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Biomedical subjects

A Mackenzie

Publications and source records attributed to A Mackenzie.

At least 37 records · Page 2Linked to original sources
PubMed1996

Attributes of nurses that determine the quality of care for mentally handicapped people in an institution.

This is an ethnographic study that examines, from the relatives' perspective, the attributes of nurses that are considered important in the caring process of mentally handicapped people in an institutional setting in Hong Kong. Twelve interviews were carried out with a family member who had a relative living in a special unit for severely mentally handicapped people. Empirical studies, mainly from the west, have shown that decisions to place a mentally handicapped family member in residential care is a complex process. Family characteristics, the relatives' characteristics as well as the availability of support, have been found to influence decisions about out-of-home placement. Once this decision has been made, a new caring relationship between nurse, family and relative needs to be established. The final categories that emerged from the data show that families have expectations about the nurses' competence and commitment to the job and about their relationships with the client and the family. Consequently quality is judged, not only by the way in which nurses work with the clients, but also by the way in which they work with the family. Implications for practice and education of nurses working with mentally handicapped people and for nursing administration in Hong Kong are discussed.

Anthropology, Cultural↗
PubMed1996

The use of factor analysis for ascertaining patterns of psychopathology in children with intellectual disability.

The Developmental Behaviour Checklist (DBC) was developed to assess psychopathology in children with intellectual disabilities. A cut-off point between "non-cases' and "cases' was determined by comparison of the total scores with psychiatric clinical assessment. This paper describes a method aimed at determining the types of psychiatric problems in those regarded as "cases'. Factor analysis with varimax rotation carried out on a sample of 1093 subjects extracted six factors. Standardized factor scores were calculated for each subject in a community sample (n = 450), and the only or the dominant positive score was determined for each of the "cases'. Over 80% of "cases' could be allotted to one condition. Only a small number had none, or three or more conditions. The same procedure was replicated on a validation sample (n = 448) with even more satisfactory results. Differences in the prevalence of the six conditions by sex, age and level of mental retardation were ascertained. The validity and clinical relevance of this method are discussed.

Adolescent↗
PubMed1995

Phase behaviour of novel phospholipid analogues.

The phase behaviour of phospholipid analogues containing a phosphoramide moiety was investigated using polarized light microscopy. A complex liquid-crystalline polymorphism consisting of lamellar, and normal topology hexagonal and intermediate phases was observed and found to depend on the structure of the phosphoramide headgroup and its methylation. In addition, a lower consolute phase boundary in the micellar solution part of the phase diagram was observed in some systems. The aggregation behaviour of these novel amphiphiles was compared with that of quaternary ammonium and oligo-ethylene oxide amphiphiles.

Amides↗
PubMed1995

Expression, refolding, and autocatalytic proteolytic processing of the interleukin-1 beta-converting enzyme precursor.

The interleukin-1 beta-converting enzyme is a heterodimeric cysteine protease that is produced as a 45-kDa precursor. The full-length precursor form of the enzyme was expressed in Escherichia coli as insoluble inclusion bodies. Following solubilization and refolding of the 45-kDa protein, autoproteolytic conversion to a heterodimeric form containing 10- and 20-kDa subunits was observed. This enzyme had catalytic activity against both natural (interleukin-1 beta precursor) and synthetic peptide substrates. The inclusion of a specific inhibitor (SDZ 223-941) of the converting enzyme in the refolding mixture prevented proteolytic processing to the 10-/20-kDa form. Similarly, refolding under nonreducing conditions also prevented processing. Time course experiments showed that the 10-kDa subunit was released from the 45-kDa precursor before the 20-kDa subunit, implying that the N-terminal portion of the precursor is released last and may play a regulatory role.

Amino Acid Sequence↗
PubMed1995

A prolonged outbreak of exfoliative toxin A-producing Staphylococcus aureus in a newborn nursery.

An outbreak of erythromycin-resistant, exfoliative toxin-producing Staphylococcus aureus infection in a neonatal unit is described. The organism was coagulase positive but staphyloslide negative, and this unusual phenotype facilitated early recognition of the organism in the routine laboratory. In the initial outbreak there were 77 probable or confirmed cases, with a peak attack rate of 66%. Increased infection control measures were put in place and attempts were made to identify a staff carrier. No carriers were found and the major outbreak subsided. Sporadic cases occurred over the following 10 months, until May 1992, when a colonized staffperson was discovered. She was treated and no further cases occurred. The causative organism was subjected to typing by phage, enterobacterial repetitive intergenic consensus sequence polymerase chain reaction, and pulsed-field gel electrophoresis with two separate enzymes. The phage typing and genomic tests confirmed the presence of the same clone in the unit for 9 months. The organism possessed genes encoding exfoliative toxin A as determined by polymerase chain reaction.

Bacterial Toxins↗
PubMed1995

Incidence and pathogenicity of Arcanobacterium haemolyticum during a 2-year study in Ottawa.

Arcanobacterium haemolyticum has been described as a rare cause of systemic invasive disease and is occasionally isolated from throat swabs. We describe a 2-year study of the incidence and clinical features of A. haemolyticus infection in a pediatric and adolescent population. A total of 11,620 throat swabs were examined for A. haemolyticum with use of a locally developed selective medium. Controls (2,241) were healthy students who were recruited from a separate study. A. haemolyticum was isolated from 42 patients, with the maximum incidence in the 15 to 18-year-old age group; in this subset the incidence was 2.5%. There were no isolates of A. haemolyticum found in the healthy controls, and the difference in incidence between patients and controls in the 15 to 18-year-old age group was highly significant (P < .01). Approximately half of the patients infected with A. haemolyticum had a rash. In 5 patients, A. haemolyticum was associated with a positive monospot test. The organism was highly susceptible to erythromycin and less susceptible to penicillin. The evidence from this study suggests that A. haemolyticum may be a pathogen with maximum incidence in the 15 to 18-year-old age group.

Actinomycetaceae↗
PubMed1994

A novel application of microsphere perfusion and scanning electron microscopy to the identification of pulmonary arterioles in guinea-pig and rabbit lungs.

In arterioles of the lung the intravascular blood pressures are lower than in comparable vessels in the systemic circulation and the arteriole walls are thinner. Therefore, it is very difficult to distinguish between arterioles and venules of the same size using scanning electron microscopy. This study describes a novel application of latex microsphere perfusion and scanning electron microscopy which distinguishes between pulmonary arterioles and venules on the basis of endothelial cell morphology. Microspheres, 90 and 45 microns in diameter, were perfused into the arterial side of the pulmonary circulation of guinea-pig and rabbit lungs. Scanning electron microscopy of the arterioles on both sides of the lodged microspheres indicated that the endothelial cells are spindle shaped. In contrast, the endothelial cells of equal diameter venules are polygonal. Furthermore, the nuclei of the arteriolar endothelial cells were significantly (P = 0.019) narrower than those of endothelial cells in venules of equal diameter. Finally, it was observed that the differences between arteriole and venule endothelial cells persisted distally to the capillaries.

Animals↗
PubMed1994

Controlled drinking and abstinence in alcoholic men: beliefs influence actions.

A group of alcoholic men were asked 8 years postdischarge from hospital if they could drink alcohol with control. Subjects who said "no" (the NCD group) were compared to those who said "yes" (the CD group). A majority of the NCD group had been abstinent during the year preceding the 8-year evaluation, whereas none of the CD group had been. In the model developed, troubles resulting from drinking are seen as instrumental in changes from a CD to a NCD belief. The clinical relevance of our results is discussed.

Adult↗
PubMed1993

Measuring the impact of nursing interventions in the community: a selective review of the literature.

In a resource conscious environment, it is imperative that nurses use their skills and knowledge to provide an optimum service. It is suggested that nurses working in the community must measure the impact of their nursing interventions to guide their own role development and to inform the purchasing process. This literature review has revealed, however, that little progress has been made in this area by nurses within the community setting. Indeed, it is suggested that research is needed to test reliable and valid methods of outcome measurement.

Community Health Nursing↗
PubMed1992

The pattern of psychiatric morbidity in a Victorian urban aboriginal general practice population.

Victorian Aboriginal people, most of whom live an urban lifestyle, form a distinct cultural group within the wider Victorian community. This paper describes a unique psychosocial study of urban Aboriginal adults attending a general practitioner at the Victorian Aboriginal Health Service in Fitzroy. The frequency and nature of psychiatric disorders among survey respondents is reported, together with a discussion of the association between this morbidity and certain sociodemographic variables.

Adolescent↗
PubMed1992

Cyclosporin A. Mode of action and effects on bone and joint tissues.

Cyclosporin A is an established immunomodulatory agent with an increasing number of clinical applications. Although its precise mechanisms of action remain elusive, one of the most important known properties of CyA is its ability to inhibit the production of cytokines involved in the regulation of T-cell activation. In particular, CyA inhibits de novo synthesis of interleukin 2(IL-2), the major cytokine involved in T-cell proliferation, as well as other cytokines, probably at the level of gene transcription, as shown by the suppression of mRNA levels in activated T-cells. Although the major actions of CyA are on T-cells, there is some evidence for possible direct effects on other cell types e.g. B-cells, macrophages and, from our own work, on bone and cartilage cells. Cyclosporin A is thought to enter cells and to bind to cyclophilins, which are members of a family of high-affinity cyclosporin A-binding proteins, now known as immunophilins. The binding of cyclosporins to such proteins appears to be closely linked to the immunosuppressive action of cyclosporins. The immunophilins possess enzyme activity, ie. peptidyl-prolyl cis-trans isomerase, also known as rotamase, which can regulate protein folding, and may therefore alter the functional state of many cell proteins. Cyclosporin A blocks peptidyl-prolyl cis-trans isomerase activity but it is not clear whether this plays a part in its selective inhibition of cytokine-gene transcription. Moreover, the ubiquitous presence of cyclophilins and immunophilins raises the question of why cyclosporin A has its apparent major effects only on T-cells. Recent proposals regarding the intracellular mode of action of CyA suggest that it interacts with cyclophilin and other regulatory proteins including calmodulin and calcineurin, which is a serine/threonine phosphatase, and thereby affects the functional state of key regulators of gene transcription in its target cells. The effects of CyA on T-cells and directly or indirectly on connective tissue cells, including bone, cartilage and synovial cells, which all can produce a range of cytokines, are of interest in relation to the tissue changes that occur in inflammatory diseases, such as rheumatoid arthritis. Thus, for example, cyclosporin A inhibits in vitro the bone resorbing activity of interleukin 1, 1,25-dihydroxy-vitamin D3, parathyroid hormone and prostaglandin E2 by apparently non-T-cell effects, while in vivo protects against bone and cartilage loss in adjuvant arthritis. More needs to be known about the direct and indirect modulation of cytokine production by cyclosporin A in connective tissues, in order to understand its potential value in clinical disorders.

Arthritis, Rheumatoid↗
PubMed1991

Randomised controlled trial comparing oral and intravenous rehydration therapy in children with diarrhoea.

OBJECTIVE: To determine the effectiveness of oral rehydration in children with moderate dehydration caused by gastroenteritis, and to compare the complications of oral and intravenous treatment. DESIGN: Randomised controlled trial. SETTING: Emergency department and infectious diseases ward in a large urban teaching hospital. PATIENTS: 111 children aged 3-36 months who had been previously healthy, had had diarrhoea for seven days or less, had clinical signs of dehydration, and were not in shock. Six children were withdrawn because the diagnosis was incorrect (four in oral group, two in intravenous group) and one (oral group) was withdrawn at her parents' request. INTERVENTIONS: Oral rehydration fluid was given by mouth or nasogastric tube, or both to 52 children. The remaining 52 received intravenous rehydration fluids but were allowed to drink. MAIN OUTCOME MEASURES: Success or failure of rehydration. Number of times child vomited or passed stool after starting treatment. Time taken to rehydrate. RESULTS: Oral treatment failed in two children (failure rate 3.8%, upper 95% confidence limit 11.6%) and intravenous treatment in none. Vomiting was more common in the oral group (p less than 0.01): 26 of 50 children (52%) in the oral group and 11 of 50 (22%) in the intravenous group vomited during rehydration. There was no significant difference between the two treatment groups in the number of stools passed during rehydration (p = 0.09). None of the children had serious complications of treatment. CONCLUSION: Rehydration by mouth or nasogastric tube is a safe and effective treatment for moderately dehydrated children with gastroenteritis.

Administration, Oral↗
PubMed1991

The homeobox gene Hox 7.1 has specific regional and temporal expression patterns during early murine craniofacial embryogenesis, especially tooth development in vivo and in vitro.

Hox 7.1 is a murine homeobox-containing gene expressed in a range of neural-crest-derived tissues and areas of putative epithelial-mesenchymal interactions during embryogenesis. We have examined the expression of Hox 7.1 during craniofacial development in the mouse embryo between days 8 and 16 of development. Whereas facial expression at day 10 of gestation is broadly localised in the neural-crest-derived mesenchyme of the medial nasal, lateral nasal, maxillary and mandibular processes, by day 12 expression is restricted to the mesenchyme immediately surrounding the developing tooth germs in the maxillary and mandibular processes. Hox 7.1 expression in the mesenchyme of the dental papilla and follicle is maximal at the cap stage of development and progressively declines in the bell stage prior to differentiation of odontoblasts and ameloblasts. Hox 7.1 expression in tooth germs is independent of overall embryonic stage of development but is dependent on stage of development of the individual tooth. Similar patterns of transient Hox 7.1 expression can also be detected in tooth germs in vitro in organ cultures of day 11 first branchial arch explants cultured for up to 7 days. Hox 7.1 is also expressed early in development (days 10/11) in the epithelium of the developing anterior pituitary (Rathke's pouch), the connective tissue capsule and meninges of the developing brain, and specific regions of neuroepithelium in the developing brain.

Animals↗
PubMed1990

Characterization of ent-kaurene oxidase activity from Gibberella fujikuroi.

Cell extracts of wild-type and mutant strains of Gibberella fujikuroi were assayed for kaurene oxidase activity, using ent-[3H]kaurene as the substrate. Extracts from strain SG78 exhibited the highest specific activity, and were used in subsequent experiments. The microsomal enzyme activity was solubilized with buffers or salt solutions at a concentration of 400 mM. Both the soluble and microsomal preparations showed characteristic cytochrome P-450 spectra, ligand binding spectra with the substrate and with the plant growth regulator, paclobutrazol, and inhibition of enzymic activity by carbon monoxide. The addition of 20% glycerol to the extraction buffer stabilized the activity to some extent. Loss of enzymic activity on storage was accompanied by conversion of P-450 to P-420. Michaelis-Menten kinetic parameters for the membrane-bound and soluble enzyme have been estimated, as have constants for the binding of ent-kaurene and paclobutrazol to the P-450 and P-420 forms of the protein.

Cytochrome P-450 Enzyme System↗