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Biomedical subjects

K Tomoda

Publications and source records attributed to K Tomoda.

At least 91 records · Page 5Linked to original sources
PubMed1993

Effects of acetazolamide on acid-base balance in the endolymphatic sac of the guinea pig.

The effects of acetazolamide, a carbonic anhydrase inhibitor, on acid-base parameters in the endolymphatic sac of the guinea pig were investigated using ion-selective microelectrodes. Bicarbonate concentration was reduced and pH shifted to being acidic immediately after administration of acetazolamide. Chloride concentration in the endolymphatic sac increased after carbonic anhydrase inhibition. These findings provide evidence of an active function of carbonic anhydrase in the endolymphatic sac and suggest that carbonic anhydrase activity is involved in the formation of endolymphatic sac fluid.

Acetazolamide↗
PubMed1993

Regional blood flow volume in the eustachian tube.

Measurements of regional blood flow around the pharyngeal orifice of the Eustachian tube were carried out after topical administration of various inflammatory mediators in 14 mongrel dogs by the hydrogen clearance method. Histamine and platelet-activating factor (PAF) resulted in a significant alteration of blood flow volume. Histamine was found to induce a dose-response related increase, whereas blood flow volume tended to decrease in each concentration range in the series of PAF administration. There was no significant difference in blood flow between topical application of leukotriene C4 and leukotriene D4. It is likely that in upper respiratory tract inflammation, such as in otitis media and in nasal allergy, activated histamine and PAF affect the microcirculation of the tubal orifice. These results suggest that disturbance of the microcirculatory system in the Eustachian tube mucosa could be involved in the pathogenesis of chronic otitis media with effusion.

Animals↗
PubMed1993

The usefulness of partial parotidectomy for benign parotid gland tumors. A retrospective study of 306 cases.

This retrospective study concerns benign parotid gland tumors in 306 Japanese patients who were treated by partial parotidectomy with preservation of the facial nerve. There were no recurrences in 112 with a pleomorphic adenoma in over a 5-year follow-up. Facial weakness and temporal paresis occurred in 18% of 232 patients and Frey's syndrome in 18% of 93 with longer than a 3-year follow-up. In comparison with reported results of lateral or superficial parotidectomy, partial parotidectomy with preservation of the facial nerve seems preferable for treatment of patients with a benign parotid gland tumor.

Facial Nerve Injuries↗
PubMed1993

Thyroid follicle transplantation by percutaneous injection.

We previously reported on the isolation of thyroid follicles from thyroid tissue and their acceptance after allogeneic transplantation under the renal capsule with laparotomy in mice. In the present study, we introduced a new method of autologous transplantation of thyroid follicles accepted in the hosts after percutaneous injection into the spleen or into fat tissue in the peritoneal cavity without laparotomy in rats. This method of thyroid transplantation by a single injection, which induces little stress in the host, is applicable to autologous and allogeneic transplantations and may release patients from the burden of daily life-long administration of thyroxine.

Animals↗
PubMed1993

Sympathetic nerve disturbance and fine structure of adrenergic nerve terminals in nasal mucosa after experimentally-induced nasal hypersensitivity.

Electron microscopic observations were used to study the relation between the adrenergic nerve terminal and the effector cell in the nasal mucosa of toluene diisocyanate-sensitized and non-sensitized guinea pigs. Adrenergic nerve terminals were abundantly distributed in the adventitia of arterioles, however, no synapse formation was observed in smooth muscle cells of the mesothelium, i.e., effector cells. Adrenergic nerve terminals were observed separated from smooth muscle cells of the mesothelium of the arteriole by distances of 1000 A-3000 A. Neurotransmission by the sympathetic nerve in the nasal mucosa is assumed to be by diffusion of norepinephrine (NE) or by diffusive synaptic conduction. The mechanism of sympathetic hypofunction in the nasal mucosa in nasal hypersensitivity is assumed to be as follows: Released histamine directly stimulates H-1 receptors at the sympathetic nerve terminal, leading to the release of NE. Once released, NE is not readily reabsorbed, and is gradually depleted in the sympathetic nerve terminal, leading to hypofunction of the sympathetic nerve.

Adrenergic Fibers↗
PubMed1993

[Clinical features of primary and secondary atypical mycobacteriosis].

A clinical investigation was carried out in 39 patients with atypical mycobacteriosis (AM). The patients at our hospital diagnosed as having AM during an 11-year period from 1981 to 1991 were reviewed in this study. The incidence of AM among all of mycobacterial infections has been increasing since 1988. The atypical mycobacteria detected included M. avium complex (MAC) in 79%, M. kansasii in 26%, and other organisms in 5%. Patients who had primary infection without underlying respiratory disease were compared with those who had secondary infection. In secondary infection, MAC was detected in the sputum of a high percentage of patients and was positive for more than 6 months despite therapy. Gamma globulin levels were also increased in patients with secondary infection. Cell mediated immunity was examined by the DNCB reaction and the detection of CD4- and CD8- positive T lymphocytes. The DNCB skin reaction was positive in 6 out of 26 patients with secondary infection. The percentage of CD8- positive T lymphocytes was higher in patients with secondary disease. Fischer's ratio (indicating the balance of plasma amino acids) was also examined as an index of the nutritional status. It was significantly lower in secondary infection compared with primary infection. Moreover, secondary infection was associated with a lower positive rate for the DNCB skin reaction and a lower Fischer's ratio when compared with pulmonary tuberculosis. Thus impairment of cell-mediated immunity, malnutrition, and a poor prognosis were significantly more common in secondary infection compared with primary infection.

Adolescent↗
PubMed1993

[An autopsy case of atypical mycobacteriosis accompanied with chest wall deformity].

An autopsy case of 63-year old male of atypical mycobacteriosis with severe scoliosis was reported. He was diagnosed as atypical mycobacteriosis in 1981 and controlled by antimycobacterial treatment. But since 1989, dyspnea and sputum have been increasing, new abnormal shadow in company with progression of curvature of the scoliosis was revealed on the chest roentgenogram. In spite of various treatments for mycobacteriosis, he died of respiratory failure. The aggravation of this mycobacteriosis brought on advancement of malnutrition and impairment of cell mediated immunity. Findings of autopsy showed the remarkable chest wall deformity and tuberculous change of the lung parenchyma. In this case, chest deformity was thought as the major risk factor of onset of mycobacterial mycobacteriosis.

Humans↗
PubMed1993

Detection of viable tumor cells in hepatocellular carcinoma following transcatheter arterial chemoembolization with iodized oil. Pathologic correlation with dynamic turbo-FLASH MR imaging with Gd-DTPA.

To evaluate the effect of transcatheter arterial chemoembolization (TACE) with iodized oil for hepatocellular carcinoma (HCC), dynamic turbo-fast low angle shot (turbo-FLASH) (TR/TE/flip angle/TI, 8.5/4.6/10/200) MR imaging with gadopentetate dimeglumine was performed in 10 patients with HCC after TACE with iodized oil and before partial hepatectomy. Immediately after 0.05 mmol/kg b.w. of gadopentetate dimeglumine was administered intravenously, 10 images were obtained in the first 20 s (early phase). Then, one image every 30 s from 1 to 3 min (late phase), and images at 5 min and 7 min (delayed phase) were obtained serially. In the early phase, HCC showed no enhancement in 5 patients, partial hyperintense enhancement in 4, and total hyperintense enhancement in one. Viable regions of the tumor, evaluated at histopathology, showed hyperintense enhancement relative to the surrounding liver parenchyma in the early phase, while necrotic regions showed no enhancement. Both viable and necrotic regions showed lower signal intensities than the surrounding liver parenchyma in both late and delayed phases. By using dynamic turbo-FLASH MR imaging, we were able to accurately evaluate the effect of TACE with iodized oil for HCC in 8 of the 10 patients. In 2 patients, in whom small viable cells were seen in the HCC, viable regions could not be detected with our technique. It is concluded that turbo-FLASH dynamic MR imaging was useful for evaluating the effect of TACE for HCC.

Aged↗
PubMed1992

[MR imaging evaluation of plica synoviallis mediopatellaris of the knee joint].

To evaluate the diagnostic ability of MR imaging for plica synoviallis mediopatellaris (PSM), we retrospectively reviewed the MR imaging findings of patellofemoral space in 20 knee joints of 11 patients. In all 20 knee joints, arthroscopy and MR imaging were available. MR imaging was performed with a 1.5 Tesla Magnetom (Siemens) using a round surface coil. Pulse sequences were SE (TR 600 ms/TE 26 ms), SE (TR 200 ms/TE 26, 70 ms) and FLASH (TR 450 ms/TE 15 ms/FA 90 degrees). In six of the 20 knees with PSM proved by arthroscopy, a low intensity band was shown above the medial condyle of the femur on both T1- and T2-weighted MR images, and on FLASH images this band was shown as intermediate intensity. In the other 14 knees with no PSM observed by arthroscopy, the low intensity band was not shown on MR imaging. In all 20 knees, a similar low intensity band was shown about 1 cm cranial to the medial condyle of the femur. This should not be diagnosed as PSM. The low intensity band seen on T1- and T2-weighted MR images and its anatomical relation to the medial condyle are important in diagnosing PSM.

Adolescent↗
PubMed1992

[Dynamic 3DFT FISP MR imaging of hepatocellular carcinoma].

Dynamic 3 dimensional Fourier transformation (3DFT) FISP MR imaging was performed in 5 patients with hepatocellular carcinoma before partial hepatectomy. Immediately after 0.1 mmol/kg of Gd-DTPA was administered intravenously, 3DFT FISP images (TR/TE/flip angle/slice thickness, 20 msec/8 msec/30 degrees/2-4 mm) were obtained every 30 seconds until 150 sec. We correlated dynamic MR images of the 5 patients with gross and microscopic findings. Some regions in the tumor corresponding to viable cells showed high intensity enhancement and other regions corresponding to necrotic regions showed no enhancement on the early phase images. We concluded that dynamic 3DFT FISP MR imaging which had good spatial resolution was useful in evaluating the vascularity of the tumor.

Aged↗
PubMed1992

[Differentiation between hepatoma and hemangioma by inversion recovery snapshot FLASH MR imaging with variable TIs].

To differentiate hepatoma from hemangioma, MR studies were performed for 18 patients with 21 untreated liver tumors (hepatoma 10, hemangioma 11). We obtained inversion recovery snapshot FLASH images of liver tumors with variable TIs (50, 100, 150, 200, 250, 300, 400, and 500 msec). 8 hemangiomas showed higher intensity than liver parenchyma on the images at 150 msec and less of TI, and lower intensity at 200 msec or more TI. In 7, signal intensity of hepatoma became low at 150 msec or less of TI or remained high with prolonged TI. Inversion recovery snapshot FLASH imaging with variable TIs will be useful for differentiating between hepatoma and hemangioma.

Adult↗
PubMed1992

Small-angle x-ray scattering study of metal ion-induced conformational changes in Serratia protease.

Metal ion-induced conformational changes in Serratia protease which contains one zinc ion per molecule were investigated by the small-angle x-ray scattering method. The molecule is an elongated ellipsoid of approximately 110 x 40 x 40 A with a large cleft in its central region. Comparisons of the native (zinc-enzyme) with the zinc-free (apoenzyme) enzyme and with the zinc-replated metalloenzyme show small but significant differences in their radii of gyration, maximum particle dimensions, and intraparticle pair-distance distributions. The radius of gyration and maximum particle dimension of the native enzyme are almost the same as those of the cobalt-enzyme but are shorter and longer, respectively, than those of the apo- and cadmium-enzymes. Simulation analysis based on the intraparticle pair-distribution function showed that these modified enzymes are comparable with the native enzyme in overall structure, and, except for the cobalt-enzyme, differ in cleft size. The residual enzymatic activity of the cobalt-enzyme is the same as that of the native enzyme, but the apo- and cadmium-enzymes have considerably less activity. The size of the cleft therefore is strictly controlled to ensure optimal enzyme activity, and the position and coordination behavior of the zinc ion in the cleft appears to be essential both for biological functioning and for the maintenance of the gross tertiary structure.

Metalloendopeptidases↗
PubMed1992

Flumazenil does not antagonize halothane, thiamylal or propofol anaesthesia in rats.

We have studied the effects of flumazenil on sleep time and EEG in rats anaesthetized with 1.5% halothane, propofol 20 mg kg-1, thiamylal 30 mg kg-1, or combinations of diazepam 5 mg kg-1 and anaesthetic agents. We also studied the effects of flumazenil 0.3, 3 and 30 mg kg-1 on behaviour and EEG. Flumazenil 0.3 and 3 mg kg-1 alone had no effect on behaviour or EEG, but flumazenil 30 mg kg-1 had depressive effects similar to those of diazepam on behaviour and EEG. Flumazenil 0.3, 3 and 30 mg kg-1 i.v., antagonized the effects of diazepam 10 mg kg-1 i.v. on behaviour and EEG. Flumazenil had no antagonistic effect on sleep time induced by anaesthetic agents, but flumazenil 30 mg kg-1 potentiated propofol-induced anaesthesia. Flumazenil did not affect anaesthesia-induced EEG changes. Diazepam 5 mg kg-1 potentiated anaesthesia. Flumazenil antagonism of diazepam potentiation varied with anaesthetic agent: flumazenil 0.3 mg kg-1 antagonized diazepam action in halothane anaesthesia, but 30 mg kg-1 was required in propofol anaesthesia; this large dose was insufficient in thiamylal anaesthesia.

Anesthesia, Inhalation↗
PubMed1992

Alterations of charge barrier in the inner ear following immune reactions.

We investigated electron microscopically the changes of anionic sites of a charge barrier in the capillary basement membrane of the stria vascularis and endolymphatic sac following inner ear immune reactions. Hartley guinea pigs were immunized with bovine type II collagen, keyhole limpet hemocyanin, or horseradish peroxidase, with boosted and challenged antigens through the stylomastoid foramen. Animals were killed painlessly from several days up to 56 days after the antigen challenge. Polyethylenimine was used as a cationic tracer in order to observe the localization of anionic sites of the charge. In the animals immunized with bovine type II collagen or horseradish peroxidase, a significant decrease of anionic charge in the stria and the sac was found in the early stage of immunization. However, the keyhold limpet hemocyanin immunization group did not show any remarkable changes in the charge because of its lesser transfer into the inner ear due to of its high molecular weight and negative surface charge. A decrease of the charge under immunologic conditions may induce a hyperpermeability of vessels and a malabsorption of endolymph, and thus may cause endolymphatic hydrops.

Animals↗
PubMed1992

MR diagnosis of meniscal tears of the knee: value of axial three-dimensional Fourier transformation GRASS images.

Axial MR images of 40 knees in 37 patients with clinically suspected meniscal tears were obtained by using a three-dimensional (3-D) Fourier transform, gradient-refocused acquisition in the steady state (GRASS) pulse sequence. All knees also were examined in both coronal and sagittal planes with a two-dimensional (2-D) Fourier transform, spin-echo pulse sequence for T1-weighted images and a multiplanar GRASS pulse sequence for T2*-weighted images (conventional 2-D pulse sequences). Arthroscopic confirmation was available in all cases and was used as the gold standard. In these 40 knees, 32 of 33 meniscal tears and 45 of 47 normal menisci were correctly identified with axial 3-D imaging, yielding a sensitivity of 97% and specificity of 96%. Conversely, the sensitivity was 82% and the specificity was 100% for the 2-D technique in the diagnosis of meniscal tears. A combination of both techniques yielded 100% sensitivity, 100% specificity, and 100% accuracy in the evaluation of the menisci. Seven discrepancies between the findings of the two techniques were found in the evaluation of 33 arthroscopically proved torn menisci; six of the seven represented false-negative 2-D images and one was a false-negative axial 3-D image. Of 47 normal menisci, only two false-positives occurred with axial 3-D imaging and none with 2-D imaging. Despite the lack of a statistically significant difference, these preliminary findings suggest that the sensitivity in the diagnosis of meniscal tears can be improved by adding thin-sliced axial images with the 3-D GRASS pulse sequence to conventional 2-D imaging.

Adolescent↗
PubMed1992

Effects of various inflammatory mediators on eustachian tube patency.

The effects of several inflammatory mediators on the patency of the Eustachian tube were evaluated in 15 mongrel dogs. Histamine, leukotriene C4(LTC4) and D4(LTD4), and platelet activating factor (PAF) were perfused through the Eustachian tube of anesthetized dogs at concentrations detected in human middle ear effusion of patients with otitis media. The patency of the Eustachian tube was then evaluated by perfusion pressure and opening pressure. Histamine at concentrations of more than 10(-5) M caused increased tubal resistance and opening pressure rapidly. LTC4 and LTD4 caused a rapid increase of tubal resistance and opening pressure at far lower concentrations, i.e. 10(-12) M. Doses of PAF over 10(-9) M may cause an increase in the opening pressure. These results indicate that various inflammatory mediators are capable of affecting the Eustachian tube function.

Animals↗
PubMed1992

Experimental interruption of the endolymphatic duct and its effect on the DC potential in the endolymphatic sac.

The endolymphatic sac (ES) of the guinea pig was isolated from the remainder of the inner ear by means of surgical interruption of the endolymphatic duct (ED). The DC potential in the ES lumen and the morphology of the ES were studied using glass micro-electrodes and a light microscope at various time intervals after the interruption of ED. The DC potential did not significantly change 1 h postoperatively, compared to findings in the non-operated ear, but a significant decrease of the DC potential was observed after 1, 3 and 7 days postoperatively. A histologically-stainable substance in the ES lumen was enhanced on the operated side. The isolated ES shows a disturbance of mechanism(s) maintaining the DC potential and there is a secretion of a stainable substance into its lumen.

Animals↗