Micro-organism and Cell Viability on Antimicrobially Modified Titanium

When titanium is anodized by discharge in NaCl solution, both antimicrobial activity and osteoconductivity are conferred. The viability of adherent micro-organisms and cells on antimicrobial titanium remains uncertain. We hypothesized that a thin peroxidation barrier would efficiently destroy adherent bacteria, whereas adherent osteoblastic cells would be viable, since these cells adhere to the surface indirectly though serum proteins. The efficacy of antimicrobial titanium appears to be based on peroxidation, since peroxidation products were detected in parallel with the destruction of bacterial cell-surface structures. The peroxidation effect of antimicrobial titanium was confined to the surface within narrow limits. The viability of osteoblastic cells on the surface was strongly dependent on the presence of serum protein, whereas that of adherent Streptococcus mutans was not affected by the presence of serum proteins. Therefore, differences in the adherent systems used by bacteria and osteoblastic cells are important determinants of their viability on antimicrobial titanium.

Multicenter phase II study of FOLFOX for metastatic colorectal cancer (mCRC) in Japan; SWIFT-1 and 2 study

BACKGROUND/AIMS

This study assessed the efficacy and toxicity of the FOLFOX4 (SWIFT1) and mFOLFOX6 (SWIFT2) regimens in Japanese patients with metastatic colorectal cancer (mCRC).

METHODOLOGY

Patients with mCRC were required to have ECOG performance status of 0 to 1, and to have adequate organ function. Two multicenter Phase II studies (SWIFT1/SWIFT2) were conducted in chemotherapy naive patients with mCRC.

RESULTS

112 patients were enrolled in these studies (SWIFT1: 54 patients / SWIFT2: 58 patients). The disease sites for each study were the colon in 27 patients and 28 patients, and the rectum in 27 patients and 30 patients, respectively. All patients received a median of 8 courses. After a median follow-up period of 35 months, 54 patients and 58 patients were evaluable in the respective studies, and the overall response rate was 50.0% (CR:31 PR:53). The response rate according to the sites of metastasis were as follows: liver, 54.1% (46/85); lung, 17.4% (4/23); and lymph node, 23.3% (7/30). Grade 3/4 neutropenia occurred in 14 patients (12.5%), while Grade 3/4 non-hematological toxicities were observed in 16 patients (31.0%) and Grade 3 neurotoxicity was observed in 6patients (5.4%) and 5 patients (4.5%), respectively.

CONCLUSIONS

FOLFOX4 (SWIFT1) and mFOLFOX6 (SWIFT2) regimens complying with the international standard dosage and schedule can also be administered safely and effectively in Japan.

Role of two component signaling response regulators in acid tolerance of Streptococcus mutans

INTRODUCTION

In bacteria, two-component systems (TCS) involving the products of a histidine kinase gene (hk) and a response regulator gene (rr) play important roles in adaptation to environmental changes. Fourteen hk-rr homologs and one orphan rr homolog were identified in the Streptococcus mutans UA159 genome database. There have been no comprehensive evaluations of the roles of rr homologs in the acid tolerance of S. mutans.

METHODS

The TCS genes (tcs) of S. mutans were designated smtcs01-15. Mutants of S. mutans UA159 with deletions of rr and hk-rr were constructed. Acid tolerance was evaluated by comparing the doubling times at pH 7.2 and pH 5.5 between the wild-type and mutant strains.

RESULTS

Excluding smtcs10 and 12, for which viable mutants could not be obtained, a total of 13 rr deletion mutants were constructed. The rr deletions in smtcs03, 05, 08, and 13 resulted in diminished acid tolerance in comparison with UA159. The hk-rr double-mutants exhibited acid sensitivity levels similar to those of the corresponding rr mutants. The results of the present study reveal the involvement of the rr genes of smtcs03 and 05 in acid tolerance. Deletion of hk and/or rr in smtcs03 generated an acid-sensitive phenotype. In contrast, for smtcs05, while deletion of rr resulted in reduced acid tolerance, a single-deletion of hk had no effect on acid tolerance.

CONCLUSIONS

We implicated two rr genes in the acid tolerance of S. mutans. In particular, smtcs05 is a novel tcs, the sole rr of which is involved in the acid tolerance of S. mutans.

Consecutive national surveys of ABO-incompatible blood transfusion in Japan

BACKGROUND AND OBJECTIVES

Morbidity and mortality from ABO-incompatible transfusion persist as consequences of human error. Even so, insufficient attention has been given to improving transfusion safety within the hospital.

MATERIALS AND METHODS

National surveys of ABO-incompatible blood transfusions were conducted by the Japanese Society of Blood Transfusion, with support from the Ministry of Health, Labor and Welfare. Surveys concluded in 2000 and 2005 analysed ABO-incompatible transfusion data from the previous 5 years (January 1995 to December 1999 and January 2000 to December 2004, respectively). The first survey targeted 777 hospitals and the second, 1355 hospitals. Data were collected through anonymous questionnaires.

RESULTS

The first survey achieved a 77.4% response rate (578 of 777 hospitals). The second survey collected data from 251 more hospitals, but with a lower response rate (61.2%, or 829 of 1355 hospitals). The first survey analysed 166 incidents from 578 hospitals, vs. 60 incidents from 829 hospitals in the second survey. The main cause of ABO-incompatible transfusion was identification error between patient and blood product: 55% (91 of 166) in the first survey and 45% (27 of 60) in the second. Patient outcomes included nine preventable deaths from 1995 to 1999, and eight preventable deaths from 2000 to 2004.

CONCLUSION

Misidentification at the bedside persists as the main cause of ABO-incompatible transfusion.

Sympathovagal effects of spinal anaesthesia with intrathecal or intravenous fentanyl assessed by heart rate variability

BACKGROUND

Although many investigators previously reported the sympathovagal effect of spinal anaesthesia, there is no information about the sympathovagal effects of supplementation with fentanyl. The aim of this study was to evaluate the sympathovagal effects of intrathecal or intravenous fentanyl added to spinal anaesthesia.

METHODS

One hundred and twenty patients undergoing elective transurethral surgery under spinal anaesthesia were randomly allocated to receive intrathecally either isobaric bupivacaine alone (Group B), bupivacaine supplemented with intrathecal (Group Ft) or with intravenous fentanyl (Group Fv). Heart rate variability was estimated using the MemCalc method (Tarawa, Suwa Trust, Japan) before and after spinal anaesthesia.

RESULTS

In all groups, spinal anaesthesia significantly decreased low frequency/high frequency (LF/HF) as a marker of sympathovagal balance. However, patients in Group B with a low block height developed a marked increase in LF/HF after spinal anaesthesia, which was attenuated in Group Ft. Meanwhile, intravenous fentanyl did not attenuate this response.

CONCLUSION

We conclude that sympathetic activation observed in patients with a low block height was attenuated by intrathecal fentanyl but not by intravenous fentanyl.

Cooperation of phosphate monomer and silica modification on zirconia

Ceramic restorations with resin-based adhesive systems have been the focus of recent attention in clinical dentistry. Yttrium-oxide-partially-stabilized zirconia (YPSZ) ceramics have optimized physical properties and exhibit favorable fracture toughness, though their bonding properties are problematic. Although functional phosphate monomers and silica-coating by tribochemical modification were expected to improve the bonding properties between YPSZ ceramics and resin-based adhesives, these two methods remain controversial. This study evaluated the efficiency of silica-coating by tribochemical modification of YPSZ ceramics. The application of phosphate monomer and a silane coupling agent on silica-coated YPSZ was also investigated. The silica-coating of YPSZ ceramics by tribochemical modification was not efficient, given the higher mechanical toughness of the densely sintered ceramics. Stable shear bond strength was achieved on silica-coated YPSZ ceramics with the cooperative interaction of phosphate monomer and silane coupling.

[Intractable pneumothorax secondary to pulmonary metastasis of angiosarcoma]

A 68-year-old male suffered from right pneumothorax and was admitted to our hospital. He had a previous history of angiosarcoma of the scalp, and had received local resection and chemoradiotherapy. Chest computed tomography (CT) on admission revealed right pneumothorax and bilateral multiple thin-walled cavities of the lung. We performed partial resection of right lung. Histopathological examination showed a small metastatic lesion around the thin-walled cavities of the lung. Four months after the 1st lung resection, he suffered left pneumothorax. We performed partial resection of the left lung. Ten days after the 2nd lung resection, left pneumothorax recurred. Nine days later, he also developed right pneumothorax. We performed the 3rd operation for right lung. Thoracoscopy demonstrated multiple bullas in right lung and it showed impossibility for radical surgery. Although surgical resection for pneumothorax secondary to metastatic lung cancer is usually efficient, it is very hard to manage the pneumothorax of metastatic angiosarcoma.

Porphyromonas gingivalis gingipains cause G(1) arrest in osteoblastic/stromal cells

INTRODUCTION

The program for mammalian cell growth and division consists of four successive phases; G(1), S, G(2), and M. Porphyromonas gingivalis may manipulate the host cell cycle to benefit bacterial virulence expression, which likely causes the cell and tissue tropism observed in chronic periodontal infections. We examined P. gingivalis for its effects on cell-cycle modulation in mouse ST2 osteoblastic/stromal cells.

METHODS

Synchronized ST2 cells were infected with P. gingivalis ATCC33277 (wild-type, WT), gingipain-mutants [KDP136 (DeltargpADeltargpBDeltakgp), KDP129 (DeltargpADeltargpB), and KDP133 (Deltakgp)], and a fimbria-deficient mutant (KDP150) for 24 h, then the cell cycle was evaluated using flow cytometry. Cell-cycle-related molecule expression was examined with a microarray, as well as with quantitative real-time polymerase chain reaction and Western blotting assays.

RESULTS

Both the WT and KDP150 strains significantly inhibited cellular proliferation and arrested the cell cycle in the G(0)/G(1) phase, while the expression levels of the cell-cycle regulatory molecules cyclin D and cyclin E were also decreased. In contrast, KDP136 did not show any effects. G(1) arrest was also clearly induced by KDP129 and KDP133, with KDP129 being more effective.

CONCLUSION

The present findings suggest that P. gingivalis gingipains reduce cyclin expression and cause early G(1) arrest, leading to the inhibition of cellular proliferation.

Micromechanical Property Recovery of Human Carious Dentin Achieved with Colloidal Nano-β-tricalcium Phosphate

Reconstitution of carious dentin has been recognized as difficult, because it progresses by loss of collagen polymerization and by demineralization under acidic conditions. Recently, colloidal alkaline nano-calcium phosphate, prepared by electrical discharge in a buffered physiological saline solution, has been shown to be effective in the formulation of a bone-like biocomposite by simply being mixed with acidic collagen solution. It was hypothesized that colloidal calcium phosphate was suitable for the reconstitution of carious dentin. Natural caries lesions in dentin from permanent teeth were exposed to colloidal hydroxyapatite and β-tricalcium phosphate for 10 days. The micromechanical properties of these tissues were evaluated by nano-indentation. The elastic modulus of human carious dentin improved after samples were immersed in colloidal β-tricalcium phosphate. The mineral density of carious dentin exposed to β-tricalcium phosphate increased more than that immersed in hydroxyapatite. However, since it was not directly proportional to micromechanical recovery, mineral density alone was not a sufficient indicator of mechanical behavior.

A greater decrease in blood pressure after spinal anaesthesia in patients with low entropy of the RR interval

BACKGROUND

The objective of this study was to determine whether pre-operative heart rate variability (HRV) estimated using the newly developed MemCalc method predicts hypotension after spinal anaesthesia (SA).

METHOD

Fifty-two patients with American Society of Anesthesiologists physical status I or II, aged 38-84 years, scheduled to undergo elective transurethral surgery were investigated in this study. Ultra short-term entropy (UsEn) as a non-linear index of HRV was estimated before and after SA using the MemCalc method. The patients were then assigned to two groups (Group LO and HI) according to pre-operative UsEn. SA was performed by intrathecal injection of 17.5 mg of isobaric bupivacaine via interlumbar spaces L3-4 or L4-5. After SA, the haemodynamic fluctuations were recorded and compared between the two groups.

RESULTS

SA significantly decreased LF/HF (a ratio of the low frequency component of HRV to that of the high frequency component) but did not affect UsEn. The percentage decrease in systolic blood pressure (SBP) after SA was 11.4 (9.9)% in group HI, whereas it was 17.5 (9.8)% in group LO (P < 0.05). Furthermore, the number of patients who developed hypotension was significantly higher in group LO.

CONCLUSION

SA significantly decreased LF/HF without affecting UsEn. Patients with a low UsEn developed a greater decrease in SBP after SA. Furthermore, the incidence of hypotension after SA was higher in patients with a low UsEn.

Interplay of superconductivity and rattling phenomena in beta-pyrochlore KOs2O6 studied by photoemission spectroscopy

The electronic structure near the Fermi level (EF) of the beta-pyrochlore superconductor KOs2O6 is studied using laser-excited ultrahigh-resolution photoemission spectroscopy. The superconducting gap clearly opens across the superconducting transition (Tc=9.6 K), with the strong electron-phonon coupling value of 2Delta(0)/k B Tc>or=4.56. A fitting analysis identifies clear anomalies at Tp=7.5 K in the temperature dependencies of the superconducting gap size and the quasiparticle relaxation lifetime. These anomalies and the fine spectral structures arising from phonons suggest that the existence of the rattling behavior of K ions significantly affects the superconductivity in KOs2O6.

Lactate quantification by proton magnetic resonance spectroscopy using a clinical MRI machine: A basic study

The purpose of this study was to establish quantification method of lactate concentration by proton magnetic resonance spectroscopy (MRS) carried out using a conventional 1.5-T MRI machine. We used a lactate phantom with known concentrations (1, 1.5, 3, 6, 12 and 14 mmol/L). As a clinical example, a patient with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) was evaluated. Proton MRS was carried out using a clinical 1.5-T super-conducting magnetic resonance whole-body system. Data were acquired by point resolved spectroscopy. A coupling constant of J = 7.35 Hz (2/J = 272 ms) and two long in-phase echo time of 272 ms and 544 ms were used to calculate the T2 relaxation time. The tissue water signal was used as an internal standard to quantify lactate. The correlation coefficient R between the calculated lactate concentrations and the known concentration of lactate was 0.99 with a constant factor of 0.32 (1/3.14). In patients with MELAS, the lactate concentration measured by MRS was 6.2 mmol/kg wet weight, which is similar to the value obtained in previous studies. In the present study, we have established a reliable method for lactate quantification in a phantom study and have shown a sample of clinical case of MELAS.

Imaging of cerebrospinal fluid space and movement of hydrocephalus mice using near infrared fluorescence

We have studied optical imaging of mice cerebrospinal fluid (CSF) space and flow using near infrared (NIR) fluorescence. We applied our method to image CSF space and flow in a mice hydrocephalus model. Hydrocephalus was induced in mice with intracranial injections of transforming growth factor. Hydrocephalic and control mice were imaged using our NIR fluorescence imaging system. Hydrocephalic mice showed diminished intracranial CSF flow. Our system is sufficient to show altered CSF flow in a mouse hydrocephalus model. Optical imaging using near infrared is an effective modality to image CSF space and movement.

Identification and characterization of Asef2, a guanine-nucleotide exchange factor specific for Rac1 and Cdc42

The tumor suppressor adenomatous polyposis coli (APC) is mutated in sporadic and familial colorectal tumors. APC interacts with the Rac1-specific guanine-nucleotide exchange factor (GEF) Asef, which contains an APC-binding region (ABR) in addition to Dbl homology (DH), Pleckstrin (PH) and Src homology 3 (SH3) domains. APC stimulates the GEF activity of Asef, and thereby regulates cell adhesion and migration. Here, we have identified a second Asef, termed Asef2, that shows significant structural and functional similarities to Asef. We found that both the N-terminal ABR and SH3 domains of Asef2 are responsible for its interaction with APC. When expressed in HeLa cells, a mutant Asef2 lacking the ABR and SH3 domains, Asef2-DeltaABR/SH3, induced increases in the levels of the active forms of Rac1 and Cdc42. Full-length Asef2 also showed this activity when co-transfected with truncated mutant APC expressed in colorectal tumor cells. Consistent with this, either Asef2-DeltaABR/SH3 or Asef2 plus truncated mutant APC stimulated lamellipodia formation in MDCK cells and filopodia formation in HeLa cells. Furthermore, RNA interference experiments showed that Asef2 is required for migration of colorectal tumor cells expressing truncated APC. These results suggest that similar to Asef, Asef2 plays an important role in cell migration, and that Asef2 activated by truncated mutant APC is required for aberrant migration of colorectal tumor cells.

Functional characterization of Musca glutamate- and GABA-gated chloride channels expressed independently and coexpressed in Xenopus oocytes

Ligand-gated chloride channels (LGICs) are important targets for insecticides and parasiticides. Genes encoding subunits of two LGICs, a glutamate-gated chloride channel (MdGluCl-alpha) and a gamma-aminobutyric acid (GABA)-gated chloride channel (MdRdl), were cloned from house-flies (Musca domestica L.). These genes were first expressed independently in Xenopus laevis oocytes by cRNA injection in order to investigate the pharmacology of these ligand-gated channels using two-electrode voltage-clamp electrophysiology. It was found that L-glutamate and GABA activated the MdGluCl-alpha homo-oligomers with an EC(50) value of 30 microM and the MdRdl homo-oligomers with an EC(50) value of 101 microM, respectively. Both channels were chloride ion-permeable, and the MdRdl channel was more sensitive to chloride channel blockers, such as gamma-hexachlorocyclohexane (gamma-HCH), fipronil and picrotoxinin, than the MdGluCl-alpha channel. MdGluCl-alpha required only 1-2 days of incubation after cRNA injection to be expressed in oocytes, whereas 4-7 days of incubation was necessary to achieve MdRdl expression. However, when the cRNA of MdGluCl-alpha was injected at a dose of 1% (w/w) 1 day after the injection of the cRNA of MdRdl, a significant increase in the current amplitude of responses to GABA was observed, and the incubation period necessary for MdRdl expression became shorter. These results suggest that MdGluCl-alpha assists in the expression of MdRdl when the two are coexpressed.

Exotic radiation from a photonic crystal excited by an ultrarelativistic electron beam

We report the observation of an exotic radiation (unconventional Smith-Purcell radiation) from a one-dimensional photonic crystal. The physical origin of the exotic radiation is direct excitation of the photonic bands by an ultrarelativistic electron beam. The spectrum of the exotic radiation follows photonic bands of a certain parity, in striking contrast to the conventional Smith-Purcell radiation, which shows solely a linear dispersion. Key ingredients for the observation are the facts that the electron beam is in an ultrarelativistic region and that the photonic crystal is finite. The origin of the radiation was identified by comparison of experimental and theoretical results.