Analysis of CARD15/NOD2 haplotypes fails to identify common variants associated with rheumatoid arthritis susceptibility

OBJECTIVES

The CARD15/NOD2 gene product plays an important role in host response to bacterial lipopolysaccharides and bacterial muramyl dipeptide via activation of NF-kappaB in monocytes. Mutations in CARD15 are associated with Crohn's disease (CD), a chronic inflammatory bowel disease. In this study we sought to determine whether CD-associated mutations or any common variants of this gene might contribute to susceptibility to another chronic inflammatory disease, rheumatoid arthritis (RA).

METHODS

We genotyped 376 Caucasian RA cases and 376 ethnically matched healthy controls for three CD-associated CARD15 mutations. We also genotyped these 752 individuals for 12 common CARD15 single nucleotide polymorphisms (SNPs), determined the linkage disequilibrium structure of the gene, and compared the frequencies of the common CARD15 haplotypes in the RA cases and controls.

RESULTS

None of the CD-associated mutations or the CARD15 SNPs was associated with susceptibility to RA. We also found no significant difference in the frequencies of any of the common haplotypes of the CARD15 gene in RA patients and controls. Our haplotype analysis was consistent with earlier observations that all three CD-associated variants independently arose on the same ancestral haplotype.

CONCLUSIONS

These data suggest that CARD15 variants are not associated with RA susceptibility.

Urinary Tract Infections During Pregnancy

OBJECTIVE

To provide a comprehensive review of urinary tract infections (UTIs) during pregnancy. All aspects of UTIs, including epidemiology, pathogenesis, resistance, clinical features, diagnosis, treatment, and prevention, were reviewed.

DATA SOURCES

MEDLINE (1966–August 2003) and Cochrane Library searches were performed using the key search terms urinary tract infection, pyelonephritis, cystitis, asymptomatic bacteriuria, and resistance.

STUDY SELECTION AND DATA EXTRACTION

All article abstracts were evaluated for relevance. Only articles pertaining to pregnancy were included. The majority of published literature were review articles; the number of original clinical studies was limited.

DATA SYNTHESIS

UTIs are the most common bacterial infections during pregnancy. They are characterized by the presence of significant bacteria anywhere along the urinary tract. Pyelonephritis is the most common severe bacterial infection that can lead to perinatal and maternal complications including premature delivery, infants with low birth weight, fetal mortality, preeclampsia, pregnancy-induced hypertension, anemia, thrombocytopenia, and transient renal insufficiency. Enterobacteriaceae account for 90% of UTIs. The common antibiotics used are nitrofurantoin, cefazolin, cephalexin, ceftriaxone, and gentamicin.

CONCLUSIONS

Therapeutic management of UTIs in pregnancy requires proper diagnostic workup and thorough understanding of antimicrobial agents to optimize maternal outcome, ensure safety to the fetus, and prevent complications that lead to significant morbidity and mortality in both the fetus and the mother.

Production of matrix metalloproteinase 2 in fibroblast reaction to mechanical stress in a collagen gel

The reaction of fibroblasts to mechanical forces generated by fibroblasts themselves in anchored collagen lattices was studied. Fibroblasts were cast in collagen gels. Free retracted gels (RG) were compared with stressed gels (SG) in 3-day and 14-day experiments. As previously described, SG showed an increase in protein, mainly collagen, biosynthesis. Matrix metalloproteinases (pro-MMP-2 and MMP-2) were studied by zymography. Certain cell membrane components, integrin alpha(2) and phosphatidylserine, were studied by flow cytometry with antibodies against the integrin alpha(2) subunit and with annexin V binding. Mechanical stress stimulated production of pro-MMP-2 both in the short-term (3-day) and the longer term (14-day) cultures. However, the pro-enzyme was not more activated and there was no difference in the amount of MMP-2 between RG and SG. There was only an increase with time under both conditions. The stressed fibroblasts reacted early with an increase in the integrin alpha(2) subunit, but the stimulated cells disappeared from the 14-day cultures. The number of cells measured in terms of the amount of DNA decreased between day 3 and day 14, mainly in the SG due to cytolysis. This cell stress was related to an alteration in the plasma membrane detected by the annexin V marker.

[The clinical value of the TSGF pre and post-therapy in patients with nasopharyngeal carcinoma(NPC)]

OBJECTIVE

To investigate the role of TSGF (tumor supplied group of factor) in early diagnosing and predicting in patients with NPC.

METHOD

EBV-IgA and level of TSGF were measured before therapy and 1 month, 1 year after therapy in 35 patients with NPC, and the relationship between them was researched.

RESULT

The diagnostic sensitivity of TSGF and EBV-IgA was 91%, 97% respectively, there is no significant relation between them. After treatment, the level of TSGF in PD (progression disease) patient remained higher, but had a significantly drop in RR(including the CR, PR and SI)) patient.

CONCLUSION

Results suggested that TSGF may be useful in diagnosing and prediction of NPC.

The solubility of gases and vapours in dry octan-1-ol at 298 K

Ostwald solubility coefficients of 74 compounds in dry octan-1-ol at 298 K have been determined, and have been combined with literature values and additional values we have calculated from solubilities in dry octan-1-ol and vapour pressures to yield a total of 161 log L(OctOH) values at 298 K. These L(OctOH) values are identical to gas-to-dry octan-1-ol partition coefficients, often denoted as K(OA). Application of the solvation equation of Abraham to 124 values as a training set yielded a correlation equation with n = 124, S.D. = 0.125, r2 = 0.9970 and F = 7731. This equation was then used to predict 32 values of log L(OctOH) as a test set, giving a standard deviation, S.D. of 0.131, an average absolute deviation of 0.085 and an average deviation of -0.009 log units. The solvation equation for the combined 156 log L(OctOH) values was log L(OctOH) = -0.120 - 0.203R2 + 0.560pi2(H) + 3.560 sum(alpha2(H)) + 0.702 sum(beta2(H)) + 0.939 logL16, n =156, r2 = 0.9972, S.D. = 0.125, F = 10573, where, n is the number of data points (solutes), r the correlation coefficient, S.D. the standard deviation and F is the F-statistic. The independent variables are solute descriptors as follows: R2 is an excess molar refraction, pi2(H) the dipolarity/polarisability, sum(alpha2(H)) the overall or summation hydrogen-bond acidity, sum(beta2(H)) the overall or summation hydrogen-bond basicity and L16 is the Ostwald solubility coefficient on hexadecane at 298 K. The equation is consistent with similar equations for the solubility of gases and vapours into methanol, ethanol and propan-1-ol. It is suggested that the equation can be used to predict further values of log L(OctOH), for which the solute descriptors are known, to within 0.13 log units.

A comparison of F-actin labeling methods for light microscopy in different plant specimens: multiple techniques supplement each other

Different detection methods for F-actin labeling were compared on a range of plant specimens: cultured cells, whole organ mounts and sectioned material. For cultured cells, microinjection of labeled phalloidin yielded the most detailed picture but careful permeation methods come close, while immunocytochemical methods always gave relatively poor detail, especially on the level of the fine filaments. For whole organ mounts and sectioned material, permeation methods and immunolocalization are the methods of choice, however never reaching the level of resolution of permeation methods in single cells. It is clear that there is no general and universal good method and multiple techniques are needed, especially when working with different specimens and with different aims.

Fc receptor-mediated phagocytosis makes a significant contribution to clearance of influenza virus infections

Fc receptors for IgG expressed on macrophages and NK cells are important mediators of opsonophagocytosis and Ab-dependent cell-mediated cytotoxicity. Phagocyte-mediated opsonophagocytosis is pivotal for protection against bacteria, but its importance in recovery from infection with intracellular pathogens is unclear. We have now investigated the role of opsonophagocytosis in protection against lethal influenza virus infection by using FcR gamma(-/-) mice. Absence of the FcR gamma-chain did not affect the expression of IFN-gamma and IL-10 in the lungs and spleens after intranasal immunization with an influenza subunit vaccine. Titers of serum and respiratory Abs of the IgM, IgG1, IgG2a, and IgA isotypes in FcR gamma(-/-) mice were similar to levels seen in FcR gamma(+/+) mice. Nevertheless, FcR gamma(-/-) mice were highly susceptible to influenza infection, even in the presence of anti-influenza Abs from immune FcR gamma(+/+) mice. NK cells were not necessary for the observed Ab-mediated viral clearance, but macrophages were found to be capable of actively ingesting opsonized virus particles. We conclude that Fc receptor-mediated phagocytosis plays a pivotal role in clearance of respiratory virus infections.

The epithelium-specific ETS protein EHF/ESE-3 is a context-dependent transcriptional repressor downstream of MAPK signaling cascades

Exon trapping and cDNA selection procedures were used to search for novel genes at human chromosome 11p13, a region previously associated with loss of heterozygosity in epithelial carcinomas. Using these approaches, we found the ESE-2 and ESE-3 genes, coding for ETS domain-containing transcription factors. These genes lie in close proximity to the catalase gene within a approximately 200-kilobase genomic interval. ESE-3 mRNA is widely expressed in human tissues with high epithelial content, and immunohistochemical analysis with a newly generated monoclonal antibody revealed that ESE-3 is a nuclear protein expressed exclusively in differentiated epithelial cells and that it is absent in the epithelial carcinomas tested. In transient transfections, ESE-3 behaves as a repressor of the Ras- or phorbol ester-induced transcriptional activation of a subset of promoters that contain ETS and AP-1 binding sites. ESE-3-mediated repression is sequence- and context-dependent and depends both on the presence of high affinity ESE-3 binding sites in combination with AP-1 cis-elements and the arrangement of these sites within a given promoter. We propose that ESE-3 might be an important determinant in the control of epithelial differentiation, as a modulator of the nuclear response to mitogen-activated protein kinase signaling cascades.

Evaluation of human intestinal absorption data and subsequent derivation of a quantitative structure–activity relationship (QSAR) with the Abraham descriptors

The human intestinal absorption of 241 drugs was evaluated. Three main methods were used to determine the human intestinal absorption: bioavailability, percentage of urinary excretion of drug-related material following oral administration, and the ratio of cumulative urinary excretion of drug-related material following oral and intravenous administration. The general solvation equation developed by Abraham's group was used to model the human intestinal absorption data of 169 drugs we considered to have reliable data. The model contains five Abraham descriptors calculated by the ABSOLV program. The results show that Abraham descriptors can successfully predict human intestinal absorption if the human absorption data is carefully classified based on solubility and administration dose to humans.

Fate and toxicity of endosulfan in Namoi River water and bottom sediment

Endosulfan (6,7,8,9,10,10,-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepine-3-oxide) sorption (standardized to 1% total organic carbon and dry weight) was significantly (P < 0.05) more concentrated on the large (>63 microm) particle fraction compared with smaller size fractions (<5 microm and 5-24 microm) of bottom sediments from the Namoi River, Australia. Following completion of the particle size fractionation (6 to 12 wk) and a sediment toxicity assessment (2 wk), the sediments showed large decreases in concentrations of alpha-endosulfan that coincided with an increase in endosulfan sulfate concentrations and minimal changes in beta-endosulfan concentrations. In the Namoi River, similar patterns were observed in the composition of total endosulfan in monthly measurements of bottom sediments and in passive samplers placed in the water column following runoff from cotton (Gossypium hirsutum L.) fields. The toxicity of endosulfan sulfate in river water indicated by the nymphs of the epibenthic mayfly Jappa kutera, was more persistent than the alpha- and beta-endosulfan parent isomers due to its longer half-life. This suggests that endosulfan sulfate would contribute most to previously observed changes in population densities of aquatic biota. Measured concentrations of total endosulfan in river water of up to 4 microg L(-1) following storm runoff, exceed the range of the 96-h median lethal concentration (LC50) values in river water for both alpha-endosulfan (LC50 = 0.7 microg L(-1); 95% confidence interval [CI] = 0.5 to 1.1) and endosulfan sulfate (LC50 = 1.2 microg L(-1); 95% CI = 0.4 to 3.3). In contrast, the 10-d LC50 value for total endosulfan in the sediment toxicity test (LC50 = 162 microg kg(-1); 95% CI = 120 to 218 microg kg(-1)) was more than threefold higher than the highest measured concentration of total endosulfan in field samples of bottom sediment (48 microg kg(-1)). This suggests that pulse exposures of endosulfan in the water column following storm runoff may be more acutely toxic to riverine biota than in contaminated bottom sediment.

Implanon: a critical review

OBJECTIVE

To evaluate clinical information on Implanon as a long-term method of contraception and, specifically, to review the efficacy and adverse effect profile of Implanon.

DATA SOURCES

A MEDLINE search (from 1966 through June 1999) was performed to retrieve primary and review articles. The search was limited to data on human subjects. Some references were identified through secondary sources.

STUDY SELECTION AND DATA EXTRACTION

Pharmacokinetic and pharmacodynamic studies, and clinical trials assessing the efficacy and safety of desogestrel implants were reviewed. Relevancy and consistency of information was assessed for each trial.

DATA SYNTHESIS

Implanon is the newest contraceptive implant system that has completed worldwide Phase III clinical trials. It is a single rod that contains a core of 68 mg of 3-keto-desogestrel with a membrane of ethylene vinyl acetate. Inhibition of ovulation occurs within one day of implantation, and effective contraception lasts for three years. Fertility returns within one month after implant removal. Insertion and removal by trained medical professionals is simple, and only minor complications have been documented. Adverse effects are mild and primarily consist of abnormal bleeding, weight gain, acne, breast pain, and headache.

CONCLUSIONS

The data on Implanon indicate that it provides effective long-term contraception with limited adverse effects. It appears to be a good addition to the currently available contraceptives.

[Protective effect of erigeron injections on hepatotoxicity induced by intestinal ischemia-reperfusion in mice]

The liver injury was induced by intestinal ischemia-reperfusion and the protective effect of erigeron injection (EI) was studied in mice. The results showed that serum alanine transaminase (ALT) and glutathione S-transferase (GST) activity increased while the root of superior mesenteric artery was blocked with non-injury artery clap for 20 minute and reperfusion for 1 hour. EI could protect the above changes induced by intestinal ischemia-reperfusion. EI could reduce the activities of serum ALT and GST, decrease the content of hepatic MDA and significantly increase the activity of SOD. The pathological changes of hepatocytes induced by intestinal ischemia-reperfusion were less in EI groups. These results suggested that EI could protect the liver of mice from injury induced by intestinal ischemia-reperfusion. One of the mechanisms of hepatoprotective action was related to the antioxidative function of erigeron.

IgA immunodeficiency leads to inadequate Th cell priming and increased susceptibility to influenza virus infection

IgA is considered to be the principal Ab involved in defense against pathogens in the mucosal compartment. Using mice with a targeted disruption in IgA gene expression (IgA(-/-) mice), we have examined the precise role of IgA in protective anti-influenza responses after intranasal vaccination. IgA(-/-) mice immunized intranasally with soluble hemagglutinin (hemagglutinin subtype 1) and neuraminidase (neuraminidase subtype 1) vaccine in the absence of adjuvant were found to be more susceptible to influenza virus infection than IgA(+/+) mice (13 vs 75% survival after virus challenge). Inclusion of IL-12 during immunization restored the protective efficacy of the vaccine to that seen in IgA(+/+) animals. IgA(-/-) mice had no detectable IgA expression, but displayed enhanced serum and pulmonary IgM and IgG Ab levels after IL-12 treatment. Assessment of T cell function revealed markedly depressed splenic lymphoproliferative responses to PHA in IgA(-/-) animals compared with IgA(+/+) mice. Furthermore, IgA(-/-) animals displayed impaired T cell priming to the H1N1 subunit vaccine, with concomitant reduction in recall memory responses due to a defect in APC function. Collectively, these results provide evidence that a major role of IgA is to facilitate presentation of Ag to mucosal T cells. IL-12 treatment can overcome IgA deficiency by providing adequate T cell priming during vaccination.

Development of disulfide peptide mapping and determination of disulfide structure of recombinant human osteoprotegerin chimera produced in Escherichia coli

Recombinant human osteoprotegerin chimera is a 90-kDa protein containing a human IgG Fc domain fused to human osteoprotegerin. The molecule is a dimer linked by two intermolecular disulfide bonds and contains eleven intramolecular disulfide bonds per monomer. A cysteine-rich region in osteoprotegerin contains nine disulfide bridges homologous to the cysteine-rich signature structure of the tumor necrosis factor receptor/nerve growth factor receptor superfamily. In this report, we have developed peptide mapping procedures suitable to generate disulfide-containing peptides for disulfide structure assignment of the fusion molecule. The methods employed included proteolytic digestion using endoproteinases Glu-C and Lys-C in combination followed by LC-MS analyses. Disulfide linkages of peptide fragments containing a single disulfide bond were assigned by sequence analysis via detection of (phenylthiohydantoinyl) cystine and/or by MS analysis. Disulfide bonds of a large, core fragment containing three peptide sequences linked by four disulfides were assigned after generation of smaller disulfide-linked peptides by a secondary thermolysin digestion. Disulfide structures of peptide fragments containing two disulfide bonds were assigned using matrix-assisted laser desorption ionization mass spectrometry with postsource decay. Both the inter- and intramolecular disulfide linkages of the chimeric dimer were confirmed.

Negative regulation of lymphocyte activation and autoimmunity by the molecular adaptor Cbl-b

The signalling thresholds of antigen receptors and co-stimulatory receptors determine immunity or tolerance to self molecules. Changes in co-stimulatory pathways can lead to enhanced activation of lymphocytes and autoimmunity, or the induction of clonal anergy. The molecular mechanisms that maintain immunotolerance in vivo and integrate co-stimulatory signals with antigen receptor signals in T and B lymphocytes are poorly understood. Members of the Cbl/Sli family of molecular adaptors function downstream from growth factor and antigen receptors. Here we show that gene-targeted mice lacking the adaptor Cbl-b develop spontaneous autoimmunity characterized by auto-antibody production, infiltration of activated T and B lymphocytes into multiple organs, and parenchymal damage. Resting cbl-b(-/-) lymphocytes hyperproliferate upon antigen receptor stimulation, and cbl-b(-/-) T cells display specific hyperproduction of the T-cell growth factor interleukin-2, but not interferon-gamma or tumour necrosis factor-alpha. Mutation of Cbl-b uncouples T-cell proliferation, interleukin-2 production and phosphorylation of the GDP/GTP exchange factor Vav1 from the requirement for CD28 co-stimulation. Cbl-b is thus a key regulator of activation thresholds in mature lymphocytes and immunological tolerance and autoimmunity.

Mineralization and alkaline phosphatase activity in collagen lattices populated by human osteoblasts

Adult human osteoblastic cells were grown in a native type I collagen gel. Proliferation and viability analyses showed that cells rapidly stopped dividing and became blocked in the G0G1 phase (91% on day 13). Carboxyfluorescein diacetate cell staining and flow cytometry showed that osteoblasts were viable for the first 16 days and then viability decreased (58% viable cells on day 22). Osteoblasts were able to retract the matrix. Betaglycerophosphate (betaGP) stimulated the deposition of mineral particles in the collagen network, and electron probe microanalysis showed that they were principally calcium and phosphorus, with a Ca/P ratio of about 1.7. Various times of betaGP supply were tested. We compared 10 mM betaGP added only once at day 0, or continuously from day 0, day 8, or day 21. Mineralization was observed in conditions where betaGP was added at day 0. Furthermore, 10 mM betaGP added once during gel preparation was sufficient to induce mineralization with mineral accumulation up to day 15 whereas the speed of the gel contraction decreased. In every condition, cultures expressed high alkaline phosphatase (ALP) levels as early as day 3, which decreased afterwards. These kinetics might explain why the other conditions did not prove favorable to the mineralization process. The model was used to study the influence of blocking gel retraction. Blocking retraction delayed the ALP activity decrease, but had no effect on mineralization. In conclusion, human adult osteoblasts cultured in native collagen gel stopped proliferation and underwent mineralization very early. This model should be used to investigate the influence of effectors on the early stages of culture.

Urine glycyl-L-proline increase and skin trophicity

Glycyl-L-proline (gly-pro) is an end product of collagen metabolism that is further cleaved by prolidase (EC 3.4.13.9); the resulting proline molecules are recycled into collagen or other proteins. We postulated a relationship between defective gly-pro hydrolysis, increased collagen degradation and skin destruction. This relationship was tested using HPLC to measure the gly-pro in urine. 24 hour urine samples were collected from 27 old people (86 +/- 6 years old), of whom 15 were suffering from skin pressure sores of the sacrum or calcaneus. The urine from patients with pressure sores contained significantly more gly-pro than the urine from the control. A cut-off at 7 mumol/mmol creatinine gave the test a positive predictive value of 70%. Collagen breakdown was also increased as indicated by the increase of hydroxyproline (hyp) in the urine. But this breakdown seemed to stop at the gly-pro step.

The correlation and prediction of the solubility of compounds in water using an amended solvation energy relationship

The aqueous solubility of liquids and solids, as log S(W), has been correlated with an amended solvation equation that incorporates a term in Sigma alpha(2)(H) x Sigma beta(2)(H), where the latter are the hydrogen bond acidity and basicity of the solutes, respectively. Application to a training set of 594 compounds led to a correlation equation with a standard deviation, SD, of 0.56 log units. For a test set of 65 compounds, the SD was 0.50 log units, and for a combined correlation equation for 659 compounds, the SD was 0.56 log units. The correlation equations enable the factors that influence aqueous solubility to be revealed. The hydrogen-bond propensity of a compound always leads to an increase in solubility, even though the Sigma alpha(2)(H) x Sigma beta(2)(H) term opposes solubility due to interactions in the liquid or solid. Increase in solute dipolarity/polarizability increases solubility, whereas an increase in solute excess molar refraction, and especially, volume decrease solubility. The solubility of Bronsted acids and bases is discussed, and corrections for the fraction of neutral species in the saturated solution are graphically presented.

Electroencephalographic imaging of higher brain function

High temporal resolution is necessary to resolve the rapidly changing patterns of brain activity that underlie mental function. Electroencephalography (EEG) provides temporal resolution in the millisecond range. However, traditional EEG technology and practice provide insufficient spatial detail to identify relationships between brain electrical events and structures and functions visualized by magnetic resonance imaging or positron emission tomography. Recent advances help to overcome this problem by recording EEGs from more electrodes, by registering EEG data with anatomical images, and by correcting the distortion caused by volume conduction of EEG signals through the skull and scalp. In addition, statistical measurements of sub-second interdependences between EEG time-series recorded from different locations can help to generate hypotheses about the instantaneous functional networks that form between different cortical regions during perception, thought and action. Example applications are presented from studies of language, attention and working memory. Along with its unique ability to monitor brain function as people perform everyday activities in the real world, these advances make modern EEG an invaluable complement to other functional neuroimaging modalities.

A comparison of 15N proline and 13C leucine for monitoring protein biosynthesis in the skin

The tracers L 15N-proline and L(1-13C)-leucine were used to explore the synthesis of skin proteins in vivo in rabbits. They orally received a single dose containing an equimolecular mixture of L(1-13C)-leucine and L 15N-proline. The changes in the amounts of these tracers in blood and skin were monitored for a total of 8 h. The data showed the appearance of the two tracers in blood within 15 min and their clearance in 8 h. They were both rapidly (15 min) incorporated into skin proteins, but more proline was incorporated than leucine. We therefore consider L 15N-proline to be a better tracer than L(1-13C)-leucine for studying protein metabolism in the skin.

Deblurring

In most instances, traditional EEG methodology provides insufficient spatial detail to identify relationships between brain electrical events and structures and functions visualized by magnetic resonance imaging or positron emission tomography. This article describes a method called Deblurring for increasing the spatial detail of the EEG and for fusing neurophysiologic and neuroanatomic data. Deblurring estimates potentials near the outer convexity of the cortex using a realistic finite element model of the structure of a subject's head determined from their magnetic resonance images. Deblurring is not a source localization technique and thus makes no assumptions about the number or type of generator sources. The validity of Deblurring has been initially tested by comparing deblurred data with potentials measured with subdural grid recordings. Results suggest that deblurred topographic maps, registered with a subject's magnetic resonance imaging and rendered in three dimensions, provide better spatial detail than has heretofore been obtained with scalp EEG recordings. Example results are presented from research studies of somatosensory stimulation, movement, language, attention and working memory. Deblurred ictal EEG data are also presented, indicating that this technique may have future clinical application as an aid to seizure localization and surgical planning.

The oncogene product Vav is a crucial regulator of primary cytotoxic T cell responses but has no apparent role in CD28-mediated co-stimulation

The guanine nucleotide-exchange factor Vav is a regulator of antigen-mediated cytoskeletal reorganization required for receptor clustering, proliferation and thymic selection. Moreover, Vav has been identified as a major substrate in the CD28 signal transduction pathway and overexpression of Vav enhances TCR-mediated IL-2 secretion in T cells. Here we show that CD3- plus CD28-mediated proliferation and IL-2 production were reduced in vav gene-deficient T cells. However, Vav had no apparent role in phorbol 12-myristate 13-acetate-plus CD28-mediated proliferation and IL-2 production, suggesting that Vav acts downstream of the TCR/CD3 complex. In vivo, Vav expression was crucial to generate primary vesicular stomatitis virus (VSV)-specific cytotoxic T cell responses. In contrast, vav-/- mice exhibited a reduced but significant footpad swelling after lymphocytic choriomeningitis virus (LCMV) infections and mounted a measurable primary cytotoxic T cell response to LCMV. Upon in vitro restimulation, cytotoxic T cell responses of both VSV- and LCMV-infected mice reached near normal levels. Our data provide the first genetic evidence that Vav is an important effector molecule that relays antigen receptor signaling to IL-2 production and activation of cytotoxic T cells.

Geographic risk for lyme disease and human granulocytic ehrlichiosis in southern New York state

Ixodes scapularis, the tick vector of Lyme disease and human granulocytic ehrlichiosis (HGE), is prevalent in much of southern New York state. The distribution of this species has increased, as have reported cases of both Lyme disease and HGE. The unreliability of case reports, however, demonstrates the need for tick and pathogen surveillance in order to accurately define areas of high risk. In this study, a total of 89,550 m2 at 34 study sites was drag sampled in 1995 and a total of 51,540 m2 at 40 sites was sampled in 1996 to determine tick and pathogen distribution in southern New York state. I. scapularis was collected from 90% of the sites sampled, and regionally, a 2.5-fold increase in nymphal abundance occurred from 1995 to 1996. I. scapularis individuals from all sites were infected with Borrelia burgdorferi in 1995, while an examination of ticks for both B. burgdorferi and the agent of HGE in 1996 confirmed that these organisms were present in all counties; the average coinfection rate was 1.9%. No correlation was found between estimated risk and reported cases of Lyme disease. The geographic disparity of risk observed among sites in this study underscores the need for vector and pathogen surveillance on a regional level. An entomologic risk index can help identify sites for targeted tick control efforts.

19-nor vitamin-D analogs: a new class of potent inhibitors of proliferation and inducers of differentiation of human myeloid leukemia cell lines

We have studied the in vitro biological activities and mechanisms of action of 1,25-dihydroxyvitamin D3 (1,25D3) and nine potent 1,25D3 analogs on proliferation and differentiation of myeloid leukemia cell lines (HL-60, retinoic acid-resistant HL-60 [RA-res HL-60], NB4 and Kasumi-1). The common novel structural motiff for almost all the analogs included removal of C-19 (19-nor); each also had unsaturation of the side chain. All the compounds were potent; for example, the concentration of analogs producing a 50% clonal inhibition (ED50) ranged between 1 x 10(-9) to 4 x 10(-11) mol/L when using the HL-60 cell line. The most active compound [1, 25(OH)2-16,23E-diene-26-trifluoro-19-nor-cholecalciferol (Ro 25-9716)] had an ED50 of 4 x 10(-11) mol/L; in contrast, the 1,25D3 produced an ED50 of 10(-9) mol/L with the HL-60 target cells. Ro 25-9716 (10(-9) mol/L, 3 days) was a strong inducer of myeloid differentiation because it caused 92% of the HL-60 cells to express CD11b and 75% of these cells to reduce nitroblue tetrazolium (NBT). This compound (10(-8) mol/L, 4 days) also caused HL-60 cells to arrest in the G1 phase of the cell cycle (88% cells in G1 v 48% of the untreated control cells). The p27(kip-1), a cyclin-dependent kinase inhibitor which is important in blocking the cell cycle, was induced more quickly and potently by Ro 25-9716 (10(-7) mol/L, 0 to 5 days) than by 1,25D3, suggesting a possible mechanism by which these analogs inhibit proliferation of leukemic growth. The NB4 promyelocytic leukemia cells cultured with the Ro 25-9716 were also inhibited in their clonal proliferation (ED50, 5 x 10(-11) mol/L) and their expression of CD11b was enhanced (80% positive [10(-9) mol/L, 4 days] v 27% untreated NB4 cells). Moreover, the combination of Ro 25-9716 (10(-9) mol/L) and all-trans retinoic acid (ATRA, 10(-7) mol/L) induced 92% of the NB4 cells to reduce NBT, whereas only 26% of the cells became NBT positive after a similar exposure to the combination of 1,25D3 and ATRA. Surprisingly, Ro 25-9716 also inhibited the clonal growth of poorly differentiated leukemia cell lines (RA-res HL-60 [ED50, 4 x 10(-9) mol/L] and Kasumi-1 [ED50, 5 x 10(-10) mol/L]). For HL-60 cells, Ro 25-9716 markedly decreased the percent of the cells in S phase of the cell cycle and increased the expression of the cyclin-dependent kinase inhibitor, p27(kip-1). In summary, 19-nor vitamin D3 compounds strongly induced differentiation and inhibited clonal proliferation of various myeloid leukemia cell lines, suggesting a therapeutic niche for their use in myeloid leukemia.

A rapid method for determining standard 10/10 electrode positions for high resolution EEG studies

This report describes the basic principle and examines the comparative accuracy of a novel method for locating 3-D coordinates of electrode positions on the head. The method involves calculation of the 3-D coordinates for any array of 10/10 electrode positions from 14 straight-line distances between 11 10/10 electrodes. In 11 subjects the 3-D coordinates of 64 scalp electrodes embedded in an electrode cap were identified with the novel method, and also with a standard commercial magnetic field digitizer. The outcomes from the two methods were compared with directly measured coordinates of all 64 positions (cf. De Munck, J.C., Vijn, P.C.M. and Spekreijse, H. A practical method for determining electrode positions on the head. Electroenceph. clin. Neurophysiol., 1991, 89: 85-87). Coordinates in 3 dimensions obtained using the new method were significantly closer to the directly measured values than those from the magnetic field digitizer. The new method was also quicker and requires less specialized instrumentation than the magnetic field digitization method. The novel method appears to be a valid and convenient tool for use with EEG analysis techniques that require specific information about 10/10 electrode positions.

Morphological alteration of fibroblasts mechanically stressed in a collagen lattice

The behavior of fibroblast-populated collagen lattices under mechanical stress was studied. Lattice retraction was blocked to allow the application of mechanical stress by contraction of the fibroblasts against the fixed ends of the lattice. The forces were modulated by varying the collagen/fibroblast ratio and the amount of collagen fibrils produced, by which the forces were transmitted. Transmission electron microscopy showed several disturbances of fibroblast ultrastructure, with empty and full vacuoles, lamellar bodies and signs of cytolysis. It is suggested that the morphological alterations in the fibroblasts may constitute a feedback reaction to the mechanical stress.

Effects of potent vitamin D3 analogs on clonal proliferation of human prostate cancer cell lines

BACKGROUND

Management of prostate cancer that has spread outside of the prostate capsule is a difficult problem. Innovative, non-toxic approaches to the disease are required. New, relatively non-toxic vitamin D3 analogs have recently been synthesized. We report that several of these compounds have marked antiproliferative effects on prostate cells.

METHODS

The clonal antiproliferative activity of five novel analogs of 1,25 dihydroxyvitamin D3 [1,25(OH)2D3, (cmpd C)] as well as 1,25(OH)2D3 itself was tested on three human prostate cancer cell lines (PC-3, LNCaP, and DU-145). The analogs were 20-epi-22oxa-24a,26a,27a-tri-homo-1 alpha,25(OH)2D3 (code name: KH 1060); 24a26a27a-tri-homo-22,24-diene-1 alpha,25(OH)2D3 (code name: EB 1089); 1,25(OH)2-16ene-D3 (code name: HM); 1,25(OH)2-16ene-23yne-D3 (code name: V); 1,25(OH)2-20-epi-D3 (code name: MC 1288)].

RESULTS

With the parent compound [1,25(OH)2D3], the effective dose that inhibited 50% clonogenic growth of PC-3 and LNCaP was 10(-8)M and 7 x 10(-9)M, respectively. For these prostate cancer cell lines, KH 1060 was the most potent analog by an order of 25- to 35-fold as compared to cmpd C. The second and third most potent analogs were HM and MC 1288. DU-145 was resistant to all the vitamin D3 analogs. The major side-effect of 1,25(OH)2D3 is the production of hypercalcemia. The relative inhibitory index (RII) was determined by comparing the antiproliferative activity of the analog to its ability to produce hypercalcemia in mice injected intraperitoneally every other day. The KH 1060 had the best RTI: 50- to 70-fold greater than 1,25(OH)2D3 for PC-3 and LNCaP, respectively.

CONCLUSIONS

A trial of one or more of these innovative compounds should be considered for treatment of minimal residual disease of prostate cancer.

Synergistic decrease of clonal proliferation, induction of differentiation, and apoptosis of acute promyelocytic leukemia cells after combined treatment with novel 20-epi vitamin D3 analogs and 9-cis retinoic acid

Patients with acute promyelocytic leukemia (APL) usually relapse after all-trans retinoic acid (RA) treatment because this therapy fails to eradicate the malignant clone. Our data showed that KH 1060 and other 20-epi vitamin D3 analogs alone were potent inhibitors of clonal growth of NB4 cells, an APL cell line (ED50, approximately 5 x 10(-11) M). The combination of KH 1060 and 9-cis-RA synergistically and irreversibly enhanced this effect. Neither KH 1060 nor 9-cis-RA (10(-6) M, 3 d) were strong inducers of differentiation of NB4 cells. However, 98% of the cells underwent differentiation to a mature phenotype with features of both granulocytes and monocytes after exposure to a combination of both compounds. Apoptosis only increased after incubation of NB4 cells with 9-cis-RA alone (28%) or with a combination of 9-cis-RA plus KH1060 (32%). Immunohistochemistry showed that the bcl-2 protein decreased from nearly 100% of the wild-type NB4 cells to 2% after incubation with a combination of KH 1060 and 9-cis-RA, and the bax protein increased from 50% of wild-type NB4 cells to 92% after culture with both analogs (5 x 10(-7) M, 3 d). Western blot analysis paralleled these results. Studies of APL cells from one untreated individual paralleled our results with NB4 cells. Taken together, the data demonstrated that nearly all of the NB4 cells can be irreversibly induced to differentiate terminally when exposed to the combination of KH 1060 and 9-cis-RA.

Glial cell line-derived neurotrophic factor: selective reduction of the intermolecular disulfide linkage and characterization of its disulfide structure

Glial cell line-derived neurotrophic factor is a protein known to enhance the survival of dopaminergic neurons against several neurotoxins. It has been shown to have therapeutic potential in the treatment of Parkinson's disease and other neurodegenerative diseases. We have determined the inter- and intramolecular disulfide linkages of the dimeric molecule by a combination of direct peptide analysis and peptide analysis after either partial reduction or partial oxidation of the protein. Under an acidic condition, the interchain disulfide bond was selectively cleaved with tris(2-carboxyethyl)phosphine, revealing that Cys101 was involved in the intermolecular disulfide linkage. Three other disulfides, Cys68-Cys131, Cys72-Cys133, and Cys41-Cys102, were identified as intramolecular linkages. The determined disulfide structure is highly homologous to that of transforming growth factor beta 2. Since one intramolecular disulfide points through a ring consisting of eight amino acid residues based on the similarity with transforming growth factor beta 2, the disulfide-linked peptides were not purified by conventional methods. Only the peptides from an N-terminal region (residues -1 to 37) were liberated by proteolytic treatment with trypsin or endoproteinase Lys-C, resulting in a stable cystine-knot protein.

Disulfide structure and N-glycosylation sites of an extracellular domain of granulocyte-colony stimulating factor receptor

An extracellular domain containing 603 amino acid residues of human granulocyte-colony stimulating factor receptor was expressed in Chinese hamster ovary cells. The affinity-purified material has previously been shown to dimerize when combined with the ligand. In this paper we have characterized the primary structure of this active receptor. Laser desorption mass spectrometry of the purified receptor showed a broad peak at a molecular weight of 84,000, ranging from 77,000 to 91,000. The molecular weight heterogeneity is due to glycosylation. Since the molecular weight based on the amino acid sequence is 67,322, by subtraction the carbohydrate content is approximately 17,000. Disulfide structure of the receptor was determined by peptide mapping in the absence and presence of reducing agent. Sequence and mass spectral analyses of these peptides showed the receptor to contain eight disulfide bonds and three free cysteines. These disulfide bonds are consistent with the known domain motifs of the receptor in that no interdomain disulfides were present. One of the three free cysteines is reactive with alkylating agents, while the others are less reactive, probably being buried in the interior of the molecule. Blocking the free cysteines did not affect the ligand binding. Carbohydrate moieties are somewhat evenly spaced throughout the molecule, at eight different N-glycosylation sites, some of which show heterogeneity in their compositions. Glycosylation seems necessary for stabilizing the molecule against disulfide-linked oligomerization of the receptor, indicating that the free cysteine residues become reactive for oxidation and disulfide exchange upon deglycosylation.

Combination of a potent 20-epi-vitamin D3 analogue (KH 1060) with 9-cis-retinoic acid irreversibly inhibits clonal growth, decreases bcl-2 expression, and induces apoptosis in HL-60 leukemic cells

All-trans retinoic acid (RA) is the first highly effective differentiation-inducing agent for remission induction in patients with acute promyelocytic leukemia. However, remissions are short-lived because the treatment fails to induce complete differentiation and fails to eradicate the malignant clone. To eliminate rapidly the malignant clone, in analogy with aggressive chemotherapy, the combination of potent differentiation- and apoptosis-inducing drugs working through different receptors and signal pathways may be useful. The active form of vitamin D3 (1,25-dihydroxyvitamin D3; 1,25(OH)2D3) inhibits proliferation and induces differentiation of myeloid leukemic cells. The 9-cis-RA, unlike all-trans-RA which binds only retinoic acid receptors, is a high affinity ligand for both retinoic acid receptors and retinoid X receptors. The aim of this study was to evaluate the therapeutic potential of combining a vitamin D(3) analogue, 20-epi-22-oxa-24a,26a,27a-tri-homo-1alpha,25(OH) 2D, (KH 1060), which belongs to the family of potent 20-epi-1,25(OH),D3 analogues, with 9-cis-RA by assessing their effects on the proliferation, differentiation, and apoptosis of the human leukemia cell line HL-60 in vitro. Our data show that KH 1060 alone is a very potent inhibitor of clonal proliferation of HL-60, but this effect is reversible, and that 9-cis-RA alone is a weak inhibitor of clonal proliferation of HL-60 cells. In contrast, the combination of KH 1060 and 9-cis-RA synergistically and irreversibly inhibited the clonal proliferation of HL-60 cells and induced apoptosis, as detected by morphological changes and DNA fragmentation. This combination also affected the expression of apoptosis-related genes. The bcl-2 protein became nearly undetectable, and expression of bax protein increased slightly (the bax:bcl-2 ratio was 14-fold higher than in untreated cells). Differentiation of treated HL-60 cells was assessed by their ability to produce superoxide, as measured by reduction of nitro blue tetrazolium, positive staining for alpha-naphthyl acetate esterase, phagocytosis, morphology, and analysis of membrane-bound differentiation markers with two-color immunofluorescence. Treatment with the combination of KH 1060 and 9-cis-RA was a potent inducer of differentiation of HL-60, with the cells developing a myelomonocytic phenotype. In summary, our data demonstrate that the combination of both KH 1060 and 9-cis-RA irreversibly and synergistically inhibited clonal growth, induced differentiation and apoptosis of HL-60 cells concomitantly with a very marked decreased expression of bcl-2, and increased the bax:bcl-2 ratio. This drug combination may have important therapeutic significance.

Human neurotrophin-3: a one-step peptide mapping method and complete disulfide characterization of the recombinant protein

Human neurotrophin-3 (NT-3) is a member of the nerve growth factor (NGF) family of neurotrophic factors, and the recombinant protein is being developed as a therapeutic for neurodegenerative diseases. The final product purity and lot-to-lot variation are monitored routinely by peptide mapping. However, only the N-terminal region of NT-3 was susceptible to proteolysis under native conditions. Complete digestion required that the protein be chemically modified by reduction and S-alkylation prior to proteolysis. Complete proteolytic degradation of the protein was achieved simply by an initial denaturation of NT-3 in 6 M guanidinium chloride (pH6) for 2 hr at 37 degrees C, followed by a tenfold dilution with the digestion buffer (0.1 M Tris-HCl, 1 mM CaCl2 at pH 7.0) and immediate addition of chymotrypsin at 1% by weight. Direct comparison of the peptide map with an identical aliquot that had been reduced and alkylated also allowed the establishment of the cystine linkages present in NT-3: Cys14 to Cys79, Cys57 to Cys108, and Cys67 to Cys110. This disulfide structure is homologous to the NGF family of neurotrophic factors.

High resolution evoked potential imaging of the cortical dynamics of human working memory

High resolution evoked potentials (EPs), sampled from 115 channels and spatially sharpened with the finite element deblurring method, were recorded from 8 subjects during working memory (WM) and control tasks. The tasks required matching each stimulus with a preceding stimulus on either verbal or spatial attributes. All stimuli elicited a central P200 potential that was larger in the spatial tasks than in the verbal tasks, and larger in the WM tasks than in the control tasks. Frequent, non-matching stimuli elicited a frontal, positive peak at 305 msec that was larger in the spatial WM task relative to the other tasks. Irrespective of whether subjects attended to verbal or spatial stimulus attributes, non-matching stimuli in the WM tasks also elicited an enhanced P450 potential over the left frontal cortex, followed by a sustained potential over the superior parietal cortex. A posterior P390 potential elicited by infrequent, matching stimuli was smaller in amplitude for both spatial and verbal WM tasks compared to control tasks, as was a central prestimulus CNV. These results indicate that WM is a function of a distributed system with both task-specific and task-independent components. Lesion studies and course temporal resolution functional imaging methods, such as PET and fMRI, tend to paint a fairly static picture of the cortical regions which participate in the performance of WM tasks. In contrast, the fine-grain time resolution provided by imaging brain function with EP methods provides a dynamic picture of subsecond changes in the spatial distribution of WM effects over the course of individual trials, as well as evidence for differences in the activity elicited by matching and non-matching stimuli within sequences of trials. This information about the temporal dynamics of WM provides a critical complement to the fine-grain spatial resolution provided by other imaging modalities.

Extracellular domain of granulocyte-colony stimulating factor receptor. Interaction with its ligand and identification of a domain in close proximity of ligand-binding region

An extracellular domain of human granulocyte-colony stimulating factor (G-CSF) receptor was expressed in and purified from Chinese hamster ovary cells. Complex formation between G-CSF and the receptor was studied by size exclusion chromatography, followed by chemical cross-linking. The receptor-ligand complex contained an equimolar ratio of each protein. Crosslinking experiments using disucciniimide suberate revealed that the native complex contained at least two types of cross-linked complexes; one form contained one or two G-CSF molecules per receptor molecule, whereas another form contained one or two G-CSF per two receptor molecules. The tryptic peptide map of the cross-linked complex provided a unique peptide peak which was not found in a peptide map of the original protein. Sequence analysis and mass spectrometry of the peptide indicated that two peptides were covalently linked by cross-linker, one peptide from G-CSF and the other from the receptor. In the cross-linked peptide, Lys-242 of the receptor cross-linked the amino terminal Met of G-CSF through the cross-linker. It was also shown that the N-terminal Met of G-CSF was readily acetylated in the receptor-ligand complex, indicating that it was not directly involved in receptor binding. The results show that the N-terminal Met of G-CSF is located at a distance of approximately 11 A from a reactive Lys-242 of the receptor in the ligand-receptor complex.

Mapping cognitive brain function with modern high-resolution electroencephalography

High temporal resolution is necessary to resolve the rapidly changing patterns of brain activity that underlie mental function. While electroencephalography (EEG) provides temporal resolution in the millisecond range, which would seem to make it an ideal complement to other imaging modalities, traditional EEG technology and practice provides insufficient spatial detail to identify relationships between brain electrical events and structures and functions that are visualized by magnetic resonance imaging (MRI) or positron emission tomography (PET). Recent advances overcome this problem by recording EEGs from more electrodes, by registering EEG data with anatomical information from each subject's MRI, and by correcting the distortion that is caused by volume conduction of EEG signals through the skull and scalp. Along with its ability to record how brains think when performing everyday activities in the real world, these advances make modern EEG an invaluable complement to other functional neuroimaging modalities.

Extracellular domain of neurotrophin receptor trkB: disulfide structure, N-glycosylation sites, and ligand binding

An extracellular domain of a human neurotrophin receptor trkB was expressed in Chinese hamster ovary cells and isolated as a glycoprotein possessing binding activity for brain-derived neurotrophic factor. The extracellular domain contains 398 amino acids and has a molecular weight of 60.6 kDa according to laser desorption mass spectrometry, indicating that the extracellular domain of trkB contains 33.3% carbohydrate moieties. Six disulfide linkages were determined to be Cys1-Cys7, Cys5-Cys14, Cys121-Cys145, Cys123-Cys163, Cys187-Cys235, and Cys271-Cys314, respectively. Cys300 was detected as a free sulfhydryl residue. Cysteine clusters 1 and 2 located in the N-terminal domain possess a similar type of disulfide structure and two other disulfide bonds in the C-terminal region are homologous to that of the Ig-like C2 domain. Among 12 potential N-linked glycosylation sites proposed in the soluble domain of trkB, 10 sites are actually glycosylated.

Towards measurement of brain function in operational environments

In operational environments that demand sustained vigilance or that involve multiple tasks competing for limited attentional resources, continuous monitoring of the mental state of the operator could decrease the potential for serious errors and provide valuable information concerning the ergonomics of the tasks being performed. There is widespread discussion and appreciation of the basic feasibility of utilizing neurophysiological measurements to derive accurate, reliable, rapid and unobtrusive assessments of mental state. However, progress in transitioning this idea into practical applications has been impeded by the fact that at present no convenient, inexpensive and effective means exists to derive a meaningful index of brain activity outside of laboratory settings. In this paper, we review some recent advances in recording technology and signal processing methods that will help overcome this limitation. For example, rapid progress is being made in the engineering of recording systems that are small, rugged, portable and easy-to-use, and thus suitable for deployment in operational environments. Progress is also being made in the development of signal processing algorithms for detecting and correcting recording artifacts and for increasing the amount of useful information that can be derived from brain signals. Finally, results from basic research studies suggest that accurate and reliable inferences about the mental load and alertness of an individual can be derived from neurophysiological measures in a practical fashion. These research and engineering successes suggest that it is reasonable to expect that in the near term a basic enabling technology will be deployed that will permit routine measurement of brain function in operational environments.

Alternative splicing of HLA class I transcripts induced by IFN-gamma and TNF in fibroblasts: release of soluble HLA class I heavy chain and an associate protein

FS-4 fibroblasts were found to produce 37-kDa HLA class I heavy chain in response to IFN-gamma or TNF in a time- and dose-dependent fashion, and a synergism between IFN-gamma and TNF was observed. Immunoprecipitation of IFN-gamma- or TNF-induced FS-4 cell culture supernatants by mAb A1.4 revealed an additional 33-kDa protein in association with the 37-kDa heavy chain. The 33-kDa protein appeared to be expressed in a 38-kDa form on the membrane of FS-4 cells induced by IFN-gamma or TNF, as A1.4 immunoprecipitated the 38-kDa band in association with the 44-kDa transmembrane HLA class I heavy chain. Release of the 37-kDa heavy chain could well be due to an alternative RNA splicing with the deletion of exon 5 encoding the hydrophobic transmembrane region of membrane-anchored HLA class I heavy chain. Northern blot analysis and S1 nuclease protection assay suggested the existence of HLA class I heavy chain mRNA lacking exon 5 in IFN-gamma- or TNF-induced FS-4 cells. Southern blot analysis on the products of reverse transcription-polymerase chain reaction amplification from cytoplasmic RNA confirmed induction of alternative splicing by these cytokines. Our results suggest that cytokine-induced production of soluble HLA class I molecules may play important roles in the regulation of T cell interaction with antigen-presenting cells.

Production of soluble HLA-class-I molecules by IFN-gamma-induced colon-adenocarcinoma cells

High levels of soluble HLA-class-I molecules (sHLA) were found to be produced in a time- and dose-dependent manner by colon-adenocarcinoma Colo205 cells in response to IFN-gamma stimulation. Among other cytokines tested, only IL-6, TNF, IFN-alpha and IFN-beta showed weak inducibility. IFN-gamma-induced production of sHLA was synergistically enhanced by IL-1 alpha, IL-6 or TNF, and combined treatment with TNF and IL-6 exhibited an additive to synergistic induction. Expression of sHLA is unlikely to result from IFN-gamma-induced enhancement of overall HLA-class-I expression, as at low concentrations IFN-alpha, IFN-beta and IFN-gamma stimulated increased expression of cell membrane HLA-class-I molecules in Colo205 cells with almost equal efficiency, whereas only IFN-gamma induced high level production of sHLA. Immunoblotting with a monoclonal antibody recognizing beta 2-microglobulin-free HLA-class-I heavy chain revealed 3 major forms of sHLA heavy chain, i.e., 45/43-, 37- and 33-kDa molecules, in the culture supernatants of IFN-gamma-induced Colo205 cells. The 45/43-kDa proteins can be partitioned into Triton X-114, representing intact HLA-class-I heavy chains shed from the cell membrane. The hydrophilic 37- and 33-kDa heavy chain, which remained almost exclusively in the aqueous phase after extraction with Triton X-114, could well be due to alternative RNA splicing, with deletion of exon 5 encoding the hydrophobic transmembrane region of membrane-anchored HLA-class-I heavy chain.

The mouse/human chimeric monoclonal antibody cA2 neutralizes TNF in vitro and protects transgenic mice from cachexia and TNF lethality in vivo

The pleiotropic cytokine tumour necrosis factor-alpha (TNF) is thought to play a central role in infectious, inflammatory and autoimmune diseases. Critical to the understanding and management of TNF-associated pathology is the development of highly specific agents capable of modifying TNF activity. We evaluated the ability of a high affinity mouse/human chimeric anti-TNF monoclonal antibody (cA2) to neutralize the in vitro and in vivo biological effects of TNF. cA2 inhibited TNF-induced mitogenesis and IL-6 secretion by human fibroblasts, TNF-priming of human neutrophils, and the stimulation of human umbilical vein endothelial cells by TNF as measured by the expression of E-selectin, ICAM-1 and procoagulant activity. cA2 also specifically blocked TNF-induced adherence of human neutrophils to an endothelial cell monolayer. Receptor binding studies suggested that neutralization resulted from cA2 blocking of TNF binding to both p55 and p75 TNF receptors on the cells. In vivo, repeated administration of cA2 to transgenic mice that constitutively express human TNF reversed the cachectic phenotype and prevented subsequent mortality. These results demonstrated that cA2 effectively neutralized a broad range of TNF biological activities both in vitro and in vivo.

Generation of nitric oxide and clearance of interferon-gamma after BCG infection are impaired in mice that lack the interferon-gamma receptor

Mice with a targeted deletion of either the interferon (IFN)-gamma gene or the IFN-gamma receptor gene (IFN-gamma R(0/0) mice) fail to survive infection with the Bacillus Calmette-Guerin (BCG) strain of Mycobacterium bovis. Here we show that resident peritoneal macrophages isolated 2 weeks after BCG infection from IFN-gamma R(0/0) mice produced significantly less nitric oxide (NO) than wild-type macrophages. However, the response to lipopolysaccharide (LPS) was not completely abrogated in the IFN-gamma R(0/0) macrophages. BCG infection of wild-type mice led to a marked increase in their urinary nitrite/nitrate levels, as previously described. This increase in urinary nitrite/nitrate was not detected in BCG- infected IFN-gamma R(0/0) mice, indicating that no other cytokine can replace IFN-gamma as a mediator of increased NO synthesis after BCG infection in the intact organism. A comparison of circulating levels of IFN-gamma in BCG-infected animals revealed that sera from IFN-gamma R(0/0) mice contained up to 66-fold more IFN-gamma than sera from identically treated wild-type mice. To determine if the higher levels of circulating IFN-gamma were due to increased IFN-gamma synthesis, we compared the amounts of IFN-gamma mRNA present in the spleens of BCG-infected wild-type and IFN-gamma R(0/0) mice. No increase in IFN-gamma mRNA levels was detected in the spleens from IFN-gamma R(0/0) mice. Since the generation of IFN-gamma protein in cultured spleen cells was also not increased in IFN-gamma R(0/0) mice, we conclude that clearance of IFN-gamma from the circulation is impaired in IFN-gamma R(0/0) mice, thus revealing a heretofore unrecognized important role for the IFN-gamma receptor in the regulation of IFN-gamma levels in the intact organism.

Targeted amplification of alternatively spliced transcripts of major histocompatibility complex class I heavy chain

The RPMI1788 cell line was found to produce soluble form of HLA class I molecules (sHLA) constitutively, due at least in part to an alternative splicing mechanism in which exon 5 of HLA class I heavy chain transcripts is deleted. Reverse transcription-polymerase chain reaction (RT-PCR) of cytoplasmic RNA of RPMI1788 cells using a pair of primers (A,B) complementary to the conserved sequences of HLA class I exon 4 and 6 yielded almost exclusively the full-length class I heavy chain cDNA. In order to amplify the alternatively spliced transcripts, primer C corresponding to the 5' boundary conserved region of exon 6 juxtaposed with three conserved nucleotides in 3' boundary region of exon 4 was synthesized. Using the primers A and C the spliced transcripts of RPMI1788 cells can be selectively or preferentially amplified by RT-PCR with three different DNA polymerases. Cloning and sequencing of the resulting cDNA confirmed that the spliced transcript lacks exon 5. The targeted amplification method may be useful and important for studies with respect to the regulation of class I sHLA expression and the mechanism by which alternative splicing of HLA class I heavy chain mRNA is induced.

Biological functions of IFN-gamma and IFN-alpha/beta: lessons from studies in gene knockout mice

Mice with a targeted disruption in the IFN-gamma receptor gene (IFN-gamma R0/0) provided a useful model to ask to what extent other cytokines could replace IFN-gamma in macrophage activation. In thioglycollate-elicited peritoneal macrophages from wild-typy (WT) mice, TNF enhanced nitric oxide (NO) release in the presence of IFN-gamma, though TNF alone was not effective. In macrophages from IFN-gamma R0/0 mice, which are not responsive to IFN-gamma, TNF completely failed to stimulate NO release. The NO inducing effects of IFN-alpha/beta were indistinguishable in IFN-gamma R0/0 and WT macrophages. The important role of IFN-gamma in the regulation of the induced expression of MHC class II antigen (Ia) was confirmed by showing that after systemic infection with the BCG strain of Mycobacterium bovis, peritoneal macrophages from IFN-gamma R0/0 mice had a lower level of Ia expression than macrophages from WT mice. BCG infection was not lethal for WT mice whereas all IFN-gamma R0/0 mice died 7-9 weeks after infection. It is well known that BCG infection greatly sensitizes mice to lethal action of LPS. Injection of LPS 2 weeks after BCG inoculation was significantly less lethal for IFN-gamma R0/0 mice than for WT mice. Reduced lethality of LPS correlated with a drastically reduced TNF-alpha production in the IFN-gamma R0/0 mice after BCG infection and LPS challenge. The greatly reduced ability of BCG-infected IFN-gamma R0/0 mice to produce TNF-alpha may be an important factor in their inability to resist BCG infection.(ABSTRACT TRUNCATED AT 250 WORDS)