Knowledge and awareness of ocular allergy among undergraduate students at a public university in Riyadh, Saudi Arabia.

Background: Ocular allergy (OA) is one of the most common disorders worldwide, affecting millions of individuals of all ages. Public education about the disease is critical for lowering the prevalence of OAs. The present study aims to evaluate the knowledge and awareness level of OA among undergraduate students at Imam Mohammed Ibn Saud Islamic University in Riyadh, Saudi Arabia.

Humoral Response to Hepatitis B and COVID-19 Vaccine among Maintenance Hemodialysis Patients.

Maintenance hemodialysis (MHD) patients have impaired immunological responses to pathogens and vaccines. In this study, we compared the humoral response to HBV and COVID-19 vaccines in a cohort of MHD patients. Demographic and clinical characteristics of vaccine responders and non-responders were also compared, and the association between the humoral responses to both vaccines was evaluated.

The effect of perceived insufficient milk on transition to supplementary food and factors affecting it during the first six months postpartum in Turkey: A cross-sectional study.

The researchers' aims were to determine the effect of perceived insufficient milk supply on the transition to supplementary food and the factors affecting it. This is a cross-sectional design study, we were conducted between April and August 2019 and included 335 mothers and their babies in a baby-friendly hospital in Turkey. It was shown that mothers with perceived insufficient milk switched to supplementary food 6.

A quantitative method for the detection and validation of catalase activity at physiological concentration in human serum, plasma and erythrocytes.

A novel method has been proposed to develop a simple, rapid, sensitive and affordable chromogenic attempt for the quantification of catalase (CAT) activity in blood samples. The method is based on the oxidation of pyrocatechol (PC) to give quinone form which by oxidative coupling with aminyl radical of 4-aminoantipyrine (4-AAP) resulting from HO/CAT to produce a pink colored quinone-imine product with λ = 530 nm in a 100 mmol/L of tris buffer of pH 9.8 at room temperature (30 °C).

Ninhydrin-sodium molybdate chromogenic analytical probe for the assay of amino acids and proteins.

A sensitive method has been proposed for the quantification of amino acids and proteins using ninhydrin and sodium molybdate as chromogenic substrates in citrate buffer of pH5.6. A weak molybdate-hydrindantin complex plays the role in the formation of Ruhemann's purple.

A spectrophotometric assay method for vanadium in biological and environmental samples using 2,4-dinitrophenylhydrazine with imipramine hydrochloride.

A simple, rapid, and sensitive method involving the interaction of 2,4-dinitrophenylhydrazine with imipramine hydrochloride in presence of vanadium (V) in sulfuric acid medium has been proposed for the determination of vanadium. The purple-colored product developed showed an absorption maximum at 560 nm and was stable for 24 h. The working curve was linear over the concentration range of 0.

A simple and sensitive spectrophotometric method for the determination of trace amounts of nitrite in environmental and biological samples using 4-amino-5-hydroxynaphthalene-2,7-disulphonic acid monosodium salt.

A very simple, sensitive, fairly selective and rapid spectrophotometric method for the determination of trace amounts of nitrite has been described. This method is based on the diazotized intramolecular coupling of electrophilic diazonium cation with the phenolic group of 4-amino-5-hydroxynaphthalene-2,7-disulphonic acid monosodium salt (AHNDMS) in a phosphate buffer solution of pH 7.5.

Development of a selective and sensitive spectrophotometric method for the trace determination of thallium(III) using 3-methyl-2-benzothiazolinone hydrazone hydrochloride and N-(1-naphthyl)-ethylenediamine dihydrochloride.

A simple, selective, sensitive, and rapid spectrophotometric method has been developed for the determination of thallium(III) using 3-methyl-2-benzothiazolinone hydrazone hydrochloride and N-(1-naphthyl)-ethylenediamine dihydrochloride. The obtained product had an absorption maximum of 590 nm. Beer's law was valid over the concentration range of 0.

ARS Component B: structural characterization, tissue expression and regulation of the gene and protein (SLURP-1) associated with Mal de Meleda.

The ARS Component B gene (EMBL ID: HSARS81S, AC: X99977) encodes a 9 kD non-glycosylated polypeptide (also known as SLURP-1, SwissProt/TrEMBL: P55000), a soluble member of the human Ly6/uPAR superfamily. ARS Component B gene mutations have been implicated in Mal de Meleda. In this study we show by immunohistochemistry that SLURP-1 (secreted Ly-6/uPAR related protein, the protein product of the ARS Component B gene) is localized to human skin, exocervix, gums, stomach and esophagus.

Follicle stimulating hormone and its receptor: future perspectives.

In this report, we review our present effort in the field of molecular reproductive endocrinology: to identify a small molecular weight follicle stimulating hormone (FSH) agonistic molecule. To achieve this goal we require a number of molecular tools. We have cloned and expressed the human gonadotrophin, FSH and the human FSH receptor and developed a reliable high throughput assay.

Characterization of the major histocompatibility complex class II binding site on LAG-3 protein.

The lymphocyte activation gene-3 (LAG-3), selectively transcribed in human activated T and NK cells, encodes a ligand for major histocompatibility complex (MHC) class II molecules. Like CD4, LAG-3 ectodomain is composed of four Ig-like domains (D1-D4). Nothing is known about the LAG-3 regions or residues required to form a stable MHC class II binding site.

Advances in the molecular understanding of gonadotropins-receptors interactions.

The extracellular domain (ECD) of gonadotropin receptors belong to the leucine-rich repeat (LRR) protein superfamily and their transmembrane domain (TMD) is characteristic of the seven alpha-helices G-protein-coupled receptors (GPCR). The availability of the X-ray structures of porcine ribonuclease inhibitor (RI), a LRR protein, and bacteriorhodopsin (bR) allows the construction of 3D models of the ECD and the TMD of gonadotropin receptors, respectively. The predicted models are to a large extent consistent with currently available biochemical and mutational data.

Structural predictions for the ligand-binding region of glycoprotein hormone receptors and the nature of hormone-receptor interactions.

Background: Glycoprotein hormones influence the development and function of the ovary, testis and thyroid by binding to specific high-affinity receptors. The extracellular domains of these receptors are members of the leucine-rich repeat (LRR) protein superfamily and are responsible for the high-affinity binding. The crystal structure of a glycoprotein hormone, namely human choriogonadotropin (hCG), is known, but neither the receptor structure, mode of hormone binding, nor mechanism for activation, have been established.

Structure-lipophilicity relationships of peptides and peptidomimetics.

Understanding the physicochemical and structural properties of peptides are important prerequisites for the rational design of bioactive peptides and peptidomimetics. The present contribution reviews methods used for the assessment and prediction of lipophilicity (or hydrophobicity) and their correlation with structural elements of peptides and closely related peptidomimetics.

Lipophilicity of amino acids.

The lipophilicity (or hydrophobicity) of amino acids is an important property relevant for protein folding and therefore of great interest in protein engineering. For peptides or peptidomimetics of potential therapeutic interest, lipophilicity is related to absorption and distribution, and thus indirectly relates to their bioactivity. A rationalization of peptide lipophilicity requires basic knowledge of the lipophilicity of the constituting amino acids.

Solvent-dependent conformation and hydrogen-bonding capacity of cyclosporin A: evidence from partition coefficients and molecular dynamics simulations.

The partition coefficient of cyclosporin A (CsA) was measured in octanol/water and heptane/water by centrifugal partition chromatography. By comparison with results from model compounds, it was deduced that the hydrogen-bonding capacity of CsA changed dramatically from an apolar solvent (where it is internally H-bonded) to polar solvents (where it exposes its H-bonding groups to the solvent). Molecular dynamics simulations in water and CCl4 support the suggestion that CsA undergoes a solvent-dependent conformational changes and that the interconversion process is slow on the molecular dynamics time scale.

Effects of solvation on the ionization and conformation of raclopride and other antidopaminergic 6-methoxysalicylamides: insight into the pharmacophore.

Previous work has shown that raclopride in water at neutral pH exists in a zwitterionic form, suggesting a stereoelectronic structure largely different from that of other benzamides. In the present study, the acid-base behavior of other 6-methoxysalicylamides is shown to be comparable to that of raclopride. An extensive investigation by high-temperature molecular dynamics gave insight into the conformational behavior of neutral and zwitterionic raclopride in vacuum and in water.

Quantitative structure-metabolism relationship analyses of MAO-mediated toxication of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and analogues.

The 1-octanol/water partition coefficients of a number of toxic and nontoxic analogues of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) were determined using centrifugal partition chromatography (CPC), a novel and effective technique for measuring lipophilicity, and found to be highly correlated with values calculated by a fragmental method. Some conformational properties of these compounds were also assessed by molecular mechanics calculations and 1H-NMR spectroscopy. A quantitative structure-metabolism relationship (QSMR) study of MPTP and analogues based on literature data was undertaken in order to determine the key features eliciting MAO-A and MAO-B reactivity and selectivity and influencing toxication.

Percutaneous penetration of drugs: a quantitative structure-permeability relationship study.

Human skin permeation data taken from the literature were analyzed for quantitative relationships with physicochemical properties and structural descriptors. No correlations exist with molecular weights and solvent-accessible surface areas. In most cases, skin permeation was inversely correlated with the parameter delta log Poct-hep (i.

Partitioning of solutes in different solvent systems: the contribution of hydrogen-bonding capacity and polarity.

Published partition coefficient values of 121 solutes in five solvent systems (1-octanol-water, n-heptane-water, chloroform-water, diethyl ether-water, and n-butyl acetate-water) were correlated with solute properties, namely intrinsic molecular volume (indicator of cavity formation) and the solvatochromic parameters pi* (dipolarity/polarizability), beta (H-bond acceptor basicity), and alpha (H-bond donor acidity). While the cavity term and the H-bond accepting capacity played a comparable role in all solvent systems, the H-bond donor acidity was significant only in the alkane-water and chloroform-water systems. Comparison of the regression coefficients of pi*, beta, and alpha demonstrated the important role that water content at saturation in the organic solvents plays in the partitioning of solutes.

Morphine 6-glucuronide and morphine 3-glucuronide as molecular chameleons with unexpected lipophilicity.

Morphine 6-glucuronide, but not morphine 3-glucuronide, is a highly potent opiate receptor agonist. In fact, there is converging evidence that much of the analgesic effect occurring after morphine treatment in humans is due to this metabolite rather than to the parent drug. Yet glucuronides as a rule are considered as highly polar metabolites unable to cross the blood-brain barrier and rapidly excreted by the urinary and/or biliary routes.

Determination of lipophilicity and hydrogen-bond donor acidity of bioactive sulphonyl-containing compounds by reversed-phase HPLC and centrifugal partition chromatography and their application to structure-activity relations.

The lipophilic character of two large series of substituted benzenesulphonamides (BzSA) and 4-aminodiphenylsulphones (4-ADS) has been assessed by two chromatographic methods, i.e. reversed-phase HPLC using a relatively novel octadecylpolyvinyl packing and centrifugal counter-current chromatography (CPC).

Toxication of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) and analogs by monoamine oxidase. A structure-reactivity relationship study.

MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) elicits motor deficits similar to those observed in Parkinson's disease. Before exerting its neurotoxic action, MPTP must be activated by brain monoamine oxidase (MAO) to the neurotoxic metabolite MPP+ (1-methyl-4-phenylpyridinium). MPTP derivatives differ in their reactivity as MAO substrates and in their neurotoxicity.