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Biomedical subjects

D A Katzenstein

Publications and source records attributed to D A Katzenstein.

At least 19 recordsLinked to original sources
PubMed1992

Quantitative RNA and DNA gene amplification can rapidly monitor HIV infection and antiviral activity in cell cultures.

We have developed a quantitative gene amplification procedure to assess the replication of human immunodeficiency virus (HIV) in cell cultures and evaluate the effect of drugs on viral replication. Increases in HIV gag RNA and DNA in phytohemagglutinin-stimulated normal peri-pheral blood mononuclear cells (PBMC) infected with HIV at very low multiplicity of infection paralleled the production of HIV p24 antigen in culture supernatants. Quantitative gene amplification was able to monitor the accumulation of viral nucleic acids in control cultures and demonstrate the effect of various concentrations of azidothymidine (AZT) on the replication of both AZT-sensitive and -resistant strains of HIV. The sensitivity of patient-derived virus strains to AZT could also be successfully measured by these procedures. The results of our studies suggest that quantitative measurement of HIV gag RNA and DNA can be used to monitor the kinetics of viral replication, antiviral activity, viral drug resistance, and mechanism of drug action.

Cells, Cultured↗
PubMed1992

Correlation of morphologic diagnosis of Pneumocystis carinii with the presence of pneumocystis DNA amplified by the polymerase chain reaction.

We compared the presence of P. carinii in clinical specimens as detected by standard cytomorphologic techniques with amplification of P. carinii-specific DNA by the polymerase chain reaction (PCR). Results correlated in 33 of 37 instances (89%): nine specimens were positive by both PCR and morphology; 24 specimens were negative by both techniques. Two specimens from one patient were obtained 3 days apart. The first specimen was both cytologically and PCR negative, while the second specimen was both cytologically and PCR positive for P. carinii. At least in some instances, therefore, PCR is no more sensitive than morphology, and other factors such as specimen adequacy are more important. Twelve of the 24 negative specimens were from patients with prior histories of P. carinii pneumonia, suggesting that recurrent disease may be from reacquisition of organisms in previously exposed individuals, rather than reactivation of latent organisms. Discrepant results included three morphologically negative specimens that were positive by PCR. It remains to be determined whether the increased sensitivity of PCR in these cases is real or artifactual. One morphologically positive specimen was negative by PCR. Polymerase chain reaction correlates well with cytomorphologic diagnosis of P. carinii pneumonia and may be a valuable diagnostic and epidemiologic tool.

Bronchoalveolar Lavage Fluid↗
PubMed1992

Sexual behavior and risk factors for HIV infection in a group of male factory workers who donated blood in Harare, Zimbabwe.

Zimbabwe has experienced a rapid rise in HIV seroprevalence in recent years. As many as 1 million people (10% of the population) are predicted to become seropositive by 2000. We examined social and behavioral factors associated with HIV infection in a case-control study among male factory workers who donated blood before the launching of the AIDS Awareness Campaign. There were 188 subjects: 69 were HIV-positive and 119 were HIV-negative. High-risk behavior was common in both groups. Among seronegative men, 73.1% reported a sexually transmitted disease (STD), 55.5% reported cash payment for sex, and 73.1% had outside girlfriends. Nonetheless, HIV-positive men were more likely to report a history of STD (OR = 3.9; 95% CI = 1.5-11.9), particularly genital ulcers (OR = 2.4; 95% CI = 1.2-4.8), and extramarital partners (OR = 2.8; 95% CI = 1.1-7.1). HIV-positive men reported more lifetime partners (16.5 vs. 12; p less than 0.05) and were less likely to live with their wives (OR = 0.51; 95% CI = 0.23-1.15). Our findings support the importance of genital ulcer as a risk factor and suggest widespread high-risk sexual behavior among urban working-class men.

Adult↗
PubMed1992

Plasma viremia in human immunodeficiency virus infection: relationship to stage of disease and antiviral treatment.

Quantitative culture of human immunodeficiency virus (HIV) was performed on 121 plasma samples from 76 HIV-infected individuals to determine the sensitivity of the assay at different stages of disease and to measure the effect of antiviral therapy on plasma viremia. Plasma virus was detected in 49 of 76 (64%) of patients, primarily those with AIDS and AIDS-related complex (36 of 38) versus asymptomatic subjects (13 of 38) (p less than 0.001, chi 2). Similarly, plasma cultures were more often positive in patients with less than 250 CD4+ T cells per microliter (38 of 40) than in those with greater than 250 CD4+ T cells per microliter (11 of 36) (p less than 0.001, chi 2). Plasma virus cultures were also more likely to be positive in patients with detectable serum p24 antigen (24 of 26) than in those without detectable p24 antigen (25 of 50) (p = 0.0023, chi 2). An effect of zidovudine (ZDV) treatment on plasma viremia was seen in a comparison of treated and untreated patients with less than 250 CD4+ T cells per microliter. Geometric mean titers of plasma viremia from 16 patients treated with ZDV for more than 3 months were significantly lower than titers from 24 untreated patients (10(1.3) versus 10(2.1), p less than 0.05, Student's t test. A comparison of pre- and posttherapy titers in 33 patients receiving antiviral treatment showed that plasma virus was not detectable at either time in 17 patients; there was a fall in plasma virus titer in 12; and titers were unchanged or increased in 4. In patients with advanced disease, plasma viremia is a potential marker of antiviral drug activity.

AIDS-Related Complex↗
PubMed1992

Decrease in HIV provirus in peripheral blood mononuclear cells during zidovudine and human rIL-2 administration.

Quantification of human immunodeficiency virus (HIV) proviral DNA in peripheral blood mononuclear cells (PBMC) was performed in 13 HIV-seropositive asymptomatic individuals during 10-24 months by polymerase chain reaction amplification of multiple half-log dilutions of cellular DNA. At enrollment, subjects had a geometric mean titer of 100 copies of HIV provirus per 10(6) PBMC (mean +/- SD, 2 +/- 0.9 log10). In four untreated individuals there was no significant change in provirus levels during a mean period of 13.3 months. In eight patients treated with zidovudine (ZDV) and human recombinant interleukin 2 (rIL-2), HIV provirus copies declined to 13 per 10(6) cells (1.1 +/- 0.8 log10) at the end of the first course of ZDV and rIL-2 at week 20 (p less than 0.01), and to 40 per 10(6) cells (1.6 +/- 0.9 log10) after 12 months of treatment (p less than 0.04). Subsequent courses, which included 12 weeks of ZDV alone or 4 weeks of IL-2 alone, did not significantly change the already depressed provirus copy numbers. Proviral copy number also remained depressed during drug-free "washout periods" between courses. Finally, we observed a return to a geometric mean of 400 copies per 10(6) cells (2.6 +/- 0.3 log10) a mean of 7.9 months after discontinuation of therapy. Measurement of changes in HIV provirus should provide a direct marker for defining antiviral activity of drugs, biologics, and combination therapy.

DNA, Viral↗
PubMed1991

Detection and quantification of human immunodeficiency virus RNA in patient serum by use of the polymerase chain reaction.

Human immunodeficiency virus (HIV) RNA was detected and quantified in the serum of HIV-seropositive individuals using the polymerase chain reaction (PCR) and a nonisotopic enzyme-linked affinity assay. Of 55 HIV-infected patients who were not receiving therapy, serum HIV RNA was detected in 9 of 19 who were asymptomatic, 11 of 16 with AIDS-related complex (ARC), and 18 of 20 with AIDS, with copy numbers ranging from 10(2) to greater than or equal to 5 x 10(4) 200 microliters of serum based on a relationship between absorbance and known copy number of gag gene RNA. Linear regression analysis demonstrated a correlation between infectious titer in 42 patient sera cocultured with donor peripheral blood mononuclear cells (PBMC) and PCR product absorbance (r = .70, P less than .01). Serum HIV RNA detected by PCR also correlated with serum p24 antigen positivity, CD4 counts less than 400/mm3, and the presence of HIV-related symptoms or disease. Quantification of infectious HIV RNA in cell-free serum by PCR may be useful as a marker for for disease progression or in monitoring antiviral therapy.

AIDS-Related Complex↗
PubMed1991

Detection of human immunodeficiency virus DNA and RNA in semen by the polymerase chain reaction.

Peripheral blood mononuclear cells (PBMC) and semen of 23 men infected with human immunodeficiency virus (HIV) were examined for the presence of HIV DNA and RNA using the polymerase chain reaction (PCR) and a nonisotopic detection assay. None of the men was receiving antiretroviral therapy at the time of collection. Semen samples were separated into cell-free seminal fluid, nonspermatozoal mononuclear cells (NSMC), and spermatozoa. All of the PBMC samples, 17 (74%) of 23 NSMC samples, and none of the spermatozoal samples were positive for HIV gag gene DNA. Of 23 cell-free seminal fluid samples, 15 (65%) were positive for HIV gag gene RNA by PCR. Cell-free HIV RNA was more likely to be present in the semen of men with less than 400 than in those with greater than or equal to 400 cells/mm3 (P less than .04) and was present in all patient with p24 antigen in serum. The presence of HIV DNA in NSMC samples was not related to CD4 cell count, disease status, or the presence of p24 antigen in the serum. This study shows that HIV nucleic acid can be detected by PCR in either the cell-free seminal fluid or NSMC of 87% of semen samples but not in the DNA of spermatozoa from HIV-infected men.

AIDS-Related Complex↗
PubMed1991

Reduction in plasma human immunodeficiency virus ribonucleic acid after dideoxynucleoside therapy as determined by the polymerase chain reaction.

Cell-free HIV RNA in plasma was detected and quantitated after antiviral therapy by the polymerase chain reaction. RNA was extracted from plasma, reverse transcribed to cDNA, amplified by polymerase chain reaction, and quantitated by absorbance based on an enzyme-linked affinity assay. 72 HIV antibody-positive subjects had one plasma sample taken. 39 who were not receiving antiretroviral therapy at the time had a mean plasma HIV RNA copy number of 690 +/- 360 (mean +/- SEM) per 200 microliters of plasma, while 33 subjects who had been receiving zidovudine therapy for a minimum of 3 mo had a mean copy number of 134 +/- 219 (P less than 0.05). 27 additional HIV antibody-positive patients had two plasma samples taken before and 1 mo after initiating dideoxynucleoside therapy. Plasma HIV RNA copy number fell from 540 +/- 175 to 77 +/- 35 (P less than 0.05). Finally, nine of these subjects had two baseline samples obtained before initiating therapy and two posttreatment samples 1 and 2 mo after therapy was begun. Mean plasma RNA copy number declined from 794 +/- 274 to less than 40 (below the lower limit of sensitivity) after 1 mo of therapy, with suppression maintained after 2 mo of therapy. These results suggest that gene amplification can be used to detect and quantitate changes in plasma HIV RNA after dideoxynucleoside therapy. Plasma HIV polymerase chain reaction may be a more sensitive marker to monitor antiviral therapy, particularly in asymptomatic patients where measurement of p24 antigen or quantitative plasma cultures are negative.

CD4-Positive T-Lymphocytes↗
PubMed1990

Possible beneficial effects of neutralizing antibodies and antibody-dependent, cell-mediated cytotoxicity in human immunodeficiency virus infection.

We studied the relationship between early human immunodeficiency virus type 1 (HIV-1) specific immune responses and pathogenesis of infection in participants enrolled in the multicenter AIDS cohort study (MACS). Sera collected at 6-month intervals for 2 years (visit 1-5) from 39 persons who seroconverted by enzyme-linked immunosorbent assay (ELISA) 6 months (visit 2) after enrollment were examined for isotype-specific Western blot reactivity, neutralizing antibodies (NA) against two divergent strains of HIV-1 (HIV-1IIIB and HIV-1RF), and for antibodies capable of participating in antibody-dependent, cell-mediated cytotoxicity (ADCC). These results were compared with changes in CD4+ cell number and episodes of lymphadenopathy. Twenty-five subjects had antibodies of at least one isotype reactive to at least one HIV-1 protein by Western blot at visit 1, before they became ELISA positive. NA reactive with HIV-1IIIB were detected before those reactive with HIV-1RF. NA were first observed in 11 sera at visit 2, in 22 sera at visit 3, and in 3 sera at visit 4; sera from three patients remained nonneutralizing through visit 5. In most cases, NA were detected after a decline in CD4+ cell numbers. The data are consistent with the interpretation that NA develop after about 16 to 18 months of declining CD4+ cell numbers, following which the rate of decline in CD4+ cell numbers slows. In contrast, HIV-1 envelope antigen-specific ADCC responses were first observed in 11 subjects at visit 1 when all 39 were NA and ELISA negative, in 12 subjects at visit 2, in 13 subjects at visit 3, and 1 subject at visit 4. Early ADCC responses were associated with high mean % CD4+ cell numbers and absence of lymphadenopathy throughout the 2-year observation period. Not all subjects who developed ADCC developed NA. In some subjects, ADCC and NA were detectable for the first time at the same visit, for others ADCC was detectable prior to NA, and for a few NA was detectable prior to ADCC. These findings suggest that ADCC and neutralization are mediated by different antibody populations, that they may partially inhibit the progress of HIV-1 infection, and that the late appearance of NA may relate to the failure of immunity to effect recovery from this infection.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Clinical and laboratory characteristics of HIV-1 infection in Zimbabwe.

To define the impact of human immunodeficiency virus (HIV) infection in Africa, clinical and laboratory investigations were conducted on 265 HIV-seropositive outpatients in Zimbabwe. Twenty-four of the study subjects were asymptomatic (ASX), 124 had persistent generalized lymphadenopathy (PGL), and 117 had AIDS-related complex (ARC). HIV infection was assessed by commercial ELISA, Western blots, synthetic peptide ELISA, and measurement of p24 antigen. Serum immunoglobulins, lymphocyte mitogen responses, and CD4+ cell numbers were obtained in 54 sequential patients. Compared to seronegative subjects, mean CD4+ cell numbers were decreased and serum immunoglobulins, particularly IgM and IgG, were increased in all groups of seropositive subjects. Lymphocyte proliferative responses to phytohemagglutinin and concanavalin A decreased progressively in ASX, PGL, and ARC patients and were significantly lower in PGL and ARC patients compared to seronegative controls. Generalized lymphadenopathy was present in 234/265 (88%) of patients. Lymph node biopsies in 100 patients demonstrated follicular hyperplasia in 97 and Mycobacterium tuberculosis in 3. Of 165 patients followed for a median of 6 months, 5 developed the acquired immune deficiency syndrome (AIDS). Symptoms of ARC, low CD4+ cell number, and p24 antigen were predictive of the development of AIDS in Zimbabwe.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Human immunodeficiency virus neutralizing antibodies in sera from North Americans and Africans.

Neutralizing antibodies (NAs) against four isolates of human immunodeficiency virus type 1 (HIV-1) were assayed in HIV-1 antibody positive sera from the United States, Haiti, Zimbabwe, and Zaire. Overall, there were NAs detected in 95, 81, 60, and 73% of sera with reciprocal geometric mean titers (GMTs) of 626, 23, 10, and 20, respectively, against HIV-1MN, HIV-1IIIB, HIV-1RF, and HIV-1Z3. Sera from North America had significantly higher NA titers against HIV-1MN. In each country, the highest antibody titers observed were against the MN strain. Otherwise, sera from the U.S. neutralized most strongly HIV-1IIIB, sera from Zaire neutralized most strongly HIV-1Z3, and sera from Zimbabwe had equal titers against all three viruses. The differences between countries were reflected in analyses of NA titers of subgroups classified on the basis of clinical status, indicating that the differences were not likely to be related to differences in clinical status of the patients being tested. Some of this antigenic variation is reflective of known genetic diversity, while some is not. The results suggest that undefined preserved and variable regions containing neutralization epitope(s) exist. These data do not indicate a need to define antigenic subtypes of HIV-1 at present. The existence of conserved neutralization epitope(s) may indicate the potential for broad immunogenicity of appropriately selected vaccine antigens.

AIDS-Related Complex↗
PubMed1989

Genital ulcers and transmission of HIV among couples in Zimbabwe.

Seventy-five married men found to be positive for HIV-1 in Harare, Zimbabwe, were interviewed in order to define behaviours associated with acquisition of infection and to determine factors associated with transmission of infection to their wives. The majority of infected men reported sexual intercourse with multiple heterosexual partners and female prostitutes, and gave a history of sexually transmitted diseases (STDs). All subjects denied homosexual activity and parenteral drug abuse. Serological testing of the wives of seropositive men showed that 45 (60%) were HIV-antibody-positive. Wives of men with AIDS and AIDS-related complex (ARC) and wives of men who gave a history of genital ulcer disease were more likely to be seropositive. The study demonstrates that HIV-1 infection in Zimbabwe occurs through heterosexual intercourse and is associated with other STDs. In addition, the study shows that male to female transmission of HIV-1 is facilitated by the presence of genital ulcers in infected men.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Microbial flora of the lower genital tract of women in labour at Harare Maternity Hospital. The Puerperal Sepsis Study Group.

The vaginal flora of 214 women who had been referred, in labour, to Harare Maternity Hospital was investigated by examination of vaginal washings and of cervical and urethral swabs taken before and/or after delivery. Four groups of patients were studied: women who had a normal vaginal delivery (NVD), women who were referred because of meconium stained liquor (MSL), women with a history of prolonged rupture of membranes (PROM), and women who were delivered by cesarean section (CS). The first three groups had received no antibiotics during the 7 days preceding specimen collection, while specimens were collected from CS patients only after at least 48 hr of i.v. penicillin and chloramphenicol. T. vaginalis was identified in 19 percent of women, but was not associated with any specific patient group. Chlamydial antigen was detected in 13 percent of patients, but in only one patient (2 percent) in the MSL group. N. gonorrhoeae were isolated from 7 percent of women overall and 25 percent of the strains were penicillinase-producing. Gonococci were recovered significantly more frequently from the PROM patients than from NVD patients as were Group B streptococci and pigment-producing Bacteroides species. Lactobacilli were isolated from only 20 percent of women, despite the use of specific transport and isolation media for these organisms. Specimens from CS patients were taken after these had received parenteral penicillin and chloramphenicol and it was therefore not surprising to find major differences in their vaginal flora with a virtual absence of Gram-positive bacteria, and a high-rate of carriage of multi-resistant coliforms.(ABSTRACT TRUNCATED AT 250 WORDS)

Carrier State↗
PubMed1989

Vaginal flora of women admitted to hospital with signs of sepsis following normal delivery, cesarean section or abortion. The Puerperal Sepsis Study Group.

The microbial flora of the genital tract of 95 women who developed clinical signs of infection within 48 hr of vaginal delivery, Cesarean section delivery or abortion were compared with 111 women who delivered at the same hospital during the same time period but who showed no signs of sepsis. While there were no significant differences in the prevalence of most organisms in the lower genital tract of women with and without sepsis, there was evidence of a higher prevalence of gonococcal, chlamydial and anaerobic infection in the former. Gonococci were isolated from over 20 percent of untreated women with sepsis, more than three times the prevalence in controls. A third of the isolates were penicillinase-producing and another third showed in vitro resistance to penicillin. Chlamydial antigen was detected in 16-20 percent of women with sepsis following vaginal delivery or abortion, compared with 6 percent of controls. Neither gonococcal nor chlamydial infections were significantly associated with sepsis following Cesarean section delivery. Clue cells, indicative of G. vaginalis infection were noted in 20 percent of patients with sepsis compared with 7 percent of controls while amongst the other anaerobes only pigment producing Bacteroides were associated with sepsis. These findings suggest that antepartum investigations for clue cells, chlamydial antigen, gonococci and pigment producing anaerobes may identify patients most at risk from obstetric sepsis in Harare, and identify those for whom prophylactic administration of antibiotics may be of benefit.

Cross-Sectional Studies↗
PubMed1988

Nosocomial adenovirus infections: molecular epidemiology of an outbreak due to adenovirus 3a.

An immunocompromised woman died of disseminated infection due to adenovirus type 3. During her hospitalization and after her death, 38 hospital personnel developed an acute respiratory illness. Adenovirus type 3 infection was documented by culture in 18 of the 38 individuals and by seroconversion in one additional employee. Four of 34 asymptomatic hospital personnel exposed to the index case also seroconverted. Thus, 23 personnel were considered to have confirmed infections, and 22 of these 23 reported direct contact with the index case. Acquisition of infection was associated with the number and type of contacts. Protection against infection was associated with detectable serum-neutralizing antibody in the early serological sample. Restriction enzyme analysis using six different endonucleases indicated that all isolates of virus were type 3a and had identical genetic composition. This study underscores the importance of adenovirus as a cause of nosocomial infection and indicates that genetic analysis of viral DNA is a powerful tool for studying common-source outbreaks.

Adenoviridae Infections↗
PubMed1986

Successful treatment of murine cytomegalovirus disease does not prevent latent virus infection.

9-(1,3-Dihydroxy-2-propoxymethyl)guanine (DHPG), a nucleoside analogue, inhibits the replication of human and murine cytomegalovirus (MCMV) in cell culture. We studied the effects of treatment with DHPG on acute MCMV infection in mice and assessed the impact of drug therapy on the eventual development of latent viral infection. In virus-susceptible Balb/c mice, DHPG treatment limited dissemination of virus infection and prevented death. In sublethal infection of both Balb/c and virus-resistant C3H/St mice, DHPG prevented recovery of infectious virus from visceral organs, including the spleen. Despite these effects of drug treatment on virus replication during acute infection, latent MCMV could be reactivated in vivo by immunosuppression and in vitro by spleen explantation in virtually all mice. These results indicate that successful treatment of MCMV infection and marked suppression of viral replication do not prevent establishment of viral latency.

Acute Disease↗