rac-1-[(2-Methoxyethyl)sulfanyl]-2-[(2-methoxyethyl)sulfinyl]benzene and its PdCl2 complex.

As an extension of recent findings on the recovery of palladium with dithioether extractants, single crystals of the chelating vicinal thioether sulfoxide ligand rac-1-[(2-methoxyethyl)sulfanyl]-2-[(2-methoxyethyl)sulfinyl]benzene, C(12)H(18)O(3)S(2), (I), and its square-planar dichloridopalladium complex, rac-dichlorido{1-[(2-methoxyethyl)sulfanyl]-2-[(2-methoxyethyl)sulfinyl]benzene-κ(2)S,S'}palladium(II), [PdCl(2)(C(12)H(18)O(3)S(2))], (II), have been synthesized and their structures analysed. The molecular structure of (II) is the first ever characterized involving a dihalogenide-Pd(II) complex in which the palladium is bonded to both a thioether and a sulfoxide functional group. The structural and stereochemical characteristics of the ligand are compared with those of the analogous dithioether compound [Traeger et al. (2012). Eur. J. Inorg. Chem. pp. 2341-2352]. The sulfinyl O atom suppresses the electron-pushing and mesomeric effect of the S-C-C-S unit in ligand (I), resulting in bond lengths significantly different than in the dithioether reference compound. In contrast, in complex (II), those bond lengths are nearly the same as in the analogous dithioether complex. As observed previously, there is an interaction between the central Pd(II) atom and the O atom that is situated above the plane.

Role of sensory nerves in the cutaneous vasoconstrictor response to local cooling in humans.

Local cooling (LC) causes a cutaneous vasoconstriction (VC). In this study, we tested whether there is a mechanism that links LC to VC nerve function via sensory nerves. Six subjects participated. Local skin and body temperatures were controlled with Peltier probe holders and water-perfused suits, respectively. Skin blood flow at four forearm sites was monitored by laser-Doppler flowmetry with the following treatments: untreated control, pretreatment with local anesthesia (LA) blocking sensory nerve function, pretreatment with bretylium tosylate (BT) blocking VC nerve function, and pretreatment with both LA and BT. Local skin temperature was slowly reduced from 34 to 29 degrees C at all four sites. Both sites treated with LA produced an increase in cutaneous vascular conductance (CVC) early in the LC process (64 +/- 55%, LA only; 42 +/- 14% LA plus BT; P < 0.05), which was absent at the control and BT-only sites (5 +/- 8 and 6 +/- 8%, respectively; P > 0.05). As cooling continued, there were significant reductions in CVC at all sites (P < 0.05). At control and LA-only sites, CVC decreased by 39 +/- 4 and 46 +/- 8% of the original baseline values, which were significantly (P < 0.05) more than the reductions in CVC at the sites treated with BT and BT plus LA (-26 +/- 8 and -22 +/- 6%). Because LA affected only the short-term response to LC, either alone or in the presence of BT, we conclude that sensory nerves are involved early in the VC response to LC, but not for either adrenergic or nonadrenergic VC with longer term LC.

Short daily hemodialysis rapidly improves nutritional status in hemodialysis patients.

BACKGROUND: Malnutrition is a common problem in maintenance hemodialysis patients and is associated with increased mortality and morbidity. Interventions such as oral or intravenous nutritional supplements have often failed to improve nutritional status. We studied the effect of a daily dialysis program on nutritional parameters. METHODS: Eight patients treated with standard hemodialysis (SHD) 4 to 5 hours three times per week were converted to daily hemodialysis (DHD) 2 to 2.5 hours six times per week. Serum albumin, prealbumin, and total cholesterol were evaluated every three months. Anthropometry and dietary evaluation were performed every six months. RESULTS: Serum albumin rose from 39.0 +/- 2.6 to 42.0 +/- 3.1 and 43.0 +/- 2.6 g/L, prealbumin from 0.36 +/- 0.04 to 0.41 +/- 0.05 and 0.42 +/- 0.1 g/L, total cholesterol from 1.7 +/- 0.4 to 1.9 +/- 0.4 and 1.8 +/-0.3 g/L at baseline and at 6 and 12 months, respectively, after switching patients to DHD. Daily protein intake increased from 1.29 +/- 0.20 g/kg/day to 1.48 +/- 0.60 and 1.90 +/- 0.70 (P < 0.05). These changes were accompanied by a dry body weight increase of 2.4 +/- 1.6 kg (P < 0.005) at month 6 and 4.2 +/- 2.8 kg at one year (P < 0.05). Lean body mass increased from 47.7 +/- 4.9 kg to 49.1 +/- 5.9 (P < 0.05) and 50.5 +/- 6.2 (P < 0.05). CONCLUSIONS: Daily hemodialysis appears to be a suitable method to improve nutritional status in maintenance dialysis patients.

Short daily hemodialysis and nutritional status.

Daily hemodialysis improves clinical outcomes in dialysis patients. This study shows the results of 10 patients who underwent short daily hemodialysis (SDHD) from 23.2 +/- 13 months and focuses on nutritional status under this strategy. With SDHD, patients had an increase in energy and protein intake confirmed by an increase in dry weight and lean body mass. Additional clinical improvement was obtained for blood pressure control, regression of left ventricular hypertrophy, correction of anemia, and better quality of life. These biological and clinical improvements are mainly the results of a higher frequency of dialysis sessions. The nutritional improvements with disappearance of anorexia are the consequence of general well being, less dietetic constraints, and less drugs prescribed. Short daily hemodialysis offers an adequate and more physiological strategy and may be considered for improving nutritional status in selected patients.

Twenty-five years of experience with out-center hemodialysis.

UNLABELLED: Twenty-five years of experience with out-center hemodialysis. BACKGROUND: Out-center hemodialysis (HD) offers patients a better quality of life, a greater independence, and a better rehabilitation opportunity. A lower mortality than with other modalities of dialysis has been reported. In addition, in France the charges paid depend on the modality of dialysis, out-center HD being the less expensive, and savings are also accomplished through fewer patient transports, which are additionally reimbursed. We present a 25-year experience of out-center HD. METHODS: We retrospectively studied the clinical records of 471 patients treated between 1974 and 1997 in a single nonprofit organization operating regional home HD (H-HD) and facilities for self-care HD (SC-HD). Survival results were analyzed according to: (a) causes of end-stage renal disease, (b) age at the start of HD, (c) period of start of HD, (d) modality of HD (H-HD, SC-HD), and (e) a subgroup of 174 patients defined at risk because they were contraindicated for transplantation. RESULTS: The mean age at the start of HD increased from 31.2 +/- 9.7 (mean +/- SD) years in 1974 to 52.6 +/- 13.5 years in 1997. Causes of the end of treatment were: (a) transplantation (63%), (b) transfer (20%), and (c) death (17%). The overall survival was 90% at 5 years, 77% at 10 years, 62% at 15 years, and 45% at 20 years, and, for the group at risk, 78%, 62%, 46%, and 31%, respectively. Cox proportional hazard analyses showed that risk factors were older age, diabetes, and renal vascular diseases. CONCLUSION: If adequate choice is given, out-center HD offers a reliable and safe modality of dialysis with better survival results than survival in full-care in-center HD. In addition, out-center HD ensures a striking financial benefit as compared with the higher costs if the same patients were treated with full-care in-center HD. These modalities should be encouraged for all HD patients who are able to be treated by out-center modalities.

Peritoneal clearance of leptin in continuous ambulatory peritoneal dialysis.

Leptin is a 16-kd protein that increases energy expenditure and limits food intake. Serum leptin (S-leptin) is elevated in dialysis patients, and little data have been reported on leptin clearance (Cl) during dialysis. We analyzed the peritoneal dialysis (PD) Cl of leptin in 15 continuous ambulatory peritoneal dialysis (CAPD) patients and compared the results to beta(2)-microglobulin (beta(2)-m), urea, and creatinine PD Cl. S-leptin was significantly elevated (Kruskal-Wallis, P < 0.005) in CAPD women (58.4 +/- 42.4 [SE] microg/L, n = 5) as compared with CAPD men (13.9 +/- 7.1, n = 10) and with healthy women (11.0 +/- 1.4, n = 13) and men (5.1 +/- 0. 9, n = 14). Correlations were found between percent of fat mass and S-leptin (P < 0.05); between S-leptin and the 24-hour PD leptin (P < 0.05); and between dialysate-to-plasma (D/P) beta(2)-m and D/P leptin (P < 0.01). PD leptin Cl (1.80 +/- 0.43 mL/min/1.73 m(2)) was higher than beta(2)-m Cl (1.22 +/- 0.31) (P < 0.01), but reduced as compared with urea Cl (8.84 +/- 1.20) (P < 0.005) and creatinine Cl (7.71 +/- 0.99) (P < 0.005). These results indicate that leptin is eliminated through the peritoneum membrane. However, peritoneal leptin clearance, as beta(2)-m, appears to be clearly restricted as compared with peritoneal transport of smaller molecules. Hence, leptin could use the same diffusion transport pathway as beta(2)-m. In addition, leptin, which has a higher molecular weight than beta(2)-m, was significantly more eliminated into the peritoneal dialysate. More studies are necessary to clarify whether this is an active leptin elimination process by peritoneal secretion or by a different restriction coefficient of diffusion through the peritoneum membrane.

Theoretical study of deprotonated glucopyranosyl disaccharide fragmentation.

Molecular orbital calculations were used to investigate the fragmentation of deprotonated glucopyranosyl disaccharides. Based on data from collisional activation and isotopic labeling experiments, fragmentation mechanisms are proposed, with calculated transition states being used to study the energetics of fragmentation. The calculations suggest that deprotonation at the C(2) hydroxyl of the non-reducing ring, following ring opening, may be important for disaccharide fragmentation. It is also shown that the stereochemistry at the 2-position of the non-reducing ring may have a significant effect on disaccharide fragmentation, particularly with regard to determination of the anomeric configuration.

[Secondary ulcer perforation after endoscopic hemostasis with fibrin glue]. / Die sekundäre Ulcusperforation nach endoskopischer Blutstillung durch Fibrinklebung.

Emergency treatment of bleeding ulcer of the duodenum is endoscopy and endoscopic blood-staunching. In high-risk patients with Forrest Ia lesions or ulcers with visible vessel (Forrest IIa) endoscopic follow-up or early elective operation is required. Fibrin sealing can improve the results of endoscopic injection therapy for bleeding ulcer. Nevertheless, severe complications such as secondary perforation of the fibrin clot or recurrent bleeding can occur. Identification of high-risk patients and complications requires close monitoring and attention. A case of a secondary perforation of a bleeding ulcer of the duodenum after fibrin sealing is reported.

Daily versus standard hemodialysis: one year experience.

The aim of this study was to compare clinical and biological results in 4 standard hemodialyzed patients originally treated by three 4-5 h sessions per week and converted within one year to daily hemodialysis sessions of 2-2.5 h each 6 times per week. The modalities and the total weekly dialysis times remained the same. With daily hemodialysis, the blood pressure and left ventricular mass index decreased significantly (p < 0.01). A significant decrease in the urea time averaged deviation (TAD) (p < 0.005) and increase in the Kt/V index (p < 0.05) were observed. A gain in dry weight was shown with a rise in caloric intake from 33+/-3.21 to 40.8+/-6.35 kcal/kg/day (p < 0.05), and the normalized protein catabolic rate (nPCR) increased significantly (p < 0.0038). One patient who was receiving erythropoietin (EPO) for anemia could stop his treatment. No arteriovenous fistula complications were observed. Daily hemodialysis seems to be the method of choice to manage hypertension and left ventricular hypertrophy in uremic patients. The increase of the urea TAD to a value closer to that of the healthy kidney due to the increase of the frequency of dialysis is probably the main explanation for clinical improvement.

Total body water and body composition in chronic peritoneal dialysis patients.

In this investigation, total body water (TBW) in ten chronic peritoneal dialysis patients was studied by deuterium (TBW-2H), skinfold thickness (TBW-ST), Watson formula (TBW-WA), 58% of body weight (TBW-58%), and bioelectrical impedance (TBW-BIA), and these results were compared with the reference oxygen18 (TBW-18O) method. We also analyzed the fat-free mass (FFM) by skinfold thickness (FFM-ST), bioelectrical impedance (FFM-BIA), oxygen18 (FFM-18O), and creatinine kinetics method (FFM-CK). In addition, resting metabolic rate was measured by indirect calorimetry. Compared with TBW-18O, TBW-58% and TBW-BIA were significantly different (P < 0.01). TBW-2H overestimated TBW-18O by 4.3%. TBW-ST and TBW-WA gave slightly greater values than TBW-18O, although these values were nonstatistically significant. The best prediction of total body water from these methods was obtained with the Watson formula. When Kt/V was calculated from these results, the values obtained were statistically greater (BIA, P < 0.001) and smaller (58% BW, P < 0.01) than those obtained with either 18O or Watson formula. The fat-free mass estimation also led to discrepant findings. Indeed, FFM-CK was significantly lower (P < 0.05) as compared with FFM-ST, FFM-BIA, or FFM-18O. Resting metabolic rate was strongly correlated with FFM estimated by skinfold thickness (r = 0.91, P < 0.001), bioelectrical impedance (r = 0.85, P < 0.005), and 18O (r = 0.77, P < 0.01), but not when fat-free mass was estimated by the creatinine kinetic method. The water content of fat-free mass estimated by skinfold thickness was found to be 69.7 +/- 6.9% in these patients, a value lower than the standard 73.2% found in healthy adults. This study confirms that there is an abnormal water distribution in chronic peritoneal dialysis patients. However, when compared with the oxygen18 reference method, the Watson formula allows a reliable estimation of Kt/V.

A photoionization study of the ion-neutral complexes CH3CH (+)CH 3 (·) CH 2CH 3] and CH 3CH 2CH (+)CH 3 (·) CH 3 in the gas phase: Formation, H-transfer and C-C bond formation between partners, and channeling of energy into dissociation.

Photoionization mass spectrometry was used to investigate the dynamics of ion-neutral complex-mediated dissociations of the n-pentane ion (1). Reinterpretation of previous data demonstrates that a fraction of ions 1 isomerizes to the 2-methylbutane ion (2) through the complex CH3CH(+)CH 3 (·) CH2CH3 (3), but not through CH3CH(+)CH2CH 3 (·) CH3 (4). The appearance energy for C3Hin 7 (+) formation from 1 is 66 kJ mol(-1) below that expected for the formation of n-C3H 7 (+) and just above that expected for formation of i-C3H 7 (+) . This demonstrates that the H shift that isomerizes C3H 7 (+) is synchronized with bond cleavage at the threshold for dissociation to that product. It is suggested that ions that contain n-alkyl chains generally dissociate directly to more stable rearranged carbenium ions. Ethane elimination from 3 is estimated to be about seven times more frequent than is C-C bond formation between the partners in that complex to form 2, which demonstrates a substantial preference in 3 for H abstraction over C-C bond formation. In 1 → CH3CH(+)CH2CH3 + CH3 by direct cleavage of the C1-C2 bond, the fragments part rapidly enough to prevent any reaction between them. However, 1 → 2 → 4 → C4H 8 (+) + CH4 occurs in this same energy range. Thus some of the potential energy made available by the isomerization of n-C4H9 in 1 is specifically channeled into the coordinate for dissociation. In contrast, analogous formation of 3 by 1 → 3 is predominantly followed by reaction between the electrostatically bound partners.

Characterization of a truncated form of recombinant porcine growth hormone generated in vitro during solubilization of inclusion bodies.

During the development of a novel solubilization procedure (1) for bacterial inclusion bodies (IB's) using the cationic surfactant cetyltrimethylammonium chloride (CTAC; (CH3)3-N(+)-C16H33Cl) significant proportions of an apparently truncated, lower molecular weight (MW) variant form of recombinant pig growth hormone (rPGH) were observed on sodium dodecyl sulfate-polyacrylamide gel electrophoresis relative to pig pituitary derived GH. The formation of this rPGH-like species, designated P-band, was found to occur in vitro during solubilization of IB's by CTAC and was dependent on pH and temperature of solubilization, but was not due directly to the use of CTAC, as purified soluble rPGH of the correct MW could not be converted to P-band by exposure to CTAC alone. The bacterial proteolysis suspected as being responsible for the in vitro formation of P-band could not be inhibited by the use of a "cocktail" of defined antiproteolytic agents but was inhibited by pH and temperature, and by solubilization of IB's in 5% SDS, 6 M gnHCl or 7.5 M urea. Detailed characterization of the structure of P-band by N-terminal amino acid sequencing, electrospray mass spectrometry, radioreceptor binding assay, peptide mapping, and C-terminal peptide sequencing confirmed that P-band was approximately 950 mass units smaller than normal rPGH and lacked eight C-terminal amino acids. A significant finding was that P-band is unable to bind to the pig liver-membrane GH receptor in a competitive radioreceptor assay. Analysis of the relative secondary and tertiary structure of P-band by circular dichroism spectra, intrinsic tryptophan-dependent fluorescence, and average surface hydrophobicity (2) suggested small but measurable changes to the overall structure of P-band relative to normal rPGH. Consequently, our results also suggest that the C-terminal portion of rPGH, including in particular the last eight amino acids, is of major importance in the binding of rPGH to the pig liver membrane GH receptor.

Quantification of adequacy of peritoneal dialysis.

Nineteen patients treated by continuous ambulatory peritoneal dialysis (CAPD) were studied according to clinical outcome parameters: insomnia, asthenia, pruritus, arterial hypertension, anorexia, nausea and/or vomiting, anemia, and rate of hospitalization. Using clinical scores, three groups were defined: poor clinical outcome (P), intermediate (I), and good (G). The quantity of treatment by PD was evaluated monthly with urea kinetic tests (weekly Kt/V, weekly urea clearance/1.73 m2 of body surface area (BSA), index of dialysis by Teehan), and with the weekly creatinine clearance/1.73 m2 of BSA. The metabolic index was analyzed: normalized protein catabolic rate (NPCR), serum albumin (Alb) and prealbumin, and reabsorption of glucose. There was good correlation between clinical scores and quantity of dialysis. The Alb was lower in group P. Group G was differentiated from group I and from group P by quantification tests and NPCR, with lower levels as follows: weekly Kt/V = 2.06, urea clearance 70 L/week/1.73 m2, index of dialysis = 0.87, and creatinine clearance = 60 L/week/1.73 m2. We conclude that the qualitative clinical approach is not sufficient to predict deleterious signs, and the quantitative approach is predictive of the good clinical outcome and good nutritional status. We think that levels proposed to now are insufficient, and we suggest the following: weekly urea clearance > 70 L, weekly Kt/V > 2, weekly creatinine clearance > 60 L, and index of dialysis > 0.85.

Identification of glutamic acid 105 at the active site of Bacillus amyloliquefaciens 1,3-1,4-beta-D-glucan 4-glucanohydrolase using epoxide-based inhibitors.

Bacillus amyloliquefaciens 1,3-1,4-beta-D-glucan 4-glucanohydrolase (EC 3.2.1.73) was modified by the mechanism-based, affinity-labeling reagent [14C](3,4)-epoxybutyl beta-D-cellobioside. Following partial inactivation a completely inactivated enzyme preparation containing 1.1 mol of covalently bound inhibitor/mol of protein was obtained by chromatography on a cellulosic matrix. The inactivated enzyme was digested with endoproteinase Glu-C and radioactive peptides purified by reversed-phase high performance liquid chromatography (HPLC). The affinity label was esterified exclusively to the gamma-carboxylate of Glu105 in the sequence Gly-Thr-Pro-Trp-Asp-Glu-Ile-Asp-Ile-Glu109. The sequence motif Glu-(Ile/Leu)-Asp-Ile is found in many glucanases and xylanases and may therefore serve to identify the catalytic nucleophile in beta-glycanases, which otherwise exhibit a low degree of sequence identity. The esterification of Glu105 by the affinity label abolished endoproteinase Glu-C-mediated hydrolysis of the Glu-Ile106 peptide bond. Identification of phenylthiohydantoin-Glu105 during automated sequence analysis was not possible unless the affinity label was liberated by prior base hydrolysis. These observations formed the basis for the development of a highly sensitive approach for the identification of catalytic carboxylates in polysaccharide hydrolases employing non-radioactive inhibitors, comparative HPLC mapping, electrospray mass spectrometry, and Edman degradation.

A new device for specific extracorporeal immunoadsorption of anti-DNA antibodies. In vitro and in vivo results.

Selective removal of anti-DNA antibodies could be an alternative to therapeutic plasma exchange in patients with active systemic lupus erythematosus. The method is based on the immobilization by covalent binding of double-stranded, calibrated, 0.3-kb DNA fragments on a microporous, methylated, polyacrylonitrile membrane. This enables linkage of 60 micrograms of DNA per cm2 of apparent surface area. In vitro, perfusion of 100 ml of plasma maintained at 37 degrees C through 650 cm2 of dsDNA linked to the membrane, at a flow rate of 1.5 ml/min for 60 min, resulted in the removal of 49-89% of anti-DNA IgG without any changes in plasma protein or IgG levels. During a therapeutic plasma exchange, perfusion of the plasma through 1.5 m2 of membrane, at a flow rate of 25 ml/min, initially removed 92% of the anti-dsDNA antibodies entering the adsorbent and 25% at 120 min, indicating a progressive saturation of the binding capacity. Clinical immunoadsorption, at a plasma flow rate of 20-40 ml/min through 2 m2 of membrane, removed more than 50% of anti-dsDNA IgG within 60 min. Microporous membranes are able to irreversibly bind large amounts of antigenic ligands, and enable the selective removal of pathogenetic immunoglobulins or circulating factors.

Formation of the 3-Pentanone ion from ionized propyl propanoate through Ion-Neutral complexes.

Formation of the 3-pentanone ion (3) from ionized propyl propanoate through the complex [C2H5CO(+) (•)OC3H7] is proposed based on data obtained by photoionization. The threshold and energy dependence for forming 3 relative to those for related processes support this proposal. The threshold for forming 3 coincides with that predicted for forming [CH3CH2CO(+) (•)CH2CH3], suggesting that that complex is also an intermediate in the pathway to 3. 3-Pentanone ion formation is important much further above threshold than is alkane elimination through [RCO(+) (•)R] complexes. This adds to evidence that reactions between the partners in ion-dipole complexes take place over a wider energy range than do such reactions in complexes containing nonpolar neutral partners.

Isomeric ion-neutral complexes generated from ionized 2-Methylpropanol and n-Butanol: the effect of the polarity of the neutral partner on complex-mediated reactions.

Photoionization was used to characterize the energy dependence of C3H 7 (+) , C3H 6 (+) , CH3OH 2 (+) and CH2=OH(+) formation from (CH3)2)CHCH2OH(+•) (1) and CH3CH2CH2CH2OH(+•) (2). Decomposition patterns of labeled ions demonstrate that close to threshold these products are primarily formed through [CH 3 (+) CHCH3 (•)CH2OH] (bd3) from 1 and through [CH3CH2CH2 (•)CH2=OH(+)] (9) from 2. The onset energies for forming the above products from 1 are spread over 85 kJ mol(-1), and are all near thermochemical threshold. The corresponding onsets from 2 are in a 19 kJ mol(-1) range, and all except that of CH2=OH(+) are well above their thermochemical thresholds. Each decomposition of 3 occurs over a broad energy range (> 214 kJ mol(-1)), This demonstrates that ion-permanent dipole complexes can be significant intermediates over a much wider energy range than ion-induced dipole complexes can be. H-exchange between partners in the complexes appears to be much faster than exchange by conventional interconversions of the alcohol molecular ions with their distonic isomers. The onsets for water elimination from 1 and 2 are below the onsets for the complex-mediated processes, demonstrating that the latter are not necessarily the lowest energy decompositions of a given ion when the neutral partner in the complex is polar.