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Biomedical subjects

R G Mathias

Publications and source records attributed to R G Mathias.

At least 19 recordsLinked to original sources
PubMed1995

Dentistry and tuberculosis in the 1900s.

The number of new cases--or incidence--of tuberculosis is increasing in nearly every region of the world. A number of forces have resulted in the increased incidence of TB in developed countries, including the HIV epidemic, homelessness, and emigration from highly endemic regions. Although the number of new cases in Canada is relatively constant, the TB experience in the United States serves as a reminder that this situation could change rapidly. The appearance of multidrug-resistant tuberculosis has added to the urgency of situation. The basic methods of preventing TB transmission include preventing the release of the organism into the air, removing the organism from the air, and preventing the inhalation of the organism. Identifying and appropriately treating every person with active tuberculosis is an extremely important component of the control strategy; adequate ventilation, filtering air, and ultraviolet germicidal irradiation are methods used to remove the organism from the air; and masks and other personal protective devices, such as high-efficiency particulate air filters (HEPA), have been suggested as a means of preventing inhalation of the organism. In addition, identifying new TB infections and using chemoprophylaxis often prevents infection from progressing to active disease. Given the route by which tuberculosis is transmitted, it is necessary for both dentists and allied dental personnel to be aware of the risks they may face in day-to-day practice, and the means by which they can protect themselves and their patients.

Air Microbiology↗
PubMed1995

Survey to assess dental practitioner's knowledge of infectious disease.

The prerequisite to understanding the need for infection control practices in dentistry is a sound knowledge of infectious disease and the potential for its transmission in the dental setting. To assess the infectious disease knowledge-base of dental practitioners, a questionnaire was developed and distributed to dentists in British Columbia. The survey results showed that many of the mechanisms, routes and risks for the transmission of viral pathogens in the dental setting are not clearly understood by dentists. Continuing education is needed to ensure that compliance with current infection control recommendations, and the provision of appropriate patient care, continues to be based on a clear understanding by dentists of the mechanisms of infection. By identifying the current infectious disease knowledge-base of dentists, this survey may permit more specifically-directed continuing education programs to be offered.

Adult↗
PubMed1995

Compliance to recommended infection control procedures: changes over six years among British Columbia dentists.

Over the last decade, in response to the heightened awareness of HBV and HIV infections, world health authorities have produced specific infection control recommendations for dental practices. Surveys have been done in various countries to investigate the level of compliance to these recommendations. This paper reports on the changes in compliance over a six year period among British Columbia dentists, as indicated from four volunteer surveys conducted between 1987 and 1993. During that period, the percentage of dentists who reported taking a medical history for each new patient increased from 70 per cent to 99 per cent. The routine use of gloves increased from 61 per cent to 95 per cent, and of face masks from 49 per cent to 83 per cent. In 1993, most dentists (91 per cent) used a new pair of gloves with each patient, up from 62 per cent three years earlier. Dentists also reported on their sterilization and hygiene methods. Autoclavable handpieces were used by 66 per cent of respondents in 1990, and by 74 per cent in 1993. High-speed autoclavable handpieces were used by 83 per cent of dentists in 1993, but only 62 per cent sterilized these handpieces. Similarly, 65 per cent reported using low-speed autoclavable handpieces, but only 47 per cent sterilized them. It is apparent that disinfection of handpieces and intraoral instruments is still an important part of regular operatory hygiene. Biologic monitors were used by 61.6 per cent of respondents to test the efficiency of their office sterilizer in 1993.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Survey of knowledge of infectious disease and infection control practices of dental specialists.

A questionnaire was developed to assess the knowledge of clinical specialists regarding infectious disease as well as their infection control practices. The questionnaire was mailed to 202 dental specialists in British Columbia. Seventy per cent returned completed surveys. Their responses indicate that the mechanisms, route and risk of transmission of the viral pathogens of importance in dental practice are not clearly understood. However, infection control practices closely follow the guidelines set forth by the Canadian Dental Association and the licensing bodies, including immunization for hepatitis B (82 per cent), glove use (in 89 per cent of non-surgical and 95 per cent of surgical procedures), and sterilization/disinfection of dental handpieces (94 per cent). Compliance with infection control guidelines was similar to that reported in the United States, where strict enforcement has been instituted. The majority of dental specialists (84-88 per cent) were either treating or willing to provide treatment to patients with infectious disease. Continuing education in the area of infectious disease is needed to improve dentists' understanding of the risk of transmission to dental providers and patients. This will ensure that compliance with infection control recommendations and appropriate patient care practices continue.

Analysis of Variance↗
PubMed1994

Long-term follow-up of hepatitis B vaccine in infants of carrier mothers.

A program of immunization against hepatitis B, consisting of one dose of hepatitis B immune globulin within 12 hours of birth and three doses of hepatitis B vaccine at 0, 1, and 6 months of age for all infants of carrier mothers, has been operating in British Columbia, Canada, since 1984. The authors report on a survey conducted in 1992 of children immunized between 1984 and 1989. The survey included blood tests obtained from the children and interviews of the mothers. A total of 770 of 1,135 eligible children participated. Thirty-one percent of the mothers had been positive for hepatitis B e antigen prior to the birth of the child. At follow-up, the overall antibody against hepatitis B surface antigen seropositivity rate for children was 87.9 percent. A total of 5.1 percent of children had evidence of previous hepatitis B infection, and 2.3 percent were hepatitis B surface antigen positive. In multiple logistic regression analysis, a delay in the initial dose of vaccine was associated with increased risk of infection, but the age of the child was not, even though antibodies against hepatitis B surface antigen declined with age. The authors conclude that most infections occurred early and resulted from prenatal infection, initial nonresponse, or a delay in the initial dose of vaccine, not from waning immunity. A booster dose of vaccine, at least up to age 8 years, is not necessary.

Analysis of Variance↗
PubMed1994

Prevalence of HIV infection in provincial prisons in British Columbia.

OBJECTIVE: To ascertain the prevalence of HIV infection among people entering provincial adult prisons in British Columbia and to study associations between HIV infection and specific demographic and behavioural characteristics. DESIGN: Prospective, unlinked, voluntary survey involving HIV antibody testing of saliva specimens. SETTING: All adult provincial prisons in British Columbia through which inmates are admitted to the provincial correctional system. PARTICIPANTS: All adult inmates admitted to provincial prisons in British Columbia between Oct. 1 and Dec. 31, 1992. OUTCOME MEASURES: Rate of HIV positivity. Independent variables included sex, native status (native or non-native), self-reported HIV status, age group and history of injection drug use. RESULTS: A total of 2482 (91.3%) of 2719 eligible inmates volunteered for testing. Refusal was not associated with sex, native status, self-reported HIV status or age group; inmates who reported a history of injection drug use were more likely than the others to refuse HIV antibody testing (12.9% v. 6.8%; p < 0.001). The 2482 inmates who were tested for HIV were similar to the general inmate population with regard to sex, native status and age group. A total of 28 inmates were confirmed to be HIV positive, for an overall prevalence rate in the study population of 1.1% (95% confidence interval 0.8% to 1.6%). The prevalence rates were higher among the women than among the men (3.3% v. 1.0%; p = 0.023, Fisher's exact test) and among the inmates who reported a history of injection drug use than among those who did not report such a history (2.4% v. 0.6%; p < 0.001). There was no association between HIV status and native status or age group. Logistic regression analysis revealed the higher prevalence rate among the women to be explained by more of the women than of the men reporting a history of injection drug use. Of the 30 people who stated that they were HIV positive and who were tested, 19 (63.3%) had a negative result; conversely, 17 who reported that they were HIV negative or had not been tested had a positive result. CONCLUSIONS: Unlinked, voluntary HIV antibody testing of inmates can achieve high participation rates. The overall prevalence rate of 1.1% and the rate among the female inmates of 3.3% confirm that HIV infection is a reality in prisons and that the virus has established a clear foothold in inmate populations. Harm-reduction interventions should include a comprehensive education program for inmates on infectious diseases, the availability of condoms throughout prisons and the distribution of bleach for sterilizing needles and syringes. From a public health perspective, these data suggest an urgent need for access to sterile injection equipment in addition to other preventive measures.

AIDS Serodiagnosis↗
PubMed1992

Management of Chlamydia trachomatis genital infections: reported practices of primary care physicians.

OBJECTIVE: To determine the knowledge of primary care physicians about Chlamydia trachomatis genital infection and its management. DESIGN: Self-administered questionnaire comprising direct questions and hypothetical cases. PARTICIPANTS: All 108 general and family practitioners on the north shore of Vancouver were sent the questionnaire; 79 (73%) responded. RESULTS: There was a reasonable level of knowledge in many areas, particularly among the physicians who had graduated more recently than the others. Virtually all stated that they have access to chlamydial diagnostic testing, and most indicated that they test for chlamydial infection at least occasionally. However, many of the respondents failed to consider that youths in their practice may be sexually active, and only 28% knew that women 15 to 19 years of age have the highest reported rates of chlamydial infection. Many of the physicians were confused about syndromes that are or are not associated with C. trachomatis infection; this indicated the possibility of inappropriate testing and treatment decisions. If they had to test for C. trachomatis in a prepubescent girl 34% reported that they would obtain a specimen from the endocervix, a technique that is inappropriately invasive. When presented with a positive test result many of the respondents failed to consider the possibility of a false-positive result. Fortunately all of the physicians were well informed about correct treatment regimens for C. trachomatis infection, although many did not realize how effective they really are. In the case of a young man with suspected or proven gonorrhea or a young female outpatient with pelvic inflammatory disease, only 19% and 20% respectively stated that they would prescribe a regimen appropriate for both penicillinase-producing Neisseria gonorrhoeae and C. trachomatis. Many of the respondents had not heard of management guidelines, and fewer still reported that they consult them. CONCLUSIONS: Despite the availability of several sets of guidelines there appear to be important gaps in the knowledge and practice of many primary care physicians with respect to genital infections. Since the preparation of guidelines is time-consuming and expensive, further work should be done to evaluate their impact and to address their limitations.

Adolescent↗
PubMed1991

The efficacy of treatment with albendazole.

Albendazole, a benzimidazole derivative, was administered as a single dose of either 400 mg or 600 mg to two groups to ascertain the efficacy, tolerance and safety of the regimens. At a dose of 400 mg, a cure rate 35/36 (97%) against Ascaris was found. At 600 mg, the cure rate was 21/30 (70%), significantly lower than the 400 mg rate. Against Trichuris, albendazole at 400 mg had a cure rate of 21/48 (44%), at 600 mg there was a cure rate of 29/43 (67%). Mild side effects were noted in 7 individuals. Whether the moderate increase in efficacy against Trichuris and the loss of efficacy against Ascaris improves the cost:benefit ratio must be left to the prescriber of the drug.

Adolescent↗
PubMed1991

Hepatitis & HIV: prevalence of infection and changing attitudes toward infection control procedures in British Columbia.

Dental professionals attending the annual meeting of the College of Dental Surgeons of British Columbia in June 1990 were involved in a survey to assess the prevalence of infection with Hepatitis B, Hepatitis C and Human Immunodeficiency viruses, the acceptance of vaccination for protection against Hepatitis B virus, and the compliance with infection control guidelines. Participation was voluntary and anonymous and required completion of a questionnaire and donation of a blood sample. Four hundred one of 1,995 convention attendees participated. Fourteen were found to have markers of Hepatitis B infection; 13 had antibodies to both Hepatitis B surface antigen and Hepatitis B core antigen, and one was positive for Hepatitis B surface antigen. One individual had markers for both Hepatitis C and Hepatitis B viruses. None tested positive for antibody to Human Immunodeficiency virus. Vaccination against Hepatitis B virus was reported overall by 67 percent of the participants, but dentists and hygienists had a higher rate of vaccination (82 percent and 81 percent, respectively) when compared to dental assistants (41 percent; P less than .001). Acceptance of infection control procedures was high, with 92 percent of participants reporting use of gloves for all patients and 82 percent reporting use of masks and eye protection.

Attitude of Health Personnel↗
PubMed1991

Hepatitis B and HIV infections in dental professionals: effectiveness of infection control procedures.

In a survey carried out in 1987 and 1988 in Vancouver British Columbia, 704 dental professionals filled out an anonymous questionnaire and submitted a blood sample. Of those not immunized, 11% had infection with Hepatitis B, with dentists having a rate of 18%, significantly higher than other dental workers. Two carriers of HBsAg were detected and no individuals showed evidence of HIV infection. There were no differences in infection rates by the specific infection control practices. Oriental dental-care workers had a significantly higher rate of infection than other races surveyed. In a multivariate model, race and the number of years in practice were the only significant factors in predicting infection. The use of gloves did not show a protective effect, although a threefold protection rate for gloves is the smallest difference that could be reliably detected. The immunization rate with Hepatitis B vaccine averaged 46%, with fewer dentists being immunized than hygienists. Seroconversion rates were lower in older individuals. Dental professionals had a high risk of Hepatitis B and had not been adequately immunized. Reliance on gloves for operator protection appears to be inadequate.

Adult↗
PubMed1990

Antibodies to Plasmodium falciparum in an indigenous population from a malaria endemic area of Malaysia.

Indirect fluorescent antibody (IFA) tests and enzyme-linked immunosorbent assays (ELISA) were used to measure antibodies to Plasmodium falciparum in an indigenous population in an area of Malaysia with high malaria prevalence. The results of three surveys were analyzed to examine the relation of these serologic measures with age, parasite rate, and spleen size. For children 0-4 years old, increasing spleen size was associated with an increasing likelihood of malaria parasitemia, while for 5-9 year olds the two variables were unrelated. Parasite rate declined with age and ELISA titre increased with age in all surveys; IFA titre was consistently high and did not vary with age. Neither antibody measure was significantly correlated with either the presence or the actual density of parasitemia. These antibody measures are most useful as adjuncts to the more traditional techniques of malaria assessment.

Adolescent↗
PubMed1990

Adoption of guidelines for Universal Precautions and Body Substance Isolation in Canadian acute-care hospitals.

The impact of recently recommended hospital infection control guidelines on Canadian acute-care hospitals is unknown. A confidential cross-sectional mailed survey of all acute-care Canadian hospitals was conducted to determine rates of receipt and adoption of published guidelines for Universal Precautions (UP) or Body Substance Isolation (BSI), rationale for adoption and knowledge of costs and benefits. Five hundred and seventy-nine of 943 sites (61%) responded (exceeding 80% in urban centers); 94% among hospitals with at least 300 beds and 57% among those under 300 beds. Seventy-four percent of responders claimed adoption of UP (65%) or BSI (9%), staff protection being their primary motivation. Adoption of either UP or BSI was associated with size (p less than .001), increasing progressively from 45% in the smallest group (less than 25 beds) to 84% in the largest (greater than or equal to 500 beds). Many hospitals introduced modifications and some substituted names other than UP or BSI in adopting a new strategy. In practice, UP and BSI now mean different things in different hospitals, and the distinction between them has become blurred. Furthermore, only 5% claiming adoption of a new strategy adopted all of the fundamental policies expected under UP or BSI. Receipt of guidelines was also correlated with size: one-third of hospitals under 200 beds had not received key publications defining UP and BSI. Only 19% claiming adoption of a new strategy indicated knowledge of cost implications. These results suggest a need for closer collaboration among hospitals and government agencies in developing uniform infection control policies, and for systematic evaluation of the cost and effectiveness of new strategies.

Body Fluids↗
PubMed1990

Epidemiology and pathogenicity of Blastocystis hominis.

A prospective study was performed on a large outpatient population to evaluate the epidemiology and pathogenicity of Blastocystis hominis. Patients with stool specimens positive for B. hominis and negative for other bacterial and parasitic pathogens were sent a questionnaire and were requested to submit a follow-up specimen for ova-and-parasite examination. B. hominis was identified in 530 of 16,545 specimens (3.2%). There was a spectrum of clinical-pathological presentations in the 143 patients evaluated. An asymptomatic carrier state was seen in 19 patients. Fifteen patients had an illness consistent with acute self-limited B. hominis gastroenteritis, and 21 patients had chronic gastroenteritis associated with B. hominis. In the epidemiological evaluation of 130 patients, the most common symptoms were watery diarrhea, abdominal pain, and gas. We did not find a statistically significant association between the number of organisms present and the disease state. In summary, our results are consistent with a role for B. hominis in acute and chronic gastroenteritis; however, further detailed studies are necessary to determine whether that role is one of association or causation.

Adolescent↗