bluuebunny/crossref_metadata_2025 huggingface dataset:
Bovine Platelet Proteins
Authors: Łopaciuk S , Solum N. O
Published: June 2018

1. The protein composition of bovine platelet extracts has been investigated by immunoelectrophoresis and polyacrylamide disc electrophoresis. The information obtained is discussed as a basis for study on platelet fibrinogen.

2. With antiserum to platelet proteins 11 precipitin lines were observed 3 of which corresponded electrophoretically to plasma albumin, fibrinogen and γ-globulin. These lines were not seen using the same antiserum absorbed with bovine plasma. The 8 additional lines were still present indicating that they represented specific platelet components. Antiserum to plasma produced the 3 above-mentioned lines, but no others.

3. With antiserum to purified bovine plasma fibrinogen 3 precipitin lines were observed. The fibrinogen line was the dominant one. The 2 additional lines did not disappear by absorption of the antiserum with bovine serum nor by incubation of the extracts with thrombin. The latter treatment totally removed the fibrinogen line.

4. A non-fibrinogen precipitin line, observed only with the antiserum to platelet extract and positioned in the β2-globulin region, disappeared by the incubation of platelet extracts with thrombin.
Bovine Platelet Proteins II. Purification of Platelet Fibrinogen
Authors: Solum N. O , Łopaciuk S
Published: June 2018

1. Platelet fibrinogen has been purified from washed bovine platelets. The procedure was based on the methods for purification of plasma fibrinogen by fractionated precipitations and extractions with ethanol and glycine below 0°, and precipitation of proteins by dimethylformamide at 0°.

2. The platelet extract obtained by freezing and thawing of the cells, freed from insoluble material by centrifugation at 23,000 x g for 30 min, contained 0.22 ±0.003mg fibrinogen per 109 platelets. Total protein of this fraction was 0.77 ±0.08 mg per 109 platelets whereas that of the insoluble fraction was 0.79 ±0.09 mg per 109 platelets.

3. The most purified platelet fibrinogen fraction contained 91-98% of the protein in a thrombin-clottable state. The yield was approx. 20%. It showed homogeneity in analytical ultracentrifugation, in immunoelectrophoresis using an antiserum produced by immunization of rabbits against platelet extract, and in starch gel electrophoresis using a discontinuous system of Tris HCl and borate buffers offering a high resolution power towards the platelet proteins. Polyacrylamide disc electrophoresis revealed two to three faint lines behind the main fibrinogen line. At least one such line was also observed with purified plasma fibrinogen.
Bovine Platelet Proteins III. Some Properties of Platelet Fibrinogen
Authors: Solum N. O , Łopaciuk S
Published: June 2018

1. Some properties of purified bovine platelet fibrinogen have been described and the data compared to those obtained by parallel analysis of purified bovine plasma fibrinogen.

2. A close similarity was found between platelet and plasma fibrinogen as to sedimentation coefficients, electrophoretic mobilities in starch gel and polyacrylamide disc electrophoresis, light absorption spectra in the range 240 mμ to 330 mμ, ability to form immunoprecipitate with a rabbit antiserum against bovine plasma fibrinogen, total amino acid composition and in N-terminal amino acids.

Differences between the fibrinogens were found as to intrinsic viscosity, carbohydrate content and behaviour upon clotting by thrombin. Intrinsic viscosity in 0.3 M NaCl at 25° was 0.48 dl/g for platelet fibrinogen as compared to 0.26 dl/g for plasma fibrinogen. The carbohydrate content of platelet fibrinogen was 0.56 ± 0.10% 1.56±0.10% and 1.37±0.09% for sialic acid (calculated as N-glycolyl neuraminic acid), hexose (galactose/mannose 1:2) and hexosamine (glucosamine), respectively. These values were 6, 54 and 26% higher than those found for plasma fibrinogen. The difference in clotting behaviour indicated a slower polymerization rate of the fibrin monomers formed from platelet fibrinogen than of those formed from plasma fibrinogen.
Decrease of Platelet Aggregating Activity of Soluble Human Collagen Fractions during Ageing
Authors: Bańkowski E , Niewiarowski S , Rogowski W
Published: June 2018

Human collagen fractions of different solubility were prepared from aorta and skin homogenate using a differential centrifugation technique. All fractions of collagen aggregated platelets. The specific platelet aggregating activities were calculated as minimal hydroxyproline concentrations (MHC) causing platelet aggregation. The specific platelet aggregating activity was the highest in the soluble collagen fraction of young human subjects and then it decreased considerably (500 times on the average) during ageing. The specific platelet aggregating activity of young insoluble collagen was lower but it decreased less significantly during ageing. The changes in hexoses and hexosamines content of various collagen fractions did not appear to be relevant as regards platelet aggregating activity. It has been postulated that the masking of free amino groups in aged collagen following cross-links formation may be responsible, at least in part, for the loss of platelet aggregating activity of this protein.
Platelet Surface Charge and Aggregation Effects of Polyelectrolytes
Authors: Gröttum K. A
Published: June 2018

The effect on platelet surface charge by adding the polybases : Dextran-DEAE and Polybrene and the polyacids : Dextran sulphate, heparin and bovine platelet fibrinogen to platelet-rich plasma was studied by platelet electrophoresis. In small concentrations all the reagents decreased the electrophoretic mobility of platelets, but not that of erythrocytes, suggesting that the polymeric agents were specifically adsorbed to the platelets and thereby reducing their negative surface charge. When the reagents reduced the electrophoretic mobility of the platelets to 85% of normal, platelet aggregation was induced. This effect was probably not mediated through release of ADP, as the presence of ADPase did not modify the effect. The influence of polybases was not inhibited by EDTA. The effect of Dextran sulphate was inhibited by EDTA and increased by small amounts of calcium ions. Increasing concentrations of Dextran sulphate and heparin increased the electrophoretic mobility of platelets, but did not aggregate the platelets. The results suggest that a decrease in the platelet electrostatic potential is essential in platelet aggregation.
Platelet Phospholipids and Stypven Clotting Time
Authors: Hovmand L. L , Brøns K , Gormsen J
Published: June 2018

1. Phospholipids in the thrombocytes were studied in 16 healthy individuals, 18 patients with hepatic cirrhosis and 11 patients suffering from a variety of illnesses which are generally considered to be connected with thrombocytopathy.

2. In patients with hepatic cirrhosis the total amount of phospholipids was significantly lower: 8 (µg ± 2 µg lipid P per 109 platelets compared to 12 (µg ± 2 (µg lipid P per 109 platelets in healthy individuals.

3. The percentage composition of the phospholipids was the same for healthy individuals as for the diseased persons.

4. Decrease in platelet factor 3 activity as estimated by a modified stypven clotting time has been demonstrated using the thrombocytes from the patients suffering from hepatic cirrhosis whereas the activity was normal in uremic patients tested. The decreased clotting activity might partly be due to the reduced total amount of phospholipids. Surface active agents exert a much more profound reduction in clotting activity of phospholipids. It is concluded, that surface charge of phosphatide micelles determines their clotting activity more than concentration of all or a single phospholipid.
Hämolytisch-hämorrhagischer Transfusionszwischenfall mit Koagulopathie infolge inkompletter Blutgruppen-Antikörper
Authors: Kluge A , Krah E , Schimpf KL
Published: June 2018

Es wird über einen akuten hämolytisch-hämorrhagischen Transfusionszwischenfall berichtet, der zu einer Koagulopathie führte. Bei den wenigen Berichten über hämorrhagische Transfusionszwischenfälle in der Literatur, bei denen Gerinnungsanalysen vorgelegt wurden, handelte es sich fast ausschließlich um eine intravasale Hämolyse von A- oder B-Erythrozyten durch die unverträglichen regulären (Iso-)Antikörper des Empfängers als Verwechslungsfolge. Bei dem hier geschilderten und gerinnungsanalytisch untersuchten Fall war die postoperative hämolytische Transfusionsreaktion durch irreguläre inkomplette Antikörper verursacht worden und ging mit einer Koagulopathie einher. Diese irregulären inkompletten Antikörper hatten ihrer Natur nach nicht zu einer sofortigen intravasalen Hämolyse, sondern zu einer protrahierten, im retikuloendothelialen System ablaufenden Erythrozytenzerstörung geführt. Die Besonderheit einer Freisetzungsreaktion von gerinnungsaktiven Substanzen durch Immunreaktion und nachfolgende intralienale Erythrozytensequestration wird betont. Es bestand das voll ausgeprägte Krankheitsbild mit lebensbedrohlicher hämorrhagischer Dia these, hochgradiger Blutungsanämie, akutem Mer enver sagen und den charakteristischen Hämolysezeichen, jedoch normalem Komplementgehalt.
A New Type of Coagulation Inhibitor
Authors: Lechner K
Published: June 2018

1. In 2 patients blood coagulation inhibitors have been found. The first patient showed pancytopenia, splenomegaly and increase of macroglobulins in serum, no definite clinical diagnosis could be established. The second patient had a history of thromboembolic diseases, but appeared healthy at the time of investigation.

2. Clotting time, partial thromboplastin time and prothrombin time were prolonged in both patients. All clotting factors were normal if tested in dilution. Plasma and serum of the patients prolonged the partial thromboplastin time and prothrombin time of normal plasma.

3. Using partially purified clotting factors it could be shown that the inhibitors inhibit the activation of prothrombin by prothrombin activator (reaction product of F Xa+ F V+lipid). The velocity of thrombin generation and the amount of thrombin generated was reduced.

4. The inhibitory activity in both cases was present in the macroglobulin peak after gel filtration, slight activity was detected also in the G-peak in case 2. After DEAEchromatography, activity appeared in both cases in those fractions which contain IgM, in case 2 also in the first protein fractions containing only IgG.

5. Inhibitor activity could be reduced in both cases only be incubation with anti-IgM antiserum.

6. It is concluded that the inhibitor in case 1 is IgM and in case 2 IgM-IgG.
Isolierung des Kontaktaktivierungsproduktes des Gerinnungssystems aus Schweineplasma
Authors: Barth P , Kommerell B , Beckmann U
Published: June 2018

Es wird iiber die Isolierung des Kontaktaktivierungsproduktes des Gerinnungssystems berichtet. Die Reinigungsschritte bestanden in Celite-Adsorption, DEAECellulose- Adsorption, DEAE-Sephadex-Adsorption und Elution. Das so gereinigte Material, das außer Kontaktaktivierungsprodukt-Aktivität keine weiteren Gerinnungseigenschaften aufwies - außer einer leichten Faktor-IX-Aktivität, die durch BaSO 4-Adsorption des Ausgangsplasmas vermieden werden konnte - , war einheitlich bei der Gelchromatographie an Sephadex G 200, in der Immunpräzipitation und in der Immunelektrophorese. Die Diskelektrophorese zeigte noch eine sehr schwache zweite

Bande.
Über einen Einstufentest zur Bestimmung des Kontaktaktivierungsproduktes des Gerinnungssystems
Authors: Barth P , Kommerell B , Oswald M
Published: June 2018

Es wird eine einfache Einstufenmethode zur Bestimmung des KAP des Gerinnungssystems mitgeteilt. Als Mangelplasma dient ein Humanplasma, das 6mal mit Celite behandelt wurde unter Zusatz von 30% Michaelis-Puffer, pH 7,6. Die Celite-Adsorption erfolgte bei +4° C. Auf diese Weise wird bei vollständiger Elimination des Kontaktaktivierungsproduktes eine weitgehende Erhaltung der übrigen Gerinnungsfaktoren erreicht. Einzelheiten der spezifischen Empfindlichkeit des Testsystems werden diskutiert.
The Flowing Clotting Time (Thrombus Formation Time) a Sensitive Test of Hypercoagulability
Authors: Engelberg H , Engelberg L. P
Published: June 2018

The addition of small amounts of extrinsic thromboplastin or of thrombin to blood in vitro accelerated coagulation more frequently and to a greater extent when determined by the flowing time test than when measured by the silicone clotting time, or by the blood or plasma heparin tolerance tests. Similar results were obtained when intrinsic thromboplastin formation was stimulated by contact with glass. However there was little or no acceleration of the flowing clotting time of plasma obtained from aliquots of the thromboplastin-containing blood. These results indicate that the flowing clotting time (thrombus formation time) of whole blcod is a more reliable test of hypercoagulability than previously described blood or plasma clotting time tests.
The Influence of the Polysaccharide Carrageenin on the Clotting Mechanism of the Blood in the Rabbit in Vitro and in Vivo
Authors: Schimpf K L , Lenhard J , Schaaf G
Published: June 2018

Carrageenin is not an antithrombin. It inhibits fibrin aggregation or polymerisation. The inactivation of thrombin by antithrombin and of blood thromboplastin by anti blood thromboplastin is neither accelerated nor retarded. In the presence of Carrageenin the clotting times of tests in which the fibrinpolymerisation phase is involved are lengthened; this simulates a decrease in clotting factors. In vivo Carrageenin, despite its coagulation-inhibitory properties, is not able to reverse the consumption reaction which it has initiated.
Recent Investigations on the Chemical Nature of Thromboplastin (“TP”) from Human Brain
Authors: Hecht E , Wijngaards G
Published: June 2018

It was confirmed that purified thromboplastin from human brain tissue contains about 18 amino acids after hydrolysis.

The following observations gave rise to a discussion if these amino acids are to be considered as contaminations only, or if they derived from a protein moiety of brain thromboplastin.

The amino acids are present in all fractions of the thromboplastin and in the wash solutions, and their amount is very small.

The amino acids cannot be removed from thromboplastin with the usual techniques, but amino acids and peptides added on purpose can be separated again.

Investigations with DNFB pointed to the presence of a great number of precipitable small peptides of various composition. The possibility of the presence of a microamount of a long-chain peptide, or even a trace of protein could not be excluded.

Four techniques to separate the amino acid-rich fraction of thromboplastin were studied, described, and the results obtained compared. Sephadex G-25 was most successful, and the fractions were analysed.

Most striking was the percentage of aspartic acid in the non-lipid fraction, which is 13-26 times lower than that of proteins and lipoproteins.

The biological investigations of these fractions are subject of the subsequent paper.
On the Functional Resynthesis of Thromboplastin (“TP”) from its Fractions and Various Substitutes
Authors: Hecht E , Wijngaabjds G
Published: June 2018

Recombination of the low active lipid fraction with the inactive non-lipid fraction of brain thromboplastin has been proved to be just as successful in restoring the original high thromboplastic activity as the recombination of the corresponding material obtained from lung thromboplastin.

The properties of the individual components, of thromboplastin, its fractions obtained by different ways, and of their substitutes were studied comparatively; the influence of the solvents used was also investigated.

Experiences obtained were collected to prepare a high active and stable brain thromboplastin.

Only the lipid- and non-lipid fraction obtained by pyridin is successful in regenerating the original thromboplastic activity, in contrast with the reunion of both fractions produced by Sephadex G-25, Sephadex LH-20 and butanol.

The lipid fraction can be fully replaced by the lipid activator, PE from soy-beans and partly by synthetic dioleoyl PE, however this is not possible with natural and synthetic PC and lyso PC.

The results of experiments to replace the non-lipid fraction by various amino acids, peptides or proteins were poor.

A full regeneration of the thromboplastic activity with the suspended fractions is only successful after a previous solution of the components in pyridin or chloroform and evaporation.

The rebuilt of the original thromboplastic activity was complete only as long as contaminated non-lipid fractions were used. Non-lipid fractions, quantitatively free of lipids, were ineffective.
Erfahrungen und Modifikationen zur Herstellung von Prothrombin nach Seegers
Authors: Andrassy K , Krause W , Egbring R , Egli H
Published: June 2018

In der vorliegenden Arbeit wird über Erfahrungen bei der Herstellung von Prothrombin nach Seegers berichtet, die zu einigen Modifikationen Veranlassung gaben. Die Präparate weisen entsprechend den Seegersschen Forderungen hohe Aktivitäten pro mg Tyrosin auf. Die durchschnittliche Prothrombinaktivität von 30 Präparaten lag bei 30786 E/mg Tyrosin.
The Reaction of Thiol Compounds with the Vitamin-K Dependent Clotting Factors
Authors: Fantl P
Published: June 2018

Treatment of human and dog oxalated plasma with 0.2 to 1.0 × 10−1 M 2.3-dithiopropanol (BAL) or dithiothreitol (DTT) at 2–4° C for 30 min results in the reduction of the vitamin-K dependent clotting factors II, VII, IX and X to the respective-SH derivatives. The reaction is pH dependent. Under aerobic conditions the delayed one stage prothrombin time can be partly reversed. Under anaerobic conditions a gradual prolongation of the one stage prothrombin time occurs without reversal.

In very diluted plasma treated with the dithiols, prothrombin can be converted into thrombin if serum as source of active factors VII and X is added. In contrast SH factors VII, IX and X are inactive in the specific tests. Reoxidation to active factors II, VII, IX and X takes place during adsorption and elution of the SH derivatives. The experiments have indicated that not only factor II but also factors VII, IX and X have active-S-S-centres.
Reaction Kinetics of Thrombin Activity in Decalcified Plasma and Blood
Authors: Pálos L. A , Sas G , Csurgay A
Published: June 2018

The reaction kinetics of the second phase of blood clotting (conversion of fibrinogen to fibrin) has been studied in euglobulin and thrombin-antithrombin systems. It was intended to set up relationships that would make mathematical expression of the processes possible and which would, moreover, help in detecting dynamic and functional relationships characteristic of the mechanism involved in coagulation.

The experiments have yielded the following results:

1. In the euglobulin solution containing no antithrombin the fibrinogen-thrombin reaction can be characterized with a constant deviation from the first order kinetics.

2. The process of thrombin inactivation is a reaction of first order in the initial phase.

3. The two basic processes (clotting by thrombin in euglobulin solution, inactivation of thrombin in defibrinated plasma) make it possible to predetermine the thrombin time of citrated plasma. Theoretical and actual clotting times were in good agreement.

4. The thrombin time of plasma can be computed even if thrombin is not introduced to the system at one stride but gradually, a manner of administration which is a better imitation of what happening in vivo.

5. In connection with the computation of the “thrombin time” of citrated blood, we determined experimentally (and expressed by means of a function) the modification produced by the corpuscular elements of the blood in the reaction between fibrinogen and thrombin under atraumatic conditions.
Comparative Study of Proactivators of the Fibrinolysin System in Three Mammalian Species
Authors: Takada Y , Takada A , Ambrus J. L
Published: June 2018

Sephadex gel filtration of human plasma gave results suggesting the presence of two proactivators of plasminogen, termed proactivators A and B.

Activity resembling that of proactivator A was found in rabbit plasma, but not in guinea pig plasma.

Plasminogen activators produced by the interaction of proactivator A of human plasma with streptokinase had no caseinolytic or TAMe esterolytic effect.

Proactivator A can be separated in a form apparently free from plasminogen, as shown by the heated fibrin plate test and by immunological analysis. On the other hand, proactivator B concentrates prepared so far are contamined with plasminogen.

Human proactivators appear to be far more susceptible to streptokinase than are rabbit proactivators.

Inhibitors of the fibrinolysin system were observed in the plasmas of all 3 species. These inhibitors are not present in the euglobulin fraction of plasma. Sephadex fractionation of euglobulin fractions results in proactivator preparations that do not contain inhibitors.
Thromboplastin as a Clotting Factor
Authors: Quick A. J
Published: June 2018

The clotting activity of platelets can be sensitively measured by the prothrombin consumption time using normal platelet-depleted plasma as the assay medium. Such plasma when clotted in a glass tube shows no demonstrable consumption of prothrombin but as platelets are added in increasing amounts, the utilization of prothrombin is increased in an approximately straight-line proportion. Similar results are obtained when certain agents such as the Bell-Alton reagent, Inosithin and hemolysate, all of which have a high concentration of phospholipids and are employed in the thromboplastin generation test as platelet substitutes, were assayed by the prothrombin consumption test. Both Inosithin and the Bell-Alton reagent fail to cause significant consumption of prothrombin when the plasma is clotted in silicone-coated tubes, thereby demonstrating the need of a contact factor which is probably thrombin. Since Inosithin which is of plant origin functions efficiently as a platelet substitute in the thromboplastin generation test and in the prothrombin consumption assay test, it presents the probability that the clotting factor in platelets could be of exogenous origin. Its release from platelets requires the action of thrombin.
Current Blood Clotting Schemes
Authors: Quick A. J ,   Professor Emeritus of Biochemistry
Published: June 2018

Currently, there are three schemes to explain the coagulation of blood, each representing an attempt to unravel the complex process. The lack of agreement can be attributed, first, to the experimental approaches and, secondly, to the objective. To evaluate accurately the reliability of the various methods employed in isolating clotting factors and in studying their properties would require the wisdom of Solomon. While both the cascade sequence theory and Seegers’ approach have as their main aim to study the chemistry of blood coagulation, the primary objective of the expanded classical theory is to serve diagnostically. The final goal - the correlation of blood coagulation and hemostasis - can only come clinically. The more clearly the chemistry of the coagulation mechanism is understood and the more accurate the diagnosis, the better will be the prospect of approaching successfully the problem of hemostasis.
Osteogenesis Imperfecta and Extra-/Intradural Hematomas: A Case Report and Review of the Literature
Authors: Celtikci Emrah , Ozgural Onur , Eroglu Umit , Caglar Yusuf , Yakar Fatih
Published: June 2018

Osteogenesis imperfecta, also named as brittle bone disease, is characterized by fragile bones and short stature caused by mutations in the collagen gene. Subdural and intraparenchymal hematomas are defined and associated with trauma, vascular causes, and systemic bleeding diathesis. Skull fragility may lead to epidural hematoma, which is a life-threatening situation. Vascular fragility and intrinsic platelet defects are the causes of bleeding in patients with osteogenesis imperfecta, which is a major management challenge for neurosurgeons. Here, we reported on a 5-year-old boy with osteogenesis imperfecta with epidural hematoma and skull fracture following a trivial trauma, and made a literature review of 28 cases with extra-/intradural hematoma.
Retrospective Study of Postoperative Pulmonary Complications in Patients with Cervical Spine Pathology
Authors: Dube Surya Kumar , Pandia Mihir Prakash , Chaturvedi Arvind , Kumar Shailender
Published: June 2018

Background Postoperative pulmonary complication (PPC) after cervical spine surgery is known to increase patient morbidity and mortality as well as the hospital and intensive care unit (ICU) stay. However, studies addressing this issue are scarce in the current literature. The aim of this study was to find out the incidence and various factors associated with PPC in patients undergoing cervical spine surgeries.

Materials and Methods It is a retrospective study in a tertiary care hospital. Two hundred and seven patients who underwent different cervical spinal surgeries were included in this study. Various perioperative data including demography, history of smoking, associated systemic illness, type and site of lesion, preoperative respiratory status, and signs of involvement of lower cranial nerves were collected. The incidence and the risk factors for PPC were found out. Statistical analysis was done using chi-square/Fisher's exact test/Student's t-test, followed by univariate and multiple logistic regression analysis.

Results The incidence of PPC in our study was 39.6%. Various pulmonary complications observed were difficulty in breathing requiring some intervention (19.3%), pneumonia (5.3%), tracheobronchitis (3.9%), arterial desaturation (3.4%), reintubation (3.4%), atelectasis (1.3%), pleural effusion (0.97%), pneumothorax (0.97%), and acute respiratory distress syndrome (ARDS) (0.97%). Preoperative respiratory abnormality, cervical laminectomy and instrumentation surgery and postoperative mechanical ventilation of > 24 hours duration were found to be independent risk factors for occurrence of PPC.

Conclusions The patients with cervical spinal cord pathology are at increased risk for PPC. Preoperative respiratory abnormality, postoperative mechanical ventilation of > 24-hour duration, and cervical laminectomy and instrumentation surgery are independent risk factors for PPC.
Droplet networks rearrange in response to electrical ruptures
Authors: Cesare Chris
Published: June 2018

By selectively destroying interfaces between small droplets, researchers observe the formation of new network arrangements that match predictions.
Hip fracture—great steps forward but we still need better evidence. A commentary on NICE CG124 and QS16 on fractured neck of femur
Authors: Jay Roger H , Hipps Daniel
Published: June 2018

The National Institute for Health and Care Excellence (NICE) updated its Clinical Guideline and its Quality Standard on hip fracture in 2017. Three quality statements relate to the organisation of care—having a multidisciplinary hip fracture programme, and both operating and starting rehabilitation without delay—while three relate to surgical aspects, the most recent being the requirement to offer total hip replacement rather than hemiarthroplasty for those with displaced intracapsular fractures who could mobilise outdoors with a stick. Some evidence exists to support this, but the timely provision of this more complex and specialised operation presents a logistical challenge to many units. The evidence for many more general aspects of the care of hip fracture patients is still extrapolated from other populations, and more research is needed to guide the care of this specific group.
Holling Type I versus Holling Type II functional responses in Gram-negative bacteria
Authors: Nev O A , van den Berg H A
Published: June 2018

We consider how the double-membrane structure of the cell envelope of Gram-negative bacteria affects its functional response, which is the mathematical relationship that expresses how the nutrient uptake flux depends on environmental conditions. We show that, under suitable conditions, the Holling Type I functional response is a plausible model, as opposed to the Holling Type II (rectangular hyperbolic, ‘Michaelis–Menten’) response that is the default model in much of the literature. We investigate both diffusion-limited and capacity-limited regimes. Furthermore, we reconcile our findings with the preponderance in the established literature of hyperbolic models for the growth response, which are generally assumed to be valid, for both Gram-negative and Gram-positive bacteria. Finally, we consider the phenomenon of dynamic adjustment of investment of molecular building blocks in cellular components, and show how this will affect the functional response as observed by the experimenter.
United States Medical Licensing Exam Step I Score as a Predictor of Neurosurgical Career Beyond Residency
Authors: Gelinne Aaron , Zuckerman Scott , Benzil Deborah , Grady Sean , Callas Peter , Durham Susan
Published: June 2018

BACKGROUND

United States Medical Licensing Exam (USMLE) Step I score is cited as one of the most important factors when for applying to neurosurgery residencies. No studies have documented a correlation between USMLE Step I score and metrics of neurosurgical career trajectory beyond residency.

OBJECTIVE

To determine whether USMLE Step I exam scores are predictive of neurosurgical career beyond residency, as defined by American Board of Neurological Surgery (ABNS) certification status, practice type, academic rank, and research productivity.

METHODS

A database of neurosurgery residency applicants who matched into neurosurgery from 1997 to 2007 was utilized that included USMLE Step I score. Online databases were used to determine h-index, National Institutes of Health (NIH) grant funding, academic rank, practice type, and ABNS certification status of each applicant. Linear regression and nonparametric testing determined associations between USMLE Step I scores and these variables.

RESULTS

USMLE Step I scores were higher for neurosurgeons in academic positions (237) when compared to community practice (234) and non-neurosurgeons (233, P < .01). USMLE Step I score was not different between neurosurgeons of different academic rank (P = .21) or ABNS certification status (P = .78). USMLE Step I score was not correlated with h-index for academic neurosurgeons (R2 = 0.002, P = .36).

CONCLUSION

USMLE Step I score has little utility in predicting the future careers of neurosurgery resident applicants. A career in academic neurosurgery is associated with a slightly higher USMLE Step I score. However, USMLE Step I score does not predict academic rank or productivity (h-index or NIH funding) nor does USMLE Step I score predict ABNS certification status.
Intraoperative Fluorescence Cerebral Angiography by Laser Surgical Microscopy: Comparison With Xenon Microscopy and Simultaneous Observation of Cerebral Blood Flow and Surrounding Structures
Authors: Ito Yuhei , Suzuki Kyouichi , Ichikawa Tsuyoshi , Watanabe Yoichi , Sato Taku , Sakuma Jun , Saito Kiyoshi
Published: June 2018

BACKGROUND

Laser surgical microscopes should enable uniform illumination of the operative field, and require less luminous energy compared with existing xenon surgical microscopes.

OBJECTIVE

To examine the utility of laser illumination in fluorescence cerebral angiography.

METHODS

Fluorescein sodium (fluorescein) was used as a fluorescent dye. We first compared the clarity of cerebral blood flow images collected by fluorescence angiography between the laser illumination and xenon illumination methods. We then assessed use of the laser illuminator for simultaneous observation of blood flow and surrounding structures during fluorescence angiography. Furthermore, the study was designed to evaluate usefulness of the thus determined excitation light in clinical cases.

RESULTS

Fluorescence angiography using blue light laser for excitation provided higher clarity and contrast blood flow images compared with using blue light generated from a xenon lamp. Further, illumination with excitation light consisting of a combination of 3 types of laser (higher level of blue light, no green light, and lower level of red light) enabled both blood flow and surrounding structures to be observed through the microscope directly by the surgeon.

CONCLUSION

Laser-illuminated fluorescence angiography provides high clarity and contrast images of cerebral blood flow. Further, a laser providing strong blue light and weak red light for excitation light enables simultaneous visual observation of fluorescent blood flow and surrounding structures by the surgeon using a surgical microscope. Overall, these data suggest that laser surgical microscopes are useful for both ordinary operative manipulations and fluorescence angiography.
Evaluating and managing chronic idiopathic urticaria in adults
Authors: Webster Lindsay , Rider Nicholas L. , Archambault Mark E.
Published: June 2018

Chronic idiopathic urticaria (CIU), also known as chronic spontaneous urticaria, is characterized by the presence of hives on most days of the week, for 6 weeks or longer, and without an identifiable or consistent cause. Evaluation is clinical and based on the presence of episodic urticarial lesions. Although patients are subject to overtesting during the diagnosis of CIU, guidelines suggest starting with three basic laboratory tests. Treatment is a stepwise approach, involving second-generation antihistamines, histamine2 antagonists, leukotriene receptor antagonists, first-generation antihistamines, and potent antihistamines. Refractory CIU requires adding alternative agents such as omalizumab, anti-inflammatory agents, and immunosuppressants.
Val & Holly: Teaching Empathy Through an Evolving Case Study
Authors: Leiningen Cheryl , Kelly Laura
Published: June 2018

With the demand for learning required technical skills continuing to increase, nurse educators must not lose sight of the importance of assisting undergraduate nursing students to develop skills essential for creating a trusting therapeutic relationship. Teaching empathy through a semester-long family care project presented as an unfolding case study can help students understand what it is like for a patient and family to struggle with the multiple issues associated with having a chronic disease.
Getting Students to Value Leadership Early in the Nursing Curriculum: Innovation Makes It Possible
Authors: Knight Candace C. , Hamilton Sharon H.
Published: June 2018

Introducing leadership content early in a nursing program and weaving related concepts throughout the curriculum allow students opportunities to try on leadership roles and styles and become more skilled in applying leadership concepts. This article describes the implementation and revision of a personal leadership course taught early in an undergraduate nursing curriculum using service-learning, simulation, and team-based learning. The innovative delivery of the course improved student satisfaction and relevance of leadership concepts to second-semester nursing students. The course is foundational and taken in addition to the traditional management and systems leadership course.
Self-Regulated E-Learning Modules for Prenursing Success
Authors: Briscoe Gina S. , Brown Lynn G.
Published: June 2018

To be successful in their courses, nursing students must possess and routinely practice a wide range of self-regulated learning skills. Self-monitoring and regulation of cognition, metacognition, and behaviors influence learning for nursing practice. As reading and studying for comprehension, effective note taking, and taking tests successfully are challenging for many students, faculty at a rural community college created five self-regulated e-learning modules to equip prenursing students with evidence-based techniques to facilitate learning. This article describes the framework of self-regulated learning, the learning modules, student feedback, and implications for nurse educators.
Development and Validation of Simulation-Based Procedural Checklists for Evaluation of Neonatal Nurse Practitioner Performance
Authors: Jarding Laura , Hogden Laurie A. , Messier Stephen E. , Kozmenko Valeriy , Simanton Edward , Bjornson Kerri , Ortman Brockmueller Charisse
Published: June 2018

Background:

Neonatal nurse practitioner (NNP) procedural competence is essential. Procedural simulation provides opportunity to practice high-risk, low-frequency procedures and helps improve skill retention. A formal procedural simulation experience was created in an attempt to provide sufficient experience for NNPs. While preparing for the simulation experience, the group recognized the lack of validated competency metrics for most neonatal intensive care unit (NICU) procedures.

Purpose:

The purpose of this study was to create and validate procedural checklists measuring competence of NNPs participating in simulated performance of 9 high-risk NICU procedures.

Methods:

IRB approval was obtained and NNPs agreed to data collection. A self and peer assessment tool was developed and distributed to NNPs, nurses, and neonatologists to gather a baseline perception of procedural competency. Procedural checklists were then developed to measure/assess individual skills against a standard. Benchmark videos were created to demonstrate the standard approach to procedural performance. Each procedural skill performed by the NNP participant was scored by 3 individual evaluators: once in real time and twice by video recording analysis.

Findings/Results:

A Cronbach α was used to measure the reliability and validity of the procedural checklists. Comparison was made between live grading and video-based grading scores using analysis of variance. Difference between grading modalities was less than 3% and nonsignificant for 8 of 9 procedures. No significant difference was found between individual graders for any of the skills being evaluated and suggested high interrater reliability of the checklists.

Implications for Practice:

Objective, standardized procedural checklists are valid tools to evaluate NNP procedural skills in simulation. Procedural simulation experiences help strengthen skills, improve performance, and possibly improve patient outcomes.
Comparing N-PASS and NIPS
Authors: Desai Amita , Aucott Susan , Frank Karen , Silbert-Flagg JoAnne
Published: June 2018

Background:

Proper assessment of pain is essential to allow for safe and compassionate care of infants in the neonatal intensive care unit (NICU). The Neonatal Infant Pain Scale (NIPS) used in an urban level IV NICU addresses acute pain but may not adequately measure chronic neonatal pain.

Purpose:

The purpose of this quality improvement study was to improve acute and chronic pain measurements for neonates in an NICU through implementation of the Neonatal Pain, Agitation, and Sedation Scale (N-PASS).

Methods/Search Strategy:

An evidence search for a comprehensive tool to assess neonatal pain in the setting of a 45-bed level IV NICU was completed. The N-PASS was found to be inclusive of measuring acute and chronic neonatal pain. Participants for a quality improvement study, including NICU nurses and providers, were educated on the N-PASS. Nurses documented in the N-PASS and the NIPS during routine pain assessments for NICU infants for comparison. Participants completed a survey assessing knowledge of the N-PASS.

Findings/Results:

When compared, the N-PASS generated 98% of pain scores greater than the NIPS. Surveys demonstrated an increase in staff knowledge for the N-PASS.

Implications for Practice:

Implementation of a multidimensional pain tool that measures acute and chronic pain is essential for proper pain assessment. Providers can manage neonatal pain when accurate documentation is available.

Implications for Research:

Further research evaluating guided management of acute and chronic pain scores on the N-PASS would aid hospital policies on therapies for neonatal pain.
Evolution of Delivery Room Management for Meconium-Stained Infants
Authors: Chabra Shilpi
Published: June 2018

Background:

The approach to intrapartum and postnatal management of an infant born through meconium-stained amniotic fluid (MSAF) in the delivery room (DR) has changed several times over the last few decades, leading to confusion and anxiety among health care providers (nurses, nurse practitioners, respiratory therapists, midwives, and physicians). This article provides state-of-the-art insight into the evidence or lack thereof for the changes in guidelines.

Purpose:

To discuss the evidence for evolution of DR management of vigorous and nonvigorous infants born through any type of MSAF.

Methods:

Review of guidelines from the Neonatal Resuscitation Program of the American Academy of Pediatrics and the American College of Obstetricians and Gynecologists, the International Liaison Committee on Resuscitation, Consensus on Science and Treatment Recommendations, and textbooks of neonatal resuscitation and research using MEDLINE via PubMed.

Findings:

In pregnancies complicated by MSAF, intrapartum suctioning of the oro- and nasopharynx and postnatal intubation with tracheal suctioning of infants have been traditionally used to clear the airway and decrease meconium aspiration syndrome. The recommendations for these perinatal practices have changed several times due to some evidence that the procedures are not beneficial and may even be harmful.

Implications for Practice:

Intrapartum suctioning and postnatal tracheal suctioning of infants (vigorous or nonvigorous) born through MSAF are not recommended. This is a “high-risk” delivery requiring 2 team members to be present at birth—one with full resuscitation skills including tracheal intubation.

Implications for Research:

Need to evaluate effects of discontinuing the practice of tracheal suctioning in nonvigorous infants on the incidence of meconium aspiration syndrome and neonatal mortality.
Introduction of Continuous Video EEG Monitoring into 2 Different NICU Models by Training Neonatal Nurses
Authors: Goswami Ipsita , Bello-Espinosa Luis , Buchhalter Jeffrey , Amin Harish , Howlett Alexandra , Esser Michael , Thomas Sumesh , Metcalfe Cathy , Lind Jan , Oliver Norma , Kozlik Silvia , Mohammad Khorshid
Published: June 2018

Background:

Continuous video electroencephalographic (EEG) (cvEEG) monitoring is emerging as the standard of care for diagnosis and management of neonatal seizures. However, cvEEG is labor-intensive and the need to initiate and interpret studies on a 24-hour basis is a major limitation.

Purpose:

This study aims at establishing consistency in monitoring of newborns admitted to 2 different neonatal intensive care units (NICUs) managed by the same neurocritical care team.

Methods:

Neonatal nurses were trained to apply scalp electrodes, troubleshoot technical issues, and identify amplitude-integrated EEG abnormalities. Guidelines, checklists, and visual training modules were developed. A central network system allowed remote access to the cvEEGs by the epileptologist for timely interpretation and feedback. A cohort of 100 infants with moderate to severe hypoxic-ischemic encephalopathy before and after the training program was compared.

Results:

During the study period, 192 cvEEGs were obtained. The time to initiate brain monitoring decreased by 31.5 hours posttraining; this, in turn, led to an increase in electrographic seizure detection (20% before vs 34% after), decrease in seizure clinical misdiagnosis (65% before and 36% after), and reduction in antiseizure medication burden.

Implications for Practice:

Training experienced NICU nurses to set up, start, and monitor cvEEGs can decrease the time to initiate cvEEGs, which may lead to better seizure diagnosis and management.

Implications for Research:

Further understanding of practice bundles for best supporting infants at risk and being treated for seizures needs to be evaluated for integration into practice.

Video Abstract Available at
https://journals.lww.com/advancesinneonatalcare/Pages/videogallery.aspx.
Comparison of Neonatal Nursing Practices for Determining Feeding Tube Insertion Length and Verifying Gastric Placement With Current Best Evidence
Authors: Parker Leslie A. , Withers Jessica H. , Talaga Elizabeth
Published: June 2018

Background:

Oral-nasogastric feeding tubes (FTs) are often malpositioned, placing infants at risk for complications. Confusion exists regarding the accuracy of methods to determine FT insertion length and verify gastric FT placement, and it is unknown whether evidence-based methods are used by neonatal nurses.

Purpose:

To compare individual and unit-based neonatal nursing practices regarding methods used to determine FT insertion length and verify gastric FT placement.

Methods:

Neonatal nurses were surveyed about individual and unit-based practices regarding methods used to determine FT insertion length and verify gastric FT placement in infants in the neonatal intensive care unit.

Results:

Sixty neonatal nurses completed the survey, with 63% utilizing the nose-ear-midway to the umbilicus method, which was included in 50% of protocols and is associated with up to a 90% accuracy rate. Although it has an unacceptably high inaccuracy rate, the nose-to-ear-to-xiphoid method was used by 32% of nurses and recommended in 30% of protocols. To verify gastric FT placement, 98% of nurses used auscultation of a whoosh sound and 83% used aspiration of gastric contents. Neither verification method is supported by evidence or recommended for use.

Implications for Practice:

A lack of consistency exists between nursing practice and evidence-based methods.

Implications for Research:

Research is needed to determine more accurate and reliable ways to determine FT insertion depth and verify gastric FT placement in neonates.
Interpregnancy Interval and Singleton Live Birth Outcomes From In Vitro Fertilization
Authors: Quinn Molly M. , Rosen Mitchell P. , Huddleston Heather G. , Cedars Marcelle I. , Fujimoto Victor Y.
Published: June 2018

OBJECTIVE:

To describe the relationship between a short interpregnancy interval and adverse pregnancy outcomes in the population undergoing assisted reproductive technology.

METHODS:

This is a retrospective analysis using data from the Society for Assisted Reproductive Technology Clinic Outcome Reporting System. The cohort includes patients with a history of live birth from assisted reproductive technology who returned for a fresh, autologous in vitro fertilization (IVF) cycle from 2004 to 2013. Interpregnancy interval was defined as the interval from live birth to cycle start. Logistic regression models of preterm delivery (less than 37 weeks of gestation) and low birth weight (less than 2,500 g) on interpregnancy interval were fit with adjustment for age, body mass index, and history of preterm delivery. Predicted probabilities were generated from the logistic model.

RESULTS:

Of 51,997 fresh IVF cycles after an index live birth, 17,536 resulted in a repeat live birth with 11,271 singleton live births from autologous IVF. An interpregnancy interval of less than 18 months occurred in 40.9% of cycles. Compared with a reference interpregnancy interval of 12 to less than 18 months, the adjusted odds ratio for singleton preterm delivery was 1.66 (95% CI 1.05–2.65) for an interpregnancy interval less than 6 months and 1.34 (95% CI 1.06–1.69) for 6 to less than 12 months. An interpregnancy interval 6 to less than 12 months was associated with a 3.0% increase in preterm delivery (13.6±1.1% vs 10.6±0.7%, P=.030) and a 2.7% increase in low birth weight (8.0±0.9% vs 5.3±0.5%, P=.025) compared with an interpregnancy interval of 12 to less than 18 months.

CONCLUSION:

In this nationally representative population, an interval from delivery to treatment start of less than 12 months is associated with increased rates of preterm delivery and low birth weight in singleton live births from assisted reproductive technology. The data support delaying the start of IVF treatment 12 months from a live birth, but do not suggest a benefit from a longer interval as has been recommended for naturally conceiving couples.