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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↗
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↗
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↗
PubMed2026

Assessment of blinding in pharmacotherapy and noninvasive neuromodulation randomized controlled trials for neuropathic pain in adults.

In randomized controlled trials (RCTs), study participants and research personnel are often blinded to minimize biases related to knowing treatment allocation. To determine if blinding was effective, participants may be asked which treatment they believe they received ("treatment guess"). This descriptive review characterized blinding assessment (BA) reporting in pharmacotherapy and neuromodulation neuropathic pain RCTs. Of 288 papers, 36 (12.5%) reported a BA. One paper reported the results of 2 studies, so in total 37 studies with a BA were assessed. Of these, 19 were crossover, 17 parallel, and 1 partial crossover in design. All 37 studies assessed participant blinding, and 10 also assessed investigator blinding. Approximately 27% included an "unsure" answer option for treatment guess, and 38% asked the reason for the guess. There were no clear patterns in BA reporting across time nor based on treatment type. Seventeen trials provided sufficient data to calculate Bang Blinding Index (BI) to determine blinding success. Participants remained blinded (BI = 0 &#xb1; 0.2) in 10/17 placebo and 10/17 treatment arms, 6 placebo and 5 treatment arms had a BI > 0.2 suggesting possible unblinding, whereas 1 placebo and 2 treatment arms had a BI < -0.2 suggesting misinformed guessing. Overall, we found that BAs are done in a minority of published neuropathic pain trials and with variable methodology. Given the importance of minimizing risk of bias because of treatment unblinding, future studies should consider including BAs, and further consensus building is necessary to determine if and how BAs should be conducted and interpreted in analgesic clinical trials.

Bias↗
PubMed1979

Some causes of blindness seen at Noor Eye Institute, Afghanistan.

This is a survey of the causes of blindness recorded by three students of The City University during a six-week stay at NOOR Eye Institute in Kabul, Afghanistan. The nature of the sample used makes it unsuitable for direct comparison with surveys from other countries. Nevertheless, broad conclusions can be drawn. Severe eye disease is a considerable problem in Afghanistan, in common with other developing countries. The survey included all new patients seen in the outpatient clinic, blind to the extent of being unable to count fingers at more than three metres, in one eye or both. The sample of patients was examined by an ophthalmologist working with our team. A diagnosis was made and various social and demographic questions were asked with the help of an interpreter. In all, 473 patients were examined and included in our survey sample, a very high proportion of the new patients attending the clinic (40.46 per cent). The main causes of blindness were found to be cataract (31.12 per cent), corneal scarring (19.8 per cent), chorioretinal degenerations (6.79 per cent), glaucoma (6.65 per cent) and aphakia (5.52 per cent). Of the major causes of blindness, about forty per cent of the cases were considered remediable, and about thirty per cent could have been prevented. An outstanding difference between the causes of blindness in developed nations and those seen in Afghanistan was the amount of blindness caused by infection, especially in the younger age groups (up to 30 years). Cataract is a major cause of blindness in the older age groups of both societies. People suffering from ocular disease in Afghanistan wait until their sight is badly impaired or lost completely before seeking treatment. This results from a lack of knowledge of what could be done to conserve sight, the irreversible nature of many eye diseases, the distances involved in travelling to the clinic, and even a lack of knowledge of its existence.

Adolescent↗
PubMed2026

Redefining the real problem in psychedelic trials: Why fighting the Lessebo matters more than blinding integrity.

Imperfect blinding is not specific to psychedelic trials. In randomized trials, treatment allocation is frequently correctly guessed, yet blinding integrity is rarely assessed outside of psychedelic research and is generally not considered a barrier in regulatory evaluation. The intense debate in psychedelics may reflect a broader double standard affecting mental health research, when uncertainties arising from imperfect blinding are confounded by those linked to patient-reported outcome measures. Indeed, people living with mental disorders are often viewed as unreliable reporters, despite well-documented limitations of clinician-rated scales and the absence of robust biological markers of symptomatic change. Importantly, it is the maintenance of reasonable doubt of treatment allocation that sustains internal validity and ethical feasibility of placebo-controlled designs, rather than perfect blinding. Concerns about expectancy bias in psychedelic trials are closely tied to blinding debates. When allocation is inferred, expectations may cluster in the arm perceived as active or in stereotyped experiences and influence outcomes differently in active and control arms, leading to a risk of lessebo, a negative placebo effect due to the negative expectation related to receiving a placebo. However, we argue that an underrecognized mechanism of lessebo is disappointment. This risk may reflect insufficient clinical management of disappointment rather than pre-treatment expectation alone. We therefore propose shifting the emphasis from preserving inevitably imperfect blinding towards mitigating disappointment in both arms. Establishing non-stereotyped expectations prior to treatment through structured psychoeducation, strengthened therapeutic alliance, and realistic preparation would help avoid lessebo effects. Such strategies would enhance ethical rigor, interpretability, and the clinical usefulness of psychedelic trials.

Humans↗
PubMed1979

Protein digestion and absorption in the blind loop syndrome.

Protein digestion and absorption was studied in rats with 6-week-old surgically constructed self-filling intestinal blind loops and steatorrhea, ie, blind-loop animals and controls were fed a 14C-labeled protein meal containing a nonabsorbable marker, 51CrCl3, and sacrificed 1 or 2 hr later. Intestinal contents were analyzed for 14C, 51Cr, protein, trypsin, and the products of digestion. At 1 hr, 14C absorption was greater in controls, but at 2 hr there was no difference in absorption between the two groups. Marker studies showed that blind-loop filling resulted in a delay of the progression of intestinal contents distally. Intraluminal trypsin and porteolysis were similar in the two groups. Endogenous protein was greater in the blind-loop animals. The early stages of the blind-loop syndrome may be characterized by delayed protein absorption secondary to blind-loop filling, which is compensated for by the distal gut resulting in an absence of overall protein malabsorption.

Animals↗