Biomedical subjects

T Kuno

Publications and source records attributed to T Kuno.

At least 91 records · Page 5Linked to original sources

PubMed1993

Detection of the FK506-FKBP-calcineurin complex by a simple binding assay.

[3H]FK506-FK506-binding protein (FKBP) complex does not bind polyethyleneimine-treated glass fiber filters, on the other hand, it binds the filter when it makes a complex with calcineurin. This enabled us to develop a simple binding assay to detect the FK506-FKBP-calcineurin complex in the mixture and to estimate the amount of FKBP or calcineurin which can form the complex in the soluble extracts from rat tissues. The molar concentration of FKBP of every rat tissue is much higher than that of calcineurin, and FKBP/calcineurin molar ratio varies from 13 to 33 in various brain regions, and from 42 to 343 in peripheral tissues. These results suggest that most of the FKBP molecules have physiological roles which are not related to calcineurin, in spite of their potential ability to form the complex with FK506 and calcineurin.

Animals↗

PubMed1993

Down-regulation by retinoic acid of the catalytic subunit of protein phosphatase type 2A during granulocytic differentiation of HL-60 cells.

Activity of protein phosphatase measured in the absence of divalent cations was decreased by 50% during all-trans retinoic acid (ATRA)-induced HL-60 cell differentiation into the granulocytic phenotype. Treatment of HL-60 cells with ATRA led to a dramatic decrease in the amount of protein phosphatase type 2A (PP2A) protein, whereas that of protein phosphatase type 1 (PP1) protein was relatively constant, as detected by immunoblotting with antibodies specific to PP1 and PP2A. The decreased phosphatase activity may be mainly due to a decrease in the expression of the PP2A protein. The mRNA level of PP2A beta was markedly decreased within 5 h after addition of ATRA, but there was only a slight increase in the mRNA level of PP2A alpha. Selective down-regulation of PP2A beta mRNA clearly preceded the cell differentiation induced by ATRA treatment. Thus, PP2A is down-regulated during ATRA-induced differentiation of HL-60 cells into granulocytes.

Cell Differentiation↗

PubMed1993

FKBP12-FK506 complex inhibits phosphatase activity of two mammalian isoforms of calcineurin irrespective of their substrates or activation mechanisms.

The interaction of calcineurin (Ca2+/calmodulin-dependent protein phosphatase) with the potent immunosuppressive agent FK506 and its 12 kDa isoform binding protein (FKBP12) was investigated. The FKBP12-FK506 complex inhibited the Ca2+/calmodulin-stimulated phosphatase activity of each of two calcineurin isoforms, which contain either the catalytic subunit A alpha or A beta (calcineurin A alpha or A beta) of bovine calcineurin. Calcineurin phosphatase activity was inhibited by the FKBP12-FK506 complex irrespective of the substrate or the enzyme activation mechanism. FK506 and FKBP-12 inhibited calcineurin in a concentration-dependent manner, and complete inhibition of the phosphatase activity appeared to require a molar excess of FKBP12-FK506 complex. Immunochemical measurements revealed tissue differences in the concentration of calcineurin, which may be of importance to the selectivity for immunosuppression of all of the biological effects. Direct binding studies with [3H]dihydro-FK506 suggest that the ratio of FKBP12-FK506 complex to calcineurin in vivo when IL2 production is inhibited is well correlated with the ratio when calcineurin phosphatase activity is inhibited in vitro. These results suggest that calcineurin is a relevant cellular target of FK506 when bound to FKBP-12.

Amino Acid Sequence↗

PubMed1993

Molecular cloning of two additional members of the neural visinin-like Ca(2+)-binding protein gene family.

We have isolated a rat cDNA clone encoding a neural visinin-like Ca(2+)-binding protein (NVP), which we designate NVP-1. To identify additional molecular forms of NVP, a rat brain cDNA library was screened for their presence using an NVP-1 cDNA probe under low-stringency hybridization conditions. Two types of cDNA clones encoding structurally related proteins, designated NVP-2 and NVP-3, have been isolated. The deduced amino acid sequences of NVP-2 and NVP-3 are 89.0% and 68.6% identical to that of NVP-1, respectively, and contain consensus sequences for EF-hand Ca(2+)-binding sites. Northern blot analysis shows that NVP-1, NVP-2, and NVP-3 mRNAs are most highly expressed in brain and are differentially expressed in various regions of rat brain. These results suggest that NVP-2 and NVP-3 are additional members of the NVP gene family.

Amino Acid Sequence↗

PubMed1993

How long can continuous ambulatory peritoneal dialysis be continued?

We investigated how long continuous ambulatory peritoneal dialysis (CAPD) could be continued in the face of peritoneal sclerosis. 15 CAPD patients with no experience of peritonitis were selected and the time limitation for CAPD was examined retrospectively, based on the dialysate osmolality, serum creatinine concentration, etc.. The values for the dialysate osmolality and serum creatinine concentration increased gradually with the duration of CAPD and were significantly increased from 6 months. 5 patients whose serum creatinine concentration during the first 6 months after initiation of CAPD increased more than 5 mg/dl, could not continue CAPD for more than 24 months because of the appearance of peritoneal membrane failure. When the time limitation for CAPD was assessed in 10 stable patients, close relationships between the mean dialysate osmolality and duration of CAPD (Y = 0.52X + 351.25, r = 0.83, P < 0.01), and between the mean serum creatinine concentration and duration of CAPD (Y = 0.18X + 6.84, r = 0.95, P < 0.001) were recognized. If the practical limitation for CAPD was set at 400 mOsm/l in terms of the dialysate osmolality or 20 mg/dl in terms of serum creatinine concentration, its value became 94.1 months or 73.1 months, respectively. It is concluded that the time limitation for CAPD can be expected to be approximately 6 to 8 years in stable CAPD patients, and we need to resolve CAPD-induced problems involving the peritoneal membrane in order to continue CAPD for more than 10 years.

Adult↗

PubMed1993

Oral 1,25(OH)2D3 pulse therapy for the treatment of secondary hyperparathyroidism.

We examined the effect of oral 1,25(OH)2D3 pulse therapy in hemodialyzed patients with secondary hyperparthyroidism (2 degrees HPT). Prescription of 6.0 micrograms 1,25(OH)2D3 once a week combined with calcium carbonate as a phosphate binder during the last 5 days a week for 12 weeks resulted in improvement of mild to moderate 2 degrees HPT despite no significant differences in serum total calcium and phosphate concentration. In addition, the effect was greater in cases with mild 2 degrees HPT. A single administration of 6 micrograms 1,25(OH)2D3 reduced the parathyroid hormone concentration in patients with mild 2 degrees HPT or with a short duration of hemodialysis. Tmax of the serum 1,25(OH)2D3 after single administration of 6.0 micrograms 1,25(OH)2D3 was individually different (range, 0.4-20.9 hrs). It is recommended that early employment of oral 1,25(OH)2D3 pulse therapy be undertaken once a week combined with prescription of calcium salt as a phosphate binder during the last 5 days a week for the treatment of 2 degrees HPT refractory to conventional therapy, since there is no risk of aluminum accumulation with satisfactory control of the serum total calcium and phosphate concentration.

Administration, Oral↗

PubMed1993

A case complicated with SLE during maintenance hemodialysis.

A 40-year-old woman suffered from toxemia of pregnancy in 1977 and was admitted to hospital. Thereafter, she developed nephrotic syndrome, underwent a renal biopsy, and a diagnosis of membranoproliferative glomerulonephritis (MPGN) was made. She received steroid therapy, immunosuppressive drug and anticoagulant therapy, and recovered sufficiently to be discharged from hospital in April, 1979. During subsequent ambulatory treatment at our outpatient department, her renal function deteriorated gradually, and maintenance hemodialysis was started from June, 1990. In July, 1991, she was admitted to our hospital with pleurisy and pericarditis. There was no improvement despite antibiotic treatments. Laboratory data revealed leukopenia and lymphopenia. Under suspicion of systemic lupus erythematosus (SLE), relevant tests were carried out. Immunological abnormalities such as positive LE cells and the presence of various autoantibodies, together with clinical signs of hypersensitivity to sunlight, stomatitis and serositis, satisfied the diagnostic criteria of the ARA and a diagnosis of SLE was made. This case did not exhibit any clinical or serological abnormalities except for the renal disorder for a 10-year period after the histological diagnosis of MPGN, but was eventually diagnosed as SLE as a result of the manifestation of SLE symptoms for the first time after one year of maintenance hemodialysis. Immunological abnormalities and SLE during maintenance hemodialysis are discussed in relation to other reports.

Adult↗

PubMed1993

[A case of postoperative pulmonary metastasis of colon cancer which responded to treatment with leucovorin and 5-FU].

A 72-year-old man underwent a radical operation for sigmoid colon cancer (well-differentiated adenocarcinoma, stage III) in 1989. Chest X-ray examination performed in September 1992 showed multiple nodular shadows in the lungs. A diagnosis of pulmonary metastasis was made from abnormally increased CEA and CA 19-9 and findings by chest tomography and CT scanning. There was no evidence of metastasis or recurrence in the liver, bone, brain or large intestine. He received three courses of bolus injections of leucovorin (30 mg/body) and 5-FU (500 mg/body), each over five consecutive days with a two-week rest period, and subsequently weekly at the same doses. CEA and CA 19-9 levels started to decrease after completion of the second course of consecutive treatment. In week 18 of chemotherapy, CEA and CA 19-9 levels dropped to 5.6 ng/ml and 32 U/ml from 66 ng/ml and 130 U/ml, respectively. Chest tomography and chest CT showed the disappearance or reduction in size of the nodules, with a reduction rate of 87.1%. Twenty-two weeks later, at this writing, there was no evidence of disease progression, and the patient was thus judged to be PR. He continues to receive chemotherapy at our outpatient clinic.

Adenocarcinoma↗

PubMed1993

[A case of secondary leukemia induced by chemotherapy with a CDDP-based regimen for gastric cancer 5 years following radical resection].

Cisplatin, mitomycin C and 5-fluorouracil were given a 55-year-old woman for an unresectable gastric cancer, and successful radical gastrectomy was performed. Postoperative adjuvant immunochemotherapy using UFT and PSK was continued for about 4 years and 4 months. Pancytopenia was observed at 5 years after the treatment and then marked leucocytosis was noted. She also showed complications of general fatigue, appetite loss etc. A secondary acute leukemia associated with eosinophilia was diagnosed by peripheral blood examinations, showing WBC, 122,400: blast, 37.5 % and eosinophil, 41%. Results also showed atypia and pseudo-Pelger nuclear abnormality of eosinophil, high positive stain of cell myelogenic cell surface marker, many numeral and structural abnormalities of chromosomal analysis, etc. From the above results, it was suggested that the leukemia might be induced by previously performed chemotherapy. The patient died about 2 months following its onset.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1992

Augmentation of retinoic acid-induced granulocytic differentiation in HL-60 leukemia cells by serine/threonine protein phosphatase inhibitors.

To evaluate the involvement of protein phosphatases (PP) in differentiation of human myelogenous leukemia HL-60 cells, we made use of potent inhibitors of PP1 and PP2A, calyculin-A (CAL-A) and okadaic acid (OKA). CAL-A and OKA could augment all-trans retinoic acid (ATRA)-induced granulocytic differentiation, whereas the differentiation toward macrophage lineage by 12-o-tetradecanoylphorbol acetate (TPA) was unchanged in the presence of CAL-A. CAL-A augmented the phosphorylation of 18K, 23K and 30K proteins induced by ATRA. The PP1 and PP2A were identified and were present mainly in the cytosol of HL-60 cells. These results suggest that either PP1 or PP2A or both may be involved in regulating granulocytic differentiation of HL-60 cells.

Cell Adhesion↗

PubMed1992

Molecular cloning and characterization of the promoter region of the calcineurin A alpha gene.

The 5'-flanking region of the calcineurin A alpha gene was isolated from a rat genomic library. It lacked TATA and CAAT boxes but contained G+C-rich regions, and was demonstrated to function as a strong promoter in neuronal cell lines (NG108-15 mouse neuroblastoma x rat glioma hybrid cells or N1E115 mouse neuroblastoma cells), but not in nonneuronal cell lines (C6 rat glioma or L-M mouse fibroblastoid cells) in a transient chloramphenicol acetyltransferase expression assay. Deletion analysis of the 5'-flanking region revealed that the core promoter region, as well as the sequence critical for cell-type-specific-promoter function, reside within the fragment -107 to +157 with respect to the major transcription initiation site.

Amino Acid Sequence↗

PubMed1992

Ca2+/calmodulin-activated protein phosphatase (PP2B) of Saccharomyces cerevisiae. PP2B activity is not essential for growth.

Protein phosphatase (PP2B) whose activity is stimulated 12-20-fold by Ca2+/calmodulin (CaM) was partially purified by CaM-Sepharose and heparin-agarose chromatographies from cell extract of the yeast Saccharomyces cerevisiae. PP2B activity was not detectable in a mutant in which two genes (CMP1 and CMP2) encoding homologs of mammalian PP2B catalytic subunit were disrupted. We have previously shown that the double gene disruption has no significant effect on the growth of yeast [1991, Mol. Gen. Genet. 227, 52-59]. The results indicated that CMP1 and CMP2 are the only genes that encode the PP2B catalytic polypeptide in S. cerevisiae, and PP2B activity is not essential for the growth of the yeast under normal conditions.

Calcium↗

PubMed1992

cDNA cloning of a neural visinin-like Ca(2+)-binding protein.

A 21,000-dalton Ca(2+)-binding protein (Walsh, M.P., Valentine, K.A., Ngai, P.K., Carruthers, C.A., and Hollengerg, M.D. (1984) Biochem. J. 224, 117-127) was purified from the rat brain and through the use of oligonucleotide probe based on partial amino acid sequence, cDNA clones were obtained from rat brain cDNA library. The complete amino acid sequence deduced from the cDNA contains 191 residues and has a calculated molecular mass of 22,142 daltons. There are three potential Ca(2+)-binding sites like the EF hands in the sequence. It displays striking sequence homology with visinin and recoverin, retina-specific Ca(2+)-binding proteins. Northern blot analysis revealed that the protein is highly and specifically expressed in the brain.

Amino Acid Sequence↗

PubMed1992

The suppression of olfactory bulbectomy-induced muricide by antidepressants and antihistamines via histamine H1 receptor blocking.

The effects of antidepressants [(+)-oxaprotiline, (-)-oxaprotiline, imipramine, maprotiline, and trazodone] and antihistamines (mepyramine, dimethindene, ketotifen, methapyrilene, and antazoline) on muricidal behaviour in olfactory bulbectomized rats were investigated. All drugs except for dimethindene, which only minimally passes across the blood-brain barrier, suppressed muricide. The drugs which have high affinity for histamine H1 receptor showed potent suppressive effect on muricide. It is suggested that the central histaminergic system is involved via H1 receptors in the expression of muricide in olfactory bulbectomized rats.

Aggression↗

PubMed1992

cDNA cloning and tissue distribution of a rat ubiquitin carboxyl-terminal hydrolase PGP9.5.

We have isolated a cDNA clone encoding ubiquitin carboxyl-terminal hydrolase PGP9.5 from a rat brain cDNA library and examined the tissue distribution. The primary structure of the cDNA consists of 856 nucleotides including the entire coding region for 223 amino acids, and the calculated molecular mass is 24,782 Da. The rat PGP9.5 is strikingly homologous to the human PGP9.5, 75.2% of nucleic acids and 95.1% of amino acids being identical. The mRNA of PGP9.5 is most abundant in the rat brain and to a lesser degree in the testis. In other peripheral tissues we tested, the mRNA was undetectable. Western blotting using an anti-rat PGP9.5 antibody revealed the parallel distribution of mRNA and protein in various brain regions and testis. The availability of the rat PGP9.5 clone provides a new approach to examine the function of PGP9.5 and the role that it plays in the pathology of neurodegenerative diseases.

Amino Acid Sequence↗

PubMed1992

Distinct cellular expression of calcineurin A alpha and A beta in rat brain.

Specific polyclonal antibodies that distinguish the two distinct isoforms of the catalytic subunit of calmodulin-dependent protein phosphatase, calcineurin A alpha and A beta, were prepared, and the distribution of calcineurin A alpha and A beta in rat brain was studied using immunochemical and immunocytochemical techniques. Immunochemical measurement revealed that the regional distributions of the two isoforms differed and that A alpha was more abundant than A beta in the rat brain. The subcellular distribution patterns of both isoforms were similar. Both isoforms were highly enriched in cytosolic fractions, including the synaptosomal cytosol. Immunocytochemical analysis revealed that both A alpha and A beta immunoreactivities differed in regional and cellular localizations. These different patterns of expression suggest that the two isoforms of calcineurin A may each have specific functions in modulating neuronal activity in particular cell types.

Animals↗

PubMed1992

Use of two miniplates for intermaxillary skeletal fixation in the treatment of jaw deformity and fracture.

Special techniques of skeletal intermaxillary fixation are described, which may be used in edentulous patients or those with many missing teeth or multiple fractures of the jaw. Two such cases are described in which the usual fixation techniques could not provide sufficient stabilization because of linguoversion and mesioversion or lack of teeth, resulting in inability to maintain a vertical interocclusal relationship. Two long eight-hole Champy miniplates were therefore used distally to the canines on both sides. In the first case, they provided fixation following a sagittal ramus osteotomy to advance the mandible, and in the second case they were used in the treatment of a mandibular fracture.

Adult↗

PubMed1991

cDNA cloning of a calcineurin B homolog in Saccharomyces cerevisiae.

We have isolated a cDNA clone encoding a homolog of mammalian calcineurin B (the regulatory subunit of calmodulin-dependent protein phosphatase) by screening a cDNA expression library of Saccharomyces cerevisiae with antiserum against bovine calcineurin B. The yeast calcineurin B homolog (YCNB) is composed of 175 amino acids with a calculated molecular mass of 19,639 daltons and contains four putative Ca(2+)-binding domains. The amino-acid alignment of YCNB with human calcineurin B demonstrates 53% sequence identity and 82% homology. Southern blot analysis indicates that the gene for YCNB is a single-copy gene. Thus, yeast calmodulin-dependent protein phosphatase apparently has a heterodimeric structure similar to that of the enzyme in mammalians.

Amino Acid Sequence↗