Biomedical subjects

T Ohta

Publications and source records attributed to T Ohta.

At least 775 records · Page 43Linked to original sources

PubMed1994

Neural invasion and nodal involvement in distal bile duct cancer.

Nodal status and neural plexus invasion are important prognostic factors in pancreaticobiliary cancer. The relationship between neural invasion and nodal involvement is evaluated, and its significance for therapy discussed. During the last 20 years, 29 patients with distal bile duct cancer underwent pancreaticoduodenectomy at our institute. An accurate evaluation of the relationship between nodal involvement and plexus invasion was done by histological examination. Twenty of the 29 patients had nodal involvement (68.9%) including 11 patients (37.9%) with nodal involvement of the third group of lymph node (n3). None of these 11 patients had tumors confined to the bile duct wall (panc0 disease). Eight patients (27.6%) had plexus invasion. None of these patients had panc0 disease. The most frequent site of extrapancreatic plexus invasion was the first portion of the plexus pancreaticus capitalis. Nodal dissection around the superior mesenteric artery, and plexus dissection in the hepatoduodenal ligament, around the hepatic artery, and at the first portion of plexus pancreaticus capitalis is necessary in the treatment of distal bile duct cancer, except in patients with no evidence of pancreatic invasion.

Adult↗

PubMed1994

Recurrence of cystic adventitial disease in an interposed vein graft.

A case of cystic adventitial disease (CAD) of the popliteal artery with intermittent claudication in the left calf is reported. This patient was first treated by total excision of the cyst and the involved artery followed by graft interposition with an autogenous saphenous vein. Recurrence of CAD in the interposed vein graft was noted after 6 months, and excision of the cyst with the involved graft and graft interposition with an autogenous saphenous vein was again required. We consider that the definitive evidence from early recurrence in the interposed vein graft shown in this case will close the discussion of the cause of CAD. The cystic lesion is thought by some to originate from the adventitia; traumatic, embryologic, or systemic abnormality theories were proposed. We assume that the mucin-secreting synovial cells originating from the neighboring joint capsule, tendon sheath, or, in some cases, from the ganglion itself, directly invade the adventitia through any rough or injured crack caused by trauma to the adventitia or simply attach to and encircle the adventitia. Total resection of the lesion with grafting is the recommended treatment for CAD because of the excellent results. However, as shown in our case, complete removal of the synovial cells even by resection technique may be difficult; therefore intensive follow-up is fundamentally necessary in this disease.

Adult↗

PubMed1994

[A case of drug induced pneumonitis caused by saiboku-To].

We report a case of drug induced pneumonitis caused by Saiboku-To. A 60-year-old woman was admitted to our hospital because of dry cough, fever and severe dyspnea after taking Saiboku-To. Blood gas analysis showed marked hypoxemia. Chest X-ray obtained on admission showed diffuse ground glass shadows in bilateral lung fields, and computed tomography showed diffuse interstitial shadows. Following steroid pulse therapy, clinical symptoms, hypoxemia and chest X-ray findings were ameliorated. Against medical advice, she took another Chinese medicine with ingredients similar to those of Saiboku-To. She complained of dry cough, fever and dyspnea and the chest X-ray again revealed diffuse ground glass shadows in both lung fields. Lymphocyte stimulation test against Saiboku-To and the patch test for Saiboku-To were positive. Therefore, we diagnosed this case as having pneumonitis due to Saiboku-To. This is first report of interstitial pneumonitis due to Saiboku-To.

Alveolitis, Extrinsic Allergic↗

PubMed1994

[Progress of preoperative diagnosis of pancreatic tumor--with special reference to extension of pancreatic cancer].

Preoperative diagnosis of the extension of pancreatic cancer is very important for determining the range of resection. We evaluated the preoperative imaging diagnosis of the tumors and compared it with the pathological diagnosis. Out of 68 pancreatic head cancers, the percentage of correct diagnosis of serosal invasion was 69.1%, that of over-estimate was 23.5% and that of under-estimate was 7.4%. In the case of retroperitoneal invasion, a correct diagnosis had been made in 79.1%, over-estimate in 4.5% and under-estimate in 16.4%. In the case of portal vein invasion, these percentages were 52.8%, 39.6% and 7.5%, respectively. In the case of lymph node involvement, these percentages were 85.3%, 2.9% and 11.8%, respectively. The percentage of preoperative over-estimate was higher for serosal invasion and that of preoperative under-estimate was higher for retroperitoneal invasion. In the case of portal vein invasion, the percentage of preoperative over-estimate was relatively high. Of the 12 patients who had paraortic lymph node metastases, 6 patients had a single metastatic node in the paraortic area. The minimum size of these nodes was 2 x 2 mm. Only 5 cases could be diagnosed preoperatively. We evaluated the usefulness of abdominal CT scan and superior mesenteric arteriography for the diagnosis of superior mesenteric arterial wall invasion. In both methods, the over-estimate rate was 0%, but the under-estimate rate was relatively high. Conclusively the preoperative diagnosis of the extension of the pancreatic cancer by conventional imaging methods has some limits.

Humans↗

PubMed1994

[Permanent pacemaker lead insertion for totally occluded subclavian vein].

We experienced 4 patients with total occlusion of the subclavian vein in whom permanent pacemakers were implanted. Occlusion of the subclavian vein was not clinically apparent in these 4 patients. The pacing lead was inserted through the contralateral subclavian vein in a 65-year-old male. In a 80-year-old male, the pacing lead was inserted trough the internal jugular vein because of occlusion of both subclavian veins. The pacing lead was passed through the occluded portion of the innominate vein in a 84-year-old male. Phlebography-guided venipuncture was not difficult in a 79-year-old female whose mid-portion of the subclavian vein was occluded. All patients have done well since permanent pacemaker implantation. Preoperative phlebography should be performed as it may provide useful information concerning pathological alterations in the venous system that might hinder smooth implantation of the pacemaker. A review of the literature revealed no reports concerning methods in which pacing leads are passed through totally occluded portions of the subclavian vein. We here report 4 patients with total occlusion of the subclavian vein in whom permanent pacemakers were implanted via different venous routes.

Adult↗

PubMed1994

[A case of acute aortic dissection with aortic regurgitation successfully treated by postoperative ECMO].

A case of acute aortic dissection (Stanford Type A) with severe aortic regurgitation successfully treated by postoperative ECMO was reported. The patient was 41-year-old man in shock condition and was transferred to Kobe University Hospital. Chest CT scan and echocardiogram revealed acute aortic dissection with severe aortic regurgitation. An emergent operation by Collins' method and resuspension of aortic valve were carefully performed. Consequent ECMO was necessitated because of postoperative left ventricular and respiratory failure. Thereby, ECMO using heparin-coated CBAS-MAXIMA membrane oxygenator, centrifugal pump, and tubes was established by arterial cannulation via the anastomotic site of the ascending aorta to prevent the obstruction of the aortic true lumen by the false lumen which may be enlarged by retrograde perfusion via the femoral artery. Left ventricular function and pulmonary function were improved after 6 hours and 20 minutes, thus ECMO was successfully weaned without any complications.

Adult↗

PubMed1994

A new tumor promotion pathway and its inhibitors.

Tumor promotion is a critical point in multistage carcinogenesis in humans. We have identified a common biochemical and molecular tumor promotion mechanism, the okadaic acid pathway, applicable in various organs. Tumor promotion by the okadaic acid class of compounds is mediated through inhibition of protein phosphatases 1 and 2A, resulting in an increase of protein phosphorylation and a subsequent expression of cell proliferation genes. Recently, we demonstrated that okadaic acid induced the release of mouse tumor necrosis factor-alpha (mTNF-alpha) from BALB/3T3 cells. The first part of this review discusses the link between the okadaic acid pathway and TNF-alpha as endogenous tumor promoters in vivo. Inhibitors of tumor promotion are varied. For the purpose of cancer chemoprevention in humans, the inhibitors sarcophytol A, canventol, and (-)-epigallocatechin gallate (EGCG) were studied and the results are presented. The inhibitory mechanisms also were varied: sarcophytol A inhibited H2O2 formation by TPA-activated human polymorphonuclear leukocytes; canventol inhibited protein isoprenylation in the cells; and EGCG, which is a main constituent of Japanese green tea, is an antioxidant. These inhibitors are promising cancer chemopreventive agents. Study of the essential tumor promotion mechanisms will facilitate the development of cancer chemopreventive agents.

Anticarcinogenic Agents↗

PubMed1994

[Extramedullary blastic crisis of chronic myelogenous leukemia--a case with various additional chromosomal appearance].

We describe a characteristic case of chromosomal abnormalities in a 47-year-old man with chronic myelogenous leukemia (CML). He had been diagnosed with the chronic phase of CML on May 1990, but he refused treatment. He was readmitted in October 1991 because of peripheral lymphadenopathy. Hematologic studies showed that he remained in the chronic phase of CML. There were no additional chromosomal findings in the bone marrow, but cervical lymph node biopsy revealed complete replacement with blastoid cells. The blasts were positive for CD13 and CD33. DNA analysis for the breakpoint cluster region gene showed rearrangement pattern, but immunoglobulin heavy chain joining region genes and T-cell antigen receptor gene rearrangement were not observed. The karyotype of lymph node cells showed various additional chromosomal abnormalities. Therefore, we concluded that the patient had an extramedullary blastic crisis in his peripheral lymph nodes. Abnormal clones were composed of one main clone and three subclones, with the latter occupying more than 10% of the volume each other. Considering the types of the additional chromosomal abnormalities, all four types of clones were thought to have evolved through independent pathways.

Blast Crisis↗

PubMed1994

[EC-IC bypass surgery using saphenous vein graft: technical improvement in our experience].

We managed ten cases of EC-IC bypass using a vein graft; six cases with multiple cerebral arterial occlusion and four cases with aneurysm necessitating therapeutic occlusion of the parent artery (Table). Patency of the graft was confirmed in seven cases on long-term follow-up ranging from 7 months to 5 years. Of the ten cases, two died within 7 days after surgery from causes unrelated to the bypass and one was lost in follow-up surgery. Hemorrhagic infarction was observed in two cases, one of which underwent removal of the hematoma. In five cases with cerebral occlusive disease, there were no additional ischemic events and two cases with giant aneurysms showed improvement of visual acuity and extraocular movement. We improved on several surgical techniques for vein graft. We used small hemoclips to occlude branches of the saphenous vein instead of ligating them, which shortens the harvesting time of the saphenous vein. Vessel cannula with a small-sized elegant tip and one-directional valve (DLP, INC., USA) was also used to inflate or deflate vein grafts with saline. It was easily attached to the graft and minimized air entrapment in the lumen. Small clips for microvascular anastomosis (Mizuho INC., Japan) were used to temporarily occlude branches or perforators from the recipient artery. One of the branches of the graft was dissected long enough, through which intraluminal air or thrombus was washed out at the final stage of the surgery. These procedures are useful for shortening occlusion time of the recipient artery and decreasing the risk of embolism.

Adult↗

PubMed1993

Elevation of serum albumin by intrahepatic transplantation of albumin-producing cells does not correct quantitative abnormalities of non-albumin proteins in analbuminemic rats.

Nagase analbuminemic rats (NAR) show quantitative abnormalities of non-albumin serum proteins which could represent a compensatory response to the analbuminemia, although total serum protein levels are normal. When hyperplastic hepatic nodule (HPN) cells of F344 rats, which produce albumin, were infused into the portal vein of congenic analbuminemic rats (F344-alb) followed by treatment with the Solt and Farber dietary regimen, the transplanted cells grew within the livers, occasionally developing into hepatocellular carcinomas (HCC). In the recipient F344-alb, while serum albumin was considerably elevated, the total serum protein was also increased. Moreover, the abnormal pattern of serum proteins in NAR was unchanged by the elevation of albumin. These results indicate that the unique pattern of serum proteins in NAR is constitutive and cannot be corrected by a continuous increase in albumin levels.

Animals↗

PubMed1993

An examination of the generation-time effect on molecular evolution.

By using DNA sequences of 17 mammalian genes, the generation-time effect is estimated separately for synonymous substitutions and nonsynonymous substitutions. Star phylogenies composed of rodentia, artiodactyla, and primates are examined. The generation-time effect is found to be more conspicuous for synonymous substitutions than for non-synonymous substitutions, by using the methods of (i) Nei and Gojobori, (ii) Li, and (iii) Ina. The proportion of accepted amino acid substitutions in evolution is estimated to be about twice as large in the primate lineage as in the rodent lineage. This result is in accord with the nearly neutral theory of molecular evolution.

Animals↗

PubMed1993

Lymphatic flow in carcinoma of the distal bile duct based on a clinicopathologic study.

BACKGROUND: Nodal status is one of the most important prognostic factors for distal bile duct cancer. The pattern of lymphatic spread of distal bile duct cancer was analyzed by determining the frequency of involvement of various lymph nodes. MATERIALS AND METHODS: From 1973 to 1991, 29 patients with distal bile duct cancer underwent pancreaticoduodenectomy at Kanazawa University Hospital. A precise evaluation of their nodal involvement and the relationship among the lymph nodes was determined by histopathologic examination. RESULTS: Twenty of the 29 (68.9%) patients had nodal involvement. The lymph nodes with a high metastatic rate were those around the lower portion of the hepatoduodenal ligament (number 12abp2), the superior posterior pancreaticoduodenal lymph nodes (number 13a), and the superior mesenteric artery (number 14) (12abp2, 24.1%; 13a, 51.7%; 14, 34.5%). At least one para-aortic lymph node was involved with cancer in two (6.9%) patients. All of the patients except one who had one or more positive number 14 lymph nodes also had positive number 12abp2 or 13a lymph nodes. CONCLUSIONS: Lymph nodes number 12abp2 and 13a are important in lymphatic metastasis to superior mesenteric lymph node for distal bile duct cancer. Nodal dissection around the superior mesenteric artery should be performed in all patients except those without pancreatic invasion.

Adult↗

PubMed1993

An evaluation of radical resection for pancreatic cancer based on the mode of recurrence as determined by autopsy and diagnostic imaging.

BACKGROUND: To determine the extent of dissection in curative resection for cancer of the pancreatic head, the mode of recurrence was determined at autopsy and by radiographic examinations. MATERIALS AND METHODS: Records of 45 patients who had undergone macroscopically curative resection of carcinoma of the head of pancreas were analyzed to determined the mode of recurrence. The mode of recurrence was divided into four types: hepatic metastasis, peritoneal dissemination, retroperitoneal recurrence, and distant metastasis. Retroperitoneal recurrence was subdivided into lymph node metastasis and local recurrence, primarily neural invasion and lymphatic invasion. RESULTS: Thirty patients experienced disease recurrence. Patients with Stage I or II disease experienced recurrence significantly less often than did patients with Stage III or IV disease (P < 0.05). Local retroperitoneal recurrence was discovered in 12 of 15 (80%) postmortem examinations, hepatic metastasis in 10 (66%), peritoneal dissemination in 8 (53%), and lymph node recurrence in 7 (47%). In 15 antemortem studies, retroperitoneal recurrence occurred most frequently (87%), followed by hepatic metastasis (53%). Almost all patients with liver metastasis also had local retroperitoneal recurrence. CONCLUSIONS: The frequency of retroperitoneal recurrence of carcinoma of the head of the pancreas suggests that retroperitoneal resection, including nerve plexi and lymph nodes, should be included in curative resections for patients with Stage I or II pancreatic cancer.

Adenocarcinoma↗

PubMed1993

Histidine 296 is essential for the catalysis in Lactobacillus plantarum D-lactate dehydrogenase.

Two His residues, His-205 and His-296, in Lactobacillus plantarum D-lactate dehydrogenase are highly conserved in the D-isomer-specific 2-hydroxyacid dehydrogenase family, suggesting that they are candidates for the catalytic His in the enzyme. The substitution of His-296 with Tyr by means of site-directed mutagenesis induced a drastic decrease in the reaction rate, while a His-205 to Tyr substitution induced no large change in the catalytic properties. In pyruvate reduction, the Tyr-296 enzyme showed a slightly increased Km below pH 6.0 but no significant pH dependence above pH 6.0, where the wild-type enzyme showed an increased Km value. In D-lactate oxidation, in contrast, the Tyr-296 enzyme showed a greatly increased Km value for D-lactate and strong pH dependence. An additional substitution of His-296 with Gln induced more complete loss of the catalytic activity. In contrast to the Tyr-296 enzyme, the Gln-296 enzyme showed a greatly increased Km value and a strong pH-dependent reaction rate even in pyruvate reduction. Unlike the wild-type or His-205 enzyme, both the Tyr-296 and Gln-296 enzymes showed significant resistance against diethyl pyrocarbonate. These results clearly indicate that His-296 is essential for the catalysis by D-lactate dehydrogenase, as in the case of His-195 in L-lactate dehydrogenase.

Amino Acid Sequence↗

PubMed1993

Increase in albumin mRNA by repeated intrahepatic transplantation of F344 rat hepatocytes into the liver of congenic analbuminemic rats.

Hepatocytes of F344 rat were transplanted into the liver of congenic analbuminemic rats by infusion into the mesenteric vein from once to four times at one-week intervals. The transplantability was confirmed by the increase in the number of albumin-positive cells and appearance of normal albumin mRNA within the recipient liver, and the elevated serum albumin level. When the normal albumin mRNA was quantitated by reverse transcriptase polymerase chain reaction (RT-PCR) using the abnormally spliced albumin mRNA of analbuminemic rats as an internal standard, the increase in normal mRNA was in good agreement with the serum albumin level and the number of albumin positive hepatocytes within the liver. These three markers proportionally increased with the number of infusion times. Our results demonstrate that the number of intrahepatically transplanted hepatocytes is able to be increased by repeated infusion.

Animals↗

PubMed1993

Molecular characterization of the gene operon of heat shock proteins HSP60 and HSP10 in methicillin-resistant Staphylococcus aureus.

Methicillin-resistance of S.aureus (MRSA) was diminished or depressed at 44 degrees C. In order to investigate whether bacterial heat shock response is correlated with methicillin resistance, we examined the inducibility of the heat shock proteins (HSPs) in MRSA, and cloned and sequenced of their genes. A temperature shift from 37 degrees C to 46 degrees C enhanced the production of at least 8 kinds of cytoplasmic proteins as measured with two-dimensional PAGE. The induced protein profile was almost the same as methicillin sensitive S.aureus, and stress conditions due to ethanol, cadmium or low pH. Two of these proteins were HSP60 and HSP10. Their N-terminal amino acid sequences were 79%, and 83%, homologous with thermobacterium PS3, respectively. A positively hybridized 4.2 kbp DNA fragment encoding both proteins was isolated from the chromosomal DNA of MRSA. The resulting sequence revealed two reading frames and showed high homology to those of hsp60 (groEL) and hsp10 (groES) of bacteria (E.coli) and several other species. The genes of HSP60 and HSP10 in S.aureus comprised an operon as in E.coli. The relationship between those HSPs and PBP2' is currently under investigation.

Amino Acid Sequence↗

PubMed1993

Characterization of the membrane sensor PenJ for beta-lactam antibiotics from Bacillus licheniformis by amino acid substitution.

The PenJ protein of the penicillinase gene (penP) expression system from Bacillus licheniformis is an antirepressor and membrane receptor for beta-lactam antibiotics. A putative beta-lactam antibiotic binding site including Ser402 and Lys405, which are homologous to the conserved sequence for the beta-lactam binding site (Ser-X-X-Lys) is present. An amino acid substitution was introduced at Ser402 to Ala, removing the hydroxyl group of the serine. The mutant PenJ, S402A, was still functional. However, two other mutants, S402T (Ser402-->Thr) and K405A (Lys405-->Ala), were not functional. Thus, the hydroxyl group of Ser402 does not appear to be important for penicillin binding. Amino acid substitutions (K539R, D591N and K539R.G541V) were introduced in PenJ in the region of the putative phosphoryl binding domain. None of these mutant PenJ proteins was a functional antirepressor. These results suggested that the putative phosphoryl binding domain might be an important region for signal transduction.

Amino Acid Sequence↗

PubMed1993

Analysis of the self-defense gene (fmrO) of a fortimicin A (astromicin) producer, Micromonospora olivasterospora: comparison with other aminoglycoside-resistance-encoding genes.

The nucleotide (nt) sequence of a 3409-bp PvuII fragment carrying the self-defense gene (fmrO) of a fortimicin A (FmA; astromicin) producer, Micromonospora olivasterospora, was determined; four open reading frames (ORFs) exist in this region. Expression analysis of fmrO using the lac promoter in Escherichia coli revealed that ORF-3 encodes fmrO. ORF-1 was considered to encode a FmKH epimerase (fms11). ORF-2, ORF-3 and ORF-4 seemed to form an operon. No homology was detected between fmrO and the resistance-encoding gene fmrT of Streptomyces tenjimariensis, a producer of the Fm-group antibiotic, istamycin. Gene organization around the fmr genes differed considerably between M. olivasterospora and S. tenjimariensis. The deduced amino acid sequence of fmrO showed an identity of 30.8% to grmA of M. purpurea and 35.8% to grmB of M. rosea, respectively, suggesting that fmrO encodes a 16S rRNA methyltransferase. We found in M. purpurea a novel resistance gene distinct from grmA and highly similar to fmrO which conferred a resistance phenotype similar to that of fmrO. These results suggest that fmrO of M. olivasterospora and the two resistance-encoding genes of M. purpurea were derived from a common ancestral gene.

Amino Acid Sequence↗