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Biomedical subjects

K Fujimori

Publications and source records attributed to K Fujimori.

At least 127 records · Page 7Linked to original sources
PubMed1996

Quantitative evaluation of passive cutaneous anaphylaxis (PCA) using a hand-held spectrophotometer.

A hand-held spectrophotometer was used for the quantitative evaluation of PCA caused by anti-TNP-IgE and TNP-BSA. A good relationship existed between the dilution of sera and the value of delta E*ab (a numerical expression of color) obtained by a hand-held spectrophotometer. In addition, the value of delta E*ab and the amount of Evans blue measured by the conventional colorimetric method correlated well. Because the method using a hand-held spectrophotometer provides a simple and objective analysis, it appears that the method is suitable as a substitute for the conventional method, which is time-consuming and requires killing animals cruelly.

Animals↗
PubMed1996

Biological activity of brain-derived neurotrophic factor with mismatched disulfide linkages produced by Escherichia coli.

E. coli cells harboring an expression plasmid with a brain-derived neurotrophic factor (BDNF) gene obtained from rat BDNF cDNA were sonicated and centrifuged to obtain a precipitate containing BDNF. Ten different proteins of BDNF were purified from the precipitate and the three disulfide linkages of six proteins were identified. Those disulfide structures were different from that of authentic BDNF and the biological activities of BDNF with mismatched disulfide linkages (EC50 of 2 to 15 ng/ml) were much lower than that of authentic BDNF (EC50 of 30 pg/ml). The BDNF with mismatched disulfide linkages inhibited the biological activity of authentic BDNF.

Animals↗
PubMed1996

Ventilatory response to continuous incremental changes in respiratory resistance in patients with mild asthma.

BACKGROUND: Conflicting results from previous studies on the effect of bronchial challenge on ventilatory patterns in asthmatics may be due to airflow obstruction present before induction of bronchospasm onset, as well as the different degrees of bronchoconstriction induced. PURPOSE AND METHODS: We examined the ventilatory response to stepwise increments in respiratory resistance (Rrs) induced by continuous methacholine inhalation in eight patients with mild stable asthma without airway obstruction and eight normal subjects. Methacholine was inhaled continuously during tidal breathing until a nearly two-fold increase in Rrs was observed. Respiratory parameters, including tidal volume (VT), respiratory frequency (f), inspiratory ventilation (VI), mean inspiratory flow (VT/TI), and duty ratio (TI/TT), were measured simultaneously by respiratory inductive plethysmograph (RIP). Arterial oxygen saturation (SaO2) was examined by pulse oximetry. The end-tidal CO2 fraction (FETCO2) was measured with a rapid-response infrared analyzer at the mouthpiece. RESULTS: Rrs, SaO2, FETCO2, and respiratory parameters, measured after saline solution inhalation, were not different between the two groups. Inhaled methacholine first decreased and then increased VI in both groups. However, changes in VI occurred earlier and to a greater extent in asthmatics than in normal subjects. At 200% Rrs (percent control), %VI was greater in asthmatics than in normal subjects (p<0.005) because of significant differences in %VT and %VT/TI between the two groups. CONCLUSION: For a given degree of bronchoconstriction, the ventilatory response was more rapid and greater in patients with mild stable asthma without airway obstruction than in normal subjects. The different response to bronchial challenge between the two groups may be due to different increases in drive due to irritant receptor stimulation.

Adult↗
PubMed1996

[Autoantibodies in bronchial asthma].

We studied the difference in the prevalence of autoantibodies between the sera of atopic asthma and non-atopic asthma. The presence of antinuclear antibodies (ANA) was evaluated in the sera of 20 patients with atopic asthma, 15 with non-atopic asthma, 20 with lung cancer, and 103 control subjects (40 with other pulmonary diseases and 63 with other medical diseases), by using an indirect immunofluorescent assay with HEp-2 cells as a substrate. The incidence of positive ANA was in the sera of 4/20 patients with atopic asthma, 8/15 with non-atopic asthma, 6/20 with lung cancer and 12/103 with control subjects, respectively. The incidence of positive ANA was found to be significantly higher in non-atopic asthma than in atopic asthma regardless of age or sex. One hypothesis is as follows. In non-atopic asthma, viral airway infection, as well as chronic eosinophilic inflammation of the airways, may cause some trouble in the impaired lymphocyte surveillance and may be especially liable to develop autoantibodies under those circumstances.

Adult↗
PubMed1995

Nonselective cation channels coupled with tachykinin receptors in rat sensory neurons.

1. Effects of substance P (SP) and other tachykinins on membrane currents were investigated using whole cell voltage clamp in cultured sensory neurons isolated from rat dorsal root ganglia. 2. SP (100 nM) evoked an inward current in two-thirds of the cells at negative potentials. In most of the cells that generated the inward current in response to SP, capsaicin also activated an inward current. The SP-evoked inward current was not observed in cells loaded with 2 mM guanosine 5'-O-(2-thiodiphosphate) (GDP beta S). 3. Neurokinin A (NKA) or neurokinin B (NKB) also activated an inward current. At 100 nM of each agonist, the order was NKB > NKA > SP with respect to activated current amplitude. 4. The tachykinin-activated current was reversed around +10 mV with a standard extracellular solution containing 140 mM NaCl. The reversal potential became more negative when extracellular NaCl was reduced by substituting with sucrose. The inward current was also activated in cells bathed in an extracellular solution containing Cs+, tetraethylammonium (TEA) or N-methyl-D-glucamine (NMDG) as a major cation instead of Na+. The order of permeability, determined from the reversal potential of the current, was Cs+ not equal to Na+ > TEA > NMDG. The amplitude of the inward current activated by NKB was increased when extracellular Na+ was replaced with Cs+, TEA or NMDG. 5. Permeability of Ca2+ was tested using an extracellular solution containing Ca2+ as the only cation (111.8 mM Ca2+ outside). Under this condition, NKB evoked an inward current that reversed around +30 mV. 6. The results suggest that SP and other tachykinins activate nonselective cation channels, which are also permeable to Ca2+, through receptors which are more responsive to NKB than to SP or NKA. The channel activation may serve as a mechanism underlying tachykinin-mediated excitatory neurotransmission in sensory neurons.

Animals↗
PubMed1995

Production of biologically active mature brain-derived neurotrophic factor in Escherichia coli.

A gene coding for a brain-derived neurotrophic factor (BDNF) obtained from rat BDNF cDNA was used to construct an expression plasmid, pTRSBDNF. It contained a BDNF gene that was fused, in frame, to a region encoding the beta-lactamase signal peptide. The E. coli HB101 harboring pTRSBDNF produced 18 mg/liter of mature protein. The E. coli cells produced a larger amount of BDNF than that of human nerve growth factor (hNGF), which was produced using the same expression system. The E. coli cells harboring pTRSBDNF were sonicated and centrifuged to obtain a supernatant and precipitate. The BDNF purified from the supernatant containing 20% of the total BDNF had high biological activity (EC50 of 30 pg/ml) against neurons of chick dorsal root ganglia. On the other hand, the BDNF purified from the precipitate had low biological activity (EC50 of 2 ng/ml) and incorrect disulfide bonds.

Amino Acid Sequence↗
PubMed1995

Viability of partial liver graft from living donor in pigs.

For evaluation of the viability of partial liver graft from a living donor, we investigated energy production of mitochondria and radical scavenging enzyme activities in partial and whole liver transplantation in pigs. The values of adenosine triphosphate (ATP) and total adenine nucleotide (TAN) of the partial liver graft were higher than those of the whole liver graft, whereas the hypoxanthine of the partial liver graft was lower than that of the whole liver graft. There was no statistical difference in the radical scavenging enzyme activities between the two groups. The values of respiratory control ratio (RCR) in both groups were above 3.0 and there was no statistical difference. The survival rates of pigs received partial liver and whole liver graft with 2 to 3 hr cold preservation was 71% and 91%, respectively and there was no statistical difference between two groups. These results suggest that viabilities of the partial liver graft from the living donor are satisfactory enough, compared with those of whole liver graft from a cadaver.

Adenine Nucleotides↗
PubMed1995

[Clinical implications of mismatched uptakes of beta-methyl fatty acid analogue and thallium in infarcted myocardium: correlations with coronary stenosis and regional wall motion abnormality].

Myocardial perfusion and fatty acid metabolism were assessed by using myocardial single-photon emission computed tomography with thallium and beta-methyl-p-iodophenyl-pentadecanoic acid (BMIPP) during acute and/or late stages of myocardial infarction in 157 infarcted segments of 100 patients. The incidence of reduced thallium perfusion relative to BMIPP uptake ("T-type" mismatch) was significantly (p < 0.05) lower (9%) compared to that of reduced BMIPP uptake relative to thallium perfusion ("B-type" mismatch) (59%) or non-mismatched segment (32%). In an anteroseptal region, B-type dissociation had a significantly higher incidence compared to no or T-type mismatch; 68% vs. 27% vs. 5%, respectively, whereas the incidence of T-type uptake was relatively high in inferior and posterolateral regions; 13%, 11%, respectively. Severe coronary stenosis was observed in 76% of B-type segments and 72% of non-mismatched segments but in only 43% of T-type segments. The incidence of regional wall motion abnormality was significantly lower (46%) in the T-type mismatch segments when compared to the B-type (91%) or non-mismatched segments (96%). In conclusion, myocardial fatty acid metabolism was more markedly impaired compared to an involved coronary perfusion, resulting in the mismatch of perfusion and fatty acid metabolism. Coronary stenosis and regional wall motion abnormality are more closely related to "B-type" mismatch but not necessarily to "T-type" dissociation, probably because of attenuation artifacts in inferior and posterolateral regions in thallium scan.

Aged↗
PubMed1994

Structural and regulatory functions of the NH2- and COOH-terminal regions of skeletal muscle troponin I.

Calcium binding to regulatory sites located in the NH2-terminal domain of troponin C (TnC) induces a conformational change that blocks the inhibitory action of troponin I (TnI) and triggers muscle contraction. We used deletion mutants of TnI in conjunction with a series of TnC mutants to understand the structural and functional relationship between different TnI regions and TnC domains. Our results indicate that TnI is organized into structural and regulatory regions which interact in an antiparallel fashion with the corresponding structural and regulatory regions of TnC. Functional studies show that the COOH-terminal region of TnI, when linked to the inhibitory region (TnI103-182) can regulate actomyosin ATPase. A TnI lacking the first 57 amino acids (TnId57) has been shown to have similar properties (Sheng, Z., Pan, B.-S., Miller, T. E., and Potter, J. D. (1992) J. Biol. Chem. 267, 25407-25413). Regulation was not observed with the COOH-terminal region alone (TnI120-182), with the NH2-terminal region alone (TnI1-98), or with the NH2-terminal linked to the inhibitory region (TnI1-116). Binding studies show that the NH2-terminal region of TnI interacts with the COOH-terminal domain of TnC in the presence of Ca2+ or Mg2+ and that the inhibitory plus COOH-terminal region of TnI (TnI103-182) interacts with the NH2-terminal domain of TnC in a Ca(2+)-dependent manner. Based on these results we propose a model for the Ca(2+)-induced conformational change. In our model the NH2-terminal domain of TnI is anchored strongly to the COOH-terminal domain of TnC in the absence and presence of Ca2+ while the inhibitory and COOH-terminal regions of TnI switch between actin-tropomyosin in the absence of Ca2+ to binding sites in both NH2- and COOH-terminal domains of TnC in the presence of Ca2+.

Amino Acid Sequence↗
PubMed1994

Endocrinologic and biophysical responses to prolonged (24-hour) hypoxemia in fetal goats.

OBJECTIVE: The purpose of this study was to observe some fetal endocrinologic and biophysical responses to prolonged (24-hour) nonacidemic hypoxemia in fetal goats. STUDY DESIGN: Endocrinologic and biophysical changes during continuous infusion of nitrogen into the maternal trachea were examined in six chronically instrumented goat fetuses at 123 to 131 days' gestation. We measured arginine vasopressin, adrenocorticotropic hormone, cortisol, epinephrine, and norepinephrine as endocrinologic parameters and fetal heart rate, fetal blood pressure, and fetal breathing movements as biophysical parameters. RESULTS: Fetal arterial PO2 declined from 25.1 +/- 2.1 mm Hg at baseline to 16.8 +/- 0.9 mm Hg at 1 hour of hypoxemia and remained at this level (p < 0.05). Arginine vasopressin, adrenocorticotropic hormone, and epinephrine initially rose in response to hypoxic stress, gradually declined, and by 24 hours were not significantly different from control values. Cortisol and norepinephrine remained significantly elevated through the experiments. Fetal breathing movements as a percentage of total time were 34.9% +/- 1.2% at baseline, 12.9% +/- 3.7% at 1 hour, and 70% to 80% of control values from 4 hours. Fetal heart rate was significantly reduced for the first 10 minutes, then progressively became tachycardiac thereafter. Systolic fetal blood pressure was significantly elevated for only 30 minutes. CONCLUSION: Arginine vasopressin, adrenocorticotropic hormone, and epinephrine of the endocrinologic parameters and fetal heart rate, fetal blood pressure, and fetal breathing movements are normalized during prolonged nonacidemic hypoxemia in fetal goats.

Adrenocorticotropic Hormone↗
PubMed1994

Modulation by alkyl p-hydroxybenzoates of voltage- and ligand-gated channels in peripheral neuronal cells.

Effects of alkyl p-hydroxybenzoates (APHBs), which are used as preservatives, on ion channels were investigated in rat pheochromocytoma PC12 cells. Methyl p-hydroxybenzoate (MPHB; 300 microM) and butyl p-hydroxybenzoate (BPHB; 300 microM) inhibited Ba2+ current passing through Ca2+ channels, and facilitated the inactivation of the Ba2+ current. K+ current obtained with a depolarizing voltage-step was also suppressed by 300 microM MPHB or 300 microM BPHB. The extent of the suppression of the K+ current was not affected by extracellular Cd2+, suggesting that the suppression of the K+ current is not a secondary effect arising from the Ca2+ channel inhibition. An inward current activated by acetylcholine (ACh; 100 microM) was abolished by 300 microM BPHB, and it was partially blocked by 300 microM MPHB. In contrast to the ACh-activated current, an inward current activated by ATP (30 microM) was markedly potentiated by 300 microM BPHB. The results suggest that APHBs exert significant effects on the voltage- and ligand-gated channels. The significance of these channel modifications were discussed in relation to reported effects of APHBs, including induction of minor irritation.

Acetylcholine↗
PubMed1994

Variable fetal heart rate decelerations and electrocortical activities.

OBJECTIVE: The purpose of this study was to examine the influence of fetal behavioral states on baroreflex-mediated, variable fetal heart rate decelerations caused by umbilical cord occlusion. STUDY DESIGN: Five chronically instrumented fetal lambs were subjected to intermittent partial umbilical cord occlusion for 1 minute every 3 minutes, lasting 2 hours. Fetal behavioral states determined by electrocorticogram and heart rates by electrocardiogram were monitored continuously during these experiments. RESULTS: The fetuses exhibited an alteration between low- and high-voltage electrocorticogram states. Both the depth and width of the variable fetal heart rate decelerations were greater during high-voltage than during low-voltage electrocorticogram. CONCLUSION: Amplitude and duration of variable fetal heart rate decelerations are affected by fetal behavioral states.

Animals↗
PubMed1994

Cushing's disease associated with adrenal myelolipoma, adrenal calcification and thyroid cancer.

A 51-year-old woman with Cushing's disease associated with adrenal myelolipoma is reported. A further characteristic feature was the coexistence of bilateral adrenal calcification and thyroid cancer. Previously several cases of adrenal myelolipoma associated with endocrine dysfunction were reported. The combination of Cushing's disease and adrenal myelolipoma has only been described in two cases of recurrent Cushing's disease but never in an initial occurrence of Cushing's disease. Continued stimulation by excessive adrenocorticotropic hormone (ACTH) not only developed adrenal hyperplasia but also might be involved in the pathogenesis of adrenal myelolipoma.

Adrenal Gland Neoplasms↗
PubMed1994

[A case of bronchial asthma associated with reflux esophagitis, whose peak expiratory flow rate improved with omeprazole and cisapride].

A 60-year-old male had visited our hospital periodically, because of perennial moderate atopic asthma, since 53 years of age. His symptoms had stabilized following treatment with oral theophylline 400 mg, tranilast 300 mg and inhalation of beclomethasone dipropionate 400 micrograms and procaterol hydrochloride. His peak expiratory flow rate early in the morning was 465 L/min, %VC was 115% and FEV1.0% was 62.4% in May of 1993. On May 24, 1993, though he had no gastrointestinal symptoms, gastrointestinal fiberscopy revealed a hiatal hernia, reflux esophagitis and active gastroduodenal ulcer. The upper gastrointestinal x-ray films showed gastroesophageal reflux. Therefore, we diagnosed bronchial asthma associated with reflux esophagitis and gastroduodenal ulcer. He was started on omeprazole, as a proton pump inhibitor (PPI), and cisapride. After the treatment with PPI and cisapride, his peak expiratory flow rate early in the morning and in the evening, %VC and FEV1.0 increased. Three months later gastrointestinal fiberscopy revealed improvement in the reflux esophagitis and the gastroduodenal ulcer. We speculate that the improvement in the peak expiratory flow rate is related to that of the gastroesophageal reflux.

Asthma↗
PubMed1994

Endogenous acetylcholine concentrations in rat iris-ciliary body.

The technique of microwave irradiation, whereby enzymes are inactivated within milliseconds, was employed to accurately determine the in vivo acetylcholine (ACh) concentration in the iris-ciliary body (ICB). Rats were sacrificed by microwave irradiation at 9.5 kW at 2,450 MHz for 0.9 seconds. The eyes were enucleated, the ICBs isolated and 10 ICBs from 10 eyes were treated as one sample. ACh levels were determined using high performance liquid chromatography in an immobilized-enzyme reactor. Endogenous ACh levels in the rat ICB were 58.8 +/- 5.0 nmoles (8.58 +/- 0.73 micrograms) per gram tissue protein (mean +/- SE, 9 samples). A single instillation of 5 microliters of 0.05% atropine in one eye of an animal lowered the ACh level in the ICB of the eye (P < 0.02).

Acetylcholine↗
PubMed1994

Endogenous catecholamine concentrations in rat iris-ciliary body.

Endogenous catecholamine concentrations in the rat iris-ciliary body (ICB) were determined using the technique of microwave irradiation, whereby enzymes are inactivated within milliseconds, and high performance liquid chromatography. Rats were sacrificed by microwave irradiation at 9.5 kW at 2450 MHz for 0.9 seconds. The eyes were enucleated, the ICBs isolated, and 10 ICBs from 10 eyes were treated as one sample. Endogenous norepinephrine levels in the rat ICB were 19.5 +/- 2.3 nmol per gram tissue protein (mean +/- SE, 7 samples), while endogenous dopamine levels were 3.2 +/- 0.2 nmol. Epinephrine could not be detected. A single instillation of 5 microliters of 0.05% apraclonidine, an alpha-2 agonist, in one eye of an animal raised the NE level in the ICB of the treated eye by 8% compared to that in the untreated fellow eye (P < 0.05).

Adrenergic alpha-Agonists↗