Understanding role of pesticides in development of Parkinson's disease: Insights from Drosophila and rodent models.

Parkinson's disease is a neurodegenerative illness linked to ageing, marked by the gradual decline of dopaminergic neurons in the midbrain. The exact aetiology of Parkinson's disease (PD) remains uncertain, with genetic predisposition and environmental variables playing significant roles in the disease's frequency. Epidemiological data indicates a possible connection between pesticide exposure and brain degeneration. Specific pesticides have been associated with important characteristics of Parkinson's disease, such as mitochondrial dysfunction, oxidative stress, and α-synuclein aggregation, which are crucial for the advancement of the disease. Recently, many animal models have been developed for Parkinson's disease study. Although these models do not perfectly replicate the disease's pathology, they provide valuable insights that improve our understanding of the condition and the limitations of current treatment methods. Drosophila, in particular, has been useful in studying Parkinson's disease induced by toxins or genetic factors. The review thoroughly analyses many animal models utilised in Parkinson's research, with an emphasis on issues including pesticides, genetic and epigenetic changes, proteasome failure, oxidative damage, α-synuclein inoculation, and mitochondrial dysfunction. The text highlights the important impact of pesticides on the onset of Parkinson's disease (PD) and stresses the need for more research on genetic and mechanistic alterations linked to the condition.

Protein disulfide isomerase uses thrombin-antithrombin complex as a template to bind its target protein and alter the blood coagulation rates.

During inflammation and situations of cellular stress protein disulfide isomerase (PDI) is released in the blood plasma from the platelet and endothelial cells to influence thrombosis. The addition of exogenous PDI makes the environment pro-thrombotic by inducing disulfide bond formation in specific plasma protein targets like vitronectin, factor V, and factor XI. However, the mechanistic details of PDI interaction with its target remain largely unknown. A decrease in the coagulation time was detected in activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) on addition of the purified recombinant PDI (175 nM). The coagulation time can be controlled using an activator (quercetin penta sulfate, QPS) or an inhibitor (quercetin 3-rutinoside, Q3R) of PDI activity. Likewise, the PDI variants that increase the PDI activity (H399R) decrease, and the variant with low activity (C53A) increases the blood coagulation time. An SDS-PAGE and Western blot analysis showed that the PDI does not form a stable complex with either thrombin or antithrombin (ATIII) but it uses the ATIII-thrombin complex as a template to bind and maintain its activity. A complete inhibition of thrombin activity on the formation of ATIII-thrombin-PDI complex, and the complex-bound PDI-catalyzed disulfide bond formation of the target proteins may control the pro- and anti-thrombotic role of PDI.

Exploring Underrepresentation: The Role of Diversity Statements in Ophthalmology Residency Programs.

INTRODUCTION: The underrepresentation of underrepresented minorities (URMs) in the medical field, particularly in ophthalmology, poses a critical challenge to achieving diversity and equity. While URMs constitute 19% of medical school attendees, their presence is markedly lower in ophthalmology residency programs and among practicing ophthalmologists. This study seeks to investigate the prevalence of diversity statements on ophthalmology residency program websites and their role in the underrepresentation of URMs within the field. METHODS: This observational, cross-sectional study analyzed the websites of 126 ophthalmology residency programs listed on the San Francisco (SF) Match website. Diversity statements were categorized based on their inclusion of specific underrepresented groups (race or ethnicity, gender, sexual orientation, and disability) and analyzed for correlation with program characteristics. Descriptive statistics and Chi-squared tests were utilized to assess the prevalence of diversity statements and their association with program size, ranking, geographical location, and institutional nature. RESULTS: Of the 126 programs analyzed, 21 (16.7%) had diversity statements specific to the ophthalmology residency program, and 115 (91.3%) featured institutional-level diversity statements. Race or ethnicity was the most commonly addressed category in diversity statements (75.3%), followed by gender (65.9%), sexual orientation (61.1%), and disability (53.2%). Statistical analyses revealed no significant correlation between program size and the presence of diversity statements. However, higher-ranked programs were more likely to mention sexual orientation and disability. Significant differences were observed at the institutional level, with public institutions more likely to include specific diversity categories. CONCLUSION: The study highlights a significant disparity in the presence and focus of diversity statements across ophthalmology residency programs. Despite a high prevalence of institutional-level diversity statements, program-specific initiatives are lacking, particularly in addressing disability inclusion. The findings suggest a need for a more comprehensive and targeted effort to address underrepresentation in ophthalmology.

A common protein C inhibitor exosite partially controls the heparin induced activation and inhibition of serine proteases.

Protein C inhibitor (PCI) maintains hemostasis by inhibiting both procoagulant and anticoagulant serine proteases, and plays important roles in coagulation, fibrinolysis, reproduction, and anti-angiogenesis. The reactive site loop of PCI traps and irreversibly inhibits the proteases like APC (activating protein C), thrombin (FIIa) and factor Xa (FXa). Previous studies on antithrombin (ATIII) had identified Tyr253 and Glu255 as functional exosites that interact and aid in the inhibition of factor IXa and FXa. Presence of exosite in PCI is not known, however a sequence comparison with the PCI from different vertebrate species and ATIII identified Glu239 to be absolutely conserved. PCI residues analogous to ATIII exosite residues were mutated to R238A and E239A. Purified variant PCI in the presence of heparin (10 µg/ml) showed a 2-4 fold decrease in the rate of inhibition of the proteases. However, the stoichiometry of inhibition of FIIa, APC, and FXa by native PCI, R238A and E239A variants were found to be close to 1.0, which also indicated the formation of stable complexes based on SDS-PAGE and western blot analysis with thrombin and APC. Our findings revealed the possible presence of an exosite in PCI that influences the protease inhibition rates.

Naringin binds to protein disulfide isomerase to inhibit its activity and modulate the blood coagulation rates: Implications in controlling thrombosis.

Currently used antithrombotic drugs are beset with several drawbacks which necessitates the need for new and cheaper alternatives. Protein disulfide isomerase (PDI) is secreted in the blood plasma in cellular stress conditions and initiates the thrombus formation. A screening of library of natural compounds revealed that naringin had a high binding affinity for the PDI (-8.2 kcal/mol). Recombinant PDI was purified using the affinity chromatography. Incubation of purified PDI (3 µM) with naringin (0-100 µM, pH 7.4, 25 °C) partially modulated its conformation. Consequently, the fluorescence emission spectra of the PDI binding to naringin were assessed using the Stern-Volmer equation, which indicated an association constant of 2.78 × 104 M-1 suggesting an appreciable affinity for the naringin, with a unique binding site. An insulin turbidity assay showed that PDI activity is decreased in the presence of naringin indicating inhibition. Molecular dynamic simulation studies showed the changes in the PDI structure on binding to the naringin. Incubation of naringin (80 µM) in fresh human plasma along with exogenous PDI (175 nM) showed a significant delay in the intrinsic and extrinsic coagulation pathways. We show that naringin is able to modulate the PDI conformation and activity resulting in altered blood coagulation rates.

Protective Effect of Catharanthus roseus Extract on Cadmium-Induced Toxicity in Albino Rats: A Putative Mechanism of Detoxification.

Globally, people are highly affected by Cadmium (Cd), the most hazardous heavy metal. It has been implicated in various pathogeneses. Oxidative stress may be one the main reasons for Cd-induced disorders in the body. This article investigates the protective ability of Catharanthus roseus (CR) extract on oxidative stress in the kidney and liver of rats exposed to Cd. After 21 days, a significant increase in MDA concentration (6.81 ± 0.05), (6.64 ± 0.03) was observed in Cd-treated groups compared to the control (5.54 ± 0.02), (5.39 ± 0.04) for the kidney and liver, respectively, while significant changes were observed in the haematological parameters. Antioxidant enzymes, GPx, CAT, and SOD showed a significant decrease in their activity. We established that increasing the concentration of Cd in the presence of H2O2 was able to cause stand scission in pBR322 plasmid DNA, which may be due to the mediation of ROS generated in the process. The antioxidant ability of CR extract was tested in DPPH and H2O2 scavenging assay, depicted by the increase in the percentage inhibition. Upon treatment of CR extract to rats, MDA concentration was decreased for the kidney and liver compared to the Cd-treated groups. This was again confirmed by comet assay of both tissues, where the degree of cellular DNA breakage caused by Cd toxicity decreased significantly upon treatment with CR extract. Overall, the results suggest that Cd plays a major role as an effector metal ion, causing a decrease in the concentration and activity of AO enzymes and enhanced lipid peroxidation. ROS production resulted in oxidative DNA damage within the cell, whereas CR extract showed potential antioxidant activity against ROS-mediated DNA damage induced by Cd poisoning.

Correlation between Salivary Levels of IGF-1, IGFBP-3, IGF-1/IGFBP3 Ratio with Skeletal Maturity Using Hand-Wrist Radiographs.

Objective: The relevance of growth determination in orthodontics is driving the search for the most precise and least invasive way of tracking the pubertal growth spurt. Our aim was to explore whether minimally invasive salivary estimation of biomarkers Insulin-like growth factor (IGF-1) and Insulin-like growth factor binding protein-3 (IGFBP-3) could be used to estimate skeletal maturity for clinical convenience, especially in children and adolescent age groups. Materials and Method: The cross-sectional study was conducted on 90 participants (56 girls and 34 males) with ages ranging from 6 to 25 years. Each subject's hand-wrist radiograph was categorized based on skeletal maturity, and saliva samples were estimated for IGF-1 and IGFBP-3 using the respective ELISA kits. Kruskal−Wallis nonparametric ANOVA was applied to compare different skeletal stages. Results: The study demonstrated low salivary IGF-1 levels at the prepubertal stage, with increase during pubertal onset and peak pubertal stage followed by a decline during pubertal deceleration to growth completion. Spearman's correlation coefficient demonstrated a strong positive association (r = 0.98 p < 0.01) between salivary IGF/IGFBP-3 ratio and different stages of skeletal maturity. Conclusion: Salivary IGF-1, IGFBP-3, and IGF/IGFBP-3 ratio could serve as a potential biochemical marker for predicting the completion of skeletal maturity.

Arabian undergraduates perceptions regarding barriers among the geriatric patients for failing to keep dental appointments: A cross-sectional study.

BACKGROUND: Regular visits to the health care providers can develop a relationship that can extend beyond the physical health alone as the patient is transiting towards older age, adapting to changes in physical health, emotional health, and social connections. Apart from limiting access to health care services, the attitudes, beliefs, comfort level of the treating doctors towards the geriatric patients can motivate or demotivate them to access dental care. AIM: To explore the Saudi Arabian undergraduate students perception of geriatric patients and identify potential barriers that prevent the utilization of their dental appointment. METHODS: A close-ended questionnaire with one question and eight reasons was administered to the fifth year clinical students. The students were requested to specify their agreement with each question on a 5-point Likert scale. Among the barriers presented, each reason's approval was expressed as the percentage of the total number of responses. In addition, the gender comparison of mean scores was made, and an independent sample t-test was used to analyze the statements agreed by the students. All analyses were performed using Statistical Package of Social Sciences (SPSS) version 21.0 (IBM, USA) with the probability of statistical significance at 0.05 level. RESULTS: Fifty-one students recorded their perceptions on the questionnaire administered during their clinical posting in the fifth year of the geriatric dental education program. It was concluded that students believed that geriatric patients give overwhelming importance to other problems with minor importance to oral health care. In addition, gender comparison was more evident as the percentage expressed was more in females. CONCLUSIONS: There is a need for more clinical exposure of geriatric patients during their clinical postings. Student's acquaintance with didactic and clinical settings appears to be a critical element towards positive knowledge and attitude towards the geriatric population.

Auto-controlled Syringe vs Insulin Syringe for Palatal Injections in Children: A Randomized Crossover Trial.

AIM: This study aims to evaluate and compare the efficacy of auto-control syringe (ACS) and insulin syringe (IS) for palatal local anesthesia administration in children. MATERIALS AND METHODS: The study was a double-blind, randomized, and crossover trial, comprising 80 children requiring palatal anesthesia bilaterally (total 160 injections). Palatal anesthesia on one side was delivered with ACS in one appointment and contralaterally with IS in the second appointment. One-week washout period was given between first and second appointments. Each child acted as his own control. Each injection technique subjective and objective pain scores were measured twice (during needle prick and during actual deposition of local anesthesia). Subjective and objective evaluation of pain was measured with Wong-Baker FACES pain rating scale (WB-FPS) and the face, leg, activity, cry, and consolability scale (FLACC), respectively. After concluding second appointment, child was asked about their preference between both ACS and IS. Statistical evaluation was performed using Chi-square test. RESULTS: Child reported less pain score for needle prick with IS as opposed to ACS (p value = 0.000416). There was no significant difference between dentist-reported pain scores between any group for both needle prick and local anesthesia administration. There is no significant difference between child reported pain score during administration of local anesthesia between two groups. Irrespective of pain scores, most of the children (96.5%) preferred IS. CONCLUSION: For palatal local anesthesia administration in children, both IS and auto-controlled syringe have similar efficacy. CLINICAL SIGNIFICANCE: Insulin syringe can serve as an economical alternative to the expensive auto-controlled syringe for palatal injections in children.

Flavonoids-induced redox cycling of copper ions leads to generation of reactive oxygen species: A potential role in cancer chemoprevention.

Flavonoids, a class of polyphenols are known to be effective inducers of apoptosis and cytotoxicity in cancer cells. It is believed that antioxidant activity of polyphenols cannot fully account for induction of apoptosis and chemotherapeutic prevention in various cancers. In this article, by employing single cell alkaline gel electrophoresis (comet assay), we established that antioxidants, flavonoids such as (myricetin=MN, fisetin=FN, quercetin=QN, kaempferol=KL and galangin=GN) can cause cellular DNA breakage, also act as pro-oxidant in presence of transition metal ion such as copper. It was observed that the extent of cellular DNA breakage was found significantly higher in presence of copper. Hydroxyl radicals are generated as a sign of flavonoids' pro-oxidant nature through redox recycling of copper ions. Further, a dose-dependent inhibition of proliferation of breast cancer cells MDA-MB-231 by MN was found leading to pro-oxidant cell death, as assessed by MTT assay. Since levels of copper are considerably elevated in tissue, cell and serum during various malignancies, suggesting that cancer cells would be more subject to copper induced oxidative DNA breakage. Such a copper dependent pro-oxidant cytotoxic mechanism better explains the anticancer activity and preferential cytotoxicity of dietary phytochemicals against cancer cells.

Chemotherapeutic Drugs and Plasma Proteins: Exploring New Dimensions.

In the last few decades, advances in the cancer chemotherapy have been a marked success. A large number of anticancer drugs currently in use include drugs based on platinum complexes such as cisplatin, base analogues such as 5-florouracil and some ruthenium drugs. This review provides a bird's eye view of interaction of a number of clinically important drugs currently in use that show covalent or non-covalent interaction with serum proteins. Platinum drug-cisplatin interacts covalently and alters the function of the key plasma protease inhibitor molecule -alpha-2-macroglobulin and induces the conformational changes in the protein molecule and inactivates it. 5-fluorouracil (5-FU) is extensively metabolized and at physiological concentrations, is found to be associated with Human Serum Albumin (HSA). Similarly ruthenium compounds bind tightly to plasma proteins- serum albumin and serum transferrin, modifying their biological activity and increasing the toxicity of drug to cancer cells. Insight into varied anticancer drug- protein interaction will go a long way in understanding in totality of the mechanism of action of any anticancer drug and its possible effects/side effects.

Conformational behavior of alpha-2-macroglobulin: Aggregation and inhibition induced by TFE.

Alpha-2-macroglobulin (α2M), a pan-proteinase inhibitor, inhibits a variety of endogenous and exogenous proteinases and constitutes an important part of body's innate defense system. In the present study, we explored how trifluoroethanol (TFE) may modulate the structure, antiproteinase activity and aggregation of α2M. TFE was sequentially added over a range of 0-20% (v/v) and the effects induced were studied by activity assay, intrinsic fluorescence, ANS fluorescence, circular dichroism, turbidity assay, Rayleigh scattering measurement and ThT fluorescence measurement. Decrease in activity and increase in fluorescence intensity of α2M upon addition of TFE shows structural deviation from the native structure and suggests aggregation of protein upon solvent addition. Increase in turbidity and Rayleigh scattering of modified α2M confirms the formation of aggregates. Insignificant ThT fluorescence intensity of TFE treated α2M is indicative of amorphous or non-amyloid aggregation. Further, circular dichroism results indicate the changes in secondary structure of native α2M as negative ellipticity decreased on addition of the polar solvent to the inhibitor. The turbidometric analysis, Rayleigh scattering, ThT fluorescence intensity of modified α2M suggests that the protein might be driven towards non-amyloid or amorphous aggregation. Our studies provide important mechanistic insight how α2M undergoes conformational and functional changes when exposed to TFE.

Identification of a new alpha-2-macroglobulin: Multi-spectroscopic and isothermal titration calorimetry study.

A α2M homologue was isolated from sheep (Ovis aries) blood plasma, using a simple two-step procedure, ammonium sulphate fractionation and gel filtration chromatography. Sheep α2M was found to be a large tetrameric glycoprotein of 630 kDa with monomeric subunit of 133 kDa each. Each subunit of sheep α2M was found to be made up of two fragments of 102 and 31 kDa respectively. The proteinase inhibitor from sheep was found to have Stokes radius of 79Ǻ, which makes it much more compact than its human homologue. It entraps only 1 mol of trypsin per mole of inhibitor, like its caprine counterpart. The use of isothermal titration calorimetry has become gold standard for exploring thermodynamics of binding interactions. In this study, binding interaction of trypsin with alpha-2-macroglobulin is studied using ITC. The thermodynamic signatures--enthalpy change (ΔH), entropy change (ΔS) and Gibb's free energy change (ΔG), along with number of binding sites (N) and affinity constant (K) are explored for α2M-trypsin binding for the first time for any known α2M molecule. The thermodynamics of proteinase-antiproteinase association suggests that trypsin-α2M interaction is enthalpy driven event.

Reactive oxygen species and anti-proteinases.

Reactive oxygen species (ROS) cause damage to macromolecules such as proteins, lipids and DNA and alters their structure and function. When generated outside the cell, ROS can induce damage to anti-proteinases. Anti-proteinases are proteins that are involved in the control and regulation of proteolytic enzymes. The damage caused to anti-proteinase barrier disturbs the proteinase-anti-proteinases balance and uncontrolled proteolysis at the site of injury promotes tissue damage. Studies have shown that ROS damages anti-proteinase shield of the body by inactivating key members such as alpha-2-macroglobulin, alpha-1-antitrypsin. Hypochlorous acid inactivates α-1-antitrypsin by oxidizing a critical reactive methionine residue. Superoxide and hypochlorous acid are physiological inactivators of alpha-2-macroglobulin. The damage to anti-proteinase barrier induced by ROS is a hallmark of diseases such as atherosclerosis, emphysema and rheumatoid arthritis. Thus, understanding the behaviour of ROS-induced damage to anti-proteinases may helps us in development of strategies that could control these inflammatory reactions and diseases.

α-2-Macroglobulin: a physiological guardian.

Alpha macroglobulins are large glycoproteins which are present in the body fluids of both invertebrates and vertebrates. Alpha-2-macroglobulin (α2 M), a key member of alpha macroglobulin superfamily, is a high-molecular weight homotetrameric glycoprotein. α2 M has many diversified and complex functions, but it is primarily known by its ability to inhibit a broad spectrum of proteases without the direct blockage of the protease active site. α2 M is also known to be involved in the regulation, transport, and a host of other functions. For example, apart from inhibiting proteinases, it regulates binding of transferrin to its surface receptor, binds defensin and myelin basic protein, etc., binds several important cytokines, including basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), nerve growth factor (NGF), interleukin-1ß (IL-1ß), and interleukin-6 (IL-6), and modify their biological activity. α2 M also binds a number of hormones and regulates their activity. α2 M is said to protect the body against various infections, and hence, can be used as a biomarker for the diagnosis and prognosis of a number of diseases. However, this multipurpose antiproteinse is not "fail safe" and could be damaged by reactive species generated endogenously or exogenously, leading to various pathophysiological conditions.

Efficacy of cervicothoracic sympathectomy versus conservative management in patients suffering from incapacitating Raynaud's syndrome after frost bite.

BACKGROUND: Raynaud's syndrome is a known complication of cold injuries. Stress, smoking and metabolic diseases may further aggravate the disease course. The purpose of this study was to determine the efficacy of Cervico-thoracic sympathectomy as compared to conservative management in severe Raynaud's syndrome after frostbite. METHODS: This non-randomized controlled trial was conducted at Railway Hospital, Rawalpindi and Islamic International Medical Complex, Islamabad between January 1999 and June 2006. All patients sustained severe cold trauma in the mountain ridges of Himalayas in Kashmir. In all cases, an informed consent was obtained from patients and families. All operations performed were free of charges. Out of the total 48 patients who developed incapacitating Raynaud's syndrome of the upper limbs after frost bite, 17 patients underwent thoracic sympathectomy through anterior supraclavicular route. Remaining 31 patients were treated conservatively and were placed in the control group. Data was collected on pre-designed proforma and assessed using SPSS (version 11). Chi-square test was applied to assess the effectiveness of the two treatment modalities. RESULTS: All operated cases initially showed improvement in symptoms and incapacitation. Among sympathectomised patients, 11 patients became symptom free and 3 patients showed mild but improved symptoms. Two patients after initial transient improvement developed incapacitating symptoms requiring further treatment, one patient developed gangrene ofdistal phalanx nine month after sympathectomy requiring amputation of the finger. Frequency of attacks and duration between the attacks reduced in all operated patients of cervical sympathectomy (p < 0.05) as compared to conservative management. CONCLUSION: Cervical sympathectomy is a very effective modality of treatment in patients having severe Raynaud's disease of upper limbs secondary to frost bite.

Extracorporeal shock wave lithotripsy.

OBJECTIVE: To determine the outcome of patients undergoing extracorporeal shock wave lithotripsy (ESWL) for treatment of upper urinary tract calculi (renal and ureteric), and to note role of double-J (DJ) stents in these patients. DESIGN: A cross-sectional analytical study. PLACE AND DURATION OF STUDY: Department of Urology, Rawalpindi General Hospital, Rawalpindi, from February 1999 to July 2001. PATIENTS AND METHODS: Record of patients who underwent ESWL for renal and ureteric stones was retrieved and analyzed using statistical program, SPSS version-10 and Epi-Info 2000. In some patients pre-ESWL DJ stents were placed because of various reasons like solitary kidney, large stone volume etc. Patients were divided in two groups, Group I, in whom DJ stents were not placed, and Group II, in whom DJ stents were placed. ESWL was performed in each subject in standard way employing piezoelectric lithotripter E.D.A.P. LT 02X. Patients were evaluated for stone clearance fortnightly with X-ray or ultrasound. RESULTS: Four hundred and thirty-two patients, 68.8% male and 31.2% female, underwent ESWL. Mean age of patients was 37.7 +/- 13.1 years. Majority of patients (78.47%, n = 339) had renal, while rest had ureteric stones. Group I and II included 408 (94.4%) and 24 (5.6%) patients respectively. Renal stones were present in 78% (n=318) of Group I and 87.5% [n = 21] of Group II patients. Mean size of stones in Group I and II patients was 10.91 +/- 4.6, and 10.4 +/- 4.7mm. Stone clearance was 96.3% and 100% in Group I and Group II patients respectively. Significantly more ESWL sessions were required for stone clearance in Group II (p-value 0.03); in addition Group II patients had significantly more complications (p-value 0.01). CONCLUSION: ESWL is an effective procedure. Pre-ESWL stenting is associated with increased numbers of ESWL sessions and more complications.