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Biomedical subjects

S B Green

Publications and source records attributed to S B Green.

At least 55 records · Page 3Linked to original sources
PubMed1987

Patient age, histologic features, and length of survival in patients with glioblastoma multiforme.

Histologic sections from 71 patients with glioblastoma multiforme were reviewed to identify histologic prognostic factors and to explain the significantly shorter survival in older patients. Slides were studied for 14 histologic variables from a group of 35 patients aged less 45 years and from 36 patients aged 65 years or more. The relation of these histologic factors to the length of survival and age group was then investigated. The results document the marked histologic and cytologic heterogeneity of the glioblastoma and reaffirm the importance of necrosis as a prognostic factor. The results further suggest that patients whose glioblastomas contained microcysts, pseudopalisading, cells with astrocytic differentiation, and large areas of better differentiated glioma, did better than those patients whose lesions were homogeneously composed of small cells or whose lesion had a small median nuclear size. The study reaffirmed the strong (P less than 0.0001) negative relationship between advancing age and duration of postoperative survival. The presence of necrosis, a smaller standard deviation of nuclear size, the extent of vascular proliferation, the absence of well differentiated neoplastic fibrillary astrocytes, and neoplasms composed homogeneously of small cells were related to patient age and offered a possible explanation for at least part of the observed age effect. However, the strong relation between age and survival remained significant when adjusted for other variables, and the effect of age must rest largely on factors other than those detected in this morphologic study.

Adult↗
PubMed1987

Dietary fat and breast cancer in the National Health and Nutrition Examination Survey I Epidemiologic Follow-up Study.

The relationship between dietary fat intake and breast cancer incidence was examined in the National Health and Nutrition Examination Survey I (NHANES I) Epidemiologic Follow-up Study cohort. This cohort is derived from adults (greater than or equal to 25 yr) examined in the NHANES I (1970-75) cross-sectional survey of the U.S. population and provides a mean follow-up time of 10 years. An analytic sample of 5,485 women, including 99 breast cancer cases (34 premenopausal and 65 postmenopausal at NHANES I baseline), was examined for associations with dietary intake of fat, percent energy from fat, total energy, saturated fat, polyunsaturated fat, monounsaturated fat, and cholesterol on the basis of a 24-hour recall administered at the baseline NHANES I examination. No significant differences in dietary fat intake between cases and noncases were evident when mean intakes for each group were compared. For total fat (g) and saturated fat (g), a significant inverse association was indicated in proportional hazards analyses. Adjustment of fat for total energy intake resulted in a smaller effect that was no longer statistically significant. Adjustment for accepted breast cancer risk factors did not change these findings. This prospective study of a sample from the U.S. population does not support the hypothesis that high dietary fat intake increases breast cancer risk. Indeed, some lower risk associated with high fat intake may be indicated, although this result may be influenced by methodologic problems with the dietary assessment.

Adult↗
PubMed1987

In vivo studies on cataracts using the Scheimpflug slit lamp camera.

We conducted reproducibility studies on an in vivo objective method of documenting cataracts: Scheimpflug photography using the Topcon SL 45 camera. Normal and cataractous lenses were photographed and the photographs digitized and analyzed using a Perkin Elmer microdensitometer attached to a PDP 11 and Vax 11/780 computer. Linear densitometry was performed through the center of the lens. We found very good reproducibility. The intraclass correlation for the mean densities in the nucleus was 0.95: that is, intra- and interobserver variability accounted for only 5% of the overall variability. For the anterior cortex, intraclass correlation was 0.88 and for posterior cortex it was 0.84. This method may be useful, within limits, in future clinical trials of anticataract medications.

Cataract↗
PubMed1985

Glioblastoma multiforme and anaplastic astrocytoma. Pathologic criteria and prognostic implications.

A total of 1440 malignant astrocytic gliomas from three Phase III trials of the National Brain Tumor Study Group were studied to document the clinical usefulness of subclassifying these lesions as either an anaplastic astrocytoma or a glioblastoma multiforme. As defined by a previous "blind" pathology review, the two groups of patients were compared as to mean age, mean duration of preoperative symptoms, and postrandomization survival. In addition, 10 histologic variables were studied in 150 patients with the anaplastic astrocytoma to establish internal correlations, and to relate specific histologic variables to patient age and postrandomization survival. There were highly significant differences in the age, duration of preoperative symptoms, and post randomization survival between the two groups. Internal correlations between histologic variables in the anaplastic astrocytoma disclosed statistically significant associations between the presence of lymphocytes and gemistocytic astrocytes. It is concluded that the subclassification of malignant gliomas into the anaplastic astrocytoma and the glioblastoma multiforme defines groups of patients that are significantly different in regard to age, duration of symptoms, and length of survival. The problems of tissue sampling are recognized, however, the assignment, by a blind pathology review, to two such different groups indicates that the classification has utility for large randomized clinical trials. The analysis of histologic variables in the anaplastic astrocytomas confirms previous suggestions that lymphocytes and gemistocytes frequently coexist in malignant gliomas, but in this study these inflammatory cells did not appear to influence survival. The study reemphasizes the association between advancing age and shorter survivals in patients with malignant gliomas.

Actuarial Analysis↗
PubMed1985

Estimating the population attributable risk for multiple risk factors using case-control data.

A straightforward and unified approach is presented for the calculation of the population attributable risk per cent (etiologic fraction) in the general multivariate setting, with emphasis on using data from case-control studies. The summary attributable risk for multiple factors can be estimated, with or without adjustment for other (confounding) risk factors. The relation of this approach to procedures in the literature is discussed. Given values of the relative risks for various combinations of factors, all that is required is the distribution of these factors among the cases only. The required information can often be estimated solely from case-control data, and in some situations relative risk estimates from one population can be applied to calculation of attributable risk for another population. The authors emphasize the benefits to be obtained from logistic regression models, so that risks need not be estimated separately in a large number of strata, some of which may contain inadequate numbers of individuals. This approach allows incorporation of important interactions between factors, but does not require that all possible interactions be included. The approach is illustrated with data on four risk factors from a pair-matched case-control study of participants in a multicenter breast cancer screening project.

Biopsy↗
PubMed1984

Prospective study of alcohol consumption and cancer.

The relation between alcohol consumption and the subsequent occurrence of the five most frequent cancers in Japanese men in Hawaii (cancer of the stomach, colon, rectum, lung, and prostate) was analyzed in a prospective study of 8006 subjects. Information on alcohol consumption was obtained through interviews in the mid-1960s, and the cohort has been followed since then. The analysis, which was adjusted for the effects of age and cigarette smoking, revealed a positive association between consumption of alcohol and rectal cancer, accounted for primarily by an increased risk in men whose usual monthly consumption of beer was 500 oz (15 liters) or more (relative risk, 3.05; P less than 0.01, as compared with those who did not drink beer). A significant positive relation between alcohol consumption and lung-cancer incidence was also found, accounted for primarily by an increased risk among subjects who consumed larger amounts of wine or whiskey, as compared with the risks among nonconsumers of these beverages (relative risk, 2.19, [P = 0.03] and 2.62 [P less than 0.01], respectively). No significant relation between alcohol consumption and the incidence of the other three cancers was found.

Aged↗
PubMed1984

Clinical staging for cutaneous T-cell lymphoma.

The Mycosis Fungoides Cooperative Group has been following patients with cutaneous T-cell lymphoma, including mycosis fungoides and the Sézary syndrome variant. Previous analyses identified the extent of skin involvement and the number of sites of clinically enlarged lymph nodes as important prognostic variables. These two variables were used to classify 340 patients into four clinical stages. Repeat analysis based on additional followup data shows the usefulness of this clinical staging system for identifying patients with differing survival experience. An alternative grouping suggested by fitting a survival model to the data also has been studied. Staging systems based only on skin involvement and lymph nodes are recommended for general use because the information needed is readily available, requiring only physical examination.

Humans↗
PubMed1984

A comparison of reflected versus test-based confidence intervals for the median survival time, based on censored data.

The small-sample performance of some recently proposed nonparametric methods of constructing confidence intervals for the median survival time, based on randomly right-censored data, is compared with that of two new methods. Most of these methods are equivalent for large samples. All proposed intervals are either 'test-based' or 'reflected' intervals, in the sense defined in the paper. Coverage probabilities for the interval estimates were obtained by exact calculation for uncensored data, and by stimulation for three life distributions and four censoring patterns. In the range of situations studied, 'test-based' methods often have less than nominal coverage, while the coverage of the new 'reflected' confidence intervals is closer to nominal (although somewhat conservative), and these intervals are easy to compute.

Biometry↗
PubMed1983

Autologous serologic responses in glioma patients. Correlation with tumor grade and survival.

The serologic responses of 42 patients with gliomas have been evaluated in a quantitative microcytotoxicity assay utilizing autologous cultured glioma cells. Forty-five percent of patients had detectable cytotoxic antibody apparently directed to their own cultured cells. When tumor grade was correlated with immune response, 15/20 patients with Grade I, II and III astrocytomas had antigens detectable in autologous sera whereas only 5/22 patients with Grade IV astrocytomas had such responses. None of the autologous fibroblasts from the 15 patients with paired gliomas and fibroblast lines had membrane antigens detectable using autologous sera and fibroblast absorption did not reduce antiglioma activity. Thus, the cytotoxicity observed in this assay appears to be restricted to tumor cells, suggesting reactivity against tumor-associated antigen. In addition, it appears that these immune responses are highly correlated with survival in primary malignant brain tumor patients.

Antibodies, Neoplasm↗
PubMed1983

Diagnostic accuracy of actuarial and one-point MMPI code systems with college students.

Assessed the applicability of standard clinical interpretations of the MMPI within a college counseling center. The relative classification rates and diagnostic accuracy of four actuarial and two one-point code systems for the MMPI were evaluated. Two hundred and five female and 207 male college students were administered MMPIs. In addition, independent diagnoses were obtained on each student. Diagnoses were made on the basis of each of the code type systems. The results indicated that (a) only the one-point code systems classified a large percentage of students who were diagnosed as neurotic, psychotic, or behavior disorder; (b) the accuracy of differential diagnosis among these psychiatric categories was at a satisfactory level for both male and female students with only the Gynther, Altman, and Sletten (1973a) and one-point code systems; and (c) the Gilberstadt and Duker (1965) and one-point code systems classified an excessively large percentage of students with minor adjustment problems as being neurotic, psychotic, or behavior disorder.

Adjustment Disorders↗
PubMed1983

Comparisons of carmustine, procarbazine, and high-dose methylprednisolone as additions to surgery and radiotherapy for the treatment of malignant glioma.

Within 3 weeks of definitive surgery, 609 patients with histologically demonstrated, supratentorial malignant glioma were randomized to receive, in addition to 6000 rads of radiotherapy, one of four treatment regimens: carmustine (BCNU), high-dose methylprednisolone, procarbazine, or BCNU plus high-dose methylprednisolone. We analyzed the data for the total randomized population and for the 527 patients (87% with glioblastoma multiforme) in whom the initial protocol specifications were met (the valid study group). Significantly longer survival was experienced by patients receiving procarbazine or BCNU alone compared to those receiving only high-dose methylprednisolone. No other pairwise comparisons demonstrated differences significant at the 0.05 level. However, the combination of BCNU plus high-dose methylprednisolone tended to be less effective than BCNU alone in patients with poor prognosis. This study indicates that BCNU and procarbazine are moderately useful agents in conjunction with radiotherapy for patients with malignant glioma. In addition, future protocols may allow use of corticosteroids in conventional dosages for treating cerebral edema and controlling symptoms; conclusions based on survival as the endpoint are unlikely to be affected by administering steroids at somewhat greater than the usual dose. More effective regimens for the treatment of malignant glioma should be sought.

Adolescent↗
PubMed1983

Clinical predictivity of transplantable tumor systems in the selection of new drugs for solid tumors: rationale for a three-stage strategy.

The purpose of this work is to analyze the strategy used for the discovery of potentially clinically effective drugs by means of transplantable tumor systems in mice. With the present strategy used by the National Cancer Institute and the European Organization for Research on Treatment of Cancer, most new compounds are initially tested in the P388 leukemia model. Drugs showing activity in this prescreen are subsequently evaluated in a panel of eight screens (B16, CD8, Co38, L1210, LL, CX-1, LX-1, and MX-1). Positivity in any one of these screens qualifies a new drug for further preclinical studies leading to phase I-II clinical trial. Our analyses of the experimental screening data for 1949 compounds, and the comparison of results in humans and mice for 69 drugs that have been clinically evaluated against solid tumors, have indicated that the correlation of screening and clinical results is low and that a modified approach using four systems (P388, B16, L1210, and MX-1) would have been sufficient to uncover most of the drugs presently shown to be clinically active. In order to take advantage also of the information provided by other screens of the panel, a three-stage strategy can be used. In the first stage, compounds would be tested in the P388 prescreen, with a slightly higher level of response being required (T/C% greater than or equal to 125 instead of 120). In the second stage, prescreen-positive drugs would be tested in the B16, L1210, and MX-1 systems. Drugs positive in any one of these screens may then be tested in Co38, LL, and CX-1 to determine priorities for clinical study. For new chemical structures of particular promise, this third stage could be dropped. LX-1 and CD8 are not useful in this context. Such a strategy would be much more economical and faster than the automatic use of nine systems, and the resultant savings should permit the discovery of an increased number of potentially active compounds.

Animals↗
PubMed1982

Patient heterogeneity and the need for randomized clinical trials.

The hierarchy of strength of evidence concerning treatment efficacy ranges from individual anecdotal case reports, through studies with nonrandomized controls, to randomized clinical trials. The importance of randomized trials is their ability to convince the medical community. With randomization, bias (whether conscious or unconscious) is avoided, prognostic factors (both known and unknown) tend to be balanced across treatment groups, the validity of statistical tests of significance is guaranteed, and problems with time trends are avoided. A study of thyroid carcinoma demonstrates the importance of prognostic factors, and indicates how they can be identified using a Weibull model and used to form a prognostic index. A study of prostatic cancer illustrates how covariate information can be used to select optimal treatment for different patient subgroups in situations where there is no single best overall treatment. The key to successful clinical trials is a renewed effort in developing and selecting the treatments to be studied.

Antineoplastic Agents↗
PubMed1982

Additional power computations for designing comparative Poisson trials.

Published power computations for designing comparative Poisson trials are extended to the case of unequal populations sizes. The goal is to determine the required duration of a study for testing the one-sided alternative that the incidence rate of a rare disease in one population exceeds that in another population, based on an exact test conditional on the total number of events observed. Tables are provided for two designs: observing until a predetermined number of events have been observed, or observing for a predetermined length of time. The results may also be used to determine sample sizes for comparative binomial trials with very small binomial parameters when the numbers of patients in the two groups are not necessarily equal.

Epidemiologic Methods↗