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Biomedical subjects

P Elliott

Publications and source records attributed to P Elliott.

At least 199 records · Page 11Linked to original sources
PubMed1989

The INTERSALT study: relations of body mass index to blood pressure. INTERSALT Co-operative Research Group.

In INTERSALT, the relationship between body mass index (kg/m2) and blood pressure was studied in 10,079 men and women aged 20-59, sampled from 52 centres around the world, based on a standardised protocol with central training of observers, a central laboratory and extensive quality control. Body mass index-blood pressure relationships were first studied in men and women within each centre, and results of these regression analyses were then pooled for all 52 centres. With adjustment for age, alcohol intake, smoking, and sodium and potassium excretion, body mass index was positively associated with systolic blood pressure among men in 51 of 52 centres and among women in 47, significantly so in 24 and 27, respectively. Body mass index was positively associated with diastolic blood pressure in 51 and 49 centres in men and women, respectively, significantly so in 33 and 31. When the within centre regression coefficients were pooled, the pooled coefficients were highly significant in all analyses (P less than 0.001), and were similar for those aged 20-39 and 40-59. Overall, a 10 kg difference in body weight was associated on average with a 3.0 mmHg difference in systolic and a 2.2 mmHg difference in diastolic pressure. In further analyses across centres, median body mass index was related significantly to median systolic blood pressure, median diastolic pressure and the prevalence of hypertension in both men and women. Body mass index was related to the slopes of systolic and diastolic blood pressure with age in women, but not in men. These INTERSALT findings confirm the importance of the association between body weight and blood pressure. Differences of 2-3 mmHg in systolic blood pressure on a population basis have been shown to be associated with differences in stroke mortality rates of 6-9 per cent and in coronary death rates of 4-6 per cent.

Adult↗
PubMed1989

The INTERSALT study: results for 24 hour sodium and potassium, by age and sex. INTERSALT Co-operative Research Group.

The relations by age and sex of urinary sodium, potassium and sodium/potassium ratio to blood pressure were examined in the 5,045 men and 5,034 women of the INTERSALT Study. With adjustment for age, and combining (pooling) regression coefficients over the 52 centres of the study, sodium excretion was positively and significantly related to the blood pressure of individuals in both men and women. These positive and significant relationships were also found in seven of eight age-sex specific analyses. In most analyses, z-scores suggested stronger associations in women than in men: the size of regression coefficients in women was as much as twice that of the corresponding coefficients in men. In age-specific analyses for men and women combined, sodium excretion was positively related to blood pressure, significantly so for systolic pressure at all ages and for diastolic pressure at ages 50-59; regression coefficients tended to be larger at older compared to younger ages. Results for sodium/potassium ratio in individuals were similar to those for sodium, being stronger in women than in men, and (at least for systolic pressure) at older compared to younger ages. With adjustment for confounding variables, potassium excretion was negatively and significantly related to the blood pressure of individuals; again these relationships tended to be more marked at older ages. Across the centres, median sodium excretion was positively and significantly related to the slope of systolic and diastolic blood pressure with age in men, in both the 52 and 48 centre analyses, and with and without adjustment for confounding variables.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

The depolarizing action of 5-hydroxytryptamine on rabbit isolated preganglionic cervical sympathetic nerves.

This study describes a depolarizing action of 5-hydroxytryptamine (5-HT) on rabbit isolated preganglionic cervical sympathetic nerves using an extracellular recording technique. From cumulative concentration-response curves for 5-HT (1 mumol/l-1 mmol/l), the mean maximal depolarization was shown to be 277 +/- 32 microV and EC50 was 9.4 mumol/l (6.5-13.6 mumol/l, geometric mean, 95% confidence limits, n = 42). The responses to 5-HT displayed marked tachyphylaxis. When cumulative concentration-response curves to 5-HT and 2-methyl-5-HT were determined in the same preparations (n = 4), the mean maximal response to 5-HT was 519 +/- 167 microV, EC50 32.2 mumol/l (8.8-118 mumol/l) and the mean maximal response to 2-methyl-5-HT was 317 +/- 63 microV, EC50 35.1 mumol/l (12.9-95.5 mumol/l, geometric means, 95% confidence limits). The action of selective 5-HT antagonists was tested on repeated cumulative concentration-response curves to 5-HT. Neither methiothepin (0.1-1 mumol/l, n = 3) nor ketanserin (0.1-1 mumol/l, n = 3) had an action on 5-HT responses. The selective 5-HT3 antagonists MDL 72222, ICS 205-930 and SDZ 206-830 were all potent antagonists of the 5-HT depolarizations. The action of these antagonists was quantified by determining the apparent pA2 from the dose ratios and a Schild plot.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Synthesis and immunological evaluation of N-terminal, noncrossreactive tachykinin antigens.

The N-terminal hexa- or pentapeptide sequences of the three mammalian tachykinins substance P, neurokinin A, and neurokinin B have been synthesized by the conventional solid-phase procedure with 6-aminocaproyl-S-(acetamidomethyl)cysteine as a C-terminal spacer and attachment function. A fourth sequence, with an additional N-terminal 6-aminocaproyl residue on the substance P-hapten sequence, was cyclized N- to C-terminally. For this purpose, a four-level protection scheme has been applied: BOC-TFA for N-terminal protection and cleavage; TFA-stable but HF-labile anchoring function and side-chain protection; S-acetamidomethyl for semipermanent thiol protection. The side chain amino function of Lys was protected with NO2Z, stable against HF but readily cleaved with hydrogenation. The hapten sequences were coupled to maleimidated BSA, after the Acm group was removed by mercury/hydrogen sulfide treatment. Mice immunized with the three linear hapten sequences produced sera that were specific in enzyme-linked immunosorbant assay for the presented hapten and the respective tachykinin but displayed no crossreactivity at all toward the other haptens nor to one of the other tachykinins. It is concluded that this approach produced antisera, specific and selective for its respective mammalian tachykinins.

Animals↗
PubMed1988

Intraocular pressure changes during rapid sequence induction of anaesthesia: comparison of propofol and thiopentone in combination with vecuronium.

Intraocular pressure (IOP) was measured during rapid sequence induction of anaesthesia using thiopentone or propofol as the induction agent and vecuronium for neuromuscular blockade. Vecuronium was administered in a dose of 0.15 mg kg-1 approximately 35 s before the induction agent. IOP was measured with a handheld applanation tonometer before anaesthesia, following administration of the induction agent, immediately after tracheal intubation and cuff inflation and 1, 2 and 3 min later. IOP in the propofol group was significantly lower than in the thiopentone group, except immediately after induction, when reduction in IOP was similar and significant with both agents. IOP following intubation in patients in whom anaesthesia was induced with thiopentone was not significantly different from baseline values, but showed a significant increase from the pressure before intubation. In contrast, IOP after intubation in the propofol group remained not only significantly less than the baseline value, but also showed only a minimal and insignificant change in comparison with values before intubation. The frequency of side effects was low in both groups except for a significantly greater reduction in arterial pressure in those receiving propofol.

Adult↗
PubMed1988

Intra-ocular pressure changes during induction of anaesthesia and tracheal intubation. A comparison of thiopentone and propofol followed by vecuronium.

Intra-ocular pressure was measured during induction of anaesthesia with propofol (n = 40) or thiopentone (n = 40) followed by vecuronium to facilitate tracheal intubation which was carried out 3 minutes after the administration of relaxant. The average induction doses were 2.15 and 4.83 mg/kg for propofol and thiopentone, respectively. Half the patients in each group received a supplementary dose of the same induction agent (propofol 1.0 mg/kg or thiopentone 2.0 mg/kg) (corrected) prior to intubation. Both propofol and thiopentone produced a significant reduction in intra-ocular pressure which decreased further after administration of vecuronium as well as the second smaller dose of the induction agents. Intra-ocular pressure prior to intubation was lower in the two propofol groups in comparison to the corresponding thiopentone groups. Intubation was associated with an increase in intra-ocular pressure but it still remained significantly below the baseline values except in the group given one dose of thiopentone. Supplementary doses of induction agents before intubation attenuated the increase in intra-ocular pressure. Propofol was significantly more effective in this respect and this group showed the lowest intra-ocular pressure throughout the study period. However, administration of propofol resulted in a 30% incidence of pain on injection and a decrease in systolic arterial pressure of more than 30% in about half the patients.

Adolescent↗
PubMed1988

Reproductive performance in C57BL and I strain mice.

Mice of the I strain are regarded as difficult to breed. To characterize and elucidate the cause of poor reproductive performance in I strain mice, records of reproductive performance were analyzed from Cancer Research Laboratory, Kirschbaum Memorial Laboratory and Strong Research Laboratories which had bred the I strain mice and a control strain, C57BL, and compared with data from Jackson Laboratory and from three dietary studies conducted in this laboratory. Reproductive performance in the I strain mice is characterized by fewer productive matings, fewer litters and smaller litters than C57BL mice. Also, fewer mice of the I strain survive to weaning. These factors result in the production of only half as many mice per dam in the I strain as the C57BL mice. The fewer number of litters is not due to a greater proportion of resorptions in the I mice, nor are there differences in the survival of either sex. Diets which contain slightly higher (8-12 mg per kg of diet) amounts of pyridoxine (PN) than recommended (1-6 mg per kg of diet) improve performance in the I strain. However, 410 or 1230 mg PN does not increase productivity further. That survival rate of the C57BL mice improves with higher amounts of PN (410 and 1230 mg diets), suggests another dietary factor may be limiting for I strain mice. The reproductive performance in I strain mice is better with diets which result in a higher body weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Sodium and blood pressure: positive associations in a north London population with consideration of the methodological problems of within-population surveys.

Blood pressure (BP) and 24-hr urinary sodium (Na) and potassium (K) excretion were measured in 58 men and women aged 40 and above who were selected randomly from the age-sex register of a general practice in North London. All 58 urine collections were reported as complete, but only 28/56 (50%) were classified as 'complete' by the excretion of a biological marker, p-aminobenzoic acid (PABA). Reliability of Na excretion estimated from repeated urine collections was 0.86, indicating that variability of Na excretion within individuals in this middle-aged and elderly population was low. Systolic blood pressure (SBP) was significantly related to 24-hr Na excretion and to 24-hr Na/creatinine ratio. After adjustment for age, sex and body mass index, a SBP-Na regression coefficient of 0.091 mmHg/mmol Na (P = 0.02) was observed. On simple regression analysis, a significant association was also found between diastolic blood pressure and Na (P = 0.04). In the sub-group classified as 'complete' collectors by PABA excretion, BP-Na regression coefficients were larger than in analyses of the sample as a whole. BP was not significantly related to K or Na/K.

4-Aminobenzoic Acid↗
PubMed1987

Hepatitis B vaccine: immunogenicity and follow-up including two year booster doses in high-risk health care personnel in a London teaching hospital.

One hundred forty-four adult health care personnel (aged 18-62 years, median 33 years) considered at high risk of future HBV infection were vaccinated with a plasma-derived hepatitis B vaccine (20 micrograms HBVax at 0, 1, and 6 months) and followed-up for 2 years. Anti-HBs was present in only 6.9% prior to vaccination, and prescreening to detect this group would not have been cost-effective. At 9 months, 8.3% were nonresponders and a further 9% had anti-HBs levels less than 50 mIU/ml. Multivariate analysis showed that age was the single most important determinant of a poor response. In 47 of 52 individuals retested 2 years later, anti-HBs levels had fallen by 80% or more, and in four it had become undetectable. Response to a booster dose at this stage was excellent, with anti-HBs levels 3 months later much higher than at the end of the initial course. Additional booster doses of vaccine in two of the initial nonresponders at 14 and 22 months, respectively, also led to seroconversion. Although a significant proportion of health care workers in this study did not make a satisfactory response to the hepatitis B vaccine, later booster doses were very effective in subsequently increasing anti-HBs levels.

Adolescent↗
PubMed1987

The effects of vecuronium on intra-ocular pressure.

The effects of vecuronium on intra-ocular pressure were investigated in doses of 0.1 mg/kg during steady state anaesthesia (n = 5), 0.1 mg/kg as part of a normal sequence induction preceded by thiopentone (n = 10), and 0.15 mg/kg as part of a rapid sequence induction with vecuronium administered prior to thiopentone (n = 10). Administration of vecuronium during steady state anaesthesia was associated with a significant decrease. Vecuronium produced a small reduction in pressure during a normal sequence induction, following a significant reduction after thiopentone. Tracheal intubation during normal sequence and rapid sequence inductions produced increases in pressure above the pre-intubation value (significantly so in the case of normal sequence induction); however, the intra-ocular pressure always remained below the pre-induction value, which suggests that vecuronium 0.15 mg/kg is a suitable relaxant as part of a rapid sequence induction technique where the use of suxamethonium is contraindicated.

Adult↗
PubMed1987

Diet, alcohol, body mass, and social factors in relation to blood pressure: the Caerphilly Heart Study.

Data for 387 men who had completed seven-day weighed dietary records as part of the Caerphilly Heart Study were examined for relations of alcohol, diet, body mass index (BMI), and other variables to blood pressure. These included age, smoking, exercise, and social class. For men not on antihypertensive treatment (n = 356) regression analysis showed that age (p less than 0.001), BMI (p less than 0.05), and alcohol intake (p less than 0.01) were significantly related to systolic blood pressure, and BMI (p less than 0.001) and alcohol intake (p less than 0.01) to diastolic blood pressure. In addition, protein intake (p less than 0.05) was significantly and inversely related to the risk of being hypertensive, but other dietary variables were not related to blood pressure. For men on antihypertensive treatment (n = 31) significant inverse correlations were observed between diastolic blood pressure and the intakes of potassium (p less than 0.01), fibre (p less than 0.001), polyunsaturated fat (p less than 0.01), and a number of other dietary variables. Reasons for these differences are discussed.

Age Factors↗
PubMed1986

Effect of pretreatment with ranitidine on the hypnotic action of single doses of midazolam, temazepam and zopiclone. A clinical study.

Patients receiving midazolam, temazepam or zopiclone by mouth as premedication for minor gynaecological surgery were pretreated with either ranitidine or an inert tablet. Pretreatment with ranitidine was associated with a greater degree of drowsiness at 20 and 40 min after midazolam, and a shorter mean time to peak hypnotic effect than in the non-pretreated group. Ranitidine did not affect the degree of drowsiness in the patients receiving temazepam or zopiclone.

Adolescent↗