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Natalie Ives

Publications and source records attributed to Natalie Ives.

7 recordsLinked to original sources
PubMed2004

High rates of clustering of strains causing tuberculosis in Harare, Zimbabwe: a molecular epidemiological study.

We examined the pattern of tuberculosis (TB) transmission (i.e., reactivation versus recent transmission) and the impact of human immunodeficiency virus (HIV) infection in Harare, Zimbabwe. Consecutive adult smear-positive pulmonary TB patients presenting to an urban hospital in Harare were enrolled. A detailed epidemiological questionnaire was completed, and tests for HIV type 1 and CD4 cell counts were performed for each patient. Molecular fingerprinting of the genomic DNA recovered from cultures of sputum was performed by two molecular typing methods: spacer oligonucleotide typing (spoligotyping) and analysis of variable number of tandem DNA repeats (VNTRs). A cluster was defined as isolates from two or more patients that shared the same spoligotype pattern or the same VNTR pattern, or both. DNA suitable for typing was recovered from 224 patients. The prevalence of HIV infection was 79%. Of 187 patient isolates (78.6%) typed by both spoligotyping and analysis of VNTRs, 147 were identified as part of a cluster by both methods. By spoligotyping alone, 84.1% of patient isolates were grouped into 20 clusters. The cluster size was generally <8 patient isolates, although three large clusters comprised 68, 25, and 23 patient isolates. A total of 89.4% of the patient isolates grouped into 12 clusters defined by analysis of VNTRs, with 2 large clusters consisting of 127 and 13 patient isolates, respectively. Thirty-six percent of patient isolates with a shared spoligotype and 17% with a shared VNTR pattern were geographically linked within Harare, but they were not linked on the basis of the patient's home district. In a multivariate analysis, there were no independent predictors of clustering, including HIV infection status. Comparison with the International Spoligotype database (Pasteur Institute, Pointe a Pitre, Guadeloupe) demonstrated that our three largest spoligotype clusters are well recognized and ubiquitous in Africa. In this epidemiologically well characterized urban population with a high prevalence of HIV infection, we identified a very high level of strain clustering, indicating substantial ongoing recent TB transmission. Geographic linkage could be detected in a proportion of these clusters. A small group of actively circulating strains accounted for most of the cases of TB transmission.

Adolescent↗
PubMed2003

Does adjuvant interferon-alpha for high-risk melanoma provide a worthwhile benefit? A meta-analysis of the randomised trials.

BACKGROUND: Several randomised trials have compared interferon-alpha with control as adjuvant therapy for high-risk malignant melanoma. The results of the individual trials have been either inconclusive or even apparently conflicting. To assess all the available evidence we performed a meta-analysis of these trials. METHODS: Standard methods for quantitative meta-analysis based on published data were used. Endpoints evaluated were recurrence-free survival and overall survival. A subgroup analysis by dose of interferon-alpha was performed. FINDINGS: Twelve trials, comprising 14 comparisons of interferon-alpha with control, with results available were identified. Recurrence-free survival was improved with interferon-alpha: hazard ratio 0.83, 95% confidence interval 0.77 to 0.90, p=0.000003. The benefit on overall survival was less clear (0.93, 0.85 to 1.02, p=0.1) and the confidence interval is compatible both with no benefit and with a moderate, but clinically worthwhile, benefit. There was some evidence of a dose response relationship with a significant trend for the benefit of interferon-alpha to increase with increasing dose for recurrence-free survival (test for trend: p=0.02) but not for overall survival (trend: p=0.8). INTERPRETATION: This meta-analysis provides the most reliable synthesis of the data currently available. Adjuvant interferon-alpha produces clear reductions in recurrence of high-risk melanoma, with some evidence of an effect of dose of interferon-alpha, but it is unclear whether this translates into a worthwhile survival benefit or not. Additional and more mature data are needed to resolve these issues and an individual patient data meta-analysis should be performed.

Antineoplastic Agents↗
PubMed2002

The natural history and clinical significance of intermittent viraemia in patients with initial viral suppression to < 400 copies/ml.

OBJECTIVES: To determine the prevalence and prognostic significance of intermittent viraemia (IV) in patients who attained an undetectable viral load (VL) < 400 copies/ml within 6 months on highly active antiretroviral therapy (HAART). METHODS: Retrospective analysis of viral load rebound > or = 400 copies/ml and CD4 cell counts rise for 765 patients followed for > or = 12 months following initial VL undetectability, comparing the 226 (29.5%) who maintained an undetectable VL for > 1 year from initiation of HAART and 122 (15.9%) who had one or more episodes of IV. Genotypic resistance was evaluated at the time of the first episode of IV > or = 2000 copies/ml. RESULTS: Patients with IV had a threefold higher rate of sustained virological rebound [hazards ratio (HR), 3.15; 95% confidence interval (CI), 1.72-5.77; P < 0.001). For patients with and without IV, the Kaplan-Meier estimates at 24 and 36 months after initiation of HAART were 19.3% (95% CI, 8.9-21.5) versus 7.7% (95% CI, 4.5-13.0) and 31.6% (95% CI, 21.8-44.2) versus 12.9% (95% CI, 7.5-21.5), respectively (P < 0.001). The median CD4 cell count rise at 18 and 24 months was significantly lower in those with IV than in those without: 138 [interquartile range (IQR), 58-221] versus 224 x 10(6) cells/l (IQR, 119-357) (P = 0.0001) and 200 (IQR, 89-294) versus 260 x 10(6) cells/l (IQR, 125-384) (P = 0.003), respectively. In a subgroup of 16 patients, genotypic resistance mutations were found in the reverse transcriptase gene for five (31%) and in the protease gene in one. A probable contributing factor/event was identified for most patients with IV, such as poor adherence (42.6%), intercurrent infection (26.2%) or drug interaction (6.8%). CONCLUSIONS: Patients with IV > 400 copies/ml are three times more likely to experience sustained viral rebound and to have an impaired CD4 cell rise relative to those who maintain undetectable VL. This supports the adoption of a more pro-active approach to treatment intensification and the need for caution with structured treatment interruptions.

Adult↗