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Biomedical subjects

H Akatsuka

Publications and source records attributed to H Akatsuka.

At least 37 records · Page 2Linked to original sources
PubMed1997

Lipase secretion by bacterial hybrid ATP-binding cassette exporters: molecular recognition of the LipBCD, PrtDEF, and HasDEF exporters.

Serratia marcescens secretes several proteins, such as the lipase LipA, the metalloprotease PrtA, and the heme-binding protein HasA, which is required for heme acquisition, through two N-terminal signal peptide-independent systems that are classified as bacterial ATP-binding cassette (ABC) exporters. One is the ABC exporter for HasA, consisting of the ABC protein HasD, the membrane fusion protein (MFP) HasE, and the outer membrane protein (OMP) HasF. The second, composed of LipB (an ABC protein), LipC (an MFP), and LipD (an OMP), promotes secretion of LipA and PrtA in Escherichia coli recombinant clones. PrtA, which shows homology to the Erwinia chrysanthemi metalloproteases, is efficiently secreted by E. coli cells carrying the E. chrysanthemi ABC exporter PrtD (ABC protein)-PrtE (MFP)-PrtF (OMP). The existence of distinct systems in this bacterium and of various substrates for these systems allowed the study of protein secretion by heterologous Has, Lip, and Prt systems and by Has-Lip and Lip-Prt hybrid exporters in the genuine host as well as in E. coli. For that purpose, lipB-, lipC-, and lipD-deficient mutants were isolated from S. marcescens 8000 and their secretion of LipA and PrtA was analyzed. This demonstrated that a unique exporter, the Lip apparatus, in S. marcescens secretes both LipA and PrtA. Hybrid exporters were tested for secretion of HasA and LipA. The LipB-HasE-HasF exporter allowed secretion of LipA but not HasA, showing that the ABC protein LipB is responsible for the substrate specificity. LipA, HasA, and E. chrysanthemi PrtC were secreted via heterologous exporters and via some hybrid exporters. Analysis of secretion via hybrid exporters showed that specific interactions occur between MFPs and OMPs in these systems. These genetic experiments demonstrated that specific interactions between the ABC protein and the MFP are required for the formation of active exporters.

ATP-Binding Cassette Transporters↗
PubMed1997

Novel benzoxazole 2,4-thiazolidinediones as potent hypoglycemic agents. Synthesis and structure-activity relationships.

A new series of benzoxazole 2,4-thiazolidinediones was synthesized and evaluated for hypoglycemic activity in genetically obese and diabetic yellow KK mice. 2-Arylmethyl- and 2-(heteroarylmethyl)benzoxazole derivatives showed far more potent activity than known 2,4-thiazolidinedione derivatives such as ciglitazone, troglitazone and pioglitazone. A facile synthesis of benzoxazole 2,4-thiazolidinediones was also established using aminophenol 2,4-thiazolidinedione (11) as a key intermediate. Details of synthesis and structure-activity relationships for this series are described.

Animals↗
PubMed1997

Synoviocyte proliferation in joints of SCID mice induced by toxic shock syndrome toxin-1 stimulated T cells from patient with rheumatoid arthritis.

OBJECTIVE: To investigate the histopathological arthropathy in severe combined immunodeficient (SCID) mice given intraarticular injection of toxic shock syndrome toxin-1 (TSST-1) stimulated T cells from patients with rheumatoid arthritis (RA). METHODS: Unstimulated or TSST-1 stimulated T cell blasts (TB-TSST) of synovial fluid mononuclear cells from patients with RA (RASFMC) were intraarticularly injected into the knee joint of SCID mice. Four weeks later, the knee joints were histopathologically examined and the numbers of fibroblasts in the synovial tissues were compared with those of controls. Total RNA of the SCID mouse knee joints was isolated and Southern analysis for human T cell receptor (TCR) V beta 2 and human tumor necrosis factor-alpha (TNF-alpha) was carried out. RESULTS: Hyperplasia and increased numbers of the fibroblasts as well as neovascularization of the synovial tissues were observed in the SCID mouse knee joint tissues injected with TB-TSST of RASFMC compared with those injected with unstimulated T cells from RASFMC or with TB-TSST from peripheral blood of healthy controls. Messenger RNA for human TCR V beta 2 and TNF-alpha were detected in the SCID mouse knee joint tissues injected with TB-TSST from RASFMC. CONCLUSION: Superantigen TSST-1 stimulated T cells from RASFMC have the ability to induce chronic arthropathy with fibroblast proliferation and neovascularization in the SCID mouse.

Animals↗
PubMed1997

Clinical, morphologic, and biochemical characteristics of Chediak-Higashi syndrome in fifty-six Japanese black cattle.

OBJECTIVE: To characterize Chediak-Higashi syndrome (C-HS) in Japanese Black cattle. ANIMALS: 56 of 200 cattle with a bleeding disorder and giant granules in leukocytes. PROCEDURE: Clinical observation, CBC, hemostatic screening test, platelet aggregometry, electron microscopy, platelet constituent analysis, and ophthalmoscopic examination were done. RESULTS: Affected Japanese Black cattle had increased bleeding tendency and abnormal granules in their leukocytes. Susceptibility to infection was not increased. Cutaneous albinism was evident in 6 new-born calves, but not in most affected cattle. In all affected cattle, the tapetal fundus was pale and the nontapetal fundus was almost devoid of pigment. By electron microscopy, a remarkable decrease in the number of dense granules in platelets was observed. Functionally, collagen-induced platelet aggregation was markedly reduced. CONCLUSIONS: This bleeding disorder was diagnosed as C-HS. With regard to susceptibility to infection, albinism, and mortality, clinical manifestations of C-HS in Japanese Black cattle were moderate, compared with C-HS in human beings and Hereford cattle. CLINICAL RELEVANCE: Because an autosomal recessive mode of inheritance was documented and recessive homozygotes could be easily detected, C-HS in Japanese Black cattle can be controlled.

Adenosine Diphosphate↗
PubMed1996

Development in lung function of the affected side after repair of congenital diaphragmatic hernia.

The widespread use of newly developed techniques including extracorporeal membrane oxygenation (ECMO) has led to the survival of a number of patients with congenital diaphragmatic hernia (CDH) and associated hypoplastic lung. However, it is not fully recognized whether the hypoplastic and small lung of the affected side has the ability to develop its function after repair of CDH. The authors studied the lung function of 32 patients with CDH in whom these new methods were used. Two parameters, lung volume and pulmonary perfusion amount, were used to evaluate lung function. The former (checked by computed tomography scan) was used to evaluate the size of lung; the latter (checked by perfusion scintigram) was used to assess vascular density. The patients were divided into two groups, based on values of alveolar-arterial difference in oxygen content (AaDo2) at the time of admission. In group A (AaDo2 < 500 mm Hg; 12 cases), whose respiratory distress was mild and could be managed with ventilator care alone, the mean lung volume value for the affected side was 86% of the contralateral lung value from the initial study, and reached 93% at the time of follow-up study. The perfusion amount also exceeded 80% of the contralateral lung value from the initial study. Thus, it is likely that group A's affected-side lung is not small and has developed at a rate similar to that of the contralateral lung. However, in group B patients (AaDo2 > 500 mm Hg; 20 cases), who had severe respiratory distress at the admission and were managed with new techniques including ECMO, both lung volume and perfusion amount of the affected side initially were low in all cases (ie, mean values were 61% and 53% of contralateral-lung values, respectively). At the time of follow-up, the lung volume had increased in most cases (mean value, 88% of the contralateral lung value), but the perfusion amount of the affected side had not increased in most cases. It remained low, or decreased to below the initial value; the mean was 53% of the contralateral lung value. The initial mean perfusion: volume ratio (87%) had decreased significantly (to 62%) by the time of follow-up. This tendency was exaggerated in the 11 ECMO cases. These data might indicate that in most group B cases, the lung of the affected side has little ability to develop arterial branches, or certainly will be delayed in comparison to the contralateral lung, and that enlargement of lung volume may depend on overexpansion or emphysematous change rather than cellular growth. The present data also suggest that, in group B cases, total lung function will depend on the contralateral lung for a relatively long time.

Child↗
PubMed1996

Complete sequence and organization of the Serratia marcescens biotin operon.

The nucleotide sequence of the biotin (bio) operon of wild-type Serratia marcescens Sr41 was determined. Five ORFs were identified to encode BioA (7,8-diaminopelargonic acid aminotransferase), BioB (biotin synthase), BioF (7-keto-8-aminopelargonic acid synthase), BioC (an enzyme catalysing the synthesis of pimeloyl-CoA) and BioD (dethiobiotin synthase), in this order. The operon was deduced to be transcribed divergently to the left into bioA and to the right into the bioBFCD genes. The promoters and a common predicted operator for both bioA and bioBFCD genes were located between the bioA and bioB genes. The predicted amino acid sequences of these enzymes were similar to the sequences of the corresponding enzymes of Escherichia coli. Analysis of expression of the lacZ structural gene fused with the bioA and bioB promoters revealed that the biotin operon was subject to biotin-mediated feedback repression.

Amino Acid Sequence↗
PubMed1996

Comparison of calbindin D-28k and S-100 protein B in neuroblastoma as determined by enzyme immunoassay.

Levels of two calcium-building proteins, calbindin D-28k (calbindin-D) and S-100 protein B (S-100b), were measured by immunoassay in solid tumors obtained surgically from pediatric patients. Mean concentrations of calbindin-D and S-100b in 73 neuroblastomas (23 ganglioneuroblastomas and 50 neuroblastomas) were 10- or 25-fold higher, respectively, than those in other types of solid tumors in pediatric patients (n = 15). The mean tumor concentration of calbindin-D in patients with neuroblastoma (n = 73) was 25.1 ng/mg (range 0.20 to 317.0 ng/mg soluble protein, SE = 6.26); that of S-100b was 278.3 ng/mg (range 0.93 to 2521 ng/mg soluble protein, SE = 71.7). The mean concentration of calbindin-D (4.4 ng/mg soluble protein) was significantly (P < 0.05) lower in stage IV, the most advanced stage. The mean concentration of S-100b (74.0 ng/mg soluble protein) was lower in patients with undifferentiated neuroblastomas (P < 0.01). Tumor levels of the two calcium-binding proteins were not correlated in patients with neuroblastoma, but each was strongly correlated with outcome in patients with neuroblastoma. The evidence suggests that measurements of the calcium-binding proteins calbindin-D and S-100b would be useful for evaluating the prognosis of patients with neuroblastoma.

Adolescent↗
PubMed1995

Divergence of a flagellin protein in Serratia marcescens.

A gene (hag) encoding the flagellin (Fla) protein was cloned from Serratia marcescens (Sm) 8000, the wild-type strain of Sr41. The hag gene codes for a 348-amino-acid (aa) protein of 36.7 kDa. The predicted aa sequence showed 79% homology compared with the Fla of Sm 274 which has been reported previously [Harshey et al., Gene 79 (1989) 1-8]. Dot-matrix analysis of the Sm 8000 Fla showed that the N- and C-terminal regions of this protein were highly similar to those of other bacterial Fla. However, the aa sequence of the middle portion was quite different from that of a variant strain of the same species, Sm 274.

Amino Acid Sequence↗
PubMed1995

Tumor necrosis factor production by human T-cells stimulated with bacterial superantigens.

Tumor necrosis factor (TNF) production from T-cells stimulated with superantigenic exotoxins, staphylococcal enterotoxin B and streptococcal pyrogenic exotoxin A was investigated in the presence of cells bearing distinct isotypes of HLA class II molecules. The main T-cell subset for TNF production was investigated in parallel. Similarly high levels of TNF production were induced upon stimulation with the toxins in the presence of DR+ or DQ+ cells, but only marginal levels of TNF production were induced in the presence of DP+ cells. Although both CD4+ T-cells and CD8+ T-cells produced TNF-alpha and TNF-beta in response to toxin stimulation in the presence of HLA class II+ cells, the former T-cell subset was the major source of producers of TNF-alpha and TNF-beta.

Bacterial Proteins↗
PubMed1995

The three genes lipB, lipC, and lipD involved in the extracellular secretion of the Serratia marcescens lipase which lacks an N-terminal signal peptide.

The extracellular lipase of Serratia marcescens Sr41, lacking a typical N-terminal signal sequence, is secreted via a signal peptide-independent pathway. The 20-kb SacI DNA fragment which allowed the extracellular lipase secretion was cloned from S. marcescens by selection of a phenotype conferring the extracellular lipase activity on the Escherichia coli cells. The subcloned 6.5-kb EcoRV fragment was revealed to contain three open reading frames which are composed of 588, 443, and 437 amino acid residues constituting an operon (lipBCD). Comparisons of the deduced amino acid sequences of the lipB, lipC, and lipD genes with those of the Erwinia chrysanthemi prtDEC, prtEEC, and prtFEC genes encoding the secretion apparatus of the E. chrysanthemi protease showed 55, 46, and 42% identity, respectively. The products of the lipB and lipC genes were 54 and 45% identical to the S. marcescens hasD and hasE gene products, respectively, which were secretory components for the S. marcescens heme-binding protein and metalloprotease. In the E. coli DH5 cells, all three lipBCD genes were essential for the extracellular secretion of both S. marcescens lipase and metalloprotease proteins, both of which lack an N-terminal signal sequence and are secreted via a signal-independent pathway. Although the function of the lipD gene seemed to be analogous to those of the prtFEC and tolC genes encoding third secretory components of ABC transporters, the E. coli TolC protein, which was functional for the S. marcescens Has system, could not replace LipD in the LipB-LipC-LipD transporter reconstituted in E. coli. These results indicated that these three proteins are components of the device which allows extracellular secretion of the extracellular proteins of S. marcescens and that their style is similar to that of the PrtDEF(EC) system.

Amino Acid Sequence↗
PubMed1995

[A case of successful operation for chronic aortic dissection (DeBakey 1 type) complicated with cerebral infarction].

We report a successful operation for a patient of chronic aortic dissection complicated with cerebral infarction. A 60-year-old woman has been treated suffering from cerebral infarction for 7 years. She was referred to our hospital for abnormal chest X-ray and complaint of dry cough. The enhanced CT scan and aortogram demonstrated chronic aortic dissection (DeBakey I) extending from ascending aorta to the abdominal aortic bifurcation with occlusion of right common carotid artery and dilated ascending aorta and aortic arch. The onset of aortic dissection seemed to be, from a clinical point of view, coincident with the onset of cerebral infarction seven years ago. The replacement of the ascending aorta and aortic arch with woven Dacron velour graft were performed under hypothermic and selective cerebral perfusion. The postoperative course was uneventful although complicated with transient recurrence nerve palsy and she has been doing well.

Aortic Aneurysm, Thoracic↗
PubMed1994

The alpha subunit of GTP-binding protein G0 in neuroblastoma: correlation with advanced disease stage.

Tissue levels of the alpha subunit of G protein G0 (G0 alpha) were measured in solid tumors from pediatric patients by immunoassay. G0 alpha concentrations were determined in the supernatant obtained by centrifugation of tissue homogenates prepared in the presence (total G0 alpha) or absence of 2% sodium cholate (soluble G0 alpha). Mean G0 alpha concentrations (total G0 alpha and soluble G0 alpha) in neuroblastomas (7 ganglioneuromas, 13 ganglioneuroblastomas, and 50 neuroblastomas) were over 50-fold higher than those in other solid tumors from pediatric patients (n = 13). Mean total G0 alpha and soluble G0 alpha concentrations were 207.0 +/- 166.0 (SD) ng/mg of cholate-extractable protein and 58.6 +/- 47.0 ng/mg of soluble protein, respectively, in the neuroblastoma group (n = 70). Total G0 alpha concentration decreased with disease stage and was strongly correlated with outcome in patients with neuroblastoma. The mean total G0 alpha concentration in tumors from younger patients (< 1 year old) was 297.0 +/- 137.0 ng/mg of cholate-extractable protein, significantly higher than in tumors from older patients (140.0 +/- 155.0 ng/mg cholate-extractable protein, P < 0.0001). These results suggest that total G0 alpha levels in neuroblastoma may indicate the degree of malignancy.

Age Factors↗
PubMed1994

Versatile Escherichia coli expression vectors for production of truncated proteins.

Several expression vector plasmids containing the tac promoter, the rrnBT1T2 terminator, and the pUC ori sequence were constructed. Some of them, the pES series, have a start codon in all three reading frames and multiple cloning sites downstream of the tac promoter and have stop codons also in all three frames and additional stop codons accompanying restriction sites. They are designed for versatile expression of truncated proteins which are produced by deleting portions of the inserted DNA.

Amino Acid Sequence↗
PubMed1994

Construction of a versatile promoter analysis vector and its use for analysis of the Serratia marcescens aspartase promoter region.

A new versatile promoter analysis vector, pLGlacZ7, which contains a multiple cloning site and the lacZ structural gene in a low-copy-number plasmid pLG339, has been constructed. This plasmid, which can be stably maintained in Escherichia coli and Serratia marcescens, is useful for analysis of gene expression using lacZ gene fusions. The multiple cloning site of pLGlacZ7 is convenient for the insertion or deletion of promoter DNA fragments, the latter by using exonuclease III. The promoter of the S. marcescens aspA gene encoding aspartase was analyzed using plasmid pLGlacZ7. The S. marcescens aspA gene is composed of 1434 nucleotides and codes for a protein with a Mr of 52,543 whose predicted amino acid sequence was very similar to that of the E. coli aspA gene product. Two functional regions that may participate in the transcription of the S. marcescens aspA gene were found in the promoter region by using lacZ gene fusions in pLGlacZ7.

Amino Acid Sequence↗
PubMed1994

Gastroesophageal reflux occurring after repair of congenital diaphragmatic hernia.

Over the past 2 decades, 110 patients with congenital diaphragmatic hernia (CDH) were treated in the authors' hospital. Eighty-six survived; of these, 10 patients (11.6%) had gastroesophageal reflux (GER) after repair of CDH. Seven occurred in the past 5 years, during which time advanced intensive care including extracorporeal membrane oxygenation (ECMO) was used. Vomiting started within 4 weeks after repair of CDH in eight cases, and hiatal hernia was demonstrated in six cases. Three patients responded to conservative therapy; the other seven required antireflux surgery. Several factors are believed to be possible causes of the development of GER in CDH cases. Among them, slow pulmonary expansion of the affected side was thought to be the most important. Namely, in a case of CDH associated with severe hypoplastic lung, the esophagus may be deviated to the affected side before the lung is expanded. After expansion, the abdominal esophagus shortens, and GER or a hiatal hernia can occur in severe cases. There were seven such patients in our series of 10. With the increase in the survival rate of CDH cases associated with severe hypoplastic lung, the number of such patients also may increase. Therefore, some additional procedure to prevent the lower esophagus from sliding will be necessary in the repair of diaphragmatic hernia.

Female↗