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Biomedical subjects

A Nagata

Publications and source records attributed to A Nagata.

At least 55 records · Page 3Linked to original sources
PubMed1998

Case report: Steatonecrosis in the upper abdomen following transcatheter arterial embolization for hepatocellular carcinoma.

A 66-year-old female with liver cirrhosis was treated by transcatheter arterial embolization (TAE) for a small hepatocellular carcinoma. She developed steatonecrosis with tenderness which occurred in the upper abdomen after TAE. The hepatic falciform artery from the middle hepatic artery was detected by arteriography. Necrosis in the upper abdomen was considered to be due to ischaemic changes caused by micromaterials for embolization of this artery, injuries of hepatic arterial endothelia slowly caused by carcinostatics, and chemotoxicity. It was considered that such complication as observed in this patient should be taken into consideration when performing TAE.

Aged↗
PubMed1998

Afterdischarges following F waves observed in a patient with tetanus.

We report a case of non-fluminent and mildly affected tetanus patient who showed afterdischarges following F waves in the affected extremity. The afterdischarges occurred following F waves and showed different configuration respond to each stimuli. Diazepam was also effective for spasms of our patient. This finding disappeared after treatment and showed a good correlation to clinical symptoms. These observations suggest that afterdischarges following F waves are induced by tetanus toxin which puts most of the motor neuron pool in a hyperactive state through its own action to the motor nerve including the spinal motor neuron.

Action Potentials↗
PubMed1997

Enzyme-linked immunosorbent assay using F(ab')2 fragment for the detection of human pulmonary surfactant protein D in sera.

We developed an enzyme-linked immunosorbent assay (ELISA) for detection of SP-D in serum using recombinant SP-D as a standard and horseradish peroxidase conjugated F(ab')2 fragment of mouse monoclonal antibody IgG to avoid the interaction of serum factors including rheumatoid factor. The use of F(ab')2 fragment dramatically decreased the value of serum SP-D concentration in rheumatoid arthritis patients without pulmonary complication to the close level of healthy volunteer. In contrast, the patients with collagen disease having interstitial pulmonary pneumonia exhibited consistently elevated levels of serum SP-D. The use of new ELISA with recombinant SP-D and F(ab')2 fragment of anti-SP-D monoclonal antibody gives a greater advantage for the accurate detection of SP-D in sera from patients with idiopathic pulmonary fibrosis, interstitial pneumonia with collagen disease and pulmonary alveolar proteinosis without interference of rheumatoid factor.

Adult↗
PubMed1997

Expression of a kinase-defective Eph-like receptor in the normal human brain.

We have identified a human Eph-family protein, HEP, gene located in human chromosomal region 7q33-->q35. The deduced amino acid sequence shared primary structural properties of Eph-family receptor tyrosine kinases. However, six invariant amino acids such as a lysine in the ATP-binding site and an aspartic acid in the phosphotransfer site of a conserved catalytic domain were substituted with other amino acid residues in HEP. Thus, no intrinsic tyrosine kinase activity was detectable in the catalytic domain expressed in CHO-K1 cell transfectants. Although most kinase-defective mutants of growth factor receptors have been reported as pathogenic receptors, its transcript was abundantly expressed in normal human adult tissues. A 135-kDa HEP protein was expressed in the human brain as much as in CHO-K1 cells transfected with a HEP cDNA expression vector. HEP is the first description of a kinase-defective Eph-family protein expressed abundantly in normal human tissues.

Adenosine Triphosphate↗
PubMed1997

High-performance liquid chromatographic separation of microcystins derivatized with a highly fluorescent dienophile.

Microcystins are potent hepatotoxins produced by cyanobacteria, and are also tumor promoters as well as potent inhibitors of the catalytic subunits of protein phosphatases 1 and 2A. In order to establish a physicochemical method for individual detection and determination of trace amounts of microcystins, we developed a derivatization method for fluorescence (FL) and chemiluminescence (CL) detection, in which a highly fluorescent dienophile, DMEQ-TAD (4-[2-(6,7-dimethoxy-4-methyl-3-oxo-3,4-dihydroquinoxalinyl) ethyl]-1,2,4-triazoline-3,5-dione), was used as the labeling reagent. DMEQ-TAD reacted smoothly with the conjugated diene of the Adda moiety to give 2 stereoisomers of the adducts. As a result of the extensive experiments, the following reaction conditions were optimized for the labeling: sample amount, 10 micrograms; reaction solvent, DMF:acetonitrile (1:1); reaction time, 15 minutes; reaction temperature, 70 degrees C; amount of DMEQ-TAD used relative to that of microcystin, 80 equivalent. The resulting 6 adducts from microcystins-LR, -YR, and -RR can be separated from one another using the following reversed phase HPLC conditions in combination with a clean-up using ODS silica gel: column, Cosmosil 5C18-AR (150 x 4.6 I.D. mm); mobile phase, methanol:0.05M phosphate buffer (pH 3) (1:1); flow rate, 1.0 ml/min; detection, FL lambda ex 370 nm, lambda em 440 nm. The detection limits of the DMEQ-TAD derivatives were estimated to be 100 and 500 pg for LR, and 65 and 2,500 pg for RR using FL and CL detections, respectively; and the detection behavior was different from that of the Dns-Cys derivatives, which were more sensitive to CL than FL.

Bacterial Toxins↗
PubMed1997

Thyroid-stimulating antibody and TSH-binding inhibitor immunoglobulin in 277 Graves' patients and in 686 normal subjects.

TSH receptor antibodies (TRAb) are believed to cause hyperthyroidism of Graves' disease. Thyroid-stimulating antibody (TSAb) and TSH-binding inhibitor immunoglobulin (TBII) have been measured as TRAb to diagnose Graves' disease and to follow Graves' patients. We intended to evaluate the clinical value of TRAb (TSAb and TBII) assay in establishing the diagnosis of Graves' disease and in predicting its clinical course. TSAb and TBII were studied in 686 normal subjects and in 277 Graves' patients before antithyroid drug therapy. We followed serial changes of TSAb and TBII in 30 Graves' patients before, during and after antithyroid drug therapy over 3.5-9 yr. We measured TSAb as a stimulator assay and TBII as a receptor assay. Both TSAb and TBII were distributed normally in 686 normal subjects. ROC curves demonstrated that both TSAb and TBII had high sensitivity and specificity for the diagnosis of Graves' disease, and were equally sensitive and specific; 150% was chosen as cut-off value for TSAb and 10% for TBII. Of the 277 untreated Graves' patients, 254 (92%) had positive TSAb and positive TBII. All of the 277 untreated Graves' patients had positive TRAb (TSAb and/or TBII). We followed the serial changes of TSAb and TBII in 30 Graves' patients over 3.5-9 yr. During antithyroid drug therapy, TSAb and TBII activities decreased and disappeared in 27 patients (Group A), but continued to be high in the other 3 (Group B). The former 27 Group A patients achieved remission, but the latter 3 Group B patients continued to have hyperthyroidism. Of the 27 Group A patients, 16 (59%) had parallel decreases of TSAb and TBII activities; in 6, the changes were predominantly observed in either TSAb or TBII, and in 4, complex changes in TSAb and TBII activities were observed. Disappearance of TSAb and appearance of TSBAb was seen in one. The other 3 Group B patients continued to have high TSAb and TBII activities and to have hyperthyroidism. In conclusion, TSAb and TBII are of clinical value in establishing the diagnosis of Graves' disease and in predicting its clinical course. We clearly demonstrated its diagnostic usefulness. Both TSAb and TBII have high sensitivity and specificity. All of the 277 untreated Graves' patients had TRAb (TSAb and/or TBII). Serial changes of TSAb and TBII during therapy differ from one patient to another, and can be classified into several groups. Changes in TSAb and TBII activities reflect the clinical courses of Graves' patients. The simultaneous measurement of both TSAb and TBII is clinically useful, since TSAb and TBII reflect two different aspects of TRAb. TSAb and TBII are different.

Adolescent↗
PubMed1997

DNA-alginate complex recognized by autoantibodies against DNA.

Double-stranded DNA was effectively complexed with alginic acid and immobilized on a surface of polystyrene microtiter plate. Dose-dependent binding of anti-DNA autoantibodies was finely observed to the solid phase DNA-alginate complex in enzyme-linked immunosorbent assay (ELISA). In contrast, non-specific binding of antibodies to alginate was scarcely detected rather than to poly-L-lysine. These results shown an availability of the solid phase DNA-alginate complex as an antigen in ELISA for detection of anti-DNA antibodies.

Alginates↗
PubMed1997

Demonstration of fragments with thyroid stimulating activity from thyroid stimulation blocking antibodies-IgG molecules by papain digestion.

OBJECTIVES: Thyroid stimulation blocking antibodies (TSBAb) inhibit TSH action and may have a role in the pathogenesis of hypothyroidism. In order to study the relationship between blocking and stimulating activities we have examined the biologically active fragments in TSBAb-IgG molecules after papain digestion. DESIGN: Both thyroid stimulating (TS) activity (cAMP production in thyroid cells) and TSH binding inhibitory (TBI) activity (determined by TSH receptor assay) in sera from patients with primary hypothyroidism were examined after digestion with papain-Sepharose in the presence of cysteine. The digested IgG was separated into unbound (UF) and bound (BF) fractions on a Protein A-Sepharose column. Each fraction was then gel-filtrated on a Sephadex G-100 column. RESULTS: TS activity was found within one hour after hydrolysis in 5 out of 7 antibodies, then gradually decreased after more prolonged incubation. Both TS and TBI activities in the UF and the BF from Protein A were found in Feb (Mr 50 kD) and the second protein peak (Fc with trace amounts of Fab), respectively. The biological activity in the second protein peak was suggested as being derived from Fab fraction, because the activity bound to the anti-F(ab')2 column. However, the first peak (undigested IgG) in the BF had neither TS nor TSB activity. The TS activity in the retarded fraction (less than Mr 20 kD) in the UF gradually increased with prolonged digestion. CONCLUSIONS: The conversion of Thyroid stimulation blocking antibodies activity to thyroid stimulating activity by papain digestion suggests that the inherent thyroid stimulating activity located in the Fab portion of the IgG molecule is unmasked by papain cleavage. We also suggest that the thyroid stimulating activity in the retarded fraction in the unbound fraction may be released from hydrolysis of the Fab portion of the IgG molecule.

Antibodies, Blocking↗
PubMed1997

Calmodulin purified from human and porcine thyroids inhibits thyrotropin binding to porcine thyroid cells.

A thyrotropin (TSH) binding inhibiting protein (TBIP) that inhibits TSH binding to the TSH receptor, as determined by the TSH receptor assay, was purified from human and porcine thyroid. The soluble fraction (100,000 x g supernatant of Graves' thyroid homogenate) was precipitated with ammonium sulfate between 1.75 to 2.5 mol/L. TBIP was eluted by 0.5 mol/L sodium chloride (NaCl) containing 20 mmol/L Tris buffer, pH 7.5 from a Q-sepharose column. The unbound fraction from concanavalin A (Con A) and blue-sepharose was gel-filtered using sephadex G-100, and finally purified by Resource Q column chromatography. Purified TBIP was confirmed as a single protein band of 17 kDa. The TBI activity in the purified TBIP was significantly decreased by either etnylene glycol tetraacetate (EGTA) (1 mmol/L) or antibody to calmodulin (CaM) in the TSH receptor assay. The TBIP was confirmed immunologically as CaM by the Ouchterlony method using antibody for CaM. These findings demonstrated that the TBIP purified from human and porcine thyroids was, in fact, CaM. We examined the effects of TBIP purified from human thyroid on bovine TSH (bTSH) or thyroid stimulating antibody (TSAb)-stimulated cyclic adenosine monophosphate (cAMP) production in porcine thyroid cells (PTC). TBIP itself did not increase basal levels of cAMP production, but inhibited bTSH (100 mU/L)-stimulated cAMP production. However, TBIP did not inhibit cAMP production stimulated by TSAb-IgG and various thyroid stimulators (GTPgammaS, forskolin and pituitary adenylate cyclase-activating polypeptide [PACAP, 27 and 38 amino acids]). Authentic CaM purified from bovine brain behaved in a manner similar to that of TBIP. These data showed that CaM differentially affects thyroid stimulation by TSH and TSAb in intact thyroid cell experiments.

Animals↗
PubMed1997

A zinc finger protein required for stationary phase viability in fission yeast.

Yeast cells exit the cell cycle and enter a metabolically inert stationary phase when starved for nutrients essential for normal proliferation. We have cloned a novel gene named rsv1+ (required for stationary phase viability) that is essential for fission yeast cell viability in a stationary phase induced by glucose starvation. rsv1+ encodes a 47 kDa protein with two zinc finger motifs that are partially homologous with Aspergillus nidulans CreA, Saccharomyces cerevisiae Mig1 and mammalian EGR-1/NGFI-A. Cells deleted for rsv1+ are unable to survive glucose starvation. Transcription of rsv1+ is negatively regulated by the cAMP pathway and induced by glucose starvation. Cells with the constitutively activated cAMP pathway are known to lose viability when grown to confluence or when starved for glucose. These cells are poor in rsv1+ induction and their viability loss is largely suppressed by ectopic expression of rsv1+. Thus, poor induction of rsv1+ is at least partially responsible for the viability loss. Analysis also showed that cells need to receive starvation signals before entry into the stationary phase in order to maintain viability in a glucose-poor environment.

Amino Acid Sequence↗
PubMed1997

Glutamic acid decarboxylase65 (GAD65) antibodies and insulin auto-antibodies in Japanese patients with non-insulin-dependent diabetes mellitus.

To clarify whether glutamic acid decarboxylase65 antibodies (GAD65 Ab) and insulin autoantibodies (IAA) are good predictive markers for insulin-dependency in NIDDM, we studied GAD65 Ab and IAA in NIDDM patients treated with diet alone or in combination with oral hypoglycemic agents. GAD65 Ab were found in 12 or 29 (5.2%, P = 0.079 vs. control) NIDDM patients and IAA in 8 of 229 (3.5%). The frequency of GAD65 Ab and IAA positivity in NIDDM did not differ significantly from those of healthy controls (2/150, 1.3%, 2/150, 1.3%, respectively), but the frequency of patients who were positive for either GAD65 Ab or IAA, or both, was significantly higher than that of normal controls (17/229, 7.4% and 4/150, 2.7%, respectively, P < 0.05). In addition, the prevalences of GAD65 Ab and of IAA in those patients whose disease durations, since the diagnosis of diabetes, were less than one year were significantly higher than those of controls (4/30, 13.3%, P < 0.05, 4/30, 13.3%, P < 0.05, respectively). We found no differences between GAD65 Ab positive- and negative-patients in either BMI or serum C-peptide levels. Over a one to five year follow-up period (mean 2.0 yrs), serum C-peptide levels gradually decreased necessitating insulin treatment in three of the patients positive for GAD65 Ab and/or IAA (3/17, 17.6%; two were positive for both GAD65 Ab and IAA and one was positive for GAD65 Ab only). In contrast, only five patients negative for the two antibodies developed insulin requirement (5/212, 2.4%, P < 0.01). These results suggest that GAD65 Ab and IAA are good markers for predicting the development of insulin dependency in NIDDM patients and that the predictive value for insulin-dependency in NIDDM is enhanced by measuring both antibodies.

Adolescent↗
PubMed1997

[Effects of intermittent wakening on sleep pattern of nighttime caregiver: an EEG study with a single subject].

In order to investigate the effects of night wakening on sleep pattern of caregiver, a woman aged 45 years was studied using electroencephalogram (EEG). After two adaptation nights, her all-night EEG readings were recorded for six nights. During the first three consecutive nights, the subject slept by the side of a patient at a private ward of hospital and wakened by herself several times a night to provide care for the patient (care nights). Of the later three nights, her sleep EEGs were recorded at her home (free nights). The first free night was following three care nights and the other two free nights were after 2 weeks. The results were summarized as follows; 1) Sleep period time (SPT) of care nights differed in different nights. In contrast to the SPT range of 356-367 min during free nights, it was 271-391 min during the care nights. 2) The rhythm of sleep cycles of care nights was not stable, though the subject wakened by herself, not using an alarm clock. 3) Although there were few changes occurring in sleep efficiency (SE) and percent each stage for SPT (%SPT) between the first and second care night, SE of the third care night was more similar to SE of free nights than SE of the first two care nights, and so was %SPT of the third care night. 4) Sleep latency (SL) decreased during the four consecutive nights, i.e. the three care nights and the first free night, and SL of the third care night and the first free night were shorter than SL of the last two free nights. The accumulation of fatigue and stress of nighttime care was suggested.

Caregivers↗
PubMed1997

[A case of tabes dorsalis observed in an HTLV-1 carrier].

We report a case of a 53-year-old female HTLV-1 carrier with tabes dorsalis. In addition to typical symptoms of tabes dorsalis, she presented HTLV-1 associated myelopathy (HAM) like clinical features such as sensory disturbance with thoracic sensory levels and bladder disturbance (pollakiuria). Although penicillin treatment did not improve in her neurological symptoms, steroid therapy was effective especially in HAM like symptoms. The CSF neopterin level was markedly decreased after steroid therapy, indicating that inflammation in the spinal cord was settled down after treatment. Our case suggests that CNS infection like tabes dorsalis may be modified by HTLV-1 infection and then present some atypical clinical features based upon altered immunological aspects of HTLV-1 carriers.

Carrier State↗
PubMed1996

G protein-coupled cholecystokinin-B/gastrin receptors are responsible for physiological cell growth of the stomach mucosa in vivo.

Many peptide hormone and neurotransmitter receptors belonging to the seven membrane-spanning G protein-coupled receptor family have been shown to transmit ligand-dependent mitogenic signals in vitro. However, the physiological roles of the mitogenic activity through G protein-coupled receptors in vivo remain to be elucidated. Here we have generated G protein-coupled cholecystokinin (CCK)-B/gastrin receptor deficient-mice by gene targeting. The homozygous mice showed a remarkable atrophy of the gastric mucosa macroscopically, even in the presence of severe hypergastrinemia. The atrophy was due to a decrease in parietal cells and chromogranin A-positive enterochromaffin-like cells expressing the H+,K(+)-ATPase and histidine decarboxylase genes, respectively. Oral administration of a proton pump inhibitor, omeprazole, which induced hypertrophy of the gastric mucosa with hypergastrinemia in wild-type littermates, did not eliminate the gastric atrophy of the homozygotes. These results clearly demonstrated that the G protein-coupled CCK-B/gastrin receptor is essential for the physiological as well as pathological proliferation of gastric mucosal cells in vivo.

Animals↗
PubMed1996

Autocrine loop through cholecystokinin-B/gastrin receptors involved in growth of human leukemia cells.

The cholecystokinin (CCK)-B/gastrin receptor binds two brain-gut hormones, CCK and gastrin, with high affinities. These peptides have a trophic effect on gastrointestinal cells expressing the receptor in vivo as well as in vitro. Recently, this receptor mRNA was reported to be expressed in immunocytes localized in the lamina propria of normal rat stomach mucosa. Here, we studied the receptor expression in human hematopoietic cells in order to determine whether they play a role in cell growth. The CCK-B/gastrin receptor mRNA was detectable in the polymorphonuclear (PMN) cells but not in the mononuclear cells of normal peripheral white blood cells by reverse transcription-polymerase chain reaction. The receptor transcript was, however, expressed in human leukemia cell lines (14 of 18 cell lines tested) derived from not only myeloid, but also T- and B- lymphoid lineages. The CCK-B/gastrin receptors on several leukemia cell lines were shown to be biologically active by demonstrating ligand-dependent cell proliferation in serum-deprived medium. Interestingly, a human CCK-B/gastrin receptor specific antagonist, YM022, but not its stereotype isoform, selectively inhibited the DNA synthesis of THP-1, MOLT-16, MOLT-14, and CCRF-CEM in the absence of exogenous peptide ligands. Further investigation revealed that these leukemia cell lines and normal PMN cells also expressed gastrin mRNA. These results suggest that growth of human leukemia cells is promoted by an autocrine mechanism through the CCK-B/gastrin receptors.

Cell Division↗
PubMed1996

A combined staining method for argyrophilic nucleolar organizer regions and for glial fibrillary acidic protein in astrocytes of human brain.

Different protocols are described for the combined staining method by which argyrophilic nucleolar organizer region sites can be evaluated in human astrocytes that are immunoreactive for glial fibrillary acidic protein. Among the four protocols studied, the following method was superior to others in terms of unambiguous visualization of the regions in glial fibrillary acidic protein-positive astrocytes; the first step was immunostaining for the protein with a blue colour reaction of alkaline phosphatase, followed by sequential colloidal silver staining for the regions. By this double staining method, we have demonstrated that the reactive astrocytes found in white matter around the metastatic lesion of carcinoma and the infarction, contain more argyrophilic nucleolar organizer regions in terms of the count as well as the area than glial fibrillary acidic protein-positive astrocytes present in the white matter of the normal brain. In conclusion, the double staining may provide valuable information on the cellular activity of astroglia when performed on routine formalin-fixed paraffin sections of the human brain.

Astrocytes↗