Combined effects of the contraceptive hormones, ethinyl estradiol and levonorgestrel, on the use of place and response memory in gonadally-intact female rats

During maze navigation rats can rely on hippocampus-mediated place memory or striatum-mediated response memory. Ovarian hormones bias whether females use place or response memory to reach a reward. Here, we investigated the impact of the contraceptive hormones, ethinyl estradiol (EE) and levonorgestrel (LNG), on memory bias. A total of 63 gonadally-intact female rats were treated with either 10 μg/kg of EE alone, 20 μg/kg of LNG alone, both 10 μg/kg of EE and 20 μg/kg of LNG together, or a sesame oil injection with 5% ethanol as a vehicle control. Rats in the control condition were tested during the diestrus phase of the estrous cycle in order to control for the low circulating levels of gonadotropin and ovarian hormones that occur with oral contraceptive administration. Rats treated with LNG alone had a bias towards the use of place memory compared to diestrus phase control rats. This bias was not observed if LNG was administered in combination with EE. Rats treated with EE or EE+LNG did not have a statistically significant difference in memory bias compared to rats in the control group. These data show that synthetic hormones contained in oral contraceptives administered to females influence which cognitive strategy is predominantly used during navigation.

Progesterone rapidly alters the use of place and response memory during spatial navigation in female rats

17β-Estradiol (E2) and progesterone (P) influence place and response memory in female rats in spatial navigation tasks. Use of these memory systems is associated with the hippocampus and the dorsal striatum, respectively. Injections of E2 result in a well-established bias to use place memory, while much less is understood about the role of P. A total of 120 ovariectomized female rats were tested within a dual-solution T-maze task and treated with either low E2 (n = 24), high E2 (10 μg/kg; n = 24), or high E2 in combination with P (500 μg/kg) at three time points before testing: 15 min (n = 24), 1 h (n = 24), and 4 h (n = 24). Given alone, high E2 biases rats to the use of place memory, but this effect is reversed when P is given 1 h or 4 h before testing. This indicates that P may be playing an inhibitory role in the hippocampus during spatial tasks, which is consistent with past findings. Our findings show that P acts rapidly (within an hour) to affect performance during spatial tasks.

An objective method of assessing facial swelling in patients with dental abscesses treated with clarithromycin

AIM

The study evaluates the efficacy of a set of objective parameters for monitoring facial swelling in a group of patients treated with clarithromycin.

METHODS

Fifty consecutive patients suffering from dental abscesses (22 in the maxillary arch and 28 in the mandibular arch) were enrolled. All these patients underwent antibiotic treatment with clarithromycin in a new formulation as a single daily dose (500 mg/day for 6 days). Pain and changes in facial swelling were evaluated at baseline and each day for 6 days through subjective parameters (visual analogic scale, VAS) and objective parameters (6 different tape measurements on the skin surface above the abscess).

RESULTS

Pain and swelling recorded by patient and dentist (using VAS scores) showed statistically significant decreases (p<0.01) on days 2, 3 and 4, while no further significant variation was observed during days 4, 5 or 6. As regards the objective parameters to quantify facial swelling, the maximum dimensional change (from baseline to final values) in the mandibular arch was obtained with measurement 6 (mean value 2.27+/-0.53 cm); the maximum dimensional change in the maxillary arch was obtained with the sum of the other 5 measurements (mean value 6.34+/-4.09 cm).

CONCLUSION

The use of a single or a combination of linear measurements might provide a sensitive and reproducible method to evaluate facial swelling objectively and could be very useful in monitoring the efficacy of new antibiotics and to compare the results from different studies.