Assessing the effect of electron density in photon dose calculations.

Photon dose calculation algorithms (such as the pencil beam and collapsed cone, CC) model the attenuation of a primary photon beam in media other than water, by using pathlength scaling based on the relative mass density of the media to water. In this study, we assess if differences in the electron density between the water and media, with different atomic composition, can influence the accuracy of conventional photon dose calculations algorithms. A comparison is performed between an electron-density scaling method and the standard mass-density scaling method for (i) tissues present in the human body (such as bone, muscle, etc.

Sample exchange to compare insulin measurements between the San Antonio Heart Study and the Framingham Offspring Study.

Lack of assay standardization has precluded cross-study comparison of insulin levels. We exchanged blood samples between the San Antonio Heart and Framingham Offspring Studies to compare insulin measurements. Two randomly selected specimens were chosen for each non-diabetic man and woman in each of the bottom four quintiles and top two deciles of the originally assayed fasting and 2-hour post-challenge insulin distributions: 48 plasma samples from Framingham, and after further stratification by ethnicity, 96 serum samples from San Antonio.

Genetic influences on attention deficit hyperactivity disorder.

In this article we review behavioral and molecular genetics studies of attention deficit hyperactivity disorder (ADHD). Family, twin, and adoption studies, along with segregation analyses and molecular genetic studies, all support the hypothesis that both genetic and environmental factors contribute to the etiology of ADHD. Despite this strong evidence for the familial transmission of ADHD, the mode of transmission requires further clarification.

Coaxial imaging technique for superior hypogastric plexus block.

Background And Objectives: Previously described techniques for superior hypogastric plexus (SHP) block are technically difficult. A simple coaxial imaging technique for SHP block is described.

Methods And Results: Fluoroscopic guidance for coaxial approach to SHP block is described.

Retroductive reasoning in a proposed subtype of partial seizures, evoked by limbic "kindling".

This analysis provides a specific example of the generally applicable process of creative delineation of a novel pattern while searching for an explanatory hypothesis for puzzling observations. In so doing, the neglected retroductive form of inference or abduction was used. Central to such a process is the delineation of a specific "generative mechanism" capable of uniting and explaining heretofore unexplained phenomena.

Elevation of neuronal MAO-B activity in a transgenic mouse model does not increase sensitivity to the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP).

To examine whether expressing high levels of monoamine oxidase (MAO-B) activity abberently in neurons results in increased sensitivity of dopaminergic neurons to the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), 8-week-old transgenic mice expressing high neuronal levels of MAO-B were compared with age-matched nontransgenic littermates following i.p. injections of 30 mg/kg body weight of the protoxin.

Antibody-targeted photolysis of bacteria in vivo.

We have evaluated the efficacy of antibody-targeted photolysis to kill bacteria in vivo using specific antibacterial photosensitizer (PS) immunconjugates. After infecting the dorsal skin in mice with Pseudomonas aeruginosa, both specific and nonspecific tin (IV) chlorin e6-monoclonal antibody conjugates were injected at the infection site. After a 15 min incubation period, the site was exposed to 630 nm light with a power density of 100 mW/cm2 for 1600 seconds.

Privacy on trial in Massachusetts: Commonwealth v. Stockhammer.

Health records are not always private. In this case, the court said that a defendant in a rape case could see certain medical records pertaining to the victim's hospitalization for an unrelated overdose that occurred months after the attack. This article explores the legal decision and its impact on medical privacy.

Gene transfer into mammalian central nervous system using herpes virus vectors: extended expression of bacterial lacZ in neurons using the neuron-specific enolase promoter.

A herpes simplex virus (HSV) vector in which the mammalian promoter for neuron-specific enolase (NSE) controls expression of a marker gene was analyzed for its ability to drive expression of this foreign gene in culture and in vivo. In cultured cells, the vector appeared to give neuron-specific expression. Introduction of 10(6) pfu of the virus into the adult rat caudate nucleus by stereotactic injection was not toxic to the animals and yielded beta-galactosidase (beta-gal)-positive neurons for at least 30 days after viral inoculation.

Nosocomial pneumonia: interdisciplinary quality monitoring.

Nosocomial pneumonia is a serious and potentially fatal occurrence in the hospital today. Medical and nursing management influence the susceptibility of an individual as well the outcome of the episode. Due to the importance of the actions of the nurse and of the physician, monitoring the risk factors of the patient, the events preceding the episode and the pneumonia management may provide an opportunity to improve patient care.

Correlation of clinical and histopathologic features in clinically atypical melanocytic nevi.

To define better the evolving entity of dysplastic melanocytic nevus (DMN), studies correlating clinical with histologic features of DMN are essential. However, based on a literature search, no previous quantitative analysis was found of the relationship between gross morphologic features and histologic features of DMN. The authors correlated individual clinical features with histopathologic features and histologic diagnosis of the clinically most atypical nevus in 153 melanoma patients.

Individual psychotherapy with mentally retarded individuals: a review and call for research.

Although most mental health professionals doubt the capacity of mentally retarded patients to benefit from psychotherapy, a review of case studies, writings, and research revealed that mentally retarded patients responded positively to treatment. Practitioners familiar with this population developed six major recommendations for adapting psychotherapeutic approaches to mentally retarded patients. In order for therapy to be successful, it is recommended that clinicians adapt standard technique to the patient's cognitive level, be directive in approach, be flexible during therapy, engage significant others in the therapeutic process, carefully manage transference and countertransference issues, and directly address the issue of mental retardation as a disability.

Language and learning disorders of older boys with Duchenne muscular dystrophy.

The IQs of 25 males with Duchenne muscular dystrophy were determined and the results were pooled with those for 76 others reported in the literature to examine the relationship between IQ and age. Verbal IQ was significantly lower than Performance IQ among the younger boys, but not the older. The distribution of Verbal IQ of the older boys was bimodal, suggesting that a verbal deficit persists in some cases.

Reading disability subtypes in neurologically-impaired students.

Three studies were conducted in order to determine if reading disability subtypes identified by Mattis, Boder, and Doehring were present in neurologically-impaired students with and without reading disabilities. The anomic-language disorder subtype, dysphonetic and mixed dysphonetic-dyseidetic subtypes, and Doehring's three subtypes were all present, primarily in the reading-disabled sample. Subtypes related to visual-spatial impairment were equally or more apparent in the non-reading-disabled sample.