Comparison of 1-year results of single transforaminal epidural steroid injection among patients with different spinal pathologies-related radicular pain.

AIMS: This study aims to investigate the effectiveness of transforaminal epidural steroid injection (TFESI) in patients with lumbar radicular pain or radiculopathy caused by different spinal pathologies. METHODS: One hundred and seventy seven patients who underwent single transforaminal epidural steroid injection were included in the study group and divided into 3 subgroups (central spinal stenosis + lateral recess stenosis, foraminal stenosis, lumbar disc herniation) according to existing spinal pathology. Patients' visuel analogue scale (VAS) measures and Oswestry Disability Index (ODI) scores were recorded and the patients who give favourable response to treatment were called respondents and who were not called as non-respondents. Subgroups were compared statistically at the end of 12 months. RESULTS: Sixty patients (33.9%) were considered as respondents and 117 patients (66.1%) were non-respondents in the entire study group. Patients with foraminal stenosis included the vast majority of the respondents and showed better results of pain relief as opposed to patients of other groups at the end of 12 months (P < 0.001). CONCLUSION: TFESI was an effective treatment modality for pain relief and functional improvement in patients with foraminal stenosis. However, it could not produce the same results in patients with central spinal stenosis and lumbar disc herniations.

Spontaneous regression of lumbar disc herniations: A retrospective analysis of 5 patients.

The aim of this study is to describe patients who represent spontaneous regression of lumbar disc herniations (LDHs) subsequent to conservative treatments. In this retrospective study, medical records of 862 patients who had presented to our neurosurgery department with LDHs between May 2014 and May 2016 were studied. All of these patients had a history of low back pain and radiculopathy. Lumbar magnetic resonance imaging (MRI) scans were performed to diagnose them.LDHs were categorized into four subtypes including disc bulging, protrusion, extrusion, and sequestration. Five patients developed spontaneous regression of LDHs according to spinal MRI scans. All patients relieved radiculopathy symptoms in 2 to 4 weeks and low back pain symptoms in 3 to 8 weeks except one patient. In one patient hypoesthesia symptom, in one patient motor deficit, and in one patient low back painremained after the regression. The clinical and diagnostic imaging characteristics and outcomes of these five patients are described and the pertinent literature regarding spontaneous regression of LDHs is reviewed. Sequestrated disc herniations represent the main candidates for spontaneous regression according to our clinical research and the pertinent literature. Dehydration and inflammation-related resorption are the main mechanisms for this event. Conservative treatment modalities should not be underestimated for the treatment of such patients in the absence of definitive surgical indications.

Restoration of structural stability and ligand binding after removal of the conserved disulfide bond in tear lipocalin.

Disulfide bonds play diverse structural and functional roles in proteins. In tear lipocalin (TL), the conserved sole disulfide bond regulates stability and ligand binding. Probing protein structure often involves thiol selective labeling for which removal of the disulfide bonds may be necessary. Loss of the disulfide bond may destabilize the protein so strategies to retain the native state are needed. Several approaches were tested to regain the native conformational state in the disulfide-less protein. These included the addition of trimethylamine N-oxide (TMAO) and the substitution of the Cys residues of disulfide bond with residues that can either form a potential salt bridge or others that can create a hydrophobic interaction. TMAO stabilized the protein relaxed by removal of the disulfide bond. In the disulfide-less mutants of TL, 1.0M TMAO increased the free energy change (ΔG(0)) significantly from 2.1 to 3.8kcal/mol. Moderate recovery was observed for the ligand binding tested with NBD-cholesterol. Because the disulfide bond of TL is solvent exposed, the substitution of the disulfide bond with a potential salt bridge or hydrophobic interaction did not stabilize the protein. This approach should work for buried disulfide bonds. However, for proteins with solvent exposed disulfide bonds, the use of TMAO may be an excellent strategy to restore the native conformational states in disulfide-less analogs of the proteins.

A simple model-free method for direct assessment of fluorescent ligand binding by linear spectral summation.

Fluorescent tagged ligands are commonly used to determine binding to proteins. However, bound and free ligand concentrations are not directly determined. Instead the response in a fluorescent ligand titration experiment is considered to be proportional to the extent of binding and, therefore, the maximum value of binding is scaled to the total protein concentration. Here, a simple model-free method is presented to be performed in two steps. In the first step, normalized bound and free spectra of the ligand are determined. In the second step, these spectra are used to fit composite spectra as the sum of individual components or linear spectral summation. Using linear spectral summation, free and bound 1-Anilinonaphthalene-8-Sulfonic Acid (ANS) fluorescent ligand concentrations are directly calculated to determine ANS binding to tear lipocalin (TL), an archetypical ligand binding protein. Error analysis shows that the parameters that determine bound and free ligand concentrations were recovered with high certainty. The linear spectral summation method is feasible when fluorescence intensity is accompanied by a spectral shift upon protein binding. Computer simulations of the experiments of ANS binding to TL indicate that the method is feasible when the fluorescence spectral shift between bound and free forms of the ligand is just 8 nm. Ligands tagged with environmentally sensitive fluorescent dyes, e.g., dansyl chromophore, are particularly suitable for this method.

Fertility preservation options in women with endometriosis.

Endometriosis is a common, chronic condition in reproductive age women. Although some women may be asymptomatic, most women present with dysmenorrhea, dyspareunia, pelvic pain and/or infertility. Despite the fact that a causal relationship between endometriosis and infertility has not been clearly established, the fecundity rate of untreated women with endometriosis is lower than normal couples. However, suppressive medical therapy for endometriosis has not been shown to improve fecundity rates and may only result in a delay in the use of more effective treatments to achieve pregnancy. In the other hand, surgery for severe endometriosis can be useful to treat infertile women, but several studies reported a lower ovarian reserve after excision of ovarian endometriomas, due to incidental excision of normal ovarian tissue together with the endometrioma wall. Therefore, fertility preservation procedures should be considered to reproductive-age women at risk of impaired fertility related to endometriosis progression or endometriosis surgical treatment. The purpose of this document was to review the current literature regarding fertility preservation techniques for patients diagnosed with endometriosis.

Molecular docking of the pentapeptide derived from rice bran protein as anticancer agent inhibiting both receptor and non-receptor tyrosine kinases.

The cationic pentapeptide Glu-Gln-Arg-Pro-Arg (EQRPR) belongs to the family of anti-cancer peptides with significant anti-cancer activity. However, the mechanism by which the peptide performs this activity is unknown. In this study, we explored the pharmaceutical profile of Glu-Gln-Arg-Pro-Arg pentapeptide and revealed its anticancer properties by in silico docking studies. Moreover, the effect of EQRPR behavior of the DPPC membrane was investigated by means of Langmuir monolayer technique and the results were discussed in terms of mutual interactions. To evaluate the binding mechanisms, the pentapeptide and its various D-amino acid substituted analogs were docked to both epidermal growth factor receptor (EGFR) tyrosine kinase and proto-oncogene tyrosine-protein kinase, Fyn. Simultaneous binding of the pentapeptides to both EGFR and Fyn proteins, which are receptor- and non-receptor-kinases, respectively, suggest that these peptides can be an effective agent for cancer treatment. Moreover, to show the potential of the investigated pentapeptides to overcome the generated mutation-related drug resistance to EGFR targeted therapies, molecular docking investigations of EQRPR and all its D-analogs were performed against the prospective targets: Wild type EGFRWT and mutant EGFRT790M. Erlotinib and TAK-285 were used as reference molecules. The strong interaction of the peptide with EGFRWT (from -9.24 to -9.75 kcal/mol) and the secondary mutant EGFRT790M (from -9.28 to -9.64 kcal/mol) observed in most cancer recurrence cases indicates its good potential to overcome drug resistance in cancer therapy. In addition, the pharmacological properties of the investigated pentapeptides were revealed by in silico ADME (Absorption, Distribution, Metabolism, Excretion) and toxicity analysis.Communicated by Ramaswamy H. Sarma.

Cation-π interactions in lipocalins: structural and functional implications.

The cation-π interaction impacts protein folding, structural stability, specificity, and molecular recognition. Cation-π interactions have been overlooked in the lipocalin family. To fill this gap, these interactions were analyzed in the 113 crystal and solution structures from the lipocalin family. The cation-π interactions link previously identified structurally conserved regions and reveal new motifs, which are beyond the reach of a sequence alignment algorithm. Functional and structural significance of the interactions were tested experimentally in human tear lipocalin (TL). TL, a prominent and promiscuous lipocalin, has a key role in lipid binding at the ocular surface. Ligand binding modulation through the loop AB at the "open" end of the barrel has been erroneously attributed solely to electrostatic interactions. Data revealed that the interloop cation-π interaction in the pair Phe28-Lys108 contributes significantly to stabilize the holo-conformation of the loop AB. Numerous energetically significant and conserved cation-π interactions were uncovered in TL and throughout the lipocalin family. Cation-π interactions, such as the highly conserved Trp17-Arg118 pair in TL, were educed in low temperature experiments of mutants with Trp to Tyr substitutions.

The conserved disulfide bond of human tear lipocalin modulates conformation and lipid binding in a ligand selective manner.

The primary aim of this study is the elucidation of the mechanism of disulfide induced alteration of ligand binding in human tear lipocalin (TL). Disulfide bonds may act as dynamic scaffolds to regulate conformational changes that alter protein function including receptor-ligand interactions. A single disulfide bond, (Cys61-Cys153), exists in TL that is highly conserved in the lipocalin superfamily. Circular dichroism and fluorescence spectroscopies were applied to investigate the mechanism by which disulfide bond removal effects protein stability, dynamics and ligand binding properties. Although the secondary structure is not altered by disulfide elimination, TL shows decreased stability against urea denaturation. Free energy change (ΔG(0)) decreases from 4.9±0.2 to 2.1±0.3kcal/mol with removal of the disulfide bond. Furthermore, ligand binding properties of TL without the disulfide vary according to the type of ligand. The binding of a bulky ligand, NBD-cholesterol, has a decreased time constant (from 11.8±0.2 to 3.3s). In contrast, the NBD-labeled phospholipid shows a moderate decrease in the time constant for binding, from 33.2±0.2 to 22.2±0.4s. FRET experiments indicate that the hairpin CD is directly involved in modulation of both ligand binding and flexibility of TL. In TL complexed with palmitic acid (PA-TL), the distance between the residues 62 of strand D and 81 of loop EF is decreased by disulfide bond reduction. Consequently, removal of the disulfide bond boosts flexibility of the protein to reach a CD-EF loop distance (24.3Å, between residues 62 and 81), which is not accessible for the protein with an intact disulfide bond (26.2Å). The results suggest that enhanced flexibility of the protein promotes a faster accommodation of the ligand inside the cavity and an energetically favorable ligand-protein complex.

Ovarian cryopreservation.

Cryopreservation of ovarian tissue and future autotransplantation are new promising strategies for fertility preservation in various malignant and non-malignant diseases facing the risk of ovarian failure. Ovarian cortrical tissue pieces or intact whole ovary can be removed by laparoscopy without any significant delay in chemotherapy. Slow freezing and vitrification methods are developed to avoid damage to follicles. Ovarian tissue can be transplanted in an orthotopic or heterotopic location when the patient is cured from the disease. Autotransplantation can be performed if absence of malignant cells in the graft is confirmed. Although the procedures are still experimental, ovarian cryopreservation is the single option in prepubertal girls who have not sexual maturity. Earlier team approach of oncologists and reproductive endocrinologists may provide a more successful and professional way of fertility preservation.

Individual-oocyte transcriptomic analysis shows that genotoxic chemotherapy depletes human primordial follicle reserve in vivo by triggering proapoptotic pathways without growth activation.

Gonadotoxic chemotherapeutics, such as cyclophosphamide, can cause early menopause and infertility in women. Earlier histological studies showed ovarian reserve depletion via severe DNA damage and apoptosis, but others suggested activation of PI3K/PTEN/Akt pathway and follicle 'burn-out' as a cause. Using a human ovarian xenograft model, we performed single-cell RNA-sequencing on laser-captured individual primordial follicle oocytes 12 h after a single cyclophosphamide injection to determine the mechanisms of acute follicle loss after gonadotoxic chemotherapy. RNA-sequencing showed 190 differentially expressed genes between the cyclophosphamide- and vehicle-exposed oocytes. Ingenuity Pathway Analysis predicted a significant decrease in the expression of anti-apoptotic pro-Akt PECAM1 (p = 2.13E-09), IKBKE (p = 0.0001), and ANGPT1 (p = 0.003), and reduced activation of PI3K/PTEN/Akt after cyclophosphamide. The qRT-PCR and immunostaining confirmed that in primordial follicle oocytes, cyclophosphamide did not change the expressions of Akt (p = 0.9), rpS6 (p = 0.3), Foxo3a (p = 0.12) and anti-apoptotic Bcl2 (p = 0.17), nor affect their phosphorylation status. There was significantly increased DNA damage by γH2AX (p = 0.0002) and apoptosis by active-caspase-3 (p = 0.0001) staining in the primordial follicles and no change in the growing follicles 12 h after chemotherapy. These data support that the mechanism of acute follicle loss by cyclophosphamide is via apoptosis, rather than growth activation of primordial follicle oocytes in the human ovary.

Sodium fusidate prevents protein aggregation of silk fibroin and offers new perspectives for human lens material disaggregation.

Silk fibroin (SF) is a non-pathological amyloidogenic protein prone, in solution, to the formation of amyloid-like aggregated species, displaying similarities in fibrillation kinetics with pathological amyloids, as widely reported in the literature. We show here, on the basis of different biophysical approaches (turbidity, Congo Red assays, CD, DLS and fluorescence), that fusidic acid (FA), a well-known antibiotic, acts on SF as an anti-aggregating agent in a dose-dependent manner, being also able to revert SF aggregation. FA binds to SF inducing changes in the environment of SF aromatic residues. We further provide the proof of principle that FA, already approved as drug on humans and used in ophthalmic preparations, displays its anti-aggregation properties also on lens material derived from cataract surgery and is capable of reducing aggregation. Thus it is suggested that FA can be foreseen as a therapeutic treatment for cataract and other protein aggregation disorders.

Evaluation of anti-cancer and anti-covid-19 properties of cationic pentapeptide Glu-Gln-Arg-Pro-Arg, from rice bran protein and its d-isomer analogs through molecular docking simulations.

Bioactive peptides derived from food proteins are becoming increasingly popular due to the growing awareness of their health-promoting properties. The structure and mechanism of anti-cancer action of pentapeptide Glu-Gln-Arg-Pro-Arg (EQRPR) derived from a rice bran protein are not known. Theoretical and experimental methods were employed to fill this gap. The conformation analysis of the EQRPR pentapeptide was performed first and the obtained lowest energy conformer was optimized. The experimental structural data obtained by FTIR and CD spectroscopies agree well with the theoretical results. d-isomer introduced one-by-one to each position and all D-isomers of the peptide were also examined for its possible anti-proteolytic and activity enhancement properties. The molecular docking revealed avid binding of the pentapeptide to the integrins α5ß1 and αIIbß3, with Kd values of 90 nM and 180 nM, respectively. Moreover, the EQRPR and its D-isomers showed strong binding affinities to apo- and holo-forms of Mpro, spike glycoprotein, ACE2, and dACE2. The predicted results indicate that the pentapeptide may significantly inhibit SARS-CoV-2 infection. Thus, the peptide has the potential to be the leading molecule in the drug discovery process as having multifunctional with diverse biological activities.

pH-Dependent conformational changes in tear lipocalin by site-directed tryptophan fluorescence.

Tear lipocalin (TL), a major protein of human tears, binds a broad array of endogenous ligands. pH-dependent ligand binding in TL may have functional implications in tears. Previously, conformational selections of the AB and GH loops have been implicated in ligand binding by site-directed tryptophan fluorescence (SDTF). In this study, SDTF was applied to the AB and GH loops to investigate pH-driven conformational changes relevant to ligand binding. Both loops demonstrate significant but distinct conformational rearrangements over a wide pH range. In the low-pH transition, from 7.3 to 3.0, residues of the GH loop exhibit decreased solvent accessibilities. In acrylamide quenching experiments, the average quenching rate constant (k(q), accessibility parameter) of the residues in the GH loop is decreased approximately 38%, from 2.1 x 10(9) to 1.3 x 10(9) M(-1) s(-1). However, despite the significant changes in accessibilities for some residues in the AB loop, the average accessibility per residue remained unchanged (average k(q) = 1.2 M(-1) s(-1)). Accordingly, the low-pH transition induces conformational changes that reshuffle the accessibility profiles of the residues in the AB loop. A significant difference in the titration curves between the holo and apo forms of the W28 mutant suggests that the protonation states of the residues around position 28 modulate conformational switches of the AB loop relevant to ligand binding.

In vitro maturation improves oocyte or embryo cryopreservation outcome in breast cancer patients undergoing ovarian stimulation for fertility preservation.

This study tested in-vitro maturation (IVM) as a complementary strategy to improve the mature oocyte yield of breast cancer patients undergoing ovarian stimulation for fertility preservation. Secondary analysis of prospectively collected data is performed for 32 breast cancer patients undergoing oocyte or embryo cryopreservation before chemotherapy. Total number of oocytes and/or embryos cryopreserved following IVM is compared with the total number cryopreserved before IVM. Overall, 464 oocytes were retrieved, of which 274 were mature. Following IVM, the number of total mature oocytes increased to 399 (45% increase in mature oocyte yield, P<0.0001). Fertilization rate after IVM was statistically significantly higher than the fertilization of already mature oocytes at retrieval (86% versus 73%, respectively, P<0.05). The total number of oocytes and embryos frozen before IVM was 207 (45% of all oocytes retrieved). This number increased to 320 (69% of all oocytes retrieved) following IVM (P<0.0001). IVM is a useful strategy to improve the mature oocyte yield of fertility preservation cycles. Immature oocytes retrieved during oocyte/embryo cryopreservation cycles should not be discarded to improve the future potential of fertility.

ANS fluorescence: Potential to discriminate hydrophobic sites of proteins in solid states.

In the current study, ANS fluorescence was established as a powerful tool to study proteins in solid-state. Silk fibroin from Bombyx mori cocoons was used as a paradigm protein. ANS incorporated into the films of silk fibroin exhibits fluorescence with two-lifetime components that can be assigned to the patches and/or cavities with distinct hydrophobicities. Decay associated spectra (DAS) of ANS fluorescence from both sites could be fit to the single log-normal component indicating their homogeneity. ANS binding sites in the protein film are specific and could be saturated by ANS titration. ANS located in the binding site that exhibits the long-lifetime fluorescence is not accessible to the water molecules and its DAS stays homogeneously broadened upon hydration of the protein film. In contrast, ANS from the sites demonstrating the short-lifetime fluorescence is accessible to water molecules. In the hydrated films, solvent-induced fluctuations produce an ensemble of binding sites with similar characters. Therefore, upon hydration, the short-lifetime DAS becomes significantly red-shifted and inhomogeneously broadened. The similar spectral features have previously been observed for ANS complexed with globular proteins in solution. The data reveal the origin of the short-lifetime fluorescence component of ANS bound to the globular proteins in aqueous solution. Findings from this study indicate that ANS is applicable to characterize dehydrated as well as hydrated protein aggregates, amyloids relevant to amyloid diseases, such as Alzheimer's, Parkinson, and prion diseases.

Intracavitary ligand distribution in tear lipocalin by site-directed tryptophan fluorescence.

Site-directed tryptophan fluorescence has been successfully used to determine the solution structure of tear lipocalin. Here, the technique is extended to measure the binding energy landscape. Single Trp mutants of tear lipocalin are bound to the native ligand and an analogue tagged with a quencher group to both populate and discriminate the excited protein states. Steady-state and time-resolved fluorescence quenching data reveal the intracavitary state of the ligand. The static components of fluorescence quenching identify the residues where nonfluorescence complexes form. An asymmetric distribution of the ligand within the cavity reflects the complex energy landscape of the excited protein states. These findings suggest that the excited protein states are not unique but consist of many substates. The roughness of the binding energy landscape is about 2.5kBT. The excited protein states originate primarily from conformational selections of loops AB and GH, a portal region. In contrast to static quenching, the dynamic components of fluorescence quenching by the ligand are relevant to both local side chain and ligand dynamics. Apparent bimolecular rate constants for collisional quenching of Trp by the nitroxide moiety are approximately 1 / 5 x 10(12) M(-1) s(-1). Estimations made for effective ligand concentrations establish actual rate constants on the order of 12 x 10(9) M(-1) s(-1). Prior to exit from the cavity of the protein, ligands explore binding sites in nanoseconds. Although microsecond fluctuations are rate-limiting processes in ligand binding for many proteins, accompanying nanosecond motion may be necessary for propagation of ligand binding.

Stem cells and reproductive medicine.

For decades it has remained as a central dogma in dogma in reproductive biology that female mammals are born with a set non-renewable number of germ cells in the ovary. Recent revolutionary studies challenged this dogma by showing postnatal oogenesis in the adult ovary. In this review article the formation of primordial germ cells (PGC), the precursors of adult gametocytes beginning from their specification to their migration to prospective gonads will be reviewed with a special emphasis on stem cells studies that obtained gametocytes from germ and non germline stem cells.

ANS fluorescence: potential to augment the identification of the external binding sites of proteins.

8-anilino-1-naphthalenesulfonic acid (ANS) is believed to strongly bind cationic groups of proteins and polyamino acids through ion pair formation. A paucity of data exists on the fluorescent properties of ANS in these interactions. ANS binding to arginine and lysine derivatives was studied by fluorescence and circular dichroism spectroscopies to augment published information attained by isothermal titration calorimetry (ITC). Fluorescence enhancement with a hypsochromic shift results from the interaction of the charged group of lysine and arginine with the sulfonate group of ANS. Ion pairing between Arg (or Lys) and the sulfonate group of ANS reduce the intermolecular charge transfer (CT) rate constant that leads to enhancement of fluorescence. A positive charge near the -NH group of ANS changes the intramolecular CT process producing a blue shift of fluorescence. The Arg side chain compared to that of Lys more effectively interacts with both the -NH and sulfonate groups of ANS. ANS binding also induces a random coil-alpha helix transition in poly-Arg. Our data, in contrast to ITC results, indicate that electrostatic interactions between ANS derivatives and positively charged side chains do not account for binding affinity in the micromolar range. In addition to ion pairing complementary interactions, such as van der Waals, should be considered for high affinity (K(d)<1 mM) external binding sites of proteins.