Mucin-producing tumor of the pancreas: diagnostic value of diffusion-weighted echo-planar MR imaging

It is generally accepted that hemifacial spasm (HFS) and trigeminal neuralgia are caused by compression of the facial nerve (seventh cranial nerve) or the trigeminal nerve (fifth cranial nerve) at the nerve's root exit (or entry) zone (REZ); thus, neurosurgeons generally perform neurovascular decompression at the REZ. Neurosurgeons tend to ignore vascular compression at distal portions of the seventh cranial nerve, even when found incidentally while performing neurovascular decompression at the REZ of that nerve, because compression of distal portions of the seventh cranial nerve has not been regarded as a cause of HFS. Recently the authors treated seven cases of HFS in which compression of the distal portion of the seventh cranial nerve produced symptoms. The anterior inferior cerebellar artery (AICA) was the offending vessel in five of these cases. Great care must be taken not to stretch the internal auditory arteries during manipulation of the AICA because these small arteries are quite vulnerable to surgical manipulation and the patient may experience hearing loss postoperatively. It must be kept in mind that compression of distal portions of the seventh cranial nerve may be responsible for HFS in cases in which neurovascular compression at the REZ is not confirmed intraoperatively and in cases in which neurovascular decompression at the nerve's REZ does not cure HFS. Surgical procedures for decompression of the distal portion of the seventh cranial nerve as well as decompression at the REZ should be performed when a deep vascular groove is noticed at the distal site of compression of the nerve.     

The long-term effect of occlusal therapy on self-administered treatment outcomes of TMD

BACKGROUND: The proteins of halophilic archaea require high salt concentrations both for stability and for activity, whereas they denature at low ionic strength. The structural basis for this phenomenon is not yet well understood. The crystal structure of dihydrofolate reductase (DHFR) from Haloferax volcanii (hv-DHFR) reported here provides the third example of a structure of a protein from a halophilic organism. The enzyme is considered moderately halophilic, as it retains activity and secondary structure at monovalent salt concentrations as low as 0.5 M. RESULTS: The crystal structure of hv-DHFR has been determined at 2.6 A resolution and reveals the same overall fold as that of other DHFRs. The structure is in the apo state, with an open conformation of the active-site gully different from the open conformation seen in other DHFR structures. The unique feature of hv-DHFR is a shift of the alpha helix encompassing residues 46-51 and an accompanied altered conformation of the ensuing loop relative to other DHFRs. Analysis of the charge distribution, amino acid composition, packing and hydrogen-bonding pattern in hv-DHFR and its non-halophilic homologs has been performed. CONCLUSIONS: The moderately halophilic behavior of hv-DHFR is consistent with the lack of striking structural features expected to occur in extremely halophilic proteins. The most notable feature of halophilicity is the presence of clusters of non-interacting negatively charged residues. Such clusters are associated with unfavorable electrostatic energy at low salt concentrations, and may account for the instability of hv-DHFR at salt concentrations lower than 0.5 M. With respect to catalysis, the open conformation seen here is indicative of a conformational transition not reported previously. The impact of this conformation on function and/or halophilicity is unknown.     

Effect of tylosin tartrate on humoral immune responses in chickens

This article examines the 50-year struggle of osteopathic physicians to gain entry into the US Military Medical Corps on the same basis as allopathic physicians. The author explores various arguments put forth by both physician groups, as well as those arguments presented by the respective surgeons general and relevant government officials.     

A new blood compatible and permselective hollow fiber membrane for hemodialysis

The authors have prepared a blood compatible and highly permselective hemodialysis membrane composed of polyether segmented nylon. This block copolymer was synthesized by polycondensation of bis-3-aminopropyl-poly(tetramethylene oxide) (PTMO) and poly(imino-1,3-bismethyl-cyclohexyl-iminoisophtharoyl) (NyBl) prepolymer obtained by polycondensation of 1,3-bis(aminomethyl)cyclohexane (B) and isophthalic acid (I). The molecular weight (MW) calculated from the number of end-groups was 16,000-21,000. In vitro blood compatibility was evaluated in terms of platelet adhesion onto the surface. PTMO-NyBl surfaces showed excellent platelet adhesion preventing properties. The PTMO-NyBl hollow fiber membrane was obtained by a dry-wet spinning process. The membranes had higher permeability coefficients for macromolecules ranging from MW 10,000 to 20,000 than polysulfone hollow fiber membrane (PS membrane), and had acceptably low albumin permeability for use as a dialysis membrane. The ex vivo blood compatibilities of PTMO-NyBl membrane and PS membrane were investigated by extracorporeal circulation in a pig model. The PTMO-NyBl membrane gave excellent results when assessing hemodialysis leukopenia, oxidative burst, and free platelet count decrease.     

Multihormone-producing islet cell tumor of the pancreas associated with somatostatin-immunoreactive amyloid: immunohistochemical and immunoelectron microscopic studies

OBJECTIVE: To assess the association between high but nondiabetic blood glucose levels and the risk of death from all causes, coronary heart disease (CHD), cardiovascular disease, and neoplasms. RESEARCH DESIGN AND METHODS: We studied the 20-year mortality of non-diabetic, working men, age 44-55 years, in three European cohorts known as the Whitehall Study (n = 10,025), the Paris Prospective Study (n = 6,629), and the Helsinki Policeman Study (n = 631). These men were identified by their 2-h glucose levels following an oral glucose tolerance test and by the absence of a prior diagnosis of diabetes. As the protocol for the oral glucose tolerance test and methods for measuring glucose differed between studies, mortality was analyzed according to the percentiles of the 2-h and fasting glucose distributions, using the Cox's proportional hazards model. RESULTS: Men in the upper 20% of the 2-h glucose distributions and those in the upper 2.5% for fasting glucose had a significantly higher risk of all-cause mortality in comparison with men in the lower 80% of these distributions, with age-adjusted hazard ratios of 1.6 (95% CI 1.4-1.9) and 2.0 (1.6-2.6) for the upper 2.5%. For death from cardiovascular and CHD, men in the upper 2.5% of the 2-h and fasting glucose distributions were at higher risk, with age-adjusted hazard ratios for CHD of 1.8 (1.4-2.4) and 2.7 (1.7-4.4), respectively. CONCLUSIONS: If early intervention aimed at lowering blood glucose concentrations can be shown to reduce mortality, it may be justified to lower the levels of both 2-h and fasting glucose, which define diabetes.     

Wind energy planning: Development and application of a site selection method for wind energy conversion systems (WECS)

The use of wind energy by means of its conversion to electricity involves a number of constrains such as economic, environmental, technical, legal, social and institutional requirements. Planning for wind energy should solve these issues in the planning process by encouraging opportunities and discouraging constraints associated with the use of wind energy. The opportunities and constraints significant at the regional level (i.e. approximately 10,000 km²) were identified, and a systematic method was developed to select sites for large WECS by incorporating the identified factors. These factors include: wind resource, proximity to load centres, proximity to tie-in points, and exclusive land-use areas. The developed method was applied to the western Massachusetts region, and the first results of the study have been acquired.