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Biomedical subjects

M Kitano

Publications and source records attributed to M Kitano.

At least 19 recordsLinked to original sources

Biodegradation ranks of priority organic compounds under anaerobic conditions.

The biodegradations of 52 priority organic compounds were evaluated under anaerobic conditions by two tests developed in a preceding paper (Urano et al., 1995). Namely, the biodegradabilities of the compounds were classified into 13 ranks by the method proposed by Urano et al. (1995). Most of the aliphatic alcohols and carboxylic acids were not inhibitory and were biodegraded, but the compounds having ether bonds or branched hydrocarbon groups were biodegraded slowly. Aliphatic aldehyde and amines were not so much inhibitory but were hardly biodegraded. The benzene substitutes having groups of -CH2OH, -CHO, -CH2CH(NH2)COOH, -COOH and -OH were easily biodegraded, but the compounds having groups of -NO2, -NH2 and -SO3H were hardly biodegraded. Most of the nitro compounds were inhibitory in the higher concentration test though they were reduced into amino compounds. Since the biodegradation characteristics of many organic compounds could be classified and discussed appropriately, the suitability of the proposed method is substantiated.

Anaerobiosis

Testing and classification methods for the biodegradabilities of organic compounds under anaerobic conditions.

Biodegradability is one of the most important characteristics of an organic compound for predicting its fate and life in the environment and its application in biological wastewater treatment. But there is no general testing method for biodegradability under anaerobic conditions. The biodegradabilities of thirteen principal organic compounds was investigated in a batch test using vials under various conditions, such as the concentration of an organic compound, the cultivation method and the concentration of anaerobic bacteria for seeding. Two test methods in the standard concentration and the low concentration were developed. A new method to classify the biodegradabilities of organic compounds into thirteen ranks was proposed by considering inhibition, complete biodegradation and first step biodegradation.

Bacteria, Anaerobic

Characterization of nodules induced by bioactive glass on cultured periodontal-ligament fibroblasts.

We previously reported that materials leached from bioactive glass (BG) and vitamin D3 induced the formation of nodules on cultured periodontal-ligament fibroblasts (PLF). In this study, we have investigated the relationship between the conditions of the materials and nodule formation, analyzed morphologically, and also studied whether the production of nodules was specific to cultured PLF. PLF and skin fibroblasts were cultured in the presence or absence of BG. The amounts of calcium, phosphate, sodium and silicon in the culture medium and the number of nodules were measured at the 55th day. The nodules were observed microscopically and analyzed using an X-ray microanalyzer. In PLF, nodules were formed regardless of the presence or absence of BG; however, they were more numerous in the presence of BG. In skin fibroblasts, nodules were not observed. The amounts of calcium and silicon were higher in the presence of BG, while the amount of phosphate was lower. The nodules appeared crystalline with a spongy structure and contained calcium and phosphorus. Our results show that the nodules were associated with PLF and precipitated by the materials (higher concentrations of calcium and silicon), and they were spongy crystal composed of calcium and phosphorus.

Biocompatible Materials

Spatially distributed responses induced by contrast reversal in cat visual cortex.

Field potentials were recorded from cat striate cortex, either between an epidural screw electrode and a cannula-electrode inserted deep in the gray matter (transcortical recording) or with a pair of metal microelectrodes. Electrodes were placed bilaterally near the cortical projection of the area centralis. The horizontal separation of the recording tips was approximately 2 mm and approximately 300 microns, respectively. The area of the visual field providing input to the recording site (receptive field) was determined by measuring the field potentials generated by contrast reversal of high-contrast, achromatic bar gratings. Five-degree-diameter grating patches were presented individually over a large area of the visual field. The gratings were contrast-reversed at 4, 6 or 10 Hz, while also being swept in spatial frequency between 0.56 and 5.24 c/deg. The receptive fields were approximately 20 deg across or more, substantially larger than expected on the basis of cortical retinotopy. Responses were also elicited by stimulation of the hemi-field contralateral to that contributing to the classical receptive field, implicating the presence of a callosal projection. The large, spatially distributed receptive fields consisted of patches of high and low sensitivity. Continuous cortical infusion of either 100 microM tetrodotoxin or 10 mM muscimol at the recording site totally suppressed the transcortically recorded field potentials, proving that the local field potentials were generated postsynaptically. The present findings suggest that a cluster of cortical cells near the projection site of the area centralis receives input from remote cortical regions to an extent that is comparable with that of anatomically demonstrated long-range lateral connections.

Animals

Molecular analysis of extracellular-superoxide dismutase gene associated with high level in serum.

Extracellular-superoxide dismutase (EC-SOD) is one of the SOD isozymes mainly distributed in the extracellular fluid. In the vascular system, it is located on the endothelial cell surface according to studies on the heparin binding capacity. By measurement of serum EC-SOD levels of Japanese in healthy persons (n = 103) and hemodialysis patients (n = 150), 7 healthy subjects and 24 hemodialysis patients were classified into group II associated with high EC-SOD levels. By molecular analysis of the EC-SOD coding region from the group II individuals in Sweden, a single nucleotide substitution of G to C generating an amino acid change of arginine to glycine has been identified in the region associated with the heparin affinity of the enzyme. The same mutation was detected in the Japanese as a homozygote in both alleles of 2 hemodialysis patients and as a heterozygote in one allele of all the healthy group II individuals and 17 hemodialysis patients. The amino acid substitution may result in the decrease of the heparin affinity which is favorable for the existence of EC-SOD in the serum.

Amino Acid Sequence

Systemic artery-to-pulmonary artery shunt after using an omental pedicle flap.

A 66-year-old man was hospitalized because of hemoptysis. Four years earlier, he had undergone an operation involving the use of an omental pedicle flap that was supplied by the right gastroepiploic artery for the treatment of empyema. Arteriography revealed that the right gastroepiploic artery communicated with the periphery of the right pulmonary artery. The right gastroepiploic artery was divided surgically.

Abdominal Muscles

Right ventricular function evaluated by volumetric analysis during left heart bypass in a canine model of postischemic cardiac dysfunction.

Right ventricular function during left heart bypass was evaluated by volumetric analysis with a conductance catheter in 12 dogs with postischemic cardiac dysfunction. The conductance catheter was used to assess the volumetric status of the right ventricle and thereby allowed a right ventricular pressure-volume curve to be obtained, in which transient volume loading on the right ventricle was applied. The following right ventricular properties during left heart bypass were assessed and compared with properties measured without left heart bypass, by means of load-independent parameters: maximum elastance, stroke work/end-diastolic volume relation, end-diastolic pressure/volume relation, and stroke work/end-diastolic pressure relation. The stroke volume derived from the conductance catheter and the electromagnetic flow probe showed good linear correlation (r2 = 0.733 to 0.975). After initiation of left heart bypass, maximum elastance did not change significantly, although volume intercept significantly increased, from 1.2 +/- 7.3 to 3.6 +/- 7.9 ml (p < 0.05). End-diastolic pressure/volume relation was well fitted to the exponential curve (EDP = e(k1.EDV+k2)) and was shifted to the right and downward during left heart bypass; the slope k1 significantly decreased, from 0.12 +/- 0.06 to 0.10 +/- 0.07 (p < 0.01). Stroke work/end-diastolic volume relation and stroke work/end-diastolic pressure relation were closely fitted to the linear regression, and their slopes were significantly increased during left heart bypass, from 0.14 +/- 0.08 to 0.18 +/- 0.08 (p < 0.05) and from 0.22 +/- 0.15 to 0.34 +/- 0.19 (p < 0.01), respectively. These results suggest that the decompression of the left ventricle and septal shifting by left heart bypass provide good diastolic compliance and good systolic performance because of afterload unloading of the right ventricle. Thus the left heart bypass improved the overall right ventricular performance, particularly at higher end-diastolic pressures, in dogs with postischemic cardiac dysfunction.

Animals

Bacterial invasion into dentinal tubules of human vital and nonvital teeth.

The difference in resistance to bacterial invasion into the dentinal tubules between vital and nonvital teeth has not been determined. This study was conducted to clarify the effect of vital pulp on bacterial invasion into the dentinal tubules. The specimens were 19 intact pairs of bilateral upper third molars of 19 healthy, young adult male volunteers. In each case, 30 or 150 days before extraction, pulpectomies and root canal fillings were carried out unilaterally and a class V cavity involving the dentin was made on the palatal surface of both the pulpectomized tooth and the nonpulpectomized opposite tooth. The cavities were left unprotected to expose them to oral flora until the extractions were done, and the extracted teeth were examined histologically. When extraction followed 150-day exposure to the oral flora, there was a statistically significant difference in the bacterial invasion rate between the vital and nonvital teeth. It was postulated that vital teeth were much more resistant to bacterial invasion into the dentinal tubules than were nonvital teeth, thereby suggesting that the vital pulp plays some important role in this process.

Adult

Inhibition of intestinal tumor development in rat multi-organ carcinogenesis and aberrant crypt foci in rat colon carcinogenesis by 22-oxa-calcitriol, a synthetic analogue of 1 alpha, 25-dihydroxyvitamin D3.

The modifying effects of 22-oxa-calcitriol (OCT), a synthetic analog of 1 alpha,25-dihydroxyvitamin D3, were assessed in a multi-organ carcinogenesis model using male F344 rats initially treated with five kinds of carcinogens. In experiment 1 the rats were given OCT intraperitoneally at doses of 30 micrograms/kg (25 rats) or 3 micrograms/kg (25 rats), three times a week for 24 weeks after initial carcinogen exposure over 4 weeks and a 2 week non-treatment period. Twenty-two rats received the five carcinogens and were given the vehicle intraperitoneally as a control. A further group of 10 rats was given the 30 micrograms/kg dose of OCT without prior carcinogen application. At the end of the total observation period of 30 weeks the carcinoma incidence in the small intestine of rats given 30 micrograms/kg OCT after carcinogen treatment was 0%. This incidence was significantly smaller when compared with the control group. The incidence of large intestine carcinomas in the 30 micrograms/kg OCT group showed a tendency to decrease. The numbers of small and large intestinal carcinomas per rat were also significantly lower in the group given 30 micrograms/kg OCT than after 3 micrograms/kg OCT or carcinogens alone. Attention was, therefore, focused on colon carcinogenesis and in experiment 2 30 micrograms/kg OCT administered six times a week to rats for 8 weeks after the last injection of N,N'-dimethylhydrazine (DMH) exposure. OCT significantly reduced the formation of DMH-induced aberrant crypt foci, considered to be putative preneoplastic lesions. In experiment 3 30 micrograms/kg OCT was administered six times a week to rats for 4 weeks without prior carcinogen treatment. The proliferating cell nuclear antigen labeling index for the colonic epithelium of rats given 30 micrograms/kg OCT was decreased. Ornithine decarboxylase and spermidine/spermine N1-acetyltransferase activities in colonic epithelium, assayed as indicators of cell proliferation, were not significantly decreased as compared with control group values. Furthermore, vitamin D receptors in colonic epithelium were not significantly increased. Thus the present study indicates that OCT can exert inhibitory effects on tumor development in the small and large intestines, although the mechanism is unclear.

Acetyltransferases

Lack of promoting effects of alpha-linolenic, linoleic or palmitic acid on urinary bladder carcinogenesis in rats.

Potential promoting effects of alpha-linolenic, linoleic and palmitic acids were investigated in a two-stage urinary bladder carcinogenesis model. In experiment 1, male F344 rats were given 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in their drinking water for 4 weeks and then basal diet containing 10% alpha-linolenic, 10% linoleic or 10% palmitic acid along with 0.2% butylated hydroxyanisole (BHA) as an antioxidant for 24 weeks. The development of tumors in the urinary bladder was not increased by treatment with any of the fatty acids. In experiment 2, male F344 rats were given 10% alpha-linolenic, 10% linoleic or 10% palmitic acid along with 0.2% BHA in their diet for 8 weeks without prior BBN treatment. The administration of fatty acids was not associated with any increase in the 5-bromo-2'-deoxyuridine labeling index of the urinary bladder epithelium. Serum and/or urine fatty acid levels increased in the cases of alpha-linolenic and linoleic acid treatments, but not with palmitic acid. Under the present experimental conditions neither the two polyunsaturated nor the one saturated fatty acid exerted any promoting effect on urinary bladder carcinogenesis.

Animals

Modification of delayed-type hypersensitivity reactions by muramyldipeptide in guinea pigs.

N-Acetylmuramyl-L-alanyl-D-isoglutamine (muramyldipeptide, MDP) modulated delayed-type hypersensitivity (DTH) reactions and induced severe inflammatory lesions in guinea pigs. The animals immunized with heat-killed Mycobacterium tuberculosis were challenged with the purified protein derivative (PPD) at the flanks and the corneas to prepare DTH reactions at 2 weeks after the immunization, thereafter 24 h the animals received subcutaneous injections of MDP at the flanks of the opposite side. At the skin with the DTH reaction, increase of swelling and redness accompanied with hemorrhage and necrosis were observed. As corneal reactions in the animals that had received MDP, increase of cornea thickness, opaque and grayish-white and the projection of eyes accompanied with severe iritis were observed. Modification of the skin reaction occurred from 2 h after the MDP injection, rapidly increased to the maximum level around 10 h, maintained the level until 24 h, then slowly decreased. The polymorphonuclear leukocyte infiltration was observed from 15 min after the MDP injection, and tumour necrosis factor alpha, interleukin (IL)-1, and IL-6 levels in the serum and skin lesions increased after the MDP injection. Synthetic muramyltripeptide (N-acetylmuramyl-L-alanyl-D-isoglutaminyl-L-lysine) also provoked definite skin reactions, while the larger peptidoglycan fragments and various inflammatory agents including cytokines so far examined were inactive in this respect. Cortisone and heparin inhibited definitely and slightly the reaction, respectively. A comparison was made with the modified DTH reaction and the necrotic reactions which we reported previously.

Acetylmuramyl-Alanyl-Isoglutamine

Studies on pyridonecarboxylic acids. IV. Synthesis and antibacterial activity evaluation of S-(-)- and R-(+)-6-fluoro-1-methyl-4-oxo-7- (1-piperazinyl)-4H-[1,3] thiazeto[3,2-a]quinoline-3-carboxylic acids.

Optically active isomers of 6-fluoro-1-methyl-4-oxo-7-(1-piperazinyl)-4H- [1,3] thiazeto [3,2-alpha] quinoline-3- carboxylic acid (NM394, 3) were prepared through optical resolution of their racemic intermediate ( +/- )-1 by high-performance liquid chromatography (HPLC). The absolute configuration at the C-1 position in the thiazeto-quinolone ring of ( - )-3 was confirmed by X-ray analysis ( - )-4 to be S. The in vitro antibacterial activity of ( - )-3 was 2--8 times that of (+)-3.

Anti-Infective Agents

Plasma exchange in chronic inflammatory demyelinating polyradiculoneuropathy; different beneficial effects and their correlation to the clinical features.

We report 7 patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) who showed significant clinical improvement by plasma exchange (PE). Their clinical features were extensively varied but fulfilled the diagnostic criteria for CIDP. The patients could be divided into 2 subgroups based on the mode of effectiveness of PE; one group consisted of those who once achieved complete remission, but required highly frequent PEs for long-term maintenance of remission and the others were those who showed persistent and complete remission with several sessions of PE alone. These findings raise issues about the long-term therapeutic goals to be achieved by PE for CIDP patients, particularly on supportive therapy other than PE, as well as the optimization of frequency and duration of PE.

Adult

Glandular odontogenic cyst: analysis of cytokeratin expression and clinicopathological features.

The glandular odontogenic cyst (GOC) is a rare odontogenic cyst which is still controversial in regard to classification, terminology, and origin. The first Japanese case of GOC is reported. Immunohistochemical examination for expression of cytokeratins and epithelial membrane antigen by monoclonal antibodies suggested that the lining epithelium was of odontogenic origin with metaplastic mucus-laden cells. We have reviewed the literature and compared the clinicopathological findings of the reported case of GOC with those of botryoid odontogenic cysts (BOC). The anatomical location, age range, and sex of GOC cases were very similar to those of BOC. GOC appears to be a multiocular and mucoepidermoid variant of non-keratinizing odontogenic cysts, which also includes BOC. GOC should be separated from the other types of odontogenic cyst and central mucoepidermoid tumours of salivary gland origin.

Aged

Studies on pyridonecarboxylic acids. 1. Synthesis and antibacterial evaluation of 7-substituted-6-halo-4-oxo-4H-[1,3]thiazeto[3,2-a]quinoline-3- carboxylic acids.

A series of [1,3]thiazeto[3,2-a]quinoline-3-carboxylic acids and their esters were prepared and evaluated for antibacterial activity. The derivatives with a hydrogen or methyl group at C-1, fluorine at C-6, and piperazinyl or 4-methyl-1-piperazinyl group at C-7 showed superior in vitro antibacterial activity, and the derivatives with 4-methyl-1-piperazinyl group at C-7 had potent in vivo activity. Compound 29a (NM394) showed excellent in vitro antibacterial activity and low toxicity but poor absorption from the gastrointestinal tract. Compound 29ee (NM441), an N-[(5-methyl-2-oxo-1,3-dioxol-4-yl)methyl] derivative of 29a, was found to possess a favorable pharmacokinetic profile and oral activity superior to that of ciprofloxacin in experimental animals.

Administration, Oral

Meningioma of the mandible.

This is the first case report to the authors' knowledge of a primary extracranial meningioma located in the mandible. Ultrastructurally, the tumor cells had intricate cellular membranes and desmosome-like attachment structures. Using immunohistochemical analysis, the tumor expressed both epithelial membrane antigen and vimentin. Although the origin of extracranial meningiomas has been attributed to proliferation of ectopic embryonal nests of arachnoidal cells, the proliferation of perineural cells of peripheral nerves also is possible as a result of the structural and functional similarities of perineural cell and arachnoid cells. The authors suggest that extracranial meningiomas may be more common than published reports indicate because of certain histologic similarities between these tumors, neurilemomas, and solitary neurofibromas.

Biomarkers

Paraganglioma of the posterior mediastinum: value of magnetic resonance imaging.

A case of paraganglioma arising in the posterior mediastinum in a 29-year-old man diagnosed by magnetic resonance imaging is reported. Excision of mediastinal paraganglioma is often hazardous because of its rich vascular supply and tendency to involve surrounding structures. Magnetic resonance imaging is valuable for the preoperative diagnosis of this vascular tumor as well as for determination of its resectability and appropriate surgical procedure.

Adult