Dynamical footprint of falcipain-2 catalytic triad in hemoglobin-β-bound state

Falcipain-2 (FP-2) is a member of papain family of cysteine proteases and the major hemoglobinase of the hemoglobin detoxification and hemozoin polymerization complex localized in the food vacuole of the plasmodium species. FP-2 is currently gaining clinical significance as the drug target of choice in combating malaria epidemic. Here, a theoretical FP-2/hemoglobin complex has been proposed and the dynamical footprint and energetics of binding have been investigated using molecular and quantum mechanics approaches. The mapped interaction interface comprises residues 34-51 of hemoglobin and cysteine-42/histidine-174/glutamine-36/asparagine-173/204 and subsites S1, S1', and S3 of FP-2. In hemoglobin-bound FP-2, asparagine-173 preferentially partners histidine-174, while glutamine-36 is preferred in ligand-free state. Cysteine-42 exhibits dihedral switch from 110° to 30° in free and bound states, respectively, with exclusion of water from the binding core upon hemoglobin binding. Hemoglobin similarly exhibits high occupancy within .2 nm distance with charged amido acid-rich subsites S1 and S3 of FP-2 functioning in tandem to reduce conformational flexibility of hemoglobin and facilitate the formation of a stabilizing anti-parallel β-sheet between Leucine-172-valine-176 of FP-2 and phenylalanine-45-asparate-47 of hemoglobin and to overcome the + 1.13e + 5 eV activation energy required to optimize the FP-2/hemoglobin-β conformation that precedes hydrolysis.

Prognostic nomogram for nonresectable pancreatic cancer treated with gemcitabine-based chemotherapy

Background:

A nomogram is progressively being used as a useful predictive tool for cancer prognosis. A nomogram to predict survival in nonresectable pancreatic cancer treated with chemotherapy has not been reported.

Methods:

Using prospectively collected data on patients with nonresectable pancreatic cancer receiving gemcitabine-based chemotherapy at five Japanese hospitals, we derived a predictive nomogram and internally validated it using a concordance index and calibration plots.

Results:

In total, 531 patients were included between June 2001 and February 2013. The American Joint Committee on Cancer (AJCC) TNM stages were III and IV in 204 and 327 patients, respectively. The median survival time of the total cohort was 11.3 months. A nomogram was generated to predict survival probabilities at 6, 12, and 18 months and median survival time, based on the following six variables: age; sex; performance status; tumour size; regional lymph node metastasis; and distant metastasis. The concordance index of the present nomogram was higher than that of the AJCC TNM staging system at 12 months (0.686 vs 0.612). The calibration plots demonstrated good fitness of the nomogram for survival prediction.

Conclusions:

The present nomogram can provide valuable information for tailored decision-making early after the diagnosis of nonresectable pancreatic cancer.

Effects of azelnidipine on uric acid metabolism in patients with essential hypertension

PURPOSE

To examine effects of a long-acting calcium channel blocker (CCB) azelnidipine on uric acid metabolism in hypertensive patients.

METHODS

Azelnidipine was administered to 72 patients at a daily dose of 8 mg or 16 mg. In 22 cases out of the 72 patients, a different CCB was switched to azelnidipine. Blood pressure was measured and biochemical parameters of blood and urine were evaluated before and 2-3 months after the administration.

RESULTS

Azelnidipine significantly decreased both systolic and diastolic blood pressure and the heart rate. It decreased both serum urate levels and the urinary uric acid to creatinine ratio (Uur/Ucr), but did not affect the uric acid clearance to creatinine clearance ratio (Cur/Ccr). Azelnidipine decreased both Uur/Ucr and Cur/Ccr in patients with Uur/Ucr ≥ 0.5 or ≥ 0.34, although it did not change these clearance parameters in patients with Uur/Ucr <0.5 or <0.34. Azelnidipine decreased the serum urate levels and Uur/Ucr in hyperuricemic patients with uric acid levels ≥ 7.0 mg/dL in males and ≥ 6.0 mg/dL in females. It did not change these parameters in normouricemic patients with serum urate levels <7.0 mg/dL in males and <6.0 mg/dL in females. Azelnidipine decreased Uur/Ucr and Cur/Ccr in hyperuricemic patients with normal or over excretion of uric acid, although it did not change these clearance parameters in hyperuricemic patients with uric acid hypoexcretion.

CONCLUSIONS

Azelnidipine decreased the serum urate acid levels and Uur/Ucr, and this response was most prominent in hyperuricemic patients or patients with normal and over excretion of uric acid.

Ultrasound-guided single shot caudal block anesthesia reduces postoperative urinary catheter-induced discomfort

BACKGROUND

Urinary catheter-induced discomfort during the postoperative period can be distressing, and sometimes results in severe restlessness and agitation, especially in middle-aged and elderly male patients. Recent advances in ultrasound technology have increased the consistency, safety, and ease of a caudal block even in older patients. We speculated that an ultrasound-guided caudal block would be reliable and safe as treatment for such postoperative discomfort.

METHODS

Adult male patients (ASA I-II) undergoing cervical laminoplasty were allocated to either the caudal block (CB, N.=24) or non-block (NB, N.=24) group. Following anesthesia induction, urinary catheterization was performed using a 16 French Foley catheter. Thereafter, an ultrasound-guided caudal block was performed with 8 ml of 0.3% ropivacaine and 100 µg of fentanyl for patients in group CB, while group NB did not receive a caudal block. We assessed urinary catheter-induced discomfort as mild, moderate, or severe at 0, 2, 6, 10, and 18 hours after surgery, and compared the incidence and severity of discomfort between the groups using a randomized double-blind design.

RESULTS

All caudal blocks were successfully performed with 1 or 2 needle insertions. The incidence of urinary catheter-induced discomfort was significantly reduced in group CB as compared to NB at 0, 2, and 6 hours, while severity was also reduced at 0 and 2 hours. No patient required re-catheterization due to urinary retention after catheter removal. There were no other complications related to the caudal block.

CONCLUSION

Preoperative ultrasound-guided single shot caudal block anesthesia safely reduced postoperative urinary catheter-induced discomfort in our male patients.

A comparative study on the effectiveness of losartan/hydrochlorothiazide and telmisartan/hydrochlorothiazide in patients with hypertension

PURPOSE

Long-term effects of a low-dose hydrochlorothiazide (HCTZ) with losartan (LOS) on uric acid (UA) metabolism as well as glucose metabolism have been studied in hypertensive patients in comparison with those of a low-dose HCTZ with telmisartan (TEL).

METHOD

Fifty-nine hypertensive patients were allocated to a combination therapy with either losartan (50 mg/day)/HCTZ (12.5 mg/day) (LOS + HCTZ group: n = 37) or telmisartan (40 mg/day)/HCTZ (12.5 mg/day) (TEL + HCTZ group: n = 22), respectively. Before and 1 year after the treatment, blood pressure and biochemical parameters of blood and urine were evaluated.

RESULTS

Both systolic and diastolic blood pressures significantly decreased in two groups, without any statistical differences among them. LOS + HCTZ caused no changes in the serum UA level or the ratio of UA clearance to creatinine clearance (CUA/Ccr), whereas TEL + HCTZ significantly increased the serum UA level and reduced CUA/Ccr. LOS + HCTZ did not influence CUA/Ccr in patients with their serum UA below 5.4 mg/dl, while LOS + HCTZ significantly increased CUA/Ccr in patients with their serum UA above 5.5 mg/dl. TEL + HCTZ significantly reduced CUA/Ccr in patients with their serum UA below and above 5.4 mg/dl to increase serum UA level significantly. Neither combination therapies caused any changes in fasting plasma glucose, HbA1c and HOMA-R. In patients with their serum UA level above 5.4 mg/dl, TEL + HCTZ increased HOMA-R, whereas LOS + HCTZ did not.

CONCLUSIONS

LOS + HCTZ did not influence UA metabolism as well as glucose metabolism, likely because of inhibitory action of losartan on URAT1, although TEL + HCTZ were accompanied with impairment of the UA metabolism and glucose metabolism.

A vasodilating β1 blocker celiprolol inhibits muscular release of uric acid precursor in patients with essential hypertension

Although nonvasodilating β1 blockers increase the levels of uric acid in serum, it is not known whether vasodilating β1 blockers have a similar effect. In the present study, we evaluated the effect of celiprolol on the release of hypoxanthine, a uric acid precursor, from muscles after an exercise. We used the semi-ischemic forearm test to examine the release of lactate (ΔLAC), ammonia (ΔAmm), and hypoxanthine (ΔHX) before and 4, 10, and 60 min after an exercise in 18 hypertensive patients as well as 4 normotensive subjects. Before celiprolol treatment, all the levels of ΔHX and ΔAmm, and ΔLAC were increased by semi-ischemic exercise in hypertensive patients, and the increases were remarkably larger than those in normotensive subjects. Celiprolol decreased both systolic and diastolic pressure. It also decreased the levels of ΔHX and ΔAmm without changes in ΔLAC after an exercise. These findings also were confirmed by summation of each metabolite (ΣΔMetabolites). Celiprolol caused a marginal decrease of serum uric acid, but the difference was not statistically significant. On the other hand, nonvasodilating β1 blockers did not suppress the levels of ΔHX and ΔAmm, whereas they significantly increased ΔLAC after an exercise. Celiprolol improved energy metabolism in skeletal muscles. It suppressed HX production and consequently did not adversely affect serum uric acid levels.

Living donor liver transplantation for the patients with portal vein thrombosis: use of an interpositional venous graft passed posteriorly to the pancreatic parenchyma without using jump graft

BACKGROUND

It is difficult to reconstruct the portal vein (PV) using a long interpositional venous graft in living donor liver transplant (LDLT) patients with portal vein thrombosis (PVT), which involves the confluence of the superior mesenteric vein (SMV) and splenic vein (SV). We successfully performed LDLT for three patients with PVT using an interpositional vascular conduit passing posterior to the pancreas without a jump graft.

METHODS

Three of 130 patients who underwent LDLT in our hospital between March 2002 and June 2011 required this technique. After indentifying the location of the SMV, SV and gastrocolic trunk, we ligated and cut the posterior superior pancreaticoduodenal vein and other short branches from the PV. The PV was drawn inferiorly to the pancreas and transected at the confluence of SMV and SV. The external iliac vein or internal jugular vein was sacrificed as a graft for anastomosis to the cut end of the SMV using 6-0 polypropylene running sutures. Then the venous graft was drawn superiorly to the pancreas by passing it posterior to the pancreas parenchyma for anastomosis to the liver graft PV. The interpositional vein was placed posterior to the pancreas where the PV used to be.

RESULTS

All three patients displayed favorable postoperative courses with the Doppler ultrasound demonstrating good portal flow perioperatively. The postoperative portogram demonstrated patency of the vascular graft.

CONCLUSION

This method is easy and helpful to treat portal vein thrombosis, by providing the shortest route between the PV of the donor and the SMV of the recipient.

Effects of cilnidipine on serum uric acid level and urinary nitrogen monoxide excretion in patients with hypertension

The effects of cilnidipine on the serum uric acid level and urinary NO excretion in hypertensive patients were investigated. Blood and urine samples of 16 hypertensive outpatients were collected before and 2 months after cilnidipine therapy (10 mg). The serum uric acid level decreased significantly after cilnidipine treatment, while the uric acid-creatinine clearance ratio was unaffected. The cilnidipine medication produced a significant increase in urinary NO excretion, although amlodipine did not change it significantly. Therefore, cilnidipine has a profound antihypertensive effect and may reduce the serum uric acid level and increase NO production in the kidney.

Detection of antibodies against the non-calcium-dependent epitopes of desmoglein 3 in pemphigus vulgaris and their pathogenic significance

BACKGROUND

Antidesmoglein (anti-Dsg) 3 serum antibody titres are usually correlated with the disease activity of pemphigus vulgaris (PV), but some patients retain high titres even in remission.

OBJECTIVES

The aim of our study was to determine whether anti-Dsg3 antibodies in PV sera recognized calcium (Ca(2+) )-dependent or non-Ca(2+) -dependent epitopes, and to evaluate their pathogenicity.

METHODS

Dsg3 baculoprotein-coated enzyme-linked immunosorbent assay (ELISA) plates were treated with 0.5 mmol L(-1) ethylenediaminetetraacetic acid (EDTA). The binding ability of anti-Dsg3 monoclonal antibodies (mAbs) was analysed. Eight of the 83 patients with PV who were screened had elevated Dsg3 ELISA index values > 00 in remission. The binding ability of these PV sera was analysed. We evaluated the pathogenicity of anti-Dsg3 serum antibodies against the non-Ca(2+) -dependent epitopes using a dissociation assay.

RESULTS

The reactivity of pathogenic anti-Dsg3 mAbs against the Ca(2+) -dependent epitopes diminished markedly in the EDTA-treated ELISA, whereas no such reduction was observed in mAbs against the non-Ca(2+) -dependent epitopes. The sera of all the patients contained antibodies against both Ca(2+) -dependent and non-Ca(2+) -dependent epitopes. In six out of the eight patients, the ratio of antibodies against Ca(2+) -dependent to non-Ca(2+) -dependent epitopes decreased in remission. EDTA-treated Dsg3 baculoproteins adsorbed anti-Dsg3 serum antibodies against the non-Ca(2+) -dependent epitopes, but the remnant PV antibodies retained the ability to induce acantholysis in the dissociation assay.

CONCLUSIONS

We have established an assay to measure indirectly the titres of anti-Dsg3 serum antibodies against the Ca(2+) -dependent epitopes, based on the differences between EDTA-untreated and EDTA-treated ELISA index values, as a routine laboratory test to reflect the pathogenic anti-Dsg3 serum antibody titres more accurately.