Biomedical subjects

K Komori

Publications and source records attributed to K Komori.

At least 19 recordsLinked to original sources

PubMed2006

Survival benefit of high ligation of the inferior mesenteric artery in sigmoid colon or rectal cancer surgery.

BACKGROUND: The aim of this study was to assess the impact of inferior mesenteric artery (IMA) root nodal dissection before high ligation of the artery on survival in patients with sigmoid colon or rectal cancer. METHODS: Data on 1188 consecutive patients who underwent resection for sigmoid colon or rectal cancer, with high ligation of the IMA, were identified from a prospective database (April 1965 to December 1999). Survival of patients with involvement of nodes along the IMA proximal to the origin of the left colic artery (root nodes, station 253) through the bifurcation of the superior rectal artery (trunk nodes, station 252) was determined. RESULTS: Twenty patients (1.7 per cent) had metastatic involvement of station 253 lymph nodes and 99 (8.3 per cent) had metastases to station 252. The 5- and 10-year survival rates of patients with metastases to station 253 were 40 and 21 per cent, and those for patients with metastases to station 252 were 50 and 35 per cent, respectively. CONCLUSION: High ligation of the IMA allows curative resection and long-term survival in patients with cancer of the sigmoid colon or rectum and nodal metastases at the origin of the IMA.

Adult↗

PubMed2006

Hepatocyte morphology and kinetics after portal vein embolization.

BACKGROUND: Macroscopic volume changes after portal vein embolization (PVE) can be assessed accurately by computed tomography, but histological changes remain poorly understood. The aim of this study was to clarify hepatocyte morphology and kinetics after PVE. METHODS: The resected livers from 25 patients who underwent extended hepatectomy after PVE and five normal livers were examined using hepatocyte paraffin 1 staining for histomorphometric analysis of hepatocytes. Cell kinetics were determined by Ki-67 staining and terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick-end labelling assay. Kupffer cells were examined by CD68 immunostaining. RESULTS: The number of hepatocytes was similar in the embolized lobe, non-embolized lobe and normal liver, but hepatocyte volume was greater in the non-embolized lobe than in the embolized lobe (P = 0.017). The Ki-67 labelling index was higher in the non-embolized lobe (P < 0.001) whereas the apoptotic index was higher in the embolized lobe (P < 0.001). There were more Kupffer cells per unit area in the embolized lobe (P < 0.001). CONCLUSION: Hepatocyte hypertrophy and replication leads to volume enlargement of the non-embolized hepatic lobe, whereas hepatocyte atrophy and apoptosis causes a decrease in volume of the embolized lobe.

Adult↗

PubMed2006

Occurrence of nonylphenol, nonylphenol ethoxylate surfactants and nonylphenol carboxylic acids in wastewater in Japan.

Nonylphenol (NP) is known to be a byproduct of nonylphenol ethoxylates (NPnEO) which are used as detergents in industry. It is important that not only NP but also NPnEO and their related substances are analysed when behaviour of NP in the wastewater treatment process is surveyed. NPnEO are biodegraded to shorter ethoxylate (EO) chain NPnEO or nonylphenol carboxylates (NPnEC) under aerobic conditions, and then biodegraded to NP under anaerobic conditions. NP is one of the suspected endocrine disruptors (ED). Moreover, shorter EO chain NPnEO has greater toxicity than longer EO chain NPnEO. We conducted a field survey of NP and its related substances in 20 wastewater treatment plants (WWTP). The concentrations (median) of NP and its related substances in the WWTPs' influent ranged from 0.1 to 8.3 microg/L, showing NP concentration as the same level as those previously reported. The reduction of the long EO chain NPnEO in the WWTPs was almost complete, while the removal efficiency for the short EO chain NPnEO was less significant than the long EO chain NPnEO, suggesting that the degradation rate of the short EO chain NPnEO was lower than that of the long EO chain NPnEO in the wastewater treatment

Carboxylic Acids↗

PubMed2006

Fate of oestrogenic compounds and identification of oestrogenicity in a wastewater treatment process.

Understanding of the fate of oestrogen and oestrogenic compounds is important in improving the removal efficiency for oestrogens in wastewater treatment plants (WWTPs). In this study an attempt was made to clarify the fate of oestrogen, oestrogen sulphates, and oestrogenic compounds (synthetic oestrogen, nonylphenol and its relatives) by an instrumental analysis, and the fate of oestrogenicity by an in vitro assay. The investigation was conducted in an activated sludge WWTP in winter and summer, focusing on identification of the primary substances that induce oestrogenicity. Wastewater samples were analysed by employing the silica-gel fractionation technique in conjunction with two-step column chromatography. The results revealed that, in winter, the WWTP efficiencies for the removal of nitrogen and oestrogens decreased and the oestrone level increased with the progress of the treatment. Oestrone and oestrogenic substances are likely to circulate between the aeration tank and the final sedimentation tank. In summer, however, these compounds were effectively removed in the WWTP. The results of the column chromatography coupled with the bioassay suggested that E1 and E2 are the predominant contributors to the oestrogenicity in the influent, return sludge and effluent of the WWTP. The measurement by the instrumental analysis supported these findings.

Biological Assay↗

PubMed2006

Effects of antibacterial agents, levofloxacin and clarithromycin, on aquatic organisms.

Contamination of surface waters by pharmaceutical chemicals is an emerging environmental problem. This study evaluated the toxic effects of the antibacterial agents levofloxacin (LVFX) and clarithromycin (CAM), which are widely used in Japan, on aquatic organisms. Ecotoxicity tests using a bacterium, alga and crustacean were conducted. Microtox test using a marine fluorescent bacterium showed that LVFX and CAM have no acute toxicity to the bacterium. From the results of the Daphnia immobilisation test, LVFX and CAM did not show acute toxicity to the crustacean. Meanwhile, an algal growth inhibition test revealed that LVFX and CAM have high toxicity to the microalga. The phytotoxicity of CAM was about 100-fold higher than that of LVFX from a comparison of EC50 (median effective concentration) value. From the Daphnia reproduction test, LVFX and CAM also showed chronic toxicity to the crustacean. Concentrations of LVFX and CAM in the aquatic environment were compared with PNEC (predicted no effect concentration) to evaluate the ecological risk. As a result, the ecological risk of LVFX is considered to be low, but that of CAM is higher, suggesting that CAM discharged into an aquatic environment after therapeutic use may affect organisms in the aquatic environment.

Animals↗

PubMed2006

Occurrence of levofloxacin, clarithromycin and azithromycin in wastewater treatment plant in Japan.

Residual pharmaceutical products in sewage and other water environments have recently become a serious social problem in advanced countries. Among these pharmaceutical products, antibiotics have attracted special attention due to their serious impact on the ecosystem and connections to the emergence of drug-resistant bacteria. Our research intended to develop a new method to analyse the three antibiotics estimated to be released out of the body in large amounts in Japan; levofloxacin (LVFX), clarithromycin (CAM) and azithromycin (AZM), and survey the state of pollution in the sewerage. The concentrations of the water-phase antibiotics LVFX, CAM and AZM were measured in each process of activated sludge process in six wastewater treatment plants. Liquid chromatography tandem mass spectrometry (LC/MS/MS) was used to analyse solutions of the antibiotics after pretreatment with a solid phase extraction. The limits of quantification and the average recoveries for these antibiotics in the influent were 1.2 to 29 ng/L and 46 to 93%, respectively. In the influent, LVFX, CAM and AZM were detected at concentrations of 552, 647 and 260 ng/L, respectively, while their removal efficiencies were 42, 43 and 49%, respectively. Although the CAM and AZM concentrations decreased as the treatment progressed, it was shown that the LVFX concentration increased in activated sludge reactors in some cases. Despite differences in octanol-water partition coefficients among LVFX, CAM and AZM, their removal efficiency showed no major difference. This indicates that this removal phenomenon cannot be explained by simple adsorption by the activated sludge.

Anti-Bacterial Agents↗

PubMed2005

The retroperitoneum protects prosthetic graft material from intraperitoneal contamination: an experimental study.

OBJECTIVES: To evaluate the ability of the retroperitoneum to serve as a barrier, against bacterial contamination, between the peritoneal cavity to the retroperitoneal space. METHODS: Seventy rats had a small piece of knitted Dacron graft placed in the retroperitoneal space and 10(6)-10(9) colony forming unit (cfu) Enterococcus faecalis was injected into the peritoneal cavity. In half the retroperitoneal (RP) group, the retroperitoneum was preserved and in the remainder, the open peritoneal (OP) group, needle holes were created. Grafts were harvested after 1, 4, or 7 days and cultured for E. faecalis. A blood sample was collected from three rats in each group for culture before the graft was harvested. RESULTS: Graft infection did not develop in any rat injected with 10(6) or 10(7) cfu in the RP group, while seven out of the 10 graft cultures of the OP group grew E. faecalis (P = 0.003). In rats injected with 10(8) or 10(9) cfu, five out of the 10 graft cultures in the RP group and eight out of 10 in the OP group grew E. faecalis. All blood cultures were negative when the injected bacterial count was 10(7) cfu or less. One out of the three blood cultures was positive at 10(8) cfu, and all were positive at 10(9) cfu. CONCLUSIONS: These results suggest that an intact retroperitroneum acts as a protective barrier against intraperitoneal bacterial contamination, particularly when blood cultures are negative.

Animals↗

PubMed2004

Photoassociation spectroscopy of laser-cooled ytterbium atoms.

We report the photoassociation spectroscopy of laser-cooled ytterbium atoms in an optical trap. We observed more than 90 photoassociation resonances of vibrational levels in the (1)Sigma(+)(u) state, including 80 consecutive series, up to 490 GHz detuning with respect to the atomic resonance. From the resonance frequencies we derived the atomic radiative lifetime of the (6s6p) 1P1 state to be 5.464+/-0.005 ns, which is about 2 orders of magnitude improvement over previous results. We also observed line broadening of resonances, which is ascribed to the predissociation to the triplet states, and estimated the transition probability to be 0.2. Furthermore, we observed the decrease of the photoassociation signal intensity, from which the scattering length is estimated to be equal to or less than 3 nm.

Journal Article↗

PubMed2004

Healing of implanted expanded polytetrafluoroethylene vascular access grafts with different internodal distances: a histologic study in dogs.

OBJECTIVE: We assessed characteristics of healing, over time, of two types of expanded polytetrafluoroethylene grafts. STUDY DESIGN: An experimental histological study in dogs. METHODS: The graft types studied had the same internal diameter (5 mm) but different internodal distances. In one, the internodal distance was 60 microm in the external surface and 20 microm in the luminal surface. In the other, the internodal distance was 30 microm throughout the material. Sixteen grafts of each type were implanted between the femoral artery and vein in 16 dogs; explanted 1, 2, 4 or 12 weeks later; and examined histologically. RESULTS: In both graft types, infiltrating-cell density and maximum cell-penetration depth increased significantly between 1 and 2 weeks after implantation, but no significant increases occurred after 2 weeks. The number of inflammatory cells peaked 1 week after implantation and decreased significantly by 2 weeks. Subsequently, there were no significant changes in inflammatory cell numbers, suggesting that the inflammatory phase was over by 2 weeks after implantation and the grafts had become attached to surrounding tissue. There were no significant differences between the two graft types in cell density, cell-penetration depth, or number of inflammatory cells at any assessment time. CONCLUSION: Our results provide histologic support for guidelines recommending that synthetic vascular grafts for hemodialysis access should not be cannulated until 2 weeks after implantation. Since increasing the internodal distance to 60 microm in the external surface had no effect on graft healing, methods other than manipulation of internodal distance should be used in developing a graft suitable for early cannulation.

Animals↗

PubMed2004

Effects of atherosclerotic plaque on the enlargement of an experimental model of abdominal aortic aneurysm in rabbits.

PURPOSE: Abdominal aortic aneurysm (AAA) usually is associated with atherosclerosis. We attempted to create an abdominal aortic aneurysm with atherosclerotic plaque in rabbits to investigate the relationship between atherosclerosis and enlargement of AAA. METHODS: An isolated segment of rabbit abdominal aorta was perfused with pancreatic elastase. Animals were fed a cholesterol-enriched diet to induce atherosclerotic plaque formation. Eight animals received perfusion with elastase and were fed a cholesterol-enriched diet (group EC), eight animals received perfusion with elastase and were fed a normal diet (group EN), eight animals received perfusion with saline and were fed a cholesterol-enriched diet (group SC), and eight animals received perfusion with saline and were fed a normal diet (group SN). Four animals served as a sham group. Each animal was killed after aortography at 4 or 12 weeks. The perfused segment was excised and examined histologically. RESULTS: No animal treated with saline and fed normal diet (groups SN) developed either an aneurysm or atherosclerosis. Atherosclerotic plaque was observed in animals fed the cholesterol-enriched diet (groups SC and EC) at 4 weeks, and the plaque had thickened further by 12 weeks. All animals treated with elastase (groups EN and EC) developed an AAA. Maximum internal diameter in groups EN and EC (4.1 mm) was equal at 4 weeks, but at 12 weeks, the diameter was less for group EC than for group EN (4.0 mm versus 4.8 mm, P<0.05). CONCLUSION: Cholesterol-enriched diet following the intra-luminal perfusion of an isolated aortic segment with elastase produced an AAA with atherosclerotic plaque in rabbits. It is likely that the thickened intima with atheroma suppressed continued enlargement of the aneurysm in this model.

Animals↗

PubMed2004

Renal artery clamping and left renal vein division during abdominal aortic aneurysm repair.

OBJECTIVES: To determine whether renal artery clamping and division of the left renal vein affects renal function in the patients who undergo repair of infrarenal abdominal aortic aneurysm (AAA). METHODS: Between 1992 and 2000, 267 patients had open surgery for infrarenal AAA. Of these, 22 (8%) required temporary bilateral (15) or unilateral (7) renal artery clamping. 8 also had the left renal vein divided, three of which were re-anastomosed. RESULTS: Renal artery clamping and/or renal vein divisions did not affect the incidence of complications and long term renal failure. CONCLUSIONS: Clamping of the renal arteries and/or renal vein division during AAA surgery does not in itself compromise short or long term renal function.

Aged↗

PubMed2004

Serial follow-up study of serum testosterone and antisperm antibodies in patients with non-obstructive azoospermia after conventional or microdissection testicular sperm extraction.

Testicular sperm extraction (TESE) combined with intracytoplasmic sperm injection is becoming a first-line treatment even for non-obstructive azoospermia. The current focus of TESE is the identification of seminiferous tubules that contain spermatozoa and minimization of testicular damage. Although microdissection TESE has been introduced as a preferred procedure for sperm retrieval, no serial follow-up studies of testicular damage have been reported. In the present study, we assayed serum testosterone concentrations and for the presence of antisperm antibodies (ASA) for 1 year after conventional multiple TESE or microdissection TESE and compared postoperative testicular damage between procedures. Thirteen patients who underwent conventional multiple TESE and 12 patients who underwent microdissection TESE were included in this study. Serum total and free testosterone concentrations were evaluated before operation and 1, 6 and 12 months after TESE. Serum ASA was also evaluated before and 12 months after TESE. Serum total and free testosterone concentrations in all patients in both groups showed no significant postoperative decrease. A comparison between the two groups of serum total and free testosterone concentrations showed no significant difference (total testosterone, p = 0.2477; free testosterone, p = 0.3098). No incidence of new ASA formation was identified in the present study. In conclusion, TESE procedures cause neither a decrease of serum testosterone nor formation of ASA. Serum testosterone concentration are similar between patients in the conventional multiple TESE and microdissection groups. Therefore, microdissection TESE is safe with respect to testicular damage, particularly for patients with hypogonadism.

Adult↗

PubMed2004

Dementia associated mental and behavioural disturbances in elderly people in the community: findings from the first Nakayama study.

OBJECTIVE: To determine the prevalence of mental and behavioural disturbances associated with dementia in elderly people living in the Japanese community of Nakayama. METHODS: A door to door three phase population survey was carried out on all persons aged 65 years and older living at home. The study included a psychiatric interview, neurological and neuropsychological examination, and cranial computed tomography. Participants with dementia were rated on the neuropsychiatric inventory. RESULTS: Of 1438 inhabitants, 1162 (81.0%) completed the protocol. The prevalence of dementia was 4.8%. Of the 60 participants with dementia (Alzheimer's disease 35%, vascular dementia 47%, and dementia from other causes 17%), 53 (88.3%) had shown one or more mental and behavioural disturbances. Apathy/indifference (56.7%), followed by agitation/aggression (35%), aberrant motor behaviour (31.7%), and irritability (31.7%) were the common symptoms. More productive (positive) symptoms such as delusions and aberrant motor behaviour were found in the Alzheimer group than in the vascular dementia group. CONCLUSIONS: A wide range of dementia associated mental and behavioural disturbances developed in the majority of community dwelling individuals with dementia. The findings suggest that a screening programme focusing on identifying these symptoms should be included in the physician's diagnostic tools for dementia.

Affect↗

PubMed2004

Distribution of estrogen, nonylphenol and its derivatives in the sediments of a shallow lake.

To determine the distribution of endocrine disruptors (EDs) in lake water and sediments, field investigation was conducted in Lake Teganuma, which is a shallow eutrophic lake, highly affected by human activities. Concentration profiles with sediment depths were obtained for estrogens, nonylphenol (NP), nonylphenol ethoxylates (NPnEO), and nonylphenoxy acetic acids (NPnEC). 17beta-Estradiol (E2) was rarely detected, and 17alpha-ethynylestradiol (EE2) and estriol (E3) were undetected at all depths (0-98 cm) in any of the sediment core samples. The sediment concentrations of estrone (E1) ranging from <0.05 to 3.5 microg/kg-dry wt. and NP from 11.8 microg/kg-dry wt. to 21 mg/kg-dry wt. were obtained. The maximum concentrations of NPnEO and NPnEC in the core sediments were 2.5 mg/kg-dry wt. and 1.4 mg/kg-dry wt., respectively. The EDs concentrations are higher at the inlet than at the outlet (except for NP) in the sediments near the surface. The longitudinal distributions of E1, NPnEO and NPnEC in the benthic sediments show that the concentrations are highest at the inlet, and are fairly constant at lower levels towards the downstream. The obtained results also indicate that NP tends to be adsorbed to the organic particulates produced by algae, followed by sedimentation near the outlet of the lake.

Estradiol Congeners↗

PubMed2004

Analysis and occurrence of estrogen in wastewater in Japan.

This paper describes an analytical procedure for free estrogens and their conjugates in domestic wastewater. The procedure demonstrated in this study is innovative in terms of levels of detection and quantification of the following substances: estrone (E1); 17beta-estradiol (E2); 17alpha-ethynylestradiol (EE2); estriol (E3); estrone-3-sulfate (E1-S); beta-estradiol 3-sulfate (E2-S); estriol 3-sulfate (E3-S); estrone beta-D-glucuronide (E1-G); beta-estradiol 17-(beta-D)-glucuronide (E2-G); estriol 3-(beta-D)-glucuronide (E3-G); beta-estradiol 3-sulfate 17-glucuronide (E2-SandG); and estradiol 3,17-disulfate (E2-diS). The detection limits of this method ranged from 0.1 to 1.4 ng/l. The recovery efficiencies of the estrogens in the analysis from influent and effluent of the secondary settling tank in a wastewater treatment plant (WWTP) were higher than 94% for the free estrogens, but were less than 50% for the conjugated estrogens. The field study using this method was conducted at twenty WWTPs in Japan. The median concentrations of the estrogens ranged from ND to as high as >100 ng/l. In the influent and secondary effluent samples, the concentrations of E1, E2 and E3 were the same levels as those previously reported. We found that the conjugated estrogens exist at higher concentrations in the influent and the secondary effluent than in the other studies, and that the concentrations of the conjugated estrogens were higher than those of the free estrogens.

Environmental Pollutants↗

PubMed2003

High-density trapping of cold ytterbium atoms by an optical dipole force.

We have succeeded in trapping a high density of rare-earth atom of ytterbium (Yb) in a crossed far-off resonance trap. The peak density reaches more than 10(14) cm(-3). With a new method of a delayed crossed far-off resonance trap, we have elucidated that the atoms became concentrated into the cross region by atom-atom collisions. We trap fermionic Yb atoms in the same way as bosonic ones.

Journal Article↗

PubMed2002

Alternative approach to endoluminal treatment of an anastomotic aneurysm.

Conventional surgical treatment of patients with an anastomotic aneurysm can be a surgical challenge if severe adhesions are present. We report here effective treatment of an anastomotic aneurysm using an endoluminal stent graft. A 71-year-old man had undergone an aorto-bifemoral bypass for Leriche's syndrome in 1989 and partial gastrectomy for cancer in 1996. He was admitted to our department with a pseudoaneurysm of a proximal anastomosis located at the aorta below both renal arteries. Based on his medico-surgical history, we considered that an endovascular stent should be placed. This graft composed of an UBE(UBE-WOVEN GRAFT) graft and self-expandable Z stents were introduced through the right limb of the bifurcated graft previously implanted, then were placed using the delivery system while advancing under fluoroscopic control, using a pusher rod. Endoleakage was not evident and the postoperative course was uneventful. An endovascular graft is one alternative approach for treating patients with an anastomotic aneurysm as it is less invasive. This procedure proved satisfactory for this patient.

Aged↗

PubMed2001

The archaeal DNA primase: biochemical characterization of the p41-p46 complex from Pyrococcus furiosus.

We characterized the primase complex of the hyperthermophilic archaeon, Pyrococcus furiosus. The two proteins, Pfup41 and Pfup46, have similar sequences to the p48 and p58 subunits, respectively, of the eukaryotic DNA polymerase alpha-primase complex. Unlike previously reported primases, the Pfup41 preferentially utilizes deoxyribonucleotides for its de novo synthesis, and moreover, it synthesizes up to several kilobases in length in a template-dependent manner (Bocquier, A., Liu, L., Cann, I., Komori, K., Kohda, D., and Ishino, Y. (2001) Curr. Biol. 11, 452-456). The p41-p46 complex showed higher DNA binding activity than the catalytic p41 subunit alone. In addition, the amount of DNA synthesized by the p41-p46 complex was much more abundant and shorter in length than that by Pfup41 alone. The activity for RNA primer synthesis, which was not detected with Pfup41, was observed from the reaction using the p41-p46 complex in vitro. The in vitro replication of M13 single-stranded DNA by the P. furiosus proteins was stimulated by ATP. Observation of the labeled primers by using [gamma-(32)P]ATP in the substrates suggests ATP as the preferable initiating nucleotide for the p41-p46 complex. These results show that the primer synthesis activity of Pfup41 is regulated by Pfup46, and the p41-p46 complex may function as the primase in the DNA replication machinery of P. furiosus, in a similar fashion to the eukaryotic polymerase alpha-primase complex.

Adenosine Triphosphate↗