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T Rice

Publications and source records attributed to T Rice.

At least 19 recordsLinked to original sources
PubMed1992

Commingling and complex segregation analysis of fasting plasma glucose in the Lipid Research Clinics family study.

Commingling and segregation patterns of fasting plasma glucose (GL) were examined in family data from 5 clinics (Cincinnati, Stanford, Iowa, Minnesota, and Oklahoma) of the Lipid Research Clinics (LRC) family study. In addition to the primary question of whether there was a major gene for GL, a secondary purpose was to investigate the possibility of genetic heterogeneity among the 5 clinics. No statistical support was found for heterogeneity among clinics, either in the commingling of distributions or in the segregation patterns. For the combined clinics sample, both a major effect and a multifactorial component were significant. However, the major effect (accounting for 73% of the variance) was not found to be consistent with a major gene, as the hypothesis of Mendelian transmission was rejected. The most parsimonious model involved equal transmission probabilities, which suggests that the major effect is not transmitted from parents to offspring. Possible sources of this major non-Mendelian effect were explored. The multifactorial component accounted for 10% of the variance in GL levels, and no generational differences were noted. Although our study was unable to provide evidence in favor of a major gene effect, it should be noted that a major gene cannot be firmly refuted. For example, a variety of interactions, such as genotype-dependent age effects, could have masked the transmission probabilities.

Adolescent↗
PubMed1992

Will Medicare beneficiaries switch physicians? A test of economic competition.

We assess the potential of increased economic competition by examining whether Medicare beneficiaries are willing to switch to physicians who agree to accept all services on assignment. Data come from a survey of Medicare beneficiaries conducted in November 1988. Our principal finding is that beneficiaries are not sensitive to price when making decisions about whether or not to switch physicians. Less than one-half of 1 percent of the sample had switched physicians for economic reasons in the year prior to the survey. Furthermore, willingness to switch was not correlated with ability to pay. We conclude that policies aimed at altering consumer demand may not be the most effective way to control Medicare costs.

Aged↗
PubMed1992

Commingling analysis of regional fat distribution measures: the Québec family study.

Regional fat distribution is related to higher risk of diabetes and cardiovascular morbidity and mortality, independent of excess body mass for height. In particular, the male (android) pattern of fat deposition, which is characterized by greater truncal and abdominal fat stores relative to extremity fat levels, is associated with a higher propensity to metabolic complications. Motivated by these considerations, we have initiated a systematic investigation of several measures of regional fat distribution aimed at the detection of possible single gene effects. In this paper, we assess the evidence for commingling in the distributions of these variables in a large French-Canadian study. Two measures approximating the size of subcutaneous fat stores relative to total body fat were considered: the sum of six skinfolds (SF6 = abdominal + supra-iliac + subscapular + calf + tricep + bicep), and the sum of three trunk skinfolds (TSF3 = abdominal + supra-iliac + subscapular). In addition, two measures assessing the distributional pattern of subcutaneous fat were considered: the ratio of TSF3 to the sum of the three extremity skinfolds (TER), and a relative fat pattern index [RFPI = subscapular/(subscapular + supra-iliac)]. All four measures were assessed both prior to and after adjusting for total fat mass, which was measured using underwater weighing. Significant distributional heterogeneity was observed for some of these measures, either between generations and/or between the sexes. In general, however, fat mass adjustment tended to eliminate the heterogeneity; the exception was for RFPI, for which sex differences were noted both prior to and after the adjustment. The finding of commingling of distributions for almost all phenotypes is consistent with (but not evidence for) major gene effects. However, for some of the measures the effect of a putative major locus genotype may be mediated by covariates such as age and/or sex.

Adipose Tissue↗
PubMed1992

Familial resemblance of blood pressure with residual household environmental effects in consanguineous and nonconsanguineous families from Andhra Pradesh, India.

Familial aggregation of blood pressure (BP), both systolic (SBP) and diastolic (DBP), was examined in consanguineous and nonconsanguineous families from southern India. Path analysis of BP suggests inbreeding effects, with the genetic variance for SBP being lower in the sample that included inbred families. Specifically, genetic heritability for SBP was 38% in the nonconsanguineous sample but only 23% in the combined sample. Genetic heritability for DBP (30%) did not vary by sample, nor were sample differences in cultural heritability detected for either SBP (over 35%) or DBP (about 18%). These findings are remarkably similar to those in a French-Canadian population of Quebec; both reports found a considerably larger effect of the home environment on BP than previous studies.

Blood Pressure↗
PubMed1992

Including an all-payer reimbursement system in a universal health insurance program.

This article examines the feasibility of including an all-payer reimbursement system in a universal health care program in the United States. An all-payer system would keep intact the current array of private and public insurers, but would require that they each pay the same price for hospital and physician services. The article concludes that an all-payer system would face far fewer political barriers than a purely government-financed system. Furthermore, it has a number of advantages over the financing schemes currently used, particularly with respect to enhancing access to care and controlling costs. But there are several potential problems: agreeing on a common payment rate; controlling the volume of services provided; devising a way of incorporating alternative delivery systems; and dealing with the issue of whether providers will be able to "balance bill". The extent to which these problems can be solved will, to a large degree, determine whether an all-payer system can live up to its promise.

Cost Control↗
PubMed1991

Familial aggregation of lipids and lipoproteins in families ascertained through random and nonrandom probands in the Stanford Lipid Research Clinics Family Study.

We examined the familial aggregation of lipids [total cholesterol (CH) and triglyceride (TG)] and lipoproteins [high-density lipoprotein cholesterol (HDL) and low-density lipoprotein cholesterol (LDL)] in families ascertained through random and nonrandom probands in the Stanford Lipid Research Clinics Family Study. Nonrandom probands were selected because their lipid levels at a prior screening visit exceeded a certain prespecified threshold. The statistical method is based on selection through indirect truncation on a correlated trait (in which the likelihood function is conditioned on the actual event that the proband's value is beyond the threshold). This method allows for estimation of the path model parameters in randomly and nonrandomly ascertained families jointly and separately, thus enabling tests of heterogeneity between the two types of samples. The results suggest that the multifactorial transmission is homogeneous in the random and hyperlipidemic samples for CH. However, the evidence for heterogeneity is moderate for LDL, marked HDL, and mixed for TG. The general pattern of observed results is for somewhat higher genetic heritabilities in the random than nonrandom samples, which is compatible with a higher prevalence in the random sample of certain dyslipoproteinemias associated with nonelevated lipids. Substantial genetic heritability is found for CH, HDL, and LDL, with somewhat lower estimates for TG. Cultural heritability is low but significant for all four traits. Little or no spouse resemblance or nontransmitted shared sibship effects are seen. In contrast to the findings from previous studies, little or no parental cultural transmission is seen.

Adult↗
PubMed1991

Chronic postoperative endophthalmitis associated with Actinomyces species.

Actinomyces species, gram-positive, non-spore-forming anaerobic bacilli were isolated from intraocular fluid obtained from four otherwise healthy patients with a delayed onset of postoperative endophthalmitis. One patient had a mixed anaerobic infection with recovery of both Actinomyces israelii and Propionibacterium acnes. In all four patients, early postoperative visual acuity was good but was eventually markedly reduced by intraocular inflammation that was first observed between 21 days and 4 months following uneventful extracapsular cataract extraction and posterior chamber intraocular lens implantation. Inflammation was characterized by anterior segment and vitreous cellular debris in all cases. All eyes responded to therapy that included intraocular, topical, and systemic antibiotics as well as pars plana vitrectomy and partial iridectomy. These cases further illustrate the need for microbiologic investigation, including anaerobic cultures, in all cases of chronic postoperative inflammation following extracapsular cataract extraction, regardless of the time of onset.

Actinomyces↗
PubMed1991

Determinants of health insurance status among young adults.

This study evaluates the determinants of insurance coverage in the 18-24-year-old population using the National Medical Care Utilization and Expenditure Survey. Three specific issues are addressed: 1) the characteristics of the insured versus uninsured, 2) the reason given by the uninsured for not having coverage, and 3) the role of employment status and other variables in determining insurance status. An important consideration is whether age or usual activity is more important in its effect on insurance status. The results show that employment is the strongest predictor of insurance status in all age and usual activity subgroups. Generally, permanent/full-time workers are most likely to be insured. An exception to this trend is found for those attending school who are also permanent/part-time workers. These individuals are more likely to be insured than permanent full-time workers who are in school. Furthermore, young adults with lower incomes, less education, rural residence, not married, hispanic ethnicity, and Western geography are the least likely to be insured. The findings of this analysis can be used by policymakers to identify the mechanisms that can best enhance insurance coverage among young adults.

Adult↗
PubMed1991

Prostaglandins in experimental syphilis: treponemes stimulate adherent spleen cells to secrete prostaglandin E2, and indomethacin upregulates immune functions.

Incubation of microorganisms with macrophages enhances the production of prostaglandin E2 (PGE2). Previous research had indicated that macrophages from syphilitic rabbits suppressed spleen cell synthesis of interleukin-2 (IL-2); this suppressive activity was reversed by indomethacin. Experiments were designed to further characterize the involvement of prostaglandins in immune processing. When Treponema pallidum was incubated with unfractionated spleen preparations, PGE2 production was accelerated, and within 24 h, pharmacologic concentrations of the prostaglandin were detected. When cytochalasin B was used to block phagocytosis, decreased levels of PGE2 were apparent. Commercial preparations of PGE2, in the range generated by macrophage-treponeme interaction, inhibited concanavalin A-induced IL-2 secretion by splenic cells. T. pallidum stimulated IL-1 production by adherent cells, and indomethacin markedly enhanced this effect. In vivo, indomethacin upregulated immune function. Two groups of rabbits were infected, and one was given daily injections of indomethacin for 18 days. Both groups were treated with penicillin to terminate infections. One week later, rabbits were challenged with viable organisms to determine their immune status. The indomethacin-treated group was more resistant to reinfection. In further research, indomethacin enhanced the immunogenicity of vaccine preparations containing heat-killed T. pallidum. Results are discussed in terms of the role of PGE2 as it impinges on immune functions involving macrophage activation (IL-1 production) and T lymphocyte activation (IL-2 production).

Animals↗
PubMed1991

Familial aggregation of lipids and lipoproteins in families ascertained through random and nonrandom probands in the Iowa Lipid Research Clinics family study.

The aggregation of lipids [total cholesterol (CH) and triglyceride (TG)] and lipoproteins [high-density lipoprotein cholesterol (HDL) and low-density lipoprotein cholesterol (LDL)] in families ascertained through random and nonrandom probands in the Iowa Lipid Research Clinics family study was examined. Nonrandom probands were selected because their lipid levels (at a prior screening visit) exceeded a certain pre-specified threshold. The statistical method conditions the likelihood function on the actual event that the proband's value is beyond the threshold. This method allows for estimation of the path model parameters in randomly and nonrandomly ascertained families jointly and separately, thus enabling tests of heterogeneity between the two types of samples. Marked heterogeneity between the random and the hyperlipidemic samples is detected in the multifactorial transmission for TG and HDL, and moderate heterogeneity is detected for CH and LDL, with a pattern of higher genetic heritability estimates in the random than nonrandom samples. The observed pattern of heterogeneity is compatible with a higher prevalence in the random sample of certain dyslipoproteinemias that are associated with nonelevated lipids. For the random samples, genetic heritabilities are higher for CH and HDL (about 60%) than for TG and LDL (about 50%). For the nonrandom samples those estimates are about 45, 40, 35 and 30% for HDL, CH, LDL and TG, respectively. Little to no cultural (familial environmental) heritability is evident for CH and LDL, although 10-20% of the phenotypic variance is due to cultural factors for TG and HDL. These results suggest that the etiologies for lipids and lipoproteins may be quite different in random versus hyperlipidemic samples.

Adult↗
PubMed1991

Commingling analysis of generalized body mass and composition measures: the Québec Family Study.

Human body mass and composition are heterogeneous phenotypes resulting from the combined effects of genes, environmental factors, and their interactions. In order to gain an understanding of the individual genetic determinants leading to obesity, we have initiated a systematic analysis of several measures of fatness and its phenotypes including: the body mass index (wt/ht2), fat mass, fat-free (lean) mass, the ratio of fat mass over fat-free mass, percent body fat, and a fat mass index (fat mass/ht). In this report, we examine the distributions of these age and sex adjusted variables in a large family study from Québec in terms of evidence for commingling and skewness, and evaluate the inter-relationships among the measures. Fat mass, fat-free mass and the fat mass index conceptually represent primary variables in that they are quantitative measures of relevant components of total body weight; the hypothesis of a single distribution was inferred for each of these primary measures, with significant residual skewness except for fat mass. In general, offspring (8-26 years old) distributions were more positively skewed than parent (30-60 years old) distributions. The remaining variables (body mass index, fat mass to fat-free mass ratio, and percent body fat) are indexes combining information on fat and fat-free mass into single measures. Although offspring data were consistent with a single skewed distribution, commingling was found in the parents in each case. The prominent heterogeneity between generations suggests that there may be significant developmental (genetic or environmental) effects in the transition during growing years to adult pattern phenotypes, particularly for the complex indicators of body composition.

Adipose Tissue↗
PubMed1991

Private health insurance and medical care utilization: evidence from the Medicare population.

This paper examines the impact of supplemental health insurance policy ownership on the use of health care services by the elderly. It employs a data base consisting of Medicare claims data from over 2,000 beneficiaries in six states, actual copies of their supplemental insurance policies, and detailed survey information. The results show that policy ownership has a substantial, positive impact on service usage and costs, particularly for beneficiaries in fair or poor health. The greatest impact was found for policies that provide first-dollar coverage.

Aged↗
PubMed1991

Familial aggregation of lipids and lipoproteins in families ascertained through random and nonrandom probands in the Minnesota Lipid Research Clinic Family Study.

The familial aggregation of lipids [total cholesterol (CH) and triglyceride (TG)] and lipoproteins [high-density lipoprotein cholesterol (HDL) and low-density lipoprotein cholesterol (LDL)] was investigated in families ascertained through both random and nonrandom probands in the Minnesota Lipid Research Clinic Family Study. Nonrandom proband ascertainment was based on single selection through truncation for hyperlipidemia at an earlier screening. A path model was used to investigate the nature of familial resemblance using appropriate adjustments for ascertainment and to determine whether random and hyperlipidemic samples are heterogeneous with regard to the multifactorial model. The results suggest that parameter estimates are consistent with those from previous studies in which only random families were used and that random and nonrandom samples are homogeneous with regard to the path model for CH and LDL. However, for TG and HDL the random and hyperlipidemic samples are significantly heterogeneous. This heterogeneity would be observed if familial hypertriglyceridemia and/or familial hypoalphalipoproteinemia segregates predominantly in the hyperlipidemic rather than in the random sample, as on might expect.

Chromosome Banding↗