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Biomedical subjects

T Horiuchi

Publications and source records attributed to T Horiuchi.

At least 793 records · Page 44Linked to original sources
PubMedDate not supplied

High-level expression and characterization of hepatitis B virus surface antigen in silkworm using a baculovirus vector.

The Bombyx mori nuclear polyhedrosis virus (BmNPV) in the silkworm was used successfully for mass production of biologically active foreign genes under the control of the polyhedrin promoter. This system was adapted for the production of large amounts of hepatitis B virus surface antigens (HBsAg). The DNA fragments coded for the middle protein, which is composed of the S protein with the pre-S2 region, were cloned, the signal protein gene of beta-IFN was added, and both were inserted into a cloning vector. After co-transfection with wild-type BmNPV, stable recombinant viruses were isolated by the limiting dilution method. Infected silkworm larvae with the recombinants expressed HBsAg at high levels (400-600 micrograms/ml). These products, consisting of two polypeptides with molecular weights of approximately 25,000 (p25) and glycosylated P25 (GP28), were purified as assembled 22-nm particles. We demonstrated that HBsAg from silkworms consists of S protein with 7 amino acids of Pre-S2.

Amino Acid Sequence↗
PubMedDate not supplied

Two cases of malignant lymphoma complicated by hemophagocytosis resembling orbital cellulitis.

Two patients with malignant lymphoma complicated by hemophagocytic syndrome (HPS) are reported. Their clinical signs at onset were similar to those of orbital cellulitis. Lymphoma complicated by hemophagocytosis is called lymphoma-associated hemophagocytic syndrome (LAHS) and its prognosis is reported to be very poor. As far as we know, this is the first report in the ophthalmological field. In our patients, we suspected that the lesions occurred from the orbit or skin of this area. The first patient was a 22-year-old man and the second patient a 16-year-old girl. The diagnosis was very difficult at the onset of disease. They died within 6 months after the first ophthalmological examination. When orbital cellulitis is suspected and antibiotic therapy is ineffective, we should suspect HPS and should examine serum ferritin, which is a good marker of HPS. Early biopsy and consultation with a hematologist are very important.

Adolescent↗
PubMedDate not supplied

Spike-based VLSI modeling of the ILD system in the echolocating bat.

The azimuthal localization of objects by echolocating bats is based on the difference of echo intensity received at the two ears, known as the interaural level difference (ILD). Mimicking the neural circuitry in the bat associated with the computation of ILD, we have constructed a spike-based VLSI model that can produce responses similar to those seen in the lateral superior olive (LSO) and some parts of the inferior colliculus (IC). We further explore some of the interesting computational consequences of the dynamics of both synapses and cellular mechanisms.

Action Potentials↗
PubMedDate not supplied

Production of human alpha-interferon in silkworm using a baculovirus vector.

Microorganisms are generally used for mass production of foreign gene products, but multicellular organisms such as plants have been proposed as an economical alternative. The silkworm may be useful in this context as it can be cultured easily and at low cost. We have therefore developed a virus vector to introduce foreign genes, for example, the gene for human alpha-interferon (IFN-alpha), into silkworms. We used the baculovirus Bombyx mori nuclear polyhedrosis virus (BmNPV) which has a large (greater than 100 kilobases, kb) double-stranded circular DNA genome within its rod-shaped capsid. Baculoviruses have been used previously as vectors for expression of beta-interferon and beta-galactosidase in established cell lines. Although BmNPV has not been used previously as an expression vector, it has an advantage over the baculovirus Autographa californica NPV in that it has a narrower host range and will not grow in wild insect pests in the field. In the present study, the polyhedrin gene encoding the major inclusion body protein of BmNPV was identified by hybridization with complementary DNA and cloned in a plasmid. For insertion of foreign genes, we constructed a recombinant plasmid carrying a polylinker linked to the promoter of the polyhedrin gene, and inserted the IFN-alpha gene into this plasmid. The resulting plasmid and the BmNPV genomic DNA were co-transfected into BM-N cells, and stable recombinant viruses isolated by plaque assay on BM-N cells. The recombinant virus replicated in silkworm larvae, which synthesized as much as 5 X 10(7) units (approximately 50 micrograms) of interferon in their haemolymph.

Amino Acid Sequence↗
PubMedDate not supplied

Construction of a plasmid vector for the regulatable high level expression of eukaryotic genes in Escherichia coli: an application to overproduction of chicken lysozyme.

A novel expression vector pKP1500 for synthesizing unfused protein in Escherichia coli was constructed. pKP1500 perserves the tac promoter, the lacZ SD sequence, unique restriction sites (EcoRI, SmaI, BamHI, SalI, PstI and HindIII) and the rrnB terminators of pKK223-3, but the replication origin is replaced with that of pUC9. Construction of this plasmid is based upon the observation that the copy number control of pUC9 is temperature dependent. At 28 degrees C, the copy number of pKP1500 is less than 25 per chromosome, approximately the same copy number as that of pKK223-3, which contains the replication origin of pBR322, whereas at 42 degrees C, the copy number increases about 10 times and reaches up to 230 copies per chromosome. The main advantage of this system is that the temperature-dependent copy control and regulatable expression of the tac promoter make cells carrying pKP1500 derivatives stable against selective pressure by detrimental overproduction of foreign proteins at a low temperature and permits high expression of cloned DNAs at a high temperature. When chicken lysozyme cDNA carrying the initiation codon (ATG) immediately upstream from the Lys1 codon was inserted downstream from the tac promoter and the SD sequence, the pKP1500 derivative produced lysozyme at about 25% of the total cellular proteins. This value is more than 10 times higher than that obtained with the pKK223-3 derivative carrying the same lysozyme cDNA. By comparison, the expression of eukaryotic genes from the tac promoter reported by others has usually been less than a few % of the total cellular protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Point mutation of alanine (31) to valine prohibits the folding of reduced lysozyme by sulfhydryl-disulfide interchange.

In the preceding paper in this issue, we described the overproduction of one mutant chicken lysozyme in Escherichia coli. Since this lysozyme contained two amino acid substitutions (Ala31----Val and Asn106----Ser) in addition to an extra methionine residue at the NH2-terminus, the substituted amino acid residues were converted back to the original ones by means of oligonucleotide-directed site-specific mutagenesis and in vitro recombination. Thus, four kinds of chicken lysozyme [Met-1Val31Ser106-, Met-1Ser106-, Met-1Val31- and Met-1 (wild type)] were expressed in E. coli. From the results of folding experiments of the reduced lysozymes by sulfhydryl-disulfide interchange at pH 8.0 and 38 degrees C, followed by the specific activity measurements of the folded enzymes, the following conclusions can be drawn: (i) an extra methionine residue at the NH2-terminus reduces the folding rate but does not affect the lysozyme activity of the folded enzyme; (ii) the substitution of Asn106 by Ser decreases the activity to 58% of that of intact native lysozyme without changing the folding rate; and (iii) the substitution of Ala31 Val prohibits the correct folding of lysozyme. Since the wild type enzyme (Met-1-lysozyme) was activated in vitro without loss of specific activity, the systems described in this study (mutagenesis, overproduction, purification and folding of inactive mutant lysozymes) may be useful in the study of folding pathways, expression of biological activity and stability of lysozyme.

Alanine↗
PubMedDate not supplied

A strategy for the management of elderly women with primary hyperparathyroidism: a comparison of etidronate therapy with parathyroidectomy.

OBJECTIVE: To evaluate the efficacy of etidronate (EHDP) on lumbar spine bone mineral density (LSBMD) and total bone mineral density (TBMD) in elderly women with primary hyperparathyroidism (PHPT), we compared changes in LSBMD and TBMD between patients treated by EHDP therapy and parathyroidectomy (PTX). SUBJECTS AND METHODS: Twenty-two PHPT patients were enrolled and randomized into two groups; 9 received EHDP and 13 underwent PTX. All patients were followed up for 1 year by measuring LSBMD, TBMD, serum calcium, inorganic phosphate, parathyroid hormone, 1,25-dihydroxyvitamin D, serum alkaline phosphatase, intact osteocalcin, urinary pyridinoline (U(pyd)) and urinary deoxypyridinoline (U(dpd)). The presence of spinal fractures was evaluated by X-ray photography before and after treatment. RESULTS: EHDP treatment produced a significant increase in LSBMD of 10% compared with pretreatment levels after 1 year (p < 0.03, compared to baseline), while PTX produced a significant increase in LSBMD of 20% compared to pretreatment levels (p < 0.01). However, TBMD remained unchanged for 1 year after both EHDP administration and PTX. Among biochemical bone turnover markers, EHDP administration resulted in significant decreases in alkaline phosphatase by 78%, U(pyd) by 64% and U(dpd) by 37% after 12 months compared with the pretreatment levels (p < 0.05) and intact osteocalcin by 67% after 6 months (p < 0.05). There were no differences in the fracture rate between the EHDP and PTX groups during 1 year. CONCLUSION: EHDP administration results in a somewhat lower increase in LSBMD than that following PTX and suppresses bone formation and resorption in elderly PHPT patients for 1 year. We conclude that PTX is preferable to EHDP therapy for the management of elderly PHPT patients; however, EHDP administration should also be considered for elderly patients with many complications or who are unfit for surgery.

Aged↗
PubMedDate not supplied

In vivo effects of apoptosis in asthma examined by a murine model.

BACKGROUND: One of the characteristic features of bronchial asthma is the accumulation of various inflammatory cells, predominantly eosinophils, at the subepithelial region beneath the basement membrane of the airway. Apoptosis is a form of physiological cell death, through which the cellular contents including biologically active substances are kept in the cell membrane and are removed without their harmful effects. So, attempts were made to clarify whether the induction of apoptosis is beneficial in asthma by using a murine model with ovalbumin (OA) as responsible allergen. METHODS: A/J mice, which are genetically predisposed to be hyperresponsive to acetylcholine, were immunized with OA and alum, accompanied by OA inhalation for 2 weeks, during which some of the mice were also treated with either anti-Fas monoclonal antibody or sham control hamster IgG intranasally. Airway responsiveness to acetylcholine was then analyzed by measuring airway resistance with a body plethysmograph box. Apoptosis was assessed by propidium iodide and TUNEL staining. RESULTS: Inhalation of OA increased both airway responsiveness to acetylcholine and the number of cells, mostly eosinophils, infiltrated into the airway. Administration of anti-Fas antibody induced apoptosis in the infiltrated eosinophils and abolished augmentation of airway hyperresponsiveness caused by OA inhalation. CONCLUSION: Induction of apoptosis in proinflammatory cells including eosinophils at the airway may have a beneficial effect on suppressing airway hyperresponsiveness.

Acetylcholine↗
PubMedDate not supplied

Small cell carcinoma of the gallbladder: a case report and review of 53 cases in the literature.

Although small cell carcinoma of the gallbladder is rare, the prognosis of this tumor type is poorer than that of differentiated carcinomas. We report herein the case of a 62-year-old man with small cell carcinoma of the gallbladder. The operative findings showed an unresectable large tumor of the gallbladder and multiple metastases involving the liver and lymph nodes. Pathological findings revealed small sized carcinoma cells, round or oval in shape which displayed a cord-like or solid appearance. Diagnosis was confirmed by ultrastructural study that showed the presence of neurosecretory-type cored granules. He was treated by intraarterial chemotherapy with cisplatin and etoposide. Six months later, abdominal computed tomography scan confirmed loss of the large mass. A complete response to the chemotherapy was noted over a period of six months, suggesting the efficacy of intraarterial chemotherapy for this disease. Fifty-three cases of small cell carcinoma reported in the English literature are reviewed. In most cases, including ours, a radical operation was not indicated and the prognosis was extremely poor, due to the difficulty of early diagnosis and the rapid progression of the disease. Chemotherapy is effective in general and intraarterial chemotherapy performed in the present case may be particularly useful to improve survival.

Antineoplastic Combined Chemotherapy Protocols↗