Blood pressure during leg extension in children.

This study investigated blood pressure responses (BP) during bilateral leg extension in healthy children at different numbers of repetitions. BP was measured non-invasively during 1 repetition maximum (1RM), 5 repetitions at 85-90% of 1RM (5 R), 30 repetitions at 35-40% of 1RM (30 R) and during 5 s of maximal isometric work (5SM). It is important to investigate if maximal strength testing in healthy children provokes an unfavourable rise in BP, in order to be able to do further research on hypertensive risk groups of children. 39 (18 male and 21 female) healthy children (10.5 ± 2.0 years old) participated in this study. Peak BP values and peak HR increased significantly with increasing number of repetitions. Peak BP increased from 1RM (144 ± 16/110 ± 19 mmHg) to 30R (170 ± 26/123 ± 21 mmHg) and peak HR increased from 1RM (122 ± 10 bpm) to 30 R (147 ± 14 bpm). 30R also gave significantly higher BP and HR than 5SM (156 ± 24/120 ± 23 mmHg and 131 ± 16 bpm, respectively). The boys had significantly higher diastolic BP during 1RM than the girls and significantly higher BP during 5SM. In conclusion, maximal strength testing induced lower increases in BP than submaximal strength testing with more repetitions, and may be performed in healthy children within safe BP limits (< 225 mmHg in systolic BP).

[Measurement of gene activity by DNA microarrays]. / Måling av genaktivitet med DNA-mikromatriser.

BACKGROUND: DNA microarray is a tool that can be used to measure in one single analysis simultaneous changes in the activity of tens of thousands of genes. MATERIAL AND METHODS: The method is based upon advanced robotic techniques; High-density arrays of DNA probes are placed on a solid surface; this is followed by hybridisation with a fluorescence labelled sample and analysis of fluorescence signals. RESULTS: The analysis create huge data sets which have to be transformed into formats that can be interpreted and correlated with existing knowledge. This means that bioinformatics is an integrated part of microarray analysis. INTERPRETATION: DNA microarray may be used to examine complex physiological and pathological conditions and will most likely be very important in functional studies addressing the structural knowledge of genes obtained through the Human Genome Project. Dedicated microchips are already being tested in the diagnosis of malignant and premalignant diseases and being used to characterize HIV viruses with respect to choice of therapy.

Phonophobia in migraine.

Quantitative measurement of sound-induced discomfort and pain thresholds showed that migraineurs (n = 65) were significantly more sensitive than headache-free controls (n = 80), both during and outside attack (p < 0.0001). Patients tested with head pain had lower thresholds than those tested without pain (p < 0.01). Migraine with and without aura did not differ as to sound sensitivity. There were no significant differences in thresholds between the symptomatic and nonsymptomatic sides (p > or = 0.78). Patients with unilateral headache or pain of pulsating character were more sensitive than those with bilateral headache or pressing pain (p < 0.05). Phonophobia did not correlate significantly with duration, frequency, or severity of attacks. The main results were in accordance with a questionnaire study concerning subjective evaluation of sound sensitivity. Similarities between phonophobia and photophobia in migraine provide evidence that both phenomena share a common pathophysiological mechanism in this condition.

Light-induced discomfort and pain in migraine.

Quantitative thresholds for discomfort and pain with monocular and binocular light stimuli were measured in 67 controls and 67 migraine patients (37 migraine with aura and 30 migraine without aura). Patients were more photophobic during attack than outside attack (p < 0.03), and they were more sensitive to light than controls even between attacks (p < or = 0.0001). We found no differences in light sensitivity between migraine with aura and migraine without aura (p > or = 0.93). Unilateral pain affected light sensitivity on both sides. When asked with a questionnaire, 74% of patients answered that they were sensitive to light outside attack and 100% were sensitive during attack. Pain thresholds were generally lower among sensitive than non-sensitive patients (p = 0.004), indicating some agreement between subjective opinion and objective measurements of photophobia. Photophobia seems to be an intrinsic property of migraineurs. It is increased by migraine pain, but seems to be unrelated to migraine characteristics such as nausea, severity of attacks, pain character and pain laterality.

Formation of (4R)- and (4S)-4-hydroxyochratoxin A and 10-hydroxyochratoxin A from Ochratoxin A by rabbit liver microsomes.

Three metabolites were formed from ochratoxin A in the presence of rabbit liver microsomal fractions and NADPH. They were isolated by extraction, thin-layer chromatography, and high-pressure liquid chromatography. Two of them were identified as (4R)- and (4S)-4-hydroxyochratoxin A. It is suggested on the basis of mass and nuclear magnetic resonance spectroscopy that the third metabolite is 10-hydroxyochratoxin A. The formation of the metabolites was inhibited by carbon monoxide and metyrapone and was stimulated when microsomes from phenobarbital-treated animals were used. The results suggest that cytochrome P-450 catalyzes the formation of these metabolites.

Metabolism of ochratoxin A by rats.

Albino rats were given ochratoxin A (6.6 mg/kg body weight) intraperitoneally or per os. Independent of route administration, 6% of a given dose was excreted as the toxin, 1 to 1.5% as (4R)-4-hydroxyochratoxin A, and 25 to 27% as ochratoxin alpha in the urine. The metabolite (4S)-4-hydroxyochratoxin A, which is formed by rat liver microsomes in the presence of NADPH, was not detected. Only traces of ochratoxins A and alpha were found in feces. Identical experiments were carried out with brown rats, since the Km value for the formation of the 4S epimer was considerably lower when brown rat microsomes were used. About the same ratios of metabolites and metabolite recoveries as those found for albino rats were found for brown rats. Brown rats were also given the two hydroxylated metabolites and ochratoxin alpha (0.66 mg/kg body weight) intraperitoneally. The three compounds were excreted in the urine; within 48 h, 90% recovery of ochratoxin alpha and 54 and 35%, respectively, of the 4R and 4S isomers were observed.