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Biomedical subjects

Y Nakao

Publications and source records attributed to Y Nakao.

At least 55 records · Page 3Linked to original sources
PubMed2000

BodyMap: a collection of 3' ESTs for analysis of human gene expression information.

BodyMap is a collection of site-directed 3' expressed sequence tags (ESTs) (gene signatures, GSs) that contains the transcript compositions of various human tissues and was the first systematic effort to acquire gene expression data. For the construction of BodyMap, cDNA libraries were made, preserving abundance information and histologic resolutions of tissue mRNAs. By sequencing 164,000 randomly selected clones, 88,587 GSs that represent chromosomally coded transcripts have been collected from 51 human organs and tissues. They were clustered into 18,722 independent 3' termini from transcripts, and more than 3000 of these were not found among ESTs assembled in UniGene (Build 75). Assessment of the prevalence of polyadenylation signals and comparison with GenBank cDNAs indicated that there was no significant contamination by internally primed cDNAs or genomic fragments but that there was a relatively high incidence (12%) of alternative polyadenylation sites. We evaluated the sensitivity and resolution of expression information in BodyMap by in silico Northern hybridization and selection of tissue-specific gene probes. BodyMap is a unique resource for estimation of the absolute abundance of transcripts and selection of gene probes for efficient hybridization-based gene expression profiling.

3' Untranslated Regions↗
PubMed2000

Experimental sensitization with Japanese cedar pollen in dogs.

Japanese cedar pollinosis is a type I allergic disease mediated by immunoglobulin E (IgE) antibodies to Japanese cedar (Cryptomeria japonica) pollen antigen (CPAg). By using 22 dogs consisting of 20 dogs aged 3 months and 2 dogs aged 3 years, immunization was performed by subcutaneous injections of CPAg with aluminum hydroxide gel. Variable levels of CPAg-specific IgE antibody response were detected in 21 of the 22 immunized dogs two weeks after the second immunization. This study provided an experimental sensitization system with CPAg in dogs, which will be useful for further immunological studies on Japanese cedar pollinosis.

Animals↗
PubMed2000

A new method to identify the internal auditory canal during the middle cranial fossa approach: a preliminary report.

A new method which facilitates identification of the internal auditory canal during the middle cranial fossa approach is described. This method uses illumination of the external auditory meatus as a guide to the internal auditory canal. When the external auditory meatus is illuminated by a light source system such that used for a flexible fiberscope, areas of the middle ear air cell system are illuminated and observable through the plate of bone constituting the base of the middle cranial fossa. In the case of ordinary pneumatization of the middle ear system, the attic is the site of the most intense illumination. Knowledge of the exact location of the attic obtained by this new method is extremely useful when performing drilling to expose the internal auditory canal in the middle cranial fossa approach. This is because the internal auditory canal is located medial to the attic, and also because such knowledge is helpful in identifying the two conventional landmarks of this approach, i.e., the arcuate eminence and the greater superficial petrosal nerve, as the locations of these structures are intimately related to the attic. The method described is very simple, timesaving and inexpensive, and is very helpful in detecting the internal auditory canal. Further anatomical study is being undertaken to establish a method of pinpointing the internal auditory canal, starting from the attic which is readily identifiable by use of this method.

Ear, Inner↗
PubMed2000

[Dental device (sleep splint)].

Sleep splint, which is a dental device made of regin, is now widely used for the treatment of obstructive sleep apnea in our country. This device is worn in the mouth at night and makes the upper airway opened during sleep. It enlarges the velopharyngeal space as well as the space at the tongue base and prevents the collapse of the upper airway. This device is a treatment of choice for the patients with mild or moderate types of obstructive sleep apnea who are not treated ordinarily by nasal CPAP. When the patients have nasal obstruction, adenoid hypertrophy, enlarged tonsils, or improper conditions of the teeth, sleep splint is not indicated for those patients. At first, nasal obstruction should be treated, and the adenoids and enlarged tonsils should be removed surgically. The compliance of this treatment is better than that of nasal CPAP, and the major complication of this treatment is almost none.

Humans↗
PubMed2000

[Response to immunoadsorption and steroid therapies in a patient with carcinomatous Lambert-Eaton myasthenia syndrome accompanied by disturbed consciousness].

A 75 year-old man developed gait disturbance and somnolence over a period of three months. Electroencephalography indicated theta slowing and cerebrospinal fluid (CSF) examination showed an increased cell count of 23/microliter and IgG of 7.2 mg/dl. He showed fatigue-inducing muscle weakness and the Harvey-Masland test demonstrated a low M-wave amplitude of 0.6 mV which increased to 3 mV with 50 Hz high-frequency stimulations. The serum titer of P/Q type anti-voltage-gated calcium channel (VGCC) antibody was quite high at 11,901 pmol/L (< 20 pmol/L). The patient was diagnosed as Lambert-Eaton myasthenia syndrome (LEMS) although at first no carcinoma was detected. Immunoadsorption therapy with a phenilalanine absorber column resulted in a reduction in the titer of anti-VGCC antibody to half of the initial concentration, but it increased again within several days. Six repeats of immunoadsorption and concomitant administration of prednisolone at a dose of 40 mg daily succeeded in reducing the anti-VGCC antibody titer of to below 390 pmol/L. The patient's consciousness disturbance and muscle weakness improved simultaneously over the next month and the lumbar puncture and electroencephalography showed normal results. Prednisolone administration was maintained at a dose of 30 mg daily and one year after occurrence of the first symptoms, a small cell lung carcinoma was detected. There was no evidence of limbic encephalitis such as an elevation of anti-Hu antibody in his CSF and serum or abnormal signal intensities in the hippocampal formations on MR imaging. The etiology of his disturbed consciousness remained unclear, but, in the case of LEMS, it could be a manifestation of a paraneoplastic syndrome associated with small-cell lung carcinoma. It is noteworthy that the anti-VGCC antibody titer rose to 1,262 pmol/L 2 months before his tumor was detected and decreased to 286 pmol/L after chemotherapy. P/Q type anti-VGCC antibody could therefore be a useful tumor marker reflecting activity of small-cell carcinoma.

Aged↗
PubMed1999

Regeneration across cold preserved peripheral nerve allografts.

The feasibility of peripheral nerve allograft pretreatment utilizing cold storage (5 degrees C in the University of Wisconsin Cold Storage Solution) or freeze-thawing to prevent rejection was investigated. Regeneration across cold-stored (3 or 5 weeks) or freeze-thawed (FT), 3.0-cm sciatic nerve allografts were compared to fresh auto- and allografts in an inbred rat model. At 16-week post-engraftment, only FT allografts appeared similar to autografts on gross inspection; FT grafts were neither shrunken nor adherent to the surrounding tissue as seen in the other allograft groups. Qualitatively, the pattern of regeneration in the graft segments of the fresh allograft and to a lesser extent of pretreated allografts was inferior to that of autografts as evidenced by a disruption in the perineurium, more extrafascicular axons, smaller and fewer myelinated axons, increased intrafascicular collagen deposition, and the persistence of perineurial cell compartmentation and perivascular infiltrates. Distal to these grafts, the regeneration became more homogenous between groups, although areas of ongoing Wallerian degeneration, new regeneration as well as compartmentation, were more prevalent in fresh and pretreated allografts. Although the number of myelinated fibres was equivalent to autografts, the fibre diameters, the number of large diameter fibres, and the G-ratio were significantly decreased in the allograft groups, which, in part, accounted for the significant decrease in conduction velocity in the 3-week stored and fresh allograft, and the slight decrease in the 5-week stored and FT allograft groups. There was a small return in the Sciatic Function Index towards normal, but no consistent differences between groups were found. Prolonged cold storage and freeze-thawing of nerve allografts resulted in regeneration that was better than fresh allografts, but inferior to autografts. With the concomitant use of host immunosuppression or other immunotherapies, these storage techniques can provide a means of transporting nerve allografts between medical centres and for converting urgent into elective procedures.

Action Potentials↗
PubMed1999

The surgical treatment of fixed subaortic stenosis: a clinical experience in Japan.

We report herein the results of a retrospective study conducted on ten consecutive Japanese patients who underwent successful surgical relief of fixed subaortic stenosis between 1972 and 1994 at ages ranging from 8 months to 21 years, and followed for 3.6 years and 26 years. Associated cardiovascular defects were present in six patients, two had a history of infective endocarditis, a discrete fibrous ring was found in nine patients, and a redundant abnormal sheet was found in one. A stenotic structure was removed in nine patients and incised in one, while myotomy was additionally performed in one. There were no early complications or deaths. Cardiac catheterization revealed a significant decrease in the peak systolic pressure gradient from 84+/-22 mm Hg preoperatively to 32+/-22 mm Hg postoperatively (P = 0.0017). Reoperation of an aortic valve replacement with or without valvular annulus enlargement was required in four patients because of a small annulus with aortic insufficiency or infective endocarditis. Infective endocarditis was a major cause of late mortality (n = 1) and morbidity (n = 1), but the remaining eight patients have been asymptomatic. Thus, although this lesion is relatively rare in Japan, the typical discrete type may be more common than previously believed. While a relief operation is associated with low early mortality, the palliative aspect regarding pathology of the aortic valve should not be underestimated, including poor growth of the valve annulus, deterioration of aortic insufficiency, and infective endocarditis. The most appropriate operative procedure for reoperation remains to be evolved.

Adolescent↗
PubMed1999

Expression and role of heat-shock protein 65 (HSP65) in macrophages during Trypanosoma cruzi infection: involvement of HSP65 in prevention of apoptosis of macrophages.

The 65-kDa heat-shock protein (HSP65) is thought to play a role in host defense against infections with various microbial pathogens and in autoimmune inflammatory disorders. We investigated the biological function and expression mechanism of HSP65 in macrophages of mice infected with Trypanosoma cruzi. BALB/c mice, which are susceptible to T. cruzi, showed high levels of parasitemia, and 80% of these mice died within 42 days after the infection, whereas resistant C57BL/6 or DBA/2 mice showed low levels of transient parasitemia and all survived. HSP65 expression was correlated with resistance to T. cruzi infection; HSP65 was more strongly expressed in macrophages of resistant C57BL/6 and DBA/2 mice than in macrophages of susceptible BALB/c mice. Immunodeficient BALB/c-nu/nu (nude) and C.B-17 scid/scid (SCID) mice were shown to be highly susceptible to this infection, and they did not express detectable levels of HSP65, suggesting that T cells play essential roles in the expression of HSP65 as well as in protective immunity against the infection. CD4(+) T cells, but not CD8(+) T cells or gammadelta T cells, were the cell population responsible for the induction of HSP65 expression in macrophages. Furthermore, depletion of asialo GM-1(+) NK cells made resistant C57BL/6 mice more susceptible to the infection, and HSP65 expression in their macrophages was abolished. Semiquantitative reverse transcription PCR analyses showed that both interferon gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) mRNA levels in CD4(+) T cells became low when resistant C57BL/6 mice were depleted of NK cells, suggesting that NK cells contribute to functional differentiation of CD4(+) T cells and thereby affect the induction of HSP65 expression. To determine the function of HSP65, macrophages were treated in vitro with antisense oligonucleotide for HSP65 prior to inducing HSP65 with IFN-gamma plus TNF-alpha or T. cruzi infection. This treatment did not affect the production of nitric oxide following activation, but the treated macrophages became susceptible to apoptosis. These results indicate that HSP65 plays a role in preventing the apoptosis of macrophages and thereby contributes to host resistance against T. cruzi infection.

Animals↗
PubMed1999

Cerebrovascular hemodynamics and ischemic tolerance: lipopolysaccharide-induced resistance to focal cerebral ischemia is not due to changes in severity of the initial ischemic insult, but is associated with preservation of microvascular perfusion.

Lipopolysaccharide (LPS), administered 72 hours before middle cerebral artery (MCA) occlusion, confers significant protection against ischemic injury. For example, in the present study, LPS (0.9 mg/kg intravenously) induced a 31% reduction in infarct volume (compared with saline control) assessed 24 hours after permanent MCA occlusion. To determine whether LPS induces true tolerance to ischemia, or merely attenuates initial ischemic severity by augmenting collateral blood flow, local CBF was measured autoradiographically 15 minutes after MCA occlusion. Local CBF did not differ significantly between LPS- and saline-pretreated rats (e.g., 34 +/- 10 and 29 +/- 15 mL x 100 g(-1) x min(-1) for saline and LPS pretreatment in a representative region of ischemic cortex), indicating that the neuroprotective action of LPS is not attributable to an immediate reduction in the degree of ischemia induced by MCA occlusion, and that LPS does indeed induce a state of ischemic tolerance. In contrast to the similarity of the initial ischemic insult between tolerant (LPS-pretreated) and nontolerant (saline-pretreated) rats, microvascular perfusion assessed either 4 hours or 24 hours after MCA occlusion was preserved at significantly higher levels in the LPS-pretreated rats than in controls. Furthermore, the regions of preserved perfusion in tolerant animals were associated with regions of tissue sparing. These results suggest that LPS-induced tolerance to focal ischemia is at least partly dependent on the active maintenance of microvascular patency and hence the prevention of secondary ischemic injury.

Animals↗
PubMed1999

[Four cases of abducens palsy caused by a vascular lesion of the vertebrobasilar system].

Several pathological conditions are responsible for abducens palsy, but a lesion of the vertebral artery (VA) has rarely been recognized as one of the causes. It has been reported that a high percentage of cases of abducens palsy are involved with ruptured dissecting aneurysms of the VA. We investigate the vertebrobasilar anatomy in 4 patients, suffering with abducens palsy. One patient revealed a fusiform dilatation of the vertebral artery on the same side as the abducens palsy. Three patients were noted to have stenosis of the vertebral artery from the origin of the posterior inferior cerebellar artery (PICA) to the union. Finally, four patients were found to have abnormal vertebrobasilar anatomy, which was on the same side as the abducens palsy. It is conceivable that changes of vertebrobasilar circulation may cause abducens palsy through direct compression, or ischemic events.

Abducens Nerve↗
PubMed1999

[Photostimulation that induces flattening of photopic electroretinograms--first report. An apparatus for slope photostimulation].

PURPOSE: We developed a new photostimulation system for electroretinograms (ERGs). This apparatus is capable of varying the transients during stimulus on and off (up-slope and down-slope times, respectively) as well as the stimulus and background intensities. We applied this system to evaluate the photopic ERG in human eyes. CASES AND METHODS: Seven normal volunteers and a 43-year-old patient with pre-proliferative diabetic retinopathy served as test subjects. We recorded ERGs with relatively long intervals of up-slope and down-slope times for photostimulation. RESULTS: As the up-slope and down-slope times were increased, the amplitude was reduced and the peak latency was prolonged for both the on and off responses. When the normal subjects' retinas were stimulated with a 341-msec up-slope time and a 34.1-msec down-slope time, the ERG waves showed complete flattening in both on and off responses. The ERGs of a patient with pre-proliferative diabetic retinopathy showed much longer peak latency than that of the normal volunteers as the up-slope time was prolonged. When the patient's retina was stimulated for a prolonged up-slope time, the average of the amplitude of ERG waves was similar to that of the normal volunteers. CONCLUSION: These results suggest that this new type of photostimulation might potentially uncover some novel aspect of clinical ERGs and might be useful for testing retinal functions of patients with diabetic retinopathy.

Adult↗
PubMed1999

[Influential factors in elevation of serum creatine phosphokinase for the patients with Kanemi Yusho].

We studied the etiology of the elevation of serum creatin phosphokinase (CK) using the data from routine medical checkup of Kanemi Yusho patients during 1995 and 1997. We also studied the serum CK and blood urea nitrogen (BUN) in rats given the polychlolinated biphenyls as well as controls, and conducted optical microscopic observation of muscle tissue in rats given the polychlolinated biphenyls and control. The patients with elevation of serum creatine phosphokinase also showed the elevation of BUN and polychlolinated biphenyls in their serum. These are thought to be triggers of the elevation of CK in the serum. However, animal experiments failed to yield the same results as human. The rats given polycholorinated biphenyls showed atrophy of muscle fibers. Accordingly, we were unable to clarify the etiology of CK elevation in humans and muscle atrophy in rats.

Animals↗
PubMed1999

Cerebral blood flow responses to somatosensory stimulation are unaffected by scopolamine in unanesthetized rat.

Studies with positron-emission tomography have indicated that muscarinic acetylcholine receptors may be involved in the mechanism of enhancement of cerebral blood flow (CBF) by neuronal functional activation. We examined the effects of muscarinic receptor blockade by scopolamine on the local CBF responses to vibrissal stimulation in the whisker-to-barrel cortex sensory pathway in unanesthetized rats. Local CBF was measured by the quantitative autoradiographic [(14)C]iodoantipyrine method. Scopolamine (0.4 or 0.8 mg/kg) was injected i.v. 30 min before measurement of local CBF; control rats received equivalent volumes of physiological saline. Vibrissae on the left side of the face were stroked continuously throughout the 1-min period of measurement of CBF. Local CBF was determined bilaterally in four structures of the pathway, i.e., spinal and principal sensory trigeminal nuclei, ventral posteromedial thalamic nucleus, and barrel field of the sensory cortex, as well as in four representative structures unrelated to the pathway. The higher dose of scopolamine raised baseline CBF in the two trigeminal nuclei, but neither dose diminished the percentage of increases in local CBF because of vibrissal stimulation in any of the stations of the pathway. These results do not support involvement of muscarinic receptors in the mechanism of enhancement of local CBF by functional neuronal activation, at least not in the whisker-barrel cortex sensory pathway in the unanesthetized rat.

Animals↗
PubMed1999

Electrocochleographic evaluation of hearing loss in acoustic neuromas.

OBJECTIVE: This study aimed to clarify the pathophysiology involved in the cause of hearing impairment due to acoustic neuromas (AN) with electrocochleograph (ECoG). STUDY DESIGN: The study design was a retrospective case study. SETTING: This study was conducted in a tertiary referral center. PATIENT: Thirty-four patients diagnosed as having AN by magnetic resonance imaging between 1988 and 1995. INTERVENTION: Diagnostic. MAIN OUTCOME MEASURES: The authors made a comparison between the patients' ECoG findings and the size of their tumors as determined by magnetic resonance imaging and a pure-tone audiometry (PTA). The disparity between the threshold of PTA and the detective threshold of compound action potential (CAP) or that of the cochlear microphonics (CM) was calculated. When the threshold of the PTA was worse than the detective threshold of the CAP or the CM, the disparity was regarded as indicating a hearing loss of retrocochlear origin. RESULTS: There was no correlation found between tumor size and the detective threshold of CAP or CM. Disparity was found to correlate with tumor size. CONCLUSIONS: These findings seem to indicate that retrocochlear damage in AN increases parallel to the growth of the tumor and that retrocochlear damage can be detected by the ECoG before surgery.

Adult↗
PubMed1999

[S-tube; a new device for the simulation of mechanical ventilation].

We introduce a new device which can be used to simulate the situation of mechanical ventilation. A Suzuki Snorkel-shaped Spirosimulation Tube (S-tube) consists of a truncated snorkel and an L-connector/slipjoint. The mouthpiece is placed in the subject's mouth and the rubber tip is held firmly between the teeth in order to form a secure connection between the mouth and the tube. The other end of the tube is connected to a ventilator. A nose clip is used to minimize the leakage of air from the subject's nostrils. The upper airway is thus connected to the S-tube with minimal leakage of air. The ventilatory pattern can be easily changed by altering the mode of the ventilator. Using this device, the subject can be placed under a variety of ventilatory patterns easily. Thus, this device can allow a trainee medical staff to better understand the different types of mechanical ventilation. This simple, non-invasive device is a useful educational tool for a medical staff.

Evaluation Studies as Topic↗