F2 isoprostanes iPF2alpha-III and iPF2alpha-VI and arachidonic acid (AA). Urinary excretion of the 2 F2 isoprostanes was significantly increased in hypercholesterolemic patients, whereas substrate AA in urine did not differ between the groups. iPF2alpha-III (pmol/mmol creatinine) was elevated (P<0.0005) in homozygous familial hypercholesterolemic (HFH) patients (85+/-5. 5; n=38) compared with age- and sex-matched normocholesterolemic control subjects (58+/-4.2; n=38), as were levels of iPF2alpha-VI (281+/-22 versus 175+/-13; P<0.0005). Serum cholesterol correlated with urinary iPF2alpha-III (r=0.41; P<0.02) and iPF2alpha-VI (r=0. 39; P<0.03) in HFH patients. Urinary excretion of iPF2alpha-III (81+/-10 versus 59+/-4; P<0.05) and iPF2alpha-VI (195+/-18 versus 149+/-20; P<0.05) was also increased in moderately hypercholesterolemic subjects (n=24) compared with their controls. Urinary excretion of iPF2alpha-III and iPF2alpha-VI was correlated (r=0.57; P<0.0001; n=106). LDL iPF2alpha-III levels (ng/mg arachidonate) were elevated (P<0.01) in HFH patients (0.32+/-0.08) compared with controls (0.09+/-0.02). The concentrations of iPF2-III in LDL and urine were significantly correlated (r=0.42; P<0.05) in HFH patients. CONCLUSIONS: Asymptomatic patients with moderate and severe hypercholesterolemia have evidence of oxidant stress in vivo.

Adolescent↗