Single photon emission computed tomographic blood flow and magnetic resonance volume imaging of basal ganglia in Huntington''s disease

During oogenesis in Drosophila, germ cells appear in sequential clusters of 16 interconnected cells. The events surrounding the differentiation of these cells are not fully understood. Here we present genetic and morphological analysis of mutations in the gene stand still (stil). Through complementation analyses we have refined the location of this gene to cyological region 49B-C. Our analyses of ovaries from ethylmethane sulfonate (EMS)-induced mutant alleles of this gene suggest that mutations in the stil gene produce a wide range of phenotypic abnormalities, from the absence of germ cells in the most severe alleles, to egg chambers with cytoskeletal defects in the less severe alleles. Our results suggest a role for this gene in specifying or maintaining a cytoskeletal component, with consequences during oogenesis and possibly during germ line sex determination.     

Managing watershed resources

Watersheds, as integrated land and water systems, have proved difficult to manage successfully. This is in part due to the complexities of accommodating different groups of users and making use of multiple resources in spatially large areas. The paper argues, however, that watersheds have a natural physical and economic logic as a unit of analysis. As a bridge between microlevel analysis of individual farmers or economic units and a regional or sectoral approach, the watershed, when analyzed in an integrated, multi-disciplinary manner, yields useful policy results for improved management of land and water resources. Economic analysis plays a key role in this analysis. Integrated analysis, however, does not mean integrated implementation. Existing systems of social and government organization must be used to implement the chosen policies. This is a difficult, but essential step and may require the use of government fiscal and price policies to harmonize social and private goals.The views expressed in this paper are those of the author, who is Research Associate with the East-West Environment and Policy Institute, Honolulu, Hawaii. Parts of this paper draw on Dixon [5], prepared for the Economic Development Institute of the World Bank.     

Pain drawings in the assessment of nerve root compression: a comparative study with lumbar spine magnetic resonance imaging

STUDY DESIGN: Prospective comparative study of pain drawings with findings on lumbar spine magnetic resonance imaging. OBJECTIVES: To assess the ability of the pain drawing to predict the presence of nerve root compression. SUMMARY OF BACKGROUND DATA: Most research work has concentrated on the ability of the pain drawing to act as a screening method for psychological distress with less work directed at the influence the anatomic abnormality has on the pain drawing. METHODS: One hundred thirty-four consecutive outpatients attending for lumbar magnetic resonance imaging in the investigation of back and leg pain completed pain drawings and psychological testing immediately before the examination. The pain drawing was analyzed by previously reported criteria, and the magnetic resonance imaging was assessed independently for the presence of nerve compression by three radiologists. Multivariate stepwise discriminant analysis was used to identify patients with nerve compression on the basis of their pain drawing. RESULTS: Nerve compression was predicted by numbness in the anterolateral aspect of the foot. There was considerable overlap in the appearances of the pain drawings between patients with and without nerve compression, and the pain drawing correctly classified only 58% of patients with nerve compression. CONCLUSIONS: The pain drawing is not a good predictor of nerve compression on magnetic resonance imaging in a group of patients investigated for back and leg pain. It should be interpreted with caution and in light of the full clinical picture.     

Metastatic pulmonary artery sarcoma. Report of a case with diagnosis by fine needle aspiration

Spontaneously hypertensive rats (SHR) of 3 to 12 months of age learned and retrieved less information than normotensive Wistar-Kyoto rats (WKY), although no difference was found with animals from 18 and 24 months of age. The combined influence of hypertension and aging had an additive detrimental effect on cognitive functions. Notwithstanding these deficiencies in learning and memory, SHR have seldom been used as a model in the screening of drugs with therapeutic potential for treatment of disorders of cognitive processes. Moreover, the calcium channel blocker nimodipine has beneficial effects on learning in both aged and hypertensive animals and humans. However, no attempt has been made to investigate whether nimodipine can reverse the additive deleterious effects of aging and hypertension in the same subject. We recently reported that deteriorated animals (middle-aged and/or hypertensive) chronically treated with nimodipine (via osmotic minipumps) exhibit higher learning scores. This information indicates that nimodipine can reverse the impairing effects of either aging or hypertension on learning; the presence of the two conditions, however, produces a severe impairment that can be partially reversed by this drug. Therefore, we propose that mature and middle-aged SHR represent a model for the screening of potentially useful drugs in the treatment of learning disorders, probably associated with hypertension and/or aging. Nevertheless, it must be remembered that the SHR is a genetic model and the appearance of neural disturbances could be a parallel genetic phenomenon and not necessarily or exclusively related to hypertension per se.     

Mechanisms involved in the intrinsic isoniazid resistance of Mycobacterium avium

Isoniazid (INH), which acts by inhibiting mycolic acid biosynthesis, is very potent against the tuberculous mycobacteria. It is about 100-fold less effective against Mycobacterium avium. This difference has often been attributed to a decreased permeability of the cell wall. We measured the rate of conversion of radiolabelled INH to 4-pyridylmethanol by whole cells and cell-free extracts and estimated the permeability barrier imposed by the cell wall to INH influx in Mycobacterium tuberculosis and M. avium. There was no significant difference in the relative permeability to INH between these two species. However, the total conversion rate in M. tuberculosis was found to be four times greater. Examination of in vitro-generated mutants revealed that the major resistance mechanism for both species is loss of the catalase-peroxidase KatG. Analysis of lipid and protein biosynthetic profiles demonstrated that the molecular target of activated INH was identical for both species. M. avium, however, formed colonies at INH concentrations inhibitory for mycolic acid biosynthesis. These mycolate-deficient M. avium exhibited altered colony morphologies, modified cell wall ultrastructure and were 10-fold more sensitive to treatment with hydrophobic antibiotics, such as rifampin. These findings may significantly impact the design of new therapeutic regimens for the treatment of infections with atypical mycobacteria.     

High-performance liquid chromatography determination of mycophenolic acid and its glucuronide metabolite in human plasma

Two HPLC-UV assays are reported here: one is a rapid assay for mycophenolic acid (MPA) and the other is a simultaneous assay for MPA and its metabolite mycophenolic acid glucuronide (MPAG). For both methods, plasma samples (500 microl) with added internal standard were acidified and extracted using C18 solid-phase extraction cartridges. Chromatographic separation was achieved on a C18 Novapak column using a mobile phase consisting of methanol-0.05% orthophosphoric acid (40:60, v/v) for the rapid MPA assay and 30:70 for the simultaneous MPA and MPAG assay. The assays were linear over the ranges 0.1 to 50.0 mg/l for MPA and 2.8 to 225.8 mg/l for MPAG. Mean absolute recovery for all analytes was >99%. These methods are suitable for therapeutic drug monitoring and pharmacokinetic studies.     

Decrease in muscle glutamine, ribosomes, and the nitrogen losses are similar after laparoscopic compared with open cholecystectomy during the immediate postoperative period

A number of studies have localized CGRP to nerves in the cornea and iris, and it is thought that CGRP, along with other neuropeptides, is involved in pain sensation. It is also possible that CGRP could mediate trophic influences between nerve endings and corneal epithelium. This investigation utilized an in vitro rabbit corneal whole mount preparation to study the effect of topical 2.5 microM CGRP application on epithelial wound healing rates of 5 mm diameter epithelial wounds. CGRP (2.5 microM) was applied topically to 5 mm epithelial wounds at 0, 4, 16, 20, 24, 28, 40, 44, 48, 52, 56, 64, 68, and 72 hours after wounding and healing was visualized with fluorescein. CGRP was found to increase the epithelial wound healing rate by 25%, from 51 +/- 3 microns/hr for the control corneas, to 64 +/- 2 microns/hr for CGRP-treated corneas (mean +/- standard error, n = 10). Histological examination of the corneas following healing showed that the epithelium of the CGRP-treated corneas healed in a similar manner as in the control corneas. These findings may have clinical utility for the understanding and treatment of corneal and other epithelial wounds.     

Microprocessor IDDQ testing: a case study

The author describe their incorporation of I_DDQ testing into the design of the PA-7100LC PA-RISC microprocessor. They also discuss design guidelines, measurement techniques, results after fabrication and volume production, and suggested improvement. Their 900,000-transistor custom design supports I_DDQ testing to ensure high quality without compromising 100-MHz-plus performance