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Biomedical subjects

T Sakurai

Publications and source records attributed to T Sakurai.

At least 451 records · Page 25Linked to original sources
PubMed1993

Homogeneous production of feline interferon in silkworm by replacing single amino acid code in signal peptide region in recombinant baculovirus and characterization of the product.

In a previous paper we reported that we constructed a recombinant baculovirus named BmFeIFN1 which produced recombinant feline interferon (FeIFN) in silkworm after infection. High purification of FeIFN in body fluid from the larvae revealed that two kinds of FeIFN were produced by the BmFeIFN1. The difference between the two in the NH2-terminal amino acid sequence was clarified, and two kinds of processing at different sites in FeIFN precursor were suggested. Changing one residue of the amino acid sequence in deduced signal peptide by site directed mutagenesis of encoding cDNA led to the production of homogeneous FeIFN whose NH2-terminal three amino acid sequence was identical to the conserved sequence of human interferon-alpha. We designated the FeIFN produced as rFeIFN. Amino acid sequence analysis revealed that rFeIFN consisted of 170 amino acid residues. The COOH-terminal amino acid of the rFeIFN is Glu which is located at one amino acid residue upstream to the COOH-terminal amino acid deduced from the nucleotide sequence. Positive periodic acid Schiff reaction, undetectability of Asn at position 79 by automated protein sequencer, and detectability of N-acetylglucosamine not N-acetylgalactosamine suggested that rFeIFN was N-glycosylated. rFeIFN was stable at pH 1.5 at 4 degrees C for at least 50 days, and had an antiviral action on feline calicivirus or feline herpesvirus in vitro. Its isoelectric point was pI 6.5. Comparing the structure and biosynthesis of rFeIFN with those of HuIFNs, rFeIFN may be classified as omega-type.

Amino Acid Sequence↗
PubMed1993

Cryopreservation of expanded mouse blastocysts by vitrification in ethylene glycol-based solutions.

Experiments were conducted to find optimal conditions for obtaining high survival of expanded mouse blastocysts after vitrification. The vitrification solutions used were designated EFS20, EFS30 and EFS40, and contained 20%, 30% and 40% ethylene glycol, respectively, diluted in PB1 medium containing 30% Ficoll plus 0.5 mol sucrose l-1. In the toxicity test of the solutions and each cryoprotectant, ethylene glycol was found to be toxic to embryos. For vitrification, expanded blastocysts were exposed to the vitrification solutions at 10, 20 or 25 degrees C for various periods; they were then cooled rapidly in liquid nitrogen, after which they were warmed rapidly. When the embryos were directly exposed to EFS40 at 20 degrees C for 2 min before vitrification, 66% of them re-expanded during 48 h of post-warming culture. The re-expansion rates decreased when exposure time was shortened (0.5 min), when exposure temperature was lowered (10 degrees C), or when embryos were vitrified in EFS20 and EFS30, although these conditions should be less toxic. When embryos had been pretreated in a dilute (10-20%) ethylene glycol solution for 5 min, followed by short exposure (0.5 min) to EFS40 at 20 degrees C, post-vitrification survival rate increased to 83-84%; furthermore, the rate reached 94% when the temperature was increased to 25 degrees C. Expanded blastocysts cryopreserved by this two-step method developed into live young as well as control embryos after transfer.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Desmoplastic infantile ganglioglioma with extraparenchymatous cyst--case report.

A large supratentorial tumor associated with an extraparenchymatous cyst and multiloculated intraparenchymatous cysts occurred in a 14-month-old infant. This case had all the characteristic features of desmoplastic infantile ganglioglioma both clinically and histologically. The notable difference was the extraparenchymatous cyst. The extraparenchymatous cyst was probably caused by entrapment of cerebrospinal fluid in the subarachnoid space by some check-valve mechanism because the leptomeninges were commonly involved in the tumor. A similar mechanism may explain the etiology of the intraparenchymatous, disproportionately large cyst in desmoplastic infantile gangliogliomas.

Biomarkers, Tumor↗
PubMed1993

Deoxypyrimidine cluster mediates the priming by calf thymus DNA primase subunit.

Homogeneously purified DNA polymerase alpha subunit-free primase was used to analyze primer RNA synthesis. On a chemically synthesized 36 mer DNA template, a part of upstream region of human c-myc gene, the primer synthesis started from a doublet of deoxythymidine (TT) in the deoxypyrimidine-rich sequence. The primase in DNA polymerase alpha-primase complex synthesized 21-mer reaction product, while DNA polymerase alpha-free primase gave the similar products, 21- and 22-mer, indicating that the site recognition was carried out by primase itself and DNA polymerase alpha subunit has an auxiliary role on it. Product analysis using DNA fragments carrying base substitutions further revealed that the existence of deoxypyrimidine residues around the starting sites was important for priming frequencies. Competition analysis showed that the priming was strongly competed by poly(dC), and to a much lesser extent by poly(dA). Gel-shift analysis showed that the primase could bind to the DNA template, and this complex formation was also competed by poly(dC), but not by poly(dA). These results indicate that primase subunit interacts with the starting site by binding directly with deoxypyrimidine residues.

Animals↗
PubMed1993

Below-elbow joint arterial reconstruction for chronic ischaemia.

Ten below-elbow joint arterial bypass grafts performed in nine patients for chronic upper extremity ischaemia are reviewed. The cause of the ischaemia was thromboangiitis obliterans in four patients, iatrogenic trauma in four and unknown aetiology in one. Graft revision was required in two patients with thromboangiitis obliterans who underwent axillary-brachial bypass. Eight grafts, including one reoperation, have remained patent from 1 to 10 years (mean 54.3 months). Graft failure after 5 months did not occur, at which time the primary patency rate was 80%. In general, the long-term patency rates of autogenous vein bypass graft to the forearm were satisfactory. Aggressive arterial reconstruction is especially indicated in significant chronic upper extremity ischaemia resulting from iatrogenic trauma, as chances of success are excellent. Clinical and technical problems of in situ vein bypass in the upper extremity are discussed.

Adult↗
PubMed1993

[A case of gliosarcoma associated with large cyst].

A case of gliosarcoma with a large cyst is reported. A 22-year-old female was admitted to our hospital with complaints of blurred vision and headache. Plain skull x-ray films showed a radiolucent area in the right frontal area. Computed tomography (CT) revealed an iso-dense mass in the right frontal lobe with a large cyst. After administration of contrast medium, the solid part and cyst wall were well enhanced and the content of the cyst was slightly enhanced. CT number of the cyst fluid was increased from 64.2 to 83.5 Hounsfield units, after administration of the contrast medium. Axial T1-weighted magnetic resonance image (MRI) revealed an iso-intense mass with marked enhancement by Gd-DTPA in the same area. A large cyst was shown to be located in the dorsal part of the mass. A small round protrusion, 10 mm in diameter, was found on the anterior portion of the mass on this MRI. Right carotid angiogram showed a tumor stain fed by the frontopolar artery. Right frontal lobectomy including the tumor was carried out with a preoperative diagnosis of glioblastoma. The patient received radiation therapy of 60Gy (whole brain 40Gy; focal 20Gy) and chemotherapy postoperatively. Histologically, necrosis, hemorrhage and endothelial hyperplasia were revealed at the tumor lesion. The tumor was composed of proliferation of glial and mesenchymal elements. The glial element appeared as fibrillary astrocytoma and polar spongioblastoma. The mesenchymal element showed sarcoma. As mentioned above, this tumor was diagnosed as gliosarcoma. It was difficult to make a diagnosis of gliosarcoma preoperatively because of the complex findings similar to malignant gliomas in conventional neuroradiological imaging.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Hemofiltration for the treatment of patients with congestive heart failure].

Hemofiltration is usually performed to patients with renal failure but is also an effective method for treating patients with congestive heart failure due to various causes such as hypotension, low cardiac output, oliguria and anasarca. By continuing 24hr a day at low blood flow rate, CAVH (Continuous Arteriovenous Hemofiltration) or CVVH (Continuous Venousvenous Hemofiltration) can remove the body fluid up to 500 ml/hr without much affecting systemic circulation. Successive management of body fluid even results in the recover of renal insufficiency due to decreased renal blood flow or drug overload. To perform hemofiltration safely, it is important to monitor the systemic circulation. Usually we monitor the diameter of IVC (Inferior vena cava) with ultrasonography thought the procedure the to detect changes in blood volume simultaneously.

Anticoagulants↗
PubMed1993

[Detection of obscure fistulas complicated with Crohn's disease by indocyanine green].

When treating patients with Crohn's disease (CD), external or internal fistulas connected to the intestine were encountered, and these were often difficult to diagnose correctly. In order to diagnose such fine fistulas, we modified a method of using indocyanine green (ICG) administration to the gut lumen. The subjects of this study comprised nine patients with CD who had an obscure fistula which could not be demonstrated by barium study, fistulography, or by urological or gynecological examinations. If the administrated ICG was detected by various ways from an external fistula or from the neighboring organs, a fistulous connection was thought to be evident. Following oral administration in nine patients, colonic fistulas became evident in seven and by ICG enema in three patients, colonic fistulas became evident in all three. In addition, since the fistulous connection was ameliorated following nutritional therapy, it would appear that ICG administration is a useful marker of such therapy for this condition. ICG administration was therefore thought to be a useful method of detecting obscure fistulas connected to the intestine.

Adult↗
PubMed1993

DNA helicases associated with DNA polymerases from human cells.

A crude DNA polymerase fraction partially purified from a low salt extract of HeLa cells was fractionated on a hydroxylapatite column by an elution with a linear gradient of potassium phosphate. By this procedure, DNA polymerase alpha, delta and epsilon were separated from each other. DNA helicase activities were detected in the DNA polymerase alpha and delta fractions but not in the epsilon fraction. Characterization of DNA helicases after further purification on heparin column revealed that the DNA helicase in the DNA polymerase alpha fraction required ATP (or dCTP) in addition to ATP (or dATP). Both DNA helicases translocated on single-stranded DNA in the same direction of 3' to 5'. By a repeated gel-filtration on Superose 6 (SMART system), activities of DNA polymerase alpha and delta were eluted at positions of approx. 600 kDa and 400 kDa, respectively, and the activities of DNA helicases were well associated with those of corresponding DNA polymerases. These results strongly suggest that the DNA helicases described here are physically associated with DNA polymerase alpha and delta to make large complexes.

Animals↗
PubMed1993

[Argyrosis of the urinary tract after silver nitrate instillation: report of a case].

A 69-year-old woman was referred to our hospital for evaluation of pyuria and renal dysfunction. Twenty days earlier, the patient had undergone silver nitrate retrograde instillations for essential renal bleeding. Routine laboratory findings showed renal dysfunction with a serum creatinine concentration of 7.2 mg/dl and blood urea nitrogen concentration of 68 mg/dl. The urine contained numerous red cells and white cells. The plain X-ray film of the abdomen revealed right renal calcification. Computed tomographic scan confirmed the calcifications in the right renal collecting systems and parenchyma. The most likely diagnosis was argyrosis of the upper urinary tract. The patient underwent a right nephrectomy. Histopathological examination of the specimen showed that the renal pelvis was filled with blood clots. Laboratory evaluation including serum creatinine concentration and urinalysis revealed normal parameters postoperatively. We conclude that this patient developed argyrosis of the urinary tract, and review previously published papers concerning complications of silver nitrate instillation.

Administration, Intravesical↗
PubMed1993

[The long-term follow-up study of Japanese patients with ulcerative colitis].

To elucidate the long-term outcome of the ulcerative colitis we analyzed 124 patients suffering for more than 10 years concerning the long-term prognosis, cumulative rate of colectomy, cumulative risk of cancer development and cumulative survival rate. Long-term prognosis were divided to three categories as good, fair and poor, according to present disease activities, social availability and subjective judgement. One hundred and twenty four patients were divided to 66 patients with good prognosis, 27 fair and 31 poor (2:1:1). The rate of patients having active disease at each year were followed-up annually for 10 years according to final three categories of the prognosis. The serial curve of annual rate of having active disease of the patients with poor prognosis was the highest, fair prognosis the second, good prognosis the lowest. The factors affecting the final prognosis were the period before initiation of proper treatment, the severity of the first attack or the elder age (> 40 year old) at the first attack. Twenty six patients were undergone colectomy in relation to ulcerative colitis. The cumulative colectomy rate was 16.5% at 10 years and 38.5% at 15 years after the onset. Malignant disease or severe dysplasia of the colon developed in 4 patients 10 to 14 years after the onset. Cumulative survival rate was equal to the expected survival curve during 16 years. The main causes of death were intracranial hemorrhage and colorectal malignant disease.

Adolescent↗
PubMed1993

[An efficient method for quantification of Helicobacter pylori in biopsy specimen using PCR].

A procedure for the detection and quantification of Helicobacter pylori in gastrointestinal tissue biopsy specimens by polymerase chain reaction (PCR) is presented. This method provides an accurate quantitative and sensitive measurement of the amount of H. pylori in the gastrointestinal tract without cultivation of this microorganism. We have used 30 cycles of PCR in the presence of 3.5mM Mg++ and demonstrated that the DNA content of one H. pylori cell is 0.0076pg. Using this approach, we analyzed samples of gastrointestinal tissue biopsies from 10 patients with various gastrointestinal disorder. Each of these patients had detectable H. pylori at levels ranging from 0.10 to 60.61 cells for each tissue cell. This new technique thus provides a useful way to detect H. pylori in gastrointestinal tissue biopsy specimens.

Adult↗
PubMed1992

[Prospective randomized trials comparing hyperfractionated radiotherapy with conventional radiotherapy in stage III non-small cell lung cancer].

From September 1987 to August 1990, 36 patients with stage III non-small cell lung cancer were randomly assigned to 65 Gy in 26 fractions of 2.5 Gy each (conventional radiotherapy) or 71.5 Gy in 52 fractions of 1.375 Gy given twice a day (hyperfractionated radiotherapy). The overall time for both groups was 6.5 weeks. The groups were similar in terms of age, performance status, previous chemotherapy, stage IIIA and IIIB, and histopathology. The rate of complete response was 44.4% for hyperfractionation, and 16.7% for conventional fractionation. Overall survival rates at 24 months and 36 months were 50.0% and 21.8% for hyperfractionation, and 31.3% and 0% for conventional fractionation. Fever due to radiation pneumonitis occurred in seven of 18 patients with hyperfractionation (38.9%) and four patients with conventional fractionation (22.2%). No severe late toxicity has been observed in either group. We conclude that hyperfractionated radiotherapy in non-small cell lung cancer may improve survival without increasing severe toxicity.

Adult↗
PubMed1992

Kinetics of electron transfer between cytochrome c and laccase.

Rate constants have been determined for the electron-transfer reactions between reduced horse heart cytochrome c and resting Rhus vernicifera laccase as a function of pH, ionic strength, and temperature. The second-order rate constant for the oxidation of reduced cytochrome c was determined to be k = 125 M-1 s-1 at 25 degrees C in 0.2 M phosphate buffer at pH 6.0 with the activation parameters delta H++ = 16.2 kJ mol-1 and delta S++ = 28.9 J mol-1 K-1. The rate constants increased with decreasing buffer concentration, indicating that electron transfer from cytochrome c to laccase is favored by the local electrostatic interaction (ZAZB = -0.9 at pH 6 and -1.3 at pH 4.8) between the basic proteins with positive net charges. From the increase of the rate of electron transfer with decreasing pH, one of the driving forces of the reaction was suggested to be the difference in the redox potentials between the type 1 copper in laccase and the central iron in cytochrome c. Further, on addition of one hexametaphosphate anion per cytochrome c molecule, the rate of the electron transfer was increased, probably because the association of both proteins became more favorable.

Animals↗
PubMed1992

Complete primary structure and tissue expression of chicken pectoralis M-protein.

M-Protein (165 kDa) is a structural constituent of myofibrillar M-band in striated muscle. We generated a monoclonal antibody which recognized a 165-kDa protein from chicken pectoralis muscle in immunoblot analysis and stained the M-band under immunofluorescence microscopy. By screening a lambda gt11 cDNA library from chicken embryonic pectoralis muscle with this antibody, we isolated a cDNA clone encoding the M-protein. Northern blot analysis showed that M-protein mRNA is expressed in pectoralis and cardiac muscle but not in gizzard smooth muscle or non-muscle tissues. Moreover, the anterior latissimus dorsi muscle, which consists almost exclusively of slow fiber types, contains no detectable levels of the mRNA. The full-length cDNA sequence predicted a 1,450-amino acid polypeptide with a calculated molecular weight of 163 x 10(3). The encoded protein contains several copies of two different repetitive motifs: five copies of fibronectin type III repeats are in the middle part of the predicted molecule, and two and four copies of the immunoglobulin C2-type repeats are located toward the NH2-terminal and COOH-terminal regions, respectively. This indicates that M-protein, along with other thick filament-associated proteins such as C-protein, twichin, and titin, belongs to the superfamily of cytoskeletal proteins with immunoglobulin/fibronectin repeats.

Amino Acid Sequence↗
PubMed1992

Efficient purification of a full length and biochemically active p110Rb, the retinoblastoma gene product.

Rb protein was purified from recombinant baculovirus-infected Sf9 cells to apparent homogeneity by a simple solubilization and by immunoaffinity column chromatography. It was mainly obtained as p110Rb, the underphosphorylated form of the Rb protein family. This p110Rb was shown to form a specific complex in vitro with SV40 Tag and to bind to double or single stranded DNA. It could also affect Tag helicase activity in a biphasic-dose dependent manner, due to these two biochemical functions. This purification procedure provides sufficient amounts of native Rb protein to further elucidate its role as an anti-oncogene protein and a negative regulator of the cell cycle.

Animals↗