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Biomedical subjects

E H Kaplan

Publications and source records attributed to E H Kaplan.

At least 19 recordsLinked to original sources
PubMed1996

Initial results of a phase II trial of high dose radiation therapy, 5-fluorouracil, and cisplatin for patients with anal cancer (E4292): an Eastern Cooperative Oncology Group study.

PURPOSE: A prospective clinical trial was performed to assess the response and toxicity associated with the use of high dose radiation therapy, 5-fluorouracil, and cisplatin in patients with anal cancer. METHODS AND MATERIALS: Patients with anal cancer without distant metastasis were eligible for this study. Radiation therapy consisted of 59.4 Gy in 33 fractions; a 2 week break in treatment was taken after 36 Gy had been given. A treatment of 5-fluorouracil, 1,000 mg/m2 per day intravenously, was given for the first 4 days of radiation therapy, and cisplatin, 75 mg/m2 intravenously, was given on day 1 of radiation therapy. A second course of 5-fluorouracil and cisplatin was given after 36 Gy of radiation, when the radiation therapy was resumed. RESULTS: Nineteen patients entered this study and received treatment. Thirteen (68%) had a complete response, 5 (26%) had a partial response, and 1 (5%) had stable disease. The patient with stable disease and one of the patients with a partial response had complete disappearance of tumor more than 8 weeks after completion of radiation therapy. Fifteen patients had toxicity of Grade 3 or higher: the worst toxicity was Grade 3 in eight patients, Grade 4 in six patients, and Grade 5 in one patient. The most common form of toxicity of Grade 3 or higher was hematologic. The one lethal toxicity was due to pseudomembranous colitis, which was a complication of antibiotic therapy for a urinary tract infection. CONCLUSION: Radiation therapy, cisplatin, and 5-fluorouracil resulted in an overall response rate of 95%. Significant toxicity occurred, an indication that this regimen is near the maximal tolerated dose. A Phase III clinical trial is planned in which radiation therapy, cisplatin, and 5-fluorouracil will be used as an experimental arm.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

HIV incidence among New Haven needle exchange participants: updated estimates from syringe tracking and testing data.

This article provides updated estimates of the rate of new HIV infections among participants in New Haven's legal needle exchange program from syringe tracking and testing data. We previously reported that based on data collected from November 1990 through May 1992, the maximum likelihood incidence rate was zero with a 95% confidence interval of 0-10.2 new infections per 100 drug injectors per year. Expanding this data set through August 1993, the same statistical methods yield a maximum likelihood estimate of 1.63 new infections per 100 drug injectors per year with a 95% confidence interval of 0-7.2. Given these data, the null hypothesis of no new infections cannot be rejected, providing further support for the efficacy of New Haven's needle exchange program.

Confidence Intervals↗
PubMed1995

An analysis of the process of human immunodeficiency virus sexual risk behavior change.

Few studies have tried to identify the process of risk behavior change. In this paper, we present a method for the analysis of the process of risk behavior change; the methodology involves using time series data to form transition probability matrices. We apply the method to human immunodeficiency virus (HIV) sexual risk behavioral data from a cohort of gay men in Amsterdam. We determine the process of risk behavior change in this cohort, and we demonstrate that it is not possible to deduce the process simply from an examination of the static pattern. Our results imply that the risk behavior change that is observed in this cohort may be viewed as a homogeneous one-step Markovian process. This process of risk behavior change has implications for the long-term prediction of HIV seroconversion rates and for the design and evaluation of HIV behavioral intervention studies and vaccine trials. Our results also have implications for the interpretation of relapse behavior.

Cognition↗
PubMed1995

How many HIV infections are there in Israel? Reconstructing HIV incidence from AIDS case reporting.

BACKGROUND: The reporting of AIDS cases to Israel's Ministry of Health is believed to be accurate, but the completeness of HIV surveillance is unknown. We implement a model that reconstructs HIV incidence in Israel from AIDS case reports excluding Ethiopian immigrants. METHODS: We apply the well-known method of backcalculation to AIDS cases reported to the Ministry of Health. The data are adjusted statistically to account for reporting delays and the elimination of AIDS Related Complex reporting. The analysis also accounts for the impact of differential administration of antiretroviral therapy to HIV-infected persons over time. RESULTS: Excluding Ethiopian immigrants, we find that the cumulative number of HIV infections reported to the Ministry of Health through December 1993 (1,011) is not statistically different from the model's estimate of 922 (z = 1.04; p = 0.30), though the reported number of new infections in recent years exceeds the modeleted rate. CONCLUSIONS: The low HIV incidence estimated among non-Ethiopian Israelis is consistent with other studies of sexually transmitted diseases and HIV-related risky behavior in Israel. This result counters the hypothesis that an explosive HIV epidemic will occur. That the number of recently reported new infections exceeds the estimate from the model could indicate that the reporting system is catching up with the extant spread of disease, or that the model is missing some aspect of the dynamics of HIV in Israel. We suggest that comparing future annual HIV incidence rates to the model's upper bound of 80 infections per year will enable resolution of this issue over time.

Acquired Immunodeficiency Syndrome↗
PubMed1994

A decline in HIV-infected needles returned to New Haven's needle exchange program: client shift or needle exchange?

The New Haven needle exchange program experienced a significant decline in the fraction of returned needles containing human immunodeficiency virus 1 (HIV-1) proviral DNA. Is this decline due to the operations of the needle exchange or to a shift in clients? Analysis of demographic and behavioral data revealed that only one variable, the race of participating clients, changed significantly over time. However, HIV-1 prevalences in needles given to Whites and to non-Whites were not statistically different. Thus, client shift cannot be responsible for the decline in the observed HIV prevalence in needles. Instead, needle circulation times were a significant predictor of HIV prevalence.

Connecticut↗
PubMed1994

HIV incidence among needle exchange participants: estimates from syringe tracking and testing data.

This paper develops a statistical procedure for estimating the HIV infection rate among needle exchange clients without using any self-reported information. Instead, data are accumulated by following the distribution and return of sequentially labeled syringes and by testing a sample of returns for the presence of HIV-1 proviral DNA using polymerase chain reaction. For each drug injector in the sample, a maximum likelihood change point model is constructed to determine if a statistically significant upward shift in the fraction of needles testing HIV positive is evident, as would occur if the drug injector in question became infected. A second maximum likelihood model is formulated to estimate the HIV incidence rate among needle exchange participants by aggregating the individual change point results. When these methods are applied to the syringe tracking and testing data collected to evaluate the legal needle exchange program in New Haven, Connecticut, the maximum likelihood incidence estimate equals zero, with a 95% confidence interval of 0-10.2 new infections per 100 drug injectors per year. Given these data, we cannot reject the null hypothesis that no new infections have occurred among needle exchange participants between November 1990 and May 1992.

Connecticut↗
PubMed1993

Needle exchange decreases the prevalence of HIV-1 proviral DNA in returned syringes in New Haven, Connecticut.

PURPOSE: To report on the deployment of the syringe tracking and testing system in the New Haven needle exchange program, which is the first federally funded evaluation of a needle exchange program conducted in the United States. PATIENTS AND METHODS: A legal needle exchange for intravenous drug users began in New Haven, Connecticut, in November 1990. All syringes distributed by the program received unique tracking codes. Syringes were tracked and HIV-1 proviral DNA prevalence in returned syringes was assessed using polymerase chain reaction and Southern blotting. RESULTS: At the outset of the program, the prevalence of HIV-1 proviral DNA in syringes exceeded two thirds. Prevalence decreased rapidly to less than 45% during the first 3 months of the program and remained at this level for the following 10 months. During the periods of decreasing prevalence and subsequent steady state, no changes in the demographics of program participants or in the drug use habits of newly enrolling clients that could account for the decrease in HIV-1 prevalence in needles were detected. In addition, the program referred almost 20% of its clients to drug treatment programs. CONCLUSION: The needle exchange program in New Haven has decreased the percentage of syringes testing positive for HIV-1 proviral DNA among needle exchange clients while simultaneously serving as an entry point for drug treatment.

Analysis of Variance↗
PubMed1993

Cutaneous T-cell lymphomas.

Cutaneous T-cell lymphoma, which usually presents as mycosis fungoides or Sézary syndrome, remains a mostly incurable, yet highly treatable group of diseases. The myriad of active therapies continues to grow, and new insights into the mechanism of systemic and topical therapies are being elucidated. Multimodality treatment initiated for early-stage disease may help improve long-term survival. The need for randomized prospective trials is obvious and should become a priority. Further development of molecular genetic techniques and cell-surface phenotyping has enhanced our understanding of these diseases and will hopefully allow for the development of more effective and specific treatments.

Humans↗
PubMed1993

The epidemiological and economic consequences of AIDS clinical trials.

The Food and Drug Administration (FDA) must manage the delicate balance between speed and safety in the evaluation and approval of new drugs. To explore how these competing obligations might be formalized with respect to the AIDS epidemic, we present a simple decision-theoretic optimization model of the clinical trials process against a backdrop of HIV transmission. Our framework sheds light on such issues as the economic consequences of decisions, the potential savings of a new therapy, the costs to society of delay, the value of better information, and how and when to undertake a clinical trial. We believe that this article represents a first effort to unravel the tangled web of epidemiological, economic, and statistical considerations that plague this policy issue.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Selection bias in in vitro fertilization programs.

Pregnancy rates per cycle reported from different in vitro fertilization-embryo transfer programs vary widely. While several programs have reported constant pregnancy rates per cycle, others report declining pregnancy rates. Selection biases at the point of entry and between cycles are discussed as possible explanations of these discrepancies.

Bias↗
PubMed1992

Asymptotic worst-case mixing in simple demographic models of HIV/AIDS.

The majority of published modeling work regarding the impact of mixing patterns among subgroups on the spread of HIV infection assumes either that the overall population size remains constant, the aggregate immigration to the population occurs at a constant annual rate, or that no immigration occurs and the population in question declines due to HIV or other causes. In this paper, immigration rates are modeled as simple functions of population size and may be interpreted as aggregate birth rates. This assumption implies asymptotic exponential growth in the disease-free population as long as per capita birth rates exceed per capita mortality rates. The introduction of HIV infection to such a population may change this situation, and the asymptotic population growth rate can be reduced substantially as a result. The specific manner in which this occurs depends in part upon difficult to observe mixing patterns among those with different sexual activity rates. Rather than attempting to explicitly model a variety of mixing patterns, a bound on the impact of worst-case mixing is produced, where "worst case" refers to the mixing pattern that maximizes the asymptotic prevalence of infection, which is equivalent to minimizing the asymptotic population growth rate. These new techniques are illustrated with a numerical example.

Acquired Immunodeficiency Syndrome↗
PubMed1992

R0 bounds for worst-case endemic mixing models.

Upper and lower bounds are presented for the worst endemic prevalence possible in nonrandom mixing models. The bounds require only the value of the reproductive number R0 for the corresponding homogeneous epidemic model. For R0 values of 4 or larger, the difference between the upper and lower bounds on the worst-case prevalence is at most five percentage points.

Epidemiology↗
PubMed1992

Immunoscintigraphy performed with In-111-labeled CYT-103 in the management of colorectal cancer: comparison with CT.

Immunoscintigraphy performed after intravenous administration of indium-111-labeled CYT-103, an immunoconjugate of monoclonal antibody B72.3, was evaluated in patients with suspected primary or recurrent colorectal cancer at 25 centers in the United States. Gamma camera imaging, computed tomography (CT), and confirmatory surgical exploration were completed in 169 of 227 patients who received single infusions of In-111 CYT-103. Eight patients (3.5%) had reversible, nonserious adverse reactions, and 39% developed antimurine antibodies. Surgery revealed that 155 of 169 patients had colorectal carcinoma. In these 155 patients, immunoscintigraphy and CT demonstrated similar sensitivity (69% and 68%, respectively) and specificity (77%). However, immunoscintigraphy had greater sensitivity in detection of pelvic tumors (74% vs 57%, P = .035) and extrahepatic abdominal tumors (66% vs 34%, P less than .001); CT enabled detection of a greater proportion of liver metastases (84% vs 41%, P less than .001). These results indicate that In-111 CYT-103 can be administered safely and that immunoscintigraphy performed with this agent frequently enables identification of extrahepatic abdominal sites of disease not visualized with CT.

Adult↗