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The statistics of identifying differentially expressed genes in Expresso and TM4: a comparison.

BACKGROUND: Analysis of DNA microarray data takes as input spot intensity measurements from scanner software and returns differential expression of genes between two conditions, together with a statistical significance assessment. This process typically consists of two steps: data normalization and identification of differentially expressed genes through statistical analysis. The Expresso microarray experiment management system implements these steps with a two-stage, log-linear ANOVA mixed model technique, tailored to individual experimental designs. The complement of tools in TM4, on the other hand, is based on a number of preset design choices that limit its flexibility. In the TM4 microarray analysis suite, normalization, filter, and analysis methods form an analysis pipeline. TM4 computes integrated intensity values (IIV) from the average intensities and spot pixel counts returned by the scanner software as input to its normalization steps. By contrast, Expresso can use either IIV data or median intensity values (MIV). Here, we compare Expresso and TM4 analysis of two experiments and assess the results against qRT-PCR data. RESULTS: The Expresso analysis using MIV data consistently identifies more genes as differentially expressed, when compared to Expresso analysis with IIV data. The typical TM4 normalization and filtering pipeline corrects systematic intensity-specific bias on a per microarray basis. Subsequent statistical analysis with Expresso or a TM4 t-test can effectively identify differentially expressed genes. The best agreement with qRT-PCR data is obtained through the use of Expresso analysis and MIV data. CONCLUSION: The results of this research are of practical value to biologists who analyze microarray data sets. The TM4 normalization and filtering pipeline corrects microarray-specific systematic bias and complements the normalization stage in Expresso analysis. The results of Expresso using MIV data have the best agreement with qRT-PCR results. In one experiment, MIV is a better choice than IIV as input to data normalization and statistical analysis methods, as it yields as greater number of statistically significant differentially expressed genes; TM4 does not support the choice of MIV input data. Overall, the more flexible and extensive statistical models of Expresso achieve more accurate analytical results, when judged by the yardstick of qRT-PCR data, in the context of an experimental design of modest complexity.

Algorithms↗

Age at onset and cognitive functioning in schizophrenia.

BACKGROUND: Impairments in cognitive functioning are common in schizophrenia, and the degree of impairment may be associated with the individual's age at onset of the disorder. AIMS: To examine the effect of age at onset on cognitive functioning using the California Verbal Learning Test, sub-tests from the Wechsler Memory Scale-Revised and sub-scales from the Wechsler Adult Intelligence Scale-Revised among families with schizophrenia. METHOD: The effect of age at onset on cognitive function in 237 people with schizophrenia from a population-based sample was examined using linear mixed effects models with family as the random effect, and age, gender, chronicity of the illness and number of affected first-degree relatives as fixed effects. RESULTS: Impairment in verbal learning and memory was associated with earlier disease onset. No association was found for working memory or IQ. CONCLUSIONS: In patients with early-onset schizophrenia, verbal memory functions in particular should be taken into account in neuropsychological evaluation and efforts at remediation.

Age of Onset↗

Fatigue and relating factors in high-risk breast cancer patients treated with adjuvant standard or high-dose chemotherapy: a longitudinal study.

PURPOSE: Determine whether standard or high-dose chemotherapy leads to changes in fatigue, hemoglobin (Hb), mental health, muscle and joint pain, and menopausal status from pre- to post-treatment and to evaluate whether fatigue is associated with these factors in disease-free breast cancer patients. PATIENTS AND METHODS: Eight hundred eighty-five patients were randomly assigned between two chemotherapy regimens both followed by radiotherapy and tamoxifen. Fatigue was assessed using vitality scale (score < or = 46 defined as fatigue), poor mental health using mental health scale (score < or = 56 defined as poor mental health) both of Short-Form 36, muscle and joint pain with Rotterdam Symptom Checklist, and Hb levels were assessed before and 1, 2, and 3 years after chemotherapy. RESULTS: Fatigue was reported in 20% of 430 assessable patients (202 standard-dose, 228 high-dose) with at least a 3-year follow-up, without change over time or difference between treatment arms. Mean Hb levels were lower following high-dose chemotherapy. Only 5% of patients experienced fatigue and anemia. Mental health score was the strongest fatigue predictor at all assessment moments. Menopausal status had no effect on fatigue. Linear mixed effect models showed that the higher the Hb level (P = .0006) and mental health score (P < .0001), the less fatigue was experienced. Joint (P < .0001) and muscle pain (P = .0283) were associated with more fatigue. CONCLUSION: In 3 years after treatment, no significant differences in fatigue were found between standard and high-dose chemotherapy. Fatigue did not change over time. The strongest fatigue predictor was poor mental health.

Antineoplastic Agents↗

Diet and biomarkers of oxidative damage in women previously treated for breast cancer.

This study sought to evaluate the relationship between dietary intake of fat, polyunsaturated fat, saturated fat, arachidonic acid, and selected dietary antioxidants and levels of oxidative damage as measured by urinary levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-epi-prostaglandin F2alpha (8-iso-PGF2alpha) in women previously treated for breast cancer. Two hundred two study subjects participating in the Women's Healthy Eating and Living (WHEL) study were included in this ancillary study. Dietary intakes and concentrations of urinary 8-OHdG and 8-iso-PGF2alpha were measured at baseline and 12 mo in the 179 women included in the analytical cohort. Study subjects demonstrated a significant reduction in dietary total, polyunsaturated, and saturated fat intake and a significant increase in vitamins E and C and beta-carotene intake from baseline to 12 mo. Linear mixed-models analysis using baseline and Year 1 data indicated that vitamin E intake was inversely associated with both 8-OHdG and 8-iso-PGF2alpha. 8-Iso-PGF2alpha is increased with increased body mass index (BMI) and polyunsaturated fatty acid (PUFA) intake, indicating an increase in lipid peroxidation with greater BMI and higher PUFA intake. 8-OHdG was inversely related to age but positively related to arachidonic acid, indicating an increase in DNA damage with higher intake of arachidonic acid (meat). The results of this nested case-controlled study provide potential mechanisms by which a high fruit and vegetable, low-fat diet might reduce the recurrence rate of or early-stage breast cancer.

8-Hydroxy-2'-Deoxyguanosine↗

Pharmacokinetic study of the digoxin-acenocoumarol interaction in rabbits.

A study was carried out to evaluate the potential pharmacokinetic interaction between digoxin and acenocoumarol. The binding of digoxin to rabbit cardiac tissue homogenates was assessed in vitro, using the equilibrium dialysis technique. An increase in the first-order constant (p<0.05) and a reduction in the partition coefficient in the equilibrium situation (p<0.001) of digoxin were observed when the cardiac homogenates were previously treated with acenocoumarol. In the in vivo study, the kinetics of digoxin administered in single and multiple dosage regimens were compared in control rabbits and in rabbits treated simultaneously with acenocoumarol. Kinetic analysis of the results was performed using Non-linear Mixed Effects Modeling (NONMEM). In the presence of acenocoumarol, the population distribution volume (Vd) of digoxin was increased by 40-60%, no differences being found as regards the elimination clearance. Also, joint administration of both drugs led to a reduction in digoxin concentrations in the heart (p<0.01) at the end of the dosage regimen. Both sets of results point to the hypothesis of a hitherto unreported possible pharmacokinetic interaction between the two drugs affecting the distribution process. This interaction could lead to lower plasma digoxin levels, in view of the increased Vd, and a possible reduction in the therapeutic effect, owing to the decrease in affinity and in concentration in heart tissue.

Acenocoumarol↗

Particle concentrations in urban microenvironments.

Although ambient particulate matter has been associated with a range of health outcomes, the health risks for individuals depend in part on their daily activities. Information about particle mass concentrations and size distributions in indoor and outdoor microenvironments can help identify high-risk individuals and the significant contributors to personal exposure. To address these issues in an urban setting, we measured particle count concentrations in four size ranges and particulate matter (3/4) 10 microm (PM(10)) concentrations outdoors and in seven indoor microenvironments in Boston, Massachusetts. Particle counts and PM(10) concentrations were continuously measured with two light-scattering devices. Because of the autocorrelation between sequential measurements, we used linear mixed effects models with an AR-1 autoregressive correlation structure to evaluate whether differences between microenvironments were statistically significant. In general, larger particles were elevated in the vicinity of significant human activity, and smaller particles were elevated in the vicinity of combustion sources, with indoor PM(10) concentrations significantly higher than the outdoors on buses and trolleys. Statistical models demonstrated significant variability among some indoor microenvironments, with greater variability for smaller particles. These findings imply that personal exposures can depend on activity patterns and that microenvironmental concentration information can improve the accuracy of personal exposure estimation.

Air Pollutants↗

Is a school-based physical activity intervention effective for increasing tibial bone strength in boys and girls?

UNLABELLED: This 16-month randomized, controlled school-based study compared change in tibial bone strength between 281 boys and girls participating in a daily program of physical activity (Action Schools! BC) and 129 same-sex controls. The simple, pragmatic intervention increased distal tibia bone strength in prepubertal boys; it had no effect in early pubertal boys or pre or early pubertal girls. INTRODUCTION: Numerous school-based exercise interventions have proven effective for enhancing BMC, but none have used pQCT to evaluate the effects of increased loading on bone strength during growth. Thus, our aim was to determine whether a daily program of physical activity, Action Schools! BC (AS! BC) would improve tibial bone strength in boys and girls who were pre- (Tanner stage 1) or early pubertal (Tanner stage 2 or 3) at baseline. MATERIALS AND METHODS: Ten schools were randomized to intervention (INT, 7 schools) or control (CON, 3 schools). The bone-loading component of AS! BC included a daily jumping program (Bounce at the Bell) plus 15 minutes/day of classroom physical activity in addition to regular physical education. We used pQCT to compare 16-month change in bone strength index (BSI, mg2/mm4) at the distal tibia (8% site) and polar strength strain index (SSIp, mm3) at the tibial midshaft (50% site) in 281 boys and girls participating in AS! BC and 129 same-sex controls. We used a linear mixed effects model to analyze our data. RESULTS: Children were 10.2+/-0.6 years at baseline. Intervention boys tended to have a greater increase in BSI (+774.6 mg2/mm4; 95% CI: 672.7, 876.4) than CON boys (+650.9 mg2/mm4; 95% CI: 496.4, 805.4), but the difference was only significant in prepubertal boys (p=0.03 for group x maturity interaction). Intervention boys also tended to have a greater increase in SSIp (+198.6 mm3; 95% CI: 182.9, 214.3) than CON boys (+177.1 mm3; 95% CI: 153.5, 200.7). Change in BSI and SSIp was similar between CON and INT girls. CONCLUSIONS: Our findings suggest that a simple, pragmatic program of daily activity enhances bone strength at the distal tibia in prepubertal boys. The precise exercise prescription needed to elicit a similar response in more mature boys or in girls might be best addressed in a dose-response trial.

Bone Density↗

Level of prenatal cocaine exposure and scores on the Bayley Scales of Infant Development: modifying effects of caregiver, early intervention, and birth weight.

OBJECTIVES: The objectives of this study were 1) to assess whether there is an independent association between the level of prenatal cocaine exposure and infants' developmental test scores after control of potential confounding variables; and 2) if such an association exists, to determine which biological and social variables, individually and in interaction with each other, may modify it. METHODS: In a prospective, longitudinal study of 203 urban term infants, 3 cocaine exposure groups were defined by maternal report and infant meconium assay: unexposed, heavier cocaine exposure (>75th percentile self-reported days of use or meconium benzoylecognine concentration), or lighter cocaine exposure (all others). Examiners, masked to exposure history, tested infants at 6, 12, and 24 months of age with the Bayley Scales of Infant Development. RESULTS: The final mixed linear regression model included as fixed covariates level of prenatal exposure to cocaine, alcohol, and cigarettes; prenatal marijuana exposure; gestational age and birth weight z score for gestational age; and gender. Age at test, caregiver at time of each test (biological mother, kinship caregiver, unrelated foster caregiver), and any previous child-focused early intervention were included as time-dependent covariates. There were no significant adverse main effects of level of cocaine exposure on Mental Development Index (MDI), Psychomotor Development Index (PDI), or Infant Behavior Record. Child-focused early intervention interacted with level of cocaine exposure such that heavily exposed children who received such intervention showed higher adjusted mean MDI scores than all other groups. Although the sample was born at or near term, there was also a significant interaction of cocaine exposure and gestational age on MDI scores, with those in the heavier exposure group born at slightly lower gestational age having higher mean MDI scores compared with other children born at that gestational age. There was also a significant interaction on MDI between child's age and caregiver. At 6 months, the adjusted MDI of children living with a kinship caregiver was 15.5 points lower than that of children living with their biological mother, but this effect was diminished and was no longer significant at 24 months (difference in means: 4.3 points). The adjusted mean MDI of children in unrelated foster care at 6 months was 8.2 points lower than children of biological mothers, whereas it was 7.3 points higher at 24 months. Early intervention attenuated the age-related decline in PDI scores for all groups. Birth weight <10th percentile was associated with lower PDI scores for children with heavier cocaine exposure and with lower MDI scores for all groups. CONCLUSIONS: Heavier prenatal cocaine exposure is not an independent risk factor for depressed scores on the Bayley Scales of Infant Development up to 24 months of age when term infants are compared with lighter exposed or unexposed infants of the same demographic background. Cocaine-exposed infants with birth weight below the 10th percentile for gestational age and gender and those placed with kinship caregivers are at increased risk for less optimal developmental outcomes. Pediatric clinicians should refer cocaine-exposed children to the child-focused developmental interventions available for all children at developmental risk.

Birth Weight↗

Height, weight, and growth in children born to mothers with HIV-1 infection in Europe.

OBJECTIVES: Little is known about the independent long-term effect on growth of exposure to maternal human immunodeficiency virus (HIV) infection. Growth patterns in uninfected children who are born to infected mothers have not been described in detail previously beyond early childhood, and patterns over age for infected and uninfected children have not been based on appropriate general population standards. In vertically HIV-infected children, poor growth has been suggested to be an early marker of infection or progression of disease. However, whether growth faltering is an independent HIV-related symptom or caused indirectly by other HIV clinical symptoms requires clarification. This information is needed to inform the debate on a possible effect of antiretroviral combination therapy on the height of infected children and would provide evidence for the use of specific interventions to improve height. The objective of this study was to describe growth (height and weight) patterns in infected and uninfected children who are born to HIV-infected mothers with respect to standards from a general population and to assess age-related differences in height and weight by infection status, allowing for birth weight, gestational age, gender, HIV-related clinical status, and antiretroviral therapy (ART). METHODS: Since 1987, children who were born to HIV-infected mothers in 11 centers in 8 European countries were enrolled at birth in the European Collaborative Study and followed prospectively according to a standard protocol. Height and weight were measured at every visit, scheduled at birth; 3 and 6 weeks; 3, 6, 9, 12, 15, 18, and 24 months; and every 6 months thereafter. Serial measurements of height and weight from birth to 10 years of age of 1403 uninfected and 184 infected children were assessed. We fitted linear mixed effects models allowing for variance changes over age and within-subject correlation using fractional polynomials and natural cubic splines. Growth patterns were compared with British 1990 growth standards and by infection status. RESULTS: Of the 1587 children enrolled, 810 were male and 777 were female; 1403 were not infected (681 boys, 722 girls), and 184 were infected (88 boys, 96 girls). Neither height nor weight was associated significantly with the main effects of HIV infection status at birth, but differences between infected and uninfected children increased with age. Uninfected children had normal growth patterns from early ages. Infected children were estimated to be significantly shorter and lighter than uninfected children with growth differences increasing with age. Differences in growth velocities between the infected and uninfected children increased after 2 years of age for height and after 4 years of age for weight and were more marked in the latter. Between 6 and 12 months, uninfected children grew an estimated 1.6% faster in height and 6.2% in weight than infected children; between ages 8 and 10 years, these figures were 16% and 44%, respectively. By 10 years, uninfected children were on average an estimated 7 kg heavier and 7.5 cm taller than infected children. Growth in uninfected children who were born before 1994, before the widespread use of ART prophylaxis to reduce vertical transmission, did not substantially differ from that of children who were born after 1994. To investigate whether the growth differences between infected and uninfected children were associated with HIV disease progression, we analyzed growth of infected children using the Centers for Disease Control and Prevention (CDC) clinical classification, in 3 groups: no symptoms, mild or moderate symptoms (A and B), and severe symptoms (C or death). Infected children with mild or serious symptoms lagged behind asymptomatic children in both height and weight, and these differences increased with age. Infected children who were born before availability of ART, before 1988, were more likely to reach a weight below the third centile for age than children who were born after 1994 when effective HIV treatment was widely available. Of the 184 infected children, 67 had been weighed and/or measured at least once while on combination (> or = 2 drugs) ART. Reflecting the longitudinal nature of the European Collaborative Study and the changing availability of HIV treatment, most of these measurements took place after 7 years of age, and therefore analyzing the possible effect of combination therapy on growth is difficult. The z scores for height and weight gain improved substantially in several children who received combination therapy regardless of their CDC clinical classification. To increase available information, we pooled all measurements according to CDC clinical classification and presence of combination therapy at the time of the observation. Weight and height significantly improved for severely ill children after combination therapy. CONCLUSION: Using data from this large prospective European study, we investigated in comparison with general British standards growth patterns in the first 10 years of life of HIV-infected and uninfected children who were born to HIV-infected mothers. The duration of follow-up of uninfected as well as infected children makes this a unique data set. We allowed for repeated measurements for each child and the increase of variability in height and weight with age. Growth faltering may be related to the social environment, and our finding that uninfected children have normal growth, which is unaffected by exposure to maternal HIV infection, is consistent with observations that in Europe the HIV-infected population is more like the general population and less socioeconomically disadvantaged than that in the United States. However, HIV-infected children grew considerably slower, and differences between infected and uninfected children increased with age. Growth patterns in asymptomatic infected children were similar to those with only mild or moderate symptoms. However, compared with these 2 groups combined, severely ill children had poorer growth at all ages. Although limited by the small number of children who received combination therapy, severely ill children may benefit from such therapy in terms of improvements in weight and, to a smaller extent, in height. Growth faltering, particularly stunting, may adversely affect a child's quality of life, especially once they reach adolescence, and this should be taken into account when making decisions about starting and changing ART. Additional research will help to elucidate the relationship between combination therapy and improved growth, in particular regarding different regimens and the best timing of initiation for optimizing growth of infected children.

Acquired Immunodeficiency Syndrome↗

Childhood sexual abuse and age at initiation of injection drug use.

OBJECTIVES: We examined the relation between childhood sexual abuse and injection drug use initiation among young adult injection drug users. METHODS: We used mixed effect linear models to compare age at first injection among 2143 young injection drug users by first sexual abuse age categories. RESULTS: The participants were predominantly male (63.3%) and White (52.8%). Mean age and age at first injection were 23.7 and 19.6 years, respectively; 307 participants (14.3%) reported childhood sexual abuse. After adjustment for gender, race/ethnicity, noninjection drug use before first injection drug use, and recruitment site, childhood sexual abuse was independently associated with younger age at first injection. CONCLUSIONS: Childhood sexual abuse was associated with earlier initiation of injection drug use. These data emphasize the need to integrate substance abuse prevention with postvictimization services for children and adolescents.

Adolescent↗

Social context and geographic patterns of homicide among US black and white males.

OBJECTIVES: The recently published Atlas of United States Mortality depicted striking regional differences in homicide rates for Black and White males in the United States. This study examined these rates to gain an understanding of the contribution of social context to geographic variability in homicide. METHODS: Homicide rates were calculated by health service area for the years 1988 to 1992. The contributions of age, geographic location, urbanization, and sociostructural characteristics were evaluated by means of a weighted linear mixed effects model. RESULTS: Regional differences in urbanization explained much of the geographic variation in homicide rates, but sociostructural factors also had a significant impact. The results suggest that these effects operate similarly for White and Black males, although differences were found in the magnitudes of the effects for the 2 groups. CONCLUSIONS: Results point to a strong association between homicide and urbanization and socioeconomic conditions in all regions of the country for both Black and White males. These findings shed light on the potential correlates of high homicide rates in the United States in the near future.

Adolescent↗

Population pharmacokinetic analysis of bisoprolol.

The technique of population pharmacokinetic analysis was employed to study the variability in the dose concentration relationship of bisoprolol during its clinical development. The influence of demographic factors on the variability of clearance was investigated in 3 different populations: group I, patients (including an elderly group) with essential hypertension receiving multiple oral doses of bisoprolol 10 or 20mg for 3 months; group II, patients with different degrees of renal impairment and healthy controls; and group III, patients with different types of hepatic impairment and healthy controls. Patients and controls in groups II and III received only a single oral dose of bisoprolol 10mg. The 3 data sets were analysed separately, using a non-linear mixed effects model (the NONMEM program). A 2-compartment pharmacokinetic model with first-order absorption described the data adequately. The typical values of volume of central compartment, volume of distribution at steady-state and the absorption rate constant for the 3 populations were: for group I, 68L, 235L, and 0.7h-1; for group II, 28L, 179L, and 0.3h-1; and for group III, 55L, 256L, and 0.4h-1, respectively. Plasma clearance was related to age in group I, to serum creatinine in group II and to aspartate transaminase activity in group III. The 68% confidence limits for clearance and elimination half-life were 8.2 to 21.5 L/h and 7.6 to 19.7h, respectively, for 50-year-old patients in group I. The analysis predicted that progressive increases in serum creatinine or aspartate transaminase activity will result in only a 50% reduction of clearance.

Adrenergic beta-Antagonists↗

The effect of aging on the relationship between the cytochrome P450 2C19 genotype and omeprazole pharmacokinetics.

BACKGROUND AND OBJECTIVE: The metabolic activity of cytochrome P450 (CYP) 2C19 is genetically determined, and the pharmacokinetics of omeprazole, a substrate for CYP2C19, are dependent on the CYP2C19 genotype. However, a discrepancy between the CYP2C19 genotype and omeprazole pharmacokinetics was reported in patients with liver disease or advanced cancer. The objective of the present study was to evaluate the effect of aging on the relationship between the CYP2C19 genotype and its phenotype. METHODS: Twenty-eight elderly and 23 young Japanese volunteers were enrolled after being genotyped. Each subject received a single intravenous dose of omeprazole (10 mg and 20 mg for the elderly and the young groups, respectively) and blood samples were obtained up to 6 hours after dose administration to determine the plasma concentrations of omeprazole and its metabolites, 5-hydroxyomeprazole and omeprazole sulfone. Pharmacokinetic parameters were obtained by noncompartmental analysis. Linear regression models were used to examine the joint effects of covariates such as genotype, age, etc., on the pharmacokinetic parameters, and the pharmacokinetic parameters showing statistical significance were compared by ANOVA. RESULTS: There were significant differences between genotypes in the area under the plasma concentration-time curve of the young group and the elderly group. The number of mutation alleles and age were significant covariates for systemic clearance (CL), but age was the only significant covariate for volume of distribution at steady state (Vss). There were significant age- and genotype-related differences and a significant age x genotype interaction in CL (20.6+/-11.0/12.7+/-4.0/3.2+/-1.0 and 5.4+/-4.0/3.7+/-1.4/2.1+/-0.7 L/h for homozygous extensive metabolisers [EMs]/heterozygous EMs/poor metabolisers [PMs] of the young and the elderly groups, respectively). In Vss, a significant difference was found between the young and the elderly groups (219+/-115 and 107+/-44.5 mL/kg, respectively), but not between three genotypes (178+/-142, 173+/-79 and 110+/-51 mL/kg for homozygous EMs, heterozygous EMs and PMs, respectively). CONCLUSION: The elderly EMs showed wide variance in the in vivo CYP2C19 activity and were phenotypically closer to the elderly PMs than the young EMs were to the young PMs. Some of the elderly homozygous EMs, as well as heterozygous EMs, have a metabolic activity similar to PMs, and the CYP2C19 genotype may therefore not be as useful as phenotyping in the elderly.

2-Pyridinylmethylsulfinylbenzimidazoles↗

Olanzapine. A pharmacoeconomic review of its use in schizophrenia.

UNLABELLED: Olanzapine is an atypical antipsychotic agent which is at least as effective as the conventional agent haloperidol and the atypical agent risperidone. Olanzapine may be superior to haloperidol in some respects, including treatment of negative symptoms. A major advantage of olanzapine over haloperidol is its lower risk of extrapyramidal symptoms. Olanzapine improves quality of life and other aspects of functioning to a greater extent than haloperidol, and improves quality of life to at least the same extent as risperidone. However, olanzapine has a high acquisition cost compared with conventional antipsychotics. Despite this, most pharmacoeconomic analyses indicate that treatment with olanzapine does not significantly increase, and may even decrease, the overall direct treatment costs of schizophrenia, compared with haloperidol. Total direct medical costs calculated from prospective resource utilisation data were lower with olanzapine than with haloperidol by $US388 (1995 values) per patient over 6 weeks and by $US55 per patient per month during 46 weeks extended treatment. In a mixed effects linear model of the same data, total costs over 1 year were $US10,301 (1996 values) per patient lower with olanzapine than haloperidol, and olanzapine was associated with 18.3 more symptom-free days per patient. Compared with risperidone, mean total direct medical costs over 28 weeks were $US493 (1995 values) per patient lower with olanzapine. In a Markov model of 5 years' treatment, olanzapine was associated with more time in a disability-free state than haloperidol at a total cost per patient that was lower by $US1539 (1995 values), 816 Pounds (1995/1996 values), 977 Dutch guilders (NLG; 1995 values) and 2296 Deutschmarks in US, UK, Dutch and German analyses, respectively. In a similar Spanish analysis, the overall total cost was higher with olanzapine, giving an incremental cost effectiveness for olanzapine of 32,516 pesetas (1995 values) per month of disability-free time gained. When risperidone was a comparator, the total cost per patient was $US1875 and NLG202 lower with olanzapine in US and Dutch analyses, respectively. CONCLUSIONS: The high acquisition cost of olanzapine is offset by reductions in other treatment costs in patients with schizophrenia. Compared with haloperidol, the drug improved patient outcome and quality of life, while overall direct treatment costs were generally not increased, or even decreased. Olanzapine has also been reported to decrease overall treatment costs compared with risperidone, but confirmation is required. Olanzapine is a cost-effective alternative to conventional agents for the treatment of moderately to severely ill patients with longstanding schizophrenia.

Antipsychotic Agents↗

Transjugular intrahepatic portosystemic shunts (TIPS): effects of respiratory state and patient position on the measurement of Doppler velocities.

OBJECTIVE: The purpose of this prospective study was to examine the effects of patient position and respiratory state on the measurements of Doppler velocities in transjugular intrahepatic portosystemic shunts. SUBJECTS AND METHODS: Thirty-eight transjugular intrahepatic portosystemic shunts in 34 consecutive patients were studied using Doppler sonography. Peak velocities were measured in the mid shunt with the patient in three positions (supine, sitting upright, and left lateral decubitus) and two respiratory states (deep inspiration and quiet respiration). A mixed linear regression model was used to assess statistically significant differences among the six velocity measurements. RESULTS: Peak velocities in the mid stent averaged 22 cm/sec greater in quiet respiration than in deep inspiration, which was a significant difference (p < 0.00001). Differences in velocities in the three patient positions were not significant (p = 0.53). Using 90-190 cm/sec as the normal range, the peak velocity shifted from normal to abnormal levels by changing respiratory state in 17 (45%) of 38 studies. Using 60 cm/sec as the lower normal limit, the peak velocity fell below the normal range with inspiration in 10 (26%) of 38 studies. In 12 (32%) of 38 studies, a decline in peak velocity exceeding 50 cm/sec could be induced by inspiration. CONCLUSION: Peak systolic velocity in transjugular intrahepatic portosystemic shunts is substantially altered by the respiratory state of the patient at the time of the measurement, but not by the patient position. Respiratory state must be taken into account in the interpretation of peak velocity for shunt stenosis.

Adult↗

Effect of topical administration of 2% dorzlamide hydrochloride or 2% dorzlamide hydrochloride-0.5% timolol maleate on intraocular pressure in clinically normal horses.

OBJECTIVE: To evaluate the effect of topical administration of 2% dorzolamide hydrochloride or 2% dorzolamide hydrochloride-0.5% timolol maleate on intraocular pressure (IOP) in clinically normal horses. ANIMALS: 18 healthy adult horses without ocular abnormalities. PROCEDURE: The IOP was measured at 5 time points (7 AM, 9 AM, 11 AM, 3 PM, 7 PM) over 11 days. On days 1 and 2, baseline values were established. On days 3 through 5, horses received 2% dorzolamide HCI (group D, n = 9) or 2% dorzolamide HCl-0.5% timolol maleate (group DT, 9) in 1 randomly assigned eye every 24 hours immediately following each daily 7 AM IOP measurement. On days 6 through 9, each drug was given every 12 hours (7 AM and 7 PM) in the treated eye. Measurements on days 10 and 11 assessed return to baseline. Mixed linear regression models compared mean IOP difference for each drug at each time period. RESULTS: Mean IOP decreased significantly in all eyes during the 2 dose/d period, compared with the baseline, 1 dose/d, and follow-up periods. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of either drug every 24 hours for short-term treatment does not reduce IOP significantly. Administering either drug every 12 hours induced a significant reduction of IOP; however, controlling for all variables, the reduction was less than 2 mm Hg.

Administration, Topical↗

Effects of caffeine on exercise performance of physically fit Thoroughbreds.

OBJECTIVE: To determine the effects of a dose of caffeine (2.5 mg/kg, IV) administered to physically fit Thoroughbreds during incremental exercise testing to fatigue on a treadmill. ANIMALS: 10 conditioned Thoroughbreds. PROCEDURE: Horses were randomly assigned to receive caffeine or a control solution. Each horse received both treatments in a crossover design with a 3-week interval between treatments. Each horse was administered caffeine (2.5 mg/kg) or an equivalent amount of a control solution IV. One hour after injection, each horse performed an incremental exercise test to exhaustion. Hematologic values, heart rate, oxygen consumption, carbon dioxide production, plasma lactate concentration, urine and serum concentrations of caffeine and metabolites, and time until exhaustion were monitored. Statistical analysis was performed by use of a mixed-effects linear model. RESULTS: Significant differences in measured values when horses were treated with caffeine or the control solution were not detected. CONCLUSIONS AND CLINICAL RELEVANCE: A dose of caffeine (2.5 mg/kg, IV) appears to have no effect on any performance variable of physically fit Thoroughbreds during incremental exercise testing to fatigue.

Animals↗

Genetic parameter estimates of ultrasound-measured longissimus muscle area and 12th rib fat thickness in Brangus cattle.

Data from 2,101 Brangus calves born from 1986 to 1990 were analyzed with a REML procedure using a derivative-free algorithm in a mixed linear animal model to obtain variance component estimates of ultrasound-measured longissimus muscle area and fat thickness. Direct additive heritabilities (ha2) of .39 and .40 were obtained for age-constant weaning and yearling longissimus muscle area (WLMA and YLMA, respectively), with a genetic correlation (rg) of .66 between them. The rg of YLMA with birth weight (BWT), weaning weight (WWT), postweaning gain (PWG), yearling weight (YWT), frame score (FS), and scrotal circumference (SC) were .17, .29, .43, .38, .01, and .19, respectively. The ha2 of age-constant yearling 12th rib fat thickness (FAT) was .14, and cattle averaged .44 cm (SD = .19). Positive rg were obtained between FAT and WLMA (.19) and YLMA (.12). Negative rg of FAT with WWT, YWT, and SC were -.17, -.53, and -.33, respectively. Positive rg were obtained between FAT and BWT (.52), PWG (.44), and FS (.14). Maternal heritabilities (hm2) of WLMA, YLMA, and FAT were .01, .01, and .10, respectively. Weight-constant WLMA, YLMA, and FAT ha2 were .36, .39, and .11, respectively. Selection based on either age-constant YLMA or FAT could potentially result in 1.06 cm2 or .005 cm change per year, respectively, which would be slightly greater than change from selection based on weight-constant YLMA or FAT. Selection based on WLMA or YLMA should be effective, and changes in these traits, growth, and SC should be possible in tandem.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗