HFE codon 63/282 (H63D/C282Y) dimorphism in German patients with genetic hemochromatosis

Abstract: Genetic hemochromatosis (GH) is closely associated with genes of the major histocompatibility complex (MHC) on chromosome 6. Recently, a candidate gene for GH, with structural similarities to MHC class I genes, designated HLA-H and presently named HFE, has been cloned. The HFE gene is localized telomeric to the MHC and several reports have indicated that the HFE gene is mutated in GH patients. In the present study we have analyzed the relationship of HFE gene variants and disease manifestation in GH patients and family members. Fifty-seven patients with GH, 73 family members and 153 healthy blood donors were studied for the amino acid dimorphism at codon 63 (His63Asp=H63D) and codon 282 (Cys282Tyr= C282Y) of the HFE gene. The codon 63 and 282 dimorphism were defined by PCR amplification of genomic DNA samples and restriction enzyme digestion using RsaI/SnaBI for C282Y and Bcll/Mbo 1 for H63D. Ferritin, transferrin serum levels and total iron-binding capacity were determined prior to therapeutic intervention. The Tyr-282 substitution occurred in 53 (93%) of patients compared with 8 (5.2%) of controls (OR=169, P >0.0001). Fifty-one (90%) patients were Tyr-282 homozygous. In contrast, the Asp-63 substitution was present in 5 (8.8%) of the patients compared with 34 (22%) of controls (OR=0.39, P =NS) with none of the patients being homozygous. In Tyr-282 homozygous GH patients serum ferritin levels, transferrin saturation, liver iron and liver iron index were elevated significantly compared to Tyr-282-negative patients, whereas no difference was observed between Tyr/Cys-282 heterozygous and Tyr-282-negative patients.     

C3d及荷C3d免疫复合物的测定与意义

用抗人Ｃ３和抗人ＩｇＧγ球蛋白组分作固相反应物，建立了检测补体活化片段Ｃ３ｄ及荷Ｃ３ｄ－ＩＣ的ＥＬＩＳＡ法，并对临床各类疾病患者血清Ｃ３ｄ和Ｃ３ｄ－ＩＣ的水平进行了测定，结果表明：慢性肾炎，ＳＬＥ，慢性乙肝及肺炎患者血清Ｃ３ｄ总体水平均较对照组显著增高，分别有５８．５％～７２．２％的病人Ｃ３ｄ含量高于正常上限（Ｐ〈０．０１），且该类病人亦有较高的Ｃ３ｄ－ＩＣ阳性检出率（肺炎患者例外）本项研究中，Ｃ     

Is the effect of acute hyperglycaemia on interdigestive antroduodenal motility and small-bowel transit mediated by insulin?

Acute hyperglycaemia inhibits antroduodenal motility. In non-diabetic subjects this inhibitory effect may result from reactive endogenous hyperinsulinaemia. Therefore, we investigated the effects of hyperinsulinaemia during both hyperglycaemia and euglycaemia on interdigestive antroduodenal motility (perfusion manometry) and duodenocaecal transit time (DCTT; lactulose breath-H₂ test). Six healthy volunteers (age 20–26 years) were studied for 240 min on three separate occasions in random order during: (a) i.v. saline (control); (b) acute hyperglycaemic hyperinsulinaemia (HG) with plasma glucose at 15 mmol L^?1; and (c) euglycaemic hyperinsulinaemia (HI) with plasma insulin at 80 mU L^?1 and glucose at 4–5 mmol L^?1. Results: DCTT was significantly (P < 0.05) prolonged during HG (158 ± 23 min) compared with control (95 ± 25 min), whereas HI had no effect (100 ± 17 min). Mean duration of complete migrating motor complex (MMC) cycles was significantly (P < 0.05) reduced during HG (63 ± 9 min) compared with control (103 ± 15 min) and HI (105 ± 16 min), which resulted from a significantly (P < 0.05) shorter duration of phase II. Antral motility was significantly (P < 0.05) reduced during both HI (20 ± 8 contractions 240 min^?1) and HG (9 ± 5) compared with control (43 ± 7). It is concluded that in healthy subjects hyperglycaemia prolongs DCTT, increases duodenal MMC cycle frequency and inhibits antral motility. Hyperinsulinaemia reduces antral motor activity but has no effect on interdigestive duodenal motility or DCTT. Thus, other factors, apart from insulin, mediate the inhibitory effect of hyperglycaemia on interdigestive intestinal motility and transit.     

Splenic nonenhancement at computed tomography: A sign of the hypoperfusion complex

When splenic nonenhancement is seen at computed tomography, one should look for signs of vascular pedicle injury; if injury to the vascular pedicle is not present, nonenhancement of the spleen could be secondary to severe vasoconstriction and may be considered an additional sign of the hypoperfusion complex. The presence of splenic nonenhancement may also help differentiate the hypoperfusion complex from other types of bowel injury.     

Biochemical analysis of plasma-soluble invariant chains and their complex formation with soluble HLA-DR

The invariant chain (CD74) is preferentially localized in the cytoplasm and regulates the loading of exogenous derived peptides into HLA class II heterodimers. In addition, a small proportion of CD74:class II complexes is also expressed on the cell surface. We identified and quantified soluble CD74 (sCD74) molecules in the plasma and sCD74:sHLA-DR complexes by ELISA. EDTA plasma samples from 86 healthy probands were analyzed. sCD74 could be detected in all samples with a mean concentration of 1.14 relative units±1.04 SD (range 0.17-4.31). Approximately 10% of the samples had increased amounts of sCD74 (3.0 relative units). Complexes of sCD74 and sHLA-DR were detected in all samples and their quantities were positively correlated (r=0.83, p0.001) with the sCD74 concentrations. SDS-PAGE analysis of plasma samples with high sCD74 concentrations (3.0 relative units) revealed four isoforms of sCD74 with molecular weights of 45, 43, 35, 31 kDa corresponding to known sizes of intracellular CD74. However, only molecular weights of the 45 and 43 kDa isoforms of sCD74 are found complexed with sHLA-DR. Our data demonstrate, that CD74 molecules are present in their soluble form in the plasma of healthy probands and form complexes with soluble HLA-DR molecules.     

卡氏肺孢子虫的超微结构观察

采用皮下注射醋酸可的松和低蛋白饲养方法诱发SD大鼠自然感染卡氏肺孢子虫后,取其肺组织,按常规方法进行透射电镜的系统观察。结果除为Yoshida提出的卡氏肺孢子虫生活史的有性增殖和无性增殖循环的最新设想提供了某些形态学依据外,还继Vossen等之后再次发现该病原在1型肺泡上皮细胞内寄生的情况。本文最后就卡氏肺孢子虫对宿主的致病机理进行了讨论。     

Interactions between membrane IgM and the cytoskeleton involve the cytoplasmic domain of the immunoglobulin receptor

Cross-linking induced interactions between the membrane form of immunoglobulin (mIg) and the cytoskeletal matrix have been described by several groups. To date, the function of mIgM association with the cytoskeleton is not yet understood. Delineation of the molecular basis of these interactions will be instrumental in elucidating their function. We have previously shown that the Igα/β heterodimer is not required for ligand-induced mIgM binding to the cytoskeleton. In this study, we have investigated the role of other B cell-specific proteins in mediating these interactions. For this, we expressed mIgM in the non-hematopoietic human cervical carcinoma cell line HeLa S3 and verified the capacity of the surface-expressed IgM to interact with the cytoskeletal matrix upon cross-linking with anti-μ chain antibodies. We show here that only the mIgM molecule itself and no other B cell-specific protein(s) is required in mediating mIgM interactions with actin filaments. In an attempt to determine the cytoskeleton-binding site of mIgM we investigated the role of the cytoplasmic tail of mIgM (KVK) in binding the receptor to actin-based microfilaments. Using mutated forms of mIgM expressed in J558L cells, we show here that KVK plays a role in mediating these interactions. The absence of KVK did not, however, completely abrogate mIgM-cytoskeletal interactions, suggesting that there are additional molecular requirements for the ligand-induced mIgM binding to the cytoskeletal matrix.     

The organization of trigeminotectal and trigeminothalamic neurons in rodents: a double-labeling study with fluorescent dyes

Retrogradely transported fluorescent dyes (fast blue and diamidino-dihydrochloride yellow) were used to compare the distributions of trigeminofugal neurons that project to the superior colliculus and/or the thalamus in three rodent species. The objective was to determine what the projection and collateralization patterns of these trigeminofugal pathways are and whether they are similar among different species. In each anesthetized animal, one dye was injected into the superior colliculus and the other into the topographically congruent area of the thalamus. Counts of the numbers of yellow, blue, and double-labeled neurons were made throughout the trigeminal complex: principalis, pars oralis, pars interpolaris, and pars caudalis. Trigeminothalamic projections were similar in each of the rodent species studied. The densest concentration of retrogradely labeled neurons was in principalis, with substantially fewer neurons in pars interpolaris, and fewer still in pars oralis and pars caudalis. These neurons were generally small and tended to have round or fusiform somata. A common pattern was also noted among the three species for trigeminotectal neurons. Most trigeminotectal projections originated from neurons in pars interpolaris, somewhat fewer from pars oralis, and the fewest from principalis and pars caudalis. These neurons tended to be the largest in each subdivision and were often multipolar. Following paired injections of the tracers, double-labeled neurons were scattered throughout the sensory trigeminal complex and had morphologies characteristic of single-labeled trigeminotectal neurons. Although comparatively few double-labeled neurons were observed in any species, most of those seen were restricted to the ventrolateral portion of pars interpolaris, a position that corresponds to the representation of the vibrissae. These data indicate that, regardless of the rodent species, the vast majority of labeled trigeminal neurons project either to the superior colliculus or the thalamus, but not to both targets. This might be expected on the basis of the very different behavioral roles these structures play. On the other hand, a subpopulation of trigeminal neurons exists (mainly in pars interpolaris) that does project to both the superior colliculus and the thalamus, perhaps because both structures require some of the same somatosensory information to perform their behavioral functions.     

Serum glomerular binding activity is highly correlated with renal disease in MRL/lpr mice.

The pathogenesis of lupus nephritis is felt to be mediated by anti-DNA antibodies. However, the anti-DNA response and renal disease do not entirely correspond. We recently developed a new assay which detects immune elements based on their ability to bind glomeruli as an alternative approach to understanding the pathogenesis of this disorder. The glomerular binding activity (GBA) defined by this assay consists of immune elements containing IgG which interact specifically with renal tissue, the binding of which is DNase-inhibitable, but which do not bind to DNA directly. In the current study we assessed the relationship between GBA and renal disease in MRL/lpr mice (both untreated and cyclophosphamide-treated) and compared it with the anti-DNA assay. Both assays were highly correlated with renal disease in untreated mice in terms of proteinuria. In cyclophosphamide-treated mice, however, only a weak correlation between the anti-DNA assay and proteinuria was apparent. GBA, in contrast, was more strongly correlated with proteinuria in treated mice. This correlation improved substantially when the DNase-sensitive component of the GBA was used. GBA appeared related to, but not covariant with, the anti-DNA response. These results demonstrate that GBA is a better correlate of murine lupus nephritis than the anti-DNA assay, and suggest that the immune elements detected by this assay, the DNase-sensitive component in particular, may be pathogenically important.     

Granulocyte-macrophage colony stimulating factor inhibits class II major histocompatibility complex expression and antigen presentation by microglia

Granulocyte-macrophage colony stimulating factor (GM-CSF) modulates various functions of monocytes/ macrophages including antigen-presenting capacity. Recently it was found that astrocytes produce GM-CSF in the central nervous system (CNS) and that GM-CSF can induce proliferation and morphological changes of microglia. Here we show that GM-CSF can down regulate the interferon-γ-mediated induction of major histocompatibility complex (MHC) class II antigens in microglia, but not in astrocytes. GM-CSF pretreatment completely prevents myelin basic protein-specific T cell proliferation induced by microglia but not astrocytes. GM-CSF did not affect the cell surface expression on microglia of either MHC class I or cell adhesion molecules. The inhibition of microglial MHC class II expression and antigen-presenting function is specific for GM-CSF, as treatment with a different CSF (interleukin-3) did not modulate microglial phenotype or functional capacity. These data suggest that GM-CSF might be involved in the regulation of immune responses within the central nervous system.