Effect of acute increases in filtered HCO3- on renal hydrogen transporters: II. H(+)-ATPase

Adaptive increases in renal bicarbonate reabsorption occur in response to acute increases in filtered bicarbonate (FLHCO3). In a previous study, we showed that an increase in FLHCO3 induced by plasma volume expansion increased the Vmax for Na+/H+ exchange activity in renal cortical brush border membrane vesicles (BBMV), providing a potential mechanism for the adaptive increase in HCO3- reabsorption. The present studies were undertaken to determine whether the increase in FLHCO3 induced by plasma expansion also stimulates the other major H+ transporter in cortical BBMV, the H(+)-ATPase. H(+)-ATPase activity was assessed in BBMV obtained from hydropenic and plasma expanded Munich-Wistar rats, using a NADH-linked ATPase assay. H(+)-ATPase activity was measured as the ouabain and oligomycin-insensitive, bafilomycin A1-sensitive component of total ATPase activity. Acute plasma expansion doubled single nephron FLHCO3, and this change was associated with a 64% increase in the Vmax for H(+)-ATPase activity, with no change in apparent Km. The Vmax for H(+)-ATPase activity correlated directly with whole kidney GFR and FLHCO3 (r = 0.68 and 0.72, respectively), and with single nephron GFR and FLHCO3 (r = 0.76 and 0.80, respectively). Thus, the mechanism for the adaptive increase in proximal tubular HCO3- reabsorption that occurs in response to acute increases in FLHCO3 appears to be related to increased activity of both H(+)-ATPase and Na+/H+ exchange in the apical membrane of the proximal tubule epithelium.     

The combined use of ultrasound and densitometry in the prediction of vertebral fracture

Measurement of ultrasonographic parameters provides information concerning not only bone density but also bone architecture. We investigated the usefulness of ultrasonographic parameters and bone mineral density for evaluating the probability of vertebral fracture. 397 postmenopausal women (59.1 +/- 6.0 years) with (n = 178) or without (n = 219) atraumatic vertebral fractures were studied. In all women, bone mineral density (BMD) of the lumbar spine was evaluated by dual X-ray absorptiometry (DXA) and speed of sound (SOS); broadband ultrasound attenuation (BUA) and Stiffness in the calcaneus were evaluated by an Achilles unit (Lunar Corporation). Ultrasonographic parameters and BMD were compared by examining the magnitude of the odds ratios, to determine which produces the highest estimate of the probability of odds of fracture, and by examining widths of the respective confidence intervals (CI) to show which estimate of odd ratio is the most precise. The relative risk of vertebral fracture, after adjusting for potential confounders, was 3.5 (CI 2.6-4.8) for BUA; 4.5 (CI 3.2-6.2) for SOS; 5.8 (CI 4.0-8.4) for Stiffness and 7.5 (CI 4.8-11.5) for BMD. Ultrasound (US) parameters were still significant independent predictors of vertebral fracture, even after adjusting for BMD. The relative risk of fracture for a simultaneous decrease by 1 SD of BMD and by 1 SD of each ultrasound parameter was 17.3 (CI 9.4-39.6) for BMD and SOS; 18.3 (CI 8.4-30.6) for BMD and BUA and 22.1 (CI 8.9-52.7) for BMD and Stiffness. Our data suggest that US and BMD provide complementary information which can be combined to improve estimates of vertebral fracture risk.     

Oxidation and Fracture Strength of High-Purity Reaction-Bonded Silicon Nitride

Reaction-bonded Si₃N₄ (RBSN) made from high-purity Si powder is unusually resistant to degradation caused by exposures to air for up to 50 h at temperatures up to 1400°C. The weight gain during oxidation of this SiH₄-originating RBSN is approximately 10 times less than conventional RBSN. Contrary to normally observed strength degradations, room-temperature strengths of this high-purity, oxidized RBSN (avg = 435 MPa, max. = 668 MPa) remained at their unusually high, as-processed levels after 1000° and 1400°C oxidizing exposures. Fracture toughness values were unaffected by oxidation ( K _IC= 2.3 to 2.4 MPa · m^1/2). This superior oxidation resistance results from the high purity and the small diameter pore channels (0.01 to 0.06 μm) achieved in this SiH₄-originating RBSN.     

Qualitative Temporal Reasoning Can Improve on Temporal Annotation Quality: How and Why

The analysis of time helps in extracting knowledge from web contents. In order to analyze massive amounts of data, current natural language processing systems rely mainly on supervised approaches: machine learning algorithms that learn how to classify data based on corpora, annotated with the TimeML mark-up language or one of its derivatives. The quality of annotation data, thus, affects the performances of such systems. Quality can be improved by reasoning on temporal annotations. This article takes such a view. After a review of the strictly necessary background, it focuses on and discusses open issues in the area of quality of temporal annotations: inconsistency and incompleteness of annotations. Then it proposes a semantic reasoning approach as solution for improving on their quality, viz., the SOA-based Qualitative Temporal Reasoner for reasoning about temporal annotations, which leverages on existing theories and tools for qualitative reasoning. The article presents the design of the reasoner and its two main reasoning services: consistency checking for tackling inconsistency, and deduction for addressing incompleteness on demand. Afterward, the paper presents an experimental evaluation of the reasoner, sustaining why the chosen semantic reasoning approach can help improve on quality of annotations. The experiment assesses the reasoner’s performances on two different corpora and from several perspectives, e.g., the effectiveness of consistency checking in terms of the number of inconsistent documents found, and of deduction in terms of the number of annotations added. It concludes with discussion of the results of the evaluation and possible routes for future work.     

Changes in aerobic microflora of skin and gills of Mediterranean sardines (Sardina pilchardus) during storage in ice

Sardines from the Adriatic Sea were examined fresh and after 4 and 8 days of storage in ice. A total of 1500 strains isolated were identified from the gills and the surface of the fish. Pseudomonadaceae, Neisseriaceae, Flavobacterium/Cytophaga, Enterobacteriaceae, coryneform bacteria and Micrococcaceae were the most common bacteria in fresh fish. During storage the pseudomonads (mainly the non-fluorescent strains) increased and became the dominating microflora; the Neisseriaceae (Moraxella, Psychrobacter and Acinetobacter) showed a distinct increase during the first 4 days in ice; the percentage of the other bacterial groups clearly decreased. On the gills the quantitative changes in the microflora were less pronounced than on the surface.     

The guideline interchange format: a model for representing guidelines

Carboxylate and sulfate groups were introduced at the surface of poly(ethylene) (PE) samples. This was accomplished by coating and immobilizing sodium 10-undecenoate (C11(:)) and 10-undecene sulfate (S11(:)) on the polymer by means of an argon plasma treatment. The composition of the coated surfactant layer was proportional to the composition of the coating solution. The thickness of the surfactant layer on the surface of PE samples, which were precoated from an aqueous solution with a total surfactant concentration of 0.30 M, was about 55 A. The presence of carboxylate and sulfate groups after plasma treatment of the precoated surfaces was confirmed by X-ray photoelectron spectroscopy (XPS). About 20% of the initial amount of functional groups of the coated surfactants was retained at the PE surface. The ratio of carboxylate/sulfate groups at the plasma treated surfaces was dependent on the composition of the precoated surfaces. The minimum surface density of these groups on the resulting samples was about one group per 40 A2.     

Effects of surgical trauma of laparoscopic vs. open cholecystectomy

The effects of surgical trauma resulting from laparoscopic cholecystectomy and open cholecystectomy, were compared by assessing the postoperative acute phase alterations of selected plasma proteins, hormones and lymphocyte subpopulations in fifty-seven patients prior to elective cholecystectomy. Patients were prospectively randomized to undergo either laparoscopic cholecystectomy (n = 30) or open cholecystectomy (n = 27). Duration of operation and general anesthesia was similar in the two patient groups. The laparoscopic cholecystectomy patients had a shorter postoperative stay in hospital (3.1 (0.5) days vs. 7.1 (1.6) days; p < 0.001). In open cholecystectomy patients a significantly greater postoperative acute phase increase in plasma C-reactive protein (p < 0.001), cortisol (p < 0.05), and prolactin blood level (p < 0.001) was recorded. The postoperative acute phase decrease in the blood total-T-lymphocyte count (CD3 cells) and in the activated-lymphocyte count (OKDR cells) was significantly greater after open cholecystectomy (p < 0.05). These results, showing that acute phase responses are less marked after laparoscopic cholecystectomy than after open cholecystectomy, support the concept that the laparoscopic procedure is less traumatic.