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B Mirza

Publications and source records attributed to B Mirza.

8 recordsLinked to original sources
PubMed2005

Influence of the nature of the T-DNA insertion region on transgene expression in Arabidopsis thaliana.

In the experiment reported here, effect of the nature of T-DNA integration region on the activity of the transgenes was studied by using a colour marker gene in Arabidopsis thaliana. For this purpose a pale homozygous ch-42 mutant was transformed with the wild-type copy of the gene (CH-42) using kanamycin resistance gene as a selectable marker. Two independent lines were identified in which CH-42 transgene was inactive. The T-DNA flanking sequences were recovered from these inactive and two active lines. These flanking sequences were used to examine copy number and DNA methylation of the T-DNA insertion site in active and inactive lines. Southern blots produced by using MspI/HpaII digested genomic DNA showed signs of methylation in both inactive lines. Furthermore, in one of the inactive line the T-DNA flanking sequence probe hybridized to highly repetitive sequence. The results suggest some correlation between silencing of the transgene and methylation of its insertion region.

Arabidopsis↗
PubMed2003

Treatment of facial superficial basal cell carcinomas with imiquimod 5% cream.

Basal cell carcinoma (BCC) is the most common form of skin cancer and occurs predominantly as two forms, nodular or superficial. We report cases of two females who presented with facial BCCs, one with a 2-month history of superficial BCC with a dual growth pattern (superficial BCC overlying a deep micronodular pattern BCC), and the other with a 4-year history of superficial BCC. Both patients had undergone previous unsuccessful treatments. Differing responses of facial superficial BCCs were observed following daily treatment with imiquimod 5% cream over 6 weeks. This included a treatment failure in the BCC with a dual growth pattern and complete clearance of the other superficial BCC.

Administration, Topical↗
PubMed2003

Antimicrobial susceptibility in community-acquired bacterial pneumonia in adults.

OBJECTIVES: To determine the antimicrobial susceptibility patterns of Streptococcus pneumoniae and Haemophilus influenzae, two bacterial pathogens commonly associated with community-acquired pneumonia. DESIGN: Cross-sectional study. SETTING: Bacterial isolates were obtained from adults suspected to have community-acquired pneumonia and who sought treatment at two city council clinics in Nairobi, Kenya. Susceptibility to antimicrobial agents was performed using a microdilution broth method, according to the criteria set by the National Committee for Clinical Laboratory Standards. RESULTS: A total of 277 S. pneumoniae and 58 H. influenzae were obtained from 536 adults examined in the period January 1998 to December 1999. Of the 277 S. pneumoniae, only 56.7% were susceptible to penicillin and 7.6% of strains were resistant to two or more antimicrobial agents. Of the 58 H. influenzae strains, 91.4% were sensitive to ampicillin, with 6.8% resistant to two or more antimicrobial agents. 8.6% were beta-lactamase producers and accounted for the entire ampicillin-resistant population. CONCLUSION: The prevalence of resistance to penicillin and other commonly used antibiotics among pneumococci is high and the large number of multi-resistant strains among H. influenzae is a cause for concern. The prudent use of antibiotics in treatment of pneumonia and other infections should be advocated to minimise spread of resistance.

Adult↗
PubMed2001

Effects of immunosuppressive treatment on host responses against intracerebral porcine neural tissue xenografts in rats.

BACKGROUND: Embryonic xenogeneic neural tissue is an alternative for transplantation in Parkinson's disease, but immune responses limit the application. The aims of this study were to enhance the in vitro viability rates by donor tissue pretreatment; to compare the efficacy of cyclosporine A (CsA) and tacrolimus (FK) in inhibiting xenograft rejection in rats; to evaluate additional inductive therapy with prednisolone (PRE) or mycophenolate mofetil (MMF). METHODS: Tirilazad (a lipid peroxidase inhibitor) or FK and acYVAD-cmk (a caspase inhibitor), were added to embryonic porcine ventral mesencephalic tissue and viability was assessed in vitro. Tirilazad-treated tissue was grafted to the striatum of rats that were either left untreated or immunosuppressed with FK (1 mg/kg) or CsA (15 mg/kg) alone or in combination with a 2-week PRE (20 mg/kg) or MMF (40 mg/kg) induction course. Xenograft survival and host responses were determined using immunohistochemistry. RESULTS: Pretreatment with tirilazad enhanced tissue survival in vitro. After transplantation into untreated controls, there was no graft survival at twelve weeks. Neural cell counts were significantly improved in immunosuppressed recipients, but there were no differences between the treatment groups. Additional inductive treatment reduced the infiltration with CD4+ and CD8+ cells, and macrophage infiltration was reduced compared with animals given CsA or FK alone. CONCLUSION: Pretreatment of the donor tissue with free-radical scavengers reduces cell loss caused by tissue trauma. Porcine neural tissue xenografts survive significantly better in animals immunosuppressed with either FK or CsA. Additional inductive treatment with PRE or MMF reduced the infiltration of host cells into the xenografts.

Animals↗
PubMed2001

Porcine neural xenografts in rats and mice: donor tissue development and characteristics of rejection.

Embryonic ventral mesencephalic tissue from the pig is a potential alternative donor tissue for neural transplantation to Parkinson's disease patients. For stable graft survival, the host immune response has to be prevented. This study was performed in order to analyze the mechanisms and dynamics of neural xenograft rejection, as well as neurobiological properties of the donor tissue. Adult normal mice and rats, and cyclosporin A-treated rats, received intrastriatal transplants of dissociated embryonic ventral mesencephalic pig tissue that was 27 or 29 embryonic days of age (E27 and E29). The animals were perfused at 2, 4, 6, and 12 weeks after grafting and the brains were processed for immunohistochemistry of dopaminergic (tyrosine hydroxylase positive) neurons, CD4(+) and CD8(+) lymphocytes, natural killer cells, macrophages, microglia, and astrocytes. Thirty-five rats received daily injections of BrdU for 5 consecutive days at different time points after transplantation and were perfused at 6 weeks. These animals were analyzed for proliferation of cells in the donor tissue, both in healthy and in rejecting grafts. No tyrosine hydroxylase-positive cells proliferated after grafting. Our results demonstrated that E27 was superior to E29 donor tissue for neurobiological reasons. Cyclosporin A immunosuppression was protective only during the first weeks and failed to protect the grafts in a long-term perspective. Grafts in mice were invariably rejected between 2 and 4 weeks after transplantation, while occasional grafts in untreated rats survived up to 12 weeks without signs of an ongoing rejection process. CD8(+) lymphocytes and microglia cells are most likely important effector cells in the late, cyclosporin A-resistant rejection process.

Animals↗
PubMed2000

The absence of reactive astrocytosis is indicative of a unique inflammatory process in Parkinson's disease.

Virtually any neurological disorder leads to activation of resident microglia and invasion of blood-borne macrophages, which are accompanied by an increase in number and change in phenotype of astrocytes, a phenomenon generally termed reactive astrocytosis. One of the functions attributed to activation of astrocytes is thought to involve restoration of tissue damage. Hitherto, the role of astrocytes in the inflammatory reaction occurring in Parkinson's disease has not received much attention. In the present study, we examined the inflammatory events in autopsies of the substantia nigra and putamen from Parkinson's disease patients using age-matched autopsies from normal patients as controls. In the substantia nigra, activation of microglia was consistently observed in all Parkinson's disease autopsies as verified from immunohistochemical detection of CR3/43 and ferritin. Activation of resident microglia was not observed in the putamen. No differences were observed between controls and Parkinson's disease autopsies from the substantia nigra and putamen, in terms of distribution, cellular density or cellular morphology of astrocytes stained for glial fibrillary acidic protein or metallothioneins I and II, the latter sharing high affinity for metal ions and known to be induced in reactive astrocytes, possibly to exert anti-oxidative effects. Together, these findings indicate that the inflammatory process in Parkinson's disease is characterized by activation of resident microglia without reactive astrocytosis, suggesting that the progressive loss of dopaminergic neurons in Parkinson's disease is an ongoing neurodegenerative process with a minimum of involvement of the surrounding nervous tissue. The absence of reactive astrocytosis in Parkinson's disease contrasts what follows in virtually any other neurological disorder and may indicate that the inflammatory process in Parkinson's disease is a unique phenomenon.

Aged↗