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Biomedical subjects

K Komiyama

Publications and source records attributed to K Komiyama.

At least 37 records · Page 2Linked to original sources
PubMed1999

Clinicopathological studies of odontoma in 47 patients.

A 14-year retrospective study was performed on 47 odontomas from the files of the 1st Department of Oral and Maxillofacial Surgery at Nihon University School of Dentistry. Fifty-seven percent of the patients were male and 42.6% were female. The age distribution was 8 to 48 years with a mean age of 22 +/- 9.0 years. There were no particular symptoms associated with the odontomas, and 63.8% of our patients had no symptoms. However, 12 patients complained of swelling and 9 of pain. The tumor was found in the maxilla in 42.6% and in the mandible in 57.4%. According to the WHO histological type classification, 53.2% of the tumors were classified as compound odontoma and 46.8% as complex odontoma. The size of the tumor ranged from 5 mm to 42 mm in diameter. The average complex odontoma was much bigger than the average compound odontoma. Ghost cells were found 11 cases in our series. In addition, odontogenic epithelium was found in 16 cases. Twenty seven patients had impacted teeth in association with odontoma and 24 of the 27 teeth were removed at the time of surgical enucleation of the tumor, while 3 cases were treated by orthodontically assisted eruption. There was no recurrence in any of the studied cases.

Adolescent↗
PubMed1999

Predicting tumor metastasis in patients with oral cancer by means of the proliferation marker Ki67.

Recent developments of a Ki67 antibody to recombinant parts of the Ki67 nuclear antigen have provided a marker for tumor proliferation. In the present study, biopsy specimens were obtained from 20 patents with squamous cell carcinoma of the oral cavity at various sites, who also received a regional neck dissection. The patients' mean age was 61 years. Normal mucosa obtained from the surgical materials of 10 patients with a non-tumor condition was also examined as a control. The expression of Ki67 was examined immunohistochemically and the labeling index (LI) assessed in the biopsy specimens. The patients were divided into two groups; patient who already had a regional lymph node metastasis at the time of tumor resection and patient without any metastasis. All of the oral carcinoma and normal mucosa specimens were positive for Ki67, while the magnitude of staining showed a wide variation. The median LI of the patients with metastasis and without metastasis was 37.63 +/- 8.30 and 20.40 +/- 4.22 respectively, while the normal mucosa control was 7.62 +/- 1.70. The results of this study suggest that an immunohistochemical examination of the biopsy materials for the Ki67 antigen and assessed LI index should prove useful for the prediction of lymph node metastasis.

Adult↗
PubMed1998

Reversal of multidrug resistance (MDR) by aspidofractinine-type indole alkaloids.

A series of indole alkaloids of the aspidofractinine-type was assessed for their potential in reversing MDR in vincristine-resistant KB cells. Of the compounds tested, kopsiflorine, kopsamine, pleiocarpine, 11-methoxykopsilongine, lahadinine A and N-methoxycarbonyl-11,12-methylenedioxy-delta 16,17-kopsinine were found to show appreciable activity.

Alkaloids↗
PubMed1998

Cytotoxic and leishmanicidal aminoglycosteroids and aminosteroids from Holarrhena curtisii.

The EtOH extract of the leaves of Holarrhena curtisii yielded five new steroidal alkaloids: 17-epi-holacurtine (3), 17-epi-N-demethylholacurtine (4), holacurtinol (5), 3alpha-amino-14beta-hydroxypregnan-20-one (7), and 15alpha-hydroxyholamine (8), in addition to the known compounds, holacurtine (1), N-demethylholacurtine (2), and holamine (6). All eight compounds showed significant cytotoxic and leishmanicidal activities.

Alkaloids↗
PubMed1998

Distribution and synthesis of apolipoprotein J in the atherosclerotic aorta.

The distribution of apolipoprotein (apo) J during the development of atherosclerosis in the human aorta was evaluated by immununohistochemical observation, together with the other apolipoprotein A-I, A-II, B, C-III, and E. Although apoJ was never observed in the normal aorta (ie, without any intimal lesions or intimal thickening), it was distributed not only in the intima but also in the media of aortas with diffuse, intimal thickening or atherosclerotic lesions. Double immunostaining with antibodies for apoJ and alpha-smooth muscle actin revealed apoJ deposition in smooth muscle cells (SMCs) or the aortic stroma in the vicinity of SMCs. The extent of apoJ distribution in the aortic wall increased with the degree of atherosclerosis development. In addition, the distribution pattern of apoJ was very similar to that of apoA-I and E. In situ hybridization with human apoJ cDNA demonstrated intense signals in cells scattered within the subendothelial space and medial SMCs of the aorta with advanced atherosclerosis but not in those of the normal aorta without intimal thickening. Furthermore, reverse transcriptase-polymerase chain reaction of the cultured human aortic SMCs revealed apoJ mRNA expression in these cells. The results indicate that apoJ in the aortic wall originates from not only apoJ circulated in the plasma but also apoJ produced by SMCs in the aortic wall. Considering the similarities of the distribution between apoJ and apo-A-I or E, we hypothesize that apoJ possibly has a protective role against human atherosclerosis by its involvement with cholesterol transport from the aortic wall to the liver.

Adolescent↗
PubMed1998

Rapid diagnosis of oral tuberculosis by amplification of Mycobacterium DNA from paraffin embedded specimens.

The polymerase chain reaction (PCR) assay is a powerful tool for quick diagnosis of various infectious diseases. We applied this technique as well as conventional histopathological examination to diagnose oral tuberculosis. Ziehl-Neelsen staining of oral mucosal specimens often fails to detect Mycobacterium (M.) tuberculosis due to the low number of bacteria in the tissue. Specific primers and probes were synthesized based upon the nucleotide sequence of the 65 kDa membrane protein of M. tuberculosis. DNA extracted from the paraffin-embedded tissue was amplified using taq polymerase. PCR assay detected M. tuberculosis in 5 of 6 samples. Although the gene segments from these species were quite similar, the gamma 32P labeled noligonucleotide probes distinguished between M. tuberculosis and M. fotuitum by southern blot hybridization. In all specimens that were Ziehl-Neelsen negative, M. tuberculosis DNA was detected by PCR. These results suggest that PCR is a useful means of diagnosing mycobacterium infection.

Adult↗
PubMed1998

Enhancement of drug accumulation by andrastin A produced by Penicillium sp. FO-3929 in vincristine-resistant KB cells.

In the course of our screening for compounds that reverse multidrug resistance, we found that the cytotoxicity of vincristine was enhanced 1.5-20-fold depending on the concentration of andrastin A in vincristine-resistant KB cells (VJ-300). Andrastin A alone had no effect on the growth of drug sensitive KB cells and VJ-300 cells. On the other hand, andrastin A (25 and 50 micrograms/ml) significantly enhanced accumulation of [3H]vincristine in VJ-300 cells. Andrastin A (50 micrograms/ml) completely inhibited the binding of [3H]azidopine to the P-glycoprotein in VJ-300 cells. The result suggests that andrastin A directly interacts with P-glycoprotein and inhibits the efflux of antitumor agents in drug resistant cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

[Fundamental studies on antibacterial activity of clindamycin against Propionibacterium acnes].

Antibacterial activity of clindamycin against Propionibacterium acnes (P. acnes) was evaluated in comparison with nadifloxacin in vitro. Using a burned-infected mouse model, topical application of 1% gel form of clindamycin phosphate on P. acnes was also evaluated in in vivo. (1) The MIC of clindamycin measured by agar dilution method was 0.02 microgram/ml, and this value was smaller than that of nadifloxacin (0.3 microgram/ml). (2) At concentrations on 1-, 2- and 4- times the MIC clindamycin demonstrated bacteriostatic activity on P. acnes and showed bactericidal activity at 5-times the MIC. Nadifloxacin showed bacteriostatic activity at one half the MIC and bactericidal activity at the MIC. (3) Against acquired resistant strains of P. acnes, the highest concentrations of clindamycin and nadifloxacin that did not inhibit growth of the organism increased 5-fold higher than those against sensitive strain during 25 successive cultures in vitro. Therefore, the resistance of P. acnes was found to be emerged at almost the same ratio against both agents. (4) The chemotherapeutic effects of 1% gel form of clindamycin phosphate and 1% cream of nadifloxacin were evaluated for given subcutaneously to infected P. acnes at the burned site in mice. The topical application of either agents showed a significant reduction of number of bacteria and this result predicted clinical efficacy of topical application of clindamycin.

Administration, Topical↗
PubMed1997

Carbazole alkaloids from Murraya koenigii.

Two new alkaloids, 9-carbethoxy-3-methylcarbazole and 9-formyl-3-methylcarbazole, and a known metabolite, 3-methyl-carbazole were isolated from the roots of Murraya koenigii. All three compounds were identified by detailed spectral analyses including 2D NMR studies and their structures confirmed by synthesis. Of the two new metabolites, the 9-formyl compound displayed weak cytotoxicity against both mouse melanoma B16 and adriamycin-resistant P388 mouse leukemia cell lines.

Animals↗
PubMed1997

Intraoral minor salivary gland tumors: a retrospective study of 129 cases.

From 1970 to 1996, 129 cases of intraoral minor salivary gland tumors were diagnosed at the Department of Pathology, Nihon University School of Dentistry. The diagnosis of each case was based on the 1991 WHO classification. Eighty benign and 49 malignant minor salivary gland tumors were found in the approximately 9,300 oral biopsies submitted during the 27-year period. Pleomorphic adenomas were the most commonly histologic type of the benign tumors identified and 51% of the malignant tumors were diagnosed as mucoepidermoid carcinoma. The most common primary location of the tumors was the palate. Sixty percent of all tumors occurred in females and the peak age for incidences of all tumors was found in the third, fourth, sixth and seventh decades. These results were compared with those of the studies in different world population groups.

Adenoma, Pleomorphic↗
PubMed1997

A case of hemangiopericytoma of the buccal mucosa.

We report a 46-year-old woman who presented with a hemangiopericytoma in the buccal mucosa. At the 2-year postoperative examination, there was no evidence of recurrence or metastasis. The findings in the present case are compared with previous reports in the Japanese literature, with regard to patient age and sex, and lesion size, location, malignancy, local recurrence and metastasis.

Endothelium, Vascular↗
PubMed1997

Amphistin, a new melanogenesis inhibitor, produced by an actinomycete.

A new melanogenesis inhibitor, named amphistin, was isolated from the fermentation broth of an actinomycete strain KP-3052. Amphistin was purified from the culture filtrate by the combination of cation exchange, gel filtration, and aminosilyl silica gel chromatographic methods. The structure of amphistin was elucidated as gamma-(beta-histidinoalanino)homoalanine by NMR experiments including 1H-15N HMBC experiment and other spectroscopic analyses. Amphistin inhibited the melanogenesis of B16 melanoma cells at concentration of 6.8 microM.

Actinomycetaceae↗
PubMed1997

Pyridindolols K1 and K2, new alkaloids from Streptomyces sp. K93-0711.

Two new alkaloids with the beta-carboline skeleton, pyridindolols K1 (C18H18N2O5) and K2 (C16H16N2O4), were isolated from the culture both of Streptomyces sp. K93-0711. The structure of pyridindolols were established by spectroscopic investigations and chemical transformations. Pyridindolol K2 inhibited the adhesion of HL-60 cells to LPS-activated HUVEC monolayer (IC50 = 75 micrograms/ml).

Alkaloids↗