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Biomedical subjects

T R O'Brien

Publications and source records attributed to T R O'Brien.

At least 55 records · Page 3Linked to original sources
PubMed1996

Kaposi's sarcoma (KS)-associated herpesvirus-like DNA sequences in peripheral blood mononuclear cells: association with KS and persistence in patients receiving anti-herpesvirus drugs.

Herpesvirus-like DNA sequences (KSHV/HHV-8) have recently been described in AIDS-associated Kaposi's sarcoma (KS) lesions. Many questions remain regarding the role of this virus in KS and the therapeutic implications of this finding. In the current study, KSHV/HHV-8 DNA was detected in peripheral blood mononuclear cells (PBMCs) from human immunodeficiency virus (HIV)-infected patients with KS (34/98) more often than in HIV-infected individuals without KS (12/64, P = .03). The detection of KSHV/HHV-8 DNA did not correlate with the CD4 lymphocyte count. Five patients demonstrated KSHV/HHV-8 DNA in their PBMCs during administration of intravenous foscarnet and/or ganciclovir. The continued detection of KSHV/HHV-8 DNA in the PBMCs of patients receiving these anti-herpesvirus drugs has potential implications regarding the virus-cell relationship of KSHV/HHV-8, as well as for the value of these drugs in treating or preventing KS, but additional studies are needed.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Relative resistance to HIV-1 infection of CD4 lymphocytes from persons who remain uninfected despite multiple high-risk sexual exposure.

Some individuals remain uninfected with human immunodeficiency virus type-1 (HIV-1) despite multiple high-risk sexual exposures. We studied a cohort of 25 subjects with histories of multiple high-risk sexual exposures to HIV-1 and found that their CD8+ lymphocytes had greater anti-HIV-1 activity than did CD8+ lymphocytes from nonexposed controls. Further studies indicated that their purified CD4+ lymphocytes were less susceptible to infection with multiple primary isolates of HIV-1 than were CD4+ lymphocytes from the nonexposed controls. This relative resistance to HIV-1 infection did not extend to T-cell line-adapted strains, was restricted by the envelope glycoprotein, was not explained by the cell surface density of CD4 molecules, but was associated with the activity of the C-C chemokines RANTES, MIP-1alpha, and MIP-1beta. This relative resistance of CD4+ lymphocytes may contribute to protection from HIV-1 in multiply exposed persons.

CD4-Positive T-Lymphocytes↗
PubMed1996

Determination of T-lymphocyte subsets on site in rural Tanzania: results in HIV-1 infected and non-infected individuals.

With the FACSCount flow cytometer, counts of CD4, CD8 and CD3 lymphocytes and CD4/CD8 ratios were performed in a rural hospital in Tanzania. A total of 168 subjects (21 HIV-1 seropositive and 147 HIV-1 seronegative) were tested as part of a population-based serosurvey and AIDS education programme; 134 other subjects were hospitalized patients who had signs and symptoms suggestive of AIDS (69 HIV-1 seropositive and 65 HIV-seronegative). Mean values for the 147 HIV-1 seronegative subjects from the local population were 980 CD4 cells (95% CI 930, 1031), 598 CD8 cells (560, 635) and CD4/CD8 ratio 1.78 (1.68, 1.89). Seropositive subjects from the local population had significantly lower CD4 cell counts, higher CD8 counts and a lower CD4/CD8 ratio. CD4 cells were significantly lower and CD8 cells significantly higher in HIV-1 seropositive hospital patients compared to HIV-1 seronegative patients. However, 23 (35%) seronegative hospital patients had CD4 counts lower than 600. These results establish baseline values for the lymphocyte subsets in this population and indicate that this technique can be used in remote areas to monitor progress of HIV-infected individuals.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Evaluation of secular trends in CD4+ lymphocyte loss among human immunodeficiency virus type 1 (HIV-1)-infected men with known dates of seroconversion.

The rate at which immunodeficiency develops in untreated human immunodeficiency virus type 1(HIV-1)-infected persons might be increasing or decreasing over time because of viral evolution or other factors. Beginning in 1984, Multicenter AIDS Cohort Study investigators recruited HIV-1-seronegative homosexual/bisexual men from four US metropolitan areas and examined them semiannually for HIV-1 seroconversion. To assess possible secular changes in the natural history of HIV-1 infection, the authors examined CD4+ lymphocyte data from 354 men who seroconverted between 1984 and 1991. To control for measurement differences among centers and over time, the authors adjusted CD4+ lymphocyte values to those of persistently seronegative participants. CD4+ lymphocyte percentage measurements at the first seropositive visit formed a U-shaped pattern, with the lowest values observed in 1988 and 1989. The authors observed no consistent secular pattern of CD4+ percentages at later visit dates, except that mean CD4+ percentages were consistently lowest in men who seroconverted in 1988. In a proportional hazards model, the time to the adjusted CD4+ lymphocyte count of < 500 cells/mm3 was not associated with the secular time of seroconversion (relative hazard = 1.05, 95% confidence interval 0.97-1.13). The authors' data do not suggest a major change in the natural history of HIV-1 infection of this population.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Idiopathic CD4+ T-lymphocytopenia in HIV seronegative men with hemophilia and sex partners of HIV seropositive men. Multicenter Hemophilia Cohort Study.

Persons with hemophilia or other HIV-1 risk factors may be more likely to have idiopathic CD4+ T-lymphocytopenia (ICL). We determined the frequency of ICL in prospectively followed cohorts of HIV-1 seronegative hemophilic men and seronegative female sex partners of HIV-1 infected hemophilic men, and examined factors potentially associated with ICL. Seven of 304 (2.3%) seronegative hemophilic men and one of 160 (0.6%) female partners met the ICL definition, but the condition resolved for two of the men and for the sole female partner. All five men with persistent ICL had lymphocytopenia (< 1,200 total lymphocytes/microliters) and < 300 total CD4+ lymphocytes/microliters; only one had a low CD4+ percentage. On the most recent measurement, 14.5% of the 304 seronegative hemophilic men had lymphocytopenia. Compared with matched hemophilic controls, men with persistent ICL more often had a history of liver disease (3/5 cases, 0/21 controls, P = 0.007) or splenomegaly (3/5 cases, 4/21 controls; P = 0.04), but not severe hemophilia, greater clotting factor concentrate exposure, high alanine aminotransferase levels, hepatitis B virus antigenemia, or detectable hepatitis C virus RNA in plasma. All five cases and 20/21 controls had antibodies to hepatitis C virus present in their serum. In this cohort of hemophilic men, ICL was related to lymphocytopenia associated with liver disease rather than selective loss of CD4+ lymphocytes.

Acquired Immunodeficiency Syndrome↗
PubMed1995

AIDS and cancer registry linkage: measurement and enhancement of registry completeness. The National AIDS/Cancer Match Study Group.

BACKGROUND AND METHODS: To measure AIDS registry completeness for Kaposi's sarcoma (KS) and cancer registry completeness for KS and non-Hodgkin's lymphoma (NHL), we linked AIDS and cancer registries at selected health departments. RESULTS: We found 10,350 people with KS: 1,935 reported only to the AIDS registry, 1,428 reported only to the cancer registry, and 6,987 reported to both. Ninety-three cases of non-HIV-associated KS were expected. For KS, AIDS registry completeness was 84% [6,987/(6,987 + 1,428 - 93)] and cancer registry completeness was 78% [6,987/(6,987 + 1,935)]. Cancer registry completeness for AIDS-related NHL was 76%. CONCLUSION: If this linking were conducted nationally, about 5,700 additional cases of AIDS and 10,000 additional cases of AIDS-related cancers would be recorded.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Risk factors for postcoital bleeding among women with or at risk for infection with human immunodeficiency virus.

Risk factors for postcoital bleeding were examined in 475 women who were enrolled in a study of heterosexual transmission of human immunodeficiency virus (HIV). In bivariate analyses, history of sexually transmitted diseases (STDs; P = .03), HIV infection (P = .008), and dyspareunia or pain during intercourse (P = .0001) were significant risk factors. In multivariate analysis, the two latter factors remained significant (for HIV, odds ratio [OR] = 2.1, P = .02, 95% confidence interval [CI] = 1.1-4.0; for dyspareunia, OR = 3.5, P < .001, 95% CI = 1.8-6.6), as did the interaction term of STD history and heavy smoking (OR = 2.4, P = .02, 95% CI = 1.2-5.0). Pain during intercourse was the strongest predictor of postcoital bleeding but may be part of the same phenomenon. Similarly, because this study relied on cross-sectional data, the direction of the causal pathway linking HIV to postcoital bleeding cannot be established. However, these data suggest that smoking, a modifiable risk factor, may increase risk of postcoital bleeding and contribute to susceptibility for HIV and other STDs.

Adult↗
PubMed1995

Incidence of neonatal circumcision in Atlanta, 1985-1986.

We reviewed Atlanta area hospital records to determine the following regarding neonatal circumcision: incidence in July 1985; incidence after publicized serious complications of circumcision in August 1985; medical record documentation; and the complication rate. After stratified sampling from hospital birth logs, we abstracted information from medical charts and calculated weighted estimates and P values. The circumcision incidence was 89.3% in July 1985, 87.5% in September 1985, and 84.3% in September 1986. Circumcision was recorded on the medical record face sheet for 84.3% of circumcised boys. The complication rate was 3.1%; no serious complications were recorded. We conclude the following: circumcision incidence was high during the study period; publicity regarding adverse outcomes may have decreased the subsequent incidence of the procedure; hospital discharge data, which rely on medical record face sheet information, underestimate the true incidence of neonatal circumcision; and neonatal circumcision is usually safe, but serious complications may occur.

Adult↗
PubMed1995

Morphologic and morphometric characterization of lung collagen content in clinically normal adult thoroughbreds in race training.

Interstitial and bronchointerstitial pulmonary patterns are commonly observed in thoracic radiographs of Thoroughbreds. Prominent interstitial and bronchointerstitial pulmonary patterns are observed in clinically normal horses, and in horses with respiratory tract disease. Until recently, the relevance of these pulmonary patterns was not known. Previous studies indicated that bronchiolitis, bronchiolar epithelial hyperplasia, epithelial metaplasia, and bronchial arteriolar recruitment correlated strongly with the prominence of the interstitial and bronchointerstitial pulmonary patterns observed radiographically. We examined the content and distribution of collagen in the lungs of 7 clinically normal Thoroughbreds in race training. After standardized fixation, lung tissue was treated with a compound that selectively stains collagen. Standard morphometric techniques were used to determine the volume density of parenchymal tissue and parenchymal airspace, mean linear intercept (estimate of alveolar size), alveolar surface area-to-volume ratio, percentage of parenchyma composed of collagen, percentage of airway wall composed of collagen, and airway wall thickness. These values were compared with radiographic and histopathologic scores obtained from the same horses. The volume density of parenchymal tissue and small airway wall thickness correlated strongly with the prominence of the bronchial and bronchointerstitial pulmonary patterns observed radiographically. Small airway thickness was also highly correlated with the perceived prominence of the interstitial pulmonary patterns observed radiographically, and morphometric estimates of parenchymal tissue and parenchymal collagen. There were also strong correlations between the volume density of parenchymal tissue, the percentage of parenchymal collagen, peribronchiolar mononuclear cell infiltrates, and bronchiolar mucosal plication estimates.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Abdominal radiography for diagnosis of enterolithiasis in horses: 141 cases (1990-1992).

Medical records of 245 horses that had been evaluated by use of abdominal radiography between January 1990 and December 1992 were reviewed. One hundred forty-one horses subsequently had a postmortem examination or surgical exploration performed for definitive lesion diagnosis. The signalment, diagnosis, site, and number of enteroliths were obtained from the medical records. Radiographs were evaluated individually by 3 reviewers for the presence of enteroliths, preferred diagnostic view, evidence of large colon tympany, and film quality. Of the 141 cases reviewed, 66.7% (94/141) had confirmed enterolithiasis. Enteroliths were identified in the right dorsal colon of 59 horses, in the transverse colon of 28, in the small colon of 24, and in the ventral colon of 1 (enteroliths were detected in multiple sites in 12 horses). For the 3 reviewers, mean sensitivity was 76.9% and specificity was 94.4%. Mean positive-predictive value was 96.4%, and negative-predictive value was 67.5%. Cases involving only large colon enteroliths were correctly diagnosed 83.2% of the time, compared with 41.6% of the time for cases involving small colon enteroliths. Enteroliths were evident in 54.8% of the horses with radiographic signs of large colon distention. Fifteen horses had enteroliths in the small colon, 4 in the transverse colon, and 4 in the dorsal colon. Radiographic quality was evaluated and scored as adequate (0), underexposed (-1), overexposed (1), or incomplete. Mean score was -0.5, and there were 21 (14.9%) incomplete studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
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

Characterisation of osseous bodies of the distal phalanx of foals.

The distal phalanx and metacarpal physis of both forelimbs of 32 Thoroughbred foals 3-32 weeks of age were radiographed to identify those limbs with osseous bodies at a palmar process (PP) of the distal phalanx. Osseous bodies (ossicles) were identified radiographically in 19% of the foals. Sixteen of the 32 foals were selected for microradiographic and histological evaluation: 6 foals with radiographic evidence of ossicles and 10 foals without. Fourteen ossicles of the PP were observed radiographically. Ossicles were either a triangular bone fragment at the palmar aspect of the distal angle of the PP, or an oblong bone fragment separated from P3 by a radiolucent line extending 1-3 cm from the incisure of the PP to the solar margin. One foal had radiographic evidence of bilateral distal metacarpal physitis. Seventeen of 35 PPs examined microradiographically were considered normal, in that the dorsal and solar cortices were thin with trabecular bone orientated parallel to the cortical surfaces, and there was a depression in the dorsal cortical surface (i.e. parietal sulcus). Abnormal microradiographic findings in the other 18 PPs included a fracture line extending from the dorsal cortical surfaces and trabecular bridging of the fracture gap. The fracture line was often continuous with the parietal sulcus. Microradiographic evidence of a fracture was found in 75% of foals evaluated. Normal histological findings in 16 PPs included thin dorsal and solar cortices with trabeculae orientated parallel to the cortical surfaces, parallel-fibred dense connective tissue attachments of the deep digital flexor tendon to the solar cortical surfaces, and a neurovascular bundle associated with the parietal sulcus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Radiographic and microscopic correlation of diffuse interstitial and bronchointerstitial pulmonary patterns in the caudodorsal lung of adult thoroughbred horses in race training.

Complete thoracic radiographic examinations were performed on 7 horses ranging in age from 24 to 60 months, followed by in-situ lung fixation. Radiographs were examined by 3 radiologists for the presence, degree and distribution of generalised pulmonary patterns within a region of interest in the caudodorsal lung. Pulmonary tissue was obtained from 12 sites within a designated volume of interest in the caudodorsal lung, corresponding to the area of interest evaluated radiographically, and examined for the presence, character and severity of microscopic lesions. Radiographic findings within the volume of interest consisted of mild to moderate bronchial, bronchointerstitial, or interstitial pulmonary patterns. Interstitial and bronchointerstitial radiographic findings were related to severity of peribronchiolar mononuclear cell infiltrates, the degree of bronchiolar mucosal plication, and alveolar capillary and peribronchial blood vessel erythrocyte content. The severity of the interstitial radiographic pattern was inversely associated with the perceived diagnostic quality of the radiographic examinations. There was no evidence of spatial variation in the severity of the microscopic changes examined in this limited pulmonary region. Inter-rater reliability between radiologists was good in the assessment of diagnostic quality of the radiographic examinations but poor in assessing severity of the primary generalised pulmonary patterns within the radiographic region of interest.

Animals↗
PubMed1993

Sentinel surveillance for HIV-2 infection in high-risk US populations.

OBJECTIVES: We conducted sentinel surveillance in persons practicing behaviors known to transmit retroviruses to determine the US presence and extent of human immunodeficiency virus type 2 (HIV-2). METHODS: Sentinel surveillance for HIV-2 was conducted by testing 31,533 anonymous blood specimens from patients at sexually transmitted disease clinics, injecting drug users at treatment centers, and clients at HIV counseling and testing sites in 14 US cities where West African immigrants often settle. Specimens were tested by HIV-1 and HIV-2 whole virus and synthetic peptide enzyme immunoassay and confirmed by HIV-1 and HIV-2 Western blots. RESULTS: Nearly 10% of 31,533 sera were positive for HIV-1. Two heterosexual Black male sexually transmitted disease patients were infected with HIV-2. One of the HIV-2 positive specimens did not cross-react on HIV-1 enzyme immunoassay screening. One client had antibodies consistent with malarial infection in West Africa; the other, who had syphilis, did not have antibodies to malaria or to any of 20 arboviruses present in Africa. CONCLUSIONS: Clinics serving clients from HIV-2 endemic areas should test persons practicing risk behaviors for both HIV-1 and HIV-2. Sentinel surveillance for HIV-2 serves as an early warning system for the possible spread of this virus in the United States.

Adult↗
PubMed1993

Prevention of heterosexual transmission of human immunodeficiency virus through couple counseling.

In the absence of an effective vaccine, behavior change remains the most effective means to prevent the spread of HIV. We examined behavior change over time and rates of HIV seroconversion in a cohort of HIV individuals and their heterosexual partners recruited since 1985. Participants were recruited from various HIV counseling and testing sources throughout California and were usually interviewed and tested in their own homes. Couple counseling and risk assessments were conducted at average intervals of six months. Data from 144 couples who were discordant for HIV serostatus are reported. Of the index cases, 78% were men. Most male index cases were bisexuals, and most female index cases were infected through heterosexual intercourse with a previous sexual partner. The mean duration of the relationship for the couple at intake was 5.6 years. Both condom use and sexual abstinence increased over time (p < 0.001 for both), and most behavior change occurred between intake and first follow-up visit. We observed no seroconversion after 193 couple-years of follow-up. Couple counseling in combination with social support appears to be an effective means to promote and sustain behavior change among HIV-infected individuals and their heterosexual partners.

Adolescent↗