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Biomedical subjects

S Iwai

Publications and source records attributed to S Iwai.

At least 73 records · Page 4Linked to original sources
PubMed2000

Multimodality treatment for patients with hepatocellular carcinoma: a single institution retrospective series.

BACKGROUND: The main therapeutic options for hepatocellular carcinoma (HCC) are hepatic resection, transcatheter arterial embolization (TAE), percutaneous ethanol injection therapy (PEIT) and regional chemotherapy (RC). METHODS: This study retrospectively examined the results of primary treatment of 600 patients with hepatocellular carcinoma selected according to the treatment guidelines of our facility and the results of various combination therapies for recurrent cases. The selection criteria of therapeutic options included the number and size of tumours and hepatic function. RESULTS: The selected primary treatment was hepatic resection for 53.7% of the cases, TAE for 31.5%, PEIT for 8.2% and RC for 6.6%,. The treatment for post-resection recurrence was TAE alone for 62.4% of the cases, TAE + RC for 4.0%, PEIT for 15.2%, TAE + PEIT alone for 4.8%, RC for 8.0% and hepatic resection for 5.6%. The treatment for post-TAE recurrence was TAE alone for 83% of the cases, TAE + PEIT for 9%, TAE + RC for 3%, RC alone for 3% and PEIT alone for 2%. For post-PEIT, therapy was PEIT alone for 71.4% of the cases and PEIT + TAE for 28.6%. For post-RC, RC alone was used for 92.5% and RC + PEIT for 7.5%. The cumulative 3 and 5-year survival rates were 84.4% and 70.6%, respectively for stage I; 61.5% and 48.6% for stage II; 52.7% and 20.5% for stage III; and 22.8% and 17.1% for stage IVA. The cumulative 5 and 7-year survival rates after the primary treatments were 52.% and 40.1%, respectively, for hepatic resection; 46.5% and 38.7%, for TAE; 49.6% and 33.1% for PEIT; and 16.7% and 8.3% for RC. CONCLUSIONS: To improve the treatment results for HCC, early detection is essential and various modalities of treatments in combination should be used for recurrence after primary treatment.

Adult↗
PubMed2000

[1-(13)C]Galactose breath test for quantitative measurement of liver function in a short period.

BACKGROUND: Using a rat model of hepatectomy, we investigated whether the severity of hepatopathy could be quantitatively measured from changes in expiratory (13)CO(2) levels after intravenous administration of [1-(13)C]galactose. MATERIALS AND METHODS: Under nembutal anesthesia, 100 mg/kg [1-(13)C]galactose was administered to rats via the femoral vein, and expiratory (13)CO(2) levels were measured for 60 min. Then, 30, 70 or 90% hepatectomy was performed. In the control group, simple laparotomy was performed. Breath test was conducted 20 min after laparotomy. We examined the correlation of total (13)CO(2) output (S) or single point (13)CO(2) level (SP) every 5 min until 30 min, and at 45 and 60 min with liver weight/body weight (LW/BW) (%). RESULTS: In the control group, the breath test graph reached a plateau level, but in all groups undergoing hepatectomy a plateau level was not reached during measurement. The correlation coefficient between S(30) after [1-(13)C]galactose administration and LW/BW was 0.889 (p< 0.0001). The correlation coefficient between SP(25) after [1-(13)C]galactose administration and LW/BW was highest, 0.923 (p< 0.0001). CONCLUSION: In the breath test with intravenously administered [1-(13)C]galactose, hepatopathy could be evaluated by measuring S(30) and hepatopathy could be more accurately quantitatively evaluated by measuring SP(25) over a short period.

Animals↗
PubMed2000

[Recent advances in the surgical management of esophageal achalasia: modified Girard method and laparoscopic approach].

The standard surgical treatment for esophageal achalasia consists of contraction of the lower esophageal sphincter combined with antireflux repair. This paper describes the techniques of the modified Girard method with a laparoscopic approach. The modified Girard method consists of a long esophagomyotomy, the placement of horizontal transverse sutures to prevent restricture due to reflex, and fundopexy for antireflex repair. We have recently used a laparoscopic approach with the modified Girard method in 10 patients with esophageal achalasia. A total of five trocars were required for the long myotomy in the lower esophagus and repair of the esophagogastric junction. A myotomy of approximately 10-12 cm was made along the lower esophagus and cardia lesion using an electric J-hook. Than transverse sutures were placed on each side of the lower myotomy and the gastric fundus was covered with the upper myotomy with several sutures to diaphlagm and each side of the myotomy lene. Excellent results were achieved, and the patients recovered from surgery more quickly compared with those undergoing an open procedure. However, postoperative manometric findings did not differ between patients who underwent the laparoscopic and open procedures.

Adult↗
PubMed2000

[Bacteria isolated from surgical infections and their susceptibilities to antimicrobial agents. Special references to bacteria isolated between April 1997 and March 1998].

The annual multicenter studies on isolated bacteria from infections in general surgery and their antimicrobial susceptibility have been conducted in 19 facilities in Japan since July 1982. This paper describes the results obtained during the period from April 1997 to March 1998. The number of cases investigated as objectives was 215 for one year. A total of 420 strains (170 strains from primary infections and 250 strains from postoperative infections) were isolated from 174 cases (80.9% of total cases). In primary infections, the isolation rate of anaerobic bacteria was higher than in postoperative infections, while in postoperative infections, those of aerobic Gram-positive bacteria and Pseudomonas aeruginosa were higher than in primary infections. Among aerobic Gram-positive bacteria, the isolation rate of Enterococcus faecalis was the highest, followed by Staphylococcus aureus, which was frequently isolated from postoperative infections. Among anaerobic Gram-positive bacteria, Peptostreptococcus spp. and Streptococcus spp. were commonly isolated from both types of infections. Among aerobic Gram-negative bacteria, Escherichia coli was most predominantly isolated from primary infections, followed by P. aeruginosa, Klebsiella pneumoniae in this order, and from postoperative infections, P. aeruginosa was most predominantly isolated, followed by E. coli and K. pneumoniae. Among anaerobic Gram-negative bacteria, Bacteroides fragilis group was the majority of isolates from both types of infections. We found neither vancomycin nor arbekacin resistant strains of S. aureus, and found no vancomycin resistant strains of Enterococcus spp. The susceptibility of P. aeruginosa against carbapenems did not decline in the year 1997, while resistance of B. fragilis group against cephems advanced increasingly.

Anti-Bacterial Agents↗
PubMed1999

Changes in mRNA levels of fibrinogen subunit polypeptides in rats defibrinogenated with batroxobin.

Batroxobin is a snake venom that is a thrombinlike enzyme used for clinical treatment. We analyzed hepatic mRNA levels for fibrinogen subunit polypeptides and prothrombin by reverse transcription-polymerase chain reaction as well as coagulation and fibrinolysis factors in plasma 1, 3, 5 and 24 hours after Batroxobin treatment (3 BU/100 g) in rats. The mRNA levels of alpha- and beta-chains of fibrinogen were significantly increased with decreases in plasma fibrinogen, alpha2-plasmin inhibitor, and plasminogen levels, while the mRNA levels for prothrombin remained unchanged. These results suggest that fibrinogen mRNA synthesis is regulated by plasma fibrinogen levels in Batroxobin-induced defibrinogenated rats.

Animals↗
PubMed1999

Repair of apurinic/apyrimidinic sites by UV damage endonuclease; a repair protein for UV and oxidative damage.

UV damage endonuclease (UVDE) initiates a novel form of excision repair by introducing a nick imme-diately 5" to UV-induced cyclobutane pyrimidine dimers or 6-4 photoproducts. Here, we report that apurinic/apyrimidinic (AP) sites are also nicked by Neurospora crassa and Schizosaccharomyces pombe UVDE. UVDE introduces a nick immediately 5" to the AP site leaving a 3"-OH and a 5"-phosphate AP. Apyrimidinic sites are more effectively nicked by UVDE than apurinic sites. UVDE also possesses 3"-repair activities for AP sites nicked by AP lyase and for 3"-phosphoglycolate produced by bleomycin. The Uvde gene introduced into Escherichia coli cells lacking two types of AP endonuclease, Exo III and Endo IV, gave the host cells resistance to methylmethane sulfonate and t-butyl hydroperoxide. We identified two AP endonuclease activities in S.pombe cell extracts. Besides cyclobutane pyrimidine dimers and 6-4 photoproducts, N. crassa UVDE also nicks Dewar photoproducts. Thus, UVDE is able to repair both of the major forms of DNA damage in living organisms: UV-induced DNA lesions and AP sites.

Apurinic Acid↗
PubMed1999

Characterization of DNA recognition by the human UV-damaged DNA-binding protein.

The UV-damaged DNA-binding (UV-DDB) protein is the major factor that binds DNA containing damage caused by UV radiation in mammalian cells. We have investigated the DNA recognition by this protein in vitro, using synthetic oligonucleotide duplexes and the protein purified from a HeLa cell extract. When a 32P-labeled 30-mer duplex containing the (6-4) photoproduct at a single site was used as a probe, only a single complex was detected in an electrophoretic mobility shift assay. It was demonstrated by Western blotting that both of the subunits (p48 and p127) were present in this complex. Electrophoretic mobility shift assays using various duplexes showed that the UV-DDB protein formed a specific, high affinity complex with the duplex containing an abasic site analog, in addition to the (6-4) photoproduct. By circular permutation analyses, these DNA duplexes were found to be bent at angles of 54 degrees and 57 degrees in the complexes with this protein. From the previously reported NMR studies and the fluorescence resonance energy transfer experiments in the present study, it can be concluded that the UV-DDB protein binds DNA that can be bent easily at the above angle.

Base Sequence↗
PubMed1999

The XPV (xeroderma pigmentosum variant) gene encodes human DNA polymerase eta.

Xeroderma pigmentosum variant (XP-V) is an inherited disorder which is associated with increased incidence of sunlight-induced skin cancers. Unlike other xeroderma pigmentosum cells (belonging to groups XP-A to XP-G), XP-V cells carry out normal nucleotide-excision repair processes but are defective in their replication of ultraviolet-damaged DNA. It has been suspected for some time that the XPV gene encodes a protein that is involved in trans-lesion DNA synthesis, but the gene product has never been isolated. Using an improved cell-free assay for trans-lesion DNA synthesis, we have recently isolated a DNA polymerase from HeLa cells that continues replication on damaged DNA by bypassing ultraviolet-induced thymine dimers in XP-V cell extracts. Here we show that this polymerase is a human homologue of the yeast Rad30 protein, recently identified as DNA polymerase eta. This polymerase and yeast Rad30 are members of a family of damage-bypass replication proteins which comprises the Escherichia coli proteins UmuC and DinB and the yeast Rev1 protein. We found that all XP-V cells examined carry mutations in their DNA polymerase eta gene. Recombinant human DNA polymerase eta corrects the inability of XP-V cell extracts to carry out DNA replication by bypassing thymine dimers on damaged DNA. Together, these results indicate that DNA polymerase eta could be the XPV gene product.

Alleles↗
PubMed1999

Xeroderma pigmentosum variant (XP-V) correcting protein from HeLa cells has a thymine dimer bypass DNA polymerase activity.

Xeroderma pigmentosum variant (XP-V) represents one of the most common forms of this cancer-prone DNA repair syndrome. Unlike classical XP cells, XP-V cells are normal in nucleotide excision repair but defective in post-replication repair. The precise molecular defect in XP-V is currently unknown, but it appears to be a protein involved in translesion synthesis. Here we established a sensitive assay system using an SV40 origin-based plasmid to detect XP-V complementation activity. Using this system, we isolated a protein from HeLa cells capable of complementing the defects in XP-V cell extracts. The protein displays novel DNA polymerase activity which replicates cyclobutane pyrimidine dimer-containing DNA templates. The XPV polymerase activity was dependent on MgCl2, sensitive to NEM, moderately sensitive to KCl, resistant to both aphidicolin and ddTTP, and not stimulated by PCNA. In glycerol density gradients, the activity co-sedimented with a 54 kDa polypeptide at 3.5S, indicating that the monomeric form of this polypeptide was responsible for the activity. The protein factor corrected the translesion defects of extracts from three XPV cell strains. Bypass DNA synthesis by the XP-V polymerase occurred only in the presence of dATP, indicating that it can incorporate only dATP to bypass a di-thymine lesion.

Aphidicolin↗
PubMed1999

Benzimidazolium triflate-activated synthesis of (6-4) photoproduct-containing oligonucleotides and its application.

In the solid-phase synthesis of oligonucleotides containing the pyrimidine(6-4)pyrimidone photoproduct using a dinucleotide building block, considerable amounts of by-products were found as the chain length increased. The by-products were the major product when a 49mer was synthesized on a 40 nmol scale. It was assumed that these by-products were formed by the coupling of phosphoramidites with the N3 imino function of the 5' component of the (6-4) photoproduct. We examined imidazolium triflate and benzimidazolium triflate to find an alternative activator for DNA synthesis. Imidazolium triflate prevented by-product formation to some extent, but the coupling yields were low. Benzimidazolium triflate was comparable to tetrazole in coupling efficiency and reduced by-product formation to a great extent, without modification of the synthesizer program. The obtained 49mer was used to detect proteins that recognize UV-damaged DNA in HeLa cell extracts. Two major protein-DNA complexes were found when a 49mer duplex was used as probe, while a 30mer duplex failed to detect one of them. This application showed the usefulness of long chain 'damaged' oligonucleotides in biochemical studies.

Benzimidazoles↗
PubMed1999

Proposition for assessment of quantitative whole-body autoradiography.

To assess recent improvements in quantitative whole-body autoradioluminography (QWBA), the entire QWBA procedure was divided into five processes. Each process was then investigated carefully to determine whether there were any problems in defining a clear standard operating procedure. Results show that use of two instruments, Macro-Cut, Leica, Germany, and the Bioimaging Analyzer with IP, Fuji Photo Film, was essential to produce macroautoradiographs for QWBA data. The remaining problems include the process for freezing the animal carcass and the process for freeze-drying or lyophilizing the frozen sections of the biomaterials. In addition, a desirable standard operating procedure (SOP) must be developed for assessing QWBA. This article proposes satisfactory SOPs with sufficient clarification and experimental proofs to ensure regulatory compliance for the QWBA technique.

Animals↗
PubMed1999

13CO(2) peak value of L-[1-(13)C]phenylalanine breath test reflects hepatopathy.

BACKGROUND: Using a rat model of hepatectomy, we investigated whether the severity of hepatopathy could be quantitatively measured from changes in expiratory (13)CO(2) levels after intravenous administration of L-[1-(13)C]methionine or L-[1-(13)C]phenylalanine. MATERIALS AND METHODS: Under nembutal anesthesia, 30 mg/kg L-[1-(13)C]phenylalanine or 40 mg/kg L-[1-(13)C]methionine was administered to rats through the femoral vein, and expiratory (13)CO(2) levels were measured for 15 min. A 30, 70, or 90% hepatectomy was performed. In the control group, simple laparotomy was performed. Breath test was conducted 20 min after laparotomy. We examined the correlation of the total (13)CO(2) output over 15 min or peak (13)CO(2) level with liver weight/body weight (%). RESULTS: In breath test graphs, L-[1-(13)C]methionine did not show any peak level during measurement. L-[1-(13)C]phenylalanine showed a specific peak level 6 +/- 1 min after administration. The correlation coefficient between total (13)CO(2) output over 15 min after L-[1-(13)C]methionine administration and liver weight/body weight was 0.922 (P < 0.001). The correlation coefficient between total (13)CO(2) output over 15 min after L-[1-(13)C]phenylalanine administration and liver weight/body weight was 0.883 (P < 0.001). The correlation coefficient between peak L-[1-(13)C]phenylalanine level and liver weight/body weight was highest, 0.927 (P < 0.001). CONCLUSION: In a breath test with intravenously administered L-[1-(13)C]methionine or L-[1-(13)C]phenylalanine, hepatopathy could be quantitatively evaluated by measuring expiratory (13)CO(2) levels over 15 min. After administration of L-[1-(13)C]phenylalanine, hepatopathy could be quantitatively evaluated in a short period by measuring the peak expiratory (13)CO(2) level.

Animals↗
PubMed1999

Long-term outcome of patients with unexplained syncope treated with an electrophysiologic-guided approach in the implantable cardioverter-defibrillator era.

OBJECTIVES: We evaluated the long-term outcome of patients with coronary artery disease and unexplained syncope who were treated with an electrophysiologic (EP)-guided approach. BACKGROUND: Electrophysiologic studies are frequently performed to evaluate unexplained syncope in patients with coronary artery disease. Patients with this profile who have inducible ventricular tachycardia are considered at high risk for sudden death and increased overall mortality, and therefore are often treated with an implantable cardioverter-defibrillator (ICD). The impact of this EP-guided strategy is unknown because there are no data comparing the long-term outcome of ICD recipients with that of noninducible patients. METHODS: We evaluated 67 consecutive patients with coronary artery disease and unexplained syncope. All patients were treated with an EP-guided approach that included ICD implantation in patients with inducible ventricular tachycardia. RESULTS: Electrophysiologic testing suggested a plausible diagnosis in 32 (48%) of these patients. Inducible monomorphic ventricular tachycardia was the most common abnormality. Despite frequent appropriate therapy with ICDs, the total mortality for patients with inducible monomorphic ventricular tachycardia was significantly higher than for noninducible patients. The respective one- and two-year survival rates were 94% and 84% in noninducible patients and 77% and 45% in inducible patients (p = 0.02). CONCLUSIONS: Electrophysiologic testing suggests an etiology for unexplained syncope in approximately 50% of patients and risk stratifies these patients with regard to long-term outcome. Patients who receive an ICD for the management of inducible ventricular tachycardia have a high incidence of spontaneous ventricular arrhythmias requiring ICD therapy. However, despite ICD implantation and frequent appropriate delivery of ICD therapies, patients with inducible ventricular tachycardia have a significantly worse prognosis than do those who are noninducible.

Aged↗
PubMed1999

Solitary fibrous tumor of the buccal mucosa: report of a case with immunohistochemical studies.

We describe a case of a solitary fibrous tumor of the buccal mucosa and report the results of immunohistochemical studies of the lesion. Solitary fibrous tumors are extremely rare in the intraoral region. These tumors are generally difficult to diagnose because of their broad range of morphologic characteristics. We regard the expression of CD34 within the appropriate clinical and morphologic setting, in the absence of reactivity for other specific markers of differentiation, as evidence supporting the diagnosis of solitary fibrous tumor.

Adult↗
PubMed1999

Radical surgery for Budd-Chiari syndrome. Direct excision and repair for obstruction of the vena cava (Budd-Chiari syndrome) under hepatic vascular exclusion using a centrifugal pump.

OBJECTIVE: To attempt to reduce the incidence of hepatic and cardiac failure after radical surgery for the Budd-Chiari syndrome. DESIGN: Retrospective case study. SETTING: University hospital, Japan SUBJECTS: Three patients with obstruction of the vena cava (Budd-Chiari syndrome) by a thick membrane, thrombus, and a long stenosis, respectively. INTERVENTION: Direct excision and repair by patch dilatation under hepatic vascular exclusion using a Biomedicus centrifugal pump. RESULTS: Hepatic vascular exclusion provides good visibility and enables accurate assessment of the obstruction, proper treatment, and relatively little blood loss. There were no complications, particularly liver failure or heart failure, and the inferior vena cava stayed patent in all cases. Liver function was improved in all three patients. CONCLUSION: This technique is safe and reliable for removal of obstruction of the inferior vena cava (Budd-Chiari syndrome).

Animals↗