Search PubMed⌕ Search

Biomedical subjects

M Hirano

Publications and source records attributed to M Hirano.

At least 343 records · Page 19Linked to original sources
PubMed1994

Cerebral hyperemia in MELAS.

BACKGROUND: The pathophysiology of stroke-like episodes in MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) is uncertain. CASE DESCRIPTION: We studied a 24-year-old man with MELAS who had fluent aphasia and right hemianopia. Magnetic resonance imaging and computed tomography showed a large infarction in the parietal, temporal, and occipital lobes. We performed serial planar 133Xe regional cerebral blood flow studies and single-photon emission computed tomography. Fifteen and 26 days after the stroke-like episode, there was generalized hyperperfusion, highest in infarcted areas. Four and 8 months after the stroke-like episode, the brain was still hyperemic, with highest flow in noninfarcted tissue. Reactivity to CO2 was less than normal within the infarct at 26 days but improved thereafter. In the noninfarcted region, vasomotor reactivity was impared at 4 months, when resting flows were at their peak. CONCLUSIONS: We observed generalized cerebral hyperemia and fluctuating CO2 reactivity in MELAS, possibly a consequence of local lactic acid production. In addition, this case suggests that nonquantitative functional imaging may be misleading in MELAS.

Adult↗
PubMed1994

Laryngeal behavior in unilateral superior laryngeal nerve paralysis.

Laryngeal behavior in unilateral superior laryngeal nerve (SLN) paralysis was investigated in animal models and clinical cases. The occurrence of an oblique glottis caused by rotation of the posterior glottis to the paralytic side was the main focus of this study. The animal model study employed live dogs. When the SLN on one side was sectioned, spontaneous phonation did not cause a significantly oblique glottis. When the unaffected SLN was electrically stimulated during spontaneous phonation, an oblique glottis occurred. When the SLN was unilaterally stimulated during spontaneous phonation with both SLNs sectioned, a markedly oblique glottis occurred. In the clinical study, larynges of 17 patients with SLN paralysis were examined during a test task in which a low-pitched phonation was followed by a high-pitched phonation. The purpose of this task was to activate the unaffected cricothyroid muscle during the test phonation. Five patients could not perform the test task. The glottis obviously rotated in 9 patients, whereas no significant rotation of the glottis occurred in 3. One of the latter 3 had an incomplete paralysis, and the other 2 had marked scarring around the laryngeal framework. We conclude that a unilateral SLN paralysis causes a rotation of the posterior glottis to the paralytic side when the unaffected cricothyroid muscle is markedly activated. The test consisting of low-pitched phonation followed by high-pitched phonation is a relatively simple and accurate diagnostic procedure for unilateral SLN paralysis.

Adult↗
PubMed1994

Some aspects of vocal fold bowing.

Bowing of the vocal fold frequently occurs in patients with vocal fold paralysis (VFP), those with sulcus vocalis, and those who have had laser surgery. Additionally, there are vocal folds that present bowing with no noticeable organic lesion. For the purpose of investigating the causes and mechanisms of vocal fold bowing, consecutive fiberscopic videorecordings of 127 patients with VFP, 33 with sulcus vocalis, 33 with laser surgery, and 33 with dysphonia having no clinically noticeable organic lesion were reviewed. Sixty-nine percent of the paralyzed vocal folds had bowing, and the occurrence of bowing was significantly related to the activity of the thyroarytenoid muscle as measured by electromyography. The cricothyroid activity had no significant relationship to vocal fold bowing. All vocal folds with sulcus presented with bowing. Thirty-five percent of the vocal folds that had had laser surgery had bowing. The extent of tissue removal was closely related to the occurrence of bowing. Twelve cases with no organic lesion had vocal fold bowing. Of these 12 patients, 8 were male and 9 were older than 60 years. Some aging process in the mucosa was presumed to be the cause of the bowing in this age group of patients without clinically noticeable organic lesions. Causes of vocal fold bowing in the younger group of patients without organic lesions were not determined in this study.

Age Factors↗
PubMed1994

Mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS): current concepts.

Mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes (MELAS) syndrome is one of many mitochondrially inherited multisystem diseases. The features of 110 reported mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes patients are reviewed to define the clinical spectrum of this disease. The clinical disorder, in addition to emerging concepts of genetic etiology, is promoting our understanding of mitochondrial functions. New knowledge may lead to more rational therapies. Finally, the recent revolution in the study of mitochondrial diseases may further our understanding of other degenerative disorders and even aging.

Brain↗
PubMed1994

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE): clinical, biochemical, and genetic features of an autosomal recessive mitochondrial disorder.

We studied the clinical, biochemical, and genetic features of eight patients with the autosomal recessive mitochondrial syndrome mitochondrial neurogastrointestinal encephalomyopathy (MNGIE). MNGIE is clinically characterized by ophthalmoparesis, peripheral neuropathy, leukoencephalopathy, gastrointestinal symptoms (recurrent nausea, vomiting, or diarrhea) with intestinal dysmotility, and histologically abnormal mitochondria in muscle. Brain MRI scans were consistent with leukodystrophy in seven patients examined. Nerve conduction and EMG studies were compatible with a sensorimotor neuropathy; quantitative EMG of two patients suggested a myogenic process. Muscle mitochondrial enzyme analysis revealed a partial defect of cytochrome c oxidase activity in five patients; three had additional respiratory chain enzyme defects. Two patients had isolated complex I defects, and one had normal respiratory chain function. Southern blot analysis revealed multiple deletions of mitochondrial DNA in four of eight patients.

Adolescent↗
PubMed1994

Mitochondrial DNA mutations in an outbreak of optic neuropathy in Cuba.

Since October 1991, nearly 51,000 Cubans have been afflicted in an outbreak of optic and peripheral neuropathies. To begin an investigation of the possible role of mitochondrial DNA (mtDNA) mutations in the outbreak, we studied mtDNA from 14 affected and two unaffected Cubans for the 12 mutations associated with Leber's hereditary optic neuropathy. Eleven probands (12 patients) had optic neuropathy and two had peripheral neuropathy only. We also studied two unaffected relatives of one proband. We identified two mtDNA mutations, at nucleotides 11778 and 3460, in two of the 11 probands with optic neuropathy. Although this data set is too small to reach statistically valid conclusions, it does suggest that mtDNA mutations might be contributing to the outbreak of optic neuropathy in Cuba.

Base Sequence↗
PubMed1994

Detection of AML1/ETO fusion transcript as a tool for diagnosing t(8;21) positive acute myelogenous leukemia.

The nonrandom chromosomal translocation t(8;21)(q22;q22) can be found frequently in acute myelogenous leukemia with maturation (AML-M2). The breakpoint of this translocation has been cloned and characterized, and fusion transcript AML1/ETO has been identified. Reverse transcription polymerase chain reaction (RT-PCR) can be used to amplify the breakpoint site of AML1/ETO in t(8;21)-positive AML-M2 patients. The chimeric transcript can be detected in all 16 (100%) t(8;21)-positive AML-M2 patients. In all samples, the size of the amplified DNA fragments and pattern of restriction digest were identical, indicating that the t(8;21) translocation breakpoint occurs within a single intron of the AML1 and ETO genes. Interestingly, this fusion transcript was also detected in one of 13 AML-M2 patients without the t(8;21) translocation, indicating that a masked translocation involving chromosomes 8 and 21, exists in AML. Minimal residual disease was detected by semi-nested RT-PCR in all four patients tested, who had been in complete remission for 12, 15, 34, and 52 months, respectively. These results indicate that RT-PCR amplification of the AML1/ETO fusion transcript is a powerful tool for diagnosing and monitoring minimal residual disease in AML-M2 patients.

Adolescent↗
PubMed1994

[A study of biological characteristics of large bowel adenocarcinomas showing mucin production; examination of histological differentiation and cell kinetics].

In order to clarify the biological behavior of mucin producing cancers of colon, we analyzed 32 cases showing histological heterogeneity in the tumors, by mucin histochemistry. 28 cases were mucinous adenocarcinoma, forming with tubular structures, and the remaining 4 cases were signet-ring cell carcinomas. HID-AB stain demonstrated that the mucin component was almost similar to that of normal mucosa around the cancer. In the tubular forming portions, in which polyploid or aneuploid cells were often detected, the growth fraction of cancers was significantly higher than in that of the other portions.

Adenocarcinoma, Mucinous↗
PubMed1994

Expression of P-glycoprotein in de novo acute myelogenous leukemia at initial diagnosis: results of molecular and functional assays, and correlation with treatment outcome.

We investigated the expression of P-glycoprotein (P-gp) in 52 adults with de novo acute myelogenous leukemia (AML) at the initial diagnosis. We tested 52 patients by flow cytometry using the MRK16 monoclonal antibody (MoAb). To investigate the phenotype for multidrug resistance, 41 of the patients were analyzed using rhodamine 123 (Rh123). We found that 14 (27%) of the 52 patients were positive for P-gp expression by MRK16 MoAb using a cutoff of 5% positive cells. There was a significant correlation between the results of the two analyses (p < 0.01). We suggest that flow cytometry using MRK16 MoAb is acceptable for use in detecting P-gp expression in clinical samples. Among the 52 patients, 43 (83%) obtained a complete remission (CR) and 45% of remitters were predicted to be alive and in a CR after 8 years. Although the rate of CR on the MRK16-positive patients was comparable to that of the MRK16-negative patients, the MRK16-positive patients were prone to relapse. We conclude that determination of P-gp expression of de novo AML at initial presentation did not significantly influence the outcome of treatment.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

[The influence of subclinical level of graft versus host reaction on reconstitution of host lymphoid tissues].

In this study reconstitution of lymphoid tissues under the influence of subclinical graft versus host reaction (GVHR) was investigated. Lethally irradiated recipient mice (AKR: H-2k, Mls-1a) were reconstituted with donor (B10: H-2b, Mls-1b) bone marrow (BM) cells treated with anti-Thy 1 antibody alone without complement (GVHR chimeras). When their immunological reconstitution was analysed and compared with that of AKR recipients which had been reconstituted with B10 BM treated with anti-Thy 1 and complement (Control chimera), both of these chimeras all survived more than 100 days without showing clinical signs of GVHD. Full donor chimerism was accomplished at an early stage after BM transplantation (BMT) in GVHR chimeras, whereas substantial number of recipient T cells persisted in Control chimeras during the entire observation period. No significant difference was observed in the reconstitution of the thymus and spleen between the Control and GVHR chimeras. By contrast, the reconstitution of lymph nodes (LN) in GVHR chimeras was inhibited. The apparent failure of LN reconstitution was attributed to damage of LN structure involved in homing of lymphocytes, but not attributable to damage of lymphocytes themselves. Since donor CD8+ T cells caused the damage, target antigens of this damage appeared to be H-2 class I molecules in the present system. Furthermore, clonal deletion of V beta 6+T cells that are reactive to recipient Mls-1a antigen was induced in Control chimeras but abrogated in the GVHR chimeras. The latter abrogation of clonal deletion of V beta 6+T cells appeared to result from the early disappearance of recipient T cells in these GVHR chimeras.

Animals↗
PubMed1994

Severe rhabdomyolysis as a complication of peripheral blood stem cell transplantation.

We present a case of severe rhabdomyolysis developing after peripheral blood stem cell transplantation (PBSCT) in a 17-year-old woman with Ki-1 lymphoma. Severe muscle weakness, myoglobinemia and acute renal failure developed on day 23 following PBSCT associated with painful peripheral neuropathy. Cytomegalovirus infection may have been a contributory factor.

Acute Kidney Injury↗
PubMed1994

Activation of early growth response 1 gene transcription and pp90rsk during induction of monocytic differentiation.

The present work has studied mechanisms responsible for induction of early growth response 1 (EGR-1) gene expression during monocytic differentiation of U-937 myeloid leukemia cells. Differentiation of U-937 cells with 12-O-tetradecanoylphorbol-13-acetate (TPA), an activator of the serine/threonine protein kinase C, was associated with transcriptional activation of EGR-1 promoter-reporter constructs. The EGR-1 promoter contains six CC(A/T)6GG (CArG) motifs. The two 5'-most distal CArG sequences conferred TPA inducibility. In contrast, there was little effect of TPA on EGR-1 transcription in a TPA-resistant U-937 cell variant, designated TUR. Treatment of both U-937 and TUR cells with okadaic acid, an inhibitor of serine/threonine protein phosphatases 1 and 2A, was associated with induction of monocytic differentiation and EGR-1 transcription through the 5'-most CArG element. Since these findings supported the involvement of serine/threonine protein phosphorylation in the regulation of EGR-1 expression, we studied activation of the 40S ribosomal protein S6 serine/threonine kinases, pp70S6K and pp90rsk. Although both kinases participate in regulating cell growth, there was no detectable activation of pp70S6K during TPA- or okadaic acid-induced monocytic differentiation. Moreover, rapamycin, an inhibitor of pp70S6K activation, had no effect on induction of EGR-1 expression. In contrast, analysis of pp90rsk activity by phosphorylation of a peptide derived from S6 protein demonstrated stimulation of this kinase in TPA-treated U-937, and not TUR, cells. Okadaic acid treatment of both cell types was associated with activation of pp90rsk.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Differentiation↗
PubMed1994

An acquired Robertsonian 13;15 translocation in acute myelogenous leukemia (M5b).

A 43-year-old male developed acute myelogenous leukemia (AML, M5b) with an acquired Robertsonian 13;15 translocation. He did not achieve complete remission after sequential intensive induction chemotherapy and he died 13 months later. We reviewed 7 patients with this translocation reported in the literature. Acquired Robertsonian translocations are rare, but could represent an important event in the tumorigenesis of hematologic malignancies.

Adult↗
PubMed1994

A retrospective study of 66 esophageal reconstructions using microvascular anastomoses: problems and our methods for atypical cases.

We have studied 66 patients who underwent esophageal reconstruction using microvascular anastomoses. This series comprises 28 patients with reconstruction using a free jejunal interposition between the pharynx and the cervical esophagus following pharyngolaryngoesophagectomy for hypopharyngeal carcinoma and 38 atypical patients in whom other methods of reconstruction were used. Successful transfer was achieved in 98.5 percent (65 of 66). Issues concerning atypical reconstruction and our procedures in these cases are discussed. In order to obtain adequate tension in the jejunum on the anal side, in particular, since the anastomosis is located in a deep or narrow space, autosuture instruments were used. The anastomotic leakage rate was 2.8 percent (1 of 36); the stenosis rate was 2.8 percent (1 of 36). To prevent necrosis in the trachea, a greater omentum flap was used in three patients, a mesenterium flap in two, and a pectoralis major musculocutaneous flap in one. There were no significant complications. In patients with a short gastric pedicle or in those in whom a double cancer occurred in the hypopharynx and thoracic esophagus, a gastric pedicle and a free jejunum flap were used together. As a result of this method, the incidence of any reflux of digestive juice was reduced to 0 percent (0 of 6). To reduce the possibility of an ischemic complication at the oral end of the colonic pedicle, we added a microvascular anastomosis of the colonic pedicle, thereby reducing both leakage [0 percent (0 of 9)] and necrosis [0 percent (0 of 9)]. These procedures involving microvascular anastomoses have reduced the incidence of complications in esophageal reconstructions.

Anastomosis, Surgical↗
PubMed1994

[Imaging and clinical significance of hepatic portal venous gas seen in adult patients].

In 10 adult patients with hepatic portal venous gas (HPVG), the clinical significance of HPVG and the efficacy of X-ray computed tomography (CT) were evaluated. HPVG was associated with ischemic bowel disease (n = 3), trauma (n = 4), liver abscess (n = 1), sepsis (n = 1), and unknown etiology (n = 1). The diagnostic ability of CT for the detection of HPVG was far superior to that of plain abdominal radiograph. Of 9 patients who underwent CT, HPVG located in the left hepatic lobe in all patients, and also in right hepatic lobe in 7 patients. Gas could be recognized in the left lobe and the anterior segment of the right lobe more clearly than in the posterior segment of the right lobe because of its larger amount of intravenous collection. The mortality rate of our cases was 100%. Gas was demonstrated simultaneously in the portal vein radicles and hepatic veins on CT in 4 patients with no clinical evidence of sepsis, which suggested the possibility of intraparenchymal shift of gas from the portal vein into the hepatic vein. In a single case with sepsis, gas was noted in various vessels, including arteries, in addition to the portal venous system. The authors conclude that HPVG is still a grave sign in Japan and prompt appropriate treatment is required. CT may be of great value in the early detection of HPVG and may indicate its etiology.

Abdominal Injuries↗
PubMed1993

The HOX complex neighbored by the EVX gene, as well as two other homeobox-containing genes, the GBX-class and the EN-class, are located on the same chromosomes 2 and 7 in humans.

Two newly identified human homeobox-containing genes, GBX1 and GBX2, are closely related genes, as are members of the other homeobox genes, EN-1 and EN-2. GBX1 and EN-2 have been mapped to chromosome 7q36. The present study shows that GBX2 was mapped to chromosome 2q37. EN-1 was mapped to chromosome 2q14. Moreover, two HOX complexes neighbored by the EVX gene, HOXA and HOXD, are located at chromosome 7p15-p14 and 2q31-q37, respectively. Thus, it is possible that these homeobox genes were linked to each other on an ancestral genome and that the ancestral chromosome segment was duplicated during evolution.

Amino Acid Sequence↗