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Biomedical subjects

S Katayama

Publications and source records attributed to S Katayama.

At least 505 records · Page 28Linked to original sources

Wide reconstruction of the anterior cranial base with bipedicled galeopericranial flap.

BACKGROUND: Reconstruction of facial bone fractures complicated by frontal sinus destruction must seal off the cranial cavity from the upper respiratory tract to avoid ascending infections of the intracranial contents. METHODS: We used a bipedicled galeopericranial flap for reconstruction of the extradural and subcutaneous spaces of the frontal region, which were infected with methicillin-resistant Staphylococcus aureus (MRSA) following unsuccessful coverage of the anterior cranial base with an anteriorly based pericranial flap. RESULTS: The patient healed uneventfully without infection. CONCLUSION: Because a bipedicled galeopericranial flap has abundant blood supply, it can be used to cover a wide segment of the anterior cranial base. This is the first report of the application of a bipedicled galeopericranial flap for wide reconstruction of the anterior cranial base.

Abscess↗

Outcome of long standing solitary thyroid nodules.

We investigated the outcome of long standing palpable solitary thyroid nodules by surveying 441 patients and examining 140 patients who had untreated thyroid nodules for 15 +/- 4.5 years. In our clinical survey, the most common outcome was disappearance of the thyroid nodule (38.3%). Also a significant number of patients (36.3%) underwent surgery in other hospitals. Five (1.1%) patients died of thyroid cancer. When thyroid nodules were re-examined, most nodules indeed decreased in size or disappeared; however, 13% of nodules increased in size. Ultrasound of the nodules showed that most solitary nodules were multiple and partially cystic and solid. There was an increased incidence of calcification in long standing nodules. Thyroid cancer was found by fine needle aspiration biopsy in 26.3% of enlarging nodules and 6.4% of nodules without changing size. The risk of cancer decreased when the size of the nodule decreased. A total of 15 patients with suspicion of malignancy underwent surgery. Surgical procedures were lobectomy, near total thyroidectomy, or resection of nodules with or without modified neck dissection. Seven patients had papillary carcinoma and 2 patients with benign cytology had microscopically evident papillary carcinoma. In our study, the majority of palpable solitary thyroid nodules tended to decrease in size; these nodules do not require treatment. Enlarging solid nodules are a definite risk for thyroid cancer. If the size of the nodule remains the same, judicious approach with fine needle aspiration biopsy is needed.

Adult↗

High glucose concentration suppresses mesangial laminin B2 gene expression.

To study the role of laminin in the rat mesangial cell attachment, cell adhesion to laminin-coated dishes was assayed by adding various amounts of a pentapeptide (YIGSR). YIGSR (20-100 micrograms/mL) inhibited the cell attachment to laminin-coated dishes. Mesangial laminin B2 messenger RNA (mRNA) levels were attenuated during exposure to 30 mM glucose or high osmolarity achieved by the addition of 25 mM choline chloride to 5 mM glucose (310 mOsm/kg H2O) for 3 hours. These results suggest that laminin, which may have a physiologic role in mesangial cell attachment, is produced in mesangial cells, and that the decrease of laminin B2 mRNA during hyperglycemia or exposure to high osmolarity may have some pathophysiologic significance in the development of diabetic nephropathy.

Amino Acid Sequence↗

Serum or urinary concentration of type IV collagen in diabetics.

Concentrations of serum or urinary type IV collagen, determined by sandwich enzyme immunoassay, were significantly elevated in diabetics compared to controls (P less than .01). Serum or urinary levels of type IV collagen were significantly increased in patients with microangiopathy compared to those without microvascular disease (P less than .05). Serum type IV collagen levels were also augmented in diabetics who showed an increased albumin index for 1 year. Serum levels of type IV collagen were not affected by any conditions of metabolic control. The measurement of serum or urinary type IV collagen may be a useful indicator for monitoring the development of diabetic microangiopathy, especially in early diabetic nephropathy.

Biomarkers↗

Glucose-induced production of type IV collagen and laminin P1 from cultured human umbilical vein endothelial cells.

To study the effect of high glucose on the production of type IV collagen and laminin P1 from the cultured human umbilical vein endothelial cells (HUVEC), we measured type N collagen and laminin P1 from HUVEC that were cultured under different conditions. The concentrations of type IV collagen in the cultured medium for high glucose (30 mM D-glucose) were significantly higher than those for low glucose (5.6 mM D-glucose), L-glucose (30 mM), or mannitol (30 mM). The increase of type IV collagen was dependent on the glucose concentration in the medium. The contents of type IV collagen in the cultured cells were also increased in high-glucose incubation compared with low glucose or L-glucose incubation. In contrast, the levels of laminin P1 in the medium cultured with high glucose were similar to those with low glucose or L-glucose. These results suggest that the increased production of type IV collagen may contribute to the thickening of basement membranes and may be linked to the development of diabetic nephropathy.

Cell Division↗

Configurational MR characteristics of metastatic brain tumors.

Magnetic resonance (MR) characteristics of metastatic brain tumors (MBTs) were studied using 15 cases (13 males and 2 females whose ages ranged from 32-78 yr, with the mean age of 57.8 yr; 12 adenocarcinomas, 2 squamous-cell carcinomas, 2 large-cell carcinomas). Nine cases showed hypointensities and five showed isointensities on T1-weighted images. Six cases showed markedly hypo- or hypointensities, two showed isointensities, and six showed markedly hyper- or hyperintensities on T2-weighted images. One case was markedly hyperintense on both T1- and T2-weighted images. The decrease of the signal intensity on the T2-weighted image was the main MR characteristic. A hypointense peritumoral rim was seen in four of the six hyperintense tumors on T2-weighted images. There was no correlation between the signal intensity and the histological classification.

Adenocarcinoma↗

MR findings of posterior fossa hemangioblastomas.

MR findings of five posterior fossa hemangioblastomas were reported. In the cystic type, a cyst was low intensity on T1WI and high intensity on T2WI. Mural nodule was clearly enhanced by Gd-DTPA. In the solid type, the tumor was shown as an isointense lesion on T1WI and as high intensity on T2WI, but it was markedly and homogeneously enhanced by Gd-DTPA. Multiple extremely low-intensity serpentine "flow void" signs, indicating afferent and efferent vessels, were observed within or around the tumor. These were characteristic pictures in this tumor.

Adult↗

An economical synthesis of famciclovir.

An economical synthesis of famciclovir from N-2-acetyl-7-benzylguanine by a novel regioselective alkylation with the diester cyclopropane compound was developed.

2-Aminopurine↗

Hepatitis delta virus infection in different time periods in Japan.

To investigate the prevalence of hepatitis delta virus (HDV) infection in different time periods between 1973 and 1988, antibody to hepatitis delta antigen (anti-HD) was tested for in sera collected from 1088 cases with acute or chronic hepatitis B virus (HBV) infection treated at Kure National Hospital. Between 1979 and 1983, anti-HD was first detected in 16% (four of 25 cases) of patients with acute hepatitis B, in 6.8% (11 of 161 cases) of asymptomatic HBV carriers and 26% (51 of 196 cases) of those with chronic liver disease. Except for this time period anti-HD was hardly detected. These findings indicate that sporadic HDV infections existed in this area between 1979 and 1983.

Adult↗

Abnormal prothrombin: evaluation as a tumour marker and localization in tissues of patients with hepatocellular carcinoma.

In this study, the diagnostic significance of PIVKA-II concentrations in various liver diseases was evaluated, and the use of PIVKA-II as a tumour marker for hepatocellular carcinoma (HCC) was discussed. Also, the location of abnormal prothrombin (PIVKA-II) production in HCC by indirect immunoperoxidase staining was examined. There was a good correlation between plasma and serum PIVKA-II concentrations, indicating that serum samples are adequate for PIVKA-II measurements. Fifty-four of 97 (55.7%) patients with HCC, one of 10 (10%) patients with metastatic liver cancer and two of 47 (4.3%) patients with liver cirrhosis had positive serum PIVKA-II concentrations. Positive serum PIVKA-II concentrations were found more frequently in patients with HCC than in any other liver disease (P < 0.01). Of the 97 patients with HCC, 54 (55.7%) were PIVKA-II positive, 76.3% had serum concentrations of either PIVKA-II or alpha-fetoprotein, indicating the usefulness of both tumour markers in the diagnosis of HCC. Using frozen sections of tissue specimens obtained at autopsy or during surgery, the localization of PIVKA-II was examined by indirect immunoperoxidase staining with specific anti-PIVKA-II antibodies. Tissues from 12 of 22 patients with HCC had positive PIVKA-II indirect immunoperoxidase staining only in the cancer cells. Cells with greater atypia tended to have stronger cytoplasmic staining. No specific staining was observed in non-cancerous cells. These findings suggest that PIVKA-II is synthesized specifically in hepatic cancer cells.

Adult↗