Good outcomes for arteriovenous fistula with buttonhole cannulation for chronic hemodialysis in children and adolescents.

BACKGROUND: Arteriovenous fistula (AVF) is the preferred access for chronic hemodialysis (HD) in children and adolescents, but central venous catheter use is still high. METHODS: Retrospective chart review of children and adolescents with AVF created between January 2003 and December 2015 was performed to assess primary failure (PF), maturation time, functional primary and functional cumulative patency, and potential risk factors for AVF dysfunction. RESULTS: Ninety-nine AVF were created in 79 patients (54% male; 7-24 years; 16-147 kg) by experienced surgeons. Duplex ultrasonography vein mapping was used to assist with site selection. PF occurred in 17 AVF (17%) in 14 patients. Patient age, gender, ethnicity, underlying disease, time on dialysis, and AVF site were not associated with PF or patency. Coagulation abnormality was positively associated with PF (p = 0.03). Function was achieved in 82 AVF (83%) in 77 patients (97%). Median maturation time was 83 days (range 32-271). AVF were accessed via buttonholes. Functional primary patency was 95%, 84%, and 53% at 1, 2, and 5 years. Overall 1- and 2-year functional cumulative patency was 95%, but lower for small patients 16-30 kg (88%) and those greater than 80 kg (91%). The 5-year patency rate was 80%, but significantly lower for 16-30 kg (59%) and greater than 80 kg (55%). Risk analysis showed significantly better patency for 31-45 kg and 46-80 kg groups (p < 0.01), non-obese BMI (p = 0.01), and buttonhole self-cannulation (p = 0.03). CONCLUSIONS: This study provides more information about successful AVF with buttonhole cannulation in pediatric hemodialysis patients lending additional support for AVF use in pediatrics. A higher resolution version of the Graphical abstract is available as Supplementary information.

Assessing the Binding of Venoms from Aquatic Elapids to the Nicotinic Acetylcholine Receptor Orthosteric Site of Different Prey Models.

The evolution of an aquatic lifestyle from land dwelling venomous elapids is a radical ecological modification, bringing about many evolutionary changes from morphology to diet. Diet is an important ecological facet which can play a key role in regulating functional traits such as venom composition and prey-specific targeting of venom. In addition to predating upon novel prey (e.g., fish, fish eggs and invertebrates), the venoms of aquatic elapids also face the challenge of increased prey-escape potential in the aquatic environment. Thus, despite the independent radiation into an aquatic niche on four separate occasions, the venoms of aquatic elapids are evolving under convergent selection pressures. Utilising a biolayer interferometry binding assay, this study set out to elucidate whether crude venoms from representative aquatic elapids were target-specific to the orthosteric site of postsynaptic nicotinic acetylcholine receptor mimotopes of fish compared to other terrestrial prey types. Representatives of the four aquatic lineages were: aquatic coral snakes representative was Micrurus surinamensis;, sea kraits representative was Laticauda colubrina; sea snakes representatives were two Aipysurus spp. and eight Hydrophis spp; and water cobras representative was Naja annulata. No prey-specific differences in crude venom binding were observed from any species tested, except for Aipysurus laevis, which showed slight evidence of prey-potency differences. For Hydrophis caerulescens, H. peronii, H. schistosus and M. surinamensis, there was a lack of binding to the orthosteric site of any target lineage. Subsequent testing on the in vitro chick-biventer cervicis muscle preparation suggested that, while the venoms of these species bound postsynaptically, they bound to allosteric sites rather than orthosteric. Allosteric binding is potentially a weaker but faster-acting form of neurotoxicity and we hypothesise that the switch to allosteric binding is likely due to selection pressures related to prey-escape potential. This research has potentially opened up the possibility of a new functional class of toxins which have never been assessed previously while shedding light on the selection pressures shaping venom evolution.

Widely-tunable, narrow-linewidth III-V/silicon hybrid external-cavity laser for coherent communication.

We demonstrate a III-V/silicon hybrid external cavity laser with a tuning range larger than 60 nm at the C-band on a silicon-on-insulator platform. A III-V semiconductor gain chip is hybridized into the silicon chip by edge-coupling the silicon chip through a Si3N4 spot size converter. The demonstrated packaging method requires only passive alignment and is thus suitable for high-volume production. The laser has a largest output power of 11 mW with a maximum wall-plug efficiency of 4.2%, tunability of 60 nm (more than covering the C-band), and a side-mode suppression ratio of 55 dB (>46 dB across the C-band). The lowest measured linewidth is 37 kHz (<80 kHz across the C-band), which is the narrowest linewidth using a silicon-based external cavity. In addition, we successfully demonstrate all silicon-photonics-based transmission of 34 Gbaud (272 Gb/s) dual-polarization 16-QAM using our integrated laser and silicon photonic coherent transceiver. The results show no additional penalty compared to commercially available narrow linewidth tunable lasers. To the best of our knowledge, this is the first experimental demonstration of a complete silicon photonic based coherent link. This is also the first experimental demonstration of >250 Gb/s coherent optical transmission using a silicon micro-ring-based tunable laser.

Factors Associated With Poor Child Motor Vehicle Restraint on the USA-Mexico Border.

Motor vehicle collisions (MVCs) are a significant cause of pediatric morbidity, particularly in low- to middle-income countries. We describe car seat use in children on the USA-Mexico border. A retrospective review was conducted for children 0-9 years old, admitted to the region's only Level I trauma center. Simultaneously, data were obtained from the SAFE KIDS database, a program that encourages car seat use through city checkpoints. There were 250 MVC admissions and nine fatalities in children 0-9 years old from 2010 to 2015. Nine percent of MVCs occurred in Mexico and 49% in El Paso, TX. Comparing trauma admissions to SAFE KIDS, there was some correlation between the location of MVCs and screening checkpoints (r = .50). There was a weaker correlation between injured children's neighborhoods and screening locations (r = .32). Only 37% of parents knew the crash history of the car seat and 3% were using a car seat previously involved in an MVC. While 96% of inspected children were placed appropriately in the backseat, 80% of children were found to be inappropriately restrained. Younger children more likely to be restrained (p < .05). Children from New Mexico and Mexico had the lowest rates of proper restraint and the highest injury severity scores. Proper use of car seats is a public health concern on the USA-Mexico border, and children are not properly restrained. Screening may be improved by focusing where at-risk children live and where most accidents occur. Restraint education is needed, particularly in New Mexico and Mexico.

Development of a predictive model for 6 month survival in patients with venous thromboembolism and solid malignancy requiring IVC filter placement.

PURPOSE: Our purpose was to develop a predictive model for short-term survival (i.e. <6 months) following inferior vena cava filter placement in patients with venous thromboembolism (VTE) and solid malignancy. METHODS: Clinical and laboratory parameters were retrospectively reviewed for patients with solid malignancy who received a filter between January 2009 and December 2011 at a tertiary care cancer center. Multivariate Cox proportional hazards modeling was used to assess variables associated with 6 month survival following filter placement in patients with VTE and solid malignancy. Significant variables were used to generate a predictive model. RESULTS: 397 patients with solid malignancy received a filter during the study period. Three variables were associated with 6 month survival: (1) serum albumin [hazard ratio (HR) 0.496, P < 0.0001], (2) recent or planned surgery (<30 days) (HR 0.409, P < 0.0001), (3) TNM staging (stage 1 or 2 vs. stage 4, HR 0.177, P = 0.0001; stage 3 vs. stage 4, HR 0.367, P = 0.0002). These variables were used to develop a predictive model to estimate 6 month survival with an area under the receiver operating characteristic curve of 0.815, sensitivity of 0.782, and specificity of 0.715. CONCLUSIONS: Six month survival in patients with VTE and solid malignancy requiring filter placement can be predicted from three patient variables. Our predictive model could be used to help physicians decide whether a permanent or retrievable filter may be more appropriate as well as to assess the risks and benefits for filter retrieval within the context of survival longevity in patients with cancer.

Numerical generation of laser-resonance phase noise for optical communication simulators.

We generate random numerical waveforms that mimic laser phase noise incorporating laser-resonance enhanced phase noise. The phase noise waveforms are employed in system simulators to estimate the resulting bit error rate penalties for differential quadrature phase shift keying signals. The results show that baudrate dependence of the bit error rate performance arises from laser-resonance phase noise. In addition, we show with supporting experimental results that the laser-resonance phase noise on the pumps in four-wave-mixing-based wavelength converters is responsible for large bit error rate floors.

Phase noise analysis of injected gain switched comb source for coherent communications.

We present experimentally and analytically the phase noise characterization of an externally injected gain switched comb source. The results reveal the residual high frequency FM noise in the comb lines, which stays unnoticed in the optical linewidth value but leads to an increased phase-error variance. The potential impact of the residual phase noise is investigated in a 10.7 GBaud optical DQPSK system where a 2 dB power penalty is recorded at BER of 10(-9). In a 10.7 GBaud digital coherent QPSK system no penalty is observed but with 5 GBaud 16-QAM format a 3 dBpenalty exists at the FEC limit of 4.4e-3.

Outcome of acute limb ischemia in cancer patients.

The optimal management strategy for acute limb ischemia (ALI) in patients with a concomitant malignancy is not well established. A very high mortality rate (83-100%) at 1 year has been reported in those who are treated surgically. Accordingly, a conservative management approach has been suggested as the main therapeutic modality. Our aim was to evaluate the survival outcomes of cancer patients treated for ALI at our cancer center. Cancer patients treated for ALI at the MD Anderson Cancer Center from 2001 to 2011 were included in this study. Overall survival and amputation-free survival rates were calculated. A total of 74 cancer patients with concomitant ALI were included in the study. Surgery was the most common therapy (36 patients; 49%). Percutaneous catheter-based interventions were used in 21 patients (28%). Eighteen patients (24%) received anticoagulation therapy only, and six patients (8%) received no therapy. The 30-day, 6-month, and 1-year overall survival rates were 80% (95% confidence interval [CI], 69% to 87%), 59% (95% CI, 47% to 69%), and 48% (95% CI, 36% to 59%), respectively. Eight patients (11%) underwent amputation. The 1-year amputation-free survival rate was 47% (95% CI, 35% to 58%). In conclusion, we did not find an invasive approach for the treatment of ALI in cancer patients to be associated with the very high mortality rates previously reported. In our opinion, the indications for surgery or catheter-based intervention in these patients should not differ from patients without cancer.

Measuring the correlation of two optical frequencies using four-wave mixing.

We use the physics of four-wave mixing to study the decorrelation of two optical frequencies as they propagate through different fiber delays. The phase noise relationship between the four-wave mixing components is used to quantify and measure the correlation between the two optical frequencies using the correlation coefficient. We show the difference in the evolution of decorrelation between frequency-dependent and frequency-independent components of phase noise.

Simple analytical model for low-frequency frequency-modulation noise of monolithic tunable lasers.

We employ simple analytical models to construct the entire frequency-modulation (FM)-noise spectrum of tunable semiconductor lasers. Many contributions to the laser FM noise can be clearly identified from the FM-noise spectrum, such as standard Weiner FM noise incorporating laser relaxation oscillation, excess FM noise due to thermal fluctuations, and carrier-induced refractive index fluctuations from stochastic carrier generation in the passive tuning sections. The contribution of the latter effect is identified by noting a correlation between part of the FM-noise spectrum with the FM-modulation response of the passive sections. We pay particular attention to the case of widely tunable lasers with three independent tuning sections, mainly the sampled-grating distributed Bragg reflector laser, and compare with that of a distributed feedback laser. The theoretical model is confirmed with experimental measurements, with the calculations of the important phase-error variance demonstrating excellent agreement.

Fangs and foliage: Unearthing the haemotoxic secrets of cannabis-dwelling rattlesnakes.

Despite a recent surge in high-throughput venom research that has enabled many species to be studied, some snake venoms remain understudied. The long-tailed rattlesnakes (Crotalus ericsmithi, C. lannomi, and C. stejnegeri) are one group where such research lags, largely owing to the rarity of these snakes and the hazardous areas, ripe with drug (marijuana and opium) production, they inhabit in Mexico. To fill this knowledge gap, we used multiple functional assays to examine the coagulotoxic (including across different plasma types), neurotoxic, and myotoxic activity of the venom of the long-tailed rattlesnakes. All crude venoms were shown to be potently anticoagulant on human plasma, which we discovered was not due to the destruction of fibrinogen, except for C. stejnegeri displaying minor fibrinogen destruction activity. All venoms exhibited anticoagulant activity on rat, avian, and amphibian plasmas, with C. ericsmithi being the most potent. We determined the mechanism of anticoagulant activity by C. ericsmithi and C. lannomi venoms to be phospholipid destruction and inhibition of multiple coagulation factors, leading to a net disruption of the clotting cascade. In the chick biventer assay, C. ericsmithi and C. lannomi did not exhibit neurotoxic activity but displayed potential weak myotoxic activity. BIRMEX® (Faboterápico Polivalente Antiviperino) antivenom was not effective in neutralising this venom effect. Overall, this study provides an in-depth investigation of venom function of understudied long-tailed rattlesnakes and provides a springboard for future venom and ecology research on the group.

Diseases of the thoracic aorta in women.

Women have now equaled or surpassed men in the number of cardiovascular deaths per year in published statistics. In 2006, according to the National Center for Health Statistics and the Center for Disease Control, cardiovascular disease was the cause of death in 428,906 women (35% of all deaths in women) and in 394,840 men (33% of all deaths in men). Of those numbers, it was estimated that 5506 women (0.4% of all deaths in women) and 7732 men (0.6%) died because of aortic aneurysm or dissection. Currently, aortic disease ranks as the 19th leading cause of death with reported increases in incidence. Historically, aortic disease is thought to affect men more frequently than women with a varying reported gender ratio. Gender bias has long been implicated as an important factor, but often overlooked, in the analysis and interpretation of cardiovascular diseases outcome, in part, because of the under-representation of women in clinical trials and studies. In this section, we provide an up-to-date review of the epidemiology and management of common diseases of the thoracic aorta, focusing on the differences and similarities in women and men.

Novel coherent self-heterodyne receiver based on phase modulation detection.

We propose a novel coherent self-heterodyne receiver structure based on phase modulation detection that potentially simplifies the front-end of a coherent optical receiver. The scheme has been demonstrated via simulations and experimentally for a 10 Gb/s DQPSK transmission system.

Effects of phase noise of monolithic tunable laser on coherent communication systems.

We investigate the effects of different phase noise processes of SGDBR laser on coherent systems. The SGDBR device operated well with QPSK modulation at 5 Gbaud, while the performance of 16-QAM was significantly degraded due to excess noise. The white FM noise mainly defines the ultimate performance of coherent reception, but the low frequency excess noise can potentially degrade the performance of systems that employ 16-QAM format at 5 Gbaud.

Retroperitoneal sarcoma presenting as acute renal failure, secondary to bilateral renal artery invasion.

Retroperitoneal sarcoma is a rare tumor accounting for 10 - 15% of all soft tissue malignancies with an incidence of 2.5 per million. Of those, liposarcoma is the most common type of retroperitoneal sarcoma accounting for 41% of cases. It usually presents late with vague symptoms such as abdominal discomfort or palpable mass. Vascular invasion is seen in 18% of retroperitoneal sarcomas but acute renal failure secondary to bilateral renal artery invasion/stenosis by these tumors has never been described yet. In this report, we describe the first case, to our knowledge, in the medical literature and discuss epidemiology, diagnosis, and management. Treatment is primarily surgical and the ability to completely resect the tumor is the most important predictor of survival. Active clinical trials are currently testing the use of adjunct chemotherapy and radiotherapy to improve morbidity and mortality.

An experimental investigation of laser scabbling on cement-based materials using nanosecond fiber laser.

In this study, the influence of a pulsed fiber laser of 250 W power with a spot size of 40 µm was successfully analyzed during scabbling of six types of cement mortar and three types of ultra-high-performance concrete (UHPC). Confocal microscopy on the surface of the scabbled samples elucidated the formation of three distinct zones: glassy layer (GL), partially melted zone (PMZ), and heat-affected zone (HAZ) with unique morphological appearances. The glassy layer exhibited bubble formation, whereas cracks were spotted alongside the scabbled area. The difference in scabbling depth between the beginning and end of the process was revealed by using 3D topography images. Moreover, the development of pores and the changes in the microstructure of each zone were observed by using scanning electron microscopy (SEM). Further energy dispersive X-ray (EDX) analysis also revealed significant changes in the percentage of silicon and calcium inside the glassy layer and non-processed zone (NPZ).

Isolation and Characterization of Two Postsynaptic Neurotoxins From Indian Cobra (Naja Naja) Venom.

The Indian Cobra (Naja naja) is among the "Big Four" responsible for most of the snakebite envenoming cases in India. Although recent proteomic studies suggest the presence of postsynaptic neurotoxins in N. naja venom, little is known about the pharmacology of these toxins. We isolated and characterized α-Elapitoxin-Nn2a (α-EPTX-Nn2a; 7020 Da) and α-Elapitoxin-Nn3a (α-EPTX-Nn3a; 7807 Da), a short-chain and long-chain postsynaptic neurotoxin, respectively, which constitute 1 and 3% of N. naja venom. α-EPTX-Nn2a (100-300 nM) and α-EPTX-Nn3a (100-300 nM) both induced concentration-dependent inhibition of indirect twitches and abolished contractile responses of tissues to exogenous acetylcholine and carbachol, in the chick biventer cervicis nerve-muscle preparation. The prior incubation of tissues with Indian polyvalent antivenom (1 ml/0.6 mg) prevented the in vitro neurotoxic effects of α-EPTX-Nn2a (100 nM) and α-EPTX-Nn3a (100 nM). The addition of Indian polyvalent antivenom (1 ml/0.6 mg), at the t90 time point, could not reverse the in vitro neurotoxicity of α-EPTX-Nn2a (100 nM). The in vitro neurotoxicity of α-EPTX-Nn3a (100 nM) was partially reversed by the addition of Indian polyvalent antivenom (1 ml/0.6 mg), as well as repeated washing of the tissue. α-EPTX-Nn2a displayed non-competitive antagonism of concentration-response curves to carbachol, with a pA2 of 8.01. In contrast, α-EPTX-Nn3a showed reversible antagonism of concentration-response curves to carbachol, with a pA2 of 8.17. De novo sequencing of α-EPTX-Nn2a and α-EPTX-Nn3a showed a short-chain and long-chain postsynaptic neurotoxin, respectively, with 62 and 71 amino acids. The important observation made in this study is that antivenom can reverse the neurotoxicity of the clinically important long-chain neurotoxin, but not the short-chain neurotoxin, from N. naja venom.

The Effect of Australian and Asian Commercial Antivenoms in Reversing the Post-Synaptic Neurotoxicity of O. hannah, N. naja and N. kaouthia Venoms In Vitro.

Despite antivenoms being the only established specific treatment for neuromuscular paralysis arising from snake envenoming, their ability to reverse the post-synaptic neurotoxicity in snake envenoming is poorly understood. We investigated the ability of five commercial antivenoms i.e., King cobra monovalent, Thai cobra monovalent, Thai neuro polyvalent, Indian polyvalent and Australian polyvalent antivenoms to reverse neurotoxicity induced by the venoms of King cobra (Ophiophagus hannah, 3 µg/mL), Indian cobra (Naja naja, 5 µg/mL) and Thai cobra (Naja kaouthia, 3 µg/mL) using the in vitro chick-biventer cervicis nerve-muscle preparation. All three venoms displayed post-synaptic neurotoxicity, which was prevented by all tested antivenoms (40 µL/mL) added to the bath prior to venom. All antivenoms partially reversed the established post-synaptic neuromuscular block after the addition of the three venoms during a 180 min observation period, but to varying degrees and at different rates. The neurotoxic effects of O. hannah venom recovered to a greater magnitude (based on twitch height restoration) and faster than the neurotoxicity of N. kaouthia venom, which recovered to a lower magnitude more slowly. The recovery of post-synaptic neurotoxicity by N. naja venom was hindered due to the likely presence of cytotoxins in the venom, which cause direct muscle damage. The observations made in this study provide further evidence that the commercial antivenoms are likely to actively reverse established α-neurotoxin-mediated neuromuscular paralysis in snake envenoming, and there is cross-neutralisation with different antivenoms.

Isolation and Pharmacological Characterization of α-Elapitoxin-Oh3a, a Long-Chain Post-Synaptic Neurotoxin From King Cobra (Ophiophagus hannah) Venom.

The King Cobra (Ophiophagus hannah) is the world's largest venomous snake and has a widespread geographical distribution throughout Southeast Asia. Despite proteomic studies indicating the presence of postsynaptic neurotoxins in O. hannah venom, there are few pharmacological investigations of these toxins. We isolated and characterized α-elapitoxin-Oh3a (α-EPTX-Oh3a; 7,938 Da), a long-chain postsynaptic neurotoxin, which constitutes 5% of O. hannah venom. α-EPTX-Oh3a (100-300 nM) caused concentration-dependent inhibition of indirect twitches and inhibited contractile responses of tissues to exogenous acetylcholine and carbachol, in the chick biventer cervicis nerve-muscle preparation. The prior incubation of tissues with Thai Red Cross Society King Cobra antivenom (1 ml/0.8 mg) prevented the in vitro neurotoxic effects of α-EPTX-Oh3a (100 nM). The addition of Thai Red Cross Society King Cobra antivenom (1 ml/0.8 mg), at the t90 time point partially reversed the in vitro neurotoxicity of α-EPTX-Oh3a (100 nM). Repeatedly washing the tissue did not allow significant recovery from the in vitro neurotoxic effects of α-EPTX-Oh3a (100 nM). α-EPTX-Oh3a demonstrated pseudo-irreversible antagonism of concentration-response curves to carbachol, with a pA2 of 8.99. De novo sequencing of α-EPTX-Oh3a showed a long-chain postsynaptic neurotoxin with 72 amino acids, sharing 100% sequence identity with Long neurotoxin OH-55. In conclusion, the antivenom is useful for reversing the clinically important long-chain α-neurotoxin-mediated neuromuscular paralysis.

Literature Review of Percutaneous Stenting for Palliative Treatment of Malignant Superior Vena Cava Syndrome (SVCS).

RATIONALE AND OBJECTIVES: To assess the efficacy and safety of percutaneous stenting for the palliative treatment of malignant superior vena cava syndrome (SVCS). METHODS AND MATERIALS: Literature review of retrospective studies was performed regarding direct procedural complications (fatal and non-fatal), clinical effectiveness, and patency rates (primary and secondary) of percutaneous transluminal stenting for the palliative treatment of malignant SVCS. Pooled rates and 95% confidence intervals were calculated for fatal complications, non-fatal complications, clinical effectiveness, primary patency, and secondary patency. Pooled rates were presented overall and by stent types (Wallstent, Nitinol stents, Steel stents and Stent Graft). Odds ratios and 95% confidence intervals were calculated to compare rates by stent type. RESULTS: Overall fatal complications rate was 1.46%, 95% CI [0.91 -2.23], non-fatal complications rate was 8.28%, 95% CI [6.91 -9.83], clinical effectiveness was 90.50%, 95% CI [88.86 -91.97], primary patency rate was 86.18%, 95% CI [84.06-88.12], secondary patency rate was 94.05 %, 95% CI [91.82 -95.82]. Primary patency rate of the Wallstent group was 83.38%, 95% CI [79.34 -86.90], and significantly higher for the Nitinol group 94.87%, 95% CI [87.40 -98.60], OR = 3.67, p = 0.01, and for the Stent Graft group 96.10%, 95% CI [89.00 -99.20], OR = 4.92, p = 0.01. Secondary patency rate for the Wallstent group was 93.33%, 95% CI [88.87 -96.40] and significantly lower for the Steel group 77.42%, 95% CI [58.90 -90.41], OR = 0.25, p = 0.01. CONCLUSION: Percutaneous stenting is a safe option for palliative treatment of patients with malignant SVCS with greater than 90% of patients experiencing immediate relief of symptoms, low rates of fatal complications (1.46%) and high patency rates (86.18% primary patency and 94.05% secondary patency).