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Biomedical subjects

S Ohki

Publications and source records attributed to S Ohki.

At least 19 recordsLinked to original sources
PubMed1999

Importance of positive peritoneal lavage cytology findings in the stage grouping of gastric cancer.

Although peritoneal lavage cytology is widely performed during surgery for gastric cancer and the results have been reported to be one of the accurate prognostic factors, the cancer stage is determined independent of the results of lavage cytology according to the First English Edition of Japanese Classification of Gastric Carcinoma. In this study we demonstrated the validity of lavage cytology for accurately staging gastric cancer. Between 1988 and 1996, peritoneal lavage cytology was performed in 347 patients with resectable gastric cancer. Among them, cytology was positive in 29 cases (8.4%). The survival rate of the cytology-positive patients in each stage was worse than that of all patients in the same stage. The prognosis of patients with positive cytology findings and serosa-exposed gastric cancer was significantly worse than that of negative cytology findings and serosa-exposed gastric cancer, and similar to that of negative cytology findings and serosa-infiltrating gastric cancer. Our data indicated that positive cytology findings thus indicated a poor prognosis, and the prognostic difference between positive and negative cytology findings was approximately a one-stage difference in the Japanese stage grouping. Based on our findings, the results of peritoneal lavage cytology should thus be included in the factors for staging gastric cancer.

Ascitic Fluid↗
PubMed1999

[Transnasal microsurgery using a micro-pressure-suction-irrigation system for pituitary adenomas].

Micro-pressure-suction-irrigation system (MPSIS), introduced by Luedecke et al, is an instrumentation for the direct transnasal pituitary procedure. We improved this system for use in Japan. The irrigation system can effectively clean the operating field by one-hand manipulation and dissect tumor tissue by its rapid flow. The pressure of suction and irrigation can be adjusted respectively by a device in the handpiece. The MPSIS is applicable to different stages of intervention because it is equipped with separate tips of various diameters, lengths and angles. This system is especially useful in combination with a micromirror or an endoscopy for direct inspection of the eccentric tumor sites such as the cavernous sinus, the upper part of the planum sphenoidale, or the posterior suprasellar regions. The use of the MPSIS helps to avoid injury to normal tissue structures, and prevents tiny soft microadenoma from being lost during preparation. We have proved the suitability and usefulness of the MPSIS in 23 surgical interventions for transnasal microsurgery of pituitary adenomas.

Adenoma↗
PubMed1998

Probe transfer with and without membrane fusion in a fluorescence fusion assay.

An analysis of the R18 fusion assay was made during the fusion of the Sendai virus with erythrocyte ghosts. The increase in R18 fluorescence, reflecting the interaction process, was evaluated in terms of the different processes that in principle may contribute to this increase, that is, monomeric probe transfer, hemifusion, and complete fusion. To this end, the kinetics of the R18-labeled lipid mixing were compared to those obtained with an assay in which the fusion-monitoring probe, eosin-maleimide, was attached to the viral surface proteins. The experiments relied on the use of native and fusion-inactive viruses and studies involving viral and target membranes that were modified by the incorporation of the lysophospholipid. The total dequenching signal detected in the R18 assay consists of components from probe transferred without fusion and from fusion itself. At 37 degrees C, the initial rate of dequenching (within two minutes) was predominately from the probe diluted by fusion with little contribution from transfer. The dequenching signal due to the probe transfer without fusion occurred at temperatures as low as 10 degrees C and increased linearly with time. Complete fusion started at about 20-25 degrees C and increased sharply at 30 degrees C. The extent of hemifusion was deduced from the total R18 dequenching data and those of the eosin-maleimide labeled protein dilution method for the limiting cases; the analysis indicates that hemifusion started at about 15 degrees C and increased over the range 20-25 degrees C. The initial rate of dequenching of the R18 assay measured within 2 min gives an accurate measure of membrane fusion above 30 degrees C.

Eosine Yellowish-(YS)↗
PubMed1998

Inhibitory effects of prostaglandin D2 against the proliferation of human colon cancer cell lines and hepatic metastasis from colorectal cancer.

The inhibitory action of prostaglandin D2 (PGD2) and its effect on the cell cycle were examined in cell lines SW480 and LS174T of human colon cancer. The growth of the cell lines were assessed 24 h and 48 h after the addition of 1.0 microgram/ml and 10.0 micrograms/ml PGD2. The growth of SW480 cells was inhibited 48 h, but not 24 h, after the addition of 1.0 microgram/ml, and 24 h and 48 h after the addition of 10.0 micrograms/ml, while that of LS174T was inhibited by both doses after 24 h and 48 h. S-Phase DNA synthesis in the SW480 cells was significantly blocked 24 h after the addition of 10.0 micrograms/ml PGD2. The cell cycle of LS174T cells was arrested at the G0 + G1 phase 24 h after the addition of 1.0 microgram/ml and 10.0 micrograms/ml PGD2. The correlation between hepatic metastasis and PGD2 concentration in human cancer tissue was examined. The mean value of PGD2 concentrations in the primary cancer tissue was significantly lower in the hepatic metastasis group than that in the group without hepatic metastasis. These findings suggest that measuring the PGD2 in cancer tissue may be useful for detecting and predicting the hepatic metastasis from human colorectal cancer.

Biomarkers, Tumor↗
PubMed1998

Successful graft replacement of the descending aorta after an extended reconstruction of the ascending and transverse aorta in a patient with Marfan's syndrome.

A 27-year-old man with Marfan's syndrome underwent a total aortic graft replacement in three separate stages. Initially the abdominal aorta was replaced, followed by the ascending aorta and aortic arch, and finally the residual portion. The extensive reconstruction of both the ascending and transverse aorta at the second operation, even though no dissection was present in the aortic arch, reduced the risk of the subsequent operation since the same surgical approach did not have to be used.

Adult↗
PubMed1998

Effects of anionic and nonionic polymers on fusion and binding of Sendai virus to human erythrocyte ghosts.

Effects of various polymers (dextran sulfate, dextran and polyethylene glycol) on binding and fusion of Sendai virus to target cells were studied by use of fluorescence spectroscopy. Direct binding of dextran sulfate but not dextran to Sendai virus was detected. Anionic and nonionic polymers showed definite effects on segmental motions of the viral envelope proteins. Sendai virus binding to human erythrocyte ghost membranes (HEG) was reduced by dextran sulfate and dextran while the fusion temperature dependence remained unaltered at approximately 20 degrees C. Nonionic polymer, polyethylene glycol, caused an increase in extent of fusion of Sendai virus with HEG. Segmental motion of viral envelope proteins, determined in terms of anisotropy of fluorescent probes attached to viral surface proteins, exhibited a temperature dependent transition at 20 degrees C by a sharp change from restricted to less restricted motion. In the presence of each of the polymers, this transition was no longer apparent. Since fusion did occur in the presence of all polymers, the temperature dependent characteristic of Sendai virus target cell fusion can be said not to depend on viral surface protein segmental motion. A reasonable and coherent explanation was given for the apparent disparity between the effects of inhibiting and enhancing polymers on fusion and motion of viral proteins.

Animals↗
PubMed1998

Solution structure of a protein inhibitor of neuronal nitric oxide synthase.

The structure of the neuronal nitric oxide synthase inhibitory protein, PIN (protein inhibitor of nNOS), has been determined by NMR spectroscopy. Two N-terminal antiparallel alpha-helices pack against a four-stranded antiparallel beta-sheet in the C-terminal region of the protein, forming a two-layer alpha/beta plait. The three dimensional structure of PIN resembles the fold of the B-chain of aspartylglucosaminidase. A non-prolyl cis peptide bond was found between Pro 52 and Thr 53 of the protein. PIN has a large solvent-exposed hydrophobic surface that contains a cavity and is rimmed with positive charges. This surface may serve as the primary target-binding region for this multi-functional regulatory protein.

Amino Acid Sequence↗
PubMed1998

Anisakidosis: a cause of intestinal obstruction from eating sushi.

We report a case of strangulating small bowel obstruction in a 60-yr-old Japanese woman caused by anisakidosis (previously known as anisakiasis). With the increasing popularity of Japanese cuisine such as sushi in the United States, the incidence of anisakidosis is expected to increase. Intestinal anisakidosis can now be treated temporarily, but this condition may cause a serious obstruction afterwards, as evidenced by this particular case. Over 13,500 cases were reviewed in both the Japanese and English literature, and we discuss the prevention of anisakidosis without negatively altering the taste of the raw fish.

Animals↗
PubMed1998

Management of postoperative fever in cardiovascular surgery.

BACKGROUND: The causes and management of postoperative fever were studied. MATERIALS AND METHODS: During a four-year-period beginning in January of 1991, high fever over 38.5 degrees C max occurred in twenty-five (6%) out of 395 patients who underwent cardiovascular surgery. RESULTS: Nine of the patients (28%) evidenced bacteriological infections as follows; 3 cases of mediastinitis, 2 cases of respiratory tract infection, 1 case of MRSA colitis and a wound infection in one case. The three patients with mediastinitis died and the two cases of MRSA were detected from the culture of pacemaker leads. Bacteriological infection was not detected in other 18 (72%) patients with fever. However, we speculated that the clinical causes of fever in 9 out of 18 patients were as follows; catheter fever in 3 patients, acalculous cholecystitis in 2, fungus infection in 2, aseptic meningitis in one and viral myelitis in one patient. Two patients with acalculous cholecystitis recovered after percutaneous transhepatic gallbladder drainage. The causes of fever were not apparent in nine patients, however the source might be related to artificial prostheses used intraoperatively in five patients. C-reactive protein (CRP) was elevated beyond 10 mg/dl in 13 (52%) of the 25 patients. CRP increased in all seven bacteriologically positive patients and in six (32%) of the bacteriologically negative patients. CONCLUSIONS: Precise and prompt bacterial examinations are necessary in patients with CRP elevation because the origins of fever were bacteriological in only 28% of the patients with a high fever. Good prognoses may be obtained by suitable management in bacteriologically negative patients.

Adult↗
PubMed1998

[Telomerase activity in colorectal cancer--a semi-quantitative procedure].

Telomerase maintains telomere at the end of chromosome and stabilizes chromosome. It is thought to have important roles in cancer progression and cell immortality. We evaluated the role of telomerase expression in colorectal carcinogenesis. Materials included 13 colonic adenomas, 9 early colorectal cancers, 32 advanced colorectal cancers, 5 metastatic tumors, and 30 non-cancerous colon mucosas. The telomerase activity was analyzed using TRAP-eze (Oncor Inc.) for a semi-quantitative method. The positive rate of telomerase activity was 13.3% in non-cancerous colonic mucosa, 15.4% in colonic adenomas, 77.8% in early colorectal cancers, 93.8% in advanced colorectal cancers, and 100% in metastatic tumors; the mean value was 18.0, 29.9, 65.8, 97.0 and 161.3. The correlation between telomerase activity and tumor size, histologic type, or depth of invasion was noted. Sensitivity, specificity and accuracy were on the order of 89%, 98% and 93% at the cut-off level as two times the mean value of non-cancerous mucosa. Telomerase had an important role in carcinogenesis, and progression of colorectal cancer, and it was suggested to be useful for a tumor marker.

Adenocarcinoma↗
PubMed1997

Identification of Mg2+-binding sites and the role of Mg2+ on target recognition by calmodulin.

The binding of Mg2+ to calmodulin (CaM) and the effect of Mg2+ on the binding of Ca2+-CaM to target peptides were examined using two-dimensional nuclear magnetic resonance and fluorescence spectroscopic techniques. We found that Mg2+ preferentially binds to Ca2+-binding sites I and IV of CaM in the absence of Ca2+ and that Ca2+-binding site III displays the lowest affinity for Mg2+. In contrast to the marked structural transitions induced by Ca2+ binding, Mg2+ binding causes only localized conformational changes within the four Ca2+-binding loops of CaM. Therefore, Mg2+ does not seem to be able to cause significant structural effects required for the interaction of CaM with target proteins. The presence of excess Mg2+ (up to 10 mM) does not change the order and cooperativity of Ca2+ binding to CaM, and as expected, the structure of Ca2+-saturated CaM is not affected by the presence of Mg2+. However, we found that the binding of Ca2+-saturated CaM to target peptides is affected by Mg2+ with the binding affinity decreasing as the Mg2+ concentration increases. Three different peptides, corresponding to the CaM binding domain of skeletal muscle myosin light-chain kinase (MLCK), CaM-dependent cyclic nucleotide phosphodiesterase (PDE), and smooth muscle caldesmon (CaD), were examined and show different reductions in their affinities toward CaM. The CaM-binding affinity of the MLCK peptide in the presence of 50 mM Mg2+ is approximately 40-fold lower than that seen in the absence of Mg2+, and a similar response was observed for the PDE peptide. The affinity of the CaD peptide for CaM also shows a Mg2+ dependence, though to a much lower magnitude. The Mg2+-dependent decrease in the affinities between CaM and its target peptides is an intrinsic property of Mg2+ rather than a nonspecific ionic effect, as other metal ions such as Na+ do not completely replicate the effect of Mg2+. The inhibitory effect of Mg2+ on the formation of complexes between CaM and its targets may contribute to the specificity of CaM in target activation in response to cellular Ca2+ concentration fluctuations.

Amino Acid Sequence↗
PubMed1997

Arterial embolization as preoperative treatment for pulmonary aspergillosis with hemoptysis.

Pulmonary aspergillosis associated with old tuberculosis is generally resistant to treatment. Thus, if patients are treated only with conservative therapy, their condition continues to deteriorate due to repetitive hemoptysis, and may even become critical. Surgical treatment is required for these patients; however, it is extremely difficult to resect the lesion due to severe adhesions to the chest wall and vascular proliferation surrounding the lesion. We performed preoperative arterial embolization, achieving good results in three patients with hemoptysis caused by pulmonary aspergillosis. The feeding arteries were embolized using microcoils and/or gelatin sponges, and a lobectomy was safely carried out in all patients. We concluded that preoperative arterial embolization is a safe and effective technique to prevent massive hemorrhage occurring at the time of surgery.

Aged↗
PubMed1997

Thoracoscopic closure of a congenital partial pericardial defect.

We describe our technique for performing direct thoracoscopic closure of a congenital partial pericardial defect, which was successfully employed in a 15-year-old boy. This is the first such report of a procedure that is noninvasive and may therefore become the treatment of choice for patients with a small congenital pericardial defect.

Adolescent↗
PubMed1997

[A case of successful treatment of mediastinitis and prosthetic graft infection after aortic arch and thoracoabdominal aortic reconstruction].

Thoracic graft infection is a serious complication with high mortality. We report a case of successful treatment of mediastinitis and graft infection after aortic arch and thoracoabdominal aortic reconstruction. A 56-year-old woman underwent surgery for thoracoabdominal aortic aneurysm. The aneurysm was replaced with prosthetic grafts. She had a high fever on the 12th postoperative day (POD). A Chest X-ray and CT scan demonstrated fluid collection around the grafts. On the 17th POD, mediastinal drainage was performed and Staphylococcus epidermidis was detected. Because of the difficulty to replace the infected grafts, a continuous drainage from the mediastinal cavity around the grafts was induced for 17 days and sensitive antibiotics to the pathogen was administered systemically for 40 days. Inflammatory reactions were improved and her general condition was stabilized. On the 64th POD, she was discharged.

Anti-Bacterial Agents↗
PubMed1997

[Postoperative inflammatory responses to gelatin- and collagen-impregnated Dacron grafts and changes of endotoxin].

Between June, 1993 and January, 1995 a gelatin-sealed knitted Dacron (Gelseal) (g-G0, n = 7) and a collagen-sealed knitted Dacron graft (Hemashield) (g-H0, n = 8) were randomly implanted to 15 patients (pts) for replacement of thoracic aorta. We evaluated postoperative inflammatory responses and levels of Toxicolor and Endospecy which are the measurements of endotoxin. Five pts in g-G0 and 3 pts in g-H0 showed that a body temperature (BT) were above 37.5 degrees C on the 7th postoperative day (POD). In three of them (2 in g-G0 and 1 in g-H0), BT above 37.5 degrees C continued until POD 14 due to the bacterial infection. The other causes of elevation of BT were pleural effusion (2), pericardial effusion (1) and unknown origin (2). Patients without evidence of infection (n = 12) were divided into 2 groups (g-G: pts with Gelseal, n = 5, g-H: pts with Hemashield, n = 7). On POD3, postoperative BT in g-H was significantly higher than in g-G. And, on POD7, BT in g-G rose up more than in g-H. However, on POD14, BT decreased to the normal range in both groups. The values of WBC in g-G were slightly higher than in g-H and they became normal after POD7 in both groups. The levels of CRP in g-H were higher than in g-G after POD3 and in both groups they were still high on POD14. In terms of endotoxin., Toxicolor was already above the normal range from POD1 and decreased to the normal range after POD14. However, the level of Endospecy kept within normal range. In conclusion, Toxicolor-reactive substance elevates by using Gelseal and Hemashield. Its substance is not endotoxin. It would not be appropriate to consider that endotoxin is an origin of fever between POD7 and 14.

Aortic Aneurysm, Thoracic↗
PubMed1997

[Application of alpha-hANP for the management following open-heart surgery: report of two cases].

Alpha-human atrial natriuretic peptide (alpha-hANP) has a vasodilating and diuretic action. Intravenous continuous administration of alpha hANP (0.05 microgram/kg/min) was attempted for two patients with low urine output despite good hemodynamics following open-heart surgery. Following the administration of alpha-hANP, urine volume increased markedly, and central venous and pulmonary capillary wedge pressures immediately decreased. Intravenous continuous administration of alpha-hANP is useful for the management of patients associated with the volume overload following open-heart surgery.

Aged↗