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Biomedical subjects

C J MacLean

Publications and source records attributed to C J MacLean.

At least 73 records · Page 4Linked to original sources
PubMed1988

Reference values for FEV1 in Japanese-American men from 45 to 68 years of age.

Pulmonary function is known to vary by racial group, yet no standards have been published for Asian-Americans. The Honolulu Heart Program, a prospective epidemiologic study of cardiovascular disease, provided an opportunity to examine pulmonary function, specifically, forced expiratory volume in one second (FEV1), in Japanese-American men 45 to 68 yr of age. Of a cohort of 6,346 men, 1,490 were identified as healthy asymptomatic nonsmokers. Prediction equations and reference values were derived from this subgroup. When the prediction equation was compared with those derived from Caucasian and black populations, mean predicted FEV1 for Japanese-Americans was intermediate to higher values for Caucasians and lower values for blacks. In addition to age and height, skinfolds, dynamometry, and biacromial diameter were found to be independent predictors of FEV1. In summary, standards derived from Japanese-American populations should be used when measuring pulmonary function in this group and additional physical measurements make a small contribution to the accuracy of prediction equations.

Aged↗
PubMed1988

Correlates of FEV1 and prevalence of pulmonary conditions in Japanese-American men.

Correlates of forced expiratory volume in one second (FEV1) and the prevalence of pulmonary disease and symptoms were examined in 6,346 Japanese-American men 45 to 68 yr of age. There was a significant inverse dose-response relationship between FEV1 and cigarette smoking measured as pack-years, number of cigarettes, or number of years smoked. Ex-smokers had FEV1 values that were intermediate to the higher values for nonsmokers and the lower values for current smokers. Among current smokers, inhaling and starting to smoke at a younger age were associated with lower values of FEV1, independent of pack-years. FEV1 was also correlated with a variety of other biologic and sociobehavioral variables, even after removing the effects of smoking. These variables included skinfold thickness, dynamometry, hematocrit, triglycerides, and systolic blood pressure. When compared with Caucasian populations, these Japanese-American men had low prevalence rates of airflow obstruction and pulmonary disease symptoms.

Aged↗
PubMed1988

Blood pressure, nephrosclerosis, and age autopsy findings from the Honolulu Heart Program.

The aspect of nephrosclerosis reflected by fibrous intimal thickening of small arteries (arteriosclerosis) was measured by a newly introduced morphometric procedure in 154 autopsies of Japanese-American men in Honolulu. These men were subjects of the Honolulu Heart Program and had previously been assessed for blood pressure and other clinical characteristics in a prospective study. In periodic acid-Schiff (PAS)-stained sections of renal cortex, measurements were made of interlobular artery diameters and intimal thicknesses. Vessels of outer diameter 80 to 130 microns and 160 to 300 microns were examined separately and are called the "remote" and "close" levels of the interlobular arteries, respectively, defined in relation to the heart. Nephrosclerosis thus quantified, together with age, could be used to predict the levels of blood pressure (BP) to be found in retrospective review of past records. The mathematical function obtained in a former study to make these predictions was found to predict the observed levels of blood pressure to an acceptable degree in the groupings that involved 92% of the subjects. Verification of that formerly obtained predictive function is now claimed. Correlation coefficients relating BP to close and remote measures were about of equal magnitude (r = 0.34 and 0.40, respectively). Subjects with cardiovascular-renal causes of death differed in both nephrosclerosis and blood pressure from subjects whose cause of death was unrelated to cardiovascular-renal diseases; the two factors taken together each contributed significantly to the cause of death difference. Correlations between nephrosclerosis and aortic atherosclerosis were stronger than could be explained solely by a linkage to observed values of blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1987

Predictors of atherosclerosis in the Honolulu Heart Program. I. Biologic, dietary, and lifestyle characteristics.

Of 8,006 men of Japanese ancestry living in Hawaii who were followed from 1966 to 1983 for incident cardiovascular disease, 1,381 died and 290 had a protocol autopsy which included determination of the extent of atherosclerosis in the coronary arteries and aorta. More than 50 biologic, lifestyle, and dietary characteristics, measured in 258 of the men who did not have existing evidence of definite coronary disease or stroke at the baseline examination, were examined for association with the measures of atherosclerosis using models which did and did not include adjustments for autopsy selection bias. Blood pressure and serum cholesterol were the strongest and most consistent predictors of atherosclerosis in both the coronary arteries and aortas. Cigarette smoking was also consistently associated with aortic atherosclerosis and inconsistently with coronary atherosclerosis. Several other variables often associated with clinical coronary artery disease in this cohort were not found to be independently associated with atherosclerosis. These included alcohol use, physical activity, serum glucose, triglyceride, and uric acid levels. None of more than 25 measures of dietary patterns and 24-hour dietary intake was associated with atherosclerosis in any statistical model. Examination of age-adjusted and age-specific levels of atherosclerosis over time from 1966 to 1983 showed a slight decrease in coronary atherosclerosis and a slight increase in aortic atherosclerosis; however, these trends were not significant. Both myocardial scars measured at autopsy and clinical evidence of myocardial infarction were significantly associated with the coronary atherosclerosis scores.

Aged↗
PubMed1987

Predictors of atherosclerosis in the Honolulu Heart Program. II. Adjustment for autopsy bias.

Although autopsy is considered the final word on many medical questions, there has long been concern over possible bias in inference about a living population from analysis of autopsy material. Focus of the present paper is on the relationship between results obtainable only at autopsy and risk factors recorded as part of a prospective study of the entire "target population." Since pathologies are sure to be overrepresented in an autopsy sample compared to the target population, the dependence of autopsy scores upon risk factors may be distorted in the autopsy sample. The present paper proposes a method of adjustment for this bias. When both autopsy sample and target population can be stratified by major disease categories, under certain assumptions of equal effect, adjustment similar to the direct method for age adjustment may be applied. If, in addition, dependence can be characterized accurately by linear regression of both autopsy score and disease category frequency onto risk factors, then a very convenient calculation produces adjusted regression coefficients. This "parametric" method usually provides the most convenient results, with the greatest statistical power.

Analysis of Variance↗
PubMed1986

Prognostic factors for loco/regional control and metastasis and the impact on survival.

For the identification of predictive factors for local (head and neck) control and metastases and impact on survival in squamous cell cancer of the head and neck, we have used data from over 2000 patients from the Patterns of Care Study (PCS) and the Radiation Therapy Oncology Group (RTOG) studies. Complete local response (C.R.) is significantly related to T stage, N stage, general performance status (Karnofsky), and site of primary tumor. There is a strong association between T and N stage. T1N0 tumors showed a C.R. of 99%, whereas, T1N3 had a C.R. of 57%. T4N0 showed a C.R. of 75%, but this went down to 31% in the T4N3 lesions. Glottic tumors showed a C.R. of 96% versus the other sites, which ranged from 81% for the nasopharynx to 59% for the hypopharynx. Patients with a performance status (KPS) of less than 90% showed a C.R. of 60% versus 88% for AKPS 90% or higher. Absence of local recurrence after C.R. is significantly related to T stage, N stage, and the site of primary tumor (glottis versus the rest). The appearance of distant metastases is significantly related only to N stage and primary site. This relationship persists in control of loco/regional tumors. In Stages III & IV in non-glottic head and neck cancer, metastases as the cause of death play an increasingly important role. This can be as high as 30%. The appearance of new malignant tumors and death unrelated to cancer, that is, death related to lifestyle, assumes an important role in patients with advanced head and neck cancer. The number of advanced glottic larynx was too small to examine this question. The use of a surgical procedure in carcinomas of the anterior tongue and floor of the mouth was associated with a smaller percentage of infield recurrences at 2 years, than when radiation therapy alone was used (27% versus 88% p less than .01). The same observation was noted at 3 years in the glottic and supraglottic Stage III & IV tumors (p less than .01).

Carcinoma, Squamous Cell↗
PubMed1986

Multipoint linkage analysis.

A formula is given for the advantage of n-point sampling, which approaches infinity with n. However, 2-point and 3-point analyses extract nearly all the information in such samples and at the same time communicate this information as lods and chi 2, which can be combined with other data by simple addition without reevaluation of the likelihood. When null interference is assumed, map distances and multiple recombination frequencies are inflated, and there is substantial loss of efficiency and of support for the correct order.

Animals↗
PubMed1985

The genetic susceptibility to insulin-dependent diabetes mellitus: combined segregation and linkage analysis.

We report a combined segregation and linkage analysis of a Danish sample of 216 insulin-dependent diabetes mellitus (IDDM) nuclear families: of these 216, twenty multiplex families were haplotyped regarding HLA-DR and -B markers. The analysis was conducted using the computer program COMBIN, which includes a modifier to absorb family resemblance that is additional to the effect of the major locus that is assumed linked to a marker locus, eg, within the HLA region. The initial analysis could clearly reject a dominant major locus but could not discriminate between other models with or without modifier. However, after adding supplementary information on population associations between HLA and IDDM together with the identity-by-descent (IBD) distribution to the analysis, a final model was identified. This invokes an additive major locus, linked to HLA with recombination not significantly different from 0, a disease gene frequency of 0.217, plus a dominant modifier. From this model it can be predicted that about 0.15% of the general population is at 100% risk of IDDM, about 5% is at intermediate risk (approximately 10%), while the remaining population has a risk of 0. The model predicts recurrence risks compatible with empirically estimated values. Particularly strong, positive haplotype associations were found for the DR3,B8, DR3,B18, and DR4,B15 haplotypes, but detailed analyses showed that neither these particular haplotypes nor the DR3 and DR4 haplotypes in general could entirely explain the HLA-associated susceptibility. The DR2 haplotypes showed a strong negative association. The results are discussed in the light of available data on the epidemiology of IDDM in order to provide a framework for further epidemiological studies.

Diabetes Mellitus, Type 1↗
PubMed1985

Efficiency of lod scores for representing multiple locus linkage data.

The problem of compact, fully efficient representation of multilocus data has not yet been solved. Lod scores can be used to map multilocus data, but because of certain statistical problems, this method loses some information. However, simulation studies show that for distances less than 10 or 20 cMo, where there is little danger of huge overestimates of distance, the lod score method yields estimators just as good as maximum likelihood (ML). Since short distances are the most important, the lod method is quite efficient. Its main drawback is misrepresentation of the likelihood under wrong gene orders. This problem can be ameliorated with a single multipoint calculation under each order. Thus, representation of multipoint data with lod scores can be very practical.

Biometry↗
PubMed1985

Estimation of myriad haplotype frequencies.

The present paper demonstrates algorithms for applying gene counting estimation of haplotype frequencies in very large genetic systems. A factor union representation of phenotypes is used which conveniently yields the sets of potential haplotypes and diplotypes for each phenotype. Methods for storing and rapidly retrieving the relevant haplotypes are given. An example with several hundred frequencies is given which required a few seconds computing time for each estimation iteration on a small computer. A computer program employing the methods described has been written in Fortran-77 and is available to any investigator on request.

Gene Frequency↗
PubMed1985

Construction of conditional lod tables from multiple-locus linkage data.

Although multipoint linkage data are becoming quite common, economical and efficient methods for presenting these data are not yet in use. Tables giving the full likelihood function would be very voluminous, whereas reduction to standard lods destroys part of the information. We suggest a special lod table representation which preserves nearly all the information about both gene order and genetic map distance at a great reduction in data presented. Conditional lods, coined "c-lods" to distinguish them clearly from ordinary lods, are calculated for distances between each adjacent pair of loci, with all distances among other loci in the system conditionally optimized. Thus, in an n-locus system, conditional lods are presented for the n - 1 adjacent pairs of loci only. The principal reason for reporting lod scores is the potential for combining data from separate studies to reach conclusive evidence for linkage and gene order. Because estimates of recombination are different in each set of data, the crux of the problem is to present scores that provide a close approximation to the true likelihood away from maximum likelihood (ML). The sum of conditional lods closely approximates the likelihood throughout the domain. Therefore, conditional lods contribute appropriately when mapping from several sources of data, so contradictory estimates can be reconciled efficiently.

Biometry↗
PubMed1984

Combined analysis of genetic segregation and linkage under an oligogenic model.

For traits with incomplete penetrance, simultaneous segregation analysis and linkage analysis may offer increased information. Since the numerical properties of the mixed model are a drawback in this more complicated analysis, a second locus is substituted for the polygenic component yielding a simpler and more tractable oligogenic model. While less realistic, the simpler model is not easily discriminated from the mixed model, particularly when used on affection data rather than quantitative traits. Calculations for combined linkage and segregation analysis are described for nuclear families with pointers to account for sampling scheme.

Computers↗
PubMed1984

The Patterns of Care Outcome Studies: results of the National practice in carcinoma of the larynx.

The Patterns of Care Study conducted a survey of patients with glottic and supraglottic carcinomas treated in 1973 and 1974. Patients for this study were randomly selected from all types of treatment facilities, including those with full and part-time therapists and large and small institutions. Detailed evaluation and treatment parameters were recorded for a total of 707 patients. Overall three-year recurrence free survival for glottic carcinoma was: Stage I, 90%; Stage II, 78%; Stage III, 65%; and Stage IV, 23%. For supraglottic carcinoma the rates are: Stage I 78%, Stage II, 60%, Stage III, 34% and Stage IV, 30%. The use of surgery in this study for advanced lesions varied among different departments. For advanced lesions, those treated with combined radiation and surgery had improved survival; this was also related to completeness of work-up and departmental equipment.

Carcinoma, Squamous Cell↗
PubMed1983

Patterns of care study: Hodgkin's disease relapse rates and adequacy of portals.

The Patterns of Care Study (PCS) has noted differences in stage adjusted relative relapse rates for Hodgkin's disease in four large facilities; the rates vary from 0% to 11% for infield or marginal recurrence (P = 0.003), and from 10% to 39% for any relapse (P = 0.0006) among these facilities. These differences in outcome were not attributable to variation in patient workup, treatment method, or radiation dose. A resurvey of 181 of these records of patients treated with radiation therapy for cure, in which portal films were available for review, indicates that treatment portal films did not encompass the disease adequately in 66 patients. When this occurred, there was a 50% overall relapse rate with 32% recurrence either infield or marginal. Chemotherapy tended to obscure the effect of inadequate technology, and when the 26 patients receiving chemotherapy as part of their initial treatment were excluded, inadequate margins were followed by even higher rates of relapse. For the subgroup of patients treated with radiation therapy alone, inadequate margins were associated with a 54% overall relapse rate, of which 33% were infield or marginal recurrence. When the portal films for patients treated with radiation therapy only were judged to be adequate, the total rate of any relapse was 14%, with 7% infield or marginal recurrence. PCS data indicate there is a critical need for accurate inclusion of Hodgkin's disease in the treatment portals; that marked facility differences exist in this technical process; and that skilled independent observers can reliably identify inaccurate technical performance.

Evaluation Studies as Topic↗