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Biomedical subjects

K E Nelson

Publications and source records attributed to K E Nelson.

At least 181 records · Page 10Linked to original sources
PubMed1991

HIV seroconversion and disinfection of injection equipment among intravenous drug users, Baltimore, Maryland.

To examine the putative protective effect of disinfectant use on HIV seroconversion among intravenous drug users, we conducted a nested case-control study comparing 22 black heterosexual HIV seroconverters with 95 persistent seronegatives matched on gender, use of cocaine, date of study entry, and duration of follow-up. For intravenous drug users who reported using disinfectant all the time, the odds of seroconversion was 0.77 (95% CI: 0.25-2.38) compared with those who reported no use of disinfectants; for those who used disinfectants some of the time, the corresponding odds ratio was 0.91 (95% CI: 0.26-3.31). The odds ratio for use of disinfectant all the time was 0.63 (95% CI: 0.10-3.91) for those injecting at galleries and 1.08 (95% CI: 0.35-3.11) for those not injecting at galleries. These data suggest a limited protective effect of disinfectant use in the field which may be more beneficial to those injecting in shooting galleries.

Adult↗
PubMed1991

Risk factors for shooting gallery use and cessation among intravenous drug users.

BACKGROUND: Shooting galleries, locations where intravenous drug users (IVDUs) can rent or borrow needles and syringes, are a high-risk environment for HIV-1 transmission. This study investigates risk factors for lifetime attendance at shooting galleries and differentiates characteristics of those who continue to frequent shooting galleries and those who have stopped. METHODS: We interviewed 2615 active IVDUs in Baltimore in 1988 and 1989 and determined patterns of IV drug use, sociodemographics, and HIV-1 serostatus as related to persistence vs cessation of shooting gallery use. RESULTS: Over half (52%) of active IVDUs reported ever using a shooting gallery, with 33% reporting use within the prior 3 months. In multivariate analysis, lifetime shooting gallery use was associated with male gender, homosexuality/bisexuality, low socioeconomic status, Black race, and heavier drug involvement. Persistent shooting gallery users were more frequently male, homosexual/bisexual, homeless, less educated, and started IV drug use more recently compared with those who ceased going to shooting galleries. CONCLUSIONS: Shooting gallery attendance may be pragmatic from a sociological and economic perspective, but it carries with it a heightened risk of acquiring HIV-1 infection.

Adult↗
PubMed1991

Effect of glucocorticoids and interferon-gamma on the oxidative responses of monocytes from leprosy patients and normal donors.

Leprosy patients suffering from erythema nodosum leprosum are frequently treated with glucocorticosteroids. The role glucocorticosteroids and interferon-gamma (IFN-gamma) play in regulating the interaction of phagocytic cells with Mycobacterium leprae was examined. Monocytes from leprosy patients receiving prednisone therapy responded to lower concentrations of IFN-gamma in vitro with enhanced superoxide anion release when challenged with M. leprae or M. bovis BCG than did monocytes from healthy subjects and other leprosy patients. Although the number of patients was small and the population heterogeneous, the data suggested that prednisone could alter IFN-gamma efficacy and led to the examination of the effect of glucocorticosteroids on IFN-gamma activation of monocytes. IFN-gamma treatment following in vitro dexamethasone pretreatment of monocytes from healthy subjects resulted in a greater enhancement of superoxide anion generation than that observed with IFN-gamma treatment alone. These findings are important considerations in evaluating patient immune function because IFN-gamma is being used in a number of clinical trials with leprosy patients.

Adult↗
PubMed1991

Effect of BCG on the risk of leprosy in an endemic area: a case control study.

The effect of BCG on the risk of leprosy was measured using a case-control design in an area endemic for the disease. In this study, 397 newly diagnosed cases and 669 controls matched for age, sex and locality were selected from a defined population. Information on exposure to BCG, contact with another case of leprosy, and relevant socioeconomic variables were obtained from the subjects. Having infectious (multibacillary) and noninfectious (paucibacillary) contacts in the household increased the risk of disease 11.7 times (p less than 0.001) and 2.7 times (p less than 0.001), respectively. Overall, the protection offered by BCG was not significant (odds ratio = 0.8; p = 0.17). However, BCG appeared to increase the risk for indeterminate leprosy (adjusted odds ratio = 2.7; p = 0.09) while protecting against borderline disease (adjusted odds ratio = 0.39; p = 0.03). It is possible that BCG causes a shift in the overall cell-mediated immune response, thus increasing the risk for milder and transient forms of leprosy while protecting against more serious forms. These findings may have important implications for the design and interpretation of vaccine trials. Namely, trials should be designed to measure the protective efficacy of vaccines against the more serious forms of leprosy, which have the greatest public health significance.

Adolescent↗
PubMed1990

Blood and plasma donations among a cohort of intravenous drug users.

We evaluated the blood and plasma donation histories of a cohort of 2921 intravenous drug users in Baltimore, Md, and correlated these histories with their human immunodeficiency virus (HIV) serologic status, numbers of CD4 lymphocytes in the peripheral blood, and stigmata of intravenous drug use (scarred veins). Of the 793 intravenous drug users (27.1%) who had donated blood or plasma, 652 (82.2%) donated after they had started using intravenous drugs. Most subjects donated at commercial plasma centers, where they were paid $10 to $15 per donation. Although the HIV-1 seroprevalence of the entire cohort was 24.1%, the HIV-1 seroprevalence among those reporting plasma or blood donations declined progressively with time, from 17.1% in those who last donated in 1985 to 3.6% in those who last donated in 1988-1989. Many of the 437 intravenous drug users who had donated plasma or blood since 1985, when screening for HIV-1 was initiated, had not been notified and counseled about their HIV test results. Current programs to exclude individuals with a history of intravenous drug use from the plasma donor pool should be reevaluated and improved.

Baltimore↗
PubMed1990

Intra- and extraluminal sarcoplasmic reticulum membrane regulatory sites for Ca2(+)-induced Ca2+ release.

A heavy skeletal muscle sarcoplasmic reticulum (SR) fraction was actively loaded stepwise with calcium until Ca2(+)-induced Ca2+ release occurred. The total Ca2+ load, T1, at which release occurred is postulated to be regulated by an intraluminal, low-affinity receptor. After obtaining T1, the critical concentration of Ca2+ required extraluminally (T2) was determined. T1 averaged 58.6 +/- S.D., 6.9 nmol Ca2+/mg SR and T2 averaged 2.14 +/- S.D., 0.24 microM. Both T1 and T2 were increased by Mg2+ and decreased by caffeine. Ruthenium red increased T2 more than T1 while ryanodine had no effect on T1 but markedly increased T2. The results suggest that two Ca2+ regulatory sites may be functional for Ca2(+)-induced Ca2+ release from SR.

Analysis of Variance↗
PubMed1990

Inferences about guessing and knowing by chimpanzees (Pan troglodytes).

The visual perspective-taking ability of 4 chimpanzees (Pan troglodytes) was investigated. The subjects chose between information about the location of hidden food provided by 2 experimenters who randomly alternated between two roles (the guesser and the knower). The knower baited 1 of 4 obscured cups so that the subjects could watch the process but could not see which of the cups contained the reward. The guesser waited outside the room until the food was hidden. Finally, the knower pointed to the correct cup while the guesser pointed to an incorrect one. The chimpanzees quickly learned to respond to the knower. They also showed transfer to a novel variation of the task, in which the guesser remained inside the room and covered his head while the knower stood next to him and watched a third experimenter bait the cups. The results are consistent with the hypothesis that chimpanzees are capable of modeling the visual perspectives of others.

Animals↗
PubMed1990

Association of drug injection patterns with antibody to human immunodeficiency virus type 1 among intravenous drug users in Baltimore, Maryland.

During 1988 and 1989, intravenous drug users recruited through extensive community outreach efforts in Baltimore, Maryland, were interviewed about drug injection and sex practices in the prior 11 years, with screening for antibody to human immunodeficiency virus type 1 (HIV-1). Neither interviewers nor subjects were aware of HIV-1 serostatus until 2 weeks after the interview. Among 2,616 intravenous drug users who last injected drug within the same calendar year as screening, HIV-1 seroprevalence was 30.1% for those with any use of shooting galleries, 23.3% for those who shared needles but did not use shooting galleries, and 16.3% for drug users who denied both needle-sharing and gallery use between 1977 and 1987. Among 608 drug users who reported persistent use of shooting galleries since 1977 or subsequent initiation into drug use, there was a tendency for HIV-1 seroprevalence to increase with more recent onset of an injection career. Combined with a milder but similar tendency among 739 drug users who reported persistent sharing of needles, and a seroprevalence of 15.1% among participants who had just started injecting drugs in the 18 months prior to baseline, these data provide indirect evidence that a high risk for HIV-1 infection might occur early during a drug injection career.

Acquired Immunodeficiency Syndrome↗
PubMed1990

The risk of transmission of HIV-1 through non-percutaneous, non-sexual modes--a review.

To date, three well-documented modes of transmission of HIV-1 (sexual, percutaneous and perinatal) have been described. Although the theoretical possibility exists for HIV-1 transmission through other routes, including non-percutaneous, non-sexual modes often referred to as 'casual' contact (and several anecdotal reports suggest this possibility), there is no credible epidemiological evidence to support this. Fourteen combined surveys, with over 750 individuals with potential exposure through non-percutaneous, non-sexual modes of contact, have failed to find a single case of HIV-1 infection (upper bound of 95% confidence interval = 0.40%), indicating that the risk of transmission by non-percutaneous, non-sexual modes is remote. Given the emotionally charged concerns about transmission of an infection which may end fatally in a high proportion of affected individuals, critical review of the low probability of transmission through non-percutaneous, non-sexual modes is important so that preventive efforts can be focused appropriately.

Epidemiologic Methods↗
PubMed1990

HIV infection risk to nonhealth-care workers.

As has been summarized above, the risk of casual contact transmission of HIV virus is remote. A review of these data should provide reassurance to both workers and management. No evidence exists for direct contact spread through shaking hands and nonsexual touching. There is also no evidence for indirect spread through contact with shared inanimate objects such as typewriters, telephones, computers, water fountains, rest rooms, dining facilities, exercise equipment, bathing facilities, spas, saunas, and swimming pools. In addition, there is no evidence to suggest the airborne spread of HIV, thus there should be no potential risk of transmission through air-conditioning units, air-handling systems, or by sharing the same office space with an infected individual. The fear of AIDS may lead to irrational beliefs and biased perceptions of risk. This, unfortunately, can sometimes lead to discriminatory and inhumane treatment of persons with AIDS. The best way to manage this potential problem in the workplace is through effective educational interventions.

Adult↗
PubMed1990

HIV infection is not associated with Reiter's syndrome: data from the Johns Hopkins Multicenter AIDS Cohort Study.

Reiter's syndrome has been reported to occur in up to 10% of patients with HIV infection. However, no properly controlled epidemiological studies have been conducted to determine whether HIV infection is an independent risk factor or whether the immunodeficiency induced by HIV infection is permissive for infection with other arthritogenic organisms. The prevalence and incidence of Reiter's syndrome were determined in 1133 homosexual/bisexual men enrolled in the Johns Hopkins Multicenter AIDS Cohort Study. There was no difference in the prevalence of Reiter's syndrome at entry into the study in 1984 between 357 HIV-positive and 776 HIV-negative men: five per 1000 in both groups. During 5 years' follow-up, one case of Reiter's syndrome developed among each group of HIV-positive and HIV-negative men. These data fail to support a direct etiological role for HIV infection in the development of Reiter's syndrome.

Adolescent↗
PubMed1990

Selective effect of cefoxitin prophylaxis on post-cesarean-section microbial flora.

A double-blind study was done to test the efficacy of cefoxitin in the prevention of post-cesarean-section infection. The antibiotic was given in three 2-g doses; the initial dose was given immediately after the cord was clamped, and subsequent doses were given four and eight hours later. Cefoxitin prophylaxis significantly reduced morbidity serious enough to require therapeutic antibiotics or to prolong the hospital stay and led to an overall reduction in the anaerobic microbial flora of the endocervix. However, the antibiotic was selective for the overgrowth of enterococci, which were present in nearly half the postoperative cultures of patients who had received the drug. Enterococcal sepsis occurred in one patient, and three other patients had significant bacteriuria and/or urinary tract infections from enterococci. No cefoxitin-resistant strains of Enterobacteriaceae, among species normally sensitive to the drug, were isolated from the stool samples after prophylaxis. The risk of enterococcal colonization and superinfection must be weighted against the benefits of reduction of the infection risk when deciding upon routine antibiotic prophylaxis for cesarean section.

Adolescent↗
PubMed1989

The influence of HIV infection on antibody responses to a two-dose regimen of influenza vaccine.

We studied whether a two-dose regimen of inactivated influenza virus vaccine was more effective than a single dose in inducing protective hemagglutination-inhibition antibody responses in patients infected with human immunodeficiency virus (HIV). Participants included subjects with acquired immunodeficiency syndrome, subjects with acquired immunodeficiency syndrome-related complex, and HIV-seropositive individuals with either lymphadenopathy only or no symptoms. Control subjects were HIV-seronegative heterosexuals and HIV-seronegative homosexuals. Two doses of inactivated influenza vaccine containing 15 micrograms of the hemagglutinin of influenza A/Taiwan/1/86(H1N1), A/Leningrad/360/86(H3N2), and B/Ann Arbor/1/86 were administered intramuscularly in the deltoid region 1 month apart. The second dose of vaccine did not significantly increase the frequency or magnitude of antibody responses of either HIV-seropositive or HIV-seronegative subjects over that achieved by a single dose. The two-dose regimen induced a protective level (greater than or equal to 1:64) of hemagglutination-inhibition antibody to influenza A(H1N1) or (H3N2) virus less often in subjects with symptomatic HIV infection than in uninfected control subjects (39% vs 87% or 46% vs 97%, respectively). Our results suggest that a substantial proportion of individuals with symptomatic HIV infection might remain unprotected from influenza, even after immunization with a two-dose regimen.

AIDS-Related Complex↗
PubMed1989

Transmission of retroviruses by transfusion of screened blood in patients undergoing cardiac surgery.

We determined the rates of seroconversion to human immunodeficiency virus type 1 (HIV-1) and human T-cell leukemia virus Type I (HTLV-I) in a cohort of patients receiving transfusions of blood components screened for antibody to HIV-1. Preoperative and postoperative serum samples were collected from 4163 adults undergoing cardiac surgery who received 36,282 transfusions of blood components. The postoperative samples from all patients were tested for serologic evidence of HIV-1 infection, and those that were positive were compared with the corresponding preoperative samples. One case of HIV-1 transmission by transfusion of screened blood components was identified; two preexisting HIV-1 infections were found. Samples from 2749 patients were tested similarly for serologic evidence of HTLV-I infection; these patients received 20,963 units of blood components. Five new cases and two preexisting cases of HTLV-I infection were detected. The observed risk of HIV-1 transmission by transfusion was 0.003 percent per unit; the risk of HTLV-I transmission was 0.024 percent per unit. We conclude that there is a very small risk of HTLV-I infection from transfused blood products that have been screened for antibodies to HIV-1, but that it is nearly 10-fold higher than the risk of HIV-1 infection.

Acquired Immunodeficiency Syndrome↗
PubMed1989

A large outbreak of epidemic keratoconjunctivitis: problems in controlling nosocomial spread.

Between July 1985 and January 1986, 401 patients with adenovirus epidemic keratoconjunctivitis (EKC) were seen at the Illinois Eye and Ear Infirmary. Of the cases, 110 (27%) were nosocomial; the other 291 patients had community acquired infection. The highest attack rates of EKC occurred in patients attending specialty clinics; the overall attack rate among clinic patients was 4.7/1,000 clinic visits. All nosocomial cases were caused by adenovirus type 8; community acquired cases were a mixture of adenovirus types 8 and 37. Adenoviruses were isolated from conjunctival cultures up to 14 d after the onset of clinical illness. Initial efforts to prevent nosocomial transmission were unsuccessful. However, when a plan to triage all patients on entry to the infirmary and to sort patients and personnel caring for infected patients into cohorts was implemented, nosocomial transmission of EKC was promptly and effectively halted, despite the continuation of the community epidemic for another 4 mo. This outbreak clearly demonstrates the efficacy of rigorous infection control in preventing nosocomial transmission of adenovirus EKC.

Adenoviridae Infections↗
PubMed1989

Neonatal imitation of tongue protrusion and mouth opening: methodological aspects and evidence of early individual differences.

The present work examines imitation of mouth opening and tongue protrusion in 32 full-term infants at three different occasions: When the infants are two to three days, three weeks, and three months old. The analysis focuses (1) on individual differences in imitative behaviour and (2) on how to operationalize the infants' responses. The overall group analysis revealed that imitation of tongue protrusion was statistically significant for both two- to three-day-old and three-week-old infants but not when the children had become three months old. No statistically significant effect was observed for imitation of mouth opening. Two different imitation indexes were constructed in order to assess individual differences in early imitative behaviour. Results show that short-term stability in imitative tendencies exists between the first and second observation. The results further reveal that methodological factors must be seriously considered when studying neonatal imitation: the overall imitation found for tongue protrusion is demonstrated to be dependent on how the infants' responses are coded.

Female↗