Tn916 transposition in Haemophilus influenzae Rd: preferential insertion into noncoding DNA

OBJECTIVES: A low level of education is associated with an increased risk of developing a dementia disorder, as well as with a higher risk of cardiovascular disease. The aim of this study was to investigate the association between education and cardiovascular risk factors, and to study the relation between these factors and cognitive function in elderly men. DESIGN: Cross-sectional population-based study. SETTING: Uppsala, Sweden. SUBJECTS: 504 men aged 69-74 years, participants in a longitudinal health survey concerning cardiovascular risk factors. MAIN OUTCOME MEASURE: Cognitive function as measured by a composite score of 13 standard psychometric tests. RESULTS: A low level of education was associated with poorer cognitive performance, as well as with obesity, smoking, diabetes, high concentrations of serum triglycerides and plasma fibrinogen. In the entire cohort, subjects with obesity, smoking, diabetes or hypertriglyceridaemia showed impaired cognitive test results, independent of socio-economic factors. When stroke cases were excluded, obesity and smoking were still related to impaired cognitive function. CONCLUSIONS: Smoking and obesity with associated metabolic disturbances are inversely related both to educational level and to cognitive function. Cognitive decline of vascular origin is potentially preventable by treatment of risk factors. The question of whether the increased vascular risk contributes to the higher prevalence of cognitive disorders in individuals with low socio-economic status, needs to be further evaluated in longitudinal population-based studies.     

Confocal microscopy of human lens membranes in aged normal and nuclear cataracts

PURPOSE: To visualize the structure and determine the continuity of lipid membranes in lens fiber cells (LFCs) from human aged normal and cataractous lenses. METHODS: Thick sections from human nuclear cataracts and aged normal lenses were stained with the lipophilic probe DiI, and then analyzed by confocal microscopy. Staining patterns of membranes were observed in individual optical sections or three-dimensional projections of z-series taken in longitudinal section and cross-section of LFCs from different regions within the lens nucleus. RESULTS: DiI bound to and delineated the plasma membrane of LFCs from all regions of the lens nucleus. Three-dimensional projections of z-series from aged normal and cataractous lenses suggested that some of the stained lipid membranes were not continuous with LFC plasma membrane of cataractous lenses. CONCLUSIONS: The results obtained using these methods demonstrated that lipid membranes, discontinuous with the plasma membrane of LFCs, were indicative of a novel process occurring predominately in cataractous human lenses.     

The role of thyroid resection during reoperation for persistent or recurrent hyperparathyroidism

BACKGROUND: The role of "blind" thyroid lobectomy in the surgical management of patients with persistent or recurrent primary hyperparathyroidism is not known. We reviewed our experience with reoperation for hyperparathyroidism to determine the utility of blind thyroid resection in this setting. METHODS: From 1982 to 1995, 269 patients underwent reoperation for hyperparathyroidism at our institution. All patients had biochemical confirmation of hyperparathyroidism and underwent noninvasive and if necessary invasive localization studies. Patients who underwent thyroid lobectomy in an attempt to extirpate the hyperfunctioning parathyroid gland form the basis of this report. RESULTS: Thirty-two of 269 patients (12%) underwent thyroid lobectomy to remove a parathyroid gland. Intrathyroidal parathyroids were confirmed in 19 of 32 patients (59%). In 18 of 19 patients (94%), preoperative or intraoperative ultrasonography correctly identified an intrathyroidal lesion suspicious or a parathyroid. Only 1 of 6 patients (17%) undergoing a blind thyroidectomy had an intrathyroidal gland identified. Ultrasonography had a sensitivity of 95% and a negative predictive value of 99.5% in detecting an intrathyroidal parathyroid gland. CONCLUSIONS: The prevalence of an intrathyroidal parathyroid gland in our series is low (19 of 269, 7%). Ultrasonography can be used reliably to select patients for thyroid resection, reducing the need to perform a blind thyroid lobectomy and avoiding the potential morbidity of thyroid resection in this clinical setting.     

Genetically engineered metal ion binding sites on the outside of a Channel's transmembrane beta-barrel

We are exploring the ability of genetically engineered versions of the Staphylococcus aureus alpha-hemolysin (alphaHL) ion channel to serve as rationally designed sensor components for analytes including divalent cations. We show here that neither the hemolytic activity nor the single channel current of wild-type alphaHL was affected by [Zn(II)] 相似文献   

The effect of pre‐coking on the activity and selectivity of the catalytic cracking of squalane

The pre‐coking of cracking catalysts has been reported to increase the yield of light cycle oil from fluid catalytic cracking. The present studies investigating an equilibrated catalyst show that this is not the case. The effect of pre‐treating equilibrated catalysts with coke and with ammonia shows that conversion was decreased in both cases and the product selectivity of the process changed. Both coke and ammonia were found to decrease site density, reducing the importance of hydrogen transfer reactions. Increased yields of light cycle oil as a result of pre‐coking can only be expected with fresh catalyst, where small amounts of coke deactivate the most acidic sites. Such sites have already been deactivated on equilibrated catalyst. Copyright © 2004 Society of Chemical Industry     

Morbidity and mortality in cirrhotic patients undergoing anesthesia and surgery

The concept and design of a cemented unconstrained total shoulder arthroplasty (TSA), introduced by Charles Neer II 25 years ago, has been successful in the management of degenerative and inflammatory conditions of the shoulder, controlling pain and, in many patients, significantly improving function. The clinical outcome is very much determined by the nature and severity of the pathology, as well as by the surgeon's experience and ability to correctly locate and fix the components. Total shoulder arthroplasty is a technically difficult procedure with perhaps a greater potential for technical errors and complications compared with other commonly performed arthroplasties. Current systems are modular on the humeral side, with varying head diameters and neck lengths, allowing more accurate coverage of the cut surface of the humeral neck and improved ability to establish the position of the joint line within the requirements of correct soft tissue tension and balance. Cemented all-polyethylene glenoid components remain the most favored, but the majority now have an increased radius of curvature compared with their corresponding humeral head, to allow translation during movement. Aseptic glenoid component loosening is the most frequently encountered long-term complication and is hastened by conforming prostheses, incorrect positioning, rotator cuff tears, and capsular contractures, but is protected by secure glenoid fixation. Cemented one-piece metal-backed glenoids have been disappointing, but non-cemented glenoids are being trialed with promising early results, although they have introduced their own particular problems of rapid polyethylene wear and component dissociation. Although cemented humeral components have a very low incidence of symptomatic loosening, most surgeons currently use press-fit designs supplemented with metaphyseal porous coating for osseous integration. Based on increased understanding of the morphology of the upper humerus, current designs are evolving with increased modularity, allowing the surgeon to choose the appropriate size, inclination, offset and version of the humeral component. These changes will, it is hoped, result in improved functional recovery and increased survivorship of the glenoid component.     

Intracerebral sources of human auditory-evoked potentials

Evoked potentials to brief 1,000-Hz tones presented to either the left or the right ear were recorded from 30 electrodes arrayed over the head. These recordings were submitted to two different forms of source analysis: brain electric source analysis (BESA) and variable-resolution electromagnetic tomography (VARETA). Both analyses showed that the dominant intracerebral sources for the late auditory-evoked potentials (50-300 ms) were in the supratemporal plane and lateral temporal lobe contralateral to the ear of stimulation. The analyses also suggested the possibility of additional sources in the frontal lobes.     

Hydroxide rather than histidine is coordinated to the heme in five-coordinate ferric Scapharca inaequivalvis hemoglobin

The ferric form of the homodimeric Scapharca hemoglobin undergoes a pH-dependent spin transition of the heme iron. The transition can also be modulated by the presence of salt. From our earlier studies it was shown that three distinct species are populated in the pH range 6-9. At acidic pH, a low-spin six-coordinate structure predominates. At neutral and at alkaline pHs, in addition to a small population of a hexacoordinate high-spin species, a pentacoordinate species is significantly populated. Isotope difference spectra clearly show that the heme group in the latter species has a hydroxide ligand and thereby is not coordinated by the proximal histidine. The stretching frequency of the Fe-OH moiety is 578 cm-1 and shifts to 553 cm-1 in H218O, as would be expected for a Fe-OH unit. On the other hand, the ferrous form of the protein shows substantial stability over a wide pH range. These observations suggest that Scapharca hemoglobin has a unique heme structure that undergoes substantial redox-dependent rearrangements that stabilize the Fe-proximal histidine bond in the functional deoxy form of the protein but not in the ferric form.     

Acto-myosin drug effects and aqueous outflow function

PURPOSE: The ability of aerobic exercise to change lymphocyte subpopulation distributions is well documented; much less is known about resistance exercise. The purpose of this experiment was to determine the effects of an acute bout of resistance exercise on lymphocyte subpopulations in primary and secondary lymphoid compartments. METHODS: Male rats were operantly conditioned to climb a ladder while carrying weights that were progressively increased to equal body weight. During the acute session, rats performed repetitive climbs until exhaustion. Thymus, spleen, blood, and axial and inguinal lymph nodes were removed; leukocytes were isolated and incubated with monoclonal antibodies against differentiation markers, activation antigens, and adhesion molecules. RESULTS: Exercised versus control rats had greater numbers of leukocytes in the thymus, axial, and inguinal nodes but not in the blood or spleen. The percentage of CD4+ cells increased after exercise in the thymus, spleen, and blood. The percentages of cells expressing the integrin LFA-1beta were elevated in all the tissues except inguinal lymph nodes. In addition, more leukocytes from exercised than nonexercised rats expressed detectable numbers of activation markers, IL-2 receptor-alpha and MHC class II molecules; however, as indicated by proliferating cell nuclear antigen analysis, the cells were not actively dividing at the time of assay. CONCLUSIONS: Based on these and published data, it appears that a single bout of resistance exercise can affect lymphoid cell subpopulations probably by inducing changes in leukocyte trafficking.     

Evaluation of enterolithiasis in equids: 900 cases (1973-1996)

In this study we investigated the effect of lesioning the noradrenergic systems on the behavioral effects of (5R, 10S)-(+)-5-Methyl-10,11-dihydro-5H-dibenzo [a, d] cyclohepten-5,10-imine hydrogen maleate--MK-801, in rats. The noradrenergic system was lesioned with N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride--DSP4 (60 mg/kg IP). MK-801 increased the locomotor activity and rearing. DSP4 significantly further increased the hyperlocomotor activity, circling (especially to the left side), sniffing, rolling, and falling that were induced by MK-801. These results showed that destruction of the noradrenergic system increased MK-801-hyperlocomotor activity, ataxia and stereotypy.