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Biomedical subjects

J Barton

Publications and source records attributed to J Barton.

At least 73 records · Page 4Linked to original sources
PubMed1985

The natural history of subependymal germinal matrix hemorrhage.

A prospective study of 377 premature infants (less than or equal to 1500 gm) was undertaken to delineate the natural history of subependymal/intraventricular hemorrhage (S/IVH) and its complications using ultrasound (US) and computed tomography (CT). Low grade (I, II) S/IVH had a low mortality while higher grades (III, IV) still had elevated mortality rates. The addition of intraparenchymal hemorrhage (IPH) to S/IVH incrementally increased the incidence of death and other complications, suggesting IPH hemorrhage should be categorized separately. When a specific day could be identified, S/IVH had its onset in the first 7 days of life with peak incidence occurring on day 3. S/IVH appeared to be an event limited to less than 24 hours in all but 5% of infants in whom progression of hemorrhage was documented over a 24-hour period. The mortality rate of these progressive hemorrhages was high, 50%. The benign phenomenon of late S/IVH was detected in 5% of infants. These hemorrhages were clinically silent and of minor severity. Several complications of S/IVH were detected. Hydrocephalus was a significant complication only for higher grades of S/IVH. When present, severe hydrocephalus had an early onset and reached a maximum at around 3 weeks of age. "Atrophic change" of a cerebral hemisphere was detected in 30% of all S/IVH infants, while this was not seen in nonS/IVH infants. This "atrophic" abnormality had a marked predilection for the left hemisphere, independent of the site of the S/IVH. Periventricular leukomalacia (PVL) was documented by US in 2% of infants and could be detected in the first week of life. PVL presented in the first week of life as an echogenic lesion which developed "cystic" changes at approximately 3-4 weeks of age. This complication should be categorized separately from S/IVH.

Atrophy↗
PubMed1985

Treatment of urticaria pigmentosa with corticosteroids.

Based on a previous observation that the long-term application of potent topical corticosteroids under occlusion to normal skin resulted in the loss of mast cells, we investigated the effects of intralesional and topical steroids in urticaria pigmentosa (UP). Three patients with UP had lesions that were injected with triamcinolone acetonide. Four weeks after injection, all patients showed a loss of Darier's sign, and, by eight weeks after injection, there was a dramatic clearing of the plaques and a decrease in brown hyperpigmentation. By 12 weeks, mast cells were undetectable by light microscopy and transmission electron microscopy (TEM). The injection sites remained dramatically improved for as long as one year after treatment, and histamine content was reduced 95% in one patient 48 weeks after injection. In six patients, the topical application of 0.05% betamethasone dipropionate under occlusion to limited areas induced almost complete clearing of UP lesions. Lesions treated with an emollient under occlusion, as a control, demonstrated no change. After treatment, no mast cells were seen by light microscopy or TEM, and this persisted for at least 24 weeks. There was also a significant decrease in tissue histamine levels in the treated areas. The treated areas remained clinically improved for at least nine to 12 months. These data indicate that steroid therapy dramatically decreases the excess number of normal-appearing mast cells in UP as well as induces a prolonged resolution of UP lesions. Local corticosteroids thus are a useful therapeutic modality for UP.

Administration, Topical↗
PubMed1984

Inhibition of angiotensin-converting enzyme by dipeptide analogs.

Several dipeptide analogs containing an acyclic teritary amide group are effective angiotensin-converting enzyme (ACE) inhibitors with I50 values comparable to those of the best natural dipeptide inhibitors (e.g. Val-Trp). The most potent inhibitors studied feature a p-tolyl or norbornyl substituent on the amide nitrogen atom and a methyl or butylamino substituent on the carbon atom alpha to the amide group. REV 5277-R, alanyl-N-exo-norbornyl-glycine, is a competitive inhibitor of rabbit lung ACE with a Ki value of 9 microM.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1983

Multi-centre clinical investigation of indapamide in the United States: a review.

Indapamide, a new indoline antihypertensive agent, has been the subject of a worldwide programme to develop this drug for general clinical use. The results are described of the multi-centre U.S. clinical programme demonstrating the effectiveness and tolerance of indapamide for the treatment of hypertension. All work was conducted under U.S. Federal Food and Drug Administration guidelines, and resulted recently in a New Drug Application. A total of 1891 subjects or patients participated in 27 separate studies conducted by 91 investigators. In controlled clinical trials comparing 2.5 mg indapamide once daily with 50 mg hydrochlorothiazide once daily for 40 weeks in patients with mild to moderate essential hypertension, indapamide produced a reduction of supine blood pressure of -9.5/-14.3 mmHg as compared with -7.6/-11.4 mmHg for hydrochlorothiazide. In combination with methyldopa, propranolol, clonidine, guanethidine and hydralazine, indapamide consistently produced a greater decrease in arterial pressure than did those agents given alone. Indapamide added to these step-care agents did not result in a meaningful increase in adverse reactions. Indapamide has been the subject of a long-term safety study in which over 100 hypertensive patients have been followed up for 2 years or longer. During this period of time, indapamide was well tolerated and remained effective. No biochemical, electrocardiographic or ophthalmological changes were associated with its use. Other studies with indapamide are discussed describing the systemic and renal haemodynamic effects, pharmacokinetic properties and special safety studies conducted with this agent. The use of indapamide in patients with hepatic or renal impairment is reviewed in detail.

Antihypertensive Agents↗
PubMed1982

Adaptations of the Denver Developmental Screening Test: a study of preschool screening.

Developmental screening tests are only rarely used in pediatric practice, reportedly because of lack of available time. This study evaluated a shortened form of the Denver Developmental Screening Test (DDST-S) consisting of only those items immediately to the left of the child's individual are line, three in each sector or a total of 12. This DDST-S was administered to four cohorts of preschool children (aged 52 to 64 months), 1,819 children in all. Subsamples of these children returned within three months for one of several developmental (criterion) tests (McCarthy Scales of Children's Abilities, the complete DDST, or the Stanford-Binet). The DDST-S was scored by selecting the profile of passes and failures most predictive of McCarthy test results, using indices of copositivity, connegativity, underreferral, and overreferral as the basis for the decision. Utilizing this scoring system, use of the DDST-S was able to identify low scorers (those scoring less than 70) on the Stanford-Binet (sensitivity = .67, specificity = .95, predictive value = .54, underreferral = 2.5%, overreferral = 4%) as well as the complete DDST. Low scoring children could thus be identified in less than half the time required by the complete DDST. A two-stage DDST-S and DDST procedure was found to have even greater predictive value (76%; 100% if borderline cases [score of 70 to 80] are considered positive) than either form alone.

Child Development↗
PubMed1982

Social image factors as motivators of smoking initiation in early and middle adolescence.

The social image of the smoker may be particularly important for the process of adolescent smoking initiation. With that in mind, the present study had 2 goals: (1) to assess the social image of cigarette smoking among early and middle nonsmoking adolescents, and (2) to determine whether that social image serves to motivate smoking initiation. Based on considerations of self-esteem and susceptibility to social influence, social image factors were predicted to be related to intentions to smoke more for early adolescents and for girls. Results indicated that the social image of both male and female smokers was an ambivalent one for both early and middle adolescents. Smoking models were rated as having many undesirable qualities, but also several social assets. In terms of the relationship of the social image to smoking intentions, early adolescent girls had intentions that were best predicted by the perceived negative qualities of smoking. For middle adolescents, smoking intentions were related to the positive social assets of smoking, especially interest in the opposite sex. These results suggest that prevention strategies for early adolescent girls focus on the negative results of smoking. On the other hand, strategies for middle adolescents should either attack the positive image of the smoker or provide alternative means of self-image improvement.

Adolescent↗
PubMed1981

Antenatal diagnosis of homozygous beta thalassaemia in Mediterraneans in Australia.

Facilities for the antenatal diagnosis of homozygous beta thalassaemia have recently become available in Australia and in this paper, data from a series of 18 pregnancies examined at The Royal Women's Hospital, Melbourne, are analysed. Fetal blood was collected by fetoscopy and adequate samples were obtained in 16 cases (89%). In 5 pregnancies, fetal blood was shown to have a marked reduction in beta globin production (beta/alpha synthesis less than 0.030) and these pregnancies were terminated. Two pregnancies (11%) were lost in the immediate post-fetoscopy period and in a third pregnancy, neonatal death followed premature labour at 26 weeks' gestation. Seven babies were delivered normally at 36-40 weeks' gestation and cord blood studies excluded homozygous thalassaemia in all cases. The remaining pregnancy has yet to be delivered.

Australia↗
PubMed1980

Characteristics of respondents and non-respondents to a mailed questionnaire.

In establishing a cohort of U.S. nurses, an assessment of response bias was made comparing respondents and non-respondents with regard to age, education, state of residence, employment status, field of employment, and major specialty. Overall, the 122,328 respondents (69.7 per cent) and 43,222 non-respondents were quite similar. Together with the reasonable response rate in a homogeneous population, this suggests that estimation of exposure-disease associations is unlikely to be affected by major bias due to non-response.

Adult↗
PubMed1979

F cells in gynaecologic malignancy.

Red cells containing Hb F (F cells) were detected by immunofluorescence using a specific antiserum. In normal persons, the number of F cells was 2.5 +/- 1.1%. A significantly increased number of F cells was found in 65% of patients with cancer of the ovary, 69% of patients with cancer of the endometrium and in 22% of patients with cancer of the cervix. Highest values were obtained in cancer of the ovary and endometrium. There was no correlation between the number of F cells and stage of disease or degree of differentiation. It is postulated that in patients with malignant disease a humoral factor is produced which interferes with normal erythropoiesis resulting in a process of dedifferentiation.

Antibody Formation↗
PubMed1978

Quantitation of globin chains using cellulose acetate electrophoresis: analysis of fetal globin chain production.

A technique involving the quantitative estimation of globin chains using cellulose acetate electrophoresis is described, and applied to the analysis of fetal globin chain production. When cord blood was analyzed, there was poor correlation between the globin chain ratios namely beta/alpha, gamma/alpha and beta/gamma ratios with either age or weight of newborn babies between 36-40 weeks gestation: best correlations were obtained for the beta/gamma ratio against weight (P less than 0.05). However, there was highly significant correlation between the various globin chain ratios and either age or weight of the newborn infant up to 12 weeks of age (P less than 0.001). This technique allows visual demonstration and quantitation of abnormal haemoglobins in a single procedure.

Aging↗
PubMed1978

Coronary vasodilator activity of 13,14-dehydroprostacyclin methyl ester: comparison with prostacyclin and other prostanoids.

The effects of a recently synthesized, stable prostacyclin (PGI2) analog, 13,14-dehydro-PGI2 methyl ester, and authentic PGI2 and several other prostanoids on the coronary circulation were investigated in the intact dog by using a new technique to measure coronary sinus blood flow. The PGI2 analog, PGI2, and prostaglandin (PG) E2 and D2 each increased coronary sinus blood flow in a dose-related fashion when injected into the left coronary artery. The analog and PGE2 had similar vasodilator activity while PGI2 was slightly more potent. PGD2 was a moderately active coronary vasodilator whereas PGF2alpha was inactive. The coronary vasodilator effects of PGI2, its analog, PGE2, and PGD2 occurred at doses that had little effect on aortic pressure, left ventricular pressure and its first derivative, or on cardiac output and heart rate. The prostaglandin precursor arachidonic acid and the endoperoxide intermediate PGH2 both increased coronary sinus blood flow in a dose-dependent manner. The effects of arachidonic acid were inhibited by indomethacin. These data show that PGE2, PGI2, and a stable PGI2 analog are potent vasodilators in the canine coronary vascular bed and suggest that the vasodilator effects of arachidonic acid and PGH2 may be due to the formation of PGE2, PGD2, or PGI2 in the dog heart.

Animals↗
PubMed1978

Analysis of ultrasonographic criteria in the evaluation for ectopic pregnancy.

To assess the usefulness of ultrasound in diagnosing ectopic pregnancy, the ultrasonographic findings, pregnancy test results, and proven diagnoses in 148 patients referred for evaluation for ectopic pregnancy were reviewed. Of these patients, 33 were subsequently proven to have ectopic gestations. The ultrasonograms were coded for uterine size, intrauterine gestation sac, adnexal mass, adnexal ring, cul-de-sac fluid, or normal findings. With a positive pregnancy test, the presence of an intrauterine gestation sac excludes the diagnosis of ectopic pregnancy. Of those patients with positive pregnancy tests and no intrauterine gestation sac, 73% had ectopic pregnancy. All patients with normal ultrasonograms had other diagnoses. With a negative pregnancy test, the intrauterine findings are not helpful, and evaluation of the adnexa is more important. An adnexal ring is a significant, though not absolute, indicator of ectopic pregnancy. A normal scan excludes this diagnosis. Other criteria were not significant. A clinical approach to the evaluation for ectopic pregnancy, based on the data accumulated in this study, is suggested.

Female↗