CD44 is a phagocytic receptor

CD44, a transmembrane adhesion molecule involved in binding and metabolism of hyaluronan, has additional functions in inflammatory and immune responses, contributing to the ingestion and clearance of particles and apoptotic cells. Our goal was to determine the specific role of CD44 in phagocytosis and whether it functions as a primary or accessory phagocytic receptor. Using hyaluronan-coated beads and erythrocytes coated with antiCD44 antibodies as the phagocytic prey, we determined that CD44 mediates efficient phagocytosis in primary murine peritoneal macrophages and in the murine macrophage cell line RAW 264.7. In RAW cells, the phagocytic index for anti-CD44-coated erythrocytes was 25 +/- 3 (mean +/- SEM) compared with less than 1 for erythrocytes coated with isotype-matched control antibodies. Uptake of anti-CD44-coated erythrocytes was abrogated by pretreatment with a blocking antibody to CD44 and was absent in primary cultures of CD44-deficient murine macrophages. Down-regulation of Fc receptors by aggregated IgG-induced internalization, which blocks uptake of IgG-coated particles, had no effect on CD44-mediated particle engulfment. Using a combination of immunoprecipitation, pharmacologic inhibition, and genetic deletion, we determined that CD44-mediated phagocytosis involves Syk, Rac1, and phosphatidylinositol 3-kinase and induced activation of the phagocyte oxidase. We conclude that CD44 is a competent phagocytic receptor that efficiently mediates internalization of large particles.     

The Lanz® endotracheal tube decreases tracheal injury in dogs

PURPOSE: To determine, in dogs anesthetized with nitrous oxide (N2O), (whether the endotracheal tube (ETT) cuffed with a Lanz pressure regulating valve decreases the tracheal consequences of tracheal intubation. METHODS: Sixteen mixed-breed dogs were allocated to two groups according to the ETT used: Control group (n = 8) - Rüsch ETT, and Lanz group (n = 8) - ETT with Lanz pressure regulating valve. The ETT cuffs in both groups were inflated with air to an intracuff pressure of 30 cm H2O. Anesthesia was induced and maintained with pentobarbitone and N2O (1.5 L x min(-1)) and O2 (1 L x min(-1)). ETT cuff pressures were measured before (control) and 60, 120, and 180 min during N2O administration. The dogs were sacrificed, and biopsy specimens from four predetermined areas of the tracheal mucosa in contact with the ETT were collected for light and scanning electron microscopy (SM) examination. RESULTS: Cuff pressures in the Control group were higher than in the Lanz group at all time points studied (P < 0.001), with an increase over time only in the Control group (P < 0.001). Median neutrophilic inflammatory infiltration values of the epithelial surface, and in the subepithelial layer in contact with the cuff, were higher in the Control group as compared to the Lanz group (3.0 vs 1.0 and 3.0 vs 1.5 respectively) (P < 0.05). On SM examination, median histological grades were higher in the Control group compared to Lanz group (2.9 vs 1.9 respectively), (P < 0.05). CONCLUSIONS: The Lanz ETT decreases tracheal mucosal injury in dogs.     

A Study of Pipeline Drugs in Neuroendocrine Tumors

Purpose

Inhibition of neovessel development can stabilize tumor growth. A rapid in vitro method that can evaluate the effectiveness of anti-angiogenic drugs would aid in drug development. We tested a series of investigational agents to determine their ability to inhibit angiogenesis in our in vitro human angiogenesis model.

Methods

A total of 74 neuroendocrine tumors were tested with five therapeutic agents for anti-angiogenic activity. Angiogenic responses were assessed visually and the percent of tumor explants that developed an angiogenic response was determined. The extent of neovessel growth was rated using a validated semi-quantitative visual scale. Analysis of variance was used to compare treatment outcome results to control values for these angiogenic parameters.

Results

Vatalanib (2?×?10^?5?M) and patupilone (1?×?10^?8?M) were highly effective inhibitors of human tumor angiogenesis (mean overall angiogenic response for drug versus control 1.3 vs. 5.9 and 0.2 vs. 5.2, respectively) and were statistically significant at p <0.0001. Imatinib (2.5?×?10^?6?M) and everolimus (1?×?10^?8?M) were also effective (mean overall angiogenic response for drug versus control 2.2 vs. 5.9 and 4.5 vs. 5.9, respectively), and these were also statistically significant at p <0.0001. Pasireotide (1?×?10^?8?M) had no effect on angiogenesis (mean overall angiogenic response for drug vs. control 5.5 vs. 5.2).

Conclusions

Significant differences in angiogenic response to test drugs were noted in this neuroendocrine patient population. In vitro screening of a large series of fresh human tumors may be a cost-effective way to select drugs for continued clinical development.     

Temporal superficial arteritis as differential diagnosis in patients with atherosclerotic changes due to advanced chronic renal disease: case report and review of the literature

Giant cell arteritis is an autoimmune disease that affects medium and large caliber vessels, creating deposits of inflammatory clusters on the arterial wall. It is the most common form of large vessel vasculitis, but given the variability of biopsy efficiency and of other diagnostic strategies employed, the diagnosis of this disease is challenging. We report the case of a 69-year-old female patient who presented with neurological deficit and increased bilateral sensation in the temporal region associated with excruciating headache. Workup revealed calcification of the superficial temporal, vertebral and ophthalmic arteries, as well as suggestive findings on Doppler ultrasound such as the halo sign, pointing to superficial temporal arteritis though not excluding the possibility of those calcifications being consistent with atherosclerosis in a patient with advanced chronic renal disease, which has been reported as giving rise to false-positive results. Knowledge of the main differences between the 2 diagnoses is important, given the wide range of diagnostic imaging possibilities which can avoid the need for biopsy.     

Mucopolysaccharidosis type IV: report of 5 cases of Morquio Syndrome

Mucopolysaccharidosis type IV or Morquio Syndrome, is a lysosomal deposit disease, of autosomal recessive inheritance with a similar incidence in men and women. The clinical picture is of variable expressiveness, its phenotype is characterized by skeletal dysplasia that includes neck and short trunk, short stature, keel thorax, kyphosis, scoliosis, genus valgus, flat foot, coxa valga, gait disorders, instability of the cervical spine and wedge or ovoid vertebrae. The treatment is symptomatic, with enzyme replacement. We present a series of 5 cases, the product of 2 couples, with a confirmed diagnosis of Mucopolysaccharidosis type IV, and different clinical presentation.