The VEGF-A exon 8 splicing-sensitive fluorescent reporter mouse is a novel tool to assess the effects of splicing regulatory compounds in vivo.

Vascular endothelial growth factor (VEGF)-A is differentially spliced to give two functionally different isoform families; pro-angiogenic, pro-permeability VEGF-Axxx and anti-angiogenic, anti-permeability VEGF-Axxxb. VEGF-A splicing is dysregulated in several pathologies, including cancer, diabetes, and peripheral arterial disease. The bichromatic VEGF-A splicing-sensitive fluorescent reporter harboured in a transgenic mouse is a novel approach to investigate the splicing patterns of VEGF-A in vivo. We generated a transgenic mouse harbouring a splicing-sensitive fluorescent reporter designed to mimic VEGF-A terminal exon splicing (VEGF8ab) by insertion into the ROSA26 genomic locus. dsRED expression denotes proximal splice site selection (VEGF-Axxx) and eGFP expression denotes distal splice site selection (VEGF-Axxxb). We investigated the tissue-specific expression patterns in the eye, skeletal muscle, cardiac muscle, kidney, and pancreas, and determined whether the splicing pattern could be manipulated in the same manner as endogenous VEGF-A by treatment with the SRPK1 inhibitor SPHINX 31. We confirmed expression of both dsRED and eGFP in the eye, skeletal muscle, cardiac muscle, kidney, and pancreas, with the highest expression of both fluorescent proteins observed in the exocrine pancreas. The ratio of dsRED and eGFP matched that of endogenous VEGF-Axxx and VEGF-Axxxb. Treatment of the VEGF8ab mice with SPHINX 31 increased the mRNA and protein eGFP/dsRED ratio in the exocrine pancreas, mimicking endogenous VEGF-A splicing. The VEGF-A exon 8 splicing-sensitive fluorescent reporter mouse is a novel tool to assess splicing regulation in the individual cell-types and tissues, which provides a useful screening process for potentially therapeutic splicing regulatory compounds in vivo.

Improved predictive diagnosis of diabetic macular edema based on hybrid models: An observational study.

Diabetic Macular Edema (DME) is the most common sight-threatening complication of type 2 diabetes. Optical Coherence Tomography (OCT) is the most useful imaging technique to diagnose, follow up, and evaluate treatments for DME. However, OCT exam and devices are expensive and unavailable in all clinics in low- and middle-income countries. Our primary goal was therefore to develop an alternative method to OCT for DME diagnosis by introducing spectral information derived from spontaneous electroretinogram (ERG) signals as a single input or combined with fundus that is much more widespread. Baseline ERGs were recorded in 233 patients and transformed into scalograms and spectrograms via Wavelet and Fourier transforms, respectively. Using transfer learning, distinct Convolutional Neural Networks (CNN) were trained as classifiers for DME using OCT, scalogram, spectrogram, and eye fundus images. Input data were randomly split into training and test sets with a proportion of 80 %-20 %, respectively. The top performers for each input type were selected, OpticNet-71 for OCT, DenseNet-201 for eye fundus, and non-evoked ERG-derived scalograms, to generate a combined model by assigning different weights for each of the selected models. Model validation was performed using a dataset alien to the training phase of the models. None of the models powered by mock ERG-derived input performed well. In contrast, hybrid models showed better results, in particular, the model powered by eye fundus combined with mock ERG-derived information with a 91 % AUC and 86 % F1-score, and the model powered by OCT and mock ERG-derived scalogram images with a 93 % AUC and 89 % F1-score. These data show that the spontaneous ERG-derived input adds predictive value to the fundus- and OCT-based models to diagnose DME, except for the sensitivity of the OCT model which remains the same. The inclusion of mock ERG signals, which have recently been shown to take only 5 min to record in daylight conditions, therefore represents a potential improvement over existing OCT-based models, as well as a reliable and cost-effective alternative when combined with the fundus, especially in underserved areas, to predict DME.

Evaluation of an AI system for the detection of diabetic retinopathy from images captured with a handheld portable fundus camera: the MAILOR AI study.

OBJECTIVES: To evaluate the performance of an artificial intelligence (AI) system (Pegasus, Visulytix Ltd., UK*) at the detection of diabetic retinopathy (DR) from images captured by a handheld portable fundus camera. METHODS: A cohort of 6404 patients (~80% with diabetes mellitus) was screened for retinal diseases using a handheld portable fundus camera (Pictor Plus, Volk Optical Inc., USA) at the Mexican Advanced Imaging Laboratory for Ocular Research. The images were graded for DR by specialists according to the Scottish DR grading scheme. The performance of the AI system was evaluated, retrospectively, in assessing referable DR (RDR) and proliferative DR (PDR) and compared with the performance on a publicly available desktop camera benchmark dataset. RESULTS: For RDR detection, Pegasus performed with an 89.4% (95% CI: 88.0-90.7) area under the receiver operating characteristic (AUROC) curve for the MAILOR cohort, compared with an AUROC of 98.5% (95% CI: 97.8-99.2) on the benchmark dataset. This difference was statistically significant. Moreover, no statistically significant difference was found in performance for PDR detection with Pegasus achieving an AUROC of 94.3% (95% CI: 91.0-96.9) on the MAILOR cohort and 92.2% (95% CI: 89.4-94.8) on the benchmark dataset. CONCLUSIONS: Pegasus showed good transferability for the detection of PDR from a curated desktop fundus camera dataset to real-world clinical practice with a handheld portable fundus camera. However, there was a substantial, and statistically significant, decrease in the diagnostic performance for RDR when using the handheld device.

The action of inhalation anesthetics upon the lower oesophageal sphincter.

The lower oesophageal sphincter plays an important role as a gastro-oesophageal blocker. Its proper function as a reflux barrier for the prevention of regurgitation and aspiration during anesthesia is very important. Therefore the effect of inhalation anesthetics upon the lower oesophageal sphincter is of great interest. In 10 healthy volunteers we studied the action of various inhalation anesthetics upon the lower oesophageal sphincter, the distal oesophagus and the stomach. The inhalation of nitrous oxide-oxygen alone or in combination with 2 Vol. % halothane or enflurane resulted in a highly significant pressure drop (p < 0.001) at the lower oesophageal sphincter. All three anesthetics (nitrous oxide-oxygen, nitrous oxide-oxygen-halothane and nitrous oxide-oxygen-enflurane) caused a pressure rise at the distal oesophagus and a pressure decrease at the stomach.

The effect of premedicants upon the lower oesophageal sphincter.

The barrier function of the lower oesophageal sphincter is of great practical importance in the prevention of regurgitation and aspiration. The action of seven most commonly used premedicants upon the lower oesophageal sphincter was studied in ten healthy volunteers. The results were compared with a placebo injection in eight volunteers. Sodium pentobarbital, droperidol and triflupromazine increased the presenting pressure of the lower oesophageal sphincter. Decreases were observed after promethazine, pethidine, the combination of droperidol plus fentanyl and atropine.

Management of potentially fatal alcohol intoxication.

Severely alcohol intoxicated patients pass through all stages of anesthesia according to the Guedel classification. Additional illnesses or injuries might be present, however. These require careful investigation. Blood alcohol levels are no criterion for the degree of intoxication. The treatment varies and is based on clinical symptoms. In our series of more than 100 alcohol intoxicated patients the treatment generally consisted o Apomorphine, unless unconsciousness was present, and peripheral vasopressors, if necessary. Occasionally endotracheal intubation was required. On gastric aspiration via nasogastric tube only minimal amounts of alcohol could be recovered. With correct diagnosis and effective treatment the cure rate of acute alcohol intoxication should be as high as that of other intoxications.

[Visual function evaluation in human immunodeficiency virus carriers]. / Funciones visuales en portadores del virus de inmunodeficiencia humana.

OBJECTIVE: To determine whether there are changes in the peripapillary nerve fibre layer, in colour vision, contrast sensitivity, dark adaptation and electroretinography changes in these patients who do not have infectious retinitis. METHODS: We studied 52 patients without ocular pathology; the mean age was 35.88 years old. RESULTS: We observed less thickness in all quadrants, except the nasal. The colour vision was altered in 27.77% of the patients. The contrast sensitivity test showed high frequency alterations. There was no statistically significant difference in the electroretinography test or in dark adaptation. CONCLUSIONS: There are changes in the peripapillary nerve fibre layer thickness; also we found changes in colour vision, contrast sensitivity and a decreasing trend of the B wave in the electroreninogram.

[Ethylene oxide residues and aeration time after use of modern heated aerators (author's transl)]. / Athylenoxid-Rückstände und Ausgasungszeiten bei Anwendung moderner erhitzter Lüfter.

The aeration time after ethylene oxide sterilization is rather long, particularly for PVC materials. It can be shortened enormously by heated aerators with continuous air exchange. We used different aeration methods and determined the ethylene oxide residues in endotracheal tubes, nasal and oro-pharyngeal airways, breathing tubes, parts of heart-lung-machines as well as gastroscope- and bronchoscope linings. The analyses were performed with a Hewlett-Packard gas chromatograph by the head space method. Intermittent vacuum with air irrigation was not as effective as continuous air exchange in heated aerators. The aeration time in these at 37 degrees C is longer than with 62 degrees C. After degassing in aerators with 62 degrees C the sterilized items can be used the next day already. Aerators blow the released ethylene oxide residues into the open air. The personnel is exposed to considerably smaller ethylene oxide concentrations because the long aeration time at room temperature in storage places is now eliminated.

[The toxic effect of ethylene chlorohydrin and ethylene glycol on experimental animals and human cell cultures (author's transl)]. / Die toxische Wirkung von Athylenchlorhydrin und Athylenglykol im Tierversuch und auf menschliche Zellkulturen.

Ethylene chlorohydrin (2-chlorethanol) and ethylene glycol can originate as by-products during ethylene oxide sterilization. We studied the effect of these subsdtances upon human HeLa cells as well as the conjunctiva and the epithelium of the external genitalia of 35 rabbits. - We found ethylene chlorohydrin to be considerably more toxic than ethylene glycol. 2-chloroethanol did not cause any reactions at our cell cultures in dilutions of 1:100 after 4 h action upon the cells and 24 h observation time. In our experimental animals this concentration had only minimal irritating effects at the external genitalia. Ethylene glycol produced cellular damages in dilutions of 1:10 after 5 d only. Our experimental animals showed no reactions to these concentrations. At the conjunctiva of rabbits dilutions of 1:100 ethylene chlorohydrin and 1:10 ethylene glycol had no effect. After application of 2-chloroethanol 1:100 to the external genitalia minimal irritations were observed. Ethylene glycol in dilutions of 1:5 caused irritations of the conjunctiva and the genitalia of our rabbits. Ethylene chlorohydrin- and ethylene glycol concentrations which had a damaging effect upon our cell cultures of our experimental animals were many times higher than those which might be expected to originate during ethylene oxide sterilization.

[Gamma-rays and ethylene oxide sterilization (author's transl)]. / Gamma-Strahlen und Athylenoxid-Sterilisation.

For many years there was doubt if gamma-irradiated PVC materials could be sterilized with ethylene oxide. It was feared that toxic concentrations of ethylene chlorohydrin (2-chlorethanol) might originate with this procedure. We investigated the various possibilities of ethylene chlorohydrin formation. Gamma-irradiated PVC tubes were resterilized with ethylene oxide and the 2-chlorethanol concentrations determined by gas chromatography. The 2-chlorethanol concentrations at the end of sterilization ranged from 240 to 436 ppm depending upon the composition of the tubes. After 4 d they ranged from < 5 to 280 ppm and after 21 d from < 5 to 218 ppm. For comparison were examined PVC tubes which were not gamma-irradiated but ethylene oxide sterilized only. We extracted < 5 to 23 ppm ethylene chlorohydrin from them. PVC tubes gas sterilized only and retaining 44 to 9300 ppm ethylene oxide were submerged in physiological NaCl solution for 2 h. The ethylene chlorohydrin concentrations formed by this procedure ranged from 43 to 75 ppm. After 4 d aeration before begin of extraction they decreased to < 5, 10 and 16 ppm. PVC tubes aerated for 5 or 7 d, containing at least 236 ppm ethylene chlorohydrin did not demonstrate any effect upon cultures of human fibroblasts. The toxic concentrations of 2-chlorethanol in our own animal- and cell culture experiments were 12 000 ppm or higher. Other investigators found no damaging effect on mouse fibroblasts by adding 20 000 ppm ethylene chlorohydrin. It appears to be sufficiently proven that gamma-irradiated PVC items may be resterilized with ethylene oxide and used in patients provided they they have been adequately aerated.

[Mutagenic and cytotoxic effect of ethylene oxide on human cell cultures (author's transl)]. / Mutagene und zytotoxische Wirkung von Athylenoxid auf menschliche Zellkulturen.

Certain ethylene-oxide residues in sterilized equipment can cause toxic effects in patients. Mutagenic effects of ethylene-oxide have also been described in experimental animals, plants, and bacteria. In our studies an increase of sister chromatid exchange (SCE's) served as indicator for a mutagenic effect of this substance. We cultivated fibroblasts of healthy volunteers and added liquid ethylene oxide in concentrations of 3.6 to 3600 ppm to them. In additional cell cultures we placed endotracheal tubes containing 12 to 3900 ppm ethylene oxide residues on top of the cell layers. After 24 h reaction time the cell cultures were read microscopically and the SCE ratios determined also. Liquid ethylene oxide in concentrations of 360 and 3600 ppm caused a total destruction of the cells. At 36 ppm the cells remained alive. This concentration produced a significant rise of the SCE rate from 12.53 to 16. Tubes with residues of 200 to 600 ppm ethylene oxide brought about a consistent rise of the SCE ratio in the sense of a dose-response relationship. Ethylene oxide has besides its toxic reaction a mutagenic effect upon human fibroblasts. Many other chemical substances have mutagenic potencies also. For safety reasons ethylene oxide sterilized equipment should be aerated before its use as completely as possible.

[Absorption and desorption of ethylene-oxide in anaesthesia-supplies (author's transl)]. / Absorption und Desorption von Athylenoxid in anaesthesie-Zubehör.

After ethylene oxide sterilization unwanted side effects are possible if the sterilized materials are not aerated sufficiently. The desorption of ethylene oxide depends upon many factors. Some of these are the composition of the sterilized materials and the various aeration provisions. It is nearly impossible to make general aeration recommendations because almost each item has different characteristics in regard to the absorption and desorption of ethylene oxide. We investigated the ethylene oxide residues in endotracheal tubes, nasal and oropharyngeal airways of various manufacturers as well as breathing tubes and bags of the Rüsch Company. For sterilization we used two DMB STERIVIT high pressure sterilizers, one Webeco ATOMAT 18, one Webeco ATOMAT 170 and one STERI-VAC 400 B Sterilizer of the 3 M Deutschland Company which operated under a low pressure system. For determination of the residues wer performed a total of about 1000 gaschromatographic analyses. The materials were aerated for 7-10 days at room temperature of 22 to 25 degrees C. IOn addition we perfused children PVC endotracheal tubes with 3 liter/min N2O/O2. By this considerable higher amounts of ethylene oxide were released than in quiet room air. The following recommendations can be made: Portex Blue Line and Rüsch Rüschelit acult tubes should aerate for 10 days. For Portex Blue Line children tubes a shorter time will be sufficient. Portex "green"PVC and Rüsch red rubber tubes retained less ethylene oxide than Blue Line and Rüschelit tubes. Portex oral airways must be vented for 10 days. Rüsch breathing tubes and bags can be used after 48 hours. The recommended aeration time must be observed precisely. Modern heated aerators with continuous air exchange accelerate the degassing process considerably.

[The endotracheal intubation of rabbits with xylazine and ketamine (author's transl)]. / Die endotracheale Intubation von Kaninchen unter Xylazin und Ketamin.

The intubation of rabbits is difficult. This is due to the anatomical structure of these animals. We intubated 40 New Zealand rabbits with a body weight of 2.0 to 2.8 kg with endotracheal tubes of an inner diameter 3.0 to 3.5 mm. Premedicating agents were Xylazine 1 ml/kg and Atropine 0.25 mg/kg. For induction of anaesthesia we used Ketamine in a dilution of 5 mg/ml and in dosages of 2.5 to 5.0 mg/kg. The intubation was performed with the aid of a Foregger childrens laryngoscope and a Wis-Hippel blade. For maintenance of anaesthesia we used a mixture of nitrous oxide/oxygen administered through a Kuhn system. In addition to this inhalation anesthetic Ketamine 1 to 2 mg was injected intermittently i.v. The recovery time with this method was extremely short in comparison to the use of intramuscular injections of Ketamine as monoanesthetic.

[The problems of intubation lesions with long-term artificial respiration (author's transl)]. / Problematik von Intubations-schäden bei Langzeitbeatmung

Necroses of the tracheal wall with esophagotracheal and mediastinal fistulas are a serious complication of modern long-term artificial respiration through inflatable tubes. Different types of cuff, a number of control and monitoring mechanisms against over-pressure in the cuff are described. The intermittent blocking and unblocking method seems to be of importance. A simple and reliable method of intermittent occlusion of the trachea is obtained with the new Abouav and Finley parachute cuff with pressures which never exceed the artificial respiratory pressure of the ventilation system.

[Damage of teeth by oral airways]. / Zahnbeschädigungen durch Guedel-Tuben

Oral Guedel airways do not necessarily protect the patient's teeth during inhalation anesthesia. This is contrary to the general opinion. Because of the anatomical structure of the human teeth and the dynamic forces on teeth occlusion during postanesthetic excitation the applied chewing-pressure is concentrated by a Guedel airway at a few front teeth only. Under this abnormally forceful, localized pressure especially capped teeth and teeth in gums with paradentosis may easily break. Therefore, the use of nasal airways should be preferred in these cases.

[Ulstrasonic monitoring for early diagnosis of air embolism during neurosurgical procedures (author's transl)]. / Ultraschall-Uberwachungsverfahren zur Frühdiagnose von Luftembolien bei neurochirurgischen Eingriffen

The sitting position of the patient offers many advantages to the neurosurgeon for operations at the posterior fossa, the upper cervical region, the Gasserian ganglion and the retroganglionic trigeminal root. Air embolism is however one of the greatest dangers during operations in this position. Air emboli occur more frequently than it is generally recognized. Most monitoring systems indicate the entrance of air at a late stage only. But early diagnosis and immediate therapy are of utmost importance. The use of an ultrasonic monitoring device for early diagnosis and the preoperative insertion of a right artrial catheter for immediate aspiration of the air are recommended.

[The effect of ethylene oxide and chemical disinfectant residues upon the larynx- and tracheal mucosa of rabbits (author's transl)]. / Die Wirkung von Athylenoxid- und chemischen Desinfektions-mittel-Rückständen auf die Larynx- und trachealschleimhaut von Kaninchen.

Residues of ethylene oxide and chemical disinfectants in anesthesia supplies can cause side effects in patients. For this reason we intubated 37 New Zealand rabbits with PVC endotracheal tubes of 3.0-3.5 mm inner diameter. The tubes were sterilized with ethylene oxide and aerated for 24 or 48 h in room air. At this time they still held 600 resp. 80 ppm ethylene oxide as we had determined by gaschromatography. For comparison tubes were soaked in 2% activated Cidex or 10% Gigasept and watered for 1 h in sterile water. 5 not intubated animals served as controls. All rabbits were sacrificed after 48 h and larynx and trachea examined microscopically for histological changes. In all intubated animals we found hyperemia, edema formation and cellular infiltration. In addition there were epithelial erosions in about 60% and 4 uclers. The findings were considerably more pronounced in animals which had been intubated with tubes containing 600 ppm ethylene oxide. Almost all tubes cause mechanical irritation of the respiratory tract. Additional chemical trauma is not to be expected, however, if they are watered adequately after treatment with disinfecting solutions resp. aerated sufficiently after ethylene oxide sterilization.