Determinants of COVID-19 severity in Ethiopia: a multicentre case-control study.

Objective: It was necessary to understand the determinants of severe COVID-19 in order to deliver targeted healthcare services to prevent further complications and mortality. Identifying the factors associated with severe COVID-19 in Addis Ababa, Ethiopia, is the aim of this study.

Design: A case-control study was conducted from October 2021 to March 2022.

An underexploited invisible gold resource in the Archean sulphides of the Witwatersrand tailings dumps.

The tailings dumps originating from gold mining in South Africa's Witwatersrand still contain notable gold endowments. Most tailings reprocessing operations target a native gold fraction using re-milling and carbon-in-leach extraction; however, up to 50-70% of the remaining gold is still not recoverable and instead discarded to the re-dump stream along with abundant sulphides. The mineralogical deportment of this unrecoverable gold underwent a detailed investigation.

Paraganglioma of the sacral spinal canal.

Paragangliomas are tumors arising in the paraganglia. Involvement of the spine is less common, and usually takes the form of intradural compression of the cauda equina. We report here a case of a 60-year-old man with recurrent and progressive pain of his sacral and perineal area, accompanied by occasional rod and perineal hypoesthesia on admission.

Natural history of supratentorial hemangioblastomas in von Hippel-Lindau disease.

Background: Supratentorial hemangioblastomas are rare lesions, occurring either sporadically or in von Hippel-Lindau disease.

Objective: Following recent advances in our understanding of the natural history of von Hippel-Lindau-associated cerebellar and spinal hemangioblastomas, we conducted a study of the natural history of supratentorial hemangioblastomas in von Hippel-Lindau disease.

Methods: We reviewed a series of 18 supratentorial hemangioblastomas in 13 patients with von Hippel-Lindau disease.

Surgical treatment of posttraumatic syringomyelia.

Objective: The present study evaluates the effectiveness of 2 surgical procedures, shunting and untethering, for posttraumatic syringomyelia.

Methods: We retrospectively reviewed the medical charts of all surgical patients with posttraumatic syringomyelia in our department. Shunting was performed before 1997; after 1997, we used arachnoidolysis and untethering.