26
|
Nonaka K, Tsubouchi H, Okuyama K, Fukao Y, Johnson-Levonas AO, Amatruda JM. Effects of once-daily sitagliptin on 24-h glucose control following 4 weeks of treatment in Japanese patients with type 2 diabetes mellitus. Horm Metab Res 2009; 41:232-7. [PMID: 19253204 DOI: 10.1055/s-0028-1100413] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The aim of the study was to assess the efficacy/safety of once- (100 mg q.d.) or twice-daily (50 mg b.i.d.) sitagliptin 100 mg/day in Japanese patients with type 2 diabetes (T2DM). In this randomized, double-blind study, 80 patients with inadequate glycemic control (HbA1c=6.5-10%; FPG </=15.0 mmol/l) were randomized equally to sitagliptin 100 mg q.d., 50 mg b.i.d. or placebo for 4 weeks. At baseline and Week 4, frequent blood sampling was performed to assess 24-h weighted mean glucose (24-h WMG). Patients in the efficacy analyses (n=76) had a mean baseline HbA1c of 7.7%. At Week 4, least-squares mean changes in 24-h WMG were reduced with sitagliptin 100 mg q.d. and 50 mg b.i.d. versus placebo (-1.9, -1.6, and -0.5 mmol/l, respectively; p<0.001). Sitagliptin significantly improved FPG and 2-h PPG compared to placebo. No significant differences in 24-h WMG, FPG, or 2-h PPG were observed between the sitagliptin groups. Sitagliptin was well tolerated with no hypoglycemic events. In Japanese patients with T2DM, sitagliptin 100 mg/day provided substantial and continuous 24-h glucose-lowering over 4 weeks. The same glucose-lowering efficacy and tolerability were observed with sitagliptin 100 mg/day whether administered as a once-daily or twice-daily regimen. These results support a once-daily dosing regimen in Japanese patients with T2DM.
Collapse
|
27
|
Okuyama K. Structure of collagen-helix motif. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308088727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
28
|
Kaneko F, Kubota H, Kawaguthi T, Okuyama K. Influence of polytypism on polymorphism inn-alkanes: crystallization and thermodynamic stability. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308081269] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
29
|
Noguchi K, Wada M, Okuyama K, Ogawa K. Crystal structures of chitosan and its complexes with hydrogen halides. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308081890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
30
|
Kawaguchi T, Masakiyo K, Jin H, Okuyama K. Electrostatic interaction explains D-staggered structure of collagen. Acta Crystallogr A 2008. [DOI: 10.1107/s010876730808940x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
31
|
Hayashi M, Koychev E, Okamura K, Sugeta A, Hongo C, Okuyama K, Ebisu S. Heat Treatment Strengthens Human Dentin. J Dent Res 2008; 87:762-6. [DOI: 10.1177/154405910808700807] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The flexural strength of Type I collagen, the major organic component of human dentin, increases with heat. We hypothesized that human dentin can be strengthened by heating, which may help prevent fracture of non-vital teeth after restoration. Beam-shaped dentin specimens were obtained from the crowns of human third molars. The dentinal tubular orientations were arranged to run parallel or perpendicular to loading surfaces. The flexural and microtensile strengths of dentin in the parallel specimens were 2- to 2.4-fold greater after being heated between 110°C and 140°C for 1 hr. The stress intensity factors at fracture also increased after specimens were heated. The x-ray diffraction analyses suggested that shrinking of the lateral packing of the collagen triple-helices from 14 Å to 11 Å was the probable cause of the strengthening of heated dentin. We conclude that heat treatment strengthens human dentin.
Collapse
|
32
|
Okuyama K, Wada K, Chihara J, Takayanagi M, Ohno I. Sex-related splenocyte function in a murine model of allergic asthma. Clin Exp Allergy 2008; 38:1212-9. [PMID: 18498415 DOI: 10.1111/j.1365-2222.2008.03015.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND The prevalence and severity of asthma are higher among boys than girls, but the ratios are reversed after puberty. These observations strongly suggest that sex hormones have a role in the pathogenesis of the disease. However, the mechanisms underlying the gender differences in asthma are not fully understood. OBJECTIVE The aim of this study was to investigate sex differences in allergic inflammation in terms of immune function. METHODS Male and female C57BL/6 mice were sensitized and challenged with ovalbumin (OVA). OVA-specific IgE in serum and airway inflammation were compared between sexes. Splenocytes from OVA-sensitized male or female donor mice were transferred to male or female naïve recipient mice. Subsequently, the recipient mice were challenged, followed by the evaluation of OVA-specific IgE and airway inflammation. Cytokines secreted from splenocytes of the sensitized mice were measured. RESULTS The levels of OVA-specific IgE and the allergen-induced airway inflammation were higher in female than in the male mice. The contents of T-helper type 2 (Th2) cytokines, IL-4, IL-5 and IL-13, in the bronchoalveolar lavage fluid from female mice were higher than those from male mice. The airway inflammation in female recipients transferred with splenocytes from female donors was more severe than that in any other combination of recipients and donors. Splenocytes from the sensitized female mice produced more of the Th2 cytokine, IL-5, than those from the sensitized male mice upon stimulation with OVA. CONCLUSION Our findings suggest that the sex difference in allergic airway inflammation may be attributable to the sex difference in not only the hormonal environment but also in the immune cells themselves.
Collapse
|
33
|
Oyabu T, Ogami A, Morimoto Y, Shimada M, Lenggoro W, Okuyama K, Tanaka I. Biopersistence of inhaled nickel oxide nanoparticles in rat lung. Inhal Toxicol 2007; 19 Suppl 1:55-8. [PMID: 17886051 DOI: 10.1080/08958370701492995] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
In order to investigate whether or not airborne nanoparticles with a minimum agglomeration could be used for exposure tests on animals, we developed a nanoparticle generation system and examined the biological effects of the particles in an inhalation study. The generation system was composed of an ultrasonic nebulizer and diffusion dryers, and 30 Wistar male rats were exposed to nickel oxide (NiO) nanoparticles for 4 wk (6 h/day). The geometric mean diameter of the particles and the daily average exposure concentration determined by a combination of a differential mobility analyzer and a condensation nucleus counter in the exposure chamber were 139 +/- 12 nm and 1.0 +/- 0.5 x 10(5) particles/cm3, respectively. At 4 days and 1 and 3 mo after the inhalation, each group of 10 rats were sacrificed and NiO nanoparticles deposited in the lung were determined by chemical analysis and the biopersistence (biological half time) was calculated. The deposited amount of NiO nanoparticles in the rat lungs at 4 days after the inhalation was 29 +/- 4 microg. The retained particle amount in the rat lungs after the inhalation exponentially decreased and the calculated biological half time was 62 days. The histopathological change was not severe just after the inhalation nor throughout the observation time. We concluded that nanoparticles with a minimum agglomeration were dispersed stably in the chamber and exposed to rats for 4 wk and that deposited amounts in the rat lungs and the biopersistence of the particles and the biological response in lung were detected.
Collapse
|
34
|
Ohwada K, Watanabe K, Okuyama K, Ohkawara Y, Sugaya T, Takayanagi M, Ohno I. The involvement of type 1a angiotensin II receptors in the regulation of airway inflammation in a murine model of allergic asthma. Clin Exp Allergy 2007; 37:1720-7. [PMID: 17877756 DOI: 10.1111/j.1365-2222.2007.02815.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND There has been increasing evidence suggesting the involvement of angiotensin II (Ang II) and type 1 Ang II receptors (AT1) in the pathogenesis of bronchial asthma. However, whether such an involvement would promote or suppress the pathophysiology of asthma is controversial. OBJECTIVE The aim of this study was to investigate the role of AT1 in the development of allergic airway inflammation. METHODS Agtr1a+/+ [wild-type C57BL/6 mice (WT)] and Agtr1a-/- mice [AT1a knockout mice (AT1aKO)] with a genetic background of C57BL/6 were systemically sensitized to ovalbumin (OVA), followed by OVA inhalation. OVA-specific IgE in serum obtained just before the inhalation was measured. Bronchoalveolar lavage (BAL) fluid and lung tissues were obtained at various time-points. Cell numbers and differentiation, and cytokine contents in BAL fluids were determined. Peribronchial accumulation of eosinophils and mucus inclusions in the bronchial epithelium were evaluated in lung tissues stained histochemically. Cell numbers and differentiation in BAL fluids of the mice were also determined after lipopolysaccharide (LPS) inhalation. RESULTS The levels of OVA-specific IgE in AT1aKO were significantly higher than those in WT. The numbers of total cell, eosinophils and lymphocytes in BAL fluids 7 days after OVA inhalation in AT1aKO were significantly higher than those in WT. Airway inflammation in bronchial tissues in terms of eosinophil accumulation and mucus hypersecretion in AT1aKO was also stronger than in WT. The contents of IL-4, IL-5 and IL-13, but not IFN-gamma, in BAL fluids of AT1aKO were significantly higher than those of WT. In contrast, neutrophil accumulation in BAL fluids after LPS inhalation was significantly higher in WT than in AT1aKO. CONCLUSION AT1a might be involved in the negative regulation of the development of allergic airway inflammation through polarizing the T-helper (Th) balance towards Th1 predominance. Therefore, it would be of clinical importance to investigate the effects of long-term administration of AT1 blockers on the Th1/Th2 balance in hypertensive patients with bronchial asthma.
Collapse
MESH Headings
- Animals
- Asthma/chemically induced
- Asthma/immunology
- Asthma/physiopathology
- Bronchitis/immunology
- Bronchitis/physiopathology
- Bronchoalveolar Lavage Fluid/chemistry
- Bronchoalveolar Lavage Fluid/cytology
- Bronchoalveolar Lavage Fluid/immunology
- Cell Count
- Cell Differentiation/drug effects
- Cytokines/analysis
- Cytokines/metabolism
- Disease Models, Animal
- Immunoglobulin E/blood
- Lipopolysaccharides/pharmacology
- Lung/drug effects
- Lung/metabolism
- Lung/pathology
- Lymphocytes/drug effects
- Lymphocytes/metabolism
- Lymphocytes/pathology
- Macrophages, Alveolar/drug effects
- Macrophages, Alveolar/metabolism
- Macrophages, Alveolar/pathology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mucus/metabolism
- Neutrophils/drug effects
- Neutrophils/metabolism
- Neutrophils/pathology
- Ovalbumin/administration & dosage
- Ovalbumin/immunology
- Receptor, Angiotensin, Type 1/deficiency
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/physiology
Collapse
|
35
|
Seki T, Nonaka S, Okuyama K, Kimura Y, Ogihara J, Ariga T. A NOVEL FIBRINOLYTIC FACTOR ADIPOMIN REGULATES ADIPOSITY. J Thromb Haemost 2007. [DOI: 10.1111/j.1538-7836.2007.tb02981.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
36
|
Handa Y, Kato H, Hareyama H, Hada K, Kaneuchi M, Oikawa M, Mitamura T, Aono A, Saitoh Y, Okuyama K, Yamashita K. Retrospective analysis of two modes of lymphadenectomy (para-aortic + pelvic vs. pelvic alone) with regard to survival in endometrial cancer: A comparative study of two gynecologic units. J Clin Oncol 2007. [DOI: 10.1200/jco.2007.25.18_suppl.5599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
5599 Background: Patients with endometrial cancer are at high risk of severe post-operative complications because of obesity, diabetes mellitus, and hypertension. The purpose of this study is, for minimizing surgical injury, to determine whether para-aortic lymph nodes dissection is dispensable. Methods: 295 patients received hysterectomy and lymphadenectomy during 1995 - 2005 in two gynecologic units of hospitals, one of where para-aortic lymph nodes (to the level of renal vein) and pelvic lymph node (PAN+PLN) dissection were routinely performed and the other only pelvic lymph node (PLN) were dissected, were enrolled. Their overall survival was retrospectively compared between these units. Results: Mean lymph node count was 58.9±19.7 in 99 patients with PAN+PLN lymphadenectomy, and 36.8±14.6 in 196 patients with PLN alone. 5-year survival was 93.3% in PAN+PLN cases and 92.9% in PLN, with no significant difference. Cases who died of the disease (DD) were 6.1% in PAN+PLN and 9.2% in PLN (relative risk = 0.660). Distribution in each stage was ignorable between two units; however, specific histology types, such as serous, clear cell, and carcinosarcoma, were highly counted in DD of the PLN unit. 5-year survival of only endometrioid type, excluding specific histology types, was 92.9% in PAN+PLN and 95.1% in PLN, and DD were 6.6% in PAN+PLN and 6.0% in PLN (RR = 1.095). Lymph node metastases were found 13.1% in PAN+PLN and 4.1% in PLN. One case was observed PAN-alone metastsis, where histology was serous type. Conclusions: Overall survival in patients received PAN+PLN and PLN dissection is not significantly different in endometrial cancer. It is supposed that only PLN dissection is sufficient and PAN dissection is omittable especially in endometrioid type, however, PAN+PLN lymphadenectomy might be suggestive to reduce death in specific histology types. No significant financial relationships to disclose.
Collapse
|
37
|
Okuyama K, Saito N, Kume E, Noto T, Nagasaki M. Ecabet sodium prevents esophageal lesions induced by the reflux of gastric juice in rats. Inflammopharmacology 2007; 15:90-4. [PMID: 17450449 DOI: 10.1007/s10787-006-1538-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
We investigated the effect of ecabet sodium (ecabet) on rat acute esophageal lesions induced by reflux of gastric juice. Ligation of both pylorus and fore-stomach induced the reflux of gastric juice, decreased the amount of mucus and formed hemorrhagic lesions in the esophageal mucosa. Intragastric injection of ecabet reduced the pepsin activity and prevented both the decrease of mucus amount and formation of lesions. Ecabet enhanced the reduction in lesion formation induced by omeprazole and ranitidine without a change in decreased acid concentration and pepsin activity. Digestion of mucosa and the reduction in mucus were prevented by ecabet in the everted HCl and pepsin treated esophageal sac. These results indicate that ecabet prevents esophageal lesions by inhibiting pepsin activity as well as by protecting mucus from degradation. These further implicate the therapeutic potential of ecabet for prevention/treatment of GERD, especially in combination with a proton pump inhibitor or H(2)-antagonist.
Collapse
|
38
|
Xu G, Okuyama K, Ozawa M, Shimomura M. The Odd-Even Effect on Bilayer Structures of CnAzoCmN+Br−. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/10587259308030136] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
39
|
Xu G, Okuyama K, Shimomura M. Crystal Structures of H-Aggregate of Azobenzene-Containing Amphiphiles, C6AzoC8N+ Br− and C8AzoC10N+ Br−. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/10587259208028722] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
40
|
Yasumori T, Narita H, Matsuda T, Takubo T, Ogawa M, Ishii M, Hara K, Ishii Y, Okuyama K, Fujimoto G, Ochiai H, Kano A, Hasegawa S, Sato K, Taniguchi T. Finasteride 1 mg has no inhibitory effect on omeprazole metabolism in extensive and poor metabolizers for CYP2C19 in Japanese. Eur J Clin Pharmacol 2006; 62:939-46. [PMID: 16953457 DOI: 10.1007/s00228-006-0189-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2006] [Accepted: 07/24/2006] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To examine the inhibitory effect of finasteride 1 mg on the metabolism of omeprazole in genetically determined extensive (EMs) and poor metabolizers (PMs) for CYP2C19 in young healthy Japanese male subjects. METHODS Twenty-four volunteers participated in this study, among whom 12 were homozygous EMs and 12 were PMs for CYP2C19. A single center, controlled, randomized, open, crossover study with a 5 day washout between the two study periods was performed. Each of the six EMs and PMs received a single oral 20 mg dose of omeprazole on day 1 (treatment I). After a 5 day washout period, these subjects received 1 mg of finasteride once a day for three consecutive days, and a single oral 20 mg dose of omeprazole was co-administered on day 3 (treatment II). The 12 other EMs and PMs received treatments I and II in reverse. Plasma samples were collected for up to a 12 hours postdose of omeprazole, and the pharmacokinetic parameters of omeprazole were determined. RESULTS The geometric mean ratio (GMR) for the AUC((0-12 hr)) of omeprazole when co-administered with finasteride/omeprazole alone is 1.13 (90%CI, 1.03, 1.25) and 0.96 (0.88, 1.05) in EMs and PMs, respectively. Finasteride did not significantly alter C(max), T(max) and t(1/2) in both genotypes. CONCLUSION Finasteride 1 mg, widely used for the treatment of androgenetic alopecia in men, did not meaningfully increase omeprazole exposure (20 mg) in both EMs and PMs for CYP2C19. These results indicate that finasteride does not meaningfully inhibit CYP2C19 activity in vivo at the dose of 1 mg.
Collapse
|
41
|
Iwahori T, Takeuchi H, Matsuno N, Johjima Y, Konno O, Nakamura Y, Hama K, Uchiyama M, Ashizawa T, Okuyama K, Nagao T, Abudoshukur M, Hirano T, Oka K. Pharmacokinetic differences between morning and evening administration of cyclosporine and tacrolimus therapy. Transplant Proc 2005; 37:1739-40. [PMID: 15919450 DOI: 10.1016/j.transproceed.2005.02.104] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
We performed 24-hour monitoring of cyclosporine (NEO) and tacrolimus (TAC) blood concentrations, evaluating pharmacokinetic parameters and characterizing circadian variations. The monitoring was performed in 10 instances on nine patients administered NEO and 12 out of 11 patients administered TAC. All cases were administered equally divided doses of drugs twice daily orally. Blood samples were taken before and 1, 2, 3, 4, 6, and 12 hours after NEO or TAC administration in the morning and evening. The pharmacokinetic parameters were compared between morning and evening administrations of both drugs. AUC0-12, AUC0-4, C(max), C2, and C(max)/C(min) of NEO and TAC were significantly lower during the evening compared with morning administrations. C(min) values were significantly higher in the evening. T(max) of NEO was longer in evening, although there was not a significant difference; T(max) of TAC was significantly longer in the evening. We found that NEO and TAC administrations in the evening resulted in reduced bioavailability and delayed absorption when compared with drug administrations in the morning. It was thought that the difference in bioavailability between morning and evening administrations was smaller with TAC, because TAC shows lower peak levels and a flatter blood concentration curve than NEO. C(min) was higher after evening administration than morning because of delayed absorption, though the bioavailability of both drugs decreased in the evening. These results suggest that we have to appreciate apparently high trough levels.
Collapse
|
42
|
Marfo-Owusu E, Okuyama K, Noguchi K. Complexes of non-chiral surfactant molecules with chiral and racemic compounds. Acta Crystallogr A 2005. [DOI: 10.1107/s0108767305084904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
43
|
Takeuchi H, Okuyama K, Konno O, Jojima Y, Akashi I, Nakamura Y, Iwamoto H, Hama K, Iwahori T, Uchiyama M, Ashizawa T, Matsuno N, Nagao T, Hirano T, Oka K. Optimal Dose and Target Trough Level in Cyclosporine and Tacrolimus Conversion in Renal Transplantation as Evaluated by Lymphocyte Drug Sensitivity and Pharmacokinetic Parameters. Transplant Proc 2005; 37:1745-7. [PMID: 15919452 DOI: 10.1016/j.transproceed.2005.02.075] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
We evaluated the relative clinical potency of cyclosporine (CyA) and tacrolimus (Tac) using pharmacodynamic and pharmacokinetic parameters of the drug to obtain the most suitable converting dose and target trough level. The relative pharmacodynamic potency was examined by the mean ratio of drug concentrations giving 50% inhibition of blastogenesis of lymphocytes (IC50) in 66 chronic renal failure patients. The relative potency estimated from clinical pharmacokinetic parameters was examined by the mean ratio of each pharmacokinetic parameter value of CyA versus Tac. The pharmacokinetic parameters were estimated by 12-hour monitoring of drug blood concentrations in seven CyA patients and seven Tac patients. The mean IC50 ratio of CyA and Tac (CyA/Tac of IC50) was 25.1. The mean area under the concentration-time curve (AUC) ratio (CyA/Tac of AUC) was 25.5, the mean trough level (C(min)) ratio (CyA/Tac of C(min)) was 13.2, and the mean dose per body weight ratio was 25.2. The relative potency estimated from AUC that is the most reliable pharmacokinetic parameter for the estimation of clinical efficacy of calcineurin inhibitors appeared to agree with the relative pharmacodynamic potency estimated from IC50. The data suggest that TAC 25-fold more potent than CyA, which represents a suitable converting dose ratio, and that target trough level of CyA is about 13-fold greater than Tac based on CyA/Tac of C(min). We conclude that these relative values may be useful to estimate the suitable dose and target trough levels to convert between CyA and Tac.
Collapse
|
44
|
Nakamura Y, Takeuchi H, Okuyama K, Akashi T, Jojima Y, Konno O, Akashi I, Hama K, Iwahori T, Ashizawa T, Hirano T, Oka K, Matsuno N, Nagao T. Evaluation of Appropriate Blood Level in Continuous Intravenous Infusion From Trough Concentrations After Oral Administration Based on Area Under Trough Level in Tacrolimus and Cyclosporine Therapy. Transplant Proc 2005; 37:1725-7. [PMID: 15919445 DOI: 10.1016/j.transproceed.2005.02.076] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The target blood concentrations of tacrolimus (TAC) and cyclosporine (CYA) during continuous intravenous infusion (C(ss)) have been determined based on clinical experience. However, it is desirable that C(ss) should be set so that the AUC after intravenous infusion is equal to the AUC after oral administration (AUC(po)). Accordingly, we performed 12-hour monitoring of blood concentrations to calculate C(ss) from the blood trough levels (C(TL)) on 15 kidney recipients administered TAC and 12 recipients administered CYA (Neoral). We used an area under the trough level (AUTL) as a new pharmacokinetic parameter. The C(ss) was evaluated from C(TL), AUC(po), and AUTL was calculated to be C(ss) = C(TL) x (AUC(po)/AUTL). In addition, AUTL/AUC(po) ratio and blood peak/trough level ratio (C(max)/C(min)) were examined to compare pharmacokinetics of TAC and CYA. The formula for TAC was C(ss) = C(TL) x 1.40 and that for CYA, C(ss) = C(TL) x 2.55. The calculated target C(ss) of TAC was 1.40 times that of C(TL), which was similar to the present clinical C(TL). In contrast, the calculated target C(ss) of CYA was 2.55 times the C(TL), and therefore an extremely high C(ss) was necessary to obtain a sufficient AUC that will be available after oral administration. Consequently, intravenous administration of CYA twice a day was considered to be more appropriate to obtain sufficient CYA pharmacokinetics, rather than a continuous intravenous administration. We conclude that the formula, C(ss) = C(TL) x (AUC(po)/AUTL) was useful to calculate the target blood concentration of calcineurin inhibitors when changing from continuous intravenous infusion to oral administration of these drugs.
Collapse
|
45
|
Furuta I, Kobayashi N, Fujino T, Kobamatsu Y, Shirogane T, Yaegashi M, Sakuragi N, Cho K, Yamada H, Okuyama K, Minakami H. Bone mineral density of the lumbar spine is associated with TNF gene polymorphisms in early postmenopausal Japanese women. Calcif Tissue Int 2004; 74:509-15. [PMID: 15354858 DOI: 10.1007/s00223-003-0105-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We investigated the relationships between tumor necrosis factor (TNF) gene polymorphism, circulating TNF-alpha (TNF-alpha) concentrations, and bone mineral density (BMD) in the lumbar spine. TNF gene polymorphisms studied were the Nco I polymorphism within the first intron of TNF-beta (TNF-beta) and three single nucleotide polymorphisms in the promoter region of the TNF-alpha gene, at positions -857, -863, and -1031. Allelic variants of the TNF gene were identified using restriction fragment length polymorphism (RFLP) analysis in 177 postmenopausal Japanese women within 10 years after menopause, aged 56.4 +/- 4.5 years (mean +/- SD). A significantly higher prevalence of the alleles TNF-alpha-863A (20.3% versus 9.9%) and TNF-alpha-1031C (21.3% versus 12.4%) was seen in the low BMD group (Z-score < 0, n = 91) than in the high BMD group (0 < Z-score, n = 86). In genotype analysis, although difference did not reach a significant level, women with the rarest allelic variants, i.e., homozygous TNFbl, TNF-alpha-863A, and TNF-alpha-1031C, showed the lowest BMD Z-scores. Women with another rarest allelic variant, TNF-alpha-857T/T had significantly lower BMD Z-scores than did women with TNF-alpha-857C/T or -857C/C. The BMD Z-score decreased significantly with an increase in the total number of such rare alleles. Serum concentrations of TNF-alpha did not differ significantly among groups divided by genotypes. Multiple linear regression analysis revealed that the total number of rare alleles, in addition to the body mass index and the number of years since menopause, was an independent predictor of the BMD. These presumptive functional polymorphisms of the TNF gene may be associated with the lumbar spine BMD in early postmenopausal Japanese women.
Collapse
|
46
|
Azuma Y, Shimada M, Okuyama K. Synthesis of Monodisperse Ultrapure Gallium Nitride Nanoparticles by MOCVD. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/cvde.200304158] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
47
|
Imamura M, Matsukawa T, Ozaki M, Sessler D, Nishiyama T, Okuyama K, Kumazawa T. Nitrous oxide decreases shivering threshold in rabbits less than isoflurane. Br J Anaesth 2003. [DOI: 10.1093/bja/aeg023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
48
|
Imamura M, Matsukawa T, Ozaki M, Sessler DI, Nishiyama T, Okuyama K, Kumazawa T. Nitrous oxide decreases shivering threshold in rabbits less than isoflurane. Br J Anaesth 2003; 90:88-90. [PMID: 12488386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023] Open
Abstract
BACKGROUND Comparable minimum alveolar concentration (MAC) fractions of volatile anaesthetics produce similar thermoregulatory impairment. Nitrous oxide, however, decreases the vasoconstriction threshold less than sevoflurane or isoflurane. We tested the hypothesis that nitrous oxide also decreases shivering threshold less than isoflurane alone or in combination. METHODS Twenty-four rabbits were assigned randomly to one of three 0.3 MAC anaesthetic regimens: (i) nitrous oxide 69%; (ii) nitrous oxide 35% and isoflurane 0.3%; or (iii) isoflurane 0.6%. Body temperature was lowered by perfusing 10 degrees C water through a U-shaped thermode positioned in the colon. Shivering was evaluated by inspection. RESULTS The rabbits anaesthetized with nitrous oxide alone shivered at 37.0 (0.5) degrees C (P<0.01 vs other groups). In those given the nitrous oxide and isoflurane combination, the shivering threshold was 36.4 (0.5) degrees C and that in the isoflurane group was 35.9 (0.4) degrees C. CONCLUSION This study indicates that nitrous oxide reduces the shivering threshold less than isoflurane.
Collapse
|
49
|
Okuyama K, Fukushima R, Wu G, Hongo C, Noguchi K, Tanaka Y, Nishino N. Structural study of collagen model peptide, (Pro-Hyp-Gly)11 at high resolution. Acta Crystallogr A 2002. [DOI: 10.1107/s0108767302097209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
50
|
Noguchi K, Okuyama K. Fiber diffraction studies on polymers using synchrotron radiation source. Acta Crystallogr A 2002. [DOI: 10.1107/s0108767302091572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|