Chorus wave power at the strong diffusion limit overcomes electron losses due to strong diffusion

Earth's radiation belts consist of high-energy charged particles trapped by Earth's magnetic field. Strong pitch angle diffusion of electrons caused by wave-particle interaction in Earth's radiation belts has primarily been considered as a loss process, as trapped electrons are rapidly diffused into the loss cone and lost to the atmosphere. However, the wave power necessary to produce strong diffusion should also produce rapid energy diffusion, and has not been considered in this context. Here we provide evidence of strong diffusion using satellite data. We use two-dimensional Fokker-Planck simulations of electron diffusion in pitch angle and energy to show that scaling up chorus wave power to the strong diffusion limit produces rapid acceleration of electrons, sufficient to outweigh the losses due to strong diffusion. The rate of losses saturates at the strong diffusion limit, whilst the rate of acceleration does not. This leads to the surprising result of an increase, not a decrease in the trapped electron population during strong diffusion due to chorus waves as expected when treating strong diffusion as a loss process. Our results suggest there is a tipping point in chorus wave power between net loss and net acceleration that global radiation belt models need to capture to better forecast hazardous radiation levels that damage satellites.

Randomized Trial Based on the Common-Sense Model of Self-regulation to Increase Child Dental Visits

INTRODUCTION

School screening and the note home (pinned to a backpack) informing parents/caregivers that their child needs to see a dentist have not been effective.

OBJECTIVES

The Family Access to a Dentist Study (FADS) evaluated the effectiveness of school interventions based on the common-sense model of self-regulation (CSM) among K-4 children needing restorative treatment.

METHODS

FADS was a multisite double-blind randomized controlled trial with 5 arms. FADS tested a CSM-driven referral letter and dental information guide (DIG) to move caregivers from inaccurate to accurate perceptions of dental caries. Six school districts from Ohio and Washington (14 schools) participated in school years 2015 to 2016 and 2016 to 2017. A total of 611 caregivers were randomized, and 86% (n = 597 children) completed the exit examination. The primary outcome was receipt of care based on a change in oral health status determined clinically within 1 school year.

RESULTS

In accordance with our primary aims, 5 arms were collapsed into 3: CSM letter and reduced CSM letter (combined), CSM letter + DIG and reduced CSM letter + reduced DIG (combined), and standard letter. Among all sites, 39.7% received restorative care (237 of 597). Combined analysis of sites revealed that the CSM referral letter (with and without the DIG) did not increase dental visits when compared with the standard letter. However, for combined sites (East Cleveland, Ohio; Washington), the CSM + DIG increased dental visits when compared with standard letter in univariate analysis (51.3% vs. 40.9%), indicating 1.6-times increased odds of a dental visit (95% CI, 0.97 to 2.58) after imputation and adjustment for covariates. The CSM + DIG group had 1.9-times increased odds (95% CI, 1.21 to 3.08) of care when compared the CSM letter alone.

CONCLUSION

A CSM-driven approach to informing caregivers of the chronic nature of caries with resources in an illustrative manner can increase the benefit of school oral health screening (ClinicalTrials.gov NCT02395120).

KNOWLEDGE TRANSFER STATEMENT

A school dental referral (note home) that tells a parent that the child has cavities has not been effective. In this trial, a referral based on the common-sense model of self-regulation increased follow-up care for children with restorative needs.

Increased enamel hypoplasia and very low birthweight infants

Birth cohort studies of developmental defects of enamel (DDE) and early childhood caries (ECC) in very low birthweight (VLBW) and normal birthweight (NBW) infants are rare. In this birth cohort of 234 VLBW and 234 NBW infants, we report the incidence of ECC and DDE at 8 and 18-20 mos of corrected age. Infant medical and maternal socio-demographic data were abstracted from medical records at birth. Dental assessments for ECC and DDE (enamel hypoplasia, demarcated and diffuse opacities) were completed at 8 and 18-20 mos. The incidence of hypoplasia was significantly higher in VLBW compared with NBW infants (8 mos, 19% vs. 2%; 18 mos, 31% vs. 8%). The incidence of ECC (International Caries Detection and Assessment System: ICDAS ≥ 2) was 1.4% (8 mos) and 12% (18-20 mos) and was similar between the VLBW and NBW groups. At both ages, using a beta-binomial regression model to control for potential confounders (maternal and infant characteristics), we found increased risk for enamel hypoplasia among the VLBW infants compared with the NBW infants. African Americans had a lower risk for enamel hypoplasia at 18-20 mos. The VLBW infants should be monitored for ECC due to the presence of enamel hypoplasia.

Early maternal psychosocial factors are predictors for adolescent caries

Few studies have investigated the role of early maternal enabling and psychosocial factors on subsequent adolescent caries experience. In this retrospective cohort study of 224 adolescents, we hypothesized that the causal pathway between early maternal enabling factors (education, cognitive abilities, psychological distress) and adolescent caries experience (DMFT) at age 14 yrs is mediated by maternal psychosocial factors (stress, coping, social support) and adolescent dental behavior/access. Maternal data on socio-demographic, medical, and psychosocial variables were measured when the child was 3, 8, and 14 yrs old. A structural equations model (SEM) evaluated the causal pathway, with latent variables for maternal enabling factors (MEF), stress, coping, and social support. Poor MEF was associated with increased stress and poorer coping when the child was 3 yrs old, which in turn affected adolescent dental visits and behavior. Greater social support at child's age 3 was directly associated with lower mean DMFT in adolescence. Maternal psychosocial factors measured when children are young are important mediators for adolescent mean DMFT, but these factors measured when children are adolescents are not. Better early and concurrent MEF, however, was associated directly/indirectly (through dental visits and insurance) with adolescent DMFT. Early maternal factors are important predictors for adolescent caries.

Dental caries and enamel defects in very low birth weight adolescents

OBJECTIVES

The purpose of this study was to examine developmental enamel defects and dental caries in very low birth weight adolescents with high risk (HR-VLBW) and low risk (LR-VLBW) compared to full-term (term) adolescents.

METHODS

The sample consisted of 224 subjects (80 HR-VLBW, 59 LR-VLBW, 85 term adolescents) recruited from an ongoing longitudinal study. Sociodemographic and medical information was available from birth. Dental examination of the adolescent at the 14-year visit included: enamel defects (opacity and hypoplasia); decayed, missing, filled teeth of incisors and molars (DMFT-IM) and of overall permanent teeth (DMFT); Simplified Oral Hygiene Index for debris/calculus on teeth, and sealant presence. A caregiver questionnaire completed simultaneously assessed dental behavior, access, insurance status and prevention factors. Hierarchical analysis utilized the zero-inflated negative binomial model and zero-inflated Poisson model.

RESULTS

The zero-inflated negative binomial model controlling for sociodemographic variables indicated that the LR-VLBW group had an estimated 75% increase (p < 0.05) in number of demarcated opacities in the incisors and first molar teeth compared to the term group. Hierarchical modeling indicated that demarcated opacities were a significant predictor of DMFT-IM after control for relevant covariates. The term adolescents had significantly increased DMFT-IM and DMFT scores compared to the LR-VLBW adolescents.

CONCLUSION

LR-VLBW was a significant risk factor for increased enamel defects in the permanent incisors and first molars. Term children had increased caries compared to the LR-VLBW group. The effect of birth group and enamel defects on caries has to be investigated longitudinally from birth.

Incidence and risk factors for hip or other bone fractures among hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study

The available data on bone fractures in hemodialysis (HD) patients are limited to results of a few studies of subgroups of patients in the United States. This study describes the prevalence of hip fractures and the incidence and risk factors associated with hip and other fractures in representative groups of HD facilities (n=320) and patients (n=12 782) from the 12 countries in the second phase of the Dialysis Outcomes and Practice Patterns Study (2002-2004). Among prevalent patients, 2.6% had a prior hip fracture. The incidence of fractures was 8.9 per 1000 patient years for new hip fractures and 25.6 per 1000 for any new fracture. Older age (relative risk (RR)(HIP)=1.91, RR(ANY)=1.33, P<0.0001), female sex (RR(HIP)=1.41, P=0.02; RR(ANY)=1.59, P<0.0001), prior kidney transplant (RR(HIP)=2.35, P=0.04; RR(ANY)=1.76, P=0.007), and low serum albumin (RR(HIP)=1.85, RR(ANY)=1.45, per 1 g/dl lower, P<0.0001) were predictive of new fractures. Elevated risk of new hip fracture was observed for selective serotonin reuptake inhibitors and combination narcotic medications (RR=1.63, RR=1.74, respectively, P<0.05). Several medications were associated with risk of any new fracture: narcotic pain medications (RR=1.67, P=0.02), benzodiazepines (RR=1.31, P=0.03), adrenal cortical steroids (RR=1.40, P<0.05), and combination narcotic medications (RR=1.72, P=0.001). Parathyroid hormone (PTH) levels >900 pg/ml were associated with an elevated risk of any new fracture (RR=1.72, P<0.05) versus PTH 150-300. The results suggest that greater selectivity in prescribing several classes of psychoactive drugs and more efficient treatment of secondary hyperparathyroidism may help reduce the burden of fractures in HD patients.

Lack of health insurance and decline in overall health in late middle age

BACKGROUND

The number of adults in their 50s and 60s in the United States who do not have health insurance is increasing. This group may be particularly vulnerable to the ill effects of being uninsured.

METHODS

We conducted a prospective cohort study using files from the Health and Retirement Study, a national survey of adults who were 51 to 61 years old in 1992. We determined the risks of a major decline in overall health and of the development of new physical difficulties between 1992 and 1996 for participants who were continuously uninsured (uninsured in 1992 and in 1994), those who were intermittently uninsured (uninsured either in 1992 or in 1994), and those who were continuously insured. We used logistic regression to determine the independent effects of being uninsured on health outcomes after adjustment for base-line sociodemographic factors, preexisting medical conditions, and types of health-related behavior such as smoking and alcohol use.

RESULTS

We analyzed data for 7577 participants. The 717 continuously uninsured participants and the 825 intermittently uninsured participants were more likely than the 6035 continuously insured participants to have a major decline in overall health between 1992 and 1996 (21.6 percent, 16.1 percent, and 8.3 percent of the three groups, respectively; P<0.001 for both comparisons). According to a multivariate analysis, the adjusted relative risk of a major decline in overall health was 1.63 (95 percent confidence interval, 1.26 to 2.08) for continuously uninsured participants and 1.41 (95 percent confidence interval, 1.11 to 1.78) for intermittently uninsured participants, as compared with continuously insured participants. A new difficulty in walking or climbing stairs was also more likely to develop in the continuously or intermittently uninsured participants than in the continuously insured participants (28.8 percent, 26.4 percent, and 17.1 percent of the three groups, respectively; P<0.001 for both comparisons). The adjusted relative risk of such a new physical difficulty was 1.23 (95 percent confidence interval, 1.02 to 1.47) for the continuously uninsured participants and 1.26 (95 percent confidence interval, 1.01 to 1.54) for the intermittently uninsured participants.

CONCLUSIONS

The lack of health insurance is associated with an increased risk of a decline in overall health among adults 51 to 61 years old.

Statistical advances in AIDS therapy trials

This paper reviews recent statistical advances in HIV/AIDS therapy trials. Our emphasis is on three emerging areas that address key challenges in AIDS research: the determination of optimal treatment sequences, estimating efficacy of intended treatment, and inference for repeated measures with dependent censoring. A common theme of these topics is the use of observational data within clinical trials to answer questions not addressed by the conventional intent-to-treat analysis. We also give a brief overview of some recent contributions to other topics relevant to AIDS clinical trials, including modelling of treatment compliance data, modelling of repeated measures, and group sequential testing.

Impaired growth and elevated fas receptor expression in PIGA(+) stem cells in primary paroxysmal nocturnal hemoglobinuria

The genetic defect underlying paroxysmal nocturnal hemoglobinuria (PNH) has been shown to reside in PIGA, a gene that encodes an element required for the first step in glycophosphatidylinositol anchor assembly. Why PIGA-mutated cells are able to expand in PNH marrow, however, is as yet unclear. To address this question, we compared the growth of affected CD59(-)CD34(+) and unaffected CD59(+)CD34(+) cells from patients with that of normal CD59(+)CD34(+) cells in liquid culture. One hundred FACS-sorted cells were added per well into microtiter plates, and after 11 days at 37 degrees C the progeny were counted and were analyzed for their differentiation pattern. We found that CD59(-)CD34(+) cells from PNH patients proliferated to levels approaching those of normal cells, but that CD59(+)CD34(+) cells from the patients gave rise to 20- to 140-fold fewer cells. Prior to sorting, the patients' CD59(-) and CD59(+)CD34(+) cells were equivalent with respect to early differentiation markers, and following culture, the CD45 differentiation patterns were identical to those of control CD34(+) cells. Further analyses of the unsorted CD59(+)CD34(+) population, however, showed elevated levels of Fas receptor. Addition of agonist anti-Fas mAb to cultures reduced the CD59(+)CD34(+) cell yield by up to 78% but had a minimal effect on the CD59(-)CD34(+) cells, whereas antagonist anti-Fas mAb enhanced the yield by up to 250%. These results suggest that expansion of PIGA-mutated cells in PNH marrow is due to a growth defect in nonmutated cells, and that greater susceptibility to apoptosis is one factor involved in the growth impairment.

A threshold causal model for clinical trials with departures from intended treatment

Randomized clinical trials often are planned to study a specific intervention. However, the collection of data on treatment actually received often reveals variable levels of treatment exposure (or 'dose') across subjects, due to non-compliance or other reasons. This paper presents a new method, using such 'dose' data as well as control group responses, to assess a causal dose-response relationship. The specific model utilizes a threshold function and incorporates a random effect term to allow for heterogeneous treatment responses among subjects. Further modelling of the random effects allows for reduction of error variance and control for potential confounders. The threshold dose is estimated using a residual variance criterion based on a transformed model. Estimates of standard errors and confidence intervals are obtained using a bootstrap procedure. The method is applied to data from an AIDS clinical trial. A simulation study demonstrates the adequacy of the threshold estimates for particular sample sizes and error variances. The limitations of this essentially exploratory method, as well as some possible extensions, are discussed. Published in 1999 by John Wiley & Sons, Ltd. This article is a US Government Work and is in the public domain in the United States.

Relationship between event rates and treatment effects in clinical site differences within multicenter trials: an example from primary Pneumocystis carinii prophylaxis

The results of multicenter clinical trials may differ across participating clinical sites. We present a diagnostic approach for evaluating this diversity that emphasizes the relationship between the observed event rates and treatment effects. We use as an example a trial of sequential strategies of Pneumocystis prophylaxis in human immunodeficiency virus infection with 842 patients randomly allocated to start prophylaxis with trimethoprim/sulfamethoxazole, dapsone, or pentamidine. Prophylaxis failure rates varied significantly across the 30 clinical sites (0-30.3%, p = 0.002 by Fisher's exact test) with prominent variability in the pentamidine arm (0-63.6%). Starting with oral regimens was better than starting with pentamidine in sites with high rates of events, whereas the three strategies had more similar efficacy in other sites. Sites enrolling fewer patients had lower event rates and had more patients who withdrew prematurely or were lost to follow-up. In a hierarchical regression model adjusting for random measurement error in the observed event rates, starting with trimethoprim/sulfamethoxazole was predicted to be increasingly better than starting with aerosolized pentamidine as the risk of prophylaxis failure increased (p = 0.01), reducing the risk of failure by 47% when the failure rate of pentamidine was 30%, whereas the two regimens were predicted to be equivalent when the failure rate was 17%. Differences in event rates could reflect a combination of heterogeneity in diagnosis, administration of treatments, and disease risk in patients across sites. The evaluation of clinical site differences with a systematic approach focusing on event rates may give further insight in the interpretation of the results of multicenter trials beyond an average treatment effect.

A randomized trial of high- versus low-dose subcutaneous interleukin-2 outpatient therapy for early human immunodeficiency virus type 1 infection

Forty-nine outpatients infected with human immunodeficiency virus with baseline CD4 cell counts >/=500/mm3, who were on stable antiretroviral therapy, were randomized to receive 5-day cycles of either low-dose (1.5 million IU [MIU] twice a day) or high-dose (7.5 MIU twice a day) subcutaneous (sc) interleukin (IL)-2 every 4 or every 8 weeks. High-dose recipients experienced mean slopes of +116.1 cells/month and +2.7 %/month in CD4 cells and percents, respectively, whereas low-dose recipients displayed mean slopes of +26.7 and +1.3% in the same parameters. At month 6, high-dose recipients achieved a 94.8% increase in mean CD4 cells over baseline compared with a 19.0% increase in low-dose recipients. While high-dose recipients encountered more constitutional side effects, these were generally not dose-limiting. High-dose scIL-2 therapy in outpatients with early HIV-1 infection was well tolerated and induced dramatic, sustained rises in CD4 cells.

Statistical issues for HIV surrogate endpoints: point/counterpoint. An NIAID workshop

This paper summarizes the proceedings of an NIAID-sponsored workshop on statistical issues for HIV surrogate endpoints. The workshop brought together statisticians and clinicians in an attempt to shed light on some unresolved issues in the use of HIV laboratory markers (such as HIV RNA and CD4+ cell counts) in the design and analysis of clinical studies and in patient management. Utilizing a debate format, the workshop explored a series of specific questions dealing with the relationship between markers and clinical endpoints, and the choice of endpoints and methods of analysis in clinical studies. This paper provides the position statements from the two debaters on each issue. Consensus conclusions, based on the presentations and discussion, are outlined. While not providing final answers, we hope that these discussions have helped clarify a number of issues, and will stimulate further consideration of some of the highlighted problems. These issues will be critical in the proper assessment and use of future therapies for HIV disease.

A control-conditional test for assessing HIV vaccine efficacy in small sample preclinical studies

In this paper, we discuss the analysis of data from small sample animal studies intended to evaluate HIV vaccine efficacy. The focus is on the chimpanzee model with HIV infection, a binary outcome, of primary interest. The problem becomes that of testing for a difference in independent binomial proportions, but aspects of the study design call into question the use of standard approaches. As sample sizes may be as small as one or two per group in this context, it is tempting to utilize previous data; such usage, however, carries a high price in terms of additional assumptions. We present a test, referred to as the control-conditional test, which conditions on the control data and assumes (in a manner of Bayesian estimation) only vague prior information. Comparisons are made with Fisher's exact test and an exact unconditional test. The control-conditional test is also generalized to allow the analysis of data from a differential dose design.

Controlled trial of interleukin-2 infusions in patients infected with the human immunodeficiency virus

BACKGROUND

Interleukin-2 is a cytokine that regulates the proliferation and differentiation of lymphocytes. In preliminary studies, intermittent infusions of interleukin-2 led to increases in CD4 counts in patients with human immunodeficiency virus (HIV) infection and more than 200 CD4 cells per cubic millimeter. We conducted a controlled study to evaluate the long-term effects of such therapy on both CD4 counts and the viral burden.

METHODS

Sixty HIV-infected patients with base-line CD4 counts above 200 cells per cubic millimeter were randomly assigned to receive either interleukin-2 plus antiretroviral therapy (31 patients, 1 of whom was lost to follow-up) or antiretroviral therapy alone (29 patients). Interleukin-2 was administered every two months for six cycles of five days each, starting at a dosage of 18 million i.u. per day. Safety and immunologic and virologic measures were monitored monthly until four months after the last treatment cycle.

RESULTS

In patients treated with interleukin-2, the mean (+/-SE) CD4 count increased from 428 +/- 25 cells per cubic millimeter at base line to 916 +/- 128 at month 12, whereas in the control group, the mean CD4 count decreased from 406 +/- 29 cells per cubic millimeter to 349 +/- 41 (P < 0.001). There were no significant differences between the groups in serial measurements of the plasma HIV RNA or p24 antigen concentration during the 12 months of treatment. Constitutional symptoms (fever, malaise, and fatigue) and asymptomatic hyperbilirubinemia were the chief dose-limiting toxic effects of interleukin-2 therapy.

CONCLUSIONS

In patients with HIV infection and base-line CD4 counts above 200 cells per cubic millimeter, intermittent infusions of interleukin-2 produced substantial and sustained increases in CD4 counts with no associated increase in plasma HIV RNA levels.

Quantified EEG changes associated with a positive clinical response to clozapine in schizophrenia

1. The authors conducted a retrospective exploratory computerized EEG study on the effect of clozapine in treatment-refractory schizophrenics, 10 high-responders (HRs) and 10 low-responders (LRs), in an attempt to correlate amplitude but especially coherence changes with a positive clinical response to clozapine. 2. EEGs with eyes closed were obtained before and during a clozapine treatment. Both groups had a similar drug profile with regards to non-clozapine medication. Probability maps were computed to illustrate changes of amplitude and coherence (for all combinations of paired electrodes) for 4 frequency bands (theta, alpha, beta 1 and 2). 3. The effect on AMPLITUDE was a generalized increase in lower bands and a decrease in anterior regions in higher bands of both HRs and LRs. Considerable changes of COHERENCE were observed on a wide set of paired electrodes in most frequency bands with some electrodes involved in HRs but uninvolved or differently involved in LRs suggesting differences in selected brain regions. 4. Changes of coherence but not amplitude were correlated with changes on the BPRS, thus to clinical improvement, and concerned mostly the right anterior-medial temporal (T4) and central (C4) electrodes paired with prefrontal electrodes, left central (C3), temporal (T3) and parietal (P3) electrodes in the theta band. 5. Clozapine has both generalized and regional effects as can be suspected considering its effect on many subtypes of brain receptors. A brain dysfunction centralized on the right anterior-medial temporal region may characterize treatment-refractory schizophrenics.

Structure and induction pattern of a novel proteinase inhibitor class II gene of tobacco

A cDNA and a corresponding genomic clone encoding a protein with partial identity to type II proteinase inhibitors from potato, tomato and Nicotiana alata, were isolated from tobacco libraries. The protein of 197 amino acids contains a putative signal peptide of 24 residues and three homologous domains, each with a different reactive site. The tobacco PI-II gene is not expressed in leaves of healthy plants, but is locally induced in leaves subjected to different types of stress (TMV infection, wounding, UV irradiation) and upon ethephon treatment. As opposed to the analogous PI-II genes of potato and tomato, the tobacco gene is not systemically induced by wounding or pathogenic infection. A far-upstream region in the PI-II promoter, containing various direct and indirect repeats, shares considerable sequence similarity to a similar region in the stress-inducible Cu/Zn-superoxide dismutase gene of N. plumbaginifolia.

Brain activation with a maze test: an EEG coherence analysis study in healthy subjects

The maze test is a complex cognitive task involving visuoperceptual, planning and foresight abilities. EEGs were recorded from 20 healthy subjects according to the 10/20 system. Coherence is analogous to a correlation coefficient between the signals recorded by two electrodes and is computed between each electrode paired to all other electrodes. The maze test provoked changes of coherence mainly within the prefrontal regions, between parietal and central electrodes paired with frontal electrodes, especially the right frontopolar and the left prefrontal electrodes, and in the posterior temporal, parietal and occipital regions. EEG coherence analysis detects changes in regions known to be involved in visual processing and executive functions.

On a model-based approach to estimating efficacy in clinical trials

Treatment efficacy is of primary importance in phase III clinical trials. Determining the true size of the treatment effect is often complicated by patient non-compliance with the regimen. This paper examines a model-based approach in the spirit of Efron and Feldman utilizing drug and placebo compliance information. One of the assumptions of this analysis is 'comparability' of drug and placebo compliance. Robustness in estimation of subgroup and population treatment effects when this assumption is violated is investigated in a simulation study. We find that even moderate non-comparability (for example, normalized compliance correlations of 0.4) may produce severely biased estimates. The basis is modulated by the strength of the relationship between compliance and the response on placebo.

Bronchopulmonary dysplasia and postnatal growth in extremely premature black infants

Bronchopulmonary dysplasia (BPD) may adversely affect the postnatal growth of the extremely premature infant; however, most studies have not controlled for birth weight. We studied 90 Black premature infants (mean birth weight 989 +/- 148 g). Weight was recorded biweekly until discharge and at 4, 8, and 12 months of age corrected for prematurity. Infants with BPD (N = 23) were contrasted with infants without BPD (N = 67). Data were modeled using the Count model: Stage I birth to term and Stage II term to 12 months. Birth weight was considered part of growth beginning in utero and multivariate analyses were used to control for BPD, gestational age, duration of hospitalization and socioeconomic status. After adjustment for birth weight, BPD did not explain the growth pattern. A lower gestational age was associated with a slower establishment of steady growth (P less than 0.01), while an increased duration of hospitalization was associated with a lower growth rate (P less than 0.05). Growth in stage II was not explained by study variables. 'Catch-up' growth was seen in both infants with and without BPD. We conclude that differences in growth among infants with BPD are mainly attributable to birth weight. We speculate that poorer growth may be seen in a sub-group of infants with severe BPD.

Patient-controlled analgesia vs. conventional intramuscular analgesia following colon surgery

Though patient-controlled analgesia (PCA) has been in use for over a decade, it has been popularized only recently. Conventional techniques of intermittent intramuscular (IM) administration of analgesia have fallen short of meeting the needs of patients following major abdominal surgery. This has prompted a search for methods to improve postoperative pain management. Though PCA has been accepted in many hospitals, few studies comparing conventional IM administration of morphine with PCA have been performed. A prospective randomized study comparing IM- and PCA-administered morphine in 62 patients undergoing colon surgery was performed. A comparison of the efficacy of analgesia and extent of sedation using these approaches shows that PCA allows for analgesia with less sedation and less drug requirement than that of IM administration. No differences were noted in postoperative duration of ileus, duration of hospitalization, and total hospital costs. This study confirms the safety and efficacy of PCA, and should be considered the current optimal method of controlling pain following major colonic surgery.

Calcifying dermatomyositis following antitetanus vaccination

In the course of dermatomyositis, calcinosis is a complication frequently seen in children but rarely seen in adults. Calcinosis often induces poor functional prognosis, reducing mobility of the joints and muscles. Dermatomyositis developed in a 59-year-old woman, following an antitetanus vaccination; the dermatomyositis later became calcifying. To our knowledge, similar cases have not been reported.

Comparison of SCH-12679 and thioridazine in aggressive mental retardates

SCH-12679, a benzazepine derivative, was compared to thioridazine and to placebo on the aggressive behaviour of mentally retarded patients. After a three-week chlorpromazine (100 mg t.i.d.) standardizaton period, no significant differences between the three treatment groups were observed in their abnormal behaviour. During the comparative phase, patients treated with SCH-12679 became less hyperative and less agitated while those treated with thioridazine became more violent, more choleric and more provocative. The clinical investigator and the nursing staff found significant differences between the active drugs. As compared to the placebo, SCH-12679 improved the behaviour of the patients while thioridazine aggravated their condition. No important adverse reaction was found and the drugs did not interact with the sex of the patients and the presence of epilepsy. The results suggest that, in mental retardation, physical restraint of hyperactivity might induce aggressivity and that one should be cautious in using neuroleptics in nonpsychotic patients.

Gas-liquid chromatographic method for the measurement of plasma levels of d-7,8-dimethoxy-3-methyl-phenyl-2,3,4,5-tetrahydro-1h-3-benzazepine acid maleate (SCH-12679) and its major metabolites in aggressive mental retardites

A sensitive gas-liquid chromatographic technique for the quantitative analysis of SCH-12679 (d-7,8-dimethoxy-3-methyl-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine acid maleate) and its major metabolites in plasma of aggressive mental retardates receiving therapeutic doses of the medicament has been developed. The lower limits of detection are 20 ng/ml for SCH-12679, 0.5 ng/ml for 3-desmethyl SCH-12679 and 0.4 ng/ml for 7-desmethyl plus 8-desmethyl SCH-12679. SCH-12679 is estimated with a flame ionization detector. Its metabolites are quantitated using an electron-capture detector after conversion of the compounds to their heptafluorobutyryl derivatives by reaction with the appropriate anhydride. Data on plasma levels of unchanged SCH-12679, 3-desmethyl SCH-12679 and a combination of 7-desmethyl and 8-desmethyl SCH-12679 in fifteen patients treated with the medicament are presented.

Metabolic interaction between amitriptyline and perphenazine in psychiatric patients

1. Steady-state plasma level samples of sixty-five schizophrenic patients from two psychiatric hospitals assigned to three treatment groups (amitriptyline 150 mg/day, perphenazine 20 mg/day and a combination of amitriptyline and perphenazine at 150 mg and 20 mg/day) were assayed for amitriptyline (AT), endogenous nortriptyline (NT) and perphenazine (PPZ) using gas-liquid chromatography. 2. Results reveal that AT and NT levels are independent of sex and hospital environment. 3. PPZ significantly increased the steady-state NT plasma levels, probably through inhibition of the hydroxylation biotransformation pathway, but had no effect on AT levels, thus indicating that PPZ has no influence on the desmethylation pathway, or alternatively, the hydroxylation of AT.

Amitriptyline-perphenazine interaction in ambulatory schizophrenic patients. A controled study of drug interaction

In a double-blind placebo, controlled clinical study, lasting 12 weeks, 48 male and 48 female ambulatory schizophrenic patients were randomly assigned to one of four treatments: placebo; amitriptyline hydrochloride, 125 mg/day; perphenazine, 20 mg/day; or amitriptyline-perphenazine, 20 mg/day. Treatment groups contained an equal number of male and female patients. Perphenazine alone or in combination was substantially more effective in reducing psychopathological disorder than was the placebo, but there was no evidence to indicate the superiority of the amitriptyline-perphenazine combination over perphenazine alone. Amitriptyline alone was not substantially better than placebo and could not be considered an efficacious medication for the maintenance treatment of these patients. Less response to treatment was made by patients with longer-term records of prior hospitalization.

Penfluridol steady-state kinetics in psychiatric patients

Twenty-two hospitalized schizophrenic patients, participating in a large-scale phase II double-blind dose-effect study (30, 60, and 120 mg weekly) of penfluridol, a new diphenylbutylpiperidine neuroleptic, were maintained on a regular dosage regimen for 13 wk. Several blood samples were taken during the last dosage interval. Results show that the peak concentration develops within 12 hr after the last dose. A rapid decline, probably due to tissue re-equilibration, then occurs and is followed by a much slower falloff. Detectable concentrations 168 hr after administration are consistent with the long duration of action of penfluridol. Statistically significant differences between doses were found in the analysis of variance of plasma concentrations at all sampling times and in mean steady-state plasm concentrations. Wide differences in plasma concentrations were noted in patients receiving the same absolute dose, but a good relationship was defined between mean steady-state concentration and the dose expressed as mg per either kg of body weight or square meter of body surface area.

Gas-liquid chromatographic determination of penfluridol in plasma. A new specific technique

Penfluridol is a new long-acting neuroleptic drug, first shown by Janssen et al. (1970) and later proved by numerous clinical investigations. The plasma level data are in agreement with these findings since penfluridol is measurable in plasma of the patients 7 days after the oral dose of 120 mg/week. In summary, we have provided for the first time a rapid, accurate and precise gas-chromatographic method for measurement of penfluridol in the plasma of schizophrenic patients.