Parathyroid arteriography

Parathyroid arteriography and venous sampling for parathormone are the best techniques presently available for preoperative localization of hyperplastic and neoplastic parathyroid tissue. Inaccuracy of the technique, risk of complications, and relatively high cost make the routine use of arteriography and venous sampling inappropriate. They are, however, a useful preoperative adjunct in the patient who has undergone a previously unsuccessful neck exploration.     

Membrane microviscosity and human platelet function

An increased sensitivity to epinephrine-induced aggregation has been observed both in platelets obtained from patients with type IIa hyperlipoproteinemia and in normal platelets following incubation with cholesterol-rich lecithin dispersions. We have reported previously that the membrane fraction of platelets is enriched with cholesterol relative to phospholipid under each of these conditions. To further explore the effect of cholesterol on platelet membranes, we have examined the fluidity (microviscosity) of whole platelets and platelet subcellular fractions using a hydrophobic fluorescent probe, 1,6-diphenyl-1,3,5-hexatriene (DPH), under conditions in which the cholesterol-to-phospholipid mole ratio (C/PL) of platelets was varied by incubation with various cholesterol-lecithin sonicated dispersions. The C/PL of platelets directly influenced the rotational diffusion of DPH, as indicated by changes in fluorescence polarization. This was reflected in an increase in microviscosity at 37 degrees C (ETA37) from 2.84 P in normal platelets to 4.06 P in platelets with a 118% increase in C/PL. Conversely, platelets with a 43% decrease in C/PL had a 13% decrease in eta37. A strong correlation (r = 0.94) existed between C/PL and eta37 throughout this entire range. However, C/PL had no effect on the excited-state fluorescence lifetime of DPH. Both C/PL and eta37 were lower in isolated platelet membranes than in the platelet granule fraction. When platelets were incubated for 20 h with cholesterol-rich dispersions, there was an increase in C/PL and eta37 in both the membrane and granule fractions. However, this occurred more rapidly in membranes so that, at 5 h (a time when an increased sensitivity of whole platelets to epinephrine is evident), membrane C/PL had increased 55% and eta37 had increased 42%, whereas granule C/PL and eta37 had changed minimally. Cholesterol-rich platelets and subcellular fractions had a lower fusion (or flow) activation energy for viscosity (deltaE), reflecting a higher degree of order, and the converse was true in cholesterol-poor platelets. Moreover, a strong negative correlation existed between the percent change in deltaE and the percent change in eta37 induced either by cholesterol incorporation or depletion. These data demonstrate that cholesterol influences the fluidity and the degree of order within the hydrophobic core of platelet membranes. Changes induced in these physical properties by an excess of cholesterol relative to phospholipid may underlie the abnormal reception or transmission of the aggregation stimulus in cholesterol-rich platelets.     

Modeling mental navigation in scenes with multiple objects

Various lines of evidence indicate that animals process spatial information regarding object locations differently from spatial information regarding environmental boundaries or landmarks. Following Wang and Spelke's (2002) observation that spatial updating of egocentric representations appears to lie at the heart of many navigational tasks in many species, including humans, we postulate a neural circuit that can support this computation in parietal cortex, assuming that egocentric representations of multiple objects can be maintained in prefrontal cortex in spatial working memory (not simulated here). Our method is a generalization of an earlier model by Droulez and Berthoz (1991), with extensions to support observer rotation. We can thereby simulate perspective transformation of working memory representations of object coordinates based on an egomotion signal presumed to be generated via mental navigation. This biologically plausible transformation would allow a subject to recall the locations of previously viewed objects from novel viewpoints reached via imagined, discontinuous, or disoriented displacement. Finally, we discuss how this model can account for a wide range of experimental findings regarding memory for object locations, and we present several predictions made by the model.     

Myelolipoma of the adrenal gland

We report the 14th case of myelolipoma of the adrenal gland. Recommendations for appropriate diagnostic and therapeutic methods are made. Myelolipoma of the adrenal gland is a rare non-functioning tumor composed of lipoid and hematopoietic elements. The most consistent complaint is abdominal pain caused by hemorrhage within the tumor. We identified an association with obesity and hypertension. Ultrasound combined with computed tomography is useful in diagnosis. With expanded use of these studies, myelolipoma will be recognized more frequently. Definitive diagnosis and treatment are accomplished by simple excision; radical surgery is unnecessary.     

Bile acids: co-mutagenic activity in the Salmonella-mammalian-microsome mutagenicity test: brief communication

Of 30 bile acids tested, none was mutagenic in the Salmonella-mammalian-microsome test with indicator strains G46, TA1530, TA1535, TA1536, TA1537, TA1538, TA98, or TA100. However, when lithocholic acid or one of its conjugates was tested with suboptimal amounts of 2-aminoanthracene and phenobarbital-stimulated rat liver homogenate, enhancement and co-mutagenesis were observed if TA1538 was the indicator strain.     

Consumer and sensory investigations in relation to physical/chemical aspects of cooked pork in Scandinavia

The present study addresses sensory quality and liking for pork (eight samples) varying in quality due to adrenaline injection resulting in elevated ultimate pH post-slaughter (24h), meat ageing, cooking temperature and warmed-over flavour (WOF) among consumers (n=288) in Scandinavia. The consumers preferred meat with higher pH (pH(24h)=6.0), cooked to the lowest temperature (65?°C versus 80?°C). Consumers least preferred samples with WOF described as metallic, acidic and off-flavour by a trained panel. "Elevated pH(24h) meat" cooked to 65?°C resulted in a more sweet and tender meat. Juiciness, tenderness and the absence of off-flavour were the most important characteristics for consumers' liking of pork. Consumption frequency and liking of pork were positively related. The consumers that were most satisfied with pork quality reported highest consumption frequency. Elderly people and males expressed the highest liking score and consumption frequency, respectively.     

Foundations for offshore wind turbines

An important engineering challenge of today, and a vital one for the future, is to develop and harvest alternative sources of energy. This is a firm priority in the UK, with the government setting a target of 10% of electricity from renewable sources by 2010. A component central to this commitment will be to harvest electrical power from the vast energy reserves offshore, through wind turbines or current or wave power generators. The most mature of these technologies is that of wind, as much technology transfer can be gained from onshore experience. Onshore wind farms, although supplying 'green energy', tend to provoke some objections on aesthetic grounds. These objections can be countered by locating the turbines offshore, where it will also be possible to install larger capacity turbines, thus maximizing the potential of each wind farm location. This paper explores some civil-engineering problems encountered for offshore wind turbines. A critical component is the connection of the structure to the ground, and in particular how the load applied to the structure is transferred safely to the surrounding soil. We review previous work on the design of offshore foundations, and then present some simple design calculations for sizing foundations and structures appropriate to the wind-turbine problem. We examine the deficiencies in the current design approaches, and the research currently under way to overcome these deficiencies. Designs must be improved so that these alternative energy sources can compete economically with traditional energy suppliers.