Extracorporeal membrane oxygenation and acute kidney injury: a single-center retrospective cohort

To assess the relationship between acute kidney injury (AKI) with outcomes among patients requiring extracorporeal membrane oxygenation (ECMO). This is a single-center, retrospective cohort study of adult patients admitted to intensive care units (ICU) at a tertiary referral hospital requiring ECMO from July 1, 2015, to August 30, 2019. We assessed the temporal relationship of AKI and renal replacement therapy with ECMO type (VV vs. VA). The primary outcome was in-hospital mortality rates. We used Kruskal-Wallis or chi-square tests for pairwise comparisons, cause-specific Cox proportional hazards models were utilized for the association between AKI prevalence and in-hospital mortality, and a time-dependent Cox model was used to describe the association between AKI incidence and mortality. After the screening, 190 patients met eligibility criteria [133 (70%) AKI, 81 (43%) required RRT]. The median age was 61 years, and 61% were males. Among AKI patients, 48 (36%) and 85 (64%) patients developed AKI before and after ECMO, respectively. The SOFA Day 1, baseline creatinine, respiratory rate (RR), use of vasopressin, vancomycin, proton pump inhibitor, antibiotics, duration of mechanical ventilation and ECMO, and ICU length of stay were higher in AKI patients compared with those without AKI (P < 0.01). While ICU and in-hospital mortality rates were 46% and 50%, respectively, there were no differences based on the AKI status. The type and characteristics of ECMO support were not associated with AKI risk. Among AKI patients, 77 (58%) were oliguric, and 46 (60%) of them received diuretics. Urine output in the diuretic group was only higher on the first day than in those who did not receive diuretics (P = 0.03). Among ECMO patients, AKI was not associated with increased mortality but was associated with prolonged duration of mechanical ventilation and ICU length of stay.

Machine learning in data abstraction: A computable phenotype for sepsis and septic shock diagnosis in the intensive care unit

BACKGROUND

With the recent change in the definition (Sepsis-3 Definition) of sepsis and septic shock, an electronic search algorithm was required to identify the cases for data automation. This supervised machine learning method would help screen a large amount of electronic medical records (EMR) for efficient research purposes.

AIM

To develop and validate a computable phenotype via supervised machine learning method for retrospectively identifying sepsis and septic shock in critical care patients.

METHODS

A supervised machine learning method was developed based on culture orders, Sequential Organ Failure Assessment (SOFA) scores, serum lactate levels and vasopressor use in the intensive care units (ICUs). The computable phenotype was derived from a retrospective analysis of a random cohort of 100 patients admitted to the medical ICU. This was then validated in an independent cohort of 100 patients. We compared the results from computable phenotype to a gold standard by manual review of EMR by 2 blinded reviewers. Disagreement was resolved by a critical care clinician. A SOFA score ≥ 2 during the ICU stay with a culture 72 h before or after the time of admission was identified. Sepsis versions as V1 was defined as blood cultures with SOFA ≥ 2 and Sepsis V2 was defined as any culture with SOFA score ≥ 2. A serum lactate level ≥ 2 mmol/L from 24 h before admission till their stay in the ICU and vasopressor use with Sepsis-1 and-2 were identified as Septic Shock-V1 and-V2 respectively.

RESULTS

In the derivation subset of 100 random patients, the final machine learning strategy achieved a sensitivity-specificity of 100% and 84% for Sepsis-1, 100% and 95% for Sepsis-2, 78% and 80% for Septic Shock-1, and 80% and 90% for Septic Shock-2. An overall percent of agreement between two blinded reviewers had a k = 0.86 and 0.90 for Sepsis 2 and Septic shock 2 respectively. In validation of the algorithm through a separate 100 random patient subset, the reported sensitivity and specificity for all 4 diagnoses were 100%-100% each.

CONCLUSION

Supervised machine learning for identification of sepsis and septic shock is reliable and an efficient alternative to manual chart review.

Structural analysis of FeO(1 1 1)/Ag(0 0 1): undulation of hexagonal oxide monolayers due to square lattice metal substrates

Iron oxide monolayers are grown on Ag(0 0 1) via reactive molecular beam epitaxy (metal deposition in oxygen atmosphere). The monolayer shows FeO stoichiometry as concluded from x-ray photoemission spectra. Both low energy electron diffraction as well as scanning tunneling microscopy demonstrate that the FeO layer has a quasi-hexagonal (1 1 1) structure although deposited on a surface with square symmetry. Compared to bulk values, the FeO(1 1 1) monolayer is unidirectionally expanded by 3.4% in [Formula: see text] directions while bulk values are maintained in [Formula: see text] directions. In [Formula: see text] directions, this lattice mismatch between FeO(1 1 1) monolayer and Ag(0 0 1) causes a commensurate undulation of the FeO monolayer where 18 atomic rows of the FeO(1 1 1) monolayer match 17 atomic rows of the Ag(0 0 1) substrate. In [Formula: see text] directions, however, the FeO(1 1 1) monolayer has an incommensurate structure.

'We've been through it all together': supports for parents with children with rare trisomy conditions

BACKGROUND

Parenting a child with a developmental disability can be a positive experience. A salient part of this outcome is support at the time of diagnosis and in an ongoing manner from immediate and extended family members. Studies are sparse on this topic for parents with a child with a rare trisomy condition.

METHOD

The present study examined the support needs of parents with a child or adult with a rare trisomy condition (n = 20). Participants were recruited from the Tracking Rare Incidence Syndromes (TRIS) project. The TRIS Family, Friends and Finances Protocol was the data collection instrument. The protocol included primarily open-ended items. Qualitative analyses were conducted to identify themes from the protocol and follow-up phone contacts.

RESULTS

Support from immediate and extended family members varied from very positive to participants-describing very negative interactions with specific individuals. Many in the sample reported affirming experiences with spouses and difficulties with grandparents and other extended family members.

CONCLUSIONS

Results both confirmed the literature and reflected the unique circumstances of the participants. It is critical to raise awareness of the similar and disparate support needs of this unique population, as the affected children are living longer and their families require continuing support to meet their and their children's needs.

Post-deposition annealing of praseodymia films on Si(111) at low temperatures

Thin heteroepitaxial praseodymia films with fluorite structure on Si(111) were annealed under ultra-high vacuum conditions at temperatures in the region of 100 up to 300 °C. Afterward investigations by x-ray diffraction, grazing incidence x-ray diffraction and x-ray reflectometry were performed to obtain information about structural changes of the film during the annealing process. For this reason, praseodymia Bragg peaks were carefully analyzed within the kinematic diffraction theory. This analysis demonstrates the coexistence of different praseodymia phases depending on the conditions of preparation. Here, annealing of the samples up to 150 °C leads to a homogeneous film with a PrO(1.833) phase and with negligible strain since both the lateral and vertical lattice parameters nearly match the corresponding bulk praseodymia phase. Further annealing leads to oxygen loss accompanied by significantly increased lattice parameters. Since the lateral lattice parameter is pinned at the interface, the vertical lattice constant has to increase considerably due to the tetragonal distortion of the film. This causes the decomposition of the film into two oxide species with significantly different oxygen contents. Annealing at 300 °C reduces the film almost completely to PrO(1.5) which has the minimum content of oxygen.

Evidence for Jahn-Teller distortions at the antiferromagnetic transition in LaTiO3

LaTiO3 is known as a Mott insulator which orders antiferromagnetically at T(N)=146 K. We report on results of thermal expansion and temperature dependent x-ray diffraction together with measurements of the heat capacity, electrical transport measurements, and optical spectroscopy in untwinned single crystals. At T(N) significant structural changes appear, which are volume conserving. Concomitant anomalies are also observed in the dc resistivity, in bulk modulus, and optical reflectivity spectra. We interpret these experimental observations as evidence of orbital order.

Hemoconcentration: an early marker of severe and/or necrotizing pancreatitis? A critical appraisal

OBJECTIVE

A study was designed to reevaluate hemoconcentration as an early marker of severe and/or necrotizing pancreatitis and compare it against contrast-enhanced CT, the gold standard to diagnose acute necrotizing pancreatitis.

METHODS

This prospective study covers the years 1988-1999 for 316 patients (202 male, 114 female) with a first attack of acute pancreatitis. The role of the hematocrit as an early marker of severe and/or necrotizing pancreatitis has been retrospectively evaluated against the prospectively obtained data. They all underwent a CT within 72 h after admission. In addition to the CT-controlled diagnosis of interstitial/necrotizing pancreatitis, the following variables were used to assess severity: initial organ failure according to the Atlanta classification; indication for artificial ventilation and/or dialysis; Ranson score adjusted for etiology; Imrie score; Balthazar score; length of stay in intensive care unit (ICU); total hospital stay; development of pancreatic pseudocysts; indication for operation (necrosectomy); and mortality. Hemoconcentration on admission was defined as a hematocrit level >43.0% for male and >39.6% for female patients. Logistic regression was used to assess the correlation between hemoconcentration and the severity of variables.

RESULTS

Hematocrit, as a single parameter measured on admission, had the same sensitivity and negative predictive value as the more complicated Ranson and Imrie scores obtained only after 48 h. However, its specificity, positive predictive value, and total accuracy were lower. Hemoconcentration significantly correlated with the Balthazar score (differential diagnosis between interstitial and necrotizing pancreatitis), stay in ICU, and total hospital stay. Sensitivity and specificity of the hematocrit cut-off level of 43.0% for male and 39.6% for female patients to detect necrotizing pancreatitis were 74% and 45%, respectively. The positive predictive value was 24% and the negative predictive value 88%. Receiver operation characteristics (ROC) curve values for several cut-offs did not result in more ideal levels.

CONCLUSION

Hemoconcentration does not significantly correlate with important clinical outcome variables of acute pancreatitis including organ failure and mortality rate. Its prognostic value is comparable to the more complicated Ranson and Imrie scores obtained only after 48 h. The major value of this single easily obtainable and cheap parameter on admission lies in its high negative predictive value. In the absence of hemoconcentration, contrast-enhanced CT may be unnecessary on admission unless the patient does not improve.

Quantal release of serotonin

We have studied the origin of quantal variability for small synaptic vesicles (SSVs) and large dense-cored vesicles (LDCVs). As a model, we used serotonergic Retzius neurons of leech that allow for combined amperometrical and morphological analyses of quantal transmitter release. We find that the transmitter amount released by a SSV varies proportionally to the volume of the vesicle, suggesting that serotonin is stored at a constant intravesicular concentration and is completely discharged during exocytosis. Transmitter discharge from LDCVs shows a higher degree of variability than is expected from their size distribution, and bulk release from LDCVs is slower than release from SSVs. On average, differences in the transmitter amount released from SSVs and LDCVs are proportional to the size differences of the organelles, suggesting that transmitter is stored at similar concentrations in SSVs and LDCVs.

Hostility and Violent Ideation: Physical Rehabilitation Patient and Community Samples

OBJECTIVES

To assess the relative frequency of violent ideation [VI] in physical rehabilitation and community samples, and to identify associated factors.

DESIGN

Analysis of variables from the Battery for Heath Improvement using MANOVA, ANOVA and chi(2) analyses.

SETTING

Medical sites in 30 US states, and community sites in 16 US states, overall representing 36 US states.

PARTICIPANTS

527 physical rehabilitation patients suffering from both acute and chronic pain conditions, and 725 community members. Subjects from both groups were drawn from a larger pool of 2,262 subjects.

INTERVENTIONS

None.

OUTCOME MEASURES

The Hostility scale and a VI critical item from the Battery for Heath Improvement (BHI).

RESULTS

The patient group reported significantly more violent ideation than did the community group. VI was also significantly associated with involvement in workers' compensation or personal injury insurance systems, work conditioning programs, the BHI Hostility scale, and a number of other psychosocial factors.

CONCLUSIONS

Recent research supports the contention that there is a relationship between ideation, angry affect, aggressive behavior and delayed recovery. Thus the presence of VI in the patient should be a cause for concern, and has clear ramifications for those working in the clinical setting. Primary prevention should involve not only the identification of hostile patients at risk for VI and aggression, it should also involve identifying programs or systems where a higher incidence of VI is likely to be observed. As VI was found to be associated with a range of variables, including characterological disorders, mood and social conflict, a further evaluation of factors contributing to VI would be recommended prior to intervention.

Parathyroid hormone-related protein mRNA in sheep endometrium and myometrium during late gestation and labor

OBJECTIVE

To determine quantitative changes of parathyroid hormone-related protein (PTHrP) mRNA in sheep myometrium and endometrium during late gestation and labor.

METHODS

Tissues were obtained from 22 pregnant ewes under halothane anesthesia: early controls at 131 days' gestational age (dGA) not in labor (ECNL; n = 6); during cortisol-induced premature labor (CPL at 131 dGA; n = 6); in term spontaneous labor (STL at 140-145 dGA; n = 5); or term control animals not in labor (TCNL at 140-145 dGA; n = 5). Total RNA was extracted and subjected to Northern blot analysis. Blots were probed with a human PTHrP cDNA probe, stripped, and rehybridized with an 18s rRNA nucleotide probe to normalize PTHrP mRNA levels.

RESULTS

Endometrial PTHrP mRNA:18s was unaffected by gestational age or labor in tissues from the four groups. In contrast, myometrial PTHrP mRNA:18s ratio was decreased when TCNL and STL were compared with both ECNL and CPL groups (P < .05).

CONCLUSIONS

Significant changes occur at the end of gestation in pregnant ovine myometrium PTHrP mRNA but not in the endometrium. In myometrium PTHrP mRNA levels were down-regulated at term regardless of whether labor was present. It seems that PTHrP mRNA levels in myometrium are related to gestational age rather than to labor per se in sheep. We hypothesize that PTHrP may play a role in maintaining uterine quiescence until term, at which time levels fall allowing myometrial contractile activity to increase unopposed by PTHrP.

Changes in human motor cortex excitability induced by dopaminergic and anti-dopaminergic drugs

Transcranial magnetic stimulation was used to probe the acute effect of a single oral dose of various dopaminergic (levodopa, selegiline, bromocriptine) and antidopaminergic drugs (sulpiride, haloperidol) on motor cortex excitability in healthy volunteers. Motor threshold, intracortical inhibition and intracortical facilitation were tested in the abductor digiti minimi muscle. The latter two parameters were studied in a conditioning-test paired stimulus paradigm. The principal findings were an increase in intracortical inhibition by bromocriptine, and, conversely, a decrease in intracortical inhibition and an increase in intracortical facilitation by haloperidol. Effects peaked at delays consistent with the pharmacokinetics of the two drugs and were fully reversible. In conclusion, dopamine receptor agonists and antagonists can be considered inverse modulators of motor cortex excitability: the former enhance inhibition while the latter reduce it. The relation of the present findings to current models of motor excitability abnormalities in movement disorders will be discussed.

Inhibition of transmitter release correlates with the proteolytic activity of tetanus toxin and botulinus toxin A in individual cultured synapses of Hirudo medicinalis

We have studied the effects of tetanus toxin and botulinus toxin A on neurotransmitter release in the Retzius-->P-cell synapse of the leech and exploited the unique properties of this system, which allow for combined physiological and biochemical analyses in single-cell pairs. The sequences of Hirudo medicinalis synaptobrevin and synaptosomal-associated protein of 25 kDa (SNAP-25), deduced by cDNA cloning, are 61 and 55% identical, respectively, to their corresponding mammalian homologs. Whereas Hirudo synaptobrevin is proteolyzed by tetanus toxin, its SNAP-25 isoform is resistant to botulinus toxin A cleavage because of amino acid substitutions within and around the putative cleavage site. In close correlation, microinjection of tetanus toxin into the presynaptic neuron produced a block of transmitter release, whereas botulinus toxin A had no effect on synaptic transmission. Subsequent immunoblotting of single-cell pairs demonstrated directly that the tetanus toxin-mediated block of exocytosis is accompanied by cleavage of synaptobrevin in the injected neuron, resulting in the generation of a detectable C-terminal cleavage product. Immunoblotting also confirmed the resistance of SNAP-25 to botulinus toxin A cleavage in vivo. Using recombinant proteins, we show that the N-terminal fragment of synaptobrevin released by tetanus toxin, but not its C-terminal membrane-anchored cleavage product, participates with syntaxin and SNAP-25 in synaptic SNAP receptor (SNARE) ternary complex formation in Hirudo. Our data demonstrate a direct correlation between the inhibition of transmitter release and the ability of the neurotoxin to proteolyze its target protein and support the view that SNARE ternary complex formation is an important step leading to synaptic vesicle exocytosis.

A structural change occurs upon binding of syntaxin to SNAP-25

The highly conserved proteins syntaxin and SNAP-25 are part of a protein complex that is thought to play a key role in exocytosis of synaptic vesicles. Previous work demonstrated that syntaxin and SNAP-25 bind to each other with high affinity and that their binding regions are predicted to form coiled coils. Circular dichroism spectroscopy was used here to study the alpha-helicity of the individual proteins and to gain insight into structural changes associated with complex formation. Syntaxin displayed approximately 43% alpha-helical content. In contrast, the alpha-helical content of SNAP-25 was low under physiological conditions. Formation of the SNAP-25-syntaxin complex was associated with a dramatic increase in alpha-helicity. Interaction of a 90-residue NH2-terminal fragment of SNAP-25 comprising the minimal syntaxin binding domain lead to a similar but less pronounced increase in alpha-helicity. Single amino acid replacements in the putative hydrophobic core of this fragment with hydrophilic amino acids abolished the induced structural change and disrupted the interaction monitored by binding assays. Replacements with hydrophobic residues had no effect. Our findings are consistent with induced coiled coil formation upon binding of syntaxin and SNAP-25.

Enhancement of human motor cortex inhibition by the dopamine receptor agonist pergolide: evidence from transcranial magnetic stimulation

Focal transcranial magnetic stimulation was used to evaluate the effect a single oral dose (0.125 mg) of the dopamine agonist pergolide on the excitability of the motor cortex in five healthy subjects. Resting and active motor thresholds of the abductor digiti minimi muscle were unaffected. The mean duration of the cortical silent period was significantly lengthened by up to 22 ms. The cortico-cortical inhibition as studied by a paired conditioning-test stimulation (interstimulus intervals of 1-5 ms) was enhanced significantly while the cortico-cortical facilitation at longer intervals (6-15 ms) showed only an insignificant trend towards less facilitation. All effects peaked at 3 h after drug intake and were reversible after 24 h. Peripheral motor excitability as tested by the duration of the peripheral silent period and the size of the maximum M wave remained unchanged. The present data support the view that pergolide is capable of enhancing motor cortex inhibition which is known to be deficient in idiopathic Parkinson's disease.

Real-time measurement of transmitter release from single synaptic vesicles

Neurotransmitter release is mediated by Ca2+ dependent exocytosis of synaptic vesicles. Neither the amount of transmitter released from individual synaptic vesicles nor the kinetics of this process have yet been directly determined. Using carbon fibres as electrochemical detectors, we have measured release of the neurotransmitter serotonin from cultured neurons of the leech. This technique allowed us to monitor transmitter discharge from single synaptic vesicles as spike-like oxidation currents at high time resolution, providing new insight into the mechanism of neuronal exocytosis. Two types of signals were characterized, corresponding to exocytosis of small clear and large dense core vesicles present in these cells. A small vesicle discharges about 4,700 transmitter molecules with a time constant in the region of 260 microseconds, whereas large vesicles release their content of approximately 80,000 molecules with a time constant of about 1.3 ms. Release from both vesicle types is initiated rapidly, with a rise time of less than 60 microseconds, suggesting an abrupt opening of a preassembled fusion pore.

A fast activating presynaptic reuptake current during serotonergic transmission in identified neurons of Hirudo

An electrogenic serotonin (5-HT) uptake process was characterized in the serotonergic Retzius-P cell synapse of the leech, and the simultaneous activation of this presynaptic reuptake and the postsynaptic response was monitored during evoked transmitter release. A presynaptic, Na(+)-dependent inward current upon application of 5-HT was isolated at membrane potentials between -80 and +60 mV. Its identification as a transmitter uptake current was confirmed by monitoring accumulation of the autofluorescent 5-HT analog 5,7-dihydroxytryptamine during activation of this current. To study the kinetics of 5-HT reuptake in functional synapses, transmitter release was stimulated by flash photolysis of the Ca(2+)-caging DM-nitrophen. The results demonstrate that reuptake activates with a minimal delay of less than a millisecond during synaptic transmission. It acts as a rapid transmitter removal system to determine the time course of the postsynaptic response and monitors the kinetics of transmitter clearance at the synaptic site.

Isolation of a plant glycoprotein involved with control of intercellular recognition

A recognition molecule was isolated from stigmas of S-allele genotype S(2)S(2) of Brassica oleracea var. capitata L. After Sephadex chromatography, it eluted as a single symmetrical peak during diethylaminoethane-cellulose chromatography. A high degree of purity was affirmed by: sedimentation as a single peak during ultracentrifugation through 5 to 20% sucrose gradients; elution as a single peak from Sephadex G-100; visualization as a single band which stains with Coomassie blue and periodic acid Schiff reagent after electrophoresis on polyacrylamide gels. Other criteria supporting the conclusion that it is a glycoprotein are: (a) the highly purified preparation is anthrone-positive and has a Lowry protein to anthrone-positive carbohydrate ratio of 1.3; (b) the preparation contains arabinose, galactose, glucose, and mannose, although it is not precipitated by concanavalin A; (c) the immunological properties of the molecule are lost following protease treatment, and it has a molecular weight of 90,000 by Sephadex gel-filtration analysis and 54,500 by velocity sedimentation analysis.In vitro pretreatment of S(2)S(2) pollen with the post-diethylaminoethane-purified S(2) glycoprotein prevented the S(2)S(2) pollen from germinating on three classes of compatible stigmas: (a) mature stigmas of genotypes S(3)S(3) and S(8)S(8), which are non-self genotypes; (b) immature stigmas of genotype S(2)S(2), where incompatibility is not expressed; and (c) mature stigmas with a recessive S(2) allele. Pretreatment of S(3)S(3) and S(8)S(8) pollen with the S(2) glycoprotein did not interfere with their germination.

Performance assessment of the GammafloTM automated radioimmunoassay system by assaying for digoxin

We report an evaluation of the GammafloTM automated continuous-flow radioimmunoassay instrument in which we used a digoxin assay to assess system performance. System operation was based on combined continuous-flow and column-chromatographic techniques. No drift or carryover was detectable in 180 within-assay consecutive determinations performed at a rate of 42 determinations per hour (5 h of continuous operation). Within-assay and between-assay precision were less than 6% (coefficient of variation). The automated method correlated well (r = 0.960 and 0.952, respectively) with two established manual digoxin radioimmunoassay procedures. The data suggest this automated system offers a valid alternative to manual radioimmunoassay procedures in terms of overall precision, simplicity of operation, and sample throughout capacity.

Performance assessment of the GammafloTM automated radioimmunoassay system by assaying for digoxin

We report an evaluation of the GammafloTM automated continuous-flow radioimmunoassay instrument in which we used a digoxin assay to assess system performance. System operation was based on combined continuous-flow and column-chromatographic techniques. No drift or carryover was detectable in 180 within-assay consecutive determinations performed at a rate of 42 determinations per hour (5 h of continuous operation). Within-assay and between-assay precision were less than 6% (coefficient of variation). The automated method correlated well (r = 0.960 and 0.952, respectively) with two established manual digoxin radioimmunoassay procedures. The data suggest this automated system offers a valid alternative to manual radioimmunoassay procedures in terms of overall precision, simplicity of operation, and sample throughout capacity.

Endoscopic electrosurgical polypectomies of the upper gastrointestinal tract

The electrosurgical removal of polypoid lesions from the upper gastrointestinal tract with the esophagogastro-duodenoscope has proven to be a safe, effective, and relatively inexpensive procedure. Twenty-six polypectomies performed on 24 different patients are presented. Polyps were removed from the distal esophagus, stomach, duodenum, and jejunum. There were no significant complications.

Potassium load in CPD-preserved whole blood and two types of packed red blood cells

The potassium load of transfused blood must be minimized. We have compared the total plasma potassium content of units of CPD-preserved stored whole blood (SWB), stored packed cells (SPC), and packed cells prepared from stored whole blood (WB-PC). Plasma potassium concentrations, unit weights, and hematocrits of 20 units of SWB, 27 units of SPC, and 20 units of WB-PC of various ages were measured. During the 21-day storage period, total plasma potassium content per unit increased in units of SPC at the same rate as in units of SWB, because plasma potassium concentration increased in SPC at three times the rate of SWB. The values for total plasma potassium per unit at 14 and 21 days in mEq/unit were: SWB, 4.4, 5.8; SPC 3.1, 4.4; and WB-PC 1.9, 2.5. Thus, SPC units may contain substantial amounts of plasma potassium when stored for two to three weeks. However, removal of most of the remaining supernatant plasma from SPC units just prior to administration provides a readily available supply of low potassium blood while allowing maximum conservation of scarce blood resources.