Diffusion modeling of percutaneous absorption kinetics: 2. Finite vehicle volume and solvent deposited solids

The diffusion model for percutaneous absorption is developed for the specific case of delivery to the skin being limited by the application of a finite amount of solute. Two cases are considered; in the first, there is an application of a finite donor (vehicle) volume, and in the second, there are solvent-deposited solids and a thin vehicle with a high partition coefficient. In both cases, the potential effect of an interfacial resistance at the stratum corneum surface is also considered. As in the previous paper, which was concerned with the application of a constant donor concentration, clearance limitations due to the viable eqidermis, the in vitro sampling rate, or perfusion rate in vivo are included. Numerical inversion of the Laplace domain solutions was used for simulations of solute flux and cumulative amount absorbed and to model specific examples of percutaneous absorption of solvent-deposited solids. It was concluded that numerical inversions of the Laplace domain solutions for a diffusion model of the percutaneous absorption, using standard scientific software (such as SCIENTIST, MicroMath Scientific software) on modern personal computers, is a practical alternative to computation of infinite series solutions. Limits of the Laplace domain solutions were used to define the moments of the flux-time profiles for finite donor volumes and the slope of the terminal log flux-time profile. The mean transit time could be related to the diffusion time through stratum corneum, viable epidermal, and donor diffusion layer resistances and clearance from the receptor phase. Approximate expressions for the time to reach maximum flux (peak time) and maximum flux were also derived. The model was then validated using reported amount-time and flux-time profiles for finite doses applied to the skin. It was concluded that for very small donor phase volume or for very large stratum corneum-vehicle partitioning coefficients (e.g., for solvent deposited solids), the flux and amount of solute absorbed are affected by receptor conditions to a lesser extent than is obvious for a constant donor constant donor concentrations. (C) 2001 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 90:504-520, 2001.

Using a cartographic modeling language to manipulate spectral satellite imagery

Land related information about the Earth's surface is commonIJ found in two forms: (1) map infornlation and (2) satellite image da ta. Satellite imagery provides a good visual picture of what is on the ground but complex image processing is required to interpret features in an image scene. Increasingly, methods are being sought to integrate the knowledge embodied in mop information into the interpretation task, or, alternatively, to bypass interpretation and perform biophysical modeling directly on derived data sources. A cartographic modeling language, as a generic map analysis package, is suggested as a means to integrate geographical knowledge and imagery in a process-oriented view of the Earth. Specialized cartographic models may be developed by users, which incorporate mapping information in performing land classification. In addition, a cartographic modeling language may be enhanced with operators suited to processing remotely sensed imagery. We demonstrate the usefulness of a cartographic modeling language for pre-processing satellite imagery, and define two nerv cartographic operators that evaluate image neighborhoods as post-processing operations to interpret thematic map values. The language and operators are demonstrated with an example image classification task.

Cognitive behaviour therapy for the management of obsessive-compulsive disorder

Current research reflects conflict regarding best practice in the treatment of obsessive-compulsive disorder (OCD). The. present study reports on the psychological treatment of a 54-year-old woman diagnosed with OCD, and follows the implementation of pharmacological treatment. The study utilises both exposure and response prevention (ERP) and cognitive therapy (CT), although there was no attempt to compare these approaches in an experimental design. Measures of avoiding and neutralising behaviours were taken on three occasions across treatment. Measures were also taken of intrusive thoughts, appraisal of responsibility, and effective challenging, both across treatment and at follow-up. The results indicate that gains were made in addition to those reported following the implementation of medication. The results also suggest that the addition of CT to exposure and response prevention facilitates the extinction of neutralising behaviours.

The future of cognitive and behavioral therapies in the prevention and early management of psychosis: Opportunities and risks

Behavioral and cognitive interventions for people with psychosis have a long and distinguished history, although the evidence for their application to young people remains limited. We anticipate that the next decades will show substantial research into psychological intervention for this population. Important targets will include the management of environmental stressors, reduction of substance misuse, and promotion of early treatment. Psychological management of positive symptoms, depression, and suicidal behavior will continue to be critical objectives. Important secondary prevention goals will be the retention of cognitive functioning, vocational options, social skills, and social network support, including appropriate family support. We expect primary prevention to include both universal programs and interventions for adolescents at particularly high risk. Technical innovations will include increasing use of Internet-based intervention and behavior cueing devices. Pressures for intervention brevity will continue, as will problems with the systematic delivery of effective procedures.

Outpatient cognitive behavioural therapy programme for alcohol dependence impact of naltrexone use on outcome

Objective: Cognitive-behavioural therapy (CBT) has been effectively used in the treatment of alcohol dependence. Clinical studies report that the anticraving drug naltrexone, is a useful adjunct to treatment. Currently, few data are available on the impact of adding this medication to programmes in more typical, outpatient, and rehabilitation settings. The objective of this study was to examine the impact on outcome of adding naltrexone to an established outpatient alcohol rehabilitation program which employed CBT. Method: Fifty patients participated in an established 12-week, outpatient, 'contract'-based alcohol abstinence programme which employed CBT. They also received naltrexone 50 mg orally daily (CBT + naltrexone). Outcomes were compared with 50 historical, matched controls, all of whom participated in the same programme without an anticraving medication (CBT alone). All patients met DSM-IV criteria for alcohol dependence. Results: Programme attendance across the eight treatment sessions was lower in the CBT alone group (p < 0.001). Relapse to alcohol use occurred sooner and more frequently in the CBT alone group (p < 0.001). Rehabilitation programme completion at 12 weeks was 88% (CBT + naltrexone) compared with 36% for (CBT alone) (p < 0.001). Alcohol abstinence at 12 weeks was 76% (CBT + naltrexone) compared with 18% (CBT alone) (p < 0.001). Conclusion: When employing the same outpatient rehabilitation programme and comparing outcomes using matched historical controls, the addition of naltrexone substantially improves programme attendance, programme completion and reported alcohol abstinence. In a typical outpatient programme, naltrexone addition was associated with significantly improved programme participation, better outcomes and was well tolerated.

Childhood neglect and cognitive development in extremely low birth weight infants: A prospective study

Objective. To examine the relationship between child maltreatment and cognitive development in extremely low birth weight infants, adjusting for perinatal and parental risk factors. Methods. A total of 352 infants with birth weight of