Vagal regulation during bottle feeding in low-birthweight neonates: support for the gustatory-vagal hypothesis

BACKGROUND AND PURPOSE: Linear accelerators equipped with multileaf collimators (MLCs) are becoming more common and are widely available from most commercial manufacturers. There is a need to ensure they retain their commissioning specification using a preventative maintenance and quality control (QC) programme. This paper considers the design criteria of the Philips MLC which are important to the production of a comprehensive quality control programme. MATERIALS AND METHODS: The specific QC problems related to MLCs are identified as the positional accuracy of the leaves and their relationship to the back-up collimators, leakage considerations, the relationship of X-ray to light field and the influence of gravity on the positioning and leakage characteristics of the leaves. These problems are considered in relation to the general design considerations of the MLC, and methods of performing routine quality control checks are discussed. RESULTS AND CONCLUSIONS: The introduction of MLCs into clinical use results in new QC procedures being developed but it can be concluded that for the Philips MLC only an extra 30 min of QC time is needed per month and that its use has added little to the general down-time of this department.     

Validity of screening for individuals at risk for type I diabetes by combined analysis of antibodies to recombinant proteins

OBJECTIVE: To determine whether screening for the presence of multiple antibody markers for IDDM is effective at identifying individuals with high risk for disease development. RESEARCH DESIGN AND METHODS: Antibodies to GAD and the tyrosine phosphatase-like protein 1A-2 were determined in sequential serum samples from 44 first-degree relatives of IDDM patients, identified as possessing islet cell antibody (ICA) and/or insulin autoantibody (IAA), who were followed prospectively for IDDM development, ICA, IAA, and antibodies to GAD and 1A-2 were also determined in 93 cases of new-onset nonfamilial IDDM. RESULTS: The presence of two or more antibodies in addition to ICA or IAA conferred high risk (61%) for development of IDDM within 5 years of entry into the study and identified 89% of those who have developed IDDM on current follow-up. None of the relatives positive for ICA or IAA alone, in the absence of other antibody markers, have developed IDDM. Antibodies to islet antigens could both appear and disappear in follow-up samples obtained after entry into the study. The majority (60%) of young (< 16 years), sporadic cases of IDDM had multiple antibodies to islet antigens, but this proportion was lower in older patients (37%). CONCLUSIONS: A screening strategy based on the analysis of antibodies to multiple islet antigens can predict IDDM at high sensitivity and specificity in families, and such a strategy may also be applicable to identify young individuals in the general population with high disease risk. Since appearance of antibodies to different antigens occurs sequentially rather than simultaneously, accurate assessment of diabetes risk based on the presence of multiple antibodies will require follow-up over a number of years after the first evidence of islet autoimmunity.     

Cross-clade human immunodeficiency virus (HIV)-specific cytotoxic T-lymphocyte responses in HIV-infected Zambians

We have examined cross-clade HIV-specific cytotoxic T-lymphocyte (CTL) activity in peripheral blood of eight Zambian individuals infected with non-B-clade human immunodeficiency virus type 1 (HIV-1). Heteroduplex mobility assay and partial sequence analysis of env and gag genes strongly suggests that all the HIV-infected subjects were infected with clade C HIV-1. Six of eight C-clade HIV-infected individuals elicited CTL activity specific for recombinant vaccinia virus-infected autologous targets expressing HIV gag-pol-env derived from B-clade HIV-1 (IIIB). Recognition of individual recombinant HIV-1 B-clade vaccinia virus-infected targets expressing gag, pol, or env was variable among the patients tested, indicating that cross-clade CTL activity is not limited to a single HIV protein. These data demonstrate that HIV clade C-infected individuals can mount vigorous HIV clade B-reactive CTL responses.     

Changes in carotenoid intake in the United States: the 1987 and 1992 National Health Interview Surveys

OBJECTIVES: To assess the changes in carotenoid intake between 1987 and 1992 among US adults by sociodemographic characteristics and high-risk groups for chronic disease; and to identify the dietary sources of specific carotenoid intake. DESIGN: A food frequency questionnaire (FFQ) was collected from a representative sample of respondents to the 1987 and 1992 National Health Interview Surveys throughout two calendar quarters. Black and white adults, 18 to 69 years old, participated in 1987 (n = 8,161) and 1992 (n = 8,341). METHOD: FFQ data were matched and linked to the US Department of Agriculture-National Cancer Institute carotenoid food composition database for analysis. STATISTICAL ANALYSIS: Mean differences in carotenoid intake over time were compared by sociodemographic characteristics and region of the country, after adjustment for sampling weights in a multiple linear regression model. RESULTS: Mean intake of the carotenoid lutein declined among white women (18%), among adults aged 40 to 69 years (16%), among persons with 9 to 12 years of education (11%), among nondrinkers (18%), among drinkers of 1 to 6 alcoholic drinks/ week (7%), among smokers (former smokers by 11%, current smokers by 7%, and never smokers by 9%), among income groups (< $20,000 by 7%, > or = $20,000 by 9%), and residents in the south and northeast (by 13% each, respectively). Mean intake of the carotenoid lycopene increased among white men (9%), among adults aged 18 to 39 years and aged 40 to 69 years (by 5% and 6%, respectively), among those with 13 years of education or more (12.5%), among alcohol drinkers (by 10% and 7% for 1 to 6 vs 7 or more drinks/week, respectively), among former and current smokers (by 6% each), among those with incomes > or = $20,000 (8%), and among residents in the west (16%) and midwest (5%). All differences described were statistically significant (P < .01). APPLICATION: The decline in lutein intake (from dark green leafy vegetables), particularly in white women, may have public health implications as a result of the recognized inverse association between carotenoid intake and disease risk.     

Effect of obesity on the response to insulin therapy in noninsulin-dependent diabetes mellitus

An initial improvement in glycemic control is often followed by gradual deterioration of glycemia during insulin treatment of patients with noninsulin-dependent diabetes mellitus (NIDDM). We examined the causes of such worsening in a 12-month follow-up analysis of 100 insulin-treated NIDDM patients in the Finnish Multicenter Insulin Therapy Study who were treated with either combination therapy with insulin or insulin alone. In the entire study group, glycemic control averaged 9.7 +/- 0.2% at 0 months and 8.0 +/- 0.1%, 8.0 +/- 0.1%, 8.2 +/- 0.1%, and 8.5 +/- 0.2% at 3, 6, 9, and 12 months (P < 0.001 for each time point vs. 0 months). Glycemic control at 12 months was significantly worse than that at 3 (P < 0.001), 6 (P < 0.001), and 9 months (P < 0.02). Baseline body mass index was the most significant predictor of deterioration in glycemic control. During 1 yr, hemoglobin A1c decreased almost 3-fold more (by 1.7 +/- 0.2%; P < 0.001 vs. 0 months) in patients whose baseline weight was below the mean baseline body mass index of 28.1 kg/m2 (nonobese patients) than in those whose weight exceeded 28.1 kg/m2 (obese patients; 0.5 +/- 0.2%; P = NS vs. 0 months; P < 0.01 vs. obese patients). Glycemic control improved similarly over 1 yr in the nonobese subjects and deteriorated similarly in the obese patients regardless of their treatment regimen. Insulin doses, per body weight, were similar in the nonobese and obese patients. The nonobese patients consistently gained less weight during 12 months of combination therapy with insulin (3.5 +/- 0.6 kg at 12 months) than during insulin therapy alone (5.1 +/- 0.6 kg; P < 0.05). The treatment regimen did not influence weight gain in the obese group, who gained 4.4 +/- 1.0 kg during combination therapy with insulin and 4.5 +/- 1.1 kg during insulin therapy alone. We reached the following conclusions: 1) after an initial good response, glycemic control deteriorates more in obese than in nonobese patients with NIDDM; 2) in obese patients, weight gain per se cannot explain the poor glycemic response to combination or insulin therapy, but it may induce a disproportionately large increase in insulin requirements because of greater insulin resistance in the obese than in the nonobese; 3) in nonobese patients, glycemic control improves equally during 1 yr with combination therapy with insulin and insulin alone, but combination therapy with insulin is associated with less weight gain than treatment with insulin alone; 4) weight gain appears harmful, as it is associated with increases in blood pressure and low density lipoprotein cholesterol.     

Creep Behavior in Interlaminar Shear of a SiC/SiC Ceramic Composite with a Self-healing Matrix

Creep behavior in interlaminar shear of a non-oxide ceramic composite with a multilayered matrix was investigated at 1,200 °C in laboratory air and in steam environment. The composite was produced via chemical vapor infiltration (CVI). The composite had an oxidation inhibited matrix, which consisted of alternating layers of silicon carbide and boron carbide and was reinforced with laminated Hi-Nicalon? fibers woven in a five-harness-satin weave. Fiber preforms had pyrolytic carbon fiber coating with boron carbide overlay applied. The interlaminar shear properties were measured. The creep behavior was examined for interlaminar shear stresses in the 16–22 MPa range. Primary and secondary creep regimes were observed in all tests conducted in air and in steam. In air and in steam, creep run-out defined as 100 h at creep stress was achieved at 16 MPa. Larger creep strains were accumulated in steam. However, creep strain rates and creep lifetimes were only moderately affected by the presence of steam. The retained properties of all specimens that achieved run-out were characterized. Composite microstructure, as well as damage and failure mechanisms were investigated.