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Biomedical subjects

H Niwa

Publications and source records attributed to H Niwa.

At least 91 records · Page 5Linked to original sources
PubMed1996

Cell-cycle-dependent expression of the STK-1 gene encoding a novel murine putative protein kinase.

We have cloned a novel putative serine/threonine kinase-encoding gene, designed STK-1, from murine embryonic stem (ES) cell and testis cDNA libraries. The kinase most closely related to STK-1 is Xenopus laevis XLP46 protein kinase which shows 71% amino-acid identity to STK-1 between their kinase domains. Nevertheless, STK-1 is conserved throughout phylogeny with hybridizing sequences being detected in DNA from mammals, amphibians, insects and yeast. STK-1 mRNA is detected in testis, intestine and spleen, tissues that contain a large number of proliferating cells, but not in other tissues. All cell lines tested expressed STK-1 mRNA with levels being dependent upon proliferation rates. In NIH 3T3 cells, STK-1 is expressed in a cell-cycle-dependent fashion. These findings suggest a role for STK-1 in cell growth.

3T3 Cells↗
PubMed1996

HLA associations in otosclerosis in Japanese patients.

Otosclerosis is a disease of the otic capsule that is caused by abnormal resorption and redeposition of bony tissue. Sixty-two unrelated Japanese patients exhibiting clinical otosclerosis were typed for HLA-A, -B, -C antigens. Twenty-one of the patients were also typed for DR antigens. The frequency of HLA-Aw33 was significantly higher in otosclerosis patients than in the control group (24.2% vs 9.5%). This finding suggests that the presence of HLA-Aw33 antigens may be related to an increased susceptibility to otosclerosis or to its clinical outcome.

Adolescent↗
PubMed1996

Surgical treatment of infected thoracic and abdominal aortic aneurysms.

Twelve patients with infected aneurysms of the thoracic and abdominal aorta were evaluated. Aneurysmal location, aetiology, bacteriology and treatment modality were analysed to determine the relationship between these factors and outcome. Patients were divided into two groups based on the preoperative states of their infections. Group 1 patients (n = 7) underwent resection after resolution of their active infection. The causative organisms included Staphylococcus epidermidis (two cases). Salmonella spp. (one). Acinetobacter (one), Mycobacterium tuberculosis (one) and unknown organisms (two). Group 2 patients (n = 5) required urgent surgery because of uncontrolled sepsis despite intensive treatment with antibiotics. The causative organisms included Staphylococcus aureus (two cases). Pseudomonas aeruginosa (two) and Salmonella spp. (one). In group 1, three patients underwent closed en bloc excision of the aneurysm with in-situ graft replacement, and four underwent partial resection with in-situ graft replacement. In group 2, three patients underwent resection of the aneurysm with ligation of aorta and extra-anatomic bypass, and two underwent in-situ graft replacement after débridement of infected tissue. Overall, patients in group 1 had a mortality rate of 14% compared with 80% in group 2. These results suggest that the operative approach and method chosen to restore arterial continuity have less of an impact on outcome. The primary determinants of outcome are virulence of the infecting organism and the preoperative state of the infection.

Acinetobacter Infections↗
PubMed1996

Extended thymectomy for myasthenia gravis patients: a 20-year review.

BACKGROUND: Since 1973 we have performed extended thymectomy for myasthenia gravis because of the presence of thymic tissue in the anterior mediastinal fatty tissue. Follow-up results were reviewed and influencing factors were investigated. METHODS: Three hundred seventy-five patients with myasthenia gravis (286 nonthymomatous and 89 thymomatous) who have undergone extended thymectomies were reviewed. The status of the patients was evaluated as follows: A (remission), B (improvement), C (no change), D (deterioration), E (death due to myasthenia gravis). Evaluation was performed at 3 and 6 months, and at 1, 3, 5, 10, 15, and 20 years. The effectiveness of the operation was estimated by the remission rate (RR = A/Total number of patients evaluated) and the palliation rate (PR = A + B/Total number of patients evaluated) at each point. RESULTS: Remission rates of the nonthymomatous patients were 15.2% (3 months), 15.9% (6 months), 22.4% (1 year), 36.9% (3 years), 45.8% (5 years), 55.7% (10 years), 67.2% (15 years), and 50.0% (20 years). Remission rates in the thymomatous patients were 13.6% (3 months), 17.5% (6 months), 27.5% (1 year), 32.4% (3 years), 23.0% (5 years), 30.0% (10 years), 31.8% (15 years), and 37.5% (20 years). Absence of thymoma, younger age, and short duration of the disease were favorable prognostic factors. Thymectomy was effective also in patients with ocular myasthenia gravis. Preoperative steroid administration did not improve the outcome. CONCLUSIONS: Extended thymectomy is an excellent operative procedure for myasthenia gravis in both nonthymomatous and thymomatous patients.

Adult↗
PubMed1996

Esophageal tracheobronchoplasty for diseases of the central airway.

Three infants with congenital tracheal stenosis and three adults with various diseases of the central airway underwent esophageal tracheobronchoplasty to repair long-segment stenoses and defects. The primary operative goal was enlargement of the stenosis (n = 4), repair of the defect (n = 1), or both (n = 1). Cardiopulmonary support was required in two cases. All three infants were operated on for generalized congenital tracheal stenoses. There was one postoperative death on the fifth day. Another infant died of pneumonia 3 months after operation. Tracheal patency was excellent in two infants. One infant is well without symptoms 6 years after the operation, although balloon dilation was required three times during the first postoperative year. In the three adult patients, the primary diseases were congenital tracheal stenosis, iatrogenic injury associated with relapsing polychondritis, and malignant mediastinal tumor involving the trachea. All lesions involved both the trachea and main stem bronchi. Postoperative airway patency was excellent in all three adults, although expandable metallic stents had to be inserted in one patient. Postoperative pulmonary function was improved, particularly forced expiratory volume in 1 second and peak expiratory flow rate. Although the postoperative mortality rate was still high, especially among the infants, and prolonged postoperative ventilatory support was required for five of the six patients, long-term patency and postoperative pulmonary functional improvement are encouraging.

Adult↗
PubMed1996

Metastasizing uterine leiomyoma. A case with cardiac and pulmonary metastasis.

A case of histologically benign cardiac and pulmonary metastases from a uterine leiomyoma in a 45-year-old woman is reported. The solitary cardiac tumor consisted of five lobules with a stalk attached to the anterior papillary muscle of the right ventricle, which occupied the right ventricular cavity and almost completely obstructed the pulmonary main trunk in the systolic cycle. Multiple small nodules were found throughout both lungs. The cardiac tumor was resected at open heart surgery and open lung biopsy of the pulmonary lesion was simultaneously performed. Both of them were histologically identical to the apparently histologically benign uterine leiomyoma which had been resected five years previously. Based on the clinical and laboratory findings, it is postulated that antegrade metastases via the venous system resulted in the cardiac metastasis from the uterine leiomyoma and the secondary pulmonary metastasis from the cardiac tumor. In contrast to the light microscopic findings, ultrastructural examination suggested the possibility of malignancy associated with the presence of immature smooth muscle cells. This is the first reported case of a so-called benign metastasizing leiomyoma occurring in the heart.

Female↗
PubMed1996

Pediatric and adult tracheobronchomalacia.

Twelve cases of tracheobronchomalacia (TBM) cases were reviewed: five were pediatric, and seven were adult, two of which were due to relapsing polychondritis (RPC). In pediatric TBM, the malacic segments were short. Resection of the malacic segment in one case and laryngotracheoplasty with autologous costal cartilage in one case were unsuccessful. However, aortopexy gained good results. Two cases managed conservatively experienced gradual improvement of their symptoms. In adult TBM, plication of pars membranacea was not effective in one case. The insertion of a stent was minimally effective in one case, and distinctly in one polychondritic case. The other four cases managed conservatively have deteriorated gradually. From these findings, a new classification system is proposed.

Adult↗
PubMed1996

The regulatory subunits of fission yeast protein phosphatase 2A (PP2A) affect cell morphogenesis, cell wall synthesis and cytokinesis.

BACKGROUND: Protein phosphatase 2A (PP2A) holoenzymes have a trimeric structure, consisting of a catalytic subunit C and two regulatory subunits A (PR65) and B (PR55). In fission yeast the C subunits, being 80% identical to their mammalian counterparts, are essential for viability and negatively regulate the entry into mitosis. Genetic analyses in budding yeast and Drosophila show that the regulatory subunits are implicated in chromosome segregation, cell morphogenesis and/or cytokinesis. RESULTS: We isolated fission yeast genes paa1+ and pab1+ encoding the regulatory subunits PR65 and PR55, respectively. Gene disruption showed that the paa1+ gene was essential for viability while pab1+ was not required at 26-33 degrees C. Microtubule and actin distributions were anomalous in gene disrupted delta paa1 cells which were incapable of forming a polarized cell shape. Gene disrupted delta pab1 cells were pear- or round-shaped, and lost the polar distributions of actin and microtubules. In addition, delta pab1 cells were defective in cell wall synthesis and sporulation at permissive temperatures. At restrictive temperatures, delta pab1 cells showed an osmoremedial temperature-sensitive phenotype and delayed in cytokinesis. However, chromosome segregation was normal. CONCLUSION: Fission yeast PP2A regulatory subunit plays a critical role in cell morphogenesis, probably through regulation of the cytoskeletal network and cell wall synthesis.

Amino Acid Sequence↗
PubMed1996

The fission yeast sts5+ gene is required for maintenance of growth polarity and functionally interacts with protein kinase C and an osmosensing MAP-kinase pathway.

Cell morphogenesis is a fundamental phenomenon that involves understanding a number of biological processes including the developmental program, polarity and cell division. Fission yeast sts5 mutant cells are round rather than cylindrical with cortical actin randomly dispersed. Genetic analyses demonstrate that the sts5+ gene is required for maintenance of cell shape during interphase when the cell normally exhibits polarised growth. The sts5 mutant is not defective in cell wall integrity. Deletion of ppe1+, which encodes a type 2A-like protein phosphatase, shows similar phenotypes to the sts5 mutant and these two mutations are synthetically lethal. Multicopy plasmids containing either the protein kinase C-like gene pck1+ or the protein tyrosine phosphatase pyp1+, an inhibitor of an osmosensing Sty1/Spc1 MAP-kinase, are capable of suppressing the sts5 mutation. Consistent with this, we have found that the wis1 mutation, which is defective in a MAP-kinase kinase of the pathway, suppresses the sts5 mutation. The predicted sts5+ gene product exhibits sequence similarity to two yeast proteins, Dis3 and Ssd1 and a nematode protein, F46E8.6, where the former two yeast proteins have been shown to be involved in cell cycle control and cell morphogenesis. The sts5+ gene is not essential for cell viability, but is absolutely required for polarised growth as the gene disruption showed the same phenotypes as those of the original mutants. Overexpression of the sts5+ gene resulted in altered cell morphology and, cortical actin in these overproducing cells was also abnormal, fainter and often dispersed. Anti-Sts5 antibody specifically detected a 130 kDa protein by western blotting. A green fluorescent protein-Sts5 fusion protein localised in the cytoplasm with a discrete punctate pattern, suggesting that the Sts5 protein is a component of a novel structure. These results have indicated that the Sts5 protein is a crucial determinant of polarised growth and that it functionally interacts with the serine/threonine phosphatase, protein kinase C, and an osmosensing MAP-kinase to maintain cell morphology.

Amino Acid Sequence↗
PubMed1996

Endothelial prostanoids involved in the relaxation produced by acetylcholine in the human pulmonary artery.

In ring preparations of human pulmonary artery contracted with noradrenaline (NA), the application of acetylcholine (ACh) enhanced the tension, and withdrawal produced a large relaxation which was sustained for about 10 min and required over 20 min for recovery; the latter relaxation appeared only in the endothelium-intact preparation. Indomethacin increased the amplitude of NA contractions, changed the ACh-induced contraction to relaxation, and inhibited the ACh-induced sustained relaxation. Nitroarginine increased the amplitude of NA and ACh-induced contractions, with no significant change in the ACh-induced sustained relaxation. These effects of indomethacin and nitroarginine were observed only in the endothelium-intact preparations. In NA-contracted preparations, exogenously applied prostaglandin I2 (PGI2) produced relaxation. Thus, in human pulmonary arteries, NA and ACh activities release vasodilator prostanoids and nitroarginine-sensitive EDRF from the endothelium, and initiate direct contractile actions to smooth muscle. The prostanoid-induced relaxation is sustained for a long time after the withdrawal of ACh stimulation and can be mimicked by exogenously-applied PGI2.

Acetylcholine↗
PubMed1996

The interaction between pindolol and epinephrine contained in local anesthetic solution to the left ventricular diastolic filling velocity in normal subjects.

To evaluate the interaction between the nonselective beta-blocker, pindolol, and epinephrine contained in a local anesthetic solution, the left ventricular diastolic filling velocity was examined with pulsed Doppler echocardiography. Arterial blood pressure (BP), the R-R interval on the electrocardiogram (RR), and Doppler echo-cardiographic measurements were recorded in seven healthy volunteers after 45 micrograms of epinephrine contained in lidocaine (L-E) was injected in the maxilla after pretreatment with 5 mg of pindolol. The administration of L-E caused the elevation of BP and an increase in RR interval. Peak early (E) and peak atrial (A) filling velocities decreased, whereas isovolumic relaxation time (IVRT) and diastolic filling period (DFP) were prolonged. Although the ratio of E to A (E/A) remained unchanged, E/A/DFP was reduced. In contrast, when L-E was given without pindolol pretreatment, RR interval was shortened and BP was unchanged. The increase of both E and A velocities and the shortening of both IVRT and DFP were observed. E/A remained unchanged but E/A/DFP was increased. These results suggested that L-E caused opposite effects on the left ventricular filling velocity in the presence or absence of pindolol. We conclude that epinephrine activates the left ventricular relaxation rate but impairs it in the presence of pindolol.

Adrenergic beta-Antagonists↗
PubMed1996

The effects of the hypothalamus on hemodynamic changes elicited by vagal nerve stimulation.

To investigate the means by which neurogenic shock or syncope occur in dentistry, we determined the hemodynamic response to the activation of vagal tone in cats while they were under emotional stress. The hypothalamus and the vagal nerve were electrically stimulated to produce emotional stress and to activate vagal tone, respectively. Hemodynamic changes were recorded during vagal stimulation (Va group) and during vagal stimulation preceded by hypothalamic stimulation (AH + Va group). Although blood pressure decreased in both groups, the degree of hypotensive response in the AH + Va group was greater than the response in the Va group. Total peripheral resistance (TPR) was reduced in the AH + Va group but was increased in the Va group. The blood flow to the skeletal muscles in the AH + Va group was greater than that of the Va group. Reduced TPR, which could be due to vasodilation in the skeletal muscles, was the cause of intensified hypotension in the AH + Va group. Clearly, the hypotension produced by vagal stimulation was worsened when it was preceded by hypothalamic stimulation; this occurrence could be related to the tendency of blood to flow to the skeletal muscles.

Analysis of Variance↗
PubMed1996

[A case report of discordant lymphoma composing Hodgkin's disease and non-Hodgkin's lymphoma occurring simultaneously in mediastinum].

A 30-year-old man with discordant lymphoma, composing Hodgkin's disease and non-Hodgkin's lymphoma occurring simultaneously in mediastinum, is described. The coexistence of these two diseases is very infrequent and difficult to be treated. It has classically been considered as coincidental. Nevertheless, recent researches have referred the relationship between these two disease and possibility of transformation with each other.

Adult↗
PubMed1996

[Recurrence of AL type primary localized pulmonary amyloidosis].

A 52-year-old female, who was diagnosed primary pulmonary amyloidosis by left open lung biopsy 11 years ago, has been pointed out chest abnormal shadow in the opposite lung for 9 years. Two masses situated in the right S3a and S4 have been growing gradually with suspicion of malignancy. The right open lung biopsy revealed amyloidosis by frozen section and wedge resections were performed. Microscopic findings were compatible with AL type amyloid protein. We reported a rare case of recurrence of localized primary pulmonary amyloidosis.

Amyloidosis↗
PubMed1996

[Clinical study of nineteen thymic carcinomas].

Nineteen cases of thymic carcinoma treated in our hospital (mean age 60.0 years, seven males and twelve females) were studied clinically. Thirteen cases (68.4%) had subjective symptom; for example, chest pain, face edema or cough. Two cases (10.5%) had the associated diseases; one had gammaglobulinemia, the other one had Cushing syndrome and hypogammaglobulinemia. The histological subtypes were eleven squamous cell carcinomas (SCC) (57.9%), three undifferentiated carcinomas, two small cell carcinomas, one papillary adenocarcinoma and one lymphoepithelioma-like carcinoma. The 5 year survival rate of all cases was 42.7%. The 10 years survival rate was 21.4%. The median survival time was 56.1 months. There were one Stage I case, nine stage III cases, four stage IVa cases and five stage IVb cases. More than stage III cases were eighteen (94.7%). Five cases of stage IVb were T2N1M0, T3N1M0, T3N0M1 and T4N0M1. The 5 year survival rate of SCC was 65.6%, and that of the other subtypes was 14.3%. The cases resected completely were only eight cases (42.1%), and the 5 year survival rate of these was 70.0%. On the other hand, the rate of five cases resected incompletely was 53.3%. Metastasis occurred in 12 cases (63.2%). Metastasis occurred frequently in pleura, lymphnode, lung, bone and liver. The radiotherapy for SCC was effective and the 5 year survival rate was 83.3%. Furthermore, there were some long survivors in the cases undergone incomplete resections by postoperative radiotherapy jointly. On the other hand, the chemotherapy was not effective in our series. However, it was reported recently that the regimen including cisplatin was effective. So it was impressed that the combined therapy including surgery radiotherapy and induction chemotherapy would be important to obtain better results.

Adenocarcinoma, Papillary↗
PubMed1996

[A high concentration of itraconazole in an aspergilloma].

A 66-year-old woman was given 100 mg/day of itraconazole for eight months to treat pulmonary aspergillosis with an aspergilloma. The amount of purulent sputum decreased, but open drainage was done because the fever continued and because no improvement was seen on the chest X-ray film. No aspergillus was cultured from the surgical specimen, but fungi were observed microscopically. The concentration of itraconazole in plasma was 249 ng/ml. The concentrations in specimens of the lung and of the aspergilloma obtained by thoracotomy were 81 ng/g and 837 ng/g, respectively. The high concentration in the aspergilloma had made the fungus inactive. The itraconazole concentration may have been very high for three reasons: (1) the concentration increased in purulent fluid, (2) itraconazole easily entered the aspergilloma through the root at the cavity wall, and (3) itraconazole dissolved in lipid derived from destroyed fungus.

Administration, Oral↗
PubMed1996

[A case of hamartoma originated from the chest wall].

Hamartoma originated from the chest wall is rare. All reported cases are infant's ones. A 16-year-old man was admitted to our hospital because of chest pain and abnormal shadow in routine chest X-ray film. Thoracotomy was performed under the diagnosis of pulmonary sequestration in the left apical region. However, the operation revealed a tumor originated from the chest wall, which was diagnosed hamartoma by histological examination. Re-operation was required because of hemothorax caused by residual tumor. Second and third ribs were resected with residual tumor. There is no evidence of recurrence one year after the second operation.

Adolescent↗