Search PubMed⌕ Search

Biomedical subjects

J W Ward

Publications and source records attributed to J W Ward.

At least 73 records · Page 4Linked to original sources
PubMed1994

Heterosexual transmission of human immunodeficiency virus type 1 from transfusion recipients to their sex partners.

Using lookback procedures and other methods, we identified and then prospectively followed human immunodeficiency virus type 1 (HIV-1)-infected transfusion recipients and their sex partners to determine AIDS incidence and risks of heterosexual transmission of HIV-1. At enrollment, 7 of 32 (21.9%) female partners of male recipients were themselves infected with HIV-1, as compared with none of 14 male partners of female recipients (p = 0.08). No additional episodes of transmission were observed. The prevalence of advanced immunodeficiency at enrollment was similar in male and female recipients. Male recipients with advanced immunodeficiency (CD4+ lymphocyte count < or = 0.20 x 10(9)/L or a history of clinical AIDS) at enrollment were more likely to have infected their female partners (odds ratio = 7.9; p = 0.03) than men with neither condition. Similarly, AIDS-free survival, as estimated by the product-limit method, was lower among male transmitters than among male nontransmitters (p = 0.01). Transmission was not associated with frequency of unprotected vaginal intercourse. Our data suggest that HIV-1-infected men who develop immunodeficiency rapidly are more likely to infect their sex partners and that the greater efficiency of male-to-female HIV-1 transmission is not explained by a greater number of sexual contacts or more advanced immunodeficiency in index subjects.

Adult↗
PubMed1993

Epidemiology of extrapulmonary tuberculosis among persons with AIDS in the United States.

AIDS surveillance data reported to the Centers for Disease Control from January 1981 through December 1991 were analyzed in a study characterizing persons with human immunodeficiency virus (HIV) infection and extrapulmonary tuberculosis (EPTB) in the United States. Among 206,392 persons reported to have AIDS, 4,751 (2.3%) were also reported to have EPTB; of these cases, 4,257 (90%) were reported after September 1987, when the case definition for AIDS was revised to include EPTB. Seventy-six percent of persons in whom AIDS and EPTB were reported after this revision were born in the United States; among these persons, the annual percentage with EPTB in 1988-1991 ranged from 2.3% to 2.5%. The South and the Northeast accounted for 73% of EPTB cases in U.S.-born persons. U.S.-born non-Hispanic blacks (odds ratio [OR], 3.3) and U.S.-born Hispanics (OR, 2.1) were more likely than U.S.-born non-Hispanic whites to be reported as having EPTB. Intravenous drug users were at higher risk (OR, 2.9) than men who reported having had sex with other men. With the resurgence of tuberculosis and the continued expansion of the HIV epidemic, these data provide a useful basis for the targeting of efforts to control tuberculosis and to prevent HIV infection.

AIDS-Related Opportunistic Infections↗
PubMed1993

Hemodialysis and iopamidol clearance after subclavian venography.

RATIONALE AND OBJECTIVES: The dialyzability of iopamidol is unknown and was investigated in patients undergoing long-term hemodialysis for chronic renal failure. METHODS: Ten patients received 30 ml Niopam 300 (Bracco SpA, Milan, Italy) (identical to 18372 mg iopamidol) intravenously into a forearm vein to investigate for occult subclavian stenosis. RESULTS: The elimination half-life of iopamidol before hemodialysis was 69.6 hours and during 4 hours of hemodialysis was 3.5 hours. A single 4-hour hemodialysis cleared 55.7% (95% Ci 51-5-59.8) of the administered dose, while second and third dialyses cleared 25.3% (95% Ci 21.4-29.1) and 10.1% (95% Ci 7.7-12.6) of the administered dose, respectively. Two patients with significant residual urine excretion excreted more than 10% of the administered dose in the urine. For anuric patients, extrarenal clearance provided total body clearance of up to 0.266 L/hr. CONCLUSIONS: Hemodialysis is a rapid and efficient means of clearing iopamidol provided it is performed soon after the contrast study.

Adult↗
PubMed1993

AIDS trends among Hispanics in the United States.

OBJECTIVES: In 1991 the incidence of acquired immunodeficiency syndrome (AIDS) in the United States was 31.6 per 100,000 population among Hispanics and 11.8 per 100,000 among non-Hispanic Whites. The purpose of this study was to further describe the AIDS epidemic among Hispanics by examining differences in risk factors among different Hispanic groups (as defined by birthplace). METHODS: AIDS cases reported to the Centers for Disease Control and Prevention from 1988 through 1991 were reviewed. RESULTS: For men, except for those born in Puerto Rico, the predominant exposure category was male-male sex. The proportion of cases due to injection drug use was 35% among Hispanic men born in the United States, 27% among men born in the Dominican Republic, and 61% among men born in Puerto Rico, but < 10% among other Hispanic men and non-Hispanic White men. For women the predominant exposure category was injection drug use among Hispanics born in the United States (56%) and Puerto Rico (46%) and among non-Hispanic Whites (42%). The proportion of cases associated with injection drug use was significantly lower (< 30%) among other Hispanic women. CONCLUSIONS: AIDS prevention strategies must be geared toward different exposure categories among different Hispanic groups.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Transfusion-associated (T-A)-AIDS in the United States.

To the end of December 1991, 4,709 persons with transfusion-associated (T-A)-AIDS were reported to the Centers for Disease Control and Prevention (CDC) (2.3% of 206,392 adult AIDS cases). Since 1990, the rate of T-A-AIDS case reporting has remained relatively constant at 160-190 cases diagnosed per quarter year. In comparison with other adults with AIDS, those with T-A-AIDS were more likely to be diagnosed with Candida esophagitis and wasting syndrome. Adults with T-A-AIDS tend to be older at diagnosis (mean age 55 years vs. 35 years), white (69% vs. 54%), and female (38% vs. 10%) than other adults with AIDS. However, these demographic differences have decreased over time. The median observed incubation period for T-A-AIDS was 58 months (range 1-154 mo.). Younger adult transfusion recipients had longer incubation periods than older adults. The changing epidemiology of T-A-AIDS reflects, in large part, the effectiveness of prevention strategies.

AIDS Serodiagnosis↗
PubMed1992

HIV infection among patients in U.S. acute care hospitals. Strategies for the counseling and testing of the hospital patients. The Hospital HIV Surveillance Group.

BACKGROUND: Routine, voluntary testing of hospital patients for the human immunodeficiency virus (HIV) has been proposed in order to identify those with early HIV infection in a setting where there is ready access to counseling, appropriate clinical referral, evaluation, and therapy. We studied the pattern of HIV infection among patients in 20 U.S. hospitals, in order to evaluate possible national strategies for the routine, voluntary HIV counseling and testing of hospital patients. METHODS: Blood specimens remaining after clinical use from a systematically selected sample of patients at 20 hospitals in 15 U.S. cities were tested anonymously for antibody to HIV type 1 (HIV-1). Multivariate regression was used to determine which variables best predicted HIV seroprevalence in individual hospitals. Using these data, we estimated the number of HIV-positive patients in all U.S. hospitals and considered the efficiency of routine counseling and testing in different subgroups of patients and hospitals. RESULTS: From September 1989 through October 1991, 9286 of 195,829 specimens (4.7 percent) were positive for HIV-1 in the 20 hospitals. The seroprevalence of HIV at these institutions ranged from 0.2 percent to 14.2 percent. Among HIV-positive patients, 32 percent had symptomatic HIV infection or the acquired immunodeficiency syndrome (AIDS) at the time of admission or evaluation. In the 20 hospitals, HIV seroprevalence was 10.4 times (95 percent confidence interval, 8.8 to 12.0) the AIDS-diagnosis rate (the annual number of patients with new diagnoses of AIDS per 1000 discharges in 1990). In a multivariate model that included 13 hospital-specific variables, only the AIDS-diagnosis rate was associated with the hospital-specific HIV-seroprevalence rate (P less than 0.001). Using these data and the AIDS-diagnosis rates for all U.S. acute care hospitals, we estimated that 225,000 HIV-positive persons were hospitalized (95 percent confidence interval, 190,000 to 260,000) in all 5558 such hospitals in 1990, including 163,000 persons presenting with conditions other than HIV or AIDS (95 percent confidence interval, 130,000 to 196,000). In 1990, in 593 U.S. hospitals with AIDS-diagnosis rates of 1.0 or more per 1000 discharges, HIV testing of patients 15 to 54 years old (3 million patients, or 12.0 percent of all patients in U.S. acute care hospitals) would have identified an estimated 68 percent of all HIV-positive patients (110,000 patients) who were admitted with conditions other than symptomatic HIV infection or AIDS. CONCLUSIONS: We estimate that about 225,000 HIV-positive persons were hospitalized in 1990, of whom only one third were admitted for symptomatic HIV infection or AIDS. Routine, voluntary HIV testing of patients 15 to 54 years old in hospitals with 1 or more patients with newly diagnosed AIDS per 1000 discharges per year could potentially have identified as many as 110,000 patients with HIV infection that was previously unrecognized.

AIDS Serodiagnosis↗
PubMed1992

Analysis of human chest wall motion using a two-compartment rib cage model.

We present a model of chest wall mechanics that extends the model described previously by Macklem et al. (J. Appl. Physiol. 55: 547-557, 1983) and incorporates a two-compartment rib cage. We divide the rib cage into that apposed to the lung (RCpul) and that apposed to the diaphragm (RCab). We apply this model to determine rib cage distortability, the mechanical coupling between RCpul and RCab, the contribution of the rib cage muscles to the pressure change during spontaneous inspiration (Prcm), and the insertional component of transdiaphragmatic pressure in humans. We define distortability as the relationship between distortion and transdiaphragmatic pressure (Pdi) and mechanical coupling as the relationship between rib cage distortion and the pressure acting to restore the rib cage to its relaxed configuration (Plink), as assessed during bilateral transcutaneous phrenic nerve stimulation. Prcm was calculated at end inspiration as the component of the pressure displacing RCpul not accounted for by Plink or pleural pressure. Prcm and Plink were approximately equal during quiet breathing, contributing 3.7 and 3.3 cmH2O on average during breaths associated with a change in Pdi of 3.9 cmH2O. The insertional component of Pdi was measured as the pressure acting on RCab not accounted for by the change in abdominal pressure during an inspiration without rib cage distortion and was 40 +/- 12% (SD) of total Pdi. We conclude that there is substantial resistance of the human rib cage to distortion, that, along with rib cage muscles, contributes importantly to the fall in pleural pressure over the costal surface of the lung.

Adult↗
PubMed1992

Clearance of iopamidol, a non-ionic contrast medium, by CAPD in patients with end-stage renal failure.

In normal healthy subjects radiographic contrast media are cleared by the kidneys with a half-life of approximately 2 h and a total body clearance of 8 l/h. The mechanism of contrast clearance has not been previously investigated in chronic renal failure patients undergoing continuous ambulatory peritoneal dialysis (CAPD). A study was undertaken to investigate the pharmacokinetics of a non-ionic water soluble radiographic contrast medium (iopamidol) in 10 patients stabilized on CAPD. All patients (eight male, two female) aged 22-68 years (median 53 years) had injection of 30 ml of iopamidol 300 via a forearm vein to investigate subclavian vein patency following previous cannulation for haemodialysis. Venous blood samples, CAPD dialysate and urine were collected for seven days post injection. The mean plasma half-life was 37.9 h (SD 10.6) (range 24.1-57.2 h) for the CAPD patients and was greatly prolonged in comparison to healthy subjects. The total body clearance of iopamidol was also greatly reduced (0.377 l/h). CAPD removed an average of 53.6% of the administered dose (range 36.3-80.8%) whilst an average of 26.9% was excreted in the urine (range 1.3-56.3%). The combined renal and dialysate clearance was up to 93% of the administered dose over the period of the study. There is therefore some evidence for a small extra renal clearance of iopamidol in end-stage renal failure patients. This study has shown for the first time that patients with end-stage renal failure undergoing CAPD have significantly delayed elimination of contrast medium. This should be taken into consideration when extensive or prolonged investigations using contrast medium are proposed.

Adult↗
PubMed1991

Risk of human immunodeficiency virus (HIV) transmission by blood transfusions before the implementation of HIV-1 antibody screening. The Transfusion Safety Study Group.

Little information is available regarding the risk of human immunodeficiency virus type 1 (HIV-1) infection for patients transfused before routine anti-HIV-1 screening of blood donors was instituted in March 1985. A model was developed for estimating both the proportion and the number of transfusion recipients in the San Francisco Bay area who were infected by HIV-1 during each of the 7 years preceding routine donor screening for anti-HIV-1. The model is based on analysis of 1) donation histories of HIV-1-infected donors identified at the regional blood center; 2) HIV-1 seroprevalence estimates for homosexual and bisexual men in San Francisco; and 3) HIV-1 infection and survival rates for recipients traced by the Transfusion Safety Study and Irwin Memorial Blood Centers' Look Back Program. The incidence of transfusion-associated HIV-1 infection is estimated to have risen rapidly from the first occurrence in 1978 to a peak in late 1982 of approximately 1.1 percent per transfused unit. The decrease after 1982 coincided with the implementation of high-risk donor deferral measures. It is estimated that, overall, approximately 2135 transfusion recipients were infected with HIV-1 in the San Francisco region alone. This number suggests a higher prevalence of transfusion-associated HIV-1 infection than has been generally recognized and indicates the need for continued tracing of potentially exposed recipients. The data also strongly support the effectiveness of early donor education and self-exclusion measures and emphasize the importance of continued research and development in this area.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Human immunodeficiency virus type 1-infected blood donors: behavioral characteristics and reasons for donation. The HIV Blood Donor Study Group.

Between May 1988 and September 1989, 829 human immunodeficiency virus type 1 (HIV-1)-seropositive donors were identified from 3,919,000 units of blood donated at 20 United States (US) blood centers. Of the 829,512 (62%) were interviewed to assess behavioral characteristics of the largest subgroup, men reporting sex with men, use of the confidential unit exclusion (CUE) and reasons for donation among all donors. Among 216 men reporting sex with men, 97 percent had male and 72 percent had female sexual contact since 1978. The majority identified themselves as bisexual (29%) or heterosexual (26%). Although 61 percent of 512 donors were aware of their risk behavior at donation, including 57 percent of those infected through heterosexual transmission, only 5 percent used the CUE. Reasons for donation included failure to read carefully (46%) or comprehend (15%) the deferral materials, pressure to donate (27%), a desire to be tested for HIV-1 (15%), and a reliance on screening to identify infected blood (10%). Reasons given for a perception of being at low risk included no recent risk behaviors, infrequent risk behaviors, or modification of risk behaviors. To reach high-risk donors, centers should assess whether referral materials provide necessary medical information and are clearly written for persons with diverse cultural and language backgrounds. Staff should be encouraged to avoid the use of culturally stigmatized terms and behaviors that may be perceived as high pressure.

Blood Donors↗
PubMed1990

Prevalence of human immunodeficiency virus type 1 p24 antigen in U.S. blood donors--an assessment of the efficacy of testing in donor screening. The HIV-Antigen Study Group.

BACKGROUND: We performed a multicenter study in 1989 to determine whether screening whole-blood donors for human immunodeficiency virus type 1 (HIV-1) p24 antigen would improve transfusion safety by identifying carriers of the virus who are seronegative for HIV-1 antibody. METHODS: More than 500,000 donations were tested at 13 U.S. blood centers with test kits from two manufacturers. Units found repeatedly reactive were retested in a central laboratory; if the results were positive, they were confirmed by a neutralization assay. A subgroup of units was also tested for HIV-1 by the polymerase chain reaction. Selected donors confirmed or not confirmed as having p24 antigen were contacted for follow-up interviews to identify risk factors and undergo retesting for HIV-1 markers. RESULTS: Positive tests for p24 antigen were confirmed by neutralization in five donors (0.001 percent of all donations tested), all of whom were also positive for HIV-1 antibody and HIV-1 by polymerase chain reaction. Three of the antigen-positive donors had other markers of infectious disease that would have resulted in the exclusion of their blood; two had risk factors for HIV-1 that should have led to self-exclusion. Of 220 blood units with repeatedly reactive p24 antigen whose presence could not be confirmed by neutralization (0.04 percent of the donations studied), none were positive for HIV-1 antibody, HIV-1 by polymerase chain reaction (120 units tested), or virus culture (76 units tested)--attesting to the specificity of confirmatory neutralization. CONCLUSIONS: The finding that no donation studied was positive for p24 antigen and negative for HIV-1 antibody suggests that screening donors for p24 antigen with tests of the current level of sensitivity would not add substantially to the safety of the U.S. blood supply.

Blood Donors↗
PubMed1990

Concordance of polymerase chain reaction with human immunodeficiency virus antibody detection.

To evaluate the correlation of detection of human immunodeficiency virus (HIV) by polymerase chain reaction (PCR) with detection of HIV antibody, 271 simultaneous serum and peripheral blood mononuclear cell samples were examined from 242 persons whose activities placed them at increased risk for HIV infection: 142 from homosexual men, 86 from hemophilic men, and 43 from heterosexual partners of HIV-infected persons. PCR was performed using the gag region primer pair SK38/39 and the env region primer pairs SK68/69 and CO71/72. Amplified HIV DNA was detected using specific oligomer probes. Of 63 HIV antibody-positive samples, 58 (92%) had HIV DNA by PCR. Of 208 HIV antibody-negative samples, 7 (3.4%) had HIV DNA by PCR. On follow-up, 4 of the latter persons were seropositive when next tested; 2 were well and antibody- and PCR-negative; 1 had died of a stroke before retesting. Thus, PCR detects HIV in most antibody-positive persons; detection is increased by use of multiple primer pairs. PCR-positive antibody-negative specimens may indicate HIV infection in which antibody has not yet developed or may be false-positive PCR results. When PCR is discordant with HIV antibody, testing of additional specimens and clinical follow-up are necessary to assess HIV infection status.

Bisexuality↗
PubMed1990

Transplantation in HIV+ patients.

Twenty-five whole-organ recipients treated from 1981 through September 1988 were HIV carriers. Eleven were infected before transplantation, although this was not known until later in 8 recipients. The other 14 were infected perioperatively. Ten of the 25 recipients were infants or children. The organs transplanted were the liver (n = 15), and the heart or kidney (n = 5, each). After a mean follow-up of 2.75 years (range, 0.7-6.6 years), 13 recipients are alive. Survival is 7/15, 2/5, and 4/5 of the liver, heart, and kidney recipients, respectively. The best results were in the pediatric group (70% survival) in which only 1 of 10 patients died of AIDS. In contrast, AIDS caused the death of 5 of 15 adult recipients and was the leading cause of death. Transplantation plus immunosuppression appeared to shorten the AIDS-free time in HIV+ patients as compared to nontransplant hemophiliac and transfusion control groups. Accrual of HIV+ transplant recipients has slowed markedly since the systematic screening of donors, recipients, and blood products was begun in 1985.

Acquired Immunodeficiency Syndrome↗
PubMed1989

The natural history of transfusion-associated infection with human immunodeficiency virus. Factors influencing the rate of progression to disease.

Patients infected by the human immunodeficiency virus (HIV) as a result of blood transfusions are unique in that their dates of infection are well defined and their medical conditions before infection are known. To characterize the natural history of transfusion-associated HIV infection, we studied 694 recipients of blood from 112 donors in whom AIDS later developed and from 31 donors later found to be positive for HIV antibody. Of the recipients tested, 85 were seronegative, 116 were seropositive, and 19 had AIDS. Of 101 HIV-seropositive recipients followed for a median of 55 months after infection, 54 had Centers for Disease Control Class IV disease, including 43 with AIDS. Life-table analysis suggested that AIDS will develop in 49 percent of infected recipients (95 percent confidence limits, 36 to 62 percent) within seven years after infection. As compared with recipients without AIDS, the 43 recipients with AIDS had received more transfusions at the time of infection (median, 21 vs. 7; P = 0.01). HIV-infected blood donors in whom AIDS developed were grouped according to whether AIDS developed within 29 months (the median) after donation (Group 1) or 29 or more months after donation (Group 2). As compared with the 31 recipients of blood from Group 2 blood donors, the 31 recipients of blood from Group 1 donors were more likely to have AIDS four years after infection (49 percent vs. 4 percent; P = 0.005) and illnesses resembling acute retroviral syndrome (14 of 24 vs. 5 of 22; P = 0.03). We conclude that most recipients of HIV-infected blood become seropositive, that AIDS develops in about half these recipients within seven years, and that the risk may be higher when AIDS develops in the blood donor soon after donation.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Duration of human immunodeficiency virus infection before detection of antibody.

To estimate the duration and frequency of the period of HIV infection without detectable antibody, modelling techniques were applied to results of detection of HIV DNA by means of the polymerase chain reaction (PCR) and to data from cases in published reports. PCR was carried out with gag and env region primers on samples from 27 homosexual and 12 haemophilic men for whom stored samples were available from before and after seroconversion; serum was also tested for p24 antigen by antigen-capture enzyme immunoassay. HIV DNA was detectable before seroconversion in 4 men; in all 4 PCR was positive only in the seronegative sample taken closest to the time of seroconversion. In 3 men antigen was detected before seroconversion; in each case HIV DNA was also detected. By a Markov model, the time from infection with HIV (as assessed by detection of HIV DNA) to first detection of HIV antibody was estimated to be 2.4 (SE 2.1) months for the median individual. Modelling of cases of HIV infection with known exposure in published reports gave a median estimate of 2.1 (0.1) months from exposure to antibody detection, and 95% of cases would be expected to seroconvert within 5.8 (0.6) months. HIV infection for longer than 6 months without detectable antibody seems uncommon.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Statistical analysis of the stages of HIV infection using a Markov model.

We use a staged Markov model to estimate the distribution and mean length of the incubation period for acquired immunodeficiency syndrome (AIDS) from a cohort of 603 human immunodeficiency virus (HIV) infected individuals who have been followed through various stages of infection. The model partitions the infected period into four progressive stages: (1) infected but antibody-negative; (2) antibody-positive but asymptomatic; (3) pre-AIDS symptoms and/or abnormal haematologic indicator; and (4) clinical AIDS. We also model a fifth stage: death due to AIDS. The estimated mean (median) waiting times in each stage of infection are stage 1, 2.2 (1.5) months; stage 2, 52.6 (36.5) months; stage 3, 62.9 (43.6) months; and stage 4, 23.6(16.3) months. We estimate the mean AIDS incubation period (from infection to development of clinical AIDS) as 9.8 years with a 95 per cent confidence interval of [8.4, 11.2] years. The paper also considers the estimated density function of the AIDS incubation period and the estimated survival functions for individuals in each stage of infection. This work represents one of the most complete statistical descriptions to date of the natural history of HIV infection.

Acquired Immunodeficiency Syndrome↗