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The learning context, consisting of the school children's families, teachers, and peers, has effect on their mathematics learning. The concern of students' socioeconomic status (SES) affecting negatively their learning outcomes is increasing worldwide. This study investigates whether Finnish elementary school students' SES affects their mathematical competence and success expectancy on individual and class levels. Additionally, the role of teachers' beliefs on mathematics learning and class composition on the mathematics competence and success expectancy on the class level is explored. To analyze the nested data from student questionnaires and mathematics tests, and their teachers' questionnaires, we used multilevel structural equation modelling with two levels (1, individual; 2, class). The results indicate that on the individual level, the gender and SES affect students' mathematical competence and success expectancy in mathematics. On the class level, the teacher's evaluations of academic class composition predicted students' mathematical competence, and the teachers' constructivist beliefs of mathematics learning and class composition regarding students' special needs predicted students' success expectancy. We conclude that students with disadvantaged SES need support on success expectancy to flourish in mathematics. On the class level, this support can be conveyed through teachers' constructivist pedagogical beliefs.

Effect of food on absorption of erythromycin acistrate (2'-acetyl erythromycin stearate, Erasis; CAS 96128-89-1) was studied in 14 healthy volunteers in a randomized cross-over design. The subjects were given 400 mg erythromycin acistrate enteric coated tablets b.i.d. for 4 days. On the 1st and 4th days the tablets were taken after an overnight fast or immediately after a light or a heavy breakfast. Erythromycin (E), 2'-acetyl-erythromycin (2AE), anhydroerythromycin and anhydro-2'-acetyl-erythromycin concentrations in plasma were analyzed chemically by HPLC. After a single dose the lag time of absorption (tlag) was significantly longer after both types of breakfasts as compared to fast. The tmax of E and 2AE were also somewhat delayed by food although tmax of 2AE after a heavy breakfast only differed statistically significantly from that of the fasting state. Food significantly delayed the absorption especially in some subjects since no drug was observed during the 12-h observation period in 2 and 5 of the subjects after a light and heavy breakfast, respectively. At steady state the delaying effect of food on absorption had almost disappeared. No significant differences were observed in Cmax- or AUC0-12-values between the fasting and the fed states both after a single dose or at steady state. It is concluded, that food does not affect the mean bioavailability of erythromycin acistrate neither the mean rate of absorption but in some subjects the absorption from enteric coated tablets might be significantly delayed.

The pharmacokinetics and effect of a slow-release and a conventional diltiazem tablet on atrioventricular conduction were compared in a randomized cross-over study after a single dose and at steady state in 12 healthy volunteers. The time to peak concentration was significantly delayed after the slow-release as compared to the conventional tablet, both after a single dose (2.7 vs. 0.9 h) and at steady-state (1.9 vs. 0.9 h). The peak concentration was also significantly reduced. There was no marked loss in bioavailability with the slow-release formulation. The maximal fluctuations in serum diltiazem at steady-state for the slow-release tablet were markedly less than after the conventional tablet (62 vs 87%). The PQ-interval was longer after the conventional tablet as compared to the slow-release tablet (both in doses of 120 mg) after a single dose (187 vs 163 ms) and at steady-state (197 vs 174 ms). The maximal prolongation was seen 1 h after intake of the drug. Heart rate was decreased only by 6-9 beats/min, irrespective of the dose. Slow-release diltiazem appears to have many advantages over a conventional tablet.

The excretion routes of intact metronidazole and tinidazole were studied in rats kept in metabolism cages and cannulated for continuous bile collection. The nitroimidazoles were given intraarterially either alone or after a 5-day pretreatment with phenobarbitone (70 mg/kg/day intravenously) or after a single dose of cimetidine (50 mg/kg intraarterially). After 30 mg/kg, 27.0% of the metronidazole dose was excreted intact in 24-hr urine and 2.2% in bile. After tinidazole, the recoveries of the intact drug in urine and bile were 48.1% and 1.7%, respectively. After 90 mg/kg, the total recoveries of both drugs were 25-28% smaller than after 30 mg/kg. Phenobarbitone pretreatment did not affect metronidazole levels in plasma but decreased tinidazole levels at 4 hrs. The 24-hr recoveries of the intact nitroimidazoles in urine were significantly reduced by phenobarbitone while the 24-hr bile recoveries were not. Cimetidine treatment enhanced both metronidazole (at 1, 2 and 3 hrs) and tinidazole (only at 1 hr) concentrations in plasma, but this shift was not reflected in the 24-hr urine recoveries of the intact nitroimidazoles. Cimetidine doubled, however, the 24-hr bile recovery of the intact tinidazole. The calculations of the apparent degree of metabolism, assuming no methodological losses, showed that phenobarbitone increased the metabolism of tinidazole by about 62% and that of metronidazole only by about 16%. The effect of a single dose of cimetidine was negligible.

Concentrations of metronidazole and tinidazole in serum and abdominal tissues were determined after a single 500-mg intravenous infusion or after a 5-day oral dosage of 500 mg three times daily in groups of 10 patients each. In the patients who got the single infusions, the concentrations in tissues (except fat) reached almost the serum levels 10 min after the infusion. At 24 h, the tinidazole concentrations in serum averaged 3.2 micrograms/ml and those of metronidazole 1.3 micrograms/ml. In the patients who got the 5-day oral dosages, the steady-state levels of tinidazole in both serum and tissues were twice as high as those of metronidazole.

The steady-state concentrations of metronidazole and tinidazole in male genital tissues were analyzed in patients subjected to elective gonadal surgery. The nitroimidazoles were administered orally at 500 mg every 8 h, beginning 5 days before the operation. Eight hours after the last dose, the concentrations of tinidazole were 24.1 +/- 2.5 micrograms (mean +/- standard error of the mean)/g of prostatic tissue, 29.1 +/- 2.9 micrograms/g of vas deferens, 22.1 +/- 2.1 micrograms/g of epididymis, and 18.6 +/- 2.3 micrograms/g of testis. The corresponding values of metronidazole were 14.3 +/- 1.8 micrograms/g, 15.9 +/- 1.2 micrograms/g, 14.0 +/- 1.2 micrograms/g, and 12.5 +/- 1.7 micrograms/g, respectively.

Concentrations of metronidazole and tinidazole in serum and gynecological organs were analyzed after a single 500 mg intravenous infusion and after three days of treatment with 400 mg t.i.d. of metronidazole or 500 mg b.i.d. of tinidazole. The studies were performed in 67 patients subjected to hysterectomy and/or oophorectomy because of myomatosis uteri, carcinoma uteri or endometriosis. At the time of organ removal (about 30 min after infusion), metronidazole and tinidazole levels in serum were 14.5 +/- 0.45 mg/l and 12.3 +/- 0.38 mg/l, respectively. Concentrations of both drugs in the uterus and Fallopian tube were about the same as the simultaneous serum levels and concentrations in the ovaries about 55% thereof. At steady-state, the concentrations of tinidazole in serum (23.5 +/- 1.0 mg/l) were remarkably higher than those of metronidazole (13.5 +/- 0.84 mg/l) about three hours after the last oral dose. Drug concentrations in organs of the female reproductive tract were 70 to 100% those of the simultaneous serum levels.

The drug concentration in plasma, suction skin blister fluid (SBF), urine and saliva after repeated dosage of either erythromycin acistrate (EA) or enterocoated pellets of erythromycin base (EB) was studied in young healthy volunteers with a cross-over design in two separate studies. In Study I, the total drug concentration (erythromycin + 2'-acetyl erythromycin) after EA (400 mg tid) was slightly higher than the erythromycin concentration after EB (500 mg tid). The concentration of erythromycin after EA was about half of that after EB. In SBF the total antibiotic concentration after EA and erythromycin concentration after EB were 49 and 46% of the corresponding plasma concentrations, respectively. The degree of hydrolysis of 2'-acetyl erythromycin was higher in SBF (44%) than in plasma (39%). An equal proportion (7.3-7.5%) of the dose was excreted in urine after administration of both drugs. The degree of hydrolysis of 2'-acetyl erythromycin in urine was 58%. In Study II, the plasma/saliva concentration ratio ranged from 0.11 to 0.17 after EA 400 mg tid, 0.12 to 0.20 after EA 500 mg tid and 0.17 to 0.22 after EB 500 mg tid. The degree of hydrolysis of 2'-acetyl erythromycin was considerably higher in saliva (61-78%) than in plasma (27-41%). In plasma, the percentage of hydrolysis of 2'-acetyl erythromycin was inversely correlated with the concentration of acid-alpha 1-glycoprotein. The penetration of 2'-acetyl erythromycin and erythromycin into the extravascular space as evaluated from SBF and saliva levels was equal, and adequate concentrations of erythromycin were obtained for the treatment of bacterial infections.(ABSTRACT TRUNCATED AT 250 WORDS)

Young rats given ethanol chronically by gradually increasing the concentration in the drinking fluid to 17.5% reached a maximal daily consumption of 15-17 g ethanol/kg body wt., which corresponded to 35-40% of their energy intake. This chronic treatment was markedly potentiated by additional supplementation of the drinking fluid with a low dose of the alcohol dehydrogenase inhibitor 4-methylpyrazole. Rats on this regimen exhibited higher and more sustained blood ethanol levels. Consequently, more pronounced functional and metabolic tolerance developed and more frequent signs of physical dependence was observed than in rats drinking only ethanol solution. Simple provision of drinking fluid supplemented with ethanol and 4-methylpyrazole appears to provide a nutritionally adequate and easy way to produce tolerance and other chronic alcohol effects.

Concentrations of erythromycin and 2'-acetyl erythromycin were analysed in serum or plasma and tonsil tissue after repeated dosage of erythromycin acistrate (EA), a new erythromycin prodrug, in two separate studies in 61 young patients. The reference preparations were: (1) enterocoated tablets of erythromycin base (EB enterotablets, (2) erythromycin base as enterocoated pellets (EB enterocapsules) and (3) erythromycin stearate (ES). All drugs were given 500 mg tid for three days before scheduled tonsillectomy. Tonsils were removed about 3 h after intake of the last dose. Blood samples were collected at 0, 2 and 6 h and at the time of tonsillectomy. At all time points EA produced several-fold higher total drug (erythromycin + 2'-acetyl erythromycin) concentrations in serum or plasma than any of the reference preparations. Similarly, after EA the mean total antibiotic levels in tonsil tissue exceeded the erythromycin levels after the reference preparations by at least a factor of 3. Tonsil/serum or plasma ratios of the total antibiotic were quite similar with all preparations (means 38-50%). Peak erythromycin levels in circulation did not differ significantly from each other in spite of two nonabsorbers after EB enterotablets. The same was true of tonsil tissue. There were, however, 15 tonsils with undetectable erythromycin: 4/25 (16%) with EA, 5/12 (42%) with EB enterotablets, 2/12 (17%) with EB enterocapsules and 4/12 (33%) with ES. The degree of hydrolysis of 2'-acetyl erythromycin to erythromycin was 23-43% higher in tonsil tissue than in circulation.