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Biomedical subjects

S Ebihara

Publications and source records attributed to S Ebihara.

At least 37 records · Page 2Linked to original sources

Photoinduced graft polymerization of 2-methacryloyloxyethyl phosphorylcholine on polyethylene membrane surface for obtaining blood cell adhesion resistance.

Phospholipid polymer, poly[2-methacryloyloxyethyl phosphorylcholine (MPC)], was grafted with polyethylene (PE) membrane using photoinduced polymerization technique to make the membrane resistant to cell adhesion. The water contact angle on the PE membrane grafted with poly(MPC) decreased with an increase in the photopolymerization time. This decrease corresponded to the increase in the amount of poly(MPC) grafted on the PE surface. The same graft polymerization procedure was applied using other hydrophilic monomers, such as acrylamide (AAm), N-vinylpyrrolidone (VPy) and methacryloyl poly(ethylene glycol) (MPEG). These monomers were also polymerized to form grafted chains on the PE membrane, and the grafting was confirmed with X-ray photoelectron spectroscopy. Analysis of amount and distribution of plasma proteins at the plasma-contacting surface of the original and the modified PE membranes were analyzed using immunogold assay. The grafting of poly(MPC) and poly(VPy) on PE membrane reduced the plasma protein adsorption significantly compared with that on the original PE membrane. However, the PE membranes grafted with poly(AAm) or poly(MPEG) did not show any effects on protein adsorption. Platelet adhesion on the original and modified PE membranes from platelet-rich plasma was also examined. A large number of platelets adhered and activated on the original PE membrane. Grafting with poly(AAm) did not suppress platelet adhesion, but grafting with poly(MPC) or poly(VPy) on the PE membrane was effective in preventing platelet adhesion. It is concluded that the introduction of the phosphorylcholine group on the surface could decrease the cell adhesion to substrate polymer.

Journal Article↗

Differential effects of dystrophin and utrophin gene transfer in immunocompetent muscular dystrophy (mdx) mice.

Duchenne muscular dystrophy (DMD) is a fatal disease caused by defects in the gene encoding dystrophin. Dystrophin is a cytoskeletal protein, which together with its associated protein complex, helps to protect the sarcolemma from mechanical stresses associated with muscle contraction. Gene therapy efforts aimed at supplying a normal dystrophin gene to DMD muscles could be hampered by host immune system recognition of dystrophin as a "foreign" protein. In contrast, a closely related protein called utrophin is not foreign to DMD patients and is able to compensate for dystrophin deficiency when overexpressed throughout development in transgenic mice. However, the issue of which of the two candidate molecules is superior for DMD therapy has remained an open question. In this study, dystrophin and utrophin gene transfer effects on dystrophic muscle function were directly compared in the murine (mdx) model of DMD using E1/E3-deleted adenovirus vectors containing either a dystrophin (AdV-Dys) or a utrophin (AdV-Utr) transgene. In immunologically immature neonatal animals, AdV-Dys and AdV-Utr improved tibialis anterior muscle histopathology, force-generating capacity, and the ability to resist injury caused by high-stress contractions to an equivalent degree. By contrast, only AdV-Utr was able to achieve significant improvement in force generation and the ability to resist stress-induced injury in the soleus muscle of immunocompetent mature mdx animals. In addition, in mature mdx mice, there was significantly greater transgene persistence and reduced inflammation with utrophin compared to dystrophin gene transfer. We conclude that dystrophin and utrophin are largely equivalent in their intrinsic abilities to prevent the development of muscle necrosis and weakness when expressed in neonatal mdx animals with an immature immune system. However, because immunity against dystrophin places an important limitation on the efficacy of dystrophin gene replacement in an immunocompetent mature host, the use of utrophin as an alternative to dystrophin gene transfer in this setting appears to offer a significant therapeutic advantage.

Adenoviridae↗

Molecular analysis of avian circadian clock genes.

Unlike mammals, avian circadian rhythms are regulated by a multiple oscillatory system consisting of the retina, the pineal and the suprachiasmatic nucleus in the hypothalamus. To understand avian circadian system, we have cloned Clock and Period homologs (qClock, qPer2 and qPer3) and characterized these genes in Japanese quail. Overall, qCLOCK, qPER2 and qPER3 showed approximately 79%, approximately 46% and approximately 33% amino acid identity to mCLOCK, mPER2, mPER3, respectively. Clock was mapped to quail chromosome 4 and chicken chromosome 4q1.6-q2.1. Per2 and Per3 genes were both localized to microchromosomes. qClock mRNA was expressed throughout the day, while qPer2 and qPer3 showed robust circadian oscillation in the eye and the pineal gland. All three genes were expressed in various tissues. In addition, qPer2 mRNA was induced by light, but neither qClock nor qPer3 was induced. These results can explain the molecular basis for circadian entrainment in Japanese quail and also provide new avenues for molecular understanding of avian circadian clock and photoperiodism.

Animals↗

Modulation of Starling forces and muscle fiber maturity permits adenovirus-mediated gene transfer to adult dystrophic (mdx) mice by the intravascular route.

Duchenne muscular dystrophy (DMD) and other inherited myopathies lead to progressive destruction of most skeletal muscles in the body, including those responsible for maintaining respiration. DMD is a fatal disorder caused by defects in the dystrophin gene. Recombinant adenovirus vectors (AdV) are considered a promising means for therapeutic delivery of a functional dystrophin gene to DMD muscles. If AdV-mediated dystrophin gene replacement in DMD is to be successful, development of a systemic delivery method for targeting the large number of diseased muscles will be required. In this study we investigated two major factors preventing efficient AdV-mediated gene transfer to skeletal muscles of adult animals after intravascular AdV administration: (1) an inability of AdV particles to breach the endothelial barrier and enter into contact with myofibers, and (2) a relatively nonpermissive myofiber population for AdV infection due at least in part to insufficient levels of the coxsackie/adenovirus attachment receptor (CAR). On the basis of established principles governing the transendothelial flux of macromolecules, we further hypothesized that an alteration in Starling forces (increased hydrostatic and decreased osmotic pressures) within the intravascular compartment would facilitate AdV transendothelial flux via convective transport. In addition, experimental muscle regeneration was employed to increase the prevalence of immature myofibers in which CAR expression is upregulated. Here we report that by employing the above-described strategy, high-level heterologous reporter gene expression was achievable in hindlimb muscles of normal rats as well as dystrophic (mdx) mice (genetic homolog of DMD) after a single intraarterial injection of AdV. Microsphere studies confirmed enhanced transport into muscle of fluorescent tracer particles in the size range of AdV, and there was a high concordance between CAR upregulation and myofiber transduction after intraarterial AdV delivery. Furthermore, in mdx mice examined 10 days after intraarterial AdV delivery, the aforementioned procedures had no adverse effects on the force-generating capacity of targeted muscles. These findings have implications for eventual AdV-mediated gene therapy of generalized skeletal muscle diseases such as DMD using a systemic intraarterial delivery approach.

Adenoviridae↗

Mapping quantitative trait loci for circadian behavioral rhythms in SMXA recombinant inbred strains.

SM/J and A/J inbred strain of mice have different characteristics in circadian behaviors such as free-running period (tau), phase relationship (psi) between light-dark cycles and activity rhythms, and amount of wheel-running activity. To determine the genes which affect these behaviors, a quantitative trait locus (QTL) analysis using SMXA recombinant inbred strains derived from SM/J and A/J mice was performed. Concerning tau, two regions on chromosomes (Chrs) 7 and 18 surpassed the genome-wide suggestive level. As for psi, one suggestive QTL was detected on Chr 7. The QTLs which affect daily activity counts under light-dark cycles and constant darkness were mapped to the same chromosomal regions on Chrs 1 and 17, respectively. The provisional QTLs detected in the present study might be useful for understanding the complex mechanism regulating circadian behaviors.

Animals↗

Inhibitory action of brotizolam on circadian and light-induced per1 and per2 expression in the hamster suprachiasmatic nucleus.

Triazolam reportedly causes phase advances in hamster wheel-running rhythm after injection during subjective daytime. However, it is unclear whether benzodiazepine affects the PER: gene expression accompanying a behavioural phase shift. Brotizolam (0.5 - 10 mg kg(-1)) induced large phase advances in hamster rhythm when injected during mid-subjective daytime (circadian time 6 or 9), but not at circadian time 0, 3 or 15. Brotizolam (5 mg kg(-1)) significantly reduced the expression of PER:1 and PER:2 in the suprachiasmatic nucleus 1 and 2 h after injection at circadian time 6, and slightly reduced them at circadian time 20. Injection of 8-OH-DPAT (5 mg kg(-1)) at subjective daytime induced similar phase advances with a reduction of PER:1 and PER:2 expression. Co-administration of brotizolam with 8-OH DPAT failed to potentiate the 8-OH DPAT-induced phase advances and reduced PER: expression. Both phase advance and rapid induction of PER:1 and PER:2 in the suprachiasmatic nucleus after light exposure (5 lux, 15 min) at circadian time 20 was strongly attenuated by co-treatment with brotizolam 5 mg kg(-1). The present results strongly suggest that reduction of PER:1 and/or PER:2 expression during subjective daytime by brotizolam may be an important step in causing a behavioural phase advance. The co-administration experiment suggests that common mechanism(s) are involved in brotizolam- or 8-OH DPAT-induced phase advances and the reduction of PER: gene expression. These results suggest that brotizolam is not only a good drug for insomnia but also a drug capable of facilitating re-entrainment like melatonin.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

Anterolateral thigh flap donor-site complications and morbidity.

The authors examined donor-site complications and morbidity in 37 patients after reconstruction with free or pedicled anterolateral thigh flaps. Intraoperative assessment included damage to the vastus lateralis muscle and whether the main pedicle of the rectus femoris muscle had been killed. Postoperative assessment of the donor site included wound healing, range of motion, muscle strength, gait, and sensation. Patients were surveyed with a questionnaire about fatigue in their activities of daily life and the appearance of the donor site. All 32 patients who underwent primary skin closure could perform activities of daily life normally, and most (87.5 percent) reported that donor-site appearance was satisfactory. However, the severity of donor-site dysfunction was related to the degree of damage to the vastus lateralis muscle, and most patients (87.5 percent) had some loss of sensation at the anterolateral aspect of the thigh. Because of adhesions between the meshed skin graft and the underlying fascia, range of motion at the hip and knee was limited in significantly more patients who had received split-thickness skin grafts (60 percent) than patients who had undergone primary skin closure (3.1 percent). Therefore, wider flaps or flaps harvested nearer the knee may increase donor-site morbidity. The authors concluded that the incidence of long-term morbidity with the anterolateral thigh flap is low, although it is increased when the flap includes the vastus lateralis muscle or is wider and requires additional skin grafting at the donor site.

Adult↗

Postoperative complications and functional results after total glossectomy with microvascular reconstruction.

Microsurgical reconstruction after total glossectomy can greatly improve quality of life; however, postoperative functional results are often unstable, and the effectiveness of total glossectomy remains questionable. To determine the problems of reconstruction after total glossectomy with laryngeal preservation and to examine the functional results of swallowing and speech, 30 patients who had undergone total glossectomy and reconstruction with free flaps were reviewed for this study. The patients ranged in age from 20 to 73 years, and 23 of the 30 had undergone reconstruction with a rectus abdominis musculocutaneous flap. Wider and thicker flaps were designed and transferred and were sutured to suspend the larynx. To maintain physiologic swallowing function after surgery, the extent of laryngeal suspension and cricopharyngeal myotomy was limited. Of the 30 patients, 21 (70 percent) could be decannulated with laryngeal preservation; 20 of these 21 could tolerate a normal/soft/pureed diet, and 1 was limited to a fluid diet. Speech was intelligible in 16 of the 19 patients evaluated. In 9 of the 30 patients, laryngeal function could not be preserved. In four of these nine patients, additional resection combined with total glossectomy caused severe aspiration and recurrent pneumonia. Two patients with preoperative cerebral dysfunction were also poor candidates for laryngeal preservation. Additionally, the transferred flap's lack of bulk in the oral cavity and the advanced age (73 years) of one patient and the poor motivation of another may have contributed to postoperative aspiration. Aspiration occurred in one patient because of local recurrence of a tumor. The presence of preoperative cerebral dysfunction (p = 0.025), resection of the epiglottis (p = 0.005), and postoperative orocutaneous fistulas (p = 0.04) were significantly associated with the failure of laryngeal preservation. However, because of the difficulty of enrolling a sufficient number of patients in the study and the inherent limitations of retrospective studies, multivariate analysis in this study showed that no factors, such as patient age, flap volume, and the type of neck dissection, were significant predictors of laryngeal preservation. Although prospective studies are necessary, the function of individual patients must be assessed so that the study experiences discussed here can be applied to subsequent patients.

Adult↗

Association of aldehyde dehydrogenase 2 gene polymorphism with multiple oesophageal dysplasia in head and neck cancer patients.

BACKGROUND: Multiple occurrences of oesophageal dysplasia are frequently observed in head and neck cancer patients, and closely associated with alcohol consumption. Acetaldehyde, the first metabolite of ethanol, is thought to play an important role in the carcinogenesis of the upper aerodigestive tract. AIM: To investigate if genetic polymorphism in alcohol metabolising enzymes (ADH3, alcohol dehydrogenase 3; ALDH2, aldehyde dehydrogenase 2) is associated with oesophageal multiple dysplasia in head and neck cancer patients. METHODS: Thirty one consecutive patients with head and neck cancer were included in the study. Multiple oesophageal dysplasia was detected endoscopically as multiple Lugol voiding lesions (multiple LVL) using the Lugol dye staining method. The ADH3 and ALDH2 genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: Among the 31 patients with head and neck cancer, 17 had multiple LVL. Multiple LVL were closely associated with a second primary oesophageal carcinoma in head and neck cancer patients (odds ratio 60.7, 95% CI 5.6-659). Furthermore, the mutant ALDH2 allele was significantly more prevalent in patients with multiple LVL (65% v 29%; p<0.05) whereas no difference was observed in ADH3 polymorphism. CONCLUSIONS: The mutant ALDH2 allele appears to be a risk indicator for multiple LVL in head and neck cancer patients. Accumulation of acetaldehyde due to low ALDH2 activity may play a critical role in cancerous changes throughout the mucosa in the upper aerodigestive tract.

Aged↗

Influenza A virus infection and pulmonary microthromboembolism.

This report presents the cases of two patients with rapidly progressive hypoxemia associated with influenza A(H3N2) virus infection, who were diagnosed with influenza related acute pulmonary microthromboembolism by serum D-dimer, lung perfusion and ventilation scans and computed-tomography scan of the chest, and were successfully treated by anti-coagulant therapy. The present cases suggest that acute onset pulmonary microthromboembolism should be considered in some patients with sudden, unexplained dyspnea during an outbreak of influenza infection and prompt diagnosis is essential to save the patient from acute death associated with influenza.

Aged↗

[Cancer therapy and processing information].

The National Cancer Center Japan started to provide free, computer-based cancer information, through a service called the National Cancer Center--Cancer Information Service (NCC-CIS), to patients and their families, physicians and other health professionals via fax (telephone) and the Internet in 1996. NCC-CIS in Japanese is modeled on the Physician Data Query service produced by the National Cancer Institute in the United States and is produced from an independent standpoint adopted to the medical and social environment in Japan. NCC-CIS provides up-to-date cancer treatment information (staging, prognosis and state-of-the-art treatment by stage of disease), supportive care for each type of cancer, an image reference database, and a directory of organizations and lecture meeting reports in Japan in order to facilitate better understanding of cancer among people and support the decision-making process for physicians in order to achieve a reduction in cancer deaths.

Humans↗

Potential role of microvessel density in predicting radiosensitivity of T1 and T2 stage laryngeal squamous cell carcinoma treated with radiotherapy.

Curative radiotherapy is the first choice of therapy for T1 and T2 stage laryngeal squamous cell carcinoma (LSCC) patients to preserve their phonation. Patients with recurrent tumors who undergo salvage surgery require prolonged nasal feeding. Therefore, clinical interest has been focused on elucidating a predictive factor indicating which tumors are likely to be radiosensitive before radiotherapy. We analyzed the relations between radiosensitivity and clinicopathological factors (gender, tumor location, histological factors, and clinical tumor-node-metastasis stage), expression of apoptosis-related proteins (p53, bax, bcl-2), apoptotic index using the terminal deoxynucleotidyltransferase-mediated nick end labeling method, expression of cell proliferation-related proteins (Ki-67-labeling index and epidermal growth factor receptor overexpression) and microvessel density (MVD, vessels/field = 0.391 mm2) in biopsy specimens from 31 LSCC patients given radiotherapy (total radiotherapy dose of 52-70 Gy over 4-6.5 weeks). Univariate analysis revealed that tumors with a high MVD (> or =35 vessels/field) showed better radiosensitivity than those with a low MVD (<35 vessels/field, P = 0.008) and that a high Ki-67-labeling index (> or =40%) was weakly associated with radiosensitivity (P = 0.056). Multivariate analysis and Kaplan-Meier analysis showed that MVD alone had significant predictive power for radiosensitivity in T1 and T2 stage LSCCs after radiotherapy (P = 0.012, 0.0003, respectively). No significant association between clinicopathological factors, or of overexpression of p53, bax, bcl-2, epidermal growth factor receptor, or apoptotic index, with radiosensitivity was found. These results indicate that MVD is a potentially useful clinical factor predicting radiosensitivity for patients with early stage LSCCs before treatment.

Aged↗

Adenovirus-mediated utrophin gene transfer mitigates the dystrophic phenotype of mdx mouse muscles.

Utrophin is a close homolog of dystrophin, the protein whose mutations cause Duchenne muscular dystrophy (DMD). Utrophin is present at low levels in normal and dystrophic muscle, whereas dystrophin is largely absent in DMD. In such cases, the replacement of dystrophin using a utrophin gene transfer strategy could be more advantageous because utrophin would not be a neoantigen. To establish if adenovirus (AV)-mediated utrophin gene transfer is a possible option for the treatment of DMD, an AV vector expressing a shortened version of utrophin (AdCMV-Utr) was constructed. The effect of utrophin overexpression was investigated following intramuscular injection of this AV into mdx mice, the mouse model of DMD. When the tibialis anterior (TA) muscles of 3- to 5-day-old animals were injected with 5 microl of AdCMV-Utr (7.0 x 10(11) virus/ml), an average of 32% of fibers were transduced and the transduction level remained stable for at least 60 days. The presence of utrophin restored the normal histochemical pattern of the dystrophin-associated protein complex at the cell surface and resulted in a reduction in the number of centrally nucleated fibers. The transduced fibers were largely impermeable to the tracer dye Evans blue, suggesting that utrophin protects the surface membrane from breakage. In vitro measurements of the force decline in response to high-stress eccentric contractions demonstrated that the muscles overexpressing utrophin were more resistant to mechanical stress-induced injury. Taken together, these data indicate that AV-mediated utrophin gene transfer can correct various aspects of the dystrophic phenotype. However, a progressive reduction in the number of transduced fibers was observed when the TA muscles of 30- to 45-day-old mice were injected with 25 microl of AdCMV-Utr. This reduction coincides with a humoral response to the AV and transgene, which consists of a hybrid mouse-human cDNA.

Adenoviridae↗

The relationship between ocular melatonin and dopamine rhythms in the pigeon: effects of melatonin inhibition on dopamine release.

Our previous study has shown that the phases of circadian rhythms of ocular melatonin and dopamine are always opposite and intraocular melatonin injection suppresses dopamine release. Therefore, it is possible that dopamine rhythms result from inhibitory action of melatonin. We have examined this possibility in the following experiments. In the first experiment effects of continuous light on melatonin and dopamine release were examined. The data indicated that continuous light exposure resulted in loss of circadian rhythmicity of melatonin and dopamine by suppressing melatonin and enhancing dopamine levels throughout the day. To further examine the effects of light in the second experiment, 2 h light pulse was applied during the night, then temporal changes of melatonin and dopamine release were studied. The light pulse rapidly suppressed melatonin release, whereas it rapidly increased dopamine release. These changes occurred within 30 min in both melatonin and dopamine. However, the recovery after the cessation of the light stimulus was slower in melatonin than dopamine. In the third experiment it was tested if dopamine release was increased by lowering melatonin release with an intraocular injection of the D2 agonist, quinpirol. Although quinpirol strongly inhibited melatonin release independently of the time of injection, dopamine did not always increase by the inhibition of melatonin. These results indicate that ocular dopamine rhythms are not simply produced by melatonin inhibitory action.

Animals↗

Functional diversities of two activity components of circadian rhythm in genetical splitting mice (CS strain).

CS mice, an inbred strain, showed two distinctive characteristics in the circadian rhythm of locomotor activity: (1) large variation in the freerunning period, and (2) spontaneous rhythm splitting under continuous darkness. In the splitting rhythm there was a positive correlation between the freerunning period of the evening component and the activity time of the morning component. The phase-shifting effect of a 15-min light pulse was examined on the two activity components of the splitting rhythm. There were significant differences in the amount of light-induced phase response between the two components. A light pulse during the late subjective night induced a phase advance shift only in the morning component, while a light pulse during the early subjective night induced a phase delay shift only in the evening component. These results indicate functional diversities of the two activity components in the circadian locomotor rhythm of CS mice, and suggest that the circadian system in CS mice consists of two mutually coupled oscillators which have different circadian periods and different responsiveness to light. The CS mouse is a useful model to explore a genetic background of oscillator coupling in the circadian system of nocturnal rodents.

Animals↗

Free adipofascial flap for scalp reconstruction: case report.

The authors describe a case in which a large defect of the scalp was present after tumor excision. It was covered with a free adipofascial flap and a split-thickness skin graft, with satisfactory results. Numerous similar cases of scalp defects reconstructed with other free flaps have been described. But since donor-site morbidity is minimized with free adipofascial flaps, they should be used more often for reconstruction of scalp defects.

Adipose Tissue↗