Search PubMed⌕ Search

Biomedical subjects

M Maeda

Publications and source records attributed to M Maeda.

At least 469 records · Page 26Linked to original sources
PubMed1997

Susceptibility of nude mice carrying the Fv-4 gene to Friend murine leukemia virus infection.

Fv-4 is a mouse gene that dominantly confers resistance to infection with Friend murine leukemia virus (F-MuLV) (S. Suzuki, Jpn. J. Exp. Med. 45:473-478, 1975). Despite complete resistance to ecotropic MuLV infection in mice carrying the Fv-4 gene, it is known that cells carrying the resistance gene in tissue culture do not always show resistance as extensive as that in vivo (H. Yoshikura and T. Odaka, JNCI 61:461-463, 1978). To investigate the immunological effect on resistance in vivo, we introduced the Fv-4 gene into BALB/c nude mice (Fv-4-/- nude[nu/nu]) by mating them with Fv-4 congenic BALB/c mice (Fv-4r/r nude+/+) and examined the susceptibility of the F2 progeny to F-MuLV. All BALB/c nude mice without the Fv-4 gene (Fv-4-/- nude[nu/nu]) were permissive to F-MuLV and developed erythroleukemia within 2 weeks after virus inoculation. The BALB/c nude mice with the Fv-4 gene (Fv-4r/r nude[nu/nu]) did not develop leukemia, and no or little virus was detected in the spleen 7 weeks after virus inoculation. The resistance to F-MuLV was dominant in (Fv-4 congenic BALB/c x BALB/c nude) F1 mice with the Fv-4r/- nude(nu/+) genotype as strictly as in (Fv-4 congenic BALB/c x BALB/c) F1 mice with the Fv-4r/- nude+/+ genotype. However, almost all BALB/c nude mice with the Fv-4r/- nude(nu/nu) genotype developed the disease within 7 weeks, and the virus was detected in all of their spleens even in the mice without leukemia. These results show that the resistance caused by the Fv-4 gene is recessive in nude mice and dominant in BALB/c mice. Some immunological effects, perhaps cell-mediated immunity, may play important roles in the resistance to F-MuLV infection in vivo in addition to the dosage effect of the Fv-4 product.

Animals↗
PubMed1997

cis-Acting inhibitory elements within the pol-env region of human T-cell leukemia virus type 1 possibly involved in viral persistence.

Human T-cell leukemia virus type 1 (HTLV-1) remains latent throughout the life of the carrier, with cells containing the provirus and viral gene expression efficiently down-regulated. On a molecular level, exactly how viruses are down-regulated in vivo remains unresolved. We described here the possibility that down-regulation results from the presence of inhibitory elements within the gag-env region of the provirus in fresh peripheral blood mononuclear cells from carriers. In vitro experiments then revealed that potent cis-acting inhibitory elements (CIEs) are indeed contained in two discrete fragments from the pol region and weaker ones in the env region. The effect of CIEs is relieved by the HTLV-1 posttranscriptional regulator Rex through binding to the Rex-responsive element (RxRE), suggesting that Rex might interfere with pre-mRNA degradation and/or activate the export of mRNA molecules harboring both of the inhibitory elements and RxRE on the same RNA molecule. Thus, we propose the hypothesis that such functions of CIEs may be involved in HTLV-1 persistence.

Cell Line↗
PubMed1997

Use of [3H]methylglucose and [14C]iodoantipyrine to determine kinetic parameters of glucose transport in rat brain.

Local maximal velocities of transport (Tmax) and the half-maximum transport constants (KT) for glucose transport across the blood-brain barrier have been determined in local regions of the brain in normal conscious rats. [14C]iodoantipyrine and [3H]methylglucose were infused together intravenously for 2 min in rats with plasma glucose concentrations maintained at different levels, and the time courses of the tracer levels in arterial blood were measured. Local 14C and 3H concentrations were then measured in tissue samples dissected from the frozen brains. By comparing the transport-limited uptake of [3H]methylglucose with the blood flow-limited uptake of [14C]iodoantipyrine, the value of m, a factor between 0 and 10 that accounts for diffusion and/or transport limitations, was derived, and from the equation, m = 1 - PS/F (where PS is capillary permeability-surface area product and F is cerebral blood flow), the permeability-capillary surface area for methylglucose was calculated (S. S. Kety. Pharmacol. Rev. 3: 1-41, 1951). Values for Tmax and KT for glucose were calculated by application of Michaelis-Menten kinetic relationships adapted for the competition for transport between glucose and methylglucose. Tmax was determined in three representative gray structures and one white structure of the brain: Tmax was 5.3 +/- 0.3 (SD) mumol.g-1.min-1 in the gray structures and 4.3 mumol.g-1.min-1 in the white structure. KT was 3.6 +/- 0.4 (SD) mM in the gray structures and 5.9 mM in the white structure. This approach allows the simultaneous determination of local values of Tmax and KT for glucose and the rates of blood flow in various regions of the brain in conscious animals.

3-O-Methylglucose↗
PubMed1997

Prognosis of Parkinson's disease in Japan. Tottori University Parkinson's Disease Epidemiology (TUPDE) Study Group.

Therapy for Parkinson's disease (PD) has been progressing. However, the prognosis for patients with PD is still unclear. We studied the course of PD in patients in the San-in Area of Japan over a long time period. The main purpose of this study was to see whether there was a difference in survival between PD patients and the general population. Information on 114 deceased PD patients, who died between 1989 and 1996, was collected from hospitals belonging to the Tottori University Parkinson's Disease Epidemiology Study Group. Although the duration of illness was prolonged, the survival of PD patients was still poorer than that of the general population. The most common cause of death was pneumonia. The main cause of death in young PD patients was also pneumonia. In order to improve the survival of PD patients, PD-related conditions should be treated more extensively, especially pneumonia.

Aged↗
PubMed1997

Laminin suppresses progesterone production by human luteinizing granulosa cells via interaction with integrin alpha 6 beta 1.

We previously raised a murine monoclonal antibody (mAb), OG-1, against human granulosa cells (GC) and reported that human GC express the OG-1 antigen with the highest immunoreactivity during the periovulatory phase. Later, we showed that the OG-1 antigen is identical to human integrin alpha 6, and that human GC express integrin alpha 6 beta 1, but not alpha 6 beta 4. In the present study, we examined the expression of laminin (LN), the ligand for integrin alpha 6 beta 1. Flow cytometry showed that LN was bound to the cell surface of some GC obtained from preovulatory follicles of patients undergoing in vitro fertilization. Immunohistochemistry showed that LN was detected between luteinizing GC in the early corpora lutea. To examine the effect of LN on steroidogenesis by human luteinizing GC, GC obtained from patients undergoing in vitro fertilization were cultured on mouse LN-coated or noncoated plastic dishes in medium containing 5% FCS for 24 h. In the absence or presence in hCG (1 IU/mL), GC cultured on LN-coated dishes produced 0.70- and 0.67-fold less progesterone than those on noncoated dishes, respectively (P < 0.05). We examined the effect of the interaction of integrin alpha 6 beta 1 and LN on steroidogenesis by human luteinizing GC. We cultured GC with 5 micrograms/mL of the anti-alpha 6 mAb GoH3, which inhibits the interaction between human integrin alpha 6 beta 1 and mouse LN, or with a control rat mAb (TER199) on mouse LN-coated dishes in serum-free medium for 24 h. In the absence or presence of hCG (1 IU/mL), GC cultured with GoH3 produced 1.97- and 1.94-fold more progesterone than the control cells (P < 0.01 and P < 0.05, respectively). In contrast, when GC were cultured on dishes coated with type IV collagen, progesterone production was not enhanced by GoH3. Furthermore, the anti-alpha 6 mAb OG-1, which does not inhibit the interaction between integrin alpha 6 beta 1 and LN, had no effect on the progesterone production by GC cultured on LN. These results indicate that LN suppresses the luteinization of human luteinizing GC via integrin alpha 6 beta 1 and that integrin alpha 6 beta 1 regulates the luteinization of human GC during the periovulatory phase.

Adult↗
PubMed1997

Amino acids and peptides. XXX. Preparation of Arg-Gly-Asp (RGD) hybrids with poly(ethylene glycol) analogs and their antimetastatic effect.

Hybrids of a fibronectin-related peptide[Arg-Gly-Asp (RGD)] with poly(ethylene glycol) (PEG) analogs were prepared by a simple and easy procedure. Two amino-PEG analogs were used as carriers for hybrid formation of the RGD. One was poly(oxyethylene)dipropylamine and the other was Jeffamine ED type, which has branched chains. RGD peptides were formed stepwise on PEG analogs by the diisopropylcarbodiimide method. The synthetic intermediates were easily purified by molecular-sieve gel chromatography and the final products were purified by molecular-sieve gel chromatography, followed by HPLC. This simple and easy preparation procedure using molecular-sieve gel chromatography for purification of synthetic intermediates is advantageous for the preparation of peptide-polymer hybrids. We found that PEG is stable to HF treatment at 0 degree C for 1 h. The inhibitory effect of the RGD hybrids on experimental metastasis of B16-BL6 was examined in mice. The Jeffamine type hybrid showed no inhibitory effect at the dose of 1 mg/mouse, but poly(oxyethylene)dipropylamine type hybrid was inhibitory at the same dose. The effect of the latter hybrid was about the same as that of 1 mg of RGD. One mg of the hybrid contains 0.18 mumol of RGD and 1 mg of RGD is 2.38 mumol. Thus it can be said that the inhibitory effect of RGD was potentiated by hybrid formation with poly(oxyethylene)diisopropylamine.

Animals↗
PubMed1997

[Differences between phthaleins and sulfonphthaleins].

Differences in color and molecular structure between phthalein-pigments and sulfonphthalein-pigments were investigated using X-ray crystallography and absorption spectrophotometry of their aqueous solutions. The molecular structure of sulfonefluorescein (H2+SF-) was determined as a zwitter ion, 2-(3-hydroxonio-6-hydroxy-3H-xanthen-9-yl)benzenesulfonate. The absorption spectra of H2+SF- demonstrated the dissociation profile of a dibasic acid, while those of fluorescein (H2FL) indicated a tribasic acid and further, at pH > 10, SF2- and FL2-, while at pH < 0, H2+SF- and H3+FL to be dominant. The spectra of H2+SF- were analyzed to obtain the values of pK1 and pK2 together with the spectrum of HSF-. Similarly, from the spectra of H3+FL the values of pK1, pK2 and pK3 together with the spectra of HFL- and H2FL were obtained. Further by adding 1/5 of the H3+FL spectrum to 2/15 of HFL- spectrum, an indicated spectrum as that of H2FL was obtained. From these results, the features of dissociation of H2SF- and H3+FL were estimated. The molecular structure of phenolsulfonphtalein (H2PS-) was determined as a zwitter-ion, alpha-(4-hydroxonio-2,5-cyclohexadiene-1-ylidene)-alpha- (4-hydroxyphenyl)-2-toluenesulfonate. The absorption spectra of H2PS- demonstrated that H2PS-, HPS- and PS2- became dominant at pH << 0, pH = 4 and pH > 11, respectively. On the contrary, phenolphthalein (H2PP) displayed only one type of absorption spectrum in the visual region, the shape of which was similar to that of PS2- while the molar extinction coefficient was smaller. The spectra were analyzed to obtain the values of pK1 = 9.05 and pK2 = 9.50. The spectra also demonstrated a slow addition reaction of OH- to PP2- and pK3 = 12 was obtained by measuring the absorbance after equilibration. From these results, the features of dissociation and coloration of H2+PS- and H2PP were estimated.

Color↗
PubMed1997

[Chemiluminescent assay for biological substances using lucigenin].

The chemiluminescent reaction of lucigenin with various biological substances has been studied. Chemiluminescence of lucigenin is produced by the addition of either hydrogen peroxide or organic reducing compounds to lucigenin in an alkaline solution. On the basis of these reaction, we have developed highly sensitive chemiluminescent methods for the detection of enzyme immunoassay, especially using alkaline phosphatase as a label enzyme, and also for HPLC of corticosteroids or p-nitrophenacyl esters of carboxylic acids. The detection limits of enzymes were 10(-19)-10(-20) mol per assay, corticosteroids and p-nitrophenacyl esters were 500 fmol per injection.

Acridines↗
PubMed1997

[Chemiluminescent enzyme immunoassay of cholecystokinin in rat plasma using an immuno-affinity column as a pretreatment].

The cholecystokinin (CCK) plasma concentration of a basal level in a normal rat was at a hardly detectable level (a few pg/ml) even using the highly sensitive chemiluminescent enzyme immunoassay. In this paper, we prepared an anti-CCK F(ab')2 fragment which was made by pepsin digestion from the anti-CCK antiserum. The anti-CCK F (ab')2 fragment was immobilized to the Sepharose 4B gel activated BrCN and packed to column. We have extracted and concentrated CCK in the rat plasma using this column and the CCK assayed by the chemiluminescent enzyme immunoassay (CL-EIA) of CCK. The immuno-affinity column extraction system was more accurate and precise than a reversed phase gel extraction system. The mean recovery of CCK from the rat pooled plasma using the immuno-affinity column was 62.2% (n = 12) by the proposed CL-EIA. The mean +/- S. E. (n = 3) of the CCK concentration in the fasted rat plasma is 3.54 +/- 0.10 pg/ml. The plasma CCK concentrations of normal rats and those of camostat administrated rats, could be measured by the proposed CL-EIA using the immuno-affinity column as a pretreatment.

Animals↗
PubMed1997

NMR spectroscopic analysis of sulfated beta-1,3-xylan and sulfation stereochemistry.

A novel sulfated beta-1,3-xylan product was synthesized from algal cell wall microfibril homoxylan by the N,N-dimethylformamide (DMF)-SO3 complex sulfation method. Antithrombin activity appeared in this product was 6.5 times higher than that of standard heparin. From the results of 1H- and 13C-NMR spectroscopic analyses by DQF-COSY and HMQC and an infrared spectroscopic analysis, it was revealed that the ordered structure of beta-1,3-xylan as a triple helix had decayed and the resulting conformational changes had been caused by the sulfation reaction. The sulfated positions on the C-4 hydroxyl groups of the xylose residues were determined from 13C-NMR chemical shifts, and it was found that regioselective sulfation had occurred predominantly with the C-4 secondary hydroxyl groups to produce a mono-substituent. Another type of sulfation of beta-1,4-xylan that showed no regioselectivity is considered to have been due to the different conformation of both xylans chains such as the triple helix in beta-1,3-xylan and the double straight chain like cellulose in beta-1,4-xylan. Therefore, the different type of regioselective sulfation of beta-1,3- and beta-1,4-xylan was caused by the difference in steric hindrance due to these conformations. These different types of regioselective sulfation with different linkage positions are also discussed for the secondary hydroxyl groups in beta-1,3- and beta-1,4-glucan after chemoselective sulfation of the C-6 primary hydroxyl groups.

Antithrombins↗
PubMed1997

Bradykinin-induced airway contraction in two lines of guinea pigs with congenitally different airway sensitivity.

The airway responsiveness to bradykinin (0.1, 1 and 10 microg/kg, i.v.) was examined in two lines of guinea pigs, BHS (bronchial hypersensitive) and BHR (bronchial hyposensitive) lines, with different airway sensitivity to inhalation of acetylcholine (ACh)-aerosol. Normal Hartley strain guinea pigs were used as a control group. The airway contraction was measured by recording intratracheal pressure (P[IT]) and respiratory airflow (V) under the condition of artificial ventilation in anesthetized guinea pigs. The results show airway responsiveness to bradykinin in BHS guinea pigs to be significantly greater than in BHR and normal Hartley strain guinea pigs.

Airway Resistance↗
PubMed1997

Relationship between caffeine-induced ocular hypertension and ultrastructure changes of non-pigmented ciliary epithelial cells in rats.

The purpose of this study was to morphologically assess a possible mechanism for caffeine-induced ocular hypertension. Taking into consideration the relationship between the secretion of aqueous humor and the ultrastructure of the ciliary body, the time course of the morphological features in the ciliary epithelium when caffeine was administered intravenously to male Wistar rats was investigated by electron-microscopy. These morphological findings were also compared with the changes in the intraocular pressure (IOP). A significant increase in IOP was noted 15 min and 1 hr after a single dosing of caffeine alone. This change disappeared in all animals within 2 hr after dosing. The IOP in the animals receiving caffeine and the beta-blocker befunolol, which lowers the IOP by inhibiting aqueous humor secretion, decreased significantly from 15 min after dosing, and this change persisted 2 hr after dosing. In electron-microscopy 15 min and/or 1 hr after dosing with caffeine, a slight dilatation in the lateral intercellular spaces near the basement membrane of the non-pigmented ciliary epithelium was observed and the interdigitations between the non-pigmented epithelial cells were intact. Reversal of these changes was observed 2 hr after dosing. On the other hand, the lateral intercellular spaces between the non-pigmented epithelial cells were markedly dilated and the interdigitations were disorganized following dosing with caffeine alone and in combination with befunolol. These results described here indicate that the intravenous administration of caffeine causes ocular hypertension and also changes in the non-pigmented ciliary epithelium, suggesting an enhancement of aqueous humor transportation. This paradigm in the rat is considered to be useful to further assess caffeine-induced ocular hypertension and for use as an animal model in glaucoma research associated with an aqueous humor secretion.

Adrenergic beta-Antagonists↗
PubMed1997

Thallium-201 single photon emission computed tomography imaging of meningioma cells in hyperostosis.

Hyperostosis is a well-known bony reaction associated with meningioma. However, it is difficult to determine preoperatively whether meningioma cells have invaded the bone, and if so, the extent of tumor invasion. Preoperative thallium-201 chloride single photon emission computed tomography (201Tl SPECT) was performed in four patients with meningioma and hyperostosis. The presence of meningioma cells in bone biopsy specimens was also investigated using standard histological techniques. 201Tl SPECT revealed increased uptake in three of the four patients. Biopsy specimens from these three patients revealed invasion of the bony lesions by meningioma cells in accordance with the 201Tl SPECT findings. 201Tl SPECT found no abnormal uptake in the other patient, in which there was also no histological evidence of tumor invasion of bone. Preoperative 201Tl SPECT can provide information on bone invasion by meningioma, which will facilitate preoperative planning of the extent of bony resection required at meningioma surgery.

Adolescent↗
PubMed1997

Intraventricular, cystic, atypical meningioma.

A 37-year-old male presented with a very rare cystic meningioma in the trigone of the left lateral ventricle. Neurological examination revealed mild conduction aphasia and right hemisensory disturbance. Computed tomography and magnetic resonance imaging showed a solid, enhancing tumor in the left trigone which had multiple cystic components located anteriorly and superiorly. The tumor was totally resected via a parietal, transventricular approach. Histological examination revealed an atypical meningioma with cellular pleomorphism and prominent nucleoli. Both the solid component and the cyst wall consisted of tumor cells.

Adult↗
PubMed1997

[Successful repair of combined cardiac rupture and septal perforation after myocardial infarction].

A 78-year-old woman was operated on with a diagnosis of oozing-type cardiac rupture after an acute anteroseptal myocardial infarction. Pericardial drainage was performed and hemostasis was obtained by dressing with local hemostatics. As hemodynamics improved, elevation of pulmonary artery pressure and a step-up in oxygen concentration in the pulmonary artery from a Swan-Ganz catheter sample appeared. A left-to-right shunt was observed in the operative field with color Doppler echocardiography and a diagnosis of ventricular septal perforation (VSP) was made. Subsequently, intracavitary repair with two sheets of equine pericardial patch, sutured using interrupted mattress sutures with felt pledgets, was performed. Her early course after operation was satisfactory in spite of a small residual shunt. However, thirty-one days later she was returned to surgery because of an increasing residual shunt. Looseness of several interrupted mattress sutures and thrombus adherent to the internal surface of the pericardial patch were observed. The thrombus was removed and the patch was reattached using both interrupted mattress sutures with felt pledgets and continuous suture. She had an uneventful recovery thereafter. As double rupture is not a rare complication after myocardial infarction, a careful hemodynamic examination is necessary and important in the diagnosis and treatment of cardiac rupture. We consider that interrupted mattress sutures are a better technique for early repair of the VSP to reduce a risk of residual shunt due to the weakness and unclear border of infarcted myocardial tissue, and continuous suture is acceptable to repair the VSP 3 to 4 weeks later after infarction. Long-term anticoagulant therapy is necessary after intracavitary repair using equine pericardial patch.

Aged↗
PubMed1997

Solitary and multiple pyogenic liver abscesses: characteristics of the patients and efficacy of percutaneous drainage.

OBJECTIVES: Although percutaneous drainage has emerged as one of the first line of therapies for pyogenic liver abscesses, the presence of multiple abscesses may warrant surgical drainage, which remains controversial in the literature. We studied whether the multiplicity of the lesions influences the outcome of the treatment. METHODS: Ultrasonography-guided percutaneous drainage was carried out in 48 patients with pyogenic liver abscesses. The abscesses were solitary in 38 patients and multiple (two to seven lesions) in 10 patients. Clinical characteristics and the efficacy of the treatment were compared between these two groups. RESULTS: Biliary diseases and malignancies were more frequently observed in the solitary cases than multiple cases. A past history of surgery for cholelithiasis was seen exclusively in the multiple cases. E. coli was more frequently cultured from the abscesses in the multiple cases. Three of the multiple cases required more than a single catheter. All of the multiple cases and 36 of the 38 solitary cases were successfully treated. Two patients died of biliary peritonitis as a complication of the procedure, and three died of other underlining diseases. CONCLUSION: Ultrasonography-guided percutaneous drainage is effective even in patients with multiple pyogenic liver abscesses by adding catheters to obtain sufficient drainage.

Adult↗
PubMed1997

[Assessment of radiotherapy effects on brain tumors by dynamic susceptibility contrast MR imaging].

Dynamic susceptibility contrast MR imaging(DSC MRI) was performed on eleven patients with brain tumors before and after radiotherapy. Their confirmed diagnoses were as follows: hemangioendothelioma(n = 1), meningioma(n = 1), low grade astrocytoma(n = 1), glioblastoma(n = 2), and brain metastasis(n = 6). The purpose of this study is to determine whether this technique is clinically useful for monitoring radiotherapeutic effect on brain tumors. Region of interest(ROI) analyses were performed on both the brain tumor and the contralateral normal area to evaluate the therapeutic effect semiquantitatively. The calculated subtraction images, rCBV maps, were also produced for the visual evaluation of the change of tumor vascular beds. The results showed that DSC MRI was clinically useful because of the capability to offer additional functional information.

Adult↗