Defective Fas Expression on Bone Marrow Derived Cells Alters Atherosclerotic Plaque Morphology in Hyperlipidemic Mice.

Fas (CD95) is a member of the TNF-receptor family expressed on a wide range of cells. Interaction of Fas with its receptor, Fas ligand (Fas-L), stimulates an intracellular cascade of events that leads to apoptosis. Because apoptosis of inflammatory cells plays a key role in atherosclerosis we sought to determine the role of Fas in the development of atherosclerosis by repopulating the bone marrow cells of atherosclerosis-prone low density lipoprotein receptor null (LDL-R-/-) mice with either cells from lpr mice (lpr-BMT) that have defective Fas expression or from control mice (WT-BMT). The lpr-BMT mice exhibited no peripheral blood Fas expression 4 weeks after BMT. After consuming an atherogenic diet for 16 weeks, lpr-BMT mice developed atherosclerotic lesions characterized by smaller fibrous area with thinner fibrous cap and less TUNEL-positive staining compared to WT-BMT mice, although overall lesion size in lpr-BMT mice was similar to that of WT-BMT mice. Examination of a series of human atherosclerotic lesions revealed that many Fas-positive cells were colocalized with CD68-positive macrophages. Although apoptotic cells were rarely observed in the foam cell-rich fatty streak lesions, apoptotic CD68-positive macrophages in advanced lesions were detected in areas rich with inflammatory cells near the necrotic core. These observations suggest that Fas expression by the macrophages in atherosclerotic lesions can influence the plaque morphology towards a more fibrous type.

Self-assembly of HDL network on mica.

The structure of high-density lipoprotein (HDL) is a subject that continues to attract interest. The goal of this study is to observe the self-assembly construction of HDL on mica using atomic force microscopy (AFM). On mica, HDL was observed to form a honeycomb-like network formation. The narrowest part of the HDL wire was approximately 5.6 nm. HDL can be used in the microcircuitry of electronic devices and is of great interest in the field of nanotechnology.

[Laboratory examinations performed in rural practice].

Graduates from Jichi Medical School are obligated to work at rural clinics or hospitals, where most of them are the only medical doctor in the house. To understand how these graduates actually use laboratory examinations, what examinations they found most important in their practice, and when they were confident of their laboratory techniques, we designed a questionnaire to address these questions. Many respondents reported that their institutions had electrocardiographs, abdominal and/or cardiac ultrasonographs, urinalysis test paper, and portable blood glucose meters, and more than half of them reported having used these instruments without assistance in emergency situations. Moreover, a majority of the respondents said that they considered it important that a physician is able to use these instruments without the help of other staff members. Proficiency in many laboratory techniques was obtained and physicians were confident during their first postgraduate clinical practice. These responses clearly show the importance and usefulness of covering examination techniques and the principles of laboratory medicine in medical education and the first postgraduate clinical practice.

[Selection of appropriate antimicrobial agents to test and report by clinical microbiology laboratories].

Clinical microbiology laboratories in Japan have not yet established standards for selecting the most appropriate antimicrobial agents for testing and reporting antimicrobial susceptibility that are comparable to the performance standards of the National Committee for Clinical Laboratory Standards(NCCLS) in the United States of America. Selection of the most appropriate antimicrobial agents for testing and reporting was discussed by a working group(WG) consisting of medical physicians, surgeons, pharmacists, medical technologists and medical microbiologists. The WG agreed on the following basic criteria for the selection of antimicrobial agents: 1) the agent should be useful when screening various resistant bacteria, 2) the agent should serve as a useful guide for physicians and residents when selecting antimicrobial agents, and 3) the agent should be useful for controlling nosocomial infections and resistant bacteria. Clinically isolated microorganisms were classified into 7 groups based on susceptibility to antimicrobial agents. These groups were Staphylococcus spp. or Enterococcus spp., Streptococcus spp. or Haemophilus spp., enterobacteriae, glucose non-fermenting gram positive rods(NFRs), anaerobic bacteria, fungi and mycobacterium. After considering clinical and bacteriological evidence, the WG decided on several antimicrobial agents for testing in clinical microbiology laboratories in Jichi Medical School Hospital. For the NFR group, these were Piperacillin(PIPC), ceftazidime(CAZ), cefepime, imipenem, amikacin and levofloxacin(LVFX). For the enterobacteriae group, these were Amplicillin(ABPC), PIPC, aztreonam, CAZ and LVFX. For the Staphylococcus spp. or Enterococcus spp. group, these were oxacillin, ABPC, vancomycin and gentamicin. We concluded that the most appropriate antimicrobial agent for testing and reporting must be economical and agreed upon at the hospital level, although the ultimate selection must be based on the available clinical and bacteriological evidence.

Japanese familial hypercholesterolaemia with a 327insC mutation in the LDL receptor gene.

Mutations in the LDL receptor (LDLR) cause familial hypercholesterolaemia (FH) in an autosomal dominant manner. The condition frequently progresses to coronary atherosclerosis. We describe a patient with FH, but without ischaemic heart disease, who had a novel frameshift mutation (327insC) in exon 4 of the LDLR gene. This mutation introduced a premature termination codon (TGA, codon 158). The patient was a 59-year-old man who had presented with hypercholesterolaemia and a plasma total cholesterol (TC) concentration of 12.2 mmol/L at age 44 years. The mutation 327insC in this patient was heterozygous and hypercholesterolaemia was common within his family. Despite taking lipid-lowering medications (probucol and pravastatin) for more than 20 years, his TC concentration hardly fell below 7.8 mmol/L. However, neither the patient nor anyone else in his family developed characteristic symptoms of ischaemic heart disease or xanthoma. This patient was discovered by an intensive mutation survey among 22 unrelated Japanese with FH mainly in the Kanto area of Japan, suggesting a low incidence of the mutation in the area.

Afebrile scrub typhus (Tsutsugamushi disease) with acute respiratory distress syndrome.

A 74-year-old Japanese man with scrub typhus presented without the typical symptom of high fever and subsequently developed the complication of acute respiratory distress syndrome. It was suspected that exposure occurred at the river side of Kinugawa, Tochigi Prefecture, Japan. His body temperature was below 38.0 degrees C. After intensive supportive care and minocycline therapy, he dramatically recovered. With the increase in popularity of outdoor recreation, scrub typhus can be found in clinics all over Japan. Physicians should therefore be aware of the manifestations of the disease and the necessity of early treatment in suspected cases.

Overexpression of interleukin-10 by activated T lymphocytes inhibits atherosclerosis in LDL receptor-deficient Mice by altering lymphocyte and macrophage phenotypes.

Previous studies demonstrated that interleukin-10 (IL-10) overexpression decreases formation of early fatty-streak lesions in mice independent of lipoprotein levels. The present studies, using bone marrow transplantation, demonstrate that overexpression of IL-10 by T cells inhibits advanced atherosclerotic lesions in LDL receptor-null mice fed an atherogenic diet. In mice receiving bone marrow from the IL-10 transgenic mice compared with those receiving wild-type marrow, there was a 47% decrease in lesion size and a marked decrease in lesion complexity with an 80% reduction in the necrotic core. Accumulation of cholesterol and phospholipid oxidation products in the aorta was decreased by 50% to 80%, unrelated to plasma lipid or IL-10 levels. Our studies also provide insight into the mechanism of the IL-10-mediated decrease in lesion size. Although a strong influence toward a Th1 phenotype has previously been demonstrated in atherosclerotic models, T lymphocytes in the IL-10 transgenic (Tg) group revealed a marked shift to a Th2 phenotype, with decreased IFN-gamma production and an increase in IL-10. Evaluation of specific immunoglobulin subclasses demonstrated a preponderance of IgG(1) isotype, characteristic of a Th2 influence on B cell immunoglobulin class-switching in the IL-10 Tg group. A major finding of these studies was altered monocyte/macrophage function in the IL-10 Tg group. Monocytes showed a decrease in activation resulting in decreased expression of IFN-gamma. Furthermore, macrophage foam cells within lesions of the IL-10 Tg group exhibited markedly decreased apoptosis. These studies demonstrate that T lymphocyte IL-10 can influence the function of other immune cells to reduce the development of advanced atherosclerotic lesions in mice.