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At least 19 recordsLinked to original sources
PubMed1978

Comparison of blind and non-blind assessments of occlusal sealant retention.

A comparison was made of scoring the retention status of BIS-GMA occlusal sealants 5 years after they had been placed, according to a non-blind and blind method of identification of teeth that had been sealed. Subjects were 175 children ages 15--18. One examiner made all the assessments. Retention of sealant was classified as all present, partly missing or all missing. There was 90.5% complete agreement between non-blind and blind examinations in scoring the retention status of 893 occlusal sites. Essentially no difference in agreement was found between sites on maxillary and mandibular teeth nor according to sites in specific teeth. There was only a slight tendency to classify more sites as having sealant present at the non-blind examinations than at the blind examinations, 56.7% and 55.1%, respectively. These findings would seem to indicate that whether examinations are done blindly or non-blindly is of minor importance in making an accurate assessment of sealant retention.

Adolescent↗
PubMed1977

[Equilibriometric findings in partially blind and blind children (author's transl)].

26 of both blind or partially blind children were subjected to equilibriometric tests. By way of a vestibular-ocular test they were given the Rotatory-Intensity-Damping test. During the tests the per and postrotatory nystagmus reactions were electronystagmographicly registrated. For the vestibular-spinal tests the Unterberger's stepping test with photographic registration of the body-sway in the Cranio-Corpo-Gram was used. In most of the children you could identify a definite per and postrotatory reaction in spite of considerable spontaneous reactions. The strong eyelid movements of these patients, the intensive spontaneous deviations and diminished corneo-retinal potential made precise judgement of the electronystagmogram difficult. Comparison between the blind and partially blind children enabled the differences to be objectified. Blind-born children have a higher spontaneous activity, slightly diminished per and postrotatory nystagmus reactions and a diminished bodyequilibrium. These results can be explained on one side by habituation and on the other side by efferent structures, which have an inhibitory effect on the vestibular input.

Adolescent↗
PubMed1975

Experimental production of elevated serum folate in dogs with intestinal blind loops. II. Nature of bacterially produced folate coenzymes in blind loop fluid.

Jejunal and ileal blind loops were constructed in separate groups of dogs and the folate coenzymes present in these loops were investigated. Although only those dogs with high blind loops had appreciably elevated folate levels active for Lactobacillus casei but not Streptococcus faecalis, every blind loop appeared to contain four folate compounds--5-formyltetrahydrofolic acid, 5-methyltetrahydrofolic acid, tetrahydrofolic acid and a compound tentatively identified as 5-formyltetrahydrofolic triglutamate. Why increased levels of 5-methyltetrahydrofolate alone are present in the serum of dogs with a high blind loop is discussed.

Animals↗
PubMed1976

Spirometric comparison of carbuterol and isoproterenol aerosol therapy in bronchial asthma. A double blind, matched-pair study of 28 adults and a double blind crossover study of 18 children.

Two adrenergic aerosols were compared in a double blind, matched-pair study of 6 months' duration in 28 adult patients with chronic bronchial asthma, and in a double blind, crossover, short-term study in 18 children with severe asthma. In the adult study, one member of each pair was given either 150 mug of isoproterenol or 200 mug of carbuterol 4 times per day, by inhalation, for 6 months. In the childhood study, 18 children, 6 to 12 years of age, with moderate to severe asthma were studied in a double blind, crossover therapeutic trial in which high or low doses of aerosolized carbuterol or isoproterenol were given 4 times daily for 5 days each. Treatment results were evaluated by measuring forced vital capacity, 1-sec forced expiratory volume, and maximal mid-expiratory flow (FEF25-75%) at regulat intervals before and after administration of the respective test drugs. In the adult study, there was a significant difference between carbuterol and isoproterenol for forced vital capacity (P less than 0.02), for 1-sec forced expiratory volume (P less than 0.02), and for FEF25-75% (P less than 0.01) in favor of carbuterol. In the pediatric study, the difference between carbuterol and isoproterenol was significant (P less than 0.05) only for the FEF25-75% on the fifth day of treatment with the high dose administration of carbuterol. There was no associated toxicity of either drug with respect to electrocardiogram, blood chemistry, or subjective complaints. Tachyphylaxis (tolerance with time) to isoproterenol appeared to develop in one patient.

Adrenergic beta-Agonists↗
PubMed1979

Double-blind and triple-blind assessments of medication and placebo responses in hyperactive children.

Hyperactive boys taking psychostimulant medication were studied using a randomized, placebo-controlled, crossover design. Behavior ratings and medication guesstimates were obtained for the boys when they were given methylphenidate (Ritalin) and when they were given a placebo. The ratings showed positive medication-related changes, and the guesses, done by independent judges, were significantly better than chance. The pattern of ratings for double-blind and triple-blind raters was identical. These results imply that positive psychostimulant effects are not attributable to rater sensitization or expectancy. The medication-placebo differences were highly reliable for the group comparisons and were in the predicted direction for 21 of 22 individuals, but the magnitude of the change for many individuals was not dramatic. Implications for child psychopharmacology research and differences between clinical and experimental significance are discussed.

Child↗
PubMed1977

[How blind is a double-blind trial really? Validity of controlled investigations].

During a double blind trial lasting 4 weeks (Diazepam versus Loxapin), two investigators tried to identify the given drug prematurely. Only the more experienced investigator was able to identify the two drugs (p = 0.01). His judgement was based neither on observation of side-effects nor on a clinical improvement but apparently on a summary of particular subtle effects, the cognition of which requires a specific experience. The use of an adequate comparative drug instead of a placebo in a double blind study does not completely prevent a premature decoding but should reduce this risk and therefore increase the validity of the method.

Anxiety↗
PubMed1976

How double blind is double blind? And does it matter?

In an apparently double blind crossover study, two experienced measurement technicians were able to identify many of the treatment periods. They most often correctly identified aspirin, a drug with prominent effects and side effects. It is argued that in many circumstances it is better to use a blind observer who is not concerned with the giving of treatment or the collection of side effects.

Arthritis, Rheumatoid↗
PubMed1979

Periodontal disease and oral hygiene in a group of blind and sighted Israeli teenagers (14--17 years of age.

The purpose of the present study was to obtain up-to-date information on periodontal disease and oral hygiene status in Israel among 9th to 12th grade non-blind students and among the inmates of six schools for the blind aged 14--17 years. 460 sighted and 434 blind students participated in the study. The examination was for periodontal status and oral hygiene only. Periodontal status was recorded according to Russell's Periodontal Index (PI). Oral hygiene was assessed according to Greene & Vermillion's Simplified Oral Hygiene Index (OHI-S). Mean PI for the non-blind group was found to be 0.23, and for the blind students 0.79. Partially blind students were found to have a lower mean PI value than the totally blind. PI values did not increase significantly with age. Blind students exhibited a fair-to-poor level of oral hygiene (according to Greene & Vermillion's categorization). Relatively healthier levels of oral hygiene were found in the partially blind as compared with the totally blind. Mean OHI-S did not vary with age in either group.

Adolescent↗
PubMed1977

Pathogenesis of mucosal injury in the blind loop syndrome. Brush border enzyme activity and glycoprotein degradation.

The effect of intestinal bacterial over-growth on brush border hydrolases and brush border glycoproteins was studied in nonoperated control rats, control rats with surgically introduced jejunal self-emptying blind loops, and rats with surgically introduced jejunal self-filling blind loops. Data were analyzed from blind loop segments, segments above and below the blind loops, and three corresponding segments in the nonoperated controls. Rats with self-filling blind loops had significantly greater fat excretion than controls and exhibited significantly lower conjugated:free bile salt ratios in all three segments. Maltase, sucrase, and lactase activities were significantly reduced in homogenates and isolated brush borders from the self-filling blind loop, but alkaline phosphatase was not affected. The relative degradation rate of homogenate and brush border glycoproteins was assessed by a double-isotope technique involving the injection of d-[6-(3)H]glucosamine 3 h and d-[U-(14)C]glucosamine 19 h before sacrifice, and recorded as a (3)H:(14)C ratio. The relative degradation rate in both homogenate and brush border fractions was significantly greater in most segments from rats with self-filling blind loops. In the upper and blind loop segments from rats with self-filling blind loops, the (3)H:(14)C ratios were higher in the brush border membrane than in the corresponding homogenates, indicating that the increased rates of degradation primarily involve membrane glycoproteins. Incorporation of d-[6-(3)H]glucosamine by brush border glycoproteins was not reduced in rats with self-filling blind loops, suggesting that glycoprotein synthesis was not affected. Polyacrylamide gel electrophoresis of brush border glycoproteins from the contaminated segments indicated that the large molecular weight glycoproteins, which include many of the surface hydrolases, were degraded most rapidly. Brush border maltase, isolated by immunoprecipitation, had (3)H:(14)C ratios characteristic of the most rapidly degraded glycoproteins. The results indicate that bacteria enhance the destruction of intestinal surface glycoproteins including disaccharidases. Since alkaline phosphatase, a glycoprotein, is not affected, the destruction is selective and presumably involves only the most exposed membrane components.

Animals↗
PubMed2026

Blinding integrity in psychedelic research: Evidence from a comparative randomized controlled trial of psilocybin, MDMA, and methylphenidate in healthy volunteers.

Maintaining effective blinding is a major methodological challenge in psychedelic research. This study provides a comprehensive evaluation of blinding integrity in 120 healthy volunteers who received either psilocybin, MDMA, or methylphenidate (active placebo) in a double-blind, randomized controlled trial. Using a multi-level assessment incorporating forced-choice substance guesses, certainty ratings, decision factors, and subjective substance effects, the analyses characterize blinding integrity and its relation to the substance experience. Results indicate that overall blinding was insufficient, with psilocybin showing the highest rates of functional unblinding, MDMA moderate levels, and methylphenidate the lowest. As an active placebo, methylphenidate provided more effective blinding for MDMA than for psilocybin. Incorporating certainty levels of substance guesses revealed a more differentiated pattern, with lower functional unblinding rates. Decision factors and subjective substance experiences were associated with phenomenological substance effects. Prior substance experiences did not influence accuracy of forced-choice substance guesses. These findings provide empirical guidance for the design and reporting of blinding procedures in psychedelic trials and underscore the value of systematic, multi-level assessment of blinding integrity.

Humans↗
PubMed1979

Structural and functional alterations in the mucosa of self-filling intestinal blind loops in rats.

1. Self-filling blind loops of jejunum were constructed in three groups of rats; in the first, blind loops were created without further manipulation; in the second the bile was diverted permanently into the lower ileum below the blind loop, whereas in a third neomycin was added to the drinking water throughout the experiment. Two weeks after the creation of the blind loops, they were used for structural and functional studies. 2. Morphometric and microdissection techniques demonstrated that the surface area of the individual villi of the mucosa of 'ordinary' blind loops had increased fourfold in comparison with corresponding control jejunum, whereas the increase was only twofold in rats with bile diversion or in the series treated with neomycin. There were proportional increases in crypt length and mitotoic activity of the crypts in all three series, which suggest that the alterations in the mucosa were due to hyperplasia in both villus and crypt compartments. 3. Sucrase, succinate dehydrogenase, alkaline phosphatase and non-specific esterase activities, determined biochemically or histochemically, were reduced in the mucosae of all blind loops, though the changes were most pronounced in the 'ordinary' blind loops. The accumulation of L-phenylalanine by mucosal slices in vitro was depressed, although the decrease was less marked in the series treated with neomycin. 4. These results suggest that both bacteria and deconjugated bile acids play a role in the development of the hyperplastic changes of the blind-loop mucosa, but that another factor might also be involved: as a possible candidate, stasis of the intestinal contents was considered. 5. To test this hypothesis, loops of rat colon were transposed into the jejunum. Above the transposed loop, the jejunal mucosa developed hyperplasia of both villus and crypt compartments, with a reduction in its ability to accumulate L-phenylalanine. It is argued that these changes, probably caused by stasis of the intestinal contents, are triggered off by the dilatation of the gut, which may also be implicated in the mucosal alterations in blind loops.

Alkaline Phosphatase↗