Categorization and deductive reasoning: predictors of instrumental activities of daily living performance in adults with brain injury.

OBJECTIVE: The purpose of this study was to examine the predictive relationship of categorization and deductive reasoning abilities to performance of instrumental activities of daily living (IADL) among adults with brain injury. METHOD: A correlational research design was used to examine the performance of 19 patients from a neurosurgery acute care unit on Toglia's Category Assessment (TCA), the Deductive Reasoning test (DR), and the Observed Tasks of Daily Living-Revised. RESULTS: Multiple regression analysis indicated that categorization and deductive reasoning accounted for a significant proportion of the variance in IADL performance scores, with deductive reasoning making the greater contribution. Demographic characteristics such as age and education reduced the power of the previous variables, especially of the categorization. CONCLUSION: The results of this study indicate that assessments of categorization and deductive reasoning abilities of persons with brain injury may be good predictors of IADL functional performance. Results support the use of the TCA and DR as quick measures of a person's cognitive and functional abilities. Furthermore, this study provides preliminary results to support that categorization and deductive reasoning abilities are fundamental for the performance of IADL skills.     

Macroscopic geometric heterogeneity effects in radiation dose distribution analysis for boron neutron capture therapy.

Calculations of radiation flux and dose distributions for boron neutron capture therapy (BNCT) of brain tumors are typically performed using sophisticated three-dimensional analytical models based on either a homogeneous approximation or a simplified few-region approximation to the actual highly heterogeneous geometry of the irradiation volume. Such models should be validated by comparison with calculations using detailed models in which all significant macroscopic tissue heterogeneities and geometric structures are explicitly represented as faithfully as possible. This paper describes such a validation exercise for BNCT of canine brain tumors. Geometric measurements of the canine anatomical structures of interest for this work were performed by dissecting and examining two essentially identical Labrador retriever heads. Chemical analyses of various tissue samples taken during the dissections were conducted to obtain measurements of elemental compositions for the tissues of interest. The resulting geometry and tissue composition data were then used to construct a detailed heterogeneous calculational model of the Labrador head. Calculations of three-dimensional radiation flux distributions pertinent to BNCT were performed for this model using the TORT discrete-ordinates radiation transport code. The calculations were repeated for a corresponding volume-weighted homogeneous-tissue model. Comparison of the results showed that peak neutron and photon flux magnitudes were quite similar for the two models (within 5%), but that the spatial flux profiles were shifted in the heterogeneous model such that the fluxes in some locations away from the peak differed from the corresponding fluxes in the homogeneous model by as much as 10%-20%. Differences of this magnitude can be therapeutically significant, emphasizing the need for proper validation of simplified treatment planning models.     

Dose fractionation of radiolabeled antibodies in patients with metastatic colon cancer.

Twelve patients with metastatic colon cancer were treated with 131I-chimeric B72.3 (IgG-4) at total doses of 28 or 36 mCi/m2 in two or three weekly fractions. Bone marrow suppression was the only significant side effect. The degree of bone marrow suppression adjusted for whole-body dose was modestly but statistically significantly (p = 0.04) less than that seen with identical doses given as a single infusion for the total dose of 36 mCi/m2. Nine of twelve patients developed an antibody response to ch B72.3, which altered the kinetics of radiolabeled antibody in four patients given a second course of therapy. One patient had a minor response that lasted 4 mo. Fractionation of this particular radiolabeled antibody at the dose schedule used produced a modest increase in the therapeutic window in regard to administered dose.     

Nocturnal melatonin plasma levels in patients with OSAS: the effect of CPAP.

Melatonin is a pineal hormone that regulates the human cycle of sleep and wakefulness. Plasma melatonin levels were investigated in patients with obstructive sleep apnoea syndrome (OSAS). In total, 20 patients with OSAS and 11 healthy controls were studied. OSAS patients were tested twice: on the night of diagnostic polysomnography and the night of continuous positive airway pressure (CPAP) titration. Controls were tested on one occasion. Plasma melatonin levels were determined at 23:00 h (light period), at 02:00 h (dark period) and at 06:00 h (light period) in patients and control subjects using the radioimmunoassay method. The control subjects showed a nocturnal melatonin peak value at 02:00 h (70.6+/-14 pg.mL(-1)). However, this nocturnal melatonin peak was absent in the OSAS patients. The highest melatonin value was found in OSAS patients on the night of diagnosis, at 06:00 h (49.3+/-36.8 pg.mL(-1)). It was found that the melatonin level in OSAS patients at 06:00 h was significantly lower in the night of titration (35.6+/-37.9 pg.mL(-1)) than in the diagnosis night. However, the melatonin levels at either 23:00 h or 02:00 h in OSAS patients did not differ significantly when comparing levels in the night of diagnostic polysomnography (23:00 h: 31.6+/-29.8 pg.mL(-1); 02:00 h: 47.4+/-33.8 pg.mL(-1)) with levels in the night of CPAP titration (23:00 h: 20.2+/-10.3 pg.mL(-1); 02:00 h: 37.7+/-27.5 pg.mL(-1)). Patients with obstructive sleep apnoea syndrome have an abnormal melatonin secretion pattern. The absence of a nocturnal serum melatonin peak could be partially related to the difficulty that these patients have in achieving a normal sleep-wakefulness pattern.     

3He MRI in mouse models of asthma.

In the study of asthma, a vital role is played by mouse models, because knockout or transgenic methods can be used to alter disease pathways and identify therapeutic targets that affect lung function. Assessment of lung function in rodents by available methods is insensitive because these techniques lack regional specificity. A more sensitive method for evaluating lung function in human asthma patients uses hyperpolarized (HP) (3)He MRI before and after bronchoconstriction induced by methacholine (MCh). We now report the ability to perform such (3)He imaging of MCh response in mice, where voxels must be approximately 3000 times smaller than in humans and (3)He diffusion becomes an impediment to resolving the airways. We show three-dimensional (3D) images that reveal airway structure down to the fifth branching and visualize ventilation at a resolution of 125 x 125 x 1000 microm(3). Images of ovalbumin (OVA)-sensitized mice acquired after MCh show both airway closure and ventilation loss. To also observe the MCh response in naive mice, we developed a non-slice-selective 2D protocol with 187 x 187 microm(2) resolution that was fast enough to record the MCh response and recovery with 12-s temporal resolution. The extension of (3)He MRI to mouse models should make it a valuable translational tool in asthma research.