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Biomedical subjects

G Block

Publications and source records attributed to G Block.

At least 19 recordsLinked to original sources
PubMed1997

Incorporating fat-modified foods into a food frequency questionnaire improves classification of fat intake.

OBJECTIVE: To determine the extent to which incorporating fat-modified foods into a food frequency questionnaire influences the agreement of energy and nutrient estimates with estimates obtained from food records. DESIGN: Subjects completed four 2-day food records at 3-month intervals. At the end of the recording period, a food frequency questionnaire was administered to assess usual daily intake during the preceding year. SUBJECTS/SETTING: One hundred and three subjects selected from a population-based sample of adults participating in the Beaver Dam Eye Study. STATISTICAL ANALYSES PERFORMED: Subjects were categorized into three groups on the basis of their frequency of consumption of fat-modified foods. For each group, correlations were calculated between food record estimates and estimates obtained from the original food frequency questionnaire, the original with a low-fat option, and the fat-modified questionnaire. RESULTS: For persons categorized as high consumers of fat-modified foods, incorporating questions regarding the consumption of these products resulted in higher correlations with food record estimates (original vs fat-modified version) for percentage of energy from total fat (.32 vs .47), saturated fat (.20 vs .41), oleic acid (.32 vs .50), and linoleic acid (.40 vs .46). High consumers differed in several characteristics that could be associated with disease risk (eg, higher ratios of serum total cholesterol to high-density lipoprotein cholesterol). CONCLUSIONS: Failure to account for the consumption of fat-modified foods in epidemiologic studies may result in misclassification of fat exposures. Because patterns of misclassification could be different for those at risk for disease, results of epidemiologic studies could be biased if these foods are excluded. Thus, incorporating fat-modified foods into food frequency questionnaires will improve the ability of researchers to correctly classify fat exposures and to evaluate potentially important relationships between fat intake and disease risk.

Aged↗
PubMed1997

Trends in food intake: the 1987 and 1992 National Health Interview Surveys.

To examine food intake trends in the US population, cross-sectional nationally representative food intake data were obtained from the 1987 and 1992 National Health Interview Survey Cancer Control Supplements. In each of these years, approximately 10,000 respondents completed methodologically consistent food frequency questionnaires containing the same 57 food items. Between 1987 and 1992, the proportion of Americans consuming high-fat foods, including fried fish, fried chicken, bacon, eggs, whole milk, and butter, decreased. The proportion of Americans drinking alcoholic beverages also decreased: fewer drank wine and hard liquor in 1992. The proportion of fruit and vegetable consumers remained stable over time. These results are similar to those obtained from more detailed national surveys. National guidelines urge Americans to avoid intake of high-fat foods, increase consumption of fruits and vegetables, and practice moderation when drinking alcoholic beverages to prevent cancer and other chronic diseases. The direction of Americans' apparent changes in food usage between 1987 and 1992, evaluated using limited data from food frequency questionnaires, suggests greater behavioral changes in the direction of guidelines recommending avoidance of foods that may increase the risk of cancer than in the direction of guidelines recommending increased consumption of foods that may confer protection.

Adolescent↗
PubMed1997

Comparison of immediate-release and controlled release carbidopa/levodopa in Parkinson's disease. A multicenter 5-year study. The CR First Study Group.

BACKGROUND: Motor response fluctuations and dyskinesias compromise long-term levodopa therapy in Parkinson's disease. Variations in plasma levodopa levels contribute to adverse reactions associated with chronic therapy. Therefore, sustained-release levodopa preparations may be associated with less motor fluctuations and a better outcome. We conducted a large, 5-year, multicenter study to address this hypothesis. METHODS: Six hundred and eighteen nonfluctuating patients with Parkinson's disease never exposed to levodopa therapy were randomized to (Sinemet CR 50/200) sustained-release or immediate-release (Sinemet 25/100) carbidopa/levodopa preparations in 35 centers worldwide. Dosage titration occurred over the 5 years of evaluations to maintain an optimal response. The primary endpoint, the 'event', was the presence of motor fluctuations, as defined by 20% 'off' time or 10% 'on' time with dyskinesias as recorded in the patient diary, or greater than or equal to a 50% positive response on the physician fluctuations questionnaire. Clinical rating scales, Nottingham Health Profile (NHP) and adverse reactions were also recorded. FINDINGS: During the 5 years of the study, both treatment groups responded extremely well to therapy. The incidence of all patients reaching the 'event' was low, approximately 20% by diary criteria and 16% by questionnaire definition, and there was no significant difference between the two treatment groups. Activities of daily living scores in the Unified Parkinson Disease Rating Scale (UPDRS) consistently favored the Sinemet CR treatment group and a number of the NHP scales also favored the CR group. Based upon the frequency of adverse experiences, and the overall low incidence of withdrawals, the two treatment groups demonstrated very similar safety profiles. The most common drug-related effect was nausea; seen in 20% of patients. Other drug-related effects were dizziness, insomnia, abdominal pain, dyskinesia, headache and depression. Drug-related withdrawals were less than 10% of all patients, primarily due to nervous/psychiatric complaints. INTERPRETATION: During a 5-year treatment period, control of parkinsonian symptoms was maintained by both immediate-release and sustained-release carbidopa/levodopa. Both treatment regimens were associated with a low incidence of motor fluctuations and dyskinesias. There was a statistically significant difference (p < 0.05) in activities of daily living as measured by the UPDRS in favor of Sinemet CR.

Activities of Daily Living↗
PubMed1997

US trends in nutrient intake: the 1987 and 1992 National Health Interview Surveys.

OBJECTIVES: This study examined US trends in nutrient intake, using almost identical methods and nutrient databases in two time periods. METHODS: An extensive dietary intake questionnaire was included in supplements to the 1987 and 1992 National Health Interview Surveys. Dietary data from approximately 11,000 persons in each of those years were analyzed. RESULTS: The total and saturated fat intake and the percentage of energy from fat declined among Whites and Hispanics, but only minimal changes were seen in Black Americans. The changes in fat intake were attributable principally to behavioral changes in frequency and type of fat-containing foods consumed rather than to the increased availability of leaner cuts of meat. Dietary cholesterol showed one of the largest declines of the nutrients examined. Less desirable changes were also seen. Cereal fortification played an important role in the observed changes in several micronutrients. CONCLUSIONS: Educational campaigns on dietary fat and cholesterol have been moderately effective, but not in all racial/ethnic groups. Future campaigns should emphasize maintaining or increasing micronutrient intake.

Adult↗
PubMed1996

Use of extracorporeal shock wave lithotripsy for treatment of nephrolithiasis and ureterolithiasis in five dogs.

The safety and efficacy of extracorporeal shock wave lithotripsy in 5 dogs with nephrolithiasis and ureterolithiasis was assessed. Three dogs had bilateral nephrolithiasis, 1 had bilateral nephrolithiasis and unilateral ureterolithiasis, and 1 had unilateral nephrolithiasis and unilateral ureterolithiasis. A first-generation lithotriptor was used for all treatments. None of the dogs developed clinically important complications during or after treatment, except for 1 dog treated for bilateral nephrolithiasis that developed transient ureterolithiasis. Renal function was unchanged in all dogs following treatment. Clinical signs resolved in all dogs. Extracorporeal shock wave lithotripsy appears to be a safe and effective means of treating nephrolithiasis and ureterolithiasis in dogs and appears to cause less renal parenchymal damage and renal function loss than does nephrotomy.

Animals↗
PubMed1996

Influence of using different sources of carotenoid data in epidemiologic studies.

OBJECTIVE: This study compared distributions of carotenoid intake and diet-serum correlations using two sources of carotenoid data: the US Department of Agriculture-National Cancer Institute (USDA-NCI) carotenoid food composition database and values accompanying the Block-NCI Health Habits and History Questionnaire (HHHQ). DESIGN AND SUBJECTS: A 100-item food frequency questionnaire was used to collect dietary data from 2,152 adults, aged 43 to 85 years, who were participating in the Nutritional Factors in Eye Disease Study, a population-based study designed to evaluate nutritional factors associated with age-related eye disease. Blood samples were collected from a random sample of 400 nonfasting participants in the study. RESULTS: Median carotenoid intakes using HHHQ vs USDA-NCI data were alpha carotene (229 vs 223 micrograms/day), beta carotene (1,321 vs 1,325 micrograms/day), beta cryptoxanthin (72 vs 21 micrograms/day), lutein + zeaxanthin (653 vs 811 micrograms/day), and lycopene (593 vs 1,615 micrograms/day). all paired differences in carotenoid intake were significantly different from zero (Wilcoxon signed-rank, P < .0001). Despite these differences, the two databases similarly ranked individuals according to carotenoid intake: Spearman correlations ranged from .71 (lycopene) to .93 (alpha carotene). Differences between diet-serum correlations (adjusted for energy, body mass index, high density lipoprotein, and total cholesterol) using HHHQ vs USDA-NCI data were minor and not significant (P > .05): alpha carotene (r = .33 vs .32), beta carotene (r = .27 vs .32), beta cryptoxanthin (r = .48 vs .53), lutein+zeaxanthin (r = .28 vs .24), and lycopene (r = .29 vs .25). CONCLUSIONS: Although estimates of carotenoid intake differed significantly, only minor differences in carotenoid rankings and diet-serum correlations were observed using either data source in this population.

Adult↗
PubMed1996

Pilot study of MK-462 in migraine.

MK-462 is a potent, selective 5HT1D receptor agonist which may be useful in treating acute migraine. We conducted a double-blind placebo-controlled inpatient study to assess the preliminary efficacy and safety of oral doses of MK-462 20 mg (n = 8) and 40 mg (n = 36) vs placebo (n = 21), administered to 65 male and post-menopausal female migraine patients aged 22-51 with moderate or severe migraine headache. Headache severity and functional disability were measured at 0.5, 1, 1.5, and 2 h post-dose. The 20 mg dose was well tolerated and 4/8 patients obtained relief in headache severity at the 2 h time point. The 40 mg dose was well tolerated and was significantly (p < 0.05) superior to placebo at the 1.5 and 2 h time points (with 27/36 or 75% obtaining relief at 2 h compared to 7/21 or 33% for placebo). Adverse events occurred in 50% of patients on 20 mg MK-462, 72% of those on 40 mg MK-462, and in 52% of placebo-treated subjects. The most common adverse events associated with MK-462 were drowsiness (20 mg 12%; 40 mg 44%; placebo 24%), dry mouth (40 mg 36%; placebo 19%), and lightheadedness/dizziness (40 mg 17%; placebo 10%). Based on these preliminary results, MK-462 appears worthy of continued study for the treatment of acute migraine.

Adult↗
PubMed1996

Reproducibility of a self-administered diet history questionnaire administered three times over three different seasons.

The reproducibility of the widely used Health Habits and History Questionnaire (HHHQ) for estimating "usual past-year" nutrient intake was examined. The HHHQ was self-administered on three occasions during three different seasons; 68 women (avg age 43 yrs) provided usable data for all three questionnaires in the appropriate seasons. Intraclass correlations (ICC) among the three administrations ranged from 0.56 (carotene) to 0.82 (fat as percentage of energy), with a median of 0.72. Thus, reliability was moderate to good, and season of administration/ordinality generally had little impact on ranking of individuals. The point estimates of intake of energy and a number of nutrients were higher in the first administration (winter). Except for dietary fiber and possibly carotene, most differences disappeared when adjusted for energy using a nutrient density approach, as well as using repeated-measures regression models. The higher intake in the first administration may be due more to either learning or fatigue effect rather than an effect of seasonal food availability on perceptions of "usual" intake. These data should be used in conjunction with validity data in the future to help evaluate the gain in precision of group means (and changes in these means) and improved estimates of odds ratios and correlations between nutrients and factors such as serum values, if a questionnaire is administered more than once.

Adult↗
PubMed1996

Phytoestrogen content of foods--a compendium of literature values.

Plant compounds with estrogenic activity may play a role in cancer prevention, moderation of menopausal symptoms, and other health effects. To facilitate research on these possible actions, the literature was reviewed for quantitative data on the levels of known phytoestrogens (daidzein, genistein, coumestrol, formononetin, and biochanin A) in food plants. For comparative purposes, all phytoestrogen levels were recalculated on a wet weight basis. Details on analytic procedures are given as well. High-performance liquid chromatography was the method most often used to analyze these compounds in foods. Most significant sources of isoflavone and coumestan phytoestrogens include soybeans, soy flour, soy flakes, isolated soy protein, traditional soy foods such as tofu and soy drinks, second-generation say foods, sprouts, and other legumes. Finally, medians among reported values of phytoestrogen content are provided for some of the most commonly eaten foods with quantitative data available. These may be used to calculate dietary intake of daidzein, genistein, coumestrol, formononetin, and biochanin A.

Chromatography, High Pressure Liquid↗
PubMed1996

alpha-Interferon retreatment of patients with chronic hepatitis C.

To evaluate the effect of a second cycle of alpha-IFN treatment on patients who have not responded to a first cycle or responded and relapsed, 37 patients, 25 men and 12 women, mean age 41 yr, were retreated with alpha-interferon (IFN). Seven patients responded to the first cycle of treatment, and 30 did not. Five patients who had not responded to the second cycle received a third one. All patients received twice the dose of the first cycle unless they experienced side effects during the first cycle. Thus, nine patients received 9 mU/w, nine received 15 mU/w, and 19 received 30 mU/w for 6 months. Complete response was defined as nondetectable hepatic hepatitis C virus (HCV)-RNA at the end of therapy; sustained response was defined as normal ALT levels with negative serum HCV-RNA at > 6 months after cessation of therapy. Of the 30 nonresponders to the first cycle, eight responded to the second, but only four (13%) had a sustained response. Six of the seven responders to the first cycle responded to the second cycle, but only three had a sustained response (3/7, 43%) (p = NS). Although 33 and 21% (p = NS) of those who were treated with 15 mU/w and 30 mU/w, respectively, showed a sustained response, none of those treated with 9 mU/w had a sustained response (p = NS). Although age or sex of the patients studied had no effect on the response rate, liver histology was an important factor because only noncirrhotics showed a long term response (47 vs 0%; p < 0.02). There was no difference in response rate between patients with chronic active hepatitis and chronic persistent hepatitis. In conclusion, noncirrhotic patients who have not responded or responded and relapsed to a 6-month course of alpha-INF (3-5 mU three times per week) should try a second course at a dose of 15 mU/w. Retreatment may induce complete and long lasting response in 13% of the initial nonresponders and 43% of the initial responders. A second course of alpha-IFN in nonresponding cirrhotics appears ineffective in clearing the virus at the doses used.

Adult↗
PubMed1995

Cellular analysis of a molluscan retinal biological clock.

The eye of the opisthobranch mollusc Bulla gouldiana expresses a circadian rhythm in optic nerve impulse frequency. The circadian rhythm is generated among approximately 100 neurons at the base of the retina referred to as basal retinal neurons. These cells are electrically coupled to one another and fire spontaneous action potentials in synchrony. Basal retinal neurons recorded intracellularly exhibit a circadian rhythm in membrane potential that appears to be driven by a circadian modulation of membrane conductance. Membrane conductance is relatively high during the subjective night and decreases after subjective dawn. Recent experiments in our laboratory indicate that individual basal retinal neurons in culture can express circadian rhythms in membrane conductance. When completely isolated, these cells continue to show circadian conductance changes. These studies provide the first direct demonstration that individual neurons can act as circadian pacemakers. Although the precise details of the mechanism generating the circadian periodicity remain obscure, our research indicates that several transmembrane ionic fluxes are not involved in rhythm generation, but that a transmembrane Ca2+ flux is critical for entrainment. Both transcription and translation appear to play critical roles in generating the circadian cycle.

Animals↗
PubMed1995

Effects of treatment with lovastatin and pravastatin on daytime cognitive performance.

The HMG-CoA reductase inhibitors lovastatin and pravastatin have both proven to be effective and well tolerated in the treatment of hypercholesterolemia. To evaluate whether lovastatin or pravastatin might affect daytime cognitive function, a double-blind, placebo-controlled, two-period, incomplete block, crossover study was performed in 36 patients (24 per treatment) with primary hypercholesterolemia. Patients received placebo, lovastatin (40 mg), or pravastatin (40 mg) for 4 weeks. Following a 1-week washout period, patients were crossed over to either lovastatin, pravastatin, or placebo for an additional 4 weeks. Mental performance tests (digit symbol substitution, choice reaction time, auditory vigilance, selective reminding word recall, finger tapping), visual analogue rating scales, and the Profile of Mood States were administered before test drug administration and after 2 and 4 weeks of each treatment. After 4 weeks, no statistically significant differences between treatments in changes from baseline were observed on any parameter with the exception of digit symbol substitution, for which lovastatin and pravastatin were both significantly better than placebo but did not differ from each other. Low-density lipoprotein cholesterol was reduced 38% by lovastatin and 30% by pravastatin. In summary, neither of these chemically distinct HMG-CoA reductase inhibitors impaired daytime cognitive performance after 4 weeks of treatment in patients with primary hypercholesterolemia.

Adult↗
PubMed1995

[Intra-abdominal bleeding after myocardial infarction with cardiopulmonary resuscitation and thrombolytic therapy].

Adverse effects of resuscitation due to closed-chest cardiac massage are common, and the incidence is increased when an incorrect technique is used. Nevertheless, thrombolytic therapy of a myocardial infarction can become necessary even after cardiopulmonary resuscitation (CPR). In these patients, the risk of thrombolytic therapy-induced bleeding is immanent. CASE REPORTS. Within 9 months, two male patients aged 44 and 52 years were admitted to the intensive care unit after out-of-hospital CPR for myocardial infarction with cardiac arrest. In both cases, thrombolytic therapy was undertaken due to the cardiovascular situation or echocardiographic results. Thrombolytic therapy was successful with regard to the ECG changes, but a few hours later both patients demonstrated increasing cardiovascular instability. After abdominal sonography, intra-abdominal bleeding was suspected. Emergency laparotomy became unavoidable, although the coagulation profile was severely impaired in both patients (Tables 1 and 2). Anaesthetic management was characterised by introduction of central venous and intra-arterial catheters, replacement of volume and oxygen carriers using large-bore IV lines, restoration of coagulation factors with fresh frozen plasma, and the choice of "modified neuroleptanaesthesia" with blood pressure-adjusted, small doses of fentanyl, midazolam, and pancuronium. Intraoperatively, a liver injury due to closed-chest cardiac massage was found in both cases. The postoperative courses were complicated by respiratory problems, which led to prolonged mechanical ventilation, but both patients survived without remarkable neurological deficits. CONCLUSION. In patients with thrombolytic therapy after CPR and persisting cardio-vascular instability, a resuscitation injury with consequent haemorrhagic shock should be suspected. For diagnosis, chest X-ray films and abdominal and thoracic sonography are useful and practicable, even at the bedside. Anaesthetic management should focus on adequate monitoring, replacement of volume and oxygen carriers, fast restoration of plasma coagulation, and careful, blood pressure-adjusted maintenance of anaesthesia.

Abdomen↗
PubMed1995

Sources of energy and six nutrients in diets of low-income Hispanic-American women and their children: quantitative data from HHANES, 1982-1984.

OBJECTIVE: Identification of important food sources of energy, protein, fat, vitamin A, vitamin C, calcium, and iron for low-income Hispanic women and their children. DESIGN: A subset of 24-hour recalls from the Hispanic Health and Nutrition Examination Survey (HHANES), a sample representing 76% of the Hispanic-origin population, provides the most comprehensive examination of Hispanic food habits in the United States. SUBJECTS/SAMPLES: The sample, which approximates the population of the Special Supplemental Food Program for Women, Infants, and Children (WIC), included 1,046 17- to 34-year-old women with household income less than 185% of poverty level and their 1- to 5-year-old children (n = 1,063). MAIN OUTCOME MEASURES: Tables show the percentage that each food contributes to total intake of energy and six nutrients for women and for children and percentage of persons who reported consuming each food during a 24-hour period. RESULTS: Cultural foods contributed less to the energy and nutrient intake of the population than expected, with few exceptions, notably beans, rice, tortillas, and salsa. Major sources of energy and nutrients were similar to those seen for blacks and whites in the second National Health and Nutrition Examination Survey (1976-1980). APPLICATIONS: The data presented should be useful to researchers designing dietary assessment instruments and to nutrition educators designing or adapting educational materials. The data may be of particular interest to WIC staff who work with low-income Hispanic populations.

Adolescent↗
PubMed1995

Food choices of whites, blacks, and Hispanics: data from the 1987 National Health Interview Survey.

Dietary guidelines posit an association between diet and cancer. Different cancer mortality rates among whites, blacks, and Hispanics may be related to differences in diet. Food frequency data from the 1987 National Health Interview Survey on 20,143 adults were used to estimate the percentage of adults, by gender and race/ethnicity, who consume some 59 foods six or more times per year, median number of servings for consumers, and frequency of consumption of skin on poultry and fat on red meat. On the basis of percent consumption of these foods, women appear to have a more diverse diet than men. Women eat more fruits and vegetables, less meat, and fewer high-fat foods and drink fewer alcoholic beverages. Whites eat a more varied diet than blacks and Hispanics; blacks eat more fried and high-fat food; consumption of high-fat foods is lowest among Hispanics. Public health messages, especially those aimed at cancer prevention, should be targeted at increasing the overall consumption of fruits and vegetables, decreasing consumption of high-fat foods, especially among white and black men, and increasing consumption of those healthful foods already consumed by particular race/ethnicity groups.

Black or African American↗