Vera Haynatzka

Long-term follow-up of primary glaucoma surgery with ahmed glaucoma valve implant versus trabeculectomy ☆

PURPOSE To compare the long-term results of trabeculectomy and Ahmed glaucoma valve implant in the initial surgical management of primary open- and closed-angle glaucoma. DESIGN Randomized controlled clinical trial. METHODS One eye each of consecutive patients with primary glaucoma and without prior intraocular surgery was randomized to receive either trabeculectomy or the Ahmed implant. Large university-affiliated eye hospital in Columbo, Sri Lanka. RESULTS Of 123 patients, 64 were randomized to trabeculectomy and 59 to the Ahmed implant. With a mean follow-up of 31 months, the trabeculectomy group had statistically lower intraocular pressures (IOP) during the first postoperative year. After the first year, the IOPs were comparable. No statistically significant differences between groups were noted for postoperative visual acuity, visual field, anterior chamber depth, and short-term or long-term complications. Adjunctive medication requirement was comparable for both groups. The cumulative probabilities of success (IOP <21 mm Hg and at least 15% reduction in IOP from preoperative levels) at the final follow-up period (months, 41-52) were 68.1% for trabeculectomy and 69.8% for Ahmed implant (P =.86). CONCLUSIONS Lower IOPs were noted for the trabeculectomy group during the first year. With longer follow-up, the IOPs and the cumulative probabilities of success were comparable between the two groups.

The determination of genetic covariances and prediction of evolutionary trajectories based on a genetic correlation matrix

There is much interest in measuring selection, quantifying evolutionary constraints, and predicting evolutionary trajectories in natural populations. For these studies, genetic (co)variances among fitness traits play a central role. We explore the conditions that determine the sign of genetic covariances and demonstrate a critical role of selection in shaping genetic covariances. In addition, we show that genetic covariance matrices rather than genetic correlation matrices should be characterized and studied in order to infer genetic basis of population differentiation and/or to predict evolutionary trajectories.

A new statistical model of tumor latency time

A new statistical parametric model of carcinogenesis is proposed. The focus is on tumor latency times. The model makes use of extreme value theory following the line initially explored by Pike [1] and further developed by Klebanov et al. [2]. In this paper, we make the first attempt to take account of the interdependence between the cells in an initiated tissue developing into a malignant tumor.

A Comparison of Statistical Approaches for Genetic Anticipation with Application to Pancreatic Cancer

Genetic anticipation for a particular disease can involve an earlier age at onset (or, diagnosis), greater severity, and/or a higher number of affected individuals in successive generations within a family. The variable of interest in our study of genetic anticipation was age at diagnosis of pancreatic cancer for different generations, with and without adjustment for time under observation. We compared nonparametric and semiparametric statistical tests for paired data. This comparison was illustrated on an example of familial pancreatic cancer where study subjects were taken from the Pancreatic Cancer Collaborative Registry (PCCR). The nonparametric test performed on our example better than the two semiparametric tests, and was more efficient in detecting risk differences at earlier ages. After adjusting for follow up time, all methods detected genetic anticipation

PCCR Study for Italy: Meat Consumption, Preparation, and Meat-Derived Carcinogens on the Risk of Sporadic Pancreatic Cancer

The objective of our hospital-based study was to identify dietary meat and preparation type factors as well as meat-derived mutagens that are associated with risk of pancreatic cancer (PC). Data collected on 99 case-control pairs matched by age, gender and region, enrolled in the international Pancreatic Cancer Collaborative Registry (PCCR), were analyzed. Conditional logistic regression produced adjusted (AOR) and unadjusted (UOR) odds ratios and 95% confidence intervals for tertiles determined from the control subjects, as well as P values for trend (Ptrend) using the medians for the tertiles. PC was associated with dietary intake of processed meat (Ptrend = 0.0495) in a non-linear fashion as well as increased intake of the mutagen MeIQX (Ptrend = 0.0444, AOR = 2.327) and, to a lesser extent, with frying (Ptrend = 0.1337) in a non-linear fashion, and the increased dietary intake of the mutagen BaP (Ptrend = 0.0687, AOR = 2.212).