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Biomedical subjects

A Maeda

Publications and source records attributed to A Maeda.

At least 289 records · Page 16Linked to original sources
PubMed1993

[Intensive care of a postpartum patient complicated with HELLP syndrome].

We reported our intensive care experience of a postpartum patient with HELLP syndrome. We administered haptoglobin immediately after the delivery in order to prevent renal insufficiency following hemoglobinuria. Continuous veno-venous hemofiltration was undertaken and plasma exchange was also employed to overcome hepatorenal insufficiency. After these procedures an improvement was observed in her hepatic and renal functions. Administration of haptoglobin and blood purification would be beneficial for patients complicated with HELLP syndrome.

Adult↗
PubMed1993

[Effects of intravenous infusion of isosorbide dinitrate on hemodynamics during anesthesia and surgery].

Ninety nine patients with ischemic changes of the heart on preoperative and intraoperative ECG tracings were studied to evaluate effects of intravenous infusion of isosorbide dinitrate on hemodynamics during anesthesia and surgery. These patients ranging in ages from 24 to 80 years were administered intravenous isosorbide dinitrate at a rate of either 0.5 or 1 microgram.kg-1 x min-1 during anesthesia and surgery. Arterial blood pressure was not influenced with intravenous isosorbide dinitrate at the speed of 0.5 microgram.kg-1 x min-1 during anesthesia and surgery. The arterial pressure of the patients decreased slightly but significantly 30 min after the start of 1 microgram.kg-1 x min-1 of isosorbide dinitrate infusion, but it recovered to the control level at the end of administration of isosorbide dinitrate. Heart rate was unchanged with intravenous isosorbide dinitrate during anesthesia and surgery in both groups, except a mild increase at the end of isosorbide dinitrate infusion of 1 microgram.kg-1 x min-1. Arterial blood oxygen tension showed no decrease during the administration of isosorbide dinitrate and no adverse reactions associated with administration of the drug was detected in this study. Significant improvement of ischemic changes on ECG tracings were observed in about 25% of the patients who received 1 micrograms.kg-1 x min-1 of intravenous isosorbide dinitrate.

Adult↗
PubMed1993

[A case report of total intravenous anesthesia for renal transplantation].

A 20-year-old female patient with chronic renal failure received renal transplantation under total intravenous anesthesia with droperidol, fentanyl and ketamine. Anesthesia was induced with droperidol 12.5 mg, fentanyl 100 micrograms, ketamine 100 mg and vecuronium bromide 5 mg, and maintained with fentanyl and ketamine. Ketamine was given continuously at a rate of 2.0 mg.kg-1.h-1. After the renal artery and vein of the donor kidney were anastomosed with the patient's internal iliac artery and vein, the urine output of 7.7 ml.min-1 was obtained. The patient recovered from anesthesia smoothly and her postoperative course was uneventful. Although plasma epinephrine, cortisol and ADH levels showed significant changes during anesthesia mainly due to surgical stress, they returned to normal values after the end of operation. We conclude that this method of anesthesia would be a choice for renal transplantation.

Adult↗
PubMed1992

Tryptophan perturbation in the L intermediate of bacteriorhodopsin: fourier transform infrared analysis with indole-15N shift.

In the photoreaction of bacteriorhodopsin, the L intermediate shows an intense band at 3486 cm-1 which is unaffected by 2H2O (Maeda, A., Sasaki, J., Shichida, Y., & Yoshizawa, T. (1992) Biochemistry 31, 462-467]. This band is shifted to 3477 cm-1 by [indole-15N]tryptophan substitution and therefore is assigned to the N-H stretching vibration of the indole of tryptophan. Free indole in carbon tetrachloride shows its N-H stretching vibration at 3491 cm-1 [Fuson, N., Josien, M.-L., Powell, R. L., & Utterback, E. (1952) J. Chem. Phys. 20, 145-152]. Thus, it is suggested that at least one tryptophan residue in the L intermediate is not hydrogen bonded.

Bacteriorhodopsins↗
PubMed1992

Protein changes associated with reprotonation of the Schiff base in the photocycle of Asp96-->Asn bacteriorhodopsin. The MN intermediate with unprotonated Schiff base but N-like protein structure.

The difference Fourier transform infrared spectrum for the N intermediate in the photoreaction of the light-adapted form of bacteriorhodopsin can be recorded at pH 10 at 274 K (Pfefferlé, J.-M., Maeda, A., Sasaki, J., and Yoshizawa, T. (1991) Biochemistry 30, 6548-6556). Under these conditions, Asp96-->Asn bacteriorhodopsin gives a photoproduct which shows changes in protein structure similar to those observed in N of wild-type bacteriorhodopsin. However, decreased intensity of the chromophore bands and the single absorbance maximum at about 400 nm indicate that the Schiff base is unprotonated, as in the M intermediate. This photoproduct was named MN. At pH 7, where the supply of proton is not as restricted as at pH 10, Asp96-->Asn bacteriorhodopsin yields N with a protonated Schiff base. The Asn96 residue, which cannot deprotonate as Asp96 in wild-type bacteriorhodopsin, is perturbed upon formation of both MN at pH 10 and N at pH 7. We suggest that the reprotonation of the Schiff base is preceded by a large change in the protein structure including perturbation of the residue at position 96.

Asparagine↗
PubMed1992

Structures of aspartic acid-96 in the L and N intermediates of bacteriorhodopsin: analysis by Fourier transform infrared spectroscopy.

The light-induced difference Fourier transform infrared spectrum between the L or N intermediate minus light-adapted bacteriorhodopsin (BR) was measured in order to examine the protonated states and the changes in the interactions of carboxylic acids of Asp-96 and Asp-115 in these intermediates. Vibrational bands due to the protonated and unprotonated carboxylic acid were identified by isotope shift and band depletion upon substitution of Asp-96 or -115 by asparagine. While the signal due to the deprotonation of Asp-96 was clearly observed in the N intermediate, this residue remained protonated in L. Asp-115 was partially deprotonated in L. The C = O stretching vibration of protonated Asp-96 of L showed almost no shift upon 2H2O substitution, in contrast to the corresponding band of Asp-96 or Asp-115 of BR, which shifted by 9-12 cm-1 under the same conditions. In the model system of acetic acid in organic solvents, such an absence of the shift of the C = O stretching vibration of the protonated carboxylic acid upon 2H2O substitution was seen only when the O-H of acetic acid is hydrogen-bonded. The non-hydrogen-bonded monomer showed the 2H2O-dependent shift. Thus, the O-H bond of Asp-96 enters into hydrogen bonding upon conversion of BR to L. Its increased hydrogen bonding in L is consistent with the observed downshift of the O-H stretching vibration of the carboxylic acid of Asp-96.

Acetates↗
PubMed1992

Water structural changes in the bacteriorhodopsin photocycle: analysis by Fourier transform infrared spectroscopy.

The Fourier transform infrared difference spectra between light-adapted bacteriorhodopsin (BR) and its photointermediates, L and M, were analyzed for the 3750-3450-cm-1 region. The O-H stretching vibrational bands were identified from spectra upon substitution with 2H2O. Among them, the 3642-cm-1 band of BR was assigned to water by substitution with H2(18)O. By a comparison with the published infrared spectra of the water in model systems [Mohr, S.C., Wilk, W.D., & Barrow, G.M. (1965) J. Am. Chem. Soc. 87, 3048-3052], it is shown that the O-H bonds of the water in BR interact very weakly. Upon formation of L, the interaction becomes stronger. The O-H bonds of the protein side chain undergo similar changes. On the other hand, M formation further weakens the interaction of the same water molecules in BR. The appearance of a sharp band at 3486 cm-1, which was assigned tentatively to the N-H stretching vibration of the peptide bond, is unique to L. The results suggest that the water molecules are involved in the perturbation of Asp-96 in the L intermediate and that they are exerted from the protonated Schiff base which changes position upon the light-induced reaction.

Bacteriorhodopsins↗
PubMed1992

Relationship between endothelin and thromboxane A2 in rat liver microcirculation.

In our previous study, we determined changes in hepatic blood flow using a Laser Doppler blood flow meter after i.v. injection of endothelin-1 (ET-1) or endothelin-3 (ET-3) at 2 nmol/kg in rats and found that ET-3 caused greater decreases in blood flow than ET-1. In the present study, we determined how the arachidonic acid cascade, mainly thromboxane A2 (TXA2), is related to ET-1 and ET-3 using indomethacin (INDO), which inhibits the biosynthesis of prostaglandin (PG), and OKY-046, a selective inhibitor of TXA2 synthesis. In the first series of experiments, ET-1 and ET-3 were administered after inhibiting the biosynthesis of PG by s.c. injection of 2 mg/kg of INDO. While INDO failed to inhibit the slight decrease in hepatic blood flow induced by ET-1, it significantly inhibited the marked decrease in hepatic blood flow elicited by ET-3. In the next series of experiments, ET-1 and ET-3 were administered after administration of 20 mg/kg of OKY-046. OKY-046 showed no effects in animals treated with ET-1, as in those pre-treated with INDO, while it significantly inhibited the decreases in hepatic blood flow induced by ET-3. These findings suggest that ET-1 decreases hepatic blood flow due to its direct effects although to a lesser extent than ET-3, while ET-3 does so due not only to its direct effects but also to TXA2-mediated effects. It is therefore likely that in addition to ET family peptides, PG-mediated mechanisms are involved in the regulation of hepatic microcirculation by ETs.

Animals↗
PubMed1992

ET-3 sensitive reduction of tissue blood flow in rat liver.

Changes in gastric mucosal and hepatic tissue blood flow were simultaneously determined using a laser-Doppler blood flow meter in rats given i.v. injection of endothelin-1 (ET-1) and endothelin-3 (ET-3), both at 2 nmol/kg. Gastric mucosal blood flow decreased significantly after administration of ET-1 compared to after administration of ET-3. Decreases in blood flow due to ET-1 were reversed by pre-treatment with 10 mg/kg of BQ-123 (sodium salt), an ETA receptor antagonist, to levels comparable to those induced by ET-3, but BQ-123 had no effects on decreases in blood flow due to ET-3. On the other hand, decreases in hepatic tissue blood flow by ET-3 were significant compared to those by ET-1. Decreases in hepatic tissue blood flow due to ET-1 were slightly inhibited by pre-treatment with 10 mg/kg of BQ-123, but it had no effect at all on decreases due to ET-3. These findings indicate that decreases in gastric mucosal blood flow are mainly caused by ET-1 via ETA receptors inhibited by BQ-123, while decreases in hepatic tissue blood flow are caused mainly by ET-3 via non-ETA receptors not inhibited by BQ-123. The fact that ET-3 decreases blood flow more significantly than ET-1 suggests the involvement of ET-3 selective receptors (ETc). The findings obtained in the present study indicate that complex mechanisms are involved in the regulation of tissue blood flow by ET, with different receptor subtypes and ET family peptides being involved according to the type of tissue.

Animals↗
PubMed1992

Inhibition of mouse hepatitis virus multiplication by an oligonucleotide complementary to the leader RNA.

An oligonucleotide complementary to a leader RNA of positive-stranded mouse hepatitis virus (MHV) was tested for the effect on the viral multiplication in mouse DBT cells. A 14-mer antisense oligonucleotide contained a sequence complementary to the conserved pentanucleotide sequence, UCUAA, of the leader RNA. A treatment of MHV-infected cells with the antisense oligonucleotide at concentrations from 5 to 25 microM had an inhibitory effect on the viral multiplication and reduced the synthesis of viral specific mRNA and proteins. No inhibitory effect was observed when the cells were treated with sense oligonucleotide and oligonucleotide which contained unrelated sequences at concentrations from 1 to 10 microM. These results showed that antisense oligonucleotide against the leader RNA reduced the multiplication of positive-stranded RNA virus, MHV.

Animals↗
PubMed1992

The producer and biological activities of SO-75R1, a new mutactimycin group antibiotic [corrected].

The producer of SO-75R1, a new anthracycline group antibiotic was identified as Nocardia brasiliensis. SO-75R1 was active against Gram-positive bacteria, but not active against Gram-negative bacteria or fungi. All tested Nocardia brasiliensis strains as well as the producer itself were resistant to SO-75R1, although four other pathogenic Nocardia, i.e. N. asteroides, N. nova, N. farcinica and N. otitidiscaviarum were sensitive [corrected].

Animals↗
PubMed1992

[A case of multiple cranial nerve palsy with severe dysphagia due to herpes zoster infection].

A case of multiple cranial nerve palsy by herpes zoster was reported. A 79-year-old man showed fever, sore throat, and dysphagia. No vesicle was noted at ear and pharynx. The patient developed, later, left peripheral facial nerve palsy. The cerebrospinal fluid revealed pleocytosis with increased protein. The viral antibody titer of herpes zoster was significantly elevated both in cerebrospinal fluid and in serum. The left facial palsy was slightly improved. But his dysphagia didn't improve during at least 10 months after the onset. Among the cranial nerves, trigeminal and facial nerves are the most commonly affected by herpes zoster. But there are a few cases of the 9th and 10th cranial nerve involvement in the literature. However, dysphagia has rarely been reported in these previous cases, only four cases developed severe dysphagia like the present patient. All of these cases including our case were over sixty years old, while cases with slight dysphagia were under sixty years old. No other differentiating factor is noted between these two groups with regard to sites of vesicles, findings of cerebrospinal fluid and mode of therapy.

Aged↗
PubMed1992

[Clinical studies of panipenem/betamipron in pediatrics].

We conducted clinical studies on panipenem/betamipron (PAPM/BP), a newly developed parenteral carbapenem antibiotic, for its clinical application in the field of pediatrics. 1. A clinical study was performed on 13 children with infections, including 6 with acute bronchopneumonia, 1 each with acute pharyngitis, acute bronchitis, sepsis, staphylococcal scalded skin syndrome, urinary tract infection, subcutaneous abscess and furuncle. PAPM/BP was administered by intravenous drip infusion. Doses varied from 12 to 27 mg/kg body weight were given t.i.d. or q.i.d. Lengths of treatment ranged from 4 to 25 days. Clinical efficacies were excellent in 3 and good in 9 cases, with an efficacy rate of 92%. 2. No adverse reactions were observed. In laboratory tests, elevations of GOT, GPT and urobilinogen were observed in 3 cases. It was concluded that PAPM/BP was a promising drug for the treatment of bacterial infections in children.

Adolescent↗
PubMed1992

[Improvement of ADL and quality of life ].

Improvement of quality of life (QOL) of the patients with rheumatoid arthritis (RA) is very important. Practically, health status measurement (HSM) is beneficial to the assessment of QOL in arthritides, because the socioeconomical factor, one of 3 main factors in QOL, has numerous matters besides the medicine. There are many scales to assess health status so far, Health Assessment Questionnaire (HAQ) and Arthritis Impact Measurement Scales (AIMS) have been widely utilized because of their reliability, validity and sensitivity. We compared the health status in 105 of RA inpatients and that in 86 of RA outpatients by AIMS. Outpatients had significantly better physical status than inpatients. Our data showed a great discrepancy from that of Anderson. The reason for this discrepancy is presumably the differences in life style and daily activity between two countries. We are now trying to modify AIMS to fit Japanese.

Activities of Daily Living↗
PubMed1992

[Clinical evaluation of prostaglandin E1 during anesthesia in non-elderly and elderly patients].

The effects of prostaglandin E1 (PGE1) on blood pressure during anesthesia and the postoperative changes in organ functions were examined and compared in 358 cases. Two hundred and eighty patients were under 64 years of age and 128 patients were over 65 years. It was possible to control blood pressure satisfactorily with PGE1 in both non-elderly and elderly groups. However in the elderly group, it was more difficult to control blood pressure with PGE1 under NLA as compared with enflurane anesthesia. In both groups, urinary flow increased during and after the administration of PGE1, and the livers and kidneys showed neither dysfunction nor deterioration after operation. We had very few incidences of side effects with this drug. PGE1 is also considered safe and useful for elderly people during and after surgery.

Adolescent↗
PubMed1991

Fourier transform infrared study of the N intermediate of bacteriorhodopsin.

Visible absorption spectroscopic experiments show that the N intermediate is the main photoproduct of a highly hydrated film of the light-adapted bacteriorhodopsin (70% water by weight) at pH 10 and 274 K. The difference Fourier transform infrared spectrum between the N intermediate and unphotolyzed light-adapted bacteriorhodopsin was recorded under these conditions. A small amount of the M intermediate present did not affect this spectrum significantly. The difference spectrum exhibited a positive band at 1755 cm-1 (probably due to Asp-85) and a negative band at 1742 cm-1 (due to Asp-96), neither of which was observed for the M intermediate. The spectrum of the N intermediate at pH 7 was nearly identical with that at pH 10. Spectra at pH 10 also were measured with isotope-substituted samples. A vibrational band at 1692 cm-1 due to the peptide bond disappeared, and a band at 1558 cm-1 emerged upon formation of the N intermediate. The spectrum also displayed bands containing the N-H and C15-H in-plane bending vibrational modes at 1394 and 1303 cm-1. These frequencies are similar to those of the L intermediate while the intensities of these bands are larger than those in the L intermediate, suggesting that the Schiff bases of both the L and N intermediates have a strong hydrogen-bonding interaction with the protein and that the C12-H to C15-H region of the chromophore is less twisted in the N intermediate than in the L intermediate.

Bacteriorhodopsins↗