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Biomedical subjects

H Koga

Publications and source records attributed to H Koga.

At least 217 records · Page 12Linked to original sources
PubMed1994

A clinicopathologic study of small flat colorectal carcinoma.

BACKGROUND: Recent studies have noted that small flat carcinomas do exist in the human colon, but their clinicopathologic features have not been fully delineated. METHODS: A clinicopathologic study of 62 flat colorectal carcinomas (FCC) and 80 polypoid colorectal carcinomas (PCC) was performed. FCC were defined for the study as colorectal adenocarcinomas confined to the mucosa or submucosa, macroscopically characterized as slightly elevated, often nearly flat, and sometimes with central shallow depressions. RESULTS: In intramucosal and submucosal invasive carcinomas, the mean size of FCCs was significantly smaller than that of PCCs, (P < 0.001). When compared with PCCs, FCCs were found more often in the proximal colon, less frequently well differentiated, and had fewer adenomatous remnants. In submucosal invasive cases, FCCs showed more frequent deep invasion (67 versus 32%, P < 0.05) and lymphovascular permeation (41% versus 16%, P < 0.05) compared with PCCs. CONCLUSIONS: These results suggest that FCCs are characterized by frequent deep invasion with lymphovascular permeation even when small, and that they may be more prevalent away from the rectosigmoid area.

Adenocarcinoma↗
PubMed1994

Detection of Candida enolase antibody in patients with candidiasis.

The serodiagnostic value of candida enolase antibody was evaluated in 27 patients with systemic candidiasis. The glycolytic enzyme enolase was prepared from Candida albicans IFM 40009 and used as the antigen for immunoblot assays. IgG class antibody was found in the sera of 17 of 27 patients (62.9%) obtained during the early course of the infection. Serial sampling of sera increased the number of patients with positive Candida enolase antibody, which was detected in 25 of 27 patients (92.5%). None of the patients with localized candidiasis showed a positive IgG titer more than 1:100. The specificity of Candida enolase IgG antibody was 95%. This antibody was observed in various candida species: Candida albicans (6/7, 85.7%); C. parapsilosis (7/9, 77.9%); C. tropicalis (5/5, 100%); C. guilliermondii (4/4, 100%); and C. glabrata (1/3, 33.3%).

Adult↗
PubMed1994

Analysis of p53 gene mutations in low- and high-grade astrocytomas by polymerase chain reaction-assisted single-strand conformation polymorphism and immunohistochemistry.

Using polymerase chain reaction-assisted single-strand conformation polymorphism (PCR-SSCP) and immunohistochemical analyses, mutations in the p53 tumor suppressor gene were examined in 19 low- and high-grade gliomas. By PCR-SSCP and nucleotide analyses, p53 gene mutation was seen in 7 gliomas. Out of the 7 mutations, 3 were located at the CpG site of the previously proposed hot-spot codons 248 and 273, 2 were at codons 171 and 214 and the other 2 were in intron 5, 1 at the splice acceptor site and the other in the vicinity of the splice donor site. The latter 4 mutations have not, or only rarely, been observed in gliomas or in other tumors. However, their effect on the structural and functional alteration of the p53 protein was suggested by positive intranuclear p53 immunostaining in neoplastic cells in 3 mutations including the 1 at the splice acceptor site. In connection with glioma grading, the p53 gene mutation was shown to have occurred in both low- and high-grade gliomas, often in most of the neoplastic cells, as suggested by lack of distinct normal bands and ladders in SSCP and direct sequencing, respectively. The absence of recurrence and malignant transformation over a considerably long postoperative time in our low-grade glioma cases suggested that the p53 gene mutation might not be sufficient for the progression from low- to high-grade gliomas. The frequency of detection of mutation was 7/19(37%) by PCR-SSCP, 8/19(42%) by immunohistochemistry and 10/19(53%) by both methods. The results of PCR-SSCP and immunohistochemistry were consistent in 14 cases (73.7%), but not in 5 cases(26.3%).(ABSTRACT TRUNCATED AT 250 WORDS)

Astrocytoma↗
PubMed1994

The Eiken Latex test for detection of a cryptococcal antigen in cryptococcosis. Comparison with a monoclonal antibody-based latex agglutination test, Pastorex Cryptococcus.

A latex agglutination test for cryptococcal antigen, the Eiken Latex test (Eiken, Tokyo, Japan), was compared with a monoclonal antibody-based agglutination assay, Pastorex Cryptococcus (Diagnostics Pasteur, Marneur-la-Coquette, France). In a murine model of disseminated cryptococcosis, the kinetics of the antigen titers by the Eiken Latex were similar to those by the Pastorex Cryptococcus, but sensitivity was much higher. In HIV-negative patients with pulmonary cryptococcosis, a cryptococcal antigen was detected in 6 of 10 patients by the Eiken Latex test and in only 3 of those patients by the Pastorex Cryptococcus. The results indicate that the Eiken Latex is more sensitive for the detection of the cryptococcal antigen, even in non-disseminated cryptococcosis. The sensitivity and specificity of the Eiken Latex were examined using 195 sera from 25 patients with pulmonary cryptococcosis and 170 patients with non-cryptococcosis. The cutoff value of > or = 1:8 showed a sensitivity of 76% (19/25) and a specificity of 98.9% (168/170).

Agglutination Tests↗
PubMed1994

In vitro and in vivo antifungal activities of liposomal amphotericin B, and amphotericin B lipid complex.

The in vitro and in vivo antifungal activities of liposomal amphotericin B (L-AMPH) and amphotericin B lipid complex (ABLC), which is composed of amphotericin B and the phospholipids dimyristoyl phosphatidylcholine and dimyristoyl phosphatidylglycerol, were compared with those of conventional amphotericin B (Fungizone, AMPH). The acute intravenous toxicity was markedly lower in BALB/c mice; 50% lethal doses (LD50s) were 2.75 mg/kg in AMPH, 32.9 mg/kg in L-AMPH and > 75 mg/kg in ABLC. In vitro antifungal activities against Candida albicans, C. parapsilosis, C. tropicalis, C. glabrata, and C. krusei were evaluated by the agar plate dilution method. The activities were unchanged against C. albicans, but MICs increased more than four fold in 18 of the 20 strains other than C. albicans in L-AMPH and in 9 of the 20 in ABLC. L-AMPH and ABLC were as efficacious as AMPH in the treatment of mice infected with C. albicans, and at a dose of 0.5 and 1.0 mg/kg of body weight, ABLC was more efficacious on survival A ten-times larger dose (10 mg/kg) of L-AMPH and ABLC was administered to mice with 100% survival, suggesting improved tolerability as compared to amphotericin B.

Amphotericin B↗
PubMed1994

Nucleotide sequence of the gene encoding a repressor for the cytochrome P-450cam hydroxylase operon on the Pseudomonas putida CAM plasmid.

The camR gene of Pseudomonas putida encodes a repressor which regulates expression of the cytochrome P-450cam hydroxylase operon (camDCAB). We determined the nucleotide sequence of 1134 continuous base pairs, including the camR gene. When comparing the amino acid sequence deduced from the open reading frame of the gene sequence with that of amino-terminal five residues of the cam repressor, purified from Pseudomonas putida, we found that the camR gene encodes a protein of 186 amino acids, with a molecular mass of 20.4 kDa. The start codon for the cam repressor is the rare initiation codon GTG. The cam repressor predicted from the camR sequence contained a region similar to that seen in other DNA-binding proteins.

Amino Acid Sequence↗
PubMed1994

Construction and expression of chimeric antibodies by a simple replacement of heavy and light chain V genes into a single cassette vector.

A novel vector pMH-gpt, which is proved useful for cloning mouse immunoglobulin heavy and light chain V genes and for expressing mouse-human chimeric antibody, was constructed. The vector contains human genomic C gamma 1 and C kappa genes, cloning sites for immunoglobulin V region genes, murine Ig promoters, a human Ig heavy chain enhancer, and the selection marker gene Eco-gpt. Because VH and V kappa genes can be cloned into a single vector, a chimeric antibody gene is easily constructed by this simple insertion procedure. The usefulness of the vector was confirmed by construction of two mouse-human chimeric antibodies. Mouse monoclonal antibody (MAb) 196-14 recognizes the ovarian cancer-associated antigen (CA125), and MoAb 2-18 reacts with carcinoembryonic antigen (CEA). Mouse-human chimeric 196-14 and 2-18 antibodies were readily constructed and efficiently produced in a mouse myeloma cell line by utilizing the vector. Both chimeric antibodies retained binding activity to their respective antigens. In biodistribution and immunoscintigraphy studies, specificity of radiolabeled chimeric 196-14 antibody was identical to that of its murine counterpart and significant accumulation at the tumor site was observed. The pMH-gpt vector is useful for constructing and producing mouse-human chimeric antibodies.

Amino Acid Sequence↗
PubMed1994

Case report: Wegener's granulomatosis accompanied by communicating hydrocephalus.

A case of Wegener's granulomatosis (WG) accompanied by communicating hydrocephalus is described. An elderly woman with rapidly progressive renal failure was referred to the authors' hospital. Renal histologic study showed necrotizing granulomatous glomerulonephritis with some multinucleated giant cells, which suggested a diagnosis of WG. After admission, a gait disturbance, incontinence, and dementia developed in the patient. Diagnostic procedures including lumbar puncture, computed tomography (CT), and scintigraphy showed findings compatible with communicating hydrocephalus with a normal cerebrospinal fluid (CSF) pressure. Removal of 20 mL of CSF led to a marked improvement in symptoms. Because the presence of subarachnoid hemorrhage, meningitis, and brain tumor was excluded, the final diagnosis was communicating hydrocephalus secondary to WG.

Aged↗
PubMed1994

Influence of molecular sizes of Cryptococcus neoformans capsular polysaccharide on phagocytosis.

The role of capsular polysaccharides (CPS) of Cryptococcus neoformans in phagocytosis by murine alveolar macrophages was investigated in four strains of C. neoformans serotype A, YC-11, YC-5, YC-27 and YC-13. Phagocytosis rates increased markedly after adding 10% mouse serum, compared to fetal calf serum. The reverse relation between capsular thickness of C. neoformans and phagocytosis by alveolar macrophages was observed except in YC-27, which had thin capsules and high virulence. The phagocytosis rate in mice serum was 17.3% in YC-11 (capsule thickness 2.8-3.5 microns), 39.8% in YC-5 (capsule size 0.8-1.5 microns), 20.3% in YC-27 (capsule size 0.6-1.1 microns), and 62.8% in YC-13 (capsule not detected microscopically). The CPS of YC-11, YC-5, and YC-27 analyzed by gel-filtration using CL-2B showed high molecular fractions near the void volume. However, the CPS of YC-13 showed only low molecular fractions. The widely eluted CPS of YC-11 was separated into 3 fractions and each fraction was added in the phagocytosis assay of YC-13. Phagocytosis was markedly suppressed particularly by the addition of a higher molecular fraction. These results suggest that phagocytosis of C. neoformans by alveolar macrophages is influenced by the molecular sizes of the CPS.

Animals↗
PubMed1994

[Three cases of Pasteurella multocida infection in the respiratory tract].

Pasteurella multocida (P. multocida) is well recognized as "normal flora" in the upper respiratory tract of cats, dogs and other animals. Recently, various infections due to P. multocida in human have been noted as pulmonary infections in the patients with chronic pulmonary diseases as well as skin abscesses or septicemia after an animal bite or scratch. We report here three cases of respiratory tract infections caused by P. multocida. The first two patients had acute exacerbation of bronchiectasis caused by P. multocida and the other patients with pulmonary emphysema developed pneumonia. These three patients improved by antibiotic therapy. In Japan, P. multocida respiratory tract infection is rare, but it may become more common in the future. Therefore, it seems to be important to take this pathogen into consideration in the management of chronic lung disease.

Adult↗
PubMed1994

[A case of brain abscess associated with enterococcal endocarditis].

Enterococcal infections involving the central nervous system are uncommon clinical entities. A 74-year-old male was admitted to our hospital on November 3, 1991 for high fever. Nuchal rigidity was observed at neurological examination. All four blood cultures yielded E. faecalis. The MIC value of ABPC against the isolated E. faecalis was 0.25 microgram/ml. Vegetation on the mitral valve and mitral regurgitation were revealed by an echocardiogram. Enhanced CT scan showed low density area with ring enhancement in the right basal ganglia and a CSF examination suggested bacterial meningitis. He became better after ABPC 8 g/day was intravenously administered. Then the vegetation on the mitral valve and the brain abscess disappeared. He was discharged with no complications. We reported a rare case of brain abscess associated with enterococcal endocarditis.

Aged↗
PubMed1994

[Anaerobic respiratory infection--evaluation of methods of obtaining specimens].

Anaerobic cultures were performed on various kinds of specimens obtained from 67 patients with respiratory infections. The infections consisted of 33 cases of pneumonia, 14 cases of lung abscess, 6 cases of pyothorax, 9 cases of chronic lower respiratory tract infection, and 5 cases of infection of pulmonary cyst. Specimens included bronchoscopic specimens obtained using a single tube or protected catheter brush (PCB), transtracheal aspirate, percutaneous lung aspirate, aspirate using a suction tube through the tracheostomy or intubation tube, and pleural fluid. Anaerobes were isolated in 80% of pyothorax, 43% of lung abscess, and 15% of pneumonia (42% of aspiration pneumonia), respectively. Anaerobes isolated frequently in respiratory infections included Prevotella spp., Fusobacterium spp., and Peptostreptococcus spp. In regard to the type of specimen, bronchial aspirate obtained by bronchoscopy was useful in examination of pneumonia, and was useful as percutaneous lung aspirate in examination of lung abscess. But there was discrepancy of culture results between specimens obtained by different methods in the same patient. To confirm anaerobes as pathogens in respiratory infections, it is necessary to select an appropriate method to obtain specimens and to interpret the culture results comprehensively.

Adult↗
PubMed1994

[Clinical investigation of obstructive pneumonia with lung cancer].

Nineteen episodes (18 patients) of obstructive pneumonia occurring in 247 patients with lung cancer were clinically examined, and the following findings were obtained. 1) All 18 patients were male smokers, with an average of 64 years. 2) Body temperatures stood above 37 degrees C in 95% of the 19 episodes. Leukocytosis was detected in 41%, and neutrophilia was observed in 69%. CRP values were positive in all episodes. 3) The frequency of obstructive pneumonia according to the site of lung cancer was 13.2% in proximal tumors and 1.7% in peripheral tumors. Pathologically, the frequency was 5.2% in adenocarcinomas 7.6% in squamous cell carcinomas, 15.6% in small cell carcinomas and 9.1% in large cell carcinomas. Squamous cell carcinomas even in Stage I led to obstructive pneumonia at the rate of 13.0%. In contrast, higher frequency was observed in adenocarcinomas in Stage II or later and small cell carcinomas in Stage IIIB or later. 4) Obstructive pneumonia was detected at the time of discovery of lung cancer in 48% of the 18 patients, and during treatment and in the terminal stage in 26% respectively. 5) Chest X-ray examinations showed that 42% of the pneumonia cases were lobar pneumonia and 11% had pleural effusion. 6) In expectorated sputum, 50% of bacteria isolated were gram-negative, 10% were gram-positive and 40% were unknown. 7) Most of the bacteria isolated from expectorated sputum showed a good susceptibility to antimicrobial agents, but those proved clinically ineffective. 8) The prognosis of obstructive pneumonia was significantly affected by performance status and levels of total protein and choline-esterase.

Aged↗
PubMed1994

Effects of antifungal agent combinations administered simultaneously and sequentially against Aspergillus fumigatus.

The in vitro effects of antifungal agent combinations administered simultaneously and sequentially against 15 strains of Aspergillus fumigatus were tested by the yeast-malt broth method. The synergistic effect of the combination of amphotericin B (AMPH) and miconazole was observed in nine strains (60%). However, the combinations of AMPH and fluconazole, AMPH and ketoconazole, and AMPH and itraconazole administered simultaneously showed antagonistic effects against three (20%), five (34%), and four (26%) strains, respectively. The effects of combinations of azole antifungal agents administered simultaneously were indifferent or antagonistic against A. fumigatus. In experiments measuring the effects of sequentially administered antifungal agents, however, pretreatment with AMPH and then azole antifungal agents exhibited better in vitro efficacy than that found in experiments measuring the effects of simultaneously administered AMPH and azole compounds.

Antifungal Agents↗
PubMed1994

Comparative in vitro exoenzyme-suppressing activities of azithromycin and other macrolide antibiotics against Pseudomonas aeruginosa.

The inhibitory effects of azithromycin (AZM), a new 15-membered macrolide antibiotic, on the production of exotoxin A, total protease, elastase, and phospholipase C by Pseudomonas aeruginosa were determined, and the virulence-suppressing effects of AZM were compared with those of erythromycin (EM), roxithromycin (RXM), and rokitamycin (RKM). The effect of exposure of P. aeruginosa PA103 or B16 in cultures to sub-MICs of these macrolide antibiotics on the production of exoenzymes was determined. AZM suppressed the in vitro production of extracellular and intracellular exotoxin A by P. aeruginosa PA103 more than did EM, even at a concentration of only 2 micrograms/ml. At concentrations of between 4 and 32 micrograms/ml, AZM also inhibited total protease, elastase, and phospholipase C production by P. aeruginosa B16 more than did EM, RXM, and RKM. AZM was effective in suppressing exotoxin A and total protease production through 24 h of incubation in the presence of drug at sub-MICs, but it had no significant effect on either the growth of P. aeruginosa or its total protein production. Moreover, at a concentration of 4 micrograms/ml, AZM suppressed exoenzyme production by other strains of P. aeruginosa more than did EM. These findings indicate that AZM, EM, RXM, and RKM each has an inhibitory effect on exoenzyme production separate from the antimicrobial effect and that, of these macrolides, AZM has the strongest virulence-suppressing effect.

ADP Ribose Transferases↗
PubMed1994

Pneumonia caused by Stenotrophomonas maltophilia with a mucoid phenotype.

We describe the first known case of pneumonia caused by a mucoid Stenotrophomonas maltophilia (Xanthomonas maltophilia) strain in a patient with bronchiectasis. The patient was admitted because of mild hemoptysis and productive cough with infiltrative shadow in the right lower lung field on chest X ray. The clinical symptoms were mild, and treatment with minocycline was effective.

Female↗
PubMed1994

Detection of Bacteroides fragilis in clinical specimens by PCR.

The direct detection of Bacteroides fragilis from clinical specimens was examined by using the PCR method for amplifying a specific fragment of the glutamine synthetase gene from B. fragilis. By this method, all five B. fragilis strains tested were detected, but DNAs from anaerobic bacteria of 24 other species tested, from aerobic bacteria of 12 species tested, and from human leukocytes were not amplified. Using the nested PCR method, we were able to detect as little as one bacterial cell or 100 fg of chromosomal DNA of B. fragilis. A total of 39 clinical specimens, which consisted of 19 bronchial aspirates, 10 percutaneous lung aspirates, 2 transtracheal aspirates, 6 pleural fluid specimens, and 2 pus specimens, were tested. All four culture-positive samples, of which two were bronchial aspirates, one was pleural fluid, and one was pus, were positive by PCR. Among 35 culture-negative samples, 2 bronchial aspirates were positive by PCR. One was from a patient whose two previous samples were positive by both culture and PCR. It had been submitted for culture several hours after collection, and clindamycin had been administered to the patient before collection of the specimen. The other bronchial aspirate positive by PCR was from a pneumonia patient who had also been administered clindamycin. We believe that B. fragilis was present in these two specimens but that either it was dead, it was below the level detectable by culture, or the process of anaerobic culture was unsuccessful. Thus, the PCR method may be considered useful for the sensitive and rapid detection of anaerobes in clinical specimens.

Bacteroides Infections↗