Solitary bronchioloalveolar carcinoma: CT criteria

The computed tomographic (CT) scans of 30 patients with solitary bronchioloalveolar carcinoma were reviewed. Common features at CT included the peripheral or subpleural location of a pulmonary mass (25 cases), pseudocavitation (18 cases), heterogeneous attenuation (17 cases), irregular margins forming a star pattern (22 cases), and pleural tags (21 cases). Using these CT criteria, four independent observers attempted to identify cases of bronchioloalveolar carcinoma from a larger sample of lung cancers and benign lesions by categorizing a series of test cases into four probability categories. Although the bronchioloalveolar carcinomas were correctly ranked in the two highest probability categories 75% of the time (in 45 of 60 cases), there was considerable overlap with other lung lesions, particularly with adenocarcinoma and large cell undifferentiated carcinoma. However, even though the typical features of bronchioloalveolar carcinoma are not invariable or highly specific, they are characteristic enough to suggest the diagnosis.     

Stereologic characterization and spatial distribution patterns of Betz cells in the human primary motor cortex

Betz cells are giant motoneurons located in layer Vb of the primate primary motor cortex. We conducted stereological analyses of Betz cells and neighboring pyramidal cells from the brains of six neurologically normal elderly humans to determine their volume, total number, and spatial distribution, and to relate these data to functional localization. The distribution of cellular volumes exhibits a bimodal pattern, delineating two different subpopulations. Betz cell volumes follow a mediolateral gradient, the largest Betz cells being located on the most medial part of the motor cortex. Additionally, the shape of Betz cells varies between the rostral and caudal parts of the primary motor cortex, supporting the notion that there are anatomically distinct zones in primary motor cortex. The total number of Betz cells per hemisphere accounts for about one-tenth of the total number of pyramidal cells in layer Vb. Analysis of spatial distribution using Voronoi tessellation revealed maximal clustering of Betz cells in a zone situated two-thirds from the midline along the mediolateral axis of the primary motor cortex. These data suggest that Betz cells have a discrete subregional distribution that may correspond to certain aspects of the functional parcellation of area 4. These results may offer a histological correlate of functional imaging studies and are relevant in the context of neurodegenerative diseases such as amyotrophic lateral sclerosis, progressive supranuclear palsy, and Guamanian amyotrophic lateral sclerosis/Parkinsonism-dementia, and in studies of normal brain aging.     

Identification of a gene disrupted by a microdeletion in a patient with X-linked retinitis pigmentosa (XLRP)

The gene for the most frequent from of X-linked retinitis pigmentosa (XLRP), RP3, has been assigned by genetic and physical mapping to a segment of less than 1000 kbp, which is flanked by the marker DXS1110 and the ornithine transcarbamylase (OTC) gene. In search of microdeletions, we have screened the DNA of 30 unrelated patients with XLRP by employing a representative set of YAC-derived DNA fragments that were generated by restriction enzyme digestion and PCR amplification. In one of these patients, a 6.4 kbp microdeletion was detected which was not present in the DNA of 444 male controls. A cosmid contig spanning the deletion was constructed and used to isolate cDNAs from retina-specific libraries. Exons corresponding to these expressed sequences as well as other putative exons were identified by sequencing more than 30 kbp of the critical region. So far, no point mutations in these putative exon sequences have been identified.      

Positional cloning of the gene for X-linked retinitis pigmentosa 3: homology with the guanine-nucleotide-exchange factor RCC1

The gene for retinitis pigmentosa 3 (RP3), the most frequent form of X- linked RP (XLRP), has been mapped previously to a chromosome interval of less than 1000 kbp between the DXS1110 marker and the OTC locus at Xp21.1-p11.4. Employing a novel technique, YAC Representation Hybridization (YRH)', we have recently identified a small XLRP associated microdeletion in this interval, as well as several putative exons including the 3' end of a gene that was truncated by the deletion. cDNA library screening and sequencing of a cosmid centromeric to the deletion has now enabled us to identify numerous additional exons and to detect several point mutations in patients with XLRP. The predicted gene product shows homology to RCC1, the guanine-nucleotide- exchange factor (GEF) of the Ras-like GTPase Ran. Our findings suggest that we have cloned the long-sought RP3 gene, and that it may encode the GEF of a retina-specific GTP-binding protein.      

Effectiveness of denial of handgun purchase to persons believed to be at high risk for firearm violence.

OBJECTIVES: The purpose of this study was to determine whether denial of handgun purchase is an effective violence prevention strategy. METHODS: Individuals denied handgun purchase because of a prior felony conviction and handgun purchasers with a felony arrest at time of purchase were examined. RESULTS: Relative to those denied purchase, handgun purchasers were found to be at greater risk for subsequent offenses involving a gun (relative risk [RR] = 1.21, 95% confidence interval [CI] = 1.08, 1.36) or violence (RR = 1.24, 95% CI = 1.11, 1.39), after adjustment for number of prepurchase weapon/violence charges. CONCLUSIONS: Denial of handgun purchase to persons with a prior felony conviction may lower their rate of subsequent criminal activity.     

Reasons why trauma surgeons fail to screen for alcohol problems.

BACKGROUND: Alcohol screening and intervention have been recommended as routine components of trauma care but are rarely performed. HYPOTHESIS: An association exists between current screening and counseling practices and the trauma surgeon's knowledge, attitude, and perceived role and responsibility toward alcohol problems. PARTICIPANTS: Random-sample survey (n = 241) of members of the American Association for the Surgery of Trauma. MAIN OUTCOME MEASURES: Reported screening and counseling practices. RESULTS: Fifty-four percent of respondents screened 25% or fewer patients, while only 29% screened most patients. The most common reason for not screening was "lack of time." Most (76%) were not familiar with the most common clinically used screening questionnaires, and 83% reported no training in alcohol screening. Screening was more likely if attending physicians perceived a major responsibility for screening (P<.001). Nonscreeners were twice as likely to state screening was "not what I was trained to do" and more frequently believed screening offends patients (P =.001). Independent predictors of screening were perceived major role responsibility (odds ratio [OR], 2.35; 95% confidence interval [CI], 1.38-4.01) and confidence in screening ability (OR, 1.96; 95% CI, 1.05-3.67) and counseling ability (OR, 2.27; 95% CI, 1.34-3.85). Eighty-eight percent of respondents would be willing to devote time to training if shown that counseling is effective. CONCLUSIONS: Lack of screening and counseling appears to be due to cognitive factors, not lack of motivation. Skills on how to screen and counsel for alcohol abuse should be taught to trauma surgeons, because a strong correlation exists between screening and confidence in skills. There is a need for education regarding results of effective intervention trials in medical settings.