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Biomedical subjects

M Wilson

Publications and source records attributed to M Wilson.

At least 91 records · Page 5Linked to original sources
PubMed2001

How to obtain uniformity of occlusal detail.

At a recent Primary Dental Care Editorial Board meeting it was suggested that a series of short articles providing practical advice on clinical procedures might well be appreciated by our readers. This, then, is an invitation to our readers to submit material of this type, for publication. The text may be kept brief by the use of illustrations. The following example is the type of communication that we have in mind, but any information of a practical nature about the use of dental products would be carefully considered. We are grateful to the publishers of Fenestra (3M Dental Products) and the authors for permission to republish this piece first published in 1999.

Dental Impression Materials↗
PubMed2001

Vertex/propagator model for least-scattered photons traversing a turbid medium.

The least-scattered photons that arrive at a detector through highly scattering tissues have the potential to image internal structures, functions, and status with high imaging resolution. In contrast, optical diffusing tomography is based on the use of the late-arriving photons, which have been diffusely scattered, leading to very low imaging resolution. A good model of the early-arriving photons, i.e., the least-scattered photons, may have a significant effect on the development of imaging algorithms and a further understanding of imaging mechanisms within current high-resolution optical-imaging techniques. We describe a vertex/propagator approach that attempts to find the probabilities for least-scattered photons traversing a scattering medium, based on analytical expressions for photon histories. The basic mathematical derivations for the model are outlined, and the results are discussed and found to be in very good agreement with those from the Monte Carlo simulations.

Journal Article↗
PubMed2001

Antibodies anti-Chlamydia pneumoniae and anti-Mycoplasma pneumoniae in patients with negative serology for hantavirus. Retrospective study.

The seroprevalence of Chlamydia pneumoniae and Mycoplasma pneumoniae in hantavirus seronegative patients, who had symptoms and signs compatible with pneumonia was established. For this purpose we used the indirect fluorescent antibody test. Titers > or = 1:16 for C. pneumoniae and M. pneumoniae were found in 8.6% and 17.1% of the serum, respectively, showing evidence of recent or current infection.

Adolescent↗
PubMed2001

Bacterial biofilms and human disease.

The term biofilm is used to denote a polymer-encased community of microbes which accumulates at a surface. Biofilms are responsible for a number of diseases of man and, because of the intrinsic resistance of these structures to antibiotics and host defence systems, such diseases are very difficult to treat effectively. The application of new microscopic and molecular techniques to biofilms has revolutionised our understanding of their structure, composition, organisation and activities. This review will describe the role that biofilms play in human disease and will outline our new millennial view of these complex and fascinating bacterial communities.

Antibiotic Prophylaxis↗
PubMed2001

The case for sensorimotor coding in working memory.

The highly influential Baddeley and Hitch model of working memory (Baddeley & Hitch, 1974; see also Baddeley, 1986) posited analogical forms of representation that can be broadly characterized as sensorimotor, both for verbal and for visuospatial material. However, difficulties with the model of verbal working memory in particular have led investigators to develop alternative models that avoid appealing either to sensory coding or to motoric coding, or to both. This paper examines the evidence for sensorimotor coding in working memory, including evidence from neuropsychology and from sign language research, as well as from standard working memory paradigms, and concludes that only a sensorimotor model can accommodate the broad range of effects that characterize verbal working memory. In addition, several findings that have been considered to speak against sensorimotor involvement are reexamined and are argued to be in fact compatible with sensorimotor coding. These conclusions have broad implications, in that they support the emerging theoretical viewpoint of embodied cognition.

Attention↗
PubMed2001

Primary care physician job satisfaction and turnover.

OBJECTIVE: To examine the relationship of personal characteristics, organizational characteristics, and overall job satisfaction to primary care physician (PCP) turnover. SUBJECTS AND METHODS: A cohort of 507 postresident, nonfederally employed PCPs younger than 45 years of age, who completed their medical training between 1982 and 1985, participated in national surveys in 1987 and 1991. Psychological, economic, and sociological theories and constructs provided a conceptual framework. Primary care physician personal, organizational, and overall job satisfaction variables from 1987 were considered independent variables. Turnover-related responses from 1991 were dependent variables. Bivariate and multivariate analyses were conducted. RESULTS: More than half (55%) of all PCPs in the cohort left at least 1 practice between 1987 and 1991. Twenty percent of the cohort left 2 employers. PCPs dissatisfied in 1987 were 2.38 times more likely to leave (P < .001). Primary care physicians who believed that third-party payer influence would decrease in 5 years were 1.29 times more likely to leave (P < .03). Non-board certified PCPs were 1.3 times more likely to leave (P < .003). Primary care physicians who believed that standardized protocols were overused were 1.18 times more likely to leave (P < .05). Specialty, gender, age, race, and practice setting were not associated with PCP turnover. CONCLUSIONS: Turnover was an important phenomenon among PCPs in this cohort. The results of this study could enable policy makers, managed care organizations, researchers, and others to better understand the relationship between job satisfaction and turnover.

Adult↗
PubMed2001

Pituitary-adrenal function in uncomplicated falciparum malaria.

To investigate pituitary-adrenal function in acute uncomplicated falciparum malaria, we performed an overnight dexamethasone suppression test in 13 Vietnamese adults with acute malaria and 6 healthy controls. After blood samples were taken for serum cortisol and plasma ACTH at 23.00 hours on the admission day, 1 mg dexamethasone was given and further samples were taken at 08.00, 16.00 and 23.00 hours the next day. The patients received conventional antimalarial and supportive treatment. Baseline plasma ACTH concentrations in the patients [3.9 (0.2-41.2) pmol/l] and controls [3.4 (1.1-4.3) pmol/l] were similar (p=0.51), and exhibited a similar fall after dexamethasone to 0.6 (0.2-2.5) and 0.9 (0.7-1.6) pmol/l at 08.00 hours respectively (p<0.03 vs 23.00 hour values). Serum cortisol levels before dexamethasone were higher in the patients than in the controls [456 (102-821) vs 145 (64-183) nmol/l respectively; p=0.007] and the overnight fall was less in the patients [208 (26-340) and 23 (15-46) nmol/l at 08.00 hours respectively; p<0.001 vs 23.00 hour values and between groups]. Between 08.00 and 23.00 hours, plasma ACTH and serum cortisol remained suppressed in the controls. In the patients, the serum cortisol continued to fall progressively towards control values. These data suggest that there is a raised set point for cortisol inhibition of ACTH secretion but normal corticotrophin responsiveness to dexamethasone in uncomplicated malaria. A raised serum cortisol after dexamethasone in the patients might reflect the combination of a prolonged cortisol half-life and the stimulatory effects of cytokines on the adrenal cortex, with a consequent protective effect against complications such as hypoglycemia.

Adrenal Glands↗
PubMed2000

Enhanced surveillance of HIV infections in New Zealand, 1996-1998.

AIM: To improve understanding of the HIV epidemic in New Zealand through use of an enhanced voluntary reporting system for new diagnoses of HIV. METHODS: Routine reporting of new HIV diagnoses by the two laboratories that perform confirmatory HIV antibody testing, to the Department of Health and later to the AIDS Epidemiology Group, has been in place since 1985. From January 1996, this was supplemented by a questionnaire about demographic characteristics and circumstances of HIV exposure sent to clinicians requesting the HIV test. RESULTS: From January 1996 to December 1998, 260 new diagnoses of HIV were reported (205 males, 55 females) and extra information was obtained from clinicians for 253 (97.3%) people. HIV diagnosis rate was highest for 'other' ethnicity and similar for European, Maori and Pacific Island ethnic groups. Sexual intercourse between men was the commonest mode of infection (43.5%), followed by heterosexual intercourse (40.0%) and injecting drug use (2.7%). Places of infection were New Zealand (38.5%), Australia (7.7%), 'other' overseas (45.4%) and unknown (8.5%). Heterosexual infections were acquired through contact with a person in or from a high prevalence area (mainly in Africa or Asia) for 86.7% of males and 68.2% of females. Second generation heterosexual transmission was rare. CONCLUSIONS: Introduction of an enhanced surveillance system has been successful. Results confirm continuing spread of HIV in New Zealand amongst men who have sex with men, and suggest low levels of heterosexual and injecting drug use transmission in New Zealand. Of major importance in the occurrence of heterosexual infection is the role of imported HIV.

Adolescent↗
PubMed2000

Structural studies of microcosm dental plaques grown under different nutritional conditions.

The aim of this study was to investigate the structure of intact oral biofilms using confocal laser scanning microscopy (CLSM). Mixed-species biofilms were grown on enamel discs in a constant depth film fermentor. The biofilms were fed with a mucin-containing artificial saliva with or without sucrose supplementation. Biofilms were examined using a Wild-Leitz CLSM, operating in reflected light mode. The microstructure of non-supplemented biofilms was revealed to be complex, with stacks of bacteria developing over time, separated by clear channels. Sucrose-supplemented biofilms appeared to colonise the substratum more rapidly. The results of this study have shown that using CLSM it is possible to examine the structure of oral biofilms grown under conditions similar to those which would exist in vivo.

Biofilms↗
PubMed2000

Detecting mannosidase activities using ribonuclease B and matrix-assisted laser desorption/ionization-time of flight mass spectrometry.

Ribonuclease (RNase) B incubated with purified enzymes, whole bacterial cultures, or their separated components-cells and supernates-have been directly analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-ToF) to detect exomannosidases and to evaluate their specificities and location. Enzymatic cleavage was monitored by observing changes in RNase B glycoform population. Thus a nonspecific alpha-(1 --> 2)-mannosidase activity converts the glycoprotein to its Man(5) form, identifiable by its mass of 14,899 [M + H](+); this species subsequently is converted, by the actions of alpha-(1 --> 3) and alpha-(1 --> 6)-mannosidases, to the Man(1) form via Man(4), Man(3), and Man(2). The Man(1) glycoform (which is readily isolated) has then similarly been used for identifying beta-(1 --> 4)-mannosidase and the derived Man(0) form has served in turn as a natural substrate for beta-(1 --> 4) N-acetylglucosaminidase producing a species possessing a single asparagine-linked GlcNAc residue (mass 13,886). Mannose liberated from the actions of mannosidases can, if desired, be quantified by, for example, chromatography. The actions and specificities of endoglycosidases such as a peptide-N-glycosidase F (PNGase F) and of endo-N-acetlyglucosaminidases (e.g., endo-F and endo-H), which respectively cleave between the GlcNAc&bond;Asn and GlcNAc&bond;GlcNAc bonds of N-linked glycoproteins, are also demonstrable by MALDI-ToF analysis of RNase B (and derived products). From these digests the completely deglycosylated polypeptide corresponding to RNase A in which Asn has been converted to Asp (mass 13,684) and a species corresponding to RNase A + GlcNAc (mass 13,886) are produced, together with their corresponding free oligosaccharides which are amenable to analysis by both MALDI-ToF and by HPLC.

Amidohydrolases↗
PubMed2000

Oral contraceptives and fatal pulmonary embolism.

In a national case-control study of fatal pulmonary embolism in New Zealand women of childbearing age, we estimated that current users of combined oral contraceptives had a relative risk of 9.6 (95% CI 3.1-29.1). From national distribution data, the absolute risk of death from pulmonary embolism in current users was estimated to be 10.5 per million woman-years.

Adult↗
PubMed2000

Imperforate anus in Feingold syndrome.

A father and daughter had the characteristic findings of Feingold syndrome including microcephaly, short palpebral fissures, brachydactyly with clinodactyly of fifth fingers, and bilateral syndactyly of second to third and fourth to fifth toes. The infant presented with long-gap esophageal atresia without fistula (type A). Her father, who had short stature and learning disabilities, had congenital imperforate anus with a recto-vesical fistula. This is the first report of distal intestinal atresia in Feingold syndrome.

Abnormalities, Multiple↗