Reinforcement of weakened cusps by adhesive restorative materials: an in-vitro study

Pairs of extracted premolar teeth were prepared with MOD cavities reducing the lingual cusp at its base to one of five widths: 1.25-2.25 mm. One of each pair was then restored with one of five adhesive restorative techniques and the weakened cusp of both teeth fractured by a force applied to the cusp at an angle of 30 degrees to the long axis of the tooth. At all cusp widths a layered restorative technique in which the cavities were filled to the enamel-dentine junction with glass-ionomer cement and the enamel replaced by composite, reinforced the weakened cusp more than the other restorative materials tested. This combination of materials to reinforce weakened cusps is worth considering as a cost effective alternative to removing the cusp entirely and making a crown or protecting the cusp with a cuspal coverage gold inlay.     

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.     

Pathogenesis of chronic allograft nephropathy

We found normal individuals whose aspartoacylase gene Y231X mutation site consistently gave no signal in a primer extension assay. We determined the nucleotide sequence of the relevant region of the gene in those individuals, and found a new allele with a thymidine residue at the mutation site instead of a cytidine. Since both TAC and TAT code for tyrosine, this sequence polymorphism has no effect on the amino acid sequence of the ASPA protein. We found the relative frequencies of the 693C and the 693T alleles in the tested population to be 0.75 and 0.25 respectively.     

Approach and avoidance strength during goal attainment: regulatory focus and the "goal looms larger" effect

Three studies tested the hypothesis that regulatory focus, both as a chronic person variable and as a manipulated situational variable, differentially affects the strength of participants' approach and avoidance strategic motivations as they get closer to the goal. In 2 studies, flexion and extension arm pressure were used as on-line measures of approach and avoidance intensity, respectively. As predicted, the approach gradient was steeper for participants with a promotion focus on aspirations and gains than for participants with a prevention focus on responsibilities and nonlosses, whereas the reverse was true for the avoidance gradient. In a third study, the same pattern of results was found on a persistence measure of motivational strength. Participants with a promotion focus worked longer on anagrams closer to the goal when they were approach means for goal attainment than when they were avoidance means, whereas the reverse was true for participants with a prevention focus.     

Epidemiology of work-related aviation fatalities in Alaska, 1990-94

Alaska, with less than one-half of 1% of the United States workforce, accounts for 9% of all occupational aviation fatalities nationally; 30% of all occupational fatalities in Alaska are related to aviation. To understand this high mortality, we investigated occupational aviation crashes to identify risk factors. Occupational aviation fatalities in Alaska during 1990-94 were examined using National Transportation Safety Board reports and merged with records from the Alaska Occupational Injury Surveillance System. There were 876 aircraft crashes; 407 (46%) were work-related. Occupational crashes were 2.2 times (CI: 1.5, 3.2) more likely to result in fatalities than non-occupational crashes. Risk factors identified included poor weather conditions defined as Instrument Meteorological Conditions (IMC). A crash during IMC was 5.3 times (CI: 3.5, 7.9) more likely to result in fatalities than crashes in other conditions. Of aircraft involved in fatal occupational incidents, 33% were not completely destroyed, allowing the potential for survivors. An estimated 30% reduction in fatalities could have occurred if current technology in occupant protection had been used.     

Month of birth and schizophrenia in Taiwan: effect of gender, family history and age at onset

Schizophrenic patients have been shown to have a moderate excess of winter births in the areas where seasonal variations in weather are large. In this report, we examined the seasonality of schizophrenic births in Taiwan, which has a subtropical climate. Using nationwide hospitalization data (2429 male and 1320 female schizophrenic patients), we applied the life table method to compare the risk of schizophrenia among 12 cohorts of month-of-birth for males and females, respectively. Differences among the risks of the 12 cohorts were tested using the logrank test. The samples were further stratified by family history and age at onset. There was a significant association between the risk of being admitted as a schizophrenic and month of birth for both males and females. The cohorts born in November and January had the highest risks. After stratification, the association was significant only for non-familial, male, and early onset schizophrenic patients. The results indicate that seasonally varying factors might increase the risk of schizophrenia, especially in those without a family history of the disease. Men are more vulnerable to such factors than women, and the schizophrenics resulting from such insults tend to be early onset.     

Severing of F-actin by the amino-terminal half of gelsolin suggests internal cooperativity in gelsolin

Gelsolin is a Ca2+-regulated actin-binding protein that can sever, cap, and nucleate growth from the pointed ends of actin filaments. In this study we have measured the binding of the amino-terminal half of gelsolin, G1-3, to pyrene-labeled F-actin as a function of Ca2+ concentration. The rate of binding is shown to be dependent on micromolar concentrations of Ca2+. Independent experiments demonstrate that conformational changes in G1-3 are induced by micromolar concentrations of Ca2+. Titrations of pyrene-F-actin with G1-3 and gelsolin show that the quenching of pyrene fluorescence is identical in extent and stoichiometry for both G1-3 and gelsolin. In contrast, severing of F-actin by G1-3 is found to be much less efficient than is severing by gelsolin. In experiments in which F-actin severing is quantitatively measured, the filament number is found to be proportional to the 1.35 power of the G1-3 concentration. This deviation from linearity may be explained by cooperativity; the binding of two G1-3 molecules in close proximity may lead to cooperative severing of the polymer, thus increasing the severing efficiency. This model is supported by experiments that show that the efficiency of G1-3 severing of F-actin increases with increasing G1-3:F-actin ratios. Extrapolating from these results, we conclude that G4-6, the carboxyl-terminal half of gelsolin, has an active role in the severing of F-actin by intact gelsolin. Whereas F-actin severing by G1-3 is enhanced by cooperative binding of two separate G1-3 molecules, cooperativity is inherent to intact gelsolin because the cooperative partners are covalently linked.     

Clinical presentation of experimentally induced rabies in horses

Twelve naive and nine test-vaccinated horses which developed clinical signs of rabies as a result of the required protocol of a vaccine trial were prospectively observed. Nineteen of the 21 cases were confirmed positive for rabies infection of the brain by fluorescent antibody test. The two horses with negative results had ganglioneuritis of the trigeminal ganglion or lymphocytic perivascular cuffing in the brain stem in addition to clinical signs. Average incubation period was 12.3 days and average morbidity was 5.5 days. Naive animals had significantly shorter incubation and morbidity periods (P < 0.05). Muzzle tremors were the most frequently observed (81%) and most common initial sign. Other common signs were pharyngeal spasm or pharyngeal paresis (71%), ataxia or paresis (71%), lethargy or somnolence (71%). The furious form was manifested in 43% of rabid horses and some of these furious animals initially manifested the dumb form. The paralytic form was not observed. Histopathology was characteristics for rabies. The results of this trial do not reflect on the efficacy of commercially licensed equine rabies vaccines.