Fourier analysis of video-keratographic data. A tool for separation of spherical, regular astigmatic and irregular astigmatic corneal power components

Topographic analysis of the cornea and computation of changes in corneal topography is difficult because of the lack of a standardized concept for analysing topographic information. We have used Fourier series harmonic analysis to decompose the often very complex information given in topographic images (TMS-1 video-keratograph). The polar data values arising from each mire were separated into spherical (average power), regular astigmatic (2′ harmonic) and non-regular astigmatic components. The non-regular astigmatic components were further divided into a decentration component (1′ harmonic) and a higher order irregular refractive component (root mean square (r.m.s.) of the residual between original data and the sum of spherical, 1′ and 2′ order components). Algorithms for utilizing the Fourier analysis technique on subjective refractive and on keratometric changes in regular astigmatism were also derived. Averages of the separate refractive components were calculated for groups of normal (right and left eye of 25 patients), keratoconic (13 eyes), and transplanted eyes (20 eyes), and average topographic maps were reconstructed and imaged. Changes in the separate topographic refractive components were compared with subjective refractive changes in eyes that had undergone combined myopic-astigmatic excimer laser ablation (8 eyes). Fourier series analysis was found superior to conventional keratometry in predicting spherical and regular astigmatic changes in subjective refraction. Fourier series analysis seems to be a powerful tool to decompose the information of complex topographic corneal images into rational optical components.     

VerstÄrkung der radiotherapeutischen wirkung auf HeLa-Zellen durch gemcitabine

BACKGROUND: Gemcitabine (2'.2'-difluorodeoxycytidine; dFdC) is a new nucleoside analog with promising activity in different solid tumors in vivo and in vitro. As published up to now, combined with irradiation dFdC demonstrates a radiosensitizing effect on pancreas and colon carcinoma cell lines. We investigated the influence of dFdC on the radiosensitization of human squamous carcinoma cells of the cervix (HeLa-cells, ATCC CCL-2). MATERIAL AND METHODS: Under standardized conditions monolayer cultures of HeLa-cells were incubated in medium with dFdC for different times (4 to 24 hours) and exposed to different concentrations (0.003, 0.01 and 0.03 mumol/l). Irradiation (2 to 6 Gy, electron beam) followed immediately or 12 hours after dFdC-exposure. Cell survival was determined by colony forming assay. Using the linear-quadratic model cell survival curves were fit after correction for drug-induced cytotoxicity and the mean inactivation dose (MID) was calculated. Radiation enhancement was defined as the ratio MIDRT(= Control)/MIDRT + dFdC > 1. RESULTS: Exposed to gemcitabine for 4 and 8 hours and followed by immediate irradiation the radiation enhancement ratio (Table 1) is 1.07 to 1.14 and 1.04 to 1.22, respectively, if dFdC concentration is > or = 0.01 to 0.03 mumol/l. Further increase of the irradiation effect is demonstrated in cells exposed to > or = 0.003 to 0.03 mumol/l dFdC for 16 and 24 hours (radiation enhancement ratio 1.08 to 2.0 and 1.08 to 2.48, respectively) (Figure 3). If irradiation is applied 12 hours after 24-hour-exposure (0.01 and 0.03 mumol/l) the enhancement ratio was 1.18 and 1.7, respectively (Figure 4). CONCLUSIONS: In cell cultures the assays combining irradiation with dFdC demonstrate that dFdC is a potent radiation sensitizer of HeLa-cells. The effect of irradiation on cells pre-treated with non- and hardly cytotoxic concentrations of dFdC is increased in dependence of dose and time of exposure.     

Are psychotic symptoms related to vagus nerve stimulation in epilepsy patients?

Four patients with refractory epilepsy presented with psychotic symptoms following treatment with vagus nerve stimulation (VNS) to control seizures. Besides its anti-epileptic effect VNS has been shown to have an effect on various cognitive and behavioural functions. VNS is known to increase alertness and reduce sedation, which is independent from seizure control. VNS has also been shown to positively affect cognition and to exert strong antidepressant effects. Co-morbidity in epilepsy often comprises psychiatric illnesses. Increased psychiatric symptoms have mainly been described in association with successful outcome following epilepsy surgery as a result of 'forced normalisation'. Different hypotheses on the underlying aetiology of VNS-induced psychotic symptoms other than the previously described 'forced normalisation' are discussed.     

Maternal fish oil supplementation in lactation and growth during the first 2.5 years of life

Fish oil addition to infant formulas has raised concern on whether increased intake of n-3 long-chain polyunsaturated fatty acid (n-3LCPUFA) affects infant growth. The objective of this study was to determine whether maternal fish oil supplementation during 0-4 mo of lactation influences growth in infancy and early childhood. In a randomized, blinded intervention trial, lactating Danish mothers with a fish intake below the population median were randomized to 4.5 g/d fish oil or olive oil. A reference group of 53 mothers with a fish intake in the highest quartile of the population and their infants were included in the study. Head circumference, weight, length, skinfold thickness, and waist circumference of children were measured at 2, 4, and 9 mo and at 2.5 y. One hundred children completed the intervention trial, and 72 were followed up at 2.5 y together with 29 from the reference group. Growth in weight, length, and head circumference did not differ between the randomized groups up to 9 mo, but at 2.5 y, body composition differed significantly. Children in the fish oil group had larger waist circumference body mass index (BMI; 0.6 kg/m(2); p = 0.022), and head circumference compared with those in the olive oil group. Adjusted for sex, ponderal index at birth and current energy intake, BMI at 2.5 y was associated with docosahexaenoic acid in maternal erythrocytes after the intervention. In conclusion, the n-3LCPUFA intake of lactating mothers may be important for growth of young children. The long-term effect on weight and BMI remains to be investigated.     

Sagittal abdominal diameter and waist circumference appear to be equally good as identifiers of cardiometabolic risk

Background and aimsBody mass index (BMI) and waist circumference (WC) are commonly used markers of cardiometabolic risk. However, sagittal abdominal diameter (SAD) has been proposed as a possibly more sensitive marker of intra-abdominal obesity. We investigated differences in how SAD, WC, and BMI were correlated with cardiometabolic risk markers.Methods and resultsThis cross-sectional study investigated anthropometric and metabolic baseline measurements of individuals from six trials. Multiple linear regression and (partial) correlation coefficients were used to investigate associations between SAD, WC, and BMI and cardiometabolic risk markers, including components of the metabolic syndrome as well as insulin resistance, blood lipids, and lowgrade inflammation.In total 1516 mostly overweight or obese individuals were included in the study. SAD was significantly more correlated with TG than WC for all studies, and overall increase in correlation was 0.05 (95% CI (0.02; 0.08). SAD was significantly more correlated with the markers TG and DBP 0.11 (95% CI (0.08, 0.14)) and 0.04 (95% CI (0.006, 0.07), respectively compared to BMI across all or most studies.ConclusionThis study showed that no single anthropometric indicator was consistently more strongly correlated across all markers of cardiometabolic risk. However, SAD was significantly more strongly correlated with TG than WC and significantly more strongly correlated with DBP and TG than BMI.     

Risk-sensitive events during laparoscopic cholecystectomy: the influence of the integrated operating room and a preoperative checklist tool

Background  

Awareness of the relative high rate of adverse events in laparoscopic surgery created a need to safeguard quality and safety of performance better. Technological innovations, such as integrated operating room (OR) systems and checklists, have the potential to improve patient safety, OR efficiency, and surgical outcomes. This study was designed to investigate the influence of the integrated OR system and Pro/cheQ, a digital checklist tool, on the number and type of equipment- and instrument-related risk-sensitive events (RSE) during laparoscopic cholecystectomies.