Biomedical subjects

R Tanaka

Publications and source records attributed to R Tanaka.

At least 487 records · Page 27Linked to original sources

PubMed1992

[Angiogenesis induced by rat glioma cells in vitro].

Angiogenesis induced by rat glioma cells was examined in vitro using a double chamber co-culture system. Cultured microvascular endothelial cells from Fisher 344 rat brain, rat C6 glioma cells and rat T9 gliosarcoma cells were used for this study. Endothelial cells, cultured on type I collagen, formed capillary-like structures. In the co-culture system, C6 glioma cells promoted this formation. On the other hand T9 gliosarcoma cells had no effect on it. The supernatants of C6 glioma cells and T9 gliosarcoma cells suppressed the proliferation of the endothelial cells. C6 glioma cells probably produce and release soluble factors promoting angiogenesis. The proliferation of endothelial cells is thus suppressed while angiogenesis is made more intense. This in-vitro model is useful to elucidate the mechanism of tumor angiogenesis and to evaluate the promoting and inhibiting factors of angiogenesis.

Angiogenesis Inducing Agents↗

PubMed1992

Effects of chronic tachycardia-induced cardiomyopathy on the beta-adrenergic receptor system.

Chronic supraventricular (or ventricular) tachycardia causes a dilated cardiomyopathy. Effective treatment requires ablation of the tachycardia using antiarrhythmic agents, cryoablation, electroablation, or surgical interruption/excision. However, the underlying pathophysiologic mechanisms responsible for the development of supraventricular tachycardia-induced cardiomyopathy have not been fully identified. We hypothesized that chronic supraventricular tachycardia is associated with significant changes in the beta-adrenergic system that may have implications for the pathophysiology and treatment of supraventricular tachycardia-induced cardiomyopathy. Accordingly, we examined the relationship between left ventricular function, plasma norepinephrine level, beta-receptor number and affinity, and response to a beta-agonist (isoproterenol) infusion in eight control pigs and eight pigs subjected to supraventricular pacing-induced tachycardia (240 beats/min for 3 weeks). Left ventricular function was measured using simultaneous echocardiography and catheterization. Left ventricular end-diastolic dimension and pressure increased in pigs with supraventricular tachycardia (5.1 +/- 0.4 cm and 27 +/- 2 mm Hg) versus control pigs (3.8 +/- 0.3 cm and 8 +/- 2 mm Hg), p < 0.05. Left ventricular fractional shortening decreased in supraventricular tachycardia (10 +/- 1%) versus control pigs (34 +/- 1%), p < 0.05. In addition, in the pigs with supraventricular tachycardia the fractional shortening versus left ventricular end-systolic stress relationship fell below the control relationship. Plasma norepinephrine level (measured by high-performance liquid chromatography) increased in pigs with supraventricular tachycardia (3592 +/- 1606 pg/ml plasma) versus control pigs (323 +/- 74 pg/ml plasma), p < 0.05. beta-Receptor number and affinity (measured by [3H]dihydroalprenolol binding) did not change in supraventricular tachycardia (98.6 +/- 11.5 fmol/mg protein and 7.2 +/- 1.1 nmol) versus control pigs (99.1 +/- 9.4 fmol/mg protein and 6.8 +/- 0.5 nmol). The response to isoproterenol infusion (10 micrograms/kg) in supraventricular tachycardia was blunted: the absolute increase in left ventricular peak (+)dP/dt was reduced in supraventricular tachycardia (833 +/- 233 mm Hg/sec) versus control pigs (2180 +/- 139 mm Hg/sec), p < 0.05. Chronic supraventricular tachycardia caused a decreased contractile state, increased plasma norepinephrine level, and caused no change in beta-receptor number or affinity; however, the response to beta-agonist infusion was blunted. These results suggest that chronic supraventricular tachycardia is associated with uncoupling of the beta-receptor from subsequent intracellular components of the beta-adrenergic system. Therefore medical management of chronic supraventricular tachycardia-induced cardiomyopathy before and immediately after definitive ablation may require use of pharmacologic agents whose actions do not depend on an intact beta-adrenergic pathway.

Animals↗

PubMed1992

[Studies on the teratogenic potential of p-tert-butylphenolformaldehyde resin in rats].

p-tert-Butylphenolformaldehyde resin, an adhesive, was given orally to pregnant Wistar rats by stomach intubation at the dose levels of 250, 500 and 1000 mg/kg body weight during days 7 to 17 of gestation, and the effects of the compound on dams and fetal developments were examined. No changes in general conditions, maternal body weight, food consumption, numbers of corpora lutea and implantation ratio were observed. There was no evidence of an increase in fetal death or of malformation attributable to the treatment with p-tert-butylphenolformaldehyde resin in any of dose levels examined. It was concluded that p-tert-butylphenolformaldehyde resin has no teratogenic effect in rats.

Administration, Oral↗

PubMed1992

Clinical application of spinal root neurograms for detection of conduction block in radiculopathy.

In order to assess effects on conductivity of the spinal nerve roots which were compressed due to lumbar disc herniation (LDH) and spinal canal stenosis (SCS) at the lumbosacral vertebrae, spinal nerve root potentials (SRP) were recorded epidurally at multiple levels upon stimulation of the tibial and peronea nerves. Subjects were five normal volunteers and fifteen clinical cases (10 LDH and 5 SCS). Simultaneous recording of evoked EMGs was used to identify afferent and efferent components of SRPs. The shortest latency SRP consisted of orthodromic group I afferent and antidromic alpha-efferent potentials. The potential on liminal M-wave stimulation was regarded as representing exclusively group I volley and that on maximal M-wave stimulation as predominantly alpha-efferents. A centrifugally conducting nerve potential for H-reflex could be also recorded. Conduction blockage in the lumbar spinal roots of the clinical cases could be recognized as increased positivity and desynchronization. Quantitative assessment of these signs was devised in comparison to the control data. The present method revealed at least one of these signs in all clinical cases, and was found useful to determine the levels at which surgical decompression is indicated, supplementing radiological examination.

Adolescent↗

PubMed1992

[A resected case of teratoma of the lung].

Teratoma of the lung in a 32-year-old female is reported. Abnormal shadow on chest X-ray film was noted at the age of 15 years. Her symptoms were subclinical fever, couch, hemosputum and frequent respiratory infections. Chest X-ray film and CT scan revealed a cyst with an intracystic solid mass in the left upper lung. Bronchogram demonstrated communication of the cyst with B5a and B5b bronchi. The left upper lobe was resected. Microscopic examination of the resected specimen revealed a mature teratoma of the lung. Teratoma of the lung is very rare. This case was diagnosed at surgery and was confirmed by microscopic examination.

Adult↗

PubMed1992

[A case of prolactinoma presenting with CSF rhinorrhea and CSF otorrhea during bromocriptine therapy].

Cerebrospinal fluid (CSF) leakage is a rare complication of prolactinoma treated with bromocriptine (BC). BC is known to be effective for reducing the volume of a prolactinoma and for decreasing the serum level of prolactin (PRL). In cases of pituitary tumors, CSF leakage is thought to be caused by shunting between the subarachnoid and extradural spaces. We had a case presenting with CSF rhinorrhea and CSF otorrhea during BC therapy which was treated successfully. The mechanism and treatment of CSF leakage were studied. A 55-year-old woman complaining of nasal obstruction and headache was admitted to our hospital on Nov. 22, 1988. CT scan showed a huge intracranial mass lesion involving the sella and the supra-sellar region and invading the sphenoid sinus and ethmoid sinus. Serum PRL level was 18,000 ng/ml. The patient was diagnosed as having an invasive prolactinoma, and BC therapy (5.0 mg per day) was instituted. Three days later, CSF rhinorrhea developed, and BC treatment discontinued; radiation therapy was started. After 36 Gy irradiation the size of the tumor was same on CT, and serum level of PRL was still high. The patient underwent trans-sphenoidal operation. The tumor was removed partially and the presumed CSF fistula was repaired. The sella and sphenoid sinus were packed with fat. BC treatment was reinstituted, and the serum PRL level decreased gradually without recurrent CSF rhinorrhea. Two weeks later the patient returned complaining of bilateral hearing disturbance. With a diagnosis of exudative otitis media she underwent bilateral tympanostomy. Immediately after tympanostomy, pulsating discharge from the middle ear was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Bromocriptine↗

PubMed1992

[Analysis of long-term social rehabilitation of brain contusion].

164 patients with brain contusion were evaluated with respect to social rehabilitation. 70 out of 134 patients (66.7%), said to have had good recovery or moderate disability by the Glasgow Outcome Scale (GOS), returned to full or partial employment. Factors such as age, Glasgow Coma Scale (GCS) at admission, duration of unawareness, fibrin and fibrinogen degradation product (FDP) were the most important in predicting social recovery. The Wechsler Adult Intelligence Scale (WAIS) was applied in 33 patients. The IQs of the patients who returned to their job fully tended to be higher than those who could not. In the majority of patients, impaired capacity for work was caused not only by physical deficits, but by mental retardation described as such as IQ score.

Adolescent↗

PubMed1992

[A case of granulomatous hypophysitis].

The patient was an unmarried, 25-year-old woman who presented herself with amenorrhea and lactation as her chief complaints. Radiography revealed a tumor in the sella turcica. Upon neurological examination at the time of admission, there were no abnormal findings affecting the field of vision or visual acuity, and no abnormalities were seen in the fundus oculi. In endocrinological tests, the basal plasma values of pituitary hormones were normal except for that of prolactin, which was 69.1 ng/ml. The preoperative diagnosis was nonfunctioning pituitary adenoma, and this neoplasm was resected by the transsphenoidal approach. Postoperative histological investigation showed vermiculous destruction of the anterior lobe of the pituitary gland, and also scattered lymph follicles accompanying infiltration by numerous lymphocytes and multinucleated foreign-body giant cells, and deposition of calcium. These findings, together with the epithelioid cells gathered around them, pointed to a diagnosis of granulomatous hypophysitis. The causes of granulomatous hypophysitis are known to include syphilis, tuberculosis, sarcoidosis, mycotic granuloma, and foreign-body granuloma due to the rupturing of a Rathke's cleft cyst, but no evidence of any of these was found in this patient. Another known source of inflammatory lesions in the hypophysis is lymphocytic hypophysitis, which resembles Hashimoto's autoimmune disease of the thyroid gland, and which is characterized both by the formation of lymph follicles and by extensive lymphocyte infiltration. In relation to the cause of granulomatous hypophysitis, thinking that it might possibly be an autoimmune disease, we conducted an immunological investigation, and also made a serological study of autoantibodies, but obtained no positive results.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

[Unsuspected painless subacute thyroiditis detected by radiogallium scintigraphy].

Two cases of painless subacute thyroiditis were presented in whom fever, fatigue and arthralgia except for thyroidal pain and swelling were complained. Until a intense uptake of the thyroid was found on radiogallium scintigraphy, the examinations of the thyroid had not been done. Laboratory data showed increased erythrocyte sedimentation rate, C-reactive protein and serum alkaline phosphatase, and mild leukocytosis. Skeletal, hepatic and biliary diseases were denied. In patients who have fever, increased erythrocyte sedimentation rate and serum alkaline phosphatase elevation without apparent sources, thyroid function should be evaluated because subacute thyroiditis can be associated with elevation of the serum alkaline phosphatase.

Gallium Radioisotopes↗

PubMed1992

Simultaneous estimation of blood flow rate and tissue temperature.

A new method for simultaneously estimating blood flow rate and tissue temperature under a RF hyperthermia treatment is presented. In this method the finite element method is used to solve the two-dimensional Laplace equation for a specific absorption rate (SAR) distribution and the two-dimensional bioheat transfer equation for a tissue temperature distribution from the SAR pattern over a cross-section of a patient-specific model input from computer tomography images. Blood flow rates used in the temperature distribution computation are determined from basal values given for respective types of tissues and tissue temperatures through an assumed function that is intended to represent the temperature dependence of the blood flow rate. The tissue temperature computation procedure is iterated until the estimated temperature at a given sampling point matches a measured value at that point. This iterative procedure allows one to simultaneously estimate blood flow rate and tissue temperature. This paper describes the numerical method along with results of rudimentary in vivo measurements made in a human brain, where blood flow rate was measured by the single photon emission computed tomography (SPECT) imaging technique and tissue temperature was measured by an invasive probe technique.

Blood Flow Velocity↗

PubMed1992

[A case report of a paraesophageal bronchogenic cyst and an esophageal cyst].

There are relatively few paraesophageal bronchogenic and esophageal cysts in mediastinal tumors. It is often difficult to distinguish between these cysts. Case 1: 11 year old, male with no symptoms. An abnormal tumor shadow was revealed by chest roentgenogram. Before operating, CT, MRI and other laboratory tests were suggested that the tumor was neurogenic. A cyst with a pedicle connected to the esophageal muscle layer was found during the operation. Pathological examination confirmed a bronchogenic cyst lined with cartilage. Case 2: 38 year old female with epigastralgia. Upper gastrointestinal series revealed that the thoracic esophagus was smoothly compressed from the outside. CT and MRI showed a well-defined cystic mass in the posterior mediastinum. The cyst bordered the esophagus, but there was no direct communication between them. The pathological findings showed the presence of a double layer of smooth muscle without cartilage which was diagnosed as an esophageal cyst.

Adolescent↗

PubMed1992

[Coronary artery disease in diabetic patients].

Although it is well known that diabetics have high mortality rates due to ischemic heart disease (IHD), controversies still exist about the severity of coronary artery disease in diabetics compared to nondiabetics. We compared coronary arteriographies of 50 diabetics with IHD to those of 50 nondiabetics with IHD. In regard to coronary risk factors, incidence of obesity was significantly higher in diabetics. Incidence of hypertension, hypercholesteremia, hyperuricemia was higher, although not significant, in diabetics. Incidence of smoking was significantly higher in nondiabetics. The diabetic group showed a significantly higher incidence of patients with more than two or three diseased vessels, and a significantly higher number of diseased coronaries with more than 50% stenosis per patient compared to nondiabetics (5.6 +/- 3.7 vs 3.7 +/- 3.2). The distribution of diseased coronaries with more than 75% stenosis showed no difference between diabetics and nondiabetics. The incidence of coronary spasm was significantly lower in diabetics (12% vs 28%). The high incidence of multiple vessel disease in diabetics was thought to be due to other complicated coronary risk factors, especially hypertension and hypercholesteremia.

Aged↗

PubMed1992

[Diagnosis and treatment of disseminated intravascular coagulation associated with neurosurgical diseases; a proposal of a new scoring system for DIC].

The occurrence of disseminated intravascular coagulation (DIC) is not rare in neurosurgical patients. We investigated the therapeutic effects of gabexate mesilate (FOY) for DIC or DIC preparatory state in 70 cases. Underlying diseases were head injuries in 31 cases, intracranial hemorrhages in 19, subarachnoid hemorrhages in 10, cerebral infarctions or embolisms in 5, brain tumors in 3 and other diseases in 2. DIC or DIC preparatory states were induced by severe brain damage (26 cases), infection (26 cases), failure of other organs (6 cases), shock (5 cases), and others. On the basis of the clinical coagulation studies of these patients, we retrospectively established a new scoring system for DIC (neurosurgical DIC score) associated with neurosurgical diseases and evaluated whether it was useful. Because the original DIC score proposed by the Research Committee on Blood Coagulation Disorders supported by the Japanese Ministry of Health and Welfare was not correlated with the level of consciousness representing the primary brain damage, it was likely to be underestimated in neurosurgical patients. Therefore, we included the level of consciousness with a new DIC scoring system. The neurosurgical DIC score was calculated from platelet count (score 0-3), FDP (score 0-3) and the level of consciousness (score 0-2), and was diagnosed as DIC preparatory state if it was 3, calculated from 2 of the 3 parameters, and as DIC if it was over 4. The score should be checked twice if it was 3, especially after operation. The neurosurgical DIC score was significantly correlated with the original DIC score.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1991

Evolution of tRNAs and tRNA genes in Acholeplasma laidlawii.

The genes for 22 tRNA species from Acholeplasma laidawii, belonging to the class Mollicutes (Mycoplasmas), have been cloned and sequenced. Sixteen genes are organized in 3 clusters consisting of eleven, three and two tRNA genes, respectively, and the other 6 genes exist as a single gene. The arrangement of tRNA genes in the 11-gene, the 3-gene and the 2-gene clusters reveals extensive similarity to several parts of the 21-tRNA or 16-tRNA gene cluster in Bacillus subtilis. The 11-gene cluster is also similar to the tRNA gene clusters found in other mycoplasma species, the 9-tRNA gene cluster in M.capricolum and in M.mycoides, and the 10-tRNA gene cluster in Spiroplasma meliferm. The results suggest that the tRNA genes in mycoplasmas have evolved from large tRNA gene clusters in the ancestral Gram-positive bacterial genome common to mycoplasmas and B.subtilis. The anticodon sequences including base modifications of 15 tRNA species from A.laidlawii were determined. The anticodon composition and codon-recognition patterns of A.laidlawii resemble those of Bacillus subtilis rather than those of other mycoplasma species.

Acholeplasma laidlawii↗

PubMed1991

von Recklinghausen neurofibroma produces neuronal and glial growth-modulating factors.

Two kinds of novel neural trophic factors were currently detected in von Recklinghausen neurofibroma (NF1) extracts. One of the two was a growth factor, neuroblastoma growth factor (Mr less than 5 kDa), which promotes the proliferation of human neuroblastoma cell and survival and neurite-extension of rat cortical neurons, but differently from nerve growth factor (NGF) or NGF-like factors. The other one was a glial growth inhibitor (Mr = 100 kDa), which suppresses the growth of glioma cell lines, astrocytoma, glioblastoma, oligodendroglioma and Schwannoma. These factors do not appear to be previously identified cytokines or growth factors such as interleukins, granulocyte colony-stimulating factor, NGF and fibroblast growth factor. There was also detectable ciliary neurotrophic factor-like activity in the extracts. The primary cause of high contents of these factors in NF1 is not known, but may relate to fundamental mechanisms controlling growth and differentiation of neurons and glias during development of nervous system.

Animals↗

PubMed1991

Occurrence of an active form of gelatinase in human gastric and colorectal carcinoma tissues.

Profiles of gelatinase released during 4 h incubation of explants from human carcinoma tissues (15 gastric and 15 colorectal carcinomas) in serum-free RPMI 1640 medium were compared with those of corresponding normal tissue specimens obtained 2 and 10 cm apart from tumor periphery. All the culture supernatants of both tumor and normal tissues contained gelatinase species of 200, 130, 92 and 72 kDa as detected by zymography with gelatin as a substrate. Besides these gelatinase species, all carcinoma tissue culture supernatants had an additional 66-kDa gelatinase, an active form of the 72-kDa gelatinase. This gelatinase was not detectable in the normal tissues 10 cm apart from the tumor mass, with an exceptional case of gastric carcinoma of Borrmann type 4. These results suggest that the presence of active form of gelatinase might be one of the characteristic properties of these malignant human tumors.

Colorectal Neoplasms↗

PubMed1991

Reciprocal Ia inhibition in patients with spinal spasticity.

Reciprocal Ia inhibition from ankle flexors to extensors was studied in five patients with spasticity due to incomplete traumatic spinal cord lesions. Nine healthy subjects were tested as controls. Excitability of the soleus motoneuron pool was estimated by H-reflex testing in the resting state. Ia inhibition was activated by conditioning stimuli to the peroneal nerve. Ia inhibition was detected in all patients tested, the amount of inhibition ranging from 8% to more than 50% of the test H-reflex size. In the control subjects only weak Ia inhibitory effects were present. These findings indicate increased excitability of the Ia inhibitory pathway to ankle extensor motoneurons in patients with spasticity due to spinal cord injury.

Adult↗

PubMed1991

Structure and chromosome assignment of human S100 alpha and beta subunit genes.

The human S-100 alpha and beta subunit genes were isolated from human genomic DNA library. The restriction endonuclease mapping and DNA sequencing analysis revealed that both subunit genes consisted of three exons and two introns. Two Ca2(+)-binding domains were independently encoded by exon 2 and exon 3. Spot-blot hybridization analysis with flow-sorted chromosomes showed that human alpha and beta subunit genes were assigned to chromosome 1 and chromosome 21, respectively.

Amino Acid Sequence↗