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Biomedical subjects

T Oka

Publications and source records attributed to T Oka.

At least 883 records · Page 49Linked to original sources

A case of inflammatory pseudotumor of the gallbladder and bile duct.

A rare cause of obstructive jaundice is presented. A 43-yr-old man developed jaundice with fever and weight loss, and showed lymphadenopathy, reticular shadows on chest roentgenogram, deranged liver function tests, eosinophilia, low values of complement proteins, and hypergammaglobulinemia. There was a stricture throughout the bilateral hepatic ducts and common hepatic and bile ducts with dilated intrahepatic bile ducts on imagings. The walls of the gallbladder and common bile duct were thickened due to diffuse granulomatous lesions of unknown etiology, composed mainly of plasma cells, lymphocytes, and fibroblasts identical with inflammatory pseudotumor. The same histological findings also were observed in the lung and lymph nodes. Jaundice disappeared, with reduced thickening of the common bile duct wall. All clinical and laboratory abnormalities subsided after high-dose prednisolone therapy, starting when dyspnea developed. There is no similar case in the literature.

Adult↗

[Effects of neuromedin B and neuromedin C on insulin release from isolated perfused rat pancreas].

Neuromedin B and neuromedin C are novel decapeptides that have recently been isolated from porcine spinal cord and canine intestinal mucosa. We have studied the effects of neuromedin B and neuromedin C on insulin release from the isolated perfused rat pancreas. The effect of neuromedin B was detectable at a concentration of 10mM, and that of neuromedin C was detectable at a concentration of 1nM. Further increase in the concentration of neuromedin B and neuromedin C resulted in dose-dependent increases in insulin secretion. The effectiveness of neuromedin B and neuromedin C as insulinotropic agents depended on the glucose concentration; both were more effective at a higher concentration of glucose. However, insulinotropic effects of these peptides in the presence of 8.3mM glucose were limited to the first 3 min of a 20-min perfusion. These results, coupled with a recent study demonstrating bombesin-like immunoreactivity in nerves in the pancreas, suggest that neuromedin B and neuromedin C exert a direct local action on insulin secretion in the pancreas.

Amino Acid Sequence↗

Isolation and structural analysis of the mouse beta-casein gene.

Three overlapping clones containing the entire beta-casein gene were isolated from a mouse genomic library constructed in bacteriophage lambda EMBL3. Within the three clones the 6.8-kb casein gene was flanked by about 6-kb (5') and about 10-kb (3') sequences. The complete nucleotide sequence of the gene and its immediate flanking regions was determined. The gene consisted of nine exons ranging from 21 bp to 525 bp separated by introns ranging from 81 bp to 1288 bp. The length of the first exon was 43 bp, as determined by primer extension. The comparison of this sequence with that of the rat beta-casein gene showed that the overall structure of the gene was highly conserved. However, the first intron of the mouse gene was 400 bp shorter than that of the rat gene. Further analysis of homology between this gene and four other casein genes from rat and bovine revealed the presence of four highly conserved sequences. A search for the consensus sequences of transcription-regulatory elements showed that several potential regulatory sequences were present in the gene and its 5' flanking region.

Animals↗

The mechanism of action of the cytotoxic lectin from Phoradendron californicum: the RNA N-glycosidase activity of the protein.

A toxic lectin from Phoradendron californicum (PCL) was found to inactivate catalytically 60 S ribosomal subunits of rabbit reticulocytes, resulting in the inhibition of protein synthesis. To study the mechanism of action of PCL, rat liver ribosomes were treated with the toxin and the extracted rRNA was treated with aniline. A fragment containing about 450 nucleotides was released from the 28 S rRNA. Analysis of the nucleotide sequence of the fragment revealed that the aniline-sensitive phosphodiester bond was between A4324 and G4325 of the 28 S rRNA. These results indicate that PCL inactivates the ribosomes by cleaving an N-glycosidic bond at A4324 of 28 S rRNA in the ribosomes as does ricin A-chain.

Animals↗

Effects of H2-receptor antagonists on plasma aldosterone response to angiotensin II in healthy subjects; (II). Comparison of cimetidine and ranitidine.

The effects of H2-receptor antagonists, cimetidine and ranitidine, on plasma aldosterone response to angiotensin II (AII) were examined in six healthy subjects. The study was carried out on three different occasions with a two week interval. Cimetidine (400 mg), ranitidine (150 mg) or a placebo was given orally every 12 hours for 3 days in a double-blind, cross-over, double-dummy design. On the fourth day, 1 hour after the final (seventh) administration of the same agent, furosemide (20 mg) was injected intravenously. The plasma levels of renin activity (PRA), AII and aldosterone (PA) were determined for a 120 minute period after furosemide. PRA, AII and PA increased after furosemide with as well as without H2-receptor antagonist. The basal and stimulated levels of these parameters were not significantly different at any observation point among the three regimen groups. A significant correlation was observed between AII and PA with placebo (P less than 0.01) and ranitidine (P less than 0.01), but not with cimetidine (P greater than 0.05). The slope of the regression line with ranitidine was not significantly different from that of the placebo. These data indicate that the PA response to AII is blunted by cimetidine, but not by ranitidine. The current study supports the idea that this blunted response during cimetidine is independent of the blockade of H2-receptor.

Administration, Oral↗

Surgical treatment of patients with small cell carcinoma of the lung: a histochemical and immunohistochemical study.

Thirty-three patients with small cell carcinoma of the lung were treated surgically, and immunohistochemistry of the cell differentiations was examined in detail. The overall 5-year survival rate was 38% and the rates in patients with stage I or stage III were 57% and 11%, respectively (P less than 0.05). Survival rates in patients with the oat cell type and intermediate type were 24% and 44%, respectively, but with no significant difference. This carcinoma seemed to originate from primitive multipotential stem cells, i.e., those of a neuroendocrine or epithelial nature. Histochemically and immunohistochemically, argyrophilic granules and neuron-specific enolase, neuroendocrine markers, were detected more frequently in the oat cell type rather than in the intermediate type. In contrast, keratin, epithelial membrane antigen, and carcinoembryonic antigen, epithelial origin markers, were present more frequently in the intermediate type than in oat cell type. However, the difference was significant only in case of detection of argyrophilic granules and the carcinoembryonic antigen (P less than 0.05). Our current recommendation is that surgical resection should be done in the earlier stage in both subtypes. A more favorable prognosis can be expected when adjuvant chemotherapy is prescribed.

Adult↗

Adenoid cystic carcinoma of the tracheobronchial tree: clinicopathology and immunohistochemistry.

Adenoid cystic carcinoma of the tracheobronchial tree in five patients was treated surgically and the clinicopathologic manifestations and histogenesis were examined in detail. Symptoms such as cough, dyspnea, hemoptysis, and atelectasis on chest X-ray were present in four patients, and the other patient was asymptomatic. Histologically, growth patterns were classified as tubular, cribriform, and solid. The solid pattern was the most aggressive with extensive perineural invasion. Immunohistochemically, secretory component, lactoferrin, and epithelial membrane antigen were present in the cells lining the gland-like lumen of tissues with the tubular and cribriform patterns, but was rare in those with a solid pattern. Desmin and S-100 protein were detected in the nonlining cells of tissues with all three patterns. These findings suggest that this tumor originates from the myoepithelial cells of the bronchial gland and that the solid pattern was the most poorly differentiated form.

Adult↗

Single calcium-activated potassium channel in cultured mammary epithelial cells.

The properties of Ca2+-activated K+ channels in mouse mammary epithelial cells in primary culture were studied by the patch-clamp technique. In cell-attached patches, spontaneous channel openings were sometimes observed; the slope conductance of the currents was about 12 pS at negative membrane potentials with a physiological solution (152 mM Na+, 5.4 mM K+) in the pipette. External application of A23187, a calcium ionophore, activated this channel. In excised inside-out patches, the channel was activated by increasing the internal Ca2+ concentration (10(-7) to 10(-6) M). No voltage dependence of the channel was activated was observed. Internal Na+ blocked the outward K+ current in a voltage dependent manner and this block led to the non-linear I-V relationship at positive membrane potentials. The channel was blocked by internal Ba2+ (0.1 mM) and tetraethylammonium (TEA+, 20-50 mM). Ba2+ reduced the open probability but not the single channel conductance, whereas TEA+ reduced the single channel conductance. The single channel conductance of this channel, measured from the inward current with a high-K+ solution (150 mM K+) in the pipette, was large (about 40 pS), and showed inward rectification. These results suggest that this channel is different from the usual small conductance Ca2+-activated K+ channels observed in many other cells.

Animals↗

Combination therapy of cyclosporine with steroid inhibits gamma-interferon and interleukin-1 gene expression at the level of mRNA synthesis in vivo.

The present study examined the effect of cyclosporine (CsA) administered with steroid in vivo on the capacity of peripheral blood mononuclear cells (PBMC) from kidney transplant recipients to generate cytokines and their gene expression at the level of messenger RNA (mRNA). PBMC from CsA-prednisolone (Pred)-treated recipients displayed 66.9% inhibition (54.3 +/- 12.4 IU/ml; N = 42; P less than 0.01) of gamma-interferon (gamma-IFN) production compared with normal individuals (134.6 +/- 18.6 IU/ml; N = 23). Azathioprine (Az)-Pred-treated recipients displayed significantly less inhibition of gamma-IFN generation (96.0 +/- 16.1 IU/ml; N = 22; P less than 0.05) than CsA-treated patients. Macrophages (m phi) from CsA-Pred-treated recipients displayed 60.0% inhibition (5.1 +/- 0.7 U/ml; N = 20; P less than 0.01) of interleukin-1 (IL-1) production compared with normal individuals (13.0 +/- 2.9 U/ml; N = 21). These results were confirmed by the experiments using cDNA probe for gamma-IFN or IL-1 (alpha, beta). High levels of gamma-IFN mRNA in phytohemagglutinin (PHA)-stimulated PBMC or IL-1(beta) mRNA in lipopolysaccharide (LPS)-stimulated m phi were present in normal individuals but not in CsA-treated recipients as judged by hybridization to a cloned human gamma-IFN or IL-1(beta) cDNA probe. These studies demonstrated that combination therapy of CsA with steroid inhibits both gamma-IFN and IL-1 gene expression at the level of mRNA at physiological concentrations.

Cyclosporins↗

Breast cancer arising de novo in recipients of kidney allograft.

Immunosuppressive therapy is not only an etiologic factor of de novo malignant disease but is also accelerates progression of the already developed malignant disease in immunosuppressed recipients. Two cases of de novo breast cancer arising in kidney transplant recipients are reported herein. A 25 year-old woman, transplanted one haploidentical kidney transplant 4 years and 9 months ago, developed a left breast tumor. Within one month the tumor had rapidly enlarged from 3.5 cm to 8 cm in diameter by the time she underwent a radical mastectomy. Nine axillary lymph nodes were positive for metastasis. Although her graft function had been poor due to chronic rejection, she was treated with standard immunosuppressive therapy, but not adjuvant therapy. Since local recurrent disease appeared two months postoperatively, the immunosuppressive therapy was ceased and 60Co therapy started. Recurrent disease progressed rapidly, however, and she died 7 months after her operation. A 27 year-old woman, having allograft from an identical sibling, noted a right breast tumor, 8 years and 7 months later. Again the tumor had grown rapidly from 1.8 cm to 3 cm in diameter within one month. She underwent a standard radical mastectomy. One axillary lymph nodes was positive for metastasis. She has been treated with standard immunosuppressive therapy and adjuvant endocrinochemotherapy. Presently, she is alive with a well functioning graft and no disease.

Adult↗

Cyclosporine-associated microangiopathic hemolytic anemia in a renal transplant recipient.

A case of microangiopathic hemolytic anemia (MHA) associated with the immunosuppressive agent, cyclosporine, is reported herein. The patient manifested anemia with red blood cell fragmentation, hypertension, thrombocytopenia, elevation of serum LDH levels and glomerular capillary thromboses within a few days of his transplantation. Extensive treatments with urokinase and heparin proved ineffective and graftectomy was performed 7 days after his transplantation. Immunofluorescent staining failed to show immunoglobulin (IgG or IgM) or complement (C3) deposition within the glomeruli, which discriminated MHA from acute humoral-vascular rejection.

Adult↗

Successful correction of a Collett Edwards type II truncus arteriosus after bilateral pulmonary artery banding--a case report.

A case of a 4-year-old girl who underwent successful correction of a Collett Edwards type II truncus arteriosus following bilateral pulmonary artery banding is reported herein. The diagnosis of Collett Edwards type II truncus arteriosus was made when she was 5 months of age, after which the bilateral pulmonary artery banding was performed. This proved very effective and enabled elective radial surgery to be done. The radical operation was performed safely by a modified version of Rastelli's procedure. The patient had an uneventful recovery and is now well with no symptoms one year following her operation.

Child, Preschool↗

A case of endoscopic injection sclerotherapy for a bleeding duodenal varix.

A case of bleeding duodenal varix which was treated successfully with endoscopic injection sclerotherapy (EIS) is reported. The patient developed a hemorrhage from a varix in the descending portion of the duodenum two months after EIS for esophageal varices, and hemostasis was achieved using EIS with an intravericeal injection of 1% polidocanol. The duodenal varix decreased in size after EIS. Two months after EIS, a splenectomy was performed. During a 14-month follow up period after the EIS for the duodenal varix, there was no recurrent bleeding.

Adult↗

Spontaneous rupture of pyelocaliceal diverticulum.

One rare case of spontaneous rupture of pyelocaliceal diverticulum is reported in a 31-year-old Japanese man presented with a severe left flank pain. Intravenous pyelography and computerized tomography demonstrated extravasation of contrast medium from his diverticulum which contained numerous calculi. As a possible cause of spontaneous rupture of pyelocaliceal diverticulum in this case, we suggest that the paper-thin parenchyma covering the diverticulum was not strong enough to tolerate the minimum elevation of intrapelvic pressure due to the obstruction of delivered stones.

Adult↗

Inflammatory pseudotumor of the lung in adults: radiographic and clinicopathological analysis.

Inflammatory pseudotumors of the lung are rare in adults. We treated 7 patients with such tumors and describe the histological evidence, radiographic findings, and surgical treatment. In 5 patients, lung cancer was suspected preoperatively on the basis of the radiographic findings. Intraoperatively, the gross appearance of the pleura resembled lung cancer in 6 patients; the parietal pleura was involved in 3, and pleural indentation was present in the other 3. Two patients underwent partial resection, as the frozen section revealed a benign tumor, and 5 patients underwent lobectomy for what appeared to be lung cancer or a large mass. All of the patients are doing well without other therapy. We believe the lesion should be differentiated from lung cancer at operation by frozen sections, even though this proved pertinent in only 2 of the 7 patients. Limited resection is recommended if the lesion is an inflammatory pseudotumor.

Adult↗