The frequency of the extra-distal root on the mandibular first molar was 20%, and the incidence of three canals (Vertucci's type 8 classification) with separate apical foramina at the apex of the mesial root was 6%. The three-rooted variation of the mandibular first molar appears to be a genetic characteristic of an Asiatic racial background.

In addition to antidepressant drugs, some neuroleptic (NL) drugs reduce serotonin2 (5-HT2) receptor binding sites after chronic administration. The present study was undertaken to characterize further this property of NL drugs. Scatchard analysis of [3H]spiperone binding in rat cerebral cortex revealed that 21-day treatment with chlorpromazine (CPZ), cis-flupenthixol, and thioridazine reduced 5-HT2 radioligand binding density by 60, 27, and 18%, respectively. The more selective dopamine-D2 antagonists haloperidol and sulpiride were totally ineffective in this regard. No reduction in 5-HT2 ligand binding sites occurred after 1 day of treatment with CPZ but 3-days of treatment was effective and this reduction persisted, although diminished, for at least 72 h after the last injection. cis-Flupenthixol and d-butaclamol were also effective after 3 days of treatment but trans-flupenthixol and l-butaclamol were not, indicating stereo-specificity of the response mechanism. Female rats showed the same response to CPZ as did male rats. Central 5,7-dihydroxytryptamine-induced lesions of 5-HT neurons demonstrated that intact 5-HT neurons were not required for the reduction of 5-HT2 receptor ligand binding by CPZ. Since CPZ has high affinity for many receptors, including alpha 1, histamine1, and muscarinic receptors, the role of these effects in producing 5-HT2 receptor down-regulation was considered by studying the effects of prazosin, atropine, and pyrilamine administration on 5-HT2 radioligand binding. Results indicate that no one of these actions appears to account for the down-regulation of 5-HT2 receptors by CPZ. Several of these effects, in combination, or some unique mechanism, may be involved.

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Carotid artery stenosis is a narrowing or constriction of any part of the carotid arteries, usually caused by atherosclerosis. However, no studies have specifically evaluated the association between carotid atherosclerosis (CA) and chronic periodontitis (CP). This study was to investigate the role of CP in increasing the subsequent risk of CA in the overall Taiwanese population. We carried out this retrospective cohort study, employing data derived from the National Health Insurance Research Database. A total of 72,630 patients who were newly diagnosed with CP from 2001 to 2012 were selected. For a propensity-matched control group, 72,630 healthy patients without CP were picked at random, matched according to age, sex, and index year from the general population. Cox proportional hazard regression analysis, which included sex, age, and comorbidities, was adopted to assess the hazard ratio (HR) of CA between the CP cohort and non-CP cohort. The average ages of the CP and non-CP groups were 44.02 ± 14.63 years and 44.15 ± 14.41 years, respectively. The follow up durations were 8.65 and 8.59 years for CP and non-CP groups, respectively. The results demonstrated that 305 and 284 patients with newly diagnosed CA were found in the CP cohort and non-CP cohort, respectively. There was no significant difference of developing CA in the CP cohort compared with the non-CP cohort (adjusted HR) 1.01, 95% confidence interval (CI, 0.86–1.19). However, multivariate Cox regression analysis indicated that the male group had significantly higher incidence risk of CA (log rank p = 0.046). In conclusion, this nationwide retrospective cohort study indicated that male patients with CP exhibited a significantly higher risk of CA than those without CP.

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