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Biomedical subjects

R C Grimson

Publications and source records attributed to R C Grimson.

29 records · Page 2Linked to original sources
PubMed1981

A statistical test for classification, with applications to the characterization of pathogens according to antibiotic susceptibility patterns.

If n different analytical procedures are applied to a culture of a pathogen, then that pathogen is characterized by an ordered sequence or vector of length n. A group of such sequences (or 'susceptibility patterns' as they are called in this context) can be generated by applying this process to cultures taken from infected individuals in an epidemic. This paper introduced statistical tests that can be used to determine whether a pattern obtained from the culture of a single case differs from those patterns obtained from cultures of a group of infected individuals. The methods are applied to come nosocomial epidemics. These taxonomic techniques extend beyond the present application to other classification problems in the biological and medical sciences.

Anti-Bacterial Agents↗
PubMed1980

Predominance of early endometrial cancers after long-term estrogen use.

Clinical stage and pathological characteristics of endometrial cancer cases were related to several aspects of estrogen prescribing. In comparing 256 cases with 321 community control subjects, estrogen use of less than 3 1/2 years' duration did not increase the risk of endometrial cancer for any stage, grade, histological type, or extent of ivasion. With long-term estrogen use (3 1/2 years or more), relative risks were significantly increased (5.2 to 7.6) for the early cancers--those clinically stage IA, histologically grade 1, and invading the endometrium only. These increases were seen with both high-dose (greater than 0.625 mg) and low-dose (less than or equal to 0.625 mg) preparations. Risks were only minimally increased for the more advanced cancers. However, long-duration estrogen use did produce an increased risk of advanced cancer when administration was continuous rather than cyclic.

Adenocarcinoma↗
PubMed1980

"Alternative" controls in a case-control study of endometrial cancer and exogenous estrogen.

To address the issue of detection bias among endometrial cancer cases and controls, women admitted to the North Carolina Memorial Hospital for dilatation and curettage (D&C) during 1970-1976 were selected as one of three control groups in a study of endometrial cancer and exogenous estrogen. Study subjects included 256 cases, 316 D&C controls, 224 gynecology controls and 321 community controls. The D&C controls had a higher frequency of estrogen use than either of the other control groups or the cases. These differences existed for both blacks and whites. When white cases were compared to either gynecology or community controls, relative risks were increased for long duration estrogen use and for recent use prior to diagnosis. With D&C controls, relative risks were not significantly different from unity irrespective of duration or recency of estrogen use. Exclusion of hyperplasias from the D&C controls had no substantive effect of these results. Bleeding was a presenting complaint for 92% of cases, 82% of D&C controls and 22% of gynecology controls. Both among cases and gynecology controls, there was no statistically significant association between bleeding and estrogen use, whereas this association was evident among D&C controls, and specifically among those who did not have pathologic evidence of endometrial hyperplasia. These data support the presence of detection bias among D&C controls but they do not provide evidence of this bias among endometrial cancer cases.

Aged↗
PubMed1980

Aqueous humor outflow in beagles with inherited glaucoma: constant pressure perfusion.

Determination of facility of aqueous humor outflow (C), using constant pressure perfusion, was performed in vivo in normal dogs and in Beagles with inherited glaucoma at different stages of the disease process. Measurements were taken at 10 mm of Hg increments of intraocular pressure (IOP) from 10 to 50 mm of Hg IOP in the controls and to higher levels of IOP, as needed, to obtain 3 consecutive intervals in which perfusion was required in glaucomatous animals. In normal dogs, C increased slightly as IOP increased to a maximum of 0.22 at 50 mm of Hg. In glaucomatous dogs, C was significantly (P = 0.001) reduced compared with the value in the controls, with a maximum value of 0.09 at 50 mm of Hg.

Animals↗
PubMedDate not supplied

Disease clusters in structured environments.

This paper discusses the distributions of several cluster statistics and illustrates their utility in the analysis of disease incidence or prevalence data arising in organized or structured environments. Such environments involve primary inhabitant locations in office buildings, manufacturing plants, apartment complexes and communities of homes, for example. The methods, which include some generalizations of some existing methods as well as some new ones, will be used to test for household clustering of Trypanosoma cruzi seropositivity data.

Adolescent↗
PubMedDate not supplied

A statistical test for contact among individuals in an epidemic and a pattern among cases of acquired immune deficiency syndrome.

In investigating an epidemic or outbreak of a disease in which patient contact (appropriately defined) is hypothesized to be a factor, investigators may ask patients to provide names of people with whom they have had contact. This paper provides statistical methods for assessing whether or not the number of named contacts who are themselves cases is significantly large. Survey data on the epidemiology of acquired immune deficiency syndrome illustrate the methods.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Withdrawal of antihypertensive medications.

BACKGROUND: Pharmacologic treatment of hypertension reduces risks of stroke, congestive heart failure, renal failure, and mortality, but whether medications, once begun, need to be continued for life is uncertain. METHODS: Several search strategies on MEDLINE using key words "medication," "withdrawal," "discontinuance," and "therapy" in several combinations, nested within "hypertension," were not productive. Accordingly, articles known to the authors and citations within them were reviewed. A survey of a random sample of members of the New York Academy of Family Practice was conducted to ascertain current practice of practicing physicians. RESULTS: Eighteen studies of antihypertensive medication withdrawal were located and all were reviewed. In 12 trials average success rates of 40.3 percent after 1 year of follow-up and 27.7 percent after 2 years were achieved. In six studies limited to elderly patients, an average success rate of 26.2 percent was obtained for periods of 2 or more years. The trials, however, were heterogeneous in design, patient selection criteria, and follow-up. The survey of family physicians indicated that 79.1 percent attempt withdrawal of antihypertensive medications in hypertensive patients whose blood pressure is controlled and who are without symptoms from medication. CONCLUSIONS: We conclude that successful withdrawal of antihypertensive medications can have substantial benefits with few or no adverse consequences and might be successful in about one third of patients. Additional research is required to substantiate rates of successful medication withdrawal, to define the best method of withdrawing medications, and to delineate characteristics of patients in whom withdrawal is most likely to succeed.

Adult↗