Cellular localization of the full-length isoform of the type 2 corticotropin releasing factor receptor in the postnatal mouse cerebellar cortex

Corticotropin releasing factor (CRF) and its cognate receptors, defined as Type 1 and Type 2 have been localized within the cerebellum. The Type 2 CRF receptor (CRF-R2) is known to have both a full length (CRF-R2alpha) and a truncated (CRF-R2alpha-tr) isoform. A recent study documented CRF-R2alpha primarily in Bergann glia and astrocytes, as well as in populations of Purkinje cells in the adult cerebellum. The goal of the present study is to determine if CRF-R2alpha is present in the postnatal cerebellum, and if so to describe its cellular distribution. RT-PCR data showed that CRF-R2alpha is expressed in the mouse cerebellum from birth through postnatal day 21. Between birth and P14, CRF-R2alpha-immunoreactivity was localized within the somata of Purkinje cells, and migrating GABAergic interneurons. GFAP-immunoreactive astrocytes, including Bergmann glia, also expressed CRF-R2alpha-immunoreactivity from P3-P14. There is a change, however, in CRF-R2alpha immunolabeling within neurons as the cerebellum matures. Compared to its expression in the adult cerebellum, Purkinje cells, and GABAergic interneurons showed more extensive CRF-R2alpha immunolabeling during early postnatal development. We postulate that CRF-R2alpha could be involved in developmental events related to the survival and differentiation of Purkinje cells and GABAergic neurons, whereas in the adult, this isoform of the CRF receptor family is likely involved in modulating Bergmann glia that have been shown to play a role in regulating the synaptic environment around Purkinje neurons.     

Peri-stent reference segment plaque burden is associated with disease progression in saphenous vein grafts (a serial intravascular ultrasound assessment)

We are aware of no studies of peri-stent disease progression or luminal compromise in saphenous vein graft (SVG) lesions. We used serial intravascular ultrasound (IVUS) to assess disease progression in peri-stent saphenous vein bypass graft reference segments. We studied 37 peri-stent SVG reference segments in 21 patients; 16 were proximal and 21 were distal to the stent. The same anatomic image slice was analyzed after the intervention and at follow-up; this site was 3.68 +/- 2.22 mm from the stent edge. Graft age was 10.1 +/- 5.4 years, and mean follow-up duration was 13 months (range 3 to 61). Overall, change in SVG area, change in lumen area, and change in plaque burden correlated with postintervention plaque burden (r = 0.448, p = 0.005; r = -0.584, p <0.001; and r = 0.507, p = 0.001, respectively). For the proximal edge, change in lumen area correlated with change in plaque area (r = -0.951, p <0.001), but not with change in SVG area (r = -0.337, p = 0.201). For the distal edge, change in lumen area correlated more strongly with change in plaque area (r = -0.982, p <0.001) than with change in SVG area (r = -0.624, p = 0.003). When peri-stent reference segments were divided into 2 groups according to postintervention plaque burden (>50% [n = 20] vs <50% [n = 17]), there was a greater decrease in lumen area (-1.12 +/- 0.81 vs -0.33 +/- 0.26 mm(2), p <0.001) and greater increases in SVG area (0.26 +/- 0.29 vs 0.09 +/- 0.09 mm(2), p = 0.027), plaque area (1.37 +/- 0.96 vs 0.42 +/- 0.30 mm(2), p <0.001), and plaque burden (8.2 +/- 5.6% vs. 2.8 +/- 1.6%, p <0.001) in segments with a plaque burden >50%. In conclusion, peri-stent reference segment SVG disease progression and lumen loss were more significant in segments with a greater postintervention plaque burden after implantation of a bare metal stent or drug-eluting stent.     

Two for one: salvage of bilateral lower extremities with a single free flap

It is thought that free muscle flaps may remain dependent on their original pedicle for more than 1-year postoperation, particularly in the lower extremity of patients with peripheral vascular disease. We present the first case report of bilateral lower extremity salvage with a single rectus abdominis myocutaneous free flap by transecting the main pedicle. The pedicle of the free flap, going to the contralateral extremity, was safely divided at 6-weeks postoperation. A tourniquet was used to compress the pedicle at the division point to assess viability of the flap distal to the point of occlusion prior to transection of the flap.     

Anterior and middle cranial fossa skull base reconstruction using microvascular free tissue techniques: surgical complications and functional outcomes

Surgical ablation for oncologic disease requiring skull base resection can result in both facial disfigurement and a complex wound defect with exposed orbital content, oral cavity, bone, and dural lining. Inadequate reconstruction can result in brain abscesses, meningitis, osteomyelitis, visual disturbances, speech impairment, and altered oral intake. This study assesses the functional outcomes of patients who undergo anterior and middle cranial fossa skull base reconstruction using microsurgical free tissue transfer techniques. Using a prospectively maintained database, a 10-year, single institution retrospective chart review was performed on patients who had surgery for anterior and middle cranial base tumor resections. The type of resection, reconstruction method, complication rate, and functional outcomes were reviewed. From 1992 to 2003, 70 patients (49 men, 21 women) with a mean age of 54 (age 6-78) underwent anterior and middle cranial skull base tumor resection and reconstruction. The patients were divided into the following groups: maxillectomy with orbital content preservation (n = 21), orbitomaxillectomy with palatal preservation (n = 26), and orbitomaxillectomy with palatal resection (n = 23). The average length of hospital stay was 12.6 days. The vertical rectus abdominis myocutaneous flap was used in the majority of cases to correct midface defects. Two flaps required emergent re-exploration; however, there were no flap failures. Early and late postoperative complications were investigated. Cerebrospinal fluid was observed infrequently (7%) and did not require additional surgical intervention. Intracranial abscesses were encountered rarely (1.4%). Patients who had maxillectomy with orbital preservation and reconstruction had minor ophthalmologic eyelid changes that occurred frequently. Patients who required palatal reconstruction had a normal or intelligible speech (93%) and unrestricted or soft diet (88%). Using a multidisciplinary surgical team approach, there is an increasing role for reconstruction of complex oncologic midface resection defects using microvascular surgical techniques. Early/late complications and functional problems after anterior cranial base resections are uncommon when free tissue transfer is used concomitantly.     

Inhibition of dendritic cell differentiation and accumulation of myeloid-derived suppressor cells in cancer is regulated by S100A9 protein

Accumulation of myeloid-derived suppressor cells (MDSCs) associated with inhibition of dendritic cell (DC) differentiation is one of the major immunological abnormalities in cancer and leads to suppression of antitumor immune responses. The molecular mechanism of this phenomenon remains unclear. We report here that STAT3-inducible up-regulation of the myeloid-related protein S100A9 enhances MDSC production in cancer. Mice lacking this protein mounted potent antitumor immune responses and rejected implanted tumors. This effect was reversed by administration of wild-type MDSCs from tumor-bearing mice to S100A9-null mice. Overexpression of S100A9 in cultured embryonic stem cells or transgenic mice inhibited the differentiation of DCs and macrophages and induced accumulation of MDSCs. This study demonstrates that tumor-induced up-regulation of S100A9 protein is critically important for accumulation of MDSCs and reveals a novel molecular mechanism of immunological abnormalities in cancer.     

HLA–DR1001 presents “altered‐self” peptides derived from joint‐associated proteins by accepting citrulline in three of its binding pockets

Objective

HLA–DRB1*1001 (DR1001) is a shared epitope allele associated with rheumatoid arthritis (RA). The present study was undertaken to assess the capacity of DR1001 to accommodate citrulline in its binding pockets and to identify citrullinated T cell epitopes derived from joint‐associated proteins.

Methods

The binding of peptide derivatives containing citrulline, arginine, and other amino acid substitutions was measured. A prediction algorithm was developed to identify arginine‐containing sequences from joint‐associated proteins that preferentially bind to DR1001 upon citrullination. Unmodified and citrullinated versions of these sequences were synthesized and were utilized to stimulate CD4+ T cells from healthy subjects and RA patients. Responses were measured by class II major histocompatibility complex tetramer staining and confirmed by isolating CD4+ T cell clones.

Results

DR1001 accepted citrulline, but not arginine, in 3 of its anchoring pockets. The prediction algorithm identified sequences that preferentially bound to DR1001 with arginine replaced by citrulline. Three of these sequences elicited CD4+ T cell responses. T cell clones specific for these sequences proliferated only in response to citrullinated peptides.

Conclusion

Conversion of arginine to citrulline generates “altered‐self” peptides that can be bound and presented by DR1001. Responses to these peptides implicate the corresponding proteins (fibrinogen α, fibrinogen β, and cartilage intermediate‐layer protein) as relevant antigens. The finding of preferential responses to citrullinated sequences suggests that altered peptide binding affinity due to this posttranslational modification may be an important factor in the initiation or progression of RA. As such, measuring responsiveness to these peptides may be useful for immunologic monitoring.

     

Renal function after elective infrarenal aortic aneurysm repair in patients with pelvic kidneys

Pelvic kidneys complicate aortic reconstructions because of increased risk of renal ischemia. Strategies for protection include shunting, cooling, and reliance on collaterals. A review identified two congenital pelvic kidney (not solitary) and five transplanted kidney patients who underwent elective abdominal aortic aneurysm repair. For congenital pelvic kidneys, topical cooling was used in one patient while no preservation was performed for the other patient. Three transplanted kidney patients were shunted, and one had endovascular repair. Postoperative creatinine values were compared to preoperative values. The two congenital pelvic kidney patients had no significant elevation of creatinine postoperatively. The transplanted kidney patient who underwent endovascular repair had no increase in creatinine postoperatively. All transplanted kidney patients who had open repair had significant but transient increase in creatinine postoperatively. Three patients who were shunted intraoperatively had normalization of creatinine. The patient who had persistent elevation of creatinine at discharge was not shunted. Aortorenal shunting or endovascular repair in transplanted pelvic kidney patients maintains renal function. For patients with congenital pelvic kidneys and adequate collaterals, cooling and collateral perfusion is usually sufficient. Though experience is limited, endovascular repair is likely to be superior to open repair in minimizing renal ischemia.