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Biomedical subjects

N G Berman

Publications and source records attributed to N G Berman.

17 recordsLinked to original sources
PubMed2003

A double application approach to ophthalmia neonatorum prophylaxis.

AIMS: To investigate if a second drop of 2.5% povidone-iodine ophthalmic solution placed within the first postnatal day would achieve better prophylaxis against ophthalmia neonatorum than a single drop applied at birth. METHODS: A masked, prospective, controlled trial was conducted over a 2 year period in a Kenyan hospital. Randomisation was achieved by alternating weeks of one or two eye drop application to both eyes. All 719 neonates received one drop of the povidone-iodine solution to both eyes at birth, while 317 received a second drop at hospital discharge or 24 (SD 4) hours after delivery, whichever was first. All infants developing conjunctivitis within a month after birth underwent microbiological analysis using Gram and Giemsa stains, direct fluorescent antibody assay for Chlamydia trachomatis, and culture. RESULTS: Of the neonates receiving the one eye drop application, 18.4% returned with a red eye with discharge, 4.0% had organisms found on the initial smear, and 8.2% had a positive culture. The corresponding proportions for the multidrop group were 24.3%, 4.7%, and 10.4%. Of those returning with an inflamed eye, there were no cases of Neisseria gonorrhoeae, 4.2% in the single dose group and 3.9% in the double dose group were positive for C trachomatis, and 5.4% and 6.5% respectively for Staphylococcus aureus. At discharge, the eyelid oedema score of the double dose group was mildly greater than the single dose group (1.4 (0.67) v 1.2 (0.73), p=0.0002). There was no statistically significant difference between the groups in any other category. CONCLUSION: There is no advantage to administering povidone-iodine prophylaxis against ophthalmia neonatorum twice in the first postnatal day over a single application at birth.

Anti-Infective Agents, Local↗
PubMed2000

Validation of a new technique to detect malingering of cognitive symptoms: the b Test.

We administered the b Test, a new measure to identify malingering requiring recognition of overlearned information, to 34 suspected malingerers and to 161 subjects in various clinical groups (moderate to severe head injury, elderly depressed, learning disability, schizophrenia, right and left CVA, and elderly normals). Comparisons of groups revealed more commission and omission errors in the suspected malingerers relative to all groups except the right stroke patients. In addition, suspected malingerers took longer to complete the task than all groups except right and left stroke patients and normal elderly. A cutoff of >2 commission errors produced a sensitivity of 76.5% and specificity for all comparison groups combined of 82.6%. Lower sensitivity rates were documented for omissions (58.8 using cutoff of >40) and time (57.6% using cutoff of >12 minutes), but specificity remained high at 85.1% and 83.9%, respectively. Thus, the b Test shows considerable potential as a malingering detection tool.

Journal Article↗
PubMed1999

Psychomotor performance and monoamine function in bipolar and unipolar affective disorders.

BACKGROUND: Affective disorders are associated with prominent psychomotor abnormalities that may be related to changes in arousal or motivation due to altered catecholamine function. METHODS: We investigated relationships between performance on psychomotor tests of motor speed (reaction time and tapping speed) and visual tracking (trail making and dot placement) and catecholamine system function including cerebrospinal fluid (CSF) or urinary concentrations of catecholamines or their metabolites. Subjects were medicine-free inpatients with unipolar depression or with manic, depressive, or mixed episodes of bipolar disorder, and healthy controls matched by gender and stratified by age. RESULTS: Unipolar and bipolar depressed patients were impaired in motor speed, dexterity, and visual tracking, whereas manic and mixed patients did not differ from controls. Tapping speed correlated positively with CSF 3-methoxy-4-hydroxyphenylglycol in healthy controls and with CSF homovanillic acid in bipolar depressed subjects. Increased catecholamine function correlated with slowing in all other measures for patients with bipolar disorder. Relationships between catecholamines and psychomotor function were weaker in unipolar depressed subjects. Psychomotor function was related to severity of depression in bipolar, but not in unipolar, patients. CONCLUSIONS: These data suggest that catecholamine systems are associated with increased arousal and psychomotor impairment in patients with bipolar disorder. Similar behavioral changes have different neurotransmitter relationships in unipolar disorder.

Adult↗
PubMed1998

Criteria for authorship for statisticians in medical papers.

We organize a statistician's potential scientific and intellectual contributions to a medical study into three types of activities relating to design, implementation and analysis. For each type, we describe high-level, mid-level and low-level contributions. Using this framework, we develop a point system to assess whether authorship is justified. Although we recommend discussion and resolution of authorship issues early in the course of any project, our system is especially useful when this has not been done.

Authorship↗
PubMed1998

Graded testosterone infusions distinguish gonadotropin negative-feedback responsiveness in Asian and white men--a Clinical Research Center study.

Recently, multicenter clinical trials to determine male contraceptive efficacy disclosed that testosterone-induced suppression of spermatogenesis to azoospermia occurred in about 90% of Asian but only 60-70% of white men. To test whether there are ethnic differences in the sensitivity of gonadotropin secretion to suppression by testosterone, we administered constant infusions of testosterone at 0, 7, 14, and 28 mg/1.7 m2 x 24 h i.v. for 48 h to 9 Asian and 8 white normal male volunteers (22-42 yr old). During the last 8 h of each infusion dose, 10-min frequent blood sampling was carried out for later LH and FSH measurements by sensitive fluoroimmunoassays. Analyses of LH secretory pulses showed that LH pulse width, height, area, and total area under the curve (LH concentration vs. time) were significantly more suppressed in Asians than in whites during the lowest infusion dose of testosterone. With increasing testosterone dose, the suppression of pulsatile LH secretion was not different in the two ethnic groups. In contrast to pulsatile LH secretion, the responsiveness of pulsatile FSH secretion to exogenous testosterone infusion was not different between the two ethnic groups. At baseline, Asian men had a significantly higher mean number of FSH pulses and mean incremental pulse heights than did white men. Serum inhibin B levels were not distinguishable in the two ethnic groups, but the FSH profiles were quantifiably more irregular (higher approximate entropy) in the Asian volunteers. Our data suggest that, compared with white men, Asian men respond earlier and with more marked suppression of pulsatile LH secretion to ramped testosterone infusions. The elevated basal serum FSH concentrations (and more irregular FSH release pattern) observed in Asian men may suggest a small relative decrease in spermatogenic reserve and/or gonadal negative feedback. Whether these differences contribute to the observed differences in suppression of spermatogenesis in Asians vs. non-Asians in male contraceptive studies is not yet known.

Adult↗
PubMed1996

Applications of segmented regression models for biomedical studies.

In many biological models, a relationship between variables may be modeled as a linear or polynomial function that changes abruptly when an independent variable obtains a threshold level. Usually, the transition point is unknown, and a major objective of the analysis is its estimation. This type of model is known as a segmented regression model. We present two methods, Gallant and Fuller's (J Am. Stat. Assoc. 68: 144-147, 1973) method and Tishler and Zang's (J. Am. Stat. Assoc. 76: 980-987, 1981) method, using nonlinear least-squares techniques for estimating the transition point. We give the following three examples: a hypoglycemia study, a testosterone study, and an estimate of age-cortisol relationship. Simulation techniques are used to compare the two methods. We conclude that these models provide useful information and that the two methods studied produce essentially equivalent results. We recommend that both methods be used to analyze a data set if possible to avoid problems due to local minima and that if the results do not agree, then evaluation of the likelihood function in the range of the estimates be used to determine the best estimate.

Aging↗
PubMed1996

Cognition and white matter hyperintensities in older depressed patients.

OBJECTIVE: The authors compared amounts of white matter hyperintensity in late- and early-onset depressed patients and never-depressed older subjects, compared neuropsychological function in these groups, and investigated the association between white matter hyperintensities and cognitive function in depression. METHOD: Sixty currently depressed patients whose first depression occurred after age 50 years, 35 depressed patients over age 50 whose first depression occurred before age 35, and 165 nonpsychiatrically ill subjects over age 50 underwent magnetic resonance imaging (MRI) and neuropsychological evaluation. Areas of white matter hyperintensity were measured from MRI images. RESULTS: The late-onset patients had more white matter hyperintensity than either of the other groups. Compared to the nondepressed subjects, the patients had significantly lower scores in the cognitive domains of nonverbal intelligence, nonverbal memory, constructional ability, executive ability, and information processing speed. The cognitive abnormalities were mostly confined to the late-onset patients, and the presence of a large amount of white matter hyperintensity was associated with significantly poorer executive skills. However, most of the scores were not in the significantly impaired range. CONCLUSIONS: Large amounts of white matter hyperintensity are more frequent in patients with late-onsetdepression than in elderly subjects with early-onset or no depression. Both late- and early-onset elderly depressed patients show mild decrements in some "right hemisphere" cognitive skills; the late-onset subjects also show deterioration in information processing speed and executive functions. Patients with large amounts of white matter hyperintensity have significantly poorer executive function.

Age Factors↗
PubMed1996

Data from men in greater Seattle area reveals no downward trend in semen quality: further evidence that deterioration of semen quality is not geographically uniform.

OBJECTIVE: To determine whether there has been a decline in semen quality in a group of healthy men during the past 21 years. DESIGN: Retrospective analysis of the relationship between time and changes in semen parameters over 21 years using regression analysis. SETTING: A tertiary university center. PATIENTS: Five hundred ten healthy, normal men who donated multiple semen samples as participants in clinical studies between 1972 and 1993. MAIN OUTCOME MEASURES: Sperm concentration, semen volume, total numbers of sperm per ejaculate, and percent spermatozoa with normal morphology. RESULTS: There was no decrease in sperm concentration, semen volume, total number of sperm per ejaculate, and percent normal sperm morphology in 510 healthy men studied between 1972 and 1993. CONCLUSION: We conclude that in this population of healthy young men there has not been any decline in semen quality in the past 21 years.

Fertility↗
PubMed1995

Rey 15-item memorization and Dot counting scores in a "stress" claim worker's compensation population: relationship to personality (MCMI) scores.

The relationship between apparent faking of cognitive impairment (as detected by such "malingering" tests as 15-item Memorization and Dot Counting) and faking of psychiatric symptoms has not been investigated formally. In addition, no empirical literature is available on the relationship between personality traits and faking of cognitive symptoms. Of 154 subjects who claimed "stress" psychiatric injury, 12% appeared to be faking cognitive impairment; 4.5% failed the 15-item Memorization Test, and 10% failed the Dot Counting task. Faking of cognitive symptoms occurred in only 23% of subjects who were faking/exaggerating psychological symptoms on the MCMI. Malingering test failure was associated with significant elevations on MCMI personality scales, although this appeared to be an artifact of attempts to fake/exaggerate on the MCMI, rather than a reflection of "true" personality traits.

Adolescent↗
PubMed1993

Wisconsin Card Sorting Test performance in healthy, older adults: relationship to age, sex, education, and IQ.

We obtained Wisconsin Card Sorting Test (WCST) scores on 91 (35 male and 56 female) healthy, well-educated individuals aged 45 to 83. Women scored better than men on six WCST scores (categories, errors, perseverative responses, % perseverative errors, % conceptual level responses, and trials to first category), while subjects with more than 16 years of education outscored those limited to high school education on four measures (perseverative responses, errors, % perseverative errors, % conceptual level responses). Individuals older than 70 years of age scored less well than younger subjects on only two indices (errors, % conceptual level responses). Full Scale IQ was not related to WCST scores. Our findings suggest that WCST scores should be interpreted within the context of patient gender, education, and age.

Age Factors↗
PubMed1992

Neuropsychological correlates of white-matter lesions in healthy elderly subjects. A threshold effect.

The clinical significance of white-matter lesions (WMLs) detected by computed tomography and magnetic resonance imaging in healthy elderly subjects has been controversial, with some studies reporting associated deficits in cognition and others failing to document cognitive disturbance. In our sample of 100 healthy elderly individuals, almost half (n = 46) had no WMLs, approximately one fourth had minimal (less than or equal to 1 cm2; n = 27) or moderate (greater than 1 cm2 but less than or equal to 10 cm2; n = 21) WML areas, and six subjects had large WML areas (greater than 10 cm2). Substantial disturbances in basic attention and selected frontal lobe skills were detected in the six subjects with the large WML areas. These findings suggest that a "threshold" of WML area must be present before cognitive deficits are observed. Surprisingly, no significant relationships between duration of hypertension or cholesterol levels and WMLs were detected, suggesting that factors other than vascular disturbances are involved in the origin of at least some WMLs.

Aged↗
PubMed1991

Prenatal lead exposure in the rat during the third week of gestation: long-term behavioral, physiological, and anatomical effects associated with reproduction.

Sprague-Dawley dams were administered lead acetate (0.1%) in their drinking water from Day 14 of gestation to parturition to determine whether exposure of the fetus to elevated lead (Pb) levels during a period of rapid differentiation of the hypothalamic-pituitary-gonadal (HPG) axis would disrupt HPG function in adulthood. At birth, offspring from 20 Pb-treated and 10 control dams were weighed and 2 litter representatives from each sex were fostered to untreated dams. Animals were weaned at 26 days of age and subsequently group housed by sex and treatment. Blood Pb levels in prenatally exposed pups were below the limits of detectability at weaning. Female offspring from Pb-treated dams were found to have a significant delay in the day of vaginal opening. In a sample of lead exposed females, 50% were found to exhibit prolonged and irregular periods of diestrous which was accompanied by an absence of observable corpora lutea when they were euthanized at 83 days of age. Male offspring from these dams were found to have decreased sperm counts at 70 and 160 days of age and to exhibit significantly less territorial scent marking and masculine sex behavior in adulthood compared to controls. Azoospermia was observed in 1 lead exposed animal at 70 days of age and 2 animals at 160 days. Enlarged prostates were observed in Pb-exposed males measured at 160 days, but other sex organ weights were normal. Volume of the sexually dimorphic nucleus of the preoptic area of the hypothalamus in adulthood was significantly reduced by approximately 35% in Pb-exposed males. Pulsatile release of gonadotropins, measured in castrated adult animals of both sexes, revealed irregular release patterns of both FSH and LH in some Pb animals which were not observed in controls. The overall pattern of results suggests that multiple levels of the HPG axis can be affected by exposure to Pb during a period of gestation when structures related to the HPG axis are undergoing rapid proliferation. These data indicate that lead exposure during this period places the exposed animal at significant risk for reduced reproductive capacity in adulthood.

Animals↗
PubMed1990

Effects of yohimbine on bradycardia and duration of recumbency in ketamine/xylazine anesthetized ferrets.

Eleven adult ferrets (Mustela putorius furo) were anesthetized with ketamine hydrochloride (25 mg/kg, IM) and xylazine hydrochloride (2 mg/kg, IM). Fifteen minutes post-ketamine/xylazine injection, ferrets were treated with yohimbine hydrochloride at a dose of 0.5 mg/kg, or an equal volume of physiologic saline, intramuscularly. Each ferret served as its own control by randomly receiving both treatments with a minimum interval of 2 weeks between treatments on any one ferret. At 15 minutes post-ketamine/xylazine injection, mean heart rate measurements for both treatment groups were 27% less than the mean heart rate measurement reported for unanesthetized ferrets. Intramuscular administration of yohimbine antagonized the ketamine/xylazine induced bradycardia in 10 of the 11 ferrets, (p = 0.0001). In yohimbine treated ferrets, an increase in mean heart rate measurement was noted 5 minutes after the intramuscular administration of yohimbine, and followed, over the next 15 minutes, by a progressive increase in mean heart rate. However, a corresponding decrease in mean heart rate measurement was observed in saline treated controls. Fifteen minutes after the injection of yohimbine, the mean heart rate measurement of yohimbine treated animals had increased to 194 beats per minute. This mean heart rate measurement is nearly 30% greater than the mean heart rate of 150 beats per minute measured at 15 minutes post-saline injection in saline treated controls. Also, yohimbine treatment significantly reduced duration of recumbency in 10 of 11 ferrets (p = 0.0001). Mean duration of recumbency for yohimbine treated ferrets was 41 +/- 9.7 minutes, whereas mean duration of recumbency for saline treated ferrets was determined to be 80 +/- 11.4 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Methodological issues in the analysis of human sperm concentration data.

We examined two methodological issues in the analysis of sperm concentration data using a large database of sperm concentrations in healthy men that were collected at the University of Washington. We showed that the raw data were skewed and that log transformation should be used to assure that the data meet the assumptions underlying most statistical estimation and testing procedures. We also addressed the issue of the great variability in sperm concentrations within a single individual and the necessity and utility of multiple sampling to reduce variance. We conclude that log-transformed data should be used for statistical analysis of sperm concentration and recommend that such analyses be based on the geometric mean of several samples from each subject to reduce variability, increase accuracy of estimation, and improve statistical power. This is particularly important when the objective is to detect small but important differences or subtle effects.

Data Interpretation, Statistical↗