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Biomedical subjects

Y Kobayashi

Publications and source records attributed to Y Kobayashi.

At least 217 records · Page 12Linked to original sources
PubMed2001

Issues of intervention aimed at preventing prospective surplus of physicians in Japan.

OBJECTIVES: In Japan, regulatory intervention aimed at preventing a prospective surplus of physicians is an important medical issue. The study committees organized by the Ministry of Health and Welfare (MHW) in 1986, 1993 and 1998, concluded that the number of physicians would exceed demand for their services in the future. As a result, the government planned to reduce the number of medical students. However, MHW has not been successful in the intervention so far, as shown by the fact that their initial plan for a 10% reduction in the number of students enrolled in medical school has not been attained. In this paper, we examine why the MHW policy failed. METHODS: We reviewed those forecasts performed by past MHW study committees and examined whether the government policy of controlling physician training was appropriate. Additionally, we did a preliminary projection of specialty-specific demand for physician services as a reference for future physician manpower policies in Japan. RESULTS: We found that both conflicts among various interest groups and a lack of precise projections of physician services hampered the proper formation and implementation of a physician manpower policy in Japan. CONCLUSIONS: It might be necessary to examine the appropriateness of the MHW policy in reducing the overall number of students enrolled in medical schools. As a first step in formulating and implementing a physician manpower policy, we should begin to consolidate the necessary data to conduct precise and proper projections of future physician demand.

Adolescent↗
PubMed2001

A randomized comparison of the straight linear approach with electrogram mapping focal approach in selective slow pathway ablation.

The aim of this study was to evaluate the efficacy and safety of the anatomic linear approach in selective AVN slow pathway ablation, in comparison to the widely used electrogram mapping focal approach. It remains undetermined whether or not anatomic linear ablation has a greater potential for eliminating slow pathway conduction than does focal ablation. Fifty consecutive patients (21 men, 29 women, age 56 +/- 14 years) with common type AVNRT were randomly assigned to the linear approach (25 patients) or local electrogram mapping approach (25 patients). A linear lesion was created between the tricuspid annulus, at the midlevel of the coronary sinus (CS) ostium, and the anterior aspect of the CS infundibulum. In 22 (88%) patients in the linear group, the AVNRT was successfully eliminated by 1.5 +/- 0.8 linear RF applications without any complications. All 25 patients in the focal group satisfied the endpoint criteria after 3.8 +/- 2.4 focal RF deliveries. The success rate did not significantly differ between the two groups. Out of the 22 patients with a successful outcome in the linear group, 17 (77%) attained complete abolition of the slow pathway conduction, whereas this was observed in only eight (32%) patients in the focal group (P < 0.005). The session time was significantly shorter in the linear group. Recurrence of the tachycardia was not documented in any patient during a mean follow-up of 18 +/- 8 months except one with residual slow pathway conduction in the focal ablation group. In conclusion, the anatomic linear approach can be performed safely and possesses a greater potential for slow pathway interruption compared to the electrogram mapping focal approach.

Adult↗
PubMed2001

Isoform-selective upregulation of mast cell chymase in the development of skin fibrosis in scleroderma model mice.

The involvement of connective-tissue-type mast cells and chymase, a protease unique to their secretory granules, has been implicated in fibrotic diseases. To elucidate the role of chymase in fibroproliferative inflammation, in this study we examined the enzymatic activity and mRNA expression of chymase in the sclerotic skin of tight-skin mice; syngeneic Pallid mice served as the control. Dorsal skin specimens from mice aged 5, 10, and 20 wk were evaluated by morphometric and biochemical analyses. At ages 10 and 20 wk, the hydroxyproline concentration in tight-skin dermis was higher than that in Pallid. At any age, the subcutaneous fibrous layer was thicker in tight-skin than in Pallid. In accordance with these fibrous changes, both connective-tissue-type mast cell counts and chymase activity were higher in tight-skin skin than in Pallid skin up to 20 wk of age. Age-matched (10-wk-old) tight-skin and Pallid were quantified for their mRNA of connective-tissue-type mast-cell-specific chymase, mouse mast cell protease-4, by the competitive reverse transcriptase polymerase chain reaction technique, which revealed its higher level in tight-skin than Pallid. In contrast, the mRNA level of mouse mast cell protease-5, the chymase isoform of undifferentiated mast cells, in tight-skin skin was only a tenth that of mouse mast cell protease-4 and no different from the mouse mast cell protease-5 mRNA level of Pallid mice. An in situ hybridization study confirmed the higher expression of mouse mast cell protease-4 by connective-tissue-type mast cells in tight-skin skin than Pallid skin. These results strongly support the contention that the connective-tissue-type mast cell chymase plays a crucial role in fibroproliferative remodeling of the skin.

Animals↗
PubMed2001

Mass spectrometry proves under-O-glycosylation of glomerular IgA1 in IgA nephropathy.

BACKGROUND: The IgA1 molecule, which is predominantly deposited in glomeruli in IgA nephropathy (IgAN), is a unique serum glycoprotein because it has O-glycan side chains in its hinge region. Our study was conducted to investigate the O-glycan structure in the glomerular IgA1 in IgAN. METHODS: The IgA1 was separated from 290 renal biopsy specimens of 278 IgAN patients and from four serum IgA1 samples (IgAN, 2; control, 2). The variety of O-glycan glycoform was determined by estimating the precise molecular weights of the IgA1 hinge glycopeptides using matrix-assisted laser desorption ionization time of flight mass spectrometry. RESULTS: The peak distribution of IgA1 hinge glycopeptides clearly shifted to lesser molecular weights in both glomerular and serum IgA1 in IgAN compared with the serum IgA1 of controls. In the five major peaks of IgA1 hinge glycopeptides in each sample, the numbers of carbohydrates composing O-glycans (GalNAc, Gal, and NANA) in the deposited and serum IgA1 in IgAN patients were significantly fewer than those in the serum IgA1 in the control groups. CONCLUSION: The O-glycan side chains in the hinge of the glomerular IgA1 were highly underglycosylated in IgAN. These results indicate that the decreased sialylation and galactosylation of the IgA1 hinge glycopeptides play a crucial role in its glomerular deposition in IgAN.

Adult↗
PubMed2001

Echocardiographic features in a patient with primary oxalosis.

Primary oxalosis is a rare congenital disorder of oxalate metabolism characterized by deposits of calcium oxalate in several organs, including the heart. We present the case of a 38-year-old man with primary oxalosis who had unique echocardiographic findings. Two-dimensional echocardiography revealed the sparkling high intensity echocardiographic pattern and concentric thickening of myocardial walls. Microscopic examinations showed the extensive deposits of calcium oxalate crystals in the myocardium. Therefore, we suggest that primary oxalosis should be given important consideration in the differential diagnosis of a hypertrophied myocardium with high intensity echocardiograms.

Adult↗
PubMed2001

Living donor liver transplantation for Budd-Chiari syndrome with inferior vena cava obstruction and associated antiphospholipid antibody syndrome.

BACKGROUND: Recently, the antiphospholipid antibody syndrome (APLS) has been recognized as the cause of the Budd-Chiari syndrome (BCS) in adults. However, APLS-induced BCS has been seen rarely in children. The surgical strategy for BCS depends on the patency of the inferior vena cava (IVC) and on the primary disease. METHODS: A 10-year-old boy with a diagnosis of BCS complicated with IVC obstruction caused by APLS received medical treatment and radiologic intervention for 2 years. In spite of these treatments, no relief of the symptoms could be achieved. Finally, the patient underwent living donor liver transplantation (LDLT), which required cavoplasty. He has had an uneventful course since the LDLT. CONCLUSIONS: IVC-obstructed BCS associated with APLS seems to be a good indication for LDLT with cavoplasty. Because liver transplantation (LT) itself is not a cure for APLS, the risk of thrombosis cannot be eliminated entirely by LT. Although immunosuppression may influence antiphospholipid antibody production, long-term observation and life-long anticoagulant treatment is needed even after LT. J Pediatr Surg 36:659-662.

Antiphospholipid Syndrome↗
PubMed2001

The positive inotropic and chronotropic effects of evodiamine and rutaecarpine, indoloquinazoline alkaloids isolated from the fruits of Evodia rutaecarpa, on the guinea-pig isolated right atria: possible involvement of vanilloid receptors.

Cardiotonic effects of evodiamine and rutaecarpine, constituents of the fruits of Evodia rutaecarpa Bentham Rutaceae, were evaluated on guinea pig isolated atria. Comparison with capsaicin, a vanilloid receptor agonist, revealed similar positive inotropic and chronotropic activity, as judged from antagonistic effects of the competitive vanilloid receptor (capsaicin receptor) antagonist capsazepine, the non-competitive vanilloid receptor antagonist ruthenium red, the calcitonin gene related peptide antagonist CGRP(8-37), the P2X purinoceptor antagonist PPADS, and various desensitization studies. Evodiamine and rutaecarpine produced transient positive inotropic and chronotropic effects on the guinea-pig isolated atria, followed by a desensitizing effect to additional administration. Dose-response relationships for evodiamine, rutaecarpine and capsaicin were obtained. All the compounds evoked positive inotropic and chronotropic effects in a concentration-dependent manner. Maximal contractions for evodiamine, rutaecarpine and capsaicin were observed at concentrations of 1 microM, 3 microM and 0.3 microM, respectively. The cardiotonic responses evoked by both evodiamine and rutaecarpine were shifted to the right by capsazepine, an established antagonist of vanilloid receptor (capsaicin-receptor). The effects of both evodiamine (1 microM) and rutaecarpine (3 microM) were abolished by pretreatment with a desensitizing dosage of capsaicin (1 microM), developing cross-tachyphylaxis between these compounds. The effects of evodiamine (1 microM), rutaecarpine (3 microM) and capsaicin (0.3 microM) were also significantly reduced by pretreatment with ruthenium red (10 microM) and CGRP (8-37) (10 microM). The effects of evodiamine, rutaecarpine and capsaicin were not affected by pretreatment with PPADS (100 microM), a highly selective P2X purinoceptor antagonist, and the possibility of the involvement of the P2X purinoceptor was excluded. These results suggest that the positive inotropic and chronotropic effects on the guinea-pig isolated right atria induced by both evodiamine and rutaecarpine could be attributed to their interaction with vanilloid receptors and the resultant release of CGRP, a cardiotonic neurotransmitter, from capsaicin-sensitive nerves as with capsaicin.

Alkaloids↗
PubMed2001

Rapid progress of acute suppurative cholangitis to secondary sclerosing cholangitis sequentially followed-up by endoscopic retrograde cholangiography.

A 66-year-old man was admitted to our hospital because of right hypochondralgia and fever after colonic polypectomy. Endoscopic examination revealed purulent bile excretion from the duodenal papilla orifice; based on this finding, acute suppurative cholangitis was diagnosed. An endoscopic retrograde cholangiography revealed no abnormality in the biliary tree. However, chronic cholestasis persisted, and endoscopic cholangiography performed 4 months later disclosed a beaded appearance of the intrahepatic bile ducts; this sign is a characteristic finding of sclerosing cholangitis. This is the first report of rapid progression of acute suppurative cholangitis to secondary sclerosing cholangitis sequentially followed-up by endoscopic retrograde cholangiography.

Acute Disease↗
PubMed2001

Capsaicin-like anti-obese activities of evodiamine from fruits of Evodia rutaecarpa, a vanilloid receptor agonist.

Evodiamine, a major alkaloidal principle of Evodia fruits (Evodia rutaecarpa, Rutaceae), showed vanilloid receptor agonistic activities comparable to capsaicin. The Chinese literature refers to Evodia fruits as a "hot nature" herb. In spite of the similarities in the actions of evodiamine and capsaicin in vitro, evodiamine has no perceptible taste, including a peppery hot taste. Therefore, the effectiveness of evodiamine and the extract of Evodia fruits in preventing obesity on male C3H mice, or male SD rats were examined. When evodiamine was supplemented at 0.03% of the diet and fed to mice for 12 days, the perirenal fat weight became significantly lower than in the control group. The epididymal fat mass was also decreased in the evodiamine diet group. When evodiamine was supplemented at 0.02% in the form of ethanol extract of Evodia fruits to the high-fat diet and fed to rats for 21 days, the body weight, the perirenal fat weight, epididymal fat weight, the levels of serum free fatty acid, total lipids in the liver, triglyceride in the liver, and cholesterol level in the liver were significantly reduced as compared with the control diet group. Furthermore, both lipolytic activity in the perirenal fat tissue and specific GDP binding in brown adipose tissue mitochondria, as the biological index of enhanced heat production, were significantly increased in the evodiamine fed rats. Fasting mice subcutaneously administered 1-3 mg/kg evodiamine showed decreased core body temperature by 1-2 degrees C. This hypothermic effect was prevented by the pretreatment of intraperitoneally administered 10 mg/kg capsazepine, a vanilloid receptor antagonist. On the other hand, food-sated mice subcutaneously administered 1-3 mg/kg evodiamine showed unchanged core body temperature and increased tail skin temperature by more than 5 degrees C, suggesting the increased energy expenditure by enhanced heat dissipation. In conclusion, we have demonstrated that a novel non-pungent vanilloid receptor agonist, evodiamine, mimics the characteristic anti-obese effects induced by capsaicin. Evodiamine would induce heat loss and heat production at the same time and dissipate food energy, preventing the accumulation of perivisceral fat and the body weight increase.

Adipose Tissue↗
PubMed2001

Expression of sex steroid hormone receptors in human cornea.

PURPOSE: Previously we reported the occurrence of estrogen receptor alpha (ER beta), estrogen receptor beta (ER beta) and androgen receptor (AR) in mouse corneas. The present study was designed to investigate the occurrence of various sex steroid hormone receptors, including ER alpha, progesterone receptor (PR) and AR, in human corneas. METHODS: We used reverse transcription-polymerase chain reaction (RT-PCR) to look for sex hormone receptor mRNAs (ER alpha, PR and AR) in human corneal epithelial cells obtained at autopsy. Next, using an immunocytochemical technique, we localized these receptors in donor human corneas. RESULTS: mRNAs encoding all receptors tested for were found in corneal epithelial cells obtained from male and female donor eyes. Immunocytochemical examination revealed that the receptors were located in the nuclei of corneal epithelial, stromal, and endothelial cells. CONCLUSIONS: Since receptors for both male and female sex hormones are present in human corneas of both genders, we postulate that the receptors may influence the biological functions of corneal cells through direct interaction with specific hormones.

Aged↗
PubMed2001

Eleven phthalate esters and di(2-ethylhexyl) adipate in one-week duplicate diet samples obtained from hospitals and their estimated daily intake.

Plasticizers in duplicate diet samples obtained over 1 week were analysed in order to estimate daily intake. The phthalate esters were as follows: diethyl, dipropyl, dibutyl, dipentyl, dihexyl, butylbenzyl, dicyclohexyl, di(2-ethylhexyl), dioctyl, diisooctyl (mixture of isomers) and diisononyl (mixture). Di(2-ethylhexyl) adipate was also determined. Homogenized samples of composite meals were extracted with acetonitrile, lipids were removed by extraction into n-hexane and the acetonitrile layer was cleaned using Florisil and Bondesil PSA dual layer column. Phthalates were determined by GC/MS (SIM). Phthalate recovery from the fortified food mixture by this method was 62.5-140.8%. Quality assurance as assessed by three laboratories indicated coefficient of variance in the levels of detected phthalates in same lot samples as below 10%. Detection limits were 0.1-23 ng/g for each phthalate. One-week duplicate diet samples provided by three hospitals in three remote prefectures of Japan were analysed as individual meals. In all 63 samples, DEHP was present at the highest level among all phthalates in the range 10-4400 ng/g. The intake of plasticizers estimated from all samples was 519 microg DEHP/day, 86 microg DEHA/day, 65 microg DINP/day, and 4.7 microg BBP/day. Calculated DEHP in 2-day samples out of 21 days exceeded EU TDI for a person of 50 kg body weight (1850 microg per day). Disposable PVC gloves used during the preparation of meals were suspected as the source of the high DEHP content. One-day intake of the other phthalates and DEHA was below 7% of TDI in all cases. High concentrations of DEHP (5990 ng/g) was found in baby food used in quality assurance work. The source of contamination was the PVC-tube used during production and was effectively reduced by replacing the tube by one made of stainless steel.

Adipates↗
PubMed2001

Direct MR arthrography of plica synovialis mediopatellaris.

OBJECTIVE: To evaluate the efficacy of direct MR arthrography for diagnosing plica synovialis mediopatellaris (PSM). MATERIAL AND METHODS: Twenty-two knees of 19 patients were examined by direct MR arthrography. In 19 of those knees, field-echo T2*-weighted transaxial images were obtained with intra-articular administration of 40 ml of saline ("direct MR arthrography"). In the other 3 knees, T1-weighted transaxial images were obtained with intra-articular administration of 40 ml of gadopentetate dimeglumine. Conventional MR images were evaluated prior to direct MR arthrography in 12 of the 22 knees. The results of direct MR arthrography and conventional MR imaging were compared with the arthroscopic findings. RESULTS: Direct MR arthrography demonstrated 17 of 19 PSMs proved on arthroscopy. The features of 16 PSMs on direct MR arthrography corresponded accurately with the arthroscopic classification. Conventional MR demonstrated only 3 plicae. CONCLUSION: Direct MR arthrography enabled accurate diagnosis of PSMs and could replace diagnostic arthroscopy.

Adolescent↗
PubMed2001

Plasma thrombomodulin levels in children with atopic dermatitis.

UNLABELLED: Plasma thrombomodulin (TM) levels were measured in 68 patients with atopic dermatitis (AD) and 35 controls. Plasma TM levels in patients with AD were significantly higher than those of controls (p < 0.01). A significant correlation was observed between plasma TM levels and skin scores of AD or peripheral eosinophil counts (p < 0.01). There was also a positive correlation between plasma TM and vascular cell adhesion molecule-1 levels (p < 0.05). CONCLUSION: These results suggest that plasma TM levels may reflect a severity of AD and/or endothelial cell activation induced by an allergic inflammation.

Child, Preschool↗
PubMed2001

Administration of osteocalcin accelerates orthodontic tooth movement induced by a closed coil spring in rats.

The effect of local administration of osteocalcin (OC) on experimental tooth movement was examined in the rat. The maxillary first molar was first moved mesially with an initial tipping force of 30 g with a closed-coil spring anchored to the incisor for 10 days (n = 48). Three experimental groups (n = 8) were injected with purified rat OC at doses of 0.1, 1, and 10 micrograms, respectively. The injection into the palatal bifurcation site of the first molar was repeated daily. The control groups (n = 8) were injected with rat serum albumin (10 micrograms), phosphate buffered saline (PBS), or were not injected. Tooth movement was evaluated daily by measuring the inter-cuspal distance between the first and the second molars on a precise plaster model. The cumulative tooth movement (mm) in the 1-microgram OC-injected groups was significantly more than that in all of the control groups on day 9. The rate of tooth movement (mm/day) showed periodical elevation, with high values on days 1, 4, 7, and 9. Acceleration of tooth movement by OC was significant in the early experimental period. Subsequently, acceleration of early tooth movement by OC was histologically evaluated (n = 40). Each of four animals from the control (PBS, n = 20) and the experimental (1 microgram OC, n = 20) groups was killed daily up to 5 days. A significantly larger number of osteoclasts accumulated on the mesial alveolar bone surface in the 1-microgram OC-injected group on day 3 than that observed in control group. These results suggest that administration of OC accelerates orthodontic tooth movement due to enhancement of osteoclastogenesis on the pressure side, primarily in the early experimental period.

Acid Phosphatase↗
PubMed2001

Protection of the photosynthetic apparatus against damage by excessive illumination in homoiohydric leaves and poikilohydric mosses and lichens.

Experimental work on the control of photosystem II in the photosynthetic apparatus of higher plants, mosses and lichens is reviewed on a background of current literature. Transmembrane proton transport during photoassimilatory and photorespiratory electron flows is considered insufficient for producing the intrathylakoid acidification necessary for control of photosystem II activity under excessive illumination. Oxygen reduction during the Mehler reaction is slow. Together with associated reactions (the water-water cycle), it poises the electron transport chain for coupled cyclic electron transport rather than acting as an efficient electron sink. Coupled electron transport not accompanied by ATP consumption in associated reactions provides the additional thylakoid acidification needed for the binding of zeaxanthin to a chlorophyll-containing thylakoid protein. This results in the formation of energy-dissipating traps in the antennae of photosystem II. Competition for energy capture decreases the activity of photosystem II. In hydrated mosses and lichens, but not in leaves of higher plants, protein protonation and zeaxanthin availability are fully sufficient for effective energy dissipation even when photosystem II reaction centres are open. In leaves, an additional light reaction is required, and energy dissipation occurs not only in the antennae but also in reaction centres. Loss of chlorophyll fluorescence during the drying of predarkened poikilohydric mosses and lichens indicates energy dissipation in the dry state which is unrelated to protonation and zeaxanthin availability. Excitation of photosystem II by sunlight is not destructive in these dry organisms, whereas photosystem II activity of dried leaves is rapidly lost under strong illumination.

Adaptation, Physiological↗