Search PubMed⌕ Search

Biomedical subjects

C G Chute

Publications and source records attributed to C G Chute.

At least 73 records · Page 4Linked to original sources
PubMed1993

Natural history of prostatism: urinary flow rates in a community-based study.

Urinary flow rates were measured in a randomly selected community sample of more than 2,000 men 40 to 79 years old with no history of prostate surgery, prostate cancer or certain other diseases known to interfere with normal voiding. Peak urinary flow rates decreased from a median of 20.3 ml. per second in men 40 to 44 years old to 11.5 ml. per second for men 75 to 79 years old, while voided volumes decreased from a median of 355.5 to 222.5 ml. for the same age ranges. Peak flow rates of less than 10 ml. per second were found in 6% of the men aged 40 to 44 years, increasing to 35% among men aged 75 to 79 years. Urological standards for peak urinary flow rate should be based on community data, and should account for age and voided volume. Our study may serve as the starting point for the development of community-based flow rate normal ranges. Nomograms are given to permit estimating flow rate percentiles as a function of age and voided volume.

Adult↗
PubMed1993

Similar levels of urological symptoms have similar impact on Scottish and American men--although Scots report less symptoms.

Urinary symptoms and the extent to which they interfere with living activities were compared in 2 community-based investigations that enrolled men 40 to 79 years old who were randomly sampled from Olmsted County, Minnesota (2,119) and the Forth Valley of Scotland (1,385). Both investigations included symptom questions with wording that is nearly identical to that of the American Urological Association (AUA) symptom index. Following AUA scoring conventions we grouped scores into mild (AUA score 0 to 7), moderate (score 8 to 19) and severe (score 20+) categories. Minnesota men had symptoms that were more frequent, more bothersome and caused greater interference with living activities than did Scottish men of comparable age (p < 0.0002). However, within each symptom score category, the extent to which symptoms interfered with living activities was essentially the same in both populations. Although there appear to be important differences in urinary symptom prevalence between Scotland and Minnesota, the AUA symptom index provides a consistent measure of the extent to which urinary symptoms interfere with living activities in both populations. These findings support use of the AUA symptom index in the diagnostic evaluation of men with benign prostatic hyperplasia.

Adult↗
PubMed1993

Endemic giardiasis in New Hampshire: a case-control study of environmental risks.

Giardiasis is the most frequently reported diarrheal disease in northern New England. A case-control study of endemic giardiasis and environmental risk factors among residents of New Hampshire involved 273 cases from the state's 1984 disease registry and 375 controls. Giardiasis was associated with a shallow dug well as a residential water source (odds ratio [OR] = 2.4; 95% confidence interval [CI], 1.3-47.0), a recent history of drinking untreated surface water (OR = 3.4; CI, 2.1-5.5), a history of swimming in a lake or pond (OR = 4.6; CI, 2.4-86.0) or swimming in any natural body of fresh water (OR = 4.0; CI, 2.3-70.0), contact with a person thought to have giardiasis (OR = 2.3; CI, 1.4-36.0), and recent contact with a child in day care (OR = 1.5; CI, 1.0-2.1). Multivariate modeling supported these associations. Shallow wells, relatively common in New Hampshire, have not previously been established as important sources of giardiasis.

Adolescent↗
PubMed1993

The Universal Patient Identifier: a discussion and proposal.

The broad-based need for a standard, robust patient identifier is reviewed. Advantages and difficulties of the Social Security Number are considered. An alternative number, composed of birthdate, location, and check digits, is proposed. Logistic extensions of the geographically based schema are made for provider and facility identification. Several variations of representation are described in base 34, which make the composite number short, easily derived and decoded, and robust.

Humans↗
PubMed1993

Words or concepts: the features of indexing units and their optimal use in information retrieval.

Words or Concepts, which are a better choice for indexing the contents of documents? The answer depends on what method is used for retrieval. This paper studies the effects of using canonical concepts versus document words in different retrieval systems with a testing collection of MEDLINE documents. In our tests, for a retrieval system which does not use any human knowledge, using words yielded better retrieval results, while using concepts suffered from a vocabulary difference between canonical expressions of concepts and non-canonical words in queries or documents. For a system which depends on the UMLS synonym set for a mapping from queries or documents to canonical concepts, the retrieval results were slightly better than the case of not using the synonyms, but still worse than the systems using words. For the systems which automatically "learn" empirical connections between words and concepts from examples in the testing collection, the vocabulary problem was effectively solved, and the results of using concepts were competitive or better, compared to those using words.

Abstracting and Indexing↗
PubMed1992

Validation of a new quality of life questionnaire for benign prostatic hyperplasia.

In planning a longitudinal study to characterize the natural history of benign prostatic hyperplasia (BPH), we validated a new disease-specific quality of life questionnaire in a pilot study. We studied 110 men in Rochester, Minnesota who spanned the severity of BPH, from men with no known BPH to men who underwent surgery for this condition. Baseline data were obtained on all men, and the 30 who underwent prostatectomy were re-interviewed to test responsiveness. Reproducibility was examined on the pre-post responses (10 weeks apart) of the 37 men with BPH who did not undergo prostatectomy. Six of twelve question domains were retained in the final questionnaire on the basis of their responsiveness to change, reproducibility, internal consistency, and validity. These were: urinary symptoms, degree of bother due to urinary symptoms, BPH-specific interference with activities, general psychological well-being, worries and concerns, and sexual satisfaction. Most of the more generic measures were deleted.

Adult↗
PubMed1992

Development of a clinical data architecture.

This paper presents a methodology for developing a data architecture for clinical medicine. The methodology uses an object-oriented analysis approach that takes advantage of the domain expertise of practicing physicians. The resulting high-level data model combines a structured, event-based model of clinical information with the process-oriented structures usually associated with problem lists and practice protocols.

Computer Systems↗
PubMed1992

An application of least squares fit mapping to clinical classification.

This paper describes a unique approach, "Least Square Fit Mapping," to clinical data classification. We use large collections of human-assigned text-to-category matches as training sets to compute the correlations between physicians' terms and canonical concepts. A Linear Least Squares Fit (LLSF) technique is employed to obtain a mapping function which optimally fits the known matches given in a training set and probabilistically captures the unknown matches for arbitrary texts. We tested our method with 16,032 texts from the Mayo Clinic, and judged the results using human-assigned answers. In a test for comparison, the LLSF mapping achieved a precision rate of 89% at 100% recall, outperforming alternative approaches including string matching (36% precision), string matching enhanced by morphological parsing (51% precision), and statistical weighting (61% precision).

Information Storage and Retrieval↗
PubMed1992

An evaluation of concept based latent semantic indexing for clinical information retrieval.

Latent Semantic Indexing (LSI) of surgical case report text using ICD-9-CM procedure codes and index terms was evaluated. The precision-recall performance of this two-step matrix retrieval process was compared with the SMART Document retrieval system, surface word matching, and humanly assigned procedure codes. Human coding performed best, two-step LSI did less well than surface matching or SMART. This evaluation suggests that concept-based LSI may be compromised by its two-stage nature and its dependence upon a robust term database linked to main concepts. However, the potential elegance of partial- credit concept matching merits the continued evaluation of LSI for clinical case retrieval.

Abstracting and Indexing↗
PubMed1991

The subsequent risk of internal cancer with Bowen's disease. A population-based study.

OBJECTIVE: To address the subsequent risk of internal cancer in a population-based cohort of patients with Bowen's disease. DESIGN: Incident cases of skin cancers other than malignant melanoma occurring in a defined population were classified as basal cell carcinoma, squamous cell carcinoma, or Bowen's disease. Through medical records, all patients were followed up for the development of subsequent internal cancer until they died, moved from Rochester, Minn, or January 1, 1986, whichever came first. Incidence rates of skin cancer and subsequent cancer were computed; the subsequent rate of internal cancer was compared with that prevailing in the community. PATIENTS: Enrolled were all permanent residents in the population base of Rochester, Minn, who developed basal cell carcinoma (n = 657), squamous cell carcinoma (n = 169), or Bowen's disease (n = 71) on the basis of pathologic examination and clinical presentation from 1976 through 1984. MAIN OUTCOME MEASURE: The relative risk of subsequent internal cancer among patients with Bowen's disease compared with that of the population base from which they arose was 1.1 (95% confidence limits, 0.5, 1.6). RESULTS: Annual incidence rates, adjusted to the 1980 US white population, were 14.9 per 100,000 for Bowen's disease, 38.8 for squamous cell carcinoma, and 146 for basal cell carcinoma. The estimated relative risk for subsequent cancer was 0.9 (95% confidence limits, 0.5, 1.6) among patients with squamous cell carcinoma and 1.0 (95% confidence limits, 0.7, 1.3) for patients with basal cell carcinoma. These risks were not significantly different for various durations of follow-up or for sun-exposed vs sun-protected sites. CONCLUSIONS: We find no evidence in these population-based cohort data of and increased risk of subsequent internal cancer associated with Bowen's disease or other forms of nonmelanomatous skin cancer.

Adult↗
PubMed1991

A prospective study of body mass, height, and smoking on the risk of colorectal cancer in women.

Female registered nurses in the United States who responded to a questionnaire in 1976 that inquired about height, weight, and smoking history were followed for the development of colon or rectal cancers through May of 1984. Among the 118,404 respondents free of cancer in 1976, 191 colon cancers and 49 rectal cancers were observed during 916,170 person-years of follow-up. After omitting cases diagnosed within two years of weight report, we found little overall relation of body mass (Quetelet's) index to colon cancer risk; however there was a suggestion of elevated risk for the heaviest category of body mass index (greater than or equal to 29 kg/m2, relative risk (RR) = 1.5; 95 percent confidence interval = 0.8 - 2.7) relative to the lowest category (less than 21 kg/m2). Self-reported body mass index from adolescence had a slightly more pronounced, although not significant, association with risk of colon cancer. Increasing height was significantly associated with colon cancer (RR = 1.6, 95 percent confidence interval = 1.1 - 2.5 for the tallest category [greater than or equal to 168 cm] versus the shortest (less than 160 cm], trend, P = 0.04). Measures of current or past smoking failed to demonstrate any consistent relationship with colon cancer.

Adult↗
PubMed1991

Urinary symptom and quality of life questions indicative of obstructive benign prostatic hyperplasia. Results of a pilot study.

In a pilot study of a urinary symptom and health-related quality-of-life questionnaire for benign prostatic hyperplasia (BPH), responses from 64 Mayo Clinic patients with cystoscopic evidence of obstructive BPH were compared with those of 14 men with no cystoscopic evidence of BPH and a community sample of 64 comparably aged men with no medical history of prostate enlargement. Questions which best discriminated between the groups were those dealing with urinary symptom frequency, bother due to urinary symptoms, and worry and concern about urinary problems. The results suggest that urinary-symptom-bother and worry due to urinary symptoms may be important additions to the more usual questions asked about urinary frequency in the identification of men with BPH. These findings are preliminary, however, and will be verified in an ongoing natural history study of BPH.

Humans↗
PubMed1991

Incidence and outcome of surgery for benign prostatic hyperplasia among residents of Rochester, Minnesota: 1980-87. A population-based study.

The incidence and outcome of surgery for benign prostatic hyperplasia (BPH) was studied in Rochester, Minnesota, during the period 1980-1987. Three hundred thirty Rochester men without a diagnosis of prostate or bladder cancer underwent prostatectomy for BPH for the first time. Mean and median ages were both seventy (range: 46-95). The incidence of initial prostatectomy for BPH among men forty-five years of age and older age-adjusted to the 1980 U.S. white male population was 642 cases per 100,000 persons per year (py). Among the 330 men undergoing initial prostatectomy for BPH, 14 (4.2%) had serious intraoperative complications, 32 (9.7%) were rehospitalized for urologic complications within thirty days of surgery, and 13 (3.9%) had other serious complications within thirty days after surgery, including 1 death (surgical mortality 0.3%). Forty-five patients (14%) required blood transfusions within thirty days of surgery. The likelihood of reoperation within six years of the initial surgery was 15.1 percent (95% CI 9.7, 20.6). Short- and long-term postoperative mortality was not statistically significantly different than expected based on age- and sex-specific mortality statistics for Rochester, Minnesota.

Aged↗
PubMed1991

A prospective study of reproductive history and exogenous estrogens on the risk of colorectal cancer in women.

Among 118,404 female registered nurses who responded to a mailed questionnaire and had no history of cancer in 1976, 191 colon cancers and 49 rectal cancers were diagnosed during 8 years of follow-up. We observed no material association between parity and colon cancer risk; women who bore four or more children had a risk similar to that of nulliparous women (age-adjusted RR = 1.1, 95% confidence limits (CL): 0.6, 1.9). No consistent patterns of colorectal cancer risk were associated with age at menarche or at first birth. Current or past use of oral contraceptives did not appreciably alter the risk of colorectal cancer; past use of postmenopausal estrogens was associated with a reduced risk of colorectal cancer (RR = 0.5, 95% CL: 0.3, 1.0). These and other data do not support any substantial effect of reproductive history or oral contraceptive use on the risk of large bowel cancer; however, the possible protective role of postmenopausal estrogen therapy merits further investigation.

Adult↗
PubMed1991

Benign prostatic hyperplasia: a population-based study.

To evaluate the incidence and outcome of initial surgery for benign prostatic hyperplasia (BPH) and to clarify the natural occurrence and progression of such urologic diseases, two studies have been conducted in a free-living population in Rochester, MN. The first followed 330 men who had not been diagnosed with prostate or bladder cancer at the time of prostatectomy. All surgery subjects were area residents and between 46 and 95 years of age (mean age 70 years). Among the operated subjects, 14 (4.2%) had serious intraoperative complications, 32 (9.7%) were rehospitalized for urologic complications within 30 days after surgery, and 13 (3.9%) experienced other serious complications in that same time period. Blood transfusions within 30 days of surgery were necessary in 45 patients (14%). The risk of reoperation within 6 years of the initial surgery was calculated at 15.1% (95% CI: 9.7, 20.6). On the basis of age- and sex-specific mortality statistics for Rochester, short- and long-term postoperative mortality was not statistically significantly different from that expected. Results of the second study are not yet available. This population-based evaluation of the natural history of urologic disease is expected to clarify the relative utility of various treatment options and provide a useful perspective on the management of BPH.

Aged↗
PubMed1991

Latent Semantic Indexing of medical diagnoses using UMLS semantic structures.

The relational files within the UMLS Metathesaurus contain rich semantic associations to main concepts. We invoked the technique of Latent Semantic Indexing to generate information matrices based on these relationships and created "semantic vectors" using singular value decomposition. Evaluations were made on the complete set and subsets of Metathesaurus main concepts with the semantic type "Disease or Syndrome." Real number matrices were created with main concepts, lexical variants, synonyms, and associated expressions. Ancestors, children, siblings, and related terms were added to alternative matrices, preserving the hierarchical direction of the relation as the imaginary component of a complex number. Preliminary evaluation suggests that this technique is robust. A major advantage is the exploitation of semantic features which derive from a statistical decomposition of UMLS structures, possibly reducing dependence on the tedious construction of semantic frames by humans.

Abstracting and Indexing↗
PubMed1991

A schematic analysis of the Unified Medical Language System.

The UMLS is a complex collection of medical terms and relationships derived from standard classifications. Appreciating the scope and layout of these relations from text descriptions of relational schema is difficult. The graphical technique of Logical Data Structure (LDS) representation was employed to illustrate the UMLS schema as a data abstraction, affording additional insights that might otherwise escape notice. An LDS representation of the Metathesaurus offers the following advantages: 1) the separation of a viewpoint from physical data structures enables a global outline of the contents; 2) the graphical map makes the interrelation of data visible; and 3) the logical entities explicitly reflect the decision-making which was implicit or ambiguous in the relational scheme.

Models, Theoretical↗