The underlying mechanisms for the 'anti-HBc alone' serological profile.

The serological pattern, "anti-HBc alone", characterized by the presence of antibodies against the core antigen of hepatitis B virus (anti-HBc) as the only marker of hepatitis B, is not rare in a diagnostic setting. Depending on the prevalence of HBV infection and the patient group investigated, 1-31% of positive anti-HBc results are isolated positive findings. Anti-HBc alone is frequently observed in intravenous drug addicts, HIV-infected individuals, patients who are coinfected with HBV and hepatitis C virus, and pregnant women. However, it is not clear how this profile should be interpreted. Several studies have shown that anti-HBc alone is not only compatible with acute and resolved HBV infection but also with chronic infection. The reasons for the lack of HBsAg and anti-HBs in anti-HBc-alone individuals are not clear, but several mechanisms and possibilities have been suggested that could explain this phenomenon, some of which are delineated in this article.

Spinal intrathecal empyema due to Actinomyces israelii.

The authors report a case of a spinal intrathecal empyema caused by Actinomyces israelii in a patient who had been diagnosed, four years previously, of a left petrous apex abscess due to an unknown microorganism. The clinical course is outlined and the possibility of both lesions being related is discussed.

Spontaneous carotid-cavernous fistula in osteogenesis imperfecta.

A case of spontaneous carotid-cavernous fistula is presented in a patient suffering from osteogenesis imperfecta tarda type I. The patient was operated on under local anesthesia by intraluminal occlusion of the cavernous carotid artery with a Fogarty catheter, in accordance with Prolo's technique, with total remission except for homolateral loss of vision due to postglaucoma atrophy. the pathogenetic phenomena described in the literature are reviewed, with the suggestion that osteogenesis imperfecta be included with Ehlers-Danlos disease, Marfan's syndrome, and pseudoxanthoma elasticum, as a connective tissue disease with increased weakness of vessel walls that can produce a spontaneous carotid-cavernous fistula. Reports of cases operated on by intraluminal occlusion with various types of balloon-tipped catheters are also reviewed. The good results obtained place this technique among the elective ones for the treatment of carotid-cavernous fistula.