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Biomedical subjects

C N Oster

Publications and source records attributed to C N Oster.

At least 19 recordsLinked to original sources
PubMed1992

Aerosolized pentamidine and Pneumocystis carinii pneumonia: patient compliance and outcomes.

OBJECTIVE: The study objectives were to compare compliance between every-two-week and every-four-week aerosolized pentamidine regimens, and to determine if patients who were more compliant with the use of aerosolized pentamidine were at decreased risk for developing Pneumocystis carinii pneumonia (PCP). DESIGN: Nonrandomized observational study of patients receiving aerosolized pentamidine for PCP prophylaxis using the hospital pharmacy computer system to document aerosolized pentamidine use and compliance, and the Patient Administration Division's computer to document cases of PCP. SETTING: Tertiary care, US Army medical center. PATIENTS: All patients who were prescribed aerosolized pentamidine (60 mg every two weeks, 300 mg every four weeks, or both) over a 3.5-year period. MAIN OUTCOME MEASURES: Mean percent compliance was determined and compared between every-two-week and every-four-week regimens. The relationship between compliance and cases of PCP as determined using nonparametric statistics. RESULTS: Patients (n = 146) who were prescribed aerosolized pentamidine 60 mg every two weeks were more compliant (p = 0.006) than those prescribed 300 mg every four weeks. In addition, those patients who initially received the 60-mg regimen and were switched to the 300-mg regimen were more compliant when taking the 60-mg dose (p = 0.027). There was no association between compliance with either regimen and cases of PCP. Compliance generally was poor with both regimens. CONCLUSIONS: Patients on every-two-week regimens of aerosolized pentamidine were more compliant than those on every-four-week regimens. However, regardless of compliance, some patients failed aerosolized pentamidine over the 3.5-year period. Other agents that lend themselves to compliance may be more appropriate for PCP prophylaxis than aerosolized pentamidine.

Administration, Inhalation↗
PubMed1992

Prolonged recurrence of pentamidine-induced torsades de pointes.

OBJECTIVE: To report a case of recurrent pentamidine-induced torsades de pointes (TdP) and to review previously reported cases in the literature. DATA SOURCES: Medical records of the subject patient, case reports, and relevant studies identified by MEDLINE. DATA EXTRACTION: Data were abstracted from pertinent published sources by one author and reviewed by the remaining authors. DATA SYNTHESIS: A 43-year-old woman with AIDS experienced pentamidine-induced TdP. TdP and other cardiac arrhythmias recurred repeatedly for 13 days after pentamidine therapy was discontinued and in the presence of normal magnesium and potassium serum concentrations. Infusions of magnesium, lidocaine, and isoproterenol were used to treat the arrhythmias. The exact mechanism of pentamidine-induced TdP has not been clearly established. It is postulated, however, that the similarity of pentamidine's structure to procainamide may contribute to its proarrhythmic effects. The tissue-binding capacity of pentamidine may result in a prolongation of its effects. No distinctive characteristic appears to predispose people to the development of cardiac arrhythmias. Laboratory values that should be monitored include serum magnesium, potassium, and creatinine. The corrected QT interval also should be monitored. CONCLUSIONS: Recurrent arrhythmias may be seen for many days after intravenous administration of pentamidine has been discontinued. Clinicians should consider this phenomenon as they decide how to monitor patients who have received this drug.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Iontophoresis of vinblastine into normal skin and for treatment of Kaposi's sarcoma in human immunodeficiency virus-positive patients. The Military Medical Consortium for Applied Retroviral Research.

BACKGROUND: Patients who test positive for human immunodeficiency virus type 1 (HIV-1) and who have disfiguring and/or painful cutaneous lesions of Kaposi's sarcoma (KS) may not be candidates for systemic chemotherapy and/or immunotherapy. Intralesional vinblastine sulfate, as a single-agent chemotherapeutic drug, has been used with some success to treat KS in patients who are HIV-1 positive. However, some patients may not tolerate the pain associated with injection of vinblastine. Transcutaneous iontophoresis of vinblastine was evaluated for therapy of KS in HIV-1-infected patients. Prior to therapy of patients, we iontophoresed vinblastine into the normal skin of volunteers who were not infected with HIV-1 to document the clinical and histologic features that occurred. OBSERVATIONS: Iontophoresis produced a localized erythematous papular eruption in non-HIV-infected volunteers but not in HIV-1-infected patients. Histologic changes in the biopsy specimens taken from non-HIV-infected volunteers consisted primarily of scattered necrotic keratinocytes and a mild to moderate superficial lymphohistiocytic infiltrate. Thirty-one lesions of KS were treated with partial to complete clearing and symptomatic improvement. CONCLUSION: Clinical and histologic features of iontophoresed normal skin suggest an immunologic mechanism of action. Iontophoresis of vinblastine for KS is well tolerated and results in symptomatic improvement as well as varying degrees of clearing of the lesions.

Adult↗
PubMed1991

Clinical performance of a polymerase chain reaction testing algorithm for diagnosis of HIV-1 infection in peripheral blood mononuclear cells.

The clinical performance of a modified polymerase chain reaction (PCR) testing algorithm was evaluated for confirming the presence of HIV-1 proviral DNA in peripheral blood mononuclear cells. A whole cell lysate, rather than phenol-purified DNA, was used for PCR amplification, under systematically optimized conditions designed and verified within each PCR run to detect as few as 10 copies of proviral DNA. A sequential testing algorithm was designed requiring reactivity in duplicate (with corresponding non-reactivity in negative controls) with at least two sets of primers, before reporting a specimen as HIV-1-positive. In 196 specimens from patients staged according to the Walter Reed staging system, the PCR test sensitivity and the coculture isolation rate (in parentheses) were found to be: 97% (71%), 100% (85%), and 100% (76%) in stage 1, stage 2, and stage 3 specimens, respectively; and 100% (100%) in stage 4, 5, and 6 specimens. Results were uniformly negative for PCR and coculture isolation from 21 blind negative specimens and 105 (negative) donor leukopacks. These data indicate that this PCR testing algorithm is more accurate than tissue culture isolation methods, especially with early stage patients, and results in detection of HIV-1 in virtually 100% of seropositive individuals, with no false positives.

Acquired Immunodeficiency Syndrome↗
PubMed1991

The relationship between outpatient drug costs and disease progression in the human immunodeficiency virus-infected population. The Military Medical Consortium for Applied Retroviral Research.

As the focus of the management of human immunodeficiency virus (HIV) infection turns from the treatment of AIDS to the entire continuum of the disease, projection of long-term healthcare costs becomes increasingly important. Rather than a fulminant disease treated primarily inside the hospital, HIV infection will become a chronic condition requiring years of outpatient monitoring and pharmacologic intervention with attending increases in pharmacy costs. The objective of this study was to characterize outpatient drug costs by Walter Reed (WR) disease stage in order to estimate the association of disease progression and outpatient prescription drug costs. We hypothesized that there was an association between HIV disease progression, measured by the WR Staging Classification System, and outpatient prescription drug costs. Outpatient drug costs were summarized for 190 HIV-positive patients during a three-month period who presented at Walter Reed Army Medical Center for staging and follow-up. The overall median cost per day per patient for all stages was $3.21 (range $0.01-53.45) with wide variation between patients. Daily costs for patients in WR stage V were the greatest (median $9.26). There was a significant association between WR stage of disease and outpatient drug costs (Spearman rho = 0.51, t = 6.9, df = 188, p less than 0.001). The association was not completely linear because costs in WR stage VI were less than WR stages IV or V. Annual extrapolated outpatient drug costs for these 190 patients would be nearly $0.5 million.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Concurrent infection with Leishmania donovani and Leishmania major in a Kenyan patient: clinical description and parasite characterization.

Leishmania isolates aspirated a few months apart from the spleen of an indigenous adult male kala-azar patient from Baringo District, Kenya, were biochemically characterized and compared. The patient lived within a dual focus of L. donovani kalazar and L. major cutaneous leishmaniasis. A primary Leishmania isolate from splenic aspirates was cryopreserved (NLB-294). The patient was treated with sodium stibogluconate for kala-azar and discharged. Three months later, he had clinical relapse and returned for retreatment. During his second visit, the patient participated in a diagnostic study in which urine and nasopharyngeal samples were cultured for leishmaniasis. Urine, nasopharyngeal, and splenic samples were positive for Leishmania. Secondary isolates from splenic (NLB-294-I) and urine (NLB-318) cultures were cryopreserved and characterized by cellulose acetate electrophoresis (CAE) using 20 enzymes. Whereas the urine isolate was typed as L. donovani, the splenic aspirate culture revealed a mixed infection with L. donovani and L. major. The primary isolate (NLB-294) was then characterized and also showed a mixed infection. To exclude the possibility of protein post-translational modifications in electrophoretic assays, the primary and secondary isolates were grown and processed under identical cultural and lysis conditions, and compared using CAE. The results were identical to the first electrophoretic assays showing mixed promastigote banding patterns. Stationary-phase promastigotes of the secondary splenic isolate (NLB-294-I) inoculated subcutaneously, intraperitoneally, and intracardially into Syrian hamsters and BALB/c mice produced both kala-azar and cutaneous leishmaniasis within 6.5 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Post kala-azar dermal leishmaniasis: the Kenyan experience.

Post kala-azar dermal leishmaniasis (PKDL) occurs occasionally after successful cure of visceral leishmaniasis. Twelve patients with diagnosis consistent with PKDL were seen at Clinical Research Centre from 1981 to 1985. Clinical presentation ranged from macular hypopigmented lesion to generalized nodular lesions. All lesions cleared either by self-cure or by treatment with sodium stibogluconate.

Antimony Sodium Gluconate↗
PubMed1991

A retrospective analysis of diseases associated with indeterminate HIV western blot patterns.

Some individuals possess antibodies which react to HIV-1 Western blot proteins in patterns not diagnostic for HIV infection. A retrospective chart review of patients exhibiting such indeterminate HIV Western blots was performed in comparison to a control cohort of sex- and age-matched individuals from the same population of HIV-negative blots to determine if such blots were associated with any specific disease states. Twenty such patients with 25 indeterminate blots among them were found in a total population of 816 (2.5%). GAG-only (core) Western blots comprised the majority 84% (21/25). An indeterminate blot was statistically associated with Hashimoto's thyroiditis (p less than 0.01) and non-Hodgkin's lymphoma (p less than 0.05). Kikuchi's disease and malignant histiocytosis were associated but the numbers were too small to reach statistical significance. The possibility that these diseases are caused by novel retroviruses, cross-reactive with HIV-1, is discussed in lieu of these findings.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Characterization of malaria transmission by Anopheles (Diptera: Culicidae) in western Kenya in preparation for malaria vaccine trials.

Malaria transmission was studied for 33 mo in the villages of Kisian and Saradidi in western Kenya in preparation for field trials of malaria vaccines. Abundance estimates of Anopheles gambiae Giles sensu lato and Anopheles funestus Giles, which constituted over 99% of 26,645 anophelines collected, were compared for all-night biting collections inside houses, outdoors, and in tents. The overall numbers of Anopheles per man-night were 2.3 times greater in Kisian than in Saradidi. For the three types of collections, mean sporozoite rates by dissection ranged from 2.2 to 5.4% for 13,072 Anopheles in Kisian and from 9.9 to 13.6% for 7,058 Anopheles in Saradidi; greater than 90% of the infections were Plasmodium falciparum, either alone or mixed with P. malariae or P. ovale. Heaviest transmission from April to July coincided with the end of the long rainy season. Entomological inoculation rates (EIR) averaged 0.82 infective bites per man per night inside houses in Kisian and 0.65 in Saradidi. Outdoors, EIRs averaged 0.09 in Kisian and 0.52 in Saradidi. In tents, which were evaluated to identify methods for exposing nonindigenous volunteers during vaccine efficacy trials, EIRs were 3.3 and 2.5 times less than inside houses for Kisian (EIR = 0.25) and Saradidi (EIR = 0.26), respectively. Exposure in tents averaged one infective bite every 4.0 d in Kisian and every 3.8 d in Saradidi. The use of tents in vaccine efficacy trials should provide adequate exposure for nonindigenous volunteers. Malaria vaccine trials could be conducted efficiently in western Kenya, with timing dependent upon the intensity of transmission required by vaccine trial objectives.

Analysis of Variance↗
PubMed1990

Isolation of HIV-1 from the blood of seropositive adults: patient stage of illness and sample inoculum size are major determinants of a positive culture. The Walter Reed Retroviral Research Group.

Results of HIV-1 blood cultures from 609 seropositive adults across all stages of illness at the Walter Reed Army Medical Center were reviewed. HIV-1 was isolated by coculturing of patient peripheral blood mononuclear leukocytes (PBMCs) with normal blood donor target PBMCs that had been stimulated with phytohemagglutinin and interleukin-2. The HIV-1 isolation success rate at Walter Reed increased progressively each year from 1986 to 1989. In 1989, HIV-1 was isolated from a single blood specimen from patients in Walter Reed stages 1-2, 3-4, and 5-6 in 75% (49/65), 90% (37/41), and 97% (30/31) of cases, respectively. None of 22 blinded negative control specimens was positive. PBMC cultures from late stage patients regularly became positive within 7 days (92%), compared to only 46% of positive cultures from early stage patients. For most patients, the lowest number of serially diluted PBMCs that resulted in a positive culture was 30,000 patient PBMCs, but the range was 300 to 3 million cells. HIV-1 was isolated less frequently from plasma (5/18, 28%). Plasma viremia was detected only in patients with relatively high titers of infected PBMCs. Forty-six blood specimens from "at-risk" seronegative adults were also cocultured; none was positive.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Human lymphocyte proliferative response to a sporozoite T cell epitope correlates with resistance to falciparum malaria.

To identify vaccine relevant T cell epitopes on the circumsporozoite (CS) protein of Plasmodium falciparum, the lymphocyte proliferative responses to 10 CS protein derived peptides were studied in 28 adult Kenyans, and correlated with resistance to malaria. Eight peptides, six of which were not overlapping, induced proliferation of lymphocytes from one to five volunteers, suggesting either genetic restriction of response to each of the T epitopes, or dominance of some T sites on the immunizing sporozoites. The 28 volunteers were radically cured of malaria and during the next 126 days 25 of the 28 were reinfected. Resistance to malaria was not correlated with antibodies to malaria Ag, but was significantly correlated with lymphocyte responses to CS protein residues 361-380 and 371-390. Among the 25 volunteers who became re-infected with malaria, lymphocytes from only two responded to a peptide including residues 361-380 of the P. falciparum CS protein, and only one to peptide 371-390. In contrast, lymphocytes from all three volunteers who did not become infected responded to peptide 361-380 (p = 0.003), and lymphocytes from two of the three responded to peptide 371-390 (p = 0.023). The significant correlation between proliferation to peptides 361-380 and 371-390 and resistance to malaria suggests that at least one epitope within these overlapping peptides is involved in a protective cellular immune response. The data support inclusion of these residues in future CS protein vaccines.

Adult↗
PubMed1989

Effect of human circumsporozoite antibodies in Plasmodium-infected Anopheles (Diptera: Culicidae).

Human circumsporozoite (CS) antibodies to Plasmodium falciparum were detected in blood meals from 45.0% of 1,547 field-collected Anopheles gambiae Giles sensu lato and Anopheles funestus Giles from western Kenya. Possible effects on malaria infections within the Anopheles host were investigated. Circumsporozoite antibodies were detected in blood meals up to 36 h after feeding. Antibodies crossing the midgut were detected experimentally in hemolymph from 4 to 36 h after feeding; human IgG also was present in hemolymph from fully gravid field-collected Anopheles. Ingestion of high-titer human CS antibodies or 2A10 monoclonal antibody to P. falciparum sporozoites by P. falciparum-infected An. gambiae, 10 d after feeding on an infected human, had no effect on oöcyst maturation, sporozoite rates, or sporozoite loads. Contact between CS antibodies and sporozoites in the hemocoel did not block sporozoite invasion of salivary glands. Human IgG antibodies were detected by an indirect fluorescent antibody technique on salivary gland sporozoites from 83.3% of 114 field-collected Anopheles. In 65.4% of 26 infections, antibodies persisted on sporozoites for at least three days. Thus, a high proportion of naturally infected An. gambiae s.l. and An. funestus in western Kenya transmit sporozoites that are bound with human IgG acquired during previous blood meals. The infectivity of such sporozoites needs to be determined in relation to natural transmission and to the potential use of malaria sporozoite vaccines.

Animals↗
PubMed1989

ELISA method for detecting Plasmodium falciparum circumsporozoite antibody.

An enzyme-linked immunosorbent assay (ELISA) for circulating IgG mouse antibody to Plasmodium falciparum circumsporozoite (CS) protein was modified for use with human sera collected in an area of northern Zambia that was endemic for malaria and from individuals never exposed to malaria. Optimum sensitivity was achieved using Immulon 2 microtitration plates, boiled casein-Tween 20 blocking buffer, and by adding a solution of boiled casein (4 micrograms/ml) to the capture antigen diluent. The results for the detection of anti-CS IgG correlated well with those of sporozoite immunofluorescence antibody assays. Modification of the ELISA method permitted the simultaneous detection of anti-CS IgG and IgM antibody on a single serum sample in the same well of the microtitration plate and the detection of anti-CS IgG antibody in Kenyan dried whole-blood samples collected on filter-paper. The assay has been used to monitor human antibody levels in a phase-I malaria vaccine trial and in longitudinal studies of malaria transmission in Thailand and Kenya.

Adolescent↗