Disposition and metabolism of [¹4C]PTZ601 in healthy volunteers.

1. Six healthy male subjects were given a single dose of 500 mg of [14C]PTZ601 (mean radioactivity 79.2 µCi) by intravenous (IV) infusion over 1 h, and observed for 5 days post-dose during which pharmacokinetic (PK) samples were collected. Plasma PTZ601 concentrations and metabolite identification were determined using LC-MS/MS; PK parameters were estimated by non-compartmental analysis. Excretion and mass balance were determined with liquid scintillation analysis and metabolites profiling was characterized by HPLC online radiochemical detection. 2. The disposition of PTZ601 was best described by a fast absorption, followed by a biphasic elimination phase. Peak PTZ601 plasma concentrations were reached within 0.5-1 h. The mean elimination half-life was 1.6 h and clearance was 13 L/h. 3. Recovery of the radioactivity dose was complete (mean 92%). The main route of excretion (parent and metabolites) was the renal route, as urine accounted for 69-77%, while feces only 13-22%, of the total radioactivity. 4. The majority of the drug was excreted in urine as multiple open ring metabolites: M17.3 (oxidative ring-opened product) and M22.2 (di-cysteine conjugate of 17.3); unchanged PTZ601 in urine contributed to 15% of radioactivity. The major metabolites detected in plasma were M17.3, M12.8 (acetylated M17.3), M22.2, and M41.4 (methylated M17.3). 5. PTZ601 was well tolerated.

Increased incidence of sepsis and altered monocyte functions in severely injured type A- glucose-6-phosphate dehydrogenase-deficient African American trauma patients.

OBJECTIVE: To determine whether trauma patients with the common, type A- glucose-6-phosphate dehydrogenase (G6PD) deficiency have an aggravated inflammatory response, increased incidence of septic complications, and/or more profound alterations in leukocyte functions compared with nondeficient trauma patients. SETTINGS: Intensive and surgical care units of a trauma center and flow cytometry and experimental laboratories at a teaching university hospital. DESIGN: Prospective cohort clinical study with measurements on days 2 and 5 postinjury. Monocyte and neutrophil oxidant content, apoptosis, and CD11b expression and plasma cytokine levels were compared between G6PD-deficient and nondeficient patients. PATIENTS: A total of 467 male African American trauma patients were screened for the deficiency. Forty-four type A-202/376 G6PD-deficient patients were identified and enrolled in the study; 43 nondeficient patients were also enrolled and were matched by age, clinical criteria of injury severity, and type of trauma. MAIN RESULTS: After severe injury (Injury Severity Score, > or =16), 50% of the deficient and 6.2% of nondeficient patients developed sepsis with positive bacterial blood cultures. In deficient patients, the frequency of bronchial (75%) and wound infections (25%) was also increased compared with nondeficient patients (32% and 0%). The durations of systemic inflammatory response syndrome, Sepsis Syndrome, and days on antibiotics were three times longer in deficient than in nondeficient individuals. However, adult respiratory distress syndrome occurred in 37% of both groups. Anemia was more severe in the deficient than nondeficient patients from day 10 posttrauma. On day 5, the peroxide content was doubled, apoptosis was decreased, and CD11b expression was increased in monocytes from deficient patients compared with cells from nondeficient patients. On day 5, the plasma interleukin (IL)-10 concentration was significantly lower in deficient than nondeficient patients, whereas tumor necrosis factor-alpha, IL-6, and IL-8 levels were similar. After moderate injuries (Injury Severity Score, 9-16), the deficiency was not associated with adverse clinical effects, and the trauma-induced changes in leukocyte function were similar in deficient and nondeficient patients. CONCLUSIONS: The common type A- G6PD deficiency predisposes septic complications and anemia in trauma patients after severe injuries as defined by an Injury Severity Score of > or =16. This adverse clinical course is accompanied by altered monocyte functions manifested as augmented oxidative stress, a decreased apoptotic response, increased cell adhesion properties, and a diminished IL-10 response.

Phosphorylation of nucleoside analog antiretrovirals: a review for clinicians.

Nucleoside analogs (zidovudine, didanosine, zalcitabine, stavudine, abacavir, lamivudine) have been administered as antiretroviral agents for more than a decade. They undergo anabolic phosphorylation by intracellular kinases to form triphosphates, which inhibit human immunodeficiency virus replication by competitively inhibiting viral reverse transcriptase. Numerous methods are used to elucidate the intracellular metabolic pathways of these agents. Intracellular and extracellular factors affect intracellular phosphorylation. Lack of standardization and complexity of methods used to study phosphorylation in patients limit interpretation of study results and comparability of findings across studies. However, in vitro and in vivo studies give important insights into mechanisms of action, metabolic feedback mechanisms, antiviral effects, and mechanisms of toxicity, and have influenced dosing regimens of nucleoside analogs.

Predicting clinical progression or death in subjects with early-stage human immunodeficiency virus (HIV) infection: a comparative analysis of quantification of HIV RNA, soluble tumor necrosis factor type II receptors, neopterin, and beta2-microglobulin. Multicenter AIDS Cohort Study.

Quantification of human immunodeficiency virus (HIV) RNA by branched-chain DNA signal amplification, measurement of soluble tumor necrosis factor type II receptors (sTNFR-II), neopterin, beta2-microglobulin, or CD4 cell counts can be used to predict the risk of clinical progression or death in HIV infection but have not been compared in the same study. Ninety subjects were categorized into progression groups by their rate of CD4 cell decline and matched into triplets by initial CD4 cell count, age, race, and calendar time. By matched logistic regression, only the sTNFR-II and HIV RNA values were predictive of outcome across the progression groups. Categorization of baseline HIV RNA and sTNFR-II resulted in differences in progression to several clinical outcomes. sTNFR-II concentrations were the only immune marker examined that increased the prognostic utility of HIV RNA determination in early-stage subjects. Further studies in later stages of disease or after therapy are indicated.

The impact of public education videotapes on knowledge about cancer.

BACKGROUND: The purpose of this study was to evaluate, in terms of content and medium, the ability of a videotaped information series to increase the general public's knowledge of cancer. METHODS: In the first phase of the intervention, the videotapes were screened by focus groups, who rated them for length, design, style, and content. In phase two of the study, the videotapes were shown to three random samples of the general population. A portion of each sample was asked to complete a knowledge-survey instrument without viewing the videotapes; a portion was asked to view the tapes before completing the survey instrument. RESULTS: Survey results showed that those who viewed the videotapes had higher knowledge-of-cancer scores than those who did not. CONCLUSION: Community focus groups are inclined to accept cancer information from mediated sources other than those traditionally cited such as physicians and other health professionals.

A 24-week open-label phase I/II evaluation of the HIV protease inhibitor MK-639 (indinavir).

OBJECTIVE: To investigate the safety, pharmacokinetics, and activity of the orally bio-available protease inhibitor MK-639. DESIGN: An open-label Phase I/II trial of medically stable subjects with screening CD4 lymphocyte counts < or = 300 x 10(6)/I and > or = 20,000 HIV RNA copies/ml. Pharmacokinetics were performed at days 1 and 15. In order to better understand the relationships between drug exposure, baseline activity markers, and their changes during the study, mathematical modeling was performed using the traditional sigmoid-Emax relationship of pharmacologic effect and first order inhomogeneous differential equations for a two compartment system. RESULTS: The five men enrolled had extensive prior nucleoside therapy (mean, 32.6 +/- 25.6 months), a low mean CD4 lymphocyte cell count (CD4 count, 66.1 +/- 61 x 10(6)/I and CD4 percentage, 4.4 +/- 3.1%), high soluble tumor necrosis factor-alpha type II (sTNFII) receptor concentration (6.23 +/- 2.76 ng/ml) and high viral load (5.13 +/- 0.46 log10 RNA copies/ ml; geometric mean, 133,941 copies/ml). The drug was well tolerated at a dose of 600 mg every 6 h. The steady state concentrations Cmax and Cmin were 4.94 +/- 2.16 microM and 0.28 +/-0.1 microM, respectively, which are approximately equal to 50 and 3 times the 95% inhibitory concentration (IC95) for clinical isolates, respectively. The mean increase in CD4 cell count was 143 x 10(6)/ (217% increase ), the mean increase in CD4 percentage was 5.2 percentage points (118%), mean decrease in HIV RNA was 1.55 log10 RNA copies/ml (a geometric mean difference of 130,120 copies/ml or 97% decrease) with a slow upward drift on continued therapy to a mean 0.64 log10 RNA copies/ml decrease by week 24 (a geometric mean difference of 103,084 copies/ml or 77% decrease), and a mean decrease in sTNFII receptors of 2.78 ng/ml (45% decrease). The mean CD4 counts per week as a function of the starting CD4 counts fit a sigmoid-Emax relationship (r2 = 0.998, P < 0.0001) with the return of CD4 cells being strongly related to the number of CD4 cells at baseline. Drug exposure as measured by either the total exposure (area under the concentration/time curve) or as the Cmin gave similar significant relationships to the fractional inhibition of HIV generation (r2 = 0.999, P < 0.0001, and r2 = 0.996, P < 0.0001, respectively). CONCLUSIONS: MK-639 appears to have significant dose-related antiviral activity and is well tolerated.

Soluble tumor necrosis factor-alpha receptor type II (sTNF alpha RII) correlates with human immunodeficiency virus (HIV) RNA copy number in HIV-infected patients.

Soluble TNF receptor type II (sTNF alpha RII) levels in serum, CD4 lymphocyte counts, and human immunodeficiency virus (HIV) burdens have each been correlated with HIV disease progression. The level of sTNF alpha RII and HIV RNA was measured in serum and the CD4 lymphocyte count of 25 HIV-infected patients was determined. sTNF alpha RII ranged between 3.019 and 12.57 ng/mL (mean +/- SD, 6.705 +/- 2.5). HIV-1 RNA varied from 960 to 281,160 copies/mL (71,988 +/- 75,684). CD4 cell number was between 4 and 540/microL (181.3 +/- 152.2). Univariate analysis revealed a moderate inverse correlation of sTNF alpha RII with CD4 cell number (r = -.41, P < .05) and a strong positive correlation between sTNF alpha RII and log RNA copy number (r = .62, P < .001). On multivariate analysis, sTNF alpha RII strongly correlated with RNA copy number (P < .01) but not CD4 lymphocyte count. sTNF alpha RII measurements appear to be predictive of clinical outcomes because they are a surrogate indicator of the patients' immunologic response to a virus load.

Primary human immunodeficiency virus type 1 infection: review of pathogenesis and early treatment intervention in humans and animal retrovirus infections.

Primary human immunodeficiency virus type 1 (HIV-1) infection can present clinically as the abrupt onset of a febrile illness resembling acute mononucleosis. The symptoms coincide with high titers of culturable plasma viremia, cell-associated virus, and antigenemia, which rapidly decrease coincident with the emergence of detectable HIV-specific antibody and HIV-specific cytotoxic T lymphocytes. This article reviews the human and animal model data on the virologic and immunologic events that occur during primary HIV-1 and animal retrovirus infections, evaluates the prophylactic treatment experience of retrovirus infections in the animal model, and provides a plausible rationale for treatment intervention of primary HIV-1 infection in humans. Recent work delineating the pathogenesis of primary HIV-1 infection provides insight into the major mechanisms of viral dissemination and host immune response. The results from retrovirus-infected animal models treated with antiviral agents suggests that therapy at the time of viral dissemination may be an effective strategy that may modify disease progression. Clinical trials to evaluate this approach are in progress.

Immune-based therapeutics: scientific rationale and the promising approaches to the treatment of the human immunodeficiency virus-infected individual.

The primary approach to therapy for infection with human immunodeficiency virus (HIV) continues to be centered around antiretroviral agents that have conferred significant clinical benefits. The considerable degree of immunologic dysfunction in HIV infection, however, has led to intense interest in methods of immune stimulation and reconstitution. Immunomodulatory intervention in HIV infection is highly controversial. Over the years a number of immunomodulatory agents--many with only a poor rationale for their clinical use--have been evaluated. In this review we concentrate on immunomodulatory approaches that are currently being investigated. We group these interventions, reviewing the rationale and clinical data for each category: passive immunity (administration of immunoglobulins and use of apheresis), thymic hormone treatment, cytokine treatment (administration of interleukins, tumor necrosis factor, and interferons), adoptive cellular immunity, and therapeutic vaccination. At present, the only interventions supported by data from well-controlled studies are the parenteral administration of interferon alpha to patients with HIV-associated Kaposi's sarcoma and the administration of pooled immunoglobulin (to decrease the rate of bacterial infections) to children who cannot take trimethoprim-sulfamethoxazole. However, several other approaches under development show promise in reversing some of the immune deficits of HIV infection. Clinical evaluation of these approaches should yield valuable insights into the immunopathogenesis of HIV infection, and these insights should facilitate the formulation of new modalities of treatment.

The amino-terminal one-third of pseudorabies virus glycoprotein gIII contains a functional attachment domain, but this domain is not required for the efficient penetration of Vero cells.

We have examined the attachment and penetration phenotypes of several glycoprotein gIII mutants of pseudorabies virus (PRV) and have identified the first one-third of gIII as a region that mediates efficient virus attachment to PK15 and Vero cells. This portion of gIII, amino acids 25 through 157 of the wild-type sequence, appeared to support attachment by binding to heparinlike molecules on cell surfaces. Virions containing the first one-third of gIII were sensitive to heparin competition and showed greatly reduced infectivity on cells treated with heparinase. PRV virions lacking the first one-third of the mature glycoprotein exhibited only residual binding to cells if challenged by vigorous washing with phosphate-buffered saline at 2 h postinfection at 4 degrees C. This residual binding was resistant to heparin competition, and strains lacking the first one-third of gIII were able to infect cells treated with heparinase as effectively as untreated cells. When we determined the penetration phenotypes for each strain, we found that gIII-mediated virus attachment was necessary for timely penetration of PK15 cells but remarkably was not required for efficient virus penetration of Vero cells. Moreover, wild-type PRV was actually prohibited from rapid penetration of Vero cells by a gIII-heparan sulfate interaction. Our results indicate that initial virus binding to heparan sulfate via glycoprotein gIII is not required for efficient PRV infection of all cell types and may in fact be detrimental in some instances.

Pulmonary manifestations of acquired immunodeficiency syndrome.

In at least 65% of patients with acquired immunodeficiency syndrome (AIDS), the lung is the site for life-threatening illness. To establish a basis for understanding the pulmonary pathology of such illness, we first review briefly the effects of the human immunodeficiency virus on the immune system and then review the pathological pulmonary processes occurring in AIDS in terms of their various etiologies: infections, idiopathic processes, and neoplasia. In the section on each etiology, we discuss clinical manifestations, pulmonary pathology, diagnostic findings, and therapeutic options. In the last section, we outline our overall initial diagnostic approach to the patient with AIDS who presents with respiratory symptoms, and we discuss the integration of clinical, laboratory, and radiographic findings.

Endocarditis due to nutritionally deficient streptococci: therapeutic dilemma.

Three cases of endocarditis due to nutritionally deficient (variant) streptococci are presented and the literature is reviewed. In all of the cases reviewed, the patient presented with an indolent subacute course. Prior heart disease was present in 90% of the patients, embolization occurred in 27%, relapse after therapy in 17%, and death in 17%. Bacteriologic failure occurred in 41% of cases, despite sensitivity of the organisms to the antibiotics used in two-thirds of these cases. Combination therapy with penicillin and an aminoglycoside has been recommended previously; however, in 38% of the cases reviewed, bacteriologic failures occurred and the patients required surgery. The results of in vitro antibiotic-sensitivity testing are difficult to interpret and to apply to the expected response to therapy. Further studies on these organisms are needed to reduce the high rates of failure, relapse, and fatality.

Laser vaporization in the treatment of cervical intraepithelial neoplasia.

Ablative cryotherapy and laser vaporization therapy attempt to eradicate the cervical transformation zone in order to eliminate cervical intraepithelial neoplasia and to reduce the risk of invasive cancer. We reviewed the literature on both methods and our own experience with laser therapy. Review of the records of 4,557 initial cryosurgical patients as compared to those of 1,505 initial laser patients revealed cure rates of 12% and 13.8%, respectively (no significant difference, p greater than 0.14). Multiple treatments in 533 cryosurgery and 1,775 laser patients revealed cure rates of 11% and 2.6%, respectively (p less than 0.0001). Enhanced accessibility of the new squamocolumnar junction following laser surgery may result in improved early detection of initial treatment failures and significantly improve the success rates of retreatment. If so, a reduction in the development of invasive cancer in laser-treated patients may occur.

Regeneration of cervical epithelium after laser vaporization.

The process of reepithelialization after laser vaporization of normal cervical squamous epithelium was examined using light and electron microscopy. Tissue specimens were obtained from seven patients at time intervals ranging from seven to 16 days after laser vaporization. Immature squamous epithelium appeared at the edge of the laser crater between seven and 14 days, and by 14 to 16 days, the immature epithelium covered the entire crater area. The observations made in this study concur with those of other studies of the healing process of squamous epithelium, whereby immature cells from the surrounding undamaged epithelium migrate into the damaged area, eventually differentiating into a full thickness of epithelium.