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Biomedical subjects

A Round

Publications and source records attributed to A Round.

At least 37 records · Page 2Linked to original sources
PubMed1997

Atomic force microscopy of plant cell walls, plant cell wall polysaccharides and gels.

Methods developed for the routine imaging of polysaccharides by atomic force microscopy (AFM) have been used to image plant polysaccharides from higher plants (pectin) and algae (carrageenan). These methods have been extended to image K-carrageenan association in hydrated films. Finally, AFM has been used to image polysaccharide architecture in moist plant cell walls. Simple experimental and image processing methods have been used to enhance molecular structure in 'rough' cell wall surfaces.

Cell Wall↗
PubMed1997

Emergency medical admissions to hospital--the influence of supply factors.

A retrospective review of all adult medical in-patient hospital records in one health district (adult population 378,000) was performed over three consecutive years. Yearly age-standardised rates for emergency admissions were calculated and compared between sections of the population with differing access to hospital beds. Confounding and other explanatory variables were examined with a logistic regression model. Emergency medical admission rates were consistently higher in the population whose general practitioner had access to community hospital beds, as compared with those whose general practitioner had no access, (46.1 per thousand population vs 39.3 per thousand in the year 1994-95, difference significance, P < 0.05). Multivariable analysis suggests that in addition to supply factors, age, sex, morbidity and socio-economic circumstance influence admission rates.

Adolescent↗
PubMed1995

Divergent views--patient, career and staff perceptions of diagnosis and reasons for psychiatric admission to a district general hospital.

This study explores the differing perceptions of patients, carers, and professional staff in relation to psychiatric admission. There is poor to moderate agreement between lay people and professional beliefs about diagnosis or purpose of admission, although good agreement about the necessity of admission. The chronicity of symptoms in admitted patients and a rural-urban divide in rates of admissions are also noted.

Adolescent↗
PubMed1993

Incidence of severe acute renal failure in adults: results of a community based study.

OBJECTIVE: To determine the age related incidence of severe acute renal failure in adults in two health districts in England. DESIGN: Prospective study of patients identified as having severe acute renal failure within a two year period; subsequent monitoring of outcome for a further two years. SETTING: Two health districts in Devon. SUBJECTS: Those adults in a population of 444,971 who developed severe acute renal failure (serum creatinine concentration > 500 mumol/l) for the first time during two years, with subsequent fall of the serum creatinine concentration below the index value. MAIN OUTCOME MEASURES AND RESULTS: 125 adults (140 per million total population yearly, 172 per million adults) developed severe acute renal failure, of whom 90 (72%) were over 70. Age related incidence rose from 17 per million yearly in adults under 50 to 949 per million yearly in the 80-89 age groups. In 31 patients (25%) the cause was prostatic disease, which was related to a good prognosis (84% (26) alive at three months). Overall survival was 54% (67) at three months and 34% (42) at two years and was not significantly age related. 18 per million total population yearly (22 per million adult population) received acute dialysis. Referral rate for specialised opinion was 51 per million total population yearly with an estimated appropriate referral rate of 70 per million per year. CONCLUSIONS: The incidence of severe acute renal failure in the community is at least twice as high as the incidence reported from renal unit based studies. Prostatic disease, a preventable and treatable problem, is the most common cause. Survival figures indicate that age alone should not be a bar to specialist referral or treatment.

Acute Kidney Injury↗
PubMed1990

Clinical diagnosis of tamponade in Malawi.

A consecutive series of 25 Malawian patients with tamponade secondary to tuberculosis were compared to 25 patients with congestive cardiac failure, without pericardial effusion in a retrospective study. More patients with tamponade had an impalpable apex beat (21/1), pulsus paradoxus (13/0), soft heart sounds (13/2), paradoxical rise in jugular venous pressure (6/0), and fewer had a murmur (1/14). All these results are significant (p less than 0.05) by the chi 2 test with Yates' correction. The presence of two or more of these discriminating physical signs has a positive predictive value of 75 per cent, and a negative predictive value of 99.5 per cent for the diagnosis of tamponade. Clinical diagnosis of tamponade by primary health care personnel in Malawi should be possible, and lead to earlier treatment.

Adolescent↗
PubMed1987

Further studies on the blockade of 5-HT depolarizations of rabbit vagal afferent and sympathetic ganglion cells by MDL 72222 and other antagonists.

The blocking action of MDL 72222 (1 alpha H, 3 alpha, 5 alpha H-tropan-3-yl-3, 5-dichlorobenzoate at 5-hydroxytryptamine (5-HT) receptors on nodose (NG) and superior cervical ganglia (SCG) has been investigated further. The sucrose-gap technique was used to record potential changes from populations of neurones. The surmountable blockade induced by small concentrations of the antagonist was quantified and the blocking potency compared with that of a number of other compounds. In nodose ganglia three 4-5 point dose-response (DR) curves were established, using bolus injections of 5-HT (5-80 nmol). The mean amplitude of the response to 80 nmol was 4.18 +/- 0.53 mV and the ED50 was 18.2 nmol. Second and 3rd dose-response curves showed small displacements to the right, indicating a slight reduction in sensitivity. In superior cervical ganglia responsiveness was less. Amounts of 5-HT ranging from 20 to 320 nmol evoked dose-related depolarizations. The mean amplitude of the response evoked by 320 nmol 5-HT was 1.7 +/- 0.14 mV. Three 4-5 point dose-response curves could be elicited from a single ganglion. The ED50 was 55.8 nmol. Initial, 2nd and 3rd dose-response curves could be superimposed, there being no significant rightward shift. The results confirm that MDL 72222 is a potent, selective antagonist at 5-HT receptors in nodose and superior cervical ganglia. In the nodose ganglion, after equilibration for 1 hr with 10(-8) or 10(-7) M MDL 72222, dose-response curves for 5-HT showed rightward, parallel shifts. In contrast, 10(-6) M MDL 72222 or prolonged exposure (3-4 hr) to 10(-8), 10(-7) or 10(-6) M caused larger rightward shifts of the dose-response curves and depressed the maximum responses. In the superior cervical ganglion, equilibration for 1 hr with concentrations of 10(-8) or 10(-7) M produced effects on the dose-response curves similar to those seen in the nodose ganglion, but longer exposures (3-4 hr) did not depress the maximum. Apparent pA2 values were determined from individual experiments on both the nodose and superior cervical ganglia, where MDL 72222 (10(-7) M or less, for 1 hr) caused parallel or near parallel shifts of dose-response curves. In the nodose ganglion the apparent pA2 was 7.7 +/- 0.1, while in the superior cervical ganglion it was 7.8 +/- 0.1 (mean +/- SEM). The nature of the blockade induced by prolonged exposures or by concentrations greater than 10(-7) M is discussed.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗
PubMed1986

The depolarizing action of 5-hydroxytryptamine on rabbit vagal afferent and sympathetic neurones in vitro and its selective blockade by ICS 205-930.

Depolarizing responses to 5-hydroxytryptamine (5-HT) were recorded from rabbit nodose (NG) and superior cervical (SCG) ganglia using the sucrose-gap technique. The antagonist potency and selectivity of ICS 205-930 ([3 alpha-tropanyl]-1H-indole-3-carboxylic acid ester) were investigated. In NG, 5-HT (5 to 80 nmol) evoked depolarizations of graded amplitude. The ED50 was 18.2 (10.9-30.5) nmol (geometric mean, 95% confidence limits). Responses were blocked surmountably by ICS 205-930, 10(-11) and 10(-10) M, the threshold for blockade being below 10(-11) M. Parallel, rightward shifts in dose-response curves were seen with these concentrations of antagonist, but at higher concentrations (10(-9) and 10(-8) M) there was a further rightward shift with reduction in slope and maximum of the curves. In SCG, where 5-HT (20 to 320 nmol) evoked depolarizations of graded amplitude and the ED50 was 55.8 (22.3-139.6) nmol (geometric mean, 95% confidence limits), ICS 205-930 had a similar inhibitory effect to that observed in NG. The apparent pA2 values for the surmountable blockade produced by ICS 205-930 at concentrations of 10(-11) and 10(-10) M were 10.2 +/- 0.2 for NG and 10.4 +/- 0.1 for SCG (means +/- s.e. mean). ICS 205-930 was selective in its action since it had no effect on dimethylphenylpiperazinium (DMPP) responses in either ganglion or on GABA responses in NG. This study provides quantitative evidence on the blocking action of ICS 205-930 at neuronal 5-HT receptors using a technique that allows the depolarizing responses evoked by the amine to be directly recorded.

Animals↗