Research gaps and future needs for allergen prediction in food safety

The allergenicity and protein risk assessments in food safety are facing new challenges. Demands for healthier and more sustainable food systems have led to significant advances in biotechnology, the development of more complex foods, and the search for alternative protein sources. All this has increased the pressure on the safety assessment prediction approaches anchored into requirements defined in the late 90's. In 2022, the EFSA's Panel on Genetically Modified Organisms published a scientific opinion focusing on the developments needed for allergenicity and protein safety assessments of new products derived from biotechnology. Here, we further elaborate on the main elements described in this scientific opinion and prioritize those development needs requiring critical attention. The starting point of any new recommendation would require a focus on clinical relevance and the development of a fit-for-purpose database targeted for specific risk assessment goals. Furthermore, it is imperative to review and clarify the main purpose of the allergenicity risk assessment. An internationally agreed consensus on the overall purpose of allergenicity risk assessment will accelerate the development of fit-for-purpose methodologies, where the role of exposure should be better clarified. Considering the experience gained over the last 25 years and recent scientific developments in the fields of biotechnology, allergy, and risk assessment, it is time to revise and improve the allergenicity safety assessment to ensure the reliability of allergenicity assessments for food of the future.

Comparison of Parametric and Non-parametric EEG Feature Extraction Methods in Detection of Pediatric Migraine without Aura

BACKGROUND

Migraine headache without aura is the most common type of migraine especially among pediatric patients. It has always been a great challenge of migraine diagnosis using quantitative electroencephalography measurements through feature classification. It has been proven that different feature extraction and classification methods vary in terms of performance regarding detection and diagnostic accuracy. Previous work on the subject was controversial, hence a comparison of these methods seems necessary.

OBJECTIVE

The aim of this research is to compare two parametric and non-parametric feature extraction methods and also two classification methods in order to obtain optimal combinations of diagnostic accuracy.

MATERIALS AND METHODS

Having recorded background EEG from 24 pediatric migraineurs and 19 control subjects, data was processed by Welch's and Yule-Walker's methods. Features were selected using genetic algorithm, and then given to a support vector machine and the linear discriminant analysis for the classification. Accuracy was calculated for all combinations having the dominant frequency and the correlated absolute power of each EEG wave band (theta, alpha, and beta) and for all wave bands combined.

RESULTS

The highest migraine detection accuracy of 93% was obtained utilizing Welch's method for EEG feature extraction alongside support vector machine for a classifier. Besides, Yule-Walker autoregressive method showed better performance than Welch's, when only power bands (and not the dominant frequency) were used as classification input.

CONCLUSION

The superiority of Welch's method over Yule-Walker's and the support vector machine over linear discriminant analysis can be great help for further researches on computer aided EEG-based diagnosis of migraine.

Determination of helix orientations in a flexible DNA by multi-frequency EPR spectroscopy

Distance measurements are performed between a pair of spin labels attached to nucleic acids using Pulsed Electron-Electron Double Resonance (PELDOR, also called DEER) spectroscopy which is a complementary tool to other structure determination methods in structural biology. The rigid spin label Ç, when incorporated pairwise into two helical parts of a nucleic acid molecule, allows the determination of both the mutual orientation and the distance between those labels, since Ç moves rigidly with the helix to which it is attached. We have developed a two-step protocol to investigate the conformational flexibility of flexible nucleic acid molecules by multi-frequency PELDOR. In the first step, a library with a broad collection of conformers, which are in agreement with topological constraints, NMR restraints and distances derived from PELDOR, was created. In the second step, a weighted structural ensemble of these conformers was chosen, such that it fits the multi-frequency PELDOR time traces of all doubly Ç-labelled samples simultaneously. This ensemble reflects the global structure and the conformational flexibility of the two-way DNA junction. We demonstrate this approach on a flexible bent DNA molecule, consisting of two short helical parts with a five adenine bulge at the center. The kink and twist motions between both helical parts were quantitatively determined and showed high flexibility, in agreement with a Förster Resonance Energy Transfer (FRET) study on a similar bent DNA motif. The approach presented here should be useful to describe the relative orientation of helical motifs and the conformational flexibility of nucleic acid structures, both alone and in complexes with proteins and other molecules.

Induction of heart failure: haemodynamic comparison of three different canine models

We compared three methods: arteriovenous anastomosis, doxorubicin administration, and combination of anastomosis and doxorubicin, with the intention of designing a simple, stable model of chronic heart failure. Twelve dogs were divided into three groups of four. One group received carotid-jugular anastomosis (Ana series), another group received anastomosis and doxorubicin injection (A/D series), and the last group received only doxorubicin (Dox series). Animals were followed for eight weeks. Fifteen different haemodynamic parameters were tracked and compared to baseline values. After eight weeks, diastolic pressure in the right atrium increased from 3.8±2.0 mmHg at baseline to 5.3±5.9 mmHg in the Ana series, to 6.3±3.3 mmHg in the Dox series and to 8.0±2.0 mmHg in the A/D series ( P<0.05 A/D vs. baseline). Systolic pulmonary wedge pressure increased from 11.6±2.0 mmHg at baseline to 15.5±3.4 mmHg in the Ana series, 14.0±3.7 mmHg in the Dox series and 17.3±4.2 mmHg in the A/D series ( P = NS vs. baseline). Left ventricular ejection fraction decreased from 53.9±10% at baseline to 36.1±5.6% in the Ana series ( P<0.05 vs. baseline), 31.5±5.4% in the Dox series ( P<0.05 vs. baseline) and 25.8±5.8% in the A/D series ( P<0.001 vs. baseline, P<0.05 vs. Ana series and Dox series). In conclusion, eight weeks are not enough to produce stable heart failure using arteriovenous anastomosis alone. Doxorubicin administration alone produces a left ventricular failure. However, a combination of both of these interventions provides a more stable model of right-and left-sided heart failure

Synthesis and Pharmacological Evaluation of New Chemical Entities from Ibuprofen as Novel Analgesic Candidates

Non-steroidal anti-inflammatory drugs (NSAIDs) are the first choice of drugs that are normally used for the treatment of pain and inflammation. Ibuprofen (I) and its analogues as the most widely used NSAIDs have been synthesized in recent years. In an effort to establish new candidates with improved analgesic properties, derivatives (II-VII) with substituted aromatic as well as aliphatic moieties were synthesized in this experiment and evaluated in formalin test with rats. The results were compared to ibuprofen and control groups. Findings indicated that derivatives with new alkylphenyl rings (VI and VII) had some similar or more analgesic activities relative to the control and ibuprofen groups, respectively; which could be justified as to more alkyl and phenyl groups instead of p-isobutylphenyl moiety in I.

Adhesion to Er:YAG laser and bur prepared root and crown dentine

BACKGROUND

The purpose of this study was to evaluate the bond strengths between dentine and resin composite obtained after Er:YAG laser treatment of crown or root dentine used together with self-etch and total-etch adhesive systems.

METHODS

One etch-and-rinse adhesive (Single Bond, 3M, USA) and one self-etch system (Clearfil SE Bond, Kuraray, Japan) were applied to root and crown dentine prepared with a regular bur in a turbine or with an Er:YAG laser. The shear bond strength was determined after thermocycling and statistically analysed using independent t-tests.

RESULTS

Crown sites bonded using Clearfil SE Bond and Single Bond adhesives yielded bond strengths similar to that of root dentine sites (p > 0.05). Clearfil SE Bond was stronger in both the lased and non-lased groups (p < 0.05). The lowest bond strength was obtained when Single Bond without acid etching was used on Er:YAG ablated dentine. When total-etch adhesive was used, there were significant differences (p < 0.05) between the laser-ablated and laser-ablated/acid-etched and bur-cut/acid-etched groups.

CONCLUSIONS

Er:YAG laser irradiation of root and crown dentine conducted prior to the adhesive protocol adversely affected adhesion and decreased bond strength compared with traditional preparation.

Direct halogenation of organic compounds with halides using oxone in water — A green protocol

Direct bromination and iodination of various aromatic compounds with NaBr and NaI using oxone (2KHSO5·KHSO4·K2SO4) in water was accomplished successfully in high-to-excellent yields. The main benefit of this protocol is the performance of the reactions in water in the presence of a harmless oxidant without the use of any organic co-solvents. Using NaBr and NaI as the safe sources of halogens is another advantage of the protocol. This method is easily applicable to the large-scale operations. We have also applied this method successfully for the iodocyclization of an unsaturated alcohol and an unsaturated carboxylic acid.

Can sperm protamine deficiency induce sperm premature chromosomal condensation?

Sperm premature chromatin condensation (PCC) has been considered as the second cause of failed fertilization post-intracytoplasmic sperm injection (post-ICSI). Cytoplasmic factors, including oocyte cytoplasmic immaturity have been suggested to induce PCC sperm. However, recent studies suggest that sperm chromatin anomaly might also lead to PCC sperm. During this study, human sperm from infertile patients with protamine deficiency or with adequate amount of protamine assessed by chromomycin A3 were injected into metaphase II mouse oocyte, treated with colcemid. Chromatin analysis was carried out on the injected oocyte. The results of this study show that contrary to the percentage of intact sperm, percentage of PCC sperm was significantly higher in oocytes injected with protamine deficient sperm (36.43 +/- 4.46) compared to oocytes injected with sperm with an adequate amount of protamine (11.99 +/- 3.54, P < 0.001). A significant correlation was also observed between percentage of PCC sperm and protamine deficiency (r = 0.46, P = 0.004). Therefore, it can be suggested that oocytes injected with protamine deficient sperm have a higher chance of forming PCC sperm and may result in failed fertilization post-ICSI.

Implication of therapeutic cloning for organ transplantation

Replacement of damaged myocardium with electrically functional, contracting syncytium with a balanced blood supply remains a key goal for the treatment of hearts damaged by coronary heart disease or other disorders. Stem cell therapy offers a potential solution. This paper describes the value of in vitro stem cell research to unravel the roles of key regulatory molecules in embryogenesis of myocardium and blood vessels. Studies have shown that functioning myocytes can be derived from stem cells in vitro and engrafted into infarcted areas of heart where they develop into functional adult like cardiomyocytes with action potentials and capacity for beta adrenergic and muscarinic regulation. Further studies have identified specific roles for platelet endothelial cell adhesion molecule (PECAM), vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) in the sequential differentiation of blood vessels and capillaries.

Combined pars plana lensectomy-vitrectomy with open-loop flexible anterior chamber intraocular lens (AC IOL) implantation for subluxated lenses

OBJECTIVES

To review our experience with combined pars plana lensectomy-vitrectomy and open-loop flexible anterior chamber intraocular lens (AC IOL) implantation for managing subluxated crystalline lenses.

METHODS

Retrospective review of 36 consecutive eyes (28 patients), all of which had subluxated crystalline lenses, managed by pars plana lensectomy-vitrectomy with insertion of an open-loop flexible AC IOL. The study was performed at the Medical College of Wisconsin, Milwaukee, over an 8-year period.

RESULTS

An average preoperative visual acuity of 20/163 (range, 20/25 to hand motions) improved to 20/36 (range, 20/20 to 4/200) with surgery after a mean follow-up of 14 months (range, 1 to 59 months) (P < .001, Student's paired t test). Final visual acuity of 20/40 or better was achieved in 75% of eyes (27/36). Complications included cystoid macular edema (8% [3/36]), pupillary block (6% [2/36]), retinal detachment (3% [1/36]), hyphema (3% [1/36]), wound leak (3% [1/36]), and transient vitreous hemorrhage (3% [1/36]). No persistent ocular hypertension was seen, nor did angle abnormalities or corneal decompensation develop.

CONCLUSIONS

Pars plana lensectomy-vitrectomy with AC IOL implantation appears to be an excellent technique for managing subluxated crystalline lenses. It is associated with a significant improvement in visual acuity (P < .001) and avoids many of the complications seen with extraction of a subluxated lens through a limbal wound. Additionally, use of an AC IOL offers a simplified alternative to placement of a ciliary sulcus sutured posterior chamber intraocular lens (PC IOL).

Affinity isolation and characterization of cytochrome P450 102 (BM-3) from barbiturate-induced Bacillus megaterium

Cytochrome P450 102 (BM-3) is a catalytically self-sufficient enzyme from Bacillus megaterium that is presently accepted as an important model of the mammalian microsomal P450 monooxygenase system. We have developed a novel affinity approach to purify P450 102 in a single chromatographic step and have studied the spectroscopic, catalytic, nucleotide binding, and crystallization properties of the highly purified enzyme. B. megaterium ATCC 14581 was grown to high cell density, and P450 102 was purified rapidly and in high yield by chromatography on adenosine-2',5'-diphosphate agarose from crude cell-free extract. The cytochrome bound to the column with remarkable avidity, in contrast to the significantly weaker binding observed for NADPH-cytochrome P450 reductase. Chromatographic behavior also showed that the cytochrome bound NADP(+)-type nucleotides more tightly than any other cellular polypeptide. The purified protein was electrophoretically homogeneous and had essentially theoretical contents of FAD, FMN, and heme. Optical spectra showed the expected heme and flavin absorption bands, and three previously undescribed charge-transfer-type absorptions were characterized. Molar extinction coefficients in the oxidized, fully reduced, and ferrous carbonyl states have been determined; notable is the large soret extinction in the ferrous carbonyl state (epsilon 449 nm = 143,500 M-1 cm-1). Final preparations were active in the oxidation of a wide variety of substrates. Of the C14 alkyl compounds studied, tetradecyltrimethylammonium bromide showed the highest substrate-dependent oxidation of NADPH, followed by myristate and myristyl alcohol; however, myristate exhibited the lowest Km value. Activities were tightly coupled to NADPH oxidation (> 97%). Phenobarbital, benzphetamine, cocaine, cyclohexane, methanol, ethanol, retinoic acid, benzoate, heptaflourobutyrate, and 7-ethoxycoumarin were not substrates. NADP+ titrations showed, as expected, that the coenzyme was bound very tightly, with an average Kd of 580 nM. Our preparations of P450 102 are of sufficient purity and stability that crystals of the native holoenzyme have been grown.

Apical correlative effects in leaf epinasty of tomato

The influence of the stem apex on leaf curvature was investigated using debudded tomato (Lycopersicon esculentum Mill. cv Anahu) plants and petiole explants, consisting of a section of petiole attached to a section of stem.Decapitation of the main shoot of tomato plants induced hyponasty of petioles in young leaves. Application of auxin in place of the removed apex or fumigation of intact tomato plants with ethylene produced epinastic curvature at the base of the petiole. Simultaneous carbon dioxide treatments prevented the development of petiolar epinasty due to auxin and ethylene treatments. Application of ethylene gas to the decapitated shoot or injection into the stem, induced petiolar epinasty. In a saturating level of ethylene gas, tomato petioles did not respond to indole-3-acetic acid applied to the cut apex. Auxin-induced ethylene production in petiole explants preceded the development of epinasty. Application of indoleacetic acid in lanolin to the entire lower side of the petioles of leaves in situ produced petiole epinasty. Petiolar epinasty due to apically applied indoleacetic acid resulted from differential cell elongation.The auxins indole-3-acetic acid, 2,4-dichlorophenoxyacetic acid, and naphthalene-1-acetic acid induced epinasty when applied apically to decapitated tomato plants, while gibberellic acid, kinetin, abscisic acid, and auxin or gibberellin antagonists had no effect. When such compounds were applied to petiole explants, only indole-3-acetic acid and kinetin caused an increase in ethylene production and the effect of kinetin was relatively weak.Application of 2,3,5-triiodobenzoic acid around the stem did not change the effect on petiolar epinasty of auxin applied to the decapitated shoot or around the stem. Radioautography showed that the label from (14)C-indoleacetic acid applied apically entered the petiole and midrib tissue; however, extraction showed that only a fraction of the label in these tissues was in the form of indoleacetic acid.Removal of leaflets from leaves induced hyponasty in the midrib region, and application of auxin to the leaflet stubs produced midrib epinasty; carbon dioxide did not block the action of auxin in this type of epinasty. Removal of leaflets from leaves did not alter the effect of apically applied auxin on petiolar epinasty.The data are consistent with the hypothesis that the oblique orientation of leaves in tomato plants is influenced by two epinastic responses. Petiolar epinasty is controlled by the apical region on the stem and is due to the action of auxin-induced ethylene; and midrib epinasty is due to an action of auxin other than through ethylene.