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Biomedical subjects

K Hanai

Publications and source records attributed to K Hanai.

At least 55 records · Page 3Linked to original sources
PubMed1987

Platelet proteins, including platelet-derived growth factor, specifically depress a subset of the multiple components of the response elicited by glutathione in Hydra.

Human serum more strongly depressed the feeding response of Hydra (ball formation) elicited by S-methylglutathione than plasma. On the basis of the effect of several proteins released by platelets, at least five apparent components of the response (R1-R5) were suggested. Each of the platelet proteins examined specifically depressed a subset of these components. Among the platelet proteins examined, platelet-derived growth factor (PDGF) specifically depressed the R2 response (the concentration at which the depressing effect was 50% of the maximum [ED50] was 0.17 pM), and basic fibroblast growth factor depressed the R3 and R5 responses (ED50 0.50 aM) and the R2 response (ED50 0.55 pM). With respect to the depression of the R2 response by PDGF, addition of an anti-PDGF IgG or chemical reduction of PDGF, both of which prevent PDGF from binding to its cell surface receptor on responsive cells, eliminated the depressing effect of PDGF on the hydra response. The implications of these observations are discussed.

Animals↗
PubMed1986

Subtotal vertebrectomy and spinal fusion for cervical spondylotic myelopathy.

To perform decompression of the spinal cord and stabilization of the cervical spine in the patients with cervical spondylotic myelopathy, subtotal vertebrectomy and spinal fusion of the cervical spine were carried out in 30 patients. In 18 patients, three vertebrectomies and a spinal fusion were carried out, and in 12 patients, four vertebrectomies and a spinal fusion were carried out. Neurologic symptoms that were present before the operations ranged from transverse lesion type myelopathy to motor system syndrome. The patients' symptoms improved significantly after the operations. By the final consultation, the cervical spine motion reduced by about half in the four level vertebrectomy patients and about one third in the three level vertebrectomy patients. No patients reported cervical pain or pain in the arms.

Adult↗
PubMed1986

Spironolactone therapy for hyperandrogenic anovulatory women--clinical and endocrinological study.

Seventeen patients with irregular menstrual periods and androgenic symptoms such as excessive hair growth, acne, and oily skin were treated with spironolactone. The basal levels of serum testosterone (T), dihydrotestosterone (DHT), estradiol (E2), and luteinizing hormone (LH) were significantly higher in the patients than in the controls. After a 4-week treatment with spironolactone, serum T and DHT showed significant decreases. Before treatment, the serum sex hormone binding globulin (SHBG) levels were significantly lower in the patients than in the controls. After initiation of the spironolactone treatment, the SHBG levels tended to increase but not significantly. Spironolactone treatment resulted in the improvement or disappearance of acne in 4 of 5 patients who suffered from this ailment. Improvement of hirsutism was obtained in 2 of 10 patients. Although 4 oligomenorrheic patients and 6 amenorrheic patients showed anovulatory bleeding but did not ovulate, 2 patients in the amenorrheic group ovulated. Two patients complained of tiredness and weakness, and 2 others of polyuria and polydipsia. Both groups showed only temporary symptoms, so treatment was not interrupted. Spironolactone has beneficial effects on ovarian function and few side effects, so it may prove to be an effective anti-androgen, especially for hyperandrogenic anovulatory patients.

Adult↗
PubMed1982

Anterior decompression for myelopathy resulting from ossification of the posterior longitudinal ligament.

In this series, 15 patients with ossification of the posterior longitudinal ligament underwent anterior decompression to relieve moderate or severe myelopathy, which in 11 included urinary disturbance. The operation consisted of partial resection of the vertebrae, release of the ossified plaque from the surrounding tissue and the insertion of an iliac bone graft. The extent of ossification was confirmed by computerised tomography before and after operation. The plaque was completely detached and moved forward in half of the patients, but only partially moved in the remainder. Symptoms improved considerably. Urinary disturbance disappeared in all patients, but sensory disturbance was left in most. Two patients had prolonged symptoms which were not relieved despite the complete release of the ossified defect.

Adult↗
PubMed1977

Axial transverse tomography of the cervical spine narrowed by ossification of the posterior longitudinal ligament.

Ossification of the posterior longitudinal ligament in the cervical region is generally regarded as a rare disease, though a Japanese series of 185 cases has been reported. The main symptoms arise from a myelopathy, the degree of which varies from moderate to severe, due to stenosis of the spinal canal. In order to clarify the relationship between the severity of symptoms and the cross-sectional area of ossification, axial transverse tomography of the cervical spine has been carried out on twenty-six patients at intervals of 5 millimetres over the full extent of the ossification. In this way the cross-sectional areas of the ossified tissue and of the spinal canal were calculated. The former varied from a minimum of 0.8 to a maximum of 1.8 square centimetres. In cases of severe myelopathy the ossification was mainly at the fourth and fifth cervical levels and the stenosis ration exceeded 30 per cent.

Adult↗
PubMed1976

Potentiometric studies on benzeneboronic acid-alpha-chymotrypsin interactions.

When the competitive inhibitor benzeneboronic acid (BBA) forms a complex with alpha-chymotrypsin [EC 3.4.21.1] protons are released in the acidic pH region. The proton release can be measured by a difference potentiometric technique. The proton release is also observed in chymotrypsinogen A but not in TRCK-, DIP-, and anhydrochymotrypsins. Based on these observations, a simple procedure to estimate the equilibrium constants of the trigonal-tetrahedral interconversion of BBA is proposed. Thermodynamic parameters of the ionization of His 57 and of each step involved in BBA binding can be estimated from the temperature dependence of the proton release. Those of His 57 are essentially the same as those of imidazole in water. Regarding the interconversion of BBA on the enzyme, the value of delta S is similar to delta S not equal to of the deacylation step of nonspecific substrates, and delta H is remarkably reduced from that for the ionization of BBA in water. The enthalpic gain of enzymic process is suggested to be due to the change of the proton acceptor, which is water in the case of the ionization of BBA in water, to imidazole on the enzyme.

Boronic Acids↗
PubMed1976

Temperature-jump studies on the interaction of benzeneboronic acid with chymotrypsinogen.

The interaction of chymotrypsinogen A with benzeneboronic acid (BBA), a transition state along inhibitor of serine proteases, was investigated by the temperature-jump method using pH indicators. It was found that l/tau is dependent on BBA concentration, in contrast to the case of the alpha-chymotrypsin [EC 3.4.21.1]-BBA system in which l/tau is independent of BBA concentration. By examination of the pH dependences of the kinetic parameters, the acid dissociation behavior of His 57 in chymotrypsinogen, chymotrypsinogen-trigonal BBA complex and chymotrypsinogen-tetrahedral BBA complex was analyzed. The kinetic deuterium isotope effect was also examined and found to occur principally on the acid dissociation constants. The state of the catalytic residues in the zymogen molecule is discussed based on these results.

Boronic Acids↗
PubMed1976

Cervical spondylolisthesis.

A case is reported of cervical spondylolisthesis in a 12-year-old girl. The cervical spondylolisthesis has not progressed in the 2 years of observation.

Cervical Vertebrae↗
PubMed1975

Temperature-jump studies on benzeneboronic acid-serine protease interactions. Subtilisin and alpha-chymotrypsin.

The interactions of benzeneboronic acid (BBA) as a transition state analog with subtilisin (EC 3.4.21.4) and with alpha-chymotrypsin (EC 3.4.21.1) were investigated kinetically by the temperature-jump method using pH indicators. For both enzymes, the concentration dependence of the relaxation time was consistent with a two-step mechanism involving a fast bimolecular association followed by a slow, unimolecular process. The possibility of a trigonal-tetrahedral interconversion of BBA at the active site of the enzyme is discussed.

Benzene↗