Effect of inflammatory cytokines on hypoxia-induced erythropoietin production.

The effects of the inflammatory cytokines interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-6, transforming growth factor-beta (TGF-beta), and tumor necrosis factor-alpha (TNF-alpha) on erythropoietin (Epo) production in Hep3B cells were examined. The addition of IL-1 alpha, IL-1 beta, or TNF-alpha resulted in a dose-dependent inhibition of hypoxia-induced Epo production by as much as 89%. IL-1 beta was the most effective cytokine tested, demonstrating half-maximal inhibition at 0.4 U/mL compared with 1.0 and 10.0 U/mL for IL-1 alpha and TNF-alpha, respectively. TGF-beta also inhibited hypoxia-induced Epo production, but only by as much as 56%. In contrast to IL-1 alpha, IL-1 beta, TNF-alpha, and TGF-beta, the addition of IL-6 to hypoxic Hep3B cells resulted in a dose-dependent stimulation of hypoxia-induced Epo production by as much as 81%. However, IL-6 did not stimulate Epo synthesis in the absence of hypoxia, and was thus synergistic with hypoxia in inducing Epo production. Combinations of IL-1 alpha, TNF-alpha, and IL-6 were found to be additive in their effects on hypoxia-induced Epo production. By Northern blot analysis, Epo messenger RNA levels in Hep3B cells grown in 1% O2 were decreased when concurrently exposed to either IL-1 alpha or TNF-alpha. The effects that IL-1 alpha, IL-1 beta, TGF-beta, TNF-alpha, and IL-6 have on hypoxia-induced Epo production may provide new insights into the signal transduction pathway by which hypoxia leads to changes in gene expression. In addition, the effects of these inflammatory cytokines on hypoxia-induced Epo production in vitro suggest that in various inflammatory disorders these cytokines may affect Epo production in vivo and may play a significant role in the pathogenesis of the anemia of chronic disease.     

Analysis of human platelet glycoproteins IIb-IIIa and Glanzmann's thrombasthenia in whole blood by flow cytometry

Antibodies that bind to human platelet membrane glycoproteins IIb and IIIa were used to develop methods for analyzing platelet membrane components by flow cytometry. Platelets were tentatively identified by their low-intensity light scatter profiles in whole blood or platelet- rich plasma preparations. Identification of this cell population as platelets was verified by using platelet-specific antibodies and fluorescein-conjugated antiimmunoglobulin. Two-parameter analysis of light scatter versus fluorescence intensity identified greater than 98% of the cells in the "platelet" light scatter profile as platelets due to their acquired fluorescence. Both platelet-rich plasma and whole blood were used to study platelet membrane glycoproteins IIb and IIIa on a single cell basis in an unwashed system. Prostacycline was included in these preparations as a precautionary step to inhibit platelet aggregation during analysis. Flow cytometry is a successful technique for rapid detection of platelet membrane defects such as Glanzmann's thrombasthenia. Platelets from Glanzmann's thrombasthenic individuals were readily distinguished from platelets with normal levels of glycoprotein IIb and IIIa and from platelets with glycoprotein levels characteristic of heterozygote carriers of this disorder. This technique provides a sensitive tool for investigating platelet functional defects due to altered expression or deficiency of platelet surface proteins.     

Heterogeneity of large granular lymphocyte proliferations: delineation of two major subtypes

Two major types of lymphocytosis of large granular lymphocytes (LGLs) were observed. The proliferating LGLs in each type had distinct immunophenotypes, functional characteristics, and probably belonged to different cell lineages. The more common form (Type A) consisted of cells derived from the T cell lineage and had the T suppressor/cytotoxic phenotype (T11+, T3+, T8+). The expression of the Leu 7 and HLA-DR antigen was variable. These cells did not have natural killer (NK) function but showed a variable degree of antibody-dependent cell-mediated cytotoxic (ADCC) activity. Neutropenia was invariably present and rheumatoid arthritis and autoantibodies were frequent associations. These lymphocytes had many similarities to the major type of LGLs present in normal adult bone marrow. The other type of LGL lymphocytosis (Type B) consisted of cells lacking the antigens T3 and T8 but expressing M1 and NKH1. These cells possessed strong NK and ADCC activity but their cell lineage was not clear. Neutropenia and autoimmune phenomena were not detected. The cytochemical characteristics of the LGL granules from both types of patients were similar but differences in ultrastructure were observed. LGLs from Type B patients proliferated in the presence of Interleukin 2 (IL-2) and 12- O-tetradecanoyl-phorbol-13 acetate (TPA). Significant changes in their basic T11+, T3-, T8- phenotype were not observed. IL-2 and TPA, however, had profound influence on the NK function of the cells with enhancement in the case of IL-2 and marked suppression when stimulated by TPA.     

Transforming growth factor-beta 1 cooperates with anti-immunoglobulin for the induction of apoptosis in group I (biopsy-like) Burkitt lymphoma cell lines

Group I Burkitt lymphoma (BL) cell lines, which retain the original biopsy phenotype, have been shown to enter apoptosis in response to a number of external stimuli including serum deprivation, thermal shock, addition of calcium ionophore, and ligation of surface immunoglobulin (Ig) by antibody. Transforming growth factor-beta 1 (TGF beta 1) is known to cause growth arrest in BL lines. Here we show that while it is by itself capable of promoting some degree of apoptosis in group IBL cells, TGF beta 1 cooperates with anti-immunoglobulin to this end. Trimeric soluble recombinant human CD40 ligand (sCD40L) was able to inhibit apoptosis induced by the combination of agonists to some degree, but such rescue proved to be short-lived. Both TGF beta 1 and anti-Ig individually caused BL cells to undergo growth arrest at the G1 phase of cell cycle before their entry into apoptosis: the consequence of sCD40L addition was to maintain the cells in cycle for longer. No induction of the apoptosis-protecting gene, bcl-2, occurred in the presence of sCD40L. These findings are discussed, particularly highlighting the relationship existing between survival and the cell cycle. The strong cooperative effects observed between anti-Ig and TGF beta 1 in promoting apoptosis and the inability of CD40 to signal for long-term rescue raise the potential for a novel therapeutic attack on B-cell lymphoma.     

Occurrence of the t(2;5)(p23;q35) in non-Hodgkin's lymphoma

Primary CD30(Ki-1)-positive anaplastic large-cell lymphoma (ALCL) is considered by some to be a distinct clinicopathologic entity associated with the t(2;5) (p23;q35). However, the specificity of t(2;5) for ALCL has not been carefully studied. Therefore, we performed a detailed analysis of all cases of ALCL with abnormal cytogenetics results in the Nebraska Lymphoma Study Group registry, as well as all other cases of non-Hodgkin's lymphoma with t(2;5) in the registry. We found the t(2;5) in only five of 10 cases of ALCL, four of whom were young patients. However, we also found the t(2;5) in 11 other cases of nonanaplastic lymphoma, including eight children with typical peripheral T-cell lymphomas of various types. The t(2;5) was also found in three older adults with B-cell lymphomas of various types. Thus, the t(2;5) was not specific for CD30+ ALCL. However, t(2;5) may define a clinicopathologic entity in children and young adults characterized by variable morphologies with a T-cell or indeterminate phenotype, CD30-positivity, nodal disease with frequent extranodal involvement, advanced stage, and an excellent response to therapy, including bone marrow transplantation for relapsed disease. The clinical relevance of the t(2;5) in older patients requires further study.     

The contribution of employer characteristics to continued employment of employees with residual work capacity: evidence from register data in The Netherlands

Objectives:This study aimed to examine the contribution of employer characteristics to continued employment of employees with residual work capacity. Moreover, we examined whether the contribution of employer characteristics differs across types of employers and employees’ types of diseases.Methods:Register data on disability assessments and employment status of N=84 394 long-term sick-listed employees with residual work capacity were obtained from the Dutch Employee Insurance Agency between 2010 and 2017. The dependent variable was continued employment four months after the assessment. We linked employees to their (former) employer to measure sector, firm size, and workforce composition. The average employment outcome of all employees assessed in the same firm and year served as a proxy measure for the extent of implemented disability-related policies and practices. Using multilevel multiple regression analysis, we compared the relative contribution of employer characteristics with employees’ characteristics.Results:Employer characteristics accounted for 10% of the variability in employment outcomes. In comparison, employees’ socio-demographic and disease characteristics accounted for 13% of the variability. The prevalence of continued employment was lowest in smaller firms and construction and low-wage service-orientated sectors. Furthermore, there were sizeable differences in employment outcomes between similar employers in terms of size, sector and workforce-composition, particularly between larger firms and among employees with mental or musculoskeletal disorders compared to other diseases.Conclusions:This study shows substantial differences between employers in facilitating continued employment of employees with residual work capacity. Encouraging firms to invest more in disability-related policies and practices may result in better employment opportunities for these employees.     

A prospective study examining balance confidence among individuals with lower limb amputation

Purpose:?In this study we assessed whether balance confidence scores changed over a 2-year follow up period, and identified predictors of balance confidence and predictors of change in balance confidence among lower limb amputees.

Method:?A prospective follow-up survey of 245 community living adults with unilateral below and above knee lower limb amputation who used their prosthetic limb daily was conducted. Balance confidence, assessed using the 16-item Activity-specific Balance Confidence (ABC) Scale, socio-demographic, health and amputation related variables were collected at baseline and 2 years later.

Results:?ABC scores were similar at baseline (mean?= 67.6; SD?=?25.7) and follow up (mean?=?68.0; SD?=?25.8). Lower balance confidence scores at follow up were predicted by older age, being female, use of a mobility device, poor perceived health, increased symptoms of depression, having to concentrate while walking, and fear of falling (all p?<?0.05). Predictors of change in balance confidence included gender and perceived health (all p?<?0.05).

Conclusion:?Balance confidence appears to be a persistent problem in the amputee population. Health professionals are encouraged to consider balance confidence as a potentially important variable that may influence function in this clinically unique group of individuals. The identified predictor variables may be useful to clinicians in targeting individuals who require attention to improve balance confidence.     

INVOLVEMENT OF NON-NMDA AND NMDA RECEPTORS IN GLUTAMATE-INDUCED PRESSOR OR DEPRESSOR RESPONSES OF THE PONS AND MEDULLA

1. Fifty-five intact and six baroreceptor denervated and vagotomized cats of either sex were anaesthetized intraperito-neally with urethane (400 mg/kg) and a-chloralose (40 mg/kg). Responses of the systemic arterial pressure (SAP), mean SAP (MSAP) and sympathetic vertebral nerve (VNA) and renal nerve activities (RNA) were recorded. 2. In intact animals, monosodium L-glutamate (Glu, 0.1 mol/L, 50 nL) was microinjected into pressor areas of the locus coeruleus (LC), gigantocellular tegmental field (GTF), rostral ventrolateral medulla (RVLM) and dorsomedial medulla (DM), and the depressor areas of caudal ventrolateral medulla (CVLM). The induced actions were compared before and after microinjection of either glutamate antagonists, glutamate diethylester (GDEE, 0.5 mol/L, 50–100nL), a competitive AMPA receptor blocker, or 2-amino-5-phosphonovaleric acid (D-AP5, 0.025 mol/L, 50–100 nL), a competitive N-methyl-D-aspartate (NMDA) receptor blocker. GDEE completely blocked the increases of SAP and VNA elicited from all pressor areas. D-AP5 only partially blocked the pressor but slightly blocked VNA and RNA responses from LC, GTF and DM, particularly those from RVLM. Neither GDEE nor D-AP5 blocked the depressor responses of SAP and two nerve activities elicited from CVLM. 3. In baroreceptor denervated animals, NMDA (2 mmol/L, 50–100 nL) and AMPA (0.2 mmol/L, 50–100 nL) were micro-injected into the same pressor areas of GTF, RVLM and DM and the depressor area of CVLM responsive to Glu activation (0.1 mol/L, 30 nL). In RVLM, DM and CVLM, the results of either NMDA or AMPA were similar to those induced by Glu. However, in GTF, microinjection of either NMDA or AMPA did not induce similar responses to Glu. This suggests that the nature of GTF may differ from RVLM and DM. 4. The above results suggest that the Glu-induced pressor responses from LC, GTF, DM and especially RVLM, are primarily mediated through AMPA receptors. The Glu-induced depressor responses from CVLM may not be predominantly mediated by either AMPA or NMDA receptors. 5. In both baroreceptor-intact and -denervated cats stimulation of the pressor areas often produced an increase of VNA and a decrease of RNA, while in the depressor CVLM decreased both VNA and RNA. The VNA, but not RNA were positively correlated with the pressor responses, while both VNA and RNA were positively correlated with the depressor responses. This may suggest that neurons of the sympathetic vertebral and renal nerves are topographically organized in the brain.