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Biomedical subjects

M J Wilkins

Publications and source records attributed to M J Wilkins.

15 recordsLinked to original sources

Mycobacterium bovis (bovine TB) exposure as a recreational risk for hunters: results of a Michigan Hunter Survey, 2001.

SETTING: Tuberculosis caused by Mycobacterium bovis (bovine TB) is endemic in the white-tailed deer population of north-eastern Michigan. Hunters may be exposed to M. bovis via cutaneous inoculation while field dressing deer or by ingestion of undercooked venison. Michigan hunters have received inconsistent messages about their risk of acquiring tuberculosis from recreational exposure to deer. The most common health advice offered has been to wear gloves while field dressing deer and to cook venison products thoroughly. OBJECTIVE: Data were collected to quantify these self-protective activities and to characterize hunters practicing these activities. DESIGN: In 2001, we surveyed 1833 hunters who had successfully harvested deer in or near Michigan's bovine TB endemic area in 2000. RESULTS: The survey response rate was 78%. Most hunters (89%) reported field dressing deer, 43% of whom wore gloves. Most hunters (95%) reported eating venison, 55% of whom reported their venison was always cooked thoroughly. Several hunter characteristics, including older age, female sex, higher awareness level, and area of residence, were significantly associated with the practice of these self-protective activities. CONCLUSION: The survey results suggest that hunters should receive consistent advice encouraging glove use while field dressing deer and the thorough cooking of venison products before consumption.

Adolescent↗

Human salmonellosis associated with young poultry from a contaminated hatchery in Michigan and the resulting public health interventions, 1999 and 2000.

Although approximately 95% of disease caused by nontyphoidal salmonella is transmitted by foodborne vehicles, four documented salmonella outbreaks in the 1990s have been traced to contact with young poultry. No environmental studies of source hatcheries were completed. This case-control study was performed by comparing culture-confirmed Salmonella Infantis in Michigan residents, identified between May and July 1999, with two age- and neighbourhood-matched controls. Eighty environmental and bird tissue samples were collected from an implicated hatchery; all salmonella isolates underwent pulsed-field gel electrophoresis (PFGE) analysis. The study included 19 case-patients sharing the same PFGE subtype and 37 matched controls. Within 5 days before illness onset, 74% of case-patients resided in households raising young poultry compared with 16% of controls (matched OR 19.5; 95% CI 2.9, 378.1). Eight hatchery samples yielded Salmonella Infantis with PFGE subtypes matching the patients' isolates. This investigation identified birds from a single hatchery as the source of human illness and confirmed the link by matching PFGE patterns from humans, birds and the hatchery environment. Subsequent public health interventions reduced, but did not eliminate, transmission of poultry-associated salmonellosis. Five additional PFGE-linked cases were identified in Spring 2000, necessitating quarantine of the hatchery for depopulation, cleaning and disinfection.

Adolescent↗

An in situ dissolution study of aspirin crystal planes (100) and (001) by atomic force microscopy.

PURPOSE: To observe in situ and on individual aspirin crystal faces the comparative rates and processes of dissolution of the dominant faces. METHODS: The kinetics of the dissolution rate of two aspirin crystal planes (001) and (100) under 0.05M HCl are studied in situ at room temperature using Atomic Force Microscopy. The dissolution process of each crystal plane was followed by observed changes in topographic features. RESULTS: The results revealed that crystal plane (001) dissolves by receding step edges, and has a dissolution rate of 0.45 nm s(-1). Conversely. plane (100) displays crystal terrace sinking at an average rate of 2.93 nm s(-1). Calculated intrinsic dissolution values (g s(-1) cm(-2)) for planes (001) and (100) are 1.37 x 10(-7) gs(-1) cm(-2) and 8.36 x 10(-7) gs(-1) cm(-2), respectively. CONCLUSIONS: These values indicate that the rate of flux of material from plane (100) is approximately six times greater than that from plane (001), under 0.05M HCl. Interpretation of the data, based upon intrinsic dissolution rates and dissolution rate velocities, correlate with reported variations in the dissolution behavior of commercial aspirin products. These observations illustrate the suitability of the technique for characterizing the dissolution behavior of crystalline drugs.

Aspirin↗

Surface characterization of aspirin crystal planes by dynamic chemical force microscopy.

Tapping mode (TM) atomic force microscopy (AFM) has been applied in a novel fashion to characterize and distinguish the (001) and (100) surfaces of individual aspirin crystals. The surface characterization was achieved by amplitude-phase, distance (a-p,d) measurements employing gold-coated AFM probes functionalized with self-assembled monolayers (SAM). Experiments using model probes coated with -CH3 and -COOH terminated SAMs have been performed on the two aspirin crystal planes (001) and (100). Results indicate that the hydrophobic -CH3 terminated AFM probes had a greater degree of interaction with the crystal plane (001), whereas the -COOH terminated AFM probes had a larger interaction with the crystal plane (100). Interpretation of these data, based upon the chemistries of the probes, correlates with current understanding of the crystal surface chemistry derived from X-ray diffraction data and dissolution rate studies.

Anti-Inflammatory Agents, Non-Steroidal↗

Discrimination of polymorphic forms of a drug product by localized thermal analysis.

In chemical processing, it is important to distinguish between and identify polymorphic forms. We demonstrate the novel use of scanning thermal microscopy (SThM) and localized thermal analysis to distinguish and identify polymorphic forms of the drug cimetidine. These forms cannot be resolved by classical bulk thermal analysis. SThM reveals a sample consisting of a 50 : 50 mixture of the polymorphs contains regions of different thermal conductivity, corresponding to the different polymorphs. Localized thermal analysis of small volumes of pure polymorphic samples (approximately 50 microm3) shows that the origin of the thermal conductivity contrast lies, at least in part, with the presence of a surface water layer on the more hydrophilic polymorph.

Chemistry, Pharmaceutical↗

Extracranial giant cell arteritis.

Although giant cell arteritis (GCA) of the extracranial arteries is said to be relatively frequent, clinical manifestations are rarely recognized. We describe a case presenting with intestinal perforation who subsequently died with active GCA of the coronary, mesenteric and temporal vessels.

Aged↗

Giant cell reparative granuloma of the cricoid cartilage.

Giant cell reparative granuloma (GCRG) is an uncommon benign lesion which has been reported at several sites in the head and neck. We present a case of a GCRG of the cricoid cartilage not previously described in the literature. It must be differentiated from the brown tumour of hyperparathyroidism and true giant cell tumours of bone. These were excluded on clinical, biochemical, radiological and histological grounds. The lesion responded well to surgical debulking and curettage and the patient remained disease-free 15 months after treatment.

Cricoid Cartilage↗

Pathologist variation in reporting cervical borderline epithelial abnormalities and cervical intraepithelial neoplasia.

AIMS: To evaluate the interobserver variation in the diagnosis of cervical intraepithelial lesions, including the new category "borderline abnormalities of uncertain significance" (BAUS) which has not been tested before. METHODS: Biopsy specimens of 122 patients were reviewed by five histopathologists and the diagnoses subjected to kappa statistical analysis. RESULTS: There was poor interobserver agreement in all categories, particularly between BAUS and normal tissue. CONCLUSIONS: The current guidelines for the histological diagnosis of cervical intraepithelial neoplasia and BAUS are poorly reproducible.

Biopsy↗

A scanning tunnelling microscopy comparison of passive antibody adsorption and biotinylated antibody linkage to streptavidin on microtiter wells.

An antiferritin antibody was either, (a) passively adsorbed to microwells or (b) biotinylated and immobilised to streptavidin coated microwells. Scanning tunnelling microscope (STM) imaging of these well surfaces coated with a platinum (95%) carbon (5%) coating (Pt/C) conductive layer showed a randomly oriented array of antibodies for passive adsorption whereas for biotin-streptavidin immobilisation there was a more uniform and even distribution of antibodies on the well surface. On further incubation with ferritin STM imaging showed that for passive adsorption approximately 5% of the surface was functional, while for the biotinylated antibody it was greater than 60%. The images presented in this paper show graphically the loss of functionality that occurs using passive adsorption and, conversely, the preservation of antibody functionality using the biotin-streptavidin linkage for antibody immobilisation. These results correlate well with the work of others in the field.

Adsorption↗

True malignant mixed tumour of a minor salivary gland.

True malignant mixed tumours (carcinosarcomas) of salivary gland origin are rare and not widely recognized lesions. These tumours account for approximately 0.2 per cent of all malignancies of the major salivary glands (Stephen et al., 1986). They usually occur in pre-existing pleomorphic adenomas of major salivary glands and have an aggressive and often rapidly fatal progression. We report a case of carcinosarcoma in a minor salivary gland of the upper lip. Its management and the use of immunocytochemical stains to demonstrate the separate epithelial and connective issue components are discussed.

Adult↗

Surgical pathology of the liver in HIV infection.

In the 6-year period 1984-1989, 101 liver biopsies or 'needle necropsies' from human immunodeficiency virus positive patients were examined histologically. Of these, only nine showed no abnormality whatsoever. The commonest histological findings were either fatty change or changes related to co-existent chronic viral hepatitis. Granulomas were seen in 15 cases, four of which were positive for acid-fast bacilli. A range of organisms were recorded: cytomegalovirus (4); Histoplasma capsulatum (1); Pneumocystis carinii (2); Cryptococcus neoformans (1); and Leishmania donovani (1). There were two cases of non-Hodgkin's lymphoma, but no cases of Kaposi's sarcoma. Marked iron deposition, which correlated with multiple blood transfusions was seen in nine biopsies. We were unable to identify any histological feature in the liver as being specific for HIV infection. The high incidence of liver abnormalities reflects: (i) the coincident exposure to hepatotropic viruses; (ii) the presence of opportunistic infections and neoplasms, usually part of a disseminated multi-organ process arising in the setting of profound immune depression; (iii) iatrogenic causes, in particular iron overload related to multiple blood transfusions received for treatment of zidovudine-induced anaemia; and (iv) non-specific changes associated with chronic debilitating disease.

Acquired Immunodeficiency Syndrome↗