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Biomedical subjects

N Yoshimura

Publications and source records attributed to N Yoshimura.

At least 433 records · Page 24Linked to original sources
PubMed1992

Growth factor-dependent phosphorylation of membrane proteins in cultured human retinal pigment epithelial cells.

Recently, growth factors are known to phosphorylate tyrosine residues of proteins to regulate cellular functions. We investigated growth factor-dependent phosphorylation of membrane proteins in cultured human retinal pigment epithelial (RPE) cells. The phosphorylation experiments were done in membrane preparations of cultured RPE cell and the reaction was started by applying [32P]adenosine 5'-triphosphate (ATP) at 0 degrees C, and terminated after 0, 1, 5, 15, and 30 min. The samples were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and were analyzed by autoradiography. Many proteins showed time-dependent phosphorylation. Among them, a 170 kDa protein showed platelet-derived growth factor (PDGF)-specific phosphorylation with both time- (up to 30 min) and dose-(maximal effect at 50 ng/ml) dependence. On the other hand, epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) showed no specific phosphorylation. Phosphoaminoacids of the 170 kDa protein were analyzed by thin layer chromatography and autoradiography. Phosphotyrosine showed much higher radioactivity than phosphoserine or phosphothreonine. Consequently, PDGF induced phosphorylation of the 170 kDa protein which mainly consisted of phosphotyrosine. The data suggest that tyrosine phosphorylation of membrane protein is involved in signal transduction of PDGF in human RPE cells.

Adenosine Triphosphate↗
PubMed1992

[Serum 7S collagen levels in diffuse interstitial lung diseases--an index of the destruction of alveolar structure].

To examine whether alteration of 7S collagen in the alveolar basement membrane is related to the condition and prognosis of diffuse interstitial lung diseases (idiopathic interstitial pneumonia: IIP, collagen vascular diseases, sarcoidosis, and hypersensitivity pneumonitis), we measured serum 7S collagen levels in 123 patients with diffuse interstitial lung disease and other lung diseases. Patients with diffuse lung diseases (diffuse interstitial lung disease, pulmonary emphysema, and diffuse panbronchiolitis: DPB) showed significantly higher serum levels of 7S collagen than healthy normal controls. Serum 7S collagen levels in IIP and collagen vascular diseases were significantly higher than those in pulmonary emphysema and DPB. In cases of IIP, serum 7S collagen levels in the active stage were significantly higher than those in the inactive stage. Furthermore, the prognosis of patients with higher serum 7S collagen levels was significantly poorer than those of patients with lower serum 7S collagen levels. In infectious pulmonary diseases, serum 7S collagen levels of patients with adult respiratory distress syndrome (ARDS) were significantly higher than those of patients without ARDS. Autopsy specimens obtained from patients with positive serum 7S collagen showed diffuse alveolar damage and/or diffuse pulmonary hemorrhage in the alveolar areas. Immunohistochemical staining for 7S collagen showed disruption and/or loss of the alveolar basement membrane. The authors conclude that serum level of 7S collagen is useful for estimating the activity of diffuse interstitial lung diseases as an index of the destruction of alveolar structure.

Basement Membrane↗
PubMed1992

[Acute relapsing sensory neuropathy following upper respiratory infections--a case report].

A 44-year-old man developed numbness in his hands and feet and an unsteady gait following an upper respiratory symptoms. The symptoms progressed rapidly and reached maximum in a few days, followed by a gradual improvement over a few weeks, but his gait remained unsteady. His symptoms progressively increased over 14 years, with 11 relapses of similar episodes. Neurologic examination showed normal limb strength. Deep tendon reflexes were absent. Touch, cold, and pinprick sensation were impaired in his hands and feet. There was a profound loss of position and vibration sense in all extremities. He demonstrated an unsteady and broad-based gait. Electrophysiologic and histologic examination on the peripheral nerves revealed evidences of axonal degeneration without demyelination involving the sensory nerves.

Acute Disease↗
PubMed1992

Ca2+ mobilization in nontransformed ciliary nonpigmented epithelial cells.

To investigate the calcium second messenger system in nonpigmented epithelial (NPE) cells, we studied drug-dependent cytosolic free Ca2+ concentration ([Ca2+]i) transients in cultured nontransformed human and rabbit NPE cells with a fluorescent Ca2+ indicator, fura-2, and a digital video-imaging system. The main findings of this study were: (1) The basal [Ca2+]i was 141.9 +/- 1.2 nM (mean +/- standard error of the mean, n = 401) in humans and 157.0 +/- 1.4 nM (mean +/- SEM, n = 346) in rabbits. (2) Isoproterenol (10(-4) M) had little effect on [Ca2+]i mobilization in both species. Norepinephrine (10(-4) M) and epinephrine (10(-4) M) increased [Ca2+]i in 56% and 78% of rabbit NPE cells by 1.8- and 2.1-fold of basal [Ca2+]i, respectively, but induced little [Ca2+]i change in human NPE cells. Carbachol (10(-3) M) elicited significant [Ca2+]i increase (more than 3-4-fold of basal level) in about 60-70% of NPE cells in both species. Heterogeneity was seen in the cellular response to these agonists. (3) Norepinephrine-induced response was blocked by phentolamine (10(-5) M), and the effect of carbachol was blocked by atropine (10(-4) M). (4) Time course of norepinephrine-induced [Ca2+]i change was primarily monophasic. In contrast, [Ca2+]i transients induced by carbachol were mostly biphasic. (5) The duration of carbachol- or norepinephrine-induced responses were shortened by the chelation of extracellular Ca2+ without affecting other parameters of the reaction. This study confirms the presence of the calcium signaling system in cultured nontransformed human and rabbit NPE cells.

Adrenergic alpha-Antagonists↗
PubMed1992

[An autopsy case of neuronal type Charcot-Marie-Tooth disease (HMSN type II) with nerve deafness and psychiatric symptoms].

The clinical and pathological findings of a 41-year-old male patient with atypical Charcot-Marie-Tooth disease were reported. There were 3 cases of subarachnoid haemorrhage, 2 nerve deafness and 2 hereditary motor and sensory neuropathy (HMSN) in his family. He had suffered from progressive nerve deafness since 5 years old and gait disturbance since 37 years old. He had been admitted to the psychiatric hospital 3 times because of hallucinatory-delusional state and behavior abnormalities. Neurological examinations at 39 years old revealed that he had mental deterioration (IQ 66), nerve deafness, diffuse muscle atrophy, most marked distally, sensory disturbance, areflexia, positive Romberg's sign, orthostatic hypotension, dysphagia and slurred speech. MCV of median nerve was 27.8 m/sec, and SCV was not evoked. EEG revealed nonspecific dysfunction of the brain. He died of ileus-like condition at 41 years old. General autopsy showed haemorrhagic infarction of the jejunum and ileum due to compression of the superior mesenteric artery and vein by an adhesion band of connective tissue formed after previous appendectomy. Neuropathological examinations revealed axonal degeneration and loss of myelinated fibers with schwannosis of anterior and posterior spinal nerve roots as well as peripheral nerves. The posterior roots were more severely affected than the anterior ones. Ganglion cells of the posterior root ganglia showed remarkable degeneration and loss. There was severe degeneration of the posterior columns, especially in the gracilis, of the spinal cord. Nerve cells in the anterior horns and Clarke's columns also displayed conspicuous atrophy or central chromatolysis followed by gliosis. There was slight degeneration of the posterior spinocerebellar tracts.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Biodegradable microspheres containing adriamycin in the treatment of proliferative vitreoretinopathy.

The use of biodegradable polymer microspheres containing adriamycin for the treatment of proliferative vitreoretinopathy (PVR) in an experimental rabbit model was investigated. A single injection of microspheres containing 10 micrograms of adriamycin effectively decreased traction retinal detachment to 10% (n = 10), whereas 50% of eyes injected with blank microspheres (n = 10) developed retinal detachment (P < 0.05). A single injection of microspheres, containing 3 micrograms of adriamycin, did not suppress retinal detachment. Electroretinographic and histologic studies confirmed that the 10 micrograms injection of adriamycin in microspheres was not toxic to the retina, although the injection of the same amount of free adriamycin caused retinal necrosis and detachment. Thus, microspheres containing adriamycin hold promise as a new treatment modality for PVR.

Animals↗
PubMed1992

[Long-term results of the Blalock-Taussig shunts].

One-hundred and thirty-six patients received the classical Blalock-Taussig shunts between 1980 and 1990. Their age range at operation was 4 days to 12.8 years and their median age was 13 months. The operative mortality rate was 0.7% (1/136). The survivors were followed up from 1 month to 11.5 years, 5.4 years in average. Twenty-five patients required another shunt and the mean interval to that procedure was 2.4 years (modified Blalock-Taussig 23, classical Blalock-Taussig 2, Glenn 1, internal mammary artery-pulmonary artery shunt 1). Forty-five patients received corrective operations, there were four operative deaths (Fontan 2, Rastelli 2). There were 15 late deaths of which three deaths were not cardiogenic. One year after operation, 91.0% of patients remained in well-palliated condition. At three years after operation, 76.4% of patients continued to be in well-palliated condition. There were twelve neonates in this series. Their age range was 4 to 26 days and their median age was 13 days. There was no operative death. Five patients required second shunt. There were two late deaths. At present, six patients continue to be in well-palliated condition 8 months to 9 years after first operation. Angiographic findings showed the stenotic change of the vascular anastomoses in 49.3% (35/71) of patients. This study suggests that polydioxanone suture (PDS) will be useful for the growth of the anastomoses in Blalock-Taussig operation.

Anastomosis, Surgical↗
PubMed1992

[An experience with augmentation sigmoid cystoplasty for urinary incontinence caused by sacral agenesis: a case report].

Sacral agenesis is an uncommon disease. About 50 cases have been reported in Japan since 1929. Neurogenic bladder is often accompanied with the disease. The patient was a 26-year-old man who had suffered from persistent urinary incontinence since his childhood. Kidney-ureter-bladder (KUB) revealed Type IV sacral agenesis according to the classification by Renshaw. The upper urinary tract remained normal. Urodynamics study showed a low compliance bladder with low urethral pressure. Pharmacotherapy failed to improve his continence. Augmentation sigmoid-cystoplasty was undertaken to enlarge vesical capacity and it has successfully overcome his urinary incontinence. Clinical aspects of sacral agenesis are discussed focusing on urological problems.

Adult↗
PubMed1992

[Accessory tricuspid valve--a report of two cases].

Accessory tricuspid valve is a rare cardiac anomaly. We describe two cases with accessory tricuspid valve. Case 1: A 7-year-old boy underwent repair of tetralogy of Fallot. Under deep hypothermic cardiopulmonary bypass, right ventricle was opened. An accessory tricuspid leaflet was noted to the right side of the VSD attaching to the infundibular septum from medial papillary muscle as a chordal origin. After excision of the accessory tricuspid leaflet, the VSD was closed with a Dacron patch followed by relieve of the right ventricular outflow obstruction and pulmonary valvotomy. Case 2: A 8-year-old boy had Rastelli operation to correct transposition of the great arteries. An accessory leaflet originated from the medial papillary muscle and was floating like a parachute in the way between VSD and aorta. There was no additional apparatus in the pathway between the VSD and aorta after excision of the accessory tricuspid leaflet. Intraventricular tunnel was created with a Dacron patch. Extracardiac conduit between the right ventricle and the distal pulmonary artery was constructed using a valved pericardial roll.

Child↗
PubMed1992

Hypercaloric glycerol in injured patients.

BACKGROUND: This study investigates the effects of glycerol as a fuel source in the hypermetabolic patient (after injury). METHODS: Twenty-two patients were studied after multiple trauma and randomly assigned to either glucose or glycerol as the carbohydrate source (220 gm glycerol or 320 gm dextrose) during a lipid-based system of parenteral nutrition. In the immediate postoperative period, measurements were made of nitrogen balance, substrates, energy expenditure, insulin, glucagon, and liver function tests. RESULTS: In the glycerol group glucose concentrations in plasma were significantly lower, whereas glycerol levels increased nearly twentyfold. Insulin and glucagon levels increased in both groups; however, the rise in insulin level was greater in the glucose group, whereas glucagon increased in both groups to a similar degree. Nitrogen balance was restored to equilibrium in the glycerol group while remaining negative in the glucose group. No abnormalities in liver function test results or differences in serum albumin levels were noted in either group. A 12% thermic effect was noted in the glucose group but not in the glycerol group. CONCLUSIONS: Glycerol seems to be a viable fuel source in the traumatized patient, being associated with nitrogen retention and minimal thermal effect. A marked rise in plasma levels of glycerol does occur, but this does not appear to have any associated toxicity.

Adolescent↗
PubMed1992

[Neurogenic bladder caused by toluene abuse].

A 23-year-old man consulted the urological department of our hospital with a complaint of urinary retention. He had consulted the department of ophthalmology for decreased vision and visual defect in both of his eyes of 1 year duration. Urodynamic study revealed detrussor hyporeflexia. Neurologically cerebellar signs were seen. Auditory brain stem response and visual evoked potential revealed damage of the pons. Magnetic resonance imaging revealed atrophy of the cerebrum and cerebellum, dilatation of the fourth ventricle and loss of gray/white differentiation of the brain stem on T2-weighted sequence. Urinary level of hippuric acid was markedly high and the neurogenic bladder was considered to have been induced by the demyelinization at the pons which was caused by chronic toluene abuse.

Adult↗
PubMed1992

Neuropeptide-induced [Ca2+]i transients in cultured bovine trabecular cells.

Various kinds of neuropeptides have been identified to be immunoreactive in the drainage angle of mammalian eyes. However, little is known about second messenger system involvement with these peptides. To determine whether some of these peptides are linked to a calcium signalling system in the trabecular meshwork (TM) cells, their effects on [Ca2+]i transients in fura-2 loaded cultured bovine TM cells were studied with a digital video-imaging system. The main findings of this study were: (1) The basal [Ca2+]i was 164.0 +/- 1.0 nM (mean +/- standard error of the mean, n = 668). (2) Of the neuropeptides examined, neuropeptide Y (NPY) (10(-6)M) is the most potent because it increased [Ca2+]i by about four-fold from the basal level. Other peptides--substance P, bombesin, calcitonin gene-related peptide, and vasoactive intestinal peptide induced smaller increases in [Ca2+]i. (3) We defined a response as positive if [Ca2+]i increased to a value that was 1.2-fold over the basal level. The majority of the TM cells reacted to NPY, whereas only 20-30% of the cells reacted to any of the other peptides. (4) The chelation of extracellular Ca2+ shortened the half-life of a NPY-induced response without affecting its latency. (5) NPY (10(-6)M) significantly increased the formation of inositol triphosphate following a 15 sec exposure. The same was the case for inositol monophosphate and inositol diphosphate. The results of this study suggest that in bovine TM cells, NPY stimulation is coupled to Ca2+ signalling through an increase in polyphosphoinositide turnover.

Animals↗
PubMed1992

[Effects of endotracheal intubation on the trachea--usefulness of the evaluation by MRI].

Using an MRI apparatus, we observed the effects of endotracheal intubation on the trachea by measuring T1 value before and after an operation in ten surgical cases. T1 value of the anterior wall at the level of the first tracheal ring was 275.8 +/- 58 msec, and that of the posterior wall was 346.8 +/- 72 msec. The patients were all intubated under general anesthesia. Anesthesia was maintained with inhalation anesthesia such as nitrous oxide-oxygen-enflurane with the aid of vecuronium bromide. Periods of intubation varied between 80 to 46 minutes, and averaged 270 +/- 112 minutes. After the extubation, T1 value showed 312 +/- 62 msec at the anterior wall and 395 +/- 82 msec at the posterior wall. In the case of the posterior wall, T1 value was significantly prolonged compared with that of the pre-intubation period. Prolongation of T1 value is assumed to be related to the increase of tissue free water demonstrating the occurrence of tissue edema. From the findings that T1 value might be prolonged by endotracheal intubation, we conclude that the MRI apparatus is useful for investigating the effects of the intubation procedure on the trachea.

Adult↗
PubMed1992

[A case of benign intracranial hypertension with bilateral reversible thalamic lesions on magnetic resonance imaging].

A 10-year-old girl had complained of headache, vomiting and blurred vision for one month before admission to our hospital. Her neurological findings were normal, except that the examination of the fundi revealed papilledema. The cerebrospinal fluid pressure was elevated to 220 mmH2O. The brain MRI showed bilateral and approximately symmetrical hyperintense areas located in the thalamus. These disappeared on the repeated MRI, and her symptoms regressed spontaneously within a month. Her illness was diagnosed as benign intracranial hypertension because of the favorable clinical course. These reversible thalamic lesions might be due to circulatory insufficiency associated with intracranial hypertension.

Child↗
PubMed1992

Hyperthermia reduces the occurrence of proliferative vitreoretinopathy in a rabbit model.

The effects of hyperthermia on experimental proliferative vitreoretinopathy (PVR) in rabbits were studied. Heat treatment (42.4 degrees C for 30 min) of the retinal surface (as estimated from temperature measurement of the retrobulbar space) 2 to 3 hr after fibroblast injection reduced the occurrence of traction retinal detachment compared with control rabbits (P less than 0.02), but the incidence of pucker formation plus traction detachment was not significantly different between the two groups. In a separate experiment, heat treatment applied to normal rabbit eyes showed only reversible elongation in the latency of the electroretinographic b-wave without affecting the amplitude. Histologic examination revealed no significant changes in the heat-treated normal rabbit retina. Hyperthermia may be used as a new therapeutic tool for PVR.

Animals↗
PubMed1991

The effect of X-ray irradiation on human retinal pigment epithelial cell proliferation.

To obtain a rationale for the use of radiation in the treatment of proliferative vitreoretinopathy (PVR) and to determine the appropriate dose of irradiation, we studied the in vitro growth of cultured human retinal pigment epithelial (RPE) cells after various doses of irradiation. At 48 h after plating, doses of 100-3000 cGy were given to the cells by Linac X-ray. On days 1, 3, and 7 after irradiation, cell growth was evaluated by cell number and DNA synthesis. At 7 days after irradiation, the cell number declined to 42% and 3.7% of control values after doses of 300 and 1000 cGy, respectively. Almost the same inhibitory effects were observed following doses of 1000 cGy and 3000 cGy. DNA synthesis was suppressed to 67.6% and 2.8% of control values on the 7th day after radiation doses of 500 and 1000 cGy, respectively. Low-dose irradiation can be used as adjunctive therapy for PVR, and doses of 500-1000 cGy are most likely needed.

Cell Count↗