Vibrationally correlated calculations in polyspherical coordinates: Taylor expansion-based kinetic energy operators

The efficiency of quantum chemical simulations of nuclear motion can in many cases greatly benefit from the application of curvilinear coordinate systems. This is rooted in the fact that a set of smartly selected curvilinear coordinates may represent the motion naturally well, thus decreasing the couplings between motions in these coordinates. In this study, we assess the validity of different Taylor expansion-based approximations of kinetic energy operators in a (curvilinear) polyspherical parametrization. To this end, we investigate the accuracy as well as the numerical performance of the approximations in time-independent vibrational coupled cluster and full vibrational interaction calculations for several test cases ranging from tri- to penta-atomic molecules. We find that several of the proposed schemes reproduce the vibrational ground state and excitation energies to a decent accuracy, justifying their application in future investigations. Furthermore, due to the restricted mode coupling and their inherent sum-of-products form, the new approximations open up the possibility of treating large molecular systems with efficient vibrational coupled cluster schemes in general coordinates.

Large Variation in Heart Transplant Selection Practices During the COVID-19 Pandemic

Purpose

A growing proportion of transplant donors and recipients have a history of COVID infection. Transplant societies issued guidelines to support decisions regarding donor selection and recipient activation after COVID infection, but outcome data are still limited. This study sought to characterize heterogeneity in current clinical practice and opinions regarding cardiac donation after recipient or donor COVID infection.

Methods

An online survey was distributed to heart transplant clinicians through a professional society message board and social media. Responses were collected between September 29 and October 18, 2021.

Results

204 healthcare professionals from diverse geographic regions (North and South America, Europe, Middle East, Asia and Australia) completed the survey, including 143 (70%) transplant cardiologists, 42 (21%) cardiac surgeons and 19 (9%) other heart transplant clinicians. 80% of clinicians felt COVID vaccine should be mandatory before transplant. There was significant variation in clinical practice for donor acceptance and recipient management, including several scenarios directly addressed by society guidelines - see Figure 1 for a sample of responses.

Conclusion

There is significant variation in the clinical approach to common scenarios following donor or recipient COVID infection. This reflects continued uncertainty with post-transplant outcomes impacted by pre-transplant COVID infection. Granular outcome data are needed to better inform clinical decisions.

The Chloride Homeostasis of CA3 Hippocampal Neurons Is Not Altered in Fully Symptomatic Mepc2-null Mice

Rett syndrome (RTT) is an X-linked neurodevelopmental disorder caused mainly by mutations in the MECP2 gene. Mouse models of RTT show reduced expression of the cation-chloride cotransporter KCC2 and altered chloride homeostasis at presymptomatic stages. However, whether these alterations persist to late symptomatic stages has not been studied. Here we assess KCC2 and NKCC1 expressions and chloride homeostasis in the hippocampus of early [postnatal (P) day 30-35] and late (P50-60) symptomatic male Mecp2-null (Mecp2 ^-/y) mice. We found (i) no difference in the relative amount, but an over-phosphorylation, of KCC2 and NKCC1 between wild-type (WT) and Mecp2 ^-/y hippocampi and (ii) no difference in the inhibitory strength, nor reversal potential, of GABA _A -receptor-mediated responses in Mecp2 ^-/y CA3 pyramidal neurons compared to WT at any stages studied. Altogether, these data indicate the presence of a functional chloride extrusion mechanism in Mecp2 ^-/y CA3 pyramidal neurons at symptomatic stages.

Defying challenges: mid-term outcomes of international collaborations for a successful heart transplantation program in the middle east

Introduction

Heart transplantation (HTx) is a successful treatment strategy for advanced heart failure. Survival rates exceed those achieved by medical therapy alone. Lack of suitable donors and cultural perception remain obstacles for receiving this novel therapy.

Methods

Overcoming challenges we adopted a first-of-a-kind multicenter HTx program, collaborating between Cardiac Centers in India and the United Arab Emirates (UAE). Patients were worked up as part of our newly established HTx program in the UAE, then referred to India for successful HTx. All post HTx follow-up care was continued in the UAE thereafter.

Results

We assessed 10 HTx recipients, [90% male; mean age 34 yrs]. Five patients required inotropes while one LVAD support pre transplant. Our data outline short waiting-list time and excellent 3 years clinical outcomes.

All patients are maintained on Tacrolimus and Mycophenolate Mofetil. Two patient developed acute rejection (celluar and humoral) with graft dysfunction within 18 months.

Seventy percent had non-ischemic cardiomyopathy pre-transplant. Three acquired donor transmitted coronary vascular disease. One patient developed aggressive allograft vasculopathy requiring coronary artery bypass grafting. Acute kidney injury requiring renal replacement therapy occurred in 1 patient.

Conclusion

Defying logistic challenges, donor availability and long HTx waiting list times, we have established a successful multi-center new concept HTx program with excellent mid-term outcome result. Diverse genetic background is evident in the presence of early coronary vascular disease in young donor hearts, requiring extra care in donor screening. This international collaboration has a promising future for new programs in the Middle East.

Funding Acknowledgement

Type of funding source: None

The adipocyte hormone leptin sets the emergence of hippocampal inhibition in mice

Brain computations rely on a proper balance between excitation and inhibition which progressively emerges during postnatal development in rodent. γ-Aminobutyric acid (GABA) neurotransmission supports inhibition in the adult brain but excites immature rodent neurons. Alterations in the timing of the GABA switch contribute to neurological disorders, so unveiling the involved regulators may be a promising strategy for treatment. Here we show that the adipocyte hormone leptin sets the tempo for the emergence of GABAergic inhibition in the newborn rodent hippocampus. In the absence of leptin signaling, hippocampal neurons show an advanced emergence of GABAergic inhibition. Conversely, maternal obesity associated with hyperleptinemia delays the excitatory to inhibitory switch of GABA action in offspring. This study uncovers a developmental function of leptin that may be linked to the pathogenesis of neurological disorders and helps understanding how maternal environment can adversely impact offspring brain development.

Randomized clinical trial of biodegradeable intraluminal sheath to prevent anastomotic leak after stapled colorectal anastomosis

Background

Anastomotic leakage is a potential major complication after colorectal surgery. The C-seal was developed to help reduce the clinical leakage rate. It is an intraluminal sheath that is stapled proximal to a colorectal anastomosis, covering it intraluminally and thus preventing intestinal leakage in case of anastomotic dehiscence. The C-seal trial was initiated to evaluate the efficacy of the C-seal in reducing anastomotic leakage in stapled colorectal anastomoses.

Methods

This RCT was performed in 41 hospitals in the Netherlands, Germany, France, Hungary and Spain. Patients undergoing elective surgery with a stapled colorectal anastomosis less than 15 cm from the anal verge were eligible. Included patients were randomized to the C-seal and control groups, stratified for centre, anastomotic height and intention to create a defunctioning stoma. Primary outcome was anastomotic leakage requiring invasive treatment.

Results

Between December 2011 and December 2013, 402 patients were included in the trial, 202 in the C-seal group and 200 in the control group. Anastomotic leakage was diagnosed in 31 patients (7·7 per cent), with a 10·4 per cent leak rate in the C-seal group and 5·0 per cent in the control group (P = 0·060). Male sex showed a trend towards a higher leak rate (P = 0·055). Construction of a defunctioning stoma led to a lower leakage rate, although this was not significant (P = 0·095).

Conclusion

C-seal application in stapled colorectal anastomoses does not reduce anastomotic leakage. Registration number: NTR3080 (http://www.trialregister.nl/trialreg/index.asp).

High Frequency of Aneuploidy Defines Ulcerative Colitis-Associated Carcinomas: A Prognostic Comparison to Sporadic Colorectal Carcinomas

OBJECTIVE

Aneuploidy is an independent risk factor for forthcoming carcinogenesis in ulcerative colitis (UC). An inferior prognosis of patients with ulcerative colitis-associated colorectal cancer (UCC) compared with those with sporadic colorectal cancer (SCC) has been reported, but remains controversial. This prompted us to investigate if aneuploidy can be observed in UCCs as frequently as in their sporadic counterpart and if aneuploidy per se might be a driving feature of poor prognosis in UCC.

BACKGROUND DATA

We obtained clinical follow-up for 257 SCC patients (average observation time 57 months) and 31 UCC patients (51 months). Touch preparation slides or tissue sections were prepared of all 288 carcinomas for ploidy analysis.

METHODS

Ploidy status was assessed for 260 SCCs and 31 UCCs by image cytometry and correlated to clinical features. Survival data were analyzed using Kaplan-Meier estimates.

RESULTS

Aneuploidy was detected in 74.6% of SCCs and in all 31 UCCs. Logistic regression analysis yielded age (odds ratio [OR], 1.05; 95% CI, 1.02-1.09; P = 0.003) and aneuploidy (OR, 4.07; 95% CI, 1.46-11.36; P = 0.007) as independent prognostic factors for R0-resected patients devoid of metastases. Diploid SCCs had a more favorable 5-year survival (88.2%) than aneuploid SCCs (69.0%) and UCCs (73.1%) (P = 0.074).

CONCLUSIONS

UC-associated carcinomas presented aneuploidy at significantly higher frequency than sporadic colorectal carcinomas (P < 0.0006). UCCs and aneuploid SCCs share a similar prognosis inferior to that of diploid SCCs. Aneuploidy proved to be the strongest independent prognostic marker for R0-resected colorectal cancer patients overall.

Leptin potentiates GABAergic synaptic transmission in the developing rodent hippocampus

It is becoming increasingly clear that leptin is not only a hormone regulating energy homeostasis but also a neurotrophic factor impacting a number of brain regions, including the hippocampus. Although leptin promotes the development of GABAergic transmission in the hypothalamus, little is known about its action on the GABAergic system in the hippocampus. Here we show that leptin modulates GABAergic transmission onto developing CA3 pyramidal cells of newborn rats. Specifically, leptin induces a long-lasting potentiation (LLP-GABAA) of miniature GABAA receptor-mediated postsynaptic current (GABAA-PSC) frequency. Leptin also increases the amplitude of evoked GABAA-PSCs in a subset of neurons along with a decrease in the coefficient of variation and no change in the paired-pulse ratio, pointing to an increased recruitment of functional synapses. Adding pharmacological blockers to the recording pipette showed that the leptin-induced LLP-GABAA requires postsynaptic calcium released from internal stores, as well as postsynaptic MAPK/ERK kinases 1 and/or 2 (MEK1/2), phosphoinositide 3 kinase (PI3K) and calcium-calmodulin kinase kinase (CaMKK). Finally, study of CA3 pyramidal cells in leptin-deficient ob/ob mice revealed a reduction in the basal frequency of miniature GABAA-PSCs compared to wild type littermates. In addition, presynaptic GAD65 immunostaining was reduced in the CA3 stratum pyramidale of mutant animals, both results converging to suggest a decreased number of functional GABAergic synapses in ob/ob mice. Overall, these results show that leptin potentiates and promotes the development of GABAergic synaptic transmission in the developing hippocampus likely via an increase in the number of functional synapses, and provide insights into the intracellular pathways mediating this effect. This study further extends the scope of leptin's neurotrophic action to a key regulator of hippocampal development and function, namely GABAergic transmission.

Enhanced albumin uptake by rat tumors

Albumin dominates the nitrogen and energy resources in blood. However, only limited data is available on its accumulation and catabolism by tumors. This was caused by the lack of suitable radiolabels for long-term follow-up of protein catabolism in vivo. Conventional radiolabels like radioiodine are metabolically unstable. After lysosomal degradation diffusible tracer residues are rapidly released from catabolic sites, Tumors with high metabolic activity evade detection. To study the uptake of rat serum albumin (RSA) by tumors a conventional radioiodine label and two residualizing radiolabels were chosen. It is known that residualizing I-131-tyramine-deoxisorbitol and In-111-DTPA protein labels remain trapped at catabolic sites after lysosomal degradation of their carrier proteins. We were able to show by scintigraphy and after organ removal that a Walker-256 carcinosarcoma with a turner size of about 5% of the body weight accumulated more than 20% of the initially injected dose of a In-111-DTPA-RSA within 24 h. Tumor uptake rates for albumin exceeded those of the kidneys by about 4 times, and those of the liver by about 3 times. It was estimated that about one out of two albumin molecules trapped by an ovarian-342 tumor must have been degraded during 72 h. High uptake and degradation rates would make albumin an alternative nitrogen and energy source for these tumors. Although an unfavorable time-frame limits the use of residualizingly labeled albumin for scintigraphic tumor diagnosis in man, albumin might be an interesting carrier for delivering covalently attached chemotherapeutic agents into tumors by an alternative lysosomal route.

Impact of donor left ventricular hypertrophy on survival after heart transplant

Left ventricular hypertrophy (LVH) of the donor heart is believed to increase the risk of allograft failure after transplant. However this effect is not well quantified, with variable findings from single-center studies. The United Network for Organ Sharing database was used to analyze the effect of donor LVH on recipient survival. Three cohorts, selected in accordance with the American Society of Echocardiography guidelines, were examined: recipients of allografts without LVH (<1.1 cm), with mild LVH (1.1-1.3 cm) and with moderate-severe LVH (≥ 1.4 cm). The study group included 2626 patients with follow-up of up to 3.3 years. Mild LVH was present in 38% and moderate-severe LVH in 5.6% of allografts. Predictors of mortality included a number of donor and recipient characteristics, but not LVH. However, a subgroup analysis showed an increased risk of death in recipients of allografts with LVH and donor age >55 years, and in recipients of allografts with LVH and ischemic time ≥ 4 h. In the contemporary era, close to half of all transplanted allografts demonstrate LVH, and survival of these recipients is similar to those without LVH. However, the use of allografts with LVH in association with other high-risk characteristics may result in increased mortality.

Postoperative pulmonary complications after gynecologic surgery

OBJECTIVE

Investigate the frequency of, and risks for postoperative pulmonary complications after surgery for non-malignant gynecologic disorders.

METHOD

A retrospective component included medical record data for one year. A prospective component enrolled 300 patients consecutively who were scheduled for gynecologic surgeries.

RESULT

Postoperative pulmonary complications occurred in 1.22% of 328 open abdominal procedures in the retrospective study, and 2.16% of 232 in the prospective study. Pooling the data yielded a frequency estimate of 1.61%. Mean hospital length of stay (pooled data) increased 1.75 days in those with postoperative pulmonary complications. Smoking was the only significant risk factor (relative risk=3.9 using pooled data).

CONCLUSION

Postoperative pulmonary complications after surgery for non-malignant gynecologic disorders are infrequent but increase hospital length of stay. Smokers are at increased risk.

The angle of internal flow as an indicator of filling and drug release properties of capsule formulations

The cohesiveness of size fractions of acetylsalicylic acid and lactose alone and in various combinations has been determined by estimation of the rate of decrease in volume as a function of tamping under standard conditions. The cohesiveness was quantified in terms of empirically derived characteristic, the angle of internal flow phi. The value of phi was found to decrease with the particle size of acetylsalicylic acid, but not lactose, and was found to be dependent on the relative proportion and particle sizes of acetylsalicylic acid and lactose when blends of powder were studied. The value of the time for 50% of the drug content to be released from a hard gelatin capsule in an in-vitro dissolution test, T50, was found to decrease with decreasing values of omega for capsules containing acetylsalicylic acid alone. For capsules containing powder blends there was no consistent relationship between the value of T50 and phi.

Chromogranin A (CGA) in the gastro-entero-pancreatic (GEP) endocrine system. I. CGA in the mammalian endocrine pancreas

Chromogranin A (CGA), a protein at first detected in the adrenal medulla, has recently been found also in other organs, e.g. the endocrine pancreas. However, immunohistochemical findings concerning the cellular source of pancreatic CGA were controversial. Therefore, the endocrine pancreas of 10 mammalian species (man, tupaia, mole, cat, dog, pig, guinea pig, rabbit, rat) was investigated immunohistochemically for CGA-like immunoreactivities on serial semithin plastic sections using a high-titer polyclonal antiserum against bovine CGA. The results show that basically all pancreatic endocrine cell types are CGA-immunoreactive; however, every species has its own pattern of CGA-immunoreactive cell types. Other findings of the present studies indicate that the physiological function of CGA in pancreatic endocrine cells is related to the storage mechanisms of peptide hormones. Finally, a methodological approach is given to obtain not only qualitative but also semi-quantitative data during immunohistochemical investigations.

The prediction of the bulk densities of powder mixtures, and its relationship to the filling of hard gelatin capsules

From measurements of the properties of individual components, it has been found possible to predict the maximum tapped bulk density of two component mixtures of a range of particle size fractions of acetylsalicylic acid and lactose in varying proportions. This has been extended to the prediction of bulk density of such mixtures when filled into hard gelatin capsules by a system which results in the powders existing at the maximum tapped bulk density. Consequently the capsule fill weight can also be predicted for such systems. The method is less satisfactory for the prediction of the bulk density and capsule fill weight, when the capsules are filled by a process involving compression of the powder within the capsule shell.

The influence of drug and diluent particle size on the in vitro release of drug from hard gelatin capsules

The in vitro release of a drug from capsules containing different proportions of controlled particle size fractions of acetylsalicylic acid and lactose, has been assessed in terms of the time for 50% of the drug content of the capsule to be released into solution during a dissolution test (T50), and by a standard disintegration test. In general the two types of test gave closely related responses although some discrepancies existed with certain systems. For capsules containing only the drug, the value of T50 increased as the particle size of the drug decreased. The addition of lactose generally reduced the T50 value, the extent of the reduction showing greater dependence on the proportion of lactose added than its particle size. Capsule formulations containing 80% w/w of lactose had values of T50 which were independent of drug or diluent particle size. Capsule formulations containing lower proportions of lactose usually had an optimum combination of particle size fractions of drug and diluent for maximum drug release. The relationship between drug release and the porosity within the capsule was dependent on the particle size of the drug.