Age-dependent pharmacokinetics and effect of roscovitine on Cdk5 and Erk1/2 in the rat brain.

Roscovitine is a cyclin-dependent kinase (Cdk) and signal-regulated kinase (Erk1/2) inhibitor that has been shown to be effective against several cancer types including brain tumors. We have shown previously that roscovitine crosses the blood brain barrier (BBB) and is rapidly eliminated from both plasma and brain in adult rats. However, age-dependent kinetics and its effects on the brain have not been reported. In the present study, we investigated the pharmacokinetics of roscovitine in adult and in 14 days old rats after the administration of a single dose of 25 mg/kg. Moreover, we studied the effect of the drug on Cdk5 and Erk1/2 activities in three brain regions, hippocampus, frontal cortex and cerebellum. The pharmacokinetics of roscovitine followed a two-compartment model in both plasma and brain in both adult and young rats. The terminal elimination half-life was 7 h in brain as well as in plasma in rat pups compared to < 0.5 h observed in adult rats. Brain exposure expressed as AUC brain/AUC plasma was 100% in rat pups compared to 20% found in adult rats. Roscovitine induced a significant Cdk5 inhibition and significant Erk1/2 activation in all studied pups brain regions at 2 h. This is the first study describing age-dependent pharmacokinetics of roscovitine and showing the high brain exposure of infant rats to the drug. Thus, roscovitine may be a promising candidate for the treatment of brain tumors in children

Dose-dependent effect and pharmacokinetics of fexinidazole and its metabolites in a mouse model of human African trypanosomiasis.

Human African trypanosomiasis (HAT) is a neglected tropical disease, with a population of 70 million at risk. Current treatment options are limited. In the search for new therapeutics, the repurposing of the broad-spectrum antiprotozoal drug fexinidazole has completed Phase III trials with the anticipation that it will be the first oral treatment for HAT. This study used the recently validated bioluminescence imaging model to assess the dose and rate of kill effect of fexinidazole in infected mice, and the dose-dependent effect of fexinidazole on trypanosome infection. Pharmacokinetics of fexinidazole in plasma and central nervous system (CNS) compartments were similar in both infected and uninfected mice. Drug distribution within the CNS was further examined by microdialysis, showing similar levels in the cortex and hippocampus. However, high variability in drug distribution and exposure was found between mice

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10&nbsp;years; 78.2% included were male with a median age of 37&nbsp;years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P &lt; 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Pharmacological and analytical studies of the cyclin dependent kinase inhibitors

Cyclin-dependent kinases (Cdks) play a key role in the regulation of cell cycle progression and RNA transcription. Deregulation of Cdks has been associated with several malignancies, neurodegenerative disorders, viral and protozoal infections, glomerulonephritis and inflammatory diseases. (R)-roscovitine (Rosco) is a synthetic tri-substituted purine that inhibits selectively Cdk1, 2, 5, 7 and 9. Rosco has shown promising cytotoxicity in cell lines and tumor xenografts. Rosco so far has only demonstrated modest antitumor activity in phase-II clinical trials, which is attributed mainly to the short elimination half-life and thus suboptimal exposure. Within the frame of the present thesis we aimed to investigate several aspects of the pharmacokinetics (PK) and pharmacodynamics (PD) of Rosco and two recently discovered analogues namely N-&-N1 and CR8. Our studies included bioanalysis, hematotoxicity, chrono-biodistribution, age dependent kinetics, PK and effect on Cdks. In vitro and in vivo studies of Rosco hematotoxicity were performed in Balb/c mice. Bone marrow cells were incubated with Rosco in semisolid methylcellulose media and assessed for their clonogenic capacity. Rosco inhibited the colony formation in cell type-, concentration- and exposure time-dependent manner. CFUGEMM were most sensitive, followed by BFU-E and the least sensitive progenitors were CFU-GM. In vivo studies showed low distribution of the drug to the bone marrow (AUCBM/AUCplasma 1.5%) and only transient inhibition of BFU-E formation was observed. These finding may explain the absence of myelosuppression in vivo. Age-dependent PK of Rosco were investigated in 14days rat pups and adult rats. Higher plasma and brain (22- and 100- fold, respectively) exposure was found in rat pups compared to adult rats. The elimination halflife in young rats was 7 hr compared to 30 min in adult rats. Brain exposure (AUC brain/AUC plasma) was 100% in rat pups compared to 20% found in adult rats. Moreover, transient Cdk5 inhibition and Erk1/2 activation was detected in brain of rat pups. The high brain exposure may indicate Rosco as s potential candidate for the treatment of brain tumors in children. The chronopharmacokinetics of Rosco was investigated in BDF1 male mice. Rosco was administered orally at ZT3 or at ZT19. We found that exposure to roscovitine was 38% higher and elimination half-life was 100% longer when dosing at ZT3 compared to ZT19. Moreover the tissue AUC/plasma AUC was higher at ZT3 in kidney, adipose, testis and lungs. The opposite was found in liver. In vitro microsomal assays indicated higher intrinsic clearance at ZT19. From these results, dosing times of roscovitine should be carefully considered in clinical trials. Analytical method for the detection of N-&-N1 and CR8 using high performance liquid chromatography with UV detection (HPLC-UV) were developed and validated. The PK of both drugs was investigated in Balb/c mice. N-&-N1 showed higher potency in tumor cell death induction compared to roscovitine; however, N-&N1 showed similar PK profile as roscovitine. CR8 has 100% oral bioavailability, longer elimination half-life, rapid and extensive biodistribution. Systemic exposure higher than IC50 reported for cell death in tumor cell lines was achievable for more than 10 hr. These two analogues displayed favorable pharmacological properties, and thus are good candidates for further in vivo studies. To conclude, these studies provide important knowledge about the PK, PD and PK/PD relationship of Rosco and its analogues. These studies may add more knowledge for treatment schedules and further preclinical and clinical development of Cdk inhibitors

The Role of Pharmacokinetics and Pharmacodynamics in Early Drug Development with reference to the Cyclin-dependent Kinase (Cdk) Inhibitor - Roscovitine

Pharmacokinetics, pharmacodynamics and pharmacogenetics play an important role in drug discovery and contribute to treatment success. This is an essential issue in cancer treatment due to its high toxicity. During the last decade, cyclin-dependent kinase inhibitors were recognised as a new class of compounds that was introduced for the treatment of several diseases including cancer. Cyclin-dependent kinases (Cdks) play a key role in the regulation of cell cycle progression and ribonucleic acid transcription. Deregulation of Cdks has been associated with several malignancies, neurodegenerative disorders, viral and protozoa infections, glomerulonephritis and inflammatory diseases. (R)-roscovitine is a synthetic tri-substituted purine that inhibits selectively Cdk1, 2, 5, 7 and 9. Roscovitine has shown promising cytotoxicity in cell lines and tumor xenografts. In this paper, we present several aspects of pharmacokinetics (PK) and pharmacodynamics (PD) of roscovitine. We present also some of our investigations including bioanalysis, haematotoxicity, age dependent kinetics, PK and effects on Cdks in the brain. Unfavourable kinetic parameters in combination with poor distribution to the bone marrow compartment could explain the absence of myelosuppression in vivo despite the efficacy in vitro. Higher plasma and brain exposure and longer elimination half-life found in rat pups compared to adult rats may indicate that roscovitine can be a potential candidate for the treatment of brain tumours in children. Cdk5 inhibition and Erk1/2 activation that was detected in brain of rat pups may suggest the use of roscovitine in neurodegenerative diseases. Early pharmacokinetic/pharmacodynamic studies are important issues in drug discovery and may affect further development of promising drug candidates

Comparative Study of Ambulatory Blood Pressure Monitoring and Clinic Blood Pressure Measurement in the Risk Assessment and Management of Hypertension

Objectives: Blood pressure (BP) measurements taken in a physician’s clinic do not represent readings throughout the day. Ambulatory blood pressure monitoring (ABPM) overcomes this problem by providing multiple readings with minimal interference with the patient’s daily activities. The purpose of our study was to evaluate the value of ABPM in risk assessment and management of hypertension compared to office measurements. Methods: A total of 104 consecutive hypertensive patients were retrospectively studied from January 2007 to December 2009. The following data were gathered: 1) clinic BP measurements; 2) routine blood test results; 3) electrocardiography, echocardiography, and 4) 24-hour ABPM. Results: The mean age of patients was 41.1 ± 8.6 years and 51.9% of them male. Indications for ABPM were: suspected “white coat” hypertension (10.6%), de novo hypertension (18.2%), resistant hypertension (27.9%) and others (43.3%). Mean daytime and nighttime BP were 134/82 and 124/73 mmHg respectively. A non-dipping pattern was reported in 64.4%. Echocardiographic evidence of left ventricular hypertrophy (LVH) and diastolic dysfunction (LVDD) was encountered in 22.1% and 29.8% respectively. ABPM parameters were significantly correlated with LVDD (P = 0.043). Patients with proved “white coat” hypertension did not receive antihypertensive therapy. Conclusion: Twenty-four hour ABPM is an important yet underused tool for proper risk stratification of treated hypertensive patients. The non-dipping profile is associated with a higher incidence of diastolic dysfunction. Our collective results revealed the superiority of ABPM over office BP measurement. Keywords: Hypertension; Blood pressure monitoring, ambulatory; Hypertrophy; Left Ventricular; Ventricular Dysfunction, Left

Diagnostic Value of Electrocardiographic T Wave Inversion in Lead aVL in Diagnosing Coronary Artery Disease in Patients with Chronic Stable Angina

Objectives: The clinical value of T wave inversion in lead aVL in diagnosing coronary artery disease (CAD) remains unclear. This study aims to investigate the correlation between aVL T wave inversion and CAD in patients with chronic stable angina.Methods: Electrocardiograms (ECGs) of 257 consecutive patients undergoing coronary angiography were analyzed. All patients had chronic stable angina. All patients with secondary T wave inversion had been excluded (66 patients). The remaining 191 patients constituted the study population. Detailed ECG interpretation and coronary angiographic findings were conducted by experienced cardiologists.Results: T wave inversion in aVL was identified in 89 ECGs (46.8%) with definite ischemic Q-ST-T changes in different leads in 97 ECGs (50.8%). Stand alone aVL T wave inversion was found in 27 ECGs (14.1%) while ischemic changes in other leads with normal aVL were identified in 36 ECGs (18.8%). The incidence of CAD was 86.3%. Single, two- and multi-vessel CAD were found in 38.8%, 28.5% and 32.7% of cases respectively. The prevalence of left main, left anterior descending, left circumflex and right coronary arteries were 4.7%, 61.2%, 29.3% and 44.5%, respectively. T wave inversion in aVL was found to be the only ECG variable significantly predicting mid segment left anterior descending artery (LAD) lesions (Odds Ratio 2.93, 95% Confidence Interval 1.59-5.37, p=0.001).Conclusion: This study provides new information relating to T wave inversion in lead aVL to mid segment LAD lesions. Implication of this simple finding may help in bedside diagnosis of CAD typically mid LAD lesions. However, further studies are needed to corroborate this finding

Effect of the Cdk-inhibitor roscovitine on mouse hematopoietic progenitors in vivo and in vitro.

Myelosuppression is one the most frequent side effects of chemotherapy. New agents that more selectively target cancer cells have been developed in attempt to improve the effects and to decrease the side effects of cancer treatment. Roscovitine is a purine analogue and cyclin-dependent kinase inhibitor. Several studies have shown its cytotoxic effect in cancer cell lines in vitro and in xenograft models in vivo. In this study, we investigated the effect of roscovitine on hematopoietic progenitors in vitro and in vivo in mice. The clonogenic capacity of hematopoietic progenitors was studied using burst-forming unit-erythroid (BFU-E), colony-forming unit granulocyte, macrophage (CFU-GM) and colony-forming unit granulocyte, erythroid, macrophage, megakaryocyte (CFU-GEMM). In vitro, bone marrow cells were exposed to roscovitine (25-250 microM) in Iscove's modified Dulbecco's media for 4 h or to roscovitine (1-100 microM) in MethoCult media for 12 days. No effect on colony formation was observed after exposure to roscovitine for 4 h; however, concentration- and cell type-dependent effects were observed after 12 days. Roscovitine in concentration of 100 microM inhibited the growth of all types of colonies, while lower concentrations have shown differential effect on hematopoietic progenitors. The most sensitive were CFU-GEMM, followed by BFU-E and then CFU-GM. In vivo, mice were treated with single dose of roscovitine (50, 100 or 250 mg/kg) and the effect on bone marrow was studied on day 1, 3, 6, 9 or 12 after the treatment. In the second part of experiment, the mice were treated with roscovitine 350 mg/kg/day divided into two daily doses for 4 days. The bone marrow was examined on day 1 and 5 after the last dose of roscovitine. On day 1, BFU-E decreased to less than 50% of the controls (P = 0.019). No decrease in BFU-E formation was observed on day 5. No significant effect was observed on CFU-GM and CFU-GEMM growth after the treatment with multiple doses of roscovitine. Single doses of roscovitine or dimethylsulfoxide did not affect the colony formation. We also studied the distribution of roscovitine to the bone marrow after a dose of 50 mg/kg was administered intraperitoneally. Only 1.5% of the drug was detected in the bone marrow. Thus, the roscovitine effect on hematopoietic progenitors in bone marrow in vivo is only transient. One reason may be that only a small fraction of roscovitine reaches the bone marrow. Another explanation may be the short half-life observed for roscovitine that might not allow enough cell exposure to the drug. However, the toxicity of roscovitine to hematopoietic progenitors in vitro is within the same exposure range as cytotoxicity to cancer cells. Thus, precaution should be taken in clinical trials, especially when combinations with myelosuppressive cytostatics are used