Biomedical subjects

M Kondo

Publications and source records attributed to M Kondo.

At least 523 records · Page 29Linked to original sources

PubMed1996

cDNA cloning and expression of a gene for isocitrate lyase in pumpkin cotyledons.

A cDNA clone for isocitrate lyase (ICL) was isolated from a cDNA library prepared from the poly(A)+ RNA of etiolated pumpkin cotyledons. The cDNA encoded a polypeptide with 576 amino acids, whose sequence is more than 79% identical to those of ICL from other higher plants and contains the C-terminal tripeptide, Ser-Arg-Met, which is a putative targeting signal to microbodies. Immunogold analysis revealed that ICL protein is exclusively localized in microbodies in etiolated pumpkin cotyledons. Double labeling experiments with protein A-gold particles of different sizes showed that ICL protein coexists with a leaf-peroxisomal enzyme, glycolate oxidase, in the microbodies of greening and senescing pumpkin cotyledons, indicating that transformation between glyoxysomes and leaf peroxisomes occurs directly during greening and senescence of the cotyledons. Immunoblot analysis showed that the amount of ICL protein increased markedly during germination and decreased rapidly when seedlings were exposed to illumination, which induced the microbody transition from glyoxysomes to leaf peroxisomes. In senescing cotyledons, the level of the ICL protein and ICL mRNA increased again with the reverse transition of microbodies from leaf peroxisomes to glyoxysomes. Changes in the amount of ICL protein did not correspond to the changes in the level of ICL mRNA during greening and senescence of the cotyledons, an indication that post-transcriptional regulation plays an important role in the microbody transition.

Amino Acid Sequence↗

PubMed1996

Targeting and processing of a chimeric protein with the N-terminal presequence of the precursor to glyoxysomal citrate synthase.

Glyoxysomal citrate synthase in pumpkin is synthesized as a precursor that has a cleavable presequence at its N-terminal end. To investigate the role of the presequence in the transport of the protein to the microbodies, we generated transgenic Arabidopsis plants that expressed beta-glucuronidase with the N-terminal presequence of the precursor to the glyoxysomal citrate synthase of pumpkin. Immunogold labeling and cell fractionation studies showed that the chimeric protein was transported into microbodies and subsequently was processed. The chimeric protein was transported to functionally different microbodies, such as glyoxysomes, leaf peroxisomes, and unspecialized microbodies. These observations indicated that the transport of glyoxysomal citrate synthase is mediated by its N-terminal presequence and that the transport system is functional in all plant microbodies. Site-directed mutagenesis of the conserved amino acids in the presequence caused abnormal targeting and inhibition of processing of the chimeric protein, suggesting that the conserved amino acids in the presequence are required for recognition of the target or processing.

Amino Acid Sequence↗

PubMed1996

Collagenase gene expression in cutis laxa fibroblasts is upregulated by transcriptional activation of the promoter gene through a 12-0-tetradecanoyl-phorbol-13-acetate (TPA)-responsive element.

Our previous work demonstrated that collagenase mRNA levels are increased in fibroblasts derived from patients with cutis laxa (CL). To pursue the mechanism of the upregulation of collagenase expression, we investigated transcriptional levels of the collagenase gene in CL fibroblasts. Fibroblasts cultured from the skin of three congenital CL patients were studied. Northern blot hybridization revealed 2.8- to 7.3-fold increases in collagenase mRNA levels in CL fibroblasts compared with normal cells. Nuclear run-off experiments demonstrated that the transcription rate of the collagenase gene in nuclei isolated from the same cells was 5.1- to 10.2-fold higher in the CL fibroblasts than in the controls. Transient transfection of a normal collagenase promoter-CAT construct into the cells further showed significantly enhanced transcriptional activity in CL but not in normal fibroblasts. Experiments of transient transfection of deleted or small substituted collagenase promoter-CAT constructs indicated that collagenase transcription in CL fibroblasts was activated the TPA-responsive element site of the collagenase promoter gene. Although the levels of Jun and Fos gene expression did not differ from those observed in normal fibroblasts, AP-1-binding activity, as measured by the ability to bind to an oligonucleotide containing a TPA-responsive element, was significantly elevated in CL fibroblasts as compared with normal fibroblasts. These data suggest that collagenase expression is upregulated at the transcriptional level by endogenous activation of DNA binding of AP-1 in CL fibroblasts [corrected].

Cells, Cultured↗

PubMed1996

Cloning and sequencing of the spore germination gene of Bacillus megaterium ATCC 12872: similarities to the NaH-antiporter gene of Enterococcus hirae.

The germination mutant TM-31 of Bacillus megaterium ATCC 12872, was isolated by transposon Tn917 insertional mutagenesis. Glucose, L-proline, L-leucine and KNO3 germinated TM-31 poorly. The DNA in the region of the Tn917 insertion was cloned, and its nucleotide sequence determined. One major open reading frame was present on the cloned DNA. The hydrophobic protein encoded is presumably membrane-associated. A homology search revealed that the gene encoded in the region of the Tn917 insertion is homologous to napA of Enterococcus hirae. napA codes for the NaH-antiporter. It is hypothesized that transport of cations must play an important role in spore germination in B. megaterium ATCC 12872.

Amino Acid Sequence↗

PubMed1996

Anti-tumor effects of hyperthermia plus granulocyte colony-stimulating factor.

The role of neutrophils in the anti-tumor effects of hyperthermia was investigated in an experimental rat model, and the efficacy of hyperthermia combined with recombinant human granulocyte colony-stimulating factor (G-CSF) was similarly investigated. AH109A carcinoma cells were transplanted into the hind legs of Donryu rats, then heated by a radio-frequency dielectric heater. In this study, because the myeloperoxidase (MPO) activity of neutrophils was not affected by heating or G-CSF, MPO activity was measured as an index of neutrophil migration into tumor tissue. After hyperthermia, MPO activity in tumor tissue increased significantly, suggesting migration of neutrophils into tumor tissue. Depletion of circulating neutrophils by the intraperitoneal injection of anti-rat neutrophil antibody decreased the anti-tumor effects of hyperthermia. Subsequently, we used hyperthermia plus intraarterial G-CSF to enhance the anti-tumor effect. Hyperthermia was induced 1 h after injection of G-CSF, a time when MPO activity in tumor tissue was maximal. A satisfactory thermal effect was noted even in cases where tissue could not be heated sufficiently. In conclusion, neutrophils have an important role in the anti-tumor effects of hyperthermia, and administration of G-CSF enhances these effects.

Animals↗

PubMed1996

Chemical synthesis of phosphorylated peptides of the carboxy-terminal domain of human p53 by a segment condensation method.

A segment condensation method was developed for the chemical synthesis of large (> 90 amino acid) phosphopeptides and was used to produce phosphorylated and non-phosphorylated derivatives of the C-terminal tetramerization and regulatory domains of human p53 (residues 303-393). Efficient condensation synthesis of the 91 residue p53 domain was achieved in two steps. The non-phosphorylated N-terminal segment p53(303-334) (1) and its derivative phosphorylated at serine 315 (1P315), and the non-phosphorylated middle segment p53(335-360) (2), were synthesized as partially protected peptide thioesters in the solid phase using Boc chemistry. The C-terminal segment p53(361-393) (3) and its derivative phosphorylated at serine 392 (3P392) were synthesized as partially protected peptides in the solid phase using Fmoc chemistry. Phosphoamino acid was incorporated into the N-terminal segment (1P315) at the residue corresponding to p53 serine 315 as Boc-Ser(PO3(Bzl)2)-OH during synthesis. Serine 392 in the C-terminal segment was selectively phosphorylated after synthesis by phosphitylation followed by oxidation. A derivative phosphorylated at serine 378 was synthesized in a one-step condensation of the unphosphorylated N-terminal segment (1) and the phosphorylated long C-terminal segment p53(335-393) (2-3P378). Yields of the ligated peptides after removal of the protecting groups and HPLC purification averaged 60% for the first condensation and 35% for the second condensation. All five p53 peptides exhibited monomer-tetramer association as determined by analytical ultracentrifugation. Circular dichroism spectroscopy revealed that phosphorylation at Ser315 increased the alpha-helical content, which was abolished when Ser392 also was phosphorylated, suggesting an interaction between N-terminal and C-terminal residues of the C-terminal domain of p53.

Amino Acid Sequence↗

PubMed1996

Hepatic HCV-RNA as a predictor of outcome after interferon therapy in patients with chronic hepatitis C.

Measurement of serum HCV-RNA is a useful index for evaluating the antiviral effect of interferon therapy in chronic hepatitis C. In the present study, we investigated whether the detection of hepatic HCV-RNA after interferon treatment, using a polymerase chain reaction assay, predicted long-term response to therapy in patients with chronic hepatitis C. Thirty-three patients underwent liver biopsies before and after interferon therapy. Histology and clinical courses were compared after treatment. Before therapy, serum and hepatic HCV-RNA was detected in specimens from 32 (97%) and 33 (100%) patients, respectively. Serum HCV-RNA became undetectable in samples from 22 (67%) patients; however, in 10 of these patients (45%), serum HCV-RNA levels relapsed after therapy. Hepatic HCV-RNA became undetectable in 14 patients after therapy and the serum aminotransferase concentration remained within normal limits during and following (24-92 weeks) therapy in 12 of these patients (86%). All 11 patients with detectable hepatic HCV-RNA also had serum HCV-RNA and elevated aminotransferase concentrations refractory to therapy. The absence of hepatic HCV-RNA at the end of interferon treatment thus predicted a long-term complete response to therapy with a sensitivity of 100%, a specificity of 90% and an accuracy of 94%. We conclude that hepatic rather than serum HCV-RNA is a more useful index for the prediction of the long-term efficacy of interferon therapy.

Adult↗

PubMed1996

Efficacy of ursodeoxycholic acid in combination with interferon-alpha in treating chronic hepatitis C: results of a long-term follow-up trial.

Ursodeoxycholic acid (UDCA) has recently been combined with interferon (IFN) in the treatment of individuals with chronic hepatitis C. However, whether its addition results in a long-term favourable response to IFN remains unclear. A prospective randomized trial of IFN alone versus IFN plus UDCA was therefore undertaken in 52 patients with chronic hepatitis C. All patients received a 24 week course of IFN-alpha (6 x 10(6) U/day for 2 weeks and then three times a week for 22 weeks) and half also received UDCA (600 mg/day) with IFN and then alone for 48 additional weeks. Normalization of serum alanine transaminase (ALT) concentrations at 0, 24 and 48 weeks after cessation of IFN therapy was apparent in 77, 42 and 42% of patients in the IFN-alone group and in 77, 54 and 42% of patients in the IFN plus UDCA group, respectively. There was no significant difference between the two groups with regard to response rate to IFN and the addition of UDCA to IFN treatment had no significant effect on hepatitis C virus (HCV) viraemia. During the follow-up period, 10 of 20 patients with normal serum ALT at the end of IFN treatment relapsed in the IFN-alone group compared with 11 of 20 patients in the IFN plus UDCA group. Among these relapsed patients, serum ALT concentration was significantly lower in the IFN plus UDCA group than in the IFN-alone group during the follow-up period. Twenty-four weeks after cessation of IFN therapy, the percentage of patients with HCV-RNA in their serum who showed a normalization of serum ALT concentrations was significantly higher in the IFN plus UDCA group than in the IFN-alone group (44 vs 6%). Thus, although the addition of UDCA was not associated with a favourable long-term response to HCV viraemia, it did reduce the risk and the severity of relapse following the cessation of IFN therapy.

Alanine Transaminase↗

PubMed1996

A case of Sheehan's syndrome with delirium.

A 53 year old woman was brought to a psychiatric clinic because of delirium. Upon immediate examination, severe hyponatremia (105 mEq/L) was detected. She was suspected of having internal diseases and referred to our university hospital. When she reached our hospital she was delirious and showed excitement and agitation. Her electroencephalogram showed low voltage theta waves (20 microV) in all leads. She was hospitalized and diagnosed with acute tonsillar abscess and panhypopituitarism based on various endocrine tests. Her past history suggested that Sheehan's syndrome had developed after child-bearing at age 31, resulting in panhypopituitarism. After administration of antibiotics, the fever and tonsillar abscess gradually recovered, and the correction of electrolytes improved the level of consciousness, suggesting that the hyponatremia had been closely related to the clouding of consciousness. As the subsequent administration of cortisol kept the patient's serum sodium levels within the normal range, a decrease in plasma cortisol seemed to be the major cause of the hyponatremia. Psychological symptoms of panhypopituitarism often included abulia, apathy and occasionally coma. However, it is rare for a patient with panhypopituitarism to be misdiagnosed as having a psychiatric disease with delirium. This rare case is presented.

Delirium↗

PubMed1996

Cerebral energy metabolism in insulin induced hypoglycemia in newborn piglets: in vivo 31P-nuclear magnetic resonance spectroscopy.

The effect of insulin induced hypoglycemia on cerebral energy metabolism was examined in four newborn piglets. Cerebral energy metabolism was assessed using in vivo 31P-nuclear magnetic resonance spectroscopy. It was demonstrated that the normal level of phosphocreatine/inorganic phosphate (PCr/Pi), an indicator of phosphorylation potential, was maintained at a blood glucose level of 40 mg/dL or above, whereas when blood glucose was reduced to less than 40 mg/dL, PCr/Pi rapidly decreased in parallel with this. Below the critical blood glucose level of 40 mg/dL, a positive correlation (y = 0.02x + 0.632; r = 0.668; P < 0.001) existed between blood glucose and PCr/Pi. In the present investigation, a reduction of blood glucose level to 20 mg/dL or lower resulted in a PCr/Pi of less than 1, indicating a state of cerebral energy failure. The intracellular pH (pHi) was 7.08 +/- 0.05 at the onset and 7.15 +/- 0.07 in the hypoglycemic state, indicating no significant difference between the two groups. The present study has clarified that cerebral energy failure occurs when the blood glucose level is about 20 mg/dL or lower. The critical point of blood glucose exists to maintain brain energy metabolism.

Animals↗

PubMed1996

Biosynthesis of Poly(3-Hydroxyalkanoic Acid) Copolymer from CO(inf2) in Pseudomonas acidophila through Introduction of the DNA Fragment Responsible for Chemolithoautotrophic Growth of Alcaligenes hydrogenophilus.

Pseudomonas acidophila is a bacterial strain producing a poly(3-hydroxyalkanoic acid) (PHA) copolymer from low-molecular-weight organic compounds such as formate and acetate. The genes responsible for PHA production were cloned in cosmid pIK7 containing a 14.8-kb HindIII fragment of P. acidophila DNA. With the aim of developing a means of producing a PHA copolymer from CO(inf2), cosmid pIK7 was introduced into a polymer-negative mutant of the chemolithoautotrophic bacterium Alcaligenes eutrophus PHB(sup-)4. However, the recombinant strain produced a homopolymer of 3-hydroxybutyric acid (polyhydroxybutyric acid) from CO(inf2). Since it was thought that the composition of the accumulated polymer might depend not on the PHA biosynthetic genes but on the metabolism of the host strain, a recombinant plasmid, pFUS, containing the genes for chemolithoautotrophic growth of the hydrogen-oxidizing bacterium A. hydrogenophilus was introduced into P. acidophila by conjugation. The recombinant plasmid pFUS was stably maintained in P. acidophila in the absence of chemolithoautotrophic or antibiotic selection. This pFUS-harboring strain possessed the ability to grow under a gas mixture of H(inf2), O(inf2), and CO(inf2) in a mineral salts medium, and PHA copolymer accumulation was confirmed by nuclear magnetic resonance spectral analysis. A gas chromatogram obtained by gas chromatography-mass spectrometry showed the composition of the polymer to be 52.8% 3-hydroxybutyrate, 41.1% 3-hydroxyoctanoate, and 6.1% 3-hydroxydecanoate. This is the first report of the production of a PHA copolymer from CO(inf2) as sole carbon source.

Journal Article↗

PubMed1996

The interleukin-2 receptor gamma chain: its role in the multiple cytokine receptor complexes and T cell development in XSCID.

Interleukin 2 (IL-2), a T cell-derived cytokine, targets a variety of cells to induce their growth, differentiation, and functional activation. IL-2 inserts signals into the cells through IL-2 receptors expressed on cell surfaces to induce such actions. In humans, the functional IL-2 receptor consists of the subunit complexes of the alpha, beta and gamma chains, or the beta and gamma chains. The third component, the gamma chain, of IL-2 receptor plays a pivotal role in formation of the full-fledged IL-2 receptor, together with the beta chain, the gamma chain participates in increasing the IL-2 binding affinity and intracellular signal transduction. Moreover, the cytokine receptors for at least IL-2, IL-4, IL-7, IL-9, and IL-15 utilize the same gamma chain as an essential subunit. Interestingly, mutations of the gamma chain gene cause human X-linked severe combined immunodeficiency (XSCID) characterized by a complete or profound T cell defect. Among the cytokines sharing the gamma chain, at least IL-7 is essentially involved in early T cell development in the mouse organ culture system. The molecular identification of the gamma chain brought a grasp of the structures and functions of the cytokine receptor and an in-depth understanding of the cause of human XSCID. To investigate the mechanism of XSCID and development of gene therapy for XSCID, knockout mice for the gamma chain gene were produced that showed similar but not exactly the same phenotypes as human XSCID.

Animals↗

PubMed1996

Diabetic renal failure and serum accumulation of the creatinine oxidative metabolites creatol and methylguanidine.

Diabetic patients (n = 23) with chronic renal failure (CRF) accumulate the creatinine (Cr) oxidative metabolites creatol (CTL) and methylguanidine (MG; a uremic toxin) in their sera. Analysis of serum CTL, a key intermediate in mammalian Cr catabolism into MG, is shown to offer some useful diagnostic information on CRF, especially in the determination of an initial stage of pathological renal failure. The sera of all diabetic (n = 23) and nondiabetic (n = 20) patients with CRF (s-Cr > 1.25 mg/dl) contained s-CTL (> 2 micrograms/dl), whereas those from normal subjects (n = 18) and diabetic patients (n = 18) without CRF contained no detectable s-CTL. A similar accumulation of s-MG was observed, but only when s-Cr was higher than 2.0 mg/dl. Although each s-CTL (Y: microgram/dl, Y': mol/l) and s-MG level (Z: microgram/dl, Z': mol/l) is highly correlated with s-Cr (X: mg/dl, X': mol/l) in a normal equation, Y or Z = AX + B, an alternative correlation in a second-order equation, Y or Z = alpha X2 + beta X, could also fit well. Since the quadratic equation can be convertible to Y/X or Z/X = alpha X + beta [Y'/X' or Z'/X' = alpha' X+ beta'] and active oxygen species, especially hydroxyl radicals, convert Cr into CTL, Y/X, Y'/X', Z/X and Z'/X' values which might be a kind of indices for oxygen stress (oxidative stress) increased in proportion to the increased severity of CRF in such patients. Although its meaning and interpretation are still debatable, diabetic CRF patients had a significantly higher alpha' value (2.2) than that (0.89) of nondiabetic CRF patients. All serum values for Cr, CTL and MG were measured with HPLC.

Creatinine↗

PubMed1996

Synthesis and biological activity of the metabolites of diethyl 4-[(4-bromo-2-cyanophenyl)carbamoyl]benzylphosphonate (NO-1886).

Five metabolites of diethyl 4-[(4-bromo-2-cyanophenyl)carbamoyl]benzylphosphonate (NO-1886) (1) were synthesized to confirm their proposed structures. The metabolites (2-6) were found to be identical with the synthesized compounds. These metabolites were orally administered to Triton WR-1339-induced hypertriglyceridemic rats, and the plasma levels of triglycerides were measured to estimate lipoprotein lipase activity. All the metabolites showed lower potency than NO-1886.

Animals↗

PubMed1996

Noradrenergic hyperinnervation in the heart of stroke-prone spontaneously hypertensive rats (SHRSP).

Noradrenergic (NA) nerve fiber density was investigated in the subepicardium and myocardium of ventricles in stroke-prone spontaneously hypertensive rats (SHRSP) and was compared with that of normotensive Wistar Kyoto (WKY) rats. Fluorescent NA nerve fibers in the subepicardium of the right and left ventricles of both strains at the ages of 10, 30, 60, 90, and 180 days were examined by the glyoxylic acid method. NA nerve fibers in the myocardium of the right and left ventricles and the ventricular septum of both strains at the ages of 30, 90, and 180 days were also examined in a similar manner. The density of NA nerve fibers was measured by quantitative image analysis. The distribution pattern of NA nerve fibers in the entire subepicardium of ventricles of both strains showed a meshwork pattern throughout the examination period. In sections of the myocardium, NA nerve fibers were distributed between heart muscle cells and around blood vessels in both strains at all ages examined. The densities of NA nerve fibers in the subepicardium of the ventricles of SHRSP were significantly higher than those of WKY rats at all ages examined except for the subepicardium of the left ventricle at 90 days of age. The densities in the myocardium of the right ventricle in 30- and 90-day-old SHRSP were significantly higher than those in WKY rats. The ratios of NA nerve fiber density of SHRSP to that of WKY rats were greater in the subepicardium of the right and left ventricles, except at 90 days of age, and in the myocardium of the right ventricle of younger animals as compared with older ones. NA hyperinnervation in the subepicardium and myocardium of the ventricles of SHRSP may be a primary change of the heart before the onset of hypertension and may be caused by hyperfunction of the stellate ganglia.

Adrenergic Fibers↗

PubMed1996

Longitudinal distribution of pulmonary vascular compliance in dogs.

The longitudinal distribution of pulmonary vascular compliance was evaluated in isolated canine lung lobes using arterial-(AO), venous-(VO), and double-occlusion (DO) techniques. Total vascular compliance (Ctau) was separated into pulmonary arterial (Ca) and venous compliance (Cv) in lumped model of pulmonary circulation. Under constant pulmonary venous pressure (Pv) at 5 mmHg, blood inflow to the lobe (Q) was gradually increased by changing pulmonary arterial pressure (Pa) from 10 to 22 mmHg at 4 mmHg ranges. Changes in vascular blood volume (deltaV) with each increment in Q were determined by decreased reservoir blood volume of perfusion system. DO was performed at each level of Q and allowing all vascular pressures to equilibrate at the same static pressure (Ps), which was equal to the compliance-weighted average pressure in the circulation. Ctau was obtained from the slope of the relationship between Ps and deltaV. When Pa and Pv were 14 and 5 mmHg, AO, VO, and DO were performed to measure pressures at Ca (Pca) and Cv (Pcv) and Ps. The arterial-to-venous compliance ratio (Ca/Cv) was evaluated using Pca, Pcv, and Ps measurements. Ctau was 0.113 +/- 0.012 ml/kg/mmHg. Ca/Cv was 0.30. Ca and Cv were 0.026 +/- 0.013 and 0.087 +/- 0.007 ml/kg/mmHg, respectively. These data demonstrated the usefulness of AO, VO, and DO techniques in evaluating the longitudinal distribution of compliance in canine pulmonary vasculature.

Animals↗

PubMed1996

Nephrogenic diabetes insipidus induced by lobenzarit disodium treatment in patients with rheumatoid arthritis.

Nephrogenic diabetes insipidus (NDI) occurred in a 43-year-old woman who had received lobenzarit disodium for the treatment of rheumatoid arthritis (RA). Her urine output was initially 3 l/day and urine osmolarity was 203 mOsm/l. Based on a sodium chloride loading test and a vasopressin loading test, she was diagnosed as having lobenzarit-induced NDI. Seven days after the cessation of the use of lobenzarit disodium, polydipsia and polyuria disappeared, and the vasopressin test showed a normal response. These findings suggest that lobenzarit induces a reversible form of NDI as a side effect. The reports of lobenzarit-induced NDI in Japan during the past seven years are also reviewed.

Adult↗

PubMed1996

Cimetidine in the treatment of porphyria cutanea tarda.

The efficacy of the H2 receptor antagonist, cimetidine, in the treatment of a patient with porphyria cutanea tarda (PCT) was evaluated. After administration of cimetidine for 2 weeks, urinary excretion of uroporphyrin (UP) and coproporphyrin (CP) was significantly decreased. Urinary porphyrin levels remained low even after the cessation of cimetidine for 1 week. Although the readministration of cimetidine did not decrease porphyrin excretion, skin lesions were markedly improved, and serum gamma-glutamyl transpeptidase (GGT), aminotransferases and serum ferritin decreased to the normal range. These results suggest that, in addition to efficacy in the treatment of acute intermittent porphyria (AIP) and erythropoietic protoporphyria (EPP), cimetidine is effective in the treatment of PCT.

Cimetidine↗