Biomedical subjects

D J Jeffries

Publications and source records attributed to D J Jeffries.

At least 37 records · Page 2Linked to original sources

PubMed1995

Viral hazards to and from health care workers.

Much attention has been directed towards nosocomial transmission of viruses as a result of clear evidence of patient-to-staff and staff-to-patient transmission of the blood-borne viruses HIV and hepatitis B virus. Although the relatively long incubation periods of these viruses, together with the frequency of asymptomatic infections, renders problems for surveillance it has been possible to study modes of transmission and levels of risk over a number of years. Information on trends of incidence of other nosocomial virus infections has been difficult to obtain for a number of reasons. Often, an outbreak in the health care setting parallels an epidemic in the community. Although it may be possible to define nosocomial transmission from recording dates of onset of illness relative to admission date and, at times, demonstrate circulation of a common strain by molecular techniques, the relative contributions of patient-to-staff and staff-to-patient transmission may be difficult to clarify. In this review, details are presented of the major viruses associated with nosocomial transmission with examples of infections to and from staff where these have occurred. The major defences against patient-to-staff and staff-to-patient transmission are awareness of potential risks, education and adherence to infection control policies, immunization of staff, effective decontamination and sterilization and the adoption of 'Universal Precautions' in patient care. In addition, there may be occasions when additional measures should be considered including isolation, cohorting and the use of specific chemo- and immunoprophylaxis.

Blood-Borne Pathogens↗

PubMed1995

Risk factors for HIV infection overlooked in routine antenatal care.

We have ascertained the extent to which risk factors for HIV infection may escape detection by standard history-taking procedures in an antenatal clinic. This study was based on 1264 women from a multi-ethnic population in an inner London health district (City and Hackney). All had agreed to undergo attributable HIV testing and a detailed personal interview. Thirty-nine per cent (494 of 1264 women) reported risk factors contributed personally or by a partner. Most of these risk factors had not been earlier disclosed by routine history taking. In most cases the risk was residence and risk activity in a World Health Organization (WHO) Pattern 2 country. [HIV spread WHO categories: Pattern 1--principally homosexual/bisexual males and i.v. drug use (areas = North America, Western Europe, Australasia, parts of South America) with male to female ratio 10/1; Pattern 2--Heterosexual (areas = Sub Saharan Africa, Caribbean and part South America) with male to female 1/1.] Thirty-one subjects (2.4%) were aware that their partners had participated in bisexual activity. Only six subjects perceived themselves at risk through their own or partner's drug injecting activity. The frequency of risk factors was substantially greater than that ascertained by the routine history. The findings highlight the potential risk of heterosexual spread resulting from travel to or residence in high prevalence territories. The contribution by male partners is significant and is particularly difficult to detect during a routine interview. These data support the recommendation that voluntary HIV serum testing should be universal rather than a selective offer based on risk factors determined at a routine history.

Female↗

PubMed1994

Enteroviruses, endoscopy and infection control: an applied study.

Decontamination methods for medical equipment are based largely on bacterial studies yet enteroviruses are more resistant to disinfection than most vegetative bacteria and other viruses. To study the elimination of enteroviruses from endoscopes, poliovirus was aspirated into the suction-biopsy channels of five gastroscopes. Endoscopes were cleaned in detergent and disinfected in 2% alkaline glutaraldehyde. Contamination was measured before and after cleaning and after various periods of disinfection by irrigating the channels with viral medium and quantifying surviving virus by plaque assay. The effectiveness of glutaraldehyde against cell-free and cell-associated polio virus, dried to a surface in a protein coagulum, was also studied. Cleaning reduced virus by a mean of 4.6 log10 plaque forming units (pfu) ml-1. Samples were virus-free after 2 min disinfection. Virus dried on surfaces was inactivated in 1 min by 2% and 1% glutaraldehyde, with a reduction of > 6 log10 pfu ml-1. Thus, cleaning was effective against heavy viral contamination while glutaraldehyde rapidly inactivated poliovirus even when dried to a surface in serum.

Detergents↗

PubMed1994

Evaluation of an antenatal HIV testing programme in an inner London health district.

OBJECTIVE: To study an antenatal human immunodeficiency virus (HIV) testing programme in an inner London health district. DESIGN: A standardised research interview was given to women in the first half of pregnancy and the findings were compared with those of the routine clinical interview. The observations were analysed in relation to the results of HIV antibody testing, either attributable by consent or anonymously, in these women. SETTING: The Homerton Hospital, London. SUBJECTS: Three thousand seven hundred and twenty-nine women, of whom 1696 (45.5%) consented to testing. RESULTS: Four women who had consented to testing had a positive result. Amongst the 2,033 women (54.5%) who declined the test, four (or five) had a positive result. The number of risk factors ascertained by the research study interview was substantially greater than that elicited by the preceding routine interview. In addition, more information was obtained by a routine computer interview than by its unstructured equivalent. There was no obvious association between the presence of a risk factor and whether or not the women had consented to the test. CONCLUSIONS: Our formal voluntary testing programme detected nearly 44% of HIV seropositive individuals. Thus, there were four known positives during the study period against a total of nine detected by anonymous testing. Since all the known positive results in the study were associated with recognised risk factors, there is some doubt as to the value of a universal testing programme. However, if testing is to be based upon the existence of a risk factor elicited at the booking history, then the deficiencies in this history revealed by the present study need to be corrected.

Female↗

PubMed1993

Nucleoside analogues previously found to be inactive against HIV may be activated by simple chemical phosphorylation.

Nucleoside analogues previously found to be inactive against the human immunodeficiency virus (HIV) may be activated by simple chemical derivatisation. As part of our effort to deliver masked phosphates inside living cells we have discovered that certain phosphate triester derivatives of inactive nucleoside analogues become inhibitors of HIV replication. This discovery underlies the importance of the masked phosphate approach, and has significant implications for the future design of chemotherapeutic nucleoside analogues. If highly modified nucleoside analogues may be active without the intervention of nucleoside kinase enzymes, major advantage may accrue in terms of low toxicity and enhanced selectivity. Moreover, the increased structural freedom may have implications for dealing with the emergence of resistance. The concept herein described as 'kinase bypass' may thus stimulate the discovery of a new generation of antiviral agents.

Antiviral Agents↗

PubMed1993

DNA amplification by the polymerase chain reaction to detect sub-clinical Pneumocystis carinii colonization in HIV-positive and HIV-negative male homosexuals with and without respiratory symptoms.

Pneumocystis carinii colonization was studied in 90 men using the polymerase chain reaction. These comprised ten heterosexual controls; ten HIV-seronegative homosexual controls; 20 HIV-seropositive homosexuals with blood CD4 count > 400 x 10(6) l-1; 20 HIV-seropositive homosexuals with CD4 < 400 x 10(6) l-1; ten HIV-seropositive homosexuals with CD4 < 60 x 10(6) l-1 receiving PCP chemoprophylaxis; and 20 HIV-seropositive homosexuals with respiratory symptoms but without PCP. Induced sputum was obtained from all but the last group, who had bronchoalveolar lavage, and all specimens were tested for P. carinii using the polymerase chain reaction. The first four groups received no pneumocystis chemoprophylaxis, and all but the last group were asymptomatic. P. carinii colonization did not occur in the two control groups. P. carinii colonization rates were significantly different in the CD4 > 400, CD4 < 400, and CD4 < 60 groups (10%, 20%, and 40% respectively) (P < 0.025). Two patients (one each from CD4 < 400 and CD4 < 60) developed PCP 4-6 weeks after sputum induction, both had previously had high levels of P. carinii on sputum induction. Two patients from the CD4 < 400 group had high levels of P. carinii but did not develop PCP. In the symptomatic group, two subjects had low levels of P. carinii, but did not develop PCP. We have demonstrated P. carinii colonization in HIV-seropositive homosexuals in association with a low peripheral CD4 count. The polymerase chain reaction may be a useful technique for determining the need and efficacy of anti-pneumocystis chemoprophylaxis.

Adult↗

PubMed1992