The quality of systematic reviews of health-related outcome measurement instruments.

BACKGROUND: Systematic reviews of outcome measurement instruments are important tools for the selection of instruments for research and clinical practice. Our aim was to assess the quality of systematic reviews of health-related outcome measurement instruments and to determine whether the quality has improved since our previous study in 2007. METHODS: A systematic literature search was performed in MEDLINE and EMBASE between July 1, 2013, and June 19, 2014. The quality of the reviews was rated using a study-specific checklist. RESULTS: A total of 102 reviews were included. In many reviews the search strategy was considered not comprehensive; in only 59 % of the reviews a search was performed in EMBASE and in about half of the reviews there was doubt about the comprehensiveness of the search terms used for type of measurement instruments and measurement properties. In 41 % of the reviews, compared to 30 % in our previous study, the methodological quality of the included studies was assessed. In 58 %, compared to 55 %, the quality of the included instruments was assessed. In 42 %, compared to 7 %, a data synthesis was performed in which the results from multiple studies on the same instrument were somehow combined. CONCLUSION: Despite a clear improvement in the quality of systematic reviews of outcome measurement instruments in comparison with our previous study in 2007, there is still room for improvement with regard to the search strategy, and especially the quality assessment of the included studies and the included instruments, and the data synthesis.

Sample stimulus control shaping and restricted stimulus control in capuchin monkeys: a methodological note.

This paper reports use of sample stimulus control shaping procedures to teach arbitrary matching-to-sample to 2 capuchin monkeys (Cebus apella). The procedures started with identity matching-to-sample. During shaping, stimulus features of the sample were altered gradually, rendering samples and comparisons increasingly physically dissimilar. The objective was to transform identity matching into arbitrary matching (i.e., matching not based on common physical features of the sample and comparison stimuli). Experiment 1 used a two-comparison procedure. The shaping procedure was ultimately effective, but occasional high error rates at certain program steps inspired a follow-up study. Experiment 2 used the same basic approach, but with a three-comparison matching task. During shaping, the monkey performed accurately until the final steps of the program. Subsequent experimentation tested the hypothesis that the decrease in accuracy was due to restricted stimulus control by sample stimulus features that had not yet been changed in the shaping program. Results were consistent with this hypothesis, thus suggesting a new approach that may transform the sample stimulus control shaping procedure from a sometimes useful laboratory tool to a more general approach to teaching the first instance of arbitrary matching performances to participants who show protracted difficulties in learning such performances.

Hormonal and metabolic characteristics of genetically obese Zucker and dietary obese Sprague-Dawley rats.

The endocrine-metabolic plasma pattern and the capacity of isolated perfused livers to produce triglycerides and ketone bodies have been studied in genetically and diet-acquired obese rats (Zucker and Sprague-Dawley obese rats), and in control groups of the same strains. An increased plasma insulin/glucagon molar ratio with hyperinsulinaemia and hypoglucagonaemia was associated with hypertriglyceridaemia, normal ketonaemia, elevated free fatty acids and normal or slight hyperglycaemia in obese rats. During oleate perfusion, the livers of Zucker and Sprague-Dawley obese rats showed an increase in triglyceride output and liver triglyceride content. The ketone body output as well as the mitocondrial carnitine palmitoyl transferase activity were normal or slightly decreased. In our rat population, a positive correlation between the insulin/glucagon molar ratio and triglyceride output has been found.

Glucagon and insulin secretion in potential diabetes.

Insulin and glucagon have been studied in 20 subjects (both of the subjects' parents were diabetic or in case of only one diabetic parent, the other showed a first degree familiarity of diabetes): 10 showed normal glucose tolerance ('true prediabetics') and 10 impaired glucose tolerance ('genetic chemical diabetes'). Mean insulin response to oral (100 g) and i.v. glucose load (200 mg/kg followed by 20 mg/kg/min for 60 min) and to arginine infusion (25 g in 30 min) was normal in the prediabetics and delayed and higher in the subjects with chemical diabetes as compared to the control group. Glucagon response to arginine was higher, but not significantly, in prediabetics and in subjects with chemical diabetes. In both of these groups glucagon suppression by glucose was not observed. The insulin/glucagon molar ratio was significantly reduced after glucose infusion in these two groups. No correlation was found between insulin and glucagon secretion after arginine or glucose. A possible alteration in the mechanism controlling glucagon secretion even in the earliest phases of diabetes is suggested.

Hypolipidemic effects of metformin in hyperprebetalipoproteinemia.

Metformin's hypolipidemic effects (2.55 g/day for 3 months) have been studied in 19 subjects with Fredrickson's Type IV hyperprebetalipoproteinemia. The majority of patients were above ideal body weight (relative body weight = 118 +/- 2.7 %). Eleven of the subjects presented chemical diabetes, 5 fasting hyperglycemia, and 3 normal glucose tolerance. After treatment with metformin, body weight showed a slight, but significant reduction (--2.4 +/- 0.3 kg). Glucose tolerence was not substantially altered while basal glucose was significantly reduced in the 5 subjects with fasting hyperglycemia. Basal plasma insulin was significantly reduced in all the patients following metformin treatment. Insulin response to OGTT was slightly reduced in the subjects with fasting hyperglycemia. Independent of the patients' glucose tolerance, metformin treatment induced a marked decrease in plasma triglycerides (-- 40 %) and a reduction in plasma cholesterol (-- 12 %). No correlation was found between triglyceride and cholesterol reduction and body weight, glucose, and plasma insulin variations. Like phenformin, metformin acts not only on glucose metabolism and insulin secretion but on lipid metabolism as well.