Familial idiopathic basal ganglia calcification with a heterozygous missense variant (c.902C>T/p.P307L) in SLC20A2 showing widespread cerebrovascular lesions.

We describe a postmortem case of familial idiopathic basal ganglia calcification (FIBGC) in a 72-year-old Japanese man. The patient showed progressive cognitive impairment with a seven-year clinical course and calcification of the basal ganglia, thalami, and cerebellar dentate nuclei. A novel heterozygous missense variant in SLC20A2 (c.920C>T/p.P307L), a type III sodium-dependent phosphate transporter (PiT-2), was subsequently identified, in addition to typical neuropathological findings of FIBGC, such as capillary calcification of the occipital gray matter, confluent calcification of the basal ganglia and cerebellar white matter, widespread occurrence of vasculopathic changes, cerebrovascular lesions, and vascular smooth muscle cell depletion. Immunohistochemistry for PiT-2 protein revealed no apparent staining in endothelial cells in the basal ganglia and insular cortex; however, the immunoreactivity in endothelial cells of the cerebellum was preserved. Moreover, Western blot analysis identified preserved PiT-2 immunoreactivity signals in the frontal cortex and cerebellum. The variant identified in the present patient could be associated with development of FIBGC and is known to be located at the large intracytoplasmic part of the PiT-2 protein, which has potential phosphorylation sites with importance in the regulation of inorganic phosphate transport activity. The present case is an important example to prove that FIGBC could stem from a missense variant in the large intracytoplasmic loop of the PiT-2 protein. Abnormal clearance of inorganic phosphate in the brain could be related to the development of vascular smooth muscle damage, the formation of cerebrovascular lesions, and subsequent brain calcification in patients with FIBGC with SLC20A2 variants.

Bananas decrease acetaminophen potency in in vitro assays.

Edible portions of bananas contain high levels of polyphenol oxidase, which catalyzes reactions in the melanin formation pathway. Tyrosine, a physiological substrate of polyphenol oxidase, has an analogous structure to acetaminophen. We investigated whether banana extract causes structural changes in acetaminophen and a decrease in its potency. Acetaminophen concentration in banana extract was measured under different conditions to characterize incompatibility. Reaction products in solution were identified using liquid chromatography/electrospray ionization/mass spectrometry (LC/ESI/MS). Acetaminophen potency decreased with time in the presence of banana extract. The reaction proceeded most efficiently in temperatures 30-37°C and neutral to weakly acidic conditions. Molecular ion peaks derived from the oxidized catechol moiety of acetaminophen were identified in LC/ESI/MS spectra. Our findings suggest that incorporation or simultaneous administration of acetaminophen medication and banana juice may result in decreased efficacy of the clinically important drug. This interaction is likely due to the oxidation of acetaminophen by polyphenol oxidase activity in banana pulp. Therefore, we investigated and characterized a novel interaction between bananas and acetaminophen. To establish a safe and effective antipyretic analgesic regimen using acetaminophen, future studies of this interaction are expected to be performed in humans.