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T Ohyama

Publications and source records attributed to T Ohyama.

At least 109 records · Page 6Linked to original sources
PubMed1998

Suppression of electrophoretic anomaly of bent DNA segments by the structural property that causes rapid migration.

Intrinsic DNA curvature is speculated to be a common feature of all satellite DNA sequences and may aid in the tight winding of DNA in constitutive heterochromatin. Several satellite DNAs, however, show unusually rapid migration in non-denaturing polyacrylamide gels, which is just the opposite behavior of that shown by curved DNA structures. Employing bovine satellite I DNA monomer, we attempted to understand the molecular mechanism of 'rapid migration'. The phenomenon of rapid migration was temperature-dependent and to a small extent polyacrylamide-concentration-dependent. Physiological or near-physiological concentrations of Mg2+and Ca2+ions bent the rapid migrating DNA segment. Predominance of purine-purine base stacking over purine-pyrimidine in nucleotide sequence was strongly indicated to be the cause of the rapid migration. Furthermore, they seemed to be implicated in the formation of induced DNA bend. We also found that the satellite I monomer contains an intrinsic DNA curvature as do many other satellites. Heretofore, the rapid migration property has concealed the presence of curvature.

Animals↗
PubMed1998

Abnormal accumulation of porphyrin derivatives in the kidneys of Long-Evans Cinnamon rats, as evidenced by microspectrophotometry.

In the study described here we have revealed an abnormal accumulation of porphyrin derivatives in the kidneys of Long-Evans Cinnamon (LEC) rats, an animal model for human Wilson's disease. In addition, we have confirmed that the derivatives emitted red-orange light in renal sections under UV excitation. This renal red-orange emission has previously been identified as luminescence from cuprous metallothioneins [Cu(I)-MTs], which also accumulate in both the kidneys and liver of LEC rats. In this study, we measured the emission spectra of the luminescence in the kidneys using microspectrophotometry. The spectra of the renal red-orange emission resembled those of porphyrin derivatives rather than those of Cu(I)-MTs. We then extracted these derivatives from the kidneys. An abundance of porphyrin derivatives was established. A significant increase in the levels of the derivatives in the liver and urine of the LEC rats was also confirmed. These results provide evidence of a heme-metabolism abnormality in LEC rats.

Animals↗
PubMed1998

Hyperthermo-chemo-hypoxic isolated liver perfusion for hepatic metastases: a possible adjuvant approach.

As a possible intraoperative adjuvant approach to treating hepatic metastases we developed a method of hyperthermo-chemo-hypoxic isolated liver perfusion in combination with hepatic resection. This method was applied to 11 patients with colorectal hepatic metastases between 1992 and 1995. One patient died on postoperative day 14 of hepatic failure (9% mortality), the cause of which was live temperature that reached 42.9 degree C, which seems to be the maximum limit for thermal toxic effect on the human liver. The other 10 patients tolerated the perfusion well, with mild hepatic and non systemic toxicity after minor or even major hepatic resection; the serum aminotransferase and total bilirubin levels returned to normal levels by postoperative day 14. Only one of eight patients (13%) for whom cytotoxic drugs were added to the perfusate (mitomycin C 10 micrograms/ml or cisplatin 2 micrograms/ml) had hepatic recurrence by 19 months after the perfusion (mean follow-up 25.8 months; median 23 months; range 8-57 months). Two patients were alive with no evidence of disease at 13 and 57 months, respectively after the perfusion; the other five patients had postperfusion extrahepatic recurrences (median: 19 months; range 7-20 months). In contrast, hepatic metastases recurred 7 and 20 months after the perfusion, respectively, in the two patients not given a cytotoxic drug.

Aged↗
PubMed1998

Comparison of hemodynamic changes in two veno-venous bypass techniques modified at the portal cannulation site.

Veno-venous bypass under total vascular exclusion is a useful technique to permit safer resection of hepatic malignancy. We describe here a retrospective study of two modified venous bypass techniques as alternatives to the conventional end-on portal cannulation technique. Portal decompression via inferior mesenteric vein access was performed in eight patients (group A), and portal decompression via a passive shunt between a branch of the mesenteric vein and the right saphenous vein was performed in a second group (group B; n = 8). Both techniques were used in hepatic resection for malignancy under total vascular exclusion. To assess the efficacy of these bypass techniques, we compared the hemodynamic changes in the two groups. There were no differences in the bypass flow between the two groups. Neither group showed any significant changes in hemodynamic parameters (including mean arterial pressure, cardiac index, systemic vascular resistance index, and pulmonary artery pressure) between the pre-bypass and bypass phases. The heart rate in the bypass phase was significantly increased compared to that in the pre-bypass phase in both groups. All hemodynamic parameters in each phase were similar in the two groups. We conclude that both techniques maintained adequate venous return and stabilized the hemodynamic changes during hepatic resection under total vascular exclusion, and that either technique can be selected according to the intraoperative situation.

Aged↗
PubMed1998

Serum interleukin-6, interleukin-8, hepatocyte growth factor, and nitric oxide changes during thoracic surgery.

Thoracic surgery creates a different environment from abdominal surgery in respect to the surgical procedure with pulmonary collapse under unilateral ventilation. Definitive evidence whether surgical trauma during thoracotomy is involved in postoperative pulmonary infections has not been clearly demonstrated. The objectives of this study were to evaluate the influence of surgical trauma during thoracotomy on postoperative infections and to investigate the clinical significance of postoperative humoral mediators in pulmonary infections after surgery. We measured serum interleukin-6 (IL-6), IL-8, hepatocyte growth factor (HGF), and nitric oxide (NO) levels in 27 patients undergoing thoracic surgery; the measurements were before and during thoracotomy, 60 minutes after reinflation, and after surgery. The patients were divided into three groups: lobectomy patients (group A), and esophagectomy patients without (group B) or with (group C) postoperative infections. The serum IL-6 and IL-8 levels in group C were markedly elevated 60 minutes after reinflation and were significantly higher than those in group A. The serum IL-8 levels during that period in group C were significantly higher than those in group B. The postoperative serum IL-6, IL-8, HGF, and NO levels were significantly higher in group c than in group B. Taken together, intraoperative hypercytokinemia, especially IL-8, following the thoracic procedure and subsequent reinflation preceded the clinical onset of postoperative infections. Hence postoperative serum IL-6, IL-8, and HGF levels may be useful predictors of infection after esophagectomy.

Biomarkers↗
PubMed1998

Repeat hepatectomy for recurrent colorectal metastases.

Recurrence rates after hepatic resection in patients with colorectal metastases are reported to range from 47% to 80%. Hepatic recurrence is seen in 35% to 50% of patients. Aggressive surgical resection appears to be a worthwhile treatment in patients with recurrent hepatic metastases to promote longer patient survival because surgical resection remains the only curative therapy available. This is a retrospective review of our experience with 15 patients undergoing repeat hepatic resection culled from 67 patients undergoing initial hepatectomy for metastatic colorectal cancer. Of 67 patients who underwent hepatectomy for colorectal hepatic metastases, 33 developed hepatic recurrence at a median interval of 23 months (range 1-176 months) after the first hepatectomy. The second hepatectomy was performed in 15 patients 5 to 29 months after the first hepatectomy, with no mortality. The mean operating time and blood loss at the second hepatectomy were similar to those at the first hepatectomy. The mean hospital stay at the second hepatectomy was significantly shorter than that at the first hepatectomy. The cumulative survival rate for the 15 patients was 42.4% at 3 years and 21.2% at 5 years, respectively, which compared favorably with the survival rate of the 67 patients who underwent initial hepatectomy. Patients who underwent the second hepatectomy had significantly higher survival rates from the first hepatectomy than the 18 patients with unresectable hepatic recurrence. Repeat hepatectomy can be performed safely and provides long-term survival rates similar to those of first hepatectomies. In appropriately selected patients, repeat hepatectomy for colorectal metastases is a worthwhile treatment.

Adult↗
PubMed1998

Effects of adrenalectomy and glucocorticoid receptor antagonist, RU38486, on pituitary growth hormone-releasing hormone receptor gene expression in rats.

We examined the effects of adrenalectomy and a glucocorticoid receptor antagonist, RU38486, on pituitary GH-releasing hormone (GRH) receptor gene expression in rats. GRH receptor mRNA levels were significantly decreased in adrenalectomized rats and replacement of dexamethasone reversed the decrease to normal. GH secretion was inhibited by adrenalectomy, whereas dexamethasone replacement failed to restore the impaired GH secretion. A high dose of RU38486 had an agonistic effect on GRH receptor mRNA levels. These results suggest that endogenous glucocorticoid is necessary for normal expression of pituitary GRH receptor mRNA in rats.

Adrenalectomy↗
PubMed1998

Clinical features of paradiverticulitis.

Colonic diverticula have been generally accepted as a source of massive hemorrhaging. Little is known, however, about fecal occult blood loss from colonic diverticula and diverticulosis. We retrospectively investigated the possibility of minor bleeding in 737 diverticula cases diagnosed from April 1989 to May 1994. Thirty-seven cases (5%) of diverticula are explained as the sources of positive occult blood testing ascertained clearly by colonoscopy. These divide into three types: (1) from intradiverticular bleeding (intradiverticulitis), (2) from peridiverticular bleeding (peridiverticulitis), and (3) from interdiverticular colonic mucosal erosion (interdiverticulitis). These findings account for the occult blood loss that we call paradiverticulitis. The two-year prospective study found 67 cases (11.3%) of paradiverticulitis in 595 diverticula cases. We concluded that paradiverticulitis is one of the causes of positive occult blood tests.

Colonoscopy↗
PubMed1998

In vivo gene transfer to mouse spermatogenic cells by deoxyribonucleic acid injection into seminiferous tubules and subsequent electroporation.

An in vivo gene transfer technique for living mouse testes was used to develop a novel transient expression assay system for transcriptional regulatory elements of spermatogenic specific genes. The combination of DNA injection into seminiferous tubules and subsequent in vivo electroporation resulted in an efficient and convenient assay system for gene expression during spermatogenesis. The transfer of the firefly luciferase reporting gene driven by the Protamine-1 (Prm-1) enhancer region revealed a significant increase in the activity of the reporter enzyme. Histochemical studies of the transfer of the lacZ gene driven by the Prm-1 enhancer showed specific lacZ expression only in haploid spermatid cells in adult testes, corresponding with the expression pattern of endogenous Prm-1. We were able to detect long-lasting transgene expression in the transfected spermatogenic cells. A group of spermatogenic differentiating cells maintained the transfected lacZ expression after more than 2 mo of transfection, suggesting that spermatogenic stem cells and/or spermatogonia could also incorporate foreign DNA and that the transgene could be transmitted to the progenitor cells derived from a transfected proliferating germ cell.

Animals↗
PubMed1998

Endoscope-assisted transaxillary removal of glandular tissue in gynecomastia.

Gynecomastia is a condition commonly associated with puberty. An endoscope-assisted transaxillary procedure was used to treat a patient with this condition. An endoscope system was inserted into a 4-cm skin incision in the axilla, and the glands and adjacent fat were removed en bloc. The resulting scar in the axilla was small and inconspicuous, and the postoperative breast contour satisfied the patient. The endoscopic system provided a useful transaxillary approach. These results show that this method appears to be the most suitable one for surgical management of gynecomastia.

Adolescent↗
PubMed1998

Breast reconstruction after mastectomy without additional scarring: application of endoscopic latissimus dorsi muscle harvest.

Breast reconstruction with the latissimus dorsi muscle flap combined with a saline-filled implant was performed. Using an endoscope, additional operative scarring due to muscle harvesting was avoided. The operative techniques were easier than usual endoscopic surgery because most of the procedures were performed under direct vision. The procedures are presented in this article.

Adult↗
PubMed1998

Molecular composition of the 16S toxin produced by a Clostridium botulinum type D strain, 1873.

The 16S toxin was purified from a Clostridium botulinum type D strain 1873 (D-1873). Furthermore, the entire nucleotide sequences of the genes coding for the 16S toxin were determined. It became clear that the purified D-1873 16S toxin consists of neurotoxin, nontoxic nonhemagglutinin (NTNH), and hemagglutinin (HA), and that HA consists of four subcomponents, HA1, HA2, HA3a, and HA3b, the same as type D strain CB16 (D-CB16) 16S toxin. The nucleotide sequences of the nontoxic components of these two strains were also found to be identical except for several bases. However, the culture supernatant and the purified 16S toxin of D-1873 showed little HA activity, unlike D-CB16, though the fractions successively eluted after the D-1873 16S toxin peak from an SP-Toyopearl 650S column showed a low level of HA activity. The main difference between D-1873 and D-CB16 HA molecules was the mobility of the HA1 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Therefore it was presumed that the loss of HA activity of D-1873 16S toxin might be caused by the differences of processing HA after the translation.

Amino Acid Sequence↗