Effectiveness of corticosteroids in otitis media with effusion: an experimental study

Objective:

The aim of the present study was to investigate the dose-related effectiveness of corticosteroids in the management of otitis media with effusion, by using the objective assessment techniques of tympanometry and cytokine measurement.

Materials and methods:

The eustachian tubes of 42 male rats were obstructed. Thirty-six subjects with effusion were randomly divided into three equal groups: controls; 0.5 mg/kg/day corticosteroid; and 1 mg/kg/day corticosteroid. Concentrations of interleukin-1β and tumour necrosis factor α in the middle-ear effusions were analysed using enzyme-linked immunosorbent assay.

Results:

An effusion occurred on the 14th post-operative day and was present on the 30th post-operative day in the control group. Otomicroscopic examination and tympanometric measurement showed an improvement in the intervention groups. There was a significant difference between both intervention groups and the control group for both interleukin-1β and tumour necrosis factor α concentrations (p < 0.01). However, there was no significant difference between the 0.5 mg/kg and the 1 mg/kg corticosteroid groups (p > 0.05).

Conclusion:

The study confirmed a short term beneficial effect of systemic steroids on resolution of otitis media with effusion in a rat model. Our results support the theory that corticosteroids significantly decrease concentrations of both interleukin-1β and tumour necrosis factor α. In our model, the 0.5 mg/kg corticosteroid dose was as effective as the 1 mg/kg corticosteroid dose. Further studies should be carried out to determine the optimal dose and duration of corticosteroids in the treatment of otitis media with effusion.

Effects of magnesium sulfate on tissue lactate and malondialdehyde levels after cerebral ischemia

In the present study, the effects of magnesium sulfate on tissue lactate and malondialdehyde (MDA) levels after cerebral ischemia in rabbits were studied. The rabbits were divided equally into three groups. Group 1 (n = 8) was the sham-operated control group, in group 2 (n = 8) only cerebral ischemia was induced by clamping bilaterally the common carotid arteries for 60 min, and in group 3 (n = 8) magnesium sulfate was administered at a dose of 100 mg/kg i.v. within 5 min after opening the clamps. In group 1 EEG recordings were obtained immediately and 60 and 120 min after craniectomy. In groups 2 and 3 EEG recordings were obtained immediately after craniectomy but before clamping and 60 min after clamping. One hour after opening the clamps and taking EEG recordings, brain cortices were resected, and the concentrations of lactate and MDA were determined using spectrophotometric/enzymatic and thiobarbituric acid methods, respectively. In all groups, there were significant differences between MDA and lactate levels (p < 0.05). There were no significant differences in lactate levels between groups 2 and 3 (p > 0.05), and also the preischemic EEG grades were the same in all groups. Preischemic and postischemic EEG values were significantly different (p < 0.05), and there were also significant differences between postischemic EEG grades in groups 2 and 3 (p < 0.05). There was a correlation between postischemic EEG grades and MDA and lactate levels. These results demonstrate that cerebral ischemia-reperfusion injury leads to an increase in brain tissue lactate and MDA levels, that magnesium sulfate suppresses the increase of MDA and lactate concentrations, and that magnesium sulfate treatment improves the EEG changes. The EEG grades correlated well with MDA and lactate levels.

Effects of deferoxamine on tissue lactate and malondialdehyde levels in cerebral ischemia

In the present study, the effects of deferoxamine on tissue lactate and malondialdehyde (MDA) levels after cerebral ischemia in rabbits was studied. Rabbits were divided equally into three groups: group 1: sham-operated group; group 2: cerebral ischemia produced by clamping bilateral common carotid arteries for 60 min; and group 3: deferoxamine 100 mg/kg i.v. administered within 5 min after opening the clamps. EEG recordings were obtained in all groups before clamping and in group 2 and 3 60 min after clamping and 60 min after opening the clamps. One hour after opening the clamps and taking EEG recordings, brain cortices were resected and the concentrations of lactate and MDA were determined using the spectrophotometric enzymatic and thiobarbituric acid methods, respectively. There were significant differences between group 1 and the other groups in MDA and lactate levels (p < 0.05). There were no significant differences in lactate levels between groups 2 and 3. Preischemic EEG grades were the same in all groups. Preischemic and postischemic EEG values were significantly different (p < 0.05), but there were no significant differences between postischemic EEG grades in groups 2 and 3. There was also a correlation between postischemic EEG grades and lactate levels, but no correlation between postischemic EEG grades and MDA levels. These results demonstrate that cerebral ischemia leads to an increase in brain tissue lactate and MDA levels and deferoxamine suppresses the increase of MDA, but not lactate. Deferoxamine treatment caused no significant EEG changes. EEG grades correlated well with lactate levels.

Effect of oral glucose loading on serum gastrin level in pregnant and non-pregnant women

AIM

To evaluate the relationship between the changes in gastrin and insulin serum concentrations after oral glucose loading in pregnant and non-pregnant women.

METHODS

Thirty women, 12 pregnant and 18 non-pregnant, with normal fasting glucose values were included in the study. Serum concentrations of gastrin, glucose, insulin, and glucagon were analyzed at 0 (t1), 30 (t2) and 60 (t3) minutes after 75 g oral glucose loading. Gastrin, insulin, and glucagon levels were determined by means of radioimmunoassay kits.

RESULTS

Serum gastrin concentration in pregnant women increased insignificantly (gastrin median values 57.91, 70.62, and 68.70 for t1, t2, and t3, respectively; Friedman's test, p = 0.264). In non-pregnant women gastrin levels insignificantly increased from t1 to t2, but reduced significantly from t2 to t3 (gastrin median values 62.91, 86.92, and 62.25 for t1, t2 and t3, respectively; Bonferroni adjusted Wilcoxon test, p = 0.002). Unlike in pregnant women, the changes in gastrin release in non-pregnant women were associated with changes in blood glucose concentrations at t2 and t3, which were induced by oral glucose loading. Glucose median values were 7.48 and 6.43 for t2 and t3, respectively. The insulin release due to the oral glucose loading markedly increased at t2 and t3 (Friedman's test, p < 0.001), whereas glucagon release decreased irrespective of pregnancy.

CONCLUSION

Changes in blood glucose concentrations induced by oral glucose loading could influence gastrin release, especially in non-pregnant women. Changes in insulin and glucagon levels induced by oral glucose loading, particularly after 60 minutes, could not be associated with changes in gastrin release.

[Serum and tissue silver levels after burns treated with silver compounds]

This study was performed in order to investigate serum and tissue silver levels in burns which were used 10 percent silver nitrate as a topical agent. We formed four groups of animals and pulverized 10 percent silver nitrate solution to the first group (GI) that included ten rabbits of which backs were burned by boiling water and silver sulphadiazine cream to second group (GII) with nine rabbits. We carried out 10 percent silver nitrate solution to the first control group (GIII) and silver sulphadiazine cream to the second control group (GIV) each of which had seven animals with unburned skin. We obtained blood samples from every animal before and after application of topical agent on the 1st, 3rd, 7th, 15th, 21st and 28th. We determined serum and tissue silver levels by atomic absorption spectrophotometer in kidney and liver of the animals which were sacrificed on the 28th day. In first and second groups we found that serum silver values reached on 3rd day to the maximum level and then the values decreased gradually. We also determined that diminution of the serum silver levels were prominent following on 15th day. It was shown that there was no silver in the serum on 28th day except four animals. The silver deposition in the liver was much more than in the kidney. Between these two groups there was significant difference neither in the serum on the same days nor the tissue silver levels. According to these data it was concluded that serum and tissue silver levels with 10 percent silver nitrate used in burns produced no difference from that of 1 percent silver sulphadiazine cream.