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Biomedical subjects

J G Munro

Publications and source records attributed to J G Munro.

14 recordsLinked to original sources
PubMed1999

Correlated atomic force and transmission electron microscopy of nanotubular structures in pulmonary surfactant.

Pulmonary surfactant stabilizes the lung by reducing surface tension at the air-water interface of the alveoli. Surfactant is present in the lung in a number of morphological forms, including tubular myelin (TM). TM is composed of unusual 40 x 40 nm square elongated proteolipid tubes. Atomic force microscopy (AFM) was performed on polymer-embedded Lowicryl and London Resin-White (LR-White) unstained thin sections. AFM was used in imaging regions of the sections where TM was detected by transmission electron microscopy (EM) of corresponding stained sections. Tapping- and contact-mode AFM imaging of the unstained sections containing TM indicated a highly heterogeneous surface topography with height variations ranging from 10 to 100 nm. In tapping-mode AFM, tubular myelin was seen as hemispherical protrusions of 30-70 nm in diameter, with vertical dimensions of 5-8 nm. In contact-mode AFM and with phase imaging using a sharper (>10 nm nominal radius) probe, square open-ended tubes which resembled typical electron micrographs of such regions were observed. The cross-hatch structures observed inside the tubes using EM were not observed using AFM, although certain multilobe structures and topographic heterogeneity were detected inside some tubes. Other regions of multilamellar bodies and some regions where such bilayer lamella appear to fuse with the tubes were found in association with TM using AFM. EM of acetone-delipidated tubes in LR-White revealed rectangular tubular cores containing cross-hatched structures, presumably protein skeletons. AFM surface topography of these regions showed hollow depressions at positions at which the protein was anticipated instead of the protrusions seen in the lipid-containing sections. Gold-labeled antibody to surfactant protein A was found associated somewhat randomly within the regions containing the protein skeletons. The topography of the gold particles was observed as sharp peaks in contact-mode AFM. This study suggests a method for unambiguous detection of three-dimensional nanotubes present in low abundance in a biological macromolecular complex. Only limited detection of proteins and lipids in surfaces of embedded tubular myelin was possible. EM and AFM imaging of such unusual biological structures may suggest unique lipid-protein associations and arrangements in three dimensions.

Acetone↗
PubMed1999

SP-B refining of pulmonary surfactant phospholipid films.

Pulmonary surfactant stabilizes the alveoli by lining the air-fluid interface with films that reduce surface tension to near 0 mN/m (gamma(min)). Surfactant protein B (SP-B) enhances the surface activity of surfactant phospholipids. A captive bubble tensiometer (CBT) was used to study the properties of adsorbed films of dipalmitoylphosphatidylcholine (DPPC) with acidic 1-palmitoyl-2-oleoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (POPG) or neutral 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphocholine with (7:3) and without 1% dimeric SP-B. SP-B enhanced the adsorption rate of DPPC-containing neutral or acidic lipid suspensions (1 mg/ml) to a similar extent. Quasi-static cycling of these films revealed that SP-B significantly decreased the film area reduction required to reach gamma(min) for the acidic but not for the neutral system. The results obtained with DPPC-phosphatidylglycerol (PG)-SP-B were consistent with selective DPPC adsorption into the surface monolayer during film formation. Film area reduction required to reach gamma(min) with this system (with and without calcium) approached that of pure DPPC, suggesting selective DPPC insertion and PG squeeze-out. Dynamic cycling of such films showed that larger film area reductions were required to reach gamma(min) for the neutral than for acidic system, even after 20 cycles. Fluorescence microscopy of solvent-spread DPPC-POPG-SP-B planar films revealed highly condensed structures at approximately 25 mN/m, although no specific PG phase-segregated structures could be identified. The study suggests that specific interactions of SP-B with acidic phospholipids of surfactant may be involved in the generation and maintenance of DPPC-rich films in the alveoli.

Adsorption↗
PubMed1989

Self-medication among secondary school pupils in Hong Kong: a descriptive study.

A self-completion questionnaire was used to survey self-medication among secondary school pupils in Hong Kong. Data were collected from 4793 pupils aged 10 to 23 years (55.9% female and 44.1% male). Nearly three quarters (72.1%) had taken self-medication without consulting a medical practitioner and 51.8% of the sample had done so without the knowledge of older family members. The prevalence of self-medication increased with age. More than half the pupils (50.4%) indicated that trivial illness did not warrant a consultation with a doctor. Information relating to the sources of self-administered drugs, types of drugs used and sources of information about these drugs was collected. Medicine cabinets at home and pharmacy shops were the two most common places from which the pupils obtained their drugs. Though the prevalence of taking tranquillizers and sleeping tablets was found to be low, the probability of young people, especially boys, obtaining dangerous drugs from these places should not be overlooked. The medical, nursing and teaching professions should take a more active role in health education, as the sources from which the pupils obtained their drug knowledge, in descending order of frequency, were: family members, previous illness experience, pharmacy shops, doctor or nurse, television or radio, newspapers or magazines, friends and teachers.

Adolescent↗
PubMed1984

Computer analysis of the student log diary: an aid in the teaching of general practice and family medicine.

At the University of Queensland all medical students in their fifth year rotate through a 2-week attachment to a general practitioner tutor as part of the course in community practice. As a means of learning from this experience each student records information in a log diary on seventy-five consecutive patients seen, and codes it using a code-book developed for the purpose. The International Classification of Health Problems in Primary Care (ICHPPC) classification is used for coding diagnoses and problems. These data are then computerized and a print-out of frequencies. including mean values, is provided for each student in a group of twenty-eight to thirty. In a teaching session of 2-3 hours held with the group. Results are presented and each variable discussed in turn. Students can easily identify differences between practices, and how data from each practice compare with mean values for the practices visited by the group. Possible reasons for these differences are then discussed. Comparisons are made with similar data accumulated by the Department over 2 1/2 years (amounting to some 42,000 patient encounters), and with other surveys of general practice morbidity. The use of the computer print-out provides an extremely valuable yet comparatively simple method of demonstrating the demography, clinical content and process of general practice.

Australia↗
PubMed1984

The dexamethasone suppression test in residual schizophrenia with depression.

The authors administered the Carroll rating scale for depression to 100 patients with residual schizophrenia and found that 41 were also depressed. Of these 41 patients, 23 were given a dexamethasone suppression test; 7 (31%) failed to suppress cortisol. A matched control group, i.e., 23 patients with residual schizophrenia but without depression, suppressed cortisol normally after taking dexamethasone. The authors found no clinical differences between depressed patients with normal DST results and depressed patients with abnormal DST results.

Adolescent↗
PubMed1982

Measles. The GP view.

Measles is still a common disease in Australia and causes significant morbidity both in itself and in its complications. Dr Clarke Munro discusses the clinical features and management. Although measles can now be prevented by vaccination, immunisation rates remain disappointingly low.

Australia↗
PubMed1980

Determination of aims for an undergraduate general practitioner apprenticeship.

This study was undertaken to clarify the goals of the clinical general practitioner attachment scheme at the University of Queensland. Emphasis was placed on comparing the aims of the academics, the general practitioner preceptors and the students. Prior to the 2-week attachments students selected a different set of goals from those selected by academics and preceptors as most important. However, after the apprenticeship the students changed the goals in the direction of the preceptors'. Students' rating of the perceived level of achievement of the goals showed that the degree of correspondence between goals set by University teachers, preceptors and students was a good predictor of a successful learning experience. This study further suggests that teaching of Community Practice should not rest solely on apprenticeship schemes since preceptors' aims will largely determine the material learnt in the placement to the exclusion of more innovative academic goals.

Australia↗
PubMed1980

Voluntary attachments of preclinical medical students to rural practitioners in Queensland.

This study evaluates the attachment of preclinical medical students to rural general practitioners in Queensland. The expectations of participating students were assessed before the experience, and compared with their realizations. Perceptions of their own clinical skills, and the type of medicine they want to practise were assessed both before and after. Doctors taking part felt stimulated by the experience, and confimed that the presence of a student is readily accepted by patients, and causes minimal practice disruption. Students saw this attachment as providing motivation for their further studies, and relevance to their preclinical work. Clinical sophistication would not appear to be necessary for considerable benefit to be derived from the experience.

Attitude of Health Personnel↗
PubMed1980

Attitudes of medical practitioners towards abortion: a Queensland study.

Sixty-seven per cent of medical practitioners registered in Queensland responded to a survey on their attitudes to the laws relating to abortion and sterilization in that State. Of all respondents, 79 per cent wanted some degree of liberalization of abortion laws. Personal characteristics such as age, sex and religion practised (if any) were found to influence doctors' opinions. Practice characteristics also influenced opinions; general practitioners were more in favour of liberalization than were specialists, and self-employed doctors were more in favour than were doctors working in hospitals or other institutional settings.

Abortion, Legal↗
PubMed1980

Obstetric practice amongst Queensland general practitioners: a survey of needs and attitudes.

A survey of Queensland general practitioners was carried out to assess their needs and attitudes regarding obstetric practice. Less than half of the respondents now practise obstetrics, and many general practitioners felt a lack of support from specialist obstetricians, paediatricians, and anaesthetists. Many of the respondents expressed needs for further obstetric training, especially in labour ward management and neonatal care; however, few were able to attend extended courses.

Adult↗