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C M Tsoukas

Publications and source records attributed to C M Tsoukas.

27 records · Page 2Linked to original sources
PubMed1997

N-acetylation among HIV-positive patients and patients with AIDS: when is fast, fast and slow, slow?

BACKGROUND: The discrepancy between genotype and expressed phenotype of the polymorphic N-acetyltransferase (NAT2) has been suggested by separate genotypic and phenotypic studies in populations with human immunodeficiency virus (HIV). Only one study has examined both genotype and phenotype in the same population, and no discrepancies were observed. METHODS: In a cross-sectional study, 105 HIV-positive patients and patients with acquired immunodeficiency syndrome (AIDS) were phenotyped for NAT2 activity with use of caffeine as an in vivo probe; 50 of these patients were also genotyped by restriction mapping and allele-specific amplification. In a longitudinal study, 23 patients were phenotyped at least twice during the 2-year study. RESULTS: The distribution of the NAT2 phenotype among the 105 patients was unimodal and skewed toward slow acetylators as opposed to the bimodal distribution observed in healthy white populations. The genotype distribution was 26:24 slow:fast. There were 18 discrepancies between genotype and phenotype: 12 slow acetylators with fast genotypes and six fast acetylators with slow genotypes. No drug-related effects on NAT2 activity were apparent, but the role of disease progression was evident. Among the slow acetylators whose genotype was fast, the incidence of AIDS was higher (six of 12) than that among the fast acetylators whose genotype was fast (two of 14). Among patients phenotyped more than once (mean time between samples, 10.4 months) changes in phenotype from fast to slow were associated with progression of HIV infection. CONCLUSIONS: Disease progression in HIV infection and AIDS may alter expression of the NAT2 gene. The genotype and the phenotype are not interchangeable measurements. In the HIV population, to know the genotype is useful only if the phenotype is also known and vice versa.

Acetylation↗
PubMed1996

A comparison of two regimens for the treatment of Mycobacterium avium complex bacteremia in AIDS: rifabutin, ethambutol, and clarithromycin versus rifampin, ethambutol, clofazimine, and ciprofloxacin. Canadian HIV Trials Network Protocol 010 Study Group.

BACKGROUND: Bacteremia with the Mycobacterium avium complex is common in patients with the acquired immunodeficiency syndrome (AIDS), but the most effective treatment for this infection remains unclear. METHODS: We randomly assigned 229 patients with AIDS and M. avium complex bacteremia to receive either rifampin (600 mg daily), ethambutol (approximately 15 mg per kilogram of body weight daily), clofazimine (100 mg daily), and ciprofloxacin (750 mg twice daily) (the four-drug group) or rifabutin (600 mg daily), ethambutol (as above), and clarithromycin (1000 mg twice daily) (the three-drug group). In the three-drug group the dose of rifabutin was reduced by half after 125 patients were randomized, because 24 of 63 patients had uveitis. RESULTS: Among 187 patients who could be evaluated, blood cultures became negative more often in the three-drug group than in the four-drug group (69 percent vs. 29 percent, P<0.001). Among patients treated for at least four weeks, the bacteremia resolved more frequently in the three-drug group (78 percent vs. 40 percent, P<0.001). In the three-drug group, bacteremia resolved more often with the 600-mg dose of rifabutin than with the 300-mg dose (P=0.025), but the latter regimen was more effective than the four-drug regimen (P<0.05). The median survival was 8.6 months in the three-drug group and 5.2 months in the four-drug group (P = 0.001). The median Karnofsky performance score was higher in the three-drug group than in the four-drug group from week 2 to week 16 (P<0.05). Mild uveitis developed in 3 of the 53 patients receiving the 300-mg dose of rifabutin, an incidence about one quarter that observed with the 600-mg dose (P<0.001). CONCLUSIONS: In patients with AIDS and M. avium complex bacteremia, treatment with the three-drug regimen of rifabutin, ethambutol, and clarithromycin leads to resolution of the bacteremia more frequently and more rapidly than treatment with rifampin, ethambutol, clofazimine, and ciprofloxacin, and survival rates are better.

AIDS-Related Opportunistic Infections↗
PubMed1996

The use of oral ganciclovir in the treatment of cytomegalovirus retinitis in patients with AIDS.

OBJECTIVE: To recommend the appropriate use of oral ganciclovir as an alternative to intravenous (i.v.) maintenance therapy for cytomegalovirus (CMV) retinitis in patients with AIDS. OPTIONS: i.v. infusion of ganciclovir and foscarnet have been the only approved choices for maintenance therapy until the introduction of oral ganciclovir. OUTCOMES: Ease of administering maintenance therapy and improved quality of life for patients with AIDS. VALUES: The medical advisory group comprised physicians treating patients with AIDS therapy. Ease of administration of maintenance therapy and quality of patients' lives were considered important. BENEFITS, HARMS AND COSTS: Oral ganciclovir is a safe and convenient alternative to i.v. maintenance therapy for patients with CMV retinitis. However, its low bio-availability precludes its use for induction therapy and necessitates careful monitoring for compliance. Compared with i.v. administration of ganciclovir, oral maintenance therapy is cost effective. EVIDENCE: Evidence for the guidelines was gathered from data presented at a symposium on CMV retinitis and oral ganciclovir, clinical trials of oral ganciclovir and input from a visiting expert. It was presented at a meeting of the advisory board whose members are involved in the care of patients with AIDS and the management of CMV retinitis. The guidelines were approved by each member of the advisory board. RECOMMENDATIONS: Diagnosis, treatment and follow-up of CMV retinitis should always be in consultation with an ophthalmologist who is experienced in treating this disease. The patient should be fully informed about the limitations of the oral form of ganciclovir; he or she should be involved in decision making and carefully monitored. Oral ganciclovir should not be used for induction therapy or for maintenance therapy in high-risk patients. VALIDATION: Similar guidelines have been produced in England where the drug has been available since January 1995. SPONSOR: The deliberations of the advisory board and the preparation of this report were funded through an educational grant from Hoffmann-La Roche (Canada).

AIDS-Related Opportunistic Infections↗
PubMed1994

A phase I study of letrazuril in AIDS-related cryptosporidiosis.

OBJECTIVE: The intestinal parasite Cryptosporidium is a common cause of chronic diarrhoea in AIDS patients and is responsible for significant morbidity and mortality. No effective treatment is currently available for this condition. Here we aim to determine the safety, tolerance, and clinical effect of letrazuril in the treatment of AIDS-related Cryptosporidiosis. DESIGN: A prospective, open-label study of letrazuril was performed. SETTING: The study was conducted at the Immune Deficiency Treatment Centre (IDTC) of Montreal General Hospital, a tertiary-care centre with inpatient and outpatient facilities. PARTICIPANTS: All HIV-positive patients presenting to the IDTC between November 1991 and January 1993 who had symptomatic intestinal Cryptosporidiosis were enrolled in this protocol. Sixteen participants entered the study and 15 were available for evaluation, having completed at least 2 weeks on the study medication. INTERVENTIONS: Patients received letrazuril daily in escalating doses of 50 to 100 mg orally for 6 weeks. Clinical and laboratory evaluations were performed weekly during the treatment phase, with a follow-up evaluation 4 weeks after the end of this phase, for a total study period of 10 weeks. MAIN OUTCOME MEASURES: Response to letrazuril was assessed by eradication of Cryptosporidial oocysts from the stool and symptomatic improvement in diarrhoea and abdominal pain. Haematological, biochemical, and electrocardiographic parameters were also studied to evaluate potential toxicities of the treatment. RESULTS: Fourteen evaluable patients had baseline CD4 lymphocyte counts ranging from 3 to 99 x 10(6)/l cells (mean, 30 x 10(6)/l cells). (The fifteenth evaluable patient had a CD4 count 235 x 10(6)/l.) Of these 14 patients, five showed a major response (symptomatic improvement and eradication of Cryptosporidial oocysts from the stool), two had a minor response (symptomatic improvement with persistence of oocysts in stool), and seven had no response to therapy with letrazuril. Seven patients developed a transient drug-related rash. CONCLUSION: Fifty per cent of the AIDS patients in this study experienced an improvement in their Cryptosporidial disease while receiving letrazuril. No serious dose-related toxicities were observed. Larger Phase II trials are needed to evaluate the safety and efficacy of letrazuril in AIDS-associated intestinal Cryptosporidiosis.

AIDS-Related Opportunistic Infections↗
PubMed1994

Markers predicting progression of human immunodeficiency virus-related disease.

Human immunodeficiency virus (HIV) interacts with the immune system throughout the course of infection. For most of the disease process, HIV activates the immune system, and the degree of activation can be assessed by measuring serum levels of molecules such as beta 2-microglobulin and neopterin, as well as other serum and cell surface phenotype markers. The levels of some of these markers correlate with clinical progression of HIV disease, and these markers may be useful as surrogate markers for development of clinical AIDS. Because the likelihood and timing of development of clinical AIDS following seroconversion, for any particular individual, are not readily predictable, the use of nonclinical disease markers has become critically important to patient management. Surrogate markers of HIV infection are, by definition, measurable traits that correlate with disease progression. An ideal marker should identify patients at highest risk of disease progression, provide information on how long an individual has been infected, help in staging HIV disease, predict development of opportunistic infections associated with AIDS, monitor the therapeutic efficacy of immunomodulating or antiviral treatments, and the easily quantifiable, reliable, clinically available, and affordable. This review examines the current state of knowledge and the role of surrogate markers in the natural history and treatment of HIV infection. The clinical usefulness of each marker is assessed with respect to the criteria outlined for the ideal surrogate marker for HIV disease progression.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Lack of transmission of HIV through human bites and scratches.

To examine the relative risk of transmission of the human immuno-deficiency virus (HIV) through bites and scratches, we studied 198 health care workers, 30 of whom were traumatized in this fashion while caring for an aggressive AIDS patient. This violent patient frequently bit or scratched others, his mouth had blood and saliva, while his fingernails were at times soiled with semen, feces, and urine. He was HIV antibody and antigen positive. Although HIV was recovered from his peripheral blood lymphocytes, after 2.5 years of serial follow-up, all traumatized personnel were clinically normal, no HIV was cultured from their blood, and all were HIV antibody and P24 antigen negative. We conclude that this viremic AIDS patient, while producing copious amounts of body fluids, failed to infect those caring for him through bites and scratches. The risk of transmission of HIV through this route under similar conditions should be low.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

The natural history of leukocyturia associated with indinavir treatment in HIV+ individuals.

Urinary complications observed during indinavir treatment of HIV disease are often attributed to indinavir crystalluria. In a prospective study of urinalysis during the first year of indinavir therapy, 5 of 54 asymptomatic HIV+ individuals presented severe leukocyturia (> or =100 cells/HPF) usually accompanying indinavir crystalluria. The clinical course of these 5 individuals, successfully treated for HIV and monitored for an second follow-up year, suggests that recurrence of severe leukocyturia may be an indicator of renal damage, likely tubulointerstitial disease caused by indinavir crystalluria. This is in contrast to the remaining 49 subjects, including those presenting mild leukocyturia, who did not demonstrate any evidence of renal disease. Regular urinalysis is therefore recommended in the clinical management of indinavir-treated individuals to detect early renal damage secondary to indinavir crystalluria and to prevent further renal impairment.

Adult↗
PubMedDate not supplied

Effect of splenectomy on T-cell subsets and plasma HIV viral titers in HIV-infected patients.

OBJECTIVE: In previous studies we have shown that removal of the spleen in HIV-infected people during the asymptomatic phase of disease results in slower time to AIDS and may also result in improved survival. In this paper, we examine whether splenectomy affects lymphocyte counts, T-cell subsets, and HIV plasma viremia in a manner that could explain the clinical benefits associated with this intervention. METHODS: 10 HIV-infected patients who underwent splenectomy and 23 HIV-infected controls with idiopathic thrombocytopenia purpura who did not undergo splenectomy were studied. These groups were compared for changes in cell subpopulations and HIV plasma viremia. RESULTS: Splenectomy resulted in increases in absolute lymphocyte numbers with rises in both CD4 and CD8 counts, whereas CD4 and CD8 percentage levels remained unchanged. In controls, absolute and percentage CD4+ T-cell counts declined with time from date of HIV infection. Plasma viremia decreased more than threefold, the limit of biologic variation, after splenectomy in 4 of 9 subjects and in only 1 of 18 controls. The proportion of subjects exhibiting reduced viremia following splenectomy was greater than that in HIV-infected patients that did not undergo splenectomy (chi 2 test, P = .015). CONCLUSIONS: Improved survival and time to AIDS in splenectomized HIV-infected patients is associated with temporary reduction of plasma viremia and increase in absolute CD4 and CD8 counts. These effects could not be attributed to antiretroviral therapy because subjects were either untreated or treated with antiretroviral monotherapy during the observation period. These observations may have importance in the understanding of T-cell dynamics and the potential for splenectomy as an HIV reservoir-debulking procedure.

Adult↗