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Biomedical subjects

M Kono

Publications and source records attributed to M Kono.

At least 199 records · Page 11Linked to original sources
PubMed1991

Ultrasonic tissue characterization of chronic liver disease using cepstral analysis.

To evaluate the morphological changes in chronic liver disease by means of ultrasonography, cepstral analysis was applied to the ultrasonic waveforms obtained with a 10-MHz transducer during peritoneoscopy. Assuming that liver tissue was a collection of semiregularly arrayed small scatters of ultrasound, the spaces between scatterers of the liver could be measured by means of cepstral analysis. From the distribution of the spaces between scatterers, two statistical parameters, mode and kurtosis, were determined for each patient. The mode of spaces between scatterers for liver cirrhosis was significantly larger than that for chronic hepatitis and nonspecific change. The mode of spaces between scatterers was correlated with the size of hepatic lobules or nodules. The kurtosis of spaces between scatterers for chronic hepatitis and liver cirrhosis was significantly smaller than that for nonspecific change. As a preliminary study for noninvasive application of this technique, cepstral analysis was also applied to the ultrasonogram obtained through the abdominal wall with a 3.5-MHz transducer. The results obtained with a 3.5-MHz transducer were correlated well with those obtained with a 10-MHz transducer. These results suggest the possibility of noninvasive evaluation of the structural changes in chronic liver disease.

Chronic Disease↗
PubMed1991

Preparation and characterization of labelled interferon-gamma and the development of radioreceptor assay for interferon-gamma.

A 125I-labelled recombinant interferon-gamma (IFN-gamma) was prepared by the lactoperoxidase-glucose oxidase method. The specific activity of the labelled IFN-gamma was 31 Bq U-1 and its molecular weight, immunoreactivity and receptor binding ability remained the same after the labelling. Using the labelled IFN-gamma and FL5(-1) cells from human amniotic membrane, a radioreceptor assay was developed. Natural IFN-gamma, recombinant IFN-gamma and the labelled IFN-gamma were observed to bind to the same binding sites on the cells with similar affinity (Kd = 1.3-2.2 x 10(-10) M). The radioreceptor assay was more specific than a bioassay because the labelled IFN-gamma did not compete with IFN-alpha or IFN-beta. It was much more sensitive (90 pM) than conventional competitive radioimmunoassay (300 pM) using the same labelled IFN-gamma, and as sensitive as immunoenzymometric assay (60 pM). The radioreceptor assay should be useful not only for research on IFN-gamma but also for the determination of biological activity in process control and/or quality control of IFN-gamma manufacturing.

Binding, Competitive↗
PubMed1991

Effect of pH buffer molecules on the light-induced currents from oriented purple membrane.

The effect of pH buffers on the microsecond photocurrent component, B2, of oriented purple membranes has been studied. We found that under low salt conditions (less than 10 mM monovalent cationic salt) pH buffers can dramatically alter the waveform of the B2 component. The effect is induced by the protonation process of the buffer molecules by protons expelled from the membrane. These effects can be classified according to the charge transition upon protonation of the buffer. Buffers that carry two positive charges in their protonated form add a negative current component (N component) to B2. Almost all of the other buffers add a positive current component (P component) to B2, which is essentially a mirror image of the N component. Buffers with a pK less than 5.5 have only a small positive buffer component. The pH dependence of the buffer effect is closely related to the pK of the buffer; it requires that the buffer be in its unprotonated form. The rise time of the buffer component increases with the concentration of the buffer molecules. All the buffer effects can be inhibited by the addition of 5 mM of a divalent cation such as Ca2+. Reducing the surface potential slows down the N component but accelerates the P component without affecting the amplitude of the buffer effect significantly. Many of the buffer effects can be explained if we assume that upon protonation of the buffer by a proton expelled from the membrane by light, the buffer molecules move toward the membrane. This backward movement of buffer molecules forms a counter current very similar to that due to cations discussed in Liu, S. Y., R. Govindjee, and T. G. Ebrey. (1990. Biophys. J. 57:951-963).

Bacteriorhodopsins↗
PubMed1991

Two pathways for GM2(NeuGc) expression in mice: genetic analysis.

We have reported that WHT/Ht mice express neither GM2(NeuGc) nor GM1(NeuGc) in the liver or erythrocytes due to a defect on the Ggm-2 gene, which was demonstrated to control the activity of UDP-GalNAc:GM3(NeuGc) N-acetylgalactosaminyltransferase in mouse liver, and, in addition, WHT/Ht mice do not express a detectable amount of GM2(NeuGc) but do express GM1(NeuGc) in tissues other than the liver and erythrocytes, such as the spleen, thymus, heart, lung, kidney, and testis [Nakamura et al. (1988) J. Biochem. 103, 201-208]. In order to determine whether the phenotype of WHT/Ht mice exhibiting an undetectable amount of GM2(NeuGc) in these tissues is genetically controlled or not, we analyzed the expression of gangliosides in the progeny obtained on backcross mating between (BALB/c X WHT/Ht)F1 and WHT/Ht mice, and in a GM2(NeuGc) congenic mouse, WHT.C. Concerning the expression of GM2(NeuGc) in the liver, lung, and kidney, 102 backcross mice could be segregated into two types. One type expressed a detectable amount of GM2(NeuGc) in the liver, lung, and kidney, and the other type did not. The ratio of the numbers of mice exhibiting these two types was 42: 60, indicating that the two phenotypes were genetically determined by the involvement of a single autosomal gene. Recombination as to GM2(NeuGc) expression in the liver, lung, and kidney was not detected among the 102 backcross mice. Analysis of the GM2(NeuGc) congenic mouse indicated that a detectable amount of GM2(NeuGc) was expressed in the liver, erythrocytes, lung, kidney, heart, spleen, and small intestine.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Clinical usefulness of serum phospholipase A2 determination in patients with pancreatic diseases.

A new kit for radioimmunoassay of serum phospholipase A2 (PLA2) with monoclonal antibody (S-0932, Shionogi, Osaka, Japan) was used to examine PLA2 levels in patients with various diseases. Patients with acute pancreatitis showed significantly increased serum PLA2 levels. In patients with chronic pancreatitis, significant correlations were observed between the levels of factors evaluated by the secretin test and serum PLA2 levels. In patients with pancreatic cancer, serum PLA2 levels varied with disease severity. Serum PLA2 concentrations were within the normal range in patients with other malignant tumors, diabetes mellitus, and chronic liver diseases but were increased in patients with chronic renal failure. S-Sepharose column analysis of sera showed a small peak of pro-PLA2 and a large peak of PLA2 in sera from patients with severe acute pancreatitis, but a large peak of pro-PLA2 in healthy controls and patients with other diseases. On G-100 gel filtration, high-molecular-weight PLA2 immunoreactivity was detected in sera of patients with chronic renal failure, whereas a single peak of PLA2 immunoreactivity coinciding with that of standard PLA2 was detected in sera of patients with acute pancreatitis. These results suggest that (a) measurement of serum PLA2 is clinically useful for diagnosis and monitoring of pancreatitis, (b) active PLA2 in the circulation is dominant in severe acute pancreatitis, and (c) the kidney may be the main site of PLA2 degradation or excretion.

Acute Disease↗
PubMed1991

Effects of hydralazine and prostaglandin E1 on regional myocardial function in the ischemic canine heart.

The effects of hydralazine and prostaglandin E1 on regional myocardial function were studied in dogs. Sixteen dogs were randomly assigned to one of two drug treatment groups of eight dogs each. The first group (G1) was treated with 0.4 mg/kg hydralazine administered as a bolus. The second group (G2) received prostaglandin E1 given as an infusion for a total dose of 0.8 micrograms/kg. Regional myocardial function was assessed through the measurement of myocardial segment shortening during systole. We call this index percent systolic shortening (%SS). An ischemic heart preparation was created by partial occlusion of coronary blood flow. The degree of induced ischemia was determined by following the reduction in %SS. Hydralazine reduced %SS of the ischemic myocardium while increasing the cardiac index, stroke volume index, and coronary blood flow. Prostaglandin E1 increased %SS, cardiac index, and stroke volume index in the ischemic heart preparation. Hydralazine, therefore, induced dissociation between global ventricular function and regional myocardial function whereas prostaglandin E1 did not. The present findings emphasize that evaluation of vasoactive drugs should consider their effects on regional myocardial function as well as on global hemodynamics.

Alprostadil↗
PubMed1991

Obesity and liver disease: evaluation of fatty infiltration of the liver using ultrasonic attenuation.

We developed an in vivo ultrasonic attenuation measurement system with which we attempted to evaluate the degree of fatty infiltration in the liver. In an animal study, fatty liver was induced in rabbits, and ultrasonic radiofrequency waveforms from the liver were obtained using a 10 MHz A mode transducer. Frequency-dependent attenuation of the ultrasound, which was correlated with total lipid content, was calculated using a spectral difference method. In a human study, ultrasonic waveforms were obtained using a 3.5 MHz transducer. Frequency-dependent attenuation also showed a significant correlation with the grading of fatty infiltration of the liver. These results suggested that fatty infiltration of the liver could be evaluated quantitatively and noninvasively using frequency-dependent attenuation of the ultrasound.

Animals↗
PubMed1991

The derivation of a novel mitomycin skeleton: 3 alpha-alkoxymitomycin.

The first example of C-3 alkoxylation in mitomycins has been achieved. 3 alpha-iso-Propoxy-10-O-decarbamoylmitomycin D (4) and 3 alpha-iso-propoxymitomycin D (5) were derived from mitomycin D (3) under decarbamoylation conditions with iso-propoxide. Under similar conditions 3 alpha-iso-propoxy-10-O-decarbamoylporfiromycin (8) and 3 alpha-methoxy-10-O-decarbamoylmitomycin B (11) were also derived from porfiromycin (6) and mitomycin B (9), respectively. The mechanism of generation of these novel analogs was based on the premise that the key intermediate of hydroquinone iminium salt (14) was led through the iminium salt (13), followed by alkoxide addition and oxidation.

Mass Spectrometry↗
PubMed1991

The configuration of mitiromycin and its derivation from mitomycin B.

The configuration of mitiromycin (2) was first determined by NMR experiments including the NOE technique. The absolute structure of 2 was related to mitomycin B (3) because 2 was derived from 3 under basic conditions. The ketonic form 4 was presumed to be involved in the generation of 2.

Antibiotics, Antineoplastic↗
PubMed1991

Cepstral analysis of ultrasound in chronic liver disease--a preliminary study in the non-invasive evaluation of structural change.

To evaluate the morphological changes in chronic liver disease non-invasively we used the frequency-domain analysis of ultrasound. We assumed that liver tissue is a collection of semi-regularly arrayed small scatterers of ultrasound. We applied cepstral analysis to ultrasonic waveforms and evaluated the periodicity of scalloping of the power spectrum, caused by an interference effect among liver scatterers of a given spacing. In a phantom experiment, we could correctly measure the space among scatterers of a phantom consisting of a regularly spaced distribution of nylon filaments. In an experiment involving a freshly excised porcine liver, the distribution of the space among scatterers (SAS) determined on cepstral analysis reflected the size distribution of the hepatic lobules. In a human study, two statistical parameters, mode and kurtosis, were determined from the distribution of the SAS for each patient. In a previous study, we collected ultrasonic data during peritoneoscopy with a 10 MHz transducer directly contacting the liver and showed that we could evaluate morphological changes in chronic liver disease using cepstral analysis. In the present study, we obtained data in two ways: with a 3.5 MHz transducer through the abdominal wall and with a 10 MHz transducer directly contacting the liver during peritoneoscopy. The mode and kurtosis of the SAS obtained with the 3.5 MHz transducer were both well correlated with the mode and kurtosis of the SAS obtained with the 10 MHz transducer. These results suggest that we can evaluate morphological changes in chronic liver disease non-invasively.

Animals↗
PubMed1991

[Radionuclide cavography before and after percutaneous transluminal angioplasty in Budd-Chiari web: case report].

A case of the Budd-Chiari syndrome due to a web of the hepatic inferior vena cava (IVC) is reported. A 54-year-old male with mild liver dysfunction was suspected with IVC obstruction from the screening CT which revealed liver cirrhosis with marked caudate lobe enlargement and dilatation of azygous and hemiazygous vein. Subsequent radionuclide cavography with 99mTc-HSA clearly demonstrated IVC obstruction, but failed to clarify the site or type of the obstruction. Finally contrast cavography diagnosed a web of the hepatic IVC, which was treated by percutaneous transluminal angioplasty (PTA). During two-year follow-up after PTA none of the radionuclide cavographies showed reocclusion of the IVC and as a result contrast cavography was avoided. Radionuclide cavography, therefore, was a useful method for evaluating IVC obstruction before and after PTA for the Budd-Chiari web.

Angioplasty, Balloon, Coronary↗
PubMed1991

[Temporal integration in diseased eyes. I. Exposure duration in visual acuity testing].

Critical duration in visual acuity testing can be viewed as an expression of temporal integration in the human visual system. We examined this phenomenon in 13 eyes with central serous retinopathy (CSR) and 6 eyes with macular edema, by measuring visual acuity at several limited exposure times. The results were then compared with those for 17 normal eyes. The acuity target was a single Landolt ring projected upon a small square screen. The size, direction, and exposure time of the target were computer controlled. The mean critical durations of the CSR and macular edema groups were 1.78 sec. and 2.69 sec. respectively. These values were significantly (p less than 0.01) longer than the mean critical duration of the normal control group (0.62 sec.). Although the mechanism behind the longer critical duration in diseased eyes remains poorly understood, we believe this method provides a possible approach to the study of diseased visual conditions.

Humans↗
PubMed1990

[Application of an angiographic catheter with side holes to intra-arterial drug infusion--improvement of drug distribution by occlusion of the catheter tip].

To improve distribution of drug by intraarterial infusion a new catheter system with sideholes, tip of which was able to be occluded by an embolus, was developed. Inner diameter of the catheter was 0.038 inch. Tip of the catheter was so smoothly tapered to 0.025 inch in inner diameter that it could be occluded by an embolus of 0.038 inch in diameter. After occlusion of the tip, drug flowed out rectangly to catheter axis from only sideholes, resulting that drug flowed out was mixtured by blood stream to make a uniform distribution of it.

Catheterization↗
PubMed1990

[Scrotal scintigraphy in the diagnosis and grading of varicocele].

Scrotal scintigraphy with 99mTc-red blood cells has been reported as a useful method for detecting varicocele. In this study we analysed the scintigraphy of 251 infertile males with clinically diagnosed or suspected varicocele, in an attempt to establish a grading system of varicocele. Scintigraphically varicocele was diagnosed in 207 patients on the basis of pooling in hemiscrotum in static images and/or early flow through the spermatic cord vessels in dynamic images; physical examination overlooked 17 of them. Of the 207 patients, all had pooling (153 left-sided, 1 right-sided, and 53 bilateral pooling) and 52 had early flow. The early flow was a less sensitive sign for varicocele than the pooling and invariably accompanied by the intense pooling. The early flow may be related to increased shunt flow through varicocele. According to the scintigraphic findings, varicocele was classified as follows: Grade I (small varicocele with faint early flow or mild localized pooling, n = 103), Grade II (medium varicocele with obvious early flow or curvilinear mottled pooling, n = 67) and Grade III (large varicocele with marked early flow or pooling, n = 37). Clinical assessment (93 small, 68 medium, and 54 large varicocele) supported the scintigraphic classification. Scrotal scintigraphy, therefore, facilitates precise evaluation of varicocele based on its morphology and hemodynamics.

Adult↗