DNA Conformation Induces Adaptable Binding by Tandem Zinc Finger Proteins.

Tandem zinc finger (ZF) proteins are the largest and most rapidly diverging family of DNA-binding transcription regulators in mammals. ZFP568 represses a transcript of placental-specific insulin like growth factor 2 (Igf2-P0) in mice. ZFP568 binds a 24-base pair sequence-specific element upstream of Igf2-P0 via the eleven-ZF array. Both DNA and protein conformations deviate from the conventional one finger-three bases recognition, with individual ZFs contacting 2, 3, or 4 bases and recognizing thymine on the opposite strand. These interactions arise from a shortened minor groove caused by an AT-rich stretch, suggesting adaptability of ZF arrays to sequence variations. Despite conservation in mammals, mutations at Igf2 and ZFP568 reduce their binding affinity in chimpanzee and humans. Our studies provide important insights into the evolutionary and structural dynamics of ZF-DNA interactions that play a key role in mammalian development and evolution.

Burkholderia from Fungus Gardens of Fungus-Growing Ants Produces Antifungals That Inhibit the Specialized Parasite Escovopsis.

Within animal-associated microbiomes, the functional roles of specific microbial taxa are often uncharacterized. Here, we use the fungus-growing ant system, a model for microbial symbiosis, to determine the potential defensive roles of key bacterial taxa present in the ants' fungus gardens. Fungus gardens serve as an external digestive system for the ants, with mutualistic fungi in the genus Leucoagaricus converting the plant substrate into energy for the ants. The fungus garden is host to specialized parasitic fungi in the genus Escovopsis. Here, we examine the potential role of Burkholderia spp. that occur within ant fungus gardens in inhibiting Escovopsis. We isolated members of the bacterial genera Burkholderia and Paraburkholderia from 50% of the 52 colonies sampled, indicating that members of the family Burkholderiaceae are common inhabitants in the fungus gardens of a diverse range of fungus-growing ant genera. Using antimicrobial inhibition bioassays, we found that 28 out of 32 isolates inhibited at least one Escovopsis strain with a zone of inhibition greater than 1 cm. Genomic assessment of fungus garden-associated Burkholderiaceae indicated that isolates with strong inhibition all belonged to the genus Burkholderia and contained biosynthetic gene clusters that encoded the production of two antifungals: burkholdine1213 and pyrrolnitrin. Organic extracts of cultured isolates confirmed that these compounds are responsible for antifungal activities that inhibit Escovopsis but, at equivalent concentrations, not Leucoagaricus spp. Overall, these new findings, combined with previous evidence, suggest that members of the fungus garden microbiome play an important role in maintaining the health and function of fungus-growing ant colonies. IMPORTANCE Many organisms partner with microbes to defend themselves against parasites and pathogens. Fungus-growing ants must protect Leucoagaricus spp., the fungal mutualist that provides sustenance for the ants, from a specialized fungal parasite, Escovopsis. The ants take multiple approaches, including weeding their fungus gardens to remove Escovopsis spores, as well as harboring Pseudonocardia spp., bacteria that produce antifungals that inhibit Escovopsis. In addition, a genus of bacteria commonly found in fungus gardens, Burkholderia, is known to produce secondary metabolites that inhibit Escovopsis spp. In this study, we isolated Burkholderia spp. from fungus-growing ants, assessed the isolates' ability to inhibit Escovopsis spp., and identified two compounds responsible for inhibition. Our findings suggest that Burkholderia spp. are often found in fungus gardens, adding another possible mechanism within the fungus-growing ant system to suppress the growth of the specialized parasite Escovopsis.

Evaluation of Antegrade Intramedullary Compression Screw Fixation of Metacarpal Shaft Fractures in a Cadaver Model.

PURPOSE: Surgical options for displaced metacarpal shaft fractures include the use of Kirschner wires, plates and screws, and most recently, intramedullary headless compression screws (IMHCS), which have been reported using only retrograde insertion through the metacarpal head. We evaluated IMHCS fixation of metacarpal shaft fractures through an antegrade approach in a cadaver model. METHODS: We performed antegrade placement of IMHCS in 10 cadaver hands including all 5 digits (total of 50). Displaced transverse proximal metacarpal shaft fractures were created and reduced with a retrograde guidewire from the metacarpal head across the shaft fracture and exiting the metacarpal base. This was retrieved through a 6-mm dorsal wrist incision and overdrilled before the placement of a 4.1-mm-diameter IMHCS in the ring finger and a 4.7-mm screw in all other metacarpals. After IMHCS placement, carpometacarpal (CMC) joint violation was measured along with the optimal starting point for the guidewire on the metacarpal head relative to the dorsal cortex. RESULTS: In all 50 metacarpals, we achieved successful fracture reduction and fixation without violating the extensor mechanism at the wrist. Our retrograde guidewire entry point through the metacarpal head ranged from 4.2 to 4.7 mm volar to the dorsal cortex. The actual area of CMC joint violated by IMHCS placement was largest in the index CMC joint (4.9%), followed by the middle (3.7%), little (2.9%), ring (0.5%), and thumb joints (0.2%). CONCLUSIONS: Placement of IMHCS through an antegrade approach from the CMC joint can be performed effectively for all transverse metacarpal fractures, including the thumb, using a limited incision. There is minimal violation of the articular surfaces of the trapezium, capitate, and hamate for the thumb, middle, ring, and little metacarpals. CLINICAL RELEVANCE: Antegrade IMHCS fixation successfully avoids the potential morbidity of creating a metacarpal head articular surface or extensor mechanism defect at the metacarpophalangeal joint seen with the retrograde approaches.

An Anatomical Study of Metacarpal Morphology Utilizing CT Scans: Evaluating Parameters for Antegrade Intramedullary Compression Screw Fixation of Metacarpal Fractures.

PURPOSE: This study evaluated metacarpal morphology for antegrade placement of intramedullary headless compression screws (IMHCS) for metacarpal fracture fixation. METHODS: We analyzed 100 hand computed tomography scans to quantify cortical thickness, intramedullary diameter, and metacarpal lengths. In addition, dorsal or ulnar overhang of the metacarpals over their respective carpal bones was measured. We also predicted optimal entry points for guidewire placement at the metacarpal head. RESULTS: The ring finger metacarpal had the narrowest medullary canal width (coronal, 2.8 mm; sagittal, 3.5 mm). Not counting the thumb, the little finger metacarpal had the widest midshaft medullary width of 4.1 mm in the coronal plane and the middle metacarpal was widest in the sagittal plane with canal width of 3.9 mm. On average, there was maximal dorsal overhang at the base of the middle metacarpal (4.2 mm) and maximal ulnar overhang at the base of the small metacarpal (3.9 mm). The optimal entry point for guidewire placement over each metacarpal head was approximately 3.5 to 3.8 mm volar to the dorsal cortex. CONCLUSIONS: Minimum IMHCS diameters of 3.5 mm for the ring and 4.0 mm for the index, middle and little fingers are necessary to achieve interference fit within the medullary canal. Minimum screw lengths of 38 mm would be needed to ensure 6 mm fixation past the midshaft of the metacarpals. Antegrade IMHCS for fixation of proximal metacarpal fractures may be most feasible with thumb, middle, and little finger metacarpals because there was larger dorsal or ulnar overhang to allow screw placement without violating the carpometacarpal joints. CLINICAL RELEVANCE: Our analysis provides a reference guide for intramedullary screw sizes for each metacarpal of the hand to achieve interference fit with fracture fixation. Furthermore, the dorsal and ulnar overhangs of the metacarpal bases suggest the practicality of antegrade IMHCS fixation.

Breast Implant-Associated Bilateral B-Cell Lymphoma.

Lymphomas associated with implants are predominantly of T-cell type-with anaplastic large cell lymphoma (ALCL) being most reported. That said, to date, 6 cases of B-cell lymphoma associated with breast implants have been reported. All cases exhibited unilateral breast involvement. Here, the authors report a case of low-grade B-cell lymphoma occurring bilaterally in a 34-year-old woman with a history of Poly Implant Prosthese silicone implants at age 20, T-cell angioimmunoblastic lymphoma, and subsequent myeloablative double cord blood transplantation. Lymphoma cells were positive for CD20, CD5, BCL-2, CD21, CD23, IgD, IgM, with very low Ki-67 of 1%. Nevertheless, cases of ALCL associated with breast implants are rare but much more documented in the literature than B-cell lymphomas associated with breast implants, as in this patient. Identification of a relationship between breast cancer and silicone is still ongoing in the literature, with long-term clinical follow up required. More research will be necessary to fully characterize the occurrence, course, and association of this disease with breast implants in order to properly guide diagnosis and management.

Leptin Is Produced by Parathyroid Glands and Stimulates Parathyroid Hormone Secretion.

OBJECTIVE: We asked if leptin and its cognate receptor were present in normal and diseased parathyroid glands, and if so, whether they had any functional effects on parathyroid hormone (PTH) secretion in parathyroid neoplasms. BACKGROUND: The parathyroid glands acting through PTH play a critical role in the regulation of serum calcium. Based on leptin's recently discovered role in bone metabolism, we hypothesized these glands were the sites of a functional interaction between these 2 hormones. METHODS: From July 2010 to July 2011, 96 patients were enrolled in a prospective study of leptin and hyperparathyroidism, all of whom were enrolled based on their diagnosis of hyperparathyroidism, and their candidacy for surgical intervention provided informed consent. Immediately after parathyroidectomy, 100 to 300 mg of adenomatous or hyperplastic diseased parathyroid tissue was prepared and processed according to requirements of the following: in situ hybridization, immunohistochemistry, immunofluorescence by conventional and spinning disc confocal microscopy, electron microscopy, parathyroid culture, whole organ explant, and animal model assays. RESULTS: Leptin, leptin receptor (long isoform), and PTH mRNA transcripts and protein were detected in an overlapping fashion in parathyroid chief cells in adenoma and hyperplastic glands, and also in normal parathyroid by in situ hybridization, qRT-PCR, and immunohistochemistry. Confocal microscopy confirmed active exogenous leptin uptake in cultured parathyroid cells. PTH secretion in explants increased in response to leptin and decreased with leptin receptor signaling inhibition by AG490, a JAK2/STAT3 inhibitor. Ob/ob mice injected with mouse leptin exhibited increased PTH levels from baseline. CONCLUSIONS: Taken together, these data suggest that leptin is a functionally active product of the parathyroid glands and stimulates PTH release.

Surgical Excision and Adjuvant Brachytherapy vs External Beam Radiation for the Effective Treatment of Keloids: 10-Year Institutional Retrospective Analysis.

BACKGROUND: Surgically excised keloids reportedly recur at a rate of >45%. Post-excision radiation (RT) has been delivered via external beam radiotherapy (EBRT) or interstitial high dose rate (HDR) brachytherapy. Despite historical data showing 10% to 20% keloid recurrences with post-excision RT, there is a paucity of high-quality evidence comparing keloid recurrences between the two RT modalities. OBJECTIVES: We performed the largest single-institution case-control retrospective study (2004-2014) of keloid recurrence rates and complications between post-excision EBRT and HDR brachytherapy. METHODS: One-hundred and twenty-eight patients, with 264 keloid lesions, were treated by excision alone (n = 28), post-excision EBRT (n = 197), or post-excision HDR brachytherapy (n = 39). Patient and keloid recurrence data were analyzed using mixed effect Cox regression modeling with a statistical threshold of P < .05. RESULTS: Fifty-four percent of keloids recurred after surgical excision alone (9-month median follow up); 19% of keloids recurred with post-excision EBRT (42-month median follow up); 23% of keloids recurred with post-excision brachytherapy (12-month median follow up). Adjuvant EBRT and brachytherapy each showed significant control of keloid recurrence compared to excision alone (P < .01). EBRT significantly delayed the time of keloid recurrence over brachytherapy by a mean difference of 2.5 years (P < .01). CONCLUSIONS: Post-excision RT shows significant reduction in keloid recurrence compared to excision alone. While the recurrence control rates are not statistically different between EBRT and brachytherapy, keloids treated with EBRT recurred significantly later than those treated by HDR brachytherapy by a mean of 2.5 years. Further workup with a randomized control study will help to refine optimal adjuvant RT treatment. LEVEL OF EVIDENCE 3.

Hand Rejuvenation: A Comprehensive Review of Fat Grafting.

Dermal atrophy, bulging reticular veins, and prominent bones and tendons are characteristic of the aging hand. Demand for cosmetic procedures to restore a youthful appearance to the dorsum of the hand has risen in recent years. A review of the literature reveals that of the many options for hand restoration, autologous fat grafting stands out as the most promising choice compared with many available alternative options such as microdermabrasion, peeling agents, and dermal fillers. This article details the surgical technique and relevant anatomy necessary for successful hand rejuvenation. Future advancements may rely on further study into adipose-derived stem cells.

Evaluation of Percutaneous First Annular Pulley Release: Efficacy and Complications in a Perfused Cadaveric Study.

PURPOSE: Trigger finger is the most common entrapment tendinopathy, with a lifetime risk of 2% to 3%. Open surgical release of the flexor tendon sheath is a commonly performed procedure associated with a high rate of success. Despite reported success rates of over 94%, percutaneous trigger finger release (PFTR) remains a controversial procedure because of the risk of iatrogenic digital neurovascular injury. This study aimed to evaluate the safety and efficacy of traditional percutaneous and ultrasound (US)-guided first annular (A1) pulley releases performed on a perfused cadaveric model. METHODS: First annular pulley releases were performed percutaneously using an 18-gauge needle in 155 digits (124 fingers and 31 thumbs) of un-embalmed cadavers with restored perfusion. A total of 45 digits were completed with US guidance and 110 digits were completed without it. Each digit was dissected and assessed regarding the amount of release as well as neurovascular, flexor tendon, and A2 pulley injury. RESULTS: Overall, 114 A1 pulleys were completely released (74%). There were 38 partial releases (24%) and 3 complete misses (2%). No significant flexor tendon injury was seen. Longitudinal scoring of the flexor tendon was found in 35 fingers (23%). There were no lacerations to digital nerves and one ulnar digital artery was partially lacerated (1%) in a middle finger with a partial flexion contracture that prevented appropriate hyperextension. The ultrasound-assisted and blind PTFR techniques had similar complete pulley release and injury rates. CONCLUSIONS: Both traditional and US-assisted percutaneous release of the A1 pulley can be performed for all fingers. Perfusion of cadaver digits enhances surgical simulation and evaluation of PTFR beyond those of previous cadaveric studies. The addition of vascular flow to the digits during percutaneous release allows for Doppler flow assessment of the neurovascular bundle and evaluation of vascular injury. CLINICAL RELEVANCE: Our cadaveric data align with those of published clinical investigations for percutaneous A1 pulley release.

Sex-specific repression of dachshund is required for Drosophila sex comb development.

The origin of new morphological structures requires the establishment of new genetic regulatory circuits to control their development, from initial specification to terminal differentiation. The upstream regulatory genes are usually the first to be identified, while the mechanisms that translate novel regulatory information into phenotypic diversity often remain obscure. In particular, elaborate sex-specific structures that have evolved in many animal lineages are inevitably controlled by sex-determining genes, but the genetic basis of sexually dimorphic cell differentiation is rarely understood. In this report, we examine the role of dachshund (dac), a gene with a deeply conserved function in sensory organ and appendage development, in the sex comb, a recently evolved male-specific structure found in some Drosophila species. We show that dac acts during metamorphosis to restrict sex comb development to the appropriate leg region. Localized repression of dac by the sex determination pathway is necessary for male-specific morphogenesis of sex comb bristles. This pupal function of dac is separate from its earlier role in leg patterning, and Dac at this stage is not dependent on the pupal expression of Distalless (Dll), the main regulator of dac during the larval period. Dll acts in the epithelial cells surrounding the sex comb during pupal development to promote sex comb rotation, a complex cellular process driven by coordinated cell rearrangement. Our results show that genes with well-conserved developmental functions can be re-used at later stages in development to regulate more recently evolved traits. This mode of gene co-option may be an important driver of evolutionary innovations.

A strategy for the successful management of dermatofibrosarcoma protuberans.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a rare, locally invasive soft tissue sarcoma with extensive subclinical involvement. The National Comprehensive Cancer Network guidelines recommend immediate reconstruction in most cases. Our study reviewed the methods of treatment of DFSP at our institution, examined the types of closure used after surgical excision, and analyzed the prevalence of positive margins on permanent pathology after immediate closure after conventional non-Mohs excision of DFSP. METHODS: The charts of 25 patients treated with surgical excision and 16 with Mohs surgery from 1990 to 2009 for lesions consistent with DFSP were reviewed for clinical variables including disease state, tumor site, closure type, permanent pathology margin status, disease recurrence/persistence, and excisional margin size. RESULTS: The trunk, followed by the head and neck, were the most common sites for DFSP. No patients had distant metastasis at diagnosis or experienced recurrence in either the surgical excision or the Mohs surgery group. Twelve (48%) patients were found to have positive margins after initial surgical resection. All lesions treated with Mohs surgery had clear histological margins at completion. Average margin size for surgical excision patients was 2.33 cm (range, 0.75-4.5 cm), and 1.36 cm (range, 0.74-2.55 cm) for Mohs excision. The average duration of follow-up was 107.9 months. CONCLUSIONS: The extent of DFSP is difficult to determine intraoperatively with traditional surgical excision, which leads to a higher rate of positive margins. Considering this difficulty and the complications of reconstruction with positive margins, we believe that reconstruction after tumor resection should be dependent on definitive pathologic clearance of the tumor.

Disturbance-diversity relationships of microbial communities change based on growth substrate.

Disturbance events can impact ecological community dynamics. Understanding how communities respond to disturbances and how those responses can vary is a challenge in microbial ecology. In this study, we grew a previously enriched specialized microbial community on either cellulose or glucose as a sole carbon source and subjected them to one of five different disturbance regimes of varying frequencies ranging from low to high. Using 16S rRNA gene amplicon sequencing, we show that the community structure is largely driven by substrate, but disturbance frequency affects community composition and successional dynamics. When grown on cellulose, bacteria in the genera Cellvibrio, Lacunisphaera, and Asticcacaulis are the most abundant microbes. However, Lacunisphaera is only abundant in the lower disturbance frequency treatments, while Asticcacaulis is more abundant in the highest disturbance frequency treatment. When grown on glucose, the most abundant microbes are two Pseudomonas sequence variants and a Cohnella sequence variant that is only abundant in the highest disturbance frequency treatment. Communities grown on cellulose exhibited a greater range of diversity (1.95-7.33 Hill 1 diversity) that peaks at the intermediate disturbance frequency treatment or one disturbance every 3 days. Communities grown on glucose, however, ranged from 1.63 to 5.19 Hill 1 diversity with peak diversity at the greatest disturbance frequency treatment. These results demonstrate that the dynamics of a microbial community can vary depending on substrate and the disturbance frequency and may potentially explain the variety of diversity-disturbance relationships observed in microbial systems.IMPORTANCEA generalizable diversity-disturbance relationship (DDR) of microbial communities remains a contentious topic. Various microbial systems have different DDRs. Rather than finding support or refuting specific DDRs, we investigated the underlying factors that lead to different DDRs. In this study, we measured a cellulose-enriched microbial community's response to a range of disturbance frequencies from high to low, across two different substrates: cellulose and glucose. We demonstrate that the community displays a unimodal DDR when grown on cellulose and a monotonically increasing DDR when grown on glucose. Our findings suggest that the same community can display different DDRs. These results suggest that the range of DDRs we observe across different microbial systems may be due to the nutritional resources microbial communities can access and the interactions between bacteria and their environment.

Deepithelialized flap closure: an adjunct to complex ventral hernia repairs.

Ventral hernias are a major surgical challenge with complications such as wound separations, infections, and recurrences contributing to patient morbidity. We describe a new adjunctive technique that may be helpful in repairing difficult ventral hernias: it involves using an appropriately chosen, redundant abdominal skin edge that is deepithelialized and used to reinforce the hernia repair. A series of 7 patients aged 23 to 84 years in whom the technique was used is presented. All patients had complete repair of their incisional ventral hernia defects without complications of infection, wound dehiscence, seroma formation, reoperation, or hernia recurrence. Furthermore, patients reported a subjective improvement in performing daily activities. Mean follow-up in this series was 19.2 months, with a range from 15.0 to 26.8 months. Advantages include the redistribution of mechanical tension, reinforcement of the midline site of greatest pressure, elimination of dead space, and staggering of suture lines to prevent direct external contamination of prosthetic material should wound dehiscence occur.

Looking Back to Move Forward: The Current State of Research on the Clinical Applications of Camphor- and Menthol-Containing Agents.

Topically applied compounds containing camphor and menthol have been used to alleviate pain, cold symptoms, and pruritus, historically predominantly in East Asia. Being not studied well, they are less recognized in Western medicine. Given the commonality of pain, pruritus, and cold symptoms in addition to the growing need for non-opioid treatment options, the authors investigated clinical applications of such compounds for their over-counter usage. The purpose was to analyze current clinical research and applications regarding the use of these topical agents. This study involved a bibliometric analysis of peer-reviewed articles, published in English and indexed in PubMed from 2010 to 2022, pertaining to camphor- and menthol-containing compounds. There were 103 results, of which 15 (14.6%) articles were related to the treatment of disorders related to health, such as upper respiratory infection, pain, and pruritus. Excluded were "non-research" articles (e.g., letters to the editor), articles that do not involve human subjects, reports of improper application or misuse (e.g., ingestion), and articles pertaining to intraoral, intranasal, and ophthalmic agents. Of these articles, the originating journals, respective journal impact factor scores, publication years, study designs, and study topics were identified. Underlying trends and themes regarding clinically relevant research on these compounds were subsequently discerned. Based on this analysis, topical agents containing camphor and menthol are potentially effective at treating pain, upper respiratory infection symptoms, and pruritus in addition to potentially functioning as an antimicrobial. However, with a limited number of studies addressing these compounds' uses in each application, no definitive recommendation can be made regarding their use. Given the promising results of earlier studies, the authors recommend that more primary research, particularly randomized, double-blind controlled studies, be done regarding clinical applications of these substances.

Ideal Length and Diameter for Intramedullary Screw Fixation of Metacarpal Fractures: A Biomechanical Study.

Purpose: This biomechanical study evaluated the effect of intramedullary screw diameter and length relative to 3-point bending force and torsional force when used to stabilize metacarpal shaft fractures. Methods: Transverse osteotomies were made in the proximal metacarpal shaft in 36 middle finger metacarpal fourth-generation composite Sawbones. To compare screw diameters, antegrade intramedullary screws of 30-mm length were placed in 6 metacarpals, which included 4.7-mm Acutrak 2, Standard Acutrak 2 (4.0 mm), and Mini-Acutrak 2 (3.5 mm) screws. To compare screw lengths, metacarpals were fixated with Standard Acutrak 2 screws of 26, 30, or 34 mm in length, with screw tips bypassing the osteotomy by 6, 10, or 14 mm, respectively. A 6 degrees of freedom robot was used for torsional and 3-point bending testing. Results: Increasing screw diameter demonstrated significant differences in both 3-point bending and torsional strengths. Maximum torsional loads were 69 Ncm (4.7-mm Acutrak 2), 45 Ncm (Standard Acutrak 2), and 27 Ncm (Mini-Acutrak 2) (P < .05). Loads to failure in the 3-point bending tests were 916 N (4.7-mm Acutrak 2), 713 N (Standard Acutrak 2), and 284 N (Mini-Acutrak 2) (P < .05). Differing screw lengths demonstrated significant differences with maximum torsional loads when comparing the 26-mm screws (22 Ncm) with 30- and 34-mm screws (45 and 55 Ncm, respectively) (P < .05). The 3-point dorsal bending strengths were significantly different between the 26-mm screws (320 N) and 30- and 34-mm screws (713 N and 702 N, respectively) (P < .05). Conclusions: The results demonstrated significantly higher torsional strength and resistance to 3-point bending with larger intramedullary screw diameters. Further, when selecting the intramedullary screw length, the screw tip should pass at least 10 mm beyond the fracture. Clinical Relevance: This study provided biomechanical evidence to guide surgeons in selecting intramedullary screw diameter and length for treating metacarpal fractures.

A new ferrocene derivative blocks KRAS localization and function by oxidative modification at His95.

Ras proteins are membrane-bound GTPases that regulate essential cellular processes at the plasma membrane (PM). Constitutively active mutations of K-Ras, one of the three Ras isoforms in mammalian cells, are frequently found in human cancers. Ferrocene derivatives, which elevate cellular reactive oxygen species (ROS), have shown to block the growth of non-small cell lung cancers (NSCLCs) harboring oncogenic mutant K-Ras. Here, we developed and tested a novel ferrocene derivative on the growth of human pancreatic ductal adenocarcinoma (PDAC) and NSCLC. Our compound inhibited the growth of K-Ras-dependent PDAC and NSCLC and abrogated the PM binding and signaling of K-Ras, but not other Ras isoforms. These effects were reversed upon antioxidant supplementation, suggesting a ROS-mediated mechanism. We further identified K-Ras His95 residue in the G-domain as being involved in the ferrocene-induced K-Ras PM dissociation via oxidative modification. Together, our studies demonstrate that the redox system directly regulates K-Ras PM binding and signaling via oxidative modification at the His95, and proposes a role of oncogenic mutant K-Ras in the recently described antioxidant-induced metastasis in K-Ras-driven lung cancers.

Disturbance-Diversity Relationships of Microbial Communities Change Based on Growth Substrate.

Disturbance events can impact ecological community dynamics. Understanding how communities respond to disturbances, and how those responses can vary, is a challenge in microbial ecology. In this study, we grew a previously enriched specialized microbial community on either cellulose or glucose as a sole carbon source, and subjected them to one of five different disturbance regimes of varying frequencies ranging from low to high. Using 16S rRNA gene amplicon sequencing, we show that community structure is largely driven by substrate, but disturbance frequency affects community composition and successional dynamics. When grown on cellulose, bacteria in the genera Cellvibrio, Lacunisphaera, and Asticaccacaulis are the most abundant microbes. However, Lacunisphaera is only abundant in the lower disturbance frequency treatments, while Asticaccaulis is more abundant in the highest disturbance frequency treatment. When grown on glucose, the most abundant microbes are two Pseudomonas sequence variants, and a Cohnella sequence variant that is only abundant in the highest disturbance frequency treatment. Communities grown on cellulose exhibited a greater range of diversity (0.67-1.99 Shannon diversity and 1.38-5.25 Inverse Simpson diversity) that peak at the intermediate disturbance frequency treatment, or 1 disturbance every 3 days. Communities grown on glucose, however, ranged from 0.49-1.43 Shannon diversity and 1.37- 3.52 Inverse Simpson with peak diversity at the greatest disturbance frequency treatment. These results demonstrate that the dynamics of a microbial community can vary depending on substrate and the disturbance frequency, and may potentially explain the variety of diversity-disturbance relationships observed in microbial ecosystems.

A new ferrocene derivative blocks K-Ras localization and function by oxidative modification at His95.

Ras proteins are membrane-bound GTPases that regulate essential cellular processes at the plasma membrane (PM). Constitutively active mutations of K-Ras, one of the three Ras isoforms in mammalian cells, are frequently found in human cancers. Ferrocene derivatives, which elevate cellular reactive oxygen species (ROS), have shown to block the growth of non-small cell lung cancers harboring oncogenic mutant K-Ras. Here, we tested a novel ferrocene derivative on the growth of pancreatic ductal adenocarcinoma and non-small cell lung cancer. Our compound, which elevated cellular ROS levels, inhibited the growth of K-Ras-driven cancers, and abrogated the PM binding and signaling of K-Ras in an isoform-specific manner. These effects were reversed upon antioxidant supplementation, suggesting a ROS-mediated mechanism. We further identified that K-Ras His95 residue plays an important role in this process, and it is putatively oxidized by cellular ROS. Together, our study demonstrates that the redox system directly regulates K-Ras/PM binding and signaling via oxidative modification at the His95, and proposes a role of oncogenic mutant K-Ras in the recently described antioxidant-induced growth and metastasis of K-Ras-driven cancers.

Laparoscopic iliac and iliofemoral lymph node resection for melanoma.

Regional lymphadenectomy in the iliac and groin, originally devised by Basset in 1912, is performed for the treatment of melanoma metastatic to this lymphatic basin. Laparoscopic iliac node dissection may be a valuable management option because it allows performance of the same procedure as in open surgery but with significant benefits such as decreased operative morbidity due to decreased surgical trauma, less violation of the abdominal muscles or the inguinal ligament, reduced postoperative pain, and increased patient satisfaction with the cosmetic appearance. The authors' approach makes use of a laparoscopic technique to offer an alternative to traditionally described lymph node dissection for melanoma. A review of the literature showed few laparoscopic approaches in this context. Jones et al. do not perform the resection en bloc and do not address the iliofemoral lymph node dissection with a combined retroperitoneal technique such as the current authors use. Two authors in the literature use laparoscopy through a transperitoneal approach, with a piecemeal removal of nodes. Delman et al. limit their technique to the inguinal and high femoral basin alone. The video demonstrates the novel use of a laparoscopic method to harvest iliac lymph nodes in combination with a minimally invasive approach to groin dissection for metastatic melanoma. After a laparoscopic resection of these nodes, the authors deliver the iliac nodal contents through the groin using a minimally invasive approach. This approach is highly beneficial to the patient. He is able to leave the hospital significantly earlier than he would have after a traditional open procedure. He can return to his job as a car mechanic within 1 week and is metastasis free at the 9-month follow-up assessment without evidence of lymphocele formation. The authors do not believe that this technique has any significant implication for lymphocele formation compared with an open procedure because in essence, the same resection is being performed. A larger prospective series is necessary to determine lymphocele outcomes.

A novel cranioplasty technique incorporating cancellous femoral bone and recombinant bone morphogenic protein 2.

Large calvarial defects in the setting of chronic infection and limited autologous donor sites present challenging problems for the reconstructive surgeon. We report on a novel osteogenic implant as a potential calvarial reconstruction solution. Two patients with an extensive history of severe traumatic brain injury and multiple cranial operations desired delayed calvarial reconstruction subsequent to removal of infected acrylic and titanium implants. These patients underwent harvesting of cancellous femoral bone and bone marrow, which was placed between 2 layers of recombinant bone morphogenic protein 2 impregnated in acellular collagen sponges and an outer layer of sturdily pliable Vicryl mesh to create a moldable osteogenic implant construct. The construct was molded into the shape of the defect and secured with sutures to the skull surrounding the defect. The osteogenic implant showed evidence of bone formation and maintained coverage over the original calvarial defect at 26 months postoperatively as well as subjective satisfaction by both patients and the senior surgeon. This technically straightforward technique with acceptable functional and aesthetic outcomes may be useful to reconstructing selected calvarial defects.