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Previous work indicates that dynamic cerebral blood flow (CBF) regulation is impaired during hypercapnia; however, less is known about the impact of resting hypercapnia on regional CBF regulation during hypovolemia. Furthermore, there is disparity within the literature on whether differences between anterior and posterior CBF regulation exist during physiological stressors. We hypothesized: (a) lower-body negative pressure (LBNP)-induced reductions in cerebral blood velocity (surrogate for CBF) would be more pronounced during hypercapnia, indicating impaired CBF regulation; and (b) the anterior and posterior cerebral circulations will exhibit similar responses to LBNP. In 12 healthy participants (6 females), heart rate (electrocardiogram), mean arterial pressure (MAP; finger photoplethosmography), partial pressure of end-tidal carbon dioxide (PETCO2), middle cerebral artery blood velocity (MCAv) and posterior cerebral artery blood velocity (PCAv; transcranial Doppler ultrasound) were measured. Cerebrovascular conductance (CVC) was calculated as MCAv or PCAv indexed to MAP. Two randomized incremental LBNP protocols were conducted (− 20, − 40, − 60 and − 80 mmHg; three-minute stages), during coached normocapnia (i.e., room air), and inspired 5% hypercapnia (~ + 7 mmHg PETCO2 in normoxia). The main findings were: (a) static CBF regulation in the MCA and PCA was similar during normocapnic and hypercapnic LBNP trials, (b) MCA and PCA CBV and CVC responded similarly to LBNP during normocapnia, but (c) PCAv and PCA CVC were reduced to a greater extent at − 60 mmHg LBNP (P = 0.029; P

Hohlraums are hollow cylindrical cavities with high-Z material walls used to convert laser energy into uniform x-ray radiation drives for inertial confinement fusion capsule implosions and high energy density physics experiments. Credible computational modeling of hohlraums requires detailed modeling and coupling of laser physics, hydrodynamics, radiation transport, heat transport, and atomic physics. We report on improvements to Los Alamos National Laboratory's xRAGE radiation-hydrodynamics code in order to enable hohlraum modeling. xRAGE's Eulerian hydrodynamics and adaptive mesh refinement make it uniquely well suited to study the impacts of multiscale features in hohlraums. In order to provide confidence in this new modeling capability, we demonstrate xRAGE's ability to produce reasonable agreement with data from several benchmark hohlraum experiments. We also use xRAGE to perform integrated simulations of a recent layered high density carbon capsule implosion on the National Ignition Facility in order to evaluate the potential impacts of the capsule support tent, mixed cell conductivity methodologies, plasma transport, and cross-beam energy transfer (XBT). We find that XBT, seeded by plasma flows in the laser entrance hole (LEH), causes a slight decrease in energy coupling to the capsule and that all of these impact the symmetry of the x-ray drive such that they have an appreciable impact on the capsule implosion shape.

The engineered macro-pore foam provides a new way to study thermonuclear burn physics by utilizing capsules containing deuterated (D) foam and filling tritium (T) gas in the engineered macro-pores. The implosion of a thermonuclear capsule filled with an engineered macro-pore foam will be complex due to the interaction of a shock wave with the engineered macro-pores. It is our goal to quantify how substantially complex foam structures affect the shape of shock and bulk shock speed. A cylinder-shape shock tube experiment has been designed and performed at the Omega Laser Facility. In order to examine how a foam structure will affect shock propagation, we performed several tests varying (1) engineered macro-pore size, (2) average foam density, and (3) with/without neopentane (C5H12) gas. X-ray radiographic data indicate that shock speed through engineered macro-pore foams depends strongly on average foam density and less on pore size. Experimental shock propagation data helped guide two numerical simulation approaches: (1) a 2D simulation with homogenizing foams rather than explicitly simulating engineered macro-pores and (2) a 2D toroidal-pore approximation adopting a toroidal-tube geometry to model engineered macro-pores.

This paper presents the development of a predictive model for topside annulus vent gas flow from a flexible riser and the infrastructure to feed live operational data from the offshore process, subsea and vent systems to a cloud solution. The presented data is accessed and processed through analytics prior to live presentation on a digital platform accessible to offshore and onshore subsea engineers, and to anyone inside or outside the operator's organization in need for the data and operational status. The aim is to use all available sensor data related to five operative high temperature flexible risers to reveal emerging evolvement of a failure mode previously experienced on similar risers in similar service. Carcass collapse in the seabed segment of the flexible riser is identified as the key failure mode in need for mitigation actions. The collapse is caused by excessive pressure in pipe designs with multi-layer pressure sheath, and has been observed on several occasions during startup after longer maintenance and shut down periods. As the flow rate in the risers is moderate and the performance of wells varies, it is not possible to identify the carcass collapse by pressure drop monitoring, not even with detailed analysis of pressure differences topside and subsea. Concatenating all pressure, temperature, annulus volume testing, inspection and annulus monitoring data in real time established the basis for applying machine learning techniques to identify when a carcass failure emerged. Combining data analytics with in depth understanding of the flexible pipe cross section, failure mode development and pipe dissection experiences enabled an analytics solution providing early warning of an emerging damage. As all the utilized measurement data was available, also for two previous carcass damages in identical risers, validation and confidence of the models could be established to identify these damages early. On this basis, it was concluded that the focused monitoring and digital analytics gave sufficient risk mitigation for the five remaining operating risers of the same type.

Systemic lupus erythematosus (SLE) is characterized by autoantibodies, including antibodies to the nucleosides of DNA. Guanosine is the most immunogenic nucleoside. In this study serum antiguanosine antibody levels were compared with disease activity, determined by their SLEDI score, in 86 patients with SLE. Sera from these patients were tested, by ELISA, for autoantibodies to guanosine, single-stranded DNA (ssDNA), and double-stranded DNA (dsDNA). Anti-doublestranded DNA levels were also measured by RIA. Resultant values from these assays were correlated with SLE disease activity, and compared with specific features of SLE. The strongest correlation was higher levels of antiguanosine antibodies in patients with active lupus nephritis and polyserositis compared to patients with inactive disease (P < 0.0001). Antiguanosine levels also correlated with arthritis (P < 0.006), CNS lupus (P < 0.005), and hematologic manifestations of SLE (P < 0.002). To test the validity of this association in chronic SLE, serum antiguanosine antibodies were measured in patients with SLE at various phases of disease activity. Twelve patients with SLE had serum samples drawn at active, active-improved, and inactive phases over a 3–7 y period. Differences were significant for serum antiguanosine antibodies in the active group compared to the inactive group (P < 0.05) and the active vs the active-improved group (P < 0.02), unlike those for dsDNA and ssDNA by ELISA or RIA. Antiguanosine antibodies correlated more closely with disease activity in SLE patients in this longitudinal study than either anti-dsDNA or ssDNA antibodies. Thus, antibodies to guanosine correlated as well or better with disease activity than the other anti-DNA antibodies measured and should be considered to contribute to the pathology of SLE, especially lupus nephritis.

SUMMARY Using a flow cytometrie method, CD4+, CD8+, αβ TCR+ and TCR variable region gene product (TVRGP)-specific T cells were analysed in heallhy heterosexual males (HHeM). HIV-seronegative homosexual males (SNHM). asymptomatic seropositive homosexual males (ASPH) and homosexual males with AIDS who were either well (AIDS-A). or unwell in hospilal (AIDS-B). Total CD4+ and CD8+ T cell numbers were similar in HHeM and SNHM. CD4+ T cells were significantly reduced in ASPH relative to both HHeM and SNHM and in AIDS-A and AIDS-B relative to SNHM. TVRGP-specific T cells expressed as a percentage of TCR αβ+ cells showed no significant difference in HHeM. SNHM and AIDS-B. The proportion of αβ+ cells expressing the Vβ5·1, Vβ12 and Vα2 gene product (GP) was. however, significantly reduced in ASPH and AIDS-B relative to HHeM. SNHM and AIDS-A. Possible causes of TVRGP-specific T cell deletion arc discussed.

The objective of this study was to determine whether an association could be demonstrated between survival and the expression of the adhesion molecule E-cadherin by the neoplastic cells in a group of dogs with anal sac gland carcinomas (ASGCs). Archived formalin-fixed, paraffin wax-embedded primary tumour specimens were obtained for 36 cases of canine ASGC with known clinical management and survival data. Immunohistochemical methods were used to evaluate E-cadherin expression by the neoplastic cells and data were evaluated for an association between E-cadherin expression and survival. On univariate analysis, the median survival time for cases with tumours expressing E-cadherin in more than 75% of cells was significantly greater than that for cases with tumours expressing E-cadherin in fewer than 75% of cells (1168 versus 448 days, P = 0.0246). Both E-cadherin expression and presence or absence of distant metastases were significantly associated with survival on multivariate analysis. This study demonstrates that expression of E-cadherin at the cytoplasmic membrane in canine ASGCs is variable and potentially predictive of survival.

The Loma Linda University (LLU) Radiobiology Program coordinates basic research and proton beam service activities for the university and extramural communities. The current focus of the program is on the biological and physical properties of protons and the operation of radiobiology facilities for NASA-sponsored projects. The current accelerator, supporting facilities and operations are described along with a brief review of extramural research projects supported by the program. These include space craft electronic parts and shielding testing as well as tumorigenesis and animal behavior experiments. An overview of research projects currently underway at LLU is also described. These include: 1) acute responses of the C57Bl/6 mouse immune system, 2) modulation of gene expression in the nematode C. elegans and rat thyroid cells, 3) quantitation of dose tolerance in rat CNS microvasculature, 4) behavioral screening of whole body proton and iron ion-irradiated C57Bl/6 mice, and 5) investigation of the role of cell integration into epithelial structures on responses to radiation.

Coronary catheterization laboratories (CCLs) are the cornerstones of the delivery system for many cardiovascular procedures performed in the United States. However, few comprehensive data exist benchmarking physician activities in CCLs. This study benchmarks cost and time data on 82,548 consecutive patient encounters in 53 CCLs for the 18-month period of January 1997 through June 1998. The data are compiled from the OEP program, a relational database developed by Boston Scientific/Scimed (Maple Grove, Minnesota) for use in CCLs. CCL productivity (total time and procedure time) and cost (variable costs and device costs) benchmarks are created for: 1) left heart catheterization; 2) right and left heart catheterization; 3) percutaneous transluminal coronary balloon angioplasty (PTCA); 4) atherectomy; and 5) coronary stents. Results show the variable costs (those costs that vary in direct proportion to changes in CCL activities) for the five procedures are: $308, left heart catheterization; $395, right and left heart catheterization; $841, PTCA; $2,768, atherectomy; and $3,186, coronary stent. These variable costs are lower than the typical average costs reported for these procedures because they do not include hospital, laboratory, and physician costs, only the procedure-specific activity-related costs most directly controlled and/or influenced by CCL physicians or administrators. The total time for the left heart catheterization averaged 64 minutes and 84 minutes for the right and left heart catheterization, respectively, and procedural times averaged 25 and 32 minutes, respectively. For the major interventional procedures N PTCA, atherectomy, and coronary stents, total times averages were 102, 135, and 117 minutes, respectively. Procedural times for these procedures averaged between 60 and 65 percent of the total time. The major implications of these findings are discussed and limitations noted.

The in vitro intracellular daunorubicin accumulation (IDA) of blast cells from 69 patients with newly diagnosed acute myeloid leukaemia (AML) was correlated with the expression and functional activity of the multidrug resistance (MDR) proteins, P-glycoprotein (Pgp), multidrug resistance-associated protein (MRP) and lung-resistance protein (LRP). An inverse and significant association was found between IDA and Pgp-related efflux activity (r = -0.31, P = 0.01) and also MRP (r = -0.25, P = 0.04) but not with LRP (r = -0.13, P = 0.28). Coexpression of the MDR proteins had an additive effect in further lowering of IDA levels, suggesting that the clinical MDR phenotype is dependent on the sum of multiple MDR factors available to the leukaemic cell. Thus, the median IDA of leukaemic cells without any MDR proteins was significantly higher than that of blasts carrying two MDR proteins (0.466 vs. 0.296, P = 0.046). Seven patients with no expression of Pgp, MRP and LRP still had low IDA levels, suggesting the presence of efflux MDR mechanisms other than those studied. The relation of IDA to clinical parameters known to be associated with poor prognosis, such as age, secondary AML, karyotype, peripheral blood blast and CD34 counts, was also studied, but no significance was found on multifactorial analysis. There was a non-significant trend for earlier relapse in patients with low IDA levels (leukaemia-free survival of 16.3 months compared with 21.1 months in patients with high IDA levels). Our data suggest that, while the IDA assay is a quick and relatively easy test for the combined efflux MDR phenotype, it is unable to detect other MDR mechanisms, such as LRP, which may be important to the clinical outcome of patients with AML.

SUMMARYT cell antigen specificity is determined by the products of the genes which encode the variable regions of their receptors. Of the T cell receptor (TCR) variable region gene products examined, only Vβ6.7a TCR-positive lymphocytes were reduced in primary Sjogren’s syndrome patients with IgG 1 hypergammaglobulinaemia compared with an age-, sex- and HLA-matched control population. The levels of Vβ6.7a T cells were also significantly reduced when these patients were compared with an age- and sex-matched but HLA-unmatched control group and non-tissue typed normal people of both sexes. Since published studies show no such abnormality in rheumatoid arthritis, systemic lupus erythematosus or other autoimmune diseases, this abnormality may reflect a pathogenic process specific to primary Sjogren’s syndrome.

To evaluate the risk of childhood leukemia in relation to residential electric and magnetic field (EMF) exposures.A case control study based on 88 cases and 133 controls used different assessment methods to determine EMF exposure in the child's current residence. Cases comprised incident leukemias diagnosed at 0-14 years of age between 1985-1993 from a larger study in southern Ontario; population controls were individually matched to the cases by age and sex. Exposure was measured by a personal monitoring device worn by the child during usual activities at home, by point-in-time measurements in three rooms and according to wire code assigned to the child's residence.An association between magnetic field exposures as measured with the personal monitor and increased risk of leukemia was observed. The risk was more pronounced for those children diagnosed at less than 6 years of age and those with acute lymphoblastic leukemia. Risk estimates associated with magnetic fields tended to increase after adjusting for power consumption and potential confounders with significant odds ratios (OR) (OR: 4.5, 95% confidence interval (CI): 1.3-15.9) observed for exposuresor = 0.14 microTesla (microT). For the most part point-in-time measurements of magnetic fields were associated with non-significant elevations in risk which were generally compatible with previous research. Residential proximity to power lines having a high current configuration was not associated with increased risk of leukemia. Exposures to electric fields as measured by personal monitoring were associated with a decreased leukemia risk.The findings relating to magnetic field exposures directly measured by personal monitoring support an association with the risk of childhood leukemia. As exposure assessment is refined, the possible role of magnetic fields in the etiology of childhood leukemia becomes more evident.

A population-based case-control study was conducted in Ontario, Canada, to assess the relation between the risk of childhood leukemia and residential exposure to magnetic fields. Participating subjects consisted of 201 cases, diagnosed at 0 to 14 years of age during 1985-1993, ascertained from the records at the Hospital for Sick Children (Toronto), and 406 individually matched controls. Where possible, point-in-time measurements of magnetic fields were made in all residences occupied by subjects during the period of inquiry in the defined catchment area. Three different classification schemes of wire code were assigned to each residence. Detailed information was collected by interviewer-administered questionnaires, which enabled risk estimates to be adjusted for socio-economic characteristics, medical history of parent(s) and child and environmental exposures. Inconsistent elevations in risk were associated with time-weighted averages of magnetic fields both inside and outside the home for subjects having residential point-in-time measurements that represented at least 70% of their etiological period. These risks increased in magnitude when analysis was restricted to children under 6 years of age at diagnosis or to those with acute lymphoblastic leukemia. For children younger than 6 years at diagnosis, outside perimeter measurements of the residence,or = 0.15 microT, were associated with increased leukemia risk (OR = 3.45, 95% CI = 1.14-10.45). Evaluation of different exposure times for point-in-time magnetic field measurements and wire configuration suggested that exposures earliest in the etiological period were associated with greater risks for children diagnosed at a younger age (OR = 2.50, 95% CI = 1.14-5.49). Our findings did not support an association between leukemia and proximity to power lines with high current configuration.

We investigated the role of the drug resistance-related proteins LRP, MRP and Pgp and the apoptotic suppressor, bcl-2, in relation to other clinical characteristics, with respect to response and survival in 91 patients with newly diagnosed AML, treated with standard chemotherapy. Multivariate analysis showed that poor response to chemotherapy was associated with increasing age (P=0.0004), LRP expression (P=0.0001) and Pgp function (P=0.015). The significant predictors of both leukaemia-free survival (LFS) and overall survival (OS) were LRP (LFS, P=0.01; OS, P=0.0001), Pgp function (LFS, P=0.0001; OS, P=0.0003) and cytogenetic abnormalities (LFS, P=0.0001; OS. P=0.0005). Patients with the lowest expression of LRP and Pgp function and favourable karyotype (group I) had an LFS of 30.2 months compared to 8 5 months in the group with the highest expression of LRP and Pgp and poor prognosis karyotype (group III, P=0.002). OS decreased from 75.4 months in group I to 7.9 months in group III patients (P0.0001). Neither MRP nor bcl-2 were significantly associated with chemotherapy response and survival. Correlations were found between increasing expression of LRP and older age (P=0.05) and an unfavourable karyotype (P=0.005), but these variables were independent of each other in analysis of treatment response and patient survival. Our findings suggest that both LRP and Pgp are clinically relevant drug-resistance proteins and it may be necessary to modulate both LRP and Pgp functions in order to reverse the multidrug resistance phenotype in AML.

OBJECTIVES: To evaluate the risk of having a child with a congenital anomaly in relation to occupational exposure to low level ionising radiation in the pre-conception period. METHODS: A case-control study based on the Canadian congenital anomalies registry used record linkage techniques to identify congenital anomalies among male and female workers in Canada9s largest electric company. Cases were defined as parents of a child with a congenital anomaly born between April 1979 and December 1986 who had a congenital anomaly diagnosed within the first year of life. Controls were an individually matched sample of parents of a liveborn child without an anomaly. Risk of congenital anomaly was assessed in relation to parental exposure to ionising radiation acquired through work within a nuclear generating station of an electric power company. Exposure was assessed according to employment, whether or not the worker was monitored for radiation exposure, and quantitative estimates of radiation dose. RESULTS: Employment within the electric power industry was not associated with an increased risk of congenital anomalies in the offspring of mothers or fathers. Risk estimates for workers monitored (those who are likely to be exposed to ionising radiation) were 1.75 (95% confidence interval (95% CI) 0.86 to 3.55) for mothers and 0.84 (95% CI 0.68 to 1.05) for fathers. Exposure for fathers before conception, defined cumulatively and for six months before conception, was not associated with increased risk of anomalies in their offspring. There were no significant increases in risk found between type of anomaly and any measure of exposure, although the statistical power in these groups was limited. The study had insufficient numbers to evaluate the effects of ionising radiation in mothers as only three mothers had recorded doses > 0 mSv. CONCLUSIONS: Overall, workers in a nuclear power industry, and specifically those exposed before conception to low levels of ionising radiation, do not appear to be at an increased risk of having a liveborn child with a congenital anomaly.

Introduction: Inverse associations have been shown between E-cadherin expression and degree of differentiation in canine mammary tumours and with the acquisition of malignancy in human epithelial cancers. The purpose of this study was to examine whether there was an association between prognosis, and the distribution or intensity of immunohistochemical staining for E-cadherin in anal sac adenocarcinoma. Methods: Formalin-fixed paraffin-wax embedded canine anal sac adenocarcinoma specimens were obtained for 36 patients for whom clinical data, including survival statistics, were available. Canine mammary adenoma tissue was employed as the positive and negative controls with antibody diluent replacing the primary antibody in the latter. Samples were scored according to proportion of cells showing positive cytoplasmic membranous staining, intensity of cytoplasmic membranous staining and proportion of nuclei staining. As quality control, a sample of 10 slides was randomly selected for repeat evaluation; results exactly matched those obtained in the first assessment. Results: All anal sac adenocarcinoma cells expressed E-cadherin to varying degrees. There was no evidence of an association between survival time and the intensity of staining or the proportion of nuclei staining. Patients whose tumours exhibited >75% positive cytoplasmic membranous staining survived significantly longer than those exhibiting

We have recently described a spontaneous murine model of autoimmune thyroid disease. The disorder was in part characterized by reduced thyroid epithelial cell-cell communication that was associated with abnormalities in three major connexins. To compare whether this finding was a common secondary occurrence in autoimmune thyroid disease, or unique to the spontaneous development in the MRL mice, we induced thyroiditis in Lewis rats. Immunization with thyroid extract and thyroglobulin resulted in extensive lymphocytic infiltration and increased expression of major histocompatibility gene complex (MHC) class II surface antigen in the diseased thyroid. Both experimental and control rat thyroid tissues produced gap junction proteins connexin 43, connexin 32, and connexin 26. The connexins in nondiseased tissue was located in the plasma membrane at points of cell-cell contact and labeled as discrete arrays of punctate fluorescence. The quantity of all three connexins were reduced in the diseased thyroid tissue. More importantly, the connexin proteins were not distributed as gap junctions at contacting cell interfaces. Both nondiseased and diseased thyroid tissue expressed messenger RNA (mRNA) for the three connexins, but the diseased tissue had reduced levels of mRNA for connexin 43 (45%), and to a lesser extent, connexin 26 (25%) and connexin 32 (20%). The reduced connexin mRNA, protein, and lack of assembled gap junctions measured in the diseased tissue were obtained under conditions where the infiltrating cells and their potent cytokine products were continuously present. To determine if this difference persisted when these inflammatory components were absent, primary cultures of thyroid cells from control and experimental rats were established and connexin localization experiments repeated. The diseased thyroid cells, like the diseased tissue, lacked plasma membrane associated connexin protein. The lack of gap junction assembly in the thyrocytes cultured from the diseased tissue was accompanied by a loss of functional coupling. Collectively, the data document that autoimmune diseased thyroid tissue from both the spontaneous mouse and induced rat models have reduced plasma membrane assembled gap junctions and deficient intercellular communication as determined by the inability to transfer lucifer yellow dye to contiguous cells. Nondiseased cultured thyrocyte monolayers and follicles transferred dye to second and third order neighboring cells in 80 and 95% of trials, respectively. In contrast, only 5-10% of the diseased thyrocytes transferred microinjected dye, and in these cases the transit was limited to primary contacting cells. Culturing removed inequities introduced by the infiltrating cells and their products. However, the established cultures of diseased thyroid cells retained their communication deficiency. This suggests that the loss of communication may be a common abnormality in autoimmune disease, and furthermore, this uncoupling could contribute to the loss of coordinated hormonal regulation (hypothyroidism) in the diseased thyroid gland in the absence of thyroid cell destruction.

MRL-lpr/lpr mice manifest a systemic lupus-like autoimmune disease. As part of this syndrome, the mice spontaneously develop autoimmune thyroiditis, which is morphologically and biochemically similar to human autoimmune thyroiditis. In this study we investigated whether thyroid tissue obtained from sites of chronic inflammation had altered gap junctional communication. Fresh tissue sections revealed that thyroid from the nondiseased mice (MRL-(+)/+) had connexins (Cx) localized to the plasma membrane at points of thyroid cell-cell contact. In contrast, the Cx in diseased mouse (MRL-lpr/lpr) thyroid tissue were not localized to the plasma membrane, and the fluorescent intensity was reduced for Cx43 and Cx26. Northern analysis confirmed that murine thyroid tissue expressed messenger RNA for these Cx. However, the diseased tissue expressed lower levels of Cx32 and Cx26 messenger RNA. The infiltrating cells and their biologically active products present in the diseased thyroid tissue may mediate the reduced Cx expression and aberrant gap junctional assembly. We established primary thyrocyte cultures to determine whether these differences persisted when the inflammatory factors were removed. The nondiseased thyroid cells were communication competent, with fluorescent dye transfer proceeding from the injected cell to primary contacts (95%) and to second and third order neighboring cells in 75% of the trials. Thyroid cells from the diseased mice were communication incompetent, in that 80% of microinjections failed to result in dye transfer to cells in direct contact. Immunocytochemistry indicated that the functional coupling in the normal mouse thyroid cells was associated with Cx43 located in the plasma membrane as assembled gap junctional plaques. The communication-deficient diseased thyroid cells had internalized Cx43 predominantly localized to perinuclear regions of the cells. Collectively, these data document altered Cx-protein distribution in the autoimmune diseased thyroid. The diseased thyroid tissue was devoid of plasma membrane identifiable gap junctions and deficient in intercellular communication. Culturing removed the inflammatory mediators; however, the disease cells retained their communication incompetence. These results suggest that if this deficiency was initiated by components of the inflammation process, then protracted changes must have occurred so that the continued presence of these factors was no longer required to sustain this difference.

SUMMARY Serum levels of the soluble form of the low-affinity receptor for IgE (FcERII, CD23) (sCD23) are elevated in autoimmune conditions associated with hypergammaglobulinaemia and B cell hyperactivity. Very high levels of sCD23 are found in patients with B-chronic lymphatic leukaemia (B-CLL) who are, however, frequently hypogammaglobulinaemic. We therefore compared the serum levels of sCD23 in healthy controls (n= 33) with three conditions associated with hypogammaglobulinaemia (HGG) and varying B cell numbers: X-linked agammaglobulinaemia (XLA, n= 12), common variable immunodeficiency (CVI, n= 20) and B-chronic lymphatic leukaemia (n= 33). Serum levels of sCD23 showed a significant correlation with the CD19+ B cell count in both normals and patients with CVI (r= 0 65, P < 0·0001). Amongst the different clinical groups, serum levels of sCD23 were increased in the order XLA < CVI < normals < CLL (medians 2·5, 7·7, 11·1 and 540, respectively; P < 0·001 for all comparisons except CVI versus normals P < 0·03 in a one-tailed test). In the CVI group, serum sCD23 was lowest amongst four patients with low B cell numbers. There was no overlap in sCD23 between patients with XLA and this subgroup of CVI patients. Serum sCD23 is, therefore, derived predominantly from B cells, and is significantly related to the peripheral blood B cell count.

Ethers of cis or trans D-4-hydroxyproline (Hype), adjacent to octahydroindole-carboxylic acid (Oic), introduce a beta-turn into the backbone of peptides when positioned respectively at the i+1 and i+2 position of the turn. This is confirmed by NMR experiments performed on a model tetrapeptide in water. Synthetic alteration of the ether group allows simple probing of the steric limits and electrostatic potential of a receptor binding site, a technique applied successfully to the bradykinin receptor.

A cohort mortality study was undertaken of forestry workers at a public electrical utility who had worked for six months or more during 1950-82 and who were routinely exposed to herbicides including phenoxy acids. A total of 1222 men with 25 274 years at risk experienced 80 deaths. Ascertainment of vital state at the end of follow up was 95.5%. The male population of the province (Ontario) was used as the reference group. Overall, no excess mortality was found in this cohort relative to the reference population. A statistically significant increase in deaths occurred, however, due to suicide (SMR = 210, 95% confidence interval, 95% CI 105-376) for the cohort as a whole. No deaths were seen due to cancers such as soft tissue sarcoma and non-Hodgkin's lymphoma that have been cited by other authors as being associated with exposure to phenoxy acid herbicides. Although the cohort is not large, the absence of deaths due to these cancers is consistent with findings from other studies with sufficient numbers to allow examination of specific risks. The cohort is still young, however, and at the end of follow up most had not reached an age when increased incidence of cancer would normally be expected.

Purpose The expression of CD40 ligand (CD40L) in individuals with systemic lupus erythematosus (SLE) is prolonged when compared to expression on normal T cells. A defect in the down-regulation of the Ras, an intracellular G-protein involved in cell proliferation and differentiation, has been implicated in abnormally prolonged expression of CD 40L on lupus T cells. Inactivation of Ras with farnesylthiosalicylic acid (FTS) in lupus T cells leads to a temporary down-regulation of CD40L expression. SLE is characterized by antinuclear antibodies directed against DNA as well as to individual nucleosides. Guanosine has been demonstrated to be the most immunogenic nucleoside. Serum antiguanosine antibody levels correspond well with disease activity in patients with SLE. Antiguanosine antibodies in murine and human lupus have been shown to have the internal image of the G-binding protein Ras. In this study we investigated whether the murine antiguanosine antibody (4H2) was internalized in living cells and whether it modulated Ras mediated T lymphocytes signal transduction and CD40L expression in normal individuals. This is a continuation of a study that was previously undertaken to look at CD40L expression and the involvement of Ras. Methods Antiguanosine antibody was isolated from murine hybridoma supernatant and quantified by Bradford Assay. Freshly isolated lymphocytes from healthy controls and SLE patients were obtained with histopaque. Cells were then divided into plus/minus treatment with 4H2 and FTS. The lymphocytes were incubated, fixed, and labeled with anti-CD40L. Results Our previous studies showed that the expression of CD40L in lupus patients was modulated when Ras was inhibited by FTS treatment but this did not occur in the healthy group. Conclusion In previous studies, Ras was implicated in the sustained elevation of CD40L on lymphocytes from patients with SLE. In this continuation study 4H2 antiguanosine antibody was used to determine if the Ras-mimicking potential of this internalizing antibody was capable of modulating CD40L levels on healthy lymphocytes. The results thus far show that the addition of FTS did not alter the levels of CD40L on healthy lymphocytes. Whether the 4H2 antiguanosine antibody elevated the levels of CD40L was inconclusive. Currently studies are under way to expand the concentrations of 4H2 tested and to vary the times of incubation.

A host of immunologic abnormalities have been thoroughly described in systemic lupus erythematosus. There is an increasing body of evidence that the production of autoantibodies is the result of abnormal regulation of T cells of the early monitored response to autoantigens. Available data in the literature suggest there is a possible defect in the down-regulation of the Ras pathway in lupus T cells leading to a failure to develop anergy and abnormally prolonged expression of CD40 ligand. Treatment of MRL/lpr mice with the Ras inhibitor S-farnesylthiosalicylic acid (FTS) reduced disease symptoms in the treated mice, indicating that modulation of Ras may represent a novel therapeutic approach in SLE. In this study we are investigating the expression of CD40 ligand in CD40+ T cells from lupus and healthy subjects before and after inactivation of Ras by FTS, a synthetic substance that detaches Ras from the inner cell membrane and induces its rapid degradation. The results of our study will help us understand if the defective functioning of Ras in lupus T cell is an intrinsic defect (by comparing the results with the ones from healthy subjects) versus an acquired one, possibly through autoantibodies. This is a continuation of a study that was previously undertaken to look at CD40 ligand expression. Methods Freshly isolated lymphocytes from SLE and healthy controls were established in culture and a portion treated with FTS and treated and untreated samples were harvested by fixation at 3 and 6 hours post initiation of treatment (FTS). The fixed lymphocytes were immunolabeled for CD40L, and dual labeled with CD3 and CD20. The secondary fluorescence was quantified by laser scanning cytometry. Results The initial study revealed that the expression of CD40L in lupus patients was modulated when Ras was inhibited by FTS treatment. The down-regulation of CD40L in SLE by FTS treatment occurred at the 4 hour harvest but was refractory at the 48 hour time point. The healthy controls showed no modulation of CD40L expression with or without FTS treatment. The current study used 3 and 6 hours ± FTS treatment and found that at 3 hours post treatment the SLE lymphocytes had down-regulated CD40L but the controls did not. At the 6 hour time point the SLE patient CD40L levels were increasing, whereas the control levels did not change. Conclusions Ras inactivation by FTS was able to markedly decrease the level of CD40L in lupus T cells but did not appear to modulate the level of CD40L in healthy subjects.

Gallosilicate molecular sieves with an MFI structure are very promising catalysts for upgrading light olefins and paraffins to aromatics. Gallosilicate catalysts are quite stable at low reaction temperature, however, when subjected to high temperature, gallosilicate catalysts deactivate rapidly. The activity and selectivity of these catalysts are greatly influenced by both framework and non-framework gallium. Although the framework gallium imparts acidity to the sieve, the nature of the non-framework gallium is unclear. In the present study, combined techniques of analytical electron microscopy (AEM), high resolution transmission electron microscopy (HREM) and X-ray diffraction (XRD) have been applied to study the fate of framework and non-framework gallium in progressively deactivated gallosilicate molecular sieve catalysts. To study this progressive process, fresh gallosilicate molecular sieve and the gallosilicate catalysts (with 40% Cab-O-Sil matrix) subjected to steaming treatments at different temperatures and durations were characterized.The microstructure of fresh gallosilicate catalysts consists of highly crystalline molecular sieve which is uniformly distributed in the amorphous supporting matrix (Fig. 1).

We have cloned lines of IL 2-dependent human T cells derived from alloantigen, soluble antigen (tetanus toxoid), mitogen, or IL 2-stimulated peripheral blood lymphocytes and characterized their surface marker expression and cytolytic activity. The surface phenotype and cytolytic function was compared with the ability of these T cell clones to release cytotoxic lymphokines in response to mitogenic lectins. The cytotoxins released by these CTL clones were detected on the murine L929 target cells in a 16-hr assay. All of the T cell clones, whether stimulated by HLA alloantigens, tetanus toxoid, or mitogens, exhibited killer cell activity and the capacity to secrete a soluble cytotoxin(s). Specific polyclonal antisera to recombinant human tumor necrosis factor (rTNF) and human alpha-lymphotoxin (alpha LT) were unable to neutralize the cytotoxic activity released by most of these CTL clones. These results indicate that human CTL produce a novel antigenic form(s) of cytotoxin that we have termed CTL-toxin. Supernatants from several CTL clones yielded a cytotoxic activity that was partially neutralized (10 to 40%) by saturating levels of anti-TNF (but not anti-alpha LT) indicating that human CTL may be capable of producing a TNF-like molecule. Only two out of 60 CTL clones studied thus far produced a cytotoxic activity that was partially neutralized by anti-alpha LT (20 to 40%). Collectively, these results suggest that although both the CD4 and the CD8 subpopulations of human cytotoxic T cells may be capable of releasing several types of cytotoxins in response to mitogenic signals, the predominant cytotoxin is distinct from alpha LT and TNF.

Several cloned lines of IL 2-dependent human T cells derived from alloantigen, mitogen, or IL 2-stimulated peripheral blood lymphocytes were examined for their surface marker expression, cytolytic activity in a 51Cr-release assay, and capacity to release cytotoxic lymphokines. Thirty cell lines exhibiting either antigen-specific natural killer cell activity or lectin-dependent killer cell function, which expressed either the CD4 or CD8 surface differentiation markers, were capable of producing cytotoxin(s) in response to the lectins phytohemagglutinin and concanavalin A. Cytotoxin activity was detected on the murine L929 target cell in a 16-hr cytotoxicity assay. In contrast, several nonlytic T cell tumor lines failed to produce a soluble cytotoxin. Antibodies capable of neutralizing human alpha-lymphotoxin were completely ineffective in inhibiting the cytotoxin(s) produced by any of the cytotoxic T lymphocytes (CTL) cell lines. Comparative gel filtration and HPLC hydrophobic chromatography of alpha-lymphotoxin and CTL toxin produced by the CTL-830.B2 clone revealed significant differences in their elution profiles. The CTL-produced toxin and alpha-lymphotoxin exhibited similar kinetics of lysis of the L929 target cells, with 50% target cell lysis occurring at 10 hr. These data indicate human CTL produce a cytotoxin(s) antigenically distinct from alpha-lymphotoxin and imply that human cytolytic effector T cells are not the cellular source for the production of human alpha-lymphotoxin. The relationship of alpha-lymphotoxin and CTL toxin production was investigated in unseparated peripheral blood mononuclear cells stimulated with lectins or IL 2 for 1 and 5 days. Anti-alpha-lymphotoxin antibodies were capable of neutralizing only 30 to 50% of the cytotoxic activity in 24-hr supernatants. Cytotoxic activity in supernatants harvested after 120 hr stimulation with PHA or Con A was neutralized 70 to 100%, whereas the toxin(s) released from IL 2-stimulated lymphocytes was only neutralized 30%. These data suggest the observed heterogeneity of cytotoxic lymphokines produced by unseparated mononuclear cells depends in part on the subpopulations of effector cells responding to a given stimulus and the capacity of different subpopulations to produce distinct cytotoxins.

An analysis of the relationship between TNF receptor occupancy and the kinetics of cell death has been conducted in the sensitive L929.10 murine fibrosarcoma cell line. The receptor affinity and number, measured by competitive and saturation binding assays with human 125I-TNF, is consistent with a single class of binding sites having a Kd = 1.5 nM and 7,000 sites/cell. Human lymphotoxin competed equally well with TNF for binding to the receptor. Determination of the kinetics of L929.10 cell death as a function of TNF concentration revealed three sequential phases to the cytolytic process: An induction phase, that lasted 4 to 9 hrs after the addition of TNF, in which no cell death occurred; the burst phase in which cells died at a rate of 12 to 14% per hr; and the third phase, termed the slow lytic phase, was characterized by a rate of lysis of 1 to 2% per hr. Two parameters, the length of the induction phase and the percentage of cells killed in the burst phase, were dependent on TNF receptor occupancy. Both of these receptor dependent processes were maximized at 10% receptor occupancy. Half maximal lysis of the L929.10 clone was achieved at 10 pM or 0.67% receptor occupancy. In contrast, the rates of cell death during the burst phase and the slow lytic phase were independent of the concentration of TNF. Mitomycin C, an antitumor drug that alkylates and crosslinks DNA, enhanced the sensitivity of the L929.10 cells to TNF mediated lysis by modulating both of the TNF receptor dependent processes and by doubling the (apparent) rate of cell death (22 to 25%/hr) during the burst phase. These results suggest a direct relationship exists between the strength of the TNF-receptor signal and nuclear events, perhaps those associated with processes involved in DNA replication or cell division, during the cytotoxic reaction induced by these inflammatory cytokines.

Human T cell hybrids were constructed between lectin-activated peripheral blood lymphocytes and CEM.TET1, a variant of the CEM T lymphoblastoid cell line. Hybrids were screened for their ability to produce cytotoxic lymphokines and interleukin-2 (IL-2) following lectin activation. Five hybrids were identified that released significant levels (greater than 75 units/ml) of cytotoxic activity that was detected on the murine L929 target cells; three hybrids were identified that produced IL-2. Cell surface phenotype of the T cell hybrids did not correlate with their ability to produce these lymphokines. The II-23 hybrid (CD3+;4+) produced an inducible cytotoxic activity that was fully neutralized by anti-lymphotoxin antibodies. The release of lymphotoxin (LT) rapidly attained maximum levels 12 hrs to 24 hrs after lectin activation; IL-2 production was maximum at 48 hrs. The induction of LT and IL-2 release required similar membrane stimulating agents. The phorbol ester, phorbol 12-myristate 13-acetate (PMA) in combination with phytohemagglutinin or concanavalin A, were required for maximal release of LT and IL-2. Anti-CD3 monoclonal antibodies coupled to agarose, but not anti-T200-agarose, induced the release of high levels of LT and IL-2. Soluble anti-CD3 was not sufficient to induce IL-2 or LT release from the II-23 hybrid; however, soluble anti-CD3 combined with PMA was a strong stimulus for lymphotoxin and IL-2 release. The II-23 hybrid also functioned as a cytotoxic T cell line in a 51Chromium release assay. Induction of killer cell function required similar perturbation of Ti/CD3 complex. This human T cell hybrid line offers an inducible model system for the simultaneous study of the molecular events regulating the production of growth inhibitory/cytotoxic (LT) and growth promoting (IL-2) lymphokines and cytotoxic T cell function.