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Biomedical subjects

H Masumoto

Publications and source records attributed to H Masumoto.

At least 55 records · Page 3Linked to original sources
PubMed1996

[Quadricuspid aortic valve: report of a case associated with severe aortic regurgitation].

A case of quadricuspid aortic valve is reported. A 53-year-old man was admitted to our hospital for exertional dyspnea. He had a grade 3/6 to & fro murmur along the left sternal border. Aortogram showed grade 3 aortic regurgitation. The aortic valve consisted of two equal larger cusps and two equal smaller cusps, and a supernumerary cusp located between the right and noncoronary cusps. Aortic valve replacement was performed successfully and his post operative course was uneventful. On histological examination, the resected cusps showed fibrotic thickening and no sign of previous inflammatory disease. Quadricuspid aortic valve has been extremely rare. 27 Japanese cases of quadricuspid aortic valve which were corrected surgically are reviewed.

Aortic Valve↗
PubMed1996

[A case report of right-sided cardiac and pulmonary thromboembolism treated by emergent operation].

A forty-four-year-old man with a clinical diagnosis of diabetes melitus and severe obesity (height 170 cm, weight 108 kg) was admitted to the hospital on 12th January 1995 because of acute myocardial infarction, and on 21st January, he was referred to our hospital with sudden onset of shock, bradycardia, loss of consciousness in spite of having recovered well from myocardial infarction. The echocardiography and pulmonary arteriography revealed a pulmonary embolism and a tumor in the right atrium. Administration of tissue plasminogen activator (TPA) was not sufficiently effective. An emergency operation (pulmonary arteriotomy, right atriotomy, milking of bilateral lungs) with cardiopulmonary bypass revealed a massive consecutive thrombus, which occupied the right atrium, right ventricle and bilateral pulmonary artery. The postoperative course was uneventful.

Adult↗
PubMed1995

Replication slippage between distant short repeats in Saccharomyces cerevisiae depends on the direction of replication and the RAD50 and RAD52 genes.

Small direct repeats, which are frequent in all genomes, are a potential source of genome instability. To study the occurrence and genetic control of repeat-associated deletions, we developed a system in the yeast Saccharomyces cerevisiae that was based on small direct repeats separated by either random sequences or inverted repeats. Deletions were examined in the LYS2 gene, using a set of 31- to 156-bp inserts that included inserts with no apparent potential for secondary structure as well as two quasipalindromes. All inserts were flanked by 6- to 9-bp direct repeats of LYS2 sequence, providing an opportunity for Lys+ reversion via precise excision. Reversions could arise by extended deletions involving either direct repeats or random sequences and by -1-or +2-bp frameshift mutations. The deletion breakpoints were always associated with short (3- to 9-bp) perfect or imperfect direct repeats. Compared with the POL+ strain, deletions between small direct repeats were increased as much as 100-fold, and the spectrum was changed in a temperature-sensitive DNA polymerase delta pol3-t mutant, suggesting a role for replication. The type of deletion depended on orientation relative to the origin of replication. On the basis of these results, we propose (i) that extended deletions between small repeats arise by replication slippage and (ii) that the deletions occur primarily in either the leading or lagging strand. The RAD50 and RAD52 genes, which are required for the recombinational repair of many kinds of DNA double-strand breaks, appeared to be required also for the production of up to 90% of the deletions arising between separated repeats in the pol3-t mutant, suggesting a newly identified role for these genes in genome stability and possibly replication.

Base Sequence↗
PubMed1995

Analysis of protein-DNA and protein-protein interactions of centromere protein B (CENP-B) and properties of the DNA-CENP-B complex in the cell cycle.

We previously reported that centromere protein B (CENP-B) forms a stable complex (designated complex A) containing two alphoid DNAs in vitro. Domains in the CENP-B polypeptide involved in the formation of complex A were determined in the present study with truncated derivatives expressed in Escherichia coli and in rabbit reticulocyte lysates. It was revealed by gel mobility shift analyses that polypeptides containing the NH2-terminal DNA-binding domain bind a DNA molecule as a monomer, while dimerizing at a novel hydrophobic domain in the COOH-terminal region of 59 amino acid residues. This polypeptide dimerization activity at the COOH-terminal region was also confirmed with the two-hybrid system in Saccharomyces cerevisiae cells. The results thus proved that CENP-B polypeptides form a homodimer at the COOH-terminal hydrophobic domain, each binding a DNA strand at their NH2-terminal domains. The dimerization and DNA-binding domains fall into two of the three completely conserved sequences found in human and mouse CENP-B, and complex A-forming activity was also detected in nuclear extracts of mouse cells. Metaphase-specific phosphorylation of CENP-B was also detected, but this had no effect on its complex A-forming activity. On the basis of the present results, we propose that CENP-B plays an important role in the assembly of specific centromere structures by forming unique DNA-protein complexes at the sites of CENP-B boxes on the centromeric repetitive DNA both in interphase nuclei and on mitotic chromosomes.

Amino Acid Sequence↗
PubMed1995

CENP-B binds a novel centromeric sequence in the Asian mouse Mus caroli.

Minor satellite DNA, found at Mus musculus centromeres, is not present in the genome of the Asian mouse Mus caroli. This repetitive sequence family is speculated to have a role in centromere function by providing an array of binding sites for the centromere-associated protein CENP-B. The apparent absence of CENP-B binding sites in the M. caroli genome poses a major challenge to this hypothesis. Here we describe two abundant satellite DNA sequences present at M. caroli centromeres. These satellites are organized as tandem repeat arrays, over 1 Mb in size, of either 60- or 79-bp monomers. All autosomes carry both satellites and small amounts of a sequence related to the M. musculus major satellite. The Y chromosome contains small amounts of both major satellite and the 60-bp satellite, whereas the X chromosome carries only major satellite sequences. M. caroli chromosomes segregate in M. caroli x M. musculus interspecific hybrid cell lines, indicating that the two sets of chromosomes can interact with the same mitotic spindle. Using a polyclonal CENP-B antiserum, we demonstrate that M. caroli centromeres can bind murine CENP-B in such an interspecific cell line, despite the absence of canonical 17-bp CENP-B binding sites in the M. caroli genome. Sequence analysis of the 79-bp M. caroli satellite reveals a 17-bp motif that contains all nine bases previously shown to be necessary for in vitro binding of CENP-B. This M. caroli motif binds CENP-B from HeLa cell nuclear extract in vitro, as indicated by gel mobility shift analysis. We therefore suggest that this motif also causes CENP-B to associate with M. caroli centromeres in vivo. Despite the sequence differences, M. caroli presents a third, novel mammalian centromeric sequence producing an array of binding sites for CENP-B.

Animals↗
PubMed1995

[A case report of primary pulmonary artery sarcoma].

A 49-year-old man was admitted because of dyspnea and generalized edema. CT scan pulmonary scintigram and cardiac catheter examination revealed pulmonary arterial obstruction due to a tumor associated with right heart failure. The tumor was extirpated as much as possible by a pulmonary arteriotomy under cardiopulmonary bypass. Postoperatively, right ventricular pressure decreased to about 40 mmHg while PO2 increased to the normal level. Histological examination of the tumor revealed rhabdomyosarcoma arising from the pulmonary artery. Chemotherapy consisting of a single course of CDDP and adriamycin was administered.

Humans↗
PubMed1995

[A case report of traumatic diaphragmatic hernia treated by thoracoscopic surgery].

A 56-year-old man who had been accidentally hit on the right side of the chest about 20 days previously was admitted because of intractable cough. Chest X-ray and CT scan revealed a right-sided diaphragmatic hernia and slight pneumothorax. No other hemorrhagic or perforative complications were detected. On the third hospital day, the patient underwent therapeutic thoracoscopy. Herniated transverse colon and liver were repaired through the abdominal cavity and the lacerated diaphragm was sutured through four thoracoports with video system assistance. The postoperative course was uneventful, and the patient was discharged 28 days later.

Endoscopy↗
PubMed1995

[Two cases of traumatic aneurysm of the aortic isthmus].

Two cases with blunt traumatic aneurysm of the aortic isthmus were treated recently. One was operated in early stage using heparin-bounded transient aorto-aorta bypass. The other underwent delayed operation with aorto-aorta bypass using centrifugal pump. Patch closures with Dacron fabric sealed by equine pericardium were performed in both of them with satisfactory results. We discussed the controversial problems, the timing of the operation and the method of adjunct circulation.

Adult↗
PubMed1995

[Low-dose FP (5-FU+low-dose CDDP) therapy for far advanced upper gastro-intestinal carcinoma].

Low-dose FP therapy was undertaken in 25 patients with far advanced or recurrent carcinoma (13 stomach, 7 esophagus, 3 colon, 1 gallbladder, 1 pancreas). This therapy consisted of intermittent infusion of CDDP (10 mg/body X 5 days) and continuous infusion of 5-FU (500 mg/body X 5 days) for 5 days with 2-day intervals. Patients were treated with at least 2 courses of low-dose FP therapy. Of the 25 patients, 12 with esophageal (7) or gastric (5) carcinoma, in whom curative resection was considered impossible before the operation, were subjected to neoadjuvant chemotherapy. The response rate in the neoadjuvant therapy was 100% (2 disappeared and 5 decreased in size) in the esophageal cancer and 60% (3 decreased in size) in the gastric cancer. But, in 6 patients with esophageal cancer, radiotherapy was combined. In the neoadjuvant cases, pathological effect of Grade 2 was noted in 3 of the 7 esophageal cancers and 1 of the 5 gastric cancers. Of the remaining 13 unresectable patients, a significant improvement of performance status was found in 6 patients. In 19 patients treated with low-dose FP therapy only, leukopenia of Grade 3 was not observed, and there was no nephrotoxicity. Low-dose FP therapy is safe and useful as a neoadjuvant chemotherapy for patients with far advanced esophageal or gastric cancer.

Adult↗
PubMed1994

Distribution of CENP-B boxes reflected in CREST centromere antigenic sites on long-range alpha-satellite DNA arrays of human chromosome 21.

The long-range organization of alphoid DNA arrays of human chromosome 21 was investigated using a mouse-human somatic cell hybrid. Two distinct long alphoid DNA arrays, the loci alpha 21-I and alpha 21-II, were identified in the centromere region of human chromosome 21. The alpha 21-I locus, composed of an array of 11 monomer repeat units (the 11 mer), was estimated to have a total length of 1.3 Mbp. CENP-B boxes, the binding sites of the centromere protein B (CENP-B), appeared in every other monomer unit in the 11 mer except for one place where two monomer units were repeated without any CENP-B box. The other locus, alpha 21-II, was found to be composed of alphoid subfamilies with low homology to the components of alpha 21-I locus. Five different alphoid clones presenting 32 monomer units in total were isolated from the alpha 21-II locus. Sequences of these monomer units diverged between 71-89% and no unit containing a CENP-B box was found. By analysis using two color FISH, the alpha 21-I was localized to the primary constriction, whereas the alpha 21-II site was located slightly to the short arm side. Furthermore, a combination of FISH and immunofluorescent staining indicated that the alpha 21-I site was co-localized and overlapped with the CREST centromere antigenic site on mitotic chromosomes and in interphase nuclei, while alpha 21-II was distributed broadly. Our data suggest that the locus alpha 21-I containing regularly spaced CENP-B boxes at high-frequency and the assembly site of the centromere antigens may be involved in common centromere function in both human and mouse cells.

Animals↗
PubMed1994

Lymph node metastases from carcinoma of the gastric stump.

The incidence of metastases from gastric stump cancer to various regional lymph node stations was studied after meticulous node dissection in 87 patients, who had undergone curative resection. Fifty-five (63%) patients had microscopically involved nodes. The incidence of node metastases varied between 17% and 30% in the perigastric nodes (n 1), with the same incidence in second-station lymph nodes (n 2; nodes along the left gastric, common hepatic and splenic artery, or nodes at the splenic hilus) With respect to third-station lymph nodes (n 3), metastases in nodes in the hepatoduodenal ligament (No 12) and retropancreatic nodes (No 13) were found only in 2% and 8% of the cases, respectively, but there was a high incidence of metastases (14/54, 31%) in the nodes along the mesenteric root. The overall 5-year survival rate was 48% and those for n 1 and n 2 patients were 78%, and 41%, respectively. With regard to the third level lymph node station, no 5-year survivors were seen when there was nodal involvement in node station No. 12 or No. 13. However, involvement of nodes at the root of the mesentery was associated with a 5-year survival rate of 25%. These results suggest that resection of the second level lymph nodes station must be combined with total gastrectomy and distal pancreatectomy, and that the resection of the mesenteric root is very important in patients with a tumor invading the jejunum.

Female↗
PubMed1994

[A successful surgical case of atrial septal defect with congenital factor XI deficiency].

We experienced a successful surgical case, who was a 16-year-old boy suffered from atrial septal defect with congenital factor XI deficiency. This disorder is an inherited disorder of blood coagulation characterized by a defect of the intrinsic pathway of thrombin formation and a mild to moderate bleeding tendency, but it can result in severe bleeding in surgical procedures. Open heart surgery in this disorders is rare. Preoperatively we prepared 4000 cc of fresh frozen plasma, but operated without using it. It would appear that the possibility of open heart surgery with congenital factor XI deficiency suggest in this case.

Adolescent↗
PubMed1993

[Six cases of traumatic diaphragmatic hernia].

In recent 3 years, six cases of diaphragmatic hernia caused by blunt trauma were treated surgically. Traumatic mechanics, appearance of rupture, associated injury, diagnostic procedure and surgical treatment are reviewed. All of them were survived with immediate surgical repair. Thoracoscopy is so useful to diagnose the right sided diaphragmatic hernia.

Adult↗
PubMed1993

[An emergent surgical case of the traumatic mitral regurgitation due to complete rupture of the papillary muscles].

We present a case of an emergency operation on acute MR and cardiac rupture due to a blunt thoracic trauma. This 27-year-old male suffered a severe blow to the chest when his motorcycle crashed to a tree. He was brought to this hospital by ambulance. On admission, the patient was in shock due to hypotension. Echocardiogram revealed cardiac tamponade and MR of grade 3/4. Pericardial drainage was performed immediately and his condition improved. Systolic pressure of the pulmonary artery was high at 70 mmHg which measured by Swan Ganz catheter. Isolated cardiac injury was diagnosed based on the results of various tests. A sign of acute pulmonary edema progressively deteriolated, therefore, emergent operation was performed on the same day. As cardiac fissure lesions were confirmed under cardiopulmonary bypass, we repaired the inferior side of the left ventricle and then closely examined the mitral valve. Both anterior and posterior papillary muscles were completely torn, so we immediately commenced with procedures to, replace a prosthetic valve. No complication were encountered, and the postoperative course was good. Complete ruptures of the papillary muscles due to trauma is rarely reported. We believe this case is exceptionally uncommon and worthy of reporting.

Accidents, Traffic↗