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PubMed1991

Barrett's esophagus: epidemiological and clinical results of a multicentric survey. Gruppo Operativo per lo Studio delle Precancerosi dell'Esofago (GOSPE).

In 1987 we established an Italian multicenter study involving 16 gastroenterologic institutions. The main aims of the study were to assess the prevalence of Barrett's esophagus in a cohort of patients undergoing upper gastrointestinal endoscopy, and the relationship between endoscopic and histologic features. We enrolled 14,898 consecutive patients, and found 251 (1.7%) had endoscopic findings consistent with Barrett's esophagus and/or esophagitis (grade 2 to 4 according to Savary). On histological examination, Barrett's esophagus was confirmed in 111 of 251 patients (44.2%). The crude prevalence rate of BE, based on histology, was 7.4/1,000, and was 2.6-fold higher in males than in females (c.i. 1.7-4.0). Barrett's esophagus proved to be 25-fold more frequent among patients who complained of heartburn (80.1/1,000) than among the others (3.2/1,000). Specialized columnar epithelium was identified in 69 of 111 cases (62.2%) and the proportionate distribution of the histological subtypes was similar in males and in females (chi-square Idf = 0.20, p = n.s.). Dysplasia was detected in 7 patients, all of whom had specialized columnar epithelium (6 low grade and 1 high grade). In conclusion, we believe that our rate of 7.4/1,000 approaches the true prevalence rate of Barrett's esophagus, as it is based on our study of unselected patients presenting for initial evaluation of a variety of UGI symptoms. The occurrence of dysplasia in specialized columnar epithelium suggests that patients with this subtype of Barrett's esophagus may be at increased risk for developing cancer and might, therefore, benefit most from surveillance.

Barrett Esophagus↗

PubMed1991

Familial amyotrophic lateral sclerosis, 1850-1989: a statistical analysis of the world literature.

We present clinical and pathologic data on four previously unreported familial ALS pedigrees and review and analyze by descriptive and exploratory statistical techniques all published cases of familial ALS (1850-1989). In contrast to the age-dependent incidence of sporadic ALS, the age of onset of familial ALS is normally distributed about a mean of 45.7 years (std. dev. 11.3 years). Survival curves for the familial ALS data also demonstrate a skewed distribution with a median survival time of 24 months with 74% surviving at 12 months, 48% at 24 months and 23% surviving at 60 months. The patient characteristics of age at onset of disease, sex and focus of disease onset are unrelated variables and age at onset of disease is the only predictor of survival (Cox's proportional hazard model, chi-square 14.74, p = 0.0001). By applying accelerated failure time models with a log-normal baseline distribution, estimated probabilities for survival adjusted by age at onset were calculated. It was found that the older the age at disease onset, the shorter the survival.

Adult↗

PubMed1976

[Individual variations in the frequency of chromosome aberrations following exposure to chemical mutagens. II. Interindividual variation in the frequency of chromosome aberrations in the presence of different mutagen concentrations].

The object of this investigation was the distribution of human periferal blood cultured obtained from different donors with respect to their sensitivity to different concentrations of thiophosphamide (10, 20 and 30 mcg/ml for 1 hour). Two test characteristics were studied, "the proportion of aberrant metaphases" and "the number of chromosome breaks per 100 cells". It is shown that the distribution of individuals does not depend on the mutagen concentration, being normal in all the series of experiments. The same results were obtained when two different statistical methods were used, viz. the method of four moments and the chi-square test. Since the former method is less labour-consuming, the authors recommend it for fitting the normal distribution in cytogenetic investigations. The variances of the test-characteristics studies ("percent aberrant metaphases" and "total number of breaks per 100 cells") increased with the increase of the mean values. Therefore, before the analysis of variance and the regression analysis the cytogenetic data should be preliminary transformed for the purpose of stabilization of variances.

Chromosome Aberrations↗

PubMed1977

Temporal patterns, their distribution and redundancy in trains of spontaneous neuronal spike intervals of the feline hippocampus studied with a non-parametric technique.

A modification of the non-parametric technique for the analysis of temporal patterns in long trains of single neuronal spike intervals has been described and tested empiracally. The technique is based on inequality testing of sequential pairs of intervals. If the second interval in a pair is longer or shorter than or equal to the first interval, a(+), a(-), and a (0) is recorded respectively in sequential bins of the computer memory. Subsequently, the long sequences of signs are arranged into transition frequency matrices which are then converted into transition probability matrices of various complexity. In this manner, the sign permutations composed of 4, 5, 6, etc. signs were studied. First of all, the theoretical distribution of various sign permutations was derived, assuming that the arrangement of intervals that generate the signs is totally independent. The theoretical distribution of signs permutations in tetragrams, pentagrams and hexagrams constitute the 'controls' with which the empirical data can be compared. In this manner, using the chi-square test, the total deviation of a studied neuronal output from an independent state can be quantified. The empirical data showed a consistent deviation from the theoretical distribution of sign permutations during REM sleep, as compared to slow wave sleep which was characterized by an almost perfect theoretical distribution of sign permutations. This indicates that slow wave sleep is associated with relaxation of constraints that are responsible for the emergence of specific patterns. In addition, redundancies in the occurrence of sign permutations, and the linear relationships between them, have been defined and tested empirically. The apparent discrepancies between the redundancies, based on theoretical symmetry in sign distribution and the linear redundancy that fits the empirical data, have been defined and discussed.

Action Potentials↗

PubMed1979

Perceptions of the school nurse's role.

This study identifies and compares perceptions of school personnel (principals, teachers, counselors and school nurses) about the nurse's role in secondary school settings. A two-art questionnaire was utilized. Part one elicited descriptive data, while part two consisted of 50 Likert-type items related to the school nurse's role. Mean perception scores on the 50 items were obtained by job category and compared using a one-way ANOVA. Chi-square analyses were performed on the frequencies of scale values to determine if their distributions, by item, were the same for all job categories. Correlation coefficients were utilized to determine relationships between training levels, experience, direct contact and perceptions. Analyses revealed: (1) Significant differences in perceptions of the school nurse's role between each group of educators and school nurses. (2) No significant relationship between training level, experience, number of contacts with the nurse and perceptions of the school nurse's role.

Administrative Personnel↗

PubMed2026

Three-Dimensional Fracture Mapping of the Terrible Triad of the Elbow: Morphological Characteristics and Clinical Implications.

BACKGROUND: The morphology of fractures in the terrible triad of the elbow (TTE) is complex, and precise management relies on a profound understanding of this morphology. This study aims to systematically analyze, for the first time, the distribution and morphological characteristics of TTE fracture lines using three-dimensional (3D) imaging technology. METHODS: Clinical data and thin-slice CT scans of 112 patients with TTE from January 2021 to December 2024 were retrospectively included. 3D fracture models were reconstructed using Mimics software. Virtual reduction and standardized alignment were performed using 3-matic software. Fracture lines were mapped onto standard ulnar and radial templates, and 3D fracture heat maps were generated using the E-3D software to demonstrate the high-frequency distribution zones of the fracture lines visually. Statistical analysis was performed using SPSS software (version 21.0, IBM Corp., Armonk, NY, USA). Continuous variables were compared using one-way analysis of variance (ANOVA), and categorical variables were compared using the chi-square test (χ2 test). A two-tailed p < 0.05 was considered statistically significant. RESULTS: The study revealed distinct patterns in the distribution of TTE fracture lines. In the coronoid process, the fracture "hot zone" presented as an annular high-density band extending from the lateral middle aspect to the tip. In the radial head, an oblique high-density band was observed in the anterolateral quadrant of the articular surface. The radial neck exhibited a circumferential high-density zone, which was most prominent in the anterolateral aspect. Statistical analysis indicated a significant correlation between age and fracture complexity; the proportion of Regan-Morrey type III coronoid fractures and Mason type III radial head fractures was significantly higher in elderly patients (> 60 years) (p < 0.05), suggesting that advanced age is a significant risk factor for complex fractures. CONCLUSION: This study is the first to visually reveal the Collaborative Distribution Patterns of TTE fracture lines using 3D fracture mapping technology. This model provides morphological evidence for understanding the injury mechanism of TTE and offers an anatomical framework that may assist surgeons in individualizing surgical approaches and fixation strategies.

Humans↗

PubMed1992

A-type potassium channel clusters revealed using a new statistical analysis of loose patch data.

The spatial distribution of ion channels over the surface of a neuron is an important determinant of its excitable properties. We introduce two measures of channel clustering for use in patch-clamp experiments: a normalized chi-squared statistic (eta) and the number of zero-channel patches in a data set (Z). These statistics were calculated for data sets describing the distribution of A-type potassium channels on neurons of the nudibranch Doriopsilla and measurements of Ca-dependent outward current channels on bullfrog hair cells, as well as simulated channel distributions. When channels are clustered, eta is approximately equal to the amount of current in a cluster. The analysis shows that somatic A-channels in the nudibranch are distributed in clusters of approximately 50 channels each. The clusters are < 2 microns wide and are separated, on average, by 3.2 microns. Outward current channels on hair cells occur in clusters of approximately 27 channels each, in agreement with the original analysis. Channel clustering may reflect properties of the insertion or regulation of channels in the membrane.

Animals↗

PubMed2026

Distinct mutational landscapes for germline and somatic cancer variants in forty tumor suppressor genes.

Germline and somatic cancer variants in tumor suppressor genes (TSGs) share loss-of-function mechanisms, but studies of a few genes (DICER1 and CEBPA) have demonstrated differences in variant consequence and location. To systematically assess whether TSGs display distinct mutational patterns, we leveraged large public genetic databases and compared 32,941 high-quality pathogenic/likely pathogenic (P/LP) germline variants in ClinVar, with 12,907 oncogenic/likely oncogenic (O/LO) somatic tumor variants from cBioPortal across 40 TSGs. Only 3,863 (9.2%) variants were shared. Eighteen TSGs showed significantly different distributions of variant occurrences by molecular consequence, replicated with non-overlapping somatic data from the COSMIC database (chi-squared tests, false discovery rate = 5%). DICER1, TP53, and SMAD4 displayed excess somatic missense events, while nine TSGs (e.g., RB1 and APC) contained excess somatic stop-gain events throughout the coding sequence. Analysis by tumor type revealed excess stop-gain events in tissues exposed to environmental mutagens with corresponding mutation signatures. For several TSGs (WT1), germline variants predispose to tumors (Wilms' tumor) distinct from the majority source of somatic data (myeloid leukemia). Germline and somatic events are also distributed unevenly across cDNA locations, with 103 regions of preferential clustering in 39 TSGs (78 somatic and 25 germline). Twenty somatic clusters contained recurring frameshifts in homopolymer runs, many in tumors with microsatellite instability. Germline clusters contain more germline-exclusive variants, some driving non-cancer phenotypes reflecting genetic pleiotropy. Altogether, germline and somatic variants of TSGs represent unique sets with substantially different patterns shaped by selection pressures from gene-specific and somatic mutational mechanisms. Characterizing these distinctions enables more accurate clinical interpretation of TSG variants.

Humans↗

PubMed1992

Testing the null hypothesis in small area analysis.

The goal of small area analysis is often to demonstrate that hospital admission rates or procedure rates vary greatly among regions, suggesting the occurrence of unnecessary admissions or procedures in some regions. Recent articles have shown that such variation may be largely due to chance, even if no underlying differences exist among the small areas; thus, it is important to test if the observed variation is larger than expected by chance. In this article we discuss how the appropriate method for testing the null hypothesis depends on the distribution of the number of admissions at the person level. If it is not possible for an individual to have more than one admission for a given procedure, the appropriate test is a simple chi-square test. If multiple admissions are possible, a modified chi-square test can be used to account for the excess variability due to multiple admissions. Failure to make the correct modification to the chi-square test in this latter case can result in spurious results. This underscores the importance of collecting data on multiple admissions in order to estimate the distribution of the number of admissions at the individual-patient level.

Analysis of Variance↗

PubMed1977

Caries experience in orthodontically treated individuals.

The caries ecperience in 26 girls and 26 boys living on an island outside. Bergen, who had received orthodontic treatment with fixed appliances, was examined 1.5 to 2 years after the end of treatment. The children were then between 1l and 17 years old. The remaining children of the same age group, 58 girls and 53 boys, served as controls. The orthodontic patients had received repeated hygiene instructions during the treatment period and were expected to rinse their mouth with 0.05% sodium fluoride daily. The percentage distribution of DMF-surfaces indicated somewhat less caries experience in the treated group. A chi-square test showed significantly more intact surfaces on the maxillary first molars, second premolars, canines and central incisors, and mandibular molars and second premolars in treated than in untreated children, and also demonstrated significantly fewer new lesions in the upper second molars at the time of examination in the treated groups. A comparison of the caries experience of the different surfaces revealed significantly more intact surfaces in the treated group and significantly fewer new lesions on the mesial and distal surfaces in treated in untreated children at the time of examination.

Adolescent↗

PubMed1991

Tc-99m HMPAO diffuse pulmonary uptake demonstrated in cigarette smokers.

Tc-99m HMPAO, a lipophilic radiotracer used as a brain SPECT imaging agent in the diagnosis of strokes and dementias, is normally localized in the brain and the heart and is excreted through the kidneys (50%) and the hepatobiliary system (14% to 30%). There is no pulmonary localization except in the lungs of smokers. To evaluate pulmonary localization of Tc-99m HMPAO in relation to smoking, 23 patients (aged 27 to 76 years) who were referred for brain imaging studies for strokes or dementias also underwent lung imaging studies immediately following the brain imaging. Anterior and/or posterior lung images were obtained 30 to 45 minutes after IV injection of 15 mCi Tc-99m HMPAO. Diffuse pulmonary uptake was graded semiquantitatively: 3+, pulmonary uptake is equal to or higher than hepatic uptake; 2+, pulmonary uptake is less than hepatic uptake but higher than cardiac uptake; 1+, pulmonary uptake is equal to cardiac uptake; 0, pulmonary uptake is less than cardiac uptake. Each patient's smoking history, including duration and daily consumption, was recorded. Four patients' lung images showed 3+ lung uptake; 6 patients, 2+; 1 patient, 1+; and 12 patients, 0 uptake. Eleven patients with lung uptakes of 3+ to 1+ had a history of cigarette smoking. Twelve patients with lung uptake less than cardiac uptake had no smoking history. Pulmonary distribution of Tc-99m HMPAO is usually negligible in the normal lung. Our results indicate that lung uptake correlates significantly (chi-square = 23, d.f. = 1, P = 0.0001) with smoking history.

Adult↗

PubMed1978

Use of the beta-binomial distribution in dominant-lethal testing for "weak mutagenic activity: part 2.

Experiments in Dominant-Lethal Testing have been simulated on the computer to estimate the type I error rates and the power of the Beta-Binomial test under various models. (1) The mating ratio is one; and p, the probability that an implant will die, is distributed over the couples. (2) The mating ratio is larger than one; and p is distributed over the males, the females mated to the same male being binomial observations of the value p supplied by the male. (3) The mating ratio is larger than one; and p is distributed over the females. The average rates of dead implants have been set at 0.08 and 0.10 for the control and treatment groups, respectively, and a nominal level of significance equal to 0.05 has been chosen. The type I error rate of the traditional chi-square test has also been estimated. A by-product of these simulations is the behaviour of the estimates alpha and beta of the beta-distribution parameters, which discloses that, in the actual experiments with mice, p is distributed over the females. Our results lead to the recommendations that, for a given number of animals per group, a mating ratio larger than one should be adopted and that the males should be considered as the experimental units for the calculations. With 300 and 450 animals per group, average powers of 0.72 and 0.85 are reached, respectively, for the chosen increment of 2% in the rate of dead implants. Under these models, the type I error rate of the traditional chi-square test may grow to 0.30 for the nominal level of 0.05.

Genes, Dominant↗

PubMedDate not supplied

Dipyridamole thallium-201 scintigraphy in patients with arteriosclerosis obliterans. Increased accuracy in identifying cardiac risk.

Forty-eight preselected patients (pts) with arteriosclerosis obliterans were investigated by dipyridamole thallium scintigraphy (DTS). No correlation was found between the distribution of positive or negative exercise ECG testing (ExECG) and isotopic risk-scores (P > 0.1 in the chi-square test). We assessed cardiac ischaemia in 12 pts with insufficient ExECG. Although only 2 pts had documented previous myocardial infarction, 20 pts exhibited irreversible perfusion defect. Silent reversible or irreversible ischaemia was identified in 12 pts (25%). Seven pts would not have been diagnosed to have coronary artery disease (CAD) even by ExECG. In conclusion, DTS was found very useful in these cases. We support a stepwise cardiac risk stratification before major vascular surgery.

Adult↗

PubMed1979

Influence of a between-run component of variation, choice of control limits, and shape of error distribution on the performance characteristics of rules for internal quality control.

A computer-stimulation study has been performed to determine how the performance characteristics of quality-control rules are affected by the presence of a between-run component of variation, the choice of control limits (calculated from within-run vs. total standard deviations), and the shape of the error distribution. When a between-run standard deviation (Sb) exists and control limits are calculated from the total standard deviation (St, which includes Sb as well as the within-run standard deviation, Sw), there is generally a loss in ability to detect analytical disturbances or errors. With control limits calculated from Sw, there is generally an increase in the level of false rejections. The presence of non-gaussian error distribution appears to have considerably less effect. It can be recommended that random error be controlled by use of a chi-square or range-control rule, with control limits calculated from Sw. Optimal control of systematic errors is difficult when Sb exists. An effort should be made to reduce Sb, and this will lead to increased ability to detect analytical errors. When Sb is tolerated or accepted as part of the baseline state of operation for the analytical method, then further increases in the number of control observations will be necessary to achieve a given probability for error detection.

Chemistry, Clinical↗

PubMed1977

Is there an association between astrological data and personality?

A test was made of the hypothesis that personality characteristics can be predicted on the basis of various features of the individual's astrological chart. Astrological charts were prepared for 196 college-age Ss who also were administered the MMPI and the Leary Interpersonal Check List. Ss were divided into those who had extreme scores on any of the 13 personality variables studied and those who did not. For each personality variable, comparisons were made on a large number of astrological dimensions between distributions of Ss with and without extreme test scores. Six hundred thirty-two such comparisons were made and evaluated with chi-square tests. In that the obtained number of statistically significnat chi-squares was less than what would be expected on a chance basis, the hypothesis was rejected.

Astrology↗

PubMed1977

Evaluation of the non-randomness of protein compositions.

A method is described for assessing the non-randomness of protein compositions, based on the chi-squared statistic for the differences between the observed numbers of residues of each type and the numbers expected for a random distribution of codons. The analysis indicates that changes in at least 30% of the residues in natural proteins are selected against.

Amino Acids↗

PubMed1979

Birth order and parental age in microphthalmos and other ocular diseases.

We compared the distribution of birth order and maternal and paternal ages of blind school children throughout Japan with that of the total Japanese population of the corresponding age groups and with that of a subgroup of children with acquired blindness. The number of first-born children with microphthalmos was smaller, and the number of second-, third-, or fourth-born children was larger, as compared with the control groups. The differences were highly statistically significant by chi-square test. There was a less pronounced indication of birth order effect in amblyopia, congenital cataract, and optic nerve atrophy, which involved more first-borns than in the controls. The distribution of maternal age was also different from the control group in microphthalmos, congenital cataract, corneal opacity, and optic nerve atrophy. Less mothers in their 20s and more in their 30s produced children with these conditions. We believe this finding may be partly related to the rapid decline in infant mortality and in the incidence of congenital blindness in Japan.

Adult↗

PubMed1991

Genetic epidemiology of non-insulin-dependent diabetes mellitus in north India: preliminary analyses of some genetic markers in Punjabis.

Studies on monozygotic (MZ) twins and admixed populations show that the predisposition to non-insulin-dependent diabetes mellitus has a large genetic component. We have examined the distribution of some genetic polymorphisms (ABO, GLO, ESD, AK, ACPA, and GPI) in control and diabetic Punjabis from north India. The distribution of various genetic markers indicate that the differences between the control and diabetic samples are statistically not significant. Moreover, a contingency chi-square analysis over all loci suggests nonsignificant genetic differentiation (p = 0.50) between the Punjabi samples.

Adult↗