Biomedical subjects

M Maeda

Publications and source records attributed to M Maeda.

At least 901 records · Page 50Linked to original sources

PubMed1991

[Effects of lumbar epidural anesthesia on brainstem auditory response].

Auditory brainstem responses (ABR) are used increasingly to monitor the integrity of neural pathways in anesthetized patients. To evaluate the effect of epidural anesthesia on the central nervous system, we studied the effects of lumbar epidural anesthesia with lidocaine on the ABR in 10 patients. The seven peak latencies (waves I-VII) and amplitudes (waves I-VII) of the ABR were recorded before and 15 min after epidural anesthesia. Peak latencies of waves III, IV, V, VI, VII increased after epidural anesthesia compared with control values. Amplitude of waves II only decreased significantly following epidural anesthesia compared with control values. We further compared the interpeak latencies to investigate the brainstem transmission. Interpeak latencies (I-II, II-III, III-IV, IV-V, V-VI, VI-VII) were unchanged from the control values except waves VI-VII interval. Interpeak latencies of every second peak (II-IV, IV-VI, V-VII), of every third peak (II-V, III-VI, IV-VII), of every forth peak (I-VI, II-VII), of every fifth peak (I-VII) increased after epidural anesthesia compared with control values. The data obtained in the study demonstrated that lumbar epidural anesthesia with lidocaine prolonged the interpeak latencies of ABR. Considering that the waves of ABR are related to anatomically distinct sites in the auditory pathway (I; Acoustic nerve, II; Cochlear nucleus, III; Superior olivary complex, IV; Lateral lemniscus, V; Inferior colliculus, VI: Medial geniculate body, VII; Auditory radiation), the delay in the latencies of ABR seems to be present in the time intervals which involve more than two or three synaptic transmissions.

Anesthesia, Epidural↗

PubMed1991

[Effects of rectal premedication and the mother's presence on induction of pediatric anesthesia].

The effects of the rectal premedication and the mother's presence on induction of anesthesia were studied with 67 children between the ages of 1 and 6 years. All children were induced with mask using nitrous oxide-oxygen-halothane. Children's emotional states during induction were categorized as excellent, good or fair. Rating of excellent or good was considered to indicate satisfactory induction. Forty-seven children were accompanied by their mother. Twenty-two of them were premedicated with rectal bromazepam (3 mg), while another twenty-five children were not premedicated. Satisfactory induction after premedication was performed on 78% of the 1-3 year olds and 100% of the 4-6 year olds, whereas without rectal premedication, satisfactory induction was achieved in 42% of the 1-3 year olds and 69% of the 4-6 year olds. Rectal premedication was important for satisfactory induction. Another twenty of all children were premedicated with rectal bromazepam (3 mg) and induced without mother presence. Satisfactory induction was performed on 38% of the 1-3 year olds and 100% of the 4-6 year olds. Mother's presence tended to lead to satisfactory induction. Furthermore, we sought feedback from the mothers about their presence during induction of anesthesia. Almost all of the mothers said they appreciated the opportunity to be present, with the exception of four mothers (8.5%) who reported feeling of some anxiety to be in an operating room.

Administration, Rectal↗

PubMed1991

[A case of the primary pancreatic lymphoma].

Primary pancreatic lymphoma is extremely rare. A case of the primary pancreatic lymphoma was described. A 74-year-old man was admitted to our hospital on May 26, 1990, because of epigastralgia and 5-kg weight loss. On admission, physical examination revealed mild epigastric tenderness without hepatosplenomegaly and superficial lymphadenopathy. The serum amylase level and trypsin level were normal but serum CA19-9 was slightly elevated. The diagnosis of the pancreatic cancer (body and tail) was strongly suspected on subsequent examination by US, CT, ERP and angiography. Partial pancreatectomy and splenectomy were performed. Pathological examination of the tumor in the pancreas showed diffuse non-Hodgkin's lymphoma and B-cell origin. Peripancreatic fat was involved but peripancreatic lymph nodes and spleen were intact, which strongly suggested that the isolated lymphoma was pancreatic origin.

Aged↗

PubMed1991

[Blood kinetics of free-platinum in CDDP hepato-arterial injection therapy].

In CDDP hepato-arterial injection therapy, platinum (Pt) concentration in hepatic and peripheral venous blood were determined in two groups with different injection rates, and the blood kinetics of Pt was examined. Seven cases of digestive cancers having liver metastases were given CDDP (100 mg) selectively into the proper hepatic artery at a constant rate (10 or 40 min). After injection, concentration of non-protein-bound Pt in hepatic and peripheral venous blood were determined. Pt concentration and AUC value were higher in hepatic venous blood at injection rate than peripheral venous blood. On the other hand, Pt concentration in hepatic venous blood in the cases 10 min-injection were higher than those received 40 min-injection, but neither Pt concentration in peripheral venous blood nor incidences of the side effects and abnormal clinical findings were influenced by the injected rates.

Adult↗

PubMed1991

[Effects of intravenous lidocaine administration on median nerve somatosensory evoked potentials].

The effect of lidocaine on the median nerve somatosensory evoked potential (SSEP) was investigated in 14 neurologically normal patients. Lidocaine 1.5 mg.kg-1.min-1 was injected intravenously over a 5 min period immediately followed by a continuous infusion of lidocaine 60 micrograms.kg-1.min-1. The peak latencies (N1, P2, N2) and amplitudes (N1-P2, P2-N2) of the SSEP response over the sensory cortex were recorded before and after lidocaine infusion. The peak latencies in the control group and in the experimental group after lidocaine infusion of N1, P1, N2 were 19.4 +/- 1.0 msec, 19.7 +/- 1.0 msec (N1), 24.6 +/- 1.4 msec, 25.0 +/- 1.5 msec (P2), 32.5 +/- 2.5 msec, and 33.3 +/- 2.8 msec (N2), respectively. The amplitudes in the control group and in the experimental group after lidocaine infusion of N1-P2, P2-N2 were 9.0 +/- 4.3 microV, 10.3 +/- 4.7 microV (N1-P2), 7.2 +/- 3.6 microV, 8.6 +/- 3.9 microV (P2-N2), respectively. Peak latencies of all components (N1, P2, N2) increased after lidocaine infusion compared with control values. Amplitude of N1-P2 and P2-N2 increased significantly following lidocaine infusion compared with control values. The data obtained in this study suggested that the changes in peak latencies and amplitude after epidural anesthesia with lidocaine were due to the systemic effect of lidocaine absorbed intravenously from the epidural space.

Aged↗

PubMed1990

The glycine-rich sequence of the beta subunit of Escherichia coli H(+)-ATPase is important for activity.

A short sequence motif rich in glycine residues, Gly-X-X-X-X-Gly-Lys-Thr/Ser, has been found in many nucleotide-binding proteins including the beta subunit of Escherichia coli H(+)-ATPase (Gly-Gly-Ala-Gly-Val-Gly-Lys-Thr, residues 149-156). The following mutations were introduced in this region of the cloned E. coli unc operon carried by a plasmid pBWU1: Ala-151----Pro or Val; insertion of a Gly residue between Lys-155 and Thr-156; and replacement of the region by the corresponding sequence of adenylate kinase (Gly-Gly-Pro-Gly-Ser-Gly-Lys-Gly-Thr) or p21 ras protein (ras) (Gly-Ala-Gly-Gly-Val-Gly-Lys-Ser). All F0F1 subunits were synthesized in the deletion strain of the unc operon-dependent on pBWU1 with mutations, and essentially the same amounts of H(+)-ATPase with these mutant beta subunits were found in membranes. The adenylate kinase and Gly insertion mutants showed no oxidative phosphorylation or ATPase activity, whereas the Pro-151 mutants had higher ATPase activity than the wild-type, and the Val-151 and ras mutants had significant activity. It is striking that the enzyme with the ras mutation (differing in three amino acids from the beta sequence) had about half the membrane ATPase activity of the wild-type. These results together with the simulated three-dimensional structures of the wild-type and mutant sequences suggest that in mutant beta subunits with no ATPase activity projection of Thr-156 residues was opposite to that in the wild-type, and that the size and direction of projection of residue 151 are important for the enzyme activity.

Amino Acid Sequence↗

PubMed1990

Effect of bis(bilato)-1,2-cyclohexanediammineplatinum(II) complexes on lung metastasis of B16-F10 melanoma cells in mice.

New platinum(II) complexes, bis(bilato)-1,2-cyclohexanediammineplatinum(II) which were lipophilic and water-miscible, were tested for antitumor activity against lung nodules from intravenously injected B16-F10 melanoma cells in C57BL/6 mice by intravenous administration of the complexes in water suspension form. Among them, DACHP(litho)2 and DACHP(urso)2 had high antitumor activity but others had no activity. The antitumor activity of DACHP(urso)2 was increased significantly by injecting it three times; T/C was over 280% with 100-day survivors of 3 of 6 mice tested. Large amounts of total platinum were found in lung and liver tissues by atomic absorption spectroscopy after single intravenous injection of DACHP(urso)2 suspension in ICR mice.

Animals↗

PubMed1990

Suppressive effects of intracellular glutathione on hydroxyl radical production induced by tumor necrosis factor.

Protective effects of intracellular glutathione (GSH) against the cytotoxicity of human recombinant tumor necrosis factor (TNF) were investigated. Three tumor cell lines (L-M, B-16, HeLa) were used as target cells. Exposure of these cells to buthionine sulfoximine (BSO) or diethyl maleate (DEM) resulted in the depletion of intracellular GSH content to 5.2-43.0% of control values and enhancement of their susceptibility to TNF cytotoxicity. The hydroxyl radical production in L-M cells stimulated by TNF was increased by treatment with BSO or DEM. These results are consistent with the suggestion that intracellular GSH exerts its protective function against the cytocidal effect of TNF by inhibiting the hydroxyl radical production stimulated by TNF.

Animals↗

PubMed1990

Effect of low-frequency electric stimulation on in vivo release of cholecystokinin-like immunoreactivity in medial thalamus of conscious rat.

Release of cholecystokinin-like immunoreactivity (CCK-LI) in the medial thalamus of conscious rats was measured by brain dialysis and enzyme immunoassay. Analgesia caused by low-frequency electric stimulation of the tibial muscle, the tsusanli acupuncture point, was judged by change of pain threshold due to the stimulation. Medical thalamic CCK-LI released was increased by peripheral electric stimulations of both the acupuncture point and the non-acupuncture point. Results suggest that CCK acts as a neurotransmitter in the medial thalamus, a part of the analgesia inhibitory system.

Acupuncture Analgesia↗

PubMed1990

An increase in regional brain blood flow during hypertension induced by chemical inhibition of the nucleus tractus solitarius in rats.

Passive or neurogenic hypertension was produced by ligation of the aorta or microinjection of glutamate diethyl ester (GDEE) into the intermediate one-third of the nucleus tractus solitarius (NTS), respectively, in 44 anesthetized, artificially ventilated rats. After bilateral sympathectomy, the blood flow (microsphere method) was increased in the cerebral cortex, thalamus, and mesencephalon in a pressure-dependent manner in the face of neurogenic hypertension, as compared with the flow during passive hypertension. We speculate that some neurogenic mechanism tends to impair cerebrovascular autoregulation when afferents arising from cardiovascular receptors were blocked by GDEE within the NTS.

Animals↗

PubMed1990

Expression of endogenous tumor necrosis factor as a protective protein against the cytotoxicity of exogenous tumor necrosis factor.

Based on the finding that expression of endogenous tumor necrosis factor (TNF) which is not detected in TNF-susceptible cells was observed in TNF-resistant cells, the assumption was made that endogenous TNF may be a protective protein against the cytotoxic activity of TNF. In order to confirm this possibility, we investigated the relationship between expression of endogenous TNF and TNF susceptibility by using the gene transfection method. When L-M, TNF-highly sensitive murine fibrosarcoma cells were transfected with a human TNF gene, the stable transfectants expressed endogenous TNF and acquired resistance to TNF. Conversely, when endogenous TNF synthesis was inhibited by introducing an antisense TNF gene into HeLa, TNF-less sensitive human cervical cancer cells, the sensitivity was enhanced. These findings indicate that endogenous TNF is one of the protective factors against the cytotoxic activity of TNF.

Animals↗

PubMed1990

Kinetic studies of chromaffin granule H+-ATPase and effects of bafilomycin A1.

Vacuolar type H+-ATPase purified from bovine chromaffin granules did not show simple Michaelis-Menten type kinetics, and had apparent Km values of 5 microM, 30 microM and 300 microM. These three Km values suggested the presence of catalytic cooperativity during steady-state hydrolysis. The single turnover rate was 10(-3)-fold the maximal velocity of the enzyme and similar to the rate estimated from the velocity of steady-state hydrolysis with the smallest Km value (5 microM). The H(+)-ATPase was inhibited by the stoichiometric binding of bafilomycin A1, a specific inhibitor of vacuolar type H(+)-ATPase. This inhibitor not only lowered the rate of ATP hydrolysis at the single catalytic site, but also affected the catalytic cooperativity of the enzyme.

Adenosine Triphosphatases↗

PubMed1990

Immunocytochemical localization of manganese superoxide dismutase (Mn-SOD) in the hippocampus of the rat.

The immunocytochemical distribution of manganese superoxide dismutase (Mn-SOD) was determined in the rat hippocampus. The enzyme was localized in the mitochondria. CA1 pyramidal cells were weakly immunostained, whereas CA3 pyramidal cells were strongly reactive. These differences in the intensity of the Mn-SOD immunostaining reactions may relate to variations in the sensitivity of subfields of the hippocampus to ischemia.

Animals↗

PubMed1990

Chemical stimulation of the nucleus tractus solitarii decreases cerebral blood flow in anesthetized rats.

In anesthetized (chloralose and urethane), paralyzed and artificially ventilated rats, the neurons in the nucleus tractus solitarius (NTS) were chemically stimulated by microinjections of L-glutamate and the cerebral blood flow (CBF) was determined using a combination of labeled microspheres (either 57Co, 113Sn and 46Sc or 141Ce, 85Sr and 46Sc). Unilateral chemical stimulation of the NTS (n = 14) decreased CBF significantly in most brain areas. The decrease in CBF was not due to the decrease in arterial blood pressure (ABP) because the CBF of the whole cerebral cortex during the chemical stimulation of the NTS was significantly smaller (P less than 0.05) than the CBF during controlled hemorrhagic hypotension (n = 10). In another group of rats (n = 6), moderate hypertension was induced by blood transfusion. Unilateral chemical stimulation of the NTS in these rats decreased ABP but it remained within normotensive range. A significant (P less than 0.05) decrease in CBF (from 62 +/- 28 (mean +/- S.D.) to 48 +/- 23 ml.min-1.(100 g)-1) and increase in cerebrovascular resistance (from 1.9 +/- 1.2 to 2.6 +/- 1.2 mm Hg per [ml.min-1.(100 g)-1]) was observed in the whole cerebral cortex of these rats. Chemical stimulation of the NTS did not affect the reactivity of the cerebral vessels to hypercapnea (n = 5). These results suggest that the cell bodies within the NTS may play a role in the control of cerebral circulation.

Animals↗

PubMed1990

Human gastric (H+ + K+)-ATPase gene. Similarity to (Na+ + K+)-ATPase genes in exon/intron organization but difference in control region.

The human gastric (H+ + K+)-ATPase gene (15 kilobases) was cloned, and its nucleotide sequence was determined. The gene has 22 exons and codes a protein of 1,035 residues including the initiator methionine (Mr = 114,047). A conserved lysine-rich sequence with inserted glycine residues was found near the amino terminus of the enzyme. The phosphorylation site and pyridoxal 5'-phosphate- and fluorescein isothiocyanate-binding residues found in the rat and pig enzymes are also conserved in the human enzyme. The positions of introns in the human (H+ + K+)-ATPase gene are essentially the same as those in the human (Na+ + K+)-ATPase alpha and alpha III subunits; but the first introns of the two enzymes are difficult to align, and unlike in the (Na+ + K+)-ATPase gene, the sixth exon in the (H+ + K+)-ATPase gene is not separated by an intron. Furthermore, the ninth intron is located two bases upstream of the position for the corresponding intron of the (Na+ + K+)-ATPase alpha III subunit. The similarity in organization of these two ATPase genes and the homology in the primary structures of their proteins (approximately 60%) suggest that these two genes were derived from a common ancestral gene. However, the 5'-flanking regions of the genes for (H+ + K+)-ATPase and the (Na+ + K+)-ATPase alpha (+) subunit show no apparent sequence homology, indicating that their transcriptions are regulated differently. The control region of the fast-twitch sarcoplasmic reticulum Ca2(+)-ATPase gene also showed no sequence homology to that of (H+ + K+)-ATPase. The 5'-flanking region of the (H+ + K+)-ATPase gene contains potential binding sites for RNA polymerase II and various transcriptional regulation factors and several direct and inverted repeat sequences which may be important for specific and controlled expression of the gene in gastric parietal cells. There are two polyadenylation signals in the 3'-flanking region of the (H+ + K+)-ATPase gene, but the sequence of this region shows no homology to those of the corresponding regions of the genes for the (Na+ + K+)-ATPase alpha and alpha III subunits.

Adenosine Triphosphatases↗

PubMed1990

[The movement of antineoplastic solutions in transcatheter hepatic arterial embolization].

Transcatheter hepatic arterial embolization (TAE) with gelatin sponge particles soaked in anticancer agents has been widely employed in the treatment of Hepatocellular carcinoma (HCC). The mechanism of TAE has been explained by blocking of blood flow to the tumor, however the role of anticancer agents used with embolic materials has remained unclear. The purpose of this study is to prove the role of anticancer agents used in TAE. 1) In eighteen cases of HCC and 4 cases of metastatic liver cancer, TAE was performed with gelatin sponge, anticancer agents and contrast media. The livers were examined by CT 4, 24 and 48 hours after TAE. A selective retention of contrast media containing anticancer agent in the tumor area was observed in 14 of 14 cases examined 4 hr. in 15 of 17 cases examined 24 hr and in 6 of 6 cases examined 48 hr after TAE. In the cases of metastatic liver cancer, retention of contrast media, was also observed in 4 of 4 cases examined at 24 hr and 3 of 3 cases examined 48 hr after TAE. 2) TAE was done in 12 cases of HCC by using gelatin sponge soaked in anticancer agent mixed with 99M-Tc-pertechnetate. Livers were observed by a scintillation camera 4 hr and 24 hr after TAE. A selective retention of 99M-Tc-pertechnetate in the tumor was observed in 12 of 12 cases examined 4 hr and in 3 of 3 cases examined 24 hr after TAE. 3) In one cases of HCC, hepatectomy was performed 2 days after TAE.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1990

H(+)-ATPase gamma subunit of Escherichia coli. Role of the conserved carboxyl-terminal region.

Cloned uncG genes (wild-type or in vitro mutagenized) for the Escherichia coli gamma subunit were introduced into the uncG mutant Gln-14----end), and the functions of the mutant subunits were studied. The F1's with Ala-283----end and Thr-277----end mutant gamma subunits had 63 and 14% of the wild-type ATPase activity, respectively, and mutants with these subunits showed reduced growth by oxidative phosphorylation, indicating that the 10 residues at the carboxyl terminus (286th residue) are important, but dispensable, for catalysis. On the other hand, F1 with a Gln-269----end gamma subunit was inactive. Replacement of conserved residues (Gln-269, Thr-273, or Glu-275) between Gln-269 and Leu-276 gave enzymes with significantly reduced ATPase activity (2-41% of that of the wild-type) and lower ATP-driven proton conduction. Thus these residues are required for the normal catalytic activity of F1, although they are not absolutely essential. Membranes with amino acid replacements (Thr-277----end, Gln-269----Leu, or Glu-275----Lys) and the frameshift mutation (downstream of Thr-277) had about 15% of the wild-type ATPase activity, but showed different degrees of ATP-dependent H+ translocation and growth yield by oxidative phosphorylation, suggesting that the gamma subunit, especially its carboxyl-terminal region, functions in coupling between catalysis and H+ translocation.

Amino Acid Sequence↗

PubMed1990

[Intraarterial urokinase infusion therapy for arterial occlusive disease of the pelvis and extremities with special reference to short-term high dose infusion].

Thirty-five complete arterial occlusions of pelvis and extremity in 29 patients were treated with intraarterial urokinase infusion therapy. In 28 limbs, the occlusions were due to arteriosclerotic change and in 7 lesions, the occlusions were due to Burger's disease. The patients with arteriosclerotic change ranged in age from 52 to 84 years with a mean age of 68 years, and the patients with Burger's disease ranged in age from 35 to 47 years with a mean age of 43 years. There were 24 men and 5 women. The estimated duration of the occlusion was from 5 days to 5 years with a mean duration of 11 months. The length of the occluded segments ranged from 1 to 45 cm with a mean length of 13.9 cm. The occlusion was located in the iliac artery in 13 patients, the femoral artery in 11 patients, both the iliac and the femoral artery in 2 patients, the popliteal artery in 5 patients, the femoro-popliteal artery in 1 patient, the brachial artery in 2 patients and the radial artery in 1 patient. The infusion catheter was gently advanced into the proximal portion of the clot over a flexible guide wire, and urokinase was infused at a rate of 5000-10000 IU/min, as a short term high dose infusion (SHI), until antegrade blood flow was reestablished. The catheter was then withdrawn to a point proximal to all of the remaining clot, and the infusion rate was reduced to 10000-20000 IU/h as a continuous low dose infusion (CLI). After thrombolytic recanalization, a percutaneous transluminal angioplasty (PTA) was performed in those cases which demonstrated a residual narrowing of the lumen. The initial success rate was 86%. Reocclusions were observed in 5 lesions (17%) and a second recanalization was successful in 2 of 3 patients. The 1-year cumulative patency rate following recanalization was 88.4% and the 2-year patency rate was 78.6%. No significant complications directly related to the procedure were observed. SHI combined with CLI and PTA appears to be an effective and safe therapy for chronic long segmental arterial occlusion.

Adult↗