Synthesis and polymerization of fluorinated acrylic monomers substituted in α-position, 2. Synthesis and polymerization of 2-perfluorohexylethyl α-acetoxyacrylate

The synthesis of 2-perfluorohexylethyl α-acetoxyacrylate (^b) H₂C?C(OAc)CO₂C₂H₄C₆F₁₃ ( 1 ) was performed in two steps starting from pyruvic acid and 2-perfluorohexylethanol (3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanol) with an overall yield of about 50%. Esterification of pyruvic acid with the adequate fluorinated alcohol was followed by enol acetylation to give monomer 1 . Homopolymerization and copolymerization of 1 are easily carried out. From the kinetic study of the homopolymerization and copolymerization of 1 with styrene, the numerical values of the ratio square of the rate constant of propagation over the rate constant of termination k/k_t and of the copolymerization reactivity ratios r₁ and r₂ of the two monomers were determined.     

Novel mechanism of tumorigenesis: increased transforming growth factor-beta 1 suppresses the expression of connexin 43 in BALB/cJ mice after implantation of poly-L-lactic acid

Poly-L-lactic acid (PLLA) is a widely used promising material for surgical implants such as tissue-engineered scaffolds. In this study, we aimed to determine the in vivo effect of PLLA plates on the cellular function of subcutaneous tissue in the two mouse strains, BALB/cJ and SJL/J, higher and lower tumorigenic strains, respectively. Gap-junctional intercellular communication (GJIC) and the expression of connexin 43 (Cx43) protein were significantly suppressed, whereas the secretion of transforming growth factor-beta 1 (TGF-beta 1) level was significantly increased in PLLA-implanted BALB/cJ mice compared with BALB/cJ controls. However, no significant difference in TGF-beta 1 secretion was observed between the SJL/J-implanted and SJL/J control mice. We found for the first time that a significant difference was observed between the two strains; thus, the PLLA increased the secretion of TGF-beta 1 and suppressed the mRNA expression of Cx43 at the earlier stage after implantation into the higher-tumorigenic strain, BALB/cJ mice. This novel mechanism might have a vital role in the inhibition of GJIC and promote the tumorigenesis in BALB/cJ mice.     

Analysis of MHC genes in a Tunisian isolate with autoimmune thyroid diseases: implication of TNF -308 gene polymorphism

Autoimmune thyroid diseases (AITDs), which include Hashimoto thyroiditis (HT), Graves' disease (GD) and primary idiopathic myxoedema (PIM), are recognized as multifactorial diseases. In this study, we have examined single and haplotypic genetic variation across the major histocompatibility complex (MHC) in a Tunisian isolate with a high prevalence of AITDs (62 patients: 32 with GD, 9 with HT and 21 with PIM). Genotyping was performed for HLA class I and II alleles as well as polymorphisms within tumor necrosis factor (TNF), lymphotoxin alpha (TLalpha) and heat shock protein (HSP70-02 and HSP70-hom) genes. Our results showed association of HLA-A2-B50-TNF 2 haplotype with AITDs (p = 0.045). Linkage analysis using Simwalk2 program has shown significant result with TNF -308 gene polymorphism (p = 0.03). The FBAT has given evidence for genetic association with TNF -308 and HLA-DR gene polymorphisms. TNF 2 allele was associated with GD (p = 0.0011), whereas TNF 1, HLA-DR11 and DR12 (p = 0.0039, p = 0.00089 and p = 0.0056, respectively) were rather implicated in HT pathogenesis. Results found by TDT-STDT have confirmed the involvement of the TNF -308 gene polymorphism in AITD pathogenesis (p < 10(-9)).     

Heligmosomoides polygyrus inhibits established colitis in IL-10-deficient mice

Inflammatory bowel disease (IBD) is prevalent in industrialized countries, but rare in less-developed countries. Helminths, common in less-developed countries, may induce immunoregulatory circuits protective against IBD. IL-10(-/-) mice given piroxicam develop severe and persistent colitis. Lamina propria mononuclear cells from colitic IL-10(-/-) mice released IFN-gamma and IL-12. The ongoing piroxicam-induced colitis could be partially blocked with anti-IL-12 monoclonal antibody suggesting that the inflammation was at least partly IL-12 dependent. Colonization of piroxicam-treated colitic IL-10(-/-) mice with Heligmosomoides polygyrus (an intestinal helminth) suppressed established inflammation and inhibited mucosal IL-12 and IFN-gamma production. H. polygyrus augmented mucosal IL-13, but not IL-4 or IL-5 production. Transfer of mesenteric lymph node (MLN) T cells from IL-10(-/-) animals harboring H. polygyrus into colitic IL-10(-/-) recipients inhibited colitis. MLN T cells from worm-free mice did not. Foxp3 (scurfin) drives regulatory T cell function. H. polygyrus enhanced Foxp3 mRNA expression in MLN T cells that had regulatory activity. This suggests that H. polygyrus inhibits ongoing IL-10(-/-) colitis in part through blocking mucosal Th1 cytokine production. Resolution of inflammation is associated with increased IL-13 production and can be adoptively transferred by MLN T cells.     

Increased Levels of Inflammatory Mediators in Children and Adults Infected with Vibrio cholerae O1 and O139

Investigations were carried out to study the production of factors associated with the innate immune response in the systemic and mucosal compartments in adults and children infected with Vibrio cholerae O1 and V. cholerae O139. The levels of nonspecific mediators of the innate defense system, i.e., prostaglandin E₂ (PGE₂), leukotriene B₄ (LTB₄), and lactoferrin (Lf), as well as myeloperoxidase (MPO), were elevated at the acute stage of the disease in stools obtained from both O1- and O139-infected adults and children. In the systemic compartment, the levels of Lf were increased after onset of disease, which in children remained elevated up to convalescence compared to the healthy controls. Increased concentrations of C-reactive protein were seen in the sera of adult cholera patients at the acute stage of infection. Elevated levels of the nitric oxide (NO^·) metabolites (nitrite and nitrate [NO₂⁻ and NO₃⁻]) were detected in plasma but not in urine. The activity of the scavenger of reactive oxygen species, superoxide dismutase, was higher in the plasma of adults immediately after the onset of disease, suggesting that an active scavenging of reactive oxygen species was taking place. The concentration of 8-iso-prostaglandin F_2α remained unchanged in the systemic and mucosal compartments in the study subjects. After the recovery of patients from cholera, the concentration of the majority of the metabolites decreased to baseline levels by day 30 after the onset of infection. Immunohistochemical staining showed increased tissue expression of MPO, Lf, and inducible nitric oxide synthase at the acute stage in the duodenal biopsies of adults and rectal biopsies obtained from children with cholera. Very little difference was seen in the levels of the different inflammatory mediators in patients infected with V. cholerae O1 or the encapsulated V. cholerae O139. In summary, these results suggest that elevated concentrations of Lf, MPO, PGE₂, LTB₄, and NO^·, as well as other metabolites, during the acute stage of the disease indicate that the innate defense system, as well as the inflammatory process, is activated in both adults and pediatric patients infected with V. cholerae O1 and O139.     

Analysis of genomic downsizing on the basis of region-of-difference polymorphism profiling of Mycobacterium tuberculosis patient isolates reveals geographic partitioning

Mycobacterium tuberculosis, the etiological agent of tuberculosis, has lost many coding and noncoding regions in its genome during the course of evolution. We performed region-of-difference (RD) analysis using PCR-based genotyping of 131 M. tuberculosis clinical isolates obtained from four different countries, namely, India, Peru, Libya, and Angola. Our studies revealed that RD patterns are often distinct for strains circulating in specific geographical regions and can be used to trace the descent and spread of an isolate from its original reservoir. We describe our findings, which show that no single isolate from the four countries (n = 131) had all the 15 RDs either deleted or retained. Tuberculosis-specific deletion 1 (TbD1) was found to be conserved in 23% of the Indian isolates, indicating their possible ancient origin. RD9 was the most conserved region, RD11 was predominantly deleted, and RD6 was the most variable among the isolates in our collection irrespective of their geographic region. In contrast to earlier reports, our results demonstrate that the deletion of RD1 does not correlate with a decrease in the virulence potential of M. tuberculosis, as Indian isolates (n = 30) examined by us were from diseased individuals and yet had lost the RD1 region. Our results further illustrated that the intactness of the RD5 region may be associated with increased virulence of the organism. This study highlights that the RDs in M. tuberculosis genomes are geographically distributed and specific and may possibly be associated with virulence spectrum.     

Genotypic analysis of Mycobacterium tuberculosis in Bangladesh and prevalence of the Beijing strain

Genotypic analysis was performed on 48 Mycobacterium tuberculosis complex strains collected from a hospital in Dhaka city. Deletion analysis showed that the isolates were all M. tuberculosis; 13 of them were found to be of the "ancestral" type, while 35 were of the "modern" type, indicating that both endemic (ancestral type) and epidemic (modern type) strains cause tuberculosis in Bangladesh. Genotyping based on the spoligotype and variable-number tandem repeats (VNTR) of mycobacterial interspersed repetitive units (MIRU) was also done. A total of 34 strains (71%) were grouped by spoligotyping into nine different clusters; the largest comprised 15 isolates of the Beijing genotype, whereas the remaining eight clusters consisted of two to five isolates. MIRU-VNTR typing detected 32 different patterns among 44 tested strains, and the 15 Beijing strains were further discriminated by MIRU-VNTR typing (7 distinct patterns for the 15 isolates). These results indicate that MIRU-VNTR typing, along with spoligotyping and deletion analysis, can be used effectively for molecular epidemiological studies to determine ongoing transmission clusters; to our knowledge, this is the first report about the type of strains prevailing in Bangladesh.     

Serotypes of Streptococcus pneumoniae causing invasive childhood infections in Bangladesh, 1992 to 1995.

One hundred sixty-five invasive Streptococcus pneumoniae strains were isolated from children under five at Dhaka Shishu (Children's) Hospital during the period 1992 to 1995. Ninety-four strains were from cerebrospinal fluid, and 71 were from blood. More than 91% of the strains were isolated from patients aged 24 months or less. Predominant serotypes were, in descending order 7F, 12F, 14, 15B, 18, 5, and 22A. These comprised 70% of all isolates. The marked differences in serotype distribution in different countries indicate the need for a sentinel surveillance study for the countries of South Asia, particularly Bangladesh, China, India, and Pakistan.     

Pemphigus vulgaris: the role of IL-1 and IL-1 receptor antagonist in pathogenesis and effects of intravenous immunoglobulin on their production

Intravenous immunoglobulin (IVIG) is increasingly being used for the treatment of autoimmune diseases. In the present report, the role of IVIG on in vivo and in vitro production of IL-1 and IL-1 receptor antagonist (Ra) was studied in patients with pemphigus vulgaris (PV). Serum samples from 20 untreated patients with active PV prior to initiation of systemic therapy, 20 patients receiving IVIG treatment, 20 patients in clinical remission after conventional therapy, and 20 normal human controls were studied to determine the serum levels of IL-1alpha, IL-1beta, and IL-1Ra. The in vitro production of these cytokines was measured in the culture supernatant of peripheral blood mononuclear cells (PBMC) from 10 PV patients immediately before and after IVIG therapy and from age and sex-matched 10 healthy donors simultaneously. Elevated levels of IL-1alpha and IL-1beta were detected (i) in the serum of untreated PV patients with active disease prior to systemic therapy and (ii) before IVIG infusions in patients receiving IVIG therapy. These increased levels are statistically significant when compared to the levels in healthy controls (P < 0.01). A marked reduction of IL-1alpha and IL-1beta was detected (i) in the serum of patients in prolonged clinical remission and (ii) immediately after IVIG infusion in those patients on IVIG therapy. Increased level of IL-1Ra was detected in PV patients in prolonged clinical remission and after IVIG infusion in those receiving IVIG therapy. These differences were statistically significant when compared to the levels in normal controls and to the levels in the sera of patients with active disease (P < 0.01) or just before the beginning of IVIG infusion (P < 0.01). Similar differences in the levels of IL-1alpha, IL-1beta, and IL-1Ra were found in the culture supernatant of PBMC isolated from the PV patients pre and post IVIG therapy. These observations suggests that, compared to normal controls, patients with active PV have reversed levels of IL-1alpha, IL-1beta, and IL-1Ra. IVIG therapy may down-regulate production of IL-1alpha and IL-1beta and enhance production of IL-1Ra, in vivo and in vitro. This might be one of the important mechanisms by which IVIG produces its early therapeutic effects in pemphigus vulgaris.     

Use of PCR for Diagnosis of Post-Kala-Azar Dermal Leishmaniasis

Microscopy and PCR were compared for use in the diagnosis of post-kala-azar dermal leishmaniasis (PKDL) in 63 patients. Aspirates of lymph nodes (samples from 52 patients), skin (23 samples), and bone marrow (18 samples) were used. For 11 patients lymph node aspiration could be repeated 6 months after they recovered from PKDL. During active PKDL, PCR was positive for 42 of 52 (80.8%) lymph node aspirates and 19 of 23 (82.7%) skin aspirates, whereas microscopy was positive for only 9 of 52 (17.3%) lymph node aspirates and 7 of 23 (30.4%) skin aspirates. PCR was always positive when parasites were seen by microscopy. When the results obtained with lymph node and skin aspirates from the same patient (n = 16) were compared, there was complete agreement. Bone marrow samples were negative by microscopy and PCR for 16 patients and positive by both methods for 1 patient; for one sample only the PCR was positive. PCR confirmed the co-occurrence of visceral leishmaniasis and PKDL in one patient and confirmed the suspicion of this co-occurrence in the other patient. After recovery, no parasites were found by microscopy, but 2 of 11 (18.2%) samples were still positive by PCR. Thirty negative controls were all found to be PCR negative, and 15 positive controls were all PCR positive. Cross-reactions with Mycobacterium leprae could be ruled out. In conclusion, PCR with inguinal lymph node or skin aspirates is suitable for confirming the clinical diagnosis of PKDL. In some patients, lymph node aspirates are probably preferred because aspiration of material from the skin may leave scars.