Biomedical subjects
Publications and source records attributed to N Matsubara.
A 41 year-old male was admitted to our hospital, because a suspicious shadow in the right lower lung field was on X-ray. Investigations could not confirm cancer but were highly suggestive of it. Finally, right lower lobectomy was performed, and the histopathological finding of the tumor resected were a mixture of epithelial components in myxomatous tissue, so a diagnosis of pleomorphic adenoma of the lung was made.
The long-axis (L-A) tomograms of the heart in thallium-201 SPECT have been conventionally reconstructed as those parallel to the midventricular vertical or horizontal L-A plane. We developed a new algorithm for reconstructing the rotated L-A tomograms around the L-A to longitudinally observe thallium-201 myocardial distribution and to provide an optimal view of the cardiac apex. After determining the orientation of the L-A and reconstructing the short-axis (S-A) tomograms using standard techniques, the coordinates of the S-A planes were transformed to the polar coordinates whose origin is located at the position of the L-A in each plane. Then, "radial L-A tomograms", i.e. midventricular L-A planes oriented at the angle of every 6 degrees to the midventricular horizontal L-A plane, were reconstructed. Also, we developed a new technique for analyzing thallium-201 distribution of the L-A tomograms. For the basal 2/3 regions, two profiles which consist of the pixels with maximum count on the upper and lower myocardial portions of the lines (spaced at 1 pitch) vertically to the L-A were computed. For the remaining apical 1/3 regions, the semi-circumferential maximum-count profile from the values of 30 radii spaced at 6 degrees interval were computed. Based on these profiles, a 2D polar representation was then generated. From the study using a cardiac phantom with an apical small infarction, the usefulness of this new tomographic method for the detection of apical myocardial ischemia was demonstrated. The application to the exercise/redistribution studies in patients with effort angina indicated that radial long-axis tomography provides precise information about the longitudinal extent of perfusion defects, particularly in the apical regions.
To estimate regional left ventricular (LV) diastolic filling patterns in hypertrophic cardiomyopathy (HCM), a computer-assisted method by applying "sector analysis" to ECG forward and reverse gated radionuclide ventriculography was developed. Fourteen patients with HCM (four with localized septal hypertrophy, seven with apical hypertrophy and three with septal and apical hypertrophy according to echocardiography) were observed at rest. After establishing serial 20 msec imaged frames, the LV region of interest was subdivided into eight sectors radiating from the geometric center. A time-activity curve was generated for each sector and was fitted by third-order harmonics of the Fourier series. From each fitted curve, the regional peak filling rate (rPFR) and the time of rPFR (rTPFR) in the forward gating method and regional atrial contribution to filling (rAC/FV) in the reverse gating method were calculated. The coefficient of variance of rTPFR was used as an index of LV diastolic asynchrony. In HCM, a prominent delay of rTPFR was observed in the hypertrophied regions. The coefficient of variance of rTPFR correlated inversely with global LVPFR (r = -0.62, p less than 0.05), indicating that diastolic asynchrony is one of the determinants of the LV early filling rate. Regional AC/FV was augmented in the hypertrophied regions, indicating the important role of atrial systolic LV filling for slowed early filling. Thus, this new method provides valuable information concerning regional diastolic LV wall mechanics in HCM.
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During a two-year period, from August, 1983 to July, 1985, 144 gastric cancer patients have been treated at the National Tohsei Hospital. Among them, 57 patients were determined as having an early gastric carcinoma. Four patients (7.0%) of this number were found to have a multicentric type, 3 manifesting a double II c type, and 1 patient having both a I type and II a type. Pathologically these two types carcinomas were found in only one patient, in a so-called kissing position.
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To clarify the mechanism of inspiratory reduction of left ventricular (LV) stroke volume (SV) during spontaneous respiration, we measured right and left ventricular volume changes from expiration to inspiration using radionuclide ventriculography with respiratory gating technique. In this method, scintigraphic data were acquired in a list mode with ECG R wave triggers and respiratory volume curve derived from respiratory flowmeter. Cardiac cycles occurring during the second halves of inspiratory and expiratory phases were separately selected and used to produce multigated images for the respective phases. Twelve patients with normal LV ejection fraction (EF) (greater than 50%) and right ventricular (RV) EF (greater than 40%) and without pulmonary diseases were studied. LV end-diastolic volume (EDV) decreased during inspiration in all subjects (by 11 +/- 5%), whereas LV end-systolic volume (ESV) was insignificantly changed. Accordingly, LVSV decreased during inspiration in all subjects (by 17 +/- 7%). LVEF decreased from 64 +/- 6% during expiration to 60 +/- 6% during inspiration (p less than 0.001). In contrast to the left ventricle, RVEDV and RVSV increased during inspiration by 13 +/- 11% and 22 +/- 18%, respectively. RVESV did not change significantly. RVEF increased from 48 +/- 6% during expiration to 52 +/- 5% during inspiration (p less than 0.05). These results indicate that inspiratory reduction of LVSV during spontaneous respiration is due to a decrease in LVEDV which may be derived from an increase in RVEDV during inspiration through the mechanism of ventricular interdependence.
The nucleotide sequence of the malate dehydrogenase (mdh) gene from a thermophilic bacterium, Thermus flavus, was determined. The amino acid sequence of the Thermus malate dehydrogenase resembled that of the porcine heart cytoplasmic enzyme to a certain extent, and Asp-159 and His-187 were identified as possible essential residues for the catalytic function. The mutated mdh gene was also cloned from a spontaneous mutant of T. flavus containing a higher activity of the enzyme. Its mutation point was determined to be a single nucleotide exchange from C to T which caused Thr-190 to be substituted by isoleucine. The mutated enzyme showed resistance to substrate inhibition, an increase in both kcat and Km, and a shift toward a more acid optimum pH for the enzyme reaction.
The chronic effects of the oral administration of OPC-8212 (3,4-dihydro-6-[4-(3,4-dimethoxybenzoyl)-1-piperazinyl]-2(1H)-quinolinon e) on resting hemodynamics and exercise capacity were assessed in 15 patients with congestive heart failure (NYHA II-IV). Doses of 30 or 60 mg per day were given per os over 3.0 weeks on average (range 2-6 weeks). Multigated radionuclide ventriculography and multistage exercise testing were performed before and during OPC-8212 therapy to assess the changes in left ventricular volume and exercise capacity respectively. Systolic blood pressure showed a slight increase (from 123 +/- 3 to 129 +/- 4 mmHg) during OPC-8212 therapy, while heart rate was unchanged (69 +/- 3 vs 67 +/- 3 beats/min). The left ventricular end-diastolic volume index decreased from 127 +/- 9 to 107 +/- 7 ml/m2, and ejection fraction and the P/V index (the ratio of peak systolic pressure to left ventricular end-systolic volume index) increased during OPC-8212 therapy (from 27% +/- 3% to 30% +/- 4% and from 1.5 +/- 0.2 to 2.0 +/- 0.3 mmHg/ml/m2 respectively). NYHA functional class was improved in 9 of 15 patients, and the average peak work load achieved during exercise testing increased from 27 +/- 6 to 47 +/- 7 W. No significant adverse effect was observed in any patient. These results indicate that OPC-8212 enhances the inotropic state and, hence, reduces heart size with no change in heart rate. Moreover, it increases exercise capacity. Thus, OPC-8212 is an inotropic agent with promise for application in the long-term treatment of congestive heart failure.
The present paper demonstrates a handheld computer system for use in perinatal care. The features of the system are as follows: The gestational age and fetal body weight were determined by analyzing the data from ultrasonography with the high-order regressive equation. The combined use of the linear regressive equation and Ott's equation was more useful in precisely calculating the fetal abdominal circumference. In order to decrease input error, attempts were made to minimize key-operations for data-entry. The use of the screen edition system also made it easier to correct input error. It was concluded that this system was practical and easy to handle, and would be a useful aid in clinical care.
The enzymic inactivation of cephamycins, i.e. cefoxitin, cefmetazole, cefotetan and cefbuperazone, was investigated by means of bioassay, high pressure liquid chromatography (HPLC) and spectrophotometric analysis using three types of cephalosporinase (CSase, RICHMOND type Ia, Ib and Ic) and one penicillinase (PCase, TEM type). These four cephamycins were not inactivated by Ic CSase and TEM type PCase or producers of these enzymes. However, the inactivation of cefmetazole and cefoxitin was noted when they were incubated in the cultures of CSase (Ia and Ib)-producers or incubated with a large amount of these purified enzymes although the inactivation of cefbuperazone was not noted. HPLC of culture fluid or enzyme solution which contained cefmetazole or cefoxitin and were incubated at 37 degrees C showed that metabolites of cefmetazole or cefoxitin appeared as the drug disappeared. In addition, the appearance of metabolites corresponded to the loss of the drug's bioactivities and the absorption of iodine. UV and IR spectra of cefmetazole which were taken after incubation with the purified CSase showed the cleavage of the beta-lactam ring.
The activity of cefoperazone against a strain with an inducible cephalosporinase and a mutant that produces the enzyme constitutively indicates that the low inducer activity of this antibiotic plays an important role in its activity against Enterobacter cloacae.
The inducer activity of seven penicillins for cephalosporinase (CSase) production and their antibacterial activity against CSase-producing strains were studied using clinical isolates of Proteus morganii, P. rettgeri, P. vulgaris, Enterobacter cloacae, and Serratia marcescens. Piperacillin, apalcillin, and methicillin showed rather low inducer activity for CSase production in all strains tested. On the other hand, ampicillin, carbenicillin, and sulbenicillin showed high inducer activity for CSase production. Piperacillin, apalcillin, and ampicillin were less stable to CSases than were carbenicillin, sulbenicillin, and methicillin, but much more stable than benzylpenicillin. In the growing culture of CSase-producing strains, piperacillin and apalcillin were rather stable. Against CSase-producing strains, piperacillin and apalcillin were more active than other penicillins tested.
The purified cephalosporinase from Proteus vulgaris hydrolyzed a variety of cephalosporins, including cefuroxime, at a high level; its activity was inhibited by clavulanic acid.
Antiserum against purified beta-lactamase from Proteus vulgaris GN7919 cross-reacted with beta-lactamases produced by strains of Pseudomonas cepacia in a neutralization test. Anti-P. cepacia beta-lactamase serum, however, did not show any cross-reactions with P. vulgaris beta-lactamases. Each of these enzymes can hydrolyze cefuroxime and cefotaxime.
Cefoperazone (T-1551, CFP) a new semisynthetic cephalosporin, has a broad spectrum of antibacterial activity. We investigated the affinity of CFP to penicillin-binding proteins (PBPs) and the inhibition of peptidoglycan synthesis by CFP. CFP had high affinities for Escherichia coli PBP-3, -1Bs, -2, and -1A, in descending order, and low affinities for PBP-4, -5, and -6. Similarly, CFP showed high affinity for Pseudomonas aeruginosa PBP-3, -1A, -1B, -2, and -4, in descending order. It is known that E. coli PBP-3 and P. aeruginosa PBP-3 participate in cell division. These results are in good agreement with the formation of filamentous cells of E. coli and P. aeruginosa treated with CFP. CFP had lower inhibitory activities on D-alanine carboxypeptidase IA and IB of E. coli than that of penicillin G, but its inhibitory activities on the cross-link formation in peptidoglycan synthesis were the same as those of penicillin G and higher than those of ampicillin.
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