Biomedical subjects

M Maeda

Publications and source records attributed to M Maeda.

At least 145 records · Page 8Linked to original sources

PubMed2001

Amino acids and peptides. XXXVIII. Facile synthesis of laminin-related peptide-poly(ethylene glycol) hybrids by the solid phase method.

Poly(ethylene glycol) (PEG) has been studied as a drug-carrier for proteins, but not for small peptides. Laminin, a cell adhesive protein, has Tyr-Ile-Gly-Ser-Arg (YIGSR) sequence and peptides containing this sequence inhibit experimental metastasis. We have studied PEG hybrids of YIGSR and other small laminin-related peptides. In a previous paper, we reported preparation of YIGSR-PEG hybrids by combination of the solid phase method and the solution method, but the synthetic procedure was problematic. Here we report a facile synthesis of PEG hybrids of YIGSR (PEG-YIGSR, YIGSR-PEG, PEG-YIGSR-PEG) by the solid phase method.

Animals↗

PubMed2001

Usefulness of bronchoalveolar lavage for the diagnosis and treatment of refractory pneumonia in a patient with Kostmann syndrome, a severe congenital neutropenia.

UNLABELLED: An 11-year-old girl with Kostmann syndrome developed refractory pneumonia. Culture of oral discharge, throat-swab specimens, and blood could not identity the causative organism, and systemic antimicrobial therapy failed to achieve improvement. We then performed diagnostic bronchoalveolar lavage (BAL) and culture of BAL fluid (BALF) yielded Pseudomonas aeruginosa. Therapeutic BAL using gentamicin produced a striking improvement of her pneumonia. CONCLUSION: In immunocompromised children with pneumonia, BAL helps to identify the causative organism. If the patient is unresponsive to systemic antimicrobial therapy, BAL using antimicrobial agents is also worth trying.

Bronchoalveolar Lavage↗

PubMed2001

Effects of estrous cycle on the mouse kidney morphology.

Although mice kidney morphology shows various sexual dimorphisms, the effect of the estrous cycle has not previously been discussed. In this study, we investigated the effects of the estrous cycle on kidney morphology, including renin-positive areas, of female DBA/2 mice. No effects were confirmed in most of the histometrical parameters, however, the percentage of the renal corpuscles in which cuboidal epithelium covered under 50% of the parietal layer was significantly higher during estrus compared to that during anestrus.

Animals↗

PubMed2001

Isolation and identification of pathogenic strains of Streptomyces acidiscabies from netted scab lesions of potato tubers in Hokkaido (Japan).

A relatively homogeneous group of streptomycete isolates was obtained from netted scab lesions of potato tubers collected from a potato field in Hokkaido, Japan. Based on 55 phenotypic data of 72 Streptomyces strains selected from these isolated together with spectral data on their soluble pigments and with data of a PCR analysis, using species specific primers, these netted scab causing pathogenic organisms were identified as S. acidiscabies. S. acidiscabies had previously been isolated from deep (common) scab lesions in the USA and reported as thaxtomin A producer. In contrast, our S. acidiscabies strains were not able to induce deep scab symptoms on potato minitubers in pot test, did not produce the phytotoxin thaxtomin A and did not contain the pathogenicity related gene, nec-1.

Bacterial Proteins↗

PubMed2001

Life-cycle toxicity of 4-nonylphenol to medaka (Oryzias latipes).

We studied the chronic effects of 4-nonylphenol (4-NP) on reproductive status of medaka (Oryzias latipes) over two generations of continuous exposure. The exposure study of the parental (F0) medaka was begun on embryos within 24 h postfertilization and continued with monitoring through embryological development, hatching, posthatch survival, growth, sexual differentiation, and reproduction under flow-through exposures to mean measured 4-NP concentrations of 4.2, 8.2, 17.7, 51.5, and 183 microg/L for up to 104 d. Eggs spawned from the F0 fish at 102 and 103 d posthatch were also examined for hatchability, survival after hatching, growth, and sexual differentiation until 60 d posthatch. The 183-microg/L treatment significantly reduced the embryo survival and swim-up success of the F0 fish. The cumulative mortality after swim-up of the F0 fish exposed to 17.7 and 51.5 microg/L were significantly higher than the control mortality. No concentration-related effect of 4-NP was observed on the growth of surviving F0 fish at 60 d posthatch. However, the sex ratio estimated from the appearance of their secondary sex characteristics was skewed toward female in the 51.5-microg/L treatment. Additionally, gonadal histology showed that 20% of the fish in the 17.7-microg/L treatment and 40% in the 51.5-microg/L treatment had testis-ova, indicating that 4-NP affects the gonadal development and survival of medaka at similar concentrations in juveniles. The sex ratio of the F0 fish in the 51.5-microg/L treatment was completely skewed toward female; subsequently, the effects on fecundity and fertility in this generation were monitored at mean measured concentrations of 4.2, 8.2, and 17.7 microg/L from 71 to 103 d posthatch. Fecundity was unaffected by any of the treatments examined. The mean fertility in the 17.7-microg/L treatment was reduced to 76% of that in the controls, although no statistically significant differences were determined. Overall, these results indicate that the lowest-observed-effect concentration (LOEC) and no-observed-effect concentration (NOEC) of 4-NP through the life cycle of the F0 medaka were 17.7 and 8.2 microg/L, respectively. In the F1 medaka, no significant effects were observed on hatching success, posthatch mortality, or growth, but sexual differentiation at 60 d posthatch was affected. Induction of testis-ova in the gonads of the F1 fish was observed in both the 8.2- and the 17.7-microg/L concentrations. The results indicate that 4-NP can have significant effects on reproductive potential of medaka at concentrations as low as 17.7 microg/L.

Animals↗

PubMed2001

Electrochemical sensing for the determination of activated cyclic AMP-dependent protein kinase.

A novel electrochemical system has been developed for monitoring the cyclic AMP-dependent protein kinase (PKA) activity. In this method, PKA activity was monitored as the change in the redox current of a ferrocene-pendant PKA substrate peptide (Fe-LRRASLG) on a gold electrode, which had been modified with thioctic acid, using cyclic voltammetry. The phosphrylation of the ferrocene-pendant substrate with PKA changed the net charge from +1 to -1. This caused a decrease in the redox current of the ferrocene unit due to an electrostatic repulsion between the substrate and the anionic surface of the electrode. We expect that this method is potentially useful for monitoring the enzyme activity in medical or pharmacological fields.

Biosensing Techniques↗

PubMed2001

Novel biosensor for the rapid measurement of estrogen based on a ligand-receptor interaction.

A bioaffinity sensor was developed aiming at the detection of estrogen. This biosensor system is based on the specific binding of estrogen to its receptor immobilized on a gold disk electrode. The recombinant DNA encoding human estrogen receptor ligand-binding domain was expressed in bacteria using the histidine-tag fusion system. The expression of the fusion protein was under control of a bacteriophage T7 promoter, and the protein was purified under native conditions by affinity chromatography, which is based on a specific interaction between a histidine-tag, located in the N-terminus of the protein, and the Ni(II) chelate adsorbent. The protein was immobilized on an Au-electrode with Ni(II)-mediated chemisorption using a histidine tag and thiol-modified iminodiacetic acid. Cyclic voltammetric measurements showed that the reversible electrochemical reaction of a ferrocyanide/ferricyanide redox couple was suppressed by the presence of estrogen in a concentration-dependent manner. It seems reasonable to suppose that the electrostatic property of the protein layer on the electrode surface was altered by complexation with estrogen. These data suggest that this biosensor is applicable to the evaluation binding activities of the chemicals toward the human estrogen receptor.

Biosensing Techniques↗

PubMed2001

Reversible posterior leukoencephalopathy syndrome in a patient with hypertensive encephalopathy--case report.

A 58-year-old male presented with reversible posterior leukoencephalopathy syndrome (RPLS) manifesting as headache, papilledema, and renal hypertension. T2-weighted magnetic resonance (MR) imaging showed hyperintensity lesions in the medulla, pons, bilateral thalami, and bilateral deep white matter of the parieto-occipital lobes. The pons was swollen. Diffusion-weighted MR imaging did not show increased intensity in these lesions. The lesions disappeared with improvement of clinical symptoms after treatment for hypertension. These findings suggested the lesions were vasogenic edema and the diagnosis was RPLS. T2-weighted and diffusion-weighted MR imaging are useful modalities to differentiate RPLS from other central nervous system abnormalities such as infarction, multiple sclerosis, and central pontine myelinolysis. The clinical and neuroradiological findings of RPLS can be reversed by timely initiation of treatment for the causative factor.

Brain↗

PubMed2001

Surgical treatment of chronic subdural hematoma in 500 consecutive cases: clinical characteristics, surgical outcome, complications, and recurrence rate.

Chronic subdural hematoma (CSDH) is one of the most common clinical entities in daily neurosurgical practice. The diagnosis and treatment are well established, but recurrence, complications, and factors related to these problems, especially in the elderly, are not completely understood. This study evaluated the clinical features, radiological findings, and surgical results in a large series of the patients treated at the same institution. 500 consecutive patients (359 men and 141 women) with CSDH were treated by burr hole craniostomy with closed system drainage from January 1987 through February 1999. Causes, clinical and computed tomographic findings, surgical results, re-expansion of brain after surgery, and hematoma recurrence were statistically analyzed to elucidate the potential risks of CSDH. Most patients (89.4%) had good recovery, 8.4% showed no change, and 2.2% worsened. Six patients (1.2%) died, three due to disseminated intravascular coagulation. Recurrence of hematoma was recognized in 49 patients (9.8%), at 1 to 8 weeks (3.5 +/- 1.9 weeks) after the first operation. The brain re-expansion rate at one week after operation was 45.0 +/- 21.4% in patients with hematoma recurrence and significantly lower than 55.3 +/- 19.1% in patients without recurrence (p < 0.001). Old age, pre-existing cerebral infarction, and persistence of subdural air after surgery were significantly correlated with poor brain re-expansion (p < 0.001). Twenty-seven patients (5.4%) suffered postoperative complications, of which 13 cases were acute subdural hematoma caused by incomplete hemostasis of the scalp wound and four cases were tension pneumocephalus. Careful hemostasis and complete replacement of subdural hematoma by normal saline to prevent influx of air into the subdural space will further improve the surgical outcome for patients with CSDH.

Adolescent↗

PubMed2001

Metastatic brainstem tumor manifesting as hearing disturbance--case report.

A 53-year-old male, who had undergone a left upper lung lobectomy for cancer 2 years previously, presented with metastatic brainstem tumor manifesting as hearing disturbance. At first an otorhinolaryngologist treated him for senile sensorineural hearing disturbance. However, he suffered gait ataxia and was referred to our department. On admission, neurological examination found mild cerebellar ataxia on the left and gait unsteadiness. Neurootological analysis revealed central-type sensorineural hearing disturbance on the left both in the pure tone audiogram and speech discrimination test. Neuroimaging studies revealed a ring-like enhanced mass centered in the ventral left middle cerebellar peduncle, partly extending to the inferior cerebellar peduncle. Peritumoral edema extending to the ipsilateral cochlear nucleus was recognized. He underwent surgery via a left lateral suboccipital transcondylar approach. The histological diagnosis was adenocarcinoma identical with the primary lung cancer. Intra-axial brainstem metastatic lesion can be a cause of hearing disturbance, so should be included in the differential diagnosis for a patient complaining of hearing disturbance, especially with a past history of cancer.

Adenocarcinoma↗

PubMed2001

Nocardia brasiliensis infection seen on grafted skin of the dorsum of a foot.

For the past 4 years a 23 y-old female has noticed erythema on the dorsum of the right foot, where skin was grafted due to a traffic accident 20 years ago. She visited the Department of Dermatology of Gifu Prefectural Hospital on Oct. 19, 1998; her general health was good. Physical examination disclosed a swelling with erythema, papules and pustules on the dorsum of the right foot. The results of routine laboratory investigations were within normal limits except for the white blood cell count (11,300/mm(3)), blood sediment rate (25 mm/hrs), C reactive protein (1.21) and rheumatoid factor (x 16.6). Several yellowish and verrucous or wrinkled colonies were grown on Sabourauds agar culture from the biopsied specimen of the foot. Histopathological features showed epidermal hyperplasia with elongation of rete ridges and granulomatous changes in the dermis; many mononuclear and giant cells were present, and several positive fine filamentous and irregularly branching structures with PAS and Grocott stains were seen in the granulomatous nests. Both clinical and histopathological features led to speculation of Nocardia infection, and Nocardia brasiliensis was determined. The patient was treated by surgical total resection including the grafted skin. Although a soybean-sized nodule was seen on the border of the skin-graft of the foot three months later, there was no recurrence after the local resection.

Adult↗

PubMed2001

[A case of central nervous system anomalies (agenesis of corpus callosum, colpocephaly, hydrocephalus, congenital dermal sinus) associated with congenital heart disease(double-outlet right ventricle, complete endocardial cushion defect, atrial septal defect, pulmonary arterial stenosis, patent ductus arteriosus)].

A case of central nervous system anomalies(agenesis of corpus callosum, colpocephaly, hydrocephalus, congenital dermal sinus) associated with congenital heart disease(double-outlet right ventricle, complete endocardial cushion defect, atrial septal defect, pulmonary arterial stenosis, patent ductus arteriosus) is reported. Female patient had been already diagnosed as hydrocephalus during pregnancy and ventricular drainage was performed soon after the delivery. Prostaglandin E 1 was also applied for heart disease, but saturation of O2 decreased to 80% on arterial blood gas analysis. Blalock-Taussig operation and ligation of ductus arteriosus was done 41 days after the delivery and ventricle-peritoneal shunt was also made for the progressive hydrocephalus on the same day. Chromosome analysis showed no abnormality. The genesis of this complicated brain and heart anomaly is discussed from the viewpoint of neural crest cell abnormality.

Abnormalities, Multiple↗

PubMed2001

Arterial hyperintensity on fast fluid-attenuated inversion recovery images: a subtle finding for hyperacute stroke undetected by diffusion-weighted MR imaging.

BACKGROUND AND PURPOSE: Diffusion-weighted MR imaging is generally acknowledged to be more sensitive in detecting acute stroke than is conventional MR imaging. Our purpose in the present study was to evaluate the utility of fast fluid-attenuated inversion recovery (FLAIR) MR imaging compared with that of diffusion-weighted MR imaging for the diagnosis of hyperacute stroke. METHODS: We reviewed patient records and cerebral MR images from all patients in a 13-month period from whom diffusion-weighted and fast-FLAIR imaging were obtained within 6 hours after symptom onset (n = 11). Special attention was paid to the presence or absence of arterial hyperintensity on FLAIR images and abnormally high-signal regions on diffusion-weighted images in the affected vascular territories. RESULTS: Arterial hyperintensity was found in eight of 11 patients, all of whom had embolic or thrombotic infarctions with middle cerebral arterial (MCA) distribution. Arterial hyperintensity was negative in the remaining three patients; the vascular territories were the posterior circulation region in two of these patients and the MCA region in one, and the types of infarction in these same patients were lacunar in two and embolic in one. Regions with high-signal diffusion abnormalities relevant to the patients' symptoms were found in 10 of 11 patients. One patient showed no diffusion abnormalities but the presence of arterial hyperintensity in the affected MCA territory on the initial MR examination, and manifested embolic infarction along with arterial hyperintensity on the initial FLAIR image. CONCLUSION: Although diffusion-weighted MR imaging is highly sensitive to stroke, diffusion-weighted MR imaging alone may not rule out a possible infarction. Arterial hyperintensity on FLAIR images can precede diffusion abnormalities and may provide a clue to the early detection of impending infarction.

Aged↗

PubMed2001

Plasma levels of syndecan-4 (ryudocan) are elevated in patients with acute myocardial infarction.

Syndecan-4 (ryudocan) is a cell-surface heparan sulfate proteoglycan, which plays an important role in a variety of biological functions including regulation of blood coagulation. cell adhesion, and cell growth. In this study, we measured plasma levels of syndecan-4 in patients with acute myocardial infarction using an enzyme-immunoassay, and found that they were extremely high, with a peak of average (10.5 +/- 5.6 ng/ml, 2 weeks after onset), as compared with those in normal subjects (0.078 +/- 0.030 ng/ml) (p < 0.001). We also observed a distinct expression of syndecan-4 in the repair region of the damaged cardiac tissues with infarction, but not in intact region, by immunohistochemical analysis. To clarify the mechanism of syndecan-4 induction, we investigated the hypoxia effect on its expression, and found that hypoxia treatment up-regulated the gene expression of syndecan-4 in various types of cells. Taken together, it is suggested that syndecan-4 is induced by hypoxia stimuli in ischemic heart tissues, and may function as a tissue-repair molecule via biological mediators such as heparin-binding growth factors.

Adult↗

PubMed2001

[Extraction of di-2-ethylhexyl phthalate from a cardiopulmonary bypass circuit].

We measured levels of di-2-ethylhexyl phthalate (DEHP) in a priming solution of a cardiopulmonary bypass circuit. The circuit consisted of a venous reservoir, an oxygenator, and polyvinyl chloride (PVC) tubes. Eight circuits were used in this study. In 4 circuits a heparin-coating PVC tube was used and, in the others, a non-coating PVC tube. After they were primed with 1,500 ml of saline, the saline was circulated for 30 minutes at a rate of 6 l/min at 42 degrees C. Another four samples were collected directly from the saline in a polyethylene container as a control. Then the concentrations of DEHP in them were determined by means of gas chromatography. No detectable DEHP was found in controls. But, a small amount was detected in the saline from the circuits (2.75 +/- 4.27 ppb, and 3.75 +/- 4.99 ppb, respectively). DEHP was considered to be leached from the circuit to the priming solution because the tubes were made of PVC containing DEHP as a plasticizer. We suppose the DEHP concentration is probably at a safe level. However, the data on the endocrinologically toxic level of blood DEHP are insufficient. Therefore, the use of plastic in a circuit may require closer scrutiny to determine whether DEHP leached from PVC contributes to exposure to xenoestrogens.

Cardiopulmonary Bypass↗

PubMed2001

[A case of retroperitoneal malignant fibrous histiocytoma with marked response to cisplatin, ifosfamide and doxorubicin].

A 61-year-old man was admitted to our hospital in December 1994 for a suspected retroperitoneal tumor. Systemic imaging investigations demonstrated retroperitoneal solid tumor, which was diagnosed as malignant fibrous histiocytoma (MFH) by immunohistochemistry for alpha 1-antitrypsin. In March 1995, he was treated with 3 courses of systemic chemotherapy with cisplatin, ifosfamide and doxorubicin followed by the same therapy in March 1996, without serious side effects. MFH is known to be resistant to ordinary chemotherapy. However, the CT showed a marked decrease in the size of the tumor, and the tumor disappeared within 2 months after the first treatment. The patient also recovered rapidly from abdominal pain, for which complete remission has been achieved for more than 5 years. The present chemotherapy may be an effective treatment for retroperitoneal MFH.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2001

[A case of cardiac myxoma with multiple brain hemorrhage].

A case of cardiac myxoma with multiple brain hemorrhage is reported. A 57-year-old male had complained of lower abdominal pain, diarrhea and fever for 3 days. On admission, he was in a condition of disseminated intravascular coagulation and sepsis. An abdominal CT scan showed infarction in the right kidney and spleen and an echocardiogram also showed myxoma in the left atrium. Although he presented no neurological symptoms, the brain CT showed multiple brain hemorrhage in the bilateral brain hemispheres. Total resection of the tumor was carried out for the improvement of the patient's general condition. Vimentin, S-100 protein and neuron specific enolase was positive in immunological staining and the pathological diagnosis was myxoma. Postoperative recovery of consciousness was poor and left hemiparesis developed. CT showed the increase of hematoma but angiography showed no cerebral aneurysm. The symptoms improved with conservative therapy. However the enhanced lesion remained in the right parietal lobe and an operation was performed 5 months later. The myxoma cell could not be found in the pathological examination, so tumor embolism, cerebral infarction, hemorrhagic infarction due to DIC, hematoma enlargement caused by heparinization during operation were suspected to have occurred in this order without tumor growth.

Brain↗

PubMed2001

[Evaluation for factors associated to early tracheal extubation after coronary artery bypass grafting].

Recent studies suggest that early tracheal extubation after coronary artery bypass grafting (CABG) may reduce intensive care unit use and cost. During recent two years, 96 patients were underwent CABG under cardiopulmonary bypass by low-dose fentanyl and isoflurane anesthesia. We compared two groups of patients for evaluation of factors associated to early tracheal extubation. 47 cases (Group A) were extubated within six hours (average 4.4 hrs) following operation, and 26 cases (Group B) were extubated later than twelve hours (average 57.5 hrs). It is suggested that emergency cases, female, elderly patients, dysfunction of kidney and long operation time associated to late extubation. But early extubation after CABG does not increase perioperative morbidity except for the cases that fell in low cardiac output syndrome or postoperative respiratory complications.

Adult↗