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Biomedical subjects

S Komatsu

Publications and source records attributed to S Komatsu.

At least 73 records · Page 4Linked to original sources
PubMed1998

The involvement of Ca2+-dependent protein kinase in the regeneration of rice cultured suspension cells.

Short-term cultured cells of rice (Oryza sativa) were found to be capable of regeneration, in contrast to those obtained from long-term cultures. For clarification of the mechanism of regeneration, it was first necessary to distinguish protein kinase activity in long-term and short-term cultured cells; this activity was found greater in the former than latter. The activity was dependent on calcium, not phospholipid, phorbol ester or calmodulin. The apparent Mr of both Ca2+-dependent protein kinases was 32 kDa according to gel phosphorylation. Phosphoserine was identified in serine residues in phosphorylated histone III-S by phosphoamino acid analysis. A Ca2+-dependent protein kinase having a relative Mr of 32 kDa is thus shown to be possibly essential to regeneration in rice cultured cells.

Cell Division↗
PubMed1998

Serum level of eosinophil cationic protein in patients with chronic cough: relationship to blood eosinophils and airway hyperresponsiveness.

We measured the serum level of eosinophil cationic protein (ECP), determined the blood eosinophil count, and assessed pulmonary function by spirometry and airway responsiveness to methacholine in 80 patients with a cough lasting longer than 3 weeks without an obvious cause. The serum level of ECP was above the cutoff value of 15.7 ng/mL (mean + 2 SD in 105 healthy control adults) in 30 (37.5%) of 80 patients (high-serum-ECP group). The blood eosinophil count was significantly higher in the high-serum-ECP group than in the normal-serum-ECP group (p < 0.01). The cumulative dose of methacholine causing a 35% decrease in respiratory conductance (PD35Grs) was significantly lower in the high-serum-ECP group than in the normal-serum-ECP group (p < 0.001). The serum concentration of ECP was correlated with the blood eosinophil count and the PD35Grs (r = 0.59, p < 0.001 and r = -0.48, p < 0.001, respectively). These findings suggest a possible role for serum level of ECP in management of patients with chronic cough.

Adult↗
PubMed1997

Lymphocytes mediate TNF-alpha-induced endothelial cell adhesion molecule expression: studies on SCID and RAG-1 mutant mice.

TNF-alpha is known to elicit a rapid increase in the expression of specific endothelial cell adhesion molecules (ECAMs) within different vascular beds. The aim of this study was to determine whether lymphocytes contribute to the increased ECAM expression elicited by TNF-alpha. A dual radiolabeled mAb technique was used to quantify constitutive and TNF-alpha-induced expression of ICAM-1, VCAM-1, E-selectin, and P-selectin in different vascular beds (lung, heart, stomach, mesentery, small intestine, large intestine, and muscle) in wild-type and SCID mice. In reconstitution experiments, either whole splenocytes, T cell-enriched splenocytes, or B cell-enriched splenocytes were injected into SCID mice 48 h before TNF-alpha administration. Although the constitutive expression of ECAMs differed only slightly between wild-type and SCID mice, TNF-alpha-induced ECAM expression was markedly blunted in SCID mice compared with wild-type mice. This blunted response to TNF-alpha was also demonstrated for VCAM-1 in recombination activating gene (RAG)-1 mutant mice. Reconstitution studies revealed that administration of 50 x 10(6) splenocytes in SCID mice at 48 h before cytokine treatment restored the TNF-alpha-induced expression of VCAM-1 to levels normally observed in wild-type mice. Reconstitution with T cell- but not B cell-enriched splenocytes, also restored the TNF-alpha-induced expression of VCAM-1 in SCID mice to wild-type levels. These results implicate circulating T lymphocytes as modulators of the increased ECAM expression elicited by TNF-alpha.

Animals↗
PubMed1997

Identification of p34cdc2 kinase from sea urchin Hemicentrotus pulcherrimus and its involvement in the phosphorylation of myosin II regulatory light chain in the metaphase extract.

We present here the nucleotide sequence for a cDNA clone encoding p34cdc2 from sea urchin, Hemicentrotus pulcherrimus. The obtained cDNA comprised 301 amino acid residues that contained the PSTAIRE domain to be important for binding to cyclins. Amino acid sequence similarity between this clone and other eukaryotic cdc2 sequences averaged approximately 72%. Using p13suc1-conjugated Sepharose 4B and a selective inhibitor of p34cdc2 kinase, butyrolactone I, it was first suggested that p34cdc2 kinase is involved in the phosphorylation of MRLC at both MLCK site and two PKC sites.

Amino Acid Sequence↗
PubMed1997

Identification of MAPKAPK homolog (MAPKAPK-4) as a myosin II regulatory light-chain kinase in sea urchin egg extracts.

We identified and cloned a homolog of mammalian mitogen-activated protein kinase-activated protein kinase (MAPKAPK)-2 and -3 from sea urchin, Hemicentrotus pulcherrimus. The obtained cDNA clone was composed of 350 amino acid residues which contain MAPK phosphorylation sites and the bipartite nuclear localization signal sites in its C-terminal domain. The clone showed 65.4 and 66.7% amino acid residue identity to human MAPKAPK-2 and -3, respectively. Phylogenetic analysis revealed that the homolog can be classified into a distinct group of MAPKAPK and, therefore, the identified homolog was designated as MAPKAPK-4. Biochemical characterization was performed using recombinant glutathione S-transferase (GST)-MAPKAPK-4 fusion protein. The protein kinase activity of GST-MAPKAPK-4 was activated by MAPK and this enabled the kinase to phosphorylate both glycogen synthase N-terminal peptide and the regulatory light chain of myosin II in vitro. Northern blot analysis showed that MAPKAPK-4 was expressed throughout the development of sea urchin embryos. These observations suggest that MAPKAPK-4 may play an important role in the regulation of myosin II activity during the development of sea urchin.

Amino Acid Sequence↗
PubMed1997

The reinforcement of tracheoplasty with a self-fascia lata and Gelatin-Resorcin-Formal (GRF) glue.

We examined the efficacy of protecting the suture line in tracheoplasty by using a self-fascia lata and Gelatin-Resorcin-Formal (GRF) glue. Fifteen dogs underwent a resection of four rings of the trachea and reconstruction, and we then observed them for one month; group A (n = 5) without reinforcement, group B (n = 5) with a self-fascia-lata spread with GRF glue, and group C (n = 5) with only a self-fascia-lata. In the reinforced dogs (group B, three cases, and group C, five cases), in which the continuity of the suture line had been conserved, eight cases were resistant to pressures of from 240 mmHg to 300 mmHg, and two cases (both in group B) which had a partial discontinuity of the suture line were resistant to the same pressure of 160 mmHg. But in the five dogs without reinforcement (group A), four died from infection due to leakage of the trachea within 2 weeks; only one that had a continuity of the suture line survived and was resistant to pressure of 300 mmHg. These results show that a reinforcement of tracheoplasty using a self-fascia lata and GRF glue is useful for preventing air leakage from the suture line.

Animals↗
PubMed1997

Aortic arch operation using selective cerebral perfusion for nondissecting thoracic aneurysm.

BACKGROUND: Risks of increasing mortality and disability in aortic arch operations using the selective cerebral perfusion method for nondissecting aneurysm have not yet been determined. A multicenter, retrospective study was employed. METHODS: The subjects were 143 patients who were admitted to one of the nine cardiovascular centers between January 1988 and December 1993, including 15 with ruptured aneurysm. A graft replacement of the transverse aortic arch or distal arch was performed in 80 patients, extensive aortic reconstruction comprising simultaneous replacement of the ascending or descending thoracic aorta (or both) in 46, and patch repair of involved arch in 17. The mean postoperative follow-up period was 19 months. RESULTS: Hospital mortality was 36/143 patients (25.2%). Univariate analysis revealed that age of 70 years or more, ruptured aneurysm, and renal dysfunction affected hospital mortality. Neurologic deficits were noted in 15 patients (10.5%). Reoperation was performed in 13 patients for residual distal aneurysm or false aneurysm. Late death occurred in 10 patients and were due to vascular complications in 6. Multivariate analysis confirmed that aneurysmal rupture and renal dysfunction were independent predictors for vascular death including hospital mortality. CONCLUSIONS: The present study confirmed that age, aneurysmal rupture, and renal dysfunction were significant predictors for mortality and disability in the aortic arch operation using selective cerebral perfusion for nondissecting thoracic aneurysm.

Aged↗
PubMed1997

Operation for nondissecting aneurysm in the descending thoracic aorta.

BACKGROUND: Little is known about the risks of mortality and morbidity after descending thoracic aortic aneurysm repair using left heart bypass and temporary arterioarterial bypass. METHODS: A multicenter, retrospective study was performed on 120 patients who were admitted to one of nine cardiovascular centers between January 1988 and December 1993 and underwent operation for nondissecting thoracic aortic aneurysm. The present series included 10 patients with ruptured aneurysm. Graft replacement was performed in 95 patients, patch repair in 22, and suture of the ruptured aorta in 3. Venoarterial bypass was used in 45 patients, left heart bypass in 56, and temporary arterioarterial bypass in 19 as circulatory support. The mean postoperative follow-up period was 30 +/- 21 months. RESULTS: Hospital mortality occurred in 7 patients (5.8%). Univariate analysis revealed that only aneurysmal rupture was related to hospital mortality. Brain or cord injury was observed in 4. Of nine deaths that occurred after discharge, five were related to aneurysm and two were due to vascular event. No significant difference was noticed in probability of survival according to the circulatory supporting method. Only aneurysmal rupture affected probability of survival. Multivariate analysis revealed that aneurysmal rupture was the only independent predictor for vascular death including hospital mortality. CONCLUSIONS: The present study confirms that aneurysmal rupture is a significant predictor for mortality and morbidity in aortic operations for nondissecting descending thoracic aneurysm, and that a similarly good outcome would be expected when using left heart bypass, temporary arterioarterial bypass, or venoarterial bypass.

Aged↗
PubMed1997

Influence of oxygen in inflation gas during lung ischemia on ischemia-reperfusion injury.

OBJECTIVES: Previous studies have reported that hyperinflation during lung ischemia improves pulmonary function after reperfusion. However, it has not been clarified whether hyperinflation itself or oxygen in inflation gas causes good pulmonary function. The aim of this study is to evaluate the effect of oxygen in pulmonary inflation gas during lung ischemia on ischemia-reperfusion injury. METHODS: Twenty-one mongrel dogs were randomly divided into three groups: the lung during a 90-minute period of warm ischemia was inflated to 30 cm H2O with 100% oxygen in group A and 100% nitrogen in group B; it was not inflated in group C. Pulmonary function and hemodynamics were measured before ischemia and 1, 2, and 3 hours after reperfusion. Total protein and phosphorus of phospholipid in bronchoalveolar lavage fluid were measured 210 minutes after reperfusion. Adenine nucleotide levels in lung tissue were estimated 210 minutes after reperfusion. RESULTS: No significant differences in pulmonary function and hemodynamics were noted between group A and group B, but these two groups had significantly better pulmonary function and hemodynamics than group C. No significant differences were detected in the concentrations of total protein and phosphorus of phospholipids in bronchoalveolar lavage fluid and in adenine nucleotide levels of lung tissue after reperfusion among the three groups. CONCLUSIONS: The results indicate that pulmonary inflation during warm ischemia improves pulmonary function and hemodynamics after reperfusion in this model. The effect is caused by inflation itself and is not due to oxygen as a metabolic substrate during warm ischemia.

Adenine Nucleotides↗
PubMed1997

Varietal differences in protein phosphorylation during cold treatment of rice leaves.

The effects of cold stress on protein phosphorylation in leaves of rice (Oryza sativa) seedlings were investigated. Two-week-old rice seedlings were exposed to low temperature (5 degrees) for 6 hr at a relative humidity of 100%. The leaf protein extracts were phosphorylated in vitro. Cold stress stimulated the phosphorylation of a 60 kDa protein in the cold-sensitive rice variety, IR36. In the cold-tolerant rice variety, Kitaibuki, this protein had already been phosphorylated. For greater clarificating of these changes, the effects of cold on rice varieties differing in cold susceptibility were examined. Cold-sensitive rice varieties showed similar the protein phosphorylation in contrast to the cold-tolerant rice varieties.

Cold Temperature↗
PubMed1997

Effects of intestinal stasis on intercellular adhesion molecule 1 expression in the rat: role of enteric bacteria.

BACKGROUND & AIMS: The mechanisms underlying the inflammatory changes associated with intestinal stasis are poorly understood. The objective of this study was to assess whether endothelial expression of intercellular adhesion molecule 1 (ICAM-1) and leukocyte recruitment are altered after intestinal stasis. METHODS: ICAM-1 expression and granulocyte recruitment were quantified in different tissues of Sprague-Dawley rats using the double-radiolabeled monoclonal antibody technique and peroxidase activity, respectively. RESULTS: Both constitutive and endotoxin-induced ICAM-1 expression were significantly higher in the cecum than in distal colon, a finding that cannot be explained by a difference in endothelial surface area between the two organs. Surgical procedures to improve cecal stool flow (cecostomy, ileocecostomy) elicited a significant decrease in constitutive ICAM-1 expression in both cecum and distal colon. Tissue peroxidase activity was normally higher in cecum than in distal colon, and this difference was significantly reduced by ileocecostomy. Oral administration of antibiotics (kanamycin and/or metronidazole for 2 days) significantly reduced constitutive ICAM-1 expression in the cecum, but not in the distal colon. CONCLUSIONS: This study indicates that intestinal stasis is associated with an increased expression of ICAM-1 and granulocyte infiltration, which may be mediated by enteric bacteria.

Animals↗
PubMed1997

Working pressure for full balloon inflation during intraaortic balloon pumping.

With changes in heart rate and mean aortic pressure, an intraaortic balloon (IAB) works with incomplete inflation. The effects of initial peak positive pressure and plateau holding positive pressure on IAB volume were investigated and minimum pressures necessary to inflate an IAB to a desired volume were established with a standard IAB catheter (Datascope type, 9.5 Fr, 40 ml). Initial peak pressure greater than 200 mm Hg was adequate to attain the desired volume of the IAB. Plateau positive pressure should be altered in accordance with hemodynamic changes.

Analysis of Variance↗
PubMed1997

Enhanced mucosal permeability and nitric oxide synthase activity in jejunum of mast cell deficient mice.

BACKGROUND: Recent reports have described a modulating influence of nitric oxide (NO) on intestinal mucosal permeability and have implicated a role for mast cells in this NO mediated process. AIMS: To assess further the contribution of mast cells to the mucosal permeability changes elicited by the NO synthase (NOS) inhibitor NG-nitro-L-arginine methylester (L-NAME), using mast cell deficient (W/Wv) and mast cell replete mice (+/+). METHODS: Chromium-51 EDTA clearance (from blood to jejunal lumen), jejunal NOS and myeloperoxidase (MPO) activities, and plasma nitrate/nitrite levels were monitored. RESULTS: The increased EDTA clearance elicited by intraluminal L-NAME in W/Wv mice (4.4-fold) was significantly greater than the response observed in control (+/+) mice (1.8-fold). The exacerbated response in W/Wv mice was greatly attenuated by pretreatment with either dexamethasone (1.3-fold) or the selective inducible NOS inhibitor, aminoguanidine (1.4-fold), and partially attenuated by the mast cell stabiliser, lodoxamide (2.9-fold). Jejunal inducible NOS activity was significantly higher in W/Wv than in +/+ mice, while jejunal MPO was lower in W/Wv mice than in +/+ mice, suggesting that the higher inducible NOS in W/Wv does not result from the recruitment of inflammatory cells into the gut. The higher inducible NOS activity in the jejunum of W/Wv was significantly reduced by dexamethasone treatment. CONCLUSIONS: Our results suggest that mast cells normally serve to inhibit inducible NOS activity tonically in the gut and that inhibitors of NOS elicit a larger permeability response when this tonic inhibitory influence is released by mast cell depletion.

Animals↗
PubMed1997

Effects of chronic arterial hypertension on constitutive and induced intercellular adhesion molecule-1 expression in vivo.

Recent reports indicate that bacterial endotoxin (lipopolysaccharide) and cytokines elicit a more profound increase in the surface expression of intercellular adhesion molecule-1 (ICAM-1) in cultured endothelial cells derived from spontaneously hypertensive (SHR) versus normotensive Wistar-Kyoto rats (WKY). Our objective in this study was to characterize and compare in vivo ICAM-1 expression in SHR and WKY under basal conditions and after 5 hours of endothelial cell activation with either lipopolysaccharide (5 mg/kg i.p.) or tumor necrosis factor-alpha (TNF-alpha; 1, 5, and 10 micrograms/kg i.p.). ICAM-1 expression was quantified in different tissues by the double-radiolabeled monoclonal antibody technique. When constitutive (baseline) ICAM-1 expression was corrected for endothelial cell surface area, significantly higher values were noted in SHR than WKY but only in splanchnic organs. Lipopolysaccharide and TNF-alpha elicited significant increases in ICAM-1 expression in all tissues of both WKY and SHR. However, the magnitude of the lipopolysaccharide-induced ICAM-1 upregulation in heart, stomach, skeletal muscle, and brain was significantly lower in SHR than WKY. A similar blunted ICAM-1 upregulation was noted in the stomach of SHR after administration of 5 micrograms/kg TNF-alpha. The differences in induced ICAM-1 expression between SHR and WKY do not appear to be due to differences in endothelial cell surface area or plasma glucocorticoid levels. These results suggest that chronic arterial hypertension results in altered ICAM-1 expression on the endothelium, which may contribute to the abnormal inflammatory responses associated with this disease.

Animals↗
PubMed1997

Ontogeny of somatostatin cells in the rat fetal pancreas.

The growth pattern of somatostatin cells was clarified immunohistochemically from day 12 to day 18 of gestation in the rat fetus. On day 12, somatostatin cells first appeared within the pancreatic anlage. The total number of somatostatin cells was gradually increased from day 12 to day 16 and rapidly increased thereafter. It may be concluded that such a sequence of events of development in somatostatin cells occurs in a fashion similar to that in B cells.

Animals↗
PubMed1997

[Extended total aortic arch replacement involving the proximal descending aorta through a median sternotomy].

From January 1986 to September 1995, total aortic arch replacement (TAR) for aortic dissection was performed using selective cerebral perfusion in 151 patients. In 18 patients, the surgical procedures of extended aortic arch replacement (EAR) involving the proximal descending aorta through a median sternotomy were applied. To evaluate the outcome of EAR, the early and late results were compared with those of non-extended aortic arch replacements (NAR) through a median sternotomy (n = 66). The early mortality rates for EAR and NAR were 5.6% and 16.7%, respectively (NS); the lower rate for EAR may be due to the fact that EAR were performed more recently than NAR. The differences between EAR and NAR with respect to the amount of blood transfused intraoperatively and the respiratory index at 12 hours after surgery were not statistically significant. In addition, the extracorporeal bypass time in EAR was no longer than that in NAR. Thus, as compared with the NAR procedure, the EAR procedure did not have a negative effect on early outcome. Regarding late results, the actuarial survival rates after EAR and NAR, respectively were 87% and 72% at 1 year, 87% and 69% at 3 years (NS). The early thrombo-occlusion rates of the remaining false lumens after TAR in broad aortic dissections were 56% after EAR and 33% after NAR (p = 0.21). These results suggest that EAR may be a more useful procedure in some patients requiring TAR.

Aged↗