Measurement of the Positive Muon Anomalous Magnetic Moment to 0.20 ppm.

We present a new measurement of the positive muon magnetic anomaly, a_{µ}≡(g_{µ}-2)/2, from the Fermilab Muon g-2 Experiment using data collected in 2019 and 2020. We have analyzed more than 4 times the number of positrons from muon decay than in our previous result from 2018 data. The systematic error is reduced by more than a factor of 2 due to better running conditions, a more stable beam, and improved knowledge of the magnetic field weighted by the muon distribution, ω[over ˜]_{p}^{'}, and of the anomalous precession frequency corrected for beam dynamics effects, ω_{a}. From the ratio ω_{a}/ω[over ˜]_{p}^{'}, together with precisely determined external parameters, we determine a_{µ}=116 592 057(25)×10^{-11} (0.21 ppm). Combining this result with our previous result from the 2018 data, we obtain a_{µ}(FNAL)=116 592 055(24)×10^{-11} (0.20 ppm). The new experimental world average is a_{µ}(exp)=116 592 059(22)×10^{-11} (0.19 ppm), which represents a factor of 2 improvement in precision.

Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm.

We present the first results of the Fermilab National Accelerator Laboratory (FNAL) Muon g-2 Experiment for the positive muon magnetic anomaly a_{µ}≡(g_{µ}-2)/2. The anomaly is determined from the precision measurements of two angular frequencies. Intensity variation of high-energy positrons from muon decays directly encodes the difference frequency ω_{a} between the spin-precession and cyclotron frequencies for polarized muons in a magnetic storage ring. The storage ring magnetic field is measured using nuclear magnetic resonance probes calibrated in terms of the equivalent proton spin precession frequency ω[over ˜]_{p}^{'} in a spherical water sample at 34.7 °C. The ratio ω_{a}/ω[over ˜]_{p}^{'}, together with known fundamental constants, determines a_{µ}(FNAL)=116 592 040(54)×10^{-11} (0.46 ppm). The result is 3.3 standard deviations greater than the standard model prediction and is in excellent agreement with the previous Brookhaven National Laboratory (BNL) E821 measurement. After combination with previous measurements of both µ^{+} and µ^{-}, the new experimental average of a_{µ}(Exp)=116 592 061(41)×10^{-11} (0.35 ppm) increases the tension between experiment and theory to 4.2 standard deviations.

Tree Stand-Related Injuries in Nonadmitted and Admitted Patients at a Level 2 Trauma Center in Michigan: 2015-2019.

INTRODUCTION: Tree stand-related injuries (TSRI) are more common than firearm-related injuries in hunters. Most previous studies on the topic used trauma databases that only include admitted patients. This study characterizes injury patterns found in nonadmitted and admitted TSRI patients presenting to a level 2 Michigan trauma center. TSRI prevention interventions are also discussed. METHODS: Cases were obtained through a retrospective chart review of the Henry Ford Allegiance Health trauma registry and EPSi cost-accounting database from 2015 to 2019. Keywords searched included fall, hunter, tree, tree stand, treestand, ICD 9 diagnosis (E884.9_Other accidental fall from one level to another), and ICD 10 diagnosis (W14.XXXA_Fall from tree, initial encounter). We analyzed age, sex, body mass index, injury severity score, disposition, alcohol use, injuries sustained, reported height of fall, and narrative of fall. RESULTS: Thirty-three patients were identified. Patient age was 45±13 y (mean±SD). All patients were male. Injury severity score for nonadmitted patients was 2±1 vs 13±11 in admitted patients. Thirty-three percent of cases were nonadmitted; 67% were admitted. The most common injuries sustained were spinal (33%) and lower extremity fractures (15%). The average yearly TSRI case rate was 5.73 per 10,000 hunters in the study area. CONCLUSIONS: Our study found that spinal and lower extremity fractures were the most common injuries sustained. One-third of our patients were nonadmitted and therefore not included in the Henry Ford Allegiance Health trauma registry. Some nonadmitted patients had significant injuries requiring specialist consultation, orthopedic braces, or outpatient surgery.

A prospective comparison of totally minimally invasive versus open Ivor Lewis esophagectomy.

The majority of esophagectomies in Western parts of the world are performed by a transthoracic approach reflecting the prevalence of adenocarcinoma of the lower esophagus or esophagogastric junction. Minimally invasive esophagectomy (MIE) has been reported in a variety of formats, but there are no series that directly compare totally minimally invasive thoracolaparoscopic 2 stage esophagectomy (MIE-2) with open Ivor Lewis (IVL). A prospective single-center cohort study of patients undergoing elective MIE-2 or IVL between January 2005 and November 2010 was performed. Short-term clinicopathologic outcomes were recorded using validated systems. One hundred and six patients (median age 66, range 36-85, 88 M : 18 F) underwent two-stage esophagectomy (53 MIE-2 and 53 IVL). Patient demographics (age, sex, body mass index, American Society of Anesthesiologists grade, tumor characteristics, neoadjuvant chemotherapy, and TNM stage) were comparable between the two groups. Outcomes for MIE-2 and IVL were comparable for anastomotic leak rates (5 [9%] vs. 2 [4%], P= 0.241), resection margin clearance (R0) (43 [81%] vs. 38 [72%], P= 0.253), median lymph node yield (19 vs. 18, P= 0.584), and median length of stay (12 [range 7-91] vs. 12 [range 7-101] days), respectively. Blood loss was significantly less for MIE-2 compared with IVL (median 300 [range 0-1250] mL vs. 400 [range 0-3000] mL, respectively, P= 0.021). MIE-2 in this series of selected patients supports its efficacy, when performed by an experienced minimally invasive surgical team. A well-designed multicenter trial addressing clinical effectiveness is now required.

A two-consultant approach is a safe and efficient strategy to adopt during the learning curve for laparoscopic Roux-en-Y gastric bypass: our results in the first 100 procedures.

BACKGROUND: Laparoscopic Roux-en-Y gastric bypass (LRYGBP) can be technically challenging. It is imperative that patient morbidity and mortality are minimized while teams are on the learning curve for this procedure. METHODS: This retrospective study evaluated the peri-operative risk of LRYGBP utilizing a two-consultant surgeon approach in a newly established bariatric service. 100 consecutive patients undergoing LRYGBP were included. Two consultants participated in each procedure. RESULTS: Median operative duration was 113 minutes (range 80-240) and fell with increasing experience [127 minutes (range 90-240) in cases 1-50 and 105 minutes (range 80-210) in cases 51-100; P=0.009]. Multivariate analysis found operation time correlated only with number of procedures performed (P<0.001). There were no conversions to laparotomy. Intra-operatively, 2 patients had hand-assisted completion of the jejuno-jejunostomy, and 2 underwent laparoscopic revision of the reconstruction. Postoperative complications were observed in 8 patients on the operative admission. Median stay was 4 days (range 3-7). 4 patients required readmission. There was no mortality. Percentage of excess BMI loss was 47%, 53% and 70% at 3, 6 and 12 months respectively. CONCLUSION: A learning curve for LRYGBP is evidenced in this series by reduction in operative time with increasing experience. Complication rates in line with large published series can be achieved by adopting a two-surgeon approach, which we propose as a safe method to adopt in the development of new bariatric services.

2016 WSES guidelines on acute calculous cholecystitis.

Acute calculus cholecystitis is a very common disease with several area of uncertainty. The World Society of Emergency Surgery developed extensive guidelines in order to cover grey areas. The diagnostic criteria, the antimicrobial therapy, the evaluation of associated common bile duct stones, the identification of "high risk" patients, the surgical timing, the type of surgery, and the alternatives to surgery are discussed. Moreover the algorithm is proposed: as soon as diagnosis is made and after the evaluation of choledocholitiasis risk, laparoscopic cholecystectomy should be offered to all patients exception of those with high risk of morbidity or mortality. These Guidelines must be considered as an adjunctive tool for decision but they are not substitute of the clinical judgement for the individual patient.

Erratum to: 2016 WSES guidelines on acute calculous cholecystitis.

[This corrects the article DOI: 10.1186/s13017-016-0082-5.].

A 31P-NMR study of the effects of reflow on the ischaemic rat heart.

(1) The recovery of perfused rat hearts experiencing various lengths of total global ischaemia was studied using 31P-NMR. Mechanical function was monitored by measuring left ventricular pressure. (2) Hearts exposed to a maximum of 14 min total global ischaemia regained stable contractile function on reperfusion. The concentration of phosphocreatine in these hearts rapidly exceeded its pre-ischaemic value while that of ATP rose very slowly. Pi fell on reflow to approximately its original level. These observations are interpreted as being the result of a rapid turnover of ATP stimulating phosphocreatine production by the mitochondrial isozyme of creatine kinase (ATP: creatine N-phosphotransferase, EC 2.7.3.2). (3) The recovery of intracellular pH on reperfusion does not depend upon the duration of ischaemia, nor on the pH or the percentage of ATP depletion at the end of the ischaemic period. This indicates that pH recovery is a flow-dependent phenomenon. (4) In non-recovering hearts, multiple Pi resonances are observed which arise from areas of differing myocardial pH. Phosphocreatine levels did not rise above 50% of their pre-ischaemic values. ATP levels remained depressed. This suggests that localized tissue necrosis only characterizes the failing situation.

The effects of insulin on myocardial metabolism and acidosis in normoxia and ischaemia. A 31P-NMR study.

1. The effect of insulin on the perfused rat heart during normoxia and total ischaemia was studied by 31P-NMR. 2. During normoxic perfusion, insulin increased the phosphocreatine to ATP ratio at the expense of Pi, when glucose was the substrate. No change was observed when acetate was used as the sole substrate. the intracellular pH (as measured from the position of the 2-deoxyglucose 6-phosphate resonance peak) was unaffected by insulin treatment. 3. Infusion of insulin prior to ischaemia caused an increase in the rate and extent of acidosis during the period of no flow while the rate of ATP depletion was decreased. 4. Freeze-clamped studies showed an increase in glycogen levels upon insulin treatment of the glucose perfused rat heart. During ischaemia, a decrease in glycogen content concomitant with an increase in lactate was observed. The accessibility of glycogen to phosphorylase during ischaemia is increased as a result of insulin treatment. The control of glycolysis during ischaemia is discussed with respect to the content and structure of glycogen in heart tissue.

A protective effect of insulin on reperfusing the ischaemic rat heart shown using 31P-NMR.

The effect on the recovery of mechanical function, ATP, phosphocreatine, Pi and pH of various lengths of total global ischaemia in the insulin-treated, perfused rat heart has been studied using 31P-NMR. Insulin-treated hearts recovered stable mechanical function after 18 min ischaemia when their intracellular pH was 6.0 and 70% of the pre-ischaemic ATP remained. Hearts perfused without insulin fail to recover after 18 min ischaemia, having an intracellular pH of 6.3 and 40% of ATP remaining (Bailey, I.A., Seymour, A.-M.L. and Radda, G.K. (1981) Biochim, Biophys. Acta 637, 1-7). Thus, ATP maintenance in ischaemia is more important to recovery on reperfusion than is maintaining intracellular pH. The importance of this observation in devising biochemical strategies for the clinical protection of the myocardium is discussed.

Metabolic consequences of positive inotropy in rat and guinea-pig hearts.

The metabolic and physiological responses of hearts from male rats and guinea-pigs to isoprenaline and SK&F 94120 (a phosphodiesterase III inhibitor), have been studied. Doses which gave similar chronotropic stimulation gave different inotropic responses. In both species, isoprenaline generated a greater increase in developed tension than SK&F 94120. With both drugs the inotropic response in the rat was less than than in the guinea-pig. 31P-NMR investigation of high-energy phosphate levels showed reduction in PCr concentration and an accompanying acidosis in the isoprenaline-perfused rat heart only. In both species, lactate production was stimulated by SK&F 94120 but not by isoprenaline. These results are discussed with reference to G-protein activation of ion channels and differences in Ca2+ handling by the two species.

Establishing a practical blood platelet threshold to avoid reporting spurious potassium results due to thrombocytosis.

BACKGROUND: Thrombocytosis is one of several pre-analytical factors which contribute to spuriously high serum potassium concentrations, yet there is little published data to guide analysts in the selection of a specific platelet count threshold above which serum potassium results become unreliable. We have studied the sensitivity and specificity of blood platelet count as a predictor of false elevations in potassium. METHODS: Paired serum and plasma potassium measurements together with full blood count were performed for 300 patients. All samples were stored at room temperature and analysed within 4 h of collection. The difference between serum and plasma potassium was plotted against blood platelet count. RESULTS: When the difference (serum-plasma) in potassium concentration was plotted against platelet count, there was a direct linear relationship. Blood platelet counts of >500 x 10(9)/L will detect elevations in serum relative to plasma potassium of >0.5 mmol/L, with a sensitivity of 71% and a specificity of 89%. CONCLUSION: It is recommended that where blood platelet count is above 500 x 10(9)/L, potassium measurements should be repeated using lithium heparin plasma. When serum potassium results of >5.4 mmol/L are obtained, it is our policy to check the platelet count if a sample is available before reporting results. If available and above 500 x 10(9)/L, potassium results are withheld and plasma requested.

Effects of vascular trauma and transient myocardial ischaemia on coronary venous prostaglandin levels in the dog.

The plasma concentrations of immunoreactive thromboxane B2 and 6-keto-prostaglandin-F1 alpha were determined in coronary venous blood sampled from open-chested, anaesthetised beagle dogs by local vein catheterisation. Thromboxane levels were high immediately following catheterisation (2.08 +/- 0.75 ng X ml-1, mean +/- SEM, n = 6) and fell over 25 min to 0.48 +/- 0.07 ng X ml-1. Initial trauma of the coronary veins (agitation of the catheter) produced a large but variable increase to 5.13 +/- 2.27 ng X ml-1 (0.1 greater than P greater than 0.05) within 2 min, but arterial trauma (repeated momentary occlusions) produced 0.4 +/- 0.03 ng X ml-1, a value not significantly different from control. After 7 min ischaemia an increase to 0.98 +/- 0.26 ng X ml-1 was detected (P less than 0.05). Reperfusion after 15 min ischaemia caused a fall to 0.43 +/- 0.09 ng X ml-1 at 2 min. In contrast, 6-keto-prostaglandin-F1 alpha levels varied little with trauma but increased to 0.64 +/- 0.14 ng X ml-1 (P less than 0.01) within 2 min ischaemia, remaining elevated. On reperfusion, levels fell to 0.27 +/- 0.06 ng X ml-1 (P less than 0.05) at 2 min, progressively increasing to 0.35 +/- 0.05 ng X ml-1 at 30 min. We conclude that intimal trauma of coronary veins induced thromboxane release and that the physical effects of venous sampling may contribute to apparent thromboxane release from ischaemic muscle. Although transient arterial and venous trauma had no significant effect on 6-keto-prostaglandin-F1 alpha, it is still possible that its release during ischaemia may follow prolonged arterial clamping.

Studies of isolated resistance vessels from offspring of essential hypertensive patients.

In order to investigate whether functional and morphological changes are present in the resistance vasculature before hypertension is established, isolated subcutaneous resistance vessels were studied from 21 young normotensive subjects with a family history of hypertension and 22 controls matched for age, sex, and weight. The vessels from the offspring of hypertensive patients displayed no morphological changes or differences in reactivity or sensitivity to the vasoconstrictor agonists norepinephrine, angiotensin II, serotonin, and vasopressin. In the presence of cocaine, however, vessels from offspring showed a significantly greater shift in sensitivity to norepinephrine, a phenomenon also observed in previous studies of vessels from hypertensive patients. The results suggest that in essential hypertension, while morphological and functional abnormalities of the resistance vasculature may develop as the blood pressure rises, a defect in neuroeffector activity is present before hypertension is established and may be a manifestation of abnormal sympathetic nervous system activity underlying the disease.

Non-invasive, kinetic measurements of [3H]nitrendipine binding to isolated rat myocytes by condensed phase radioluminescence.

The binding of 3H-labelled drug molecules to membranes of living cells gives rise to photon emission from tryptophan residues at proteinaceous binding sites. This phenomenon, called condensed phase radioluminescence, has been used to measure non-invasively the kinetics of [3H]nitrendipine binding and dissociation on the same samples of cultured beating cardiac myocytes. Signal arose only from bound drug molecules. Binding was monoexponential (tau = 5.5 min) as was dissociation (14.3 min). Preincubating cells with non-radioactive nifedipine reduced the amplitude and rate of [3H]nitrendipine but not of [3H]dihydroalprenolol binding. The potential uses of this phenomenon are discussed.

Approaches to detection of distantly related proteins by database searches.

The searching of protein databases as a method of identifying newly sequenced genes is commonplace in molecular biology laboratories. However, it is a procedure that is not usually formally taught to students, and method cookbooks discuss it only briefly. This article uses a single family of highly diverged uracil-DNA glycosylases, which fall into two distinct groups, to highlight some of the difficulties associated with identification of such proteins by database searching.

Exercise thallium imaging: location of perfusion abnormalities in single-vessel coronary disease.

Exercise-induced thallium defects were segmentally analyzed in four standard views (anterior, 40 degrees left anterior oblique, 60 degrees left anterior oblique, and left lateral) and correlated with the arteriographic findings in 49 patients with single-vessel disease (> 70% diameter narrowing). Defects in the septal (SEPT), anteroiseptal (ANT SEPT), and anterior (ANT) segments correlated (p < 0. 0005) with stenosis of the left anterior descending coronary artery (LAD). For LAD disease the ANT SEPT segment had the highest sensitivity (84%) and specificity (100%). Defects in the inferior (INF), posteroinferior (POST INF), and posterior (POST) segments correlated (p < 0.0005) with either right (RCA) or circumflex (LCX) stenosis. For RCA or LCX disease, the POST segment had the highest sensitivity (82%) and specificity (100%). The site of single-vessel coronary artery disease can be accurately predicted noninvasively by segmental analysis of thallium images in four anatomical projections.

Thallium-201 for myocardial imaging: appearance of the normal heart.

Thallium-201 myocardial perfusion images were obtained from 13 healthy adults after tracer administration both at rest and at maximal stress. On the rest-injected scan, tracer was seen in left ventricular myocardium, liver, and spleen. In two subjects with resting tachycardia, the right ventricular myocardium was slightly visualized after tracer injection at rest. When tracer was administered at stress, the left ventricular activity was more nearly homogeneous and the left ventricle was better defined on the scan. The left-ventricle-to-lung-background activity ratio increased from 2.4 at rest to 3.4 at stress. The right ventricular myocardium was seen on the stress-injected scan. Phantom studies, performed to define the optimum position for visualization of lesions, showed that small lesions were best defined when seen either en face or in tangent. Scans should be performed at stress whenever possible and multiple views are essential.

Face recognition in age-related maculopathy.

Patients with age-related maculopathy (ARM) complain frequently of difficulty with face recognition. The authors attempted to quantify the level of impairment by comparing face recognition with clinical tests of visual function, namely contrast sensitivity, grating acuity, letter-chart acuity, and word-reading acuity. For face recognition, we used 32 black-and-white photographs that had been cropped to remove the outline of hair so that identification was predominantly dependent on the facial features. The observer's distance from the screen on which the photographs were projected was varied. The angular size of the faces was indicated by the equivalent viewing distance (EVD). Four male and four female models were used, and for each model, there were four photographs with different facial expressions--happy, sad, angry, and afraid. For each photograph, the subject's task was to name the model and identify the facial expression. Threshold EVD (50%) was determined for correct identity recognition and expression recognition. For eight subjects all experimental procedures were repeated at a lower luminance level. For ARM subjects, increasing task complexity (grating/letters/words) substantially decreased resolution. Face-recognition abilities were most closely related to word-reading acuity when comparisons were made either across subjects or across luminances within subjects. Contrast sensitivity was associated poorly with face-recognition thresholds. In some subjects with more advanced ARM, identity recognition was substantially poorer than expression recognition.

Clinical grading and the effects of scaling.

In clinical practice, there has been a need to grade the magnitude or the severity of the functions and qualities that are assessed in the examination. It is popular to use a four-step grading scale to categorize the severity of clinical findings. The authors discuss clinical grading scales and their influence on the clinician's ability to detect change. These principles have been applied to grades or measures derived from either objective measuring instruments, subjective tests, or techniques in which the clinician makes subjective judgments. A hypothetical data set was used to show the problems associated with using grading scales that are too coarse. The authors presented a mathematic model that helps to estimate the benefits of using use of a finer scale. Data were presented from two separate studies, one on visual acuity measurement and the other on grading nuclear opacity, to show the advantages of using finer scales to enhance the sensitivity of clinical measurement. High levels of concordance between independent observations indicated that the grading scale was too coarse and that these scales needlessly reduced the clinician's ability to detect change in the parameter being assessed. For moderate sensitivity, the size of the scale increments should not exceed one standard deviation of the discrepancy so that the concordance of paired comparisons would not exceed 37%. For fine clinical sensitivity, the size of the scale increments should not exceed one third of the standard deviation of the discrepancy, in which case the concordance of paired comparisons would not exceed 13%. The theory and evidence presented here could prompt re-evaluations of common methods of clinical grading.