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Hiroaki Kikuchi

Publications and source records attributed to Hiroaki Kikuchi.

11 recordsLinked to original sources
PubMed2006

Molecular-dynamics evaluation of fluid-phase equilibrium properties by a novel free-energy perturbation approach: application to gas solubility and vapor pressure of liquid hexane.

A novel free-energy perturbation method is developed for the computation of the free energy of transferring a molecule between fluid phases. The methodology consists in drawing a free-energy profile of the target molecule moving across a binary-phase structure built in the computer. The novelty of the method lies in the difference of the definition of the free-energy profile from the common definition. As an important element of the method, the process of making a correction to the transfer free energy with respect to the cutoff of intermolecular forces is elucidated. In order to examine the performance of the method in the application to fluid-phase equilibrium properties, molecular-dynamics computations are carried out for the evaluation of gas solubility and vapor pressure of liquid n-hexane at 298.15 K. The gas species treated are methane, ethane, propane, and n-butane, with the gas solubility expressed as Henry's constant. It is shown that the method works fine and calculated results are generally in good agreement with experiments. It is found that the cutoff correction is strikingly large, constituting a dominant part of the calculated transfer free energy at the cutoff of 8 A.

Journal Article↗
PubMed2006

Brucella abortusd-alanyl-D-alanine carboxypeptidase contributes to its intracellular replication and resistance against nitric oxide.

Brucella spp. are facultative intracellular pathogens that have the ability to survive and multiply in professional and nonprofessional phagocytes, and cause abortion in domestic animals and undulant fever in humans. However, the mechanism and factors of virulence are not fully understood. In the present study, a D-alanyl-D-alanine carboxypeptidase (DAP) mutant of Brucella abortus failed to replicate in mouse macrophages and HeLa cells, and showed less virulence than the wild type in mice. Under nitric oxide (NO) stress, the growth of the DAP mutant in vitro decreased and it also had less capability to reduce NO than the wild type. Intracellular replication of the DAP mutant was partially restored by pretreatment of macrophages with the NO synthase inhibitor, 1-phenyl-imidazole, and the level of expression of the NO reductase gene, norB, in the DAP mutant was lower than that in the wild type. These results suggest that DAP contributes to resistance against NO and that it is required for the intracellular growth of the bacterium.

Animals↗
PubMed2003

Clinical effect of combination therapy of pioglitazone and an alpha-glucosidase inhibitor.

This study evaluated the efficacy of adding pioglitazone 30 mg to the therapy of patients with type 2 diabetes mellitus whose glycaemic control was poor on an alpha-glucosidase inhibitor (alpha-GI) alone or in combination with a sulphonylurea (SU). The patients (n = 20) had a HbA(1c) level between 7.0 and 12.0% and the fasting plasma glucose was 7.8 mmol/l or higher. They were treated with 30 mg pioglitazone once daily for 16 weeks. The decrease in HbA(1c) at week 16 of treatment was 0.8% (7.8% at baseline dropping to 7.1% at week 16; p < or = 0.01). An increase in leptin was observed 4 weeks after starting the post-study period (p < or = 0.05). Tumour necrosis factor-alpha (TNF-alpha) and body fat percentage did not show any significant alterations. Correlations between the decrease in HbA1c at week 16 and characteristic variables of patients were examined. A correlation with leptin (p = -0.5632, p < or = 0.05) levels was found. Five patients experienced adverse drug reactions, such as oedema, hypoglycaemia and increased creatine phosphokinase (CK), all of which were mild in severity. The addition of pioglitazone in diabetics whose glycaemic control was poor on a alpha-GI alone or with a alpha-GI and SU combination resulted in a significant decrease in HbA1c, and the treatment was well-tolerated. Our findings also suggest that leptin levels could be useful for assessing responders to pioglitazone.

Blood Glucose↗
PubMed2003

[Complete remission of esophageal undifferentiated carcinoma with nedaplatin and 5-FU chemotherapy and endoesophageal brachytherapy].

The patient was a 74-year-old female. Type 1 undifferentiated carcinoma (non-small cell type) was detected in the middle of the thoracic esophagus in August 1999. Although the lesion was diagnosed as T2, N0, and Stage II, the patient was judged to be a poor risk, inoperable case because of a complex past history of renal and respiratory dysfunctions, and dysbasia. Intravenous administration of nedaplatin at 15.8 mg/m2 and 5-FU 590.6 mg/m2 were carried out for 5 consecutive days as chemotherapy. The second cycle of chemotherapy was performed with nedaplatin reduced to 11.8 mg/m2 on the basis of the adverse reactions observed after the first cycle, and PR was attained. As for radiotherapy, additional extracorporeal irradiation was judged to be too dangerous from her history, so endoesophageal brachytherapy alone was added, and CR was obtained. The patient has maintained a CR for more than 2 years after discharge. In this poor risk case with a highly malignant undifferentiated carcinoma, an "individualization strategy" was effective.

Aged↗
PubMed2002

The relation between serum selenium value and cancer in Miyagi, Japan: 5-year follow up study.

To determine the relation between serum selenium (Se) values and the development of cancer, we compared serum Se levels among cancer patients, non-cancer patients, and healthy adults. Serum Se values in cancer patients were examined with respect to primary cancer sites separately. We tracked non-cancer patients and healthy people for 5 years after serum collection to examine whether low Se status is a risk factor for cancer. The mean serum Se values in cancer patients were significantly lower than in non-cancer patients. This difference, however, failed to exist in women 50 years of age and less. In the examination of serum Se values with respect to organs with primary cancer, mean serum Se values for 6 organs were significantly lower than those in non-cancer patients and healthy people. However, female breast cancer patients showed a higher value. During the 5 year follow up, patients who developed cancer had lower values than that in subject who remained non-cancer and sex differences were absent. We were unable to rule out low Se status, as a possible risk factor for cancer, a result supported by our 5-year follow-up. In distribution of non-cancer patients classified by serum Se values, the proportion of patients with low serum Se values (80 ppb or less) was relatively high (12%). If low Se status increases the risk of cancer, low Se status as a risk factor for cancer should be considered even in Japan, where Se intake is sufficient.

Adult↗
PubMed2002

[Assessing liver function by magnetic resonance imaging two-dimensional phase-shift flow measurement of portal venous blood flow after oral intake of glucose].

We have already reported that the ratio of portal venous flow 30 min after oral intake of glucose 75 g to that before intake (PVFR30), measured using pulsed-Doppler ultrasonography (US), correlated significantly with other indicators of liver function and that it could be used to estimate hepatic function before surgery, including liver resection. In this study, to assess the disadvantages of pulsed-Doppler ultrasonography, PVFR30 was measured using two-dimensional (2D) phase-shift (PS) magnetic resonance imaging (MRI). PVFR30 was measured in 17 patients and 7 volunteers: 13 with liver cirrhosis (LC) and 11 without LC (non-LC). Portal venous flow could be measured in all patients without any disturbance of intestinal gas or patient fat, or the high degree of technical skill that Doppler US requires. PVFR30 was significantly lower in the LC group than in the non-LC group. In addition, it correlated significantly with other indicators of liver function, including the indocyanine green clearance test, prothrombin time, hepaplastin test, and cholinesterase activity. These results suggest that PVFR30 measured by 2D PS MRI can be used to estimate liver function, and that this MRI method can be performed more easily than pulsed-Doppler US.

Administration, Oral↗
PubMed1999

Comparative in vitro activity of carbapenem antibiotics against respiratory pathogens isolated in recent years.

We investigated the antibacterial activity of 12 antibiotics, including 4 carbapenems, against 200 strains of respiratory pathogens isolated in 1997, and compared the results with those obtained in 1993. The strains examined were 38 strains of methicillin-susceptible Staphylococcus aureus (MSSA), 32 strains of methicillin-resistant S. aureus (MRSA), 22 strains of penicillin-susceptible Streptococcus pneumoniae (PSSP), 10 strains of penicillin-resistant S. pneumoniae (PRSP), 53 strains of Pseudomonas aeruginosa, 19 strains of Moraxella catarrhalis, and 26 strains of Haemophilus influenzae. In 1993, 100 strains were examined. The minimal inhibitory concentration data of the present study showed that imipenem and panipenem were more active than the other agents against gram-positive bacteria, and that meropenem and biapenem were more active than the other agents against gram-negative bacteria. By comparing these results with those obtained in 1993, it was found that increase of resistance to carbapenem antibiotics was not observed against all the strains tested in this study. Thus, it can be stated that carbapenem antibiotics retain their position as the drug of first choice for severe infections.

Journal Article↗
PubMedDate not supplied

Microwave coagulation therapy for a liver tumor involving the root of the left hepatic vein of the residual liver after extended right hepatectomy.

A 54-year-old man had received low anterior resection for rectal carcinoma and extended right hepatectomy for a metastatic liver tumor. One year later, imaging studies disclosed a metastatic liver tumor in segment 2 of the liver. The residual left hepatic vein was completely invaded by the tumor from the root of the hepatic vein to the confluence of several branches by intraoperative ultrasonography. To resect partial liver with the involved hepatic vein was deemed impossible. Microwave coagulation therapy was performed on the tumor and the involved hepatic vein, as we had established the safety of microwave irradiation to the main hepatic vein without interference of the hepatic venous flow in an experimental study. The patient remains well 40 months after the surgery without recurrent signs. The hepatic venous flow of the irradiated hepatic vein is maintained well according to serial examination of Doppler ultrasonography.

Carcinoma↗
PubMedDate not supplied

Is fenestration a safe treatment for adult polycystic liver disease?: A report of refractory complications.

We report a 67-year-old man with highly symptomatic polycystic liver disease. Fenestration was selected to treat symptoms because the cysts were scattered diffusely and the normal liver volume was limited. Although this patient was relieved from symptoms of liver cysts consequently, several severe postoperative complications including disseminated intravascular coagulation, respiratory failure, liver failure, and biliary leakage occurred resulting in a 6-month postoperative hospital stay. Although various treatments for symptomatic adult polycystic liver disease have been advocated, a definitive treatment remains controversial, especially in diffuse adult polycystic liver disease. Fenestration is one of the alternative treatments for the patients whose cysts are difficult to resect. However high morbidity rate should be carefully assessed, if extensive fenestration is needed to treat diffuse adult polycystic liver disease. Further consideration of appropriate treatments for diffuse adult polycystic liver disease is needed.

Aged↗