Targeted Next Generation Sequencing (tNGS) for detection of drug-resistant tuberculous meningitis: Is this sequencing technology ready for prime time?

PURPOSE: Tuberculous meningitis (TBM) is the most severe form of tuberculosis (TB). Difficulty in diagnosing the condition along with other factors, increases its potential for high morbidity and mortality. Targeted Next Generation Sequencing (tNGS) generates high quality sequence read depths, enabling the identification of low-frequency alleles linked to Drug resistance (DR). The paucibacillary nature of tuberculous meningitis is a challenge for making a definitive diagnosis. METHODS: tNGS was performed on 20 cerebrospinal fluid (CSF) samples where, MGIT has shown Positive MTB Cultures. We simultaneously performed pyrosequencing (PSQ) and phenotypic Drug susceptibility testing (pDST) for these 20 samples. RESULTS: Sequencing results (from tNGS and PSQ) were compared with reference standards i.e. pDST. tNGS detected MTB in 7/20 (35%) CSF samples whereas, PSQ detected MTB in 17/20 (85%). CONCLUSION: Although tNGS has ability to detect minority variants along with detection of additional targets than PSQ, PSQ remains the diagnostic choice in our tertiary lab.

Collagen concentration regulates neutrophil extravasation and migration in response to infection in an endothelium dependent manner.

Introduction: As the body's first line of defense against disease and infection, neutrophils must efficiently navigate to sites of inflammation; however, neutrophil dysregulation contributes to the pathogenesis of numerous diseases that leave people susceptible to infections. Many of these diseases are also associated with changes to the protein composition of the extracellular matrix. While it is known that neutrophils and endothelial cells, which play a key role in neutrophil activation, are sensitive to the mechanical and structural properties of the extracellular matrix, our understanding of how protein composition in the matrix affects the neutrophil response to infection is incomplete. Methods: To investigate the effects of extracellular matrix composition on the neutrophil response to infection, we used an infection-on-a-chip microfluidic device that replicates a portion of a blood vessel endothelium surrounded by a model extracellular matrix. Model blood vessels were fabricated by seeding human umbilical vein endothelial cells on 2, 4, or 6 mg/mL type I collagen hydrogels. Primary human neutrophils were loaded into the endothelial lumens and stimulated by adding the bacterial pathogen Pseudomonas aeruginosa to the surrounding matrix. Results: Collagen concentration did not affect the cell density or barrier function of the endothelial lumens. Upon infectious challenge, we found greater neutrophil extravasation into the 4 mg/mL collagen gels compared to the 6 mg/mL collagen gels. We further found that extravasated neutrophils had the highest migration speed and distance in 2mg/mL gels and that these values decreased with increasing collagen concentration. However, these phenomena were not observed in the absence of an endothelial lumen. Lastly, no differences in the percent of extravasated neutrophils producing reactive oxygen species were observed across the various collagen concentrations. Discussion: Our study suggests that neutrophil extravasation and migration in response to an infectious challenge are regulated by collagen concentration in an endothelial cell-dependent manner. The results demonstrate how the mechanical and structural aspects of the tissue microenvironment affect the neutrophil response to infection. Additionally, these findings underscore the importance of developing and using microphysiological systems for studying the regulatory factors that govern the neutrophil response.

Evaluating the safety and effectiveness of direct oral anticoagulants compared with warfarin in very elderly patients with atrial fibrillation with and without low bodyweight.

BACKGROUND: Limited data exist on the safety and effectiveness of using direct oral anticoagulants (DOACs) in patients with atrial fibrillation aged 80 years or more with and without low bodyweight (LBW). OBJECTIVES: We aimed to evaluate the safety and effectiveness of using DOACs in this population compared with warfarin. METHODS: This retrospective active comparator new-user cohort study included veteran patients with atrial fibrillation who were newly initiated on either warfarin or DOACs between January 1, 2015, and January 1, 2021. The primary outcome was incidence of major bleeding and ischemic stroke. All outcomes were compared between treatment groups in 2 propensity score-matched cohorts of patients aged 80 years older with (AW) and without LBW (age-only cohort). Cox proportional hazard models were used to estimate adjusted hazard ratios (aHRs). RESULTS: Matched AW and age-only cohorts included 493 and 11 909 patients, respectively, in each of the DOAC and warfarin exposure groups. Greater than 90% were male, with a mean age of ∼87 years. The rate of major bleeding was lower in the DOAC group compared with warfarin in both the AW (aHR, 0.63; 95% CI, 0.46-0.87) and age-only cohorts (aHR, 0.58; 95% CI, 0.49-0.77). A significantly lower rate of ischemic stroke occurred in the DOAC group compared with warfarin in the AW cohort (aHR, 0.62; 95% CI, 0.45-0.84) and age-only cohort (aHR, 0.63; 95% CI, 0.58-0.68). CONCLUSION: DOAC use was associated with lower risk of major bleeding and ischemic stroke compared with warfarin in patients aged 80 years or older with and without LBW.

Evaluation of Neuropsychiatric outcomes in patients hospitalized with COVID-19 in a nationwide Veterans Health Administration cohort.

Hospitalized patients with COVID-19 have an increased risk of developing psychiatric symptoms associated with post-COVID-19 syndrome. We aimed to evaluate the impact of COVID-19 hospitalization on neuropsychiatric healthcare utilization as well as new-onset depression and dementia. This nationwide, retrospective, observational cohort study included hospitalized COVID-19 patients aged 18 years or older across the Veterans Health Administration database from January 1st, 2020 through January 1st, 2022. The COVID-19 group consisted of patients hospitalized with COVID-19 with a positive test within seven days of the hospitalization. The control group consisted of patients hospitalized for reasons other than COVID-19 without a prior positive test or during the study duration. Propensity scores were utilized for 1:1 matching. This study included 50,805 patients in each matched cohort. Average patient population was 69 years old with ∼93 % male. The primary outcome of psychiatry-related hospitalization incidence rates were significantly higher in the COVID-19 group at both 90 days and 180 days. There was also a significant increase in the incidence outpatient mental health visits at 180 days in the COVID-19 cohort. Significantly higher risk of new-onset depression and new-onset dementia in the COVID-19 hospitalization group at 180 days as compared to the non-COVID-19 cohort was noted.

Evaluating the Safety of Sodium-Glucose Cotransporter-2 Inhibitors in a Nationwide Veterans Health Administration Observational Cohort Study.

Sodium-glucose cotransporter-2 inhibitors (SGLT-2is) are indicated in patients with or without type 2 diabetes mellitus atherosclerotic cardiovascular disease, chronic kidney disease, or heart failure. Postmarket surveillance data have identified many safety signals which warrants further investigation. We aimed to compare the safety of SGLT-2i and glucagon-like peptide-1 receptor agonists (GLP-1RA). Using the Veterans Health Administration nationwide database, patients with type 2 diabetes mellitus who were newly initiated on a SGLT-2i or GLP-1RA between April 1, 2013 and September 1, 2020 were identified. The primary outcome was the incidence of any amputation, below-knee amputation (BKA), all clinical fractures, hip fracture, Fournier gangrene, acute pancreatitis, diabetic ketoacidosis (DKA), serious urinary tract infections (UTIs), and venous thromboembolism (VTE). All outcomes were compared between the treatment groups. Cox proportional hazard models were used to estimate adjusted hazard ratios (aHRs) for the comparative analysis. A total of 70,694 propensity-matched new users of SGLT-2i and GLP-1RA were identified. The use of SGLT-2 inhibitors, compared with GLP-1RA, was not associated with an increased rate of any amputation (aHR 1.02, 95% confidence interval [CI] 0.82 to 1.27), BKA (aHR 1.05, 95% CI 0.84 to 1.32), all clinical fractures (aHR 0.94, 95% CI 0.86 to 1.03), hip fractures (aHR 0.82, 95% CI 0.50 to 1.32), DKA (aHR 1.66, 95% CI 0.97 to 2.85), VTE (aHR 1.02, 95% CI 0.80 to 1.30), acute pancreatitis (aHR 1.02, 95% CI 0.80 to 1.30), and Fournier gangrene (aHR 0.92 95% CI 0.61 to 1.38). Lower rates of serious UTIs were observed in the SGLT-2i group than in the GLP-1RA group (aHR 0.74, 95% CI 0.64 to 0.84). This real-world study found that SGLT-2i use compared with GLP-1RA did not increase the rate of amputation, BKA, clinical fractures, hip fracture, Fournier gangrene, acute pancreatitis, DKA, serious UTIs, and VTE in veteran patients.

Evaluating the Association of Montelukast Use on Neuropsychiatry-Related Healthcare Utilization and Depression in COVID-19-Hospitalized Veterans: A Nationwide VA Observational Cohort Study.

BACKGROUND: Montelukast's new boxed warning for neuropsychiatric events questions its use in the setting of coronavirus disease 2019 (COVID-19) due to increased risk for new-onset psychiatric diagnoses. OBJECTIVE: We aim to evaluate the impact of using montelukast in patients hospitalized with COVID-19 on neuropsychiatry-related healthcare utilization and depression. METHODS: This retrospective nationwide observational cohort study using the Veterans Health Administration database included patients from January 1, 2020, through July 1, 2021. The treatment cohorts consisted of patients with and without montelukast use prior to COVID-19 hospitalization and matched using propensity score (PS) to two control cohorts: patients with COVID-19-related hospitalization without prior montelukast use and patients with prior montelukast use who were hospitalized for reasons other than COVID-19. The primary outcome of psychiatric hospitalizations at 90 days and 180 days and mental health visits at 180 days were compared using Poisson or negative binomial regression. Secondary outcomes of new-onset depression and new use of antidepressants were analyzed using multivariable logistic regression. RESULTS: After PS matching, a total of 415 patients were included in COVID-19 with and without montelukast matched cohort and 409 patients in montelukast with and without COVID-19-related hospitalization matched cohorts. For the primary outcomes, inpatient psychiatric hospitalization at 90 days [incidence rate ratio (IRR) 95% CI 1.79 (1.36-2.36)] and 180 days [IRR 95% CI 1.79 (1.32-2.25)] and mental health visits at 180 days [IRR 95% CI 1.72 (1.45-2.03)] were significantly higher in the montelukast with COVID-19 hospitalization group compared with those hospitalized without COVID-19. No difference in primary outcomes were noted in patients hospitalized with COVID-19 with and without use of montelukast. No significant difference was found in the secondary outcomes between either comparator group. CONCLUSIONS: Patients with prior montelukast use who were hospitalized with COVID-19 appeared to have increased rate of neuropsychiatry-related healthcare utilization.

A Quasi-Experimental Evaluation of Single Trough-Based Area Under the Curve Guided Dosing on the Incidence of Vancomycin Associated Nephrotoxicity in Veteran Patients.

Background: Two common dosing strategies for vancomycin are trough-based and area under the curve (AUC)-based dosing. Objective: To compare the incidence of nephrotoxicity in trough-based dosing group with the single trough-based AUC dosing at the Salem VA Medical Center. Methods: This retrospective study included patients who received trough-based dosing of vancomycin between January 1, 2017, and January 1, 2019 (preimplementation group) and AUC-based dosing (postimplementation) between October 1, 2019, and October 1, 2021, at the Salem VA Medical Center. The primary outcome was nephrotoxicity at 96 hours, 7 days, and entire hospital length of stay (LOS). Secondary outcomes included 30-day readmission and all-cause mortality rates, cumulative doses at 24, 48, and 72 hours, and percentage of patients considered at goal (AUC 400-600 or trough between 10 and 20 mg/L). Propensity score (PS) matching was utilized to adjust for confounding. Results: After PS matching 100 patients were included in preimplementation and 95 patients in the postimplementation group. The average study patient was a 68-year-old white male. There was significant reduction in the risk of nephrotoxicity in postimplementation cohort at 96 hours (adjusted (a)HR: 0.28, 95% CI (0.12-0.66); 7 days (aHR: 0.39, 95% CI (0.18-0.85); and entire hospital LOS (aHR: 0.46, 95% CI (0.22-0.95). Secondary outcomes showed no difference between the groups except significantly higher proportion of patients were considered at therapeutic goal in the postimplementation cohort compared with pre-implementation cohort. Conclusion: This hypothesis generating study shows that AUC-based dosing calculated using single trough concentration may result in reduced rate of nephrotoxicity than trough-based dosing.

CHAnges in Diuretic Medication Prescribing and Surrogate Laboratory Parameters After Initiating EmpagliflOziN in Veterans (CHAMPION Cohort Study).

BACKGROUND AND OBJECTIVES: Sodium-glucose cotransporter type 2 inhibitors have evolved into a novel drug class utilized for reductions in cardiovascular risk and heart failure hospitalization. We aimed to describe the impact of sodium-glucose cotransporter type 2 inhibitors on diuretic prescribing patterns and intermediate laboratory outcomes in patients with and without diuretic use. METHODS: This retrospective cohort study included patients taking empagliflozin as of 1 July, 2021. Patients were assigned to the intervention group if prescribed a diuretic concomitantly or a control group otherwise. The primary outcome was the impact of empagliflozin on diuretic prescribing (i.e., no change, discontinuation, decrease, increase). Secondary outcomes were change in weight, hemoglobin A1c, estimated glomerular filtration rate, hemoglobin, hematocrit, blood pressure, and electrolytes at 90 and 180 days. Mean differences were compared using the t-test between groups or the paired t-test within groups. Patients without diuretic use were matched 1:1 to patients taking diuretics using propensity scores. RESULTS: This study included 1189 patients: 750 in the control group and 439 in the intervention group. After propensity score matching, baseline characteristics were well balanced. Of the 439 patients in the intervention group, 118 had changes in the diuretic regimen. There were 131 changes: 109 (83.2%) discontinuations, 13 (9.92%) decreases, and nine (6.87%) increases. The mean furosemide equivalent loop dose was reduced after empagliflozin initiation (50.62 mg vs 43.13 mg; p < 0.001). Among all patients, there was a decrease in weight (p = 0.01), estimated glomerular filtration rate (p < 0.001), and hemoglobin A1c (p < 0.001). There was an increase in hemoglobin (p < 0.001), hematocrit (p < 0.001), and magnesium (p < 0.001). In the propensity score-matched cohort, there was a significant reduction from baseline in mean weight in the intervention group compared with the control group (p < 0.001). CONCLUSIONS: This hypothesis-generating study suggests that sodium-glucose cotransporter type 2 inhibitors may lower diuretic requirements, further supported by a reduction in weight in the intervention cohort.

Impact of Pharmacist-Led Heart Failure Clinic on Optimization of Guideline-Directed Medical Therapy (PHARM-HF).

This prospective study included patients with heart failure (HF) with reduced ejection fraction (HFrEF) with LVEF < = 40% to evaluate the impact of pharmacist on guideline directed medical therapy (GDMT). The primary outcome was to compare proportion of triple GDMT achieved for Angiotensin-Converting-Enzyme-Inhibitors (ACEI)/Angiotensin-Receptor-Blockers (ARB)/Angiotensin-Receptor-Neprilysin-Inhibitors (ARNI), beta-blockers, aldosterone antagonists (AA), and quadruple GDMT which in additional to triple therapy, included Sodium glucose co-transporter 2 inhibitor (SGLT2i) at 90-day post-enrollment compared to baseline. Secondary endpoints included achieving target and/or maximally tolerated ACEI/ARB/ARNI and beta-blockers combined and individually as well as SGLT2i and AA GDMT at 90-day post-enrollment compared to baseline. We also compared combined and individual HF-related hospitalization/emergency room (ER) visits 90 days pre-/post-enrollment. Of the total 974 patients screened, 80 patients seen at least once in the heart failure medication titration clinic (HMTC) were included in the analysis. Median (IQR) age was 71 (57-69) years with majority white male. There was a significant improvement in the proportion of patients who achieved quadruple GDMT (p = 0.001) and triple GDMT (p-value = 0.020) at 90-day post-enrollment compared to baseline. The secondary GDMT outcomes were also significantly increased at 90 days post-enrollment compared to baseline. Significant difference in mean as well as proportion of combined HF-related hospitalization/ER-visits was found 90 days pre-/post-enrollment (p = 0.047). Our study found that pharmacist's intervention increased the proportion of patients who achieved GDMT at 90 days.

Risk of new-onset osteoporosis in single-center veteran population receiving direct oral anticoagulants versus warfarin.

BACKGROUND: Oral anticoagulants (OAC) have shown to affect bone mineral density and cause osteoporosis. Limited studies have investigated the relationship between its use and risk of osteoporosis. We aim to compare the risk of osteoporosis in patients on warfarin versus direct oral anticoagulants (DOACs). METHODS: A retrospective single-center cohort study was conducted in veterans age > 18 years of age in whom warfarin or DOACs were newly initiated between January 1st, 2012 to April 1st, 2020 at Salem VA Medical Center. Patients on OAC for at least 90 days qualified for inclusion and excluded if they were pregnant or had history of mechanical valve and mitral stenosis, on edoxaban or had previous history of osteoporosis or use of antiosteoporosis medication. Primary outcome was comparing incidence of new-onset osteoporosis between warfarin and DOACs. Secondary outcomes included comparing incidence of all clinical fractures, hip fractures, major bleeding and intracranial bleed between the treatments. Cox proportional hazard ratios (HRs) and 95% confidence intervals (CI) comparing the two treatment groups were calculated. RESULTS: A total of 1526 patients on DOAC and 1121 in warfarin group were included in the study. After propensity-score (PS) matching, 943 patients were included in each arm. Baseline characteristics were similar after PS-matching. DOAC treatment was associated with lower incidence of new-onset osteoporosis as compared to warfarin in matched cohort (aHR: 0.19, 95% CI: 0.10-0.36; p < 0.0001). The risk of all clinical fracture and hip fracture was similar in patients receiving DOACs as versus warfarin (aHR: 1.18, 95% CI: 0.82-1.69; p = 0.3671). DOAC use was associated with lower risk of major bleed (aHR: 0.07, 95% CI: 0.03-0.15; p < 0.0001) and intracranial bleed (aHR: 0.14, 95% CI: 0.03-0.64; p = 0.0111). CONCLUSION: Overall, as compared to warfarin, prolonged use of DOACs is associated with lower risk of new-onset osteoporosis. We hope that our study findings will enlighten current clinical practices assuring safe use of OAC in veteran patients.

Proton Pump Inhibitor Utilization in Veteran Patients on Combined Antithrombotic Therapy and Validation of Simplified Bleeding Risk Score.

BACKGROUND: Concomitant use of anticoagulant and antiplatelet agents can increase the risk of gastrointestinal bleed (GIB). Use of proton pump inhibitors (PPIs) has been proposed to decrease the risk of GIB in patients on combined antithrombotic therapy (CAT). OBJECTIVE: To describe the current utilization of PPIs in veteran patients on CAT and associated clinical predictors of GIB. METHODS: This retrospective study included patients on CAT receiving PPIs, with at least one of the CAT agents initiated between January 1, 2018 and October 30, 2018. Data were extracted from the computerized patient record system. Primary end point included estimating proportion of patients on CAT receiving PPI co-therapy, describing patient characteristics, and identifying clinical predictors of GIB. Secondary outcomes included reporting GIB events and all-cause mortality. Additional outcome was to validate the five-factor risk score (FFRS) for GIB in patients on CAT and compare its overall predictive performance to HAS-BLED score. RESULTS: This study reports an overall rate of PPI co-therapy in patients on CAT of 40.9% (484/1181), with only 22.3% of patients on CAT receiving PPI for GIB prophylaxis. There was no difference in the mean follow up duration of PPI users and PPI co-therapy (264.01 vs 271.92 days; p=0.3761). Current alcohol use (p=0.005), current smokers (p=0.022), chronic kidney disease (p=0.004), peptic ulcer disease (p<0.001), and non-steroidal anti-inflammatory drug use (p=0.048) were significant predictors of GIB in multivariate analyses of our study cohort. We further provide exploratory validation that use of a simplified FFRS to predict GIB showed a trend towards better overall predictive performance as compared to HAS-BLED score (C-statistic: 0.738; 95% CI 0.684-0.787 for FFRS vs C-statistic: 0.596; 95% CI 0.538-0.653 for HAS-BLED; p=0.0094). CONCLUSION: This study reports lower rate of PPI co-therapy in veteran patients on CAT per currently available guidance. Further we explore utilization of simplified FFRS model to predict GIB in patients on CAT with long-term PPI co-therapy.

A rare case report of apixaban-induced lichenoid eruption.

With recent increase in the use of direct oral anticoagulants (DOACs), several new cases of adverse drug reactions (ADRs) have been identified in pharmacovigilance surveys. These ADRs can result in significant mortality and morbidity if not identified and treated promptly. It is important for physicians to recognize that immunologically mediated delayed hypersensitivity reactions, although rare in occurrence, can have significant impact on patient's quality of life. To the best of our knowledge, we report the first case of lichenoid eruption associated with apixaban. We further provide evidence of tolerance to rivaroxaban in the same patient. PLAIN LANGUAGE SUMMARY: Apixaban-induced lichenoid eruption Well documented case reports, although providing evidence of probable causal relationship between a drug and specific adverse drug reactions (ADRs), can increase awareness amongst clinicians treating patients with direct oral anticoagulants (DOACs), especially with its rapid utilization. Rare ADRs are difficult to detect as clinical trials of DOACs lacked enough patient sample, making post-marketing reporting of such events important so both patients and clinicians can be vigilant to help with prompt recognition of such symptoms. We report the first case of lichenoid eruption hypersensitivity reaction associated with apixaban in patient with tolerance to rivaroxaban.

A single center retrospective cohort study evaluating use of direct oral anticoagulants (DOACs) in morbidly obese veteran population.

BACKGROUND: Direct oral anticoagulants (DOACs) are preferred over warfarin for the treatment of venous thromboembolism (VTE) as well as atrial fibrillation (AF). The efficacy and safety of fixed dose regimen of DOACs remains unclear in morbidly obese patient population and are currently not recommended for use in patients with a body mass index (BMI) > 40 kg/m2 or a weight of >120 kg. OBJECTIVE: The goal of this study is to evaluate the use of DOACs in morbidly obese veteran population as compared to warfarin. METHODS: This retrospective single center cohort study included morbidly obese patients weighing >120 kg or BMI > 40 kg/m2 who were prescribed DOACs or warfarin for AF or VTE between January 1st, 2015 to May 31st, 2018. Data was extracted from the computerized patient record system (CPRS) and the Salem Veterans Affairs Medical Center (SVAMC) data warehouse. The primary outcome was combined incidence of stroke/transient ischemic attack (TIA) and VTE. Secondary outcomes included all-cause mortality, ISTH major bleed and clinically relevant non major bleed as well as primary outcome and ISTH major bleeding analyses in the subgroups of AF and VTE patients. RESULTS: The study included 190 patients in warfarin group and 214 in DOACs group. Baseline characteristics were mostly well matched except for the follow up duration which was significantly longer in the warfarin group as compared to DOAC (p > 0.001). The annual incidence rate of primary outcome was similar between warfarin and DOACs (3.91% vs.1.61%; RR:2.436; 95% CI 0.85-8.54; p = 0.1543). CONCLUSION: This hypothesis generating study suggests that DOAC use may be feasible in morbidly obese patients. Additional studies are necessary to confirm this finding and further guide clinical practice in this area.

A Case Report of Rivaroxaban-Induced Urticaria and Angioedema With Possible Cross-Reaction to Dabigatran.

Anticoagulants are commonly associated with hemorrhagic complications. However, rare hypersensitivity drug reactions associated with direct oral anticoagulants (DOACs) in form of cutaneous reactions such as urticaria as well as angioedema can have significant burden owing to increase in morbidity and mortality. Angioedema can be allergic, hereditary or idiopathic and can occur in isolation, in combination with urticaria as contributing component of anaphylaxis. With increase in the use of DOACs over warfarin as choice of anticoagulant in the treatment of atrial fibrillation (AF) as well as venous thromboembolism (VTE), recent post marketing surveillance has identified several reports of adverse drug reactions. This case report describes the clinical course of patient being treated for VTE, who experienced rivaroxaban-induced urticaria and angioedema. We further provide evidence for cross-reactivity to dabigatran manifested as significant cutaneous reaction. Patient was transitioned to warfarin with enoxaparin bridge and tolerated it well without any complications.

An experimental study to evaluate the antiosteoporotic effect of Panchatikta Ghrita in a steroid-induced osteoporosis rat model.

OBJECTIVE: The study was conducted to develop the glucocorticoid-induced osteoporosis (GIO) model in Sprague-Dawley weanling rats using different doses of methylprednisolone (MP) and evaluate the antiosteoporotic effect of a classical ayurvedic formulation, Panchatikta Ghrita (PG), in this model. MATERIALS AND METHODS: Institutional Animal Ethics Committee approval was obtained. Development of model was done by subcutaneous injection of 2 doses of MP (14 and 28 mg/kg/week) for 4 weeks in 21-day old weanlings. Following confirmation of the dose of MP that induced osteoporosis, the antiosteoporotic effect of PG was tested in this model in comparison to a known antiosteoporotic agent, alendronate. Both alendronate (2.9 mg/kg/day) and PG (1.35 g/kg/day) were administered orally 2 weeks after MP - 14 mg/kg/week injection and continued for 4 weeks. Serum and urine calcium and inorganic phosphate were analyzed at weekly intervals. Animals were sacrificed after 6 weeks, and femur bones were processed to measure bone hardness and elasticity and for histological studies. RESULTS: Rats treated with MP - 14 mg/kg/week showed optimum osteoporotic effect with no mortality as compared to MP - 28 mg/kg/week; hence, this dose of MP was used further for the efficacy study. Osteoporotic rats treated with PG 1.35 g/kg showed increase in serum calcium and inorganic phosphate levels, whereas urine calcium and phosphate levels were significantly reduced. A significant decrease in a number of osteoclasts, whereas an increase in bone hardness and elasticity was observed as compared to diseased group demonstrating antiosteoporotic effect of PG. CONCLUSION: PG has an antiosteoporotic effect in GIO rat model.

Nicotine behavioral pharmacology: clues from planarians.

BACKGROUND: Nicotine is one of the world's most addictive substances and the primary reason that humans inhale tobacco smoke. The pharmacological effects of nicotine can be investigated in planarians, aquatic flatworms that possess an integrated neural network including cephalic ganglia that some consider the earliest 'brain' and spinal cord. Here, we tested the hypothesis that nicotine exposure elicits mammalian-like behaviors in planarians. METHODS: Planarian motility and stereotypy (C-shape hyperkinesias) were quantified following acute nicotine exposure. During repeated nicotine exposure, we investigated the presence of withdrawal, tolerance, behavioral sensitization, and environmental place conditioning. RESULTS: Acute nicotine exposure increased stereotypical activity and elicited biphasic effects on motility. A low concentration (0.01 mM) increased motility whereas higher concentrations (0.3-10mM) elicited the opposite effect. Planarians exposed to nicotine (0.03 mM) for 60 min and then tested in water displayed reduced motility that was not observed during exposure to water, acute nicotine, or continuous nicotine. Nicotine-treated planarians withdrawn from the drug for 3 days before being challenged with nicotine displayed behavioral sensitization at low concentrations (0.1, 0.3mM) but tolerance at higher concentrations (1, 3mM). Planarians conditioned with nicotine in the ambient light (non-preferred environment) displayed a reduction in their natural preference for a dark environment. CONCLUSIONS: The present results suggest nicotine elicits mammalian-like effects in planarians, including decreased motility and increased stereotypy following acute administration and abstinence-induced withdrawal, behavioral sensitization, tolerance, and place conditioning during repeated exposure.

Topiramate antagonizes NMDA- and AMPA-induced seizure-like activity in planarians.

The mechanism of anticonvulsant action of topiramate includes inhibition of glutamate-activated ion channels. The evidence is most convincing for direct inhibitory action at the ionotropic AMPA (alpha-Amino-3-hydroxy-5-methylisoxazole-4-propionic acid) and kainate ((2S,3S,4S)-3-(Carboxymethyl)-4-prop-1-en-2-ylpyrrolidine-2-carboxylic acid) glutamate receptor subtypes. Less direct connection has been made to the NMDA (N-Methyl-d-aspartate) subtype. In the present study, we demonstrate that NMDA and AMPA produce concentration-dependent seizure-like activity in planarians, a type of flatworm which possesses mammalian-like neurotransmitters. In contrast, planarians exposed to the inhibitory amino acid, glycine, did not display pSLA. For combination experiments, topiramate significantly reduced planarian seizure-like activity (pSLA) produced by NMDA or AMPA. Additionally, NMDA-induced pSLA was antagonized by either an NMDA receptor antagonist (MK-801) or AMPA receptor antagonist (DNQX), thus suggesting that NMDA-induced pSLA was mediated by NMDA and non-NMDA receptors. The present results provide pharmacologic evidence of a functional inhibitory action of topiramate on glutamate receptor activity in invertebrates and provide a sensitive, quantifiable end-point for studying anti-seizure pharmacology.