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Biomedical subjects

M Maeda

Publications and source records attributed to M Maeda.

At least 595 records · Page 33Linked to original sources
PubMed1995

Multiple genes encoding 2,3-dihydroxybiphenyl 1,2-dioxygenase in the gram-positive polychlorinated biphenyl-degrading bacterium Rhodococcus erythropolis TA421, isolated from a termite ecosystem.

Rhodococcus erythropolis TA421 was isolated from a termite ecosystem and is able to degrade a wide range of polychlorinated biphenyl (PCB) congeners. Genetic and biochemical analyses of the PCB catabolic pathway of this organism revealed that there are four different bphC genes (bphC1, bphC2, bphC3, and bphC4) which encode 2,3-dihydroxybiphenyl dioxygenases. As determined by Southern hybridization, none of the bphC genes exhibits homology to any other bphC gene. bphC1, bphC2, and bphC4 encode enzymes that have narrow substrate specificities and cleave the first aromatic ring in the meta position. In contrast, bphC3 encodes a meta cleavage dioxygenase with broad substrate specificity. Asturias et al. have shown that the closely related organism Rhodococcus globerulus P6 contains three different bphC genes (bphC1, bphC2, and bpHC3) which encode meta cleavage dioxygenases. The data suggest that there is a diverse family of bphC genes which encode PCB meta cleavage dioxygenases in members of the genus Rhodococcus.

Animals↗
PubMed1995

Metabolic alterations in the neonate and infant brain during development: evaluation with proton MR spectroscopy.

PURPOSE: To evaluate the usefulness of hydrogen-1 magnetic resonance (MR) spectroscopy in the evaluation of the developing brain. MATERIALS AND METHODS: Localized MR spectra were obtained with an echo time of 272 msec from the brain of 78 neonates and infants aged 1 week to 100 months. All patients were retrospectively classified into three groups on the basis of neurologic development: abnormal (group 2, n = 21), normal despite minor neurologic signs (group 1, n = 23), and normal (group 0, n = 34). RESULTS: Seventeen patients in group 2 and eight patients in group 1 revealed abnormally low N-acetylaspartate (NAA)/choline or NAA/creatine ratios compared with those obtained in group 0. MR spectroscopy was slightly more useful in the differentiation of patients in groups 2 and 1 (chi 2 test, P < .005) than MR imaging (P < .01). CONCLUSION: H-1 MR spectroscopy provides prognostic information about the brain in healthy and neurologically damaged infants and augments the value of MR imaging.

Aspartic Acid↗
PubMed1995

Hemorheological and hemodynamic analysis of hypervolemic hemodilution therapy for cerebral vasospasm after aneurysmal subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Hypervolemic hemodilution therapy is effective for treating neurological deficits due to cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH). We monitored various hemorheological and hemodynamic parameters to assess the effects of hypervolemic hemodilution therapy in SAH patients with cerebral vasospasm. METHODS: Ninety-eight patients who underwent early craniotomy for aneurysm clipping surgery after SAH were studied. Fifty-one patients (52.0%) developed symptomatic vasospasm. The hematocrit level and red blood cell aggregability were measured daily from day 1 to day 14, whereas the circulating blood volume and cerebral blood flow were measured periodically. Cardiac output and pulmonary capillary wedge pressure were also measured using a Swan-Ganz catheter. RESULTS: The hematocrit level was decreased significantly to 29% to 32% by hypervolemic hemodilution therapy. Red blood cell aggregability increased until day 6 but was significantly reduced by therapy. Hypovolemia tended to develop after SAH. However, patients receiving hypervolemic hemodilution therapy became normovolemic to hypervolemic, with a significant increase of cardiac output and pulmonary capillary wedge pressure. At the onset of vasospasm, cerebral blood flow was significantly lower on the operated side than on the contralateral side, and it increased on both sides with therapy. CONCLUSIONS: Patients with SAH develop hypovolemia, hemodynamic depression, and increased red blood cell aggregability. Hypervolemic hemodilution therapy decreases hematocrit level and red cell aggregability while increasing cardiac output. Improvement of hemorheological and hemodynamic parameters by this therapy can reverse neurological deterioration due to cerebral vasospasm.

Adult↗
PubMed1995

Human luteal cells express leukocyte functional antigen (LFA)-3.

Leukocyte functional antigen-3 (LFA-3)/cluster of differentiation-58 (CD-58) antigen is known as a ligand for CD-2 antigen, which is a specific surface marker of T-lymphocytes. To investigate the involvement of T-lymphocytes on corpus luteum (CL) function, the expression of LFA-3 in human CL was examined by the indirect immunofluorescence method with frozen sections. LFA-3 was not detected on the granulosa cells of primordial, primary, or atretic follicles, but was weakly expressed on the granulosa cells of growing and preovulatory follicles. After ovulation, LFA-3 was clearly expressed on large luteal cells of the CL in any stage of the luteal phase, and the highest expression was observed in the midluteal phase. Antigen expression was also observed in the large luteal cells in CL of pregnancy. Human granulosa cells were isolated from the patients who had undergone in vitro fertilization treatment and were cultured in vitro with or without hCG (1 IU/mL), tumor necrosis factor-alpha (TNF alpha; 10 ng/mL), or interleukin-1 alpha (10 ng/mL). By the indirect immunofluorescence method, LFA-3 was detected on granulosa cells after culture for 1 day, although the fluorescence intensity was very weak. LFA-3 was clearly detected on granulosa cells after 7 days of culture, especially on those with TNF alpha. Flow cytometrical analysis with 7-day cultured cells showed that the percent positivity of LFA-3-positive granulosa cells cultured with TNF alpha was significantly higher than that of the controls (without treatment; 66.5 +/- 3.7% vs. 34.3 +/- 4.9%; P < 0.01; n = 7). The percent positivity of cells cultured with interleukin-1 alpha was slightly higher (51.5 +/- 4.5%; P < 0.1) than that of the controls, whereas treatment with hCG caused no significant difference (46.6 +/- 4.7%) from the controls. These findings indicate that LFA-3 is a differentiation antigen of human granulosa cells. They also suggest that large luteal cells can interact, through LFA-3 molecules, with the CD-2 antigen-positive T-lymphocytes invading the CL after ovulation, and that the expression of LFA-3 is under the control of some cytokines, including TNF alpha.

Adolescent↗
PubMed1995

Integrin alpha 6 is a differentiation antigen of human granulosa cells.

We previously reported a new murine monoclonal antibody (mAb), OG-1, raised against human granulosa cells (GC) and showed that the OG-1 antigen is a cell surface differentiation-related molecule expressed on GC of follicles and on large luteal cells in the early to midluteal phase. In this study, we further characterized the OG-1 antigen. An immunohistochemical study showed that the OG-1 antigen was also expressed on endometrial glandular and stromal cells and on first trimester and term placental trophoblasts. The antigen purified from endometrium, chorionic villi, or placenta by immunoaffinity chromatography using the mAb OG-1 consisted of a 120-kilodalton (kDa) protein. Partial amino acid sequencing of the 120-kDa protein purified from placenta revealed that the 16 amino acids from the N-terminus were identical to those of the heavy chain of human integrin alpha 6, the molecular mass of which is reportedly 118-126 kDa. We examined the tissue distribution of integrins alpha 6, beta 1, and beta 4, because integrin alpha 6 forms heterodimers with integrins beta 1 or beta 4. Indirect immunofluorescence staining of various follicles and corpora lutea using two known antiintegrin alpha 6 monoclonal antibodies (450-30A1 and GoH3) showed that integrin alpha 6 was expressed on granulosa and large luteal cells in a profile similar to that of the OG-1 antigen. Integrin beta 1 was expressed on granulosa and large luteal cells, but integrin beta 4 was undetectable. Integrin beta 1 was also expressed on thecal and stromal cells. In term placentas, the OG-1 antigen and integrins alpha 6 and beta 4 were expressed on trophoblasts, whereas integrin beta 1 was expressed on villous capillary endothelia. These results indicate that the mAb OG-1 recognizes integrin alpha 6, and that integrin alpha 6 is a differentiation-related antigen of human GC, suggesting the involvement of integrins in human folliculogenesis and luteal formation.

Adult↗
PubMed1995

Amino acids and peptides. XXVI. Laminin-related peptide poly(ethylene glycol) hybrids and their inhibitory effect on experimental metastasis.

Laminin-related peptide poly(ethylene glycol) hybrid, Tyr-Ile-Gly-Ser-Arg-aminopoly(ethylene glycol) was prepared by the solution method and carboxylated poly(ethylene glycol)-Tyr-Ile-Gly-Ser-Arg was prepared by the solid phase method. Their inhibitory effects on experimental tumor metastasis were examined in mice. The inhibitory effect of Tyr-Ile-Gly-Ser-Arg was significantly potentiated by hybrid formation with poly(ethylene glycol) either at amino- or carboxyl terminals of the peptide. Of the hybrids, Tyr-Ile-Gly-Ser-Arg-amino(polyethylene glycol) #6000 hybrid exhibited about 10 times more potent anti-metastatic effect than the peptide itself. The inhibitory effect of a mixture of the carboxylated poly(ethylene glycol) hybrid and Arg-Gly-Asp-aminopoly(ethylene glycol) hybrid also exhibited an inhibitory effect.

Amino Acid Sequence↗
PubMed1995

18F-labeled octanoates as potential agents for cerebral fatty acid studies. The influence of 4-substitution and the fluorine position on biodistribution.

In order to understand the structural features that might lead to an in vivo radiotracer for studying cerebral fatty acid metabolism, 8-[18F]fluorooctanoate derivatives with methyl or gem-dimethyl branching at the C4 position have been prepared. 3-[18F]Fluoro- and 4-[18F]fluorooctanoic acid have also been synthesized for studying the influence of the fluorine position on the in vivo behavior of 18F-labeled octanoic acid analogs. Radiochemical synthesis was achieved by the nucleophilic displacement of a tosylate or mesylate precursor with [18F]fluoride ion. Tissue distribution studies in rats showed low cerebral uptakes of these 18F-labeled fatty acid analogs with poor brain-to-blood ratios. 3-[18F]Fluorooctanoic acid showed considerable defluorination, evident as a high bone activity level. The initial uptake of activity in the brain after injection of ethyl 8-[18F]fluoro-4-methyloctanoate and 4-[18F]-fluorooctanoic acid remained virtually unchanged over an extended time period, similar to that previously observed for the unbranched analogs, ethyl 8-[18F]fluorooctanoate and its free acid. In contrast, the 4-gem-dimethyl branched analog was rapidly and preferentially taken up by the liver. It was shown in the metabolite analysis that labeled metabolites produced from 8-[18F]fluoro-4-methyloctanoic acid were found in blood, and that they could enter the brain to a significant degree. Thus, the present studies showed that radioactivity retention in the brain in the case of the 4-methyl branched analog was mainly attributable to its radioactive metabolites.

Animals↗
PubMed1995

[Preparation of specific antiserum of secretin and its use in time-resolved fluoroimmunoassay].

We have prepared a specific anti-secretin antiserum and developed a sensitive time-relevant fluoroimmunoassay (TR-FIA) for secretin. An anti-secretin antiserum was produced in rabbit by immunization with synthetic secretin C-terminal 8 residue conjugate to chicken serum albumin as antigen. The TR-FIA was based on the competition between free secretin and biotinylated secretin as a tracer for rabbit anti-secretin antibodies on a goat anti-rabbit IgG antibody coated microtiter plate. After separation of bound and free fractions, a solution of europium (III) ion chelate labeled streptavidin (Eu-SA) was added to the biotinylated secretin bound on the microtiter plate. The microtiter plate was washed and then Eu-SA activity was measured by time-resolved fluorometry. In this TR-FIA, the measurable range of secretin was from 2.5 to 100 pg/assay and the specificity was less than 0.01% against other peptide hormones. For the measurement of secretin in the human plasma, a sample was required for the pretreatment in order to separate from interfering substances. The mean recovery of secretin using commercially reverse phase column was 80.2% (n = 11). The plasma secretin concentrations of normal subjects and those with various diseases could be measured by this proposed TR-FIA.

Animals↗
PubMed1995

[Enzyme structure and specific gene expression of gastric proton pump].

Progress in molecular biological studies on the H+/K(+)-ATPase (gastric proton pump) now enables us to discuss not only its subunit protein structures and catalysis but also the organizations of its subunit genes and their cell-specific transcription. The primary structures of the catalytic alpha and glycosylated beta subunits and their transmembrane topology are similar to those of the corresponding subunits of Na+/K(+)-ATPase. The exon/intron organizations of the genes for the H+/K(+)-ATPase alpha and beta subunits are closely similar to those of the corresponding subunits of Na+/K(+)-ATPase, suggesting that the alpha and beta subunit genes of the two ATPases were respectively derived from common ancestors. In contrast to ubiquitous Na+/K(+)-ATPase, the H+/K(+)-ATPase is expressed specifically in gastric parietal cells. Consistent with this fact, we found novel zinc finger proteins which are present in the gastric parietal cells and recognize a gastric sequence motif in the 5'-upstream regions of the H+/K(+)-ATPase alpha and beta subunit genes. The proteins are likely to play important roles in the transcriptional regulation of the parietal cell specific genes.

Amino Acid Sequence↗
PubMed1995

A unique case of renovascular hypertension caused by combined renal artery disease.

We present a unique case of renovascular hypertension due to combined renal artery disease in a 22-year-old woman. Renal angiography revealed renal artery stenosis with poststenotic dilatation and an aneurysm due to fibromuscular dysplasia in the left kidney, and a congenital arteriovenous fistula in the right kidney. The results of a captopril test and plasma renin sampling demonstrated that the renin-angiotensin-aldosterone system was stimulated in both kidneys, accounting for the hypertension in this patient. Almost all cases of renovascular hypertension are due to only one underlying renal artery disease. This is the first case of renovascular hypertension associated not only with renal artery stenosis and an aneurysm due to fibromuscular dysplasia, but also with a congenital arteriovenous fistula.

Adult↗
PubMed1995

Hypertrophic anterior falx artery associated with interhemispheric subdural empyema--Case report.

A 14-year-old boy presented with interhemispheric subdural empyema. Angiography demonstrated a hypertrophic anterior falx artery. He was treated with antibiotics and craniotomy to evacuate the lesion. The postoperative course was uneventful with no signs of neurological deficit. The abnormal artery was no longer visualized angiographically after the resolution of the empyema. Reactive appearance of the anterior falx artery is a pathognomonic sign of interhemispheric subdural empyema.

Adolescent↗
PubMed1995

[The effects of solid phase preparation on sensitivity of enzyme immunoassay].

The preparation of solid phase immobilized antibody or antigen was physical adsorption or chemical binding using coupling reagent such as glutalaldehyde etc. The concentration of antibody or antigen on solid phase was effective to sensitivity of enzyme immunoassay. When the nonspecific binding of enzyme conjugate to solid phase was minimized, the sensitivity of enzyme immunoassay will be succeed in higher.

Adsorption↗
PubMed1995

[The assay of enzyme activity in EIA--colorimetric, fluorometric and luminometric method].

The method of enzyme activity related in enzyme immunoassay was described. The detection methods were colorimetric, fluorometric and chemi- or bioluminometric assay for enzyme, and the sensitivity of three detection methods were compared. The order of detection limit was chemi- or bioluminometry > fluorometry > colorimetry. But it is important that the selection of detection method of enzyme will make fit on your desirable sensitivity of analysis.

Alkaline Phosphatase↗
PubMed1995

MR of pituitary metastasis in a patient with diabetes insipidus.

We present a case of acute-onset diabetes insipidus in a 69-year-old man who had been treated for lung cancer. T1-weighted MR images showed a thickened pituitary stalk and absence of the normal high intensity of the posterior pituitary lobe. Dynamic imaging demonstrated poor enhancement in the posterior lobe, whereas the anterior lobe was strongly enhanced. Autopsy revealed that metastatic tumor from lung cancer had infiltrated the posterior lobe as well as the pituitary stalk.

Aged↗
PubMed1995

[Prediction of postoperative pulmonary function using 99mTc-MAA perfusion lung SPECT].

In order to predict postoperative pulmonary function, 99mTc-MAA perfusion lung SPECT and spirometry were performed preoperatively in 52 patients with resectable primary lung cancer; 44 underwent lobectomy, eight pneumonectomy. Local pulmonary function (called local effective volume) was evaluated according to the degree of radionuclide distribution of each voxel in the SPECT images. The total effective volume was defined as the sum of the local effective volume, and the residual effective volume was the total effective volume excluding loss after operation. Predicted pulmonary function (VC and FEV1.0) was calculated by the following formula: Predicted value = preoperative value x percent of the residual effective volume. Postoperative pulmonary function was predicted in the same patients by means of 99mTc-MAA perfusion lung planar scintigraphy and X-ray CT. The patients were reinvestigated with spirometry at one and four months after surgery, and the values were compared with the predicted values. The correlations between the predicted values using SPECT and measured postoperative pulmonary function were highly significant (VC: r = 0.867, FEV1.0: r = 0.864 one month after operation; VC: r = 0.860, FEV1.0: r = 0.907 4 months after operation). The predicted values calculated using SPECT were accurate compared with the predicted values calculated using planar scintigraphy or X-ray CT. The patients with predicted FEV1.0 of less than 0.8 liter required home oxygen therapy. This method is valuable for the prediction of postoperative pulmonary function before the surgical procedure.

Adult↗
PubMed1995

[Pulmonary embolectomy for massive pulmonary embolism].

Surgical cases of massive pulmonary embolism remain rare in Japan. To discuss the surgical problems, clinical courses of 4 patients who underwent pulmonary embolectomy under cardiopulmonary bypass at our hospital for the last six years were reviewed. There were 2 men and 2 women; ranging from 41 to 72 years (mean age, 63 years), 1 of whom had deep venous thrombosis of the lower extremity as a predisposing factor. The initial disease recurred in 2 patients. Shock occurred in 3 patients preoperatively, 2 of whom had sudden syncope. Cardiac arrest occurred before and during pulmonary arteriography (PAG) in 1 patient. The systolic pulmonary arterial pressure rose to between 60 and 80 mmHg in all patients except for 1 of whom it was not measured. The diagnosis was established in 3 patients by PAG and clinically in the remaining recurrent patient. Thrombolysis was not effective in all patients, then pulmonary embolectomy was performed between four hours and five days after the onset of the disease. One patient with preoperative cardiac arrest died of low output syndrome and severe respiratory failure, but 3 survived with clinical improvement. Development of the prompt and noninvasive diagnostic procedure, rapid cardiopulmonary support in severe cases and an early decision to operate are required to improve the operative results. Partial resection of the lung was obliged due to massive endobronchial hemorrhage after embolectomy in 1 recurred patient. Compression of the lungs and embolectomy using a balloon catheter should be performed carefully to prevent injuring pulmonary arteries. Implantation of an inferior vena cava filter may be beneficial for the selected patient to prevent recurrence of the disease.

Adult↗