Cross-correlation between stress, pain, physical activity, and temporalis muscle EMG in tension-type headache

Thirty-six tension-type headache subjects and 36 non-headache matched controls recorded their temporalis muscle electromyographic (EMG) activity and their pain intensity, stress and physical activity levels in a daily diary. Measurements were performed every 30 min for 6 days (EMG 3 days only). A time-lagged cross-correlational analysis between pain, stress, physical activity, and EMG shows that the highest correlation coefficient values occurred between pain and stress at the same ( r =0.33) and at the two preceding 0.5 h time points ( r =0.21 and r =0.26) in the headache group. Virtually no correlation was found between pain, stress, or physical activity with EMG for either group. These data show that temporalis muscle activity levels were not related to the rise and fall of the subjects' pain or stress levels. Conversely, elevated stress appeared to be highly related to pain; it occurs as both an antecedent and simultaneous event with elevated headache pain.     

Role of DNA hypomethylation in the development of the resistance to doxorubicin in human MCF-7 breast adenocarcinoma cells

The resistance of cancer cells to chemotherapeutic agents is a major clinical problem and an important cause of treatment failure in cancer. Mechanisms that have developed to guard cancer cells against anti-cancer drugs are major barriers to successful anti-cancer therapy. Therefore, the identification of novel mechanisms of cellular resistance holds the promise of leading to better treatments for cancer patients. In the present study, we used human MCF-7 breast adenocarcinoma cell line and its doxorubicin-resistant variant MCF-7/R to determine the role of alterations of DNA methylation of chemoresitance-related genes, such as multidrug resistance 1 (MDR1), glutathione-S-transferase (GSTpi), O(6)-methylguanine DNA methyltransferase (MGMT), and urokinase (Upa), in the development of drug resistance. The promoter regions of MDR1, GSTpi, MGMT, and Upa genes were highly methylated in MCF-7 cell line but not in its MCF-7/R drug resistant variant. The hypomethylated status of MDR1 gene was associated with overexpression of P-glycoprotein. We hypothesize that acquirement of doxorubicin resistance of MCF-7 cells is associated with DNA hypomethylation of the promoter regions of the MDR1, GSTpi, MGMT, and Upa genes.     

Involvement of microRNA-451 in resistance of the MCF-7 breast cancer cells to chemotherapeutic drug doxorubicin

Many chemotherapy regiments are successfully used to treat breast cancer; however, often breast cancer cells develop drug resistance that usually leads to a relapse and worsening of prognosis. We have shown recently that epigenetic changes such as DNA methylation and histone modifications play an important role in breast cancer cell resistance to chemotherapeutic agents. Another mechanism of gene expression control is mediated via the function of small regulatory RNA, particularly microRNA (miRNA); its role in cancer cell drug resistance still remains unexplored. In the present study, we investigated the role of miRNA in the resistance of human MCF-7 breast adenocarcinoma cells to doxorubicin (DOX). Here, we for the first time show that DOX-resistant MCF-7 cells (MCF-7/DOX) exhibit a considerable dysregulation of the miRNAome profile and altered expression of miRNA processing enzymes Dicer and Argonaute 2. The mechanistic link of miRNAome deregulation and the multidrug-resistant phenotype of MCF-7/DOX cells was evidenced by a remarkable correlation between specific miRNA expression and corresponding changes in protein levels of their targets, specifically those ones that have a documented role in cancer drug resistance. Furthermore, we show that microRNA-451 regulates the expression of multidrug resistance 1 gene. More importantly, transfection of the MCF-7/DOX-resistant cells with microRNA-451 resulted in the increased sensitivity of cells to DOX, indicating that correction of altered expression of miRNA may have significant implications for therapeutic strategies aiming to overcome cancer cell resistance.     

The immunosuppressant rapamycin blocks in vitro responses to hematopoietic cytokines and inhibits recovering but not steady-state hematopoiesis in vivo

The immunosuppressive drug rapamycin suppresses T-cell activation by impairing the T-cell response to lymphokines such as interleukin-2 (IL- 2) and interleukin-4 (IL-4). In addition, rapamycin blocks the proliferative response of cell lines to a variety of hematopoietic growth factors, including interleukin-3 (IL-3), interleukin-6 (IL-6), granulocyte-colony stimulating factor (G-CSF), granulocyte macrophage- colony stimulating factor (GM-CSF), and kit ligand (KL), suggesting that it should be a strong inhibitor of hematopoiesis. In this report, we studied the effects of rapamycin on different hematopoietic cell populations in vitro and in vivo. In vitro, rapamycin inhibited the proliferation of primary bone marrow cells induced by IL-3, GM-CSF, KL, or a complex mixture of factors present in cell-conditioned media. Rapamycin also inhibited the multiplication of colony-forming cells in suspension cultures containing IL-3 plus interleukin-1 (IL-1) or interleukin-11 (IL-11) plus KL. In vivo, treatment for 10 to 28 days with high doses of rapamycin (50 mg/kg/d, orally) had no effect on myelopoiesis in normal mice, as measured by bone marrow cellularity, proliferative capacity, and number of colony-forming progenitors. In contrast, the same treatment strongly suppressed the hematopoietic recovery normally seen 10 days after an injection of 5-fluorouracil (5- FU; 150 mg/kg, intravenously [i.v.]). Thus, rapamycin may be detrimental in myelocompromised individuals. In addition, the results suggest that the rapamycin-sensitive cytokine-driven pathways are essential for hematopoietic recovery after myelodepression, but not for steady-state hematopoiesis.     

Antibodies to myeloid precursor cells in autoimmune neutropenia

Antibodies to mature blood neutrophils and to bone marrow myeloid cells have been described in the sera of some patients with apparent autoimmune neutropenia. To further explore the prevalence and specificities of antibodies to myeloid precursor cells, we evaluated sera from 148 patients with suspected autoimmune neutropenia for the presence of antibodies to neutrophils, to cultured myeloid cell lines, and to highly purified bone marrow myeloid progenitor cells. Using an immunofluorescence flow cytometric assay, we identified IgG antibodies in 42 (28%) of these sera that bound specifically to K562 cells, a multilineage cell line originally derived from a patient with chronic myelogenous leukemia. Twenty-two (15%) of the sera also contained IgG antibodies that bound specifically to the primitive myelomonocytic leukemia cell line KG1a. Twenty-five (17%) of the sera had IgG antibodies to myeloid cell lines in the absence of antibodies to mature neutrophils. There was a trend toward more severe neutropenia in patients with antibodies to K562 cells, without antineutrophil antibodies. In further studies, antibodies from 12 sera bound to mononuclear CD34+ cells that had been purified from normal human bone marrow by an immunomagnetic separation procedure. Moreover, two of these sera suppressed the growth of granulocyte-macrophage colony- forming units (CFU-GM) in methylcellulose cultures. The presence of antibodies to primitive hematopoietic cells in the sera of some patients with suspected immune neutropenia suggests that these antibodies may have a role in the pathogenesis of the neutropenia observed.     

Hemoglobin E trait reexamined: a cause of microcytosis and erythrocytosis

The current Indochinese resettlement program in the United States has resulted in an increase in the number of persons with hemoglobin E trait. American physicians should be aware of the hematologic expressions of this innocuous condition. The hematologic manifestations of 21 persons with hemoglobin E trait were evaluated. The subjects were of Tai-dam, Vietnamese, Chinese, Laotian, and European origin. These studies showed uniform hematologic manifestations in hemoglobin E trait, characterized by slight microcytosis, by morphologic features resembling those of thalassemia minor, and often by increased erythrocyte count. Hemoglobin instability also was confirmed.     

Unequal crossing-over: a common basis of single alpha-globin genes in Asians and American blacks with hemoglobin-H disease

The alpha-globin genes of five black Americans, two Chinese, and five Filipinos with HbH disease (an alpha-thalassemia state in which there is a single functional alpha gene) were analyzed by restriction endonuclease techniques. All subjects were found to have one chromosome 16, lacking both alpha genes, and another containing a single alpha gene (--/-alpha). Restriction endonuclease patterns of the DNA obtained from all 12 subjects were identical and compatible with unequal crossing-over as the mechanism of origin of the single alpha gene in these individuals.