Prospective, multicenter study of antimicrobial-coated, noncrosslinked, acellular porcine dermal matrix (XenMatrix™ AB Surgical Graft) for hernia repair in all centers for disease control and prevention wound classes: 24-month follow-up cohort.

Prospective, multicenter, single-arm study of antimicrobial-coated, noncrosslinked, acellular porcine dermal matrix (AC-PDM) in a cohort involving all centers for disease control and prevention wound classes in ventral/incisional midline hernia repair (VIHR). Materials and methods: Seventy-five patients (mean age 58.6±12.7 years; BMI 31.3±4.9 kg/m2) underwent ventral/incisional midline hernia repair with AC-PDM. Surgical site occurrence (SSO) was assessed in the first 45 days post-implantation. Length of stay, return to work, hernia recurrence, reoperation, quality of life, and SSO were assessed at 1, 3, 6, 12, 18, and 24 months. Results: 14.7% of patients experienced SSO requiring intervention within 45 days post-implantation, and 20.0% thereafter (>45 d post-implantation). Recurrence (5.8%), definitely device-related adverse events (4.0%), and reoperation (10.7%) were low at 24 months; all quality-of-life indicators were significantly improved compared to baseline. Conclusion: AC-PDM exhibited favourable results, including infrequent hernia recurrence and definitely device-related adverse events, with reoperation and SSO comparable to other studies, and significantly improved quality of life.

Dehydrated Human Amnion/Chorion Grafts May Accelerate the Healing of Ulcers on Free Flaps in Patients With Venous Insufficiency and/or Lymphedema.

OBJECTIVE: Ulceration of free flaps in patients with venous insufficiency and/or lymphedema is an uncommon but challenging problem. We hypothesized that dehydrated human amnion/chorion membrane (Epifix) grafts would accelerate healing of these challenging ulcers. METHODS: Retrospective analysis of prospectively acquired data identified 8 lower extremity free flaps with ulcerations in the context of venous insufficiency and/or lymphedema. The first 4 were flaps that had been treated with conservative wound care to healing. The second group was treated conservatively initially but then converted to treatment with dehydrated human amnion/chorion membrane grafts. The primary endpoint was time to healing. RESULTS: Comparison of Kaplan-Meier survival curves revealed a significant difference between the conservatively and dehydrated human amnion/chorion membrane-treated flap ulcers, favoring graft treatment (P = .0361). In those ulcers that healed, the average time to healing was 87 days for the conservative treatment group and 33 days for the dehydrated human amnion/chorion membrane treatment group (with an average of 1.7 grafts per ulcer). CONCLUSIONS: Dehydrated human amnion/chorion membrane may accelerate healing of ulcers on lower extremity free flaps in patient with lymphedema and/or venous disease in the treated leg.

Cranial and Cervical Muscular Weakness in Mitochondrial Myopathy Is Associated With Resolution of Migraine Headaches: Further Evidence That Muscular Compression of Cranial and Peripheral Nerves Is a Cause of Headache in a Subset of Patients With Migraine.

OBJECTIVE: A significant subset of patients with migraine headaches has pain relief after neuroplasty/muscular decompression of select cranial and cervical nerves. In the majority of cases, compression occurs secondary to compression of the nerves by adjacent muscles. Previous studies have shown that both surgical decompression and chemical denervation (eg, botulinum toxin) provide relief of migraine headaches; however, controversy remains. If some migraine headaches are caused by muscular compression, then paresis of the compressing muscles by underlying myopathic/metabolic disease should result in migraine relief in some patients. METHODS: We report a case of mitochondrial myopathy causing weakness primarily of the muscles of facial expression and the neck in the context of chronic migraine headaches (>20-year history). Muscle biopsy was obtained to confirm the myopathic diagnosis. RESULTS: There was complete resolution of the patient's migraine headaches that occurred simultaneously with the onset of symptomatic paresis of the muscles of facial expression and the neck. The relief has persisted for more than 10 months. Neurologic evaluation and muscle biopsy confirmed a diagnosis of mitochondrial myopathy. CONCLUSIONS: Pathologic paresis/paralysis of facial and/or cervical muscles can result in persistent resolution of migraine headache pain, giving further evidence to the concept that peripheral and/or cranial nerve compression causes migraine headache pain in a subset of patients with a diagnosis of migraine.

The ABC transporter, AbcB3, mediates cAMP export in D. discoideum development.

Extracellular cAMP functions as a primary ligand for cell surface cAMP receptors throughout Dictyostelium discoideum development, controlling chemotaxis and morphogenesis. The developmental consequences of cAMP signaling and the metabolism of cAMP have been studied in great detail, but it has been unclear how cells export cAMP across the plasma membrane. Here we show pharmacologically and genetically that ABC transporters mediate cAMP export. Using an evolutionary-developmental biology approach, we identified several candidate abc genes and characterized one of them, abcB3, in more detail. Genetic and biochemical evidence suggest that AbcB3 is a component of the cAMP export mechanism in D. discoideum development.

Reoperative selective sentinel lymphadenectomy combined with lymphoscintigraphy is technically feasible for cutaneous tumors of the upper extremity after radical dissection of regional lymph node basins for breast cancer.

OBJECTIVE: The rising incidence of melanoma and the high prevalence of breast cancer have generated a new scientific problem-how do the regional lymph node basins function after radical lymphadenectomy and are lymphatic drainage patterns altered after radical lymphadenectomy? Furthermore, after radical lymphadenectomy, selective sentinel lymphadenectomy is still a technically feasible and valid staging tool in the upper extremity? Thus, our study asks if selective sentinel lymph node dissection is technically feasible after radical lymph node dissection of the regional draining basin of the upper extremity (axilla). METHODS: Retrospective review of a prospectively maintained database of patients was reviewed to identify patients who had lymphoscintigraphy and sentinel lymph node biopsy of the upper extremity after a radical axillary node dissection procedure. Imaging and pathology results were analyzed. RESULTS: Seven patients fulfilling the inclusion criteria were identified. The patients all had either melanoma or invasive squamous cell carcinoma, and sentinel lymph nodes were identified in 6 out of 7 patients. One patient had metastases to 2 sentinel lymph nodes. Alternative drainage pathways were identified in 29% of patients, and 14% of patients had no identifiable drainage basin on lymphoscintigraphy. CONCLUSIONS: Sentinel lymph node dissection is technically feasible after previous axillary dissection. Lymphoscintigraphy is an important perioperative tool as lymphatic drainage may be altered or not observed as evidenced in 43% of the studied patients. However, when lymphatic drainage is detected by lymphoscintigraphy, pathologically significant sentinel lymph nodes are surgically identifiable.

ABC transporters in Dictyostelium discoideum development.

ATP-binding cassette (ABC) transporters can translocate a broad spectrum of molecules across the cell membrane including physiological cargo and toxins. ABC transporters are known for the role they play in resistance towards anticancer agents in chemotherapy of cancer patients. There are 68 ABC transporters annotated in the genome of the social amoeba Dictyostelium discoideum. We have characterized more than half of these ABC transporters through a systematic study of mutations in their genes. We have analyzed morphological and transcriptional phenotypes for these mutants during growth and development and found that most of the mutants exhibited rather subtle phenotypes. A few of the genes may share physiological functions, as reflected in their transcriptional phenotypes. Since most of the abc-transporter mutants showed subtle morphological phenotypes, we utilized these transcriptional phenotypes to identify genes that are important for development by looking for transcripts whose abundance was unperturbed in most of the mutants. We found a set of 668 genes that includes many validated D. discoideum developmental genes. We have also found that abcG6 and abcG18 may have potential roles in intercellular signaling during terminal differentiation of spores and stalks.

Bacterial discrimination by dictyostelid amoebae reveals the complexity of ancient interspecies interactions.

BACKGROUND: Amoebae and bacteria interact within predator-prey and host-pathogen relationships, but the general response of amoeba to bacteria is not well understood. The amoeba Dictyostelium discoideum feeds on, and is colonized by, diverse bacterial species, including Gram-positive [Gram(+)] and Gram-negative [Gram(-)] bacteria, two major groups of bacteria that differ in structure and macromolecular composition. RESULTS: Transcriptional profiling of D. discoideum revealed sets of genes whose expression is enriched in amoebae interacting with different species of bacteria, including sets that appear specific to amoebae interacting with Gram(+) or with Gram(-) bacteria. In a genetic screen utilizing the growth of mutant amoebae on a variety of bacteria as a phenotypic readout, we identified amoebal genes that are only required for growth on Gram(+) bacteria, including one that encodes the cell-surface protein gp130, as well as several genes that are only required for growth on Gram(-) bacteria, including one that encodes a putative lysozyme, AlyL. These genes are required for parts of the transcriptional response of wild-type amoebae, and this allowed their classification into potential response pathways. CONCLUSIONS: We have defined genes that are critical for amoebal survival during feeding on Gram(+), or Gram(-), bacteria that we propose form part of a regulatory network that allows D. discoideum to elicit specific cellular responses to different species of bacteria in order to optimize survival.

Transcriptional profiling of Dictyostelium with RNA sequencing.

Transcriptional profiling methods have been utilized in the analysis of various biological processes in Dictyostelium. Recent advances in high-throughput sequencing have increased the resolution and the dynamic range of transcriptional profiling. Here we describe the utility of RNA sequencing with the Illumina technology for production of transcriptional profiles. We also describe methods for data mapping and storage as well as common and specialized tools for data analysis, both online and offline.

Designed cyclic permutants of HIV-1 gp120: implications for envelope trimer structure and immunogen design.

Most HIV-1 broadly neutralizing antibodies are directed against the gp120 subunit of the env surface protein. Native env consists of a trimer of gp120-gp41 heterodimers, and in contrast to monomeric gp120, preferentially binds CD4 binding site (CD4bs)-directed neutralizing antibodies over non-neutralizing ones. Some cryo-electron tomography studies have suggested that the V1V2 loop regions of gp120 are located close to the trimer interface. We have therefore designed cyclically permuted variants of gp120 with and without the h-CMP and SUMO2a trimerization domains inserted into the V1V2 loop. h-CMP-V1cyc is one such variant in which residues 153 and 142 are the N- and C-terminal residues, respectively, of cyclically permuted gp120 and h-CMP is fused to the N-terminus. This molecule forms a trimer under native conditions and binds CD4 and the neutralizing CD4bs antibodies b12 with significantly higher affinity than wild-type gp120. It binds non-neutralizing CD4bs antibody F105 with lower affinity than gp120. A similar derivative, h-CMP-V1cyc1, bound the V1V2 loop-directed broadly neutralizing antibodies PG9 and PG16 with ∼20-fold higher affinity than wild-type JRCSF gp120. These cyclic permutants of gp120 are properly folded and are potential immunogens. The data also support env models in which the V1V2 loops are proximal to the trimer interface.

Conserved developmental transcriptomes in evolutionarily divergent species.

BACKGROUND: Evolutionarily divergent organisms often share developmental anatomies despite vast differences between their genome sequences. The social amoebae Dictyostelium discoideum and Dictyostelium purpureum have similar developmental morphologies although their genomes are as divergent as those of man and jawed fish. RESULTS: Here we show that the anatomical similarities are accompanied by extensive transcriptome conservation. Using RNA sequencing we compared the abundance and developmental regulation of all the transcripts in the two species. In both species, most genes are developmentally regulated and the greatest expression changes occur during the transition from unicellularity to multicellularity. The developmental regulation of transcription is highly conserved between orthologs in the two species. In addition to timing of expression, the level of mRNA production is also conserved between orthologs and is consistent with the intuitive notion that transcript abundance correlates with the amount of protein required. Furthermore, the conservation of transcriptomes extends to cell-type specific expression. CONCLUSIONS: These findings suggest that developmental programs are remarkably conserved at the transcriptome level, considering the great evolutionary distance between the genomes. Moreover, this transcriptional conservation may be responsible for the similar developmental anatomies of Dictyostelium discoideum and Dictyostelium purpureum.

Dermabrasion for rhytids in the lateral canthal region.

Dermabrasion of the periorbital region has been traditionally contraindicated due to the fear of complications. A method for safe dermabrasion of the lateral canthal region is described. Lateral canthal dermabrasion has the demonstrated advantages of being economical and relatively free of pigmentary problems. The results for 25 consecutive cases with a follow-up period of 12 to 16 months have shown good to excellent results in the majority of cases, with 4 cases requiring further revision. The technique is not intended to replace the gold standard, laserbrasion of the periocular region, and is not demonstrated to be safe for resurfacing of the lower lid region. However, the technique, rapid and easy once the learning curve is completed, was not associated with significant complications in the current series of patients.

Design of immunogens that present the crown of the HIV-1 V3 loop in a conformation competent to generate 447-52D-like antibodies.

gp120 is a subunit of the envelope glycoprotein of HIV-1. The third variable loop region of gp120 (V3 loop) contains multiple immunodominant epitopes and is also functionally important for deciding cell-tropism of the virus. 447-52D is a monoclonal antibody that recognizes the conserved tip of the V3 loop in a beta-turn conformation. This antibody has previously been shown to neutralize diverse strains of the virus. In an attempt to generate an immunogen competent to generate 447-52D-like antibodies, the known epitope of 447-52D was inserted at three different surface loop locations in the small, stable protein Escherichia coli Trx (thioredoxin). At one of the three locations (between residues 74 and 75), the insertion was tolerated, the resulting protein was stable and soluble, and bound 447-52D with an affinity similar to that of intact gp120. Upon immunization, the V3 peptide-inserted Trx scaffold was able to generate anti-V3 antibodies that could compete out 447-52D binding to gp120. Epitope mapping studies demonstrated that these anti-V3 antibodies recognized the same epitope as 447-52D. Although the 447-52D-type antibodies were estimated to be present at concentrations of 50-400 microg/ml of serum, these were not able to effect neutralization of strains like JRFL and BAL but could neutralize the sensitive MN strain. The data suggest that because of the low accessibility of the V3 loop on primary isolates such as JRFL, it will be difficult to elicit a V3-specific, 447-52D-like antibody response to effectively neutralize such isolates.

Crystal structures of the Tie2 receptor ectodomain and the angiopoietin-2-Tie2 complex.

The Tie receptor tyrosine kinases and their angiopoietin (Ang) ligands play central roles in developmental and tumor-induced angiogenesis. Here we present the crystal structures of the Tie2 ligand-binding region alone and in complex with Ang2. In contrast to prediction, Tie2 contains not two but three immunoglobulin (Ig) domains, which fold together with the three epidermal growth factor domains into a compact, arrowhead-shaped structure. Ang2 binds at the tip of the arrowhead utilizing a lock-and-key mode of ligand recognition-unique for a receptor kinase-where two complementary surfaces interact with each other with no domain rearrangements and little conformational change in either molecule. Ang2-Tie2 recognition is similar to antibody-protein antigen recognition, including the location of the ligand-binding site within the Ig fold. Analysis of the structures and structure-based mutagenesis provide insight into the mechanism of receptor activation and support the hypothesis that all angiopoietins interact with Tie2 in a structurally similar manner.

Effect of chromium and zinc on insulin signaling in skeletal muscle cells.

Patients on total parenteral nutrition without Cr supplementation develop symptoms similar to those of diabetes. Zn has been implicated in diabetes because of its antioxidant properties and interaction with insulin. To study the effect of these metal ions on insulin signaling proteins, cultured mouse skeletal muscle cells was used as an in vitro model, as the tissue accounts for more than 80% of insulin-stimulated glucose disposal in the body. In the present study, it has been observed that both Cr and Zn, upon prolonged exposure, could stimulate tyrosine phosphorylation of insulin receptor (IR) even in the absence of insulin. Insulin-mediated IR tyrosine phosphorylation was enhanced by the treatment with both of the metal ions. Both Cr and Zn could phosphorylate insulin receptor substrate-1 (IRS-1). Phosphorylation of IRS-1 induced by metal ions was higher than that induced by insulin. Hence, both Cr and Zn were found to have insulin mimetic activity. Both of the metal ions were also found to potentiate insulin-mediated activation of IRS-1. The basal level of glucose uptake was also increased by prolonged treatment of the cells with the metal ions. The ions could also enhance the insulin-stimulated glucose uptake into the cells. Therefore, both Zn and Cr seem to have a positive effect on insulin signaling leading to glucose uptake.

Routine imaging of asymptomatic melanoma patients with metastasis to sentinel lymph nodes rarely identifies systemic disease.

HYPOTHESIS: The diagnostic yield of chest radiography; computed tomography (CT) of the chest, abdomen, and pelvis; and CT or magnetic resonance imaging of the brain in the initial evaluation of melanoma with metastasis to sentinel lymph nodes may not identify systemic disease. DESIGN: Retrospective analysis. SETTING: Tertiary care referral center. PATIENTS: Of 1183 patients identified from a database of individuals who underwent selective sentinel lymphadenectomy for primary melanoma (Breslow thickness, 0.2-30 mm), we studied 185 with at least 1 sentinel lymph node positive for metastatic melanoma (Breslow thickness, 0.8-14.5 mm). INTERVENTIONS: Chest radiography; CT of the chest, abdomen, and pelvis; and CT or magnetic resonance imaging of the brain after selective sentinel lymphadenectomy with positive sentinel lymph nodes. The medical records of the 185 patients were systematically reviewed by 4 physician reviewers, and data were extracted primarily from pathology and radiology reports. When medical records were unavailable, information was taken from formal clinic and inpatient progress notes. MAIN OUTCOME MEASURE: Diagnostic yield of imaging studies. RESULTS: The results of 0.5% of the imaging studies were positive for metastatic disease, 86% were negative, and 14% were indeterminate. Indeterminate results were confirmed to be negative by additional studies ranging from repeated imaging to invasive procedures, including thoracotomy and brain biopsy. The yields are as follows: chest radiography, 0%; chest CT, 0.7%; abdominal and pelvic CT, 0.7%; brain CT, 0%; and brain magnetic resonance imaging, 0%. Only 1 patient (0.5%) had detectable metastatic disease, and he had symptoms of systemic disease at the time of imaging. CONCLUSIONS: Computed tomography of the chest, abdomen and pelvis, and brain rarely reveals systemic metastasis at the time of selective sentinel lymphadenectomy. Routine imaging of asymptomatic patients at the time of selective sentinel lymphadenectomy is not indicated.