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Biomedical subjects

K Komori

Publications and source records attributed to K Komori.

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

Value of the profundapopliteal collateral index for selecting between an in-flow and sequential arterial reconstruction in patients with multisegment arterial occlusive disease.

BACKGROUND: It remains difficult for surgeons to choose between an in-flow and sequential arterial reconstruction in patients with multisegment arterial occlusive disease. In addition, the exact criterion for the proper revascularization procedures of these patients also remains obscure. METHODS: The profundapopliteal collateral index (PPCI) was determined in all patients with occlusions of both the aortoiliac and superficial femoral arteries prior to undergoing an arterial bypass. The PPCI in the inflow bypass (IB) was also compared with the sequential bypass (SB). RESULTS: The symptoms of all patients undergoing either IB or SB improved. Preoperatively, the average PPCI in IB patients was significantly lower than that in SB patients. In addition, no significant difference was observed in the increased average rate of the ankle brachial index (ABI) between IB and SB. CONCLUSIONS: The PPCI is an accurate predictor of the hemodynamic potential of the geniculate collaterals. In cases with a low PPCI, especially in patients with multisegment arterial occlusive disease, in-flow procedures alone may often be sufficient for the successful treatment of such patients. The PPCI is thus considered to be useful for selecting the optimal revascularization procedures.

Aged↗
PubMed2000

[Usefulness of preadmission autologous blood donation and intraoperative autotransfusion using the "cell saver" for the patients with abdominal aortic aneurysm repair].

To evaluate the effectiveness of preadmission autologous blood donation (PABD) and intraoperative autotransfusion (IAT) in reducing the homologous transfusion requirement of abdominal aortic aneurysm (AAA) resection, we retrospectively reviewed 232 AAA cases from January 1991 to December 1999. The patients were separated into three groups. The group I (n = 101) received no PAPD and IAT. The group II (n = 58) received only IAT. The group III (n = 73) received both PAPD and IAT. Surgical data indicating operative time and intraoperative blood loss did not differ among the three groups. However, the incidence of requirement for homologous transfusion in group III (19.2%) is significantly less than those of group I (63.4%) or group II (51.7%), although there was no significant difference between group I and group II. We concluded that the combination of PAPD and IAT are useful for reducing the incidence of requirement for homologous transfusion in the patients with aneurysmal resection.

Aged↗
PubMed2000

Successful resection of superior mesenteric artery aneurysm. A case report and review of the literature.

Superior mesenteric artery aneurysms are rare, comprising only 8% of all visceral artery aneurysms. Aneurysms at the site are very susceptible to rupture, irrespective of size and may be difficult to manage even in the case of elective surgery. In the absence of serious complicating factors, the treatment of choice is excision of the aneurysm and reconstruction of the artery, if necessary, to maintain patency. We report the successful resection of an aneurysm and the subsequent reconstruction of the superior mesenteric artery which was directly anastomosed to the aorta after resection of an aneurysm.

Anastomosis, Surgical↗
PubMed2000

[A case of urinary stone in ureterocele extracted transurethrally after ESWL].

A 66-year-old man was referred to our hospital with chief complaints of difficulty in urination and terminal micturition pain. Ureteroceles were identified bilaterally, and a ureteral stone (19 x 12 mm) existed in the right ureterocele. After crushing the stone by extra corporeal shock wave lithotripsy (ESWL), we removed the stone transurethrally with a small incision in the right ureterocele. The vesicoureteral reflux (VUR) was not detected postoperatively. Now, we recommend the combination of ESWL and a small transurethral incision of the urelerocele for the treatment of ureteral stones in a ureterocele in order to prevent postoperative VUR.

Aged↗
PubMed2000

[Retrieval and cryopreservation of testicular sperm].

We reviewed 44 cases of non-obstructive azoospermia treated by testicular sperm extraction and intracytoplasmic sperm injection (ICSI) from July, 1997 to September 1999 at our institutes. Testicular sperm were retrieved from 32 patients (72.7%). ICSI was performed on 29 patients and the partners of 15 patients (46.9%) became pregnant. Out of 10 patients with histology of Sertoli-cell-only, we could retrieve sperm from 3 patients (30%). Testicular volume, Johnsen's score count (JSC), and FSH were significant parameters to predict the recovery of testicular sperm from the patients, but if only the patients with JSC less than 8, are analyzed, none of them was significant parameter. Chromosomal abnormality was not a significant parameter. The partner's age, motility of recovered sperm and testicular volume correlated with the fertilization rate. Chromosomal abnormality or the usage of cryopreserved sperm was not a significant parameter to predict fertilization.

Adult↗
PubMed2000

[A case of ammonium urate urinary stones with anorexia nervosa].

A 27-year-old woman had been suffering from bulimia and habitual vomiting for about 7 years and was incidentally found to have right renal stones by computed tomography. She was referred to our hospital for the treatment of these caluculi. On admission, she presented with hypokalemia, hypochloremia and metabolic alkalosis and was diagnosed with anorexia nervosa. Following successful removal by percutaneous nephrolithotripsy and extracorporeal shockwave lithotripsy the stones were found to consist of pure ammonium urate. Since the urine of an anorexia nervosa patient tends to be rich in uric acid and ammonium, anorexia nervosa seems to be associated with ammonium urate urinary stones.

Adult↗
PubMed2000

Multivariate analysis of long-term results after an axillobifemoral and aortobifemoral bypass in patients with aortoiliac occlusive disease.

BACKGROUND: Controversy still remains regarding the long-term results and indications for axillofemoral bypass (AxFB). A comparison of axillobifemoral bypass (AxBFB) and aortobifemoral bypass (ABFB) was thus conducted to determine whether AxFB is an acceptable alternative vascular procedure to anatomic bypass for high-risk patients. METHODS: Sixty-three patients who underwent a total of 25 AxBFBs and 38 ABFBs for aortoiliac occlusive disease were reviewed retrospectively, and both univariate and multivarate analyses were perfomed. RESULTS: The overall survival was 82.8% at five years. A univariate analysis revealed significantly lower survival rates for patients with limb-threatening ischemia, coronary disease, and cerebrovascular disease. A multivariate analysis disclosed no significant factors influencing survival rates. The overall primary patency was 79.8% at five years. The primary patency rates for AxBFB (67.7% at five years) were significantly lower than for ABFB (88.5% at five years) based on a univariate analysis (p=0.0045). In addition, the secondary patency rates for AxBFB (80.3% at five years) were significantly lower than for ABFB (96.5% at five years, p=0.0025). A multivariate analysis disclosed significantly lower primary patency rates for grafts with a higher angiographic outflow score and simultaneous infrainguinal reconstructive procedures, but the differences between AxBFB and ABFB were not significant. CONCLUSIONS: The survival and primary patency for the AxBFB group were both inferior to the ABFB group, however a multivarate analysis disclosed no significant differences between the two groups. Poor femoral run-off and the presence of synchronous infrainguinal reconstructive procedures significantly affected graft patency, and these factors modulated the patency of AxBFB. AxFB for aortoiliac occlusive disease is therefore considered to be an acceptable procedure in appropriately selected patients.

Adult↗
PubMed1999

PI-PfuI and PI-PfuII, intein-coded homing endonucleases from Pyrococcus furiosus. I. Purification and identification of the homing-type endonuclease activities.

We screened for proteins with specific binding activity to Holliday junction DNA from the hyperthermophilic archaeon Pyrococcus furiosus and found a protein that has specific affinity for DNA with a branched structure, like a three-way or four-way junction. The protein was identified as one of the two inteins encoded in the gene for ribonucleotide reductase (RNR) by gene cloning. These two inteins were spliced out from the precursor protein as polypeptides with molecular weights of 53.078 and 43.976 kDa, respectively. The amino acid sequences of these inteins have two copies of the LAGLIDADG motif, which is found in the site-specific DNA endonucleases. The purified proteins actually cleaved double-stranded DNA with the sequence of the intein(-)allele, and, therefore, they were designated PI- Pfu I and PI- Pfu II. They generate a 4 bp 3'-OH overhang with a 5'-phosphate, like other known homing endonucleases originating from inteins. The optimal conditions of the DNA cleavage reaction, including temperature, pH, and concentrations of KCl and MgCl(2), have been determined. The high affinity for junction DNA of PI- Pfu I was confirmed using the purified protein.

Amino Acid Motifs↗
PubMed1999

PI-PfuI and PI-PfuII, intein-coded homing endonucleases from Pyrococcus furiosus. II. Characterization Of the binding and cleavage abilities by site-directed mutagenesis.

PI- Pfu I and PI- Pfu II from Pyrococcus furiosus are homing endonucleases, as shown in the accompanying paper. These two endonucleases are produced by protein splicing from the precursor protein including ribonucleotide reductase (RNR). We show here that both enzymes specifically interact with their substrate DNA and distort the DNA strands by 73 degrees and 67 degrees, respectively. They have two copies of the amino acid sequence motif LAGLIDADG, which is present in the majority of homing endonucleases and provides some of the catalytic residues necessary for DNA cleavage activity. Site-specific mutagenesis studies showed that two acidic residues in the motifs, Asp149 and Glu250 in PI- Pfu I, and Asp156 and Asp249 in PI- Pfu II, were critical for catalysis. The third residues of the active site triads, as predicted from the structure of PI- Sce I, were Asn225 in PI- Pfu I and Lys224 in PI- Pfu II. Substitution of Asn225 in PI- Pfu I by Ala did not affect catalysis. The cleavage activity of PI- Pfu II was 50-fold decreased by the substitution of Ala for Lys224. The binding affinity of the mutant protein for the substrate DNA also decreased 6-fold. The Lys in PI- Pfu II may play a direct or indirect role in catalysis of the endonuclease activity.

Amino Acid Motifs↗
PubMed1999

A Holliday junction resolvase from Pyrococcus furiosus: functional similarity to Escherichia coli RuvC provides evidence for conserved mechanism of homologous recombination in Bacteria, Eukarya, and Archaea.

The Holliday junction is an essential intermediate of homologous recombination. RecA of Bacteria, Rad51 of Eukarya, and RadA of Archaea are structural and functional homologs. These proteins play a pivotal role in the formation of Holliday junctions from two homologous DNA duplexes. RuvC is a specific endonuclease that resolves Holliday junctions in Bacteria. A Holliday junction-resolving activity has been found in both yeast and mammalian cells. To examine whether the paradigm of homologous recombination apply to Archaea, we assayed and found the activity to resolve a synthetic Holliday junction in crude extract of Pyrococcus furiosus cells. The gene, hjc (Holliday junction cleavage), encodes a protein composed of 123 amino acids, whose sequence is not similar to that of any proteins with known function. However, all four archaea, whose total genome sequences have been published, have the homologous genes. The purified Hjc protein cleaved the recombination intermediates formed by RecA in vitro. These results support the notion that the formation and resolution of Holliday junction is the common mechanism of homologous recombination in the three domains of life.

Amino Acid Sequence↗
PubMed1999

Properties of endothelium and smooth muscle cells in canine femoral arteries after lumbar sympathectomy.

OBJECTIVE: To find out whether the lumbar sympathectomy modulated the endothelial function (as measured by nitric oxide (NO) and prostacyclin (PGI2), and blood flow in the canine femoral artery. DESIGN: Laboratory experiments. SETTING: Teaching hospital, Japan. ANIMALS: 16 mongrel dogs. INTERVENTION: Unilateral sympathectomy from L3 to L6. MAIN OUTCOME MEASURES: Five weeks later, the changes in blood flow, the endothelium-dependent responses and the PGI2 production in the canine femoral arteries were measured. RESULTS: The median (range) blood flow of left (denervated) and right (innervated) femoral arteries was 162 ml/min (122-330) and 65 ml/min (40-92), respectively. There was a significant difference between the two groups (p < 0.01). The endothelium-dependent relaxations to acetylcholine, adenosine diphosphate (ADP) and A23187 were comparable. The amounts of PGI2 produced in the two groups were similar. Direct relaxation in response to sodium nitroprusside was also similar in the two groups. CONCLUSIONS: Lumbar sympathectomy did not alter the endothelial function, although the median blood flow in the denervated femoral arteries was significantly higher than in the innervated ones. The continuous vasodilatation after sympathectomy may be a more potent factor in the regulation of vascular tonus than the physiological regulation of NO and PGI2.

Animals↗
PubMed1999

In situ localization of S-phase-specific histone (H3) mRNA in Bowen's disease.

PCNA and Ki-67 immunohistochemistry has been used to assess cell proliferation in place of tritiated thymidine or BrdU labeling of S-phase cells. Recently, it has been possible to reliably demonstrate histone H3 mRNA by in situ hybridization in formalin-fixed and paraffin-embedded tissue sections. We have compared this new proliferation marker with Ki-67 and PCNA with regard to distribution of positive cells and labeling indices (LI%) for 22 cases of Bowen's disease. In normal skin, Ki-67-IHC positive cells and histone mRNA positive cells were observed in the basal and suprabasal layers of the epidermis. In Bowen's disease, positive cells with each marker were more frequent in upper neoplastic epidermis than in suprabasal layers, and the average LI%s were markedly elevated with all markers, the scores decreasing in the following order: PCNA-IHC, Ki-67-IHC and H3mRNA-ISH. However, the results of double staining demonstrated that S-phase cells do not necessarily show exactly the same distributions as with PCNA and Ki-67-IHC labeling. H3mRNA-ISH showed three different degrees of reaction with significantly different LI%s, whereas PCNA and Ki-67 LI% did not vary essentially in the same areas. These results strongly suggest that Bowen's disease, which is well known as a low-grade neoplastic state with malignant potential, also demonstrates clear intratumoral heterogeneity of S-phase cells using the H3mRNA-ISH method.

Adult↗
PubMed1999

Functional interactions of a homolog of proliferating cell nuclear antigen with DNA polymerases in Archaea.

Proliferating cell nuclear antigen (PCNA) is an essential component of the DNA replication and repair machinery in the domain Eucarya. We cloned the gene encoding a PCNA homolog (PfuPCNA) from an euryarchaeote, Pyrococcus furiosus, expressed it in Escherichia coli, and characterized the biochemical properties of the gene product. The protein PfuPCNA stimulated the in vitro primer extension abilities of polymerase (Pol) I and Pol II, which are the two DNA polymerases identified in this organism to date. An immunological experiment showed that PfuPCNA interacts with both Pol I and Pol II. Pol I is a single polypeptide with a sequence similar to that of family B (alpha-like) DNA polymerases, while Pol II is a heterodimer. PfuPCNA interacted with DP2, the catalytic subunit of the heterodimeric complex. These results strongly support the idea that the PCNA homolog works as a sliding clamp of DNA polymerases in P. furiosus, and the basic mechanism for the processive DNA synthesis is conserved in the domains Bacteria, Eucarya, and Archaea. The stimulatory effect of PfuPCNA on the DNA synthesis was observed by using a circular DNA template without the clamp loader (replication factor C [RFC]) in both Pol I and Pol II reactions in contrast to the case of eukaryotic organisms, which are known to require the RFC to open the ring structure of PCNA prior to loading onto a circular DNA. Because RFC homologs have been found in the archaeal genomes, they may permit more efficient stimulation of DNA synthesis by archaeal DNA polymerases in the presence of PCNA. This is the first stage in elucidating the archaeal DNA replication mechanism.

Amino Acid Sequence↗
PubMed1999

Increased prostacyclin production after percutaneous transluminal angioplasty of the iliac artery for atherosclerosis obliterans.

BACKGROUND: Endothelial prostacyclin production is modulated by blood flow (wall shear stress). Local plasma prostacyclin concentrations and hemodynamic parameters have therefore been investigated in patients with atherosclerosis obliterans before and after angioplasty. METHODS. DESIGN: Prospective study. SETTING: Department of Surgery, Matsuyama Red Cross Hospital, Matsuyama, Japan. PATIENTS: Nine lower limbs in eight patients with significant stenoses of the iliac artery were studied. INTERVENTIONS: blood samples were obtained from the femoral artery and femoral vein of nine lower limbs undergoing percutaneous balloon angioplasty of the iliac artery. MEASURES: Prostacyclin concentrations, radioimmunoassayed as 6-keto-prostaglandin F1 alpha, were measured before and after balloon dilatation. Femoral blood flow and the ankle-brachial pressure index (ABI) were measured using a Doppler velocimeter before and after the procedure. The femoral blood flow waveform was used to calculate the mean blood flow and shear stress variation. RESULTS: Before angioplasty, the mean (+/- SEM) plasma prostacyclin concentration was 21.6 +/- 1.5 pg/ml in the femoral artery and 25.4 +/- 1.1 pg/ml in the femoral vein. After angioplasty, these values increased to 25.6 +/- 2.2 pg/ml (p < 0.05) and 32.8 +/- 1.8 pg/ml (p < 0.01), respectively. The pre-procedural ABI, mean flow rate, and shear stress variation were 0.596 +/- 0.071, 354.1 +/- 63.3 ml/min, and 69.1 +/- 9.9 dyne/cm2, respectively. Both ABI and shear stress variation increased after angioplasty to 0.738 +/- 0.076 (p < 0.05) and 111.1 +/- 24.2 (p = 0.0775) dyne/cm2, but the mean flow rate (287.1 +/- 61.1 ml/min after angioplasty) did not increase (p = 0.2002). CONCLUSIONS: These results suggest that prostacyclin production increases after angioplasty, possibly due to increases in the intraluminal pressure and shear stress variation. This enhanced prostacyclin production may help to maintain arterial or bypass graft patency.

Aged↗