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Biomedical subjects

N Williamson

Publications and source records attributed to N Williamson.

At least 19 recordsLinked to original sources
PubMed2001

Unexplained deaths among injection drug users: a case of probable Clostridium myonecrosis.

A series of unexplained deaths associated with soft-tissue inflammation and severe systemic sepsis was reported among injection drug users (IDUs) in the United Kingdom and the Republic of Ireland in 2000. Health Canada has identified one reported fatality in an IDU that matched the case definition. Although the cause of the epidemic in the UK and Ireland is not fully understood, contributing factors include injecting into muscle or beneath the skin, rather than directly into a vein, and the use of acid to dissolve the heroin. This single Canadian case is considered to be a sporadic event that occurs at a low background rate among IDUs. These cases serve to remind primary health care providers to be vigilant in cases of soft-tissue infection among IDUs and not to underestimate the potential severity of the situation.

British Columbia↗
PubMed2001

Reduction of chronic aggressive behaviour 10 years after brain injury.

This study demonstrates the successful management of aggressive behaviour with a client 10 years post-injury in a small, residential neurorehabilitation unit. The case presented is unusual for two main reasons. First, it proved possible to significantly modify previously chronic challenging behaviour many years after brain injury had been sustained. Secondly, the rehabilitation environment in which treatment was conducted did not comprise a highly specialized neurobehavioural service, Instead, staff were specifically trained regarding the administration of the treatment programme, which was based on principles derived from behaviour modification and applied neuropsychology. Specific interventions used included those of differential reinforcement and graduated increase of expectations. Recordings made over the course of 85 weeks demonstrate a significant decrease in the frequency and severity of aggression. Successful inhibition of challenging behaviour attained a level which facilitated transfer of the client to a non-institutionalized community home. Reasons underlying the success of the intervention, and the limitations inherent in attempting to manage aggression within neurorehabilitation environments will be discussed.

Adult↗
PubMed2000

Molecular detection of bacterial and streptomycete chitinases in the environment.

Sets of PCR primers were designed to amplify bacterial chitinases at different levels of specificity. The bacterial chitinase group primers were successful in targeting enzymes classified within the group A glycosyl hydrolases of family 18. The widespread occurrence of group A bacterial chitinases in actinomycetes was demonstrated. Streptomycete chitinase specific primers were designed and a collection of type strains of species changed in the genes Streptomyces were screened and shown to have at least one and usually multiple chitinase genes. The presence of the gene for the chitin binding protein was also demonstrated within the streptomycete type strains. These data indicate that streptomycetes are well equipped to degrade chitin. The detection of group A chitinases in total community DNA is described and a sandy soil shown to contain more than 10 different genes using DGGE to indicate genetic diversity.

Actinomycetales↗
PubMed1994

The effect of husband counseling on NORPLANT contraceptive acceptability in Bangladesh.

A pilot study of the effect of husband counseling on NORPLANT contraceptive acceptability was conducted at four family planning clinics in Bangladesh. The study objectives were to compare discontinuation rates and user satisfaction among acceptors whose husbands received counseling about the method versus those who did not. Of a total 617 subjects enrolled in the study which began in 1988, about two-thirds (408) of the husbands were counseled at admission or at the one-month follow-up visit while the remainder of the husbands (209) were not counseled. Follow-up visits were scheduled at one and six months after NORPLANT implants insertion, and every six months thereafter until the close of the study in 1991. Some evidence was found that counseling husbands of NORPLANT implants acceptors may reduce discontinuation rates. At the end of 36 months, a difference of 10 percentage points in total discontinuation rates was observed between the husband-counseled group (32 per 100 women) and the husband-not-counseled group (42 per 100 women). The husband counseling had the most impact at clinics with higher discontinuation rates. Based on Cox's proportional hazards regression model results, the hazard for discontinuation among the acceptors in the husband-not-counseled group. Satisfaction with NORPLANT implants did not differ between the two groups. Although these results are not striking, they do suggest a potential positive effect of husband counseling on NORPLANT contraceptive accept-ability. In future studies, the counseling of husbands should be more intensive and standardized.

Adolescent↗
PubMed1993

Identification, counselling, and outcome of two cases of prenatally diagnosed supernumerary small ring chromosomes.

De novo supernumerary small ring chromosomes have mainly been reported in pediatric patients with clinical abnormalities, thus, there may be bias of ascertainment. Reports on prenatally diagnosed cases with postnatal follow-up are rare. With the availability of chromosome specific alpha-satellite centromeric probes, the interest in these previously unidentifiable supernumerary small ring chromosomes has been rekindled [Callen et al.: J Med Genet 27: 155-159, 1990; Callen et al.: Am J Hum Genet 48:769-782, 1991; Callen et al.: Am J Med Genet 43:709-715, 1992]. We report on 2 prenatal diagnosis cases, where a ring was noted in 25 and 60% of the amniocytes, respectively. The initial G- and C-banding in Case 1 allowed an assumption of a chromosome 1 origin of the extra chromosome. This was confirmed by fluorescence in situ hybridization (FISH) studies using the appropriate probes. No similar initial assumption could be made in Case 2; thus, random trials with multiple probes were performed. A chromosome 19 origin in Case 2 was eventually concluded. The large amount of C-band positive material on the extra chromosome and the normal level 2 fetal ultrasound examination suggested a favorable outcome in both cases, but the possibility of mental retardation could not be ruled out. An empiric risk figure with regard to prenatally diagnosed de novo supernumerary small ring chromosomes is not available. Although the decision making processes of the parents were different, they both decided to continue the pregnancy. At age 9 months and 1 1/2 years both children, a girl and a boy, showed normal growth and development.

Adult↗
PubMed1989

A pseudoisochromosome 18q and an isodicentric chromosome 18.

A case of pseudoisochromosome 18q of prezygotic origin and a case of isodicentric chromosome 18 of postzygotic origin are presented to validate the differentiation between a true isochromosome and a pseudoisochromosome. This differentiation may be useful in elucidating the mechanism of the origin of an isochromosome.

Abnormalities, Multiple↗
PubMed1986

Epidemiologic study of Holstein dairy cow performance and reproduction near a high-voltage direct-current powerline.

The development and operation of a high-voltage direct-current (HVDC) transmission line in rural Minnesota generated public concern over potential adverse effects to nearby residents and their livestock. Electrical environmental parameters near an HVDC line decline rapidly with distance, but effects on ambient space charge have been detected out to 1 mile. Previous studies of powerline effects on livestock have involved the more common alternating-current (HVAC) lines, which create a different electrical environment. To identify potential adverse effects of HVDC line operation on livestock, case-control and cohort study methods were used to examine various indices of Holstein performance in relation to distance from the line and the onset of line operation. It was believed that these indices would reflect changes in physiologic function or overt health effects that might arise from the HVDC environment. High-quality performance data from existing Dairy Herd Improvement Association (DHIA) records were obtained for 97% of qualifying herds located within 10 miles of the line. The large number of animals and years of observation provided high statistical power to detect even small systematic changes in performance. No significant differences in milk production or reproductive capacity were associated with presumed exposure to the HVDC environment. The absence of measurable effects in a large "sentinel" animal population may have implications for the assessment of human health risks related to HVDC transmission lines.

Abortion, Veterinary↗