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Biomedical subjects

F Kondo

Publications and source records attributed to F Kondo.

At least 91 records · Page 5Linked to original sources
PubMed1995

Growth patterns and interstitial invasion of small hepatocellular carcinoma.

Twenty-five cases of small hepatocellular carcinoma (HCC; diameter < or = 30 mm) were evaluated for overall morphologic features and growth patterns. The tumors often showed a well-differentiated, normotrabecular histologic pattern and insidious interstitial invasion, which resembled benign hepatocytes scattered in connective tissues. As the tumor grew, a less-differentiated tumor area became predominant. Portal tracts included in small HCC nodules were quantitatively assessed, revealing that they progressively reduced in number with tumor growth. The tumor margin was often reported to be unclear. The present results indicate that the histologic grade of tumor differentiation, capsular formation, existence of liver cirrhosis and patterns of interstitial invasion are important factors for determining the nature of the margin. The score of argyrophilic nuclear organizer regions (AgNOR) was examined in 5 cases showing typical interstitial invasion with the insidious type. In each case, the AgNOR score of the invading tumor cells was lower than that of tumor cells within the HCC nodules, but higher than benign hepatocytes in cirrhotic parenchyma. It clarified that the growth activity of well-differentiated HCC was rather suppressed upon their interstitial invasion.

Carcinoma, Hepatocellular↗
PubMed1995

Therapeutic effect of percutaneous ethanol injection on small hepatocellular carcinoma: evaluation with CT.

PURPOSE: To evaluate the therapeutic effect of percutaneous ethanol injection (PEI) on small hepatocellular carcinoma (HCC) with computed tomography (CT). MATERIALS AND METHODS: Sixty-seven patients with histologically proved HCC 3 cm or less in diameter underwent PEI. The patients were regularly followed up with sonography and contrast material-enhanced CT for more than 1 year (range, 12-96 months). The CT findings were evaluated for three tumor types distinguished on the basis of their appearance relative to that of the surrounding liver parenchyma: type 1 = hyperattenuating at the early phase (n = 39), type 2 = iso- or hypoattenuating at the early phase and hypoattenuating at the late phase (n = 18), and type 3 = isoattenuating (not detected) at both the early and late phases (n = 10). RESULTS: After PEI, a necrotic area of HCC and the surrounding liver parenchyma was characterized as hypoattenuating at both early and late phases of contrast-enhanced CT, regardless of the type. When an HCC appeared to be completely necrotic within 3 months after PEI, this status was retained until the latest observation in all but three cases. CONCLUSION: Contrast-enhanced CT can correctly depict PEI-induced necrosis in HCC and is reliable for evaluating the therapeutic effect of PEI.

Carcinoma, Hepatocellular↗
PubMed1995

Simultaneous identification and determination of residual penicillins by use of high-performance liquid chromatography with spectrophotometric or fluorometric detectors.

Using 7 penicillins (amoxicillin, ampicillin, methicillin, penicillin G, oxacillin, cloxacillin, and dicloxacillin), simultaneous and direct determination of residual penicillins in biological samples was carried out by use of bioassay and high-performance liquid chromatography with spectrophotometric or fluorometric detectors. By use of assay medium seeded with penicillin-sensitive Micrococcus luteus (ATCC No. 9341) as a test organism, we were able to detect penicillins even at low concentrations. All penicillins treated with 10 U of penicillinase/ml did not produce inhibition zones by disk testing, even at a concentration of 100 micrograms of penicillin/ml/assay plate. Using a mobile phase of acetonitrile:methanol: 0.01M KH2PO4 (19:11:70, v/v/v; pH, 7.1), standard solutions of the penicillins were separated from each other by use of high-performance liquid chromatography analysis, producing symmetric peaks without tailing, each of which had a characteristic retention time. Simultaneous detection of residual penicillins in bovine serum, kidneys, and liver, for the 5 penicillins for which analysis was possible by use of the UV method, yielded recovery rates from 71.4 to 102.3%; for the 2 amino-penicillins, amoxicillin and ampicillin, which could only be detected by use of the fluorometric method, recovery rate ranged from 72.9 to 103%.

Animals↗
PubMed1994

Simple continuous and simultaneous determination of tetracycline residues.

A new continuous separation method was developed for the determination of five different tetracyclines (oxytetracycline, tetracycline, chlortetracycline, methacycline and doxycycline). A bioassay using minimum medium (MM) seeded with Bacillus subtilis ATCC 6633 was carried out for the detection, with simple extraction from the agar block of the clear inhibition zone on the MM produced by the mixed tetracyclines. The extract was subjected to continuous identification by high performance liquid chromatography using a mu-Bondapack C18 column. The tetracyclines were separated at ambient temperature using a mobile phase of 0.01 M oxalic acid: acetonitrile: N,N-dimethylformamide (74:18:8, v/v/v) at a flow rate of 1.0 ml min-1. A variable-wavelength detector set at 355 nm and recorder set at 4 mm min-1 were used for the detection. The entire mixture was resolved as five peaks with retention times ranging from 2.75 to 9.65 minutes. This continuous, simple and rapid method of detection, extraction and identification may be useful for routine laboratory testing of residual antimicrobial agents in food.

Bacillus subtilis↗
PubMed1994

A clean-up method for analysis of trace amounts of microcystins in lake water.

A clean-up method using high performance liquid chromatography (HPLC) and liquid chromatography/mass spectrometry (LC/MS) was developed to pursue trace amounts of microcystins in lake water. The method consisted of the combined usage of octadecyl silanized (ODS) silica gel and silica gel cartridges. In the first clean-up process, the retention behavior of microcystin RR on ODS silica gel cartridge was carefully observed together with microcystin LR, and 10% water-methanol was chosen as the best solvent system to elute microcystins from the ODS silica gel cartridge. Because many impurities still remained in the desired fraction from the raw water even after the clean-up with ODS silica gel, an additional clean-up process was developed using various cartridges. As a result of extensive experiments, the second clean-up process using silica gel cartridge was established, and the impurities were effectively eliminated. The present method including a tandem cartridge system allowed a precise analysis of microcystins in water samples from three different lakes at a 0.02 ppb level.

Chromatography, High Pressure Liquid↗
PubMed1994

Liquid chromatographic determination of salbutamol and clenbuterol residues in swine serum and muscle.

A simple and rapid method has been developed for determination of residual clenbuterol and salbutamol in swine serum and muscle using high-performance liquid chromatography. In a Nova-pak C18 column, the drug peaks were separated by a gradient using two mobile phases [acetonitrile:water (15:85, v/v) and acetonitrile:water (30:70, v/v)] for salbutamol and clenbuterol, respectively. A photodiode array set at 196 nm for salbutamol and 210 nm for clenbuterol, -0.01 to +0.2 AU, ambient temperature and flow rate of 1.0 ml/min, were used. The retention times were 5.4 and 21 min for salbutamol and clenbuterol, respectively. The detection limits for this method were 0.1 and 0.2 microliter/ml for salbutamol and clenbuterol, respectively. Average recoveries (0.1, 0.25, 0.5, 1.0 ppm spiked level) were 86.7 +/- 1.7% for salbutamol; 80.0 +/- 2.0% for clenbuterol spiked in serum; 64.2 +/- 8.9% for salbutamol; 62.9 +/- 4.2% for clenbuterol spiked in the muscle, respectively. The minimum detectable amount was 0.1 ppm, based on a spiked sample extract.

Albuterol↗
PubMed1994

[An angiographic study on the pathological features of multiple hepatocellular carcinoma].

Seventy-one patients with untreated hepatocellular carcinoma (111 tumors) were studied angiographically to investigate the pathological features of multiple carcinoma. The 111 tumors comprised 23 lesions resected from 14 patients and 88 lesions measuring 3 cm or less in diameter detected in 57 patients who did not undergo resection. Hemodynamically, major lesions exhibited an increase in frequency of tumor angiogenesis and intensity of tumor stain with an increase in diameter. Analysis of angiographic features of tumors measuring 2 cm or less in diameter revealed a greater vascularity in intrahepatic metastatic foci than in primary foci, demonstrating a difference between them. When multiple tumors were classified into the isolated, concentric or disseminated type in terms of the pattern of their distribution, their angiographic findings suggested that min or lesions of the concentric or disseminated type might represent local metastases spread from the primary focus, and that those of the isolated type might represent multicentric occurrence in the liver.

Aged↗
PubMed1994

A simple method for classification of antibiotics using ion exchange resins added to agar plates.

Using two different ion-exchange resins (Dowex 50W-X4 as cation and Dowex 1-X4 as anion) added directly to assay plates seeded with Bacillus subtilis or Micrococcus luteus, the size of the inhibitory zone produced by 36 antimicrobial agents around a disc or cup was characterized into various types, such as acidic, basic or amphoteric. An increase of the inhibition zone following addition of 15% Dowex 50W-X4 was evident in penicillins except for ampicillin and penicillin-G, and polyethers. Aminoglycosides, macrolides and colistin, lincomycin, and sulphonamides on assay medium treated with Dowex 1-X4 showed a similar effect on the inhibition zone. Tetracyclines, virginiamycin, oxolinic acid and furazoridone revealed no effects on the inhibition zone with either of the resins. These antibiotics could be divided into various groups on the basis of their chemical structure. This simple and rapid method may be useful for routine laboratory testing of residual antibiotics in meat.

Anion Exchange Resins↗
PubMed1994

Determination of pyridonecarboxylic acids in plasma by reverse-phase high-performance liquid chromatography.

A simple qualitative and quantitative determination for pyridonecarboxylic acids including nalidixic acid (NA), oxolinic acid (OA) and pipemidic acid (PPA) in chicken plasma was carried out by microbiological, spectrophotometric, thin-layer chromatographic (TLC) and reverse-phase high-performance liquid chromatographic (HPLC) methods. As a test organism for bacteriological bioassay, Bacillus subtilis ATCC-6633 was the most sensitive of seven organisms investigated. Using the cup and the disc methods, a standard curve was obtained by determining the relationship between various drug concentrations and the diameter of the inhibition zone. The three drugs had two strong UV absorbance wavelengths (257 and 330 nm) on spectrophotometry. TLC analysis using a silica gel 60 F254 plate was investigated, and a solution of methanol:chloroform:acetic acid (3:1:1, v/v/v) was found to be the most suitable solvent for separation. The minimum concentration of drug detectable by this method was 0.5 microgram/ml for NA, 0.075 microgram/ml for OA and 0.39 microgram/ml for PPA. For HPLC analysis, a solution of acetonitrile:0.2 M phosphoric acid (1:1, v/v) was superior, and simultaneous determination of all three drugs was possible under the HPLC conditions used. The lowest measurable amount of drug in chicken plasma was 0.01 microgram/g. Recovery from extracts spiked with each drug at a known concentration was close to 100% for NA and OA, but only about 50% for PPA.

Animals↗
PubMed1994

Simple bacteriological and thin-layer chromatographic methods for determination of individual drug concentrations treated with penicillin-G in combination with one of the aminoglycosides.

For the individual determination of residual drug concentrations in meat when using penicillin-G (PC-G) in combination with one of the aminoglycoside antibiotics, the differentiation of PC-G and the aminoglycoside groups was easily accomplished by incubation of the individual drug with penicillinase (PCase). Each aminoglycoside treated with PCase (50 U/ml) produced a similar clear inhibition zone by the aminoglycoside alone, but PC-G treated with PCase produced no inhibition zone even when a high concentration of 100 microg/ml of PC-G was used on the assay plates seeded with Bacillus subtilis or Micrococcus luteus. Furthermore, these drugs could be distinguished and identified according to their characteristic Rf values and colours by the TLC method using silica-gel 60 F254 plates followed by spraying with various chemical reagents. A solution of n-butanol:acetic acid:water:p-toluenesulphonic acid (3:1:1:0.7) was the best developing solvent for the separation of all the antibiotics.

Aminoglycosides↗
PubMed1993

A reverse-phase high-performance liquid chromatographic determination of nicarbazin residues in eggs.

A reverse-phase high-performance liquid chromatographic (HPLC) method was employed for analysis of nicarbazin [1:1 mixture of 4,4'-dinitrocarbanilide (DNC) and 2-hydroxy-4, 6-dimethyl-pyrimidine] in chicken eggs. Nicarbazin residues were analysed by determining the DNC of nicarbazin. HPLC of the DNC portion of nicarbazin was performed with a reverse-phase mu-Bondapak C18 column, using a mobile phase of acetonitrile-water (7:3, v/v). A variable-wavelength detector set at 340 nm, 0.02 AUFS, and a recorder set at 4 mm/min were used for the detection. The standard curve for nicarbazin was linear within the range 0.05-2.0 micrograms/ml. The recovery of nicarbazin added to eggs was 90.2%. The detection limit of nicarbazin in this analytical method was 0.005 micrograms/ml. Nicarbazin was detected in 10% of eggs obtained by feeding chickens with a diet contaminated with nicarbazin within the range 0.07 to 1.39 micrograms/g, but it was not detected in eggs obtained commercially.

Animal Feed↗
PubMed1993

[Usefulness of percutaneous biopsy under sonographic control and histological examination in the early diagnosis of hepatocellular carcinoma].

We evaluated the usefulness of percutaneous biopsy under sonographic control and histological examination in the early diagnosis of hepatocellular carcinoma (HCC) in comparison with CT and angiography. 121 patients in whom hepatic nodules 3cm or smaller in size were found by ultrasound as suspected HCC underwent percutaneous biopsy, CT and angiography. 118 patients were finally diagnosed as HCC. Correct diagnosis of HCC was obtained by each modality in relation to tumor size as follows: 87.3% by histological examination, 55.1% by CT, 52.5% by angiography. However, the diagnostic capability of these modalities for HCC 1.5cm or smaller in size was as follows: 88.5% by histological examination, 34.6% by CT, and 23.1% by angiography. Cytology using a biopsy specimen was performed in 26 patients and it showed a positivity of 61.5%. In conclusion, for a definitive diagnosis of small HCC 1.5cm or less in size, the current imaging modalities have some limitations. On the other hand, percutaneous biopsy and histological examination are the most reliable and indispensable for making a definite diagnosis of small HCC.

Adult↗
PubMed1993

A continuous, simple and rapid method for the detection, extraction and identification of residual antibacterial agents in meat.

Most antibacterial agents produced larger inhibition zones and showed lower detectable concentrations on minimal medium (MM) seeded with Bacillus subtilis than on Mueller-Hinton medium. After simple extraction, using a small amount of acetonitrile, from an agar block inside the inhibitory zone produced by each antibacterial agent, identification was carried out by reverse-phase high-performance liquid chromatography (HPLC). It is recommended that for inspection of residues MM is superior as a bioassay medium. The continuous, simple and rapid method described may be useful for routine laboratory testing of residual antimicrobial agents in food.

Anti-Bacterial Agents↗
PubMed1992

Separation and identification of microcystins in cyanobacteria by frit-fast atom bombardment liquid chromatography/mass spectrometry.

In order to separate and identify microcystins, a new analytical method was developed using a frit probe as an interface for fast atom bombardment mass spectral analysis of high performance liquid chromatographic (HPLC) effluents. Two types of HPLC conditions were designed for separation of standard microcystins RR, YR and LR. The HPLC conditions, for example, methanol:0.01% trifluoroacetic acid = 61:39 (containing 0.8% glycerol) as a mobile phase and 0.5 ml/min as a flow rate, provided a base line separation of standard microcystins RR, YR and LR. The HPLC conditions were also effective for separation of the non-toxic geometrical isomers of microcystins RR and LR. The total ion chromatogram of a mixture of standard microcystins showed excellent correlation with the HPLC separation using a u.v. detector. The method was subsequently applied to analysis of microcystins contained in both a culture strain and a field sample, and the procedure from toxin extraction to identification of microcystins was performed within 1 day. The mass chromatogram monitored at m/z 135 that is always observed with abundance in the FAB mass spectra of the purified microcystins, differentiated between microcystins and other types of compounds. This technique allowed the rapid identification of unknown microcystins without standard samples. Additionally, compounds other than microcystins were also found, which would not be seen by u.v. detection at 238 nm.

Chromatography, High Pressure Liquid↗
PubMed1992

[Study of sonographic findings of small hepatocellular carcinoma based on its pathologic findings].

Sonograms of 282 cases of hepatocellular carcinoma (HCC) less than 5 cm in size were examined. Among these, 73 cases of resected or biopsied HCCs were compared in terms of their pathologic findings and sonograms. Low echoic pattern was the more common among smaller HCCs, and low echoic periphery pattern tended to prevail with increasing size. The pathologic factors of fatty change and clear cell formation are responsible for elevating the echo level. Among HCCs less than 2 cm, the low echoic group is more differentiated than the iso-echoic group by Edmondson's classification. "Lateral acoustic shadow", "nodule in nodule", and "septum" are characteristic findings in HCC by sonography, and they correspond to the pathologic findings. However, "posterior echo enhancement" was not seen to be specific for HCC, as it was also observed with similarly frequency in hemangiomas.

Adult↗
PubMed1992

[Diagnostic significance of angiography for small hepatocellular carcinoma--comparison with other examinations].

The diagnostic value of angiography for small hepatocellular carcinoma was evaluated in comparison with histology, contrast-enhanced computed tomography, and ultrasonography. A total of 120 patients with small hepatocellular carcinoma (less than 3 cm in size) were examined. The definitive detection rate for primary tumors less than 2 cm in size was 44.9% by angiography, while it was 68.6% for primary tumors between 2 cm and 3 cm in size. When the primary tumor was less than 2 cm in size and without tumor vessels on angiography, it tended to be of Edmondson's grade 1 and to show fatty change. When the primary tumor was less than 2 cm in size and without tumor stain while non-cancerous parenchyma showed irregular stain, it tended to be of Edmondson's grade 1 and normotrabecular type. Angiography was found to be of particular value in detecting satellite tumors with a nodular parenchymal echo pattern in non-cancerous areas, because ultrasonography often fails to differentiate these satellite tumors from non-affected parenchyma.

Adult↗