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Biomedical subjects

H Tokunaga

Publications and source records attributed to H Tokunaga.

At least 37 records · Page 2Linked to original sources
PubMed2001

Conflict of intentions due to callosal disconnection.

OBJECTIVES: Three patients with callosal syndrome manifested a peculiar symptom in that they were unable to perform intended whole body actions because another intention emerged in competition with the original one. Attempts were made to clarify the symptomatology of this manifestation and its possible mechanism is discussed. METHODS: The three patients are described and previous reports on patients with callosal damage were reviewed. Four additional patients with similar symptoms were found and the clinical features common to all seven patients were examined. RESULTS: This symptom could not be attributed to unilateral movement disorders such as unilateral apraxia, intermanual conflict, or compulsive manipulation of tools. The manifestations included marked hesitation in initiating actions, interruption of actions, repetitive actions, and performance of unintended actions with difficulty in correcting them. All patients, except one, had a lesion in the posterior half of the body of the corpus callosum, and there was no significant involvement of the cerebral cortex. The symptom became manifest later than 4 weeks after callosal damage. It occurred during spontaneous actions, but not during well automated actions nor when following instructions. CONCLUSION: This symptom, tentatively named "conflict of intentions", can be regarded as a fragment of diagonistic dyspraxia originally described by Akelaitis, although it can occur independently of intermanual conflict. Normally, the right and left cerebral hemispheres may be complementarily modifying automated whole body actions in order to adapt behaviour to changes of the environment as well as to the intention. Partial callosal disconnection without significant cortical involvement would exaggerate the disparity between the role of each hemisphere through the reorganisation of neural systems after callosal damage. Such double, often contrary, behavioural tendencies may sometimes simultaneously enter the patient's awareness.

Adult↗
PubMed2001

Endothelin receptor antagonist prevents parathyroid cell proliferation of low calcium diet-induced hyperparathyroidism in rats.

Secondary hyperparathyroidism, one of the most frequently encountered disorders of the calcium homeostasis, is characterized by an increase in parathyroid epithelial (PT) cell number, which is crucial from a functional viewpoint. However, it is still unknown what factors are involved in PT cell proliferation. Endothelin-1 (ET-1), a vasoconstrictive peptide, has been shown to act as a mitogen in a variety of cell types. Rat PT cells are reported to synthesize ET-1 and possess its receptors. To test the hypothesis that ET-1 plays a role in PT cell proliferation, we used rat test subjects fed a low calcium diet for 8 weeks (low Ca rats). The number of the proliferating PT cells, measured by proliferating cell nuclear antigen immunostaining, was significantly increased, with striking immunoreactivity of ET-1 in the low Ca rats. An endothelin receptor antagonist, bosentan (100 mg/kg.day), prevented any increase in the proliferation of PT cells in the low Ca rats (14.3 +/- 2.7/1000 PT cells with no bosentan; 2.1 +/- 1.3 with bosentan; P < 0.01). These results indicate that ET-1 is involved in PT cell proliferation in vivo and suggest that blocking of ET receptors may become one of the important therapeutic strategies for preventing secondary hyperparathyroidism.

Animals↗
PubMed2001

Molecular cloning of groESL locus, and purification and characterization of chaperonins, GroEL and GroES, from Bacillus brevis.

The groESL locus of a protein-hypersecreting bacterium, Bacillus brevis, was cloned by PCR using primers designed based on the DNA sequence of a B. subtilis homolog. GroEL protein was purified to apparent homogeneity and its ATPase activity was characterized: it hydrolyzed ATP, CTP, and TTP in this order of reaction rate, and its specific activity for ATP was 0.1 micromole/min/mg protein. Purified GroEL forms a tetradecamer. GroEL was estimated to contain 22% alpha-helix, 24% beta-sheet, and 19% turn structures, by CD measurement. GroES protein was also highly purified to examine its chaperonin activity. GroEL protected from thermal inactivation of and showed refolding-promoting activity for malate dehydrogenase, strictly depending on the presence of ATP and GroES.

Adenosine Triphosphatases↗
PubMed2001

Characterization of nucleoside diphosphate kinase from moderately halophilic eubacteria.

Nucleoside diphosphate kinase was purified to apparent homogeneity from naturally isolated moderately halophilic eubacteria by ATP-agarose and phenyl-5PW column chromatographies. The molecular mass of this enzyme was 15 kDa by time-of-flight mass-spectrometry. This protein showed anomalous mobility on SDS-PAGE which is typical of a halophilic protein. It was stable and active over a wide range of salt concentrations, from 0 to 4.0 M NaCl.

Amino Acid Sequence↗
PubMed2001

Reappraisal of the historic 1959 cat experiment in Minamata by the Chisso Factory.

Autopsy specimens from the historic cat experiment were recently discovered in a storage area at the Kumamoto University School of Medicine. The specimens were from an experiment prompted by physicians in the Chisso Minamata Plant following the announcement made by the Study Group for Minamata disease. On July 14, 1959 the Group announced that the disease was most likely caused by a kind of organic mercury. In order to prove or disprove that industrial waste from the Chisso Factory was the culprit in Minamata disease, a total of ten cats were fed food mixed with industrial waste produced in the acetaldehyde-producing plant. One of the ten cats, No. 717, was subsequently autopsied but the autopsy findings have never been published or recorded in the literature despite their historic significance. The rediscovered specimens were studied pathologically and biochemically, and were analyzed chemically with currently available techniques. Characteristic lesions of methylmercury poisoning were observed in the central nervous system, and the mercury levels in the cerebrum, cerebellum, liver and kidney were found to be markedly elevated in this animal.

Animals↗
PubMed2001

Glomerular endothelial cells are maintained by vascular endothelial growth factor in the adult kidney.

Vascular endothelial growth factor (VEGF) is known to maintain endothelial cells of immature vessels and is constitutively expressed in the kidney from the embryo to adult. We tested the hypothesis that VEGF activity is needed to maintain glomerular endothelial cells in the adult. Neutralizing antibody to VEGF165 was intraperitoneally administered to mice for 3 days to strongly suppress its intrinsic activity. On the fourth day, mice were sacrificed and tissues were examined by light and electron microscopies. Vascular casts of renal vessels were observed by a scanning electron microscopy. Distribution of the administered antibody and expressions of VEGF and Flk-1 were examined immunohistochemically. The suppression of endogenous VEGF activity caused swelling and vacuolation of endothelial cells and obstruction of capillaries in the glomerulus. Other tissues were not impaired significantly. The administered antibody was specifically localized to the glomerulus, and was found more predominantly in the juxta-medullary than in the cortical glomerulus. This pattern of antibody deposition was similar to that of Flk-1. VEGF expression in the glomerulus was compensatively elevated by the antibody treatment. These results show that demand for VEGF signaling in the glomerulus is much higher than in other tissues, probably to protect its endothelial cells against high tension for blood filtration. This demand may be fulfilled by enriched signaling through the Flk-1 in the glomerulus.

Animals↗
PubMed2001

Association of plasma homocysteine concentrations with carotid atherosclerosis in elderly Japanese.

OBJECTIVE: Homocysteine (Hcy) is a sulfhydryl amino acid. Its precursor, the essential amino acid methionine, is derived from dietary protein; recently a number of studies have suggested its relation to atherosclerosis. The present study was performed to clarify the relation between the plasma Hcy concentration and sclerotic lesions of the common carotid arteries. METHODS AND PATIENTS: We evaluated sclerotic lesions of common carotid arteries by ultrasonography in 120 elderly in-patients (77+ /- 9 years), and studied the relationship of the known risk factors for atherosclerosis including plasma Hcy. An ultrasonograph and 7.5 MHz linear type B-mode probe were used by a specialist to evaluate sclerotic lesions of the common carotid arteries. Blood was drawn from the patients while fasting for determination of plasma Hcy. Plasma Hcy concentrations were determined using a high-performance liquid chromatography assay. RESULTS: Logistic regression analysis using IMT as an object variable, adjusted by various risk factors including the plasma Hcy concentration, revealed that the relative risk in the group combining the second and the third highest Hcy groups was 6.49 (95% confidence interval (CI): 1.95-21.9) compared with the first group and the plaque presence showed a relative risk of 4.45 (95% CI: 1.53-12.9). CONCLUSION: The findings of this study confirmed that observations of an association between plasma Hcy concentration and common carotid atherosclerosis in Western populations is also present among the elderly Japanese.

Aged↗
PubMed2001

An association between an antibody against Chlamydia pneumoniae and common carotid atherosclerosis.

OBJECTIVE: Chlamydia pneumoniae (C. pneumoniae) is an important pathogen for infections of the respiratory tract, and there are recently also a number of reports suggesting its relation with atherosclerosis. This study was performed to clarify the relation between C. pneumoniae infection and sclerotic lesions of the common carotid arteries. METHODS AND PATIENTS: We evaluated sclerotic lesions of common carotid arteries by ultrasonography in 147 in-patients (mean age, 70 years; 95% confidence interval, 68-72) in the internal medicine ward, and studied the relation of the known risk factors for atherosclerosis including C. pneumoniae infection. An ultrasonograph and 7.5 MHz linear type B-mode probe were used by a specialist to evaluate sclerotic lesions of common carotid arteries. C. pneumoniae infection was determined by measuring anti-C. pneumoniae IgG specific antibody level (IgG index) using enzyme-linked immunosorbent assay (ELISA) method with serum of fasting blood, which had been preserved at -70 degrees C. RESULTS: IgG index (p=0.0263), from multiple regression analysis using various risk factors as explanatory variables, was a significant independent contributing factor (R2=0.3465, p<0.0001) along with known risk factors such as male (p=0.0289), age (p=0.0007), Brinkman index (p=0.0067), hypertension (p=0.0443) and T-Chol (p=0.0220). CONCLUSION: This study confirmed that the observations of an association between antibody against C. pneumoniae and common carotid atherosclerosis in Western nations is also present in Japan. Our results suggests that C. pneumoniae infection is also an important risk factor for common carotid atherosclerosis.

Adult↗
PubMed2001

[A case of congenital hydronephrosis suffering from rupture of the renal pelvis due to trauma].

A 19-year-old male patient was admitted with the chief complaint of left abdominal pain. After receiving a mild punch in the abdomen during boxing exercises, he had severe abdominal pain and was brought to an emergency room. Since abdominal CT scanning revealed the retention of massive fluid in the retroperitoneum, hydronephrotic rupture due to the trauma was diagnosed and nephrectomy was performed. The removed kidney was filled as a result of urinary retention, and congenital hydronephrosis accompanied by the ureteropelvic junction obstruction was macroscopically and pathohistologically diagnosed. Postoperative course was favorable and the patient was discharged on the 10th hospital day.

Adult↗
PubMed2001

Toward a tobacco-free society in Japan.

Tobacco is one of the major preventable causes of death and disability. This is widely known in both Japan and the USA, and although the smoking rate in the USA is decreasing, that in Japan remains high. The tobacco histories of these two countries, which provide the background to this difference, are herein compared. The antismoking movement is becoming more vociferous in both countries. Publicity regarding of the dangers of smoking, warning signs on tobacco packages, the introduction of antismoking devices, a ban on commercials for tobacco-related products on TV and the radio, no-smoking seats on airplanes, and litigation against the tobacco industry have all been introduced. However, major differences remain between these two countries. The tobacco industry in the USA has been a private company since it was first established. Courts have ordered the tobacco industry to pay compensation for damage to health resulting from tobacco. Smoking is strictly restricted inside buildings. Advertisements for nicotine gum and nicotine patches and reports on the dangers of smoking are regularly broadcast. In the case of Japan, the government at first nationalized the tobacco industry, and then made it a private company, although the government still holds two-thirds of its stock. Moreover, it established the Tobacco Business Law to support the company. The main purpose of antismoking campaigns in Japan is a partial ban on smoking. On the basis of these differences between the two countries regarding the history of tobacco, the antismoking movement in Japan has yet to choose which path to take.

Government↗
PubMed2001

[Lymphedema after radical prostatectomy: a case report].

We report a case of intractable lymphedema of the left leg following radical prostatectomy. The 69-year-old male patient complained of difficulty walking, caused by severe lymphedema. Intraarterial autologous lymphocyte transfusion therapy was performed because of failure of conventional conservative therapy, and the leg edema resolved almost completely. However, the treatment did not improve the penoscrotal edema necessitating excision of the edema and skin graft in a separate procedure. The post-operative course was excellent and the patient's performance status improved to 1 from 3.

Aged↗
PubMed2001

[A patient with neuroborreliosis presenting gadolinium-enhanced MRI lesions in bilateral facial nerves].

We report a 33-year-old man with bilateral facial paralysis due to neuroborreliosis. About three weeks after rhinorrhea and fever lasting four days, he noticed fatigue in the legs and paresthesia in all four extremities. Another week later, he developed paresthesia in his tongue and bilateral facial muscle weakness, and was admitted to our hospital. On admission, neurological examination revealed moderate bilateral facial muscle weakness, mild paresthesia in the tongue and four extremities, and decreased Achilles tendon reflex bilaterally. Mild pleocytosis and increased protein were found in the cerebrospinal fluid (CSF). IgM antibodies that reacted with the antigens of Borrelia garinii and Borrelia afzelii were found in his serum. Clinically and serologically, he was thus diagnosed as having neuroborreliosis. Brain MRI revealed gadolinium-enhanced lesions of the bilateral facial nerves in the facial nerve canal portion. After three weeks of treatment with 100 mg/day doxycycline and 2 g/day ceftriaxone sodium, his symptoms and CSF abnormalities were rapidly improved. Although facial nerve paralysis is a major symptom of neuroborreliosis, the present report is the first to detect the inflammatory lesions of the facial nerves in the facial nerve canal portion by MRI.

Adult↗
PubMed2000

Functional anatomical study of psychogenic amnesia.

Psychogenic amnesia is characterized by an inability to recall information already stored in the patient's memory. It is usually related to a stressful or traumatic event that cannot be explained by manifest brain damage. To examine the underlying functional disturbance of brain areas in this condition, we performed a positron emission tomography (PET) activation study on a psychogenic amnesic patient and on 12 normal control subjects. A task requiring explicit retrograde memory of faces was compared with a control task. To assess functional modifications associated with the processes of recovery, a second PET study was performed on the patient 12 months after onset. During the task, activation of the right anterior medial temporal region including the amygdala was increased in the psychogenic amnesic patient. Activation of the bilateral hippocampal regions increased only in the control subjects. During recovery, the right anterior medial temporal region became less active while the right hippocampal region became more active. Activation levels also differed in the anterior cingulate cortex, prefrontal cortex and some other cortical regions between control subjects and the patient. These findings suggest that the changes in these limbic and limbic-cortical functions are related to symptoms of the psychogenic amnesia.

Adult↗
PubMed2000

Expression of bone morphogenetic protein receptors type-IA, -IB and -II correlates with tumor grade in human prostate cancer tissues.

Bone morphogenetic proteins (BMPs) are potential regulators of prostate cancer cell growth and metastasis that signal through an interaction with BMP membrane receptors (BMPRs) type I and type II. In the present study, Western blot and immunohistochemical analysis of BMPRs were carried out in benign and malignant human prostate tissues to explain the loss of BMP response in human prostate cancer cells. The results demonstrated that the benign prostate specimens expressed high levels of all three BMPRs. In normal prostate, BMPRs were localized predominantly to epithelial cells. Among prostate cancer specimens, well-differentiated cancers were positive for the expression of BMPR-II, BMPR-IA, and BMPR-IB, for the most part. In contrast, only 1 of 10 poorly differentiated prostate cancer cases was positive for each of the three BMPRs (P < 0.005 for all three receptors). Taken together, these results indicate that human prostate cancer cells frequently exhibit loss of expression of BMPRs and suggest that loss of BMPRs may play an important role during the progression of prostate cancer.

Blotting, Western↗
PubMed2000

The neural basis of perceptual and conceptual word priming--a PET study.

Positron emission tomography scans were obtained in 13 normal subjects during perceptual and conceptual word priming tasks with the aim to investigate the neural system specific to the two priming conditions. In the prescan phase, subjects were primed perceptually or conceptually with two separate procedures, while in the scan phase, they performed the same stem completion task. Therefore we could compare the results of the two priming tasks in a direct manner. A fixation control task and a baseline task (completion of stems that did not correspond to previously seen words) were also given. A specific blood flow decrease was found in the left inferior temporal cortex in the perceptual word priming condition and in the left superior temporal / inferior parietal cortex in the conceptual word priming condition. Each blood flow change may reflect transient changes in the cortical areas subserving the processing of the perceptual and conceptual components of word priming.

Adult↗
PubMed2000

Growth hormone secreting adenoma with unusual extension: coexisting pituitary cyst and its clinical significance.

A 58 year old man showed acromegalic features. The serum growth hormone (GH) level was 7.3 ng/ml and SMC (somatomedin-C) 637 U/ml. Triple stimulation test showed abnormal response compatible with a GH secreting tumour. The conventional enhanced MRI revealed a less enhanced hemisphere-shaped lesion at the right corner of the sella turcica. In addition, dynamic MRI demonstrated an elongated lesion extending to the left beyond the midline. The patient underwent transsphenoidal surgery. Besides the soft and suckable tumour at the right corner, we entered into a small cavity loosely filled with the tumour, which was subsequently also removed. The operative finding corresponded to the lesion shown in dynamic MRI. Postoperative GH and SMC levels became 2.3 ng/ml and 326 U/ml respectively. Incidental pituitary cystic lesions in autopsied cases have been reported to be 6-33%. This case had a GH secreting adenoma with coexisting pituitary cyst. The coexisting pituitary cyst supposedly influenced the unusual shape and extension of the pituitary adenoma. Coexistence of such lesion should be kept in mind for microadenoma on neuroradiological evaluation and on intraoperative inspection surrounding the tumour.

Adenoma↗
PubMed2000

Secretion of hen egg white lysozyme from Kluyveromyces lactis.

Hen egg white (HEW) lysozyme was correctly processed and efficiently secreted from an alternative yeast, Kluyveromyces lactis. We constructed secretion vectors using PHO5, PGK, and LAC4 promoters, and found that the highest secretion was obtained under the direction of the PGK promoter in non-selective rich medium. K. lactis secreted HEW lysozyme with two-fold higher efficiency than S. cerevisiae, estimated by using a K. lactis-S. cerevisiae shuttle vector.

Animals↗