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Biomedical subjects

K Tashima

Publications and source records attributed to K Tashima.

At least 37 records · Page 2Linked to original sources
PubMed1999

Cortical potentials preceding voluntary finger movement in patients with focal cerebellar lesion.

OBJECTIVE: To elucidate influences of the dentate nucleus on the generation of the related cortical potentials (MRCPs) preceding voluntary movement, Bereitschaftspotential (BP) and negative slope (NS). DESIGN AND METHODS: MRCPs preceding self-paced voluntary finger movement were recorded in 5 cases with localized cerebellar lesions due to stroke or tumor. Comparing 3 of them involving the dentate nucleus and 2 others sparing it, as judged from CT or MRI findings. RESULTS: BP and NS preceding voluntary finger movement ipsilateral to the lesion were absent or markedly reduced in amplitude in those 3 cases with the dentate nucleus lesion, whereas those negative components were present in the 2 cases with no evidence of dentate lesion. CONCLUSION: The dentate nucleus has a facilitatory effect on the generation of BP and NS.

Adult↗
PubMed1999

Variant transthyretin (TTR) amyloidosis in Argentina. Detection of the trait by electrospray ionization mass spectrometry of lyophilized TTR immunoprecipitate.

We have developed a quick and reliable diagnostic method for detecting variant forms of transthyretin (TTR); namely, centrifugal concentration followed by electrospray ionization mass spectrometry (ESI-MS). Argentinian patients from three families with neuropathic amyloidosis and their relatives were screened for mutated TTR by ESI-MS. In order to facilitate transportation, we investigated the impact storage had on lyophilized anti-TTR-antibody precipitates' mass spectra. For this investigation, plasma samples from three Swedish patients with known TTR amyloidosis were analysed. We detected identical, additional peaks corresponding to a variant form of TTR in 10 members of the families, and also in a lyophilized sample sent unfrozen by mail from Argentina. All except one symptomatic subject had additional peaks, the exception having undergone a liver transplantation for the disease. All patients were early onset cases, i.e. below 35 years of age, and family history suggests an aggressive, rapidly progressing disease. Lyophilized anti-TTR-antibody precipitates stored at room temperature for 1 week exhibited only minor differences compared with plasma samples stored at -70 degrees C. In a new Argentinian study on familial amyloidotic polyneuropathy, the variant TTR was quickly identified and typed by ESI-MS. To facilitate transportation, dry-frozen samples can be used and the quality of the spectra is similar to that of samples stored at -70 degrees C.

Adolescent↗
PubMed1999

Identification of a new transthyretin variant (Ile49) in familial amyloidotic polyneuropathy using electrospray ionization mass spectrometry and nonisotopic RNase cleavage assay.

Mutation of the transthyretin (TTR) plasma protein and gene in a Japanese patient with amyloid polyneuropathy was investigated by electrospray ionization mass spectrometry (ESI-MS) and nonisotopic RNase cleavage assay (NIRCA), respectively. ESI-MS analysis showed normal TTR peaks and additionally a variant TTR with 12-dalton-higher molecular weight than normal TTR. NIRCA suggested that the mutation existed near either the 5' or 3' end of exon 3. Direct DNA sequencing revealed both a normal ACC (threonine) and a variant ATC (isoleucine) at codon 49, which was located near the 5' end of exon 3. The molecular weight shift of this mutation was 12 D, consistent with the result of ESI-MS.

Aged↗
PubMed1999

Gastrointestinal dysfunction in familial amyloidotic polyneuropathy (ATTR Val30Met)--comparison of Swedish and Japanese patients.

The aim of the present study was to compare the clinical symptoms of Swedish and Japanese patients with familial amyloidotic polyneuropathy (ATTR Val30Met), especially gastrointestinal disturbances, and to correlate the findings with survival. Seventy-three Swedish and 47 Japanese patients were available for the study. Thirty-two Swedish and 7 Japanese patients had undergone liver transplantation. The mean age at onset was 50 for Swedish and 35 for Japanese patients (P < 0.001; non-transplanted patients). Fifty-five percent of Japanese patients had gastrointestinal disturbances from onset, compared to 22% of Swedish patients (P < 0.05; whole population). The Swedish patients average survival after the onset was significantly longer than Japanese patients (P < 0.05; non-transplanted patients). An early onset of gastrointestinal symptoms was correlated to a decreased survival for Swedish, but not for Japanese patients. Age at onset was not correlated to survival neither for Swedish nor for Japanese patients. We conclude that the clinical expressions of familial amyloidotic polyneuropathy ATTR Val30Met are different in Swedish and Japanese patients. The survival after the onset was shorter for Japanese patients, who also had an earlier onset of gastrointestinal disturbances, especially diarrhea than Swedish patients.

Adolescent↗
PubMed1999

Impact of age and amyloidosis on thiol conjugation of transthyretin in hereditary transthyretin amyloidosis.

Variant forms and post-translational modifications of transthyretin (TTR) can be identified by electrospray ionisation mass spectrometry (ESI-MS). The aim of the present study was to investigate thiol conjugation of transthyretin and it's relation to age and symptomatic amyloid disease in different populations of variant TTR carriers. Plasma samples from 70 individuals from Denmark, Argentina, Sweden and Japan, with 2 different TTR mutations were analysed. The percentage cysteine (Cys) conjugated wild and variant TTR were calculated from the corresponding peaks of the spectra, and multiple regression analysis was employed to disclose relationships between age, symptomatic amyloid disease and origin. Age, origin and presence of symptomatic disease, were found to be independent factors related to transthyretin conjugation. A higher percentage of conjugated to unconjugated TTR was disclosed in symptomatic, but not in asymptomatic carriers. In summary: Thiol conjugation of TTR is dependent on age and presence of symptomatic amyloid disease. Furthermore, it varies between different populations. Variant TTR is more susceptible to thiol conjugation than the wild type. Post-translational factors may be related to amyloid formation and/or toxicity.

Adolescent↗
PubMed1998

An atypical case of adult Moyamoya disease with initial onset of brain stem ischemia.

We present an atypical case of adult moyamoya disease whose clinical onset consisted of ischemic symptoms of the brain stem. She initially presented with left hemisensory disturbance caused by a pontine lesion, followed by a myelopathy of the upper cervical spinal cord. Eight months later, she presented with left hemiplegia and disturbed consciousness. Magnetic resonance angiography showed significant narrowing of both horizontal portions of the middle cerebral arteries (M1). Conventional angiography revealed bilateral occlusion of the internal carotid arteries. Her anterior circulation was supplied from the vertebro-basilar system through Moyamoya vessels and leptomeningeal collaterals. The intracranial steal phenomenon was thought to be the reason for the preceding events in the brain stem and upper cervical spinal cord. In addition, transcranial color-coded duplex sonography (TCCS) showed identical findings to conventional angiography with antegrade flow in the proximal M1 and retrograde flow in the distal M1. Thus, TCCS was useful for diagnosing the M1 occlusion in this case of Moyamoya disease.

Anastomosis, Surgical↗
PubMed1998

Familial amyloidotic polyneuropathy type I with extracellular superoxide dismutase mutation: a case report.

We report an autopsy case of familial amyloidotic polyneuropathy (FAP) Type I with mutations in both transthyretin (TTR) and extracellular superoxide dismutase (EC-SOD). This patient started to develop peripheral neuropathy at age 25, followed by cardiac, renal, and autonomic nervous system failure due to massive amyloid deposition. Thirteen years after the initial symptoms, he died of septic shock. Autopsy revealed suppurative peritonitis, multiple abscesses in the bile ducts and urinary tract, and more marked amyloid deposition than commonly seen in FAP. Amyloid deposition occurred in various organs and tissues, especially prominently around blood vessels and in interstitial tissues, and was demonstrated immunohistochemically to be composed of TTR but not amyloid A (AA) and not amyloid L (AL) proteins. The serum EC-SOD content of the patient was 10 fold higher than those seen often in other FAP patients and in healthy controls. Genetic analysis demonstrated the single amino acid substitutions in Val30Met TIR and Arg213Gly EC-SOD. Since these data suggest the dissociation of EC-SOD from the vascular wall, massive amyloid deposition in the present case may be related to increased oxidative stress in loco.

Adult↗
PubMed1998

Increased susceptibility of gastric mucosa to ulcerogenic stimulation in diabetic rats--role of capsaicin-sensitive sensory neurons.

1. We examined the gastric mucosal blood flow (GMBF) and ulcerogenic responses following barrier disruption induced by sodium taurocholate (TC) in diabetic rats and investigated the role of capsaicin-sensitive sensory neurons in these responses. 2. Animals were injected streptozotocin (STZ: 70 mg kg(-1), i.p.) and used after 5, 10 and 15 weeks of diabetes with blood glucose levels of > 350 mg dl(-1). The stomach was mounted on an ex-vivo chamber under urethane anaesthesia and exposed to 20 mM TC plus 50 mM HCl for 30 min in the presence of omeprazole. Gastric transmucosal potential difference (PD), GMBF, and luminal acid loss (H+ back-diffusion) were measured before and after exposure to 20 mM TC, and the mucosa was examined for lesions 90 min after TC treatment. 3. Mucosal application of TC caused PD reduction in all groups; the degree of PD reduction was similar between normal and diabetic rats, although basal PD values were lower in diabetic rats. In normal rats, TC treatment caused luminal acid loss, followed by an increase of GMBF, resulting in minimal damage in the mucosa. 4. The increased GMBF responses associated with H+ back-diffusion were mitigated in STZ-treated rats, depending on the duration of diabetes, and severe haemorrhagic lesions occurred in the stomach after 10 weeks of diabetes. 5. Intragastric application of capsaicin increased GMBF in normal rats, but such responses were mitigated in STZ diabetic rats. The amount of CGRP released in the isolated stomach in response to capsaicin was significantly lower in diabetic rats when compared to controls. 6. The deleterious influences on GMBF and mucosal ulcerogenic responses in STZ-diabetic rats were partially but significantly antagonized by daily insulin (4 units rat(-1)) treatment. 7. These results suggest that the gastric mucosa of diabetic rats is more vulnerable to acid injury following barrier disruption, and this change is insulin-sensitive and may be partly accounted for by the impairment of GMBF response associated with acid back-diffusion and mediated by capsaicin-sensitive sensory neurons.

Animals↗
PubMed1998

Effects of diabetes mellitus on the contractile activity of carbachol and galanin in isolated gastric fundus strips of rats.

The role of the cholinergic and peptidergic pathways in the impairment of gastric motility associated with diabetic gastroparesis was assessed at the postsynaptic level using isolated fundus smooth muscle strips. Maximal contractile responses to carbachol and galanin were significantly decreased in fundus strips isolated from rats rendered diabetic by a single intraperitoneal injection of streptozotocin (STZ, 70 mg/kg) 1, 4 and 8 weeks before experiments. We also observed notable decrements in the slopes and Hill's coefficients without conspicuous changes in the EC50 of the respective galanin concentration-response curves measured in strips obtained from STZ animals after 4 and 8 weeks. L-NAME reversed the above-mentioned alterations in an L-arginine-sensitive manner in STZ rats after 4 weeks but not in STZ rats after 8 weeks. The blood plasma nitrite/nitrate levels in STZ animals after 4 and 8 weeks were increased by 44.6 and 61.9%, respectively. Ca2+-independent nitric oxide synthase activity in gastric fundus strips and stomach corpus mucosa from STZ rats after 4 weeks was markedly enhanced by 37.4 and 31.9%, respectively, suggesting an enhanced nitric oxide production. In vivo insulin treatment prevented diabetes-induced alterations in smooth muscle contractility. We conclude that the smooth muscle dysfunction evoked by experimental diabetes causing diminished contractions of fundus strips to carbachol and galanin is at least partly due to the increased nitric oxide synthesis.

Animals↗
PubMed1997

Down regulation of a harmful variant protein by replacement of its normal protein.

To compensate for the hypoprotein and hypoalbuminemia of familial amyloidotic polyneuropathy (FAP) patients, 800 ml of fresh frozen plasma (FFP) was intravenously administered and change in total and variant transthyretin (TTR) levels were measured in the plasma. After injection of FFP, total plasma TTR levels were elevated and variant TTR levels decreased from 24 to 48 h, accompanied by an elevation of plasma total protein, albumin levels and TTR levels. To elucidate the mechanism of this phenomenon, a large amount of purified normal TTR from normal human plasma was intravenously injected in mice and FAP patients. By intravenous injection of 3 mg of the purified TTR to C57Black6, the expression of TTR mRNA decreased from 6 to 24 h post injection, and gradually increased up to 48 h post injection. After injecting 400 mg of normal TTR in each of 3 FAP patients, total plasma TTR levels were elevated and variant TTR levels decreased significantly from 24 to 48 h. These results suggested that down regulation of the harmful protein by replacement of its normal form of the protein occurred by this method. This phenomenon should be applied as the basis for one of the useful methods for decreasing the harmful proteins in the circulation.

Adult↗
PubMed1997

Role of nitric oxide in the cerebellar degeneration during methylmercury intoxication.

To investigate the role of nitric oxide in the cerebellar degeneration during methylmercury intoxication, interaction of the change in nitric oxide synthase activity and degeneration of the granular layer neurons was examined in rats after methylmercury administration. Both reduced nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase and anti-nitric oxide synthase antibody staining, and measurement of glutamate, and nitrite and nitrate levels in the cerebrospinal fluid were performed after oral administration of 5 mg/kg of methylmercury for 12 days. Nitric oxide synthase activity in the cerebellum was also assayed by monitoring the conversion of arginine to citrulline. Methylmercury levels in the blood and the cerebellum gradually increased up to day 13 after the initial methylmercury administration, and neurological disturbances, such as hindleg crossing and abnormal gait, were observed from day 17 after administration. Although a significant decrease in the number of granular layer neurons was recognized at day 84, no such decrease either in NADPH-diaphorase or anti-nitric oxide synthase antibody positive neurons was seen. Glutamate levels in the cerebrospinal fluid transiently increased at day 9 and finally decreased at day 84. Also a transient increase in both nitrite and nitrate levels in the cerebrospinal fluid and nitric oxide synthase activity in the cerebellum was seen prior to the start of degeneration of the granular layer neurons. These results suggest that nitric oxide may play an important role in the degeneration process of the granular layer neurons during methylmercury intoxication.

Animals↗
PubMed1997

Failure of the nitric oxide synthase inhibitor to stimulate duodenal bicarbonate secretion in streptozotocin-diabetic rats.

We examined the HCO(3)- stimulatory effects of L-NAME (N(G)-nitro-L-arginine methyl ester) in the proximal duodenum of streptozotocin (STZ)-induced diabetic rats and compared with those of 16,16-dimethyl prostaglandin E2 (dmPGE2) and vagal electrical stimulation. Male SD rats were given STZ (70 mg/kg) i.p., and the experiments were done using 1 approximately 6 week STZ-diabetic rats with blood glucose levels of >300 mg/dl. Under urethane anesthesia the HCO(3)- secretion was measured in the proximal duodenal loop using a pH-stat method and by adding 10 mM HCl. Hyperglycemic conditions appeared 1 week after STZ treatment and remained during 6 week-test period. The duodenal HCO(3)- secretory response to L-NAME was significantly decreased in STZ-diabetic rats; the degree of reduction was dependent on the duration of diabetes, and the stimulatory effect disappeared completely in rats after 5 approximately 6 weeks of diabetes. Intravenous administration of L-NAME markedly increased arterial blood pressure with significant decrease in heart rate in normal rats, whereas in STZ-diabetic rats this agent caused only pressor response without any effect on heart rate. STZ-diabetic rats also secreted significantly less amount of HCO(3)- from the duodenum in response to dmPGE2 and vagal electrical stimulation after 5 approximately 6 weeks of diabetes. These all changes observed in STZ-diabetic rats were significantly reversed by daily injection of insulin. These results suggest that 1) L-NAME failed to stimulate duodenal HCO(3)- secretion in STZ-diabetic rats, and 2) impairment of the duodenal HCO(3)- secretory ability in STZ-diabetic conditions is due to both vagal-dependent neuronal dysfunction and decreased sensitivity of the secreting cell.

16,16-Dimethylprostaglandin E2↗
PubMed1997

Alterations in duodenal bicarbonate secretion and mucosal susceptibility to acid in diabetic rats.

BACKGROUND & AIMS: The gastroduodenal mucosal susceptibility to ulcerogenic stimuli increases in diabetic conditions, but the mechanism is unknown. The aim of this study was to investigate alterations in duodenal HCO3- secretory response in diabetic animals. METHODS: The experiments were performed in rats treated with streptozotocin (70 mg/kg intraperitoneally) after 1-6 weeks of diabetes, when blood glucose levels were > 300 mg/dL. HCO3 secretion was measured in the proximal duodenal loop of rats that were under urethane anesthesia using a pH-stat method. RESULTS: The duodenal HCO3 secretion induced by mucosal acidification was decreased in streptozotocin-treated rats depending on the duration of diabetes. The HCO3 secretion was also decreased in response to 16,16-dimethyl prostaglandin E2, vasoactive intestinal polypeptide, or vagal electrical stimulation. Acid load in the duodenum produced extensive damage in 5-6-week diabetic rats, although the same treatment caused only slight damage in the normal rat duodenum. Such alterations in the duodenal HCO3 secretory and ulcerogenic responses in diabetic rats were partially restored by daily injection of insulin. CONCLUSIONS: The results suggest that streptozotocin-diabetic conditions impair the duodenal HCO3- secretion in rats, possibly as a result of decreased sensitivity of the epithelial cell and dysfunction of neuronal pathway, thereby increasing the mucosal susceptibility to acid injury in the duodenum.

Animals↗
PubMed1996

Autonomic dysfunction and anemia in neurologic disorders.

The effect of autonomic dysfunctions on anemia in various neurological disorders, such as familial amyloidotic polyneuropathy (FAP) Type I, pandysautonomia, and Shy-Drager syndrome was examined. As a control, hemograms of patients with amyotrophic lateral sclerosis (ALS), which is known to be free from autonomic dysfunction, was compared with patients with the above neurological disorders. FAP and pandysautonomia patients showed significant anemia comparable with the severity of the autonomic dysfunctions. Shy-Drager patients exhibited mild anemia. However, in ALS patients, no such anemia was recognized at all even in the end stage of this disease. In pandysautonomia patients, hypoplastic bone marrow was recognized, which was quite consistent with the data previously reported in FAP patients. Human recombinant erythropoietin improved orthostatic hypotension as well as anemia in 4 FAP patients. These results suggest that autonomic dysfunction may be deeply connected with erythropoiesis.

Adult↗