Discovery of Dipeptides as Potent Botulinum Neurotoxin A Light-Chain Inhibitors

The botulinum neurotoxin, the caustic agent that causes botulism, is the most lethal toxin known to man. The neurotoxin composed of a heavy chain (HC) and a light chain (LC) enters neurons and cleaves SNARE proteins, leading to flaccid paralysis, which, in severe occurrences, can result in death. A therapeutic target for botulinum neurotoxin (BoNT) intoxication is the LC, a zinc metalloprotease that directly cleaves SNARE proteins. Herein we report dipeptides containing an aromatic connected to the N-terminus via a sulfonamide and a hydroxamic acid at the C-terminus as BoNT/A LC inhibitors. On the basis of a structure-activity relationship study, 33 was discovered to inhibit the BoNT/A LC with an IC₅₀ of 21 nM. X-ray crystallography analysis of 30 and 33 revealed that the dipeptides inhibit through a competitive mechanism and identified several key intermolecular interactions.

Swallowing function following multispecialty organ preservation treatment of advanced head and neck-cancer

Swallowing function was studied in twenty-two patients before, during and after multispecialty (surgical, medical, radiation oncology) organ preservation treatment of advanced pharyngeal and laryngeal carcinoma. Video-fluorographic oropharyngeal motility (OPM) studies were performed at three stages during treatment. Swallowing function was rated according to the Swallowing Performance Status Scale (SPSS). Swallowing function significantly declined after surgery compared to presurgical status but improved significantly after post-surgical concomitant chemoradiotherapy. Swallowing function without need for enteral feeding support was maintained after completion of treatment in 18 of 22 patients (82%). The findings support the need for systematic evaluation of swallowing function throughout the treatment process for patients at risk for pharyngeal dysphagia.

On the use of artificial neural networks for the analysis of survival data

Artificial neural networks are a powerful tool for analyzing data sets where there are complicated nonlinear interactions between the measured inputs and the quantity to be predicted. We show that the results obtained when neural networks are applied to survival data depend critically on the treatment of censoring in the data. When the censoring is modeled correctly, neural networks are a robust model independent technique for the analysis of very large sets of survival data.

Potential particulate impacts at the Grand Canyon from northwestern Mexico

Project MOHAVE was a major air quality and visibility research program conducted from 1990 to 1999 to investigate the causes of visibility impairment in the Grand Canyon National Park region. At Meadview, a remote monitoring site just west of the Grand Canyon National Park, on September 1 and 2, 1992, the concentrations of sulfate (3.1 and 4.3 microg sulfate/m3) were the highest seen in 6 years of monitoring at this site. During this period, the concentrations of SO2 at Meadview were also abnormally high and approximately three times the sulfate concentrations, on a nmol/m3 basis. High concentrations of sulfate and SO2 extended south into southern Arizona and northwestern Mexico. Based on ambient atmospheric conditions, emissions from the Mohave Power Project (MPP) 110 km upwind of Meadview could not have been responsible for the majority of the regionally observed sulfur oxides. The geographical distribution of SO2 and sulfate, and available source information suggest that northwestern Mexico was a significant source of the unusually high observed sulfur oxides. A CMB model developed during Project MOHAVE was used to apportion sulfur oxides at Meadview and other sampling sites throughout the study region for August 31-September 2, 1992. The results indicate that the contribution of MPP to sulfate at Meadview was typical. However, the transport of SOx from northwestern Mexico was elevated throughout much of the region during this time period. This led to the large increase in sulfate concentrations at Meadview on September 1 and 2. These results indicate that emissions from Mexico can be a significant source of particulate material in the Grand Canyon.

Application of fuzzy-classifier system to coronary artery disease and breast cancer

This paper presents an application of a genetic-algorithm-based representation of fuzzy rules for the classification of coronary artery disease data and breast cancer data. The performance of this fuzzy classifier for classification of coronary artery disease and breast cancer data is evaluated. In this study the concept of fuzzy if-then has been applied of rules proposed by Ishibuchi et al. for a multi dimensional data classification problem which leads to higher classification power. The fitness value of each fuzzy if-then rule was determined by the numbers of correctly and wrongly classified training patterns for that rule. The classification power on real world data for coronary artery disease and breast cancer was thus demonstrated by computer simulations.

Restructuring, Democracy, and Geography in New Zealand

The speed, transparency, and extent of the reregulation of New Zealand society over the last decade offer many insights into issues of social change and systems of regulation and governance. The forms of reregulation have been embedded by the set of new regulations and reorganised state practices referred to as the ‘reforms’. These have involved a major shift in the sites and exercise of power within and between economic, social, and political spheres. They have been promoted and articulated in a restructuring discourse which has dominated New Zealand's reaction to the expiry of its social democratic settlement. Reconstructions of space and democracy have been heavily implicated within the processes of change, both as explicit goals of the reform programme and as overt strategies for the achievement of other redistributions. They are also definitive outcomes of a decade of upheaval. The authors explore the spatialities of core-state reform. They develop the concept of an altered dominant representation of space to explore new configurations of space and democratic practice. They seek to inform contemporary debates over the stability of New Zealand's reconstructed social formation. The discussion is illustrated with references to the spatial reorganisation of the institutions of government and core-state activities; in particular the altered administration of education and public health, and changes in local government organisation.

Clinic-based interventions to promote breast and cervical cancer screening

BACKGROUND

Breast and cervical cancer continue to claim the lives of women. Early detection modalities for these cancers are available; however, utilization rates are far from optimal. Studies have documented the motivating effect that physician recommendations have on compliance with preventive health behaviors. The goal of this study was to develop and implement strategies to improve the use of cervical and breast cancer screening among African-American women age 40 and older who resided in low-income housing communities.

METHODS

Baseline surveys among clinic providers and a random sample of women in the target population indicated areas to be included in intervention material. Community health center-based strategies included educational interventions for providers and patients, follow-up interventions for abnormal screening tests, and the implementation of a computer tracking system. Pap smear and mammogram utilization rates at the health center were tracked throughout the project period to assess the effect of the clinic-based interventions.

RESULTS

Both Pap smear and mammography rates increased over time. Fifteen cases of breast cancer and 1 case of invasive cervical cancer have been detected. Compliance rates for follow-up for cervical dysplasia have increased from 50 to 90%.

CONCLUSIONS

These results suggest that clinic-based interventions can improve the use of breast and cervical cancer screening and follow-up among low-income women.

Hydroxyurea with continuous infusion paclitaxel, 5-fluorouracil, and concomitant radiotherapy for poor-prognosis head and neck cancer

Concomitant chemoradiotherapy holds promise in the therapy of advanced head and neck cancer. We have previously reported on the combination of 5-fluorouracil, hydroxyurea, and concomitant chemoradiotherapy administered on an alternate-week basis. In this ongoing study, we are testing the feasibility of adding continuous-infusion paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) to this combination. Background information and early clinical data are presented.

Biomedical image processing in pathology: a review

Pathologists make a diagnostic decision by viewing a specimen and measuring various diagnostically important attributes of an isolated object such as size, shape, darkness, colour and texture. This is a complex process. In recent years, computer-aided image processing and analysis systems have played a significant role in quantitative pathology. This paper summarises basic image processing and analysis techniques and reviews related work in pathology and cytology based on computational image processing since 1987. Firstly, we present a general introduction to image enhancement, segmentation, morphometry and visualisation for those medical colleagues who may not have the necessary background in this area. (The mathematical treatment is kept to minimum and appropriate references are cited to satisfy the more mathematically oriented readers. Selected examples are provided to demonstrate the effects of various basic image processing algorithms on a MRI scan. It should be emphasised that the reviewed techniques are generally used as preprocessing steps in analysing microscopic images and powerful algorithms are more sophisticated and problem-specific.) Secondly, we review image cytometric and histometric methods, standards, calibration and applications. Finally, we touch upon three dimensional confocal image processing and analysis, applications of artificial neural networks, and optical disk database management for recording and retrieving a large number of digitised high resolution images. The development of integrated optical microscope and computer, systems is also briefly described.

Facing the prospect of national health insurance and its impact on group practice

Thomas Weil, Ph.D., in the March/April and May/June MGM Journals speculated on the probability and effects of a national health insurance system. The MGM Journal invited response from several MGMA members and their commentaries appear here.

Spatial patterns of attendance at general practitioner services

Geographical theory suggests that consumers will travel to the centre nearest to their residence which offers a particular service. This is a weak indicator of surgery attendance patterns in Gisborne, New Zealand. Nearby surgeries were attended, rather than the nearest available. Various attributes of the practices and the patients were examined to discover their influence on attendance patterns. The distribution of the practices themselves had a significant effect upon relative surgery attendance. Prior knowledge of services was particularly important in determining surgery selection and continued attendance. This accounted for the spatially unconstrained attendance of many Maori. Greater personal mobility enabled higher income households to travel further to attend. Conversely, the less mobile were spatially bounded.