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Biomedical subjects

J Young

Publications and source records attributed to J Young.

At least 469 records · Page 26Linked to original sources
PubMed1983

Pharmacokinetics and tolerance of a 24-h infusion of cefotetan disodium (with and without loading dose) in normal Caucasian volunteers.

Cefotetan disodium has been given by zero order intravenous infusion at 75.8 mg/h to four healthy male volunteers over a 24-h period. Plasma concentrations rose until by 12 hs a mean steady state value of 37.5 mg/l was attained. In an additional four volunteers a loading dose of 0.5 g cefotetan was given immediately prior to a similar infusion. In these subjects concentrations in excess of the final steady-state value of 36.2 mg/l were achieved immediately and concentrations never fell below this value for the entire 24-h period of the study. The dose was well tolerated with the exception of an incidence of diarrhoea (2/8 mild and 1/8 severe). The pharmacokinetic findings are in good agreement with theoretical predictions based on single intravenous bolus doses of cefotetan and suggest that a loading dose, followed by an infusion would be suitable regime for cases of severe infection.

Adult↗
PubMed1983

Inhibition of phytohaemagglutinin-induced proliferation of human peripheral blood lymphocytes by histamine and histamine H1 and H2 agonists.

Histamine (10(-3)-10(-8) M) inhibits PHA-induced proliferation of human peripheral blood lymphocytes (HPBL). Inhibition is detected at low concentrations of PHA but is rarely observed at high PHA concentrations. The histamine type II (H2) receptor agonists dimaprit, impromidine and 4-methylhistamine (4MH) inhibit HPBL proliferation and the H2 antagonist, cimetidine, reverses histamine-induced suppression of HPBL proliferation. Lymphocyte proliferation is also inhibited by the H1 receptor agonists, 2-pyridylethylamine and 2-thiazoylylethylamine, but only at high concentrations (10(-3) and 10(-4) M). The H1 agonist 2-methylhistamine, suppresses PHA-induced proliferation of HPBL in analogous fashion to histamine. This effect is reversed by cimetidine but not by diphenhydramine suggesting that an H2 receptor interaction is involved.

Cell Division↗
PubMed1982

Effect of breathing pattern on oxygen concentration received from standard face masks.

Standard face masks are widely used for patients who require high oxygen concentrations. A mechanical model was designed to reproduce various respiratory manoeuvres while oxygen was delivered through a standard variable-performance face mask. Over a range of tidal volumes from 300 to 1200 ml and of frequencies from 10 to 30 breaths/min, the received oxygen concentration was lower than the delivered concentration. The disparity between delivered and received oxygen increased with increasing rate and depth of simulated breathing but could be reduced by increasing the flow rate up to 60 l/min. When a turbulent environment was created, the difference between delivered and received oxygen concentrations was exaggerated. Disparities between delivered and received concentrations can be lessened by increasing the flow rate.

Humans↗
PubMed1982

The double contrast barium enema: why bother?

Despite a wealth of publications extolling the virtues of the double contrast barium enema (DCBE), it is clear that change is only gradual and that in many institutions the single contrast, full column barium enema (BE) is still the routine method of colonic investigation. Much of this may be due to a persistent belief, among the unconverted, that what was good enough yesterday is good enough today. There may also be a belief that an old dog cannot learn new tricks. At least, in many cases, he appears unwilling to try. These beliefs are all too often encouraged by a trickle of articles in the world literature that set out to refute the value of DCBE and thereby add fuel to the dying embers of "conservational" radiology. This article is an attempt to explode some of the persistent fantasies regarding DCBE by reviewing the literature, examining misconceptions, and, hopefully, laying them to rest in their graves--the position that overwhelming worldwide evidence as well as our own experience has assigned for them. I believe that there is little evidence to justify continued use of the barium enema as the standard technic for examining the colon.

Barium Sulfate↗
PubMed1982

Most of the murine leukemia virus sequences in the DNA of NIH/swiss mice consist of two closely related proviruses, each repeated several times.

The structure of the endogenous murine leukemia virus (MuLV) sequences of NIH/Swiss mice was analyzed by restriction endonuclease digestion, gel electrophoresis, and hybridization to an MuLV nucleic acid probe. Digestion of mouse DNA with certain restriction endonucleases revealed two classes of fragments. A large number of fragments (about 30) were present at a relatively low concentration, indicating that each derived from a sequence present once in the mouse genome. A smaller number of fragments (one to five) were present at a much higher concentration and must have resulted from sequences present multiple times in the mouse genome. These results indicated that the endogenous MuLV sequences represent a family of dispersed repetitive sequences. Hybridization of these same digested mouse DNAs to nucleic acid probes representing different portions of the MuLV genome allowed construction of a map of the sites where restriction endonucleases cleave the endogenous MuLV sequences. Several independent recombinant DNA clones of endogenous MuLV sequences have been isolated from C3H mice (Roblin et al., J. Virol. 43:113-126, 1982). Analysis of these sequences shows that they have the structure of MuLV proviruses. The sites at which restriction endonucleases cleave within these proviruses appeared to be similar or identical to the sites at which these nucleases cleaved within the MuLV sequences of NIH/Swiss mice. This identity was confirmed by parallel electrophoresis. We conclude that the apparently complex pattern of endogenous MuLV sequences of NIH/Swiss mice consists largely of only two kinds of provirus, each repeated multiple times at dispersed sites in the mouse genome.

Animals↗
PubMed1982

Management of chronic peritoneal catheter malfunction.

This paper presents a modification of Tenckhoff's insertion procedure for chronic peritoneal dialysis catheters and reviews the results of a technique of management of catheter malfunction by manipulation which obviates the need for catheter replacement. 43 catheters in 33 patients were observed for no less than 1 year. Catheters which malfunctioned within 3 weeks benefited only marginally from manipulation. In those catheters which functioned for more than 3 weeks, manipulation extended mean survival time by 103% (8.5-17.3 months) and overall survival did not differ statistically from catheters not requiring manipulation. The technique is safe and simple and contributes to the effective management of patients undergoing chronic peritoneal dialysis.

Adult↗
PubMed1982

Comparison of timolol/hydrochlorothiazide/amiloride ('Moducren') with cyclopenthiazide/potassium in mild to moderate hypertension.

An open study was carried out in 641 patients with mild to moderate hypertension seen in general practice to assess the effectiveness of treatment with a timolol/hydrochlorothiazide/amiloride preparation compared with cyclopenthiazide/potassium. The timolol/hydrochlorothiazide/amiloride preparation produced better control of blood pressure in a larger percentage of patients after 2 and 6 weeks of treatment than did the diuretic/potassium preparation, and more patients were maintained on 1 tablet per day. Both treatments reduced the number of symptoms complained of by the patients at the initial visit.

Adult↗
PubMed1982

Screening for depression and anxiety in the post-natal period: acceptance or rejection of a subsequent treatment offer.

A technique is described for the potential secondary prevention of post-natal depression and anxiety. All mothers attending Baby Health Centres in one Shire were screened with self-rating scales for depression and anxiety at six to eight weeks postpartum. Six per cent of mothers scored as suspected cases of depression and 11.6% as suspected cases of anxiety. The subsequent course of these suspected cases was checked by screening again at six months. Twelve suspected depressed mothers were offered a psychiatric interview and 50% refused this offer. Possible reasons for treatment refusal are discussed. The feasibility of introducing screening for affective disturbance as a routine procedure in Baby Health Centres is commented upon.

Adult↗
PubMed1981

Relative activities of atenolol and metoprolol on the cardiovascular system of man.

The effects or oral atenolol (100 mg once/day) and metoprolol (100 mg once/day, 100 mg twice/day and 300 mg once/day) have been compared with placebo on the heart rate and systolic blood pressure responses to exercise in 5 healthy volunteers. The drugs were given for 5 days in a double blind randomised fashion with each volunteer receiving each dose of drug. Measurements were made after the first dose on day 1 and after 5 days of dosing. The results on both heart rate and systolic blood pressure showed that overall (over a 24 h period) after acute (day 1) or after chronic (5 days) dosing, atenolol 100 mg once/day, metoprolol 100 mg twice/day and 300 mg once/day, were equivalent as beta-adrenoceptor blocking doses. Thus milligram for milligram atenolol and metoprolol do not produce equivalent blockade on the cardiovascular system of man.

Adolescent↗
PubMed1981

Bond strength of three orthodontic adhesives.

A method was devised to study the bond strength of direct-bonding orthodontic adhesives. A shear load was applied parallel to the tooth-adhesive-bracket interface by means of an Instron Universal Testing Machine. The bond strength was found to increase for some products after 27 days. However, no significant differences could be detected 1 day after placement. The interface was studied to determine the mode of failure. In all cases bond failure occurred as mixed adhesive-cohesive phenomena.

Acrylic Resins↗
PubMed1981

Role of hydrogen peroxide in neutrophil-mediated destruction of cultured endothelial cells.

Human neutrophils stimulated with phorbol myristate acetate were able to destroy suspensions or monolayers of cultured human endothelial cells. Neutrophil-mediated cytotoxicity was related to phorbol myristate acetate concentration, time of incubation and neutrophil number. Cytolysis was prevented by the addition of catalase, while superoxide dismutase had no effect on cytotoxicity. The addition of the heme-enzyme inhibitors, azide or cyanide, markedly stimulated neutrophil-mediated damage while exogenous myeloperoxidase failed to stimulate cytolysis. Neutrophils isolated from patients with chronic granulomatous disease did not destroy the endothelial cell targets while myeloperoxidase-deficient neutrophils successfully mediated cytotoxicity. Endothelial cell damage mediated by the myeloperoxidase deficient cells was also inhibited by catalase but not superoxide dismutase. The addition of purified myeloperoxidase to the deficient cells did not stimulate cytotoxicity. Glucose-glucose oxidase, an enzyme system capable of generating hydrogen peroxide, could replace the neutrophil as the cytotoxic mediator. The addition of myeloperoxidase at low concentrations of glucose oxidase did not increase cytolysis, but at the higher concentrations of glucose oxidase it stimulated cytotoxicity. The destruction of endothelial cells by the glucose oxidase-myeloperoxidase system was inhibited by the addition of hypochlorous acid scavengers. In contrast, neutrophil-mediated cytolysis was not effectively inhibited by the hypochlorous acid scavengers. Based on these observations, we propose that human neutrophils can destroy cultured human endothelial cells by generating cytotoxic quantities of hydrogen peroxide.

Cell Survival↗
PubMed1981

Mammographic practice and dosimetry in Britain.

A survey of mammographic techniques and dosimetry in 61 NHS centres in Britain has been completed. Physical parameters measured at each centre included tube output, half-value thickness, peak kilovoltage, surface dose and percentage depth dose. Ionisation and thermoluminescence dosimetry were employed and image quality was assessed subjectively using a test phantom. Absorbed doses are given at the plane surface of an average-sized, 5 cm thick homogenous breast composed of 50% fat and 50% water. The doses fall naturally into the four combinations of molybdenum (Mo) and tungsten (W) targets and film (F) and xerox (X) receptors. The Mo/X group produced the best images of the phantom but also the highest mean dose of 3.26 cGy (rad) for a cranio-caudad (c-c) view and its use does not seem justified for asymptomatic screening. The Mo/Lo-Dose or MIN-R film combination gave a mean dose of 0.95 cGy(rad) for a c-c view whereas the W/X group gave 0.89 cGy(rad) and superior image quality. The W/F group gave the poorest image quality and its continued use for mammography is questionable.

Female↗
PubMed1980

Genetic structure and genetic variation of influenza viruses.

The following contribution summarizes our most recent results concerning analysis of the influenza A, B and C virus genomes. In addition, we present data on the extent of genetic variation of H1N1 influenza viruses isolated during the months following the 1977 outbreak of H1N1 influenza in China and Russia. A detailed description of these results is published elsewhere.

Base Sequence↗
PubMed1980

Laparoscopic tubal electrocoagulation for sterilization: 5000 cases.

Five thousand cases of laparoscopic tubal electrocoagulation were performed for voluntary interval sterilization in outpatient Thai women from January 1974 through June 1978. Immediate complications occurring during surgery resulted from mesosalpingeal hemorrhage, which was successfully managed by omental packing with or without repeated electrocoagulation. The overall failure rate was 0.40%. The authors find this method of tubal electrocoagulation for fertility management to be reliable and safe as an outpatient procedure and to provide rapid convalescence.

Electrocoagulation↗