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Biomedical subjects

R L Riley

Publications and source records attributed to R L Riley.

At least 55 records · Page 3Linked to original sources
PubMed1980

Stability of DNA/anti-DNA complexes. II. Salt lability and avidity.

The kinetics of dissociation of antibody-radiolabeled dsDNA (homogeneous PM2 DNA or sonicated dsDNA of m.w. 6 x 10(5)) complexes at 37 degrees C have been examined via three independent radioimmunoassays: the Farr, Millipore Filter, and PEG assays. Two different procedures were used to study the kinetics. Either excess unlabeled DNA or high salt concentrations were employed to induce complex dissociation. Our results suggest that typical SLE sera contain at least two distinct populations of anti-dsDNA antibodies. One population is of rather high avidity and dissociates slowly in the presence of excess DNA or high salt. The other population is of considerably lower avidity and is dissociated more rapidly under these conditions. The results of a double label dissociation kinetics study provide independent evidence supporting this hypothesis.

Animals↗
PubMed1980

Recovery of monkeys after myocardial infarction with ventricular fibrillation. Effects of PGB.

PGBx, a polymeric, stable, free radical derivative of 15-keto-prostaglandin B1, that conserves oxidative phosphorylation in mitochondria under degenerative conditions in vitro, affected survival of male Rhesus monkeys (5-9 kg) anesthetized with pentobarbital and subjected to coronary ligation and induced ventricular fibrillation (VF). In tests performed in sequence with intervening periods for recover, intracardiac injections of norepinephrine (NE), cardiac massage (CM), and electrical defibrillation (EDF) were used to restore cardiac function both in controls and experimental animals, but the latter were injected also with 1 mg/kg PGBx. Recovery was established by maintenance of effective blood pressure without exogenous support. In the control group the cumulative survival for fibrillation episodes of 4, 6, 8, and 12 min was 60, 40, 31, and 25% respectively. In the PGBx-treated group survival for equivalent periods was 100, 93, 93, and 88% respectively. In separate studies, African Green monkeys were subjected to single episodes of VF of either 8 or 12 min. Combined survival was 36% for the controls, 93% for the PGBx-treated animals. Clearly PGBx radically improved cardiac recovery after circulatory arrest due to VF in the presence of acute myocardial infarction. The results also suggest a synergistic action between norepinephrine and PGBx in achieving such recovery.

Animals↗
PubMed1979

Detection of low avidity anti-DNA antibodies in systemic lupus erythematosus.

The binding of sonicated, radiolabeled DNA by systemic lupus erythematosus (SLE) sera was measured by a high sensitivity polyethylene glycol (PEG) precipitation assay. This method is considerably more sensitive than currently used techniques. The results suggest that a significant concentration of low avidity antibodies is present in SLE sera; however, these antibodies are not detected by conventional techniques.

Antibodies, Antinuclear↗
PubMed1978

Airborne spread of measles in a suburban elementary school.

A measles epidemic in a modern suburban elementary school in upstate New York in spring, 1974, is analyzed in terms of a model which provides a basis for apportioning the chance of infection from classmates sharing the same home room, from airborne organisms recirculated by the ventilating system, and from exposure in school buses. The epidemic was notable because of its explosive nature and its occurrence in a school where 97% of the children had been vaccinated. Many had been vaccinated at less than one year of age. The index case was a girl in second grade who produced 28 secondary cases in 14 different classrooms. Organisms recirculated by the ventilating system were strongly implicated. After two subsequent generations, 60 children had been infected, and the epidemic subsided. From estimates of major physical and biologic factors, it was possible to calculate that the index case produced approximately 93 units of airborne infection (quanta) per minute. The epidemic pattern suggested that the secondaries were less infectious by an order of magnitude. The exceptional infectiousness of the index case, inadequate immunization of many of the children, and the high percentage of air recirculated throughout the school, are believed to account for the extent and sharpness of the outbreak.

Air↗
PubMed1978

Effects of lidamidine hydrochloride (WHR-1142A), a novel antidiarrheal agent on the cardiovascular and central nervous systems.

1-(2,6-Dimethylphenyl)-3-methylamidinourea hydrochloride (WHR-1142A, lidamidine hydrochloride) has been reported to be a potent antidiarrheal agent in laboratory animals. This study defines its effects on the cardiovascular and central nervous systems. At doses greater than 1 mg/kg i.v., WHR-1142A reduced cardiac output in the anesthetized dog primarily by depressing heart rate; the blood pressure was slightly elevated due to an increase in peripheral resistance. WHR-1142A was effective in reverting ouabain-induced ventricular arrhythmias to a sinus rhythm. Unlike diphenoxylate, WHR-1142A did not potentiate the CNS depressant effects of hexobarbital or ethanol. WHR-1142A did not block pentetrazole-induced convulsions, electroshock seizures or amphetamine aggregate toxicity. At high doses WHR-1142A caused a general CNS depressant effect was not related to a neuroleptic- or barbiturate-like action.

Amidines↗
PubMed1978

Pharmacological properties of lidamidine hydrochloride (WHR-1142A), a novel antidiarrheal agent.

1-(2',6'-Dimethylphenyl)-3-amidinourea hydrochloride (WHR-1142A, lidamidine hydrochloride), a potent, unique antidiarrheal agent, was tested for other pharmacological properties. It inhibited gastric acid secretion in both 4-h and 22-h pylorus-ligated rats and reduced mortality and gastric ulcer severity in the latter test. WHR-1142A also exhibited local anesthetic activity in the rabbit corneal reflex and guinea pig intradermal wheal tests and reverisbly blocked conduction in isolated frog nerves. Low doses of WHR-1142A increased plasma glucose concentration in fasted mice and rats and prolonged the hyperglycemia in response to a glucose meal. WHR-1142A showed mild diuretic activity but had no anti-inflammatory or antibacterial activity. The acute oral LD50 of WHR-1142A was 260 (208,328) mg/kg in male mice, 267 (212,336) mg/kg in male rats and 160 130,197) mg/kg in female rats.

Amidines↗
PubMed1977

The inhibition of prostaglandin synthetase in vivo by nonsteroidal anti-inflammatory agents.

The effects of two nonsteroidal anti-inflammatory compounds, fenclorac and indomethacin, on arachidonate and prostaglandins (PG) E1- and E2-induced vasodepressor responses were determined in the spontaneously hypertensive male rat. A 0.4 to 2 mg/kg intravenous dose of fenclorac blocked the arachidonate-induced vasodepressor response and had no effect on PGE1- and E2-induced hypotension. Similar responses were observed after indomethacin. These results were indicative of in vivo inhibition of PG synthetase by fenclorac and indomethacin. Administration of propranolol did not alter the arachidonate or PG responses; regitine reduced the arachidonate and PG response, suggesting that alpha-adrengergic receptors in vascular smooth muscle may play a role in the prostaglandin-induced hypotension.

Animals↗
PubMed1977

Ultraviolet air disinfection for protection against influenza.

Three converging lines of evidence support the belief that it may be possible, under appropriate circumstances, to interrupt the airborne transmission of influenza by ultraviolet (UV) air disinfection. These lines of evidence are: (a) that influenza is airborne; (b) that UV irradiation of the upper air of a room can provide safe and effective disinfection of air in the lower part of the room; and (c) that epidemic spread of airborne viral infections in humans can be prevented if the population under consideration remains in the UV-protected environment.

Air↗
PubMed1976

Ultraviolet susceptibility of BCG and virulent tubercle bacilli.

To test the effectiveness of irradiating the upper air of a room with ultraviolet light at reducing the concentration of airborne tubercle bacilli, the susceptibility to the germicidal effects of ultraviolet light, Z, was determined for various mycobacteria. Virulent tubercle bacilli and bacille Calmette-Guérin (BCG) were equally susceptible to ultraviolet radiation, whereas Mycobacterium phlei had 10 times their resistance (Z, approximately one-tenth that for M. tuberculosis). The effectiveness against BCG of upper air ultraviolet irradiation in a room was tested directly by nebulizing BCG into the air of the room and monitoring its rate of disappearance. With one 17-watt fixture operating, the rate of disappearance increased 6-fold; with 2 fixtures operating (46 watts total), the rate of disappearance increased 9-fold. This implies that under steady-state conditions, the concentrations of airborne organisms with ultraviolet light(s) on would have been one-sixth and one-ninth, respectively. The increase in rate of decay of the airborne organisms using 1 fixture was equivalent to 10 air changes per hour, whereas that using 2 fixtures was approximately 25 air changes per hour (range: 18 to 33 air changes per hour). These increments are less than those reported previously for Serratia marcescens, because the Z value for BCG is approximately one-seventh that for serratia. These findings with BCG are believed to be directly applicable to virulent tubercle bacilli.

Air Microbiology↗
PubMed1975

Arterial pressure-flow relations in the awake standing dog.

The transient circulatory changes following paced heart rate increase are reported from 133 trials with 6 unanesthetized dogs with chronically implanted monitoring devices for heart rate, cardiac output, aortic blood pressure, and mean right atrial pressure. In 62 trials with 2 of the dogs, pulmonary artery, and left ventricular end-diastolic pressure, as well as left ventricular dP/dt were also studied. The sequence of changes in pressures and flows is analyzed in terms of probable underlying mechanisms, particularly with respect to the nature of vascular resistances. The rise in aortic pressure and flow during the first 3 s of paced heart rate increase, before arterial stretch receptor reflexes become active, is more consistent with an effective downstream pressure of about 49 mmHg, presumably at the arteriolar level, than with an effective downstream pressure close to 0 mmHg at the right atrial level. In the pulmonary circulation where vascular reflex effects are less prominent, the pattern of pulmonary arterial pressure and flow for the entire 30 s of observation is consistent with an effective downstream pressure of 9 mmHg, presumably at the alveolar or pulmonary arteriolar level, rather than at the level of the left ventricular end-diastolic pressure.

Animals↗
PubMed1975

Mechanisms of enhancement of cardiac output during paced tachycardia in conscious dogs.

The mechanisms of enhancement of cardiac output of unanesthetized dogs from 2.7 to 3.6 l min-1 during paced heart rate increase from 92 to 178 beats min-1 were studied in 92 trials with 5 dogs. This enhancement of cardiac output was accompanied by a 0.6 mm Hg fall in right atrial pressure and a 3.3 mm Hg fall in left ventricular end-diastolic pressure. The results are compatible with the hypothesis that an isolated rise in cardiac function shifts blood from the heart and lungs into the systemic circulation which increases the degree of filling of the peripheral vessels and hence increases mean systemic pressure. We postulate that decompression of both atria reflexly raises the tone of the peripheral vessels while the increase in arterial blood pressure reflexly lowers the tone. Apparently a balance is achieved that results in an elevated mean systemic pressure, displacement of the venous return curve to the right, and an increase in the amount of venous return that matches the enhanced cardiac output.

Animals↗