Microdetermination of the prostaglandin B1 in human plasma by gas chromatography/selected ion monitoring using [18O]prostaglandin B1 as an internal standard

We devised a simple and effective purification for the microdetermination of prostaglandin B1 (PGB1), a metabolite of PGE1. [18O]PGB1 was synthesized by the repeated base-catalyzed hydrolysis of methyl ester derivatives in H(2)18O, to obtain an internal standard for the gas chromatography/selected ion monitoring (GC/SIM) of PGB1. The methyl ester-methoxime-dimethylisopropylsilyl ether derivative was prepared, then GC/SIM was carried out by monitoring the ion at m/z 448.3 for PGB1 and that at m/z 452.3 for internal standard. A good linear response over the range of 10 pg to 100 ng was demonstrated. We detected PGB1 to a level of about 40 pg/mL in human plasma. This method can be used to determine PGB1 in biological samples.

Small Maf proteins heterodimerize with Fos and may act as competitive repressors of the NF-E2 transcription factor

The maf oncogene encodes a bZip nuclear protein which recognizes sequences related to an AP-1 site either as a homodimer or as heterodimers with Fos and Jun. We describe here a novel maf-related gene, mafG, which shows extensive homology with two other maf-related genes, mafK and mafF. These three maf-related genes encode small basic-leucine zipper proteins lacking the trans-activator domain of v-Maf. Bacterially expressed small Maf proteins bind to DNA as homodimers with a sequence recognition profile that is virtually identical to that of v-Maf. As we have previously described, the three small Maf proteins also dimerize with the large subunit of NF-E2 (p45) to form an erythroid cell-specific transcription factor, NF-E2, which has distinct DNA-binding specificity. This study shows that the small Maf proteins can also dimerize among themselves and with Fos and a newly identified p45-related molecule (Ech) but not with v-Maf or Jun. Although the small Maf proteins preferentially recognize the consensus NF-E2 sequence as heterodimers with either NF-E2 p45, Ech, or Fos, these heterodimers seemed to be different in their transactivation potentials. Coexpression of Fos and small Mafs could not activate a promoter with tandem repeats of the NF-E2 site. These results raise the possibility that tissue-specific gene expression and differentiation of erythroid cells are regulated by competition among Fos, NF-E2 p45, and Ech for small Maf proteins and for binding sites.

Preferential reduction of nm23-H1 gene product in metastatic tissues from papillary and follicular carcinomas of the thyroid

The nm23 gene product is a possible mediator of cancer invasion and metastasis, and has been divided into two distinct gene products, NM23-H1 and NM23-H2. It has been shown previously that expression of nm23-H1 messenger RNA is reduced in metastatic lymph nodes from patients with papillary carcinoma of the thyroid (Am J Pathol 142:1938-1944, 1993). Since mAb H1-229 specific for NM23-H1 is now available, we further extended our study to examine the expression of nm23-H1 gene product in various types of thyroid cancer (37 cases of papillary carcinoma, 42 cases of follicular carcinoma, 17 cases of anaplastic carcinoma, and 3 cases of medullary carcinoma). NM23-H1 was expressed in primary papillary and follicular carcinomas (14/15 and 21/22), but weakly or hardly expressed in metastatic lymph nodes and metastatic bone marrow (6/23 and 1/4) (P < 0.01). Expression of NM23-H1 was low or absent in anaplastic and medullary carcinoma (3/17 and 0/3) (P < 0.01).

Water content in experimental dentine primers to minimize the contraction gap width of a light-cured resin composite

OBJECTIVES

The effect of water content in experimental dentine primers consisting of an aqueous solution of either glyceryl methacrylate (GM) or hydroxyethyl methacrylate (HEMA), and in experimental self-etching dentine primers composed of methacryloxyethyl hydrogen phenyl phosphate (Phenyl-P), was evaluated by measuring the wall-to-wall polymerization contraction gap width of a commercial light-activated resin composite filled in a cylindrical dentine cavity prepared in an extracted human molar.

METHODS

A commercial light-cured dentine bonding agent was applied to the cavity after cleaning with EDTA and priming with either GM or HEMA, or after self-etching priming by Phenyl-P diluted in either GM or HEMA solution.

RESULTS

In the GM and HEMA solutions, the gap width was minimized when the water content was 65 wt% even though gap formation could not be prevented by HEMA solution. With the self-etching dentine primers, gaps could not be observed under the light microscope with 16 wt% Phenyl-P diluted in 35 wt% GM or HEMA or with 20 wt% Phenyl-P diluted in 20 wt% GM or HEMA.

CONCLUSION

The water content in both the experimental dentine primers and the self-etching dentine primers which yielded the minimum contraction gap width for the resin composite in the dentine cavity was approximately 60 wt%.

Activity and expression of murine small Maf family protein MafK

Transcription factor NF-E2 is believed to be crucial for the regulation of erythroid-specific gene transcription. The three small Maf family proteins (MafF, MafG, and MafK), which are closely related to c-Maf proto-oncoprotein, constitute half of NF-E2 activity by virtue of forming heterodimers with the large, tissue-restricted subunit of NF-E2 (p45). We isolated cDNA clones encoding the murine small Maf family protein MafK and characterized the structure, activity, and expression profile of MafK mRNA. Functional analyses demonstrate that MafK binds to consensus NF-E2 sites in the absence of p45 in vitro and represses transcription of NF-E2 site-dependent reporter genes in transient transfection assays, while p45 introduced into cells alone does not effectively bind to DNA and does not affect transcription. In the presence of p45, MafK confers site-specific DNA binding activity to p45, and p45 in turn mediates transcriptional activation with its amino-terminal proline-rich domain. mRNA for MafK is expressed in fractions enriched for hematopoietic stem cells as well as erythroid cells, suggesting that MafK plays an important regulatory role in hematopoiesis.

Incoherent-only joint-transform correlator

An incoherent-only optical and electronic digital joint-transform correlator is proposed. A technique for the removal of extraneous signals inherent in the incoherent-only joint-transform correlator is also presented. A computer simulation and experimental results confirm the performance of the proposed incoherent-only joint-transform correlator.

Gq pathway desensitizes chemotactic receptor-induced calcium signaling via inositol trisphosphate receptor down-regulation

Desensitization of a chemotactic receptor is an adaptive process that terminates inflammation. Although homologous desensitization can be well explained by the action of specific receptor kinases, the mechanisms of heterologous desensitization remain elusive. As an approach to evaluate the roles of Gq pathway in desensitization of calcium signaling, we expressed a constitutively active Gq alpha mutant (Gq alpha Q-L) together with platelet-activating factor (PAF) receptor in Xenopus laevis oocytes. Gq alpha Q-L expression completely attenuated the calcium-sensitive chloride current and the 45Ca release elicited by PAF. The Gq-mediated desensitization could not be ascribed to G protein/receptor uncoupling via receptor phosphorylation, because (i) PAF-induced inositol 1,4,5-trisphosphate (IP3) synthesis was only partially suppressed and (ii) a mutated PAF receptor devoid of all Ser and Thr in the third cytoplasmic loop and in the C-terminal tail was also completely desensitized by Gq alpha Q-L. In Gq alpha Q-L expressing oocytes, microinjection of IP3 failed to elicit the calcium response, and the IP3 receptor, detected by a specific antibody, disappeared. Thus, the Gq-mediated desensitization can be most likely explained by IP3 receptor down-regulation. These novel mechanisms may explain in part heterologous desensitization in chemotactic factor-stimulated inflammatory cells.

Effects of hypobaric hypoxia on histochemical fibre-type composition and myosin heavy chain isoform component in the rat soleus muscle

Histochemical fibre-type composition and myosin heavy chain isoform component in the soleus muscle were studied in normoxic rats at postnatal ages of 5, 10, 15, and 20 weeks and in rats exposed to hypobaric hypoxia (460 torr) for 5 weeks from postnatal ages of 5, 10, and 15 weeks. The increase in the percentage of type I fibres and the concomitant decrease in that of type IIa fibres in the soleus muscle of normoxic rats were observed until 15 weeks of age. On the other hand, no change in the fibre-type composition of the muscle during postnatal development was observed in hypoxic rats, irrespective of the age at which they were exposed to hypoxia. The changes in the myosin heavy chain isoform component (MHC I and MHC IIa) of the muscle during postnatal development and by hypoxia corresponded well with those in the muscle fibre-type composition. It is concluded that hypobaric hypoxia inhibits the growth-related shift of muscle fibre-types from type IIa to type I and of myosin heavy chain isoforms from MHC IIa to MHC I in the rat soleus muscle, and that there are no changes in the muscle fibre-type composition or the myosin heavy chain isoform component caused by hypoxia after the shifts in these parameters which occur during postnatal development are completed.

Detection of alpha- and beta-hemolytic-like activity from Campylobacter jejuni

Alpha-hemolytic-like activity from Campylobacter jejuni was clearly apparent when the medium pH ranged from 6.0 to 6.5, but the hemolytic zones disappeared when the pH of the medium increased. Beta-hemolytic-like activity just beneath the bacterial growth appeared after prolonged incubation. The hemolytic activity was not influenced by the species of blood.

Induction of L1 mRNA in PC12 cells by NGF is modulated by cell-cell contact and does not require the high-affinity NGF receptor

We examined the effects of nerve growth factor (NGF) and cell-cell contact on expression of the neural cell adhesion molecule L1 in PC12 cells. After 7 d exposure to NGF, but not after exposure to EGF, FGF, TGF beta, or dibutyryl cAMP (dbcAMP), L1 mRNA levels increased fourfold. This increase was not blocked by K252a, an inhibitor of the high-affinity NGF receptor, although neurite extension was completely inhibited. L1 mRNA levels also increased in NGF-treated mutant PC12 cells (PC12nnr5) that lack the high-affinity NGF receptor. The effect of NGF on L1 mRNA was greatest in cells cultured at high density, but its effect on cells cultured at low density was augmented by antibody to L1 (to mimic L1 homophilic binding). Various extracellular matrix components had no differential effects on L1 mRNA levels in either the presence or absence of NGF. Together, these findings suggest that NGF regulates L1 expression by a mechanism that is independent of the high-affinity NGF receptor and that this regulation is modulated by cell-cell contact but not by cell-extracellular matrix interactions.

CNS myelinogenesis in vitro: time course and pattern of rat oligodendrocyte development

Oligodendrocyte precursor cells that develop into myelin-forming cells of the central nervous system (CNS) were cultured from newborn rat brain to study how they proliferate and differentiate in normal conditioning medium, and their cell development was characterized by scanning electron microscopy (SEM) observation and immunocytochemical studies. We have identified A2B5-negative pre-O2A progenitor cells (so-called "type-1" oligodendrocytes) in the secondary cultures on the astrocyte feeder layer. These cells are very small (diameter: 3.5 microns), round, and glossy, and develop into the process-bearing O2A progenitor cells (called "type-2" oligodendrocytes), which also express myelin basic protein (MBP) both in the cell body and in their cell processes. Finally, they develop into mature oligodendrocytes (called "type-3" oligodendrocytes). After MBP expression is elicited in these cells and MBP accumulates in the cell process in the area in contact with the axon, these cells are capable of forming the myelin sheath. Therefore, we examined the mechanism of myelin-sheath formation of "type-3" oligodendrocytes using video time-lapse movies, and demonstrated that these cells initially sent out processes to search for axons several times before the onset of myelination. Then thick filopodia extended towards the axon, and at the same time, the axonal part of neuron moved forward. Finally the ruffling lamellipodial parts wrapped up the axon similarly to a transverse wave with the secured thick filopodial process on the axon acting as scaffolding. These results suggest that our experimental systems are useful in studying normal oligodendrocyte development and their cellular biochemistry, as well as investigating the mechanism of myelin formation by oligodendrocytes.

Optically active antifungal azoles. IV. Synthesis and antifungal activity of (2R,3R)-3-azolyl-2-(substituted phenyl)-1-(1H-1,2,4-triazol-1-yl)-2-butanols

(2R,3R)-3-Azolyl-2-(substituted phenyl)-1-(1H-1,2,4-triazol-1-yl)-2-butanols (III) were prepared from (2R,3S)-3-methyl-2-(substituted phenyl)-2-(1H-1,2,4-triazol-1-yl)methyloxiranes (21a-f) by a ring-opening reaction with 1H-1,2,3-triazole and 1H-tetrazole and evaluated for antifungal activity against Candida albicans in vitro and in vivo. The optically active oxiranes (21a--f) which serve as the key synthetic intermediates, were synthesized from 1-[(2R)-2-(3,4,5,6-tetrahydro-2H-pyran-2-yl)oxypropanoyl]morpholin e (24) and substituted phenylmagnesium bromide (23) via six steps in a stereocontrolled manner. The 3-(1H-1,2,3,-triazol-1-yl)-(IIIa) and 3-(2H-2-tetrazolyl)-2-butanol (IIId) derivatives showed strong protective effects against candidosis in mice.

[Primary culture of proximal tubular cells (PTC) from normal mouse kidney as an in vitro model to study mechanisms of development of tubulointerstitial nephritis. Induction of ICAM-1 in PTC by antigen-primed lymphocytes]

Cultured PTC clearly expressed intercellular adhesion molecule-1 (ICAM-1) under the influence of tubular basement membrane antigen (TBM)-primed lymphocytes. These TBM-primed lymphocytes also demonstrated a high cytotoxic activity against cultured PTC. A pure preparation of isolated PTC from BALB/c mouse kidney was brought into primary culture. PTC was prepared by the method of Boogaard PJ et al, and our modification. Briefly, kidney was perfused with buffer containing 0.08% (w/v) collagenase. The cortical tissue was then filtered through nylon-gauze. Viable PTC were separated from other materials by isopycnic centrifugation on a discontinuous Nycodenz gradient. The confluent monolayer of PTC showed a typical epithelial morphology with cobblestone-like cells in the center of the cell-islands. Typical dome formation was observed in PTC cultures. These cells also strongly expressed gamma-glutamyl transpeptitase activity. Coculture of PTC with syngeneic lymphocytes primed with TBM antigen induced ICAM-1 expression in PTC. The TBM-primed lymphocytes had a cytotoxic activity without complement. However, neither virgin lymphocytes nor liver antigen-primed lymphocytes had cytotoxic activity. This simple syngeneic experimental model may allow us further molecular biological examination of renal tubulointerstitial diseases.

Optically active antifungal azoles. V. Synthesis and antifungal activity of stereoisomers of 3-azolyl-2-(substituted phenyl)-1-(1H-1,2,4-triazol-1-yl)-2- butanols

The (2S,3S)-, (2R,3S)- and (2S,3R)-stereoisomers of (2R,3R)-3-azolyl-2-(substituted phenyl)-1-(1H-1,2,4-triazol-1-yl)-2-butanols [(2R,3R)-1a--d] were prepared and evaluated for antifungal activity against Candida albicans in vitro and in vivo to clarify the relationships between stereochemistry and biological activities. The results revealed that the in vitro antifungal activity in each set of the four stereoisomers [(2R,3R)-, (2S,3S)-, (2R,3S)- and (2S,3R)-1a--d] definitely paralleled the in vivo antifungal activity against candidosis in mice, and the order of potency was (2R,3R) >> (2R,3S) > or = (2S,3S) > or = (2S,3R). In addition, the four stereoisomers in each set were assessed for sterol biosynthesis-inhibitory activities in C. albicans and rat liver. The (2R,3R)-isomer was found to exert a strong and selective inhibitory effect on the sterol synthesis in C. albicans as compared with that in rat liver.

Effects of hypophysectomy on soleus muscle fibers and spinal motoneurons in rats

The fiber type distribution of the soleus muscle in male and female rats was investigated 4 weeks after hypophysectomy. Oxidative enzyme activity of the soleus motoneurons in the spinal cord was also examined by enzyme histochemical assay. In male rats, the total number of fibers in the soleus muscle was not changed after hypophysectomy, but the percentage of intermediate (INT) fibers (with intermediate adenosine triphosphatase activity following alkaline preincubation, and high succinate dehydrogenase and alpha-glycerophosphate dehydrogenase activities) was increased. All types of fibers in the soleus muscle of hypophysectomized rats showed high adenosine triphosphatase activity following acid preincubation. Oxidative enzyme activity of the motoneurons innervating the soleus muscle was not changed after hypophysectomy. Similar results were obtained in female rats. It is suggested that the increased percentage of INT fibers in the rat soleus muscle after hypophysectomy is due to a lack or reduced levels of growth hormones, and that the metabolic capacities of the muscle fibers and of the innervating motoneurons are affected independently by hypophysectomy.

Antigenicities of enteropathogenic Escherichia coli, lysozyme, and alpha-1-antichymotrypsin on macrophages of genitourinary malacoplakia

Seven cases of genito-urinary malacoplakia were analyzed histologically, ultrastructurally and immunohistochemically in a comparison with two cases of xanthogranulomatous pyelonephritis. Immunohistochemically, von Hansemann cells and Michaelis-Guttmann bodies, both hallmarks for the diagnosis of malacoplakia, showed a common antigenicity for enteropathogenic Escherichia coli as cytoplasmic granules of varying sizes. These microscopic manifestations corresponded ultrastructurally to a series of phagolysosomal degradations of coliform bacilli. Serogroups against E. coli OK antigens, which were positive for malacoplakic cells, were not confined to a particular group. Macrophages of xanthogranulomatous pyelonephritis did not show the E. coli antigenicity. Antigenicity of lysozyme and alpha-1-antichymotrypsin on the von Hansemann cells was equivocal, but these enzymes were strongly positive on macrophages of xanthogranulomatous pyelonephritis. The macrophages of both malacoplakia and xanthogranulomatous pyelonephritis were positive for antihuman macrophage antibody. These results indicate that malacoplakia depends mainly on infection by a non-specific strain of enteropathogenic E. coli and may arise from defective digestive enzyme activity of infiltrating macrophages. Immunohistochemical analysis using antisera against E. coli OK antigens, lysozyme and alpha-1-antichymotrypsin was useful in identifying the prediagnostic stage of malacoplakia and in differentiating the lesion from xanthogranulomatous pyelonephritis.

Immunopathological mechanisms of human T cell lymphotropic virus type 1 (HTLV-I) uveitis. Detection of HTLV-I-infected T cells in the eye and their constitutive cytokine production

The immunopathology of human T cell lymphotropic virus type 1 (HTLV-I) uveitis was addressed by using T cell clones (TCC) established from the intraocular fluid of patients with HTLV-I uveitis. Proviral DNA of HTLV-I was identified in 55 out of 94 (59%) or 13 out of 36 (36%) TCC from the ocular fluid or the peripheral blood of these patients, respectively. Most of HTLV-I-infected TCC had a CD3+ CD4+ CD8- phenotype. HTLV-I infection on TCC was confirmed by analysis of the viral mRNA, nucleotide sequence, virus-associated proteins, and virus particles. HTLV-I-infected TCC, but not HTLV-I negative TCC, constitutively produced high amounts of IL-6 (1,336 +/- 1,050 pg/ml) and TNF-alpha (289 +/- 237 pg/ml) in the absence of any stimuli. HTLV-I-infected TCC from the ocular lesion also constitutively produced high amounts of IL-1 alpha (12,699 pg/ml), IL-2 (61 pg/ml), IL-3 (428 pg/ml), IL-8 (1,268 pg/ml), IL-10 (28 pg/ml), IFN-gamma (5,095 pg/ml), and GM-CSF (2,886 pg/ml). Hydrocortisone, a drug effective in vivo for the treatment of HTLV-I uveitis, severely depressed cytokine production in vitro in most cases. In summary, the results demonstrated direct evidence of HTLV-I infection of the eye and suggest that cytokines produced by HTLV-I-infected T cells are responsible for the intraocular inflammation in patients with HTLV-I uveitis.

CT finding of transient focal increased attenuation of the liver adjacent to the gallbladder in acute cholecystitis

OBJECTIVE

The purpose of this article is to report the finding of transient focal increased attenuation of the liver adjacent to the gallbladder on enhanced CT scans in patients with acute cholecystitis. This finding should not be confused with primary liver abnormalities.

MATERIALS AND METHODS

Five patients with acute cholecystitis were studied. Because a thickened gallbladder wall was seen on sonography, all patients were examined preoperatively with incremental dynamic helical CT to exclude carcinoma of the gallbladder. CT findings were compared with results of sonography for five patients, MR imaging for two patients, and surgery for five patients.

RESULTS

Transient focal increased attenuation of the liver adjacent to the gallbladder was seen in the early phase of incremental dynamic CT in five patients and extended into the medial segment anterior to the porta hepatis. The areas showing increased attenuation adjacent to the gallbladder had a curvilinear shape around the gallbladder. No hepatic masses were seen on sonograms, on MR images, or at surgery.

CONCLUSION

Transient focal increased attenuation of the liver may occur on CT scans in patients with acute cholecystitis. The increased attenuation associated with acute cholecystitis has a typical location and pattern. This finding is probably attributable to hepatic arterial hyperemia and to early venous drainage caused by the adjacent inflamed gallbladder. This finding should be differentiated from hypervascular hepatic tumors.

An experimental study of gastric mucosal blood flow in endotoxemia of the rat, with special reference to the vagus nerve and EDRF

Gastric mucosal lesions are an important complication in endotoxemia. In order to define the role played by the vagus nerve and endothelial-derived relaxing factor (EDRF) in gastric mucosal blood flow, an investigation was carried out on four groups of rats: a control group; a group given lipopolysaccharide (LPS, 5 mg/kg); a group given gossypol-acetic acid (gossypol), which has an injurious effect on the vascular endothelial cell; and a group given L-NG-monomethyl arginine (LNMMA). Following the administration of acetylcholine and papaverine hydrochloride (via the splenic artery) and vagus nerve stimulation in all four groups of rats, the effects of vagus nerve stimulation and EDRF on the gastric mucosal blood flow were determined with a laser Doppler rheometer. In the LPS group, the gastric mucosal blood flow was decreased after acetylcholine administration and vagus nerve stimulation. This was also the case in the gossypol group. These findings suggest that inhibition of EDRF release may be responsible for the reduced gastric mucosal blood flow observed in endotoxemia.

Characterization of CD4+ T helper cells in patients with Kawasaki disease (KD): preferential production of tumour necrosis factor-alpha (TNF-alpha) by V beta 2- or V beta 8- CD4+ T helper cells

KD is an acute febrile illness in children characterized by coronary arteritis accompanied by aneurysm and thrombotic occlusion. The etiology of KD is unknown. It has been recently reported that KD is associated with the selective expansion of V beta 2+ and V beta 8.1+ T cells in peripheral blood lymphocytes (PBL), by studying the T cell receptor (TCR) repertoire of in vitro activated T cells. KD may therefore be caused by a superantigen [1-3]. To understand better the immunopathology of KD, we investigated TCR V beta 2 and V beta 8.1 expression on both the T cells of freshly isolated PBL and T cell clones (TCC) from patients with KD. Cytokine production by TCC was also studied. Blood samples were obtained from patients with acute (n = 20) and convalescent (n = 20) KD, age-matched children with non-infectious diseases (n = 18), and healthy adults (n = 20). Among these four groups, there were no significant differences in the percentages of either V beta 2+ or V beta 8.1+ T cells of freshly isolated PBL. The same was true for the CD4+ or CD8+ T cell subsets. One hundred and five TCC (98 CD3+ CD4+ CD8- and seven CD3+ CD4- CD8+) established from the affected skin, lymph node or PBL of six patients with KD were also negative for either V beta 2 or V beta 8.1 TCR. Sixty-eight of 105 TCC (65%) produced detectable levels (> 5 pg/ml) of TNF-alpha (6-1016 pg/ml), in the absence of any stimuli. In contrast, only 11 (10%) of 105 TCC or 7 (7%) of 97 TCC produced detectable levels of IL-2 or IL-6, respectively, in the absence of any stimuli. Stimulation with phytohaemagglutinin (PHA) and phorbol myristate acetate (PMA) induced most TCC to produce higher amounts of TNF-alpha, IL-2 and IL-6. These results suggest that CD4+ T helper cells expressing TCR-beta other than V beta 2 or V beta 8 receptor, primarily through TNF-alpha production, are involved in the immunopathology of KD.

Changes in the mononuclear cell subpopulations of rat cardiac transplant recipients administered FK506 for the treatment of ongoing rejection

The inhibitory effect of ongoing rejection and the changes that occurred in mononuclear cell subpopulations were compared between four groups of rats treated with FK506 or steroids. Group 1 was given no immunosuppressive drugs, group 2 was given FK506 from the day of grafting, group 3 was commenced on FK506 on the 4th day after grafting, and group 4 was commenced on methylprednisolone (MP) on the 4th day after grafting. The graft survival times in groups 2 and 3 were significantly longer than those in groups 1 and 4, and there were fewer CD3+ and CD4+ T lymphocytes in the peripheral blood in the groups treated with immunosuppressive drugs than in group 1. In group 4, the levels in both the peripheral blood and thymus were significantly lower than those in the groups treated with FK506 despite the fact that graft rejection occurred soon after the discontinuation of steroid administration. Moreover, the levels of interleukin-2 receptors and macrophages in groups 2, 3, and 4 were significantly lower than that in group 1 postoperatively; however, the number of macrophages in groups 2 and 3 was significantly lower than that in group 4 on the 10th day after transplantation. The findings of this study demonstrated that FK506, even if administered after rejection has begun, might inhibit the subsequent extensive allograft rejection more specifically and effectively than steroids, and that the measurement of a marker for macrophages in the peripheral blood could be useful for the detection of rejection following allograft transplantation in rats.

[Optimal concentration of contrast medium in helical CT of the thorax]

In 99 examinations of 89 patients, we took CT images of the chest after administering one of three concentrations of contrast medium (iohexol 140 mgI/ml, 240 mgI/ml, 300 mgI/ml) to determine the optimal iodo-concentration for intravenous contrast enhancement in spiral CT. Attenuation values of the superior vena cava, ascending aorta, descending aorta, and pulmonary artery were measured to evaluate the degree of contrast enhancement. Five radiologists judged the image quality by scoring factors such as vascular opacification, delineation of the lung and chest wall, detectability of calcification, lymphadenopathy and pulmonary nodules, and the presence of artifacts. The relationships between the iodo-concentration and the scores were analyzed statistically. The higher the iodo-concentration of the contrast medium administered, the stronger the vascular structures were opacified. There was also a concurrent improvement in the detection of lymphadenopathy. However, artifacts appeared on the administration route as a result of the high-concentration contrast medium, and the image quality was degraded. Among the three groups, iohexol 240 mgI/ml exhibited the best performance, namely, good image quality, so that a high degree of contrast enhancement of the vasculature was obtained with few artifacts due to the contrast medium. However, we believe that iohexol 140 mgI/ml presents no significant problems in routine studies.

Distribution of HLA antigens and haplotypes in the Buryat population of Siberia

Polymorphisms of HLA-A, B, C, DR, and DQ antigens were investigated in a Mongoloid population named Buryat living in Siberia. HLA gene and haplotype frequencies were calculated from the population data obtained from 141 unrelated healthy Buryat adults. Gene frequencies of class I antigens A2, A24, A1, B61, Cw10, and Cw6 were estimated to be more than 10%. For class II, DR4, DR7, DR13, DQ7, and DQ1 antigens were predominant. A phylogenetic tree was constructed based on HLA gene frequencies, and the Buryat population was clustered with the Mongoloid groups in Northeast Asia. In the analysis of HLA-A, C, B, DR, and DQ five-locus haplotype frequencies, seven kinds of haplotypes were calculated to occur at frequencies of more than 2%. Five of the seven common haplotypes have also been described in the other human populations thus far. Some of the haplotypes have been described in European populations, while the others were shared with Northeast Asian Mongoloids as well as Amerindians. Similar situation was also found in the analysis of class I (HLA-A, C, B) three locus haplotypes. These observations suggest the unique genetic background of this Buryat population.