Based on superior image quality, more accurate gated images, and lower radiation exposure to patients, Technetium-99m (Tc-99m) based tracers are preferred over Thallium-201 for SPECT myocardial ...perfusion imaging. The two Tc-99m tracers, sestamibi and tetrofosmin, have many similar characteristics but there are differences in blood and liver clearance rates, as well as the recommended time after injection for imaging to achieve optimal image quality. Because published peer-reviewed studies examining optimal times between injection and imaging are limited, it can be difficult to identify evidence-based opportunities to optimize imaging protocols. Using systematic literature review methods, this study was designed to identify and consolidate the available evidence on the use of sestamibi compared to tetrofosmin for variable injection to imaging times in regard to test efficiency, including test length and re-scan rates, and image quality, including overall quality and cardiac to extra-cardiac ratios. The composite of this data shows that earlier imaging with tetrofosmin is equivalent to later imaging with sestamibi when assessing subjective image quality or when quantifying heart-to-extra-cardiac ratios. Image quality and heart-to-extra-cardiac ratios comparing early versus later imaging with tetrofosmin were comparable if not equivalent to each other. The equivalency of the imaging quality occurs with 15 minutes (on average) earlier imaging compared to sestamibi and 30 minutes compared to standard time tetrofosmin. The subjective findings of equivalent image quality are also shown with objective measurements of heart-to-extra-cardiac ratios. In this review, the significantly shorter injection-to-acquisition times with tetrofosmin compared to sestamibi resulted in better efficiency and less waiting times for patients; in addition, significantly higher re-scan rates with sestamibi compared to tetrofosmin due to hepatic activity contributed to better throughput with tetrofosmin.
The optimal cardiovascular evaluation prior to liver transplantation remains controversial and includes stress echocardiography, stress MPI, cardiac CTA, and coronary angiography. This study ...summarizes our experience of the past decade using SPECT MPI in patients with end-stage liver disease, including patient characteristics, stress testing protocols, test results, the need for repeat testing, and downstream testing.
All patients who underwent a clinically indicated stress SPECT MPI study as part of their pre-liver transplant evaluation from 2004 to 2014 were reviewed from the Nuclear Cardiology database. Results of perfusion imaging, repeat testing, subsequent angiography, and need for revascularization were reviewed.
A total of 2500 patients were referred for SPECT MPI, of those 111 had known CAD and 271 underwent more than one MPI study. Compared to other patients undergoing stress MPI, pre-liver transplant patients were younger, had fewer cardiac risk factors and lower prevalence of prior cardiac history, and used pharmacologic stress more often. During the study decade, patient age increased, prevalence of hypertension increased and smoking decreased, prevalence of known CAD increased, and the number of abnormal studies decreased. Abnormal perfusion results were present in 7.8% of pre-liver transplant patients compared to 34.3% of all other patients. In a multivariate model, age and lower ejection fraction were associated with an abnormal MPI result. Of the 64 patients who underwent subsequent invasive or non-invasive coronary angiography after an abnormal MPI, obstructive CAD was diagnosed in 25 patients (1.0%), non-obstructive CAD was diagnosed in 23 patients (0.9%), and normal coronaries found in 16 patients (0.6%); a total of 18 (0.7%) of these underwent coronary revascularization. The average time to repeat testing was 27.2 ± 17.9 months. In a multivariate model, younger age and exercise stress were associated with repeat testing. In only 17 patients out of 271 with a normal initial perfusion, the repeat study became abnormal. The use of stress-first imaging was successful in 80% of patients with a reduction in Tc-99m dose from 39.1 to 18.3 mCi.
Abnormal SPECT MPI results in candidates for liver transplantation are infrequent compared to non-liver transplant patients and the incidence of obstructive CAD on subsequent angiography even less. Repeat testing in those on the transplant waiting list after initial normal test results appears to be of limited value. Stress-first protocols may be considered for the majority of these patients to reduce testing time and radiation exposure.
In the blood from 63 rhesus monkeys (Macaca mulatta), transferrin, 6-phosphogluconate dehydrogenase, carbonic anhydrase II, phosphohexose isomerase, NADH diaphorase and leucocyte antigens were ...polymorphic. On the basis of these traits, paternity eliminations were determined for 29 offspring of 26 females from an established breeding group containing 8 sexually mature males. The dominance of the males was assessed by the directionality of the agonistic encounters. After examination of the results for two breeding seasons it was found that (1) the alpha male did not do all, or even most, of the successful mating and (2) there was evidence demonstrating increased reproductive success for males as a function of relative agonistic rank for the second but not the first of the 2 years.
To study the impact of the endometrial receptivity analysis (ERA) on live birth rates in frozen embryo transfer (FET) cycles.
Retrospective cohort study.
A single, large, university-affiliated ...infertility practice.
Autologous FET cycles between January 1, 2014, and June 30, 2019, were reviewed. Multiple covariates that impact outcomes were used for propensity score matching; 133 ERA patients were matched to 353 non-ERA patients. Patients were assigned to the ERA group if they had an ERA during treatment and underwent at least one “personalized” FET based on the ERA recommendations.
No interventions administered.
Live birth rates per cycle in the FET cycle after ERA compared with that of matched non-ERA patients.
The live birth rates for the ERA group, 49.62%, and the matched non-ERA group, 54.96%, (odds ratio 0.8074; 95% confidence interval, 0.5424–1.2018) were not significantly different, nor was a difference seen in subanalyses based on prior number of FETs or receptivity status.
The ERA identifies a patient’s putative window of implantation with the goal of improving synchrony with the embryo, thereby achieving higher live birth rates. This study used propensity score matching to control for multiple covariates in a heterogenous group of patients to compare live birth rates. There was no difference in the live birth rate in patients who underwent the ERA compared with that of those who did not.
El uso del puntaje de propensión de emparejamiento para evaluar el beneficio del análisis de receptividad endometrial en la transferencia de embriones congelados.
Estudiar el impacto del análisis de receptividad endometrial (ERA) en la tasa de recién nacido vivo en los ciclos de embriones congelados (FET).
Estudio de cohorte retrospectivo.
Una única y grande clínica de infertilidad asociada a una universidad.
Se revisaron los ciclos de FET autólogos entre el 1 de enero de 2014 y el 30 de junio de 2019. Se utilizaron múltiples covariables que impactan los resultados para el puntaje de propensión de emparejamiento; 133 pacientes con ERA fueron emparejadas con 353 pacientes sin ERA. Las pacientes fueron asignadas al grupo ERA si tuvieron un ERA durante el tratamiento y se sometieron al menos a una FET “personalizada” en base a las recomendaciones del ERA.
No se administraron intervenciones.
Tasa de recién nacido vivo por ciclo en FET después de ERA comparada con la de los pacientes emparejadas sin ERA.
Las tasas de recién nacido vivo para el grupo de ERA, 49.62%, y el grupo sin ERA emparejado, 54.96% (ratios de probabilidades 0.8074; 95% de intervalo de confianza, 0.5424 – 1.2018) no fueron significativamente diferentes, ni se vio una diferencia en los subanálisis basados en números previos de FET o el estado de la receptividad.
El ERA identifica la ventana de implantación putativa de una paciente con el objetivo de mejorar la sincronía con el embrión, logrando así mayores tasas de recién nacido vivo. Este estudio utilizó el puntaje de propensión de emparejamiento para controlar las múltiples covariables en un grupo heterogéneo de pacientes para comparar las tasas de recién nacido vivo. No hubo diferencia en la tasa de recién nacido vivo en pacientes con ERA en comparación con las que no se sometieron a un ERA.
This study reports on the performance of electrochemical-based low-cost sensors and their use in a community application. CairClip sensors were collocated with federal reference and equivalent ...methods and operated in a network of sites by citizen scientists (community members) in Houston, Texas and Denver, Colorado, under the umbrella of the NASA-led DISCOVER-AQ Earth Venture Mission. Measurements were focused on ozone (O₃) and nitrogen dioxide (NO₂). The performance evaluation showed that the CairClip O₃/NO₂ sensor provided a consistent measurement response to that of reference monitors (r² = 0.79 in Houston; r² = 0.72 in Denver) whereas the CairClip NO₂ sensor measurements showed no agreement to reference measurements. The CairClip O₃/NO₂ sensor data from the citizen science sites compared favorably to measurements at nearby reference monitoring sites. This study provides important information on data quality from low-cost sensor technologies and is one of few studies that reports sensor data collected directly by citizen scientists.
Eccentric muscle properties are not well characterized by the current paradigm of the molecular mechanism of contraction: the cross-bridge theory. Findings of force contributions by passive ...structural elements a decade ago paved the way for a new theory. Here, we present experimental evidence and theoretical support for the idea that the structural protein titin contributes to active force production, thereby explaining many of the unresolved properties of eccentric muscle contraction.
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