Structural MRI at 7T reveals amygdala nuclei and hippocampal subfield volumetric association with Major Depressive Disorder symptom severity.

Subcortical volumetric changes in major depressive disorder (MDD) have been purported to underlie depressive symptomology, however, the evidence to date remains inconsistent. Here, we investigated limbic volumes in MDD, utilizing high-resolution structural images to allow segmentation of the hippocampus and amygdala into their constituent substructures. Twenty-four MDD patients and twenty matched controls underwent structural MRI at 7T field strength. All participants completed the Montgomery-Asberg Depression Rating Scale (MADRS) to quantify depressive symptomology. For the MDD group, volumes of the amygdala right lateral nucleus (p = 0.05, r2 = 0.24), left cortical nucleus (p = 0.032, r2 = 0.35), left accessory basal nucleus (p = 0.04, r2 = 0.28) and bilateral corticoamygdaloid transition area (right hemisphere p = 0.032, r2 = 0.38, left hemisphere p = 0.032, r2 = 0.35) each displayed significant negative associations with MDD severity. The bilateral centrocortical (right hemisphere p = 0.032, r2 = 0.31, left hemisphere p = 0.032, r2 = 0.32) and right basolateral complexes (p = 0.05, r2 = 0.24) also displayed significant negative relationships with depressive symptoms. Using high-field strength MRI, we report the novel finding that MDD severity is consistently negatively associated with amygdala nuclei, linking volumetric reductions with worsening depressive symptoms.

Hepatitis in dental professionals.

To characterize some epidemiologic characteristics of viral hepatitis among dentists, information was obtained with a mailed questionnaire from 434 dentists and 787 attorneys in Dade County, Florida. Dentists had a significantly higher incidence of hepatitis than did lawyers, 6.7% vs 2.4%, with the highest rate among oral surgeons (21%). The incidence of hepatitis B antigenemia among asymptomatic dentists was not significantly higher than that of volunteer blood donors. Twenty-two percent of dentists with hepatitis reported treating more than ten drug addicts per year, as compared with 10% of those dentists without hepatitis. No differences were noted between dentists with and without hepatitis in methods of sterilization, the wearing of gloves during procedures, or the use of disposable needles. The increased risk of hepatitis among dentists, however, may be related to the omission of adequate prophylatic measures, particularly when treating high-risk patients such as drug abusers.