Search PubMed⌕ Search

Biomedical subjects

T Tabata

Publications and source records attributed to T Tabata.

At least 307 records · Page 17Linked to original sources
PubMed1986

Responses of somatosensory cortical neurones to tooth pressure and their modulation by transient mouth opening in the cat.

One hundred and thirty two cortical neurones sensitive to mechanical tooth stimulation were detected from the caudal part of the coronal gyrus of the cat. They responded to transient mechanical stimulation of the tooth (TMTst) with initial burst discharges (latency; 14.9 +/- 8.7 ms) and sequential suppression of spontaneous discharges (duration; 218 +/- 142 ms). They also fired strongly at the onset and removal of sustained mechanical stimulation of the tooth (SMTst) with both on and off responses, but the responses for the duration of stimulation were indistinguishable from the spontaneous discharge level. Conditioning stimulation by transient mouth opening (TMOst) inhibited the on and off responses elicited by tooth pressure in 13 (56.5 per cent) of the 23 cortical neurones and in 16 (88.9 per cent) of the 18 neurones tested, respectively. On reversing the conditioning-test sequence, the response elicited by TMOst was inhibited by the onset and removal of SMTst in 12 (52.2 per cent) of the 23 neurones and in 8 (44.4 per cent) of the 18 neurones tested, respectively. The inhibitory period ranged from 50 to 250 ms.

Animals↗
PubMed1986

Response properties of periodontal mechanosensitive fibers in the superior dental nerve of the cat.

Periodontal mechanosensitive units were detected as single nerve fibers from the anterior branches of five cats, and their receptive fields and optimal stimulus directions were examined. Of 801 units detected, 759 units (95%) responded to movement of only one tooth (single-tooth unit), and 42 units (5%) responded to movement of two or three teeth (multitooth unit). Eighty percent of the single-tooth units were of the sustained type which discharged during more than 1 s to a long-lasting pressure applied to the tooth, and 20% were of the transient type which adapted in less than 1 s to the pressure. The majority (93%) of the sustained type exhibited directional selectivity to stimulation, but only 35% of the transient type showed it. More than half of the single-tooth units had their receptive fields in the canine tooth, stimulation of which produced the largest mass discharge in the nerve bundle. The optimal stimulus direction for many single-tooth units was the same as that for the mass discharge in the nerve bundle. The receptive fields of the multitooth units were observed mainly in the incisor teeth adjacent to each other.

Action Potentials↗
PubMed1986

Acute renal failure in McArdle's disease.

This is a report of a case of acute renal failure associated with McArdle's disease. A 45-year-old man had acute renal failure that required dialysis. His case was subsequently diagnosed as rhabdomyolysis secondary to McArdle's disease, a primary myopathy due to myophosphorylase deficiency. History-taking revealed nothing suspected to be responsible for precipitating the renal failure.

Acute Kidney Injury↗
PubMed1986

The effect of 1 alpha-hydroxyvitamin D3 on cell-mediated immunity in hemodialyzed patients.

The immunoregulatory effect of 1 alpha-hydroxyvitamin D3 (1 alpha OHD3), a precursor form of active vitamin D3, was examined in hemodialyzed patients. Four weeks of oral administration of 0.5 micrograms/day 1 alpha OHD3 markedly enhanced the lymphoproliferative responses to mitogens without influencing lymphocyte counts or the ratios of lymphocyte subpopulations. In fact, these responses were nearly normal after treatment. These results suggest that deficiency of 1,25-dihydroxyvitamin D3 may play a role in the impairment of cellular immunity in hemodialyzed patients, and that administration of 1 alpha OHD3 may have therapeutic immunological benefit.

Adult↗
PubMed1985

A diurnal variation of hepatic acid cholesteryl ester hydrolase activity in the rat.

The diurnal variation in lysosomal acid cholesteryl ester hydrolase (Acid CEH), (EC 3.1.1.13) has been examined in fed, fasted and adrenalectomized rats. The Acid CEH activity of normal rat liver exhibits a diurnal rhythm with maxima at 06.00 hours and minima at 18.00 hours, but such a rhythm was not observed in spleen and brain. This rhythm was abolished after fasting for two days, and the resulting Acid CEH activity remained constant at the minimum level. However, adrenalectomy did not abolish the diurnal rhythm. These results indicate that the Acid CEH activity varies according to a diurnal rhythm with maxima and minima separated by approximately 12 hr. Further, it is evident that the appearance of this rhythm is dependent upon dietary, but not adrenal hormone influence.

Adrenalectomy↗
PubMed1985

Response fields of the periodontal mechanosensitive units in the superior alveolar nerve of the cat.

Response properties of periodontal mechanoreceptor primary afferent fibers recorded from the superior alveolar nerve were studied in the cat. The left maxillary canine tooth was stimulated manually in 8 directions and/or in 24 directions in the horizontal plane by a specially designed stimulator. The responses of 328 slowly adapting units observed were affected by the direction of stimulus. These units were classified into three groups according to the shape of the response field: a broad type (more than 180 degrees), a medium type (90 degrees to 180 degrees), and a narrow type (less than 90 degrees). The groups contained 27 units (8.2%), 284 units (86.6%), and 17 units (5.2%), respectively, and the remaining 10 units (10.0%) were unclassified. The shape of each response field was little changed by changes in the stimulus intensity. Every response field investigated showed a unimodal distribution. These results were different from those of Mei et al. (1975) who reported that the response fields of units recorded from a Gasserian ganglion had generally consisted of two parts.

Animals↗
PubMed1985

Quantitative determination of bacterial endotoxin in middle ear effusions by chromogenic substrate method.

It is known that bacterial endotoxin on the outer surface of most gram-negative bacteria (GNB) is not only biologically active material, but also the modulator of the immune response. The earlier experiment documented that the endotoxin of killed Haemophilus influenzae was responsible for induction of chronic otitis media with effusion (OME). Recent study by DeMaria et al. determined the endotoxin of human middle ear effusion (MEE) by means of limulus amebocyte lysate assay. It was concluded the endotoxin was present in a high percentage of the effusion in human tympanic cavities. The present study was undertaken to quantitatively determine the endotoxin in human MEE by use of chromogenic substrate technique which is more sensitive and accurate than limulus assay. Sixty samples of mucoid and serous effusion were subjected to chromogenic substrate method. It was revealed that the mucoid effusion showed a significantly high level of endotoxin at 282 pg/ml in average, though the serous effusion contained only 35.9 pg/ml. It is assumed that the bacterial endotoxin may greatly contribute to the pathogenesis of otitis media with mucoid effusion.

Adolescent↗
PubMed1985

Experimental studies on immunogenesis of otitis media with effusion.

In order to investigate otitis media with effusion from the systemic perspective, we have studied histological reactions of the mucous membrane in the both middle ears in the sensitized animals. Guinea pigs were initially immunized by injection of BSA conjugated with alum (BSA-alum) into unilateral tympanic cavity. The second challenge of BSA-alum was performed on the seventh day after primary sensitization under an appropriate schedule. The guinea pigs were sacrificed for histological examination at 3 days after the second administration. Histological changes of the middle ear mucosa in the sensitized ear were characterized by hypertrophy of mucosa with fibrosis. Numerous mononuclear cells also existed. In non-sensitized ear (opposite side), the changes were edema of the mucosa showing mild proliferation of fibroblast and vasodilation. Mainly mononuclear cells were scattered. It was noted that these reactions were weaker than those of the sensitized ear.

Animals↗
PubMed1985

Transient glucose intolerance during attacks of thyrotoxic periodic paralysis.

In a 19-year-old Japanese male (case 1) with thyrotoxic periodic paralysis (TPP), an increase of plasma glucose concentration together with abnormally high levels of serum immunoreactive insulin (IRI) was observed preceding a spontaneous attack of paralysis. Therefore, the plasma glucose, glucagon, epinephrine, norepinephrine, serum IRI, growth hormone and cortisol levels, and the erythrocyte insulin receptors were measured in case 1 and a 40-year-old Japanese male (case 2) with TPP during attacks of paralysis induced by prolonged glucose loading. In case 1, the serum IRI concentration was elevated to the extraordinarily high level of 655.0 microU/ml at the beginning of paralysis, and at that time, the plasma glucose concentration was 147 mg/dl. However, when paralysis was not induced by a similar glucose loading during methimazole treatment, the serum IRI and plasma glucose levels at the corresponding time after glucose loading were 20.9 microU/ml and 87 mg/dl, respectively. Furthermore, the affinity of the erythrocyte insulin receptors was decreased during the attack. In case 2, plasma glucose and serum IRI concentrations were increased in accordance with the initiation of paralysis although the blood levels of hormones counteracting insulin were not significantly changed. These findings suggest that there is something interacting with the normal action of the insulin in the early phase of paralysis.

Adult↗
PubMed1984

Characterization of a cytosolic protein inhibiting lysosomal acid cholesteryl ester hydrolase.

An inhibitor of lysosomal acid cholesteryl ester hydrolase (Acid CEH), (EC 3.1.1.13) was found in the cytosolic fraction of rat liver and various other tissues. The extent of the inhibitory effect was dependent on the concentration of the cytosolic protein. The Acid CEH inhibitor was heat-labile, non-dialyzable, and its inhibitory activity significantly decreased by trypsin or chymotrypsin digestion, but not by lipase digestion. The inhibitor had no effect on the activity of cathepsin D, beta-glucuronidase and acid phosphatase, which are other enzymes found in lysosomes. The present findings suggest that the inhibitor may be involved in the regulation of the hydrolysis of cholesteryl esters in lipoproteins that have been transferred into the liver.

Animals↗
PubMed1984

Maturational impairment of thymic lymphocytes in streptozotocin-induced diabetes in rats.

Streptozotocin (STZ)-induced diabetes in rats was associated with marked decreases in thymus weight and the number of thymic lymphocytes. Histologically, the cortical lymphocytes which were present near the cortico-medullary junction in the thymus seemed to be reduced selectively in the STZ-induced diabetes. Rosette-forming cells, which bind to guinea pig erythrocytes in the presence of fetal calf serum, were also significantly decreased. Insulin treatment allayed these intrathymic changes. Preincubation of thymic lymphocytes from diabetic rats with thymosin fraction 5 significantly enhanced the percentage of rosette-forming cells to near the control level. These results suggest that a maturational impairment of thymus cortical lymphocytes may be caused in STZ-induced diabetes with hypoinsulinemia and it may be intimately related to reductions in thymus weight and the number of thymic lymphocytes.

Animals↗
PubMed1984

Molecular cloning and nucleotide sequence of a variant wheat histone H4 gene.

To determine whether there is structural variation among histone H4 genes in wheat, one (TH091) of the H4 genes that had been cloned from a wheat genomic DNA library was sequenced and compared with another H4 gene (TH011) which we had described previously [Tabata et al., Nucl. Acids Res. 11 (1983) 5865-5865]. Nucleotide sequence analysis revealed that there are 17 nucleotide replacements in the protein-coding region of two H4 genes, causing only one amino acid substitution: a glycine at position 4 (from the N terminus) in TH011 was replaced by an aspartic acid in TH091. S1 mapping, using total nuclear RNA from germinated seeds, indicated that the H4 gene was transcribed in vivo.

Amino Acid Sequence↗
PubMed1984

Transcription of cloned actin genes of Dictyostelium discoideum in the cell-free system.

Truncated templates of a cloned actin gene (actin 5) of Dictyostelium discoideum were transcribed in a HeLa cell extract from a position indistinguishable from the in vivo initiation site. The efficiency of this accurate transcription, however, was very low compared with that of the adenovirus 2 major late gene in the same system. Transcription of the actin 6 and 8 genes, of which the 5'-flanking regions differ in their base sequences from the corresponding region of the actin 5 gene, was not good in either fidelity or efficiency. When the partially purified RNA polymerase II of D. discoideum was used instead of the HeLa cell extract, no accurate transcription of the actin 5 gene occurred. However, simultaneous addition of RNA polymerase II and HeLa cell extract into the cell-free system caused a shift of the in vitro initiation point of transcription of the actin 5 gene to a position about 20 nucleotides downstream from the presumed in vivo initiation site. The reason for the shift remains unknown, but it is supposed that some factor(s) other than RNA polymerase II are involved in the accurate initiation of transcription and the maintenance of transcription efficiency of the actin genes.

Actins↗