FGF signalling is required for differentiation-induced cytoskeletal reorganisation and formation of actin-based processes by podocytes

To examine the potential role of fibroblast growth factor (FGF) signalling during cell differentiation, we used conditionally immortalised podocyte cells isolated from kidneys of Fgf2 mutant and wild-type mice. Wild-type mouse podocyte cells upregulate FGF2 expression when differentiating in culture, as do maturing podocytes in vivo. Differentiating wild-type mouse podocyte cells undergo an epithelial to mesenchymal-like transition, reorganise their actin cytoskeleton and extend actin-based cellular processes; all of these activities are similar to the activity of podocytes in vivo. Molecular analysis of Fgf2 mutant mouse podocyte cells reveals a general disruption of FGF signalling as expression of Fgf7 and Fgf10 are also downregulated. These FGF mutant mouse podocyte cells in culture fail to activate mesenchymal markers and their post-mitotic differentiation is blocked. Furthermore, mutant mouse podocyte cells in culture fail to reorganise their actin cytoskeleton and form actin-based cellular processes. These studies show that FGF signalling is required by cultured podocytes to undergo the epithelial to mesenchymal-like changes necessary for terminal differentiation. Together with other studies, these results point to a general role for FGF signalling in regulating cell differentiation and formation of actin-based cellular processes during morphogenesis.

Delayed gastric emptying in ventilated critically ill patients: measurement by 13 C-octanoic acid breath test

OBJECTIVE

To measure gastric emptying in ventilated critically ill patients with a new noninvasive breath test.

DESIGN

Single-center, open study.

SETTING

Combined medical and surgical intensive care unit of a university hospital.

SUBJECTS

Thirty unselected mechanically ventilated critically ill patients receiving gastric feeding and 22 healthy volunteers.

INTERVENTIONS

None.

PATIENTS

After 4 hrs without feeding, intragastric infusion of 100 mL of a liquid meal (Ensure) labeled with 100 microL 13C-octanoic acid. End-expiratory breath samples were collected into evacuated tubes from the respirator circuit every 5 mins for the first hour, then every 15 mins for 3 hrs. End-expiratory breath samples were also collected from volunteers studied supine after an overnight fast following an identical infusion via a nasogastric tube. Breath 13CO2 was measured with an isotope ratio mass spectrometer.

MEASUREMENTS AND MAIN RESULTS

Performance of the breath test posed no difficulty or interference with patient care. The CO2 level was >1% in 1297/1300 breath samples, indicating satisfactory end-expiratory timing. Data are median and interquartile range. Gastric emptying was slower in patients compared with volunteers: gastric emptying coefficient 2.93 (2.17-3.39) vs. 3.58 (3.18-3.79), p <.001 and gastric half emptying time, derived from the area under the 13CO2 curve, 155 min (130-220) vs. 133 min (120-145), p <.008. Fourteen of the 30 patients had a gastric emptying coefficient <95% of all volunteers and 11 had a gastric half emptying time longer than 95% of all volunteers. The Acute Physiology and Chronic Health Evaluation (APACHE II) score (median 22, range 13-43) either at admission or on the day of the study did not correlate with gastric emptying coefficient.

CONCLUSION

Gastric emptying of a calorie-dense liquid meal is slow in 40% to 45% of unselected mechanically ventilated patients in a combined medical and surgical intensive care unit. The 13C-octanoic acid breath test is a novel and useful bedside technique to measure gastric emptying in these patients.

Aids to quitting tobacco use: how important are they outside controlled trials?

BACKGROUND

Although there is good evidence that several pharmacotherapies and counseling can effectively facilitate smoking cessation, there is little information about the use or effectiveness of these or any other quit aids outside of controlled trials.

METHODS

A mailed survey with phone follow-up documented the use of various quit aids among 3,122 health plan members who smoke. A multilevel statistical modeling technique controlled for potentially confounding variables.

RESULTS

Nearly half (1,513) of these smokers reported a quit attempt during the preceding 6 months. Although 1,036 (33.2%) reported using some type of aid to quitting, primarily nicotine products or bupropion, 10-26% of these "users" did not report an actual quit attempt. Ninety percent of the medication users had a personal cost, averaging $53-$87. Fully 26.9% of those reporting a quit without any type of aid quit for at least 7 days. This rate equals that of users of all types of aids except for nicotine patches and bupropion, both of which had associated 7 or more day quit rates of about 46% (95% CI 39.3-52.2).

CONCLUSIONS

Pharmacotherapeutic quit aids are being widely used, even in the absence of significant insurance coverage.

Relationship between straining, transient lower esophageal sphincter relaxation, and gastroesophageal reflux in children

OBJECTIVE

Physical straining such as deep inspiration or coughing may induce gastroesophageal reflux (GER) by overcoming feeble lower esophageal sphincter (LES) pressure. The role of straining as a provocant of GER has not been analyzed systematically in children. It was our aim to examine the contribution of straining to the occurrence of GER with particular attention to its relationship to transient LES relaxations, which are a major mechanism of the occurrence of GER in pediatric patients.

METHODS

Concurrent esophageal manometry and pH monitoring was performed for 4 h postprandially in six children with esophagitis (age 9 months to 12 yr). Analysis was performed on isolated single strain episodes, defined as an increased intragastric pressure > 10 mm Hg. When a drop of esophageal pH < 4.0 was noted within 15 sec after any part of a strain, this strain was defined as related to the reflux episode.

RESULTS

The median value of basal LES pressure was 10 mm Hg (range 1-18). In all, 134 analyzable strains and 87 analyzable reflux episodes were recorded. Isolated strains were associated with 20 reflux episodes (23%). Reflux was observed more frequently with strains that occurred during transient LES relaxations (12/40) than straining when the LES was contracted (8/94) (p < 0.01). Sustained strain (35%) and inspiratory strain (25%) were the major patterns of straining related to reflux.

CONCLUSION

Straining provoked reflux infrequently and simultaneous occurrence of straining and transient LES relaxation was important in determining the occurrence of strain-related reflux in pediatric patients with reflux esophagitis.

An XAS investigation of product and inhibitor complexes of Ni-containing GlxI from Escherichia coli: mechanistic implications

Escherichia coli glyoxalase I (GlxI) is a metalloisomerase that is maximally activated by Ni(2+), unlike other known GlxI enzymes which are active with Zn(2+). The metal is coordinated by two aqua ligands, two histidines (5 and 74), and two glutamates (56 and 122). The mechanism of E. coli Ni-GlxI was investigated by analyzing Ni K-edge X-ray absorption spectroscopic (XAS) data obtained from the enzyme and complexes formed with the product, S-D-lactoylglutathione, and various inhibitors. The analysis of X-ray absorption near edge structure (XANES) was used to determine the coordination number and geometry of the Ni site in the various Ni-GlxI complexes. Metric details of the Ni site structure were obtained from the analysis of extended X-ray absorption fine structure (EXAFS). Interaction of S-D-lactoylglutathione (product) or octylglutathione with the enzyme did not change the structure of the Ni site. However, analysis of XAS data obtained from a complex formed with a peptide hydroxamate bound to Ni-GlxI is consistent with this inhibitor binding to the Ni center by displacement of both water molecules. XANES analysis of this complex is best fit with a five-coordinate metal and, given the fact that both histidine ligands are retained, suggests the loss of a glutamate ligand. The loss of a glutamate ligand would preserve the neutral charge on the Ni complex and is consistent with the lack of a significant shift in the Ni K-edge energy in this complex. These data are compared with data obtained from the E. coli Ni-GlxI selenomethionine-substituted enzyme. The replacement of three methionine residues in the native enzyme with selenomethionine does not affect the structure of the Ni site. However, addition of the peptide hydroxamate inhibitor leads to the formation of a complex whose structure as determined by XAS analysis is consistent with inhibitor binding via displacement of both water molecules but retention of both histidine and glutamate ligands. This leads to an anionic complex, which is consistent with an observed 1.7 eV decrease in the Ni K-edge energy. Plausible reaction mechanisms for Ni-GlxI are discussed in light of the structural information available.

Patient satisfaction and discussion of smoking cessation during clinical visits

OBJECTIVE

To learn whether patients who smoke and who receive smoking cessation information during medical office visits were less likely to be satisfied with the smoking cessation help they received than patients who smoke but who did not receive such information.

PATIENTS AND METHODS

A total of 3703 current cigarette smokers were identified by a mailing in November 1998 to 163,596 members of 2 Minnesota health plans, and 2714 (77.3%) responses to a 44-item questionnaire were available for analysis. Using hierarchical analysis to control confounding variables, we assessed the relationship between patient-reported smoking cessation support actions at the last physician visit and satisfaction "with the help received from your doctor about quitting smoking."

RESULTS

Smokers were very satisfied (12.0%), satisfied (25.3%), neutral (48.6%), and dissatisfied or very dissatisfied (13.5%) with physician help. After controlling for other characteristics, the 1898 patients who reported that they had been asked about tobacco use or advised to quit during the latest visit had 10 percentage point greater satisfaction ratings and 5 percentage point less dissatisfaction than those not reporting such discussions (P<.001). Smokers reporting no interest in quitting at the time of the latest visit also demonstrated greater satisfaction in association with these actions.

CONCLUSION

Smoking cessation interventions during physician visits were associated with increased patient satisfaction with their care among those who smoke. This information should reduce concerns of physicians or nurses about providing tobacco cessation assistance to patients during office visits.

Determination of pesticides in soil samples by supercritical fluid chromatography-atmospheric pressure chemical ionisation mass spectrometric detection

This paper presents an analytical technique for the determination of pesticides in soil by packed-column supercritical fluid chromatography interfaced with atmospheric pressure chemical ionisation mass spectrometry (pSFC-APCI-MS). The technique provides a versatile method for the detection and quantification of pesticides belonging to three different commonly used classes, triazines (ametryne, atrazine), carbamates (carbofuran) and sulfonylureas (chlorsulfuron, metsulfuron methyl and benzsulfuron methyl). The APCI mass spectra for all the pesticides studied consisted of protonated molecule ions as the most abundant ion at low cone voltages, except for metsulfuron methyl and benzsulfuron methyl, which gave a fragment ion as the most abundant ion with the protonated molecule ion at low intensity. Increasing the cone voltage provided informative fragmentation patterns for all species. The technique shows good linearity over the concentration range of 0.1-50 micrograms ml-1, with r2 values as follows: atrazine 0.997, ametryne 0.995, carbofuran 0.999, benzsulfuron methyl 0.999, chlorsulfuron 0.995 and metsulfuron methyl 0.997. The detection limits in the selected ion mode were atrazine 201, ametryne 144 and carbofuran 385 pg, which were calculated by using the standard solution, and benzsulfuron methyl 2.045, chlorsulfuron 1.435 and metsulfuron methyl 2.414 ng, which were determined by using spiked soil samples. The pSFC-MS system was shown to have a high degree of reproducibility. The technique was then applied to the determination of the above pesticides in soil samples. The results obtained show that there is no matrix effect from the soil and that the detection limits for all pesticides in soil were similar to those found for the standard solutions.

Development of a packed-column supercritical fluid chromatography/atmospheric pressure chemical-ionisation mass spectrometric technique for the analysis of atropine

A packed-column supercritical fluid chromatography/atmospheric pressure chemical-ionisation mass spectrometry (pSFC-APCI/MS) method has been developed for the determination of atropine from Atropa belladonna L extracts. The technique does not require any kind of derivatisation prior to the analysis. The optimum conditions were studied by using the pure substance in methanol (MeOH). All samples were simply dissolved in MeOH and injected into the mobile phase. Detection was achieved by using mass spectrometry (MS) with atmospheric pressure chemical ionisation (APCI). Terbutaline was used as an internal standard for the determination of the analytical reproducibility. The supercritical carbon dioxide (scCO(2)) mobile phase was modified by 15% MeOH containing 0.5% trifluoroacetic acid (TFAA) and 0.5% diethylamine (DEA) additives. Concentrations of atropine were determined with a relative standard deviation of less than 1% by the pSFC-APCI/MS procedure for a sample containing atropine and terbutaline. The correlation coefficient was 0.997 and detection limit 700 pg. The absolute retention time was 9.87 min with a standard deviation of 5.2x10(-3) min and a relative standard deviation of 0.61% with respect to terbutaline.

SFC/FTIR, SFC/APCI-MS and MALDI-TOF-MS for the analysis of siloxane-ethylene oxide copolymers

Polydimethylsiloxanes (PDMSs) modified by introducing ethylene oxide units with the aim of forming sufficiently water-soluble siloxane compounds were characterized using supercritical fluid chromatography (SFC) coupled with Fourier transform infrared (FTIR) spectroscopy and atmospheric pressure chemical ionization mass spectrometry (APCI-MS), and matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF-MS). SFC has a domain in analyzing oligomers. Hyphenated techniques enable elucidation of the components. Remarkable is the resolution and short analysis time of MALDI-TOF-MS. SFC also allows quantification of the basic and reaction products.

Determination of sulfonamides by packed column supercritical fluid chromatography with atmospheric pressure chemical ionisation mass spectrometric detection

Sulfonamide antibiotics are widely used to prevent bacterial infections in livestock, and residues are commonly found in milk and meat. Packed column supercritical fluid chromatography (pSFC) with detection using ultra violet (UV) and atmospheric pressure chemical ionisation (APCI) mass spectrometry (MS) provides a versatile method for the detection and quantification of six major sulfonamides. The APCI mass spectra for all the sulfonamides consisted of protonated molecules at low cone voltages. Increasing the cone voltage led to informative fragmentation patterns, which provided structural information for identification purposes. The pSFC-APCI-MS technique was shown to be linear (r2 > or = 0.999) over the concentration range 0.1-50 micrograms ml-1 using total ion current. The precision and the accuracy of the system and validation of sample preparation are acceptable, with RSD < 2% and relative error 8%. Selected ion monitoring gave detection limits as follows: sulfadiazine 41, sulfamethoxazole 45, sulfamerazine 47, sulfamethizole 59, sulfamethazine 181 and sulfadimethoxine 96 micrograms l-1, which are lower than the amounts permitted in milk products. The APCI pSFC-MS system was shown to have a high degree of reproducibility. The technique was then applied to determine the above sulfonamides in milk. The results obtained show that there are no matrix effects from the milk and that the detection limits remained as stated for the standard solutions.

Structural examination of the nickel site in chromatium vinosum hydrogenase: redox state oscillations and structural changes accompanying reductive activation and CO binding

An X-ray absorption spectroscopic study of structural changes occurring at the Ni site of Chromatium vinosum hydrogenase during reductive activation, CO binding, and photolysis is presented. Structural details of the Ni sites for the ready silent intermediate state, SI(r), and the carbon monoxide complex, SI-CO, are presented for the first time in any hydrogenase. Analysis of nickel K-edge energy shifts in redox-related samples reveals that reductive activation is accompanied by an oscillation in the electron density of the Ni site involving formally Ni(III) and Ni(II), where all the EPR-active states (forms A, B, and C) are formally Ni(III), and the EPR-silent states are formally Ni(II). Analysis of XANES shows that the Ni site undergoes changes in the coordination number and geometry that are consistent with five-coordinate Ni sites in forms A, B, and SI(u); distorted four-coordinate sites in SI(r) and R; and a six-coordinate Ni site in form C. EXAFS analysis reveals that the loss of a short Ni-O bond accounts for the change in coordination number from five to four that accompanies formation of SI(r). A shortening of the Ni-Fe distance from 2.85(5) A in form B to 2.60(5) A also occurs at the SI level and is thus associated with the loss of the bridging O-donor ligand in the active site. Multiple-scattering analysis of the EXAFS data for the SI-CO complex reveals the presence of Ni-CO ligation, where the CO is bound in a linear fashion appropriate for a terminal ligand. The putative role of form C in binding H(2) or H(-) was examined by comparing the XAS data from form C with that of its photoproduct, form L. The data rule out the suggestion that the increase in charge density on the NiFe active site that accompanies the photoprocess results in a two-electron reduction of the Ni site [Ni(III) --> Ni(I)] [Happe, R. P., Roseboom, W., and Albracht, S. P. J. (1999) Eur. J. Biochem. 259, 602-608]; only subtle structural differences between the Ni sites were observed.

Randomized trial of omeprazole and metronidazole with amoxycillin or clarithromycin for Helicobacter pylori eradication, in a region of high primary metronidazole resistance: the HERO study

BACKGROUND

The efficacy of omeprazole-based eradication therapies has been determined mostly in populations with low to moderate prevalence of metronidazole resistant Helicobacter pylori, yet resistance is high in many regions.

AIM AND METHODS

The H. pylori eradication and duodenal ulcer healing rates after 1 week of either omeprazole 40 mg mane, amoxycillin 500 mg t.d.s. and metronidazole 400 mg t.d.s. (OAM) or omeprazole 20 mg b.d., metronidazole 400 mg b. d. and clarithromycin 250 mg b.d. (OMC) were compared in a randomized trial in Australia and New Zealand. Patients had a further 1 week of omeprazole 20 mg. Outcome was assessed at 6 weeks with stringent criteria (endoscopy, biopsies and 13C-urea breath test).

RESULTS

Of 220 subjects randomized, the H. pylori eradication rates (all patients treated/per protocol) were 82%/85% for OMC and 58%/63% for OAM (P= 0.001). Pre-treatment metronidazole resistance was present in 56% and clarithromycin resistance in 6%. The eradication rate for primary metronidazole resistance isolates treated with OMC was 80% (CI: 65-90%) compared with 45% (CI: 29-62%) for OAM, whereas for sensitive organisms, the eradication rates were 94% (CI: 79-99%) and 79% (CI: 62-91%), respectively. Duodenal ulcer healing was 96% for OMC and 87% for OAM. Compliance was excellent and both treatments were well-tolerated.

CONCLUSIONS

OMC is a well-tolerated, effective therapy for H. pylori eradication and duodenal ulcer healing in this region despite the high metronidazole resistance rate. OAM is less effective, largely due to the impact of metronidazole resistance.

Characterization of varietal differences in essential oil components of hops (Humulus lupulus) by SFC-FTIR spectroscopy

A supercritical fluid chromatographic method combined with Fourier-transform infrared spectroscopy detection (SFC-FTIR) was developed for determination of varietal differences in essential oil constituents in hops (Humulus lupulus). Infrared spectra (IR) of the major constituents of essential oil of hops were taken as films deposited on AgCl discs and compared with those obtained after chromatographic separation in the IR flow-cell with supercritical carbon dioxide (scCO2). Spectra from AgCl discs were comparable to those in scCO2, but in scCO2 most of the bands appeared approximately 8-10 cm-1 to higher wave numbers. Open-tubular SFC-FTIR analysis of the essential oil of 4 different hop varieties was performed. The SFC-FTIR chromatograms showed differences in the location and relative intensity of the peaks depending on the variety, which was further confirmed by consideration of their FTIR spectra.

Failure of a continuous quality improvement intervention to increase the delivery of preventive services. A randomized trial

CONTEXT

Although there has been enormous interest in continuous quality improvement (CQI) as a measure to improve health care, this enthusiasm is based largely on its apparent success in business rather than formal evaluations in health care.

OBJECTIVE

To determine whether a managed care organization can increase delivery of eight clinical preventive services by using CQI.

DESIGN

Primary care clinics were randomly assigned to improve delivery of preventive services with CQI (intervention group) or to provide usual care (control group).

INTERVENTION

Through leadership support, training, consulting, and networking, each intervention clinic was assisted to use CQI multidisciplinary teams to develop and implement systems for delivery of preventive services.

SETTING

44 primary care clinics in greater Minneapolis-St. Paul.

PATIENTS

Patients 19 years of age and older completed surveys at baseline (n = 6830) and at follow-up (n = 6431). Medical chart audits were completed on 4777 patients at baseline and 4546 patients at follow-up.

MAIN OUTCOME MEASURES

The proportion of patients who were up-to-date (according to chart audit) and the proportion of patients who were offered a service if not up-to-date (according to patient report) for 8 preventive services.

RESULTS

Compared with the control group, based on the proportion of patients who were up-to-date, use of only one preventive service--pneumococcal vaccine--increased significantly in the intervention group (17.2% absolute increase from baseline to follow-up compared with a 0.3% absolute increase in the control group, P = 0.003). Similarly, based on patient report of being offered a service if not up-to-date, delivery of only one preventive service--cholesterol testing--significantly increased in the intervention group compared with the control group (4.6% increase vs. 0.4% absolute decrease in the control group; P = 0.006).

CONCLUSION

In this trial, CQI methods did not result in clinically important increases in preventive service delivery rates.