Search

Chronic kidney disease (CKD) affects over 10% of the global population. One crucial complication of CKD is secondary hyperparathyroidism (SHPT), marked by elevated parathyroid hormone levels due to hyperphosphataemia, hypocalcaemia, and low active vitamin D from impaired renal function. SHPT increases risks of bone deformities, vascular calcification, cardiovascular events and mortality. This review examines SHPT treatment strategies in patients with CKD. First-line treatments include phosphate binders, vitamin D receptor activators and calcimimetics. When these fail, invasive options like parathyroidectomy (PTX) and thermal ablation are considered. PTX effectively reduces symptoms and improves radiological outcomes, outperforming medical treatment alone in reducing cardiovascular risk and mortality. Thermal ablation techniques, such as microwave, radiofrequency, laser or high-intensity focused ultrasound, offer less invasive alternatives with promising results. Future research should explore the molecular mechanisms of parathyroid gland hyperplasia and evaluate various treatments' impacts., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Autonomic nervous system (ANS) dysfunction is prevalent in end-stage kidney disease (ESKD) patients, carrying significant risks for morbidity and mortality. Heart rate variability (HRV) is a simple and non-invasive method to evaluate ANS functions and predict prognoses in specific patient populations. Since there is a lack of a clear understanding of the clinical significance of HRV in predicting prognoses in ESKD patients, an updated review on this topic is urgently warranted. The clinical significance of HRV in dialysis patients includes its associations with metabolic syndrome, nutritional status, intradialytic hypotension, vascular access failure, major adverse cardiovascular events, and mortality. These findings underscore the essential role of the autonomic reserve, which might denote the elevation of ANS activity as a response to external stimulus. Patients with a higher level of sympathetic activity at the resting stage, but who are unable to adequately elevate their sympathetic activity under stress might be susceptible to a worse outcome in critical circumstances. Further applications of HRV include HRV biofeedback, risk classification, and real-time HRV monitoring. Overall, HRV is an optimal tool for predicting prognoses in dialysis patients. Further study is encouraged in order to gain a clearer understanding of the clinical significance and application of HRV, and thereby enhance the care of ESKD patients.

The cell walls of the genus Rhodococcus including the pathogenic bacterium Rhodococcus equi ( R. equi ) and biotechnologically important bacterium Rhodococcus opacus ( R. opacus ) contain an abundant p eptidolipid (or termed lipopeptide) family whose structures have not been reported previously. Here, we describe a linear ion-trap multiple-stage mass spectrometric (LIT MS n ) approach with high resolution mass spectrometry (HRMS), in conjunction with NMR spectroscopy, chemical reactions, and GC/MS analysis to define the structures of these compounds. We employed LIT MS n ( n = 2-8) on the [M + Na] + ion species to establish the peptide sequence, the identity of the fatty acyl substituent, and its location within the molecule, while NMR spectroscopy and GC/MS were used to recognize the Leu and Ile moieties. The major new lipopeptide found in R. opacus is defined as C 17 H 35 CH(OH)CH 2 CO-NHLeu-Ser-Leu-Ile-Thr-Ile-PheCOOH, where a β-OH fatty acyl (C 18 -C 22 ) substituent is attached to the N-terminal of the LSLITIF peptide chain via a NH-CO bond. By contrast, the main peptidolipids found in R. equi belong to the cyclopeptidolipid family, which possesses the same peptide sequence and lipid chain, but the β-OH group of the fatty acyl moiety and the C-terminus of the peptide (i.e., the -COOH) are cyclized by an ester bond formation to a lactone, with a structure similar to iturin-A (Peypoux, F. et al. Biochemistry 1978, 17, 3992-3996). The antibiotic activity test of these new lipids did not reveal an activity against any of seven microorganisms tested.

The repeated measurements of heart rate variability (HRV) is more relevant than a single HRV measurement in predicting patient prognosis but is less addressed previously. This prospective study aimed to investigate the association between repeated measurements of HRV and long-term mortality in chronic hemodialysis patients. The 164 patients (65.0 ± 13.1 years; woman, 57.3%) were enrolled from June 1, 2010, to August 31, 2010, and received four HRV measurements (before and during the index hemodialysis session) after the enrollment. The baseline characteristic and clinical variables, including mortality, were documented. The joint modeling method and Cox regression were used for statistical analyses. After an 8-year follow-up, 79 patients expired, and 85 patients survived. We found that higher normalized high-frequency (nHF) (hazard ratio [HR] 1.033) as well as lower very-low-frequency (HR 0.990), Variance (HR 0.991), normalized low-frequency (HR 0.999, P = 0.006), and low-frequency/high-frequency ratio (HR 0.796) were independent predictors for cardiovascular mortality. Whereas the independent predictors for infection-associated mortality included higher nHF (HR 1.033) as well as higher age (HR 19.29) and lower serum albumin (HR 0.01, P = 0.001). (all P < 0.001 unless otherwise stated) In conclusion, HRV measurement predicts long-term mortality among hemodialysis patients.

Background: Phosphate binders have an impact on fibroblast growth factor 23 (FGF23); however, the effect of phosphate binders on serum hepcidin has not been explored. We conducted a 24-week multicenter randomized controlled trial to investigate the effects of lanthanum carbonate or calcium carbonate monotherapy on serum phosphate, FGF23, and hepcidin levels in chronic hemodialysis patients., Methods: Forty-six patients were recruited, and daily dietary phosphorus was controlled between 600-800 mg. Serum calcium, phosphate, albumin, alkaline phosphatase (ALP), FGF23, intact parathyroid hormone (iPTH), hepcidin, high-sensitivity CRP (hsCRP), 25(OH)D, 1,25(OH) 2 D, fetuin-A, and osteopontin were checked as scheduled., Results: Twenty-five patients completed the study. Mean serum FGF23 level was significantly decreased after a 24-week treatment with lanthanum (8677.5 ± 7490.0 vs. 4692.8 ± 5348.3 pg/mL, p = 0.013, n = 13), but not with calcium (n = 12). The reduction of serum hepcidin in lanthanum group was positively correlated with the decrement of serum phosphate (r = 0.631, p = 0.021) and serum hsCRP (r = 0.670, p = 0.012) levels, respectively. Serum ALP, iPTH, vitamin D, fetuin-A, and osteopontin revealed no significant inter- or intragroup differences., Conclusions: In summary, a decrease in serum FGF23 levels and a trend of decline in hepcidin levels were observed only in lanthanum group.

Background: Vascular access (VA) is the lifeline of hemodialysis patients. Although the autonomic nervous system might be associated with VA failure (VAF), it has never been addressed in previous studies. This study aimed to evaluate the predictive values of the heart rate variability (HRV) indices for long-term VA outcomes., Methods: This retrospective study was conducted using a prospectively established cohort enrolling 175 adult chronic hemodialysis patients (100 women, mean age 65.1 ± 12.9 years) from June 2010 to August 2010. Each participant received a series of HRV measurements at enrollment. After a 60-month follow-up period, we retrospectively reviewed all events and therapeutic procedures of the VAs which existed at the enrollment and during the follow-up period., Results: During the 60-month follow-up period, 37 (26.8%) had VAF but 138 (73.2%) didn't. The values of most HRV indices were statistically increased during hemodialysis since initiation in the non-VAF group, but not in the VAF group. Among all participants, the independent indicators for VAF included higher normalized high-frequency (nHF) activity [hazard ratio (HR) 1.04, p = 0.005], lower low-frequency/high-frequency (LF/HF) ratio (HR 0.80, p = 0.015), experience of urokinase therapy (HR 11.18, p = 0.002), percutaneous transluminal angioplasty (HR 2.88, p = 0.003) and surgical thrombectomy (HR 2.36, p = 0.035), as well as higher baseline serum creatinine (HR 1.07, p = 0.027) and potassium level (HR 1.58, p = 0.037). In subgroup analysis, a lower sympathetic activity indicated by lower LF/HF ratio was an independent indicator for VAF (HR 0.61, p = 0.03) for tunneled cuffed catheter, but conversely played a protective role against VAF (HR 1.27, p = 0.002) for arteriovenous fistula., Conclusions: HRV is a useful tool for predicting long-term VAF among hemodialysis patients.

Background: Intradialytic hypotension (IDH) carries adverse impact. Heart rate variability (HRV) represents autonomic cardiac regulation which influences intradialytic blood pressure. We aimed to evaluate the association between IDH and HRV., Methods: This prospective study was carried out in a teaching hospital in Taiwan from June to August 2010. Adult patients on chronic hemodialysis without active medical conditions were enrolled and received HRV measurements for 4 times (before and during an index hemodialysis session). Patients were categorized by the changes of systolic blood pressure during the index hemodialysis into Group 1 (elevation >20 mmHg), Group 2 (decrease >20 mmHg), and Group 3 (others). Then we compared HRV indices among the three groups, and determined the indicators for IDH., Results: One hundred and seventy-one patients (96 women, mean age 64.9 years) were enrolled and categorized into Group 1 (n = 47, 27.5 %), Group 2 (n = 45, 26.3 %) and Group 3 (n = 79, 46.2 %). Comparing with Group 1 and/or Group 3, Group 2 had significantly higher blood pressure at hemodialysis initiation (most p < 0.001) and statistically lower levels of HRV indices including variance, total power, very low-frequency, low-frequency and high-frequency since the middle phase of the hemodialysis. By logistic regression method, higher systemic blood pressure [odds ratio (OR) 1.048; p < 0.001], heart rate (OR 1.093; p = 0.021), low-frequency/high-frequency ratio (OR 1.715; p = 0.022), as well as lower variance (OR 0.639; p = 0.048) at hemodialysis initiation were independently associated with intradialytic blood pressure changes., Conclusions: HRV is a useful indicator for IDH among hemodialysis patients.

Background: Both uremia and metabolic syndrome (MetS) affect heart rate variability (HRV) which is a risk factor of poor prognoses. The aim of this study was to evaluate the impact of MetS on HRV among chronic hemodialysis patients., Methods: This cross-sectional study was carried out in a teaching hospital in Northern Taiwan from June to August, 2010. Adult patients on chronic hemodialysis without active medical conditions were enrolled. HRV were measured for 4 times on the index hemodialysis day (HRV-0, -1, -2, and -3 at before, initial, middle, and late phases of hemodialysis, respectively), and the baseline demographic data and clinical parameters during the hemodialysis session were documented. Then we evaluated the impacts of MetS and its five components on HRV., Results: One hundred and seventy-five patients (100 women, mean age 65.1 ± 12.9 years) were enrolled and included those with MetS (n = 91, 52 %) and without MetS (n = 84, 48 %). The patients with MetS(+) had significantly lower very low frequency, total power, and variance in HRV-0, total power and variance in HRV-2, and variance in HRV-3. (all p ≦ 0.05) When using the individual components of MetS to evaluate the impacts on HRV indices, the fasting plasma glucose (FPG) criterion significantly affected most indices of HRV while other four components including "waist circumference", "triglycerides", "blood pressure", and "high-density lipoprotein" criteria exhibited little impacts on HRV. FPG criterion carried the most powerful influence on cardiac ANS, which was even higher than that of MetS. The HRV of patients with FPG(+) increased initially during the hemodialysis, but turned to decrease dramatically at the late phase of hemodialysis., Conclusions: The impact of FPG(+) outstood the influence of uremic autonomic dysfunction, and FPG criterion was the most important one among all the components of MetS to influence HRV. These results underscored the importance of interpretation and management for abnormal glucose metabolism.

The authors report a 74-year-old man with chronic hepatitis C-related cirrhosis and end-stage renal disease undergoing maintenance haemodialysis who was diagnosed with hepatoma. The hepatoma spontaneously regressed with significantly decreased serum alpha-fetoprotein level without any treatment during the subsequent 4-year follow-up period. However, recurrent hepatomas over bilateral hepatic lobes were evident thereafter, and the patient died later due to hepatic failure. Hepatoma with ring calcification is extremely rare and considered poor differentiation with high risk for recurrence. Spontaneous regression of hepatoma is also rare, while spontaneous regression occurring in a hepatoma with ring calcification is never reported. The definite mechanisms causing spontaneous regression of hepatomas remain unclear, but an immune response toward hepatoma induced by alpha-fetoprotein might play an important role.

A novel analogue of sibutramine, 11-desisobutyl-11-benzylsibutramine, has been discovered. During routine ion mobility spectrometry (IMS) screening of a weight loss supplement collected at an US FDA import operation facility an unknown peak was observed. Further analysis of the supplement by liquid chromatography-mass spectrometry (LC-MS) and high resolution mass spectrometry revealed an unknown peak with a relative retention time of 1.04 with respect to sibutramine and a predicted formula of C20H24NCl. In order to elucidate the analogue's structure, it was isolated from the supplement and characterized by tandem mass spectrometry and nuclear magnetic resonance (NMR), which revealed the analogue possessed a benzyl moiety at the 11 position in place of the isobutyl group associated with sibutramine., (Copyright © 2013. Published by Elsevier B.V.)

Nucleoside analogues, such as penciclovir, ganciclovir, acyclovir, and their fluoro-substituted derivatives, have wide utility as antivirals. Among these analogues, FHBG ((18)F-Fluorohydroxybutylguanine) is a well-validated PET (positron emission tomography) probe for monitoring reporter gene expression. To evaluate whether or not imposing rigidity into the flexible side chain of FHBG 4 could also impact its interaction, with amino acid residues within the binding site of HSV1-TK (Herpes Simplex Virus-1 Thymidine Kinase), thus influencing its cytotoxic activity. Herein, the synthesis of a new fluorinated nucleoside analogue 6 (conceived via ligand-docking studies) is reported. Agent 6 demonstrates selective activity against HeLa cells stably transfected with mutant HSV1-sr39TK and is also 47-fold more potent than FHBG.

Case Study: Mr Lin, a Chinese man aged 38 years, presented for review of a recent chest X-ray. The X-ray was ordered as part of a pre-employment assessment. He was asymptomatic, a nonsmoker and had no significant past medical history. Full blood examination, lipids, glucose and liver and renal function were normal (also ordered as part of the pre-employment assessment). On examination, he looked well, with blood pressure 134/78 mmHg, heart rate 72/min, and chest and cardiovascular examinations normal.

The mature pro forms of the cardiac natriuretic peptides, atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), are proteolytically processed to their active hormone forms (28 and 32 residues, respectively) and N-terminal (NT)-pro fragments (68 and 76 residues, respectively). Far-ultraviolet circular dichroism (UV CD), 1D and 2D-homonuclear nuclear magnetic resonance (NMR), size exclusion-high performance liquid chromatography (SE-HPLC) and analytical ultracentrifuge sedimentation equilibrium (AUCSE) data are obtained for NT-proANP. CD data showed a large negative molar ellipticity for NT-proANP of -14,800° cm(2)/dmol at 199-200 nm. The intensity of the 1D-(1)H NMR spectra in the amide region for NT-proANP was very low and confined to ~8-8.6 ppm. Furthermore, cross-correlation resonance peaks were absent in the corresponding 2D-(1)H NOE spectra for NT-proANP in this region. The elution peak for this fragment from a G2000SW size-exclusion column was 20.4'; myoglobin (~17 K) was also eluted at 20.4'. No higher molecular weight oligomers were evident in the AUCSE experiments for NT-proANP. Collectively, the physical data demonstrate that NT-proANP, like NT-proBNP, is primarily a disordered, monomeric protein. Lastly, we compare the predictions from two in silico metaserver disorder algorithms, MeDor and MetaPrDOS, to the experimental data.

We compared perinatal outcomes in pregnancies in which insulin glargine was used in the management of patients with pregnancies in which standard insulin therapy was used at a single institution. A retrospective analysis of 114 pregnant patients with diabetes (pregestational or gestational) managed at a single center between January 2004 and August 2006 was undertaken. Sixty-five patients managed with insulin glargine were compared with 49 patients managed with neutral protamine Hagedorn (NPH) insulin. Both groups were also treated with short-acting insulin (either regular, lispro, or aspart insulin). Maternal age, parity, prepregnancy weight, body mass index, duration of diabetes, hemoglobin A (1C) (at entry and final recorded) and gestational age at entry were similar for each group (glargine and NPH). Thirty patients had gestational diabetes (18 glargine and 12 NPH); there were no differences in numbers of patients in higher-order White's classification between the two groups. Cesarean section for obstetric reasons included labor abnormalities, malpresentation, fetal distress, and suspected macrosomia. There were no differences in gestational age at delivery, birth weight, preeclampsia, or frequency of cesarean section (total or for obstetric reasons). The frequency of shoulder dystocia was higher in the NPH group. Regarding neonatal outcomes, gestational age at delivery, birth weight, Apgar scores, admission to the neonatal intensive care unit, respiratory distress syndrome, hypoglycemia, and congenital anomalies were similar between the two groups. From this retrospective analysis, no adverse maternal or neonatal effects were seen from maternal administration of insulin glargine. A larger multicenter study is needed to confirm these findings. This preliminary report suggests that use of insulin glargine during pregnancy can be considered if maternal metabolic control is suboptimal using the standard split-mix regimen., (Thieme Medical Publishers.)

Inhibitors of heat-induced heat shock protein 70 (HSP70) expression have the potential to enhance the therapeutic effectiveness of heat-induced radiosensitization of tumors. Among known small molecule inhibitors, quercetin has the advantage of being easily modified for structure-activity studies. Herein, we report the ability of five monomethyl and five carbomethoxymethyl derivatives of quercetin to inhibit heat-induced HSP70 expression and enhance HSP27 phosphorylation in human cells. While quercetin and several derivatives inhibit HSP70 induction and enhance HSP27 phosphorylation at Ser78, other analogues selectively inhibit HSP70 induction without enhancing HSP27 phosphorylation that would otherwise aid in cell survival. We also show that good inhibitors of HSP70 induction are also good inhibitors of both CK2 and CamKII, kinases that are known to activate HSP70 expression by phosphorylation of heat shock transcription factor 1. Derivatives that show poor inhibition of either or both kinases are not good inhibitors of HSP70 induction, suggesting that quercetin's effectiveness is due to its ability to inhibit both kinases.

Tri-n-octylphosphine oxide (TOPO) is the most commonly used solvent for the synthesis of colloidal nanocrystals. Here we show that the use of different batches of commercially obtained TOPO solvent introduces significant variability into the outcomes of CdSe quantum-wire syntheses. This irreproducibility is attributed to varying amounts of phosphorus-containing impurities in the different TOPO batches. We employ (31)P NMR to identify 10 of the common TOPO impurities. Their beneficial, harmful, or negligible effects on quantum-wire growth are determined. The impurity di-n-octylphosphinic acid (DOPA) is found to be the important beneficial TOPO impurity for the reproducible growth of high-quality CdSe quantum wires. DOPA is shown to beneficially modify precursor reactivity through ligand substitution. The other significant TOPO impurities are ranked according to their abilities to similarly influence precursor reactivity. The results are likely of general relevance to most nanocrystal syntheses conducted in TOPO.

UVB irradiation of DNA produces photodimers in adjacent DNA bases and on rare occasions in nonadjacent bases. UVB irradiation (312 nm) of d(GTATCATGAGGTGC) gave rise to an unknown DNA photoproduct in approximately 40% yield at acidic pH of about 5. This product has a much shorter retention time in reverse phase HPLC compared to known dipyrimidine photoproducts of this sequence. A large upfield shift of two thymine H6 NMR signals and photoreversion to the parent ODN upon irradiation with 254 nm light indicates that the photoproduct is a cyclobutane thymine dimer. Exonuclease-coupled MS assay establishes that the photodimer forms between T2 and T7, which was confirmed by tandem mass spectrometric MS/MS identification of the endonuclease P1 digestion product pd(T2[A3])=pd(T7[G8]). Acidic hydrolysis of the photoproduct gave a product with the same retention time on reverse phase HPLC and the same MS/MS fragmentation pattern as authentic Thy[ c,a]Thy. 2D NOE NMR data are consistent with a cis-anti cyclobutane dimer between the 3'-sides of T2 and T7 in anti glycosyl conformations that had to have arisen from an interstand type reaction. In addition to pH dependency, the photoproduct yield is highly sequence specific and concentration dependent, indicating that it results from a higher order folded structure. The efficient formation of this interstrand-type photoproduct suggests the existence of a new type of folding motif and the possibility that this type of photoproduct might also form in other folded structures, such as G-quadruplexes and i-motif structures which can be now studied by the methods described.

The N-terminal fragment of pro B-type natriuretic peptide (NT-proBNP) and proBNP are used as gold standard clinical markers of myocardial dysfunction such as cardiac hypertrophy and left ventricle heart failure. The actual circulating molecular forms of these peptides have been the subject of intense investigation particularly since these analytes are measured in clinical assays. Conflicting data has been reported and no firm consensus on the exact nature of the molecular species exists. Because these clinical assays are immunoassay-based, specific epitopes are detected. It is conceivable then that certain epitopes may be masked and therefore unavailable for antibody binding, thus the importance of determining the nature of the circulating molecular forms of these analytes. This situation is an unavoidable Achilles' heel of immunoassays in general. A recombinant O-linked glycosylated form of proBNP has been show to mimic some of the properties of extracted plasma from a heart failure patient. In particular the recombinant and native material co-migrated as diffuse Western-immunostained bands on SDS-PAGE and each band collapsed to an apparent homogeneous band following deglycosylation. Thus, glycosylated-proBNP may be one such circulating form. Here we provide extensive physiochemical characterization for this O-linked protein and compare these results to other described circulating species, non-glycosylated-proBNP and NT-proBNP. It will be shown that glycosylation has no influence on the secondary and quaternary structure of proBNP. In fact, at moderate concentration in benign physiological neutral pH buffer, all three likely circulating species are essentially devoid of major secondary structure, i.e., are intrinsically unstructured proteins (IUPs). Furthermore, all three proteins exist as monomers in solution. These results may have important implications in the design of NT-proBNP/BNP immunoassays.

Phosphinic compounds have potential as amide-bond mimetics in the development of novel peptidomimetics, enzyme inhibitors, and metal-binding ligands. Novel pseudo-oligopeptides with two phosphinic acid groups embedded in the peptide backbone serving as amide-bond surrogates, Psi[P(O,OH)--CH(2)], were targeted. A series of linear and cyclic pseudo-oligopeptides with two phosphinic acid groups arrayed at different positions in the peptide sequence were designed, including Ac--Phe--{(R,S)--AlaPsi[P(O,OH)--CH(2)]Gly}(2)--NH(2) (P2), Ac--NH--(R,S)--AlaPsi[P(O,OH)--CH(2)]Gly--Phe--(R,S)--AlaPsi[P(O,OH)--CH(2)]Gly--NH(2) (P3), Ac--NH--(R,S)--AlaPsi[P(O,OH)--CH(2)]Gly--Phe--Phe--(R,S) --AlaPsi[P(O,OH)--CH(2)]Gly--NH(2) (P4), cyclo{NH--(R,S)--AlaPsi[P(O,OH)--CH(2)]Gly--Phe}(2) (P5), and cyclo[NH--(R,S)--AlaPsi[P(O,OH)--CH(2)]Gly--Phe--Phe](2) (P6). They were synthesized via conventional Fmoc chemistry on solid support utilizing Fmoc-protected phosphinic acid-containing pseudo-dipeptide fragment, i.e. Fmoc--(R,S)--AlaPsi[P(O,OCH(3))--CH(2)]Gly--OH. The pseudo-peptides containing two phosphinic acid groups exhibited the highest binding affinity and selectivity for Fe(III) among the 10-metal ions screened by ESI-MS analysis--Cu(II), Zn(II), Co(II), Ni(II), Mn(II), Fe(II), Fe(III), Al(III), Ga(III), and Gd(III). P4 and P6 with 11-atom linkages between the two phosphinic acids preferred intramolecular metal binding to form 1:1 ligand/metal complexes. As revealed by competition experiments, P4 showed the highest relative binding affinity among the six compounds tested. Noteworthy, P4 also showed higher relative binding affinity than similar dihydroxamate-containing pseudo-peptides reported previously. The novel structural prototype and facile synthesis along with selective and potent Fe(III) binding strongly suggest that pseudo-peptides containing the two or more phosphinic groups as amide-bond surrogates deserve further exploration in medicinal chemistry.

The cardiac hormone B-type natriuretic peptide (BNP) is synthesized as a prepro 134 residue molecule which is further proteolytically processed into a 76 residue fragment termed N-terminal proBNP (NT-proBNP) and the active portion of this hormone, a 32-residue disulfide-linked peptide (BNP-32). The active hormone regulates cardiac hemodynamic output while as yet no biological function has been attributed to NT-proBNP. Some solution properties of synthetically generated NT-proBNP in benign media are known. The protein is monomeric, elutes aberrantly on size-exclusion chromatography as an apparent larger molecular species, and possesses little global secondary structure as assessed by circular dichroism. To explore the solution structure of NT-proBNP in greater detail, we use 2D-NOESY and 2D-TOCSY NMR on recombinant NT-proBNP to obtain a high resolution solution conformation at the alpha-carbon level. Importantly, NH(i)-NH(i+1) coupling is virtually absent at room temperature implying that large stretches of primary sequence are unordered. Together, the results of these physicochemical measurements classify NT-proBNP as a naturally unfolded protein referred to as an Intrinsically Unstructured Protein (IUP). The calculations of FoldIndex, a computer program which predicts disorder, were compared to the experimental results described here for NT-proBNP in addition to proBNP. NT-proBNP thus appears to be an ideal candidate for the study of native, unfolded proteins.

Background/aims: Blunt pancreatic duct injury is difficult to differentiate, especially during surgery. In terms of demonstration of pancreatic duct injury, endoscopic retrograde pancreatography (ERP) is the gold standard imaging study, however, availability can be problematic. Therefore, we have designed a method utilizing lesser-sac lavage to differentiate pancreatic duct injury., Methodology: Patients sustaining blunt pancreatic trauma treated at our institution over a two-year period were retrospectively enrolled in this study. Based on computed tomography (CT), these patients were divided into two groups: deep laceration or complete transection (Group 1) and superficial laceration (Group 2). Additionally, ten patients sustaining blunt abdominal trauma who had undergone emergency laparotomy for other visceral organ injury (Group 3) and four undergoing pancreatoduodenectomy (Group 4) were selected as controls. For laparotomy in Groups 1-3, the lesser sac was opened for lavage, with 50 mL of 0.9% normal saline inserted, and 3mL of the sample fluid withdrawn at four time points (15, 30, 45 and 60 mins) with the fluid immediately replaced with 3 mL of saline. Lavage-ascites amylase (LAA) and lipase (LAL) levels were measured. Serum amylase and lipase activities were measured intraoperatively from 3mL of the patient's blood., Results: Over the two-year study period, there were four pancreatic duct transections (Group 1), five partial pancreatic lacerations confirmed by post-ERP CT (Group 2), ten non-pancreatic traumas (Group 3), and four pancreatoduodenectomies due to pancreatic-head cancer (Group 4). The LAA and LAL for Group 1 were significantly higher than those for Group 2 or 3 at each of the four time points. The LAA and LAL ratios for Group 1 relative to Group 2 or 3 decreased gradually over time. These LAA ratios ranged from 7-13 for Group 1 to Group 2, 138-232 for Group 1 to Group 3, and 17-21 for Group 2 to Group 3. By contrast, the LAL ratio ranged from 3.0-3.4 comparing Group 1 to Group 2, 3180-29124 for Group 1 to Group 3, and 1058-8705 for Group 2 to Group 3., Conclusions: Using lesser-sac lavage for measurement of LAA and LA L constitutes a rapid, non-invasive and effective method for detection of pancreatic duct injury, especially transection of the main duct. LAA appears to be a better indicator for differentiation of minor (superficial laceration or side branch) or major (MPD) pancreatic injury at the first time point (15 minutes post lavage) compared to LAL. By contrast, LAL appears to be a better indicator with respect to differentiation of the injured pancreas from the normal organ at this time point.

We have investigated rarely observed 77Se J-couplings (spin-spin couplings) in the mixed-metal face-capped octahedral clusters [Re5OsSe8(CN)6]3- and [Re4Os2Se8(CN)6]2- at natural abundance. To the best of our knowledge, these are the first observations of Se-Se spin-spin interactions between mu3-Se sites, important for stereochemical assignments in hexarhenium analogues, Chevrel phase materials, and similar cluster materials. NMR techniques such as COSY, INADEQUATE, and 2D J-resolved spectroscopy have been used in conjunction to study these interactions. The two isomers (cis and trans) of [Re4Os2Se8(CN)6]2- were distinguishable, and selective isotopic labeling of [Re5OsSe8(CN)6]3- with 13CN ligands enabled resonances to be assigned by observing the 2J (Se-M-C) couplings. For [Re5OsSe8(CN)6]3-, two different 2J (Se-M-Se) couplings were measurable on a single cluster, and these are related to one another through spin-spin interactions across a face diagonal or along an edge of the cube of inner selenium ligands. A rigorous analysis based on combinatorial math has been invoked to assign the couplings on the basis of the probability of multiple-spin interactions. The face diagonal association is found to result in a J-coupling interaction larger in magnitude than that from coupling along an edge of the cube-information critical for making stereochemical assignments of selenium sites.

Lysosphingolipids are important lipid signaling molecules that are associated predominantly with high density lipoproteins (HDL) in human plasma. Further, HDL has been shown to be a target for the reactive chlorinating species (RCS) produced by myeloperoxidase (MPO). Accordingly, RCS attack of lysosphingolipids was characterized in these studies. It was shown that RCS attack of sphingosylphosphorylcholine results in the formation of 2-hexadecenal and 1-cyano methano phosphocholine. The structures were identified and confirmed predominantly using mass spectrometric analyses. Further, it was demonstrated that RCS attack of another bioactive lysosphingolipid sphingosine 1-phosphate also results in the formation of 2-hexadecenal from its sphingosine base. Using a synthetically prepared, deuterated 2-hexadecenal internal standard, it was determined that 2-hexadecenal quickly accumulated in HDL treated with MPO/RCS generating system. Thus, the present studies characterize the formation of a novel group of lipid products generated following RCS attack of lysosphingolipids.

Cis-syn thymine dimers are the major photoproducts of DNA and are the principal cause of mutations induced by sunlight. To better understand the nature of base pairing with cis-syn thymine dimers, we have synthesized a decamer oligodeoxynucleotide (ODN) containing a cis-syn thymine dimer labeled at the N3 of both T's with 15N by two efficient routes from [3-15N]-thymidine phosphoramidite. In the postsynthetic irradiation route, an ODN containing an adjacent pair of [3-15N]-labeled T's was irradiated and the cis-syn dimer-containing ODN isolated by HPLC. In the mixed building block route, a mixture of cis-syn and trans-syn dimer-containing ODNs was synthesized from a mixture of [3-15N]-labeled thymine dimer phosphoramidites after which the cis-syn dimer-containing ODN was isolated by HPLC. The N3-nitrogen and imino proton signals of an (15)N-labeled thymine dimer-containing decamer duplex were assigned by 2D 1H-15N heterocorrelated HSQC NMR spectroscopy, and the 15N-1H coupling constant was found to be 1.8 Hz greater for the 5'-T than for the 3'-T. The larger coupling constant is indicative of weaker H-bonding that is consistent with the more distorted nature of the 5'-base pair found in solution state NMR and crystallographic structures.

Numerous studies have suggested relationships between myeloperoxidase, inflammation, and atherosclerosis. MPO-derived reactive chlorinating species (RCS) attack membrane plasmalogens releasing alpha-chloro-fatty aldehydes (alpha-Cl-FALDs) including 2-chlorohexadecanal (2-ClHDA). The molecular targets of alpha-Cl-FALDs are not known. The current study demonstrates 2-ClHDA adducts with ethanolamine glycerophospholipids and Fmoc-lysine. Utilizing electrospray ionization mass spectrometry, chlorinated adducts were observed that are apparent Schiff base adducts. Reduction of these Schiff base adducts with sodium cyanoborohydride resulted in a novel, stable adduct produced by the elimination of HCl. NMR further confirmed this structure. 2-ClHDA adducts with ethanolamine glycerophospholipids were also substrates for phospholipase D (PLD). The hydrolysis products were derivatized to pentafluorobenzoyl esters, and further structurally confirmed by GC-MS. Multiple molecular species of 2-ClHDA-N-modified ethanolamine glycerophospholipids were observed in endothelial cells treated with 2-ClHDA. These results show novel Schiff base adducts of alpha-Cl-FALDs with primary amines, which may represent an important fate of alpha-Cl-FALDs.

Novel trihydroxamate-containing peptides were designed to mimic desferrioxamine (Desferal(R), DFO, a naturally occurring siderophore) but possess distinct conformational restrictions and varied lipophilicity to probe structure vs. metal coordination. The synthesis was performed via fragment condensation of hydroxamate-containing oligopeptides such as Fmoc-Leu- Psi[CON(OBz)]-Phe-Ala-Pro-OH and H-Leu-Psi[CON(OBz)]-Phe-Ala-Pro-OBu(t) (Fmoc: 9-fluor enylmethoxycarbonyl; OBz: benzyl; OBu(t): tert-butyl) either in solution or on a solid support. The metal-binding properties were studied by electrospray ionization-mass spectroscopy (ESI-MS), ultraviolet (UV)-visible spectroscopy, and (1)H nuclear magnetic resonance (NMR). Similar to the dihydroxamate analogs previously explored [Biopolymers (Peptide Science), 2003, Vol. 71, pp. 489-515], the compounds with three hydroxamates arrayed at 10-atom intervals, i.e., H-[Leu-Psi[CON(OH)]-Phe-Ala-Pro](3)-OH (P1), cyclo[Leu-Psi[CON(OH)]-Phe-Ala-Pro](3) (P2), and H-[Leu-Psi(CONOH)-Phe-Ala-Pro](2)-Leu-NHOH (P7), exhibited high affinities for intramolecular coordination with Fe(III) and Ga(III). As expected, both P1 and P2 showed higher relative Fe(III)-binding affinities than the corresponding dihydroxamate-containing peptide analogs (P11 and P12). Even though both P1 and P2 did not compete with DFO in the relative metal-binding affinity in both solution and gas phases, P1, P2, and DFO exhibited similar relative binding selectivities to 11 different metal ions including Fe(III), Fe(II), Al(III), Ga(III), In(III), Zn(II), Cu(II), Co(II), Ni(II), Gd(III), and Mn(II). Compared to the other metal ions, they had higher relative binding affinities with Fe(III), Fe(II), Al(III), Ga(III), and In(III). The decreased metal-binding affinities of P1 and P2 in comparison with DFO suggested the conformational restrictions of their backbones perturb their three hydroxamate groups from optimal hexadentate orientations for metal coordination. As detected by ESI-MS, P2 was distinguished from both P1 and DFO by solvation of its Ga(III) and Fe(III) complexes (such as acetonitrile or water), thereby stabilizing the resulting complexes in the gas phase. Noteworthy, P2 led to 69% death rate in Hela cells at a concentration of 50 microM, exhibiting higher cytotoxicity than DFO in vitro despite its much lower affinity for iron. This enhanced toxicity may simply reflect the increased lipophilicity of the cyclic trihydroxamate (P2) together with the improvements in its cell penetration, and/or subsequent intracellular molecular recognition of both side chains and hydroxamate groups. The cytotoxicity was significantly suppressed by precoordination with Ga(III) or Fe(III), suggesting a mechanism of toxicity via sequestration of essential metal ions as well as the importance of curbing the metal coordination before targeting. The potential of such siderophore-mimicking peptides in oncology needs further exploration., ((c) 2006 Wiley Periodicals, Inc.)

Foreign body ingestion is commonly seen in emergency departments. Although most cases have a clear history, foreign bodies in the gastrointestinal tract can be an unexpected finding after operations for other conditions. This study compares the clinical presentations and outcomes for patients requiring or not requiring operations. Between January 1998 and December 2001, 80 patients with foreign body ingestion were included and divided into two groups. Specifically, group 1 patients were managed nonoperatively, and group 2 patients were managed operatively. The patient demographics, symptoms, foreign body ingestion mechanisms, type of diagnostic studies and management, and outcomes were compared between the two groups. Group 1 contained 44 patients, and group 2 contained 36 patients. Group 1 patients were significantly younger, but the incidence of underlying disease and the proportion of patients who ingested foreign bodies intentionally or incidentally was similar in groups 1 and 2. Most of the ingested foreign bodies in group 1 were in the esophagus and stomach, but for group 2 patients they were mostly in the small bowel. Moreover, most of group 1 patients were asymptomatic, which was not the case in group 2. Most group 2 patients had no known history of foreign body ingestion, and diagnoses generally were established during surgery. Neither group of patients displayed any mortality. Nonoperative management of foreign body ingestion usually can succeed in asymptomatic patients with a clear history; however, ingested foreign bodies can cause serious problems for those patients without a clear history of foreign body ingestion.

Background: Major duct injury is the principal determinant of outcome for patients with pancreatic trauma, and there are a number of therapeutic choices available specific to the location of the insult. We report a series of blunt major pancreatic injury cases, with a review of the different procedures used and a discussion of the results., Methods: A total of 48 cases of blunt major pancreatic injury treated during a 10-year period at one trauma center were reviewed retrospectively. Diagnosis and assessment of injury severity were based on imaging studies and proved by surgical findings. Charts were reviewed to establish the mechanism of injury, surgical indications and imaging studies, management strategy, and outcome., Results: Of the 32 grade III patients, 19 underwent distal pancreatectomy with splenectomy, 8 had pancreatectomy with preservation of the spleen, and 2 received a pancreatic duct stent, with the remaining 3 individuals undergoing nonsurgical treatment, pancreaticojejunostomy, and drainage alone, respectively. The grade III complication rate was 60.6%. Of the 14 grade IV patients, 4 underwent drainage alone because of the severity of the associated injuries, 4 underwent pancreaticojejunostomy, 3 had distal pancreatectomy with splenectomy, and 1 underwent distal pancreatectomy. The two remaining patients received a pancreatic duct stent. The grade IV complication rate was 53.8%. The Whipple procedure was performed for two grade V patients; one died subsequently. For all 48 patients, intraabdominal abscess was the most common morbidity (n = 11) followed, in order of prevalence, by major duct stricture (n = 4), pancreatitis (n = 2), pseudocyst (n = 2), pancreatic fistula (n = 1), and biliary fistula (n = 1). All stented cases developed complications, with one dying and three experiencing major duct stricture., Conclusion: The complication rate for our cases of blunt major pancreatic injury was high (62.2%), especially when treatment was delayed more than 24 hours; the same result was also noted for cases transferred from other institutions. Distal pancreatectomy with spleen preservation had a lower complication rate (22.2%) compared with other procedures and is suggested for grade III and grade IV injuries. Magnetic resonance pancreatography was unreliable early after injury but was effective in the chronic stage. Although pancreatic duct stenting can be used to treat posttraumatic pancreatic fistula and pseudocyst, the major duct stricture in the chronic stage of recovery and the risk of sepsis in the acute stage must be overcome.

Matrix metalloproteinases (MMPs) function in homeostatic and repair processes, but unregulated catalysis by these extracellular proteinases leads to the pathological destruction of tissue proteins. An important mechanism for controlling enzyme activity might involve hypochlorous acid (HOCl), a potent oxidant produced by the myeloperoxidase system of phagocytes. We have shown that inactivation of MMP-7 (matrilysin) by HOCl coincides with the formation of a novel oxidation product, WG-4, through modification of adjacent tryptophan and glycine residues and loss of 4 atomic mass units. Here, we use mass spectrometry, UV/visible spectroscopy, hydrogen-deuterium exchange, and NMR spectroscopy to investigate the formation and structure of WG-4. For the initial step, HOCl chlorinates the indole ring of tryptophan. The resulting 3-chloroindolenine generates a previously unknown cyclic indole-amide species, in which tryptophan cross-links to the main chain nitrogen of the adjacent glycine residue to form an aromatic six-membered ring. WG-4 kinks and stiffens the peptide backbone, which may hinder the interaction of substrate with the catalytic pocket of MMP-7. Our observations indicate that specific structural motifs are important for controlling protein modification by oxidants and suggest that pericellular oxidant production by phagocytes might limit MMP activity during inflammation.

Background: Nonoperative management (NOM) of blunt splenic injury (BSI) is currently a well-accepted treatment modality for hemodynamically stable patients. More than 60% of BSI patients can be successfully treated without operation. Old age, high-grade injury, contrast blush, and multiple associated injuries were reported to have a higher failure rate but not to be exclusive of NOM. The purpose of this study was to review the treatment courses and results of a special group of BSI patients with coexistent liver cirrhosis. Factors leading to poor results were analyzed and treatment strategy was proposed accordingly., Methods: During a 5-year period, 487 patients with BSI were treated following a standard protocol. Twelve of them had underlying liver cirrhosis. The medical records, radiographic findings, laboratory data, and operative variables were retrospectively reviewed., Results: Eighty-nine (18%) patients had immediate celiotomy for splenic hemorrhage with unstable hemodynamic status, 59 (12%) had non-spleen-related or nontherapeutic laparotomy, and 339 (70%) patients received NOM initially. Failure of NOM was found in 74 patients (22%). Twelve patients with initial NOM had coexistent liver cirrhosis. The amount of blood transfusion within 72 hours after admission for these 12 patients ranged from 4 to 26 units. Patients with coexistent liver cirrhosis and BSI had a significantly higher NOM failure rate (92% vs. 19%). In NOM failure patients, those with liver cirrhosis had lower Injury Severity Scores, lower splenic injury severity grades, more blood transfusions, and a higher mortality rate. Risk factors for mortality in these patients included a higher Injury Severity Score, a severely elevated prothrombin time (PT), a larger transfusion requirement, and a lower serum albumin level., Conclusion: Liver cirrhosis with subsequent development of portal hypertension, splenomegaly, and coagulopathy makes spontaneous hemostasis of the injured spleen difficult. NOM for BSI patients with coexistent liver cirrhosis carries a high failure and mortality rate. NOM may be successful in only a small group of patients with low-grade single-organ injury and with a normal or mildly elevated PT. Aggressive correction of coagulopathy should be performed in these patients. High-grade splenic injury, multiple associated injuries, and an elevated PT are indicators for early surgery. The mortality rate is high in patients with a severely prolonged PT irrespective of treatment modalities.

The beta-turn is a well-studied motif in both proteins and peptides. Four residues, making almost a complete 180 degree-turn in the direction of the peptide chain, define the beta-turn. Several types of the beta-turn are defined according to Phi and Psi torsional angles of the backbone for residues i + 1 and i + 2. One special type of beta-turn, the type VI-turn, usually contains a proline with a cis-amide bond at residue i + 2. In an aza-amino acid, the alpha-carbon of the amino acid is changed to nitrogen. Peptides containing azaproline (azPro) have been shown to prefer the type VI beta-turn both in crystals and in organic solvents by NMR studies. MC/MD simulations using the GB/SA solvation model for water explored the conformational preferences of azPro-containing peptides in aqueous systems. An increase in the conformational preference for the cis-amide conformer of azPro was clearly seen, but the increased stability was relatively minor with respect to the trans-conformer as compared to previous suggestions. To test the validity of the calculations in view of the experimental data from crystal structures and NMR in organic solvents, [azPro(3)]-TRH and [Phe(2), azPro(3)]-TRH were synthesized, and their conformational preferences were determined by NMR in polar solvents as well as the impact of the azPro substitution on their biological activities.

Background: Because of the difficulties in preoperative diagnosis and controversies in the management, cecal diverticulitis has received much discussion in the literature. There, however, are still many questions that remain unanswered., Methods: During a 5-year period, 112 patients with a clinical diagnosis of cecal diverticulitis were treated. Twenty-seven patients were excluded because of uncertainty in diagnosis or incomplete data collection, leaving 85 patients as the study group. The diagnosis of cecal diverticulitis was made by pathology, surgical findings, or image study., Results: Nonoperative management was applied to 18 patients initially. Three patients had recurrent diverticulitis during follow up. These patients responded satisfactorily to another course of medical treatment. Laparotomy was performed in 67 patients. Acute appendicitis was the preoperative diagnosis in 47 patients (70%). Of the other 20 patients, 6 received operation because of repeated attack of diverticulitis, 7 had preoperative computed tomography (CT) diagnosis of cecal diverticulitis with perforation, 5 had preoperative diagnosis of cecal tumor, and 2 had medical treatment failure. All these 20 patients received right hemicolectomy. In the 47 patients with a preoperative diagnosis of acute appendicitis, 24 received appendectomy, 9 received diverticulectomy, and 14 received right hemicolectomy. Overall, 34 patients received right hemicolectomy, 9 received diverticulectomy, and 24 received appendectomy only. In the right hemicolectomy group, there were 2 deaths with underlying diseases and 5 complications. In the appendectomy group, there was no postoperative mortality, but in 7 patients recurrent diverticulitis developed. Three of them required right hemicolectomy., Conclusions: The natural history of cecal diverticulitis varies from benign and self-limiting to fulminant in the oriental population. Less than 40% (32 of 85) of patients were successfully treated with conservative methods initially and had no recurrence during the follow-up period. We recommend aggressive surgical resection for patients with a definite diagnosis. Adjuvant appendectomy without resection of the lesion should be considered only in uncomplicated patients whose diagnosis is in doubt.

Background: The non-operative management of blunt liver trauma can be applied in almost 80% of patients with this type of injury, with the advantages of the need for fewer blood transfusions, less intra-abdominal sepsis, and a better survival rate, than with the operative approach. However, liver abscess, as a known complication of the non-operative management of blunt liver trauma, is discussed infrequently. Therefore, we herein review our experience and describe this complication in detail., Materials and Methods: From 1995 to 2001, 674 patients were admitted to our hospital due to blunt hepatic trauma. Among these patients, 279 underwent laparotomy and the remaining 395 patients were treated non-operatively. Twenty-two patients were identified as having liver abscess, with 16 of them belonging to the operative group, and six to the non-operative group. A retrospective review of these six patients and their characteristics, as well as pathogenesis, diagnosis, and the management of the liver abscesses, was conducted., Results: These six patients were all male, with a median age of 19.5 years (range 3-24). The median injury severity score was 16.5 (range 9-25); three patients sustained grade-3 hepatic injury, and the other three were grade 4. The main diagnostic tool was abdominal computed tomography, and the abscesses took a median of 6 days (range 1-12) to form and be diagnosed. The abscesses were usually caused by infection from mixed organisms, and an abscess resulting from Clostridium infection developed within 1 day after injury. These abscesses were treated with antibiotics and drainage, and the median length of hospital stay was 26 days (range 8-44), without mortality or long-term morbidity., Conclusion: Liver abscess as a complication of the non-operative management of blunt hepatic trauma is a rare entity, with an incidence of 1.5% (6/395). It is usually seen in severe liver injury (grade 3 and above), but all our patients were all treated successfully, with no mortality. However, prolonged hospitalization may be required in this patient group.

Peptide-bond modification via N-hydroxylation has been explored as a strategy for metal coordination to induce conformational rigidity and orient side chains for specific molecular recognition. N-Hydroxyamides were prepared by reacting N-benzyloxyamino acid esters or amides with Fmoc-AA-Cl/AgCN (Fmoc: 9-fluorenylmethoxycarbonyl; AA: amino acid) in toluene or Fmoc-AA/HATU/DIEA in DMF (HATU: O-(7-azabenzotriazol-lyl)-1,1,3,3-tetramethyluronium hexafluorophosphate; DIEA: N,N-diisopropylethylamine; DMF: N,N-dimethylformamide), followed by deblocking of benzyl protecting groups. Novel linear and cyclic N,N'-dihydroxypeptides were efficiently assembled using Fmoc chemistry in solution and/or on a solid support. As screened by electrospray ionization-mass spectroscopy (ESI-MS), high iron-binding selectivity and affinity were attainable. Compounds having a spacer of two alpha-amino acids between the amino acids bearing the two hydroxamates, i.e., a spacer of 8 atoms, generated 1:1 iron complex species in the gas phase. Moreover, high performance liquid chromatography (HPLC), uv/vis, and (1)H-NMR analyses provided direct evidence for complex formations in solution. Significantly, the representative compound cyclo(Leu-Psi[CON(OH)]-Phe-Ala-Pro)(2) (P8) may serve as a robust metal-binding scaffold in construction of a metal-binding library for versatile metal-mediated molecular recognition., (Copyright 2003 Wiley Periodicals, Inc.)