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Biomedical subjects

J Edwards

Publications and source records attributed to J Edwards.

At least 217 records · Page 12Linked to original sources
PubMed1991

Demonstration that bone mass is greater in black than in white children.

Osteoporosis and hip fractures are less common and bone mass is greater in black than in white women. To determine if bone mass is greater in black than in white children, bone mineral density (BMD) of the midradius by single-photon absorptiometry and BMD of the lumbar spine (L1-L4), trochanter, and femoral neck by dual-photon absorptiometry were measured in 20 black boys, 18 black girls, 33 white boys, and 35 white girls between the ages of 7 and 12 years. Mean age (10.4 +/- 0.3 versus 10.2 +/- 0.2 years) and body weight (39 +/- 2 versus 38 +/- 2 kg) in the blacks and whites, respectively, were not different in the two groups, and the ages and weights of the boys and girls were not different from each other. BMD were significantly greater in black than in white children at each site, in the black than in white boys at the trochanter and femoral neck, and in the black than in white girls at each site. In both races, BMD varied directly with age and body weight. Multivariate analysis showed that BMD were greater at the midradius, lumbar spine, trochanter, and femoral neck in the black than in the white children, that BMD of the lumbar spine was greater in the girls than in the boys, and that BMD of the trochanter and femoral neck were greater in the boys than in the girls. There were significant partial correlations between race and BMD and between BMD and body weight at each site, between sex and BMD at the lumbar spine, trochanter, and femoral neck, and between age and BMD at the midradius, trochanter, and femoral neck. Race, sex, age, and body weight together accounted for 49-66% of the variation in bone mass. Thus, BMD of the midradius, spine, and hip are greater in black than in white children, body weight and age are important determinants of bone mass, and some sex differences in bone mass are present at this age.

Absorptiometry, Photon↗
PubMed1991

Hormonal receptors in locally advanced breast cancer: change with response to neoadjuvant chemotherapy?

Twenty-one cancers in 20 patients with locally advanced breast cancer were studied. Incisional biopsy was performed without using electrocautery. Tissue was obtained for histology and estrogen (ER) and progesterone (PR) receptors. Patients received chemotherapy after biopsy. All responded and had radical mastectomy performed. Tissue was removed from the mastectomy specimen to confirm residual tumor and for repeat receptor measurements. Initial receptor levels were negative in 13 cancers. Following chemotherapy, both ER and PR levels were unchanged in 11 cancers. Levels in one cancer changed from ER-PR- to ER+PR- and one changed from ER-PR- to ER+PR+. Six cancers were ER+PR+ at initial examination. Repeat receptor levels after chemotherapy were ER+PR+ in three. One ER+PR+ tumor became ER-PR+, one changed to ER+PR-, and one to ER-PR-. One ER+PR- cancer remained ER+PR- after treatment and an ER-PR+ cancer became ER-PR- after treatment. Chemotherapy dose not significantly alter hormonal levels in breast cancer tissue.

Aged↗
PubMed1991

Sindbis virus infection of a Chinese hamster ovary cell mutant defective in the acidification of endosomes.

Sindbis virus infection of a Chinese hamster ovary temperature-sensitive mutant cell line defective in its ability to acidify endosomes was examined to evaluate the importance of this step in the process of alphavirus penetration of host cells by measuring the time at which viral RNA synthesis was initiated. We found that RNA synthesis was initiated in these mutant cells at the same time after addition of virus at either permissive or nonpermissive temperature. We conclude that exposure to the acidic environment of an endosome is not a prerequisite for alphavirus infection.

Animals↗
PubMed1991

HIV prevalence and risk behaviours for HIV transmission in South Australian prisons.

During the latter half of 1989, HIV prevalence in South Australian prisoners was 1.4%. The prevalence of HIV infection across the prison system did not change significantly during 1989 but there was clustering of HIV-infected prisoners in some prisons. Almost half the prisoners from all of the South Australian prisons agreed to participate in our studies, from which we estimate that about 42% of prisoners engage in risk behaviours at least once while incarcerated. Prisoners estimated that 36% of all prisoners inject drugs intravenously at some stage during their stay and that 12% engage in anal intercourse at least once. Interviews with former prisoners who had a history of intravenous drug use revealed that about half had injected themselves while in prison, 60% shared needles and most did not clean shared needles adequately. Most of these prisoners injected themselves once a month or less frequently. The conditions for spread of HIV within the prison system exist but at the current prevalence of infection, transmission can be expected to be infrequent. The opportunity exists now to improve and expand preventive measures.

Adult↗
PubMed1991

Modification of pain on injection of propofol--a comparison between lignocaine and procaine.

Pain on injection of propofol was assessed in a controlled, randomised study of 273 patients. They received either lignocaine 10 mg, procaine 10 mg or isotonic saline 0.5 ml, 15 seconds before the injection of propofol into a vein on the back of the hand. The incidence of pain on injection in the control group (51%) was comparable with other studies. Lignocaine and procaine both significantly reduced the pain (35% and 34% respectively, p less than 0.05) but there was no statistical difference between these two groups.

Adolescent↗
PubMed1991

Diagnosing personality disorders in psychiatric inpatients.

This study investigated assumptions made by DSM-III and DSM-III-R regarding Axis I-Axis II associations and sex differences for the 11 personality disorders (PD). A total of 112 patients formed 4 Axis I diagnostic groups: recent-onset schizophrenia (n = 35); recent-onset mania (n = 26); unipolar affective disorder (n = 30); and a mixed diagnostic group (n = 21). The prevalence of PD was determined using the Structured Interview for DSM-III Personality Disorders (SIDP). Schizophrenia was associated with antisocial PD and schizotypal PD; manic disorder was associated with histrionic PD; and unipolar affective disorder was associated with borderline, dependent and avoidant PD. Some of these results were consistent with DSM-III/DSM-III-R postulates. However, there was little support for the DSM-III/DSM-III-R statements on sex differences in the prevalence of PD, except for antisocial PD. The implications of the results for DSM-III/DSM-III-R assumptions are discussed.

Adult↗
PubMed1991

The articulatory kinematics of final lengthening.

In order to understand better the phonetic control of final lengthening, the articulation of phrase-final syllables was compared with that of two other contexts known to increase syllable duration: accent and slow tempo. The kinematics of jaw movements in [pap] sequences and of lower lip movements in [pe] sequences for four subjects were interpreted in terms of a task-dynamic model. There was evidence of two different control strategies: decreasing intragestural stiffness to slow down some part of the syllable, and changing intergestural phasing to decrease overlap of the vowel gesture by the consonant. The first was used in slowing down tempo, whereas the second was used to increase the duration of accented syllables over unaccented syllables. Both strategies were implicated in phrase-final lengthening. In accented syllables, final closing gestures generally were longer and slower, but not more displaced. The two slowest subjects, however, used the other strategy in their slow-tempo final syllables. Final lengthening in reduced syllables was more difficult to interpret. The relationship between peak velocity and displacement suggested that a lesser stiffness is obscured by an increased gestural amplitude. Thus, by comparison to lengthening for accent, final lengthening is like a localized change in speaking tempo, although it cannot be equated directly with the specification of stiffness.

Adult↗
PubMed1990

Age-related prognosis after acute myocardial infarction (the Multicenter Diltiazem Postinfarction Trial).

The basis for the excess mortality with age after acute myocardial infarction (AMI) is not clear, nor is it known whether the mode of death is altered with age. Age-related factors predictive of mortality and age-related mechanisms of the 333 deaths were examined in 2,466 patients who were enrolled in a placebo-controlled trial to determine the effect of diltiazem on mortality and reinfarction after AMI. There were 3 age groups with increasing mortality rates: ages 25 to 49 (n = 499), 50 to 64 (n = 1,228) and 65 to 75 years (n = 739). There was a significant age-related increase in the proportion of patients with baseline risk factors. These baseline characteristics did not differ by treatment (placebo vs diltiazem). However, multivariate survivorship analysis still identified age as an independent risk factor for cardiac death. The proportion of arrhythmic and myocardial failure deaths did not differ by treatment or age group.

Adult↗
PubMed1990

The effects of inhibitors of arachidonate metabolism on spontaneous and evoked endplate potentials at normal and crotoxin-treated frog neuromuscular junctions.

Aspirin (1 mM), a selective cyclooxygenase inhibitor, decreased endplate potential (e.p.p.) amplitude but did not affect either the biphasic changes in m.e.p.p. frequency or triphasic changes in e.p.p. amplitude induced by crotoxin. Nordihydroguaiaretic acid (30 microM), a dual inhibitor of cyclooxygenase and lipoxygenase pathways, increased e.p.p. amplitude but did not affect the characteristic changes in m.e.p.p. frequency and e.p.p. amplitude in response to crotoxin. The incidence of giant m.e.p.p.s was reduced by aspirin and increased by NDGA. Arachidonate metabolism is not a major factor in the induction of neurotoxicity by crotoxin at the frog neuromuscular junction.

Animals↗
PubMed1990

Antidepressant or antianxiety? A study of the efficacy of antidepressant medication.

The authors analyzed the relative contributions of improvement in depressive and anxiety symptoms, as measured by the Hamilton Rating Scale for Depression (HRSD) and the Hamilton Rating Scale for Anxiety (HRSA), respectively, after 1 week of treatment to the prediction of improvement in HRSD score after 6 weeks of antidepressant pharmacotherapy. Fifty-six subjects completed 6 weeks of treatment with either desipramine (n = 20), alprazolam (n = 18), or a desipramine-alprazolam combination (n = 18). The results showed that early improvement in the HRSD was a moderately strong predictor of the total 6-week improvement in HRSD score, and a better predictor than early improvement in the HRSA. Partial correlations showed that early HRSD improvement was significantly related to total HRSD improvement within the alprazolam group. This pattern of response differed from those observed for the other treatment groups. Desipramine-treated subjects showed gradual improvement over the course of the study, and the improvement in week 1 was not so strongly predictive of overall improvement. The relationship between early and total HRSD improvement for the combination treatment group was intermediate to the other two groups. These findings are discussed in the context of the relationship between depression and anxiety, and potential implications for the treatment of these overlapping and often mixed syndromes.

Adult↗
PubMed1990

Cloning and heterologous expression of the penicillin biosynthetic gene cluster from penicillum chrysogenum.

A cosmid clone containing the putative penicillin biosynthetic gene cluster from Penicillium chrysogenum was used to transform the related filamentous fungi Neurospora crassa and Aspergillus niger, which do not produce beta-lactam antibiotics. Both of the transformed hosts contained intact P. chrysogenum DNA derived from the cosmid clone and produced authentic penicillin V. Assays of penicillin biosynthetic enzyme activity additionally demonstrated that they possessed delta-(L-alpha-amino-adipyl)-L-cysteinyl-D-valine synthetase (ACVS), isopenicillin N synthetase (IPNS) and acyl coenzyme A:6-aminopenicillanic acid acyltransferase (ACT) activity. The data suggests that genes encoding all the enzymes necessary for the biosynthesis of penicillin from amino acid precursors are closely linked in P. chrysogenum and constitute a gene cluster.

Acyltransferases↗
PubMed1990

Rotation and translation of the jaw during speech.

A two-dimensional rigid-body model of jaw movement was used to describe jaw opening and closing gestures for vowels and for bilabial and alveolar consonants. Jaw movements were decomposed into three components: (a) rotation about the terminal hinge axis, (b) the horizontal translation of that axis, and (c) the vertical translation of that axis. Data were collected for 3 subjects in two separate recording sessions. Multiple regression analysis was used to examine the relationships among the three jaw movement components. For 2 subjects, but not for the third, an interdependence between jaw rotation and the first principal component of jaw translation, horizontal translation, was observed. For these 2 subjects, the first degree of freedom of jaw movement corresponded to a combination of rotation and the first principal component of jaw translation. For the third subject, the first degree of freedom of jaw movement corresponded to rotation alone. The results of this study, like those of Westbury (1988), indicate that an accurate description of jaw movement during speech requires the recording of two points of jaw movement.

Adult↗