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Biomedical subjects

S Ebihara

Publications and source records attributed to S Ebihara.

At least 73 records · Page 4Linked to original sources
PubMed1997

Immunocytochemical identification of pinopsin in pineal glands of chicken and pigeon.

Pinopsin is a blue-sensitive photoreceptive molecule possibly involved in photic entrainment of the circadian pacemaker in the chicken pineal gland. To characterize pinopsin as a circadian photoreceptor, antibodies were raised against the C-terminal portion of pinopsin. As expected from the divergence of the amino acid sequence of this region, the resultant antibody cross-reacted with neither chicken rhodopsin nor red-sensitive cone pigment (chicken red). In Western blot analysis, the antibody stained a single band of 42-kDa protein in a detergent-extract of chicken pineal membranes, suggesting that pinopsin (calculated molecular weight, 38187) might be glycosylated and/or palmitoylated. Immunocytochemical examination of pineal sections of the chicken and the pigeon with this antibody revealed strong positive images for most of the membrane structures in the lumen of the follicles. This antibody also stained string- and bulb-shaped structures of the chicken parafollicular cells, the morphology of which resembles those of retinal photoreceptor cells. In contrast to the predominant distribution of pinopsin, a monoclonal antibody specific for chicken red stained a smaller number of membrane structures in the lumen of chicken pineal follicles. These results strongly suggest that the chicken pineal gland contains at least two types of photoreceptive molecules, pinopsin (major) and chicken red (minor). We show that the former molecule is localized in parafollicular pinealocytes and in the outer segments of pinealocytes that make contact with the follicular lumen.

Amino Acid Sequence↗
PubMed1997

Circadian rhythms of cardiovascular functions are modulated by the baroreflex and the autonomic nervous system in the rat.

BACKGROUND: We assessed the hypothesis that the baroreflex and the autonomic nervous system are important in the control of the circadian rhythms of cardiovascular functions. METHODS AND RESULTS: We continuously measured blood pressure (BP), heart rate (HR), and locomotor activity in sinoaortic denervated (SAD), sympathectomized, and atropine-injected rats by use of a radiotelemetry system. The circadian rhythm of mean blood pressure (MBP) was selectively disrupted in SAD rats under 12-hour light-dark (LD12:12) cycles as a result of an increase in MBP during the light period and disappeared under constant darkness (DD). The locomotor activity and HR were not remarkably affected by SAD. The circadian rhythm of MBP was suppressed in sympathectomized rats by a decrease in the MBP during the dark period, and the abrupt changes in MBP when the lighting was altered were not seen under LD. Under DD, an MBP rhythm similar to that observed under LD was obtained. Sympathectomized rats also showed lower HR levels during the dark period than intact rats under LD cycles. In atropine-injected rats, the MBP and HR increased, especially during the light period, resulting in a reduction of light-dark differences in MBP and HR. The locomotor activity showed an apparent 24-hour variation in the sympathectomized and atropine-injected rats. CONCLUSIONS: The disruption of the baroreflex selectively eliminates the circadian rhythm of BP, and the circadian rhythms of BP and HR are modulated by the autonomic nervous system in rats. The circadian rhythms of BP and HR are regulated by different mechanisms involving the autonomic nervous system.

Animals↗
PubMed1997

Role of cyclic ADP-ribose in ATP-activated potassium currents in alveolar macrophages.

There is growing evidence that extracellular ATP causes a dramatic change in the membrane conductance of a variety of inflammatory cells. In the present study, using the nystatin perforated patch recording configuration, we found that ATP (0.3-30 microM) induced a transient outward current in a concentration-dependent manner and that the reversal potential of the ATP-induced outward current was close to the K+ equilibrium potential, indicating that the membrane behaves like a K+ electrode in the presence of ATP. The first application of ATP to alveolar macrophages perfused with Ca2+-free external solution could induce the outward current, but the response to ATP was diminished with successive applications. Intracellular perfusion with a Ca2+ chelator, 1,2-bis(2-aminophenoxy)ethane-N,N,N', N'-tetraacetic acid, also diminished the response. When cyclic ADP-ribose (cADPR) was applied to the macrophage cytoplasm, a transient outward current was elicited. Thereafter, the successive outward current was inhibited, suggesting the involvement of cADPR in the response. Intracellular perfusion with inositol 1,4, 5-trisphosphate also induced a transient outward current, but the successive current was not inhibited. The ATP-induced outward current was abolished when 8-amino-cADPR (as a blocker of cADPR, 10(-6)-10(-5) M) was introduced into the cytoplasm. Homogenates of alveolar macrophages showed both ADP-ribosyl cyclase and cADPR hydrolase activities, and CD38 (ADP-ribosyl cyclase/cADPR hydrolase) expression was confirmed by reverse transcriptase-polymerase chain reaction and Western blot analyses. These results indicate that ATP activates K+ currents by releasing Ca2+ from cADPR-sensitive internal Ca2+ stores.

Adenosine Diphosphate Ribose↗
PubMed1997

Versatility of the free anterolateral thigh flap for reconstruction of head and neck defects.

OBJECTIVE: The anterolateral thigh flap has many advantages in head and neck reconstruction. However, it has not yet come into widespread use because of the anatomic variations of its perforators. Herein, we describe a safe operative technique related to the patterns of the perforators and discuss its wide versatility. SETTING: A national cancer center hospital. PATIENTS: Thirty-eight anterolateral thigh flaps were transferred. Confirmation and dissection of the flap pedicle were simultaneously performed with tumor resection. The design and elevation of the flap were carried out immediately after the tumor resection was completed. RESULTS: From the study of the anatomic variations of the perforators, septocutaneous patterns were recognized in 10 cases (26.3%) and musculocutaneous patterns in 28 cases (73.7%). All flaps were easily and safely elevated with our techniques. Thirty-six flaps survived. Partial necrosis was noted owing to excessive thinning procedure in one patient and total necrosis was noted owing to venous thrombosis at the anastomosis part in another patient. CONCLUSIONS: We found that the anterolateral thigh flap has numerous advantages. It is possible to perform the flap elevation and the tumor resection simultaneously. The flap is generally thin and is suitable for reconstruction of intraoral defects. Combined flaps with neighboring tissues and other, distant flaps can be used. Furthermore, since our technique minimizes the problems of confirmation and dissection of the perforators, we conclude that this flap can be successfully used to repair a variety of large defects of the head and neck.

Adult↗
PubMed1997

Preservation of the larynx after resection of a carcinoma of the posterior wall of the hypopharynx: versatility of a free flap patch graft.

BACKGROUND: Preservation of the larynx after resection of a pharyngeal tumor remains a challenging problem for the head and neck surgeon. METHODS: Nine patients with T1 or T2 carcinoma of the posterior wall of the hypopharynx (UICC 1987), who were treated surgically between 1984 and 1994, were studied. All patients underwent surgical resection of the tumor with laryngeal preservation and immediate reconstruction with free flap transfer. A free forearm flap was transferred in four patients and a free jejunal patch graft, in five patients. RESULTS: There was one flap loss, due to venous thrombosis. Successful larynx preservation was achieved in the remaining eight patients (89%). Although there was one local control failure, three patients remained free of disease for more than 5 years. CONCLUSIONS: Laryngeal preservation surgery using a free flap patch graft has proven very beneficial in selected cases with a carcinoma of the posterior wall of the hypopharynx.

Aged↗
PubMed1997

Immunoelectron-microscopic investigation of the subcellular localization of pinopsin in the pineal organ of the chicken.

Pinopsin is a photoreceptive molecule cloned from the chicken pineal organ. An antibody highly specific for pinopsin was applied in light- and electron-microscopic immunocytochemical studies of the pineal organ of 1 to 2-month-old chickens. Intense immunoreactivity was found in the follicular lumen at the light-microscopic level. In addition, small immunoreactive spherical or fibrous structures were diffusely distributed at the parafollicular aspect of the pineal organ. To identify immunoreactive elements precisely, we used pre-embedding immunoelectron microscopy. These studies revealed immunoreactive outer segments of pinealocytes arranged closely side by side in the follicular lumina. The thin initial portion of the outer segment arose from a basal body located in the inner segment. Immunoreactive pear-shaped outer segments occupied small lumina. Follicular lumina displayed immunonegative arrays of whorl-like lamellar membranes. Occasionally, these immunonegative structures were surrounded by immunoreactive concentric lamellar complexes. In the parafollicular pineal parenchyma, long slender cilium-like structures or enlarged cilia and concentric lamellar arrays showed intense immunoreactivity. All immunoreactive structures observed in this study were considered to represent outer segments of pinealocytes of the chicken pineal organ.

Animals↗
PubMed1997

Thyroglossal duct carcinoma: a case report.

We describe a 47-year-old woman with a 13-year history of asymptomatic midline submental swelling. Cytologic examination of a fine-needle aspiration specimen from the solid mass revealed adenocarcinoma. The preoperative diagnosis was thyroglossal duct carcinoma. A Sistrunk procedure was performed and microscopic examination revealed papillary adenocarcinoma. The postoperative course was uneventful and there were no signs of local recurrence or metastasis at one year after surgery.

Carcinoma, Papillary, Follicular↗
PubMed1997

Chromosomal mapping of the gene encoding serotonin N-acetyltransferase to rat chromosome 10q32.3 and mouse chromosome 11E2.

Pineal melatonin is produced during the night. Its nocturnal increase regulates circadian rhythms and the photoperiodic reproductive response. Serotonin is acetylated to N-acetylserotonin by serotonin N-acetyltransferase (SNAT) and then methylated to form melatonin by hydroxyindole-O-methyltransferase (HIOMT). The rhythmicity of melatonin synthesis is regulated by the rhythmic activity of SNAT. Most laboratory mice do not have melatonin because of a genetic defect in the activity of SNAT and/or HIOMT. In a previous study using a recombinant inbred strain, we have found that the locus controlling pineal SNAT activity (Nat4) is located on mouse Chromosome 11. Recently, SNAT has been cloned in the rat. In the present study, the gene encoding SNAT was localized, using a rat cDNA fragment, on rat and mouse chromosomes by direct R-banding fluorescence in situ hybridization (FISH). In addition, using molecular linkage analysis with interspecific backcross mice, a gene encoding SNAT was mapped on a mouse chromosome. The gene encoding SNAT was localized to rat chromosome 10q32.3 and mouse Chromosome 11E2 by FISH. The molecular linkage analysis demonstrated that the gene encoding SNAT maps 1.5 cM distal to D11Mit11. The data suggest that Nat4 encodes SNAT. These chromosomal locations are in a region of conserved linkage homology between the two species.

Animals↗
PubMed1997

Lack of ventilatory threshold in patients with chronic obstructive pulmonary disease.

We investigated whether the ventilatory threshold (VET) could be detected in 25 patients with severe chronic obstructive pulmonary disease (COPD). Exercise on a treadmill was performed until symptom-limited maximum oxygen uptake (VO2SL) was obtained. VET was absent in 14 patients (56%, VET(-) group) and present in the others (44%, VET(+) group). Basal pulmonary functions and dyspnea index (VE,SL/MVV) were not different between the two groups. Endurance time and exercise tolerance (VO2SL/bw) were significantly less in VET(-) than in VET(+). In the former group, PaO2 and pH at maximal exercise decreased and PaCO2 increased significantly, but HCO3- did not change compared with the corresponding values before exercise. In the latter group, PaCO2 at maximal exercise increased significantly, and pH and HCO3- decreased significantly compared with the values before exercise, but PaO2 did not. The changes in PaO2 and PaCO2 were not different between the two groups, but changes in pH and HCO3- in VET(+) were greater than those in VET(-). These results suggest that the absence of VET in some COPD patients indicates a lower exercise capacity without producing metabolic acidosis. This may be caused by rapidly developing dyspnea.

Aged↗
PubMed1997

Improvement of exercise performance with short-term nasal continuous positive airway pressure in patients with obstructive sleep apnea.

We examined the effects of nasal continuous positive airway pressure (CPAP) on exercise performance in patients with obstructive sleep apnea (OSA). Six patients were treated with nasal CPAP on seven successive days and underwent overnight sleep studies and multiple sleep latency test (MSLT) at the beginning and after the last day of the treatment. The subjects also performed incremental exercise testing using a bicycle ergometer followed by 0-w, 25-w, 50-w,--(3 minutes each) until maximum level. Arterial oxygen pressure, arterial carbon dioxide pressure at rest while awake, apnea/ hypopnea index, longest apnea duration, the lowest percutaneous oxygen saturation measured by a pulse oximeter and the value of MSLT were significantly improved after nasal CPAP. Moreover, maximal oxygen consumption was significantly increased from 1841 ml/min +/- 350 to 2125 ml/min +/- 351 (p < 0.05); however, other cardiorespiratory parameters did not change significantly. The improvement of exercise performance by short-term nasal CPAP treatment in OSA patients may correlate with the improvement of sleepiness.

Adult↗
PubMed1996

Vitamin B12 affects non-photic entrainment of circadian locomotor activity rhythms in mice.

Administration of vitamin B12 (VB12) has been reported to normalize human sleep-wake rhythm disorders such as non-24-h sleep-wake syndrome (HNS), delayed sleep phase syndrome (DSPS) or insomnia. However, the mechanisms of the action of VB12 on the rhythm disorders are unknown. In the present study, therefore, effects of VB12 on circadian rhythms of locomotor activity were examined in mice. In the first experiment, CBA/J mice were maintained under continuous light condition (LL) or blinded, and after free-running rhythms became stable, the mice were intraperitoneally injected with either VB12 or saline at a fixed time every day. In all the mice with tau > 24 h, saline injections resulted in entrainment of circadian rhythms, whereas not all the mice with tau < 24 h entrained to the injection. In contrast to saline injections, VB12 injections did not always induce entrainment and about half of the mice with tau > 24 h free-ran during the injection. In the second experiment, the amount of phase advances of circadian rhythms induced by a single injection of saline at circadian time (CT) 11 under LL was compared between the mice with and without VB12 silastic tubes. The results showed that the amplitude of phase advances was smaller in the mice with VB12 than those without VB12. In the third experiment, daily injections of saline were given to the mice with VB12 silastic tubes maintained under LL. In this chronic treatment of VB12 as well, attenuating effects of VB12 on saline-induced entrainment were observed. These results suggest that VB12 affects the mechanisms implicated in non-photic entrainment of circadian rhythms in mice.

Animals↗
PubMed1996

Spectral sensitivity of photoreceptors mediating phase-shifts of circadian rhythms in retinally degenerate CBA/J (rd/rd) and normal CBA/N (+/+)mice.

Light-dark cycles are the most important time cue for the circadian system to entrain the endogenous circadian clock to the environmental 24 h cycle. Although photic entrainment of circadian rhythms is mediated by the eye in mammals, photoreceptors implicated in circadian photoreception remain unknown. In our previous study, retinally degenerate CBA/J (rd/rd) mice were found to have lower circadian photosensitivity for phase-shifting the locomotor activity rhythms than normal CBA/N(+/+) mice. In the present study, the spectral sensitivity for phase-shifting the rhythms was examined in order to characterize the photopigments involved in circadian photoreception of these mice. The spectral sensitivity of CBA/J-rd/rd mice clearly fitted to the Dartnall nomogram for a retinal(1)-based pigment with a maximum at 480 nm, while the best fitted nomogram had a maximum at 500 nm in CBA/N- +/+ mice. These results suggest that circadian photopigments involved in CBA/J-rd/rd and CBA/N- +/+ mice may be different.

Animals↗
PubMed1996

Surgical treatment of mandibular osteoradionecrosis: versatility of the scapular osteocutaneous flap.

Osteoradionecrosis of the mandible is a serious complication of radiotherapy for head and neck cancer and no single treatment has to date met with consistent success. A free scapular osteocutaneous flap was successfully transferred in nine patients with mandibular osteoradionecrosis who before this had not responded to conservative treatment. All but one of the patients had good bone union and there was no evidence of recurrence during a mean follow up period of four years and one month. This flap not only provides a well-vascularised segment of the bone but also multiple, large skin paddles, each with an abundant and reliable blood supply. In addition, well-vascularised fascia and overlying subcutaneous tissue can be used to fill dead spaces and cover the bony segment and fixation plates. This reduces postoperative infection and promotes primary wound healing. This flap has proved useful for reconstruction of mandibular osteoradionecrosis, particularly when there is a large soft tissue defect.

Adult↗
PubMed1996

Free colon transfer: a versatile method for reconstruction of pharyngoesophageal defects with a large pharyngostoma.

Free transverse colon transfers based on the middle colic vessels were used to reconstruct a pharyngoesophageal defect in 9 patients. In all patients, cancer invaded up to the oropharynx. Resection resulted in a larger pharyngostoma than normally seen following standard total pharyngolaryngoesophagectomy. In such cases, it can be difficult to achieve good swallowing function after reconstruction using the free jejunal transfer. This mainly results from a significant discrepancy between the diameter of the pharyngostoma and that of the jejunum. Compared to the jejunum, the transverse colon has a larger diameter with a longer vascular pedicle and can provide a longer, straight intestinal tube, facilitating easy passage of a food bolus. In our series, all transfers survived well and all patients had good swallowing function postoperatively. We consider that a free colon transfer is more suitable than a free jejunal transfer for pharyngoesophageal reconstruction in patients with a large pharyngostoma.

Aged↗
PubMed1996

[Relief of dyspnea after lung volume reduction in patients with pulmonary emphysema].

We studied dyspnea and pulmonary function during treadmill exercise in 10 patients with pulmonary emphysema before and at least 3 months after thoracoscopic volume reduction. Dyspnea was significantly less after surgery. Ventilatory function, gas exchange, respiratory muscle function, and exercise performance also improved significantly. The degree of volume reduction, estimated by the decrease in FRC as measured by body plethysmography correlated with the degree to which dyspnea was relieved. Volume reduction may be appropriate as a treatment for dyspnea in patients with pulmonary emphysema.

Dyspnea↗
PubMed1995

Measurement of circadian rhythms of ocular melatonin in the pigeon by in vivo microdialysis.

Ocular melatonin rhythms were measured in pigeons (Columba livia) by in vivo microdialysis. The birds were placed in light-dark cycles with 12 h of light and 12 h of darkness (LD12:12) or continuous dim light (LLdim) after LD12:12. Under LD12:12, melatonin levels were low during the light and high during the dark. The rhythms persisted under LLdim with lower levels during the subjective day and higher levels during the subjective night. Two hours of light exposure in the middle of the night acutely suppressed melatonin to the daytime level. These results indicate that microdialysis is useful for studies investigating the mechanism regulating ocular melatonin rhythms.

Animals↗
PubMed1995

Gramicidin-perforated patch recording: GABA response in mammalian neurones with intact intracellular chloride.

1. By the development of a new perforated patch method using gramicidin, the effects of GABA on neurones dissociated from the rat substantia nigra pars reticulata (SNR) were examined without disturbing the intracellular chloride concentration. 2. Using the patch pipette solution containing gramicidin (100 micrograms ml-1), the access resistance dropped to less than 20 M omega within 40 min after making the gigaohm seal. 3. Under current-clamp conditions, GABA caused a hyperpolarization accompanied by a blockade of spontaneous firing. Under voltage clamp at a holding potential (Vh) of -50 mV, GABA evoked an outward current by way of bicuculline- and picrotoxin-sensitive GABAA receptors. 4. A 10-fold change of extracellular chloride concentration resulted in a 58 mV shift of the reversal potential of GABA-induced outward current (EGABA), indicating that the membrane behaves like a chloride electrode in the presence of GABA. 5. The intracellular chloride activities (aCli), calculated with the Nernst equation using both extracellular chloride activity and EGABA values, ranged from 2.8 to 19.7 mM with a mean value of 9.5 mM. The aCli was not affected either by different pipette solutions or by different holding potentials more hyperpolarized than -40 mV. 6. In the recording from SNR neurones in brain slice using the gramicidin-perforated patch-clamp technique, the inhibitory and excitatory postsynaptic currents were recorded in different current directions and the former was blocked by bicuculline. 7. In conclusion, the gramicidin-perforated patch method will disclose previously unknown aspects of biological responses involving Cl-.

Amphotericin B↗