Core outcome set for perinatal interventions for congenital diaphragmatic hernia

OBJECTIVE

To develop a core set of prenatal and neonatal outcomes for clinical studies evaluating perinatal interventions for congenital diaphragmatic hernia, using a validated consensus-building method.

METHODS

An international steering group comprising 13 leading maternal-fetal medicine specialists, neonatologists, pediatric surgeons, patient representatives, researchers and methodologists guided the development of this core outcome set. Potential outcomes were collected through a systematic review of the literature and entered into a two-round online Delphi survey. A call was made for stakeholders with experience of congenital diaphragmatic hernia to review the list and score outcomes based on their perceived relevance. Outcomes that fulfilled the consensus criteria defined a priori were discussed subsequently in online breakout meetings. Results were reviewed in a consensus meeting, during which the core outcome set was defined. Finally, the definitions, measurement methods and aspirational outcomes were defined in online and in-person definition meetings by a selection of 45 stakeholders.

RESULTS

Overall, 221 stakeholders participated in the Delphi survey and 198 completed both rounds. Fifty outcomes met the consensus criteria and were discussed and rescored by 78 stakeholders in the breakout meetings. During the consensus meeting, 93 stakeholders agreed eventually on eight outcomes, which constituted the core outcome set. Maternal and obstetric outcomes included maternal morbidity related to the intervention and gestational age at delivery. Fetal outcomes included intrauterine demise, interval between intervention and delivery and change in lung size in utero around the time of the intervention. Neonatal outcomes included neonatal mortality, pulmonary hypertension and use of extracorporeal membrane oxygenation. Definitions and measurement methods were formulated by 45 stakeholders, who also added three aspirational outcomes: duration of invasive ventilation, duration of oxygen supplementation and use of pulmonary vasodilators at discharge.

CONCLUSIONS

We developed with relevant stakeholders a core outcome set for studies evaluating perinatal interventions in congenital diaphragmatic hernia. Its implementation should facilitate the comparison and combination of trial results, enabling future research to better guide clinical practice. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Permeability of blood-tear barrier to fluorescein and albumin after application of platelet-activating factor to the eye of the guinea pig

One of the inflammatory responses of the eye to local application of platelet-activating factor (PAF) is oedema of the conjunctiva, caused by extravasation of plasma. Aim of the study was to investigate if fluorescein would leak from the blood into the tears together with plasma protein after application of PAF to the eye. Fluorescein was given intraperitoneally 30 min prior to application of 25 μl of 0.1% solution of PAF. Thirty min after PAF the tear film was collected by washing the surface of the eye with 25 μl of phosphate buffered saline (PBS). Fluorescein in eye washings and in plasma was measured by fluorophotometry and albumin by immunodiffusion. Both fluorescein and albumin appeared in a related fashion in tears, being absent in washings of placebo-treated control eyes. Extravasation of fluorescein can be used as a measure for plasma leakage in the conjunctiva with the advantage over the Evans Blue method that the former is a non-invasive method.

Interaction between nitric oxide and prostaglandin synthesis in the acute phase of allergic conjunctivitis

Both nitric oxide and prostaglandins induce vasodilatation which is an important feature of local inflammation. The purpose of the study described here was to investigate a possible interaction between these two types of mediators in an experimental model of allergic conjunctivitis. A conjunctival allergic reaction was induced with antigen in sensitized guinea pigs. Conjunctival vascular permeability changes were evaluated with the prophylactic use of an inhibitor of nitric oxide synthase (L-NAME) and a cycloxygenase inhibitor (indomethacin). To study a possible interaction between nitric oxide and prostaglandin synthesis in the acute phase of allergic conjunctivitis, the levels of nitrite and PGE2 were determined in lavage fluid. The prophylactic use of L-NAME on the formation of conjunctival edema in response to topical PGD2 administration was studied by measurement of albumin levels in lavage fluid. Both nitric oxide and PGE2 are synthesized in response to antigen provocation and after histamine administration. Nitric oxide and PGE2 are produced simultaneously in the conjunctiva and they showed identical synthesis profiles in response to antigen provocation. Pretreatment with L-NAME inhibited the synthesis of PGE2 whereas exogenous administration of nitric oxide increased the level of PGE2 in lavage fluid. Prophylactic treatment with L-NAME significantly inhibited the PGD2 induced albumin extravasation. Nitric oxide seems to play an important role in the acute phase of allergic conjunctivitis it may stimulate PGE2 production and acts as a secondary mediator in PGD2 and histamine induced conjunctival edema.

Analysis of human tear fluid components, inhibiting protein adhesion to plastic surfaces

In a previous paper we reported the presence of components in human tear fluid that block the interaction of proteins with plastic surfaces, interfering with tear protein ELISA and proposed the term coating inhibiting activity. The purpose of the study presented here was to further analyse these components. Coating inhibitory activity in human reflex tears was analysed by lectin affinity chromatography, using the agarose bound lectin Artocarpus integrifolia agglutinin (Jacalin), gel filtration, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), blotting and Jacalin staining. For coating inhibitory activity assay in experimental tear samples, the binding of the protein Avidin-conjugated horseradish peroxidase to the polystyrene surface of ELISA micro-titer plate wells, preincubated with the experimental tear samples was measured. In addition, tears were incubated with scrapings of the ELISA plates used in the assay and with six different types of contact lenses (two rigid gas permeable and four hydrogel soft contact lenses) for analysis of adsorbed components. Lectin affinity chromatography of tears yielded a Jacalin-binding and a non-Jacalin-binding preparation, both exhibiting coating inhibitory activity but representing chemically different preparations as observed by SDS-PAGE. After performing gel filtration, coating inhibitory activity eluted with similar retention in both preparations. In fractions exhibiting activity, tear proteins of low molecular weight (< 40 kDa) were detected. Among these, two Jacalin-binding glycoproteins were detected; a major component of approximately 28 kDa and a somewhat smaller minor component. All low molecular weight components were also detected on the scrapings, incubated with tears. The possibility that coating inhibitory activity in tears might reside in a component of larger molecular size can however not be excluded. The human tear proteins secretory Immunoglobulin A, lactoferrin and lysozyme are not involved in coating inhibition. On one of the two rigid gas permeable contact lenses incubated with the tears, the 28 kDa glycoprotein was detected. From the data obtained in our study we conclude that coating inhibitory activity in tears seems to be associated with multiple components of low molecular weight.

Nitric oxide plays a role as a mediator of conjunctival edema in experimental allergic conjunctivitis

The role of nitric oxide in allergic conjunctivitis was studied in a guinea pig model. The eyes of sensitized guinea pigs were challenged with ovalbumin (20 micrograms per eye) or histamine (20 micrograms per eye). Synthesis of nitric oxide (NO) was inhibited using L-NAME (200 micrograms per eye) or aminoguanidine (200 micrograms per eye). The formation of conjunctival edema was graded and levels of nitrite, a breakdown product of nitric oxide were measured in lavage fluid. Conjunctival vasopermeability was determined by measuring the albumin concentration in the fluid on the surface of the eye (lavage fluid). Animals were treated with sodium nitroprusside (SNP) or phenylephrine after which histamine induced conjunctival vasopermeability changes were measured. Drugs were administered topically with the other eye serving as a control. Both ovalbumin and histamine produced a marked inflammatory response including hyperaemia and edema. At the top of the inflammatory response occurring 30 min after challenge, increased levels of nitrite, a breakdown product of NO, were measured in lavage fluid. Prophylactic treatment with L-NAME or aminoguanidine resulted in a significant inhibition of the NO synthesis. Both L-NAME and aminoguanidine decreased conjunctival vascular permeability and edema formation significantly. Administration of SNP resulted in a marked dilatation of conjunctival blood vessels and produced a dose-dependent increase of vascular permeability. Addition of SNP to histamine significantly enhanced conjunctival edema and potentiated vascular permeability. These results indicate that NO is produced in the acute phase of allergic conjunctivitis and mediates vasodilatation after topical provocation with ovalbumin or histamine in sensitized guinea pigs. The resulting increase of the conjunctival blood flow subsequently increases the vascular permeability and enhances conjunctival edema formation. Inhibition of NO synthesis leads to a reduction of conjunctival hyperaemia and subsequently reduces the formation of edema.

Nitric oxide induces vascular permeability changes in the guinea pig conjunctiva

The role of nitric oxide (NO) as an inflammatory mediator in the mechanism of increased microvascular permeability was examined in a guinea pig model of allergic conjunctivitis. Topical challenge with antigen, compound 48/80, histamine or platelet activating factor (PAF) resulted in a marked increase of the conjunctival vascular permeability. Vascular permeability was determined by measuring the albumin content in the lavage fluid of the challenged eyes after 30 min. Pretreatment with NG-nitro-L-arginine methyl ester (L-NAME) eyedrops caused a significant inhibition of the clinical score and the vascular permeability after challenge with either antigen, histamine or PAF. Aminoguanidine prophylaxis also resulted in a significant inhibition of both the clinical score and vascular permeability in response to all the used provocative agents except PAF. Our observations indicate that NO is an important factor in the induction of the vascular permeability provoked by histamine but seems to play no role in the mechanism by which PAF exerts increased vascular permeability in the conjunctiva.

Cutaneous hypersensitivity responses in chickens divergently selected for antibody responses to sheep red blood cells

Cellular immunity in vivo of chickens selected for high and low antibody responses to SRBC was evaluated by primary and secondary cutaneous hypersensitivity reactions to BSA and phytohemagglutinin (PHA)-induced delayed-type hypersensitivity (DTH). Similar to PHA-induced DTH, primary and secondary cutaneous hypersensitivity to BSA comprised acute (1- and 2-h), intermediate (4- and 6-h), and late (24-h) wing web swelling responses. Primary and secondary hypersensitivity to BSA revealed line differences between the High (H) line and a randombred Control (C) line on the one hand, and the Low (L) line on the other hand. Hypersensitivity to BSA was almost absent or decreased in the L line. The late phase of PHA-induced DTH was significantly elevated in the H line as compared with the L line. Naive recipients sensitized systematically with either serum from chickens sensitized with BSA, or with BSA-binding IgG, developed an antigen-specific early wing web swelling response following local challenge with BSA. It is suggested that the acute component of cutaneous hypersensitivity is mediated by Ig. The acute response may be a prerequisite for the development of classical (late) cutaneous DTH responses or may be initiated simultaneously with DTH. The current results indicate that the selection did not result in a higher hypersensitivity response to another T cell-dependent antigen and a mitogen in the H line, but in a lower response in the L line.

Separation and characteristics of glycoproteins in tears which inhibit coating and precipitation of protein

Using a modified turbidimetric assay to determine the protein concentration in human tears by precipitation with trichloroacetic acid (TCA) we found lower protein concentrations if compared with other methods for protein determination. This implies that a factor in human tears is able to inhibit the precipitation of protein by TCA. Earlier a coating inhibitory factor in human tears was described which is able to prevent coating of a polyacrylate surface by proteins using a ELISA methodology. Because of the similarity in its behaviour towards protein we investigated whether the same factor could be responsible for both inhibitory effects. A pool of human tears was separated into various fractions using HPLC whereafter inhibitory activity in the turbidimetric and the coating assay could be found in the same fractions. Characterization of the inhibitory factor was performed by minigel-electrophoresis (SDS-PAGE), after which blotting and staining with a lectin (Jacalin) revealed two subunits of a glycoprotein with a molecular weight of 30 and 70 kD. The inhibitory factor also could be isolated if human tears were incubated for 30 min at 100 degrees C whereafter precipitated protein was removed by centrifugation. Inhibitory activity could be detected in the supernatant and an identical glycoprotein profile could be produced after staining with lectin (Jacalin). The results of this study suggest that a soluble glycoprotein serves as a coating and precipitation inhibitor in tears and may play an important role in the protein to protein interaction on the surface of the eye.

N-acetyl-aspartyl glutamic acid (NAAGA) topical eyedrops in the treatment of giant papillary conjunctivitis (GPC)

Giant Papillary Conjunctivitis (GPC) is a conjunctival inflammatory condition associated with contact lens wear. The etiology is still unknown and no adequate treatment is found. Mastcell stabilizing drugs are useful in the treatment of chronic inflammatory processes. The effect of 6% N-acetyl-aspartyl glutamic acid (NAAGA), a mastcell stabilizing agent, in a double-masked comparative trial with placebo in the treatment of GPC is reported. Seventeen patients with symptomatic GPC were treated over a four week period, eyes were randomized to receive NAAGA or placebo. A decrease in symptoms was found for both eyes. No significant difference of clinical symptoms and signs were observed between NAAGA or placebo treated eyes. These results suggest a wash effect of placebo in GPC. Tear C3a showed a increased level compared to normals but no statistically significance was observed in our study. The results of this study indicate that mastcell stabilization in GPC has little effect and treatment should be focused more on inflammatory mediators released because of mechanical stimuli.

Percutaneous antegrade fiberoptic ureterorenoscopic treatment of ureteral calculi

Treatment of upper ureteral calculi can be accomplished by various endourological techniques and/or extracorporeal shock wave lithotripsy. Percutaneous fiberoptic treatment of upper ureteral stones provides an alternative especially suited as second line treatment in cases when extracorporeal shock wave lithotripsy failed. Usually, these patients will present with impacted ureteral stones. Our first experiences with 8 stones in 7 patients to date proved this technique to be safe and reliable, with no complications encountered on excretory urography 3 months postoperatively.

Arthrographic differential diagnosis between ruptures of the anterior talofibular ligament, the joint capsule and the anterior tibiofibular ligament

From literature study, surgical findings and cadaver experiments, it is unlikely that, in an inversion type ankle sprain, rupture of the anterior tibiofibular ligament frequently accompanies rupture of the capsule and the lateral ligaments. Contrary to the experience of other authors, we found the presence or absence of a) a contrast-free zone, b) the tibiofibular recess, or c) both together, on ankle arthrography in no way indicative of a rupture of the anterior tibiofibular ligament. Contrast leakage out of the joint into the soft tissues without leakage below and lateral to the lateral malleolus indicates rupture of the joint capsule. Leakage below and lateral to the lateral malleolus indicates rupture of the anterior talofibular ligament. The anatomic relationships between the syndesmosis, the joint capsule, the tibiofibular recess and the anterior talofibular recess and the anterior talofibular ligament were studied on cadavers and during surgery. Contrast spread in the soft tissues is probably determined by the arrangement of and damage to the soft tissues and by the size of the haematoma and follows the path of least resistance.

Teaching medical English to foreign-language doctors

Acquisition of an advanced medical degree beyond licensure and specialization is advantageous and encouraged in Swedish medical education. Since a thesis and a number of published works, usually in English are required, there is considerable interest in medical writing by doctors and medical scientists. A voluntary course in 'Biomedical Authorship' which included presentation of oral reports was offered by the Karolinska Institutes' Medical Faculty. This course was intended to prepare participants for their thesis work and for presentations at scientific congresses. The course revealed that the principle difficulty was not in English skills which were rather good, but in the students' inexperience in critically rereading what they had written and making suitable revisions. A case study method was used so that students acquired experience in critically reading and correcting their own work and that of others. An instructor who understood the evolution of academic Swedish was of considerable help in explaining some of the 'Swenglishisms' that arose during the course. The oral presentation portion, which used videotapes of students, showed the students as lacking experience in basic public speaking and as frequently being apprehensive. This was much improved by taped poetry readings, scientific reports and slide shows. This Swedish experience should apply to teaching biomedical writing in the other Scandinavian countries and in Northern Europe.