Micro-premature infants in New Jersey show improved mortality and morbidity from 2000-2018

BACKGROUND

Micro-premature newborns, gestational age (GA) ≤ 25 weeks, have high rates of mortality and morbidity. Literature has shown improving outcomes for extremely low gestational age newborns (ELGANs) GA ≤ 29 weeks, but few studies have addressed outcomes of ELGANs ≤ 25 weeks.

OBJECTIVE

To evaluate the trends in outcomes for ELGANs born in New Jersey, from 2000 to 2018 and to compare two subgroups: GA 23 to 25 weeks (E1) and GA 26 to 29 weeks (E2).

METHODS

Thirteen NICUs in NJ submitted de-identified data. Outcomes for mortality and morbidity were calculated.

RESULTS

Data from 12,707 infants represents the majority of ELGANs born in NJ from 2000 to 2018. There were 3,957 in the E1 group and 8,750 in the E2 group. Mortality decreased significantly in both groups; E1, 43.2% to 30.2% and E2, 7.6% to 4.5% over the 19 years. The decline in E1 was significantly greater than in E2. Most morbidities also showed significant improvement over time in both groups. Survival without morbidity increased from 14.5% to 30.7% in E1s and 47.2% to 69.9% in E2s. Similar findings held for 501-750 and 751-1000g birth weight strata.

CONCLUSIONS

Significant declines in both mortality and morbidity have occurred in ELGANs over the last two decades. These rates of improvements for the more immature ELGANs of GA 230 to 256 weeks were greater than for the more mature group in several outcomes. While the rates of morbidity and mortality remain high, these results validate current efforts to support the micro-premature newborn.

Levels of platelet derived extracellular vesicles in the left atrial appendage are higher in patients with permanent atrial fibrillation

Introduction

Atrial fibrillation (AF) is a frequent arrhythmic disease and one of the most important causes of thrombembolic disease due to intracardiac thrombus formation. The left atrial appendage has been identified as the structure, where thrombus formation typically takes place in AF patients. Previous studies have shown thrombus formation is more frequent in permanent, than in paroxysmal or persistent AF. Underlying causes for this finding, however, remain unclear. Recently, it has been shown, that large extracellular vesicles (Microvesicles, MVs) are mediators of platelet activation. The aim of this study is therefore to investigate if the AF subtype correlates with the regional abundance of platelet derived MVs in the left atrial appendage.

Methods and results

In order to address this question blood samples from 59 consecutive patients undergoing left and right atrial catheterization were collected from the right atrium (RA), the left atrium (LA) and the left atrial appendage (LAA). 49% of the patients had permanent AF, 34% had non-permanent AF and 17% had no history of AF. MVs were isolated from 150 μL citrate plasma by a four-step differential centrifugation protocol (20000g x 40 min as main pelleting step). The MVs were characterized by immunoblotting and nanoparticle tracking analysis. The size of the MVs ranged between 50 and 600 nm and the MVs were shown to carry typical markers such as Annexin V. For flowcytometric analysis and quantification, Calcein AM was used to identify vesicles and CD31-PE, CD41-APC, CD235a-PE-Cy7 were applied to differentiate between platelet-derived MVs (PMVs, CD41+ CD31+), endothelial cell-derived MVs (EMVs, CD41- CD31+) and Red blood cell-derived MVs (RMVs, CD235a+). Fluorescence minus one controls, a concentration row and detergent mediated degradation were used to confirm specific staining of MVs. Total MV numbers (Calcein + events) did not differ significantly between the three cardiac localizations. In the left atrial appendage, the proportion of PMV was significantly higher in permanent AF patients compared to non-permanent AF. EMV numbers only differed in the right atrium, where permanent AF patients exhibited significantly lower numbers of EMVs compared to no AF controls. No differences between the groups were detected for RMV.

Conclusion

In the present study, we found that PMV levels in the left atrial appendage correlate with the type of atrial fibrillation (permanent vs non-permanent). PMVs have been connected to platelet activation and thrombus formation. These results may help to better understand how different types of atrial fibrillation cause different rates of thrombus formation in the LAA.

PMV and EMV numbers by AF subtype

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Medical Faculty University Bonn

P5987Novel model of intensity graded murine wire-induced aortic valve stenosis mimics distinct stages of human aortic valve pathology

Background

Aortic valve stenosis (AS) is the most common valve disease requiring therapeutic intervention. Even though the incidence of AS has been continuously rising and AS is associated with significant morbidity and mortality, to date, no medical treatments have been identified that can modify disease progression. In fact, only invasive interventional or surgical replacement of severely diseased valves is recommended. This unmet medical need is likely attributed to the lack of a clear understanding of the molecular mechanism driving disease development. To investigate the pathophysiology leading to AS, reliable and reproducible animal models that mimic human pathophysiology are needed.

Hypothesis

Induction of a graded wire-induced aortic valve stenosis model in mice is feasible to reflect and study pathophysiological mechanisms underlying the progression of aortic valve stenosis.

Methods

We have tested and expanded the protocols of a novel wire-injury induced aortic valve stenosis mouse model. A spring coronary guide wire or a bare metal wire was used to apply shear stress to the aortic valve cusps with increasing intensity with ultrasound-guided monitoring in male 10 to 12-week-old C57Bl/6j mice. These protocols allowed the induction of distinct models with soft, moderate and intense wire injury. Functional analysis including maximum flow velocity (Vmax), ejection fraction, fractional shortening, left ventricular volumes, diameters and wall thickness were assessed by echocardiography before, one and four weeks after induction of aortic valve stenosis. Immunohistological analysis were performed after eight weeks (hematoxylin and eosin, von-Kossa staining, anti-CD68-staining).

Results

Upon moderate or severe injury, AS developed with a significant increase in aortic valve peak blood flow velocity. While moderate injury promoted solitary AS, severe-injury induced mixed aortic valve disease with concomitant mild to moderate aortic regurgitation. Only 5% of the mice who received a moderate injury displayed a mild aortic regurgitation. In the group of mice with intense injury 50% of the mice had a mild and 18,75% had a moderate aortic insufficiency. The changes in aortic valve function were reflected by dilation and hypertrophy of the left ventricle, as well as a decreased left ventricular ejection fraction after intense injury, while moderate injury did not show significant dilation of the left ventricle. Histological analysis revealed the three classic hallmarks of human disease with aortic valve thickening, increased macrophage infiltration and calcification eight weeks after injury.

Conclusion

Hereby, we demonstrate that the induction of a graded wire induced aortic valve stenosis model in mice mimicking relevant pathophysiological mechanisms is feasible to study disease progression. We extended existing protocols to induce moderate stenosis allowing to solely study aortic valve stenosis without relevant aortic valve regurgitation.

Acknowledgement/Funding

S.N. was funded by Else-Kröner-Fresenius-Foundation of the Medical Faculty of the University of Bonn

[The so-called specialist status from the viewpoint of jurisdiction of the German court of justice]

As long as the resident as a physician in training does not have the knowledge of a specialist, he has to be accompanied by a specialist (i.e., during surgical procedures). Is there a lack of such company, the onus of proof, that a failure is not due to the lack of specialist's quality, is on the side of the therapist. If this proof can be given, the question about specialist or not specialist is off the table (this is also true for the court of justice).

[Care responsibilities of the surgeon in the jurisdiction of the federal court]

Concerning his civil liability the surgeon's duty of care is determined by standards established in the first place by medicine. Jurisdiction has only control function. This task has to bring in line the protection of the patient's health from poor quality of medical treatment and "overtreatment" with the necessity and risks of specialisation and work sharing. The legal demands must not provoke overdiagnostics and defensive medicine themselves; in a limited manner they have to leave the choice of methods to the surgeon's authority.

The distribution and interaction of haemoglobin variants and the beta thalassaemia gene in Liberia

In a population survey in Liberia, West Africa, 12 major tribes were examined for the prevalence of Hb S, Hb C, and the beta thalassaemia (beta Thal) gene. Hb C is rare; Hb S and beta Thal occur in polymorphic frequencies. The distribution of both genes shows an inverse correlation. The beta Thal trait was diagnosed by quantitation of Hb A2 on DE 52-microchromatography. This method proved to be reliable and useful for mass screening.

Clostridium difficile in normal infants and sudden infant death syndrome: an association with infant formula feeding

Large numbers Clostridium difficile were found in the stools of two victims of sudden infant death syndrome (SIDS). This prompted a study of normal infants in the SIDS age group. Thirty-two infants were studied, using two selective culture techniques and two assays for bacterial products. Thirteen of the normal infants (39%) were found to carry C difficile, and fecal toxins were detected in eight of these, four with cytotoxin detectable at 10(-4) or higher dilution. Colonization was observed in one of 13 (7%) breast-fed babies and 12 of 17 (71%) of those whose primary milk source was infant formula (P less than .01). Fecal C difficile toxin was detected only in the latter group. The isolation of C difficile or its toxins in the stools of infants with SIDS, diarrhea, or even if large quantities of fecal cytotoxin are present.

[Oral effectiveness of the calcium-antagonist Ro 11-1781 (Tiapamil) in supraventricular and ventricular extrasystoles (author's transl)]

The effectiveness of the calcium-antagonist Ro 11-1781 (Tiapamil) was investigated in 23 patients with extrasystoles of different origin using continuous ECG recordings. Two 24-hour ECG recordings were registered without antiarrhythmic medication, one of these as a placebo period, and 3 during oral application of 3 x 200 mg/day Ro 11-1781, if the state of the health of the patients allowed it. No positive effects of Ro 11-1781 in supraventricular and ventricular extrasystoles were demonstrable, supported by 8 premature terminations of the study. The missing antiarrhythmic effectiveness of Ro 11-1781 corresponds to Verapamil in oral application.

Kinetics of dimerization of the Bence-Jones protein Au

The dimerization reactions of complete Bence-Jones protein Au (VC-Au) and of its variable fragment (V-Au) were compared in 0.2 M (ionic strength) sodium phosphate buffer, pH 6.8 at 20 degrees C. The dimerization constant for VC-Au (6.6 X 10(4) M-1) was slightly smaller than a previously published value for the fragment (1.1 X 10(5) M-1). The reaction enthalpies were positive for both processes. Temperature jump experiments exhibited two kinetic phases. The relaxation time of the fast phase as well as its concentration dependence and amplitude were almost identical for VC-Au and V-Au. Only small differences were observed in the slow phase. These close similarities between the reactions of the two proteins demonstrate that dimerization occurs mainly via interactions between the variable domains and that the constant domains interfere very little. From the observation of two relaxation times it follows that the dimerization mechanism for both VC-Au and A-Au must include at least three reacting species. Mechanisms with an isomerization between monomers in two conformational states and a single dimer species are excluded by the data. Alternative mechanisms with a single monomeric species but isomerization between dimers give a rather unsatisfactory fit. A good fit can be obtained if it is assumed that both monomers and dimers can exist in two states. Rate constants of the association and dissociation steps are of the order of 10(7) M-1 s-1 and 10(2) s-1. Isomerization rate constants are in the range of 10 s-1.

Kinetics of the interaction of alpha-chymotrypsin with trypsin kallikrein inhibitor (Kunitz) in which the reactive-site peptide bond Lys-15--Ala-16 is split

Modified trypsin kallikrein inhibitor (I*), with the reactive-site peptide bond Lys-15--Ala-16 split, reacts with alpha-chymotrypsin (E) via an intermediate X to the stable tetrahedral complex C:E + I in equilibrium X leads to C. Formation X constitutes a fast pre-equilibrium (equilibrium constant Kx = 7 X 10(-5) M, association rate constant kx = 4 X 10(3)M-1s-1) to the slow reaction X leads to C (rate constant kc = 2 X 10(-3) s-1), all values at pH 7.5. No intermediate X is observed when alpha-chymotrypsin reacts with I*-OMe in which the carboxyl group of Lys-15 is esterified by methanol. This observation as well as the different pH dependence of the overall association rate constants in the case of I* and I*-OMe indicate tha formation of X precedes formation of the acyl enzyme in the catalytic pathway. The data are compared to the similar results obtained with beta-trypsin and I* or I*-OMe.

Kinetics of binding of bovine trypsin-killikrein inhibitor (K unitz) in which the reactive-site peptide bond Lys-15--Ala-16 is cleaved, to alpha-chymotrypsin and beta-trypsin

Equilibrium measurements of the binding of reactive-site-cleaved (modified) bovine trypsin-kallikrein inhibitor (Kunitz) to alpha-chymotrypsin and beta-trypsin show a stoichiometric 1:1 association with high binding constants. At least in the case of chymotrypsin much evidence is presented that the reaction with modified inhibitor leads to the same complex as the reaction with virgin inhibitor does. The association rate constant of modified inhibitor with chymotrypsin at pH 7, 22.5 degrees C is 15.8 M-1 S-1. This is about 2 x 10(4) times slower than the binding of virgin inhibitor to that enzyme. In the analogous reaction of modified inhibitor with beta-trypsin, however, the association rate constant (1.2 x 10(4) M-1 s-1 at pH 6.9, 22.5 degrees C) is of about the same order of magnitude as it is in the reaction of virgin inhibitor and trypsin. These and analogous phenomena observed in the reactions of virgin and modified soybean trypsin inhibitor (Kunitz) with alpha-chymotrypsin and beta-trypsin suggest that the specificity of both inhibitors to trypsin is strongly reflected in the association rate constants of the modified forms. The dissociation rate constants of the complexes of trypsin-kallikrein inhibitor with chymotrypsin or with trypsin towards the modified inhibitor are estimated to be unmeasurably slow (half-life times of 45 or 1.5 x 10(4) years, respectively).

The effect of cleaving the reactive-site peptide bond Lys-15--Ala-16 on the conformation of bovine trypsin-kallikrein inhibitor (K unitz) as revealed by solvent-perturbation spectra, circular dichroism and fluorescence

Spectroscopic measurements of virgin bovine trypsin-kallikrein inhibitor and its modified species (in which the reactive-site peptide bond Lys-15--Ala-16 is split) indicate a conformational difference between both proteins. The inhibitor contains four tyrosines but no tryptophan. In the modified inhibitor a tyrosyl blue shift is seen in the difference absorption spectrum of modified against virgin inhibitor. The solvent perturbation spectra show an increase of the fraction of exposed tyrosyls from 0.45 in the virgin inhibitor to 0.59 in the modified form. Comparison of the circular dichroism spectra of the modified and virgin inhibitors reveals a decrease of the mean residue ellipticity in the tyrosine and peptide bond region of the modified inhibitor. In the fluorescence spectra a 50% increase in the quantum yield of the tyrosine fluorescence is observed in the modified inhibitor. All these spectroscopic data support the idea, which is also evidenced by the X-ray crystallographic model, that in the modified inhibitor up to five residues from Ala-16 to Arg-20 gain rotational freedom.