Moonlighting Biochemistry of Cysteine Synthase: A Species-specific Global Regulator

Cysteine Synthase (CS), the enzyme that synthesizes cysteine, performs non-canonical regulatory roles by binding and modulating functions of disparate proteins. Beyond its role in catalysis and regulation in the cysteine biosynthesis pathway, it exerts its moonlighting effect by binding to few other proteins which possess a C-terminal "CS-binding motif", ending with a terminal ILE. Therefore, we hypothesized that CS might regulate many other disparate proteins with the "CS-binding motif". In this study, we developed an iterative sequence matching method for mapping moonlighting biochemistry of CS and validated our prediction by analytical and structural approaches. Using a minimal protein-peptide interaction system, we show that five previously unknown CS-binder proteins that participate in diverse metabolic processes interact with CS in a species-specific manner. Furthermore, results show that signatures of protein-protein interactions, including thermodynamic, competitive-inhibition, and structural features, highly match the known CS-Binder, serine acetyltransferase (SAT). Together, the results presented in this study allow us to map the extreme multifunctional space (EMS) of CS and reveal the biochemistry of moonlighting space, a subset of EMS. We believe that the integrated computational and experimental workflow developed here could be further modified and extended to study protein-specific moonlighting properties of multifunctional proteins.

Inhibitors of bacterial H2S biogenesis targeting antibiotic resistance and tolerance

Emergent resistance to all clinical antibiotics calls for the next generation of therapeutics. Here we report an effective antimicrobial strategy targeting the bacterial hydrogen sulfide (H2S)-mediated defense system. We identified cystathionine γ-lyase (CSE) as the primary generator of H2S in two major human pathogens, Staphylococcus aureus and Pseudomonas aeruginosa, and discovered small molecules that inhibit bacterial CSE. These inhibitors potentiate bactericidal antibiotics against both pathogens in vitro and in mouse models of infection. CSE inhibitors also suppress bacterial tolerance, disrupting biofilm formation and substantially reducing the number of persister bacteria that survive antibiotic treatment. Our results establish bacterial H2S as a multifunctional defense factor and CSE as a drug target for versatile antibiotic enhancers.

Molecular mechanism of selective substrate engagement and inhibitor disengagement of cysteine synthase

O-acetyl serine sulfhydrylase (OASS), referred to as cysteine synthase (CS), synthesizes cysteine from O-acetyl serine (OAS) and sulfur in bacteria and plants. The inherent challenge for CS is to overcome 4 to 6 log-folds stronger affinity for its natural inhibitor, serine acetyltransferase (SAT), as compared with its affinity for substrate, OAS. Our recent study showed that CS employs a novel competitive-allosteric mechanism to selectively recruit its substrate in the presence of natural inhibitor. In this study, we trace the molecular features that control selective substrate recruitment. To generalize our findings, we used CS from three different bacteria (Haemophilus, Salmonella, and Mycobacterium) as our model systems and analyzed structural and substrate-binding features of wild-type CS and its ∼13 mutants. Results show that CS uses a noncatalytic residue, M120, located 20 Å away from the reaction center, to discriminate in favor of substrate. M120A and background mutants display significantly reduced substrate binding, catalytic efficiency, and inhibitor binding. Results shows that M120 favors the substrate binding by selectively enhancing the affinity for the substrate and disengaging the inhibitor by 20 to 286 and 5- to 3-folds, respectively. Together, M120 confers a net discriminative force in favor of substrate by 100- to 858-folds.

Metal removal and recovery using bioelectrochemical technology: The major determinants and opportunities for synchronic wastewater treatment and energy production

Microbial fuel cell (MFC) technology has emerged as a new and attractive bioelectrochemical approach in the last one and a half decade that offers an alternative to conventional treatment methods to remove and recover heavy metals and organics from wastewaters with simultaneous energy production. This technique has advantage over the conventional wastewater treatment techniques, which are energy intensive, sludge producing and with little effectivity at high concentrations. Significant work has been done in the recent years on MFC principle, electrode configuration, biofilm composition, application of MFC in wastewater treatment, metal removal or recovery and energy production. Basically, metal in the cathode chamber acts as acceptor of the electrons released from the oxidation of organic matter in the anode chamber by electrogenic microbes. Literature shows that efficacy of MFCs in removal and recovery of metals and power production is significantly influenced by redox potential of the metal, initial concentration, mix metal systems, carbon source in substrate, pH, biocathode, biofilm composition, gaseous environment in cathode, electrode modification and external resistance, which have been critically reviewed for the first time in the present paper to understand the role of the determinant factors that may be explored for improvement of the MFC performance. The paper provides further insights into the techno-economic aspects of MFC technology and suggests research needs for enhanced performance and reduced costs to increase its feasibility for application at commercial level.

Conceptual framework of a skill-based interactive employee engaging system: In the Context of Upskilling the present IT organization

Skills form an integral part of an organization for its efficient functioning. This research study investigates mechanisms to actively persuade employees and organizations to change their attitudes and perspectives towards skills through the design and implementation of a skill-based system. The aim of the project is to know if we can create a skill-focused climate in a software organization through a software system proposed by the researcher and if such a system will help in utilizing in-house employees for new opportunities rather than hiring new employees. Feedback was collected on the proposed skill-based system from software professionals and human resource managers through an online survey. Findings reveal that the proposed skill-based system will create a skill-focused climate in a software organization and also help in better utilization of internal employees for new skill requirements rather than directly hiring external employees.

Emission characteristics of ultrafine particles from bare and Al2O3 coated graphite for high temperature applications

Owing to its exceptional properties at high temperature, graphite is used in several applications such as structural material and fuel block in high temperature nuclear reactors. Air ingress is one of the serious safety concerns in these reactors. Oxidation of graphite leading to increased porosity affects its mechanical strength and may lead to core collapse resulting in a severe accident. During such a scenario, generation of graphite particles could be the main hazard. Once generated, these particles often in fine and ultrafine sizes, may carry radioactivity to large distances and/or for long times. These particles owing to their higher surface to volume ratio possess an additional inhalation hazard. Ultrafine particles have the potential to enter into respiratory tract and cause damage to body organs. Coating of graphite components is preferred to reduce the oxidation induced damages at high temperatures. In the present work, effect of alumina (Al2O3) coating on the emission characteristics of particles from graphite under high temperature conditions has been investigated. Bare and Al2O3 coated graphite specimens were heated within a closed chamber at varying temperatures during these experiments. Temporal evolution of concentrations of gases (CO and CO2) and particles were measured. The results reveal that Al2O3 coating on the graphite delayed the oxidation behavior and the structure of graphite remained largely intact at high temperatures. A significant reduction in aerosol formation and CO emission was also noticed for the coated specimens.

Nano-enabled biosensing systems for intelligent healthcare: towards COVID-19 management

Biosensors are emerging as efficient (sensitive and selective) and affordable analytical diagnostic tools for early-stage disease detection, as required for personalized health wellness management. Low-level detection of a targeted disease biomarker (pM level) has emerged extremely useful to evaluate the progression of disease under therapy. Such collected bioinformatics and its multi-aspects-oriented analytics is in demand to explore the effectiveness of a prescribed treatment, optimize therapy, and correlate biomarker level with disease pathogenesis. Owing to nanotechnology-enabled advancements in sensing unit fabrication, device integration, interfacing, packaging, and sensing performance at point-of-care (POC) has rendered diagnostics according to the requirements of disease management and patient disease profile i.e. in a personalized manner. Efforts are continuously being made to promote the state of art biosensing technology as a next-generation non-invasive disease diagnostics methodology. Keeping this in view, this progressive opinion article describes personalized health care management related analytical tools which can provide access to better health for everyone, with overreaching aim to manage healthy tomorrow timely. Considering accomplishments and predictions, such affordable intelligent diagnostics tools are urgently required to manage COVID-19 pandemic, a life-threatening respiratory infectious disease, where a rapid, selective and sensitive detection of human beta severe acute respiratory system coronavirus (SARS-COoV-2) protein is the key factor.

Principles of RNA and nucleotide discrimination by the RNA processing enzyme RppH

All enzymes face a challenge of discriminating cognate substrates from similar cellular compounds. Finding a correct substrate is especially difficult for the Escherichia coli Nudix hydrolase RppH, which triggers 5′-end-dependent RNA degradation by removing orthophosphate from the 5′-diphosphorylated transcripts. Here we show that RppH binds and slowly hydrolyzes NTPs, NDPs and (p)ppGpp, which each resemble the 5′-end of RNA. A series of X-ray crystal structures of RppH-nucleotide complexes, trapped in conformations either compatible or incompatible with hydrolysis, explain the low reaction rates of mononucleotides and suggest two distinct mechanisms for their hydrolysis. While RppH adopts the same catalytic arrangement with 5′-diphosphorylated nucleotides as with RNA, the enzyme hydrolyzes 5′-triphosphorylated nucleotides by extending the active site with an additional Mg²⁺ cation, which coordinates another reactive nucleophile. Although the average intracellular pH minimizes the hydrolysis of nucleotides by slowing their reaction with RppH, they nevertheless compete with RNA for binding and differentially inhibit the reactivity of RppH with triphosphorylated and diphosphorylated RNAs. Thus, E. coli RppH integrates various signals, such as competing non-cognate substrates and a stimulatory protein factor DapF, to achieve the differential degradation of transcripts involved in cellular processes important for the adaptation of bacteria to different growth conditions.

Paediatric morphoea: a holistic review. Part 1: epidemiology, aetiopathogenesis and clinical classification

Morphoea, also known as localized scleroderma, is a debilitating fibrosing disorder of uncertain aetiology, affecting the skin and subcutaneous tissues. Paediatric-onset disease is not uncommon and is associated with frequent relapses. The disease has complex pathogenetic mechanisms and multiple clinical subtypes, and affects children of all ages. Recent research has focused on elucidating the disease pathophysiology and identifying measures of disease activity. We performed a literature search on PubMed, MEDLINE and Google Scholar, using keywords such as 'pediatric morphea', 'juvenile localised scleroderma' and 'juvenile systemic sclerosis'. Relevant studies, including randomized trials, reviews of standard current guidelines and original research articles, were selected, and results were analysed before being summarized. In the first of this two-part review, we provide a bird's-eye view of the current literature concerning the epidemiology, aetiopathogenesis and clinical classification of paediatric morphoea; in Part 2, we review the diagnosis, markers of disease activity, management and natural history.

Paediatric morphoea: a holistic review. Part 2: diagnosis, measures of disease activity, management and natural history

Paediatric morphoea is a debilitating fibrosing disorder of uncertain aetiology, affecting the skin and subcutaneous tissues. Defining optimum management strategies in paediatric morphoea remains an ongoing challenge, owing to the varied presentations and a relative paucity of paediatric-specific studies. We performed a literature search on PubMed, MEDLINE and Google Scholar, using keywords such as 'pediatric morphea', 'juvenile localised scleroderma' and 'juvenile systemic sclerosis'. Relevant studies, including randomized trials, reviews of standard current guidelines and original research articles, were selected and results analysed before summarizing them. In Part 1 of this review, we described the epidemiology, aetiopathogenesis and clinical classification; in this part, we discuss the diagnosis, markers of disease activity, management and natural history in paediatric morphoea.

Measuring stigma in children receiving mental health treatment: Validation of the Paediatric Self-Stigmatization Scale (PaedS)

Background:

Research on the impact of stigma associated with mental illness in children is scarce. Considering the known negative effects of stigma associated with mental illness in adults, it is crucial to explore the stigma experienced by children who access mental health treatment. However, no scale measuring self-stigmatization in younger children is available to date. This study aimed to develop and validate such a scale, the Paediatric Self-Stigmatization Scale (PaedS).

Methods:

A total of 156 children (119 receiving outpatient and 37 receiving inpatient treatment), aged 8–12 years, completed the PaedS, the Self-Perception Profile for Children and the Pediatric Quality of Life Inventory (PedsQL – Child Report, ages 8–12). In addition, parents completed the PedsQL (Parent Report for Children, ages 8–12), the Strengths and Difficulties Questionnaire (SDQ) and a modified subscale of the PaedS measuring the children's rejection by others due to their mental health difficulties.

Results:

A confirmatory factor analysis showed that a four-factor structure, comprising Societal Devaluation, Personal Rejection, Self-Stigma and Secrecy scales, had excellent fit to the data (CFI = 0.95; TLI = 0.95; RMSEA = 0.05). Child-reported PaedS scores were positively correlated with parental-reported PaedS scores and negatively with PedsQL, the SDQ, and 5 out of 6 subscales of the Self-Perception Profile for Children, suggesting adequate convergent validity (all P-values < 0.05).

Conclusions:

The PaedS is a valid instrument, which is hoped to advance the understanding of self-stigmatization in children with mental health difficulties and contribute to its prevention.

Robust marker detection and high precision measurement for real-time anatomical registration using Taguchi method

BACKGROUND

Accurate autonomous marker detection and measurement is essential for high precision anatomical registration. The measurement should be in real-time, accurate, and robust to the varied conditions of the operation theatre.

METHODS

The purpose is to design and implement a robust real-time algorithm to measure the coordinates of the point on the marker for robot-based autonomous registration and surgery. The algorithm is built in two parts based on the recursive Taguchi method. The first part deals with the detection of markers. In the second part, the center of the marker is located, and the coordinates are measured by fitting the concentric ellipse.

RESULTS

Three case studies are presented where the algorithm is tested for extreme conditions of uneven lighting, distorted color, surface distortions, and significant random orientation of the marker. The robustness of the algorithm in successfully detecting and measuring in real-time is presented.

CONCLUSION

The algorithm is successfully implemented for real-time detection and coordinate measurement of the markers.

Validation of High Precision Robot-Assisted Methods for Intracranial Applications: Preliminary Study

BACKGROUND

This work attempts to simulate a robot-based autonomous targeted neurosurgical procedure such as biopsy on a vegetable specimen. The objective of the work is to validate the robot-based autonomous neuroregistration and neuronavigation for neurosurgery in terms of stereotactic navigation and target accuracy.

CASE DESCRIPTION

A vegetable (carrot) fixed in a tray was used as a model. The tray was affixed with multiple markers. The robot autonomously registers the subject precisely and subsequently accesses the target. The navigation trajectory closely follows the path from the entry point to the target point, as specified in the medical image. The replication of procedures reveals that the target accuracies are within 1 mm. The results based on the case studies are presented. Intricate cases in terms of entry hole size, depth, and size of the target are considered for both phantom and vegetable trials.

CONCLUSIONS

The results of the case studies show enhanced and consistent performance characteristics in terms of accuracy, precision, and repeatability with the added advantage of the economy of time. The case studies serve as validation for a high precision robot-assisted neuroregistration and neuronavigation task for neurosurgery and pave the way for further animal and human trials.

P1496Use of strain, strain rate, tissue velocity imaging and endothelial function for early detection of cardiovascular involvement in young diabetics

Background

Subtle structural and functional changes may precede the onset of overt global left ventricular dysfunction and obvious reduction of ejection fraction (EF), especially in young diabetics. Data pertaining to tissue velocity indices (TVI) and strain imaging to assess regional myocardial function and flow mediated vasodilatation is limited in young patients with diabetes.

Purpose

To evaluate conventional echocardiography parameters, tissue doppler indices, global and regional strain, carotid intimal medial thickness (CIMT), endothelial dependent (FMD) and independent function (NMD) of brachial artery in young patients (age <18 years) with type 1 diabetes and compare them with matched controls.

Methods

Conventional echocardiography parameters, tissue velocity indices (TVI) parameters along with strain (S), and strain rate (SR) in basal and mid left ventricular (LV) lateral wall, right ventricular (RV) lateral wall and septum were measured in 50 young diabetics (age 15.16±2.95 years, mean HBA1c 8.15±1.37 gm %) and 25 controls (age 15.60±2.51 years). Flow-mediated dilatation (FMD), nitrate mediated dilatation and carotid intimal media thickness (CIMT) were also estimated.

Results

Conventional echocardiography parameters were similar in patients and controls however deceleration time of the mitral inflow velocity (EDT) was significantly shorter in patients when compared with controls (149.06±31.66 vs. 184.56±19.27 ms, p<0.05). Lateral early diastolic myocardial velocity (LV-Em) was significantly lower (10.30±0.99 vs. 11.67±3.21, p<0.05) whereas lateral late diastolic myocardial velocity (LV-Am) was significantly higher than controls (11.73±1.44 vs. 8.82±1.69, p<0.05), thus a significantly lower ratio of early/late diastolic velocity at the basal segment of lateral LV (LV-Em/Am). Lower strain values at the basal lateral LV (21.39±4.12 vs. 23.78±2.02; p<0.05), mid lateral LV (21.43±4.27 vs. 23.17±1.92; p<0.05), basal septum (20.59±5.28 vs. 22.91±2.00; p<0.05), and mid septum (22.06±4.75 vs. 24.10±1.99; p<0.05) as compared to controls. SR at the basal and mid segments of the lateral LV wall and at the basal septum were also significantly lower in diabetic subjects. Strain rate (SR) in mid septal, basal and mid RV were lower than controls although not statistically significant. Patients also had significantly lower flow mediated dilatation (FMD) (8.36±4.27 vs. 10.57±4.12, p<0.05) implying endothelial dysfunction.

Strain rate in diabetic patient

Conclusion

Left ventricular strain indices are impaired in asymptomatic children and adolescents with type 1 DM despite absence of overt heart failure and normal ejection fraction. Early detection of subclinical regional myocardial dysfunction by deformation analysis including strain and strain rate may be useful in the asymptomatic diabetic population. In addition, evidence of endothelial dysfunction in the form of impaired flow mediated vasodilatation was observed in the diabetic children.

Acknowledgement/Funding

None

Activated carbon from sugarcane bagasse ash for melanoidins recovery

This work investigates the value added utilization of two sugar-distillery wastes: (i) melanoidins, which are complex Maillard reaction products in molasses distillery wastewater, and (ii) unburnt carbon in sugarcane bagasse ash. Activated unburnt carbon (AUC), prepared by deashing and steam activation, had properties comparable to commercial activated carbon (CAC). Both carbons are suitable for melanoidins adsorption followed by desorption using 25% pyridine solution. For AUC, the equilibrium adsorption data is well described by Langmuir isotherm up to 35 °C while Freundlich model fits better at higher temperature. Adsorption using CAC followed Freundlich isotherm at all temperatures. Both carbons followed pseudo second order kinetics and displayed endothermic physisorption. Recovery of melanoidins from AUC (78%) was close to that observed with CAC (80%).

Substrate-Induced Facilitated Dissociation of the Competitive Inhibitor from the Active Site of O-Acetyl Serine Sulfhydrylase Reveals a Competitive-Allostery Mechanism

By classical competitive antagonism, a substrate and competitive inhibitor must bind mutually exclusively to the active site. The competitive inhibition of O-acetyl serine sulfhydrylase (OASS) by the C-terminus of serine acetyltransferase (SAT) presents a paradox, because the C-terminus of SAT binds to the active site of OASS with an affinity that is 4-6 log-fold (10⁴-10⁶) greater than that of the substrate. Therefore, we employed multiple approaches to understand how the substrate gains access to the OASS active site under physiological conditions. Single-molecule and ensemble approaches showed that the active site-bound high-affinity competitive inhibitor is actively dissociated by the substrate, which is not consistent with classical views of competitive antagonism. We employed fast-flow kinetic approaches to demonstrate that substrate-mediated dissociation of full length SAT-OASS (cysteine regulatory complex) follows a noncanonical "facilitated dissociation" mechanism. To understand the mechanism by which the substrate induces inhibitor dissociation, we resolved the crystal structures of enzyme·inhibitor·substrate ternary complexes. Crystal structures reveal a competitive allosteric binding mechanism in which the substrate intrudes into the inhibitor-bound active site and disengages the inhibitor before occupying the site vacated by the inhibitor. In summary, here we reveal a new type of competitive allosteric binding mechanism by which one of the competitive antagonists facilitates the dissociation of the other. Together, our results indicate that "competitive allostery" is the general feature of noncanonical "facilitated/accelerated dissociation" mechanisms. Further understanding of the mechanistic framework of "competitive allosteric" mechanism may allow us to design a new family of "competitive allosteric drugs/small molecules" that will have improved selectivity and specificity as compared to their competitive and allosteric counterparts.

A portable magneto-optical trap with prospects for atom interferometry in civil engineering

The high precision and scalable technology offered by atom interferometry has the opportunity to profoundly affect gravity surveys, enabling the detection of features of either smaller size or greater depth. While such systems are already starting to enter into the commercial market, significant reductions are required in order to reach the size, weight and power of conventional devices. In this article, the potential for atom interferometry based gravimetry is assessed, suggesting that the key opportunity resides within the development of gravity gradiometry sensors to enable drastic improvements in measurement time. To push forward in realizing more compact systems, techniques have been pursued to realize a highly portable magneto-optical trap system, which represents the core package of an atom interferometry system. This can create clouds of 10⁷ atoms within a system package of 20 l and 10 kg, consuming 80 W of power.This article is part of the themed issue 'Quantum technology for the 21st century'.

Two Distinct Assembly States of the Cysteine Regulatory Complex of Salmonella typhimurium Are Regulated by Enzyme-Substrate Cognate Pairs

Serine acetyltransferase (SAT) and O-acetylserine sulfhydrylase (OASS), which catalyze the last two steps of cysteine biosynthesis, interact and form the cysteine regulatory complex (CRC). The current model of Salmonella typhimurium predicts that CRC is composed of one [SAT]_hexamer unit and two molecules of [OASS]_dimer. However, it is not clear why [SAT]_hexamer cannot engage all of its six high-affinity binding sites. We examined the assembly state(s) of CRC by size exclusion chromatography, analytical ultracentrifugation (AUC), isothermal titration calorimetry (ITC), and surface plasmon resonance (SPR) approaches. We show that CRC exists in two major assembly states, low-molecular weight (CRC₁; 1[SAT]_hexamer + 2[OASS]_dimer) and high-molecular weight (CRC₂; 1[SAT]_hexamer + 4[OASS]_dimer) states. Along with AUC results, ITC and SPR studies show that [OASS]_dimer binds to [SAT]_hexamer in a stepwise manner but the formation of fully saturated CRC₃ (1[SAT]_hexamer + 6[OASS]_dimer) is not favorable. The fraction of CRC₂ increases as the [OASS]_dimer/[SAT]_hexamer ratio increases to >4-fold, but CRC₂ can be selectively dissociated into either CRC₁ or free enzymes, in the presence of OAS and sulfide, in a concentration-dependent manner. Together, we show that CRC is a regulatable multienzyme assembly, sensitive to OASS-substrate(s) levels but subject to negative cooperativity and steric hindrance. Our results constitute the first report of the dual-assembly-state nature of CRC and suggest that physiological conditions, which limit sulfate uptake, would favor CRC₁ over CRC₂.

Microglia-derived HIV Nef+ exosome impairment of the blood-brain barrier is treatable by nanomedicine-based delivery of Nef peptides

The negative factor (Nef) of human immunodeficiency virus (HIV) is an accessory protein that is thought to be integral to HIV-associated immune- and neuroimmune pathogenesis. Here, we show that nef-transfected microglia-released Nef+ exosome (exNef) disrupts the apical blood-brain barrier (BBB) and that only nef-transfected microglia release Nef in exosomes. nef-gfp-transduced neurons and astrocytes release exosomes but did not release exNef in the extracellular space. Apical administration of exNef derived from nef-transfected 293T cells reduced transendothelial electrical resistance (TEER) and increased permeability of the BBB. Microglia-derived exNef applied to either the apical/basal BBB significantly reduced expression of the tight junction protein, ZO-1, suggesting a mechanism of exNef-mediated neuropathogenesis. Microglia exposed to exNef release elevated levels of Toll-like receptor-induced cytokines and chemokines IL-12, IL-8, IL-6, RANTES, and IL-17A. Magnetic nanoparticle delivery of Nef peptides containing the Nef myrisolation site across an in vitro BBB ultimately reduced nef-transfected microglia release of Nef exosomes and prevented the loss of BBB integrity and permeability as measured by TEER and dextran-FITC transport studies, respectively. Overall, we show that exNef is released from nef-gfp-transfected microglia; exNef disrupts integrity and permeability, and tight junctions of the BBB, and induces microglial cytokine/chemokine secretion. These exNef-mediated effects were significantly restricted by Nef peptides. Taken together, this study provides preliminary evidence of the role of exNef in HIV neuroimmune pathogenesis and the feasibility of a nanomedicine-based therapeutics targeting exNef to treat HIV-associated neuropathogenesis.

Dentigerous Cysts of Maxillofacial Region– Clinical, Radiographic and Biochemical Analysis

Background Dentigerous cyst is the second most common type of odontogenic cysts that encloses the crown of an unerupted tooth by expansion of its follicle due to the collection of cystic fluid. In view of the capability of these lesions attaining a marked size if not diagnosed early and treated properly, the present study was done based on the clinical and radiographic presentation of the dentigerous cyst in addition to the analysis of the cystic contents.Objective The present study reported 14 cases of dentigerous cysts (DC) with their incidence and relative distribution of the maxillofacial region along with the clinical and radiographic features and biochemical analysis of cystic fluid.Method The study was conducted at Sri Govind Tricentenary Dental College, Hospital and Research Institute, Gurgaon, Haryana for a period of one year and six months. A detailed case history and thorough clinical examination was done for the patients who were provisionally found to have odontogenic cysts. Necessary radiographs, aspiration of the cystic fluid and incisional biopsy were performed to the 14 patients who were provisionally diagnosed with dentigerous cysts (DC) after obtaining the informed consent and the cystic fluid was subjected to biochemical analysis.Results Majority of the affected patients with DC were in their second decade and showed more predilection for mandible with a male predominance. The area of predilection was third molar region in the mandible and it is the canine region in maxilla. All the cases were associated with impacted teeth and majority showed expansion of the buccal/labial cortical plate. The various biochemical variables (total protein content, albumin, globulin and albumin: globulin ratio) were also assessed in the present study.Conclusion The awareness of protean features of DC evident through this study is essential for the general as well as specialty practitioners for the accurate diagnosis and proper treatment planning of these non cancerous but potentially destructive lesions and also opens new avenues for further research.Kathmandu University Medical Journal Vol.13(1) 2015; 8-11

Association of Mycobacterium tuberculosis in the causation of Eales' disease: an institutional experience

BACKGROUND

Eales' disease is an idiopathic retinal vasculitis characterized by retinal inflammation, ischemia, and neo-vascularisation. It frequently causes massive vitreous haemorrhage and retinal detachment leading to blindness. Although the exact etiology is unknown, this condition is considered to be a consequence of hypersensitivity reaction to tubercular protein due to previous Mycobacterium tuberculosis (M. tuberculosis) infection. This study is aimed at the detection of association of M. tuberculosis in patients with Eales' disease.

MATERIALS AND METHODS

A prospective case-control study was undertaken in 65 clinically diagnosed cases of Eales' disease. Patients with proliferative diabetic retinopathy, neo-vascular proliferation, macular oedema, premacular fibrosis and tractional retinal detachment were taken as controls. M. tuberculosis DNA was detected (MPT64 gene by polymerase chain reaction, PCR) in patients with Eales' disease. Clinical symptoms along with tuberculin skin test (TST) and erythrocyte sedimentation rate (ESR) were used as gold standard for comparing results of PCR.

RESULT

PCR positivity was found in 12 (38.7%) patients with Eales' disease. The PCR positivity was significantly associated with the patients with high TST reading and high ESR values.

CONCLUSION

Patients with a high TST reading and ESR value and a positive PCR in vitreous samples have a high likelihood of having M. tuberculosis as an etiology.

Effect of thyroid on lipid profile and renal function: an observational study from tertiary care centre of tribal region of bastar

Background:

Thyroid hormone is a key substance in normal homeostasis, having variable influence on cell metabolism on different organs. Very little is known about the prevalence of thyroid disorders from our region.

Aim:

This study was conducted with the aim of finding prevalence of thyroid disorder and relation of thyroid hormone with renal function and cholesterol metabolism.

Subjects and Methods:

A total of 96 ambulatory patients were taken for study. Serum samples were collected and evaluated for triiodothyronine, thyroxine, thyroid-stimulating hormone, urea, creatinine, total cholesterol, triglyceride (TG), low density lipoprotein (LDL), very low density lipoprotein and high density lipoprotein (HDL). Analysis of variance and t-test were used to find a significant difference among the groups.

Results:

Prevalance of thyroid disorder among suspected patients was 64/96 (66%), of which 36/64 (56.3%) were hypothyroid and 28/64 (43.8%) were hyperthyroid. No relation was found with renal function, but cholesterol was found high (>250 mg/dl) among hypothyroid patients and significant increase in TG, LDL levels and significant decrease was in HDL.

Conclusion:

Thyroid disorder is high among subjects with hypercholesterolemia. This underscores the need to evaluate for thyroid disorder in hypercholesterolemic patients and vice-versa.