Neuraminidase and SIGLEC15 modulate the host defense against pulmonary aspergillosis

Influenza-associated pulmonary aspergillosis (IAPA) has been reported increasingly since the advent of use of neuraminidase (NA) inhibitors following the 2009 influenza pandemic. We hypothesize that blocking host NA modulates the immune response against Aspergillus fumigatus. We demonstrate that NA influences the host response against A. fumigatus in vitro and that oseltamivir increases the susceptibility of mice to pulmonary aspergillosis. Oseltamivir impairs the mouse splenocyte and human peripheral blood mononuclear cell (PBMC) killing capacity of A. fumigatus, and adding NA restores this defect in PBMCs. Furthermore, the sialic acid-binding receptor SIGLEC15 is upregulated in PBMCs stimulated with A. fumigatus. Silencing of SIGLEC15 decrease PBMC killing of A. fumigatus. We provide evidence that host NA activity and sialic acid recognition are important for anti-Aspergillus defense. NA inhibitors might predispose individuals with severe influenza to invasive aspergillosis. These data shed light on the pathogenesis of invasive fungal infections and may identify potential therapeutic targets.

Triazole resistance surveillance in Aspergillus fumigatus

Triazole resistance is an increasing concern in the opportunistic mold Aspergillus fumigatus. Resistance can develop through exposure to azole compounds during azole therapy or in the environment. Resistance mutations are commonly found in the Cyp51A-gene, although other known and unknown resistance mechanisms may be present. Surveillance studies show triazole resistance in six continents, although the presence of resistance remains unknown in many countries. In most countries, resistance mutations associated with the environment dominate, but it remains unclear if these resistance traits predominately migrate or arise locally. Patients with triazole-resistant aspergillus disease may fail to antifungal therapy, but only a limited number of cohort studies have been performed that show conflicting results. Treatment failure might be due to diagnostic delay or due to the limited number of alternative treatment options. The ISHAM/ECMM Aspergillus Resistance Surveillance working group was set up to facilitate surveillance studies and stimulate international collaborations. Important aims are to determine the resistance epidemiology in countries where this information is currently lacking, to gain more insight in the clinical implications of triazole resistance through a registry and to unify nomenclature through consensus definitions.

Thyrotropin-induced hyperthyroidism: evidence for a common progenitor stem cell

A 36-year-old woman with hyperthyroidism, elevated blood thyroid-stimulating hormone (TSH) and alpha-subunit levels, amenorrhea, hyperprolactinemia and no evidence of acromegaly, was found to have a pituitary adenoma containing TSH, alpha-subunit and growth hormone by immunohistochemistry. Preoperative testing revealed elevated TSH and alpha-subunit with no response to thyrotropin-releasing hormone (TRH) but a normal response in prolactin to TRH. Culture of the pituitary cells showed release of TSH, alpha-subunit and prolactin. In vitro, TRH failed to cause TSH discharge; however, it increased prolactin concentrations in the culture medium. Triiodothyronine, added to the pituitary cell culture, resulted in no inhibition of TSH and prolactin discharge. By electron microscopy, the adenoma cells showed features of thyrotrophs. However, some adenoma cells contained fibrous bodies characteristic of some growth hormone cell tumors and acidophil stem cell adenomas, suggesting that the adenoma originated in a common progenitor cell.

Cervical distribution of iodine 131 following total thyroidectomy for thyroid cancer

The use of postoperative radioiodine thyroid scanning has questioned whether total thyroidectomy is surgically possible. Similar to earlier studies, we have found functioning iodine 131 (131I)-avid thyroid tissue in our patients following total thyroidectomy for thyroid cancer. Preoperative and postoperative thyroid scans were compared in 24 patients to study the cervical location of postthyroidectomy residual thyroid tissue. Thyroid scanning detected 44 distinct sites of uptake. Thirty-eight of these foci were located either at the extremes of the upper poles of the thyroid gland (24) or along the embryonic thyroid descent tract (14). We conclude that these foci of 131I uptake represent incomplete resection of normal thyroid tissue, and that surgical attention to these areas should result more frequently in extirpation of the entire thyroid gland.

Relative decreased splenic uptake of Tc-99m-sulfur colloid in patients with pancreatic carcinoma

Relative spleen/liver activity ratio was determined from posterior projection images using a photodensitometric method. Ratios from scans of 22 patients with proven pancreatic carcinoma (12 from rectilinear scans and 10 from scintillation camera images) were determined and compared to studies from patients documented as normal and to randomly selected liver/spleen imaging studies which had been previously interpreted as normal. The mean ratio from the pancreatic carcinoma group was significantly lower than the means of the respective normal groups (p[t] less than .0001 for rectilinear scans and p[t] less than .001 for scintigrams). There was no significant difference between the means of the proven normal and randomly selected normal groups or between the two pancreatic carcinoma groups. Splenic vascular alteration is discussed as a possible reason for decreased splenic distribution of Tc-99m-sulfur colloid in this patient group.

Glomerular filtration rate in children with advanced chronic renal failure: methods of determination and clinical applications

The rationale, significance and pitfalls of currently available methods for the determination of glomerular filtration rates in children with advanced chronic renal diseases are reviewed. Normal renal clearances in infants and children from birth to adulthood are presented. Methods of serial measurements of renal function, especially by the reciprocals of serum creatinine concentrations, are evaluated. They are applied clinically to monitor the effectiveness of conservative and new modalities of treatment, such as dietary supplementation with essential amino acids plus their keto analogues, and to determine that 1,25-dihydroxyvitamin-D3 treatment of renal osteodystrophy does not accelerate the deterioration of renal function in children with chronic renal insufficiency.