Microhydration of small protonated polyaromatic hydrocarbons: a first principles study.

Using first principles methodology, we investigate the microsolvation of protonated benzene (BzH+), protonated coronene (CorH+) and protonated dodecabenzocoronene (DbcH+). Gas phase complexes of these small protonated polyaromatic hydrocarbons (H+PAHs) with mono-, di-, and tri-hydrated water molecules are considered. Their most stable forms are presented, where we discuss their structural, energetic aromaticity and IR and UV spectral features. In particular, we focus on the analysis of the bonding and various non-bonded interactions between these protonated aromatics and water clusters. The strength of non-bonded interactions is quantified and correlated with their electron density profiles. Furthermore, insights into the interfacial interactions and stability of these complexes were obtained through non-covalent index and symmetry-adapted perturbation theory (SAPT0) analyses. We also discuss the effects of the extension of the π aromatic cloud on the water solvation of these protonated aromatics. In particular, we extended our predictions for the S0 → S1 and S0 → T1 wavelength transitions of micro hydrated H+PAHs to deduce those of these species solvated in aqueous solution. The present findings should be useful for understanding, at the microscopic level, the effects of water interacting with H+PAHs, which are relevant for organic chemistry, astrochemistry, atmospheric chemistry, combustion and materials science.

Metformin use and risk of lactic acidosis in people with diabetes with and without renal impairment: a cohort study in Denmark and the UK.

AIMS: To assess risk of lactic acidosis among metformin users compared with other glucose-lowering agent users, according to renal function. METHODS: Using routine registries and databases, we conducted a cohort study. Of 43 580 metformin and 37 788 other glucose-lowering agent users in northern Denmark and 102 688 metformin and 28 788 other glucose-lowering agent users in the UK during 2001-2011, we identified lactic acidosis using diagnostic codes. We calculated the incidence rates of lactic acidosis in metformin and other glucose-lowering agent users overall and according to baseline estimated GFR (eGFR) levels. RESULTS: In Denmark, the incidence rates of lactic acidosis were 11.6 (95% CI 7.0-18.1) and 1.8 (95% CI 0.4-5.4) per 100 000 person-years of metformin use and of other glucose-lowering agent use, respectively. In the UK, the corresponding lactic acidosis incidence rates were 6.8 (95% CI 4.6-9.6) and 1.0 (95% CI 0.01-5.7) per 100 000 person-years of metformin use and of other glucose-lowering agent use. The incidence rates increased with decreasing baseline eGFR in both countries. Of the metformin-exposed people with lactic acidosis, 37% in Denmark and 34% in the UK experienced a decline in renal function in the year before the diagnosis. CONCLUSIONS: Risk of lactic acidosis was higher in metformin users than in other glucose-lowering agent users, and increased with decreasing eGFR, although this could be attributable to surveillance bias; however, diagnosed lactic acidosis was rare and can occur regardless of renal function.

Comparative cardiovascular safety of glucagon-like peptide-1 receptor agonists versus other antidiabetic drugs in routine care: a cohort study.

AIMS: To evaluate the comparative cardiovascular disease (CVD) safety of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) in head-to-head comparisons with dipeptidyl peptidase-4 (DPP-4) inhibitors, sulphonylureas or insulin, when added to metformin, as used in 'real-world' patients with type 2 diabetes mellitus (T2DM). METHODS: Within a large US commercial health plan database linked to laboratory test results, we identified three pairwise 1 : 1 propensity-score-matched cohorts of patients with T2DM aged ≥18 years treated with metformin who initiated a GLP-1 RA or a comparator, i.e. DPP-4 inhibitor (n = 35 534), second-generation sulphonylureas (n = 28 138) or insulin (n = 47 068), between 2005 and 2013. We examined the association between drug initiation and a composite CVD endpoint, comprising hospitalizations for acute myocardial infarction, unstable angina, stroke or coronary revascularization. RESULTS: During the course of 1 year, there were 13.9 and 13.7 CVD events per 1000 person-years among propensity-score-matched initiators of GLP-1 RAs versus DPP-4 inhibitors [hazard ratio (HR) 1.02; 95% confidence interval (CI) 0.84-1.24]; and 12.1 versus 14.0 events among initiators of GLP-1 RAs versus sulphonylureas (HR 0.86; 95% CI 0.69-1.08). The effect estimates for GLP-1 RAs versus insulin were sensitive to the adjustment for glycated haemoglobin, after which the HR was 1.01 (95% CI 0.73-1.41). Results were robust across several sensitivity analyses, including an as-treated analysis considering up to 8.7 years of follow-up. CONCLUSIONS: This large study, performing head-to-head comparisons of GLP-1 RAs with other antidiabetic agents in real-world patients, provides estimates of relative safety precise enough to exclude large differences in CVD risk and adds further understanding to results from recent clinical trials.

Current approaches, and challenges on identification, remediation and potential risks of emerging plastic contaminants: A review.

Plastics are widely employed in modern civilization because of their durability, mold ability, and light weight. In the recent decade, micro/nanoplastics research has steadily increased, highlighting its relevance. However, contaminating micro/nanoplastics in marine environments, terrestrial ecosystems, and biological organisms is considered a severe threat to the environmental system. Geographical distribution, migration patterns, etymologies of formation, and ecological ramifications of absorption are just a few topics covered in the scientific literature on environmental issues. Degradable solutions from material science and chemistry are needed to address the micro/nanoplastics problem, primarily to reduce the production of these pollutants and their potential effects. Removing micro/nanoplastics from their discharge points has been a central and effective way to mitigate the adverse pollution effects. In this review, we begin by discussing the hazardous effect on living beings and the identification-characterization of micro/nanoplastics. Then, we provide a summary of the existing degradation strategies, which include bio-degradation and advanced oxidation processes (AOPs), and a detailed discussion of their degradation mechanisms is also represented. Finally, a persuasive summary of the evaluated work and projections for the future of this topic is provided.

Factors predicting the need for cerebrospinal fluid diversion following posterior fossa tumor surgery in children.

BACKGROUND: No consensus exists regarding the management of hydrocephalus in children with posterior fossa tumors before, during or after surgery. In the present study we analyze the factors that predispose to persistent hydrocephalus and the need for a postoperative cerebrospinal fluid (CSF) diversion procedure. METHODS: Pediatric patients who underwent surgery for posterior fossa tumors with hydrocephalus at our hospital were reviewed to evaluate the need for a postoperative CSF diversion procedure. Patients having undergone CSF diversion preoperatively were excluded from the study group. The case records of 84 patients were reviewed. The factors evaluated included age at diagnosis, duration of symptoms, severity of preoperative hydrocephalus, tumor size, tumor location, tumor histology, extent of tumor resection and postoperative complications that could be related to CSF circulation disorders. RESULTS: At the time of presentation, 80/84 (95.2%) patients had symptomatic hydrocephalus; 25/84 (29.8%) patients required a CSF diversion procedure in the postoperative period. Children presenting with symptom duration of less than 3 months had a significantly higher requirement for postoperative CSF diversion in comparison to those with longer symptomatology (p = 0.016). Evan's index and frontal and occipital horn ratio on preoperative imaging were found to correlate closely with the need for postoperative shunt (p = 0.001 and p < 0.001, respectively). The requirement for shunt was statistically higher in patients with midline tumors in comparison to laterally placed lesions (p = 0.04) and in children with medulloblastoma (p < 0.001) and ependymoma (p = 0.016) as the tumor subtypes. Children who underwent intraoperative external ventricular drainage (EVD) had a shunt insertion rate of 39.6% compared with 16.7% of those who did not have an EVD (p < 0.001). Patients with meningitis and pseudomeningocele in the postoperative period had a statistically significant higher risk of shunt requirement (p = 0.008 and p = 0.016, respectively). The mean age at diagnosis and the extent of tumor resection did not correlate with the need for CSF diversion. CONCLUSION: The fact that less than one-third of patients require a CSF diversion after posterior fossa tumor resection refutes the role of prophylactic endoscopic third ventriculostomy. Awareness regarding the factors that can predict persistent postoperative hydrocephalus is essential for the surgeon during patient counseling and surgical planning, and also in deciding the intensity of postoperative clinical and radiological monitoring.

A colorimetric hydroxy naphthol blue based loop-mediated isothermal amplification detection assay targeting the ß-tubulin locus of Sarocladium oryzae infecting rice seed.

Sarocladium oryzae is a widely prevalent seed-borne pathogen of rice. The development of a rapid and on-site detection method for S. oryzae is therefore important to ensure the health of rice seeds. Loop-mediated isothermal amplification (LAMP) is ideal for field-level diagnosis since it offers quick, high-specific amplification of target template sequences at a single temperature. We designed primers based on the ß-tubulin region of S. oryzae. The LAMP technique devised was extremely sensitive, detecting the presence of the S. oryzae template at concentrations as low as 10 fg in 30 minutes at 65°C. The assay specificity was confirmed by performing the experiment with genomic DNA isolated from 22 different phytopathogens. Through the addition of hydroxy naphthol blue in the reaction process prior to amplification, a colour shift from violet to deep sky blue was seen in the vicinity of the target pathogen only. Finally, the LAMP assay was validated using live infected tissues, weeds and different varieties of seeds collected from different locations in Tamil Nadu, India. If developed into a detection kit, the LAMP assay developed in this study has potential applications in seed health laboratories, plant quarantine stations, and on-site diagnosis of S. oryzae in seeds and plants.

Serum TSH Level as a Simple Efficient Tool to Assess the Risk of Thyroid Malignancy in Euthyroid Patients with Indeterminate Cytology - A Cohort Study.

Context: A significant number of fine-needle aspiration cytology (FNAC) for thyroid nodules is reported as indeterminate. Expensive molecular testing can give a clue to the possibility of malignancy in this group. The effectiveness of serum thyroid-stimulating hormone (TSH) levels as a diagnostic tool in euthyroid patients with indeterminate cytology has not been previously studied, especially in the Indian population. Aims: This study was conducted to evaluate the predictive efficacy of serum TSH in the early diagnosis and treatment of malignancy. Settings and Design: This is a retrospective cross-sectional study on a cohort of patients who presented to our department with complaints of thyroid swelling and underwent thyroidectomy. Methods and Material: Euthyroid patients who underwent thyroid surgery for newly diagnosed thyroid nodules with FNAC reported as indeterminate cytology were included in our study. Based on the histopathological report, the patients were divided into two groups and into quartiles based on TSH values. Statistical Analysis Used: The mean difference in the numerical variables between groups was compared using the independent two-sample 't' test for parametric data and Mann-Whitney 'u' test for non-parametric data. A logistic regression analysis was done with age, sex, TSH level and nodule size as dependant variables and malignancy as the independent variable. Results: There were 211 patients in group A and 93 in group B. Patients with malignancy confirmed on final histopathology showed higher serum TSH levels compared to benign nodules (2.93 ± 1.067 vs 1.73 ± 1.051, P = <0.001). The mean TSH levels of all types of malignant nodules correlated with our test model (>2.185 mIU/L). Conclusions: Serum TSH above 2.185 mIU/mL is a good predictor of malignancy in indeterminate nodules. It is an inexpensive, safe and reliable diagnostic screening test for the risk of malignancy in an indeterminate nodule.

Iophendylate myelography induced thoracic arachnoiditis, arachnoid cyst and syrinx, four decades later.

Iophendylate (Myodil) was a popular oil-based contrast agent used until late 1980s for myelography, ventriculography and cisternography. Although several long-term sequelae have been reported in literature, they are extremely rare. We report a rare occurrence of symptomatic dorsal arachnoid cyst 40 years after Myodil myelography.

Choroid plexus tumors: an institutional series of 25 patients.

PURPOSE: Choroid plexus tumors (CPT) are rare neoplasms that pose considerable treatment challenges. This study reviews a single institute's experience with 25 patients of CPT and attempts to contribute to the general body of knowledge on CPT. MATERIALS AND METHODS: A retrospective analysis of the case records of 25 patients operated for CPT since January 1998 and having a minimum of 1 year follow-up. RESULTS: The study group included 12 (48%) cases of choroid plexus papilloma (CPP), 09 (36%) cases of choroid plexus carcinoma (CPC) and 4 cases of atypical CPP. The mean age at presentation was 18.6 years (range, 6 months to 54 years; SD, 18.7) and a male preponderance was noted (17:8). Raised intracranial pressure was the commonest presenting symptom (72%). The tumors were distributed as follows: lateral ventricle (16; 64%), fourth ventricle (5; 20%), fourth ventricle with cerebellopontine angle extension (3; 12%), and third ventricle (1; 4%). A complete surgical excision was achieved in 11 cases of CPP and 8 cases of CPC. Operative complications include pneumocephalus (40%), focal deficits (36%), subdural effusion (32%), and persistent hydrocephalus requiring shunt (24%). All patients with CPP had a good outcome at the end of a mean follow-up of 5.4 years, whereas the median survival for patients with CPCs who underwent a subtotal resection with adjuvant therapy was 36 months. CONCLUSION: CPTs include a spectra ranging from CPP to CPC. Radiologic and histologic characterization of these tumors is difficult and newer immunohistochemical and genetic studies should be done to differentiate them from each other. Total excision offers a good prognosis and should be attempted for all forms of CPTs. CPPs carry a good prognosis, and adjuvant therapy is not indicated even after partial excision. CPCs and atypical CPCs carry a poor prognosis, and adjuvant therapy improves survival marginally after total excision. Spinal drop metastases are common for CPC and screening of the spine for possible metastasis should be part of the routine preoperative and postoperative investigation protocol.

Intracranial intradural aneurysmal bone cyst: a unique case.

Aneurysmal bone cyst (ABC) of the skull is exceedingly rare. We report a unique case of an intradural ABC without bone involvement presenting with raised intracranial pressure. The patient was a 14-year-old boy who presented with headache, vomiting and right focal seizure. Imaging showed a large multicystic left frontal lesion without any evidence of bone involvement. The lesion adherent to an intact sphenoid wing dura was completely excised. The histopathology report was consistent with an ABC. This case represents the first report of an ABC without involvement of the skull bones or any evidence of dural erosion. The possible mechanism of origin at this unusual location is hypothesized.

Aneurysm of the anterior inferior cerebellar artery-posterior inferior cerebellar artery variant: two case reports and review of literature.

Aneurysms arising from anterior inferior cerebellar artery-posterior inferior cerebellar artery (AICA-PICA) variant are exceedingly rare. We report two cases of distal AICA-PICA variant aneurysms and discuss their surgical management with emphasis on the higher risk for perforator artery injury. The etiopathogenesis of these rare aneurysms at non-branching sites remains elusive.

Preoperative Preparation of Hyperthyroidism for Thyroidectomy - Role of Supersaturated Iodine and Lithium Carbonate.

INTRODUCTION: Thyroidectomy is effective and safe procedure for permanent cure of hyperthyroidism (HT). Iodine preparations are widely used before operation to prevent excess blood loss. Ideal regimen for refractory HT is debated. This retrospective case-control study is designed to study the efficacy of various regimens of preoperative preparations. MATERIALS AND METHODS: Case records, anesthesia charts, and follow-up details of hyperthyroid patients undergoing thyroidectomy were reviewed and compared with an age- and sex-matched euthyroid patients operated during the same period. Iodine preparations were not used for preoperative preparation. Study group was subdivided based on preoperative regimens of anti-thyroid medications. RESULTS: Of the 168 patients in the study group, procedure time, duration of hospital stay, and overall complication rate were high compared to euthyroid group. Operative blood loss was not high in the study group. There was no difference in rate of complications in the subgroups of the study cohort. CONCLUSION: Iodine preparations are not mandatory in preoperative preparation of HT. Lithium carbonate is effective in preoperative preparation of refractory HT. Rate of postthyroidectomy complications is not different in patients receiving thionamides alone or in combination with ß-blocker.

Interhemispheric transcallosal transforaminal approach and its variants to colloid cyst of third ventricle: Technical issues based on a single institutional experience of 297 cases.

CONTEXT: Colloid cysts are benign intracranial lesions that usually involve the anterior third ventricle with varying appearance on imaging studies. The number of articles debating the origin of this tumor is surpassed by papers proposing the best modality available for its treatment. AIM: The purpose of this study is to analyze the clinical presentation and surgical outcome of colloid cysts surgically managed over a period of thirty-two years and evaluate the technical issues based on our experience. STUDY DESIGN: This is a retrospective case series study. MATERIALS AND METHODS: This is a retrospective case series study on 297 consecutive patients with colloid cysts who were operated. The case records of all the patients were evaluated to record the clinical symptoms and signs, imaging findings, surgical procedure, complications and follow-up data. RESULTS: There were 178 (60%) males and 119 (40%) females, their age ranging from 9 to 66 years with a mean age of 28 years. The mean duration of symptoms was 1.8 months. Raised intracranial pressure headache was the most common initial presenting symptom followed by visual blurring, memory disturbance and drop attacks with gait unsteadiness. The tumor was an incidental imaging finding in five patients (2%). While an interhemispheric transcallosal approach was used in 275 (92.6%) patients, it was trans-cortical in 22 (7.4%). Twenty-two patients required emergency surgery in view of worsening sensorium. Postoperative complications included memory impairment, limb weakness and seizures. Despite documented complete excision of the tumor in 6 cases, 8 patients had recurrence of tumor during follow-up. CONCLUSION: Colloid cysts are potential life threatening but benign lesions that can be removed safely with low morbidity and mortality through the interhemispheric transcallosal approach and its variants. The possibility for recurrence warrants, close imaging follow-up after surgery. It is essential for neurosurgeons to be familiar with the different transcallosal approaches to reach the third ventricle especially for a posteriorly situated cyst and a narrow foramen of Munro.

A Combinatorial effect of carboxymethyl cellulose based scaffold and microRNA-15b on osteoblast differentiation.

The present study was aimed to synthesize and characterize a bio-composite scaffold containing carboxymethyl cellulose (CMC), zinc doped nano-hydroxyapatite (Zn-nHAp) and ascorbic acid (AC) for bone tissue engineering applications. The fabricated bio-composite scaffold was characterized by SEM, FT-IR and XRD analyses. The ability of scaffold along with a bioactive molecule, microRNA-15b (miR-15b) for osteo-differentiation at cellular and molecular levels was determined using mouse mesenchymal stem cells (mMSCs). miR-15b acts as posttranscriptional gene regulator and regulates osteoblast differentiation. The scaffold and miR-15b were able to promote osteoblast differentiation; when these treatments were combined together on mMSCs, there was an additive effect on promotion of osteoblast differentiation. Thus, it appears that the combination of CMC/Zn-nHAp/AC scaffold with miR-15b would provide more efficient strategy for treating bone related defects and bone regeneration.