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C T Leach

Publications and source records attributed to C T Leach.

10 recordsLinked to original sources
PubMed1995

Association of Epstein-Barr virus with leiomyosarcomas in young people with AIDS.

BACKGROUND: Children with the acquired immunodeficiency syndrome (AIDS) have an unusually high incidence of smooth-muscle tumors (leiomyomas and leiomyosarcomas) in addition to malignant lymphomas. We tested the hypothesis that the smooth-muscle tumors in these children are associated with the Epstein-Barr virus (EBV). METHODS: Tissue specimens of five leiomyosarcomas and two leiomyomas from six children with AIDS were studied for evidence of the human immunodeficiency virus (HIV) and EBV by in situ hybridization and quantitative polymerase chain reaction (PCR). Comparison specimens included samples of leiomyosarcoma and leiomyoma from HIV-negative children. EBV clonality of leiomyosarcomas was determined by Southern blot analysis with oligonucleotide probes for EBV terminal-repeat fragments. Tumor specimens were tested by immunoperoxidase staining for infiltration by B lymphocytes and expression of the EBV receptor. Serologic testing for EBV was performed. RESULTS: In situ hybridization showed EBV genomes in all muscle cells of the five leiomyosarcomas and the two leiomyomas from the six HIV-infected children. Quantitative PCR demonstrated strikingly high levels of EBV in tumor tissue, with as many as 4.3 genome copies per cell. Two colonic leiomyosarcomas obtained from different sites at different times from one patient contained different episomal EBV clones, signifying the presence of distinct monoclonal EBV-related tumors. We found biclonal EBV infection in the leiomyosarcoma of another patient. No EBV was detected in normal muscle or tumor specimens from HIV-negative patients. Immunostaining for the EBV receptor was strongly positive in six of the seven leiomyomas and leiomyosarcomas from the patients with AIDS. CONCLUSIONS: EBV can infect smooth-muscle cells, at least in patients with AIDS, and it may contribute to the pathogenesis of leiomyomas and leiomyosarcomas in children with AIDS. EBV seems to play no part in smooth-muscle tumors in HIV-negative children.

AIDS-Related Opportunistic Infections↗
PubMed1994

Persistent cytomegalovirus infection of semen increases risk of AIDS.

To evaluate if persistent cytomegalovirus (CMV) infection of semen in human immunodeficiency virus type 1 (HIV-1) antibody-positive men increases AIDS risk, serial cultures for CMV every 3-6 months were attempted four or more times from 164 men followed 3 years. CMV was never isolated from 58 men, in 1 or 2 samples from 54 (intermittently positive), and in > or = 3 samples from 52 (persistently positive). The Cox model was used to estimate relative hazards while controlling for CD4 cell number. The relative hazard was 2.9 for those intermittently and 4.0 for those persistently positive (P < .001). No Kaposi's sarcoma occurred in culture-negative men, 3 cases (5.6%) in intermittently positive men, and 4 cases (7.7%) in persistently positive men (P < .04). Persistent CMV in semen increases the hazard of AIDS in HIV-1 antibody-positive men, possibly by activating CD4 cells to produce HIV-1. Thus, control of CMV in HIV-1-infected persons may slow progression to AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Human herpesvirus 6 infection of the female genital tract.

Four of the seven human herpesviruses are recognized to replicate in the female genital tract and may be transmissible to sexual partners and newborn infants. Several of these viruses have also been implicated in the etiology of various human cancers, including tumors of epithelial cell origin. Human herpesvirus 6 (HHV-6) is a newly identified herpesvirus that causes exanthem subitum. The pathogenicity of HHV-6 within the genital tract is largely unexplored. Acellular vaginal secretions from 29 women attending a sexually transmitted diseases clinic were examined for the presence of HHV-6 DNA sequences by polymerase chain reaction. Three samples (10%) were consistently positive for HHV-6 DNA. Since HHV-6 DNA is shed in the genital tract of some women, it is possible that infectious virus is transmissible through sexual contact and to newborn infants by perinatal spread.

Adult↗
PubMed1994

A longitudinal study of cytomegalovirus infection in human immunodeficiency virus type 1-seropositive homosexual men: molecular epidemiology and association with disease progression.

Cytomegalovirus (CMV) isolates from 234 asymptomatic human immunodeficiency type 1 (HIV-1)-positive men were analyzed for molecular relatedness using junctional hybridization. Of isolates shed simultaneously at two or more body sites, 36% from 22 men were different. Of 180 isolates collected from 67 men over 15 months, different strains were isolated serially from 27 men (40%), most from semen. After follow-up of 58 months (mean), the relative hazard of HIV infection progressing to AIDS was 1.8 (95% confidence interval [CI], 0.9-3.7) for men shedding the same strain of CMV and 3.0 (95% CI, 1.4-6.1) for men shedding different strains compared with men not shedding CMV in semen. The prevalence of CMV-specific IgM was higher in men shedding different versus same CMV strains (32% vs. 18%; P = .244). Thus, presence of multiple CMV strains in HIV-1-positive homosexual men is associated with progression to AIDS, possibly via activation of HIV-1-infected CD4 cells.

Cohort Studies↗
PubMed1993

The relationship between T-cell levels and CMV infection in asymptomatic HIV-1 antibody-positive homosexual men.

To investigate the relationship between cytomegalovirus (CMV) infection and progression of HIV-1 disease, a group of 234 asymptomatic, HIV-1 antibody-positive homosexual men were examined for CMV isolation and levels of CMV IgM antibodies, CMV IgG antibodies, and CD4+ and CD8+ T-lymphocytes. CMV IgG antibodies were present in 100% and CMV IgM antibodies in 22% of the men. CMV was isolated from the semen of 45% of the men. No relationship was observed between CMV IgM antibodies and CMV in semen or CD4+ levels. CD4+ cell levels were significantly lower in those from whose semen CMV was isolated. In addition, an inverse relationship was observed between the concentration of CMV in semen and CD4+ levels. We postulate that the seminal tract may be a reservoir for systemic CMV infection in HIV-infected homosexual men. Reinfection from this or other sources may result in recurrent stimulation of HIV-1 replication and lead to a further decline in CD4+ cells. Clarification of whether persistent CMV infection is secondary to HIV-1-induced immunodeficiency or, conversely, promotes a more rapid decline in immunocompetency will require follow-up studies.

AIDS-Related Opportunistic Infections↗
PubMed1992

Relapsing pneumococcal bacteremia in immunocompromised patients.

Relapse of Streptococcus pneumoniae bacteremia after appropriate therapy is thought to be rare, even in immunocompromised patients. We describe three immunodeficient patients who experienced repeated episodes of pneumococcal bacteremia within 8 weeks after receiving appropriate therapy. Serotyping and DNA fingerprinting of respective isolates strongly suggested that each patient's bacteremic relapse was caused by the same pneumococcal strain. Relapsing and recurrent infections with an identical pneumococcal strain, especially in immunodeficient individuals, may be more common than is generally appreciated.

Adult↗
PubMed1989

Use of aminoglycosides during cyclosporine A immunosuppression after liver transplantation in children.

To determine the frequency of renal dysfunction associated with the use of aminoglycosides with cyclosporine A (CyA) in children, the records of 26 consecutive children receiving CyA after liver transplantation were reviewed. Fourteen patients with normal baseline serum creatinine concentrations received an aminoglycoside postoperatively. These children received CyA and an aminoglycoside for 249 days (average, 17.8 days/patient). Forty of the 249 days included treatment with vancomycin or amphotericin B. Twelve children (86%) showed no evidence of renal dysfunction after aminoglycoside therapy. Two children developed renal dysfunction and eventually succumbed. In neither case could aminoglycoside nephrotoxicity be identified as the main cause of renal dysfunction. Multiple other factors, including ischemia and high CyA concentrations, probably contributed to renal deterioration. We conclude that aminoglycosides can be used safely in children receiving CyA following liver transplantation, provided serum CyA concentrations are followed closely and other risk factors for renal dysfunction are minimized.

Acute Kidney Injury↗
PubMed1985

Elastin covalent structure as determined by solid phase amino acid sequencing.

The amino acid sequences of 16 large tryptic fragments of aortic tropoelastin have been determined establishing the presence of several repeating structures: GVP, GGVP, PGVGV, PGVGVA, and AGVPGFGVG. The methodologies for achieving these results by solid phase sequencing are reviewed and also the possible biologic significance of the unusual primary structures of elastin are discussed.

Amino Acid Sequence↗