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Dive into the research topics where Timothy J. Holzer is active.

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Featured researches published by Timothy J. Holzer.


Digestive Diseases and Sciences | 1994

Hepatitis C infection in potential recipients with normal liver biochemistry does not preclude renal transplantation

S. Kazi; S. Prasad; Raymond Pollak; Timothy J. Holzer; Cynthia A. Heynen; Alfredo J. Fabrega; David Pitrak; Thomas J. Layden

The hepatitis C virus (HCV) may be an important cause of chronic liver disease in renal transplant recipients. We investigated retrospectively the incidence and outcome of HCV infection in long-term renal transplant recipients and patients on hemodialysis. Stored, pretransplant sera of transplant recipients with normal liver biochemistry at surgery were tested for hepatitis C by a second-generation enzyme immunoassay. Hemodialysis patients were tested by a first-generation enzyme-linked immunosorbent assay (ELISA) against c100-3. We studied 252 renal transplant recipients and 58 hemodialysis patients followed for 65±10 months and 26±6 months, respectively. Fifteen percent (38/252) of the transplant recipients were HCV positive as were 3/58 (5%) of the hemodialysis patients. Over liver disease occurred in 22/252 (8.7%) transplant recipients and none in the hemodialysis group. Thirty-six percent (8/22) of transplant recipients with overt liver disease were HCV positive. No HCV-positive patients died of liver failure. Of six biopsies in the HCV-positive transplant group, two had histological evidence of CAH. CAH was seen in six of eight biopsies in the HCV-negative transplants and two of these latter patients progressed to cirrhosis. No hemodialysis patients had clinical or histological evidence of chronic liver disease. Two HCV-negative transplant patients died of liver failure, while no deaths related to liver disease occurred in hemodialysis patients regardless of HCV status. We conclude that hepatitis C may cause chronic hepatitis in renal transplant patients. However, chronic liver disease in HCV-positive renal transplant recipients appears to be a clinically and histologically benign entity. HCV-positive potential renal allograft recipients with normal liver biochemistry should not be excluded from renal transplantation.


AIDS | 1993

Frequency of cells positive for HIV-1 p24 antigen assessed by flow cytometry

Timothy J. Holzer; Cynthia A. Heynen; Richard M. Novak; David Pitrak; George J. Dawson

ObjectiveMarkers of HIV disease progression such as soluble p24 antigen detection and CD4 lymphocyte depletion are most useful in the later stages of HIV disease and are relatively insensitive as therapeutic monitors. Flow cytometric detection of HIV-1 replication in CD4 lymphocytes was evaluated for use as a marker in predicting disease progression earlier in the course of HIV disease. DesignTo determine whether the number of HIV-1-infected CD4 cells, as measured by p24 antigen detection, can be correlated with disease progression, we used flow cytometry to detect intracellular HIV-1 p24 in CD4 lymphocytes from HIV-1-seropositive subjects at all stages of HIV disease. MethodsMononuclear cells from HIV-1-seropositive subjects and uninfected control subjects were permeabilized and stained with anti-HIV-1 p24 monoclonal antibodies. The cells were then stained with a fluorescein isothiocyanate-conjugated goat antimurine immunoglobulin G followed by a phycoerythrin-conjugated monoclonal anti-CD4 antibody. The percentage of p24-positive CD4 lymphocytes was compared with absolute CD4 counts, soluble p24 detection and Walter Reed classification. ResultsCD4 lymphocyte absolute counts and the percentage of CD4 lymphocytes declined as the Walter Reed classification indicated disease progression. The mean percentage of p24 antigen-positive CD4 lymphocytes increased with disease progression. Only 30% of Walter Reed stage 6 subjects were soluble p24 antigen-positive, whereas 68% were cellular p24 antigen-positive. ConclusionThe percentage of p24 antigen-positive CD4 lymphocytes increased as HIV disease progressed. Flow cytometric quantitation of p24 antigen-positive CD4 cells is a useful method of monitoring in vivo HIV replication and disease progression.


Diagnostic Microbiology and Infectious Disease | 1993

Human neutrophil oxidative response and phagocytic killing of clinical and laboratory strains of Enterococcus faecalis

Richard M. Novak; Timothy J. Holzer; Claudia R. Libertin

Many clinical isolates of Enterococcus faecalis produce a hemolysin/bacteriocin that is plasmid mediated. Recent human epidemiologic studies and animal research suggest that this hemolysin/bacteriocin may enhance the pathogenicity of hemolysin-producing enterococci compared with non-hemolysin-producing strains. These studies determined that clinical strains that produce hemolysin/bacteriocin differed from non-hemolysin-producing clinical and laboratory strains in their ability to induce the production of reactive oxygen intermediates in human peripheral blood neutrophils and in their susceptibility to phagocytic killing in vitro. The induction of superoxide anion generation by neutrophils was demonstrated to be directly proportional to the presence of the hemolysin/bacteriocin plasmid and was transferable to a non-hemolysin-producing laboratory strain by transconjugation. The presence of the plasmid, however, did not effect killing by phagocytic cells in vitro. It is proposed that hemolysin/bacteriocin-producing strains of enterococcus may be more pathogenic due to reactive oxygen product-induced tissue injury in vitro.


Journal of Acquired Immune Deficiency Syndromes | 1991

Seroprevalence of HTLV-I/II and HIV-1 Infection Among Male Intravenous Drug Abusers in Chicago

Joseph R. Lentino; Constance T. Pachucki; Doris M. Schaaff; Melodie R. Schaefer; Timothy J. Holzer; Cynthia A. Heynen; George J. Dawson; Walter Dorus

Summary:We surveyed for serologie evidence of either HIV-1 or HTLV-I/II infection in 387 male veterans who entered into an inpatient drug treatment center. Serum was obtained after receiving written informed consent. Serum specimens were tested by enzyme-linked immunosorbent assay for antibody to HIV-1 and for antibody to HTLV-I/II; sera that were repeatedly reactive were then tested by Western blot (HIV-1/HTLV-I/II) and radioimmunoprecipitation assay (HTLV-I/II). Sixty-five of 387 (16.79%) patients were tested and confirmed as positive for HTLV-I/II only antibodies and 30 of the 387 (7.75%) were positive for HIV-1 only antibodies. An additional nine patients (2.32%) were seropositive for antibodies to both viruses. A statistically significant difference in the CD4/CD8 lymphocyte ratio was associated with HIV-1 sero-positivity. HTLV-I/II seropositivity was strongly associated with black race, age, and duration of i.v. drug use, but not with sexual intercourse as determined by lifetime history of number of sexual partners, incidence of sexually transmitted diseases, type of drug used, or needle-sharing practices.


Digestive Diseases and Sciences | 1994

Diagnosis of acute hepatitis E infection utilizing enzyme immunoassay.

Lino J. DeGuzman; David Pitrak; George J. Dawson; Daniel C. Shin; Timothy J. Holzer; Thomas J. Layden

SummaryAcute hepatitis E infection was diagnosed in a Pakistani immigrant admitted to the University of Illinois Hospital. Utilizing enzyme immunoassay (EIA) tests, specific IgG and IgM class antibodies to three different epitopes of hepatitis E virus (HEV) were detected 12 weeks after the onset of illness and in the early convalescent stage. Sixteen months after the onset of hepatitis, IgM anti-HEV was no longer detectable. Low levels of IgG class anti-HEV antibodies continued to be detected. We demonstrate the utility of the EIA HEV assay to diagnose prospectively acute HEV infection.


AIDS Research and Human Retroviruses | 1990

The Effect of Interleukin 4 (BSF-1) on Infection of Peripheral Blood Monocyte-Derived Macrophages with HIV-1

Richard M. Novak; Timothy J. Holzer; Mark M. Kennedy; Cynthia A. Heynen; George J. Dawson


The Journal of Infectious Diseases | 1991

Low Prevalence of Sexual Transmission of Hepatitis C Virus in Sex Partners of Seropositive Intravenous Drug Users

Constance T. Pachucki; Joseph R. Lentino; Doris M. Schaaff; Melodie R. Schaefer; Cynthia A. Heynen; Timothy J. Holzer; George J. Dawson; Walter Dorus


Journal of Biological Chemistry | 1993

Antiviral phospholipids : anti-HIV drugs conjugated to the glycerobackbone of phospholipids

Charles Pidgeon; Robert J. Markovich; Min D. Liu; Timothy J. Holzer; Richard M. Novak; Kay A. Keyer


AIDS Research and Human Retroviruses | 1990

Discrimination of HIV-2 infection from HIV-1 infection by Western blot and radioimmunoprecipitation analysis.

Timothy J. Holzer; Rhonda G. Allen; Cynthia A. Heynen; Mark M. Kennedy; Mark F. Knigge; Deborah A. Paul; George J. Dawson


The New England Journal of Medicine | 1990

Familial Spastic Paraparesis Syndrome Associated with HTLV-I Infection

Edgar F. Salazar-Grueso; Timothy J. Holzer; Robin A. Gutierrez; James M. Casey; Suresh M. Desai; Sushil G. Devare; George J. Dawson; Raymond P. Roos

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Cynthia A. Heynen

University of Illinois at Chicago

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George J. Dawson

Centers for Disease Control and Prevention

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Richard M. Novak

University of Illinois at Chicago

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Doris M. Schaaff

University of Illinois at Chicago

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Joseph R. Lentino

United States Department of Veterans Affairs

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Thomas J. Layden

University of Illinois at Chicago

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