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Biomedical subjects

M Yanai

Publications and source records attributed to M Yanai.

At least 37 records · Page 2Linked to original sources
PubMed2000

Water content and thickness of the stratum corneum contribute to skin surface morphology.

Skin surface morphology has long been recognized as reflecting skin pathology. In the present study, we evaluated skin surface morphology using hairless mice under contrasting conditions of humidity. The skin surface microrelief was recorded with opaque quick-drying silicone rubber, and examined under a microscope. A binary image was produced by density slicing. Within 3 days of exposure to dry conditions, skin roughness was significantly increased. The skin roughness was partially mitigated by topical application of an aqueous solution of glycerol or hydration by immersion in water. A significant correlation between skin roughness and stratum corneum thickness was also observed. These results suggest that skin surface morphology is associated with both water content and thickness of the stratum corneum.

Administration, Topical↗
PubMed2000

Phylogenetic evidence, by multiple clone analysis of hypervariable region 1, for the transmission of hepatitis C virus to chronic haemodialysis patients.

We analysed hepatitis C virus (HCV) sequences to determine whether nosocomial transmission of HCV occurred in a haemodialysis unit. Twenty patients positive for serum HCV RNA were investigated. All were undergoing haemodialysis therapy in the same room. The hypervariable region 1 (HVR1) sequence of HCV was amplified and multiple clones sequenced. Phylogenetic analysis of these sequences revealed five genetic clusters consisting of HCV isolates from 11 of the 20 patients. In addition to two genetic clusters of HCV isolates from the four currently seroconverting patients and another patient who had been persistently infected, we identified three other phylogenetic relationships in HCV isolates from six patients. The patients grouped into the same cluster received haemodialysis individually on the same shift and/or side-by-side. Phylogenetic analysis of HCV HVR1 sequences corroborated the patient-to-patient HCV transmission suggested by an epidemiological study and that unrecognized transmission of HCV occurs in the dialysis room. Our multiple clone analysis of HCV isolates provides detailed information on nosocomial transmission of HCV. Transmission occurs more frequently when treatment is performed at the same time than in consoles located close to each other.

Adult↗
PubMed2000

Physical model-based indirect measurements of blood pressure and flow using a centrifugal pump.

This article describes a technique offering indirect measurements of pump pressure differential and flow with certain accuracy independent of changes in blood viscosity. This technique is based on noninvasive measurements of the motor current and rotation speed using the physical model equations of the centrifugal pump system. Blood viscosity included in the coefficients of the dynamic equations is first estimated, and then substitution of the estimated viscosity into the steady equations of the model provides pump flow and pressure differential. In vitro tests using a Capiox pump showed a sufficient linear correlation between actual values and their estimates for pressure differential and pump flow. An in vivo test using a 45 kg sheep showed that the proposed algorithm needs robustness for the convergence of estimates of viscosity. An overall evaluation, however, of the developed algorithm/model showed indications of success in terms of efficient computation and modeling.

Algorithms↗
PubMed2000

Occasional infection of hepatitis C virus occurring in haemodialysis units identified by serial monitoring of the virus infection.

To examine whether hepatitis C virus (HCV) infection still occurs in haemodialysis units even after a decrease in the number of blood transfusions and in those contaminated with HCV, we tested anti-HCV antibodies and HCV RNA in 142 patients from Japanese haemodialysis units, and examined the serial prevalence of anti-HCV antibodies in 86 patients from 1992 to 1997. A high prevalence of HCV infection was observed: 34 (23.9%) and 38 (26.8%) of the 142 patients were positive for serum anti-HCV antibodies and HCV RNA, respectively. These positive rates were related to the duration of haemodialysis. We found that five patients treated in the same unit seroconverted from 1993 to 1995. Four of the five patients had been treated at the same shift and were affected at the same time. Phylogenetic analysis of the hypervariable region 1 (HVR1) sequence of HCV from serum of these patients showed that three of the four patients' sequences were phylogenetically clustered and that two of the three were closely related. Thus, an occasional transmission of HCV occurred in the haemodialysis unit. The universal precautions by staff such as carefully changing gloves may be important in inhibiting spread of HCV because no instances of infection have been seen since the instigation of educational measures for unit staff.

Adult↗
PubMed2000

Cyclooxygenase-2-dependent prostaglandin production by peripheral blood monocytes stimulated with lipopolysaccharides isolated from periodontopathogenic bacteria.

BACKGROUND: Prostaglandin E2 (PGE2) plays important roles in the pathogenesis of periodontal disease. Recent studies have revealed the existence of 2 isozymes of cyclooxygenase (COX), called COX-1 and COX-2. The purpose of the present study was to investigate the contribution of COX-1 and COX-2 to PGE2 production by human peripheral blood monocytes that are stimulated with lipopolysaccharides (LPS) from periodontopathogenic bacteria. METHODS: LPS were isolated from Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) and Porphyromonas gingivalis (P. gingivalis) by the phenol-water method. Peripheral blood monocytes were stimulated with LPS for the indicated periods, and the levels of PGE2 or interleukin (IL)-1 beta in the culture media were measured by enzyme-linked immunosorbent assay. Expression of COX-1 and -2 proteins was studied by immunocytochemical staining, and COX-2 mRNA expression was examined by Northern blot analysis. RESULTS: Peripheral blood monocytes stimulated with A. actinomycetemcomitans- or P. gingivalis-LPS produced PGE2 in a time- and dose-dependent manner. Indomethacin, a non-selective COX-1/COX-2 inhibitor, and NS-398, a specific COX-2 inhibitor, completely inhibited PGE2 production. Immunocytochemical staining of COX-1 and COX-2 proteins showed that expression of COX-2 protein was increased in monocytes that were stimulated with A. actinomycetemcomitans- or P. gingivalis-LPS, compared with that in unstimulated monocytes, whereas expression of COX-1 protein was not altered. Northern blot analysis showed that monocytes stimulated with A. actinomycetemcomitans- or P. gingivalis-LPS expressed COX-2 mRNA, while COX-2 mRNA was not detectable in unstimulated cells. Treatment of A. actinomycetemcomitans-LPS-stimulated monocytes with NS-398 induced a significant increase of IL-1 beta production to the same extent as treatment with indomethacin. CONCLUSIONS: These results suggest that COX-2 is induced in monocytes stimulated with LPS derived from A. actinomycetemcomitans and P. gingivalis and that the COX-2 is primarily responsible for PGE2 production. COX-2 may be pivotal in PGE2 production in periodontal lesions and may be involved in inflammatory responses.

Aggregatibacter actinomycetemcomitans↗
PubMed2000

Synthesis of N-4909 analogs. Part I. A stimulant of apolipoprotein E secretion in human hepatoma G2 cells.

Analogs of N-4909 (1), which had a stimulating activity for apolipoprotein E (apo E) secretion in Human hepatoma Hep G2 cells, were prepared and their activities examined. Cyclic analogs which had different kinds of amino acids or different number of amino acids from N-4909 (1) showed less effect on apo E secretion from Hep G2 cells. The length of acyl chain was found to be an important factor for the activity. Shorter chain reduced the activity. Linear analogs were also prepared. One of their analogs, N-5849 (17), which had six amino acids was found to have strong activity.

Apolipoproteins E↗
PubMed2000

Functional and morphological studies of photodamaged skin on the hands of middle-aged Japanese golfers.

The skin of golfers' hands provides a suitable model to study the effect of chronic sun exposure, because one of their hands is exposed to the outer environment, especially sunlight, while the other one is always protected by a glove during play. Our purpose was to find out the influence of photodamage on the properties of the skin surface of middle-aged Japanese by using non-invasive methods. We measured hydration state, and water barrier function of the stratum corneum (SC) and the color of the skin of the dorsum of the hands. In a separate study, we evaluated the skin surface contour by using replicas taken from the skin in a slightly stretched or relaxed position. We found a significant decrease in hydration of the skin surface of the exposed skin as compared to that of the protected skin, whereas no such difference was found with transepidermal water loss, a parameter for water barrier function of the SC. Luminance of skin color was also reduced in the sun-exposed skin. Replica analysis revealed that large wrinkles developing in a relaxed position were more prominent on the exposed than on the protected skin, while fine furrows noted in a slightly stretched position were shallower on the former than the latter. The data obtained indicate that the chronically exposed skin of golfers' hands shows morphological and functional changes resulting from long time exposure to the outer environment especially sunlight. Furthermore, bioengineering non-invasive methods are found to be useful to detect early photodamage of the skin in a more quantitative fashion which is rather difficult to demonstrate clinically.

Biophysics↗
PubMed2000

A study on task-analysis of clinical pathologists as medical consultants in Nihon University Hospital--a Japanese perspective by comparison with current status in the USA.

To identify our role and the customers' satisfaction, the on-call consultation service records of the Department of Clinical Pathology, Nihon University School of Medicine, Itabashi Hospital (NUIH), were analyzed. Between 1995 and 1998, 1,789 consultation services were recorded, and approximately 40% were from physicians, and 50% were from medical technologists. During office hours, many physicians made contact with us at the office of clinical pathology, the clinical laboratory and other places in the hospital by various means. They asked us to interpret multidisciplinary laboratory data, and to provide the specific information that might affect clinical management. Medical technologists asked for clinical information of patients with extreme measured values and requested that we contact with physicians. In contrast, on weekends/holidays or after routine working hours, physicians sometimes requested non-automated laboratory tests such as peripheral blood smears/bone marrow smears or Gram stains. The major contents of our responses to medical technologists were concerned with blood banking and handling of instruments not to be operated in routine work. These results reconfirm that we are still required to have clinical competence for common laboratory procedures and to have the capability of interpretation of multidisciplinary laboratory data in the university hospital. Traditionally, most Japanese clinical pathologists have been focused their attention on bench work in research laboratories. However, the present study shows that the clinical pathologists need to bridge the real gap between laboratory technology and patient care. Our on-call service system can enhance the education of clinical pathologists, and improve not only laboratory quality assurance but also patient care. In addition, in response to a need for customer access to this service with a shortage of clinical pathologists, a more effective method would be to set up a proactive systemic approach in a more rigorous academic environment adopting advances in medical informatics.

Consultants↗
PubMed2000

[Analysis of on-call consultations with clinical pathologists--identification of customer's satisfaction].

One aspect whereby effectiveness of clinical pathologists can be measured is customer service and satisfaction. Clinical pathologist should identify their customers, their processes and procedures to meet these needs to the customer's satisfaction. To identify customer's satisfaction, the records of on-call consultations with clinical pathologists were analyzed. Between January 1996 and December 1998, 1327 consultations were recorded, 40% of which were consultations from physicians, 50% from medical technologists. Physicians requested interpretation of laboratory data obtained, and clinical knowledge mainly concerning the microbiology and hematology during office hours. On holidays, physicians needed help performing emergency tests such as Gram stain and Wright-Giemsa stain. During office hours, medical technologists requested clinical information concerning patients in whom unreasonable data would be reported and the contact to the clinical side. Furthermore, technologists inquired about the methodology of laboratory tests during day duty on holidays. These results indicated that the clinical pathologist in our hospital could satisfy the customer(physicians and medical technologists), by providing 1) a wide range of clinical knowledge concerning not only the laboratory medicine but clinical medicine including therapeutics, 2) capability of performing emergency tests such as Gram stain and Wright-Giemsa stain, and 3) capability of interpreting the results obtained. Although these would not be adopted in every hospital, every clinical pathologist should examine his role in the hospital.

Consumer Behavior↗
PubMed1999

Production and secretion of adrenomedullin in cultured human alveolar macrophages.

To explore the role of adrenomedullin (ADM) in macrophages, we investigated the secretion of ADM by alveolar macrophages. Human alveolar macrophages obtained from bronchoalveolar lavage were cultured for 24 h. Northern blot analysis revealed ADM mRNA expression in alveolar macrophages. The levels of immunoreactive ADM in the media were 0.89+/-0.12 fmol/10(5) cells/24 h (n = 10). Reverse-phase high-performance liquid chromatography of the extract of culture media showed one major peak eluting in the position of the human ADM standard. The present study shows that alveolar macrophages produce and secrete ADM.

Adrenomedullin↗
PubMed1999

[Two cases of pasteurellosis accompanied by exudate with semen-like odor from the wound].

We encountered two cases of Pasteurella multocida subsp. septica isolation from exudates with seminal fluid-like odor from dog scratch and cat bite. Case 1: A 78-year-old male who had been diagnosed as having diabetes mellitus five years ago was scratched by the claw of a pet dog (Pekinese) on the back of the right hand. Since inflammation ascended to the arm, the patient visited Nihon University Itabashi hospital for a medical examination. Case 2: A 51-year-old female without a specific past history other than hyperlipidemia was bitten by a pet cat at the medical and lateral sides of the left carpus. The patient immediately opened the wound and washed it with tap water, followed by disinfection using a non-iodine disinfectant at home. Two hours later, the patient felt an unpleasant sensation and smelled a seminal fluid-like odor at the wound. The next morning, the entire left arm swelled and pain worsened, then the patient sought medical attention. The patients were treated with antibiotics and the wound completely healed on the 16 days from on set in Case 1 and on the 10 days from onset in Case 2. From these two cases, Pasteurella multocida subsp. septica was isolated from the exudate, suggesting that when wounds caused by animals smell like seminal fluid, the wound is infected with Pasteurellae. This finding may be an important clue for differentiation in clinical diagnosis.

Aged↗
PubMed1999

Intracellular elasticity and viscosity in the body, leading, and trailing regions of locomoting neutrophils.

To investigate the mechanisms underlying pseudopod protrusion in locomoting neutrophils, we measured the intracellular stiffness and viscosity in the leading region, main body, and trailing region from displacements of oscillating intracellular granules driven with an optical trap. Experiments were done in control conditions and after treatment with cytochalasin D or nocodazole. We found 1) in the body and trailing region, the granules divided into a "fixed" population (too stiff to measure) and a "free" population (easily oscillated; fixed fraction 65%, free fraction 35%). By contrast, the fixed fraction in the leading region was <5%. 2) In the body and trailing region, there was no difference in stiffness or viscosity, but both were sharply lower in the leading region (respectively, 20-fold and 5-fold). 3) Neither cytochalasin D nor nocodazole caused a decrease in stiffness, but both treatments markedly reduced the fixed fraction in the body and trailing region to <20% and <40%, respectively. These observations suggest a discrete lattice structure in the body and trailing region and suggest that the developing pseudopod has a core that is more fluidlike, in the sense of a much lower viscosity and an almost total loss of stiffness. This is consistent with the contraction/solation hypothesis of pseudopodial formation.

Cell Movement↗
PubMed1999

First total synthesis of N-4909 and its diastereomer; a stimulant of apolipoprotein E secretion in human hepatoma Hep G2 cells.

Both (R)- and (S)-3-hydroxy-13-methyltetradecanoic acids were prepared via a lipase-catalyzed enantioselective acylation. The total synthesis of N-4909 and its diastereomer were achieved by a coupling of either (R)- or (S)-3-hydroxy-13-methyltetradecanoic acid moiety with a hexapeptide moiety and by a cyclization with HATU (O-(7-azabenzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate) and HOAt (1-hydroxy-7-azabenzotriazole) in a high dilution condition. The R configuration of 3-hydroxy-13-methyltetradecanoic acid was found to be important for stimulating the activity of apolipoprotein E secretion in human hepatoma Hep G2 cells.

Animals↗