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Biomedical subjects

T Kitahara

Publications and source records attributed to T Kitahara.

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

Four cases of anti-myeloperoxidase antibody-related rapidly progressive glomerulonephritis during the course of idiopathic pulmonary fibrosis.

We report here 4 cases of rapidly progressive glomerulonephritis (RPGN) which developed during the management of idiopathic pulmonary fibrosis. In each patient, pulmonary disease preceded the onset of nephritis by 1 to 6 years. All patients had a high titer of serum autoantibodies against myeloperoxidase (MPO-ANCA) when the diagnosis of RPGN was made. Although the association of pulmonary fibrosis with ANCA-related glomerulonephritis has been occasionally described in the past literature, the sequence of pulmonary and renal injury has not been well defined. The present report demonstrates that idiopathic pulmonary fibrosis exists as a preceding condition in some patients with MPO-ANCA-related nephritis.

Aged↗
PubMed1999

Discordant expression of c-Ret and glial cell line-derived neurotrophic factor receptor alpha-1 mRNAs in response to motor nerve injury in neonate rats.

Adult motoneurons can survive following axotomy, whereas neonate motoneurons result in cell death. Following hypoglossal nerve axotomy in neonate rat, Glial cell line-Derived Neurotrophic Factor (GDNF) receptor alpha-1 (GFRalpha-1) mRNA expression was dramatically suppressed in the injured motoneurons, while a slight increase of c-Ret mRNA expression was observed. In adult, both GFRalpha-1 and c-Ret mRNAs increased substantially after axotomy. The present result suggests that the difference of motoneuron fate after axotomy may be partly due to the coordinate or discordant responses of GFRalpha-1 and c-Ret expression to nerve injury.

Aging↗
PubMed1999

Nitric oxide in the flocculus works the inhibitory neural circuits after unilateral labyrinthectomy.

We previously reported that nitric oxide (NO) production in the unipolar brush (UB) cells is involved in vestibular compensation [T. Kitahara, N. Takeda, P.C. Emson, T. Kubo, H. Kiyama, Changes in nitric oxide synthase-like immunoreactivities in unipolar brush cells in the rat cerebellar flocculus after unilateral labyrinthectomy, Brain Res. 765 (1997) 1-6]. To further elucidate the role of NO-mediated signaling in flocculus after unilateral labyrinthectomy (UL), we examined UL-induced Fos expression, a marker of neural activity, in vestibular brainstem with continuous floccular infusions of Nomega-nitro-l-arginine methyl ester (l-NAME), an inhibitor of NO synthase (NOS). After UL with floccular l-NAME infusions, Fos expression appeared in bilateral medial vestibular (MVe) and prepositus hypoglossal (PrH) nuclei. After UL with floccular saline infusions, however, Fos expression was observed only in the ipsi-MVe and contra-PrH. Furthermore, it has been revealed that UL with l-NAME infusions caused more severe vestibulo-ocular disturbances than UL with saline infusions at the initial stage [Kitahara et al. Brain Res. 765 (1997) 1-6]. Therefore, it is suggested that UL with floccular l-NAME infusions activates the contra-MVe and ipsi-PrH neurons and causes more severe imbalance between intervestibular nuclear activities at the initial stage. NO-mediated signaling in flocculus could be a possible driving force of the flocculus-mediated inhibition on the contra-MVe and ipsi-PrH at the initial stage of vestibular compensation.

Animals↗
PubMed1999

Opening of Rice Floret in Rapid Response to Methyl Jasmonate.

Effects of methyl jasmonate (MeJA) on rice floret opening were investigated in seven cultivars or hybrid combinations covering various variety types. Intact or excised panicles, judged to have florets just before anthesis, were soaked in 4 x 10(-5) - 4 x 10(-3)M MeJA solutions for 2 min at different temperatures. The results indicated that MeJA significantly induced opening of rice florets within about 30 min, with the most rapid induction occurring just 6 min after treatment. Numbers of induced opening florets are correlated with MeJA concentrations. Higher concentrations of MeJA induced more florets. pH values had no influence on MeJA effect, but MeJA required less time and induced more florets at 34 degrees C than at 25 degrees C. As far as we know, this is the first evidence that floret opening is induced by plant hormones. CO(2) evolution from panicles was also increased by MeJA treatment. Field experiments revealed that perfect flowering synchrony between the cytoplasmic male sterile (CMS) and restorer lines in hybrid seed production could be obtained by spraying MeJA solution on CMS line plants at the rate of 25 mg/m(2). As a result, many more hybrid seeds were harvested.

Journal Article↗
PubMed1999

The factors influencing haematoma volume due to arteriovenous malformations.

Haemorrhage due to cerebral arteriovenous malformations (AVMs) varies from massive, requiring urgent operations, to clinically silent. The present study was designated to identify factors influencing haematoma size, and the pathophysiological mechanisms of massive haemorrhage were studied. 55 patients with intracerebral haematomas due to supratentorial AVMs were included in this study. Angiographic and clinical findings were retrospectively evaluated in relation to haematoma size. Statistical analysis demonstrated that small size and the presence of only one draining vein were high risk factors for massive haemorrhage. The haematoma volume in small AVMs (30 +/- 4 cm3) was significantly larger than in other AVMs (7 +/- 3 cm3) (p = 0.0005). AVMs with only one draining vein were associated with massive haematoma volume as compared to AVMs with two or more draining veins (30 +/- 4 versus 11 +/- 3 cm3, p = 0.0023). Our previous study demonstrated that feeding artery pressure (FAP) was significantly higher in AVMs with haemorrhage than in those without, as was draining vein pressure (DVP), and FAP and DVP were inversely related to the number of draining veins and the size of the AVMs. Thus, in small AVMs and AVMs with only one draining vein, local increase in DVP may thus contribute to massive haemorrhage.

Arteriovenous Malformations↗
PubMed1999

A case of cimetidine-induced acute tubulointerstitial nephritis associated with antineutrophil cytoplasmic antibody.

We present a case of acute tubulointerstitial nephritis (ATIN) that developed in a 63-year-old man who had been taking cimetidine for treatment of a gastric ulcer. The constellation of clinical, laboratory, and histopathologic findings suggested drug-induced ATIN. Of interest, the patient had antineutrophil cytoplasmic antibody (ANCA) in his sera, reactive with myeloperoxidase, elastase, and lactoferrin. Prominent renal histological features included marked plasmacyte infiltration into the renal interstitium. Withdrawal of cimetidine resulted in complete resolution of renal findings, and the titers of ANCA concomitantly declined. Thus, cimetidine may have played a causative role in the development of ANCA-associated ATIN.

Anti-Ulcer Agents↗
PubMed1999

All-trans retinoic acid promotes the repair of tortuosity of elastic fibres in rat skin.

To elucidate the repair effects of all-trans retinoic acid (t-RA) on ultraviolet (UV)-induced tortuosity of elastic fibres in rat skin, the hind limbs of Sprague-Dawley rats were irradiated at a suberythemal dose of UV (three times/week for 6 weeks) and 0.025% t-RA in ethanol was applied topically five times/week for 6 weeks. The three-dimensional arrangement of elastic fibres with special reference to their linearity was quantified by image analysis using a scanning electron microscope following a combination of intravascular resin injection and selective digestion using formic acid. When t-RA was topically applied for 6 weeks on wrinkles formed by 6 weeks' exposure of the skin of rat hind limbs to UV radiation, the wrinkles disappeared to control levels, concomitant with an improvement in skin elasticity. The linearity of the elastic fibres was significantly (P < 0.01) increased compared with age-matched UV-irradiated controls. These findings suggest that the degeneration and deposition of elastic fibres accompanied by an increase in their linearity is involved in the process of wrinkle repair by topical application of t-RA.

Administration, Topical↗
PubMed1999

Association of head trauma with cervical spine injury, spinal cord injury, or both.

BACKGROUND: Links between cervical spine and/or spinal cord injuries and head trauma have not been reported in detail. METHODS: 188 patients with cervical spine and/or spinal cord injury were divided into two groups, i.e., with upper cervical and mid-lower cervical injury, and compared for head injury. RESULTS: Associated head trauma was investigated in 188 patients with cervical spine and/or spinal cord injuries; 35% had moderate or severe injuries. Brain damage was more frequently observed in patients with upper cervical injury than in those with mid to lower cervical injury. Those patients with upper cervical injury appeared to have an elevated risk of suffering skull base fractures, traumatic subarachnoid hemorrhage, and contusional hemotoma. CONCLUSIONS: Approximately one third of patients with cervical spine and/or spinal cord injuries had moderate or severe head injuries. Brain damage was more frequently associated with upper cervical injury. Those patients with upper cervical injury are at greater risk of suffering from skull base fractures and severe intracranial hematomas than those with mid to lower cervical injury.

Adolescent↗
PubMed1999

A phase II study of concomitant chemoradiotherapy for laryngeal carcinoma using carboplatin.

PURPOSE: We conducted a phase II study of concomitant chemoradiotherapy with carboplatin for laryngeal carcinoma. MATERIALS AND METHODS: Sixty-four patients with stage II-IV (stage II, 36; III, 19; IV 9) laryngeal carcinoma were treated with concomitant administration of carboplatin (CBDCA) during radiotherapy (CRT group) between 1991 and 1994. There were 36 supraglottic, 25 glottic, and 3 subglottic carcinomas. Patients with stage II and stage III-IV received intravenous CBDCA of 100 mg/m2 and 120 mg/m2 once a week, respectively. Tumor response was assessed at 40 Gy in 16 fractions to select the patients suitable for total laryngectomy or radical radiotherapy of 65 Gy in 26 fractions in 6.5 weeks. The treatment results were compared with the historical control consisting of 56 patients consecutively treated from 1988 to 1990 without chemotherapy (RT group). The two studies were comparable with regard to patient characteristics, including age distribution, gender, tumor location, size, and clinical stage. RESULTS: The actuarial 5-year survival rate was 80.3% for the CRT group and 81.3% for the RT group. A favorable response (complete response or partial response) at 40 Gy was observed in 87.5% of the patients of the CRT group and in 62.5% of the patients of the RT group (chi2 = 7.566, p < 0.01). The actuarial 5-year larynx preservation rate for the CRT group (75%) was significantly higher than that for the RT group (57%) in patients with T2 supraglottic carcinoma (p < 0.05). There was no difference in the larynx preservation rate between the two treatment arms for any T stage of glottic carcinomas. CONCLUSION: CRT using carboplatin improved the tumor response at 40 Gy and consequently achieved a higher larynx preservation rate for T2 supraglottic carcinoma. A clinical randomized trial is indicated to certify the findings of this phase II study.

Antineoplastic Agents↗
PubMed1999

Central motor reorganization in cerebral palsy patients with bilateral cerebral lesions.

Transcranial magnetic stimulation (TMS) has been used to describe cortical plasticity after unilateral cerebral lesions. The objective of this study was to find out whether cortical plasticity occurs after bilateral cerebral lesions. We investigated central motor reorganization for the arm and leg muscles in cerebral palsy (CP) patients with bilateral cerebral lesions using TMS. Seventeen patients (12 with spastic diplegia, 1 with spastic hemiplegia, and 4 with athetoid CP) and 10 normal subjects, were studied. On CT/MRI, bilateral periventricular leukomalacia was observed in all spastic patients with preterm birth. In two normal subjects, motor responses were induced in the ipsilateral tibialis anterior, but no responses were induced in any normal subject in the ipsilateral abductor pollicis brevis (APB) or biceps brachii (BB). Ipsilateral responses were more common among CP patients, especially in TMS of the less damaged hemisphere in patients with marked asymmetries in brain damage: in 3 abductor pollicis brevis, in 6 BBs, and in 15 tibialis anteriors. The cortical mapping of the sites of highest excitability demonstrated that the abductor pollicis brevis and BB sites in CP patients were nearly identical to those of the normal subjects. In patients with spastic CP born prematurely, a significant lateral shift was found for the excitability sites for the tibialis anterior. No similar lateral shift was observed in the other CP patients. These findings suggest that ipsilateral motor pathways are reinforced in both spastic and athetoid CP patients, and that a lateral shift of the motor cortical area for the leg muscle may occur in spastic CP patients with preterm birth.

Adolescent↗
PubMed1999

[Effect of the long distance truck driving in Hokkaido on cardiovascular system].

We took the blood pressure and ECG of 8 male truck drivers who drive long distances in Hokkaido and observed the conditions under which they work. Most of their driving routes included steep passes, and the weather and the road conditions became worse in winter. Their tasks were not only the driving and waiting but also such manual labor as loading, etc. The mean driving distance of one route was 705 km and it ranged from 159 km to 1,210 km. The mean number of working hours was 27.8 h, and it ranged from 9.2 h to 46.9 h. Blood pressure was higher when driving or loading than when resting or on a day off. The mean systolic blood pressure was over 140 mmHg in 6 cases, and arrhythmia occurred frequently in 4 cases during driving or loading. In 2 cases, in which the driver met with accident, the blood pressure was remarkably high and arrhythmia occurred frequently. Most drivers worked for a very long time in poor conditions and environment. The results of our study suggested that such a heavy work load will affect the cardiovascular system.

Accidents, Traffic↗
PubMed1999

[Labyrinthine fistulas in cholesteatoma].

The purpose of the present study was to investigate the clinical features of cases of cholesteatoma with labyrinthine fistulas, and in particular the pre and post-operative bone-conduction (BC). Cholestatoma patients with bone erosion or a defect found in the first stage operation were analyzed. The operations were conducted between 1992 and 1996. The patients were classified into four types, I, IIa, IIb, and III, according to Dornhoffer and Milewski's classification, which is based on different stages in the bone defect. A type I fistula is an erosion of the bony labyrinth with an intact endosteum. Type IIa is accompanied by an opened perilymphatic space with undisturbed perilymph while type IIb has a disturbed perilymph. A Type III fistula is an opened perilymphatic space with a disturbance of the underlying membranous labyrinth. Only 24 patients with type II and type III fistulas were included in this study. The location of the fistulas was the semicircular canals (SCCs) or/and the vestibula in 21 patients and in the cochlea in 3 patients. We examined the fistula by high-resolution computed tomography scan (CT scan) with 1 mm slice and 1 mm width axial-sections in 14 patients. A bone defect in the labyrinth was detected in 10 cases (71.5%) pre-operatively. Pre-operative BC was worse in the patients with cochlear fistulas than in those with fistulas located in SCCs or the vestibula. Within this latter group there were 13 type IIa (group IIa), patients and 8 type IIb or III (group IIb or III) patients. However, there was no difference in the pre-operative BC between these two sub-groups Tympanoplasty was conducted in all 24 patients. The postoperative BC of group IIa and group IIb or III were compared. Two of the 13 patients in group II a (15.4%) and 3 of 8 in group IIb or III (37.5%) had a deteriorated postoperative BC. Statistical analysis revealed that the postoperative BC was more inclined to become worse in patients with advanced stage IIb or III fistulas.

Adolescent↗
PubMed1998

Unilateral labyrinthectomy downregulates glutamate receptor delta-2 expression in the rat vestibulocerebellum.

The differential display method was applied to identify genes expression of which is altered in the flocculus after unilateral labyrinthectomy (UL). Total RNA from sham operated and labyrinthectomized rat flocculi was isolated, amplified by PCR using an arbitrary primer set and separated by electrophoresis on a polyacrylamide gel. PCR products the amounts of which were significantly lower in samples from labyrinthectomized animals than those from controls, were cut out of the gel and sequenced. One of the cDNA fragments showed 100% nucleotide sequence identity to the rat glutamate receptor (GluR) delta-2 subunit mRNA. In situ hybridization autoradiography showed that GluR delta-2 mRNA expression was intensely located to the floccular Purkinje cell layers. Furthermore, northern blot analysis showed that the delta-2 mRNA expression was decreased for at least two days after UL in accordance with diminishing UL-induced behavioral deficits. Therefore, it is suggested that the downregulation of delta-2 mRNA is involved in vestibular compensation. UL-induced spontaneous nystagmus (SN) was then examined in GluR delta-2 mutant mice. The frequency of SN in mutant mice was significantly more than that in wild mice until 12 h after UL. GluR delta-2-associated synaptic efficacy may be changed for the induction of vestibular compensation at the initial stage.

Animals↗
PubMed1998

Pharmacokinetics of serum glycerol and changes of ICP: comparison of gastric and duodenal administration.

To investigate the more effective route of oral administration of glycerol to decrease the raised ICP, two different routes were employed in the clinical practice. The one was through a Naso-Gastric tube, and the other was through an Entero-Duodenal tube. Pharmacokinetics of glycerol in relation to the decrease of ICP, and the changes of other parameters which could influence the serum osmotic pressure were sequentially monitored for initial 30 minutes. In the group of Entero-Duodenal route, the time to reach to the maximum glycerol concentration (Tmax) was faster, the maximum concentration of glycerol (Cmas) was higher, and ICP reduction rate was greater than these in the group of Naso-Gastric route. Other parameters (Na, K, BUN and Glucose) showed no significant difference between the two routes. It can be concluded that the Entero-Duodenal administration of glycerol is the more effective route to decrease the raised ICP, when it is administered orally.

Brain Injuries↗
PubMed1998

High-dose-rate intracavitary irradiation using linear source arrangement for stage II and III squamous cell carcinoma of the uterine cervix.

PURPOSE: The purpose of this article is to evaluate fractionated high-dose-rate (HDR) intracavitary irradiation using linear source arrangement (LSA) for patients with squamous cell carcinoma of the uterine cervix. MATERIALS AND METHODS: The subjects consisted of 217 patients (71 patients with stage II and 146 with stage III disease) who received external beam therapy (EBT) followed by fractionated HDR intracavitary irradiation using LSA between January 1980 and June 1990. In EBT, 40 Gy in 20 fractions (40 Gy/20 Fr) or 39.6 Gy/22 Fr was delivered to the whole pelvis and an additional 10 Gy/5 Fr or 10.8 Gy/6 Fr was delivered to the parametrium. The intracavitary irradiation dose was 30 Gy/6 Fr or 35 Gy/7 Fr with a daily fraction size of 5 Gy and two fractions per week. During the intracavitary treatment, most patients were treated on an out-patient basis. RESULTS: Cause-specific 5-year survival rates were 77% for stage II and 50% for stage III. Pelvic failure rates were 13% for stage II and 36% for stage III. In multivariate analyses, improved cause-specific survival was significantly associated with stage II (P = 0.0003), higher pretreatment serum hemoglobin level (P = 0.0015), higher pretreatment serum total protein level (P = 0.0029), and shorter total treatment time (P = 0.0024). The rate of severe (grade 3 or 4) late complication was 2% for the rectum, 1% for the small intestine or sigmoid colon and 1% for the bladder. CONCLUSIONS: Fractionated HDR intracavitary irradiation using LSA is an effective treatment for patients with uterine cervical cancer without need for hospitalization.

Adult↗
PubMed1998

A new mold material for customized patient positioning in radiotherapy.

MATERIALS: The new material consists of polystyrene beads coated in a polymerizing substance that when dampened, hardens within 10 min. RESULTS AND CONCLUSIONS: It has a density of less than a tenth of that of water and so is light-weight, a CT number of less than -800 and a minimal effect on the build-up of megavoltage photon beams.

Casts, Surgical↗