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At least 649 records · Page 36Linked to original sources
PubMed2006

The role of endogenous growth hormone-releasing hormone in acromegaly.

CONTEXT: Some indirect evidence suggests hypothalamic control of GH secretion in acromegaly. OBJECTIVE: The objective of the study is to examine whether GH secretion in acromegaly is dependent on endogenous GHRH. PATIENTS AND STUDY DESIGN: We studied eight patients with untreated acromegaly due to a GH-producing pituitary tumor. All patients received an iv infusion of normal saline for 24 h and GHRH-antagonist (GHRH-ant) at 50 microg/kg x h for 7 d. GH was measured every 10 min for 24 h during the normal saline infusion and on the last day of the GHRH-ant infusion. A group of nine different patients with untreated acromegaly served as the control group and underwent blood sampling for GH every 10 min for two 24-h periods to assess the day-to-day variability of GH secretion. SETTING: The study was set in a university referral center. MAIN OUTCOME MEASURE: Twenty-four-hour mean GH was the main outcome measured. RESULTS: In six of eight subjects treated with GHRH-ant, 24-h mean GH decreased by 5.8-30.0% during iv GHRH-ant and, in three subjects, the change in the 24-h mean GH was greater than the upper limit of the 95% confidence interval of the spontaneous day-to-day variability of the mean GH in patients with acromegaly. Based on the binomial distribution, the probability of this magnitude of change to occur in three of eight subjects by chance alone is 0.0008. CONCLUSION: In some patients with acromegaly due to a pituitary adenoma, GH secretion is under partial control by endogenous GHRH.

Acromegaly↗
PubMed2003

Neuropsychological functioning after surgery in children treated for brain tumor.

OBJECTIVE: To describe the neuropsychological functioning of children treated with surgery only for localized brain tumors in Dana-Farber Cancer Institute Protocol 92-077. Subsequent reports will describe the neuropsychological functioning of children treated with surgery and stereotactic radiation therapy on Dana-Farber Cancer Institute 92-077. METHODS: The intellectual functioning of 106 patients was evaluated within 3 months after surgery. An in-depth assessment of the neuropsychological functioning, including an impairment index, was conducted for a subset of 77 school-age children (6-16 yr old) across six functional domains. Descriptive statistics were generated; binomial distribution analyses were performed to assess whether the proportion of individuals with impaired performance on each measure exceeded normative expectations. The impairment index assessed whether poor performance was attributable to a few children or reflected the performance of the cohort as a whole. RESULTS: Although the Full Scale IQ was within normative expectations, the Verbal IQ was higher than the Performance IQ with 45% of individuals showing a significant discrepancy (P < 0.01) between these scales. There was an increased prevalence of poor performance for measures of motor output, verbal memory, and visuospatial organization. The distribution of the impairment index indicated moderate impairment across the school-age cohort rather than severe impairment in a few patients. CONCLUSION: The results document a moderate level of neuropsychological morbidity among children with brain tumors before stereotactic radiation therapy, presumably referable to the tumor itself and the surgery. The extent to which stereotactic radiation therapy may increase this burden will be assessed in follow-up studies evaluating the longitudinal neuropsychological data.

Adolescent↗
PubMed1984

Stochastic partitioning of chloroplasts at cell division in the alga Olisthodiscus, and compensating control of chloroplast replication.

We asked how chloroplasts in a unicellular marine alga are replicated and partitioned at cell division so that each daughter cell will receive the appropriate number of copies. The data were obtained simply by counting chloroplasts in pairs of daughter cells immediately after cell division. The results show that chloroplast partitioning is not always equal; however, it is equal much more often than predicted by the binomial distribution of chloroplast numbers that would be expected if partitioning were strictly random. The parental chloroplasts were partitioned equally in approximately 76% of the divisions, while in the remaining 24% the deviations from equality were very small. To maintain a reasonable range of chloroplast numbers in the face of unequal partitioning, there must be some form of compensating control of chloroplast replication. Our data suggest that daughter cells that receive very large numbers of chloroplasts go directly to the next division without replicating their chloroplasts, while cells with very small numbers of chloroplasts go through two rounds of chloroplast replication before dividing.

Cell Division↗
PubMed1985

Use of historical controls for animal experiments.

Statistical methods for the use of historical control data in testing for a trend in proportions in carcinogenicity rodent bioassays are reviewed. Asymptotic properties of the Hoel-Yanagawa exact conditional tests are developed and compared with the Tarone test. It is indicated that the Hoel-Yanagawa test is more powerful than the Tarone test. These tests depend on the beta-binomial parameters which are estimated from historical data. The goodness of fit of beta-binomial distributions to historical data is illustrated by application to the historical control database in the National Toxicology Program. Finally, sensitivities of the exact conditional test to the historical information is discussed and a conservative use of the test is considered.

Animals↗
PubMed1994

Statistical methods for the beta-binomial model in teratology.

The beta-binomial model is widely used for analyzing teratological data involving littermates. Recent developments in statistical analyses of teratological data are briefly reviewed with emphasis on the model. For statistical inference of the parameters in the beta-binomial distribution, separation of the likelihood introduces an likelihood inference. This leads to reducing biases of estimators and also to improving accuracy of empirical significance levels of tests. Separate inference of the parameters can be conducted in a unified way.

Animals↗
PubMed2004

Patient-reported outcome in total hip replacement. A comparison of five instruments of health status.

Our aim was to define the minimum set of patient-reported outcome measures which are required to assess health status after total hip replacement (THR). In 114 patients, we compared the pre-operative characteristics and sensitivity to change of the Oxford hip score (OHS), the Western Ontario and McMaster Universities osteoarthritis index (WOMAC), the SF-36, the SF-12 (derived from the SF-36), and the Euroqol questionnaire (EQ-5D). At one year after operation, very large effect sizes were found for the disease-specific measures, the physical domains of the SF-12, SF-36 and the EQ-5Dindex (1.3 to 3.0). Patients in Charnley class A showed more change in the OHS, WOMAC pain and function, the physical domains of the SF-36 and the EQ-5Dvas (p < 0.05) compared with those in the Charnley B and C group. In this group, the effect size for the OHS more than doubled the effect sizes of WOMAC pain and physical function. We found high correlations and correlations of change between the OHS, the WOMAC, the physical domains of the SF-12 and the SF-36 and EQ-5Dindex. The SF-36 and EQ-5D scores at one year after operation approached those of the general population. Furthermore, we found a binomial distribution of the pre-operative EQ-5Dindex score and a pre-operative discrepancy and post-operative agreement between the EQ-5Dvas and EQ-5Dindex. We recommend the use of the OHS and SF-12 in the assessment of THR. The SF-36 may be used in circumstances when smaller changes in health status are investigated, for example in the follow-up of THR. The EQ-5D is useful in situations in which utility values are needed in order to calculate cost-effectiveness or quality-adjusted life years (QALYs), such as in the assessment of new techniques in THR.

Aged↗
PubMed1978

A photographic method for the measurement of motility of bull spermatozoa.

Bull spermatozoa were diluted in skim milk-egg yolk and frozen. After thawing, the samples were added to citrate buffer and photographed (1 sec exposure, 400 ASA, dark field) to identify the tracks of the moving spermatozoa. The proportions of motile spermatozoa in 1707 photographs of semen samples from 25 ejaculates were distributed binomially, and allowed motility to be estimated at a predictable level of precision, and without bias when one photograph from each of two straws was taken at random from an ejaculate. The variance was equal to its expectation and inversely proportional to the total number of spermatozoa in each photographic field.

Analysis of Variance↗
PubMed1987

A study of additional forms of the human sperm lactate dehydrogenase isoenzyme.

Unusual isoenzymes of the sperm-specific lactate dehydrogenase detected in the seminal plasma of some infertile men were investigated using selective precipitation by antisera followed by electrophoretic resolution. The presence of two C subunit types was established: type I is a polymer of the four common C-subunits and type II consists of four C-subunits. Subunits of types I and II combine to form 5 sperm-specific binomially distributed lactate dehydrogenase isoenzymes. These results suggest the existence of two alleles at the c locus.

Electrophoresis, Polyacrylamide Gel↗
PubMed2002

Decreased morning serum cortisol levels in children with asthma treated with inhaled fluticasone propionate.

OBJECTIVE: In an observational long-term study, we followed 62 children (37 males, 25 females; mean age: 11.6 +/- 2.9 years) with moderate-to-severe asthma for 2 years and studied the effects of fluticasone propionate (176-1320 microg/day) on the function of the hypothalamic-pituitary-adrenal axis. STUDY DESIGN: Morning cortisol levels were monitored after patients had been on fluticasone for a mean of 8.0 +/- 5.2 months. Patients who had abnormal low morning cortisol levels (<5.5 microg/dL) were then switched either to lower fluticasone dosage or to other inhaled steroid formulation. Exact methods based on the binomial distribution were used to construct a 95% confidence interval for the true proportion of abnormal readings among those treated, and the Wilcoxon signed rank test was used to test for a significant difference between cortisol levels taken before and after the switch. RESULTS: Twenty-two patients (36%) had abnormal morning cortisol levels while on fluticasone. Of the patients on a low dose (176 microg/day), 17% had abnormal values, whereas 43% of patients on a high dose (> or =880 microg/day) were abnormal. Patients with abnormal results (17/22) had their morning cortisol levels repeated 3 months after the switch. Thirteen of these patients (77%) had normal levels. A stratified analysis of the difference in morning cortisol levels before and after the switch showed significant increase in morning cortisol levels in the group receiving 440 microg/day or less of fluticasone (median difference: 5.25; confidence interval: 3.60-8.15), as well as in the group receiving 440 microg/day or more (median difference: 3.85; confidence interval: 1.00-7.60). CONCLUSION: Inhaled fluticasone, even at conventional doses, may have greater effects on the adrenal function than previously recognized, but the clinical significance of this suppression still remains to be established.

Administration, Inhalation↗
PubMedDate not supplied

[Hepatitis B case grouping serological study among six chinese families in Almeria, Spain].

BACKGROUND: Following the detection of two cases of members of 6 Chinese families having tested positive for the hepatitis B virus, a study of those living in these families was begun for the purpose of knowing the spread of the infection within the family environment of the cases detected. METHODS: Descriptive study. Population under study: 24 members of six Chinese families. VARIABLES: Age, sex, serological diagnosis, risk factors, healthcare-related attitude. INFORMATION SOURCES: Clinical records, serological data, epidemiological survey and immunization cards. A family focus was employed and the genogram used. DATA ANALYSIS: Distribution Binomial spread for calculating probability of occurrence of the process to be studied. RESULTS: A total of 14 males (58.3%) and 10 females (41.7%) ranking from 1 to 54 years of age were studied. The age group having the largest number of subjects studied was the age 21-30 group (37.5%). Twelve chronic hepatitis B infections were recorded (50%). No relationship was found to exist with the risk factors studied in the epidemiological survey conducted. The probability of this number of chronic hepatitis cases occurring was 0.066 x 10(-6). CONCLUSIONS: It was concluded that the prevalence of infection found was probable due to intra-family transmission. Given the low probability of occurrence of a process of this type, the case grouping found is considered to be high.

Adolescent↗
PubMed2000

Evaluation of sequential sampling plans for the larger grain borer (Coleoptera: Bostrichidae) and the maize weevil (Coleoptera: Curculionidae) and of visual grain assessment in West Africa.

Repeated sampling of rural maize stores in Benin was conducted to evaluate published parameters of a sequential sampling plan for a negative binomial distribution to determine pest status for Prostephanus truncatus (Horn) and Sitophilus zeamais Motschulsky. A computer program was used to rerandomize the data and evaluate the effects, in terms of average sample number and error rates, of different sampling plan parameter values. With respect to P. truncatus, lower and upper thresholds of 0.2 and 1.0 insects per ear and parameter values of k = 0.2 and alpha = beta = 0.1 were found to be adequate. With respect to S. zeamais, lower and upper thresholds of 10 and 20 insects per ear and parameter values of k = 1.0 and i alpha = beta = 0.1 were found to be adequate. Simplified sampling rules were proposed in which 11 ears should be sampled and if no P. truncatus are found, the population is low; otherwise the Wald plan should be followed. Owing to the lower per capita rate of damage, effective simplified sampling rules for S. zeamais were difficult to construct. An evaluation of the visual assessment scale rising whole ears showed that a visual scale estimating percentage damage rather than percentage loss, might be easy to construct and preferable for traders. Further work is needed to improve the usefulness of the visual scale in pest management decision support.

Animals↗
PubMed2004

Boll weevil (Coleoptera: Curculionidae) survival through the seed cotton cleaning process in the cotton gin.

There is concern that gins located in boll weevil, Anthonomus grandis grandis Boheman, eradication zones may become points of reintroduction when they process cotton grown in a neighboring infested area. We estimated boll weevil survival through two typical machine sequences used in commercial cotton gins to clean and dry the seed cotton in advance of the gin stand, as well as separately through two incline cylinder cleaners or one or two tower dryers operating at different temperatures. Large numbers of laboratory-reared adult boll weevils were marked with fluorescent powder, fed into the test system, and recovered with the assistance of blacklights. We found no evidence of survival through the seed cotton cleaning systems even when the dryers were not heated, or when passed separately through the two incline cleaners alone. Upper confidence limits (95%) were calculated for the observed zero recoveries based on sample size and the binomial distribution, and these represent the statistical worst-case (i.e., highest) survival potential. Survival through heated tower dryers declined rapidly to zero at higher temperatures, especially when two dryers were running. Although we conclude that the potential for survival of weevils in the seed cotton to the gin stand is zero or close to zero, a small percentage of live weevils was recovered in the green boll/rock trap, which may represent the greatest threat of reintroduction at the gin. Escape of live weevils with the gin trash is also possible, and studies addressing this issue will be presented elsewhere.

Agriculture↗
PubMed1979

Decision rules and signal detectability in a reinforcement-density discrimination.

Two probabilistic schedules of reinforcement, one richer in reinforcement, the other leaner, were overlapping stimuli to be discriminated in a choice situation. One of two schedules was in effect for 12 seconds. Then, during a 6-second choice period, the first left-key peck was reinforced if the richer schedule had been in effect, and the first right-key peck was reinforced if the leaner schedule had been in effect. The two schedule stimuli may be viewed as two binomial distributions of the number of reinforcement opportunities. Each schedule yielded different frequencies of 16 substimuli. Each substimulus had a particular type of outcome pattern for the 12 seconds during which a schedule was in effect, and consisted of four consecutive light-cued 3-second T-cycles, each having 0 or 1 reinforced center-key pecks. Substimuli therefore contained 0 to 4 reinforcers. On any 3-second cycle, the first center-key peck darkened that key and was reinforced with probability .75 or .25 in the richer or leaner schedules, respectively. In terms of the theory of signal detection, detectability neared the maximum possible d' for all four pigeons. Left-key peck probability increased when number of reinforcers in a substimulus increased, when these occurred closer to choice, or when pellets were larger for correct left-key pecks than for correct right-key pecks. Averaged over different temporal patterns of reinforcement in a substimulus, substimuli with the same number of reinforcers produced choice probabilities that matched relative expected payoff rather than maximized one alternative.

Journal Article↗
PubMed1983

Current sickle cell screening program for newborns in New York City, 1979-1980.

The newborn screening program mandated by the New York State Public Health Law requires that every baby born in the state be tested for eight conditions including sickle cell anemia. Although sickle cell screening of newborns has been in operation since 1975, the follow-up program for case retrieval to obtain repeat blood samples for definitive diagnosis and referral of diagnosed patients for ongoing medical care was established only in 1979. Of the 106,565 blood samples tested in New York City Newborn Screening Laboratory, March 1, 1979 to February 29, 1980, 141 infants were identified on repeat blood testing as having various forms of sickle cell disease (SS, SC and S beta-Thalassemia) and were referred for ongoing medical care. Data received on 131 patients from follow-up clinics revealed that the disease diagnosis made by the Newborn Screening Laboratory was confirmed in all patients. There were no deaths reported among the study patients (131 infants) followed for the period of 8-20 months despite the life-threatening complications among eight patients. Binomial distribution of the data on Black infants according to the Hardy-Weinberg equation showed reasonable agreement between the observed and computed incidence of various forms of sickle cell disease.

Anemia, Sickle Cell↗
PubMed2006

Improved cancer detection using computer-aided detection with diagnostic and screening mammography: prospective study of 104 cancers.

OBJECTIVE: This study prospectively evaluated a computer-aided detection (CAD) device used with diagnostic and screening mammography by assessing cancers detected; tumor sizes, histology, and stage; positive predictive value (PPV) of biopsy recommendation; and recall rates before and after CAD introduction. SUBJECTS AND METHODS: Interpretations of 9,520 consecutive mammograms were recorded without and then with CAD for a 28-month period. Cancer detections based on initial radiologist review and additional detections based on CAD findings were noted. Recall rates, tumor size and histology, and PPV of biopsy recommendation before and after the introduction of CAD were compared. RESULTS: Cancers detected only with CAD assistance were 9.6% of all cancers (10 of 104); screening-detected cancers increased 13.3% with CAD assistance (four in addition to 30 screening-detected cancers). The 95% one-sided confidence boundary using binomial distribution is consistent with at least 5.3% for all cancers and 5.1% for nonpalpable cancers. The greatest impact was on ductal carcinoma in situ, for which CAD increased cancer detection by 14.2% (three added to 21). Similar percentages of cancers were detected only with CAD assistance in both screening (11.4%; 4 of 35) and diagnostic (9.5%; six of 63) studies. Additional cancers were detected using CAD in patients with implants and previous lumpectomy. The additional cancers detected with CAD were smaller (p = 0.01 for all cancers, p = 0.03 for nonpalpable invasive cancer). The screening recall rate increased from 6.2% to 7.8% after CAD, with a decrease in the biopsy rate and a nonsignificant increase in the biopsy PPV from 21.9% to 26.3%. CONCLUSION: CAD resulted in detection of more cancers in screening and diagnostic patients, with an increased recall rate but no deterioration in PPV of biopsy. Additional cancers detected were significantly smaller.

Biopsy↗
PubMed1983

Two methods for teachers' measurement of impulse control.

Offering students immediate versus delayed reward choices is a well known method of measuring delay of gratification used by Mischel. In offering students a set of such choices the classroom teacher may question where to place the cut-off scores separating delay from non-delay. This dilemma is resolved by use of probabilities produced by a binomial distribution for a given set of scores. The probabilities will show the number of choices required for a student to be identified as delaying beyond chance. Some teachers may decide to substitute the estimation of a 60-sec. interval for the classic delayed reward task. This substitution was suggested by Spivack, Levine, and Sprigle in 1959 and confirmed by subsequent work.

Choice Behavior↗
PubMed2001

Nonasymptotic significance tests for two measures of agreement.

The kappa agreement coefficient of Cohen from 1960 and Brennan and Prediger from 1981 are defined and compared. A FORTRAN program is described that computes Cohen's kappa and Brennan and Prediger's kappa and their associated probability values based on Monte Carlo resampling and the binomial distribution, respectively.

Algorithms↗