Antibacterial and brine shrimp lethality effect of marine actinobacterium Streptomyces sp. CAS72 against human pathogenic bacteria

Objective

To investigate the in vitro antibacterial activity against human pathogenic bacteria and brine shrimp lethality bioassay of the marine actinobacterium.

Methods

Forty six marine actinobacterial strains were isolated from sediment samples of Uppanar estuary, Cuddalore, India. Preliminary screening was done by cross-streak method and the potential strain was identified by morphological, chemotaxonomical and molecular methods. Fermentation was done and the metabolite was obtained by liquid-liquid extraction using ethyl acetate and purified by silica gel (100-200 mesh) column chromatography. The purified metabolite was tested for antibacterial activity, minimal inhibitory concentration and brine shrimp lethality bioassay.

Results

Among the forty six strains, CAS72 was found effective against human pathogenic bacteria. The strain CAS72 was identified as Streptomyces sp. The purified metabolite exhibited a significant in vitro antibacterial activity. The MIC value was also determined against human pathogenic bacteria and a strong cytotoxic activity in brine shrimp lethality assay was observed and the LC₅₀ value was 23.5 µg/mL.

Conclusions

The present investigation reveals that the marine actinobacteria are well obtainable in Uppanar estuary environment and it can provide a definite source for novel bioactive metabolites.     

Antibacterial activity of various honey types of Algeria against Pathogenic Gram–Negative Bacilli: Escherichia coli and Pseudomonas aeruginosa

ObjectiveTo assess the in vitro antibacterial activity of different honey types in Algeria on Gram negative organismes.MethodsDifferent concentrations (10, 30, 50, 70, 100 % v/v) of honey were studied in vitro using Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa). Briefly, two-fold dilutions of honey solutions were tested to determine the minimum inhibitory concentration (MIC) against each type of microorganism, followed by more assays within a narrower dilution range to obtain more precise MIC values. MIC was determined by both visual inspection and spectrophotometric assay at 620 nm. The antibacterial activity of these honey samples was determined by the disc and well diffusion method.ResultsThe zone diameter of inhibition of honey for P. aeruginosa and E. coli was 0–30 and 0–38 mm, respectively, while the MIC ranged 90–91% and 56–96%, respectively.ConclusionsThe results show that Algerian honeys possess antibacterial activity against Gram negative bacilli, and it can be developed into antibacterial agents.     

Antibacterial activity of honey alone and in combination with Nigella sativa seeds against Pseudomonas aeruginosa infection

ObjectiveTo evaluate the in vitro activities, of three honeys sample, and Nigella sativa (N. sativa) against Pseudomonas aeruginosa (P. aeruginosa) alone and in combination.MethodsThe antibacterial test and minimum inhibition concentration (MIC) was determined by using agar well diffusion and dilution methods respectively against P. aeruginosa.ResultsThe MIC for the three varieties of honey without N. sativa against P. aeruginosa ranged between 46% and 50% (v/v). Addition of N. sativa (8%) resulted in synergistic bactericidal activity. An MIC drop was noticed with each variety and it ranged between 77.77% and 84.21%.ConclusionsThese antibacterial properties would warrant further studies on the clinical applications of N. sativa and honey against P. aeruginosa.     

Protective Effect of Cornus mas Fruits Extract on Serum Biomarkers in CCl4-Induced Hepatotoxicity in Male Rats

Background:

Nowadays attention to use herbs such as cornelian cherry (Cornus mas) is increasing, which contains high levels of antioxidants and anthocyanins. Cornus mas fruits have been used for gastrointestinal and excretory disorders for many years in traditional medicine, also may improve liver and kidney functions, and have protective effects such as anti-allergic, antidiabetic, antibacterial, antimicrobial, antihistamine and antimalarial properties.

Objectives:

The aim of this study was to investigate protective effects of Cornus mas fruits extract on serum biomarkers in CCl₄-induced hepatotoxicity in male rats.

Materials and Methods:

Hepatotoxicity was induced by administration of carbon tetrachloride (1 mL/kg i.p.) in 1:1 dilution with olive oil. To evaluate the effect of Cornus mas fruits extract on disease progression, serum marker enzymes, serum total protein and albumin and liver lipid peroxidation were determined in CCl₄-induced hepatotoxicity.

Results:

Oral administration of Cornus mas fruits extract to rats for 14 days provided a significant (P < 0.05) hepatoprotection by decreasing elevated serum level of enzymes, total serum protein, albumin and liver lipid peroxidation content.

Conclusions:

Cornus mas fruit extract effect may be due to including some antioxidant components, which caused membrane stabilizing and normalization of fluctuated biochemical profiles induced by CCl₄ exposure. Our results validated the traditional use of Cornus mas in the treatment of liver disorders.     

Antioxidant and anti-inflammatory activity of Polygonatum sibiricum rhizome extracts

Objective

To investigate the antioxidant and anti-inflammatory activities of distilled water extract of fresh Polygonatum sibiricum (P. sibiricum) rhizome.

Methods

: The extracts were tested for antioxidant activity by using DPPH (1,1-diphenyl-2-picryl-hydrazyl), and hydroxyl (OH•) radicals scavenging activity. The level of intracellular reactive oxygen species (ROS) was determined in H₂O₂ treated chang liver cells. Anti-inflammatory activity was evaluated by the inhibition of nitric oxide (NO), inducible nitric oxide synthase (iNOS), as well as tumor necrosis factor-alpha (TNF-α) protein expression in a lipopolysaccharide stimulated Raw 264.7 murine macrophages cell line.

Results

: P. sibiricum water extracts scavenged DPPH, OH• radicals and decreased the level ROS. The extracts reduced NO reduction and inhibited the expression of iNOS and TNF-α proteins.

Conclusions

: The findings indicate that water extracts of P. sibiricum could be considered as natural antioxidants and anti-inflammatory agents for food and drug industries.     

Anti-Phospholipase A2 Receptor Antibodies Correlate with Clinical Status in Idiopathic Membranous Nephropathy

Summary

Background and objectives

Circulating autoantibodies against the M-type phospholipase A₂ receptor (anti-PLA₂R) were recently identified in the majority of patients in the United States with idiopathic membranous nephropathy (iMN). The objectives of this study were to assess the prevalence of anti-PLA₂R in a separate, European cohort of iMN patients and to correlate the presence of anti-PLA₂R with clinical parameters reflective of disease activity.

Design, setting, participants, & measurements

Anti-PLA₂R levels were blindly assessed by a Western blot immunoassay in 54 serum samples from 18 patients with iMN collected in various stages of clinical disease. Anti-PLA₂R levels were correlated with other clinical parameters.

Results

77.8% of iMN patients in our cohort had antibodies reactive with human PLA₂R. The antibody levels in these patients correlated strongly with both clinical status and proteinuria (r = 0.73, P < 0.01).

Conclusions

The role of PLA₂R as a major antigen in iMN was confirmed in an independent, European patient cohort, and levels of circulating anti-PLA₂R revealed a strong correlation with clinical disease activity. We propose that detection and measurement of these autoantibodies may provide a tool for monitoring of disease activity and treatment efficacy.     

Chemical composition and antibacterial activity of Pinus halepensis Miller growing in West Northern of Algeria

Objective

To find new bioactive natural products, the chemical composition and to sudy the antibacterial activity of essential oil components extracted from the aerial parts of the Algerian aromatic plant Pinus halepensis Miller (P. halepensis) (needles, twigs and buds).

Methods

The essential oil used in this study was isolated by hydrodistillation using a Clevenger-type apparatus according to the European Pharmacopoeia. The chemical composition was investigated using GC-retention indices (RI) and GC-MS.

Results

Forty-nine compounds, representing 97.9% of the total collective oil, were identified. Essential oil was dominated by hydrocarbon compounds (80.6%) especially monoterpenes (65.5%). The major compounds from ten oils stations were: myrcene (15.2%-32.0%), α-pinene (12.2%-24.5%), E-β-caryophyllene (7.0%-17.1%), terpinolene (1.8%-13.3%), 2-phenyl ethyl isovalerate (4.8%-10.9%), terpinene-4-ol (1.0%-8.2 %) and sabinene (1.5%-6.3%). The intra-species variations of the chemical compositions of P. halepensis aerial parts essential oils from ten Algerian sample locations were investigated using statistical analysis. Essential oil samples were clustered in 2 groups by hierarchical cluster analysis, according to their chemical composition. The essential oil revealed an interesting antimicrobial effect against Lysteria monocytogenes, Enterococcus faecalis, Pseudomonas aeruginosa, Acinetobacter baumanii, Citrobacter freundii and Klebsiella pneumoniae.

Conclusions

These results suggest that the essential oil from P. halepensis may be a new potential source as natural antimicrobial applied in pharmaceutical and food industries.     

Evaluation of hepatoprotective effect of methanolic extract of Clitoria ternatea (Linn.) flower against acetaminophen-induced liver damage

Objective

To evaluate the hepatoprotective and antioxidant activity of Clitoria ternatea (C. ternatea) flower extract against acetaminophen-induced liver toxicity.

Methods

The antioxidant property of C. ternatea flower extract was investigated by employing established in vitro antioxidant assay. The C. ternatea flower extract was studied in this work for its hepatoprotective effect against acetaminophen-induced liver toxicity in mice. Activity was measured by monitoring the levels of aspartate aminotransferase, alanine aminotransferase, billirubin and glutathione with histopathological analysis.

Results

The amount of total phenolics and flavonoids were estimated to be 105.40±2.47 mg/g gallic acid equivalent and 72.21±0.05 mg/g catechin equivalent respectively. The antioxidant activity of C. ternatea flower extract was 68.9% at a concentration of 1 mg/mL and was also concentration dependant, with an IC₅₀ value of 327.00 µg/mL. The results of acetaminophen-induced liver toxicity experiment showed that mice treated with the extract (200 mg/kg) showed a significant decrease in alanine aminotransferase, aspartate aminotransferase, and bilirubin levels, which were all elevated in the paracetamol group (P<0.05). Meanwhile, the level of glutathione was found to be restored in extract treated animals compared to the groups treated with acetaminophen alone (P<0.05). Therapy of extract also showed its protective effect on histopathological alterations and supported the biochemical finding.

Conclusion

The present work confirmed the hepatoprotective effect of C. ternatea flower against model hepatotoxicant acetaminophen.     

Antibacterial activity of various honey types of Algeria against Staphylococcus aureus and Streptococcus pyogenes

ObjectiveTo assess the in vitro antibacterial activity of honey from different geographical location on Gram negative organismes.MethodsDifferent concentrations (Undiluted honey, 10 %, 30%, 50% and 70% wt/vol) of honey were studied in vitro using Staphylococcus aureus (S. aureus) and Streptococcus pyogenes (S. pyogenes), briefly, two-fold dilutions of honey solutions were tested to determine the minimum inhibitory concentration (MIC) against each type of microorganism, followed by more assays within a narrower dilution range to obtain more precise MIC values. MICs were determined by both visual inspection and spectrophotometric assay at 620 nm. These honey samples were compared with standard antibiotics like ampicillin, penicillin G, amoxicillin, gentamycin, tobramycin, erythromycin and chloramphenicol was determined by the disc diffusion method.ResultsThe diameter of zone of the inhibition (ZDI) of honey has various concentrations tested for the isolates ranged 0–46 mm for S. aureus, 0–44 mm for S. pyogenes. While the MIC (%) ranged 12%-95%, 25%-73% respectively.ConclusionsAlgeria honey, in-vitro, possess antibacterial activity.     

A Subcutaneous Insulin Pharmacokinetic Model for Computer Simulation in a Diabetes Decision Support Role: Validation and Simulation

Objective

The goal of this study was to validate a previously derived and identified physiological subcutaneous (SC) insulin absorption model for computer simulation in a clinical diabetes decision support role using published pharmacokinetic summary measures.

Methods

Validation was performed using maximal plasma insulin concentration (C_max) and time to maximal concentration (t_max pharmacokinetic summary measures. Values were either reported or estimated from 37 pharmacokinetic studies over six modeled insulin types. A validation comparison was made to equivalent pharmacokinetic summary measures calculated from model generated curves fitted to respective plasma insulin concentration data. The validation result was a measure of goodness of fit. Validation for each reported study was classified into one of four cases.

Results

Of 37 model fits, 22 were validated on both the C_max and the t_max summary measures. Another 6 model fits were partially validated on one measure only due to lack of reporting on the second measure with errors to reported or estimated ranges of <12%. Another 7 studies could not be validated on either measure because of inadequate reported clinical data. Finally, 2 separate model fits to data from the same study failed the validation with 90 and 71% error on t_max only, which was likely caused by protocol-based error. No model fit failed the validation on both measures.

Conclusions

A previously derived and identified model was clinically validated for six insulin types using C_max and t_max summary measures from published pharmacokinetic studies. Hence, this article presents a clinically valid model that accounts for multiple nonlinear effects and six different types of SC insulin in a computationally modest form suitable for use in clinical decision support.     

Comparison of the OxyMask and Venturi mask in the delivery of supplemental oxygen: Pilot study in oxygen-dependent patients

BACKGROUND:

The OxyMask (Southmedic Inc, Canada) is a new face mask for oxygen delivery that uses a small ‘diffuser’ to concentrate and direct oxygen toward the mouth and nose. The authors hypothesized that this unique design would enable the OxyMask to deliver oxygen more efficiently than a Venturi mask (Hudson RCI, USA) in patients with chronic hypoxemia.

METHODS:

Oxygen-dependent patients with chronic, stable respiratory disease were recruited to compare the OxyMask and Venturi mask in a randomized, single-blind, cross-over design. Baseline blood oxygen saturation (SaO₂) was established breathing room air, followed in a random order by supplemental oxygen through the OxyMask or Venturi mask. Oxygen delivery was titrated to maintain SaO₂ 4% to 5% and 8% to 9% above baseline for two separate 30 min periods of stable breathing. Oxygen flow rate, partial pressure of inspired and expired oxygen (PO₂) and carbon dioxide (PCO₂), minute ventilation, heart rate, nasal and oral breathing, SaO₂ and transcutaneous PCO₂ were collected continuously. The study was repeated following alterations to the OxyMask design, which improved clearance of carbon dioxide.

RESULTS:

Thirteen patients, aged 28 to 79 years, were studied initially using the original OxyMask. Oxygen flow rate was lower, inspired PO₂ was higher and expired PO₂ was lower while using the OxyMask. Minute ventilation and inspired and expired PCO₂ were significantly higher while using the OxyMask, whereas transcutaneous PCO₂, heart rate and the ratio of nasal to oral breathing did not change significantly throughout the study. Following modification of the OxyMask, 13 additional patients, aged 18 to 79 years, were studied using the same protocol. The modified OxyMask provided a higher inspired PO₂ at a lower flow rate, without evidence of carbon dioxide retention.

CONCLUSIONS:

Oxygen is delivered safely and more efficiently by the OxyMask than by the Venturi mask in stable oxygen-dependent patients.     

Evaluation of group A1B erythrocytes converted to type as group O: studies of markers of function and compatibility

Background

Enzymatic conversion of blood group A₁B red blood cells (RBC) to group O RBC (ECO) was achieved by combined treatment with α-galactosidase and α-N-acetylgalactosaminidase. The aim of this study was to evaluate the function and safety of these A₁B-ECO RBC in vitro.

Materials and methods

A 20% packed volume of A₁B RBC was treated with enzymes in 250 mM glycine buffer, pH 6.8. The efficiency of the conversion of A and B antigen was evaluated by traditional typing in test tubes, gel column agglutination technology and fluorescence-activated cell sorting (FACS) analysis. The physiological and metabolic parameters of native and ECO RBC were compared, including osmotic fragility, erythrocyte deformation index, levels of 2,3-diphosphoglycerate, ATP, methaemoglobin, free Na⁺, and free K⁺. The morphology of native and ECO RBC was observed by scanning electron microscopy. Residual α-galactosidase or α-N-acetylgalactosaminidase in A₁B-ECO RBC was detected by double-antibody sandwich ELISA method. Manual cross-matching was applied to ensure blood compatibility.

Results

The RBC agglutination tests and FACS results showed that A₁B RBC were efficiently converted to O RBC. Functional analysis suggested that the conversion process had little impact on the physiological and metabolic parameters of the RBC. The residual amounts of either α-galactosidase or α-N-acetylgalactosaminidase in the A₁B-ECO RBC were less than 10 ng/mL of packed RBC. About 18% of group B and 55% of group O sera reacted with the A₁B-ECO RBC in a sensitive gel column cross-matching test.

Discussion

The conversion process does not appear to affect the morphological, physiological or metabolic parameters of A₁B-ECO RBC. However, the A₁B-ECO RBC still reacted with some antigens. More research on group O and B sera, which may partly reflect the complexity of group A₁ the safety of A₁B-ECO RBC is necessary before the application of these RBC in clinical transfusion.     

MicroRNA characterize genetic diversity and drug resistance in pediatric acute lymphoblastic leukemia

Background

MicroRNA regulate the activity of protein-coding genes including those involved in hematopoietic cancers. The aim of the current study was to explore which microRNA are unique for seven different subtypes of pediatric acute lymphoblastic leukemia.

Design and Methods

Expression levels of 397 microRNA (including novel microRNA) were measured by quantitative real-time polymerase chain reaction in 81 cases of pediatric leukemia and 17 normal hematopoietic control cases.

Results

All major subtypes of acute lymphoblastic leukemia, i.e. T-cell, MLL-rearranged, TEL-AML1-positive, E2A-PBX1-positive and hyperdiploid acute lymphoblastic leukemia, with the exception of BCR-ABL-positive and ‘B-other’ acute lymphoblastic leukemias (defined as precursor B-cell acute lymphoblastic leukemia not carrying the foregoing cytogenetic aberrations), were found to have unique microRNA-signatures that differed from each other and from those of healthy hematopoietic cells. Strikingly, the microRNA signature of TEL-AML1-positive and hyperdiploid cases partly overlapped, which may suggest a common underlying biology. Moreover, aberrant down-regulation of let-7b (~70-fold) in MLL-rearranged acute lymphoblastic leukemia was linked to up-regulation of oncoprotein c-Myc (P_FDR<0.0001). Resistance to vincristine and daunorubicin was characterized by an approximately 20-fold up-regulation of miR-125b, miR-99a and miR-100 (P_FDR≤0.002). No discriminative microRNA were found for prednisolone response and only one microRNA was linked to resistance to L-asparaginase. A combined expression profile based on 14 microRNA that were individually associated with prognosis, was highly predictive of clinical outcome in pediatric acute lymphoblastic leukemia (5-year disease-free survival of 89.4%±7% versus 60.8±12%, P=0.001).

Conclusions

Genetic subtypes and drug-resistant leukemic cells display characteristic microRNA signatures in pediatric acute lymphoblastic leukemia. Functional studies of discriminative and prognostically important microRNA may provide new insights into the biology of pediatric acute lymphoblastic leukemia.     

Model-Based Insulin Sensitivity as a Sepsis Diagnostic in Critical Care

Background

Timely diagnosis and treatment of sepsis in critical care require significant clinical effort, experience, and resources. Insulin sensitivity is known to decrease with worsening condition and could thus be used to aid diagnosis. Some glycemic control protocols are able to identify insulin sensitivity in real time.

Methods

Receiver operating characteristic curves and cutoff insulin sensitivity values for diagnosing sepsis were calculated for model-based insulin sensitivity (S_I) and a simpler metric (SS_I) that was estimated from glycemic control data of 30 patients with sepsis and can be calculated in real time without use of a computer. Results were compared to the insulin sensitivity profiles of a general intensive care unit population of 113 patients without sepsis and 30 patients with sepsis, comprising a total of 26,453 patient hours. Patients with sepsis were identified as having sepsis based on a sepsis score (ss) of 3 or higher (ss = 0 – 4 for increasing severity). Patients with type I or type II diabetes were excluded. Ethics approval for this study was granted by the South Island Regional Ethics Committee.

Results

Receiver operating characteristic cutoff values of S_I = 8 × 10-5 liter mU⁻¹ min⁻¹ and SS_I = 2.8 × 10-4 liter mU⁻¹ min⁻¹ were determined for ss ≥ 3. The model-based S_I fell below this value in 15% of all patient hours. The S_I test had a negative predictive value of 99.8%. The test sensitivity was 78% and specificity was 82%. However, the positive predictor value was 2.8%. Slightly lower sensitivity (68.8%) and specificity (81.7%), but equally good negative prediction (99.7%), were obtained for the estimated SS_I.

Conclusions

Insulin sensitivity provides a negative predictive diagnostic for sepsis. High insulin sensitivity rules out sepsis for the majority of patient hours and may be determined noninvasively in real time from glycemic control protocol data. Low insulin sensitivity is not an effective diagnostic, as it can equally mark the presence of sepsis or other conditions.     

The role of matched sibling donor allogeneic stem cell transplantation in pediatric high-risk acute myeloid leukemia: results from the AML-BFM 98 study

Background

The role of allogeneic stem cell transplantation in post-remission management of children with high-risk acute myeloid leukemia remains controversial. In the multi-center AML-BFM 98 study we prospectively evaluated the impact of allogeneic stem cell transplantation in children with high-risk acute myeloid leukemia in first complete remission.

Design and Methods

HLA-typed patients with high-risk acute myeloid leukemia, who achieved first complete remission (n=247), were included in this analysis. All patients received double induction and consolidation. Based on the availability of a matched-sibling donor, patients were allocated by genetic chance to allogeneic stem cell transplantation (n=61) or chemotherapy-only (i.e. intensification and maintenance therapy; n=186). The main analysis was done on an intention-to-treat basis according to this allocation.

Results

Intention-to-treat analysis did not show a significantly different 5-year disease-free survival (49±6% versus 45±4%, P_{log rank}=0.44) or overall survival (68±6% versus 57±4%, P_{log rank}=0.17) between the matched-sibling donor and no-matched-sibling donor groups, whereas late adverse effects occurred more frequently after allogeneic stem cell transplantation (72.5% versus 31.8%, P_Fischer<0.01). These results were confirmed by as-treated analysis corrected for the time until transplantation (5-year overall survival: 72±8% versus 60±4%, P_Mantel-Byar 0.21). Subgroup analysis demonstrated improved survival rates for patients with 11q23 aberrations allocated to allogeneic stem cell transplantation (5-year overall survival: 94±6% versus 52±7%, P_log-rank=0.01; n=18 versus 49) in contrast to patients without 11q23 aberrations (5-year overall survival: 58±8% versus 55±5%, P_log-rank=0.66).

Conclusions

Our analyses defined a genetic subgroup of children with high-risk acute myeloid leukemia who benefited from allogeneic stem cell transplantation in the prospective multi-center AML-BFM 98 study. For the remainder of the pediatric high-risk acute myeloid leukemia patients the prognosis was not improved by allogeneic stem cell transplantation, which was, however, associated with a higher rate of late sequelae.     

CHADS2 versus CHA2DS2-VASc score in assessing the stroke and throm-boembolism risk stratification in patients with atrial fibrillation: a systematic review and meta-analysis

Objective To perform a systematic review and meta-analysis of the predictive abilities of CHADS2 and CHA2DS2-VASc in stroke and thromboembolism risk stratification of atrial fibrillation (AF) patients....     

Immunoglobulin subclass 4 for the diagnosis of immunoglobulin subclass 4-associated diseases in an unselected liver and pancreas clinic population

Aims

The diagnosis of autoimmune pancreatitis (AIP) and immunoglobulin subclass 4 (IgG₄)-associated cholangitis (IAC) is based on imaging studies, serology, histology and a response to steroid therapy. The major serological finding is an elevation of the serum IgG₄ concentration. Previous studies have shown that its sensitivity is about 70% and its specificity exceeds 90% at a cut-off of 140 mg/dl in selected patient populations. The aim of the present study was to assess the performance of serum IgG₄ as a diagnostic parameter in an unselected liver and pancreas clinic population.

Methods and results

IgG₄ was prospectively determined in 1412 patients and clinical diagnoses were recorded from a review of patient charts. The prevalence of AIP or IAC in the entire cohort was 1.1% (n = 15). The sensitivity of IgG₄ for the diagnosis of AIP and IAC was 80% and the specificity was 86% at a cut-off value of ≥135 mg/dl. The positive predictive value and the negative predictive value were 6% and 99.7%, respectively. The most common differential diagnosis in patients with elevated IgG₄ was liver cirrhosis.

Conclusion

IgG₄ has a reasonable sensitivity and specificity in a liver and pancreas clinic population, where liver cirrhosis appears to be the most frequent differential diagnosis for elevated IgG₄ concentrations.     

A spectrum of dynamic insulin sensitivity test protocols

Background

Numerous tests have been developed to estimate insulin sensitivity (SI). However, most of the established tests are either too expensive for widespread application or do not yield reliable results. The dynamic insulin sensitivity and secretion test (DISST) uses assays of glucose, insulin, and C-peptide from nine samples to quantify SI and endogenous insulin secretion (U_N) at a comparatively low cost. The quick dynamic insulin sensitivity test has shown that the DISST SI values are robust to significant assay omissions.

Methods

Eight DISST-based variations of the nine-sample assay regimen are proposed to investigate the effects of assay omission within the DISST-based framework. SI and U_N were identified using the fully-sampled DISST and data from 218 nine-sample tests undertaken in 74 female individuals with elevated diabetes risk. This same data was then used with appropriate assay omissions to identify SI and U_N with the eight DISST-based assay variations.

Results

Median intraprocedure proportional difference between SI values from fully-sampled DISST and the DISST-based variants was in the range of -17.9 to 7.8%. Correlations were in the range of r = 0.71 to 0.92 with the highest correlations between variants with the greatest commonality with the nine-sample DISST. Metrics of U_N correlated relatively well between tests when C-peptide was assayed (r = 0.72 to 1) but were sometimes not well estimated when samples were not assayed for C-peptide (r = -0.14 to 0.75).

Conclusions

The DISST-based spectrum offers a series of tests with very distinct compromises of information yield, accuracy, assay cost, and clinical intensity. Thus, the spectrum of tests has the potential to enable researchers to better allocate funds by selecting an optimal test configuration for their particular application.     

Proteasome inhibition enhances antitumour effects of gemcitabine in experimental pancreatic cancer

Background:

The clinical benefit of gemcitabine, the standard systemic therapy of pancreatic cancer (PaCa), remains modest as a result of high chemoresistance. The proteasome inhibitor bortezomib has antitumour activity against PaCa in vitro and in vivo. We examined the antitumour activity of combination PaCa therapy with bortezomib and gemcitabine.

Methods:

Cell proliferation assays were performed using WST-1 reagent. Protein expression was determined by Western blotting. Efficacy of bortezomib and/or gemcitabine was tested in vivo in a survival study.

Results:

Bortezomib at 10 µM caused 29% and 72% inhibition in AsPC-1 PaCa cell proliferation at 48 and 96 h incubation, respectively. Bortezomib was even more active against PaCa cell lines Panc-1 and MiaPaCa, with 80% inhibition of proliferation at 48 h. The combination of bortezomib and gemcitabine inhibited AsPC-1 proliferation more effectively compared with each single agent alone. Poly(ADP-ribose) polymerase (PARP) cleavage, an apoptotic indicator, reached 6.6-, 2- and 8.5-fold over controls for bortezomib, gemcitabine and the combination. The median survival was 31 (controls and bortezomib), 40 (gemcitabine) and 48 days (combination), respectively (P < 0.002).

Conclusions:

Bortezomib and gemcitabine demonstrate additive antitumour activity in vitro and in an experimental PaCa model, indicating the potential for clinical PaCa benefits of additional multiagent therapies that will be based upon the bortezomib and gemcitabine combination.