Peer victimization, posttraumatic stress symptoms, and chronic pain: A longitudinal examination

Chronic pain and posttraumatic stress disorder symptoms (PTSS) co-occur at high rates in youth and are linked to worse pain outcomes and quality of life. While peer victimization has been posited as a mechanism underlying the PTSS-pain relationship in youth, empirical evidence suggests that it may exacerbate both PTSS and pain. The present study aimed to longitudinally examine PTSS as a mediator in the relationship between peer victimization at baseline and pain-related outcomes at 3 months in youth with chronic pain. Participants included 182 youth aged 10-18 years recruited from a tertiary level children's hospital in Western Canada. At baseline, participants completed measures to assess pain (intensity and interference), peer victimization (relational and overt), and PTSS. Pain was re-assessed at 3-month follow-up. Primary hypotheses were tested utilizing a series of mediation analyses with PTSS as a proposed mediator in the associations between peer victimization and pain outcomes. Youth PTSS mediated the relationship between higher baseline relational victimization and higher 3-month pain interference, while controlling for baseline pain interference. Three-month pain intensity was not correlated with peer victimization; thus, pain intensity was not included in analyses. These findings reveal that PTSS may be an underlying factor in the co-occurrence of peer victimization and chronic pain in youth. Further research is needed to better understand the role of peer victimization in the maintenance of chronic pain to ensure appropriate, effective, and timely interventions that address the social and mental health issues impacting the lives of these youth as well as their pain. PERSPECTIVE: PTSS may be an underlying factor in the co-occurrence between peer victimization and chronic pain in youth, highlighting the need to assess for both peer relationship problems and PTSS in youth with chronic pain.

LPS and LAM activation of the U373 astrocytoma cell line: differential requirement for CD14

CD14 is a membrane protein (mCD14) found on monocytes and neutrophils that is required for the innate immune response to lipopolysaccharide (LPS) and lipoarabinomannan (LAM). CD14 can also be found in serum as soluble CD14 (sCD14) that when bound to bacterial products, enables many non-CD14 bearing cells to be activated. Lipopolysaccharide binding protein (LBP) is a plasma protein that disaggregates and catalytically transfers LPS to CD14. To examine the role of CD14 and LBP in LAM-dependent activation, we used the U373 astrocyte cell line to stably express membrane-bound CD14 (U373-CD14). In serum-free conditions, U373-CD14 cells could respond to LAM stimulation as measured by expression of intracellular adhesion molecule-1 (ICAM-1). Vector control cells (U373-RSV) could not respond to LAM or LPS; but, upon the addition of serum as a source of soluble CD14, control U373-RSV cells could respond to LPS, but not LAM. Therefore, LAM can activate U373 cells only through membrane CD14 and not soluble CD14. We also demonstrate that this membrane CD14-dependent LAM response is greatly facilitated by the addition of LBP.

Membrane-anchored forms of lipopolysaccharide (LPS)-binding protein do not mediate cellular responses to LPS independently of CD14

Inflammatory responses of myeloid cells to LPS are mediated through CD14, a glycosylphosphatidylinositol-anchored receptor that binds LPS. Since CD14 does not traverse the plasma membrane and alternatively anchored forms of CD14 still enable LPS-induced cellular activation, the precise role of CD14 in mediating these responses remains unknown. To address this, we created a transmembrane and a glycosylphosphatidylinositol-anchored form of LPS-binding protein (LBP), a component of serum that binds and transfers LPS to other molecules. Stably transfected Chinese hamster ovary (CHO) fibroblast and U373 astrocytoma cell lines expressing membrane-anchored LBP (mLBP), as well as separate CHO and U373 cell lines expressing membrane CD14 (mCD14), were subsequently generated. Under serum-free conditions, CHO and U373 cells expressing mCD14 responded to as little as 0.1 ng/ml of LPS, as measured by NF-kappaB activation as well as ICAM and IL-6 production. Conversely, the vector control and mLBP-expressing cell lines did not respond under serum-free conditions even in the presence of more than 100 ng/ml of LPS. All the cell lines exhibited responses to less than 1 ng/ml of LPS in the presence of the soluble form of CD14, demonstrating that they are still capable of LPS-induced activation. Taken together, these results demonstrate that mLBP, a protein that brings LPS to the cell surface, does not mediate cellular responses to LPS independently of CD14. These findings suggest that CD14 performs a more specific role in mediating responses to LPS than that of simply bringing LPS to the cell surface.

Isolation of unknown genes from human bone marrow by differential screening and single-pass cDNA sequence determination

A cDNA sequencing project was initiated to characterize gene expression in human bone marrow and develop strategies to isolate novel genes. Forty-eight random DNAs from total human bone marrow were subjected to single-pass DNA sequence analysis to determine a limited complexity of mRNAs expressed in the bone marrow. Overall, 8 cDNAs (17%) showed no similarity to known sequences. Information from DNA sequence analysis was used to develop a differential prescreen to subtract unwanted cDNAs and to enrich for unknown cDNAs. Forty-eight cDNAs that were negative with a complex probe were subject to single-pass DNA sequence determination. Of these prescreened cDNAs, the number of unknown sequences increased to 23 (48%). Unknown cDNAs were also characterized by RNA expression analysis using 25 different human leukemic cell lines. Of 13 unknown cDNAs tested, 10 were expressed in all cell types tested and 3 revealed a hematopoietic lineage-restricted expression pattern. Interestingly, while a total of only 96 bone marrow cDNAs were sequenced, 31 of these cDNAs represent sequences from unknown genes and 12 showed significant similarities to sequences in the data bases. One cDNA revealed a significant similarity to a serine/threonine-protein kinase at the amino acid level (56% identity for 123 amino acids) and may represent a previously unknown kinase. Differential screening techniques coupled with single-pass cDNA sequence analysis may prove to be a powerful and simple technique to examine developmental gene expression.

A new approach to understanding T cell development: the isolation and characterization of immature CD4-, CD8-, CD3- T cell cDNAs by subtraction cloning

During T cell development in the mammalian thymus, immature T cells are observed that lack the cell surface markers CD4, CD8, and CD3. A subtracted cDNA library was constructed to isolate cDNAs that are specific for these immature T cells. Tissue-specific expression of 97 individual cDNAs were examined using different cell types by Northern blot analysis, and six cDNAs were analyzed by reverse transcriptase (RT) polymerase chain reaction (PCR) detection of RNA. Approximately 50% of the clones could not be detected on Northern blots, and 40% of the clones were expressed by at least one other cell-type including monocytes, mature T cells, and B cells. Eight cDNA clones appear to be specific for the CD4-, CD8-, CD3- T cell line, used to construct the library, as determined by Northern blot analysis. In addition, 330 cDNA clones were subjected to partial automated DNA sequence determination. Database searches, with both nucleotide and protein translations, revealed cDNAs that exhibit interesting similarities to human cell-cycle gene 1, platelet-derived growth factor receptor, c-fms oncogene (CSF-1) receptor, and members of the immunoglobulin gene superfamily. This approach of employing subtraction coupled with large scale partial cDNA sequence determination can be useful to identify genes that may be involved in early T cell growth, cellular recognition or differentiation.

Lymphotoxins - a multicomponent system of growth inhibitory and cell-lytic glycoproteins

Activated lymphocytes from experimental animals and man can release materials, termed lymphotoxins , which cause growth inhibition and cell lysis in vitro. These molecules, from human lymphocytes, are glycoproteins which can be divided into five molecular weight classes. These forms are heterogeneous, for each MW class can be further subdivided into multiple charge subclasses. It is now clear certain MW classes are interrelated and form a system of cell toxins. The larger classes (greater than 140,000 d) are associated with nonclassical antigen-binding receptors (R), which can be of T cell origin. The smaller forms (less than 90,000 d) do not express R function and are derived from the larger forms, possibly by enzymatic action. Two MW classes, one receptor-associated and one non-receptor associated, have been purified to homogeneity and their peptide composition is being studied. Functional studies reveal the larger MW forms derived from alloimmune cell populations; can induce selective and nonselective destruction of cells in vitro. Antibodies which inhibit the in vitro cell lytic ability of various human LT forms can block different classes of human lymphocyte cell killing reactions in vitro.

Intracystic papillary carcinoma of the breast. After mastectomy, radiotherapy or excisional biopsy alone

Intracystic papillary carcinoma of the breast (IPC) was distinguished from the more common papillary intraductal carcinoma (DCIS) and infiltrating duct carcinoma with a papillary pattern. IPC was defined as a solitary tumor with a pattern recognizable as carcinoma which is confined to a dilated duct. A series of 41 such cases was collected from three institutions. Twenty-nine patients underwent mastectomy; 11 of them had axillary dissections. None of these patients had metastatic disease in the axillary lymph nodes or recurrence in the follow-up period which averaged five years. Eleven patients did not have mastectomy or radiotherapy. Eight of these patients (followed for an average of ten years) had no recurrence. The only patients who developed invasive carcinoma were those with DCIS as well as IPC in the excisional biopsy. The data suggest that IPC is much more likely to be cured by local treatment than is IPC accompanied by DCIS.

Intracystic papillary carcinoma of the breast. After mastectomy, radiotherapy or excisional biopsy alone

Intracystic papillary carcinoma of the breast (IPC) was distinguished from the more common papillary intraductal carcinoma (DCIS) and infiltrating duct carcinoma with a papillary pattern. IPC was defined as a solitary tumor with a pattern recognizable as carcinoma which is confined to a dilated duct. A series of 41 such cases was collected from three institutions. Twenty-nine patients underwent mastectomy; 11 of them had axillary dissections. None of these patients had metastatic disease in the axillary lymph nodes or recurrence in the follow-up period which averaged five years. Eleven patients did not have mastectomy or radiotherapy. Eight of these patients (followed for an average of ten years) had no recurrence. The only patients who developed invasive carcinoma were those with DCIS as well as IPC in the excisional biopsy. The data suggest that IPC is much more likely to be cured by local treatment than is IPC accompanied by DCIS.

Malignant lymphoma obscured by concomitant extensive epithelioid granulomas: report of three cases with similar clinicopathologic features

Three similar cases are described of an unusual combination of malignant lymphoma and extensive non-necrotic granulomas. The three patients presented with prominent splenomegaly without peripheral lymphadenopathy. They had normal or moderately elevated lymphocyte counts, abnormal lymphoid cells in the peripheral blood and bone marrow, and abnormalities of serum immunoglobulins. The lymphoid tumor was difficult to recognize but it was best identified in abdominal lymph nodes, it was composed of small atypical lymphocytes proliferating in a vaguely nodular pattern. The presence of multiple epithelioid granulomas obscured the neoplastic proliferation in the spleens and misled or delayed the final interpretation of the malignant disease. Abdominal lymph nodes and liver also contained granulomas although to a lesser extent. Studies of the lymphocyte surface characteristics in one patient suggested that the neoplasm derived from a monoclonal proliferation of B cells. The relationship between the exuberant epithelioid granulomas and the underlying neoplastic lymphoid proliferation is not clear. Regardless of whether it represents a distinct clinicopathological entity, recognition of this remarkable association has important practical implications since the lesions may be erroneously interpreted by the pathologist.