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Biomedical subjects

M Honma

Publications and source records attributed to M Honma.

At least 55 records · Page 3Linked to original sources
PubMed1999

Tunnel capillaries of cardiac myocyte in pressure-overloaded rat heart-an ultrastructural three-dimensional study.

To characterize the configuration of "tunnel capillaries" in myocytes, an ultrastructural three-dimensional (3-D) study was performed on pressure-overloaded rat hearts induced by 16-week constriction of the ascending aorta. The hearts showed high incidence (6.1 +/- 3.6%) of tunnel capillary formation. Eighty-two myocytes (26.4%) had tunnel capillaries in a cubic block of 120 x 656 x 446 micron3, which provided 1000 ultrathin serial sections. The cross-sectional area (925 +/- 226 micron2) of myocytes with tunnel capillaries was significantly larger than that of myocytes without tunnel capillaries (702 +/- 196 micron2) (P < 0.0001). There were three types of tunnel capillaries. Type I (13%) started from one intercellular capillary, ran across the myocyte, and then merged with other intercellular capillaries. Type II tunnel capillaries (87%) entered the myocyte from one intercellular capillary and ended within the myocyte. Type III tunnel capillaries were characterized by various combination of types I and II, forming a tunnel capillary network. Tunnel capillaries usually entered a myocyte at the place where the myocyte split or indented. Although some tunnel capillaries might be newly formed by angiogenesis, our 3-D study suggests that some of them are a deformation consequence of the myocardium remodeling in response to pressure overloading.

Animals↗
PubMed1999

The need for long-term treatment in the mouse lymphoma assay.

The L5178Y tk +/- mouse lymphoma assay (MLA) has been widely used as a genotoxicity test for the detection of mutagens and clastogens. The standard MLA, as well as other mammalian cell gene mutation assays, usually employs a short treatment period (3-6 h). Our previous report, however, suggested that such short treatments may be insufficient for detecting some clastogens and spindle poisons. For the present study, we introduced and evaluated a longer treatment (24 h) in the MLA. We examined 15 chemicals which were evaluated as negative or inconclusive in the short-term study. Cells were exposed to the chemical for 24 h without S9 mix, cultured for 2 days and then thymidine kinase-deficient mutants were selected in 96-well microtiter plates under trifluorothymidine. Eleven chemicals yielded positive responses in the 24 h treatment MLA. They included nucleoside analogs (2'-deoxycoformycin and dideoxycytidine), a base analog (1,3-dimethylxanthine) and spindle poisons (colchicine and vinblastine sulfate), all of which do not directly affect DNA, but bring about mutations and chromosome alterations through nucleoside metabolism and chromosome segregation. Because the mutagenicities of these non-DNA targeting chemicals appear to be cell cycle dependent, treatment extending over more than one cell cycle may be required for their effect. Combining results from the present and previous studies, 31 of 34 (91%) chromosome aberration-positive chemicals exhibited positive responses in the MLA, suggesting that the sensitivity of the MLA with 24 h treatment periods approaches that of the chromosome aberration test.

Animals↗
PubMed1999

Evaluation of the mouse lymphoma tk assay (microwell method) as an alternative to the in vitro chromosomal aberration test.

In order to evaluate the utility of the mouse lymphoma assay (MLA) for detecting in vitro clastogens and spindle poisons and to compare it with the in vitro chromosomal aberration test (CA), we conducted an international collaborative study of the MLA that included 45 Japanese laboratories and seven overseas laboratories under the cooperation of the Ministry of Health and Welfare of Japan and the Japanese Pharmaceutical Manufacturer's Association. We examined 40 chemicals; 33 were reportedly positive in the CA but negative in the bacterial reverse mutation assay, six were negative in both assays and one was positive in both. We assayed mutations of the thymidine kinase (TK) locus (tk) of L5178Y tk +/- mouse lymphoma cells using the microwell method. According to our standard protocol, cells were exposed to the chemical for 3 h, cultured for 2 days and TK-deficient mutants were expressed in 96-well plates under trifluorothymidine. Each chemical was coded and tested by two or three laboratories. Among the 34 CA-positive chemicals, positive MLA results were obtained for 20 and negative results were obtained for nine. The remaining five chemicals were inconclusive or equivocal because of discrepant inter-laboratory results or reproduced discrepant results, respectively. Among the six CA-negative chemicals, one was negative in the MLA, two were positive and three were inconclusive. Thus, the MLA could detect only 59% (20/34) of CA-positive chemicals. We concluded that the MLA was not as sensitive as the CA. Some MLA-negative chemicals evoked positive responses in the CA only after long continuous treatment. These might also be genotoxic in the MLA with long continuous treatment. Improvement of the MLA protocol, including alteration of the duration of the treatment, might render the MLA as sensitive as the CA.

Animals↗
PubMed1999

Purification and properties of extracellular carboxyl proteases of acid-tolerant bacteria, isolated from compost.

Four strains of acid-tolerant and protein-using bacteria were isolated from compost. Two of them, Gram-negative strains MB8 and MB11, were identified as a new genus close to Stenotrophomonas species MB8 and Burkholderia species MB11, respectively. Both bacteria produced extracellular carboxyl proteases (CP) in acid-casein-starch medium. The enzymes, termed CP MB8 and CP MB11, purified through ion exchange and gel filtration chromatographies had molecular weights of 61,000 (CP MB8) and 36,000 (CP MB11) as estimated by SDS-PAGE, and showed optimum activities with hemoglobin as a substrate at pH 3.5 (CP MB8) and pH 3.7 (CP MB11) at 55 degrees C. Both of the enzymes were not inhibited by pepstatin, DAN, or EPNP. These results suggest that both enzymes are members of the pepstatin-insensitive carboxyl proteinase family (EC 3.4.23.33), except for a larger molecular weight of the CP MB8 enzyme.

Amino Acid Sequence↗
PubMed1999

Synthesis and degradation of 1-aminocyclopropane-1-carboxylic acid by Penicillium citrinum.

1-Aminocyclopropane-1-carboxylic acid (ACC), which is a precursor of ethylene in plants, has never been known to occur in microorganisms. We describe the synthesis of ACC by Penicillium citrinum, purification of ACC synthase [EC 4.4.1.14] and ACC deaminase [EC 4.1.99.4], and their properties. Analyses of P. citrinum culture showed occurrence of ACC in the culture broth and in the cell extract. ACC synthase was purified from cells grown in a medium containing 0.05% L-methionine and ACC deaminase was done from cells incubated in a medium containing 1% 2-aminoisobutyrate. The purified ACC synthase, with a specific activity of 327 milliunit/mg protein, showed a single band of M(r) 48,000 in SDS-polyacrylamide gel electrophoresis. The molecular mass of the native enzyme by gel filtration was 96,000 Da. The ACC synthase had the Km for S-adenosyl-L-methionine of 1.74 mM and kcat of 0.56 s-1 per monomer. The purified ACC deaminase, with a specific activity of 4.7 unit/mg protein, showed one band in SDS-polyacrylamide gel electrophoresis of M(r) 41,000. The molecular mass of the native ACC deaminase was 68,000 Da by gel filtration. The enzyme had a Km for ACC of 4.8 mM and kcat of 3.52 s-1. The presence of 7 mM Cu2+ in alkaline buffer solution was effective for increasing the stability of the ACC deaminase in the process of purification.

Amino Acids↗
PubMed1999

[An old man presenting with fluctuating bilateral multiple cranial nerve palsies and positive test for perinuclear antineutrophil cytoplasmic antibody].

A 70-year-old man admitted to a local hospital because of facial muscle weakness, tinnitus and facial pain in left side, was then given corticosteroid with a tentative diagnosis of Bell's palsy and his symptoms gradually improved. Since these symptoms recurred six months later, he was referred to our neurological service. As his brain CT revealed diffuse thickening and enhancement of the dura mater, he was thought to have hypertrophic pachymeningitis (HP). Intravenous antibiotics were started for aspiration pneumonia and his neurological symptoms gradually improved. HP caused by bacterial infection was thus likely and antibiotics, rifampicin and metronidazole, were administered orally as an outpatient. However, one month later, these symptoms were worsened with headache and double vision. He was then rehospitalized. MR imagings of the head with gadolinium disclosed diffuse meningeal thickening and enhancement, especially of the left-sided cerebellar tentorium. Erythrocyte sedimentation rate and C-reactive protein were moderately elevated. Serum angiotensin converting enzyme was within normal range. The test for cytoplasmic antineutrohil cytoplasmic antibody (ANCA) in the serum was negative, however, that for perinuclear ANCA was positive at a titer of 99 EU. Lumbar puncture showed normal findings and negative culture results for bacteria, fungi or mycobacteria. Dural biopsy specimens showed non-specific granulomatous inflammation of the dura with epithelioid histiocytes and Langerhans type multinuclear giant cells with caseous necrosis, however, with no presence of fungi or tubercle bacilli. After the oral administration of cyclophosphamide (100 mg, daily) and prednisolone (40 mg, daily), his neurological symptoms and laboratory findings have been gradually improved and he is well one year after discharge. This case together with previous reports suggests that ANCA positive HP without evidence of other organ involvements may belong to the limited form Wegener's granulomatosis. In the literatures of idiopathic HP, the treatment effect with corticosteroid alone is initially favorable, but transient. On the other hand, using the combined therapy of cyclophosphamide and prednisolone, the remission has been achieved in more than 90% of patients with WG. These data suggest that P-ANCA positive HP should be treated with a combination of corticosteroid and cyclophosphamide.

Aged↗
PubMed1998

Enzymatic activity and partial purification of solanapyrone synthase: first enzyme catalyzing Diels-Alder reaction.

In cell-free extracts of Alternaria solani, an enzymatic activity converting prosolanapyrone II to solanapyrones A and D via oxidation and subsequent Diels-Alder reaction has been found. Chromatography with DEAE-Sepharose provided two active fractions, pools 1 and 2. The former fraction converted prosolanapyrone II to solanapyrones A and D in a ratio of 2.2:1 with optical purities of 99% and 45% ee, respectively. The latter fraction did so in a ratio of 7.6:1 with 99% and nearly 0% ee, respectively. The enzyme partially purified from pool 2 native molecular weight of 40-62 kD and a pl of 4.25. The high reactivity of prosolanapyrone III in aqueous solution and the chromatographic behavior of the enzyme in pool 2 suggest that a single enzyme catalyzes both the oxidation and Diels-Alder reaction.

Alcohol Oxidoreductases↗
PubMed1998

Specific mutational spectrum of dimethylnitrosamine in the lacI transgene of Big Blue C57BL/6 mice.

Dimethylnitrosamine (DMN) produces tumors in mice predominantly in the liver, but also in the kidney and lung. It forms O6-methylguanine adducts in DNA, which induce G:C-->A:T transitions. We have analyzed the spectra of spontaneous and DMN-induced mutations in the lacI transgene of the Big Blue mouse (C57BL/6). In both cases, mutations in the liver, kidney and lung were predominantly base substitutions, among which G:C-->A:T transitions were the most frequent. In contrast, a high incidence of short deletions (2-23 bp) was only found in the liver of treated mice. The deletions often occurred at direct repeat sequences. Single-base deletion incidence was also higher in the liver than in the kidney and lung. These results imply that accumulation of DNA lesions or their repair in liver is different from other organs. Spontaneous and induced base substitutions and deletions appeared to be randomly distributed in the lacI gene and an apparent hotspot was not observed, except for a 4 bp deletion of a (TGGC)3 sequence at positions 621-632. The present data demonstrate, for the first time, that DMN induces short deletions especially in the liver, although the mechanism involved needs further investigation.

Animals↗
PubMed1998

Properties, sequence, and synthesis in Escherichia coli of 1-aminocyclopropane-1-carboxylate deaminase from Hansenula saturnus.

The plant hormone ethylene is generated from a unique precursor, 1-aminocyclopropane-1-carboxylate (ACC). In previous studies, ACC deaminase, which degrades ACC to alpha-ketobutyrate and ammonia, was found in four strains of Pseudomonas, characterized, and sequenced. To verify the wider distribution of ACC deaminase in microorganisms, we purified and sequenced ACC deaminase from the yeast Hansenula saturnus. The purified enzyme was active toward ACC, D-serine and dl-coronamic acid, indicating the same stereospecificity as the Pseudomonas enzyme, but unlike the bacterial enzyme it was not active toward beta-chloro-D-alanine and O-acetyl-D-serine. Analyses of peptides from proteolytic digests of the purified and modified ACC deaminase covered more than 90% of its amino acid sequence and showed a blocked N-terminal residue as N-acetylserine. A cDNA encoding the ACC deaminase was isolated from H. saturnus cells incubated in alpha-aminoisobutyrate medium, and sequenced. The yeast enzyme has 441 amino acid residues, of which 60 to 63% are identical to those of reported Pseudomonas enzymes. The open reading frame encoding ACC deaminase was subcloned into pET-11d and expressed in Escherichia coli BL21 (DE3) as an active enzyme.

Amino Acid Sequence↗
PubMed1998

New diagnostic peritoneal lavage criteria for diagnosis of intestinal injury.

BACKGROUND: Although diagnostic peritoneal lavage (DPL) is a well-established, reliably objective method of diagnosis of intraperitoneal injury, it is too sensitive to be used as an indicator for emergency celiotomy. Therefore, since the development of ultrasonography and advanced computed tomographic scanners, the role of DPL has been markedly reduced. Despite such remarkable advances, however, radiologic diagnosis of intestinal injury cannot always provide definitive results, and DPL may still be valuable in such instances. We have developed a new DPL criteria specifically designed to aid in the diagnosis of intestinal injury and have evaluated its effectiveness. METHODS: From August 1988 to December 1995, we performed DPL in 250 patients with blunt abdominal trauma and analyzed the diagnostic accuracy of our new criteria. We used the standard quantitative white blood cell (WBC) criterion for detection of intestinal injury supplemented by a positive-negative borderline adjusted to WBC > or = red blood cell (RBC)/150, where RBC > or = 10 x 10(4)/mm3. RESULTS: Our criteria had a diagnostic sensitivity of 96.6% and a specificity of 99.4% for intestinal injury after exclusion of 57 patients in whom DPL was performed within 3 hours or after 18 hours from the time of injury. In 133 patients with hemoperitoneum, emergency celiotomy was performed in only 48; the remaining 85 patients with negative DPL based on the WBC criterion avoided surgery, and conservative management resulted in no complications. CONCLUSION: With the proposed criteria, DPL can be used to diagnose or exclude intestinal injury even in the presence of hemoperitoneum.

Abdominal Injuries↗
PubMed1998

Cutaneous allergic vasculitis: clinicopathological characterization and identification of apoptosis.

To elucidate the clinicopathological features of cutaneous allergic (leukocytoclastic) vasculitis (CAV), biopsied skin tissues of 32 patients with CAV were examined immunohistopathologically and compared with the main clinical features. Additionally, to obtain some clues to better understand the roles of infiltrating cells, particularly neutrophils in CAV, apoptosis and related antigens were investigated in vivo. The 32 patients with CAV were divided into two groups based on their clinical course: (i) non-recurrent (group I; nine cases); and (ii) recurrent (group II; 23 cases). Immunohistopathologically, group I was characterized by stereotypical necrotizing changes of CAV with fibrin exudation of small blood vessels in the upper cutis, and group II was characterized by CAV and fibrous thickening of the vascular walls with significant infiltration of CD3+, UCHL-1+ T cells. Group II was subdivided further: groups IIa (15 cases) and IIb (eight cases); that is, the former was notable for necrotizing changes of CAV, which tended to spread into the proper corium down to the lower cutis; whereas the latter exhibited considerably less marked histological changes of CAV without any spread to the lower cutis. In a comparison of the clinical data among the three groups, there were considerable differences in age, clinical course, localization of purpura and associated disease. In particular, group II showed a high frequency of connective tissue diseases. The presence of apoptosis was seen in a considerable number of neutrophils, and some nuclear debris turned out to be apoptotic bodies by the in situ terminal deoxytransferase (TdT)-catalyzed DNA nick end-labeling (TUNEL) method and electron microscopy. By combining immunohistochemistry with TUNEL, the majority of apoptotic neutrophils and nuclear debris was seen to be ingested by macrophages. In immunohistochemical examinations for apoptosis-related bcl-2 protein and Fas antigen, bcl-2 was recognized only in the cytoplasm of infiltrating T cells, and Fas was positively stained on the cellular membranes of infiltrating T cells and neutrophils in a scattered fashion. Thus, a novel method for neutrophil disposal in CAV was suggested.

Adult↗
PubMed1998

Localization of mRNA for inflammatory cytokines in radicular cyst tissue by in situ hybridization, and induction of inflammatory cytokines by human gingival fibroblasts in response to radicular cyst contents.

The expression of mRNA encoding the inflammatory cytokines interleukin-1alpha (IL-1alpha), interleukin-1beta (IL-1beta), interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor alpha(TNF-alpha) have been examined in radicular cysts by in situ hybridization. Furthermore, the biological activity of the contents of radicular cysts (RCC) has been assayed by adding extracts of RCC to cultured human gingival fibroblasts (HGFs) and analyzing the culture medium for the release of inflammatory cytokines. In the epithelial layer, keratinocytes expressed all cytokine mRNAs examined at various levels. Basal layer cells expressed mRNA for each cytokine. In the subepithelial granulation tissue of the cysts, fibroblasts and macrophages expressed mRNA for IL-6, IL-8, IL-1beta and TNF-alpha mRNA at varying levels; especially clear expression of TNF-alpha and IL-1beta mRNA was detected on macrophages. The infiltrating lymphoid cells, largely composed of T cells and plasma cells, expressed these cytokine mRNAs, especially those encoding IL-6 and IL-8, at various levels. In vitro analysis indicated dose-dependent release of both IL-6 and IL-8 by HGFs in response to RCC. After heating to 100 degrees C for 10 min, RCC almost completely failed to stimulate IL-6 release from HGFs. Furthermore, anti-IL-1beta antibody (neutralization test) did not prevent the stimulation of IL-6 release by RCC. Significant amounts of IL-6 and IL-8 were detected in RCC in two cases, and a trace amount of IL-1beta was detected in one case. This study demonstrated the wide expression of mRNA encoding inflammatory cytokines in radicular cyst tissues, and RCC itself was capable of stimulating IL-6 and IL-8 production from HGFs.

Antibodies↗
PubMed1998

Idiopathic sclerosing inflammation of the upper eyelid.

Idiopathic sclerosing inflammation has commonly been found in the diffuse orbital tissues. We report the inflammation of the right upper eyelid in a 65-year-old man. Computed tomography and magnetic resonance imaging showed a diffuse mass localized only in the right upper eyelid. Histologic study of the excised specimen revealed dense collagenous tissue with sparse infiltration of mixed inflammatory cells. Immunohistochemical study showed that the inflammatory cells were largely composed of T cells (UCHL-1), histiocytes (PG-M1) and scattered plasma cells (immunoglobulins). No L26-positive B cells were found. We believe that idiopathic sclerosing inflammation of the upper eyelid, as demonstrated in our patient, may be rare.

Aged↗
PubMed1998

Selective induction of interleukin-1 production and tumor killing activity of macrophages through apoptosis by the inhibition of oxidative respiration.

Suppression of mitochondrial respiration and increased glycolysis are characteristic features of activated macrophages. We show here that antimycin A, a respiratory inhibitor, induced interleukin-1 synthesis and tumoricidal activity without inducing tumor necrosis factor or nitric oxide. The induction of tumoricidal activity was resistant to inhibitors of tyrosine-specific protein kinases and intracellular glycoprotein transport. The cognate interaction between macrophages and target cells was not a prerequisite for the tumoricidal activity. In contrast, lipopolysaccharide induced the production of interleukin-1, tumor necrosis factor and nitric oxide, the induction of tumoricidal activity being sensitive to genistein and brefeldin A. Antimycin A, like lipopolysaccharide, induced the release of a cytoplasmic enzyme and apoptosis of macrophages. Antimycin A showed anti-metastatic activity in vivo. These results suggest that the inhibition of oxidative respiration would induce apoptosis and the resultant release of soluble effector molecules of macrophages which inhibit tumor metastasis in vivo.

Animals↗
PubMed1998

[A case of pulmonary infection with mycobacterium xenopi].

A 42-year-old man with pulmonary disease caused by Mcobacterium xenopi is described. He had a history of alcohol use of over 20 years. He was admitted to another hospital for evaluation of an abnormal chest shadow. A chest X-ray showed a cavitary shadow with infiltration in the right upper lung field. Acid-fast organisms were recognized in sputum and M. xenopi was identified by DNA-DNA hybridization. Although he had been treated with isoniazid, rifampicin, and ethanbutol for 5 years, sputum remained positive on culture and chest X-ray findings did not improve. He was later admitted to our hospital for surgery, and right upper lobectomy was performed. He has remained well for 18 months since the operation. In Japan, cases of the pulmonary infection with M. xenopi are rare. Surgical resection is required when chemotherapy is unsuccessful.

Adult↗
PubMed1998

[A 63-year-old man with progressive cauda equina/conus medullaris syndrome].

A 63-year-old man, whose father died of malignant lymphoma, developed subacutely cauda equina/conus medullaris syndrome progressed over 3 months. Initial radicular pain, ascending motor and sensory paralysis without sacral sparing, vesicorectal dysfunction were similar with signs of spinal dural arteriovenous fistula. However, mild inflammatory signs, raised serum LDH, predominantly of LDH 3, lymphocytic pleocytosis and elevated beta 2 microglobulin in CSF suggested neurolymphomatosis. It was not supported, however, after CSF immunocytochemistry, myelogram, CT, Gd-MRI and Ga scan. Spinal cord/nerve root vascular syndromes of intravascular lymphomatosis (IVL) according to Glass J et al. was suspected because of the unique neurological progression similar to Foix-Alajouanine syndrome, hypoxia without abnormalities in chest X-ray film, response to steroids and raised serum soluble IL-2 receptor. Multiple biopsies were performed with negative results. However, after all muscle biopsy confirmed IVL. The lower spinal irradiation was not effective. But CHOP regimen supplemented by granulocyte colony-stimulating factor (G-CSF) brought about swift neurological improvement and protection from late complications. Self-limiting polyneuropathy emerged during the biweekly CHOP therapy, 6 courses for 12 weeks. Eventually he was neurologically improving 10 months after the chemotherapy and adrenal enlargement, which was possibly of metastasis, was only against complete remission. This case was good outcome by biweekly CHOP using G-CSF when compared with very high mortality in reported IVL cases besides vincristine neurotoxicity under compromised blood-brain/nerve barrier due to IVL might affect the functional recovery. This case with IVL implied raised soluble IL-2 receptor and progressive cauda equina syndrome/ascending myelopathy as diagnostic clues, and efficiency of muscle biopsy to confirm IVL.

Cauda Equina↗
PubMed1997

Chlorambucil-induced structural changes in the gpt gene of AS52 cells.

The bifunctional alkylating agent chlorambucil (CBC) is a chemotherapeutic agent that induces a high yield of mouse germ-line mutations, apparently due to multi-locus deletions or other chromosomal rearrangements. We investigated the mutagenicity of CBC in cultured mammalian cells by comparing its effect in the AS52/gpt and CHO/hprt gene mutation assays, which detect large and small effects, respectively. CBC significantly increased the mutant frequency in the AS52/gpt assay, but not in the CHO/hprt assay, while the cytotoxic responses to CBC were similar in the two cell lines. This indicates that CBC induced predominantly large deletions or other gross structural changes, and not point or other small mutations. The mutational responses to CBC were similar to the responses to mitomycin C comparing them based on the cytotoxic responses. Molecular analysis of the gpt gene in AS52 mutant cells by electrophoresis following PCR amplification revealed that 81% of CBC-induced mutants lost the entire gpt gene, which is caused by large deletions or interchromosomal recombinations. The loss frequency was lower in spontaneous mutants (42%) and ethylmethanesulfonate-induced mutants (29%). This supports cytogenetic data showing that CBC is a potent clastogen in cultured mammalian cells, inducing predominantly large deletions and/or other gross structural alterations.

Animals↗