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Biomedical subjects

Y Masuda

Publications and source records attributed to Y Masuda.

At least 451 records · Page 25Linked to original sources
PubMed1994

Development of the pharynx in normal and malformed fetuses.

We studied the development of the pharynx in human embryos and fetuses. Embryos and fetuses from 4.5 mm crown-rump length (CRL) to 40 mm CRL were processed for microscopic examination. Normal fetuses from 32 mm CRL to 250 mm CRL and fetuses with malformations of the central nervous system (CNS) were cut sagittally through the midline and their pharyngeal regions were examined macroscopically. Our observations suggested that, at an early embryonic stage, the notochord and basicranium might play important roles in the formation of the human pharynx. At a later stage, the growth of the maxillomandibular portion also appears to be important in the formation of the pharynx. The finding of malformation of the pharynx in fetuses with maldevelopment of the CNS suggests that the brain may play an important role in the formation of the pharynx.

Anencephaly↗
PubMed1994

Metabolism of 3,5,3',5'-tetrachlorobiphenyl by rat liver microsomes and purified P4501A1.

1. The metabolism of 3,5,3',5'-tetrachlorobiphenyl (TCB) was investigated with liver microsomes and purified P450 from the male Wistar rat. 2. One novel metabolite was produced after incubation with liver microsomes derived from the 3-methylcholanthrene (MC)- and 3,4,5,3',4'-pentachlorobiphenyl-pretreated rat, but not after incubation with those from the untreated or phenobarbital (PB)-pretreated rat. These results suggest that P450 isozyme(s) induced by MC-type inducers is involved in 3,5,3',5'-TCB metabolism. 3. The chemical structure of this metabolite was identified to be 4-hydroxy-3,5,3',5'-TCB by comparison of its retention time in glc and the ms with those of a synthetic sample. 4. Purified rat P4501A1, a major MC-inducible P450 isozyme, catalyzed the 4-hydroxylation of 3,5,3',5'-TCB, but P4502B1, a major PB-inducible isozyme, was inactive. 5. Reduced glutathione completely inhibited the formation of the hydroxylated metabolite, suggesting that 4-hydroxylation of 3,5,3',5'-TCB proceeded via the 3,4-epoxide.

Animals↗
PubMed1994

[Clinical characterization of allergic patients sensitized to Chamaecyparis obtusa--using AlaSTAT system].

Clinical characterization of patients with allergy to Chamaecyparis obtusa (Cypress) pollen and their specific IgE antibody was investigated by using AlaSTAT assay, a new method for measurement of antigen-specific IgE antibody. Positive rate of antigen-specific antibody in patients with allergic pollinosis was 83.5% for Japanese cedar pollen and 80.0% for Chamaecyparis obtusa pollen. 76.4% of patients were sensitized both to Japanese cedar and Chamaecyparis obtusa pollen, however, 7.9% were sensitized only to the latter. As for clinical symptoms, duration of attack was short and severity was mild or moderate in the patients sensitized only to Chamaecyparis obtusa pollen. Patients who visited hospital in April, in that Chamaecyparis obtusa pollen disseminated in the air predominantly, showed significant elevation in AlaSTAT scores compared with patients who visited in February and March (p < 0.05).

Adolescent↗
PubMed1994

Inhibitory properties of NIP-121, a potassium channel opener, on high potassium- and norepinephrine-induced contraction and calcium mobilization in rat aorta.

We examined the effects of NIP-121, a potassium channel opener, on KCl- and norepinephrine (NE)-induced contraction, the phasic-contraction under the Ca(2+)-free condition and cytosolic free-Ca2+ mobilization using isolated rat aorta. NIP-121 as well as cromakalim inhibited, in the KCl- and NE-contractions concentration dependently. Glibenclamide, an ATP-sensitive potassium channel blocker, competitively reversed their inhibition. On the other hand, they did not inhibit the phasic-contractions induced by NE in Ca(2+)-free medium. In Fura-2-loaded rat aorta, NIP-121 inhibited only the late phase of the NE-induced cytosolic Ca2+ level ([Ca2+]cyt) increases that were inhibited by nicardipine. However, it did not inhibit the first [Ca2+]cyt increase, which was completely abolished by repeated applications of NE in Ca(2+)-free medium. Neither did it inhibit phorbol ester-induced contraction. The vasorelaxant mechanism of NIP-121 is attributable to the decrease in Ca2+ influx passing through the membrane Ca2+ permeable systems. In addition, inhibition of Ca2+ release from sarcoplasmic reticulum (SR) and of protein kinase C (PKC) activation may not be involved in vasorelaxation induced by NIP-121.

Animals↗
PubMed1994

Double burst stimulation with submaximal current.

The present study evaluated responses to double burst stimulation (DBS) at supramaximal and submaximal currents in 30 adult patients. Usually, DBS is applied with supramaximal stimulation, but this may be quite uncomfortable for the awake patient. Therefore, the authors investigated whether it is possible to obtain an accurate assessment of significant residual neuromuscular blockade if the stimulus current is reduced to 30 mA. In all patients, neuromuscular response to DBS three three (DBS3.3), DBS three two (DBS3.2) and train-of-four (TOF) stimulation at supramaximal and/or submaximal currents was recorded using a mechanomyograph, and the ratios of the fourth to the first twitch (T4/T1) induced by TOF stimulation at supramaximal current, and the height of the second response to the first (D2/D1) induced by DBS at 30 mA and supramaximal current were calculated. The relations between control T4/T1 ratios determined by supramaximal TOF stimulation and D2/D1 ratios determined by supramaximal DBS3.3 and submaximal DBS3.3 were Y = 0.99X + 0.08 and Y = 1.01X + 0.04, respectively, and there was no statistical difference between the two regression lines. The same relation between T4/T1 ratios and D2/D1 ratios by DBS3.2 were Y = 0.69X + 0.05 and Y = 0.72X + 0.02, respectively, and there was no significant difference. It is concluded that evaluation of the response to DBS at 30 mA has the same reliability as evaluation with supramaximal current.

Adult↗
PubMed1994

[Clinical significance of P-glycoprotein expression and multidrug resistance assessed by in vitro thymidine incorporation assay in patients with gastric carcinoma].

Drug resistance in chemotherapy is a significant problem in the treatment of gastric carcinomas as well as other malignant tumors. Multidrug resistant cells frequently overexpress the 170 kDa P-glycoprotein (P-gp). Twenty-four fresh tumor specimens of gastric carcinoma were assessed by flow cytometric detection of P-gp using monoclonal antibody C219. Eight patients were P-gp positive. Differentiated gastric carcinomas contained significantly higher concentrations of P-gp positive. Incidence of P-gp positive case was high in advanced stage. Sixteen cases received in vitro chemosensitivity test assessed by thymidine incorporation assay (TIA). Seven of 9 multidrug resistant cases by TIA were P-gp positive, and all of 7 non-multidrug resistance were negative. Expression of P-gp and multidrug resistance were closely correlated (p < 0.01). Also, in 89 patients with operable gastric carcinoma, the relationship between multidrug resistance by TIA and their clinicopathologic features as well as their survival lengths were examined. Thirty-one of 89 specimens from gastric carcinoma patients were multidrug resistant by TIA. Patients with multidrug resistant group had a significantly poorer cumulative survival rate than non-multidrug resistant cases (p < 0.01). The multivariated analyses showed that multidrug resistance analyzed is useful indicator for prognosis (p < 0.1). We suggest that multidrug resistance cases or P-gp-positive cases of gastric carcinoma are highly malignant, and these determinations are clinically useful.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Human carcinoma cell lines produce biologically active leukemia inhibitory factor (LIF).

We investigated the production of leukemia inhibitory factor (LIF) by human carcinoma cell lines. LIF mRNA was detected by Northern blot analysis in all 24 carcinoma cell lines of the lung, breast, stomach, colon, liver, gallbladder, pancreas and melanocytes. Seventeen of them (70.8%) secreted LIF in the culture supernatant (range: 40.4-3990.3 pg/ml, mean +/- SEM: 611.8 +/- 262.9 pg/ml). Biologic activity of LIF was confirmed in the culture supernatant of carcinoma cell lines by the MTT assay using M1 cells. The present results showed that human carcinoma cell lines are constitutively producing biologically active LIF. The possible biological significance of LIF produced by cancer cells is discussed.

Blotting, Northern↗
PubMed1994

[Sevoflurane anesthesia for a patient with facioscapulohumeral muscle dystrophy].

We gave anesthesia to a patient with facioscapulohumeral muscle distrophy (FSHMD). Patient was an 18 year old male, having no peculiar complaint and without family history nor past history relating to FSHMD. The restriction of right arm lifting was pointed out in medical examination. Diagnosis of FSHMD was made by muscle biopsy. The thoraco-scapula fixation was scheduled. Four hours prior to the induction, dantrolene 50 mg was administered per os. Before the induction, to estimate the effect of neuromuscular blockade, we applied Datex Relaxograph to the upper and lower extremities. Anesthesia was induced with thiamylal 200 mg and vecuronium 4 mg, and maintained with sevoflurane and nitrous oxide monitoring ETCO2. The time for the onset of muscular relaxation after the administration of vecuronium was quite different between upper and lower extremities (200 sec. and 407 sec.). Neostigmine and atropine for the reversal of neuromuscular blockade was administered evaluating the extent of neuromuscular relaxation obtained from Datex Relaxograph. We concluded that Relaxograph is essential as a monitor of muscular relaxation, especially in the case of neuromuscular disease.

Adolescent↗
PubMed1994

Evidence against a significant implication of carbonic anhydrase inhibitory activity of zonisamide in its anticonvulsive effects.

To clarify whether the inhibitory effect of zonisamide (Excegran, CAS 68291-97-4) on carbonic anhydrase contributes to its anticonvulsant activity, the anticonvulsant activity of 7-methylated zonisamide, a zonisamide analogue which has the same potency of activity as zonisamide in inhibiting carbonic anhydrase in vitro, has been examined. The study using mice did not reveal 7-methylated zonisamide to have any anticonvulsant activity even though its brain concentration level was more than two times the minimal effective concentration of zonisamide. These findings indicate that the anticonvulsant effect of zonisamide is derived from a mechanism(s) other than inhibition of carbonic anhydrase.

Animals↗
PubMed1994

[A new neuromuscular transmission monitor (TOF Guard): the rationale behind the method and its clinical usefulness].

TOF Guard is one of the latest developments in the field of neuromuscular monitoring equipment. This system uses a miniature acceleration transducer (a piezo-electric ceramic wafer is used), simply fastened to the thumb with tape. The rationale behind the method is Newton's second law, stating that the acceleration is directly proportional to the force. In this study, authors assessed the accuracy of this system in clinical use, comparing with the force transducer method (Myograph 2000). The result showed that there was a very close positive correlation between the values of T1, TOF ratio and posttetanic count simultaneously measured by both methods. The coefficient of correlation was 0.96, and its significance level was P < 0.001. From the clinical view point, it is concluded that TOF Guard is very useful because of its accuracy and because the equipment is easy to handle, compact and of low price as a neuromuscular monitoring system for routine anesthesia.

Adult↗
PubMed1993

Purification and characterization of the receptor for pituitary adenylate cyclase-activating polypeptide.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a 38-amino acid peptide (PACAP38) or a truncated peptide with the same 27 amino-terminal residues (PACAP27). The PACAP receptor was solubilized from bovine brain membranes with digitonin and purified 30-fold by the combination of DEAE-Toyopearl and hydroxylapatite chromatographic analyses. The partially purified PACAP receptors were mixed with biotinylated PACAP27 to form receptor-ligand complexes and then adsorbed onto avidin-agarose. The adsorbed PACAP receptors were eluted with an acidic buffer containing 1.0 M NaCl (pH 4.0). The eluted receptors were purified further by hydroxylapatite and gel filtration chromatography. A single protein band with a M(r) = 55,000-60,000 was found in the final preparation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining. Affinity labeling of the purified receptors with 125I-PACAP27 labeled the M(r) 55,000-60,000 protein specifically. The dissociation constant and the specific activity of the purified receptors were 25.8 pM and 17.2 nmol of ligand binding per mg of protein, respectively. Inhibitory constants determined by competitive binding experiments were 30.0 pM for PACAP27, 4.6 pM for PACAP38, and 37.3 nM for vasoactive intestinal peptide. Therefore, the purified PACAP receptor retained high affinity and ligand specificity. The sequence of the amino-terminal 29 residues was derived from the purified receptor.

Amino Acid Sequence↗
PubMed1993

Carbon tetrachloride-induced cell death in perfused livers from phenobarbital-pretreated rats under hypoxic conditions and various ionic milieu. Further evidence for calcium-dependent irreversible changes.

The role of Ca2+ in the initiation of carbon tetrachloride (CCl4) hepatotoxicity was studied using perfused livers isolated from phenobarbital-pretreated rats in a single-pass system. Krebs-Henseleit bicarbonate buffer containing 1.3 mM CaCl2 (KHB) was the regular ionic milieu. In the liver perfused with fructose-supplemented regular KHB equilibrated with 95% N2-5% CO2, infusion of 0.5 mM CCl4 caused an early uptake of Ca2+ coupled with K+ leakage and Na+ uptake within the infusion time of 30 min, which was followed by a marked lactic dehydrogenase (LDH) leakage into the effluent perfusate and further Ca2+ uptake by the liver. With Ca(2+)-free medium, the prenecrotic K+ leakage and the successive LDH leakage were suppressed markedly. However, a perfusate exchange from regular to Ca(2+)-free KHB at the end of the prenecrotic stage did not protect against the LDH leakage, and the perfusate exchange conversely did not produce LDH leakage. Perfusion of the liver with high K+(Cl-) medium under 20% O2 markedly suppressed CCl4-induced LDH leakage even in the presence of Ca2+, whereas once CCl4 had acted under regular KHB perfusion, changing the medium to high K+ did not further prevent the LDH leakage. High K(+)-lactobionic acid medium containing Ca2+ and supplemented with fructose also suppressed LDH leakage under 95% N2 without the accompanying prenecrotic Ca2+ uptake. However, a change of the medium after CCl4 infusion to regular KHB containing Ca2+ caused LDH leakage and K+ leakage, with Ca2+ uptake. The prevention of LDH leakage in a different ionic milieu may not be due to suppression of CCl4 bioactivation, since the liver cytochrome P450 content decreased to a similar extent. These findings suggest that entry of extracellular Ca2+ into hepatocytes coupled with K+ leakage and Na+ entry is a prerequisite for CCl4-induced hepatocyte death and that association of Ca2+ with a CCl4-derived radical-mediated process may be necessary for early and irreversible plasma membrane damage.

Animals↗