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Biomedical subjects

T Kikuchi

Publications and source records attributed to T Kikuchi.

At least 649 records · Page 36Linked to original sources
PubMed1985

Antidopaminergic effects of bisbenzyl and benzyl tetrahydroisoquinoline alkaloids.

Several bisbenzyl and benzyl tetrahydroisoquinoline (THIQ) alkaloids and bulbocapnine were examined for their abilities to displace 3H-spiperone binding from rat striatal membranes and to antagonize apomorphine-induced rotation in mice with unilateral striatal 6-hydroxydopamine lesions. Receptor binding study showed that bulbocapnine, bisbenzyl and benzyl THIQs exhibited an affinity for dopamine receptors spanning a seven-fold range. In lesioned mice, dauricine, several benzyl THIQs and THIQs antagonized apomorphine-induced rotation. The order of potencies in this test was: dauricine greater than hydrastinine greater than M-9260 greater than demethylcoclaurine, bulbocapnine much greater than cycleanine. In this test, the order of potency did not parallel that in the dopamine receptor binding test. These results suggest that dauricine, THIQs and several benzyl THIQ alkaloids have dopamine receptor blocking activity.

Alkaloids↗
PubMed1985

[A study on the levels of cefoperazone in urological organs].

The concentration of Cefoperazone (CPZ) in urological organs and serum was measured after the intravenous administration of 2 g of CPZ. Serum levels on healthy adults attained a maximal value of 122.1 +/- 4.2 micrograms/ml at 30 minutes. Serum levels of patients operated under general anesthesia attained a maximal value of 159.0 +/- 13.9 micrograms/ml at 30 minutes. Serum concentration on operated cases continued to be 1.3-2.2 fold higher than that of the healthy adults. Prostate tissue levels attained a maximal value of 80.9 +/- 3.6 micrograms/g at 30 minutes, vesical tissue levels were 52.1 +/- 1.3 microgram/g at 60 minutes and renal tissue were 94.0 +/- 14.5 micrograms/g at 90 minutes. Judging from the minimal inhibitory concentration of CPZ, CPZ seemed to be clinically useful in the treatment of urological infections.

Adult↗
PubMed1984

Reconstitution of calpain I and calpain II from their subunits: interchangeability of the light subunits.

Calpain (Ca2 +-dependent cysteine proteinase) is known to be a heterodimer, composed of one heavy (called 80K) and one light (called 30K) subunit. Calpain I, a low-Ca2 +-requiring form from porcine and human erythrocytes, and calpain II, a high-Ca2 +-requiring form from porcine kidney, were separated into their respective 80K and 30K subunits by high-performance liquid chromatography on a TSK-Gel G3000SW column in 1 M NaSCN. The isolated 80K subunits from porcine calpains I and II showed Ca2 +-dependent proteolysis, though much depressed and requiring higher Ca2 + concentrations compared with the respective parent calpains. The optimal conditions were set for the reconstitution of a heterodimeric molecule from the once denatured and separated 80K and 30K subunits. In such reconstitution, the 30K subunits of calpains I and II were found to be functionally identical and interchangeable; either a homologous or heterologous 30K subunit lowered the Ca2 + requirement of an 80K subunit significantly and enhanced the proteolytic activity. Subunit interchange could also be demonstrated between porcine and human calpains.

Animals↗
PubMed1984

Comparative specificity and kinetic studies on porcine calpain I and calpain II with naturally occurring peptides and synthetic fluorogenic substrates.

Homogeneous porcine calpain (Ca2+-dependent cysteine proteinase) was found to hydrolyze a variety of peptides and synthetic substrates. Leu-Trp-Met-Arg-Phe-Ala, eledoisin-related peptide, alpha-neoendorphin, angiotensin I, luteinizing hormone-releasing hormone, neurotensin, dynorphin, glucagon, and oxidized insulin B chain were cleaved with a general preference for a Tyr, Met, or Arg residue in the P1 position preceded by a Leu or Val residue in the P2 position. No great difference in specificity was found between low-Ca2+-requiring calpain I and high-Ca2+-requiring calpain II. 4-Methylcoumaryl-7-amide (MCA) derivatives having a Leu(or Val)-Met(or Tyr)-MCA or a Leu-Lys-MCA sequence were also cleaved by either calpain I or calpain II with preference for Leu over Val by a factor of 9 to 16. Calpains I and II showed similar but not identical kinetic behavior for individual substrates. The Km and kcat values ranged from 0.23 to 7.08 mM and 0.062 to 0.805 s-1 for the calpains, while kcat/Km values for the calpains were only 1/433 to 1/5 of those for papain with a given substrate. With succinyl-Leu-Met(or Tyr)-MCA, calpains I and II were half-maximally activated at 12 and 260 microM Ca2+, respectively, and competitively inhibited by leupeptin (Ki = 0.32 microM for I and 0.43 microM for II) or antipain (Ki = 1.41 microM for I and 1.45 microM for II). Thus, this is the first report describing the specificity and kinetics of calpains I and II.

Amino Acid Sequence↗
PubMed1984

Agonist-specific desensitization of shape change of platelets.

Using scanning electron microscopy and light scattering we have investigated the shape change of bovine platelets. The extents of shape change obtained by ADP and 5-hydroxytryptamine(5HT) increased in dose-dependent manner, and the maximum obtained by these agonists were additive. The agonist-specific desensitization in shape change was observed with ADP, 5HT and thrombin. The extent of desensitization by pre-exposure to ADP was dependent upon the concentration of ADP. It was strongly indicated that receptors or their subsequent stimuli-transmission apparatus became unable to respond to further stimulation after the exposure to the initial stimulation.

Adenosine Diphosphate↗
PubMed1984

Specific desensitization of actin polymerization of bovine platelets.

Polymerization of actin induced by activation of platelets was investigated using deoxyribonuclease I inhibition assay. When platelets were activated with ADP or 5-hydroxytryptamine, actin was polymerized quickly followed by rapid depolymerization to the initial level. Reactivation with the same agonist, however, did not cause the polymerization of actin, though with different agonists actin polymerized quite normally. The mechanism for this agonist-specific desensitization of actin polymerization was investigated by the use of a calcium ionophore A23187. It was suggested that the cause for the desensitization is the inability of platelets to mobilize Ca2+ in response to specific agonist.

Actins↗
PubMed1984

Occurrence of cell division is not exponentially distributed: differences in the generation times of sister cells can be derived from the theory of survival of populations.

The Eyring-Stover survival theory has been applied to the kinetics of the distribution of intermitotic intervals of mammalian cells and by inference to the transition from the G1 phase into DNA synthesis (S phase). The theory faithfully fits experimental data acquired by time-lapse cinemicrography of cloned HeLa cells in tissue culture and also suggests the existence of a labile initiator substance which mediates the G1-S phase transition. This theory provides an alternative to the transition probability model proposed by Smith and Martin [Smith J. A. & Martin, L. (1973) Proc. Natl. Acad. Sci. USA 70, 1263-1267; see also Shields, R. & Smith, J. A. (1977) J. Cell Physiol. 91, 345-355 and Brooks, R. F., Bennett, D. C. & Smith, J. A. (1980) Cell 19, 493-504].

Cell Division↗
PubMed1984

Comparison of tryptic peptides from the heavy and light subunits of calpain I and calpain II by high performance liquid chromatography.

Two different forms of Ca2+-dependent cysteine proteinase, low-Ca2+-requiring calpain I and high-Ca2+-requiring calpain II, are known to be heterodimers, each composed of one heavy (called 80K) and one light (called 30K) subunit. The most probable identity of the 30K and the substantial difference between the 80K subunits of porcine calpains I and II were clearly demonstrated by comparing the tryptic peptide maps obtained upon running a high performance liquid chromatography which permitted parallel detection of tryptophan-containing peptides by fluorometry. Comparison of the amino acid compositions of the two 30K and 80K subunits also confirmed this conclusion. The same chromatographical analysis also revealed close structural similarity of the human calpain I 30K subunit, and even some similarity existing between the calpain I 80K subunits of human and porcine origins.

Amino Acids↗
PubMed1984

Effects on gastric acid secretion of a steroidal alkaloid, epipachysamine-A, extracted from Pachysandra terminalis Sieb. et Zucc.

Effect of a steroidal alkaloid, epipachysamine-A, extracted from Pachysandra terminalis Sieb. et Zucc. on gastric acid secretion was studied in rats. Epipachysamine-A prevented 2-deoxy-D-glucose- or thyrotropin-releasing hormone-stimulated gastric acid secretion in anesthetized rats. However, the compound did not influence bethanechol- or electrical vagal stimulation-induced gastric acid secretion. These results suggest that the effect of epipachysamine-A is due to the influence on the central nervous regulatory mechanism in the gastric acid secretion.

Alkaloids↗
PubMed1984

Large-scale purification of porcine calpain I and calpain II and comparison of proteolytic fragments of their subunits.

Large-scale purification of calpain [Ca2+-dependent cysteine proteinase; EC 3.4.22.17] from porcine tissues is described. The methods used included chromatographies on DEAE-cellulose, Ultrogel AcA 34, Blue Sepharose CL-6B, and DEAE Bio-Gel A which yielded homogeneous enzyme proteins: 27.0 mg of calpain I (low Ca2+-requiring form) from 5 liters of blood with 17,900-fold purification and 57.6 mg of calpain II (high Ca2+-requiring form) from 1.5 kg of kidneys with 5,800-fold purification. Porcine calpains I and II are half-maximally activated at 2.8 microM and 150 microM Ca2+, respectively. They are composed of large and small subunits: Mr 83,000 and 29,000 for calpain I and Mr 80,000 and 29,000 for calpain II. Gel-electrophoretic analysis of the digest with a-chymotrypsin or Staphylococcus aureus V8 protease revealed that the large subunits of calpains I and II are markedly different in structure whereas the small subunits are most likely identical. Mono-specific antibodies directed toward the respective large and small subunits were used for immunoblotting experiments which established not only the identity among several porcine tissues of calpain I but also that of calpain II. several porcine tissues of calpain I but also that of calpain II.

Animals↗
PubMed1984

[Surgical method of retropubic prostatectomy].

The retropubic prostatectomy is performed mostly for prostatic hypertrophy. By performing the preventive suture-ligation of the bilateral prostatic arteries which are running among the vesicoprostatic pedicle before prostatectomy, massive bleeding from bladder neck and prostatic bed can be controlled well, and ligation of bilateral spermatic cord prevents retrograde epididymitis. This surgical procedure makes retropubic prostatectomy easy.

Aged↗
PubMed1984

[clinical studies on primary renal pelvic tumors].

The 15 cases of the primary renal pelvic tumors treated at our Hospital between 1974 and 1983, were reviewed retrospectively. The patients ranged in age from 41 to 74 years old (average: 58.3 years old). There were 11 males and 4 females, the ratio being 2.8:1.0. The affected side was left in 9 cases and right in 6 cases. The most frequent symptom was macrohematuria, which was seen in 12 cases (80%). The major finding of IVP was non-functioning kidney, which was seen in 8 cases (53.3%). Positive urinary cytology was obtained in 8 cases (53.3%). As the surgical method, total nephroureterectomy with bladder cuff was performed in 8 cases, nephroureterectomy in one case and nephrectomy in 6 cases. Histologically, 14 cases were transitional cell carcinoma and one case was squamous cell carcinoma. Simultaneous urothelial tumors were seen in the bladder of 2 patients. A subsequent ureteral tumor was found in one of the 7 cases in which ureters were resected incompletely, and subsequent bladder tumors were found in 8 of the 15 cases receiving surgical treatment in the follow-up period. All of tumors were found within 2 years after operation. Over-all actual survival rates at 1, 3 and 5 years were 87%, 67%, 48%, respectively. Three and 5 year actual survival rates were 100%, 100% respectively for the low stage group and 59%, 29% respectively for the high stage group. Three and 5 year actual survival rates were 100%, 78%, respectively for the low grade group and 44%, 27% respectively for the high grade group. Among several factors, stage and grade of the tumor were the most influencing factors for prognosis.

Adult↗
PubMed1984

[Clinical studies on primary ureteral tumors].

The 15 cases of the primary ureteral tumors treated at our Hospital between 1974 and 1983, were reviewed retrospectively. The incidence of primary ureteral tumors among the outpatients in our urologic clinic was 0.15%. The patients ranged in age from 50 to 75 years old (average: 65.5 years old). There were 11 males and 4 females, the ratio being 2.8:1.0. The right ureter and the lower third of the ureter were involved more frequently than other areas. The most frequent symptom was macrohematuria which was seen in 12 cases (80%). The major finding of IVP was non-functioning kidney, which was seen in 11 cases (73.3). Positive urinary cytology was obtained in 9 cases (60%). Twelve patients underwent nephroureterectomy with bladder cuff or total cystectomy. Histologically, all cases were transitional cell carcinoma. Simultaneous urothelial tumors were seen in the bladder in 4 cases (26.7%). The over-all actual survival rates at 1, 3 and 5 years were 59%, 42%, 42%, respectively. The 5-year actual survival rate was 63% for the low grade group and 0% for the high grade group. The 5-year actual survival rate was 82% for the low stage group and 0% for the high stage group. Among several factors, grade and stage of the tumor were the most influencing factors for prognosis.

Aged↗