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Biomedical subjects

K Miyajima

Publications and source records attributed to K Miyajima.

At least 55 records · Page 3Linked to original sources
PubMed1997

[Surgical treatment for patients with atypical mycobacteriosis].

We have been conducting surgical therapy for patients with atypical pulmonary mycobacteriosis (AM) since 1965 and have reported on the outcome of this approach to treatment. We have found that chemotherapy is not adequately efficacious against type III Mycobacterium avium complex (MAC), which suggests that surgical intervention may be the optimum approach for MAC. Among MAC patients who were treated surgically at our hospital in the period between 1966 and 1994, 74 cases on whom postoperative follow-up observation was possible served as the subjects of the present investigation. We report here on the outcome of treatment and related problems in these patients. Thirty-nine patients gave positive results for bacterial discharge on smear tests and all were positive on culture. Operation was performed on the right lung in 46 patients and on the left lung in 16. Pneumonectomy was conducted in 10 patients and lobectomy in 20. Other operative modes used included segmental resection in 9, pyothorax in 7, and thoracoplasty in 5 patients. Postoperative bacterial excretion was observed in 15 patients and was persistent bacterial discharge were advanced cases with lesions in another lobe, cases with a past history of tuberculosis, cases of cavitation with lesions on the contralateral side or cases with massive bacterial discharge prior to surgery. Postoperative death occurred in 5 patients: the cause of death was lung cancer in 1 case, serum hepatitis in 1 case, and respiratory failure evidenced by enlarged shadows in 3 cases. These findings pointed to a marked significance of surgical therapy for MAC patients. However, recurrent bacterial discharge has been observed occasionally in some patients even 5 years after surgery. This suggests the need for careful ongoing assessment of the efficacy of surgical therapy and long-term postoperative follow-up.

Adult↗
PubMed1997

[Lung volume reduction surgery for pulmonary emphysema--report of two cases].

Lung volume reduction surgery (LVR) was practiced in 2 male patients with pulmonary emphysema to improve pulmonary function. On admission, they complained of exertional dyspnea (Grade III of the Hugh-Jones dyspnea scale). Computed tomographic scan (band display) revealed emphysematous changes throughout both lung fields, especially in bilateral upper lobes. Nuclear lung perfusion scintigraphy showed markedly diminished blood flow in both upper lobes. The bilateral upper lobes of each patient were excised through median sternotomy using the linear stapling device. The staple lines were buttressed with bioabsorbable polyglycolic acid fabric. At 1 month after LVR, the forced expiratory volume in 1 second improved, respectively, from 0.51 L to 1.27 L (Case 1) and from 0.68 L to 0.85 L (case 2). In conclusion, LVR was useful to improve pulmonary function of the patients with pulmonary emphysema.

Aged↗
PubMed1997

Effect of cholesterol on apolipoprotein A-I binding to lipid bilayers and emulsions.

The effects of cholesterol (Chol) on the interaction of apolipoprotein A-I (apoA-I) with phospholipid bilayer vesicles and lipid emulsions were investigated. ApoA-I bound to phosphatidylcholine (PC) vesicles with higher affinity and lower capacity compared to triglyceride-PC emulsions. An increase in surface Chol in triglyceride-PC emulsions decreased the binding capacity without changing the binding affinity. In contrast, addition of Chol to PC vesicles caused a marked increase in capacity and decrease in affinity for apoA-I binding. ApoA-I caused a large release of entrapped aqueous dye, calcein, from PC vesicles, whereas this apoA-I-induced leakage was relatively small in the vesicles containing Chol. The incorporation of phosphatidylethanolamine into the vesicles also exerted effects similar to those of Chol on apoA-I binding and calcein leakage. The shifts of fluorescence emission maximum of dansyl lysine, probing the surface region of membranes, indicated that Chol as well as phosphatidylethanolamine increased the headgroup space of the vesicles. The binding maximum of apoA-I was closely correlated with the emission maximum of dansyl lysine, not with the fluorescence anisotropy of I-[4-(trimethylamino)phenyl]phenylhexatriene, suggesting that the binding capacity of apoA-I to the bilayer surface was modulated by the headgroup space rather than the acyl chain fluidity. These results show that Chol affects the bilayer surface so as to allow more apoA-I to bind to bilayers and may suggest the possibility of the interaction of apoA-I with Chol-enriched membrane domains.

Animals↗
PubMed1997

A diagnostic index of vertical problems for Class III malocclusions.

A cephalometric investigation was undertaken to derive a vertical indicator--a single value derived from a series of cephalometric variables that can be used in the differential diagnosis of Class III patients. The subjects consisted of 76 Japanese female patients whose chief complaint was anterior crossbite and who presented with either open bite or anterior deep overbite. All the data were derived from the initial lateral cephalometric radiographs. The main skeletal measurements that characterize vertical problems were selected using cluster analysis, principal component analysis, and discriminant analysis. As a result, a Class III vertical indicator was derived. The vertical indicator score for deep overbite was -2.5 +/- 2.2, whereas the vertical indicator score for open bite was +2.5 +/- 2.3. This vertical indicator may be used in diagnosing the nature of vertical problems and determining the appropriate treatment and prognosis for the individual Class III female patient.

Adult↗
PubMed1996

An antimicrobial peptide, magainin 2, induced rapid flip-flop of phospholipids coupled with pore formation and peptide translocation.

The effect of an antimicrobial peptide, magainin 2, on the flip-flop rates of phospholipids was investigated by use of fluorescent lipids, i.e., anionic N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)dipalmitoyl-L-alpha- phosphatidylethanolamine (NBD-PE), 1-oleoyl-2-[12-((7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)- dodecanoyl]-L-alpha-phosphatidic acid (C12-NBD-PA), 1-oleoyl-2-[12- ((7-nitrobenz-2-oxa-1,3-diazol-4-yl)- amino)dodecanoyl]-L-alpha-phosphatidyl-L-serine (C12-NBD-PS), and zwitterionic 1-palmitoyl-2-[6-((7- nitrobenz-2-oxa-1,3-diazol-4-yl)amino)caproyl]-L-alpha-phosphatidy lcholine (C6-NBD-PC). Their intrinsic flip-flop half-lives at 30 degrees C in the absence of the peptide were 1.1 h, ca. 7 h, ca. 8 days, and > 2 days, respectively. The peptide accelerated the flip-flop half-lives of the fluorescent lipids to an order of minutes. Furthermore, the flip-flop was coupled with the membrane permeabilization and the peptide translocation [Matsuzaki, K., Murase, O., Fujii, N., & Miyajima, K. (1995) Biochemistry 34, 6521-6526], suggesting pore-mediated flip-flop. The flip-flop rate was independent of the initial labeling conditions (outer leaflet label or inner leaflet label). From these results, a model was proposed, in which the lipids translocate across the membrane by lateral diffusion along the wall of the pores composed of the peptides and the lipids. A simple theoretical calculation could explain the coupling of the flip-flop with the permeabilization.

Amino Acid Sequence↗
PubMed1996

Physical states of surface and core lipids in lipid emulsions and apolipoprotein binding to the emulsion surface.

Plasma triglyceride-rich lipoproteins vary in lipid composition during their metabolism. We investigated the effects of the lipid composition of emulsion particles, specifically those of cholesterol enrichment and core replacement (replacing core triglyceride with cholesteryl oleate), on the physical states of surface and core lipids. Steady-state and time-resolved fluorescence anisotropies were measured in lipid emulsions using 1,6-diphenylhexatriene to probe the core and 1,6-diphenylhexatriene analogues for the outer and inner hydrophobic portions of surface phospholipids. In the absence of cholesterol, core replacement had little effect on the surface rigidity, despite the large difference in core mobility. However, core replacement caused a marked increase in surface rigidity in the presence of cholesterol. Quenching experiments using the fluorescent cholesterol analogue, dehydroergosterol, indicated that core replacement allowed surface dehydroergosterol to redistribute from the inner to the outer regions in the emulsion surface. These results indicated that core replacement modulates the surface properties of the emulsion particles through the redistribution of cholesterol in the surface layers. Furthermore, core replacement significantly decreased the binding of apolipoprotein E to the emulsion surface, whereas the binding of apolipoprotein CII responded to the cholesterol enrichment. This binding behavior of exchangeable apolipoproteins may closely correlate with the location of surface cholesterol and the mobility of core lipids.

Apolipoproteins↗
PubMed1996

Transbilayer transport of ions and lipids coupled with mastoparan X translocation.

The transbilayer movement of ions and lipids induced by mastoparan X, a peptidic toxin from Vespa xanthoptera, was investigated by use of lipid vesicles as a model membrane system. Negatively charged phosphatidylglycerol remarkably enhanced the peptide-lipid interactions. Mastoparan X induced the ion flow by forming a short-lived, multimeric pore in the lipid bilayer, as determined from the leakage of an anionic dye, calcein, from the liposomes. The pore formation was coupled with the translocation of the peptide into the inner leaflet. The latter was detected by three experiments using fluorescence techniques [Matsuzaki, K., Murase, O., Fujii, N., & Miyajima, K. (1995) Biochemistry 34, 6521-6526; Matsuzaki, K., Murase, O., & Miyajima, K. (1995) Biochemistry 34, 12553-12559]. The lipid flip flop was monitored on the basis of the chemical quenching of 7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD)-labeled lipids by sodium dithionite. Mastoparan X triggered the rapid flip-flop of both negatively charged and zwitterionic lipids in coupling with the pore formation and the peptide translocation. A novel model of the mastoparan-lipid interactions was proposed to explain these observations.

4-Chloro-7-nitrobenzofurazan↗
PubMed1996

Rapid and high yield induction of endometrial adenocarcinomas in CD-1 mice by a single intrauterine administration of N-ethyl-N-nitrosourea combined with chronic 17 beta-estradiol treatment.

Induction of uterine endometrial adenocarcinomas in mice by N-ethyl-N-nitrosourea (ENU) and 17 beta-estradiol (E2) was examined. Illumination-induced persistent estrous CD-1 mice were divided into three groups at 10 weeks of age. Group 1 was given a single intra-uterine administration of polyethylene glycol (PEG) 1 week later, while Groups 2 and 3 received ENU (12.5 mg/kg), dissolved in PEG, in the same manner. Group 3 mice were also implanted with E2 pellets s.c. 1 week previously, and thereafter the pellets were renewed every 8 weeks throughout the experiment. At the termination (week 15 after the ENU treatment), all surviving mice were killed and the development of uterine proliferative lesions was assessed. All groups demonstrated endometrial hyperplasias, the severity being greatest in the ENU plus E2-treated animals (Group 3). The incidence of adenocarcinomas in Group 3 (20/29, 69%) was significantly higher than in Group 1 (0/25, 0%) or 2 (0/29, 0%). At 10 weeks after the ENU-treatment, serum E2 and progesterone concentrations in Group 3 were significantly higher and lower, respectively, than those in Groups 1 and 2. Consequently, the E2/progesterone (E2:P) ratio in Group 3 was significantly increased. These results indicate that a continuing high level of serum E2 and low level of progesterone are important for endometrial adenocarcinoma development in mice, with an increased E2:P ratio acting as a promoter for development of the endometrial lesions initiated by ENU treatment.

Adenocarcinoma↗
PubMed1996

Effects of glucose and its oligomers on the stability of freeze-dried liposomes.

The effects of glucose and its oligomers (maltodextrins) on the stability of sonicated liposomes during freeze-drying were studied by monitoring the retention of the fluorescent dye, Calcein, entrapped in the liposomal inner aqueous phase and by the use of differential scanning calorimetry (DSC). Glucose showed weak cryoprotective effects on dioleoylphosphatidylcholine (DOPC) or egg yolk phosphatidylcholine (eggPC) liposomes, while it had a relatively high cryoprotective effect on dipalmitoylphosphatidylcholine (DPPC) liposomes. Maltose and maltotriose showed high cryoprotective effects on eggPC liposomes, while other maltodextrin, longer oligomers, showed low cryoprotective effects. No saccharide was effective to protect DOPC liposomes. The fluidity and/or packing of lipid membranes had considerable influences on the stability of liposomes during the lyophilization. Maltodextrins showed relatively high cryoprotective effects on DPPC liposomes at low saccharide/lipid molar ratios, although the cryoprotective effects decreased with the increase in the molar ratios. Size measurements suggested that glucose and maltose completely prevented the aggregation and/or fusion of liposomes during lyophilization, and that other maltodextrins induced them due to their weak hydrophobic properties.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1996

Binding and uptake of liposomes containing a poly(ethylene glycol) derivative of cholesterol (stealth liposomes) by the macrophage cell line J774: influence of PEG content and its molecular weight.

The binding and intake of liposomes containing a different molar content and chain length of a PEG-Chol derivative had been studied in cultured macrophage cell line J774. The decrease in binding and endocytosis of the liposomes containing PEG-Chol is dependent on (i) the PEG chain length, (ii) the molar content of the surfactant, (iii) the liposome concentration in the external medium. The best results in reducing the uptake of liposomes were obtained by a PEG-Chol liposome suspension with a high molar content (25%) which presents a non negligible amount of free PEG-Chol. Moreover, we could show an increase by 2 for binding and by about 5 for endocytosis of filtrated-liposomes containing 25 mol% of 8800PEG-Chol, in the absence of free PEG-Chol in the suspension. Binding and intake of control liposomes was also inhibited in the presence of free PEG-Chol. Fluid phase endocytosis of SRh was inhibited up to 45% of control in the presence of liposomes containing PEG-Chol or free PEG-Chol. Based on the comparison of 4400PEG-Chol with the most commonly used PEG derivative 5000PEG-PE, PEG-Chol is more powerful in terms of reducing their binding and endocytosis by J774 cells. Inhibition of the fluid phase endocytic process is attributed to the binding of PEG-Chol to the cells' plasma membrane inducing a decrease in surface hydrophobicity of the cells, resulting in a marked decrease in the extent of phagocytic ingestion.

Animals↗
PubMed1996

Craniofacial structure of Japanese and European-American adults with normal occlusions and well-balanced faces.

The purpose of this study is to compare two groups of adults from different races who were selected on the basis of having normal ("ideal") occlusions and well-balanced faces. The lateral cephalometric radiographs of 54 Japanese adults (26 men and 28 women) were compared with a sample of 125 adults (44 men and 81 women) of European-American ancestry. The samples were chosen by orthodontists of the same racial background as the sample selected. Each lateral cephalogram was traced and digitized, and differences between cephalometric measurements between groups were analyzed with completely randomized t tests. In comparison to the European-American sample, the Japanese sample, in general, was smaller in anteroposterior facial dimensions and proportionately larger in vertical facial dimensions. The facial axis angle was more vertical in Japanese subjects, indicating a more downward direction of facial development. On average, the subjects in the Japanese sample were more protrusive dentally, with a more acute nasolabial angle and a greater tendency toward bilabial protrusion. These differences, evident even in groups with so-called "well-balanced faces", indicate that fundamental variation exists in the craniofacial structure of Japanese and European-Americans. The results of this study support the premise that a single standard of facial esthetics is not appropriate for application to diverse racial and ethnic groups.

Adult↗
PubMed1996

Treatment mechanics in Class III open bite malocclusion with Tip Edge technique.

Nonextraction treatment with nonorthognathic intervention for treatment of a skeletal Class III open bite malocclusion was performed. Light traction with effective uprighting of the lower dentition with Tip Edge brackets (TP Orthodontics, La Porte, Ind.) and anteriorly placed Class III elastics was the modus operandi. Class III elastics can prevent elongation of the upper molars and yet can cause the upper dentition to move forward. Ni-Ti wire with a reverse curve of Spee helped both the uprighting and depression of the mandibular molars. The present case was treated with the Kim philosophy but employing Tip Edge brackets. This combination was found to be very easy to manipulate and achieved good results in a very short period of time.

Adolescent↗
PubMed1996

Orthodontic treatment of an open bite patient with oral-facial-digital syndrome.

A case of oral-facial-digital syndrome was treated orthodontically. Characteristics of this case were mandibular protrusion with open bite. Occlusal stability after correction of this malocclusion was achieved with the uprighting of the posterior teeth, surgical reduction of the enlarged tonsils and highly attached tongue frenum, and oral functional training.

Adolescent↗
PubMed1995

Kinetics of pore formation by an antimicrobial peptide, magainin 2, in phospholipid bilayers.

The kinetics of the pore formation by magainin 2, an antimicrobial peptide from Xenopus laevis, in lipid vesicles was investigated. The pore formation was estimated by the efflux of a fluorescent dye, calcein, from large unilamellar vesicles composed of egg yolk phosphatidylglycerol. The time courses of the dye release were well-described by a novel model in which the peptide molecules translocate from the outer to the inner monolayer by forming a pore. The concentration dependence of the leakage rate suggested that the pore consists of pentameric magainin. The obtained kinetic parameters estimate that, at a lipid-to-peptide molar ratio of 117, 9 pores with a lifetime of 40 microseconds open per second per vesicle in the initial phase. The apparent deactivation of the pore with increasing time can be ascribed to the reduced peptide density in the outer leaflet due to the translocation. Incorporation of phosphatidylcholine destabilized the pore, indicating the importance of anionic lipids in the stable pore formation.

Amino Acid Sequence↗