The "double-fired" gastro-jejunostomy as a form of improved efficiency during Whipple procedure.

BACKGROUND: Gastro-jejunostomy (GJ) after pylorus-resecting pancreatoduodenectomy (PD) is most commonly performed in a hand-sewn fashion. Intestinal stapled anastomosis are reported to be as effective as hand-sewn in terms of patency and risk of leakage in other indications. However, the use of a stapled gastro-jejunostomy hasn't been fully assessed in PD. The aim of the present technical report is to evaluate functional outcomes of stapled GJ during PD, its associated effect on operative time and related complications. METHODS: The institutional database for pancreatic duct adenocarcinoma (PDAC) was retrospectically reviewed. Pylorus resecting open PD without vascular or multivisceral resections were considered for the analysis. The incidence of clinically significant delayed gastric emptying (DGE from the International Stufy Group of Pancreatic Surgery (ISGPS) grade B and C), other complications, operative time and overall hospitalization were evaluated. RESULTS: Over a 10-years study period, 1182 PD for adenocarcinoma were performed and recorded in the database. 243 open Whipple procedures with no vascular and with no associated multivisceral resections were available and constituted the study population. Hand-sewn (HS) anastomosis was performed in 175 (72 %), stapled anastomosis (St) in 68 (28 %). No significant differences in baseline characteristics were observed between the two groups, with the exception of a higher rate of neoadjuvant chemotherapy in the HS group (74 % St vs. 86 % HS, p = 0.025). Intraoperatively, a significantly reduced median operative time in the St group was observed (248 min St vs. 370 mins HS, p < 0.001). Post-operatively, rates of clinically relevant delayed gastric emptying (7 % St vs. 14 % HS, p = 0.140), clinically relevant pancreatic fistula (10 % St, 15 % HS, p = 0.300), median length of stay (7 days for each group, p = 0.289), post-pancreatectomy hemorrhage (4.4 % St vs. 6.3 % HS, p = 0.415) and complication rate (22 % St vs. 34 % HS, p = 0.064) were similar between groups. However, readmission rates were significantly lower after St GJ (13.2 % St vs 29.7 % HS, p = 0.008). CONCLUSION: Our results indicate that a stapled GJ anastomosis during a standard Whipple procedure is non-inferior to a hand-sewn GJ, with a comparable rate of DGE and no increase of gastrointestinal related long term complications. Further, a stapled GJ anastomosis might be associated with reduced operative times.

High output power, single mode, and TEM00 operation of a multiple gain chip VECSEL using a twisted-mode configuration.

A vertical external cavity surface emitting laser (VECSEL) has been developed for a sodium guide star application. Stable single frequency operation with 21 W of output power near 1178 nm with multiple gain elements while lasing in the TEM00 mode has been achieved. Higher output power results in multimode lasing. For the sodium guide star application, the 1178 nm can be frequency doubled to 589 nm. The power scaling approach used involves using multiple gain mirrors in a folded standing wave cavity. This is the first demonstration of a high power single frequency VECSEL using a twisted-mode configuration and multiple gain mirrors located at the cavity folds.

Prospective evaluation of dietary and lifestyle pattern indices with risk of colorectal cancer in a cohort of younger women.

BACKGROUND: Although colorectal cancer (CRC) incidence in the USA is declining overall, its incidence is increasing among those younger than 50 years of age. The reasons underlying the increasing trend are largely unknown, although behavioral changes, such as unhealthy diet and lifestyle factors, may be partially responsible. DESIGN: A prospective cohort study included 94 217 women aged 26-45 years at baseline. Validated anthropometric measures and lifestyle information were self-reported biennially. Exposures were four recommendation-based dietary indices-the prime diet quality score and three plant-based dietary indices; and two mechanism-based indices-the empirical dietary and lifestyle index for hyperinsulinemia (EDIH and ELIH). We calculated hazard ratios (HRs) and 95% confidence intervals (CIs) for overall CRC and for early-onset (before age 50) and after age 50 CRC separately. RESULTS: We documented 332 cases of CRC during 24 years of follow-up (2 113 655 person-years), with an average age of 52 ± 7 years at diagnosis. Hyperinsulinemic dietary and lifestyle patterns were associated with a higher risk of CRC. Multivariable-adjusted HRs (95% CIs) comparing participants in the highest versus lowest quartile were: 1.67 for EDIH (95% CI: 1.15-2.44, P-trend = 0.01) and 1.51 for ELIH (95% CI: 1.10-2.08, P-trend = 0.01). Moreover, per 75% increment in rank, ELIH appeared to be a stronger risk factor for early-onset CRC (HR = 1.86, 95% CI: 1.12-3.07) than after age 50 CRC (HR = 1.20, 95% CI: 0.83-1.73, P-heterogeneity = 0.16). The four recommendation-based indices were not significantly associated with overall, early-onset, or after age 50 CRC risk (per 75% increment in rank, HRs ranged from 0.75 to 1.28). CONCLUSION: Dietary and lifestyle patterns contributing to hyperinsulinemia were associated with greater CRC risk in younger women. Moreover, the hyperinsulinemic lifestyle showed a suggestively stronger positive association with early-onset CRC risk, compared with after age 50 CRC. Our findings suggest that dietary and lifestyle interventions to reduce insulinemic potential may be effective for CRC prevention among younger women.

Selenoprotein DIO2 Is a Regulator of Mitochondrial Function, Morphology and UPRmt in Human Cardiomyocytes.

Members of the fetal-gene-program may act as regulatory components to impede deleterious events occurring with cardiac remodeling, and constitute potential novel therapeutic heart failure (HF) targets. Mitochondrial energy derangements occur both during early fetal development and in patients with HF. Here we aim to elucidate the role of DIO2, a member of the fetal-gene-program, in pluripotent stem cell (PSC)-derived human cardiomyocytes and on mitochondrial dynamics and energetics, specifically. RNA sequencing and pathway enrichment analysis was performed on mouse cardiac tissue at different time points during development, adult age, and ischemia-induced HF. To determine the function of DIO2 in cardiomyocytes, a stable human hPSC-line with a DIO2 knockdown was made using a short harpin sequence. Firstly, we showed the selenoprotein, type II deiodinase (DIO2): the enzyme responsible for the tissue-specific conversion of inactive (T4) into active thyroid hormone (T3), to be a member of the fetal-gene-program. Secondly, silencing DIO2 resulted in an increased reactive oxygen species, impaired activation of the mitochondrial unfolded protein response, severely impaired mitochondrial respiration and reduced cellular viability. Microscopical 3D reconstruction of the mitochondrial network displayed substantial mitochondrial fragmentation. Summarizing, we identified DIO2 to be a member of the fetal-gene-program and as a key regulator of mitochondrial performance in human cardiomyocytes. Our results suggest a key position of human DIO2 as a regulator of mitochondrial function in human cardiomyocytes.

Measures of body fatness and height in early and mid-to-late adulthood and prostate cancer: risk and mortality in The Pooling Project of Prospective Studies of Diet and Cancer.

BACKGROUND: Advanced prostate cancer etiology is poorly understood. Few studies have examined associations of anthropometric factors (e.g. early adulthood obesity) with advanced prostate cancer risk. PATIENTS AND METHODS: We carried out pooled analyses to examine associations between body fatness, height, and prostate cancer risk. Among 830 772 men, 51 734 incident prostate cancer cases were identified, including 4762 advanced (T4/N1/M1 or prostate cancer deaths) cases, 2915 advanced restricted (same as advanced, but excluding localized cancers that resulted in death) cases, 9489 high-grade cases, and 3027 prostate cancer deaths. Cox proportional hazards models were used to calculate study-specific hazard ratios (HR) and 95% confidence intervals (CI); results were pooled using random effects models. RESULTS: No statistically significant associations were observed for body mass index (BMI) in early adulthood for advanced, advanced restricted, and high-grade prostate cancer, and prostate cancer mortality. Positive associations were shown for BMI at baseline with advanced prostate cancer (HR = 1.30, 95% CI = 0.95-1.78) and prostate cancer mortality (HR = 1.52, 95% CI = 1.12-2.07) comparing BMI ≥35.0 kg/m2 with 21-22.9 kg/m2. When considering early adulthood and baseline BMI together, a 27% higher prostate cancer mortality risk (95% CI = 9% to 49%) was observed for men with BMI <25.0 kg/m2 in early adulthood and BMI ≥30.0 kg/m2 at baseline compared with BMI <25.0 kg/m2 in early adulthood and BMI <30.0 kg/m2 at baseline. Baseline waist circumference, comparing ≥110 cm with <90 cm, and waist-to-hip ratio, comparing ≥1.00 with <0.90, were associated with significant 14%-16% increases in high-grade prostate cancer risk and suggestive or significant 20%-39% increases in prostate cancer mortality risk. Height was associated with suggestive or significant 33%-56% risks of advanced or advanced restricted prostate cancer and prostate cancer mortality, comparing ≥1.90 m with <1.65 m. CONCLUSION: Our findings suggest that height and total and central adiposity in mid-to-later adulthood, but not early adulthood adiposity, are associated with risk of advanced forms of prostate cancer. Thus, maintenance of healthy weight may help prevent advanced prostate cancer.

Immediate and long-term impact of the COVID-19 pandemic on delivery of surgical services.

BACKGROUND: The ongoing pandemic is having a collateral health effect on delivery of surgical care to millions of patients. Very little is known about pandemic management and effects on other services, including delivery of surgery. METHODS: This was a scoping review of all available literature pertaining to COVID-19 and surgery, using electronic databases, society websites, webinars and preprint repositories. RESULTS: Several perioperative guidelines have been issued within a short time. Many suggestions are contradictory and based on anecdotal data at best. As regions with the highest volume of operations per capita are being hit, an unprecedented number of operations are being cancelled or deferred. No major stakeholder seems to have considered how a pandemic deprives patients with a surgical condition of resources, with patients disproportionally affected owing to the nature of treatment (use of anaesthesia, operating rooms, protective equipment, physical invasion and need for perioperative care). No recommendations exist regarding how to reopen surgical delivery. The postpandemic evaluation and future planning should involve surgical services as an essential part to maintain appropriate surgical care for the population during an outbreak. Surgical delivery, owing to its cross-cutting nature and synergistic effects on health systems at large, needs to be built into the WHO agenda for national health planning. CONCLUSION: Patients are being deprived of surgical access, with uncertain loss of function and risk of adverse prognosis as a collateral effect of the pandemic. Surgical services need a contingency plan for maintaining surgical care in an ongoing or postpandemic phase.

ANTECEDENTES: La pandemia en curso tiene un efecto colateral sobre la salud en la prestación de atención quirúrgica a millones de pacientes. Se sabe muy poco sobre el manejo de la pandemia y sus efectos colaterales en otros servicios, incluida la prestación de servicios quirúrgicos. MÉTODOS: Se ha realizado una revisión de alcance de toda la literatura disponible relacionada con COVID-19 y cirugía utilizando bases de datos electrónicas, páginas web de sociedades, seminarios online y repositorios de pre-publicaciones. RESULTADOS: Se han publicado varias guías perioperatorias en un corto período de tiempo. Muchas recomendaciones son contradictorias y, en el mejor de los casos, se basan en datos anecdóticos. A medida que las regiones con el mayor volumen de operaciones per cápita se ven afectadas, se cancela o difiere un número sin precedentes de operaciones. Ninguna de las principales partes interesadas parece haber considerado cómo una pandemia priva de recursos a los pacientes que necesitan una intervención quirúrgica, con pacientes afectados de manera desproporcionada debido a la naturaleza del tratamiento (uso de anestesia, quirófanos, equipo de protección, contacto físico y necesidad de atención perioperatoria). No existen recomendaciones sobre cómo reanudar la actividad quirúrgica. La evaluación tras la pandemia y la planificación futura deben incluir a los servicios quirúrgicos como una parte esencial para mantener la atención quirúrgica adecuada para la población también durante un brote epidémico. La prestación de servicios quirúrgicos, debido a su naturaleza transversal y a sus efectos sinérgicos en los sistemas de salud en general, debe incorporarse a la agenda de la OMS para la planificación nacional de la salud. CONCLUSIÓN: Los pacientes se ven privados de acceso a la cirugía con una pérdida de función incierta y riesgo de un pronóstico adverso como efecto colateral de la pandemia. Los servicios quirúrgicos necesitan un plan de contingencia para mantener la atención quirúrgica durante la pandemia y en la fase post-pandemia.

Coffee, tea, and caffeine intake and amyotrophic lateral sclerosis mortality in a pooled analysis of eight prospective cohort studies.

BACKGROUND AND PURPOSE: Caffeine is associated with a lower risk of some neurological diseases, but few prospective studies have investigated caffeine intake and risk of amyotrophic lateral sclerosis (ALS) mortality. We therefore determined associations between coffee, tea and caffeine intake, and risk of ALS mortality. METHODS: We conducted pooled analyses of eight international, prospective cohort studies, including 351 565 individuals (120 688 men and 230 877 women). We assessed coffee, tea and caffeine intake using validated food-frequency questionnaires administered at baseline. We used Cox regression to estimate study- and sex-specific risk ratios and 95% confidence intervals (CI) for ALS mortality, which were then pooled using a random-effects model. We conducted analyses using cohort-specific tertiles, absolute common cut-points and continuous measures of all exposures. RESULTS: During follow-up, 545 ALS deaths were documented. We did not observe statistically significant associations between coffee, tea or caffeine intake and risk of ALS mortality. The pooled multivariable risk ratio (MVRR) for ≥3 cups per day vs. >0 to <1 cup per day was 1.04 (95% CI, 0.74-1.47) for coffee and 1.17 (95% CI, 0.77-1.79) for tea. The pooled MVRR comparing the highest with the lowest tertile of caffeine intake (mg/day) was 0.99 (95% CI, 0.80-1.23). No statistically significant results were observed when exposures were modeled as tertiles or continuously. CONCLUSIONS: Our results do not support associations between coffee, tea or total caffeine intake and risk of ALS mortality.

No association between circulating concentrations of vitamin D and risk of lung cancer: an analysis in 20 prospective studies in the Lung Cancer Cohort Consortium (LC3).

Background: There is observational evidence suggesting that high vitamin D concentrations may protect against lung cancer. To investigate this hypothesis in detail, we measured circulating vitamin D concentrations in prediagnostic blood from 20 cohorts participating in the Lung Cancer Cohort Consortium (LC3). Patients and methods: The study included 5313 lung cancer cases and 5313 controls. Blood samples for the cases were collected, on average, 5 years before lung cancer diagnosis. Controls were individually matched to the cases by cohort, sex, age, race/ethnicity, date of blood collection, and smoking status in five categories. Liquid chromatography coupled with tandem mass spectrometry was used to separately analyze 25-hydroxyvitamin D2 [25(OH)D2] and 25-hydroxyvitamin D3 [25(OH)D3] and their concentrations were combined to give an overall measure of 25(OH)D. We used conditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for 25(OH)D as both continuous and categorical variables. Results: Overall, no apparent association between 25(OH)D and risk of lung cancer was observed (multivariable adjusted OR for a doubling in concentration: 0.98, 95% CI: 0.91, 1.06). Similarly, we found no clear evidence of interaction by cohort, sex, age, smoking status, or histology. Conclusion: This study did not support an association between vitamin D concentrations and lung cancer risk.

Propensity score-matched comparison of oncological outcomes between laparoscopic and open distal pancreatic resection.

BACKGROUND: Selected studies have reported improved outcomes in laparoscopic compared with open distal pancreatic resection. Concerns regarding failure to achieve proper oncological resection and compromised long-term outcomes remain. This study investigated whether postoperative outcomes and long-term survival after laparoscopic distal pancreatectomy are comparable to those after an open procedure. METHODS: This retrospective case-control study included patients who underwent distal pancreatectomy for resectable pancreatic adenocarcinoma between 2010 and 2013, identified from the National Cancer Database. Propensity score nearest-neighbour 1 : 1 matching was performed between patients undergoing laparoscopic or open distal pancreatectomy based on all relevant co-variables. The primary outcome was overall survival. RESULTS: Of 1947 eligible patients, 605 (31·1 per cent) underwent laparoscopic distal pancreatectomy. After propensity score matching, two well balanced groups of 563 patients each were analysed. There was no difference in overall survival at 3 years after laparoscopic versus open distal pancreatectomy (41·6 versus 36·0 per cent; hazard ratio 0·93, 95 per cent c.i. 0·77 to 1·12; P = 0·457). The overall conversion rate was 27·3 per cent (165 of 605). Patients who underwent laparoscopic distal pancreatectomy had outcomes comparable to those of patients who had an open procedure with regard to median time to chemotherapy (50 versus 50 days; P = 0·342), median number of nodes examined (12 versus 12; P = 0·759); 30-day mortality (1·2 versus 0·9 per cent; P = 0·562); 90-day mortality (2·8 versus 3·7 per cent; P = 0·403), 30-day readmission rate (9·6 versus 9·2 per cent; P = 0·838) and positive margin rate (14·9 versus 18·5 per cent; P = 0·110). However, median duration of hospital stay was shorter in the laparoscopic group (6 versus 7 days; P < 0·001). CONCLUSION: Laparoscopic distal pancreatectomy is an acceptable alternative to open distal pancreatectomy with no detriment to survival.

Knee pain and related health in the community study (KPIC): a cohort study protocol.

BACKGROUND: The incidence, progression and related risk factors for recent-onset knee pain (KP) remain uncertain. This study aims to examine the natural history of KP including incidence and progression and to identify possible phenotypes and their associated risk factors. METHODS: A prospective community-based cohort of men and women aged 40 years or over within the East Midlands region (UK) will be recruited via a postal questionnaire from their general practices. The questionnaire will enquire about: presence and onset of KP; pain severity (0­10 numerical rating scale (NRS)); pain catastrophizing and neuropathic-like pain (NP) using the painDETECT questionnaires (definite NP scores ≥19­38); risk factors for KP and/ or osteoarthritis (OA) (age, body mass index, constitutional knee alignment, nodal OA, index: ring finger length (2D4D) ratio); quality of life (SF12); and mental health (Hospital Anxiety and Depression Scale). Clinical assessments will be undertaken in a sample of 400 participants comprising three groups: early KP (≤3 year's duration), established KP (>3 years) and no KP. Assessments will include knee radiographs (standing semi-flexed and 30(0) skyline views); knee ultrasound (synovial effusion, hypertrophy, and Doppler activity); quantitative sensory testing; muscle strength (quadriceps, hip abductor, and hand-grip); balance; gait analysis (GAITrite); and biomarker sampling. A repeat questionnaire will be sent to responders at years 1 and 3. The baseline early KP group will undergo repeat assessments at year 1 (apart from radiographs) and year 3 (with radiographs). Any incident KP individuals identified at year 1 or 3 questionnaires will have clinical and radiographic assessments at the respective time points. DISCUSSION: Baseline data will be used to examine risk factors for early onset KP and to identify KP phenotypes. Subsequent prospective data, at least to Year 3, will allow examination of the natural history of KP and risk factors for incidence and progression. TRIAL REGISTRATION: The study was registered on the clinicaltrials.gov portal: NCT02098070) on the 14th of March 2014.

A practical guide to development of a successful robotic abdominal surgery program: The path to implementation.

The authors describe current situation in robotic assisted operations. The most important aspects of establishing a successful robotic program are patience and flexibility. The improved patient satisfaction, return to function, and decreased perioperative pain for patients and surgeons will be seen, but the road is long and requires careful navigation.Key Words: robot abdominal surgery - program development.

Dairy products and pancreatic cancer risk: a pooled analysis of 14 cohort studies.

Pancreatic cancer has few early symptoms, is usually diagnosed at late stages, and has a high case-fatality rate. Identifying modifiable risk factors is crucial to reducing pancreatic cancer morbidity and mortality. Prior studies have suggested that specific foods and nutrients, such as dairy products and constituents, may play a role in pancreatic carcinogenesis. In this pooled analysis of the primary data from 14 prospective cohort studies, 2212 incident pancreatic cancer cases were identified during follow-up among 862 680 individuals. Adjusting for smoking habits, personal history of diabetes, alcohol intake, body mass index (BMI), and energy intake, multivariable study-specific hazard ratios (MVHR) and 95% confidence intervals (CIs) were calculated using the Cox proportional hazards models and then pooled using a random effects model. There was no association between total milk intake and pancreatic cancer risk (MVHR = 0.98, 95% CI = 0.82-1.18 comparing ≥500 with 1-69.9 g/day). Similarly, intakes of low-fat milk, whole milk, cheese, cottage cheese, yogurt, and ice-cream were not associated with pancreatic cancer risk. No statistically significant association was observed between dietary (MVHR = 0.96, 95% CI = 0.77-1.19) and total calcium (MVHR = 0.89, 95% CI = 0.71-1.12) intake and pancreatic cancer risk overall when comparing intakes ≥1300 with <500 mg/day. In addition, null associations were observed for dietary and total vitamin D intake and pancreatic cancer risk. Findings were consistent within sex, smoking status, and BMI strata or when the case definition was limited to pancreatic adenocarcinoma. Overall, these findings do not support the hypothesis that consumption of dairy foods, calcium, or vitamin D during adulthood is associated with pancreatic cancer risk.

Reversible assembly of ß-sheet nanocrystals within caddisfly silk.

Nuclear magnetic resonance (NMR) and X-ray diffraction (XRD) experiments reveal the structural importance of divalent cation-phosphate complexes in the formation of ß-sheet nanocrystals from phosphorylated serine-rich regions within aquatic silk from caddisfly larvae of the species Hesperophyla consimilis. Wide angle XRD data on native caddisfly silk show that the silk contains a significant crystalline component with a repetitive orthorhombic unit cell aligned along the fiber axis with dimensions of 5.9 Å × 23.2 Å × 17.3 Å. These nanocrystalline domains depend on multivalent cations, which can be removed through chelation with ethylenediaminetetraacetic acid (EDTA). A comparison of wide angle X-ray diffraction data before and after EDTA treatment reveals that the integrated peak area of reflections corresponding to the nanocrystalline regions decreases by 15-25% while that of the amorphous background reflections increases by 20%, indicating a partial loss of crystallinity. (31)P solid-state NMR data on native caddisfly silk also show that the phosphorylated serine-rich motifs transform from a rigid environment to one that is highly mobile and water-solvated after treatment with EDTA. The removal of divalent cations through exchange and chelation has therefore caused a collapse of the ß-sheet structure. However, NMR results show that the rigid phosphorus environment is mostly recovered after the silk is re-treated with calcium. The (31)P spin-lattice (T1) relaxation times were measured at 7.6 ± 3.1 and 1 ± 0.5 s for this calcium-recovered sample and the native silk sample, respectively. The shorter (31)P T1 relaxation times measured for the native silk sample are attributed to the presence of paramagnetic iron that is stripped away during EDTA chelation treatment and replaced with diamagnetic calcium.

Mechanical and physical properties of recombinant spider silk films using organic and aqueous solvents.

Spider silk has exceptional mechanical and biocompatibility properties. The goal of this study was optimization of the mechanical properties of synthetic spider silk thin films made from synthetic forms of MaSp1 and MaSp2, which compose the dragline silk of Nephila clavipes. We increased the mechanical stress of MaSp1 and 2 films solubilized in both HFIP and water by adding glutaraldehyde and then stretching them in an alcohol based stretch bath. This resulted in stresses as high as 206 MPa and elongations up to 35%, which is 4× higher than the as-poured controls. Films were analyzed using NMR, XRD, and Raman, which showed that the secondary structure after solubilization and film formation in as-poured films is mainly a helical conformation. After the post-pour stretch in a methanol/water bath, the MaSp proteins in both the HFIP and water-based films formed aligned ß-sheets similar to those in spider silk fibers.

ß-Sheet nanocrystalline domains formed from phosphorylated serine-rich motifs in caddisfly larval silk: a solid state NMR and XRD study.

Adhesive silks spun by aquatic caddisfly (order Trichoptera) larvae are used to build both intricate protective shelters and food harvesting nets underwater. In this study, we use (13)C and (31)P solid-state NMR and wide angle X-ray diffraction (WAXD) as tools to elucidate molecular protein structure of caddisfly larval silk from the species Hesperophylax consimilis . Caddisfly larval silk is a fibroin protein based biopolymer containing mostly repetitive amino acid motifs. NMR and X-ray results provide strong supporting evidence for a structural model in which phosphorylated serine repeats (pSX)4 complex with divalent cations Ca(2+) and Mg(2+) to form rigid nanocrystalline ß-sheet structures in caddisfly silk. (13)C NMR data suggests that both phosphorylated serine and neighboring valine residues exist in a ß-sheet conformation while glycine and leucine residues common in GGX repeats likely reside in random coil conformations. Additionally, (31)P chemical shift anisotropy (CSA) analysis indicates that the phosphates on phosphoserine residues are doubly ionized, and are charge-stabilized by divalent cations. Positively charged arginine side chains also likely play a role in charge stabilization. Finally, WAXD results finds that the silk is at least 7-8% crystalline, with ß-sheet interplane spacings of 3.7 and 4.5 Å.

Nephila clavipes Flagelliform silk-like GGX motifs contribute to extensibility and spacer motifs contribute to strength in synthetic spider silk fibers.

Flagelliform spider silk is the most extensible silk fiber produced by orb weaver spiders, though not as strong as the dragline silk of the spider. The motifs found in the core of the Nephila clavipes flagelliform Flag protein are GGX, spacer, and GPGGX. Flag does not contain the polyalanine motif known to provide the strength of dragline silk. To investigate the source of flagelliform fiber strength, four recombinant proteins were produced containing variations of the three core motifs of the Nephila clavipes flagelliform Flag protein that produces this type of fiber. The as-spun fibers were processed in 80% aqueous isopropanol using a standardized process for all four fiber types, which produced improved mechanical properties. Mechanical testing of the recombinant proteins determined that the GGX motif contributes extensibility and the spacer motif contributes strength to the recombinant fibers. Recombinant protein fibers containing the spacer motif were stronger than the proteins constructed without the spacer that contained only the GGX motif or the combination of the GGX and GPGGX motifs. The mechanical and structural X-ray diffraction analysis of the recombinant fibers provide data that suggests a functional role of the spacer motif that produces tensile strength, though the spacer motif is not clearly defined structurally. These results indicate that the spacer is likely a primary contributor of strength, with the GGX motif supplying mobility to the protein network of native N. clavipes flagelliform silk fibers.

Phytoremediation of Lead-Contaminated Soil in the Westside of Atlanta, GA.

Phytoremediation has been explored as a cost-effective method to remediate soil Pb contamination. A greenhouse study was conducted to evaluate the efficacy of Vigna unguiculata, Brassica pekinensis, Gomphrena globose, and Helianthus annuus for removing and immobilizing Pb in soil collected from the Westside Lead Superfund site in Atlanta. Plants were cultivated in sampled soil with a Pb concentration of 515 ± 10 mg/kg for 60 days. Soils growing H. annuus were additionally treated with ethylenediaminetetraacetic acid (EDTA) (0.1 g/kg) or compost (20% soil blend) to assess their capabilities for enhancing phytoremediation. Mean post-phytoremediation Pb concentrations in the four plant species were 23.5, 25.7, 50.0, and 58.1 mg/kg dry weight (DW), respectively, and were substantially higher than 1.55 mg/kg DW in respective plant species grown in control soils with no Pb contamination. The highest Pb concentration, translocation factor, and biomass were found in V. unguiculate among four species without soil amendments. H. annuus treated with EDTA and compost resulted in a significant increase in the total Pb uptake and larger biomass compared to non-treated plants, respectively. Although this study found that V. unguiculata was the best candidate for Pb accumulation and immobilization among four species, soil remediation was limited to 54 mg/kg in a growing season. We find that it is critically important to perform phytostabilization in a secure manner, since Pb bioavailability of edible plant parts implies the potential risk associated with their unintentional consumption. Efficiently and effectively remediating Pb-contaminated soils in a low-cost manner needs to be further studied.

Cellular and molecular basis of deiodinase-regulated thyroid hormone signaling.

The iodothyronine deiodinases initiate or terminate thyroid hormone action and therefore are critical for the biological effects mediated by thyroid hormone. Over the years, research has focused on their role in preserving serum levels of the biologically active molecule T(3) during iodine deficiency. More recently, a fascinating new role of these enzymes has been unveiled. The activating deiodinase (D2) and the inactivating deiodinase (D3) can locally increase or decrease thyroid hormone signaling in a tissue- and temporal-specific fashion, independent of changes in thyroid hormone serum concentrations. This mechanism is particularly relevant because deiodinase expression can be modulated by a wide variety of endogenous signaling molecules such as sonic hedgehog, nuclear factor-kappaB, growth factors, bile acids, hypoxia-inducible factor-1alpha, as well as a growing number of xenobiotic substances. In light of these findings, it seems clear that deiodinases play a much broader role than once thought, with great ramifications for the control of thyroid hormone signaling during vertebrate development and metamorphosis, as well as injury response, tissue repair, hypothalamic function, and energy homeostasis in adults.

Magnesium intake, plasma C-peptide, and colorectal cancer incidence in US women: a 28-year follow-up study.

BACKGROUND: Laboratory studies suggest a possible role of magnesium intake in colorectal carcinogenesis but epidemiological evidence is inconclusive. METHOD: We tested magnesium-colorectal cancer hypothesis in the Nurses' Health Study, in which 85 924 women free of cancer in 1980 were followed until June 2008. Cox proportional hazards regression models were used to estimate multivariable relative risks (MV RRs, 95% confidence intervals). RESULTS: In the age-adjusted model, magnesium intake was significantly inversely associated with colorectal cancer risk; the RRs from lowest to highest decile of total magnesium intake were 1.0 (ref), 0.93, 0.81, 0.72, 0.74, 0.77, 0.72, 0.75, 0.80, and 0.67 (P(trend)<0.001). However, in the MV model adjusted for known dietary and non-dietary risk factors for colorectal cancer, the association was significantly attenuated; the MV RRs were 1.0 (ref), 0.96, 0.85, 0.78, 0.82, 0.86, 0.84, 0.91, 1.02, and 0.93 (P(trend)=0.77). Similarly, magnesium intakes were significantly inversely associated with concentrations of plasma C-peptide in age-adjusted model (P(trend)=0.002) but not in multivariate-adjusted model (P(trend)=0.61). Results did not differ by subsite or modified by calcium intakes or body mass index. CONCLUSION: These prospective results do not support an independent association of magnesium intake with either colorectal cancer risk or plasma C-peptide levels in women.