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Biomedical subjects

M R Johnson

Publications and source records attributed to M R Johnson.

At least 253 records · Page 14Linked to original sources
PubMed1986

Medical teaching of the cultural aspects of ethnic minorities: does it exist?

The development of published material relating to the practice of medicine in multiracial and multicultural Britain is briefly reviewed. The utilization of such information in English medical schools is found to be absent or at a low level of priority. A more detailed study of one region demonstrates that junior hospital doctors believe from experience that they have a need for training in 'multicultural' medicine to serve their current patient load. Objective tests demonstrate the poor levels of knowledge and the role of practical experience. Responses from a survey of administrators and clinical tutors suggest interest or willingness to develop training in this field but a lack of coordination or resources. The paper demonstrates clearly that medical education has failed to keep pace with developments in the social and ethnic composition of the potential client population. Doctors who are practising in multiracial areas support this argument for changes in the undergraduate curriculum and extension of provision in postgraduate education. These improvements should not be confined to specific medical schools because of the career mobility of doctors, and by analogy could be extended to other medical professionals. Recommendations are made as a basis for a long-term strategy to ensure that medical education plays its part in combating racism in society.

Asia↗
PubMed1986

Tripartite sequences within and 3' to the sea urchin H2A histone gene display properties associated with a transcriptional termination process.

We have defined a DNA sequence that behaves as an RNA polymerase II termination signal by using the human HeLa cell transient expression system. Surprisingly, this sequence is tripartite, including part of the coding region of the sea urchin H2A histone gene together with two separate sequences in the 3' flanking region of the gene. We demonstrate that this signal functions both in its normal gene environment and also when placed within the human alpha-globin gene. However, we have failed to detect a discrete 3' terminus. Rather, our data indicate the presence of an extremely heterogeneous series of nonpolyadenylated RNAs. These heterogeneous nonpolyadenylated RNAs are stable when transcribed from the intact histone gene but are highly unstable within the human alpha-globin gene. This provides evidence for the role of poly(A) in the stability of mRNA.

Animals↗
PubMed1986

Changes in cross-sectional area of the coronary lumen in the six months after angioplasty: a quantitative analysis of the variable response to percutaneous transluminal angioplasty.

Although immediate and late changes in coronary stenoses after percutaneous transluminal coronary angioplasty (PTCA) have been reported, most investigators have employed qualitative or semiquantitative techniques to analyze the angiograms. Such data is not optimal because of considerable interobserver variability and the use of relative instead of absolute changes in lesion geometry. Analysis is further compounded by the indistinct edges that characterize coronary lesions immediately after angioplasty. To quantify the changes in minimal cross-sectional area (MCSA) of the coronary lumen that occur during and after PTCA, we analyzed the angiograms of 23 patients before PTCA, immediately after PTCA, and at 7.2 +/- 3.0 (mean +/- SD) months follow-up using two computer-assisted methods of angiographic analysis--quantitative coronary angiography (QCA) and videodensitometry (VID). QCA provides an absolute measure of the area of the lumen; VID is a nongeometric method that is not dependent on exact border recognition. Based on these quantitative methods, we found that successful angioplasty is associated with about a three-fold increase in the MCSA of the lesion (from 1.0 to 3.2 mm2). This area is, however, well below normal and is less than half of the average MCSA of the inflated dilating balloon. Analysis of follow-up angiograms demonstrated that eight of 23 patients had a substantial late increase in the MCSA of the lesion (from 2.7 to 4.1 mm2) after the angioplasty procedure. Clinical, hemodynamic, and angiographic characteristics immediately after PTCA were not predictive of MCSA of the lumen at follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1986

Paradoxical cerebral embolism: eight cases.

We evaluated eight patients with possible or probable paradoxical cerebral embolism. One patient had a hemispheric transient ischemic attack; the others had infarcts. Ischemic symptoms followed a Valsalva's maneuver in three cases. Others were linked to placement of a Swan-Ganz catheter, deep venous thrombosis and pulmonary embolism, right atrial myxoma, and use of oral contraceptives. Four had no known predisposing conditions. In six patients, contrast echocardiography showed right-to-left shunting. Cardiac catheterization showed a patent foramen ovale in three patients; one had an atrial septal defect. In the clinical setting of otherwise unexplained cerebral embolism in a young patient, paradoxical cerebral embolism should be considered. Contrast echocardiography is a useful screening test for this purpose.

Adolescent↗
PubMed1985

Enhancement of brain [3H]flunitrazepam binding and analgesic activity of synthetic cannabimimetics.

Novel, synthetic cannabimimetics and delta 9-tetrahydrocannabinol were found to enhance the binding of [3H]flunitrazepam to mouse brain in vivo. This property, suggestive of facilitation of binding to benzodiazepine receptors, is consistent with the potentiation of the anticonvulsant activity of diazepam against pentylenetetrazol by these compounds. The relative potencies of delta 9-tetrahydrocannabinol and the new cannabimimetics for enhancing [3H]flunitrazepam binding in vivo could also be correlated with their relative analgesic efficacies. Similar pharmacological stereospecificity was displayed for both binding enhancement and analgesic effects. The following order of decreasing potency was observed: N-methyllevonantradol and (-)-CP-55,244 greater than levonantradol, canbisol, CP-42,096 and (-)-CP-55,940 greater than 9-beta-normethyl-9-beta-hydroxyhexahydrocannabinol, nabilone and CP-47,497 greater than delta 9-tetrahydrocannabinol. Dextronantradol, (+)-CP-55,940 and (+)-CP-55,244 were considerably less active than the respective (-)-enantiomers; cannabidiol was inactive. Extensive investigation of structure versus activity led to N-methyllevonantradol and the 3-(2-hydroxyphenyl)cyclohexanols derivative, (-)-CP-55,244, which are approximately 1000-fold more potent than delta 9-tetrahydrocannabinol.

Analgesics↗
PubMed1985

Special diagnostic tests and procedures.

The purpose of this article is to provide the physical therapist with a clinically useful description of diagnostic tests commonly used for patients in cardiac rehabilitation. I reviewed five diagnostic tests: coronary angiography, thallium 201 myocardial perfusion imaging, radionuclide ventriculography, echocardiography, and Holter monitoring. The procedural techniques, indications, diagnostic capabilities, limitations, and comparisons of these tests are discussed. I present the applicability of these tests relative to the therapist's roles as clinician, educator, and cardiac rehabilitation team member.

Coronary Angiography↗
PubMed1984

Perseveration of attention to conspecific odors and novel objects in castrated gerbils.

Castrated male and female gerbils were tested for odor preference and for attention to conspecific odors and a novel object. Castrated gerbils housed with sham-operates preferred home odors, discriminated between two groups of male gerbils by olfactory cues, and perseverated in attention to odors of male gerbils and to a novel object. Similar perseveration to male conspecific odors was shown in gerbils given injections of L-DOPA (30 mg/kg). Combined treatment (castration and L-DOPA) resulted in additive effects on perseveration. This research challenges two general hypotheses of gonadal hormone function. The first, that changes in odor preference after castration are due to a loss in testicular androgen, is insufficient, because (1) female as well as male gerbils showed similar perseveration to odors, (2) there was a significant correlation between LH and duration of investigation of male conspecific odors, and (3) L-DOPA, the dopamine precurser, also caused perseveration to conspecific odors. The second, that gonadal hormones are responsible for persistence of attention, cannot be broadly generalized, because castration with resultant elevation of LH and regression of ventral glands resulted in perseveration of attention in male and female gerbils.

Animals↗
PubMed1984

A cannabinoid derived prototypical analgesic.

The synthesis and analgesic testing of 3-[4-(1,1-dimethylheptyl)-2-hydroxyphenyl]cyclohexanol (1) are described. Prior (SAR) studies led us to conclude that the pyran ring of 9-nor-9 beta-hydroxyhexahydrocannabinol (HHC) was not necessary for the expression of biological activity in this series of cannabinoids. Analysis of models and the use of molecular mechanics calculations suggested that a simpler compound, such as 1, would possess the biological activity of HHC. Compound 1 was prepared in nine steps from [3-(benzyloxy)phenyl]acetonitrile (2). Biological testing in five models of pain shows that compound 1 and morphine are equally potent as analgesics and demonstrates that the pyran ring of HHC is not necessary for biological activity. Further simplification of 1 was pursued by the synthesis of 4-[4-(1,1-dimethylheptyl)-2-hydroxyphenyl]-2-pentanol (17), but this derivative exhibits significantly reduced analgesic activity.

Analgesics↗
PubMed1983

The musculature and pupillary response of the great horned owl iris.

There is considerable confusion in the literature regarding the nature of the musculature of the avian iris. The most commonly held view is that both the sphincter and dilator are striated. The iris of the Great Horned Owl (Bubo virginianus) has a complex iridial musculature consisting of three circumferential components (a myoepithelium, smooth muscle and striated muscle) and two radial components (a well-developed myoepithelium and a few striated fibers). On the basis of the anatomy and relative development of these components, and a quantitative analysis of the pupillary reflex, it is proposed that the circumferential striated muscle is the primary pupillary constrictor and radial myoepithelium is the primary dilator. The annular band of smooth muscle may play an important role in maintaining pupillary size.

Animals↗
PubMed1983

Structure-activity studies of configurationally rigid arylprostaglandins.

Potent, albeit nonselective, smooth-muscle stimulant activity has been previously reported for 16-phenoxy- and 17-phenylprostaglandins, a finding that led to the design and development of the tissue-selective uterine stimulant sulprostone. As an extension of this work, analogues incorporating the 16-phenoxy and 17-phenyl substituents into the rigid indanyl, tetrahydronaphthyl, dihydrobenzofuryl, and dihydrobenzopyranyl ring systems were prepared and evaluated for uterine stimulant activity in vitro and diarrheal effects in vivo. Since these cyclic groups, with the exception of the indanyl, contain a chiral center, both optical antipodes were prepared. These studies demonstrate that ring size, heteroatom, and absolute configuration at C-16 are important determinants for potency and selectivity.

Abortion, Induced↗
PubMed1983

The development of smoking during adolescence--the MRC/Derbyshire Smoking Study.

Each year from 1974, when they entered secondary school, to 1978, when they reached school-leaving age, a cohort of over 6000 schoolchildren from Derbyshire, England, answered a questionnaire about their own and their family's smoking practices and their social activities. Their replies revealed a steady increase in the prevalence of smoking during adolescence. Those children who in 1974 smoked, had friends of the opposite sex, were highly involved in social activities, experienced peer pressure to smoke and rejected the health hazards of smoking were more likely to be regular smokers in 1978 than were other children. Similarly, those children who, when aged 11-12 years, had parents or siblings who smoked, had friends of the opposite sex, and were highly involved in social activities increased their smoking rapidly in subsequent years. Sex and social class differences in the strength of these associations suggest that an understanding of the development of smoking during adolescence requires knowledge of the particular character of the social relationships among different subgroups of that age-group and the various meanings of smoking to them.

Adolescent↗
PubMed1983

Inner-city residents, ethnic minorities and primary health care.

Ethnic minorities form a substantial proportion of the urban population. A household survey in the West Midlands assessed usage of primary and preventative health care services. Asian households made some-what higher use of general practitioner (GP) facilities which can be related to demographic and socio-economic status. Fewer differences were found than expected, and uptake of preventative services was good. Afro-Caribbean patterns were similar to those of whites.

Adolescent↗