0147 Dynamic Alterations in Functional Connectivity Between Sleep- and Wake-Promoting Regions of the Human Brain at the Sleep Onset Period

Introduction

The sleep onset period, involving so-called stage N1 sleep largely, is characterized by a reduction in the amount of alpha activity compared to wakefulness. Various kinds of physiological and psychological changes are also apparent, such as slow eye movements, changes in muscle tonus, and the hypnagogic dream-like mentation. These phenomena are thought to be the reflection of dynamic alterations in the brain during the transition period, however, details of these changes have still been uncovered.

Methods

We aimed to investigate a dynamic shift in the brain connectivity at sleep onset using the method of EEG-fMRI simultaneous recording. Twenty-three healthy subjects participated. EEG/fMRI were recorded simultaneously during an hour’s nap in a 3T-MRI scanner and real-time monitoring of EEG was performed. To record the transition period between multiple times, an experimenter inside a scanner room touched a subject’s foot for inducing arousal when a shift to NREM sleep stage 1 was observed. EEG data were scored according to the AASM criteria. Based on sleep stages defined by polysomnographic findings, we investigated alterations in functional connectivity of sleep- and wake- promoting regions within the hypothalamus and other areas including the thalamus.

Results

Posterior alpha power showed significant positive correlation with BOLD signals in the anterior and medial dorsal thalamus. Connectivity between the thalamus and cortical regions reduced sharply in the descent to sleep stage. Meanwhile, BOLD signals of the sleep- and wake- promoting regions within the hypothalamus fluctuated with certain temporal lags from fluctuations of alpha rhythm at sleep onset.

Conclusion

Present findings provide preliminary evidence of dynamics of wake- and sleep- promoting regions in the human brain in vivo. Our data also support the hypothesis that reduced thalamocortical connectivity which limits the capacity to integrate information is associated with the transition of consciousness at sleep onset.

Support

None

Mid-infrared Photoconductive Response in AlGaN/GaN Step Quantum Wells

AlGaN/GaN quantum structure is an excellent candidate for high speed infrared detectors based on intersubband transitions. However, fabrication of AlGaN/GaN quantum well infrared detectors suffers from polarization-induced internal electric field, which greatly limits the carrier vertical transport. In this article, a step quantum well is proposed to attempt solving this problem, in which a novel spacer barrier layer is used to balance the internal electric field. As a result, a nearly flat band potential profile is obtained in the step barrier layers of the AlGaN/GaN step quantum wells and a bound-to-quasi-continuum (B-to-QC) type intersubband prototype device with detectable photocurrent at atmosphere window (3-5 μm) is achieved in such nitride semiconductors.

Review of polarity determination and control of GaN

Polarity issues affecting III-V nitride semiconductors are reviewed with respect to their determination and control. A set of conditions crucial to the polarity control of GaN is provided for each of the following growth techniques; molecular beam epitaxy (MBE), pulsed laser deposition (PLD) and hydride vapor phase epitaxy (HVPE). Although GaN films might have been deposited by identical growth methods using the same buffer layer technologies, there is often a conflict between the resulting polarities achieved by different research groups. In this paper, we present the implications of the conditions used in each of the processes used for two-step metalorganic chemical vapor deposition (MOCVD), demonstrating systematic control of the polarity of GaN films on sapphire substrates. The potential for confusion in polarity control will be explained, taking into account the implications clarified in our studies. The correlation between the polarity and the growth conditions will be discussed in order to provide a mechanism for the determination and control of the crystal polarity during the growth of GaN films.

Temporal reward discounting and ADHD: task and symptom specific effects

This study investigated a new aspect of the association between ADHD symptoms and delay aversion. Participants were 55 undergraduate Psychology students with varying levels of self-reported ADHD symptoms. Various delay aversion tasks were used, including real and hypothetical temporal discounting tasks previously used in the field of ADHD. ADHD symptoms, specifically hyperactivity/impulsivity, were associated with steep discounting, but only when rewards and delays were real. These data suggest that (1) real temporal discounting tasks are more sensitive to ADHD-related delay aversion than hypothetical ones; (2) delay aversion may be a causal mechanism specifically associated with ADHD-Combined and Hyperactive/Impulsive Types but not Inattentive Type. These findings may help refine behavioral treatment approaches and models of ADHD.

Recurrent miscarriage and variant alleles of mannose binding lectin, tumour necrosis factor and lymphotoxin alpha genes

Variant alleles of the mannose binding lectin (MBL) gene are associated with increased susceptibility to infection and polymorphisms of tumour necrosis factor and lymphotoxin alpha genes (TNF, LTA) are associated with increased severity of infection. Studies have associated recurrent miscarriage with low serum mannose binding lectin concentrations and premature membrane rupture and preterm delivery with elevated maternal and fetal levels of TNF and the TNF (- 308) polymorphism. In this study the frequencies of variant MBL, TNF and LTA alleles in 76 Caucasian couples with idiopathic recurrent miscarriage were compared with those in 69 Caucasian control couples with no history of miscarriage and at least one previous live birth. A new assay based on hybridization to immobilized sequence-specific oligonucleotides (SSO) was used to rapidly detect nine MBL, two TNF and two LTA sequence variants. The assay genotyped all the structural and promoter MBL variants known to influence serum MBL concentrations. This assay was more reliable than restriction digestion or nested allele-specific PCR for the structural variants at codon 54 or 52, respectively. Reliability for codon 57 alleles was not assessed because of the low frequency in this population. The MBL haplotype frequencies in antenatal controls were similar to those reported in other control populations. The frequencies of structural variant MBL genes and of low, medium and high MBL level haplotypes were similar in the recurrent miscarriage and control couples. The TNF and LTA haplotype frequencies were similar in the recurrent miscarriage and control couples. In this carefully defined population no association has been found between recurrent miscarriage and variant alleles of the MBL, TNF or LTA genes.

Endothelial cell-binding activity of anti-U1-ribonucleoprotein antibodies in patients with connective tissue diseases

In order to elucidate the immunological properties of anti-U1-ribonucleoprotein (RNP) antibody, one of the autoantibodies detected in patients with connective tissue diseases (CTDs), we tested the endothelial cell-binding by anti-U1-RNP antibodies and epitopes on human pulmonary artery endothelial cells (HPAECs) to which the autoantibody bound. IgG fractions positive for anti-U1-RNP from patients with CTDs bound to the HPAECs. Furthermore, intact and F(ab')2 IgG anti-U1-RNP purified by affinity chromatography also bound to endothelial cells. The binding activity of IgG fractions positive for anti-U1-RNP to the endothelial cells could be effectively absorbed by U1-RNP-Sepharose. An immunoblotting assay of purified IgG anti-U1-RNP antibodies showed that these antibodies could bind to various membrane proteins of NP40-treated HPAECs such as 68, 48, 43, 38, 33, 29, 28 and 24 kDa. Some bands, 68, 33, 28 and 24 kDa, seemed to correspond to components of U1-RNP, i.e. 68 kDa, A, B' and C peptides, respectively. We confirmed that the anti-U1-RNP antibody from patients with CTDs can directly recognize a variety of antigens on the endothelial surface of the pulmonary artery, including the components of U1-RNP or other unknown polypeptides. These results suggest that binding to pulmonary artery endothelial cells of this autoantibody may be one of the triggers of endothelial cell inflammation in CTDs.

Psychiatric dysfunction in connective tissue diseases: association with Sjögren's syndrome

Abstract We studied 217 patients with connective tissue disease (CTD), comprising 55 patients with primary Sjögren's syndrome (SS), 34 with secondary SS, and 128 without SS. Psychiatric manifestations were investigated using three questionnaires: the Arthritis Impact Measurement Scale 2 (AIMS2), the Cornell Medical Index (CMI), and the Beck Depression Inventory (BDI). Stratified analysis revealed that the frequency of a neurotic state (levels III + IV in CMI) in both primary SS patients (53%; 29% + 24%) and secondary SS patients (67%; 41% + 26%) was significantly greater than in CTD patients without SS (34%; 20% + 14%) (P < 0.05 and P < 0.001, respectively). The median and Q1-Q3 BDI scores in secondary SS patients (7.5 and 4.0-20.0) were significantly higher than those in CTD patients without SS (5.0 and 1.0-10.0) (P < 0.05). Neither the frequency of a neurotic state nor the BDI score differed significantly between patients with primary SS and those with secondary SS. Regression analysis showed significant correlations between the AIMS2 level-of-tension scale and CMI classifications (rs = 0.676, P < 0.001), and between the AIMS2 mood scale and BDI score (rs = 0.679, P < 0.001). SS should always be borne in mind when patients with sicca syndrome and multifarious psychiatric complaints are examined.

Synthesis and antitumor activities of novel 5-deazaflavin-sialic acid conjugate molecules

6-Nitro-5-deazaflavin derivatives bearing O-(methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-alpha- and beta-D-galacto-non-2-ulopyranosylonate)alkyl group (sialosylalkyl group) at N(3) or N(10) and 8-amino-5-deazaflavin substituted with the sialosylalkyl group at the amino group were synthesized and their physicochemical properties as well as antitumor effects on KB and L1210 cells have been investigated. The configurations of the glycosides were determined by 1H NMR and rate of hydrolysis of the glycosidic bond. It has been found that these conjugate molecules show significant antitumor activities. Combination of an 8-amino-5-deazaflavin with the sialosylalkyl group have been found to give rise to significant increase in antitumor activities of the compound. Antitumor effects of 6-nitro-5-deazaflavin-sialic acid conjugate molecules were similar or rather weak in comparison with those of the 6-nitro-5-deazaflavin derivatives without sialosylalkyl group.

Immunological analysis of pulmonary hypertension in connective tissue diseases

OBJECTIVE

To analyze the immunological characteristics of the sera of patients with inflammatory connective tissue diseases complicated by pulmonary hypertension (PH).

METHODS

Sera of 24 patients with mixed connective tissue disease complicated by PH (MCTD-PH), sera of 11 patients with other connective tissue diseases complicated by PH (Other-PH; 6 systemic sclerosis, 3 systemic lupus erythematosus, 2 rheumatoid arthritis), and sera of 15 patients with MCTD not complicated by PH (MCTD-non-PH) were tested for IgG antibodies against U1RNP proteins, U1RNP-70K protein, U1RNP-A protein, and U1RNP-C protein, and for IgG and IgM antibodies to beta2-glycoprotein I dependent cardiolipin (CL) and human umbilical vein endothelial cells. We also measured the serum levels of von Willebrand factor related antigens and interleukin 6 (IL-6).

RESULTS

(1) The titers of the anti-U1RNP, anti-U1RNP-70K, anti-U1RNP-A, and anti-U1RNP-C antibodies were significantly higher in the MCTD-PH and MCTD-non-PH groups than in the Other-PH group. However, there were no statistically significant differences in the titers of these 4 antibodies between the MCTD-PH and MCTD-non-PH groups. (2) The titers of the IgG aCL and the serum IL-6 levels were significantly higher in the MCTD-PH group than in the MCTD-non-PH group. (3) Statistically significant correlations between the anti-U1RNP and IgG anti-CL antibody titers, and between the IgG anti-endothelial cell and IgG anti-CL antibody titers were observed within the MCTD-PH and Other-PH groups, but not within the MCTD-non-PH group.

CONCLUSION

The occurrence of anti-U1RNP, anti-endothelial cell, and anti-CL antibodies is associated with PH in certain patients with connective tissue disease.

Increase of cytokine production by pulmonary artery endothelial cells induced by supernatants from monocytes stimulated with autoantibodies against U1-ribonucleoprotein

OBJECTIVE

To clarify the pathogenetic role of autoantibodies against U1-RNP (ribonucleoprotein) (anti-U1-RNP) in mixed connective tissue disease (MCTD), we examined whether supernatants of monocytes which were stimulated with anti-U1-RNP could induce the production of proinflammatory cytokines by human pulmonary artery endothelial cells (HPAECs).

METHODS

Monocytes from MCTD patients (n = 11) and normal volunteers (n = 11) were stimulated with purified antibodies against U1-RNP or double-stranded DNA and their supernatants were added to cultures of HPAECs. Cell-associated cytokines were assayed by an enzyme-linked immunosorbent assay.

RESULTS

The supernatants of anti-U1-RNP-stimulated MCTD monocytes significantly up-regulated the cell-associated production of IL-1 alpha (p < 0.01) and IL-6 (p < 0.01) by HPAECs compared with their production by normal IgG-stimulated MCTD monocytes, whereas the cell-associated production of IL-1 beta and TNF-alpha by HPAECs was not up-regulated. The supernatants of anti-U1-RNP-stimulated monocytes from normal volunteers similarly up-regulated the cell-associated production by HPAECs of IL-1 alpha (p < 0.01) and IL-6 (p < 0.01), but not of IL-1 beta and TNF-alpha. Supernatants of monocytes stimulated with the F(ab')2 preparation of anti-U1-RNP antibodies enhanced the amounts of both Il-1 alpha and IL-6 associated with HPAECs almost as effectively as those stimulated with intact autoantibody molecules. Inhibition experiments employing specific anti-cytokine antibodies of anti-U1-RNP-stimulated monocyte supernatants suggested that soluble factors, including cytokines, in monocyte supernatants could enhance the cytokine association with HPAECs.

CONCLUSION

Up-regulation by anti-U1-RNP autoantibodies of proinflammatory cytokines associated with vascular endothelial cells may play a role in the immunopathological processes leading to proliferative vasculopathy, a characteristic of MCTD.

Up-regulation of intercellular adhesion molecule-1 (ICAM-1), endothelial leucocyte adhesion molecule-1 (ELAM-1) and class II MHC molecules on pulmonary artery endothelial cells by antibodies against U1-ribonucleoprotein

In order to elucidate the pathogenic role(s) of autoantibodies in connective tissue disease (CTD), we examined whether autoantibodies against U1-ribonucleoprotein (RNP) and double-stranded (ds) DNA can up-regulate ICAM-1, ELAM-1 and class I and II MHC molecule expression on pulmonary artery endothelial cells (HPAEC). ICAM-1, ELAM-1 and class II MHC molecule expression on HPAEC cultured in the presence of anti-U1-RNP-containing and anti-dsDNA-containing IgG from CTD patients was up-regulated significantly in comparison with that on HPAEC cultured with IgG from normal healthy volunteers. Affinity chromatographic enrichment and depletion of the anti-U1-RNP antibody content of anti-U1-RNP-containing IgG confirmed that the anti-U1-RNP antibody did up-regulate ICAM-1, ELAM-1 and class II MHC molecule expression. The finding that an IgG F(ab')2-purified anti-U1-RNP antibody also up-regulated expression of these molecules may indicate that mechanisms other than Fc receptor-mediated stimulation are involved. These in vitro findings suggest that autoantibodies against U1-RNP and dsDNA play important roles in the immunopathological processes leading to the proliferative pulmonary arterial vasculopathy observed in CTD patients with pulmonary hypertension by up-regulating adhesion and class II MHC molecule expression on endothelial cells.

Association of variants of the gene for mannose-binding lectin with susceptibility to meningococcal disease. Meningococcal Research Group

BACKGROUND

The reasons why meningococcal disease develops in only a small proportion of individuals carrying the causative bacteria are unknown. Differences in host responses to bacterial colonisation are thought to be involved, since people with deficiencies in the terminal components of the complement pathway, or of properdin, are susceptible to meningococcal disease. We postulate that genetic variants of mannose-binding lectin (MBL), a plasma opsonin that initiates another pathway of complement activation, might similarly cause susceptibility to meningococcal disease.

METHODS

The frequency of variants of the MBL gene was ascertained in children with meningococcal disease and controls from two independent studies; one hospital-based (194 patients and 272 controls [patients with non-infectious disorders]), and one community-based (72 patients and 110 controls [healthy individuals]), by means of PCR and restriction-enzyme digestion, with confirmation by DNA sequencing.

FINDINGS

The proportion of people homozygous for MBL-variant alleles was higher in patients with meningococcal disease than in controls in the hospital study (15 [7.7%] vs four [1.5%]; odds ratio 6.5 [95% CI 2.0-27.2]) and in the community study (six [8.3%] vs three [2.7%]; 4.5 [0.9-29.1]). The population attributable fraction of cases attributable to MBL variants (homozygous and heterozygous) was 32%.

INTERPRETATION

The MBL pathway is a critical determinant of meningococcal-disease susceptibility, and genetic variants of MBL might account for a third of all disease cases.

Mannose-binding protein in HIV-seropositive patients does not contribute to disease progression or bacterial infections

This study set out to investigate whether plasma mannose-binding protein (MBP) deficiency caused by mutations in the MBP gene associates with pyogenic or opportunistic infections in HIV-infected patients. Plasma samples were selected randomly from 131 HIV-infected patients followed prospectively for a period not exceeding 12 months or until death. Plasma MBP concentrations were measured by an ELISA and genotyping was determined by amplification of exon 1 of the MBP gene by polymerase chain reaction (PCR) technology, followed by restriction enzyme analysis and Southern blotting using sequence-specific oligonucleotide probes. Neither MBP concentration nor genotype was found to associate with disease progression or opportunistic infection rate. There was an unexpected increased bacterial infection rate in patients with MBP levels greater than 100 ng/ml and wild type genotype. Thus, MBP does not appear to play a role in HIV infection. MBP is an acute phase reactant and this may explain the higher levels in those with more frequent pyogenic infections.

Increased levels of matrix metalloproteinase-3 in sera from patients with active lupus nephritis

OBJECTIVE

To determine the matrix metalloproteinase-3 (MMP-3) levels in sera from patients with systemic lupus erythematosus (SLE) and to analyse the relationships between MMP-3 and clinical and laboratory features.

METHODS

Serum MMP-3 levels were measured by an enzyme immunoassay in 124 patients with SLE and 237 patients with other systemic rheumatic diseases.

RESULTS

The frequencies of patients with high MMP-3 levels were 76% in SLE and 82% in rheumatoid arthritis (RA). The level of MMP-3 in the SLE patients was 193.0 +/- 171.5 ng/ml (mean +/- SD) and was almost equal to the level in the RA patients (259.5 +/- 255.6 ng/ml). The MMP-3 levels were significantly higher in SLE patients who had a history of the following abnormalities: persistent proteinuria, cellular casts, anti-double stranded DNA antibodies, decreased C3, decreased creatinine clearance (p < 0.001), circulating immune complex (p < 0.01), malar rash, hypoalbuminemia, or decreased C4 (p < 0.05). The serum MMP-3 level in patients with SLE at admission showed direct correlations with serum uric acid, total cholesterol (p < 0.001), triglyceride, the white blood cell count, and the neutrophil count (p < 0.05), as well as inverse correlations with the total protein (p < 0.01), and IgG (p < 0.05). In SLE patients with active renal disease, the median MMP-3 level at admission and that at 6 months after admission were significantly higher than that at 6 months before admission.

CONCLUSIONS

The increased level of serum MMP-3 in SLE is closely associated with clinical features relevant to lupus nephritis, suggesting that it plays a role in the pathogenesis of this condition.

Progressive multifocal leukoencephalopathy resembling central nervous system systemic lupus erythematosus

A 21-year-old woman with a 6-year history of SLE presented with a speech disturbance and right hand clumsiness along with manifestations of active disease suggesting central nervous system SLE. Despite aggressive treatment for SLE, her neurological condition worsened. MRI demonstrated low intensity in T1-weighted images and high intensity in T2-weighted images in the white matter of the bilateral cerebrum and cerebellum, compatible with progressive multifocal leukoencephalopathy (PML). Intraspinal administration of interferon-beta seemed to slow the deterioration of her MRI and neurological findings. However, she eventually developed decerebrate rigidity and died due to candidemia. DNA of the JC virus was detected in the autopsied brain by the polymerase chain reaction technique. PML should always be borne in mind when examining patients with SLE showing neurological abnormalities.

Mannose binding protein deficiency is not associated with malaria, hepatitis B carriage nor tuberculosis in Africans

We retrospectively studied MBP genotypes in patients with malaria, tuberculosis (TB), and persistent hepatitis B virus (HBV) carriage, in clinics and hospitals in The Gambia. Children under 10 years with cerebral malaria and/or severe malarial anaemia, were compared with children with symptomatic, mild malaria, and controls of the same age and ethnicity. Adult TB cases with smear-positive pulmonary TB were compared with healthy blood donors from the same ethnic groups. Malaria cases and controls were tested for hepatitis B core antibody (anti-HBc) and surface antigen (HBsAg). TB patients were tested for HIV antibodies. Genotyping used sequence-specific oligonucleotide analysis to identify MBP variant alleles. Overall, 46% (944/2041) of patients and controls were homozygous for the wild-type MBP allele, 45% (922/2041) were carriers of a single variant allele and 8.6% (175/2041) had two variant alleles. Neither homozygotes nor heterozygotes for MBP variants were at increased risk of clinical malaria, persistent HBV carriage or TB. The most common mutation in Africans, the codon 57 variant allele, was weakly associated with resistance to TB (221/794 in TB cases and 276/844 in controls, p = 0.037). MBP deficiency is not a significant risk factor for persistent HBV, severe malaria nor pulmonary TB in West Africa.

The role of collectins in host defense

Mannose-binding protein (MBP) belongs to a group of Ca(2+)-dependent lectins called collectins that play a role in first-line host defense. It recognizes specific carbohydrate residues (mannose and N-acetylglucosamine) on the surface of microorganisms and promotes the killing of microbes either by acting directly as an opsonin or by activating the lectin complement pathway. The collagenlike domain of MBP is important for the binding of MBP to the collectin receptors expressed on different phagocytes, and for activation of complement. The binding of MBP to bacteria, viruses, and parasites has been demonstrated in vitro. Three major mutations have been found in exon 1 of the MBP gene, which encodes the collagenous domain of the protein. These mutations cause low levels of serum MBP and have been linked with lifelong risk of infection. The homozygotes for these mutations are especially susceptible to severe infections.

Histological evaluation of destructive monoarthropathy in mixed connective tissue disease

The synovium from a patient with mixed connective tissue disease and destructive ankle monoarthritis was studied in detail to determine its immunohistological characteristics. Fibrinoid necrotic tissue on the surface of the synovium, multi-layered lining cells, increased numbers of capillaries, interstitial edema, infiltration of macrophages, relatively small numbers of lympho-plasma cells and polymorphonuclear leukocytes, scattered bone fragments, and multinucleated giant cells were observed. Many cells in the lining and sublining area were positive for CD68 and MAC387. Lower layers of increased lining cells which had a spindle shape were positively stained with anti-HLA-DR antibody. The small arteries in the deeper part of the synovium revealed obstruction or highly stenotic change. These findings suggest that obstructive circulatory disturbance due to endothelial injury might influence the progression of arthritis.

[Antinuclear antibody screening by an enzyme-linked immunosorbent assay using multiple nuclear antigens]

We assessed the clinical value of an enzyme-linked immunosorbent assay (ELISA) kit (MESACUP ANA, MANA) which uses multiple nuclear antigens for screening antinuclear antibody (ANA). Since the screening procedure for ANA by the indirect fluorescence method (FANA) requires trained personnel and gives rather subjective results, development of a suitable screening test for ANA by ELISA which uses specific nuclear antigens has been long awaited. Serum samples from 350 patients with connective tissue diseases (CTD), and from 300 normal subjects were assayed for ANA by ELISA and the results were compared with those of FANA and of single-antigen ELISAs for RNP, Sm, SS-A, SS-B, Scl-70, Jo-1, dsDNA, and ssDNA. For discrimination between patients with systemic lupus erythematosus and normal subjects, the sensitivity, specificity and accuracy for MANA were 85.7%, 97.5%, and 91.6%, and those for FANA were 95.8%, 77.0%, and 86.4%, respectively. Analysis of CTD sera showing discordant results between FANA and MANA using single-antigen ELISAs revealed that FANA - MANA + sera (n = 8) contained antibodies against SS-A (n = 1) or dsDNA (n = 3) or ssDNA (n = 3), and that some FANA + MANA - sera (n = 82), which were frequently found in RA patients (43/98, 43.9%), also contained antibodies against RNP (n = 3) or ssDNA (n = 13). MANA + normal sera (n = 9) were found to contain antibodies against SS-A (n = 1) or dsDNA (n = 1) or ssDNA (n = 2). In conclusion, MANA was found to be objective, much less labor intensive and suitable for screening large numbers of CTD sera for disease-specific ANAs.

Association of mutations in mannose binding protein gene with childhood infection in consecutive hospital series

OBJECTIVE

To determine the extent to which mutations in the mannose binding protein gene predispose to childhood infection.

DESIGN

Clinical details and genotype of mannose binding protein determined in consecutive children attending a paediatric department.

SETTING

Inner city hospital paediatric service in London.

SUBJECTS

617 children attending hospital between October 1993 and August 1995.

MAIN OUTCOME MEASURE

Infection as the cause for attendance or admission in relation to mutations in the mannose binding protein gene.

RESULTS

The prevalence of mutations in the mannose binding protein gene in children with infection (146/345) was about twice that in children without infection (64/272) (P < 0.0001). Increased susceptibility to infection was found in both heterozygotic and homozygotic children. 13 out of 17 children homozygotic for variant alleles presented with strikingly severe infections, including 6 with septicaemia.

CONCLUSIONS

The findings suggest that mutations in the mannose binding protein gene are an important risk factor for infections in children. Screening for such mutations should be included in the investigation of severe or frequent infections.

Mutation of gene of mannose-binding protein associated with chronic hepatitis B viral infection

BACKGROUND

Persistent with hepatitis B virus (HBV) affects 350 million people worldwide, and 20-40% of infected patients die of cirrhosis and liver cancer. Little is known about the host factors that determine the variable natural history. Studies have focused on the role of acquired rather than innate immunity. We have investigated the prevalence of mutations in the gene for mannose-binding protein (MBP), which have been associated with susceptibility to bacterial and fungal infections.

METHODS

Mutations in the MBP gene were sought by sequence-specific oligonucleotide hybridisation, site-directed sequencing in Caucasian and Asian patients with HBV infection, and in HBsAg-negative controls.

FINDINGS

A mutation in codon 52 of the MBP gene was present in two (11%) of 19 Caucasian patients with acute hepatitis B and nine (27%) of 33 Caucasian patients with chronic hepatitis B, compared with four (4%) of 98 Caucasian controls (p = 0.0004). By contrast the prevalence of the mutation was similar in Asian patients with chronic hepatitis B and in Asian controls (one [5%] of 20 vs two [2%] of 117). Mutations in codon 54 and codon 57 were found in similar proportions of patients and controls.

INTERPRETATION

These findings show in Caucasian, but not Asian, patients an association of the codon 52 mutation of the MBP gene with persistent HBV infection. They suggest an important role for this gene, or a gene in linkage disequilibrium with MBP, in determining outcome after HBV infection in adult but not neonatal life.

Deposition velocity of gaseous organic iodine from the atmosphere to rice plants

To obtain parameter values for the assessment of 129I transfer from the atmosphere to rice, deposition of CH3I to rice plants has been studied. The mass normalized deposition velocity (VD) of CH3I for rough (unhulled) rice was 0.00048 cm3 g-1 s-1, which is about 1/300 of that of I2. Translocation of iodine, deposited as CH3I on leaves and stems, to rice grain was negligibly small. Distribution of iodine between hull and inner part of the grain was found to depend also on the chemical forms of atmospheric iodine to be deposited. The ratio of the iodine distribution in a grain exposed to CH3I was as follows: rough rice:brown rice (hulled rice):polished rice = 1.0:0.49:0.38. The distribution ratio in polished grains for CH3I exposed rice was about 20 times higher than that for I2.

Clinical significance of the serum lipoprotein(a) level in patients with systemic lupus erythematosus: its elevation during disease flare

OBJECTIVE

To determine the clinical significance of serum lipoprotein(a) [Lp(a)] levels in patients with systemic lupus erythematosus (SLE).

METHODS

Serum Lp(a) levels in 77 patients with SLE were measured by turbidimetric immunoassay.

RESULTS

The median serum Lp(a) levels in all the SLE patients (14.4 mg/dl) and in those with active disease (Group A; 19.6 mg/dl, n = 39) at admission were significantly higher than those in healthy subjects (11.9 mg/dl, p < 0.05 and p < 0.001, respectively). The serum Lp(a) levels in SLE patients correlated directly with the serum cholesterol (p < 0.001) and urinary protein (p < 0.001) levels and inversely with the serum albumin levels (p < 0.02). Analysis limited to Group A patients with renal disease (Group A + RD, n = 28) revealed that the median serum Lp(a) level at the time of admission (OM) was significantly higher than those at 6 months before (-6M, p < 0.01) and at 6 months after admission (+6M, p < 0.01). Moreover, the serum Lp(a) level decrease from 0M to +6M in Group A+RD correlated significantly with the serum albumin level increase (p < 0.05). Multiple regression analysis demonstrated that the serum albumin level increment, the SLEDAI score decrement, the cholesterol level at 0M and the total dose of oral corticosteroids administered during the 0M to +6M period contributed independently and significantly to the serum Lp(a) level decrement from 0M to +6M in Group A + RD.

CONCLUSION

Our study is the first to reveal that hypoalbuminemia appearing during disease flare plays an important role in increasing the serum Lp(a) levels in lupus patients with renal disease and shows that corticosteroid treatment reduced the elevated serum Lp(a) levels almost to original levels.

Clinical features of patients with juvenile onset mixed connective tissue disease: analysis of data collected in a nationwide collaborative study in Japan

OBJECTIVE

To analyze the clinical features and outcome of juvenile-onset mixed connective tissue disease (MCTD).

METHODS

Clinical and laboratory findings were compared in 2 groups of MCTD patients divided according to age at onset: juvenile onset: under 16 yrs: adult onset: 16 yrs or older).

RESULTS

Systemic lupus erythematosus-like symptoms, such as facial erythema, photosensitivity. LE cells, lymphadenopathy, and cellular casts, were more frequent in juvenile onset MCTD than in the adult form of the disease. On the other hand, scleroderma-like symptoms, such as esophageal hypomotility, scleroderma-like lesions evident on skin biopsy, pulmonary involvement, proximal scleroderma, and pitting scars, were less frequent in juvenile onset MCTD than in the adult form. Patients with juvenile onset MCTD more frequently met the classification criteria for systemic lupus erythematosus (SLE) and less frequently met those for progressive systemic sclerosis (SSc), compared to patients with adult onset MCTD. At disease onset, hand edema and stiffness were observed less frequently in juvenile onset MCTD than in the adult form. Furthermore, the mortality rate was lower in the former than in the latter (2.8% vs 8.4%).

CONCLUSION

Although previous studies have reported severe symptoms and adverse outcome for juvenile onset MCTD, we conclude from this nationwide study in Japan that patients with juvenile onset MCTD exhibit more SLE-like and fewer SSc-like features and have a relatively favorable outcome.

Diffuse interstitial pulmonary amyloidosis in rheumatoid arthritis

We describe a woman with seronegative rheumatoid arthritis (RA) who presented with diffuse septal pulmonary amyloidosis mimicking interstitial rheumatoid lung disease. Her systemic amyloidosis was diagnosed by biopsy of the kidney, stomach mucosa, and salivary glands 28 years after the onset of RA. Diffuse interstitial pulmonary infiltrates had been noted since that diagnosis, but infiltrates had been considered due to rheumatoid lung. Results of pulmonary function tests, which revealed restrictive changes and decreased diffusion capacity, were also compatible with rheumatoid lung disease. Pulmonary amyloidosis was diagnosed at autopsy. Pulmonary amyloidosis should be considered a cause of pulmonary infiltrates in patients with longstanding RA.

Mutations in the human mannose-binding protein gene: frequencies in several population groups

Mannose-binding protein (MBP; mannan-binding protein, mannan-binding lectin) is a member of the collectin family of proteins and is thought to be important in innate immunity. We have previously shown high frequencies of two distinct mutations in codon 54 and codon 57 of exon 1 of the MBP gene in non-African and African populations, respectively. These result in low levels of the protein and an opsonic deficiency but the frequencies also suggest some selective advantage for low MBP levels. A third mutation in codon 52 occurs at a much lower frequency. We have now extended our earlier studies to other populations. In the south-west Pacific (Papua New Guinea and Vanuatu) neither the codon 52 nor the codon 57 mutation was detected and the codon 54 mutation was significantly less common (gene frequencies of 0.07 and 0.01, respectively) than in other non-African populations (gene frequencies 0.11-0.16). This could be explained by relatively recent admixture. The ancestral Melanesian population probably diverged some 50,000-60,000 years ago and our data suggest that the codon 54 mutation may have occurred after that even but before the divergence of European-Asian groups (40,000 years ago). Two further sub-Saharan populations were also studied: a group of Xhosa from South Africa were similar to Gambians, with a high gene frequency for the codon 57 mutation (0.27) and no evidence of the codon 52 or 54 mutations. In contrast, San Bushmen from Namibia had low frequencies of both the codon 57 mutation (0.07) and the codon 54 mutation (0.03). Again the codon 52 mutation was not found. This pattern is unique amongst sub-Saharan populations studied to date and suggests that this population may have been subjected to different selective pressures.

Distinct physicochemical characteristics of human mannose binding protein expressed by individuals of differing genotype

Mannose binding protein (MBP) is a serum collectin (collagenous lectin) believed to be of importance in innate immunity. Three point mutations, in codons 52, 54 and 57 of exon 1 of the human MBP gene, have been predicted to affect the tertiary structure of the collagenous region of the protein, and are known to be associated with low serum concentrations of MBP. However, other groups working with recombinant mutant proteins have claimed that the proteins are expressed and assembled normally. The aim of the present investigation was to characterize the effects of these mutations on the physicochemical nature of MBP that is present in the circulation in vivo, and for this we used polyacrylamide gel electrophoresis, gel filtration and sucrose density gradient centrifugation, followed by immunoblotting and enhanced chemiluminescence. The circulating wild-type MBP appeared to comprise a mixture of polymers formed from two to eight subunits (each based on three identical 32,000 MW polypeptide chains) of apparent molecular weights 200,000-700,000, with dimers and trimers constituting the predominant forms. Individuals homozygous for the codon 54 or 57 mutation had dramatically reduced concentrations of serum MBP, mainly comprising material of an apparent molecular weight of 120,000-130,000. Heterozygous individuals showed characteristics of both phenotypes. In contrast to the results obtained with artificial expression systems, our data suggest that individuals homozygous for the MBP mutations have very little circulating protein and that this comprises mainly low molecular weight material.

Mannose binding protein gene mutations associated with unusual and severe infections in adults

A defect in opsonisation can cause a common immunodeficiency. A mutation in mannose binding protein (MBP) caused by point mutations in the MBP gene will lead to such a defect. This type of syndrome can cause recurrent infections in infants between 6 and 18 months of age but is not generally believed to predispose to adult infections. We looked at 4 patients with severe and unusual infections in whom MBP gene mutations were the only identified cause of immunodeficiency and one patient with combined MBP and IgA deficiency. We analysed the MBP genotypes of all the patients in whom we suspected an immunodeficiency because of their clinical history. Infections seen were recurrent skin abscesses, chronic cryptosporidial diarrhoea, meningococcal meningitis with recurrent herpes simplex, and fatal klebsiella lobar pneumonia. Both sexes were affected and ages ranged from 15 to 56 years. Two patients were homozygous for codon 54 mutations, one patient had codon 52 and codon 54 mutations and was phenotypically homozygous, and two patients were heterozygous for codon 54 mutations. Individuals homozygous for MBP mutations are unusual in the general population (approximate frequency 0.3%). The occurrence of three homozygotes for MBP mutations among these five infected patients suggests that MBP deficiency may confer a life-long risk of infection.

Enhanced synthesis of cytokines by peripheral blood monocytes cultured in the presence of autoantibodies against U1-ribonucleoprotein and/or negatively charged molecules: implication in the pathogenesis of pulmonary hypertension in mixed connective tissue disease (MCTD)

An attempt was made to determine whether addition of purified autoantibodies against U1-ribonucleoprotein (RNP) and negatively charged molecules (cardiolipin and double-stranded (ds) DNA) to cultures of peripheral blood monocytes could enhance the synthesis of cytokines in patients with MCTD and normal healthy volunteers. It was found that: (i) at the baseline, levels of cytokines such as IL-1 alpha, IL-1 beta and IL-6 extracellularly released by or associated with monocytes were significantly higher in MCTD patients than in normal subjects; (ii) addition of antibodies against U1-RNP to cultures of MCTD monocytes resulted in a significant overall increase of the released and cell-associated IL-1 alpha, IL-1 beta and IL-6. On the other hand, addition of antibodies against cardiolipin or dsDNA to cultures of MCTD monocytes resulted in a significant increase of released and/or cell-associated IL-1 alpha and IL-1 beta; (iii) addition of these autoantibodies to cultures of normal monocytes resulted in a significant overall increase of released and cell-associated IL-1 alpha, IL-1 beta and IL-6. The extent of enhancement of cytokines released by or associated with monocytes was greater in normal subjects than in MCTD patients; (iv) a F(ab')2 preparation of autoantibodies against U1-RNP also enhanced the level of released and cell-associated IL-1 alpha. Our findings that both autoantibodies against U1-RNP and negatively charged molecules were able to enhance the synthesis of cytokines by monocytes suggest that these autoantibodies might cause derangement of endothelial cells and lead to proliferative vasculopathy, which is a characteristic of pulmonary hypertension in MCTD.

Antiendothelial cell antibodies and their relation to pulmonary hypertension in systemic lupus erythematosus

OBJECTIVE

Antiendothelial cell antibodies (aECA) have been demonstrated in patients with systemic lupus erythematosus (SLE), but their role in the pathogenesis of this disease remains unclear. We investigated the association of aECA and anticardiolipin antibodies (aCL) with clinical and laboratory findings in patients with active SLE.

METHODS

Sera from 28 patients with active SLE and 22 healthy controls were assayed for IgG and IgM-aECA by cellular ELISA method using cultured human umbilical vein endothelial cells and IgG-aCL by ELISA method.

RESULTS

Serum titers of both IgG and IgM-aECA were significantly higher in active SLE than in healthy controls. Titers of IgG-aECA were unrelated to titers of IgG-aCL. Patients with pulmonary hypertension demonstrated a marked elevation of serum titer of both IgG and IgM-aECA compared with patients without pulmonary hypertension. In addition, patients with digital vasculitis showed a significant elevation of serum titer of both IgG and IgM-aECA compared with patients without digital vasculitis. Serum titers of IgG-aECA in patients with Raynaud's phenomenon and of IgM-aECA in patients with serositis were each significantly increased compared with patients without such findings.

CONCLUSION

aECA were unrelated to aCL. Serum titers of aECA are elevated in patients with active SLE, especially with pulmonary hypertension, digital vasculitis, Raynaud's phenomenon or serositis. Since pulmonary hypertension in SLE has been associated with digital vasculitis, Raynaud's phenomenon and serositis, aECA may be involved in the pathogenesis of vascular injury, leading to these manifestations.

Phylogenetic comparison between archetypal and disease-associated JC virus isolates in Japan

We examined the phylogenetical correlation between two types of JC virus (JCV) isolates, archetypes derived from the urine of nonimmunocompromised individuals and PML-types derived from the brain of patients with progressive multifocal leukoencephalopathy (PML) in Japan. A phylogenetic tree was constructed for eight JCV isolates, five PML-types obtained in this and previous studies and three representative archetypes, from DNA sequence data on the VP1 (major capsid protein) gene. The eight isolates were divided into two major groups, named subtypes MY and CY after the representative archetypal isolates. Four of five PML-type isolates belonged to subtype MY, and the other one to subtype CY. Isolates belonging to subtype MY were further divided into two groups; one group containing archetype MY and three PML-types and the other one containing archetype YI and a PML-type. These findings, together with those in our previous study that correlated various JCV isolates in the world provide evidence for the hypothesis that JCVs associated with PML may have been generated from archetypal JCVs persisting in the patients.