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Biomedical subjects

A Shintani

Publications and source records attributed to A Shintani.

At least 37 records · Page 2Linked to original sources
PubMed1994

Developmental changes of neurotrophin-3 level in the mouse brain detected by a highly sensitive enzyme immunoassay.

Levels of neurotrophin-3 (NT-3) in the mouse brain were measured by a highly sensitive enzyme immunoassay (EIA). The monoclonal antibody, 3W3, was labeled with beta-galactosidase, followed by measurement of galactosidase activity. The detection limit of the EIA system was 0.4 pg/well (4 pg/ml). At 1 and 8 weeks of age, the highest level of NT-3 was detected in the hippocampus, a relatively high level also observed in the cerebellum. In contrast, in the cortex, the striatum, the diencephalon, the midbrain, and the brainstem, NT-3 levels were low. Furthermore, we examined the developmental changes of NT-3 level in the hippocampus and the cerebellum. In the hippocampus, the NT-3 levels were more than 20 ng/g tissue from 1 week to 14 weeks of age, but at 20 weeks of age the level decreased to about half. In the cerebellum, although the NT-3 level was high at 1 week of age, the levels were gradually decreased to one-fourth by 20 weeks of age. In peripheral tissues, a large amount of NT-3 protein was observed in the heart.

Animals↗
PubMed1994

Recombinant human betacellulin. Molecular structure, biological activities, and receptor interaction.

Soluble forms of human betacellulin (BTC) were purified to homogeneity from the conditioned medium of mouse A9 cells transfected with the BTC precursor cDNA. Three types of soluble BTC, designated BTC-1a, BTC-1b and BTC-2, were resolved by cation-exchange and size-exclusion column chromatography. Physicochemical analysis has revealed that BTC-1a represents the glycosylated, intact molecule composed of 80 amino acid residues (Asp32 to Tyr111 of the precursor molecule). BTC-1b appears to be a truncated molecule lacking 12 amino acid residues from the amino terminus of BTC-1a. BTC-2 was found to be a 50-amino acid molecule (Arg62 to Tyr111) that corresponds to the epidermal growth factor (EGF) structural unit. The biological activities of these BTC molecules were essentially identical as judged by their mitogenicity on Balb/c 3T3 fibroblasts. BTC and EGF were equipotent in stimulating Balb/c 3T3 cell proliferation and rat mesangial cell Ca2+ mobilization as well as in inhibiting the growth of human epidermoid carcinoma A431 cells. BTC and EGF antagonized each other with similar dose dependence for binding to A431 cells, indicating that these factors bind the same receptor molecules with equivalent avidity. The Kd value of EGF receptor (EGFR) and BTC is 0.5 nM as determined on Balb/c 3T3 cells. In addition, human mammary carcinoma MDA-MB-453 cells, which express multiple members of the EGFR family, were found to possess 2.7 x 10(3) BTC binding sites/cell, and the binding was readily quenched by EGF. These results suggest that the primary receptor for BTC is EGFR.

3T3 Cells↗
PubMed1994

Purification and characterization of biologically active recombinant human neurotrophin-3 produced by expression of a chimera gene in Chinese hamster ovary cells.

In order to obtain high-level expression of recombinant human neurotrophin-3 (NT-3), we constructed several types of expression plasmids and examined several cell lines for expression of the human NT-3 gene. The highest level production of the recombinant protein was attained in Chinese hamster ovary cells transfected with an expression plasmid that contains a chimera gene encoding the human nerve growth factor (NGF) prepro-region and human NT-3 mature-region under control of a murine leukemia virus-derived long terminal repeat (MuLV-LTR). This cell line can produce more than 1 mg recombinant human NT-3/1 conditioned medium. The recombinant protein was purified to apparent homogeneity with a cation exchange column, a gel filtration column and a reversed-phase HPLC column with a recovery of about 30%. The purified NT-3, at a concentration as low as 0.2 ng/ml, induced neurite out-growth in neurons prepared from 8-day-old chick embryonic dorsal root ganglia; however, it showed little neurotrophic effect on rat PC12 pheochromocytoma cells, which are known to be NGF-responding cells. In addition, this protein promoted colony formation by human peripheral blood lymphocytes in soft agar culture.

Amino Acid Sequence↗
PubMed1993

Monoclonal antibodies against human neurotrophin-3.

Hybridomas producing monoclonal antibodies (MoAbs) against human neurotrophin-3 (hNT-3) were established using recombinant hNT-3 produced in CHO cells and E. coli as immunogens. Of the five MoAbs obtained, MoAb 3w3 showed the highest antibody titer and also best neutralized NT-3 activity as measured by the survival of chick embryonic day-8 dorsal root ganglia neurons. A sandwich enzyme immunoassay (EIA) for NT-3 was established with solid phase MoAb 3W3 and the Fab' fragment of MoAb 3W3 conjugated to horseradish peroxidase. The detection limit was 2.7 pg/well of NT-3 and no cross-reactivity with nerve growth factor up to 100 ng/well was observed. Using this EIA system we have screened a variety of cell lines for NT-3 production. Among these tested, only human Burkitt's lymphoma Namalwa cells were found to be producing NT-3.

Animals↗
PubMed1993

Identification of the functional regulatory region of the neurotrophin-3 gene promoter.

The 5'-flanking region of the human neurotrophin-3 (NT-3) gene was isolated from a human placental genomic library using the oligonucleotide corresponding to the 5'-noncoding region of the NT-3 cDNA as a probe. A 3.8 kbp genomic fragment containing the 5'-flanking region, the first exon and a portion of the first intron was isolated and sequenced. The transcriptional initiation site, identified by S1 nuclease mapping, was located 27 bp downstream from the TATA-like sequence. Several plasmids, in which the NT-3 promoter regions were fused to the chloramphenicol acetyltransferase (CAT) gene, were constructed. Transient expression in human glioma Hs683 cells demonstrated that a fragment of about 0.1 kbp from the transcriptional initiation site was sufficient for promoter activity. While, in human plasma cell leukemia ARH77 cells, in which NT-3 mRNA was not detected, the region upstream from -65 functioned to silence CAT activity. It is suggested that this region contains the transcriptional regulatory element for the specific expression of the NT-3 gene.

Base Sequence↗
PubMed1993

Unusual meningeal tuberculoma--case report.

A 60-year-old male presented with bilateral papilledema. Neuroimaging showed a densely enhanced flat tumor within the interhemispheric region in the frontal and parietal lobes with sulcal obliteration and enhancement. There was no history of tuberculous infection. Histological examination of the excised tissue from the flat tumor within the interhemispheric region was consistent with tuberculoma. Multiple antituberculous agent therapy resolved the papilledema and reduced the tumor.

Diagnosis, Differential↗
PubMed1992

Characterization of the 5'-flanking region of the human brain-derived neurotrophic factor gene.

The 5'-flanking region of the human brain-derived neurotrophic factor (BDNF) gene was isolated from a human placental genomic library using the cDNA fragment for the 5'-noncoding region of human BDNF as a probe. A 3.2 Kbp genomic fragment containing the 5'-flanking region, the first exon and a portion of the first intron was isolated and sequenced. The transcriptional initiation site, identified by S1 nuclease mapping, was located 26 bp downstream from the TATA-like sequence. Several expression plasmids, in which the BDNF promoter regions were fused to the chloramphenicol acetyltransferase (CAT) gene, were constructed. Transient expression in human glioma Hs683 cells demonstrated that a fragment of about 0.5 Kbp from the transcriptional initiation site was sufficient for promoter activity.

Base Sequence↗
PubMed1991

Regional expression of the nerve growth factor gene family in rat brain during development.

The developmental expression patterns of three members (NGF, NGF-2/NT-3, and BDNF) of the NGF family in rat brain are different. NGF-2/NT-3 mRNA was the first detected during development followed by NGF and BDNF mRNAs. A substantial amount of NGF mRNA was found to be synthesized in the hippocampus and the cortex, and this regional expression pattern did not change during development. In contrast, NGF-2/NT-3 mRNA was detected in almost all the brain regions examined in the early developmental stage. In the late stage, the transcript was found in high concentration only in the hippocampus and the cerebellum. BDNF mRNA was widely distributed, and its level was augmented in the late developmental stage.

Animals↗
PubMed1990

Production, purification and characterization of biologically active recombinant human nerve growth factor.

The human NGF gene was isolated and inserted downstream from murine leukemia virus LTR in a plasmid having dihydrofolate reductase cDNA. The expression plasmid was introduced into CHO cells. Selection of the transformants for the resistance to methotrexate gave a CHO cell line which produced human NGF at a level of 4 mg/L in the culture medium. The recombinant human NGF was purified to near homogeneity from the culture supernatant. The NH2-terminal amino acid sequence, the COOH-terminal amino acid (Ala), and the amino acid composition of the human NGF were identical to those deduced from the nucleotide sequence of the human NGF gene. The recombinant human NGF was composed of 120 amino acid residues. Three disulfide linkages were determined to be Cys15-Cys80, Cys-58-Cys108, and Cys68-Cys110; the locations were identical to those in the mouse 2.5S NGF molecule. The specific biological activity of the recombinant human NGF was comparable with that of authentic mouse 2.5S NGF as determined by stimulation of neurite outgrowth from PC12 cells.

Amino Acid Sequence↗
PubMed1988

The percutaneous absorption of propranolol and prediction of the plasma concentration.

In order to avoid first-pass metabolism and to maintain therapeutically effective concentration of propranolol (PL) for a prolonged time, ointments of PL were prepared and the percutaneous (p.c.) absorption was investigated in rabbits. To describe the plasma PL concentration profile during repeated p.c. administrations, a simple pharmacokinetic model, including a first-order absorption process, was applied. The p.c. absorption of PL from both macrogol (400:4000, 30:40, g/g) and Carbopol 934 ointments was significantly increased by adding Azone (AZ). Effective plasma levels were sustained for about 10-20 h, but the absorption of PL from the macrogol ointment was relatively slow. The bioavailability of PL in the 5% PL Carbopol ointment with AZ was 13%. The plasma level of PL after application of Carbopol ointment was enhanced as PL was increased in the ointment, 3 to 5%. The repeated p.c. absorption studies were carried out by applying the 5% PL ointment daily for 3 d. The use of the pharmacokinetic model was justified by good agreement with the observed data after repeated applications of the ointment. Thus, the plasma PL concentration profile during repeated p.c. administrations can be predicted using the model.

Administration, Cutaneous↗
PubMed1985

[Central alveolar hypoventilation as a complication of massive intracerebellar hemorrhage: report of a case treated by diaphragm pacing].

The author reported a case of central alveolar hypoventilation (Ondine's curse) which was treated by diaphragm pacing. A 59-year-old man was admitted because of sudden deep coma and tetraparesis. Neurological examination on admission showed miotic pupils with absent light reaction, no oculocephalic reflex, no corneal reflex and tetraparesis. Glasgow scale was evaluated to be E-1 V-1, and M-3 with total of 5 points. Computed tomography confirmed a large hematoma in the cerebellum with ventricular rupture. Immediately, a suboccipital craniectomy was performed and the hematoma was evacuated. His neurological condition was improved gradually within a month after the operation. He responded to verbal orders and moved all his limbs against gravity. His respiration, however, was irregular with a pattern of so-called "cluster breathing" followed by prolonged apnea, that was more pronounced in night. He was suffered from hypoxic hypercapnea and recurrent pneumonia. Therefore, authors decided to employ diaphragm pacing for management of central alveolar hypoventilation. A diaphragm pacemaker (radiofrequency induction) was implanted. A cuff electrode was put around the right phrenic nerve in the right thorax, and the receiver installed subcutaneously in the right anterior chest. Postoperative respiratory study showed ventilation on pacing with satisfactory blood gas and he became able to move around using a wheel chair. In 1966 Glenn demonstrated a new technique to move the diaphragm paced by a receiver through the phrenic nerve, triggered by radio wave from external device.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebellar Diseases↗
PubMed1984

Kinetics of human pancreatic and salivary alpha-amylases with carboxymethylamyloses as substrates.

The enzymatic measurement of alpha-amylase in human serum with chemically modified amylose as substrate was studied. Several substitutions of carboxymethylamylose were prepared from amylose, suitable amounts of monochloroacetic acid, and sodium hydroxide. The relationship between the degree of substitution of the carboxymethylamylose and the kinetic parameters of human pancreatic, salivary and porcine pancreatic alpha-amylases was determined. The action of alpha-amylases on such modified amyloses in the presence of glucoamylase was measured by a specific enzymatic assay having glucose as the product. The kinetic parameters of human pancreatic alpha-amylase were similar to those of human salivary alpha-amylase. It was possible to determine suitable sensitivities for the alpha-amylase assay using this substrate. These results suggested a subsite model.

Amylose↗
PubMed1982

[Correlation of vasospasm with operative results in ruptured aneurysms].

The present study is a retrospective clinicoradiological correlative investigation of subarachnoid hemorrhage associated with ruptured aneurysms. There were 360 patients in whom the source of subarachnoid hemorrhage was shown by angiography to be a ruptured aneurysm, and 302 of them underwent surgery. Arterial vasospasm was demonstrated in 113 of 360 patients (31%). When the time relationship between the subarachnoid hemorrhage and vasospasm was considered, vasospasms were revealed in 35 patients (31%) to ten days after a hemorrhage. In these cases with preoperative vasospasm, 17 patients were operated within 14 days and 43 patients later than two weeks. On the examination, their clinical state was graded according to Hunt and Hess. The surgical results were also grade in five groups (excellent, good, fair, poor and died) according to the functional results at discharge from the hospital. Of 35 patients of grade I and II at operation, 23 patients (66%) were of excellent or good results. However, of 14 patients of grade IV and V at operation, only on patient took good result. Of 12 patient in whom severe vasospasm was demonstrated and surgery was delayed more than two weeks, 8 patients (66%) had good result. Postoperative vasospasm was recognized in 2 patients, who took poor result. Surgery was carried out in 32 patients on the first or second day after subarachnoid hemorrhage, and 7 patients (22%) of them took good result. The overall mortality was 59% (19 patients). In ten patients, surgery was carried out on the third or fourth day after subarachnoid hemorrhage. Five patients had good result (50%) and four (40%) died. Considering the relationship between the timing and result of surgery, the mortality was 35% in patients operated on in the first week, whereas there were only 38 deaths among the 252 patients operated on after that interval. Among the death patients who were in grade IV or V at admission, intracranial hematoma was seen in 73%. It was concluded that in patients classified as grade I or II, the operation should be performed as soon as possible to prevent another rupture. In grade IV and V patients with severe damage by large hematoma, the mortality and morbidity were high even after evacuation of the hematoma. Patients with marked and diffuse vasospasm should be given conservative treatment at first and then operated on when the patients condition becomes good.

Adult↗
PubMed1979

Microneurosurgery for aneurysms of the basilar artery.

The authors report microsurgical treatment in 32 cases of basilar artery aneurysms, operated on with good results in 28 cases, fair results in one, and poor results in one; there were two deaths. Twenty-nine patients (91%) were able to return to social activities. Characteristics of the surgical techniques include 1) taking a transsylvian route; 2) retracting the M1 portion of the middle cerebral artery (occasionally the C1 portion of the internal carotid) medially with tapered brain retractors; and 3) approaching the aneurysm through and between perforators arising from the posterior cerebral artery in cases of high-placed basilar bifurcation. With regard to instrument improvements, tapered brain retractors, a multipurpose head frame, and bayonet clips (Sugita design) proved very helpful.

Basilar Artery↗