35. How often medical literature may be a source of incorrect clinical decision?

Change in clinical practice results mainly from positive randomized trials (superiority of tested method confirmed by significant result of statistical test). However, the rate of false positive trials might be high among all positive trials – even 30%–50%. This percentage depends mainly on the rate of trials with a real difference in efficacy between tested methods; in lesser extend it depends on a level of type II error (a number of patients in a trial). The probable high rate of false positive trials among all positive trials indicates that a risk of undertaking of incorrect clinical decision based on literature may be also high. In addition, this risk is increased due to publication bias. Therefore, confirmatory trials are often necessary. The other issue, which might be a source of incorrect clinical decision, is lack of data enabling an assessment of generalizability of trial results: 1. a number of eligible but not enrolled patients and the reasons for treatment outside trial; 2. a comparison of a characteristic of patients on trial with a characteristic of eligible, but not enrolled patients; 3. a comparison of results of treatment of patients on trial with results of treatment of eligible, but not enrolled patients 4. data of referral pattern and information on the source population, from which patients were selected

EVALUATION OF MILK PRODUCTION OF DAIRY COWS OF THE SLOVAK SPOTTED BREED ACCORDING TO SELECTION FOR LONGEVITY AND GENETIC VARIANTS OF POLYMORPHIC PROTEINS IN MILK

Elektroforetickým rozborom polymorfných bielkovín mlieka (metóda elektroforézy na škrobovom géli) 681 kráv slovenského strakatého plemena sme stanovili genetické varianty polymorfných bielkovín mlieka. Sledovali sme vplyv genetických variantov bielkovín mlieka na vybrané úžitkové vlastnosti (produkcia mlieka v kg, bielkovín v % a kg), kde rozdiely medzi testovanými skupinami boli vyhodnotené pomocou Studentovho t-testu. Pri sumárnom zhodnotení príslušných ukazovateľov úžitkovosti za produkčné obdobie medzi 25 - 162 mesiacom bol vypočítaný medzi skupinou homozygotných (AA + BB + CC genotypov) a heterozygotných genotypov (AB+AC+BC genotypov) β – kazeínu štatisticky vysoko preukazný rozdiel (+++P≤0,001, Tab. 1, 2) v produkcii mlieka o 183,7 kg a produkcii bielkovín o 7,6 kg. V polymorfizme alfa s1 – kazeín, β – laktoglobulín a κ – kazeín medzi testovanými skupinami homozygotných a heterozygotných genotypov nebol zistený preukazný rozdiel (-P≥0, 05).Milk performance of 681 cows of Slovak spotted breed was evaluated according to the genetic variants of the polymorphic proteins determined by starch gel electrophoresis. In the work the effect of genetic variants of the proteins was analysed on selected performance (production milk in kg, proteins in % and kg). Differences between the productive characters in testing groups were evaluated according to statistic method of Student ttest. Evaluation of performance was done during productive period between 25 - 162 months. The calculation between groups of homozygotes (=AA+ BB + CC genotypes) and heterozygotes (=AB+AC+BC genotypes) in the system of β – casein showed a statistically significant difference (+++P≤0,001), (table 1, 2) in milk production (183,7 kg) and proteins production (7,6 kg). In the systems of alpha s1 – casein, β – lactoglobulin and κ – casein polymorphisms, the differencies between the testing groups of homozygotes and heterozygotes were not statistically significant (-P≥0,05)