Rationale:Calcium-sensing receptor (CaSR) mutations can cause life-threatening neonatal severe hyperparathyroidism (NSHPT). The medical management of NSHPT is often challenging and complex. Here, we present a case of NSHPT caused by a novel homozygous CaSR mutation.Patient concerns:A Chinese female infant presented with poor feeding, constipation, severe hypotonia, and periodic bradycardia. Biochemistry tests revealed markedly elevated serum levels of Ca2+ and parathyroid hormone (PTH).Diagnoses:Genetic sequencing revealed a previously undescribed CaSR mutation in exon 3 (c.242T>A; p.I81K). A diagnosis of NSHPT secondary to homozygously inherited familial hypocalciuric hypercalcemia syndrome was established.Interventions:Cinacalcet was administered after the common treatments (low-calcium intake, hydration, and furosemide), calcitonin, and pamidronate therapy all failed.Outcomes:Serum Ca2+ decreased and stabilized with cinacalcet therapy. During a 10-month follow-up, total calcium was maintained within the high-normal range and PTH was normalized.Lessons:A trial of cinacalcet therapy might be undertaken in cases of NSHPT while definitive results of the genetic analysis are awaited.
Calcium regulation in the human heart is impaired during idiopathic dilated cardiomyopathy (IDC). Here, we analyze the structural basis for impairment in the regulatory mechanism. Regulation of contractility was monitored by MgATPase and Ca2+-binding assays as a function of calcium. Myofibrillar proteolysis and expression of troponin T isoforms were established by gel electrophoresis and by Western blots. Myofibrillar ATPase assays in low salt however, revealed a drastic lowering of calcium sensitivity in IDC myofibrils as indicated by reductions in both activation by high calcium and in EGTA-mediated inhibition of MgATPase. Structural changes in myofilament proteins were found in most IDC hearts, specifically proteolysis of myosin light chain 2 (LC2), troponin T and I (TnT and TnI), and sometimes a large isoform shift in TnT. IDC did not induce mutations in LC2 and troponin C (TnC), as established by cDNA sequence data from IDC cases, thus, calcium binding to IDC myofibrils was unaffected. Reassociation of IDC myofibrils with native LC2 raised MgATPase activation at high Ca2+ to control levels, while repletion with intact, canine TnI/TnT restored inhibition at low Ca2+. A model, identifying possible steps in the steric blocking mechanism of regulation, is proposed to explain IDC-induced changes in Ca2+-regulation. Moreover, shifts in TnT isoforms may imply either a genetic or a compensatory factor in the development and pathogenesis of some forms of IDC.
It is estimated that 20 million people in the United States have gallbladder disease. Of the patients who present to the Emergency Department (ED) with abdominal pain, 3-10% have acute cholecystitis [1]. Point-of-care ultrasound (POCUS) evaluation of the biliary system is a valuable tool to diagnose gallbladder disease and can greatly expedite the diagnostic evaluation of patients. One source of error in POCUS of the gallbladder is imaging nearby structures that can mimic the gallbladder, such as the duodenum.
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