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Sacks SL, Aoki FY, Diaz-Mitoma F, Sellors J, Shafran SD. Patient-initiated, twice-daily oral famciclovir for early recurrent genital herpes. A randomized, double-blind multicenter trial. Canadian Famciclovir Study Group. JAMA 1996; 276:44-9. [PMID: 8667538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE To compare the efficacy and safety of episodic patient-initiated oral famciclovir with placebo in recurrent genital herpes. DESIGN Randomized, double-blind, frequent-observation, dose-ranging study comparing twice-daily 125-mg, 250-mg, or 500-mg oral famciclovir with placebo. Patients initiated therapy after self-culturing, reported to the clinic within 12 hours, and were assessed twice daily for at least 5 days. SETTING Fifteen Canadian university, private practice, or public outpatient clinics. PATIENTS A total of 692 patients with culture-proven recurrent genital herpes were randomized; 467 patients experienced a symptomatic episode and commenced treatment. MAIN OUTCOME MEASURE Time to complete healing of all lesions. RESULTS Famciclovir (all doses) was significantly more effective than placebo in reducing time to healing, time to cessation of viral shedding, and durations of lesion edema, vesicles, ulcers, and crusts. Times to cessation of all symptoms and of moderate to severe lesion tenderness, pain, and burning were also reduced. Patients who initiated famciclovir prior to viral shedding were more likely to not shed virus throughout. All doses were equally effective, safe, and well tolerated. CONCLUSIONS Oral famciclovir reduced the onset and duration of viral shedding, lesion persistence, and uncomfortable symptoms. Several individual symptoms and lesion stages were also reduced in duration by this episodic therapy. Additionally, our twice-daily observation trial design proved to be a helpful tool for studying recurrent disease. Episodic oral famciclovir provides a convenient and effective alternative for those patients with recurrent genital herpes whose frequency rates do not require continuous antiviral suppression.
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Daftarian PM, Kumar A, Kryworuchko M, Diaz-Mitoma F. IL-10 production is enhanced in human T cells by IL-12 and IL-6 and in monocytes by tumor necrosis factor-alpha. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1996; 157:12-20. [PMID: 8683105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
IL-10, an immunoregulatory cytokine produced by T cells and monocytes, inhibits the expression of inflammatory and hemopoietic cytokines as well as its own expression. To evaluate the regulation of IL-10 production by T cells and monocytes, we measured IL-10 levels by ELISA in supernatants of PHA-stimulated PBMC following depletion of either T cells or monocytes. IL-10 production was significantly down-regulated in both T cell- and monocyte-depleted PBMC compared with undepleted PBMC, and IL-10 production could be restored by the addition of monocyte-conditioned medium (supernatant of PHA-stimulated, T cell-depleted PBMC), suggesting that IL-10 production by T cells is regulated by a monokine(s) produced by activated monocytes. To further clarify the monokine(s) responsible for IL-10 induction, we stimulated monocyte-depleted PBMC, purified CD4+, and CD8+ T cells with PHA and measured IL-10 production by ELISA and semiquantitative reverse transcriptase-PCR following monokine(s) addition. Addition of IL-6 and IL-12 enhanced IL-10 production in monocyte-depleted PBMC in a dose-dependent and additive manner. Furthermore, anti-IL-6 and anti-IL-12 Abs neutralized the IL-10-inductive effect of monocyte-conditioned medium. Similarly, IL-12 and IL-6 induced IL-10 production by purified CD4+ and CD8+ T cells. With respect to regulation of IL-10 produced by monocytes, TNF-alpha was found to induce IL-10 production by resting as well as by LPS-stimulated purified monocytes/macrophages. Taken together, these findings suggest that IL-10 production by human T cells and monocytes is differentially regulated. IL-12 and/or IL-6 can induce the expression of IL-10 by PHA-stimulated T cells, whereas TNF-alpha induces IL-10 production by monocytes. Since IL-10 inhibits the production of IL-6, IL-12, and TNF-alpha, these results may indicate a potential mechanism of negative feedback regulation of the immune response.
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Daftarian PM, Kumar A, Kryworuchko M, Diaz-Mitoma F. IL-10 production is enhanced in human T cells by IL-12 and IL-6 and in monocytes by tumor necrosis factor-alpha. THE JOURNAL OF IMMUNOLOGY 1996. [DOI: 10.4049/jimmunol.157.1.12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
IL-10, an immunoregulatory cytokine produced by T cells and monocytes, inhibits the expression of inflammatory and hemopoietic cytokines as well as its own expression. To evaluate the regulation of IL-10 production by T cells and monocytes, we measured IL-10 levels by ELISA in supernatants of PHA-stimulated PBMC following depletion of either T cells or monocytes. IL-10 production was significantly down-regulated in both T cell- and monocyte-depleted PBMC compared with undepleted PBMC, and IL-10 production could be restored by the addition of monocyte-conditioned medium (supernatant of PHA-stimulated, T cell-depleted PBMC), suggesting that IL-10 production by T cells is regulated by a monokine(s) produced by activated monocytes. To further clarify the monokine(s) responsible for IL-10 induction, we stimulated monocyte-depleted PBMC, purified CD4+, and CD8+ T cells with PHA and measured IL-10 production by ELISA and semiquantitative reverse transcriptase-PCR following monokine(s) addition. Addition of IL-6 and IL-12 enhanced IL-10 production in monocyte-depleted PBMC in a dose-dependent and additive manner. Furthermore, anti-IL-6 and anti-IL-12 Abs neutralized the IL-10-inductive effect of monocyte-conditioned medium. Similarly, IL-12 and IL-6 induced IL-10 production by purified CD4+ and CD8+ T cells. With respect to regulation of IL-10 produced by monocytes, TNF-alpha was found to induce IL-10 production by resting as well as by LPS-stimulated purified monocytes/macrophages. Taken together, these findings suggest that IL-10 production by human T cells and monocytes is differentially regulated. IL-12 and/or IL-6 can induce the expression of IL-10 by PHA-stimulated T cells, whereas TNF-alpha induces IL-10 production by monocytes. Since IL-10 inhibits the production of IL-6, IL-12, and TNF-alpha, these results may indicate a potential mechanism of negative feedback regulation of the immune response.
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Singh B, Merchant P, Walker CR, Kryworuchko M, Diaz-Mitoma F. Interleukin-6 expression in cord blood of patients with clinical chorioamnionitis. Pediatr Res 1996; 39:976-9. [PMID: 8725257 DOI: 10.1203/00006450-199606000-00008] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The objective of this study was to define whether IL-6 is an early marker of infection in the newborn. To correlate the occurrence of clinical chorioamnionitis with the levels of IL-6 expression in neonates, IL-6 was measured in cord plasma by ELISA and in mononuclear cells by reverse transcriptase-PCR before and after mitogenic stimulation. Eight neonates were included in each of the following four groups: elective cesarean section, uncomplicated normal spontaneous vaginal delivery, delivery after prolonged rupture of amniotic membranes with no evidence of chorioamnionitis, and delivery with evidence of chorioamnionitis. All 32 neonates were clinically well after delivery, and all 16 babies with prolonged rupture of membranes or clinical chorioamnionitis had negative blood cultures. Elevated IL-6 levels were found only in neonates born to mothers with chorioamnionitis (119.7 +/- 33.5 pg/mL versus 2.71 +/- 0.59 pg/mL, p < 0.005). Mononuclear cells from five of these neonates expressed no IL-6 mRNA in vivo despite elevated levels of IL-6 in their cord plasma. Cord blood mononuclear cells from healthy term babies were capable of synthesizing IL-6 in vitro in response to stimulation with bacterial lipopolysaccharide. These results suggest that IL-6 levels in cord plasma increased with clinical chorioamnionitis, despite the lack of evidence of infection in the neonates. Therefore, we conclude that, although a high level of IL-6 may be a good marker of chorioamnionitis, it may not be a specific marker of infection in the newborn.
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Creery WD, Diaz-Mitoma F, Filion L, Kumar A. Differential modulation of B7-1 and B7-2 isoform expression on human monocytes by cytokines which influence the development of T helper cell phenotype. Eur J Immunol 1996; 26:1273-7. [PMID: 8647204 DOI: 10.1002/eji.1830260614] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The co-stimulatory molecules B7-1/B7-2 expressed on the surface of antigen-presenting cells have been suggested to influence the development of T helper 1 (Th1)-versus Th2-immune responses. These studies were conducted to elucidate the effect of immunoregulatory cytokines which influence the development of Th1/Th2 immune responses on the expression of the B7 isoforms B7-1 and B7-2 on resting and activated human monocytes and B cells. Interleukin (IL)-4 and IL-10, which induce the development of Th2 immune responses, down-regulated B7-2 and moderately up-regulated B7-1 expression on resting CD14+ monocytes in peripheral blood mononuclear cells. Interferon-gamma (IFN-gamma), which induces the development of Th1 immune responses, enhanced the expression of both B7-1 and B7-2 isoforms. Tumor necrosis factor (TNF)-alpha, which elicits both Th1- and Th2 characteristics depending on experimental conditions, down-regulated B7-2 but did not alter B7-1 expression. The effect of TNF-alpha and B7-2 expression is not mediated through endogenously produced IL-10, as addition of anti-IL-10 antibodies did not restore B7-2 expression. None of the other cytokines tested, including IL-1 alpha, IL-1 beta, IL-2, IL-5, IL-6, IL-12, granulocyte/macrophage colony-stimulating factor (GM-CSF), and transforming growth factor (TGF)-alpha, modulated the expression of B7 isoforms on resting monocytes. Lipoolysaccharide stimulation of monocytes down-regulated B7-2 and up-regulated B7-1 expression in a manner similar to IL-10. The expression of B7-1 and B7-2 on purified B cells were not altered by any of the cytokines tested, including IL-1 alpha, IL-1 beta, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, IFN-gamma, TNF-alpha, TGF-alpha and GM-CSF. Taken together, our results suggest that the cytokines which induce Th1/Th2 immune responses exert differential effects on B7 isoform expression on resting monocytes but have no effect on resting or activated B cells.
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Diaz-Mitoma F, Ruben M, Sacks S, MacPherson P, Caissie G. Detection of viral DNA to evaluate outcome of antiviral treatment of patients with recurrent genital herpes. J Clin Microbiol 1996; 34:657-63. [PMID: 8904433 PMCID: PMC228865 DOI: 10.1128/jcm.34.3.657-663.1996] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Culture of infectious virus, PCR amplification of viral DNA, and the appearance of genital skin lesions were used as markers to study the course of a recurrence of genital herpes in 40 patients treated with famciclovir or placebo. The highest frequency of patients with skin lesions occurred within the first 36 h following the onset of a recurrence, which also corresponded to the peak in the production of virus. While the timing of the peak in skin lesions was independent of the type of treatment, the frequency of lesions and the release of virus at the lesion site were both reduced by famciclovir treatment. Furthermore, patients receiving this antiviral agent showed a more rapid recovery time and a shorter period during which viral DNA could be detected at the lesion. PCR and then Southern blot hybridization greatly enhanced our ability to detect herpes simplex virus at the lesion site. This procedure proved to be of greater diagnostic value in assessing genital herpes than the standard culture method currently used. In addition, PCR was more sensitive in evaluating treatment effectiveness.
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King WJ, MacDonald NE, Wells G, Huang J, Allen U, Chan F, Ferris W, Diaz-Mitoma F, Ashton F. Total and functional antibody response to a quadrivalent meningococcal polysaccharide vaccine among children. J Pediatr 1996; 128:196-202. [PMID: 8636811 DOI: 10.1016/s0022-3476(96)70389-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE To determine total and functional serogroup C antibody response after vaccination with a quadrivalent meningococcal polysaccharide vaccine. DESIGN Prospective, before and after intervention study. SUBJECTS Study subjects were between the ages of 0.5 and 19.9 years, and were eligible for a community-wide public health immunization campaign against Neisseria meningitidis serogroup C. METHODS Total and functional antibody response was measured by enzyme-linked immunosorbent assay and bactericidal assay, respectively. RESULTS One month after vaccination, total capsular polysaccharide antibody significantly increased in all age groups; a significant rise in bactericidal antibody, that correlated with total capsular polysaccharide antibody, was seen in children 18 months of age and older. At 1 year bactericidal antibody titers were maintained but capsular polysaccharide antibody declined substantially in children younger than 5 years. CONCLUSION Total capsular polysaccharide antibody concentration appears to be a useful surrogate measure of bactericidal antibody in children 18 months and older. Children who originally received the vaccine at less than 18 months of age should be considered for revaccination if there is a new or continuing risk of disease. Because of the differences in the total and bactericidal antibodies formed, vaccine efficacy trials are required to define which serologic measures are associated with protection.
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Tanner JE, Alfieri C, Chatila TA, Diaz-Mitoma F. Induction of interleukin-6 after stimulation of human B-cell CD21 by Epstein-Barr virus glycoproteins gp350 and gp220. J Virol 1996; 70:570-5. [PMID: 8523572 PMCID: PMC189846 DOI: 10.1128/jvi.70.1.570-575.1996] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The cellular receptor for Epstein-Barr virus (EBV) is the type 2 complement receptor, CD21. At initial infection, EBV virion glycoproteins gp350 and gp220 bind to CD21. We report here that the cross-linking of CD21 by gp350/220 results in increased amounts of interleukin 6 (IL-6) RNA and IL-6 protein. This effect could be blocked with anti-gp350/220 and anti-CD21 monoclonal antibodies. Induction of IL-6 in B cells by EBV could be mimicked by treatment with the protein kinase C (PKC) activator phorbol 12,13-dibutyrate but not with the calcium ionophore ionomycin. IL-6 induction by EBV was inhibited with the PKC-specific inhibitor bisindolylmaleimide or the protein tyrosine kinase inhibitors methyl 2,5-dihydroxycinnamate and herbimycin A, indicating that the induction of IL-6 following CD21 cross-linking is mediated through PKC- and protein tyrosine kinase-dependent pathways.
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Daftarian MP, Diaz-Mitoma F, Creery WD, Cameron W, Kumar A. Dysregulated production of interleukin-10 (IL-10) and IL-12 by peripheral blood lymphocytes from human immunodeficiency virus-infected individuals is associated with altered proliferative responses to recall antigens. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 1995; 2:712-8. [PMID: 8574836 PMCID: PMC170227 DOI: 10.1128/cdli.2.6.712-718.1995] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The loss of immune function following infection with human immunodeficiency virus (HIV) may result from altered production of immunoregulatory cytokines such as interleukin-10 (IL-10) and IL-12. In this study, we analyzed IL-10 and IL-12 production by mitogen-stimulated peripheral blood mononuclear cells (PBMC) from HIV+ individuals and correlated their levels with proliferative responses to the recall antigens HIV p25 and influenza virus. We report two distinct groups of HIV+ patients. One group produced small amounts of IL-10, had PBMC that proliferated in response to recall antigens, and demonstrated enhanced recall antigen-induced proliferation upon addition of anti-IL-10 antibodies and/or IL-12. Conversely, the second group produced high levels of IL-10, had PBMC that failed to proliferate to recall antigens, and did not demonstrate enhanced proliferation upon addition of anti-IL-10 antibodies and/or IL-12. Mitogen-stimulated PBMC from both groups produced significantly lower levels of IL-12 than did those from HIV- controls. Analysis of the source of the IL-10-producing cell subset in PBMC demonstrated that in HIV+ individuals, IL-10 is produced by monocytes, while in HIV- controls, it is produced by both T cells and monocytes. Taken together, our results suggest that monocytes from HIV+ individuals secrete decreased amounts of IL-12, a Th1-type cytokine, which may lead to the development of Th2-type responses characterized by high IL-10 secretion and immune dysfunction.
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Kumar A, Kurl RN, Kryworuchko M, Diaz-Mitoma F, Sharma S. Differential effect of heat shock on RNA metabolism in human Burkitt's lymphoma B-cell lines. Leuk Res 1995; 19:831-40. [PMID: 8551800 DOI: 10.1016/0145-2126(95)00063-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Thermal stress induces expression of a family of heat shock proteins which may regulate the synthesis of various cellular genes. We investigated the effect of heat shock on polyadenylation in Epstein-Barr Virus (EBV) negative and EBV transformed human Burkitt's lymphoma (BL) B-cell lines. Incubation of the BL B-cell line P3HR-1, carrying the defective EBV genome [EBV nuclear antigen-2 gene deletion] at 46 degrees C for 15 min increased nuclear poly(A) polymerase (PAP) activity. Thereafter, enzymatic activity declined and at 60 min it was reduced to about 50% of that observed in cells incubated at 37 degrees C. In contrast, no significant increase in PAP activity was observed at 15 min or thereafter in an EBV- BL cell line, ST-486, in response to elevated temperature. Furthermore, no heat shock mediated change in nuclear poly(A)-specific endonuclease activity was observed in either P3HR-1 or ST-486 cells suggesting a specific effect on PAP activity. However, thermal stress dependent increase in c-myc expression was detected only in P3HR-I cells. These results suggest an association between EBV transformation and enhanced expression of c-myc and PAP activity. To further determine the role of EBV, and EBV- BL cell line, BL-30, and BL-30 cells infected in vitro with a wild type strain of EBV, BL-30/B95-8, were investigated. BL-30/B-95-8, unlike the parental BL-30 cells, exhibited c-myc and PAP gene upregulation at 15 min but were downregulated at 60 min following exposure of cells to elevated temperatures. These results suggest that infection of human B-cells with EBV is associated with their ability to respond to thermal stress by increased PAP activity which may stabilize mRNA through enhanced polyadenylation.
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Diaz-Mitoma F, Kumar A, Karimi S, Kryworuchko M, Daftarian MP, Creery WD, Filion LG, Cameron W. Expression of IL-10, IL-4 and interferon-gamma in unstimulated and mitogen-stimulated peripheral blood lymphocytes from HIV-seropositive patients. Clin Exp Immunol 1995; 102:31-9. [PMID: 7554396 PMCID: PMC1553336 DOI: 10.1111/j.1365-2249.1995.tb06632.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Infection of immune cells with HIV induces dysregulation of cytokines which may play a vital role in HIV pathogenesis. We analysed the expression of T helper type 1 (Th1) (interferon-gamma (IFN-gamma)) and Th2 (IL-4, IL-10) type cytokines in peripheral blood lymphocytes (PBL) from HIV+ patients. The semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR) analysis revealed that IFN-gamma mRNA in unstimulated PBL was significantly decreased and IL-10 mRNA was significantly upregulated in patients with < 400 CD4+ T cells/mm3 (n = 30) as compared to patients with > 400 CD4+ T cells/mm3 (n = 6) and normal controls (n = 16). In addition, IL-10 mRNA levels were inversely associated with IFN-gamma expression. Similar results were obtained by measuring IL-10 production in the supernatants of PBL cultured in vitro without stimulation by employing an enzyme immunosorbent assay (ELISA). However, the levels of IL-4 and IFN-gamma produced by unstimulated PBL were undetectable by ELISA. Mitogen stimulation of PBL revealed two groups of HIV+ individuals based on IL-10 production. PBL from one set of individuals produced low levels of IL-10 (low IL-10 producers) whereas the other group produced IL-10 comparable to that of normal controls (IL-10 producers). Production of IL-4 was significantly reduced in HIV+ individuals with < 400 CD4+ T cells/mm3 as compared to the normal controls. However, ability to produce IFN-gamma by mitogen-stimulated total PBL and CD4+ purified cells was not impaired in HIV+ individuals. These results suggest that unstimulated and mitogen-stimulated PBL of HIV+ individuals exhibit dysregulation of Th2 type cytokines which may play a role in HIV immunopathogenesis.
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Kryworuckho M, Diaz-Mitoma F, Kumar A. CD44 isoforms containing exons V6 and V7 are differentially expressed on mitogenically stimulated normal and Epstein-Barr virus-transformed human B cells. Immunology 1995; 86:41-8. [PMID: 7590880 PMCID: PMC1383808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
CD44, a cell adhesion molecule, exists in multiple isoforms that are generated by RNA alternative splicing. CD44 isoforms containing exon V6 (CD44 V6) have been associated with tumorigenesis and metastasis. We investigated the association between human B-cell activation and CD44 V6 isoform expression by analysing its expression in resting and mitogenically stimulated B cells. Results showed that resting B cells expressed the CD44 H (no variable exon) isoform alone. Activation of B cells [phorbol myristate acetate (PMA), surface immunoglobulin cross-linking alone or in the presence of interleukin-2 (IL-2)] induced CD44E (variable exon V8-10), R2 (VIO) and CD44 isoforms containing exons V6 and/or V7 (CD44 V6/V7). Epstein-Barr virus (EBV) infection of B cells, an alternative method of B-cell activation, induced the expression of CD44 E and R2 but not CD44 V6/V7. These results indicate that CD44 V6/V7 expression depends on the mode of activation. CD44 isoform expression was also investigated in a panel of EBV-negative and EBV-positive Burkitt's lymphoma (BL) B-cell lines. EBV-negative BL cells did not express CD44. In contrast, EBV-positive BL cells expressed CD44 H, R2 and E but not CD44 V6/V7 isoforms, suggesting an association between EBV infection and CD44 isoform induction. To determine directly the role of EBV in CD44 isoform induction, an EBV-negative BL cell line, BL30 (negative for all isoforms of CD44), BL30 infected in vitro with the EBNA-2-defective P3HR1 (BL30/P3HR1), and the wild-type B95-8 strain of EBV (BL30/B95-8) were examined. The parental BL30 cells infected with the wild-type EBV strain, but not with the P3HR-1 strain, expressed CD44 H, R2 and E isoforms, as seen in EBV-immortalized B cells. These studies suggest that (1) alternative splicing of CD44 isoforms is differentially regulated depending on the mode and state of cell activation, and that (2) the CD44 V6/V7 isoforms may represent B-cell activation antigens that are induced by mitogenic stimulation but not following EBV infection.
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Mackenzie A, Fuite LA, Chan FT, King J, Allen U, MacDonald N, Diaz-Mitoma F. Incidence and pathogenicity of Arcanobacterium haemolyticum during a 2-year study in Ottawa. Clin Infect Dis 1995; 21:177-81. [PMID: 7578727 DOI: 10.1093/clinids/21.1.177] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Arcanobacterium haemolyticum has been described as a rare cause of systemic invasive disease and is occasionally isolated from throat swabs. We describe a 2-year study of the incidence and clinical features of A. haemolyticus infection in a pediatric and adolescent population. A total of 11,620 throat swabs were examined for A. haemolyticum with use of a locally developed selective medium. Controls (2,241) were healthy students who were recruited from a separate study. A. haemolyticum was isolated from 42 patients, with the maximum incidence in the 15 to 18-year-old age group; in this subset the incidence was 2.5%. There were no isolates of A. haemolyticum found in the healthy controls, and the difference in incidence between patients and controls in the 15 to 18-year-old age group was highly significant (P < .01). Approximately half of the patients infected with A. haemolyticum had a rash. In 5 patients, A. haemolyticum was associated with a positive monospot test. The organism was highly susceptible to erythromycin and less susceptible to penicillin. The evidence from this study suggests that A. haemolyticum may be a pathogen with maximum incidence in the 15 to 18-year-old age group.
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Daftarian MP, Filion LG, Cameron W, Conway B, Roy R, Tropper F, Diaz-Mitoma F. Immune response to sulfamethoxazole in patients with AIDS. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 1995; 2:199-204. [PMID: 7697529 PMCID: PMC170127 DOI: 10.1128/cdli.2.2.199-204.1995] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Antibody- and cell-mediated responses to sulfamethoxazole (SMX) were analyzed in AIDS patients with or without a history of hypersensitivity and in negative controls. In 20 of 20 (P < 0.01) human immunodeficiency virus (HIV)-seropositive patients with skin reactions to cotrimoxazole, we found SMX-specific antibodies, while only 9 of 20 and 17 of 20 HIV-seropositive patients without a history of hypersensitivity to cotrimoxazole had SMX-specific immunoglobulin M (IgM) and IgG, respectively. The levels of specific IgM and IgG were higher in patients with skin reactions than in patients without reactions (IgM, 1.0 +/- 0.19 versus 0.47 +/- 0.23 [P < 0.001]; IgG, 0.68 +/- 0.15 versus 0.47 +/- 0.14 [P < 0.001] [mean optical density values +/- standard deviations]). Seronegative controls with no history of exposure to sulfa compounds did not have SMX-specific IgG or IgM antibodies, and controls with a history of intake of SMX with or without reactions had low levels of IgG and IgM. The SMX-specific IgG subclasses were exclusively IgG1 and IgG3. None of the patients had detectable SMX-specific IgE or IgA antibodies nor did they exhibit a cell-mediated response as measured by a lymphocyte proliferation assay. Antibodies to SMX recognized N-acetyl-sulfonamide, N-(2-thiazolyl)-sulfanilamide, sulfadiazine, and sulfisoxazole but did not recognize sulfanilamide or 3-amino-5-methyl isoxazole in an inhibition assay. It is not known whether the SMX-specific antibodies associated with hypersensitivity reactions to SMX in HIV-seropositive patients have a pathogenic role in these reactions. Sulfanilamide or 3-amino-5-methyl isoxazole, on the other hand, could be potential alternative therapies in HIV-seropositive patients with a history of skin reactions to SMX.
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Chan FT, Guan MX, Mackenzie AM, Diaz-Mitoma F. Susceptibility testing of Dientamoeba fragilis ATCC 30948 with iodoquinol, paromomycin, tetracycline, and metronidazole. Antimicrob Agents Chemother 1994; 38:1157-60. [PMID: 8067755 PMCID: PMC188168 DOI: 10.1128/aac.38.5.1157] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Susceptibility testing was performed on Dientamoeba fragilis ATCC 30948 in a dixenic culture with Klebsiella pneumoniae and Bacteroides vulgatus. D. fragilis was cocultured with the bacteria in TYGM-9 medium (ATCC medium 1171). The activities of antiparasitic drugs were assessed by counting viable D. fragilis trophozoites with a hemacytometer by trypan blue exclusion. The minimal amebicidal concentrations of the following four drugs were determined: iodoquinol at 128 micrograms/ml, paromomycin at 16 micrograms/ml, tetracycline (questionably) at 32 micrograms/ml, and metronidazole at 32 micrograms/ml.
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Miller H, Milk R, Diaz-Mitoma F. Comparison of the VIDAS RSV assay and the Abbott Testpack RSV with direct immunofluorescence for detection of respiratory syncytial virus in nasopharyngeal aspirates. J Clin Microbiol 1993; 31:1336-8. [PMID: 8501239 PMCID: PMC262932 DOI: 10.1128/jcm.31.5.1336-1338.1993] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The sensitivity and accuracy of the VIDAS RSV assay in testing fresh specimens were 82.7 and 87.1%, respectively, whereas specimens previously frozen at -70 degrees C gave a sensitivity of 96.2% and an accuracy of 95.4%. The sensitivity and accuracy of Abbott Testpack RSV were 92.6 and 91.3% for fresh specimens and 86.8 and 88.1% for frozen specimens. The advantages and drawbacks of the two assays are discussed.
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Preiksaitis JK, Diaz-Mitoma F, Mirzayans F, Roberts S, Tyrrell DL. Quantitative oropharyngeal Epstein-Barr virus shedding in renal and cardiac transplant recipients: relationship to immunosuppressive therapy, serologic responses, and the risk of posttransplant lymphoproliferative disorder. J Infect Dis 1992; 166:986-94. [PMID: 1328412 DOI: 10.1093/infdis/166.5.986] [Citation(s) in RCA: 110] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Epstein-Barr virus (EBV) infection plays a major role in the pathogenesis of posttransplant lymphoproliferative disorder (PTLD). Quantitative oropharyngeal EBV shedding measured by a DNA-DNA dot blot assay and the genotype of isolates determined by a polymerase chain reaction assay were studied in 23 renal and 23 cardiac transplant recipients followed over the first posttransplant year. Five patients developed PTLD and two additional PTLD renal transplant recipients were studied from the time of diagnosis. Significantly higher levels of EBV were observed in primary versus reactivation infection (P < .04) when sequential courses of antilymphocyte globulins or > 4 g of methylprednisolone were used in the first 6 months after transplant and in patients with versus those without PTLD (P < .04), although the former group had a high incidence of primary infection. Patients with the highest EBV shedding had the poorest serologic responses. All PTLD patients shed EBV-1, which was also shed by patients without PTLD.
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Diaz-Mitoma F, Ruiz A, Flowerdew G, Houston S, Romanowski B, Kovithavongs T, Preiksaitis J, Tyrrell DL. High levels of Epstein-Barr virus in the oropharynx: a predictor of disease progression in human immunodeficiency virus infection. J Med Virol 1990; 31:69-75. [PMID: 2167351 DOI: 10.1002/jmv.1890310202] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The role of Epstein-Barr virus (EBV) on the progression of human immunodeficiency virus (HIV) infection is not well defined. The objective of this prospective study was to determine the prevalence of EBV excretion and the role that EBV might have on HIV disease progression. Fifty-two homosexual males were studied, all of whom had positive EBV serology. Twenty-four of the 27 HIV-seropositive and 14 of the 25 HIV-seronegative subjects had detectable levels of EBV DNA in oropharyngeal cells. In addition to a greater prevalence of detectable EBV, the level of excretion was higher among HIV-seropositives than among HIV-seronegatives, and higher among group III than among group II HIV-seropositive men. These results are consistent with earlier studies showing a relationship between immunosuppression and EBV reactivation. The EBV excretion levels in a control group of 52 age-matched heterosexual males were substantially lower than those found in the homosexual group. In a proportional hazards regression analysis EBV excretion was found to be the best single predictor of progression of HIV infection (P less than 0.001). HIV p24 core antigenemia (P = 0.048) and low EBNA (P = 0.024) were significant predictors independent of EBV excretion. Whether EV directly accelerates the time to progression or is merely a marker of underlying subclinical immunosuppression remains an open question.
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Diaz-Mitoma F, Harding GK, Hoban DJ, Roberts RS, Low DE. Clinical significance of a test for slime production in ventriculoperitoneal shunt infections caused by coagulase-negative staphylococci. J Infect Dis 1987; 156:555-60. [PMID: 3624905 DOI: 10.1093/infdis/156.4.555] [Citation(s) in RCA: 98] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Coagulase-negative staphylococci (CNST) are the most-common cause of ventriculoperitoneal shunt infections. Some of these strains produce a slime-like substance. We reviewed 19 episodes of ventriculoperitoneal shunt infections due to CNST in 17 patients. Eleven episodes of infection were caused by slime-producing CNST and eight by non-slime-producing CNST. Shunt obstruction and abdominal pain occurred more frequently when infectious episodes were due to slime-producing CNST than to non-slime-producing CNST (P less than .05). Despite appropriate antimicrobial therapy, the mean duration of fever was longer and the failure to eradicate the infecting organisms was more frequent when the infectious episodes were due to slime-producing CNST than to non-slime-producing CNST (P less than .025). Discriminate function analysis found, however, that only failure to eradicate the infecting organism (by antimicrobial therapy) occurred more frequently in infectious episodes due to slime-producing CNST than to non-slime-producing CNST (P = .01).
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Vanast WJ, Diaz-Mitoma F, Tyrrell DL. Epstein-Barr virus-related syndromes: implications for headache research. Headache 1987; 27:321-4. [PMID: 2820897 DOI: 10.1111/j.1526-4610.1987.hed2706321.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Vanast WJ, Diaz-Mitoma F, Tyrrell DL. Hypothesis: chronic benign daily headache is an immune disorder with a viral trigger. Headache 1987; 27:138-42. [PMID: 3036747 DOI: 10.1111/j.1526-4610.1987.hed2703138.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Diaz-Mitoma F, Vanast WJ, Tyrrell DL. Increased frequency of Epstein-Barr virus excretion in patients with new daily persistent headaches. Lancet 1987; 1:411-5. [PMID: 2880216 DOI: 10.1016/s0140-6736(87)90119-x] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In a case-control study 27 (84%) of 32 patients with new daily persistent headaches (NDPH) and 8 (25%) of 32 controls had evidence of Epstein-Barr virus (EBV) "active" infection, as demonstrated by EBV excretion and/or early antigen titre above 1:32. 20 (62%) patients and 4 (12%) controls were excreting EBV in the oropharynx, as determined by a dot hybridisation assay. The mean titre of IgG antibodies to early antigen was significantly higher in patients than controls. EBV reactivation may be important in the pathogenesis of NDPH. Alternatively, patients with NDPH may be unusually prone to EBV reactivation.
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Diaz-Mitoma F, Preiksaitis JK, Leung WC, Tyrrell DL. DNA-DNA dot hybridization to detect Epstein-Barr virus in throat washings. J Infect Dis 1987; 155:297-303. [PMID: 3027193 DOI: 10.1093/infdis/155.2.297] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
To compare the abilities of the nucleic acid dot hybridization assay and the cord blood lymphocyte transformation assay to detect Epstein-Barr virus (EBV), we examined throat washings from healthy control subjects (nine EBV-seronegative and 51 EBV-seropositive), patients with acute infectious mononucleosis, and renal transplant recipients. The dot hybridization assay detected EBV excretion in four (8%) of the EBV-seropositive controls; three of these four were also positive by the lymphocyte transformation assay. Throat washings from seven (87.5%) of eight patients with acute infectious mononucleosis were positive by both assays. EBV was present in throat washings from 13 (50%) of 26 renal transplant recipients. For specimens stored at -70 C for less than four months, the dot hybridization assay had a sensitivity of 90% and a specificity of 98% when compared with the lymphocyte transformation assay. The dot hybridization assay is a rapid, sensitive, and specific test that can be performed on readily available clinical specimens.
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Diaz-Mitoma F, Benningen G, Slutchuk M, Ronald AR, Brunham RC. Etiology of nonvesicular genital ulcers in Winnipeg. Sex Transm Dis 1987; 14:33-6. [PMID: 3494322 DOI: 10.1097/00007435-198701000-00007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Twenty-eight patients with recent onset of nonvesicular ulcerative genital lesions were studied prospectively to define the microbial etiology. Causative agents identified included herpes simplex virus (HSV), Chlamydia trachomatis, Haemophilus ducreyi, and Treponema pallidum. Three women and 25 men (seven of whom were homosexual) were studied. Ten patients did not have an etiology identified. Nine patients had syphilis, six had genital herpes, one had chancroid, one had granuloma inguinale, and one had a human bite injury. Six of seven homosexual men had syphilis, as compared with one of eight heterosexual men (P less than .002). Among heterosexual men, five had atypical HSV infections, three with extensive balanoposthitis and two with chancroidal ulcers. Of the clinical characteristics examined, induration of the ulcer base and tenderness on palpation were predictive of etiology, whereas numbers of ulcers and regional lymphadenopathy were not. H. ducreyi was not a common cause of genital ulcers in Winnipeg, and it was not found as a commensal or superinfecting organism in ulcers caused by other agents.
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Diaz-Mitoma F, Harding GK, Louie TJ, Thomson M, James M, Ronald AR. Prospective randomized comparison of imipenem/cilastatin and cefotaxime for treatment of lung, soft tissue, and renal infections. REVIEWS OF INFECTIOUS DISEASES 1985; 7 Suppl 3:S452-7. [PMID: 3901207 DOI: 10.1093/clinids/7.supplement_3.s452] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Thirty-one moderately or severely ill hospitalized patients with proved (25 patients) or suspected (six) bacterial infections were randomly allocated to receive imipenem/cilastatin (16) or cefotaxime (15). The median age, sex, duration of therapy, underlying disease, and types of infection were similar in both groups. Nineteen patients with pneumonia, eight with soft tissue infection, and four with acute pyelonephritis were included. The pathogens isolated included Escherichia coli (six), Streptococcus pneumoniae (five), Streptococcus pyogenes (five), Haemophilus species (four), Proteus species (three), Staphylococcus aureus (three), and Serratia marcescens (two). In the imipenem/cilastatin group, 13 patients were cured of their infections and three showed improvement. In the cefotaxime group, nine were cured, three showed improvement, and three showed no improvement. Nine patients treated with imipenem/cilastatin developed phlebitis, as compared with eight treated with cefotaxime. One patient treated with cefotaxime developed diarrhea. During therapy, potential pathogens were isolated from four patients in the imipenem/cilastatin group (Candida species [two] and Pseudomonas maltophilia [two]), as compared with eight in the cefotaxime group (enterococci [two], Pseudomonas aeruginosa [two], Candida species [two], Acinetobacter anitratus [one], and Pseudomonas fluorescens [one]). There were no recognized superinfections.
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