Minimum Effective Concentration Research Articles

Multicenter Study of Susceptibility of Aspergillus Species Isolated from Iranian University Hospitals to Seven Antifungal Agents.

ABSTRACTAspergillus species are a major cause of life-threatening invasive infections and noninvasive diseases. This study seeks to investigate the frequency of Aspergillus species among Iranian patients and their susceptibility to seven antifungals. In a cross-sectional study, 233 Aspergillus isolates were collected from 11 university hospitals in Iran between 2018 and 2021. Aspergillus isolates were identified based on colony morphology, microscopic characteristics, PCR-restriction fragment length polymorphism (RFLP), and sequencing of the beta-tubulin gene. The CLSI M38-A2 reference methodology was used for antifungal susceptibility testing of amphotericin B, voriconazole, posaconazole, itraconazole, luliconazole, isavuconazole, and caspofungin. Members of Aspergillus section Flavi (117/233, 50.2%), Aspergillus section Nigri (77/233, 33.1%), Aspergillus section Fumigati (21/233, 9%), Aspergillus section Terrei (14/233, 6%), Aspergillus pseudodeflectus (2/233, 0.85%), and Aspergillus melleus (2/233, 0.85%) were isolated from the samples. The lowest 0.25 MIC90 values for all isolates tested were for luliconazole (0.016 μg/mL) and isavuconazole (0.250 μg/mL), and the highest value was observed for itraconazole (≥ 8μg/mL). The 90% minimum effective concentration (MEC90) value for caspofungin was 0.125 μg/mL. MIC90 values for voriconazole, amphotericin B, and posaconazole were 1, 2, and 2 μg/mL, respectively. The non-wild-type species were presented for amphotericin B (3%), voriconazole (1.3%), posaconazole (2.6%), luliconazole (1.3%), isavuconazole (1.7%), and caspofungin (4.7%). Positive correlations in the MIC values of azole antifungals were observed, and using one azole increases the MIC value rates of other ones. None of the species were pan-azole resistant. Species of Aspergillus section Flavi were the most common Aspergillus species isolated from Iranian samples. Luliconazole, caspofungin, and isavuconazole present the most effective antifungal agents for treatment of infection due to Aspergillus species. Susceptibility tests should be performed frequently in each region for the best management of patients.IMPORTANCE Aspergillus species are the leading cause of invasive aspergillosis in immunocompromised hosts. The susceptibility of Aspergillus species to antifungal agents might be different. Azole-resistant species have emerged worldwide. Performing susceptibility testing in each region can help in the best management of patients. Here, we show the epidemiology and distribution of Aspergillus species in Iran and their susceptibility patterns for seven antifungal agents. The significant points of the present study are that species of Aspergillus section Flavi are the most prevalent Aspergillus species isolated from 11 university hospitals. Luliconazole, caspofungin, and isavuconazole were effective antifungal agents against all Aspergillus species.

Effect of phytochemical-filled microcapsules with antifungal activity on material properties and dimensional accuracy of denture base resin for three-dimensional printing

BackgroundStudies on the material properties and dimensional accuracy of three-dimensionally (3D) printed denture base containing microcapsules with antifungal phytochemicals are lacking.MethodsTwo types of phytochemicals (phytoncide A and B) with antifungal activity were microencapsulated. The 3D-printed denture base specimens with minimum and maximum effective concentrations of microcapsules (6 and 8 wt% for phytoncide A; 15 and 25 wt% for phytoncide B) were prepared. The morphological changes of C. albicans on 3D-printed denture base with microcapsules was microscopically observed. The degree of conversion of 3D-printed denture base with microcapsules investigated. The microhardness and flexural strength values were also measured to evaluate the mechanical properties of 3D-printed denture bases. The dimensional accuracy (trueness) of the specimens with microcapsules was measured as root-mean-square values (RMS) for the whole, upper, and side surfaces of the specimens as well as their total height. For the degree of conversion, microhardness, and flexural strength values, the Kruskal–Wallis analysis and a post-hoc comparison using Mann–Whitney U test was performed. For the analysis of trueness (RMS), the one-way analysis of variance and a post-hoc comparison using Tukey’s method was conducted (α = 0.05).ResultsAt both maximum and minimum effective concentrations of microcapsules, cell surface disruption or membrane breakdown of fungal cells were observed in the specimens. The groups with microcapsules (both phytoncide A- and B-filled) showed significantly lower microhardness and elastic modulus values than the control group (all, P = 0.001). For the trueness, all the RMS values of the whole, upper, and side surfaces of the specimens with microcapsules were less than 100 µm, although significantly higher than those without (all, P = 0.001). The mean flexural strength values of the groups with phytoncide A-filled microcapsule were higher than 65 MPa, not statistically different from that of the control group (all, P > 0.05). However, the groups with phytoncide B-filled microcapsules showed significantly lower values than the control (all, P = 0.001).ConclusionsWithin the limitations of this in-vitro study, the 3D-printed denture base containing 6 wt% of phytoncide A-filled microcapsules was clinically acceptable in terms of antifungal activity, dimensional accuracy, and flexural strength.

Absorption of grapiprant in red-tailed hawks (Buteo jamaicensis) is decreased when administered with food.

Describe the pharmacokinetics of grapiprant administered orally with food to red-tailed hawks (RTHAs; Buteo jamaicensis) and compare the results with previously described grapiprant pharmacokinetics administered without food in this species. 6 healthy adult RTHA (3 males, 3 females) under human care. A single dose of grapiprant (30 mg/kg) was given orally to RTHAs, followed by force-feeding. Blood samples were obtained at 14 time points for 120 hours postgrapiprant administration. Plasma concentrations of grapiprant were measured via tandem liquid chromatography-mass spectrometry. Nonparametric superimposition using pharmacokinetic modeling software used plasma concentrations to calculate simulations of grapiprant plasma concentrations for 30 mg/kg administered orally with food every 12 hours. The arithmetic mean maximum plasma concentration was 405.8 ng/mL, time to maximum plasma concentration was 16 hours, and harmonic mean terminal half-life was 15.6 hours. Simulations determined 30 mg/kg every 12 hours could attain minimum effective concentrations (> 164 ng/mL) reported in dogs for a sustained period of approximately 20 hours. Grapiprant plasma concentrations were achieved above the canine therapeutic concentrations within 16 hours postmedication. Mean concentrations were maintained for approximately 20 hours. Simulations support a dosing frequency of 12-hour intervals with food reaching minimum effective concentrations established for canines, although it is unknown whether these plasma concentrations are therapeutic for birds. Bioaccumulation was not noted on simulations secondary to increased grapiprant administration. Further research including multidose assessments at this current dose with food, in vitro pharmacological characterization, and pharmacodynamic studies in this species are warranted.

Caspofungin Cerebral Penetration and Therapeutic Efficacy in Experimental Cerebral Aspergillosis.

ABSTRACTDespite best available therapy, cerebral aspergillosis is an often-lethal complication of disseminated aspergillosis. There is an urgent need to expand the currently limited therapeutic options. In this study, we assessed cerebral drug exposure and efficacy of caspofungin (CAS) using a lethal infant rat model of cerebral aspergillosis. Eleven-day-old Wistar rats were infected by intracisternal injection of Aspergillus fumigatus conidia. Treatment started after 22 h and was continued for 10 days. Regimens were CAS 1 mg/kg/day intraperitoneally (i.p.), liposomal amphotericin B (L-AmB) 5 mg/kg/day i.p., and both drugs combined at the same dose i.p. Infected controls were given NaCl 0.85% i.p. Primary endpoints assessed were survival, cerebral fungal burden, galactomannan index, and drug concentrations in brain homogenate at 2, 3, 5, and 11 days after infection. Compared to those of controls (4.4 ± 2.7 days), survival times were increased by treatment with CAS alone (10.3 ± 1.7 days; P < 0.0001) and CAS combined with L-AmB (9.3 ± 2.8 days; P < 0.0001). In contrast, survival time of L-AmB-treated animals (4.3 ± 3.1 days) was not different from that of controls. Cerebral fungal burden and galactomannan index declined in all animals over time, without significant differences between controls and treated animals. CAS trough levels in brain tissue were between 0.84 and 1.4 μg/g, concentrations we show to be associated with efficacy. AmB trough levels in brain tissue were higher than the MIC of the A. fumigatus isolate. In summary, CAS concentrations in brain tissue suggest it may be therapeutically relevant and it significantly improved survival in this lethal model of cerebral aspergillosis in nonneutropenic rats. The clinical efficacy of CAS treatment for cerebral aspergillosis merits further study.IMPORTANCE Treatment options for cerebral aspergillosis, an often-lethal disease, are limited. The echinocandins (caspofungin is one of them) are not recommended treatment because their brain tissue penetration is often considered insufficient. In a nursing rat model of cerebral aspergillosis that mimics human disease, we found potentially therapeutically relevant concentrations of caspofungin in brain tissue and prolonged survival of caspofungin-treated animals. The efficacy of caspofungin in the treatment of cerebral aspergillosis documented here, if confirmed in other animal models (especially immunosuppressed murine models) and by using additional Aspergillus isolates across a range of CAS minimal effective concentrations (MECs), would suggest that caspofungin merits further study as a treatment option for patients suffering from aspergillosis disseminated to the brain.

The Caspofungin Paradoxical Effect is a Tolerant "Eagle Effect" in the Filamentous Fungal Pathogen Aspergillus fumigatus.

ABSTRACTCell responses against antifungals other than resistance have rarely been studied in filamentous fungi, while terms such as tolerance and persistence are well-described for bacteria and increasingly examined in yeast-like organisms. Aspergillus fumigatus is a filamentous fungal pathogen that causes a disease named aspergillosis, for which caspofungin (CAS), a fungistatic drug, is used as a second-line therapy. Some A. fumigatus clinical isolates can survive and grow in CAS concentrations above the minimum effective concentration (MEC), a phenomenon known as “caspofungin paradoxical effect” (CPE). Here, we evaluated the CPE in 67 A. fumigatus clinical isolates by calculating recovery rate (RR) values, where isolates with an RR of ≥0.1 were considered CPE+ while isolates with an RR of <0.1 were classified as CPE–. Conidia produced by three CPE+ clinical isolates, CEA17 (RR = 0.42), Af293 (0.59), and CM7555 (0.38), all showed the ability to grow in high levels of CAS, while all conidia produced by the CPE– isolate IFM61407 (RR = 0.00) showed no evidence of paradoxical growth. Given the importance of the calcium/calcineurin/transcription factor-CrzA pathway in CPE regulation, we also demonstrated that all ΔcrzACEA17 (CPE+) conidia exhibited CPE while 100% of ΔcrzAAf293 (CPE–) did not exhibit CPE. Because all spores derived from an individual strain were phenotypically indistinct with respect to CPE, it is likely that CPE is a genetically encoded adaptive trait that should be considered an antifungal-tolerant phenotype. Because the RR parameter showed that the strength of the CPE was not uniform between strains, we propose that the mechanisms which govern this phenomenon are multifactorial.

Quenching the Macroporous Collapse of Polyelectrolyte Multilayer Films for Repeated Drug Loading

Macroporous structures can be developed within polyelectrolyte multilayer films for efficient drug loading, but these structures tend to collapse or fracture during conventional drying procedures. Herein, a facile dehydrating method for macroporous polyelectrolyte multilayer films is proposed using solvent exchange to ethanol and then spontaneous evaporation. During these processes, the collapse of the macroporous structures can be effectively avoided, which can be ascribed to a combined effect of two factors. On one hand, capillary pressure during ethanol evaporation is relatively small since the surface tension of ethanol is much lower than that of water. On the other hand, solvent exchange suppresses the interdiffusion of polyelectrolytes and substantially increases the mechanical strength of the macroporous films, more than three orders of magnitude, making the pore walls highly tolerant of the capillary pressure. The stability of macroporous polyelectrolyte films to ethanol enables the repeated wicking from the ethanol solution of drugs, leading to a higher loading beyond previous studies. Such a high loading is favorable for the long-term release of drugs from the surfaces of modified substrates and maintaining a local drug concentration above the minimum effective concentration.

Surface functionalization of poly(dimethylsiloxane) substrates facilitates culture of pre-implantation mouse embryos by blocking non-selective adsorption.

Poly(dimethylsiloxane) (PDMS) is widely used in biomedical settings such as microfluidics for its optical transparency, castability, gas permeability and relative biocompatibility. While PDMS devices with certain modifications or treatments have been used for mammalian pre-implantation embryo culture, it is unclear why native PDMS leads to significant embryo death. In this study, we employ Nile Red as a model hydrophobic small molecule to demonstrate that significant hydrophobic sequestration occurs on native PDMS substrates even with a bovine serum albumin-containing KSOM pre-equilibration. Our results suggest that this small molecule sequestration has detrimental effects on mouse embryo development in PDMS static culture wells, with 0% blastocyst development rates from embryos cultured on native PDMS. We found that prior saturation of the PDMS culture well with water vapour only rescues about 10% of blastocyst development rates, indicating osmolality alone is not responsible for the high rates of embryo arrest. We also present a safe and simple Pluronic F127 pretreatment for PDMS substrates that successfully circumvented the harmful effects of native PDMS, achieving a blastocyst and implantation rate akin to that of our polystyrene controls. Our results call into question how researchers and clinicians can account for the alterations in medium composition and embryo secretions when using hydrophobic substrates, especially in the mammalian embryo culture setting where minimum effective concentrations of peptides and amino acids are commonplace.

Relationship between achievement of major molecular response or deep molecular response and nilotinib plasma concentration in patients with chronic myeloid leukemia receiving first-line nilotinib therapy.

We evaluated the plasma exposure and response relationships of nilotinib for patients with newly diagnosed chronic myeloid leukemia (CML) in real-world practice. For the 26 patients enrolled in this study, at 3, 6, 12, and 24months after nilotinib administration, the trough plasma concentrations (Ctrough) of nilotinib were analyzed. The relationships between nilotinib Ctrough and the molecular response to nilotinib treatment at each point (each n = 26) were evaluated. Median nilotinib Ctrough values were significantly higher in patients with a major molecular response (MMR) at 3months than in patients without an MMR (809 and 420ng/mL, respectively; P = 0.046). Based on the area under the receiver-operating characteristic curve, the threshold value of the nilotinib Ctrough at 3months for predicting MMR achievement was 619ng/mL at the best sensitivity (71.4%) and specificity (77.8%). Patients with a nilotinib Ctrough of above 619ng/mL had a significantly shorter time to achievement of a deep molecular response (DMR; 9.0 and 18.0months, respectively; P = 0.020) and higher rates of DMR by 2years in Kaplan-Meier plots (P = 0.025) compared with that in patients with a nilotinib Ctrough of less than 619ng/mL. For patients with newly diagnosed CML, the nilotinib dose may be adjusted using a Ctrough of above 619ng/mL as the minimum effective concentration, i.e., the lowest concentration required for MMR or DMR achievement within a shorter time, during early stages after beginning therapy to obtain faster and deeper clinical responses.

The 90% minimum effective volume and concentration of ropivacaine for ultrasound-guided median nerve block in children aged 1–3 years: A biased-coin design up-and-down sequential allocation trial

BackgroundMedian nerve block can provide excellent analgesia during open surgery for trigger thumb in children. However, no data on the 90% minimum effective volume (MEV90) and concentration (MEC90) of ropivacaine for ultrasound-guided median nerve block in pediatric patients have been reported. DesignA prospective two-phase study with an up-and-down sequential allocation trial using a biased coin design. PatientsChildren aged 1–3 years are experiencing open surgery for trigger thumb. InterventionThis study has 2 parts, one for MEV90 and subsequently studied MEC90 from the former part of the study. The MEV90 and MEC90 of ropivacaine for each subsequent patient were determined by the response of the previous patient, with the biased coin design up-and-down sequential allocation trial. The interval of -volume or concentration was -0.1 ml or 0.01%, respectively. MeasurementsThe MEV90 and MEC90 of ropivacaine for ultrasound-guided median nerve block in pediatric patients, were then used to estimate the 99% minimum effective volume (MEV99) and concentration (MEC99). The patient's general condition, postoperative pain, and adverse events. Main resultsA total of one hundred and eighteen children were enrolled for the study, and 56 and 62 patients were enrolled for the MEV90 and MEC90 studies, respectively. The MEV90 of 0.2% ropivacaine was 1.44 ml (95% CI 1.043 ml, 1.466 ml), and the MEC90 of 1.5 ml ropivacaine was 0.195% (95% CI 0.159%, 0.197%). There were no adverse events that occurred. ConclusionFor ultrasound-guided median nerve block in children aged 1–3 years old with trigger finger undergoing open surgery, the MEV90 of 0.2% ropivacaine is 1.44 ml (95% CI 1.043 ml, 1.466 ml), and the MEC90 of 1.5 ml of ropivacaine is 0.195% (95% CI 0.159%, 0.197%).

Commercial Methods for Antifungal Susceptibility Testing of Yeasts: Strengths and Limitations as Predictors of Resistance.

Susceptibility testing can yield variable results because it is method (commercial or reference), agent, and species dependent. Therefore, in order for results to be clinically relevant, MICs (minimal inhibitory concentrations) or MECs (minimal effective concentrations) should help in selecting the best treatment agent in the clinical setting. This is accomplished by categorical endpoints, ideally, breakpoints (BPs) and/or ECVs/ECOFFs (epidemiological cutoff values). BPs and ECVs are available by the reference methods (CLSI [Clinical and Laboratory Standards Institute] and EUCAST [European Committee on Antifungal Susceptibility Testing]) for a variety of species/agent combinations. The lack of clinical data precludes establishment of BPs for susceptibility testing by the commercial methods and ECVs have only been calculated for the Etest and SYO assays. The goal of this review is to summarize the variety of commercial methods for antifungal susceptibility testing and the potential value of Etest and SYO ECVs for detecting mutants/non-wild type (NWT) Candida isolates. Therefore, the literature search focused on publications where the commercial method, meaning MICs and ECVs, were reported for specific NWT isolates; genetic mutations have also been listed. For the Etest, the best performers recognizing the NWT were anidulafungin ECVs: 92% for the common species; 97% for C. glabrata and fluconazole ECVs, mostly for C. parapsilosis (45 NWT isolates). By the SYO, posaconazole ECVs recognized 93% of the C. albicans and 96% of the C. parapsilosis NWT isolates and micafungin ECVs 94% (mostly C. albicans and C. glabrata). Smaller sets, some with clinical data, were also listed. These are promising results for the use of both commercial methods to identify antifungal resistance (NWT isolates). However, ECVs for other species and methods need to be defined, including the C. neoformans complex and emerging species.

Model for Long Acting Injectables (Depot Formulation) Based on Pharmacokinetics and Physical Chemical Properties.

The objective was to develop a model to a priori identify the most suitable depot technology for a candidate based upon its therapeutic index (TI), pharmacokinetics (PK), and physical chemical properties. A depot map of release rates needed to achieve target PK in TI against release rates predicted based on intrinsic dissolution rate (IDR) and particle size (PS) clearly identified three zones: (a) products and candidates around the line of identity for which suspension is the appropriate depot technology, (b) area to the right of line of identity in which depot candidates would require a controlled release technology such as PLGA microspheres since in vivo release rate needed for PK in TI is significantly lower than predicted based on IDR and PS, and (c) area to the left of the line of identity where IDR is not sufficient to achieve target in vivo release rate for PK in TI and hence enhanced dissolution is needed such as with nanoparticles. Dose-solubility technology map of approved depot products and candidates showed clusters of products around a depot technology such as suspensions and microspheres, for drugs with high dose/low solubility and low dose/high solubility compounds, respectively. Novel PK-based computational tool showed how all combinations of depot doses and release rate constants for a candidate can be calculated to achieve plasma levels within the TI bounded by minimum effective and minimum toxic concentrations (MEC and MTC). The PK predictions for several drugs such as estradiol, risperidone, medroxyprogesterone acetate (MPA), and ziprasidone showed how these predictions can guide scientists to target specific depot doses and release rates into the depot formulation. In parallel, IDR of depot compounds clearly showed differentiation of compounds by successful depot technologies to achieve target dose and duration. For drugs with IDR between 0.1 and 1 mg/h/cm2, aqueous suspension has successfully delivered depot PK profile, while for candidates with IDRs greater than 1 mg/h/cm2, controlled release technology such as microsphere or in situ gel was required. The framework, prediction tools, and depot map will reduce the need for semi-empirical formulation work and preclinical studies to design depot formulations. Graphical Abstract.

Alternative trastuzumab dosing strategies in HER2-positive early breast cancer are associated with patient out-of-pocket savings

Patients with breast cancer frequently experience financial hardship, often due to the high costs of anti-cancer drugs. We sought to develop alternative trastuzumab dosing strategies, compare their pharmacokinetic effectiveness to standard dosing, and assess the expected financial implications of transitioning to them. We extracted clinical data from the records of 135 retrospectively identified patients with HER2-positive early breast cancer at a single, urban comprehensive cancer center who were treated with trastuzumab between 2017 and 2019. We performed pharmacokinetic simulations on a range of trastuzumab dose levels and frequencies, assessing efficacy by trough trastuzumab concentration (Ctrough) and population and individual likelihoods of Ctrough exceeding trastuzumab minimum effective concentration (MEC). We performed deterministic financial modeling to estimate the treatment-associated financial savings from alternative dosing strategies. Trastuzumab maintenance doses of 4 mg/kg every 3 weeks (Q3W) and 6 mg/kg every 4 weeks (Q4W) had nearly identical probabilities of Ctrough being above MEC as standard of care 6 mg/kg every 3 weeks. In the primary financial analysis, both trastuzumab 4 mg/kg Q3W and 6 mg/kg Q4W were associated with significant drug- and administration-related out-of-pocket cost savings over the duration of therapy, ranging from $765 (neoadjuvant, Q4W) to $2791 (adjuvant, Q4W). In particular, Q4W trastuzumab increased savings related to lost wages and travel cost avoidance. Low-dose and reduced frequency trastuzumab in appropriately selected patients may significantly reduce total drug utilization and meaningfully reduce patient financial toxicity. Prospective clinical trials evaluating low-dose or reduced-frequency administration of therapeutic monoclonal antibodies are warranted and needed.

Evaluation of Rezafungin Provisional CLSI Clinical Breakpoints and Epidemiological Cutoff Values Tested against a Worldwide Collection of Contemporaneous Invasive Fungal Isolates (2019 to 2020).

Rezafungin is a new echinocandin under development for the treatment of candidemia and invasive candidiasis. CLSI recently approved provisional susceptible-only breakpoints and epidemiological cutoff values for Candida spp. and rezafungin. The activities of rezafungin and comparators against 2019 to 2020 invasive fungal isolates was evaluated by applying the new CLSI breakpoints. Rezafungin demonstrated potent activity against Candida albicans (MIC50/MIC90, 0.03/0.06 mg/L; 100.0% susceptible), Candida tropicalis (MIC50/MIC90, 0.03/0.06 mg/L; 100% susceptible), Candida glabrata (MIC50/MIC90, 0.06/0.06 mg/L; 98.3% susceptible), Candida krusei (MIC50/MIC90, 0.03/0.03 mg/L; 100% susceptible), and Candida dubliniensis (MIC50/MIC90, 0.06/0.12 mg/L; 100% susceptible) when tested by the CLSI broth microdilution method. Rezafungin inhibited 99.6% of Candida parapsilosis isolates (MIC50/MIC90, 1/2 mg/L) at the susceptible breakpoint of ≤2 mg/L. All C. albicans, C. tropicalis, and C. krusei isolates, as well as most C. glabrata (96.2% to 97.9%) and C. parapsilosis (86.2% to 100%) isolates, were susceptible to comparator echinocandins. Fluconazole resistance was detected among 0.5%, 4.5%, 10.5%, and 1.2% of C. albicans, C. glabrata, C. parapsilosis, and C. tropicalis isolates, respectively. All echinocandins displayed limited activity against Cryptococcus neoformans. Rezafungin and other echinocandins were active against Aspergillus fumigatus (minimum effective concentration for 90% of isolates tested [MEC90] range, 0.015 to 0.06 mg/L) and Aspergillus section Flavi (MEC90 range, 0.015 to 0.03 mg/L). All but 16 (8.6%) A. fumigatus isolates were susceptible to voriconazole, and 100% of Aspergillus section Flavi isolates were WT to mold-active azoles. When applying the CLSI clinical breakpoints, rezafungin displayed high susceptibility rates (>98.0%) against Candida isolates from invasive fungal infections and showed potent activity against Aspergillus isolates.

Dose-dependent effect of cyclophosphamide treatment on actin

The actin is the essential unit protein of cytoskeleton and muscle sarcomeres. The continuous management of filaments is the key machinery of eukaryotic cytoskeletal plasticity which based on the different complexes with divalent cations (Ca2+ or Mg2+) and nucleotides (ATP, ADP). Any structural modification of nucleotide-binding sites in G actin can bind ATP or ADP under different cation conditions and can initialize the remodelling of the cleft and change the stiffness of two main domains. The evolutionary important nucleotide-binding cleft as a bridge between the two domains needs more investigation to can express its importance in the development of actin functions. The cyclophosphamide (CP) is a cytostatic drug applied in chemotherapy it can alkylate the long residues in the ATP binding sites thus change the structure of the binding cleft. Our previous study explained that the actin filaments show less sensitivity to the CP treatment than monomers. Here we investigate the CP dose-response effect on the thermodynamic stability of actin monomers and polymers in the presence of Ca2+ or Mg2+ to know the minimum effective concentration for the interpretation of any relevant dosage at level of tissues. The previously expressed “titled state” EM model of filamentous actin based on the same structural change of monomers as we found here where the domains react to any modification with taking apart sd4 from sd2 results in a more exposed nucleotide-binding cleft.

Removal of Microcystis aeruginosa cells using the dead cells of a marine filamentous bacterium, Aureispira sp. CCB-QB1.

Inorganic and synthetic flocculants are widely investigated for removing harmful microalgae, such as Microcystis aeruginosa. However, their toxicity and non-biodegradability are shortcomings. Bioflocculants based on extracellular polysaccharides have attracted much attention as alternative flocculants. However, its high production cost is a limiting factor for applying bioflocculants. Here, we investigate the potential of the dead cells of a marine filamentous bacterium, Aureispira sp. CCB-QB1, as a novel flocculant on M. aeruginosa cells. The removal efficiency of M. aeruginosa cells by the dead cells was measured by mixing and shaking both components in a buffer with 5 mM CaCl2 in different incubation times and concentrations of the dead cells. After that, the minimum effective concentration of CaCl2 was determined. The combination effect of FeCl3 and the dead cells on the removal efficiency was tested. The structure of cell aggregates consisted of the dead cells and M. aeruginosa cells were also observed using a scanning electron microscope. The maximum removal efficiency (75.39%) was reached within 3 min in the presence of CaCl2 when 5 mg/ml of the dead cells (wet cells) were added. The optimal concentration of CaCl2 was 5 mM. The combination of the dead cells and a low concentration of FeCl3 (10 mg/L) with 5 mM of CaCl2 significantly improved the removal efficiency by about 1.2 times (P < 0.05). This result indicates that the combination usage of the dead cells can reduce the use of FeCl3. These results indicated that the dead cells could potentially be a novel biolfocculant to remove M. aeruginosa cells.

Biocidal activities of Curcuma longa L. against anthracnose of mango fruits caused by Colletotrichum gloeosporioides (Penz.) Penz. and Sacc

This study investigates the biological activities of Curcuma longa L., locally known as “turmeric” against anthracnose of mango fruits caused by Colletotrichum gloeosporioides. The results showed that the minimum effective concentration of turmeric crude extract (TCE) was 2.0 g/L, and can be applied as curative, simultaneous and preventative treatment on mango fruits to inhibit the anthracnose infection. TCE also affects the growth and development of C. gloeosporioides by damaging the morphological structure of spores and mycelia. Further, the toxicity of TCE was comparatively superior to conventional synthetic fungicide (Mancozeb 80) in the market terms of potency and efficacy of compound. Twenty-three chemical components were identified in TCE, based on gas chromatography and mass spectrometry analysis. The four major compounds were as follow: aR-turmerone (50.63%), curlone (15.42%), α-curcumene (6.48%), 3-octanol (5.88%). These present findings support the potential use of turmeric crude extract as an alternative to synthetic fungicide.

Design of Oral Sustained-Release Pellets by Modeling and Simulation Approach to Improve Compliance for Repurposing Sobrerol.

Sobrerol, an oral mucolytic agent, in a recent study showed promise for treating multiple sclerosis. A human equivalent dose of 486 mg of sobrerol administered thrice daily (i.e., 1459 mg of daily dose) demonstrated the highest therapeutic efficacy for repurposing use, which also points out the poor compliance of administration. In this study, oral sustained-release pellets of sobrerol were successfully developed with evaluated manufacturing conditions and drug release kinetics. For design of the target drug product, we used a modeling and simulation approach to establish a predictive model of oral pharmacokinetic profile, by exploring the characteristics and correlations corresponding to the pharmacokinetics and pharmacodynamics of sobrerol, such as absorption lag time (0.18 h), time-scaling in vitro–in vivo correlation (tin-vitro = 0.494 tin-vivo − 0.0904), gastrointestinal transit time (8 h), minimum effective concentration (1.61 μg/mL), and duration of action (12.8 h). Results showed that the frequency of administration and the daily dose remarkably reduced by 33.3% (i.e., from thrice to twice daily) and 22.8%, respectively, which indicates that this prototype approach can be adopted for rapidly developing a modified-release dosage form of sobrerol, with improvement of compliance of administration and therapeutic efficacy.

Value of Ultrasonic Image Features in Diagnosis of Perinatal Outcomes of Severe Preeclampsia on account of Deep Learning Algorithm.

This study is aimed at discussing the value of ultrasonic image features in diagnosis of perinatal outcomes of severe preeclampsia on account of deep learning algorithm. 140 pregnant women singleton with severe preeclampsia were selected as the observation group. At the same time, 140 normal singleton pregnant women were selected as the control group. The hemodynamic indexes were detected by color Doppler ultrasound. The CNN algorithm was used to classify ultrasound images of two groups of pregnant women. The differential scanning calorimetry (DSC), mean pixel accuracy (MPA), and mean intersection of union (MIOU) values of CNN algorithm were 0.9410, 0.9228, and 0.8968, respectively. Accuracy, precision, recall, and F1-score were 93.44%, 95.13%, 95.09%, and 94.87%, respectively. The differences were statistically significant (P < 0.05). Compared with the normal control group, the umbilical artery (UA), uterine artery-systolic/diastolic (UTA-S/D), uterine artery (UTA), and digital video (DV) of pregnant women in the observation group were remarkably increased; the minimum alveolar effective concentration (MCA) of the observation group was obviously lower than the MCA of the control group, and the differences between groups were statistically valid (P < 0.05). Logistic regression analysis showed that UA-S/D, UA-resistance index (UA-RI), UTA-S/D, UTA-pulsatility index (UTA-PI), DV-peak velocity index for veins (DV-PVIV), and MCA-S/D were independent risk factors for the outcome of perinatal children with severe preeclampsia. In the perinatal management of severe epilepsy, the combination of the above blood flow indexes to select the appropriate delivery time had positive significance to improve the pregnancy outcome and reduce the perinatal mortality.

Pharmacokinetic Simulation Analysis of Less Frequent Nivolumab and Pembrolizumab Dosing: Pharmacoeconomic Rationale for Dose Deescalation.

Nivolumab and pembrolizumab, anti-programmed cell death protein 1 monoclonal antibodies, have revolutionized oncology but are expensive. Using an interventional pharmacoeconomic approach, these drugs can be administered less often to reduce costs and increase patient convenience while maintaining efficacy. Both drugs are good candidates for less frequent dosing because of long half-lives and no evidence of a relationship of dose to efficacy. Established population pharmacokinetic models for both nivolumab and pembrolizumab were used to simulate profiles for multiple dosing regimens on 1000 randomly generated virtual patients. Simulations were initially performed on standard dose regimens to validate these in silico predictions. Next, simulations of nivolumab 0.3 mg/kg every 3 weeks revealed that >95% of patients maintained ≥1.5 μg/mL at steady state, which was inferred as the minimum effective concentration (MEC) for both drugs. Various alternative dosing regimens were simulated for both drugs to determine which regimen(s) can maintain this MEC in >95% of patients. Extended dosing regimens of nivolumab 240 mg every 4weeks and 480 mg every 8 weeks along with pembrolizumab 200 mg every 6 weeks were simulated, showing that >95% of patients maintained MEC or greater. These simulations demonstrate the potential to reduce drug exposure by at least 50%, thus substantially reducing patient visits (as well as costs), while maintaining equivalent efficacy. These models provide the scientific justification for an ongoing prospective randomized clinical trial comparing standard interval fixed dosing with extended interval fixed dosing, and ultimately an efficacy-driven comparative trial.

Minimum effective concentration of ropivacaine for ultrasound-guided adductor canal + IPACK block in total knee arthroplasty.

This study aimed to investigate the minimum effective concentration (MEC90, defined as effective in 90% of patients) of ropivacaine during the combined procedure of adductor canal block (ACB) and infiltration between the popliteal artery and capsule of the posterior knee (IPACK) block for patients undergoing total knee arthroplasty. This double-blind, randomized dose-finding trial was based on a biased coin up-and-down sequential design, where the concentration of ropivacaine administered to a given patient depended on the previous patient's response. Before surgery, the first patient received 20mL of 0.2% ropivacaine for ACB and again for IPACK. If the block failed, the next subject received a 0.025% higher ropivacaine concentration; otherwise, the next subject received either a 0.025% smaller dose (probability of 0.11) or the same dose (probability of 0.89). The primary outcome was whether the block was successful. Block success was defined as the patient did not suffer significant pain and did not receive rescue analgesia within 6 h after surgery. MEC90 was estimated by isotonic regression, and the 95% confidence interval (CI) was calculated by bootstrapping. Secondary outcomes were numerical rating scale (NRS) pain scores at postoperative 24 h and 48 h, postoperative morphine consumption, and time to hospital discharge. Secondary outcomes were compared between patients whose blocks succeeded with those which failed. Based on analysis of 52 patients, the MEC90 was 0.247% (95% CI 0.227-0.271%), MEC95 was 0.260% (95% CI 0.244-0.282%) and MEC99 was 0.272% (95% CI 0.260-0.291%). In contrast, four of nine trials in a recent systematic review reported ropivacaine concentrations below 0.247%. Patients whose blocks succeeded (n = 45) had significantly lower NRS pain scores, lower morphine consumption, and shorter hospitalization than patients whose blocks failed (n = 7). Our small trial suggests that 0.247% ropivacaine in 20mL respectively can provide successful ACB + IPACK block in 90% of patients. However, given that many published trials have used lower concentrations, our findings should be verified in larger studies.