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Biomedical subjects

Y Ohtani

Publications and source records attributed to Y Ohtani.

At least 19 recordsLinked to original sources
PubMed2001

Leukemia inhibitory factor induces nociceptin mRNA in cultured rat cortical neurons.

The effects of leukemia inhibitory factor (LIF) on the expression of neurotransmitter synthetase and neuropeptide mRNAs in cultured rat cortical neurons were examined by reverse transcription-polymerase chain reaction. Nociceptin mRNA expression was increased by treatment with 20 or 80 ng/ml LIF for 24 h, but choline acetyl transferase, glutamic acid decarboxylase, enkephalin, dynorphin, substance P, somatostatin and galanin mRNA expression were not altered by LIF. These observations indicated a specific effect of LIF on nociceptin gene regulation in cultured cortical neurons.

Aging↗
PubMed2001

Efficient production of menaquinone (vitamin K2) by a menadione-resistant mutant of Bacillus subtilis.

Efficient production of menaquinone (MK) by Bacillus subtilis was achieved. An edible strain of B. subtilis, isolated from the traditional Japanese food natto, was mutated to improve MK productivity. A menadione-resistant mutant producing 30% more MK than its parent strain was obtained. Soybean extract and glycerol were the best nitrogen and carbon sources, respectively, among the sources tested. Addition of yeast extract also increased MK productivity. The maximum concentration of MK reached about 35.0 mg/l after 4 days of culture in a jar fermenter. The pH of the medium decreased to 5.5 after the start of cultivation, then spontaneously increased to 7.7-8.0. This pH change might be important in the production of MK because only small amounts of MK were obtained when pH was controlled at 5.7, 6.0, 7.0, 7.5 or 8.0.

Bacillus subtilis↗
PubMed2001

Pseudohyperkalaemia caused by recentrifugation of blood samples after storage in gel separator tubes.

Because hyperkalaemia above a certain level is life-threatening, erroneous interpretation of serum potassium concentration may misguide and complicate diagnostic procedures. We investigated a number of cases with pseudohyperkalaemia, which was assumed to have been caused by the recentrifugation of blood samples after storage in gel separator tubes. The time trend of serum potassium concentration was explored before (January-March 1997) and after (May-July 1997) ceasing the practice of recentrifuging blood samples after overnight storage. Next, we conducted an experiment on a volunteer's serum. The sample was divided into two groups and centrifuged once (control group) or twice (recentrifugation group). For both groups, serum potassium concentrations were measured immediately, and at 24, 48 and 72 h. For the recentrifugation group, the second centrifugation was done just before the measurement. The time series study showed that the mean serum potassium concentrations measured after overnight storage were 4.68 (95% CI: 4.60-4.76) mmol/L before and 4.14 (4.07-4.20) mmol/L after ceasing the practice of recentrifugation. The experiment showed that the mean serum potassium concentrations in the control group versus the recentrifugation group were 3.95 (95% CI: 3.89-4.01) mmol/L versus 4.05 (3.92-4.17) immediately (P=0.0979), 3.95 (3.89-4.01) versus 5.95 (5.61-6.29) at 24 h (P=0.0001), 4.13 (4.05-4.22) versus 6.90 (6.46-7.34) at 48 h (P=0.0001), and 4.22 (3.85-4.58) versus 7.61 (6.94-8.30) at 72 h (P<0.0001). Recentrifugation of blood samples after storage causes a spurious rise in serum potassium concentration to the degree of clinical significance. Clinicians and biochemists should take appropriate measures to stop this practice.

Artifacts↗
PubMed2001

Reconstruction of heavily calcified aorta and its visceral branches without extracorporeal circulation.

A 61-year-old Japanese female was referred to our hospital for surgical treatment of a localized heavily calcified abdominal aorta. Preoperative angiograms and computed tomograms revealed severe stenosis of the aorta, resembling a slit. Bypass grafting between the thoracic and abdominal aorta was successfully performed together with the reconstruction of the celiac artery, superior mesenteric artery, and bilateral renal arteries without extracorporeal circulation. Postoperative angiograms showed patency of the graft and branches. A localized heavily calcified abdominal aorta is relatively rare, and the cause of this entity might be Takayasu's aortitis.

Aged↗
PubMed2001

Postnatal development of lymphatic vessels and their smooth muscle cells in the rat diaphragm: a confocal microscopic study.

This paper reports on how lymphatic vessels and their smooth muscle cells develop in the diaphragm of postnatal rats. Lymphatic endothelial cells in the diaphragm were labeled by an intraperitoneal injection of DiI-labeled acetylated low-density lipoprotein (DiIac-LDL). During postnatal week 1, DiI-ac-LDL was detected in many free cells in addition to distinct endothelial cells that formed lymphatic vessels. Occasionally, saccular lymphatics isolated from previously formed lymphatics were recognized; these were referred to as lymphatic islands. The DiI-ac-LDL-labeled free and lymphatic endothelial cells showed immunoreactivity for CD 34 and Flt-4, but most of them did not express either OX 62 or ED 1 immunoreactivity, with only some showing ED 1 immunoreactivity. This suggests that most of the DiI-ac-LDL-labeled elements were lymphatic endothelial cells, and that some were macrophages. After postnatal week 1, the DiI-ac-LDL positive cells were restricted to lymphatic vessels. Until postnatal week 6, lymphatic vessels increased as the diaphragm enlarged. Towards the end of postnatal week 2, free cells expressing alpha-smooth muscle actin (alpha-SMA) immunoreactivity increased in the diaphragm, and some of these were in contact with lymphatics. A coarse plexus of smooth muscle cells surrounding the lymphatic vessels first appeared at postnatal week 2, and this plexus became denser with age. Our findings indicate that lymphatic vessels are formed not only by sprouting from previously formed lymphatic vessels but also by migrating endothelial cells, and that smooth muscle cells may be differentiated from mesenchymal cells to form a plexus surrounding the lymphatic vessels.

Animals↗
PubMed2001

[A case of Churg-Strauss syndrome in which positive rheumatoid factor and MPO-ANCA preceded the development of clinical symptoms of vasculitis].

A 52-year-old man in whom bronchial asthma had been diagnosed in 1995 was admitted for the treatment of Churg-Strauss syndrome in June 1997. Positive tests MPO-ANCA and rheumatoid factor preceded the symptoms of vasculitis for several months. A skin biopsy revealed infiltration of eosinophils in the vessel walls, and the diagnosis of Churg-Strauss syndrome was confirmed. After systemic administration of corticosteroids, the symptoms other than mononeuritis improved markedly, and his MPO-ANCA and rheumatoid factor became negative. Rheumatoid factor and MPO-ANCA may be useful for the early diagnosis of Churg-Strauss syndrome in patients with bronchial asthma in which a well-controlled disease develops into an intractable condition.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed2001

Phylogeny and ontogeny of the lymphatic stomata connecting the pleural and peritoneal cavities with the lymphatic system--a review.

This paper reviews the phylogeny and ontogeny of "lymphatic stomata" through which fluids and cells in the pleural and peritoneal cavities enter the lymphatic system. In amphibians, the pleuroperitoneal cavity is connected through numerous pores with the wide subvertebral lymphatic sinus corresponding to the thoracic duct in mammals. In reptiles, direct connections of the pleural and peritoneal cavities with the lymphatic system have been reported. In mammals, the pleural and peritoneal cavities are directly connected with lymphatics through lymphatic stomata. How do lymphatic stomata develop in mammals? In the rat, distinct lymphatics are noted in the subpleural space of the diaphragm periphery in 16 days old embryo. With age, the supleural lymphatics increase and form a polygonal network. They show a tubular appearance and possess many valves. Some of them become endowed with smooth muscle cells. In 19 days old embryos, some lymphatics appear in the subperitoneal space of the diaphragm. They extend centripetally and form many lateral projections that later elongate and connect with those from adjacent lymphatics, thus forming a lattice-like network or "lymphatic lacunae". During early postnatal days, the lymphatic lacunae project many bulges that subsequently come into contact with the pores among mesothelial cells lining the diaphragmatic peritoneum, thus forming lymphatic stomata. They increase until postnatal week 10. The lymphatic stomata in the costal pleura also develop during early postnatal days.

Aging↗
PubMed2000

Expression of inducible nitric oxide synthase mRNA and production of nitric oxide are induced by adenosine triphosphate in cultured rat microglia.

The effect of adenosine triphosphate (ATP) on the expression of the inducible nitric oxide synthase (iNOS) mRNA and production of nitric oxide in cultured rat microglia was examined. ATP induced iNOS mRNA dose-dependently (100-1,000 microM). The induction began within 1 h after addition of ATP (100 microM) with peak expression occurring at 6 h. The release of nitric oxide to culture medium was significantly increased by the treatment with ATP (100 and 1,000 microM) for 12 and 24 h. These results indicate that ATP is a potential mediator to induce iNOS mRNA expression and NO production in microglia.

Adenosine Triphosphate↗
PubMed2000

Enantioselective determination of bromoisovalerylurea by liquid chromatography on chiral stationary phase in reversed- or normal-phase partition mode.

Bromoisovalerylurea (bromvalerylurea) is a sedative-hypnotic given orally as a racemate. Enantiomers of this drug could be separated by high-performance liquid chromatography on the three chiral stationary phases (a vancomycin-bonded, beta-cyclodextrin derivative-bonded, or urea derivative-bonded phase). Biological fluids of human subjects who had ingested toxic or therapeutic doses of the racemate were chromatographed after liquid-liquid extraction. The (+)-enantiomer concentration was almost equal to the (-)-enantiomer concentration in the serum of one overdosed patient. In all the other subjects, the (+)-enantiomer was less than the (-)-enantiomer in their sera and saliva. The data suggest that the drug is absorbed non-stereoselectively from the gastrointestinal tract and eliminated from the blood stereoselectively.

Adult↗
PubMed2000

Neuroaxonal leukodystrophy associated with congenital cutis laxa: report of an autopsy case.

A male patient, who was born with congenital cutis laxa characterized by cutaneous laxity due to the degeneration of elastic fibers, presented with an arrest of mental and motor development at the age of 3 years. The progressive decline of the psychomotor abilities led to the patient's death at the age of 4 years and 9 months. An autopsy revealed extensive white matter degeneration, characterized by the formation of numerous neuroaxonal spheroids and a diffuse loss of axons and myelin sheaths. The centrum semiovale and the cerebellar white matter were the most severely affected. The ultrastructure of the spheroids was consistent with a dystrophic type of axonal swelling. Neurons of the cerebral cortex, cerebellar cortex, and some brain stem nuclei were lost in moderate to severe degrees, and there were relatively few neuroaxonal spheroids in the gray matter. The pallidum and substantia nigra were well preserved. Neuroaxonal leukodystrophy, in which the spheroid formation predominantly affects the white matter, is the rarest variant of primary neuroaxonal dystrophies, and there are very few reports of autopsied cases. Among the reported cases, two Japanese siblings had congenital skin lesions similar to those of our case. The unique association of neuroaxonal leukodystrophy and congenital cutis laxa may form a distinct variant in this disease category.

Brain↗
PubMed2000

Summation between nearby motion signals and facilitative/inhibitory interactions between distant motion signals.

To explain the finding that motion assimilation was dominant between nearby motion signals while motion contrast between distant ones, a center-surround antagonistic mechanism was proposed [Nawrot & Sekuler (1990). Vision Research, 30, 1439-1451]. However, motion assimilation occurred not only between nearby signals but also between distant ones, suggesting the existence of a center-surround non-antagonistic mechanism [Ido. Ohtani & Ejima (1997). Vision Research, 37, 1565-1574]. The present study was designed to provide direct evidence for the non-antagonistic mechanism, and to examine further the motion interactions which operate in different spatial scales. The nature of motion interaction between the test and the inducer was examined by varying the size, the number of frames, the frame duration and the inter-frame displacement of random-dot kinematograms. The results were consistent with the notion that there are three types of interactions in human motion processing; one is a summation process effective within nearby regions, and the other two are facilitative and inhibitory induction processes operating over larger spatial scales. Analysis of the results in terms of the Fourier components suggests that the facilitative and the inhibitory induction processes may be sensitive, respectively to the lower and the higher temporal frequency components of the stimulus.

Humans↗
PubMed2000

The test of variables of attention (TOVA) is useful in the diagnosis of Japanese male children with attention deficit hyperactivity disorder.

The purpose of this study was to evaluate the ability of the test of variables of attention (TOVA) to distinguish between 6- to 12-year-old Japanese male children with attention deficit hyperactivity disorder (ADHD group; n=17) meeting DSM-IV and ICD-10 criteria, and age-matched, normal Japanese male controls (control group; n=19). The TOVA is a computer-administered, visual continuous performance test that provides measures of attention. The ADHD group had significantly higher means than the control group in all variables: omission errors, commission errors, response time, response time variability, anticipatory responses, and multiple response. Control children exhibited age-related changes in two variables: response time and response-time variability, but no age-related changes were observed in any variables in the ADHD group. This preliminary study indicates that the TOVA makes a useful contribution to the diagnosis of Japanese male children with ADHD.

Age Factors↗
PubMed2000

Chronic fatigue syndrome in childhood.

Chronic fatigue occurring in previously healthy children and adolescents is one of the most vexing problems encountered by pediatric practitioners. We report three cases, 11, 12 and 13-year-old children, with chronic fatigue syndrome (CFS). They initially developed a low grade fever and generalized fatigue, followed by sleep disturbance and psychosomatic symptoms, and their performance ability deteriorated. They were diagnosed as having CFS on the basis of criteria. To investigate the brain function in CFS patients, we examined the regional cerebral blood flow by single-photon emission-computed tomography (SPECT) with 111 MBq [123I]-iodoamphetamine (123I-IMP) or xenon-computed tomography (Xe-CT), and brain metabolic levels by MR spectroscopy (MRS). Blood flow, expressed as the corticocerebellar ratio (CCR), in the left temporal and occipital lobes was markedly lower in cases 2 and 3 than that in healthy subjects reported by another investigator. In case 1, however, blood flow in the left basal ganglia and thalamus was markedly higher than in healthy subjects. The MR spectroscopy (MRS) study revealed remarkable elevation of the choline/creatine ratio in the patients with CFS. None of our patients exhibited evidence of focal structural abnormalities on MRI. These findings suggest that the various clinical symptoms in CFS patients may be closely related to an abnormal brain function.

Adolescent↗
PubMed2000

Inhalation provocation tests in chronic bird fancier's lung.

BACKGROUND: Patients with chronic bird fancier's lung (BFL) can be classified into two types. One group of patients develops chronic disease with fluctuating acute episodes, including low-grade fever, mild exertional dyspnea, and cough (fluctuating chronic BFL; formerly termed recurrent and relapsing chronic BFL). The other group of patients shows no history of acute episodes (insidious chronic BFL). The diagnosis of chronic BFL is difficult, since the onset of chronic BFL may be insidious, with few if any symptoms during the early stages of the disease process. STUDY OBJECTIVE: To attempt to diagnose the conditions of these patients more precisely, inhalation provocation tests were conducted using avian dropping extracts. DESIGN: Retrospective chart review. SETTING: The Tokyo Medical and Dental University Hospital in Japan. PATIENTS: Eleven patients with chronic BFL (6 with fluctuating chronic BFL and 5 with insidious chronic BFL) and 6 control subjects (4 asymptomatic bird owners and 2 idiopathic pulmonary fibrosis patients) were evaluated. MEASUREMENTS AND RESULTS: Inhalation provocation tests using avian dropping extracts were conducted. All BFL patients were evaluated as positive or probable by inhalation challenge, whereas control subjects were evaluated as negative. A peripheral leukocytosis, an increase of alveolar-arterial oxygen pressure difference, an increase of body temperature, and the development of respiratory symptoms including cough and dyspnea were more frequently observed in chronic BFL patients than in control subjects. All the BFL patients had an increase in neutrophils in BAL fluids following inhalation challenge. CONCLUSIONS: We validated the utility of inhalation challenge for the diagnosis of chronic BFL, including fluctuating and insidious BFL. We also demonstrated that neutrophilia in BAL fluids following inhalation challenge could be added to the diagnostic criteria for chronic BFL.

Acute Disease↗
PubMed2000

A corrosion casting/scanning electron microscope method that simultaneously demonstrates clear outlines of endothelial cells and three-dimensional vascular organization.

This paper describes a method that can definitively demonstrate endothelial cell boundaries on corrosion casts of arteries, veins, and capillaries. After perfusion with silver nitrate, a casting medium was injected into the entire vascular bed. The injected tissues were either exposed to light or immersed in the photographic developer to develop the silver halide, and corroded in a 5% NaOH solution at 60 degrees C overnight. Observations of the casts containing water in a low vacuum scanning electron microscope equipped with a cooling stage clearly showed endothelial cell boundaries on casts of every type of vessel as well as their three-dimensional architecture. The low vacuum scanning electron microscope images of wet casts were almost identical in quality to the back-scattered electron images of dried casts without any coating. Secondary electron images of the dried casts with metal coating clearly showed endothelial cell outlines and nuclear imprints. The secondary electron images at high magnification indicated that silver granules were precipitated in the grooves along endothelial cell boundaries on the casts. Since this method can demonstrate endothelial cell boundaries of every type of vessel in addition to their three-dimensional architecture, it will be a powerful tool for examining endothelial cell morphology and microvascular organization in pathological as well as normal tissues.

Animals↗
PubMed2000

Acute intermittent porphyria associated with transient elevation of transaminases during an acute attack.

A 44-year-old woman with acute intermittent porphyria (AIP) was admitted to Kudanzaka Hospital because of abdominal pain. A cholecystectomy was performed in another hospital without improvement. On admission, her transaminases were elevated to greater than 1,000 mU/ml. After an intravenous drip of mainly glucose, her transaminases returned to normal. Her acute attacks occurred during stress, and she died of respiratory failure after repetitive acute episodes. AIP should be included in a list of the differential diagnosis of gastrointestinal diseases, neurosis, and hysteria. This is the first case of AIP accompanied by transient marked elevation of transaminases during an acute attack.

Adult↗