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Left ventricular anatomic substrates predisposing the development of congestive heart failure in infants with atrial left-to-right shunting after aortic coarctation repair were characterized. Mitral valve, but not aortic or left ventricular, hypoplasia correlated with the development of heart failure and the need for atrial defect closure shortly after coarctation repair. [ABSTRACT FROM AUTHOR]

Infections by Staphylococcus aureus have been treated historically with β-lactam antibiotics. However, these antibiotics have become obsolete in methicillin-resistant S. aureus by acquisition of the bla and mec operons. The presence of the β-lactam antibiotic is detected by the sensor domains of BlaR and/or MecR, and the information is transmitted to the cytoplasm, resulting in derepression of the antibiotic-resistance genes. We hypothesized that inhibition of the sensor domain would shut down this response system, and β-lactam susceptibility would be restored. An in silico search of 11 million compounds led to a benzimidazole-based hit and, ultimately, to the boronate 4. The X-ray structure of 4 is covalently engaged with the active-site serine of BlaR. Compound 4 potentiates by 16- to 4,096-fold the activities of oxacillin and of meropenem against methicillin-resistant S. aureus strains. The combination of 4 with oxacillin or meropenem shows efficacy in infected mice, validating the strategy., (© 2024. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Clostridioides difficile infection (CDI) is the most lethal of the five CDC urgent public health treats, resulting in 12,800 annual deaths in the United States alone [ Antibiotic Resistance Threats in the United States, 2019 (2019), www.cdc.gov/DrugResistance/Biggest-Threats.html]. The high recurrence rate and the inability of antibiotics to treat such infections mandate discovery of new therapeutics. A major challenge with CDI is the production of spores, leading to multiple recurrences of infection in 25% of patients [C. P. Kelly, J. T. LaMont,  N. Engl. J. Med. 359 , 1932-1940 (2008)], with potentially lethal consequence. Herein, we describe the discovery of an oxadiazole as a bactericidal anti- C. difficile agent that inhibits both cell-wall peptidoglycan biosynthesis and spore germination. We document that the oxadiazole binds to the lytic transglycosylase SleC and the pseudoprotease CspC for prevention of spore germination. SleC degrades the cortex peptidoglycan, a critical step in the initiation of spore germination. CspC senses germinants and cogerminants. Binding to SleC is with higher affinity than that to CspC. Prevention of spore germination breaks the nefarious cycles of CDI recurrence in the face of the antibiotic challenge, which is a primary cause of therapeutic failure. The oxadiazole exhibits efficacy in a mouse model of recurrent CDI and holds promise in clinical treatment of CDI.

Pressure ulcers (PUs) are chronic wounds that lead to amputations and death. Little is known about why PUs are recalcitrant to healing. Wound healing is mediated by matrix metalloproteinases (MMPs). The 24 MMPs in humans each exist in three forms, of which only one is catalytically competent. We analyzed human PU samples using an affinity resin that exclusively binds to the catalytically competent MMPs. We identified by mass spectrometry the active forms of MMP-1, MMP-8, MMP-9, and MMP-14. Concentrations of MMP-8, MMP-9, and MMP-14 were higher in human PUs compared to the healthy tissue, whereas those for MMP-1 did not change. Decreasing levels of active MMP-9 as the PU improved argued for a detrimental role for this enzyme. In a mouse model of PUs, a highly selective inhibitor for MMP-9 and MMP-14, ( R )-ND-336, accelerated wound closure in parallel with significant amelioration of ulcer stage. ( R )-ND-336 holds promise as a first-in-class treatment for PUs.

Clostridioides difficile is a leading health threat. This pathogen initiates intestinal infections during gut microbiota dysbiosis caused by oral administration of antibiotics. C. difficile is difficult to eradicate due to its ability to form spores, which are not susceptible to antibiotics. To address the urgent need for treating recurrent C. difficile infection, antibiotics that selectively target C. difficile over common gut microbiota are needed. We herein describe the class of picolinamide antibacterials which show potent and selective activity against C. difficile . The structure-activity relationship of 108 analogues of isonicotinamide 4 , a compound that is equally active against methicillin-resistant Staphylococcus aureus and C. difficile , was investigated. Introduction of the picolinamide core as exemplified by analogue 87 resulted in exquisite potency and selectivity against C. difficile . The ability of the picolinamide class to selectively target C. difficile and to prevent gut dysbiosis holds promise for the treatment of recurrent C. difficile infection., Competing Interests: The authors declare no competing financial interest., (© 2021 American Chemical Society.)

A major challenge for chemotherapy of bacterial infections is perturbation of the intestinal microbiota. Clostridioides difficile is a Gram-positive bacterium of the gut that can thrive under this circumstance. Its production of dormant and antibiotic-impervious spores results in chronic disruption of normal gut flora and debilitating diarrhea and intestinal infection. C. difficile is responsible for 12,800 deaths per year in the United States. Here, we report the discovery of 2-(4-(3-(trifluoromethoxy)phenoxy)picolinamido)benzo[ d ]oxazole-5-carboxylate as an antibacterial with potent and selective activity against C. difficile . Its MIC 50 and MIC 90 (the concentration required to inhibit the growth of 50% and 90% of all the tested strains, respectively) values, documented across 101 strains of C. difficile , are 0.12 and 0.25 μg/mL, respectively. The compound targets cell wall biosynthesis, as assessed by macromolecular biosynthesis assays and by scanning electron microscopy. Animals infected with a lethal dose of C. difficile and treated with compound 1 had a similar survival compared to treatment with vancomycin, which is the frontline antibiotic used for C. difficile infection.

Diabetic foot ulcers (DFUs) are a common complication of diabetes that are recalcitrant to healing due to persistent inflammation. The majority of DFUs have bacterial biofilms, with Staphylococcus epidermidis as a predominant bacterium, requiring infection control with antibiotics before treatment of the wound. Matrix metalloproteinases (MMPs) play roles in the pathology and repair of DFUs. However, defining the roles of the 24 human MMPs has been challenging due to the presence of three forms for each MMP, of which only one is catalytically competent, and the lack of convenient methods to distinguish among the three forms of MMPs. Using an affinity resin that binds only to the active forms of MMPs, with identification and quantification by mass spectrometry, we found that infected wounds in mice had increased levels of active MMP-9 compared to uninfected ones, paralleling infected human DFUs. MMP-9 activity prevents diabetic wounds from healing. We evaluated the efficacy of the selective small-molecule MMP-9 inhibitor, ( R )-ND-336, in the infected diabetic mouse model of wound healing and showed that ( R )-ND-336 alone or in combination with the antibiotic linezolid improves wound healing by inhibiting the detrimental MMP-9, mitigating macrophage infiltration to diminish inflammation, and increasing angiogenesis to restore the normal wound healing process. An advantage of this strategy is the ability to administer ( R )-ND-336 concurrently with an antibiotic., Competing Interests: The authors declare the following competing financial interest(s): U.S. Patent 9,604,957, U.S. Patent 9,951,035, U.S. Patent 10,253,103, European Patent 3107905, Japan Patent 6,5,21,995, and China Patent ZL201580023723.6 have been issued for (R)-ND-336.

We report herein the syntheses of 79 derivatives of the 4(3 H )-quinazolinones and their structure-activity relationship (SAR) against methicillin-resistant Staphylococcus aureus (MRSA). Twenty one analogs were further evaluated in in vitro assays. Subsequent investigation of the pharmacokinetic properties singled out compound 73 (( E )-3-(5-carboxy-2-fluorophenyl)-2-(4-cyanostyryl)quinazolin-4(3 H )-one) for further study. The compound synergized with piperacillin-tazobactam (TZP) both in vitro and in vivo in a clinically relevant mouse model of MRSA infection. The TZP combination lacks activity against MRSA, yet it synergized with compound 73 to kill MRSA in a bactericidal manner. The synergy is rationalized by the ability of the quinazolinones to bind to the allosteric site of penicillin-binding protein (PBP)2a, resulting in opening of the active site, whereby the β-lactam antibiotic now is enabled to bind to the active site in its mechanism of action. The combination effectively treats MRSA infection, for which many antibiotics (including TZP) have faced clinical obsolescence.

Diabetic foot ulcers are characterized by hypoxia. For many patients, hyperbaric oxygen (HBO) therapy is the last recourse for saving the limb from amputation, for which the molecular basis is not understood. We previously identified the active form of matrix metalloproteinase-9 (MMP-9) as responsible for diabetic foot ulcer's recalcitrance to healing. Transcription of mmp-9 to the inactive zymogen is upregulated during hypoxia. Activation of the zymogen is promoted by proteases and reactive oxygen species (ROS). We hypothesized that the dynamics of these two events might lead to a lowering of active MMP-9 levels in the wounded tissue. We employed the full-thickness excisional db/db mouse model to study wound healing, and treated the mice to 3.0 atm of molecular oxygen for 90 minutes, 5 days per week for 10 days in an HBO research chamber. Treatment with HBO accelerated diabetic wound healing compared to untreated mice, with more completed and extended reepithelialization. We imaged the wounds for ROS in vivo with a luminol-based probe and found that HBO treatment actually decreases ROS levels. The levels of superoxide dismutase, catalase, and glutathione peroxidase-enzymes that turn over ROS-increased after HBO treatment, hence the observation of decreased ROS. Since ROS levels are lowered, we explored the effect that this would have on activation of MMP-9. Quantitative analysis with an affinity resin that binds and pulls down the active MMPs exclusively, coupled with proteomics, revealed that HBO treatment indeed reduces the active MMP-9 levels. This work for the first time demonstrates that diminution of active MMP-9 is a contributing factor and a mechanism for enhancement of diabetic wound healing by HBO therapy., (© 2019 by the Wound Healing Society.)

Matrix metalloproteinases (MMPs) play important roles in wound healing, but attribution of their functions in repair of wounds has been challenging. Commonly used tools such as MMP-knockout mice and zymography often confound analysis, which is complicated further as these enzymes exist in three distinct forms with only one being catalytically competent. With the use of topical exogenously administered recombinant MMP-8 and MMP-13 to diabetic and nondiabetic mouse wounds, we show that these proteinases facilitate wound repair by upregulating IL-6 and increasing neutrophil trafficking with an early onset of inflammation. Furthermore, by spatiotemporal control in the use of a selective MMP-2 inhibitor, along with immunoprecipitation and Western blotting, we provide definitive demonstration that MMP-2 does not affect wound healing, contrary to reports. MMP-2 is found in wounds complexed with TIMPs, which is catalytically incompetent., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)

A structure-activity relationship (SAR) for the oxadiazole class of antibacterials was evaluated by syntheses of 72 analogs and determination of the minimal-inhibitory concentrations (MICs) against the ESKAPE panel of bacteria. Selected compounds were further evaluated for in vitro toxicity, plasma protein binding, pharmacokinetics (PK), and a mouse model of methicillin-resistant Staphylococcus aureus (MRSA) infection. Oxadiazole 72c shows potent in vitro antibacterial activity, exhibits low clearance, a high volume of distribution, and 41% oral bioavailability, and shows efficacy in mouse models of MRSA infection., Competing Interests: The authors declare no competing financial interest., (Copyright © 2019 American Chemical Society.)

The quinazolinones are a new class of antibacterials with in vivo efficacy against methicillin-resistant Staphylococcus aureus (MRSA). The quinazolinones target cell wall biosynthesis and have a unique mechanism of action by binding to the allosteric site of penicillin-binding protein 2a (PBP 2a). We investigated the potential for synergism of a lead quinazolinone with several antibiotics of different classes using checkerboard and time-kill assays. The quinazolinone synergized with β-lactam antibiotics. The combination of the quinazolinone with commercial piperacillin-tazobactam showed bactericidal synergy at sub-MICs of all three drugs. We demonstrated the efficacy of the triple-drug combination in a mouse MRSA neutropenic thigh infection model. The proposed mechanism for the synergistic activity in MRSA involves inhibition of the β-lactamase by tazobactam, which protects piperacillin from hydrolysis, which can then inhibit its target, PBP 2. Furthermore, the quinazolinone binds to the allosteric site of PBP 2a, triggering the allosteric response. This leads to the opening of the active site, which, in turn, binds another molecule of piperacillin. In other words, PBP 2a, which is not normally inhibited by piperacillin, becomes vulnerable to inhibition in the presence of the quinazolinone. The collective effect is the impairment of cell wall biosynthesis, with bactericidal consequence. Two crystal structures for complexes of the antibiotics with PBP 2a provide support for the proposed mechanism of action., (Copyright © 2019 American Society for Microbiology.)

Diabetic foot ulcers (DFUs) are a significant health problem. A single existing FDA-approved drug for this ailment, becaplermin, is not standard-of-care. We previously demonstrated that upregulation of active matrix metalloproteinase (MMP)-9 is the reason that the diabetic wound in mice is recalcitrant to healing and that MMP-8 participates in wound repair. In the present study, we validate the target MMP-9 by identifying and quantifying active MMP-8 and MMP-9 in human diabetic wounds using an affinity resin that binds exclusively to the active forms of MMPs coupled with proteomics. Furthermore, we synthesize and evaluate enantiomerically pure ( R)- and ( S)-ND-336, as inhibitors of the detrimental MMP-9, and show that the ( R)-enantiomer has superior efficacy in wound healing over becaplermin. Our results reveal that the mechanisms of pathology and repair are similar in diabetic mice and diabetic humans and that ( R)-ND-336 holds promise for the treatment of DFUs as a first-in-class therapeutic.

Chronic wounds are a complication of diabetes. Treatment for diabetic foot ulcers is complex with little clinical recourse, resulting in 108,000 lower-limb amputations annually in the United States alone. Matrix metalloproteinases (MMPs) play important roles in the pathology and in the repair of chronic wounds. We previously identified active MMP-8 and MMP-9 in wounds of diabetic mice and determined that MMP-8 accelerates wound repair, while MMP-9 is the culprit for the diabetic wound being refractory to healing. Aclerastide, a peptide analog of angiotensin II, recently failed in phase III clinical trials for treatment of diabetic foot ulcers. We demonstrate herein that treatment of wounds of diabetic mice with aclerastide results in elevated levels of reactive oxygen species and of active MMP-9, which is likely an important contributor to the failure of aclerastide in clinical trials., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The metalloproteinase ADAM10 has been reported as an important target for drug discovery in several human diseases. In this vein, (6 S ,7 S )- N -hydroxy-5-methyl-6-(4-(5-(trifluoromethyl)pyridin-2-yl)piperazine-1-carbonyl)-5-azaspiro[2.5]octane-7-carboxamide (compound 1 ) has been reported as a selective ADAM10 inhibitor. We synthesized this compound and document that it lacks both potency and selectivity in inhibition of ADAM10. This finding necessitated a structure-based computational analysis to investigate potency and selectivity of ADAM10 inhibition. The model that emerged indeed excluded compound 1 as an inhibitor for ADAM10, while suggesting another reported compound, (1 R ,3 S ,4 S )-3-(hydroxycarbamoyl)-4-(4-phenylpiperidine-1-carbonyl)cyclohexyl pyrrolidine-1-carboxylate (compound 2 ), as an ADAM10 selective inhibitor. Compound 2 was synthesized and its potency, and selectivity in inhibition of ADAM10 were documented with a panel of several related enzymes. Pharmacokinetic studies of compound 2 in mice documented that the compound crosses the blood-brain barrier and may be useful as a pharmacological agent or mechanistic tool to delineate the role of ADAM10 in neurological diseases., Competing Interests: The authors declare no competing financial interest.

In order to address the dire need for new antibiotics to treat specific strains of drug resistant Gram-negative bacterial infections, a mixed ligand analog of the natural Acinetobacter baumannii selective siderophore, fimsbactin, was coupled to daptomycin, a Gram-positive only antibiotic. The resulting conjugate 11 has potent activity against multidrug resistant strains of A. baumannii both in vitro and in vivo. The study also indicates that conjugation of siderophores to "drugs" that are much larger than the siderophore (iron transport agent) itself facilitates active uptake that circumvents the normal permeability problems in Gram-negative bacteria. The results demonstrate the ability to extend activity of a normally Gram-positive only antibiotic to create a potent and targeted Gram-negative antibiotic using a bacterial iron transport based sideromycin Trojan horse strategy.

Matrix metalloproteinases (MMPs) have numerous physiological functions and share a highly similar catalytic domain. Differential dynamical information on the closely related human MMP-8, -13, and -14 was integrated onto the benzoxazinone molecular template. An in silico library of 28,099 benzoxazinones was generated and evaluated in the context of the molecular-dynamics information. This led to experimental evaluation of 19 synthesized compounds and identification of selective inhibitors, which have potential utility in delineating the physiological functions of MMPs. Moreover, the approach serves as an example of how dynamics of closely related active sites may be exploited to achieve selective inhibition by small molecules and should find applications in other enzyme families with similar active sites.

Matrix metalloproteinase (MMP)-2 knockout (KO) mice show impaired neurological recovery after spinal cord injury (SCI), suggesting that this proteinase is critical to recovery processes. However, this finding in the KO has been confounded by a compensatory increase in MMP-9. We synthesized the thiirane mechanism-based inhibitor ND-378 and document that it is a potent (nanomolar) and selective slow-binding inhibitor of MMP-2 that does not inhibit the closely related MMP-9 and MMP-14. ND-378 crosses the blood-spinal cord barrier, achieving therapeutic concentrations in the injured spinal cord. Spinal-cord injured mice treated with ND-378 showed no change in long-term neurological outcomes, suggesting that MMP-2 is not a key determinant of locomotor recovery.

The oxadiazole antibacterials target the bacterial cell wall and are bactericidal. We investigated the synergism of ND-421 with the commonly used β-lactams and non-β-lactam antibiotics by the checkerboard method and by time-kill assays. ND-421 synergizes well with β-lactam antibiotics, and it also exhibits a long postantibiotic effect (4.7 h). We also evaluated the in vivo efficacy of ND-421 in a murine neutropenic thigh infection model alone and in combination with oxacillin. ND-421 has in vivo efficacy by itself in a clinically relevant infection model (1.49 log10 bacterial reduction for ND-321 versus 0.36 log10 for linezolid with NRS119) and acts synergistically with β-lactam antibiotics in vitro and in vivo, and the combination of ND-421 with oxacillin is efficacious in a mouse neutropenic thigh methicillin-resistant Staphylococcus aureus (MRSA) infection model (1.60 log10 bacterial reduction). The activity of oxacillin was potentiated in the presence of ND-421, as the strain would have been resistant to oxacillin otherwise., (Copyright © 2016, American Society for Microbiology. All Rights Reserved.)

Here, we report the synthesis and evaluation of dual drug-loaded nanoparticles as an effective means to deliver carfilzomib and doxorubicin to multiple myeloma tumor cells at their optimal synergistic ratio. First, various molar ratios of carfilzomib to doxorubicin were screened against multiple myeloma cell lines to determine the molar ratio that elicited the greatest synergy using the Chou-Talalay method. The therapeutic agents were then incorporated into liposomes at the optimal synergistic ratio of 1:1 to yield dual drug-loaded nanoparticles with a narrow size range of 115 nm and high reproducibility. Our results demonstrated that the dual drug-loaded liposomes exhibited synergy in vitro and were more efficacious in inhibiting tumor growth in vivo than a combination of free drugs, while at the same time reducing systemic toxicity. Taken together, this study presents the synthesis and preclinical evaluation of dual drug-loaded liposomes containing carfilzomib and doxorubicin for enhanced therapeutic efficacy to improve patient outcome in multiple myeloma. Mol Cancer Ther; 15(7); 1452-9. ©2016 AACR., (©2016 American Association for Cancer Research.)

We recently reported on the discovery of a novel antibacterial (2) with a 4(3H)-quinazolinone core. This discovery was made by in silico screening of 1.2 million compounds for binding to a penicillin-binding protein and the subsequent demonstration of antibacterial activity against Staphylococcus aureus. The first structure-activity relationship for this antibacterial scaffold is explored in this report with evaluation of 77 variants of the structural class. Eleven promising compounds were further evaluated for in vitro toxicity, pharmacokinetics, and efficacy in a mouse peritonitis model of infection, which led to the discovery of compound 27. This new quinazolinone has potent activity against methicillin-resistant (MRSA) strains, low clearance, oral bioavailability and shows efficacy in a mouse neutropenic thigh infection model.

The gelatinases, matrix metalloproteinases (MMP)-2 and MMP-9, are thought to be key mediators of secondary damage in adult animal models of brain injury. Moreover, an acute increase in these proteases in plasma and brain extracellular fluid of adult patients with moderate-to-severe traumatic brain injuries (TBIs) is associated with poorer clinical outcomes and mortality. Nonetheless, their involvement after TBI in the pediatric brain remains understudied. Using a murine model of TBI at postnatal day 21 (p21), approximating a toddler-aged child, we saw upregulation of active and pro-MMP-9 and MMP-2 by gelatin zymography at 48 h post-injury. We therefore investigated the role of gelatinases on long-term structural and behavioral outcomes after injury after acute inhibition with a selective gelatinase inhibitor, p-OH SB-3CT. After systemic administration, p-OH SB-3CT crossed the blood-brain barrier at therapeutically-relevant concentrations. TBI at p21 induced hyperactivity, deficits in spatial learning and memory, and reduced sociability when mice were assessed at adulthood, alongside pronounced tissue loss in key neuroanatomical regions. Acute and short-term post-injury treatment with p-OH SB-3CT did not ameliorate these long-term behavioral, cognitive, or neuropathological deficits as compared to vehicle-treated controls, suggesting that these deficits were independent of MMP-9 and MMP-2 upregulation. These findings emphasize the vulnerability of the immature brain to the consequences of traumatic injuries. However, early upregulation of gelatinases do not appear to be key determinants of long-term recovery after an early-life injury.

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most prevalent multidrug-resistant pathogens worldwide, exhibiting increasing resistance to the latest antibiotic therapies. Here we show that the triple β-lactam combination meropenem-piperacillin-tazobactam (ME/PI/TZ) acts synergistically and is bactericidal against MRSA subspecies N315 and 72 other clinical MRSA isolates in vitro and clears MRSA N315 infection in a mouse model. ME/PI/TZ suppresses evolution of resistance in MRSA via reciprocal collateral sensitivity of its constituents. We demonstrate that these activities also extend to other carbapenem-penicillin-β-lactamase inhibitor combinations. ME/PI/TZ circumvents the tight regulation of the mec and bla operons in MRSA, the basis for inducible resistance to β-lactam antibiotics. Furthermore, ME/PI/TZ subverts the function of penicillin-binding protein-2a (PBP2a) via allostery, which we propose as the mechanism for both synergy and collateral sensitivity. Showing in vivo activity similar to that of linezolid, ME/PI/TZ demonstrates that combinations of older β-lactam antibiotics could be effective against MRSA infections in humans.

SB-3CT is a potent and selective inhibitor of matrix metalloproteinase (MMP)-2 and -9, which has shown efficacy in an animal model of severe traumatic brain injury (TBI). However, SB-3CT is poorly water-soluble and is metabolized primarily to p-hydroxy SB-3CT (2), a more potent inhibitor than SB-3CT. We synthesized the O-phosphate prodrug (3) of compound 2 to enhance its water solubility by more than 2000-fold. The prodrug 3 was a poor MMP inhibitor, but readily hydrolyzed to the active 2 in human blood. Pharmacokinetics and brain distribution studies in mice showed that 2 crossed the blood-brain barrier (BBB) and achieved therapeutic concentrations in the brain. The prodrug 3/compound 2 was evaluated in a mouse model of severe TBI and found to significantly decrease the brain lesion volume and improve neurological outcomes. MMP-9 inhibition by a water-soluble thiirane inhibitor is a promising therapy for treatment of TBI.

The structure-activity relationship (SAR) for the newly discovered oxadiazole class of antibiotics is described with evaluation of 120 derivatives of the lead structure. This class of antibiotics was discovered by in silico docking and scoring against the crystal structure of a penicillin-binding protein. They impair cell-wall biosynthesis and exhibit activities against the Gram-positive bacterium Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA) and vancomycin-resistant and linezolid-resistant S. aureus. 5-(1H-Indol-5-yl)-3-(4-(4-(trifluoromethyl)phenoxy)phenyl)-1,2,4-oxadiazole (antibiotic 75b) was efficacious in a mouse model of MRSA infection, exhibiting a long half-life, a high volume of distribution, and low clearance. This antibiotic is bactericidal and is orally bioavailable in mice. This class of antibiotics holds great promise in recourse against infections by MRSA.

In the face of the clinical challenge posed by resistant bacteria, the present needs for novel classes of antibiotics are genuine. In silico docking and screening, followed by chemical synthesis of a library of quinazolinones, led to the discovery of (E)-3-(3-carboxyphenyl)-2-(4-cyanostyryl)quinazolin-4(3H)-one (compound 2) as an antibiotic effective in vivo against methicillin-resistant Staphylococcus aureus (MRSA). This antibiotic impairs cell-wall biosynthesis as documented by functional assays, showing binding of 2 to penicillin-binding protein (PBP) 2a. We document that the antibiotic also inhibits PBP1 of S. aureus, indicating a broad targeting of structurally similar PBPs by this antibiotic. This class of antibiotics holds promise in fighting MRSA infections.

Carfilzomib, a recently FDA-approved proteasome inhibitor, has remarkable anti-myeloma (MM) activity. However, its effectiveness is limited by associated severe side-effects, short circulation half-life, and limited solubility. Here, we report the engineering of liposomal carfilzomib nanoparticles to overcome these problems and enhance the therapeutic efficacy of carfilzomib by increasing tumoral drug accumulation while decreasing systemic toxicity. In our design, carfilzomib was loaded into the bilayer of liposomes to yield stable and reproducible liposomal nanoparticles. Liposomal carfilzomib nanoparticles were efficiently taken up by MM cells, demonstrated proteasome inhibition, induced apoptosis, and exhibited enhanced cytotoxicity against MM cells. In vivo, liposomal carfilzomib demonstrated significant tumor growth inhibition and dramatically reduced overall systemic toxicity compared to free carfilzomib. Finally, liposomal carfilzomib demonstrated enhanced synergy in combination with doxorubicin. Taken together, this study establishes the successful synthesis of liposomal carfilzomib nanoparticles that demonstrates improved therapeutic index and the potential to improve patient outcome in MM., (Copyright © 2014 Elsevier B.V. All rights reserved.)

In this study, we describe the development of liposomal bortezomib nanoparticles, which was accomplished by synthesizing bortezomib prodrugs with reversible boronic ester bonds and then incorporating the resulting prodrugs into the nanoparticles via surface conjugation. Initially, several prodrug candidates were screened based upon boronic ester stability using isobutylboronic acid as a model boronic acid compound. The two most stable candidates were then selected to create surface conjugated bortezomib prodrugs on the liposomes. Our strategy yielded stable liposomal bortezomib nanoparticles with a narrow size range of 100 nm and with high reproducibility. These liposomal bortezomib nanoparticles demonstrated significant proteasome inhibition and cytotoxicity against multiple myeloma cell lines in vitro and remarkable tumor growth inhibition with reduced systemic toxicity compared to free bortezomib in vivo. Taken together, this study demonstrates the incorporation of bortezomib into liposomal nanoparticles via reversible boronic ester bond formation to enhance the therapeutic index for improved patient outcome.

Infections caused by hard-to-treat methicillin-resistant Staphylococcus aureus (MRSA) are a serious global public-health concern, as MRSA has become broadly resistant to many classes of antibiotics. We disclose herein the discovery of a new class of non-β-lactam antibiotics, the oxadiazoles, which inhibit penicillin-binding protein 2a (PBP2a) of MRSA. The oxadiazoles show bactericidal activity against vancomycin- and linezolid-resistant MRSA and other Gram-positive bacterial strains, in vivo efficacy in a mouse model of infection, and have 100% oral bioavailability.

Background: Dietary dextrose and fructose may promote vascular inflammation and endothelial dysfunction. In certain infant populations, altered postprandial mesenteric hyperemia (PPH) may increase risk for feeding intolerance., Objective: To compare superior mesenteric artery (SMA) PPH following feeds of lactose-containing (LC) formula vs lactose-free (LF; dextrose + sucrose) formula., Methods: In a 2 × 2 crossover study with 6 term newborns, 3 received LC first followed by LF 3 hours later. The remaining 3 received the reverse order. Ultrasound measures of pre- and postprandial SMA flow, diameter, and resistance were taken 5 minutes preprandial and 10, 30, and 40 minutes postprandial., Results: Mean ± SD age and weight (n = 6) were 24.1 ± 2.3 hours and 3.1 ± 0.21 kg. Formula intake was similar for LC and LF (22.5 ± 2.8 mL and 25 ± 1.8 mL, respectively; P = .076). Both formulas increased SMA flow at 10 and 30 minutes. However, postprandial flow was greater for LC overall (P = .004) and especially at 30 minutes (LC 103 ml/min, 52% increase vs LF 92.7 ml/min, 31% increase; P = .014). For both formulas, vasodilation was seen at 10 and 30 minutes and was overall significantly greater following LC than following LF (9.1% VS 6.5%; P = .028). Both formulas elicited significant decreases in sma vascular resistance over the 10- to 30-minute period (overall P = .016). However, decreases did not differ across formulas (P = .672)., Conclusions: The LC formula elicited a greater SMA PPH response than did LF. SMA flow for both formulas was within normal limits; thus, differences are likely inconsequential for a term newborn. However, in a vulnerable preterm infant, differences may become significant.

Patient: Male, 2 FINAL DIAGNOSIS: Obstructive hypertrophic cardiomyopathy Symptoms: Congestive heart failure Medication: - Clinical Procedure: Left ventricular septal myectomy • repair of congenital heart disease Specialty: Cardiology., Objective: Rare disease., Background: Hypertrophic cardiomyopathy (HCM) is uncommon in Down syndrome (DS). When combined with congenital heart disease (CHD) both morbidity and mortality may be greater compared to CHD alone. Whether HCM in DS patients is related to having trisomy 21 versus a second site mutation is unknown., Case Report: We report a case of severe HCM in an infant with DS in combination with double outlet right ventricle (DORV) who required surgery for relive of sub-aortic obstruction and congestive heart failure. We predicted that this infant would have a second site mutation involving either a sarcomeric protein or metabolic disorder as a cause for his HCM. Using current genetic and metabolic testing as well as histologic assessment of excised cardiac tissue we sought to further characterize the nature of the HCM. A successful resection of sub-aortic stenosis and DORV repair was performed. Genetic and metabolic testing was negative for gene defects and/or syndromes commonly associated with familial HCM. Excised cardiac tissue from the ventricular septum exhibited myocyte hypertrophy and sub-endocardial fibrosis but no sarcomeric disarray, myocyte fibrosis or glycogen storage. Metabolic testing for common forms of mitochondrial disease was negative. Post-operative echocardiograms show persistent, non-obstructive septal hypertrophy., Conclusions: Unlike prior reports, this child required a surgical intervention to relieve his sub-aortic obstruction. Thus, HCM in this population can be more serious that previously suspected. Although testing did not reveal the cause of his HCM, we still suggest screening for known causes of HSC until the etiology of the HCM in DS is well understood.

Brain metastasis occurs in 20-40% of cancer patients. Treatment is mostly palliative, and the inability of most drugs to penetrate the brain presents one of the greatest challenges in the development of therapeutics for brain metastasis. Matrix metalloproteinase-2 (MMP-2) plays important roles in invasion and vascularization of the central nervous system and represents a potential target for treatment of brain metastasis. Carbonate, O-phenyl carbamate, urea, and N-phenyl carbamate derivatives of SB-3CT, a selective and potent gelatinase inhibitor, were synthesized and evaluated. The O-phenyl carbamate and urea variants were selective and potent inhibitors of MMP-2. Carbamate 5b was metabolized to the potent gelatinase inhibitor 2, which was present at therapeutic concentrations in the brain. In contrast, phenyl urea 6b crossed the blood-brain barrier, however, higher doses would result in therapeutic brain concentrations. Carbamate 5b and urea 6b show potential for intervention of MMP-2-dependent diseases such as brain metastasis.

Traumatic brain injury (TBI) is a leading cause of death and long-term disability. Following the initial insult, severe TBI progresses to a secondary injury phase associated with biochemical and cellular changes. The secondary injury is thought to be responsible for the development of many of the neurological deficits observed after TBI and also provides a window of opportunity for therapeutic intervention. Matrix metalloproteinase-9 (MMP-9 or gelatinase B) expression is elevated in neurological diseases and its activation is an important factor in detrimental outcomes including excitotoxicity, mitochondrial dysfunction and apoptosis, and increases in inflammatory responses and astrogliosis. In this study, we used an experimental mouse model of TBI to examine the role of MMP-9 and the therapeutic potential of SB-3CT, a mechanism-based gelatinase selective inhibitor, in ameliorating the secondary injury. We observed that activation of MMP-9 occurred within one day following TBI, and remained elevated for 7 days after the initial insult. SB-3CT effectively attenuated MMP-9 activity, reduced brain lesion volumes and prevented neuronal loss and dendritic degeneration. Pharmacokinetic studies revealed that SB-3CT and its active metabolite, p-OH SB-3CT, were rapidly absorbed and distributed to the brain. Moreover, SB-3CT treatment mitigated microglial activation and astrogliosis after TBI. Importantly, SB-3CT treatment improved long-term neurobehavioral outcomes, including sensorimotor function, and hippocampus-associated spatial learning and memory. These results demonstrate that MMP-9 is a key target for therapy to attenuate secondary injury cascades and that this class of mechanism-based gelatinase inhibitor-with such desirable pharmacokinetic properties-holds considerable promise as a potential pharmacological treatment of TBI.

MMP-9 plays a detrimental role in the pathology of several neurological diseases and, thus, represents an important target for intervention. The water-soluble prodrug ND-478 is hydrolyzed to the active MMP-9 inhibitor ND-322, which in turn is N-acetylated to the even more potent metabolite ND-364. We used a sensitive bioanalytical method based on ultraperformance liquid chromatography with multiple-reaction monitoring detection to measure levels of ND-478, ND-322, and ND-364 in plasma and brain after administration of ND-478 and the metabolites. ND-478 did not cross the blood-brain barrier, as was expected; however the active metabolites ND-322 and ND-364 distributed to the brain. The active compound after administration of either ND-478 or ND-322 is likely ND-364. ND-322 is N-acetylated in both brain and liver, but it is so metabolized preferentially in liver. Since N-acetyltransferases involved in the metabolism of ND-322 to ND-364 are polymorphic, direct administration of the N-acetylated ND-364 would achieve the requisite therapeutic levels in the brain.

SB-3CT, a potent and selective inhibitor of matrix metalloproteinase-2 and -9, has shown efficacy in several animal models of neurological diseases. One of the greatest challenges in the development of therapeutics for neurological diseases is the inability of drugs to cross the blood-brain barrier. A sensitive bioanalytical method based on ultraperformance liquid chromatography with multiple-reaction monitoring detection was developed to measure levels of SB-3CT, its active metabolite, the α-methyl analogue, and its p-hydroxy metabolite in plasma and brain. The compounds are rapidly absorbed and are readily distributed to the brain. The pharmacokinetic properties of these gelatinase inhibitors and the efficacy shown by SB-3CT in animal models of stroke, subarachnoid hemorrhage, and spinal cord injury indicate that this class of compounds holds considerable promise in the treatment of diseases of the central nervous system.

SB-3CT (1), a selective and potent thiirane-based gelatinase inhibitor, is effective in animal models of cancer metastasis and stroke; however, it is limited by poor aqueous solubility and extensive metabolism. We addressed these issues by blocking the primary site of metabolism and capitalizing on a prodrug strategy to achieve >5000-fold increased solubility. The amide prodrugs were quantitatively hydrolyzed in human blood to a potent gelatinase inhibitor, ND-322 (3). The arginyl amide prodrug (ND-478, 5d) was metabolically stable in mouse, rat, and human liver microsomes. Both 5d and 3 were nonmutagenic in the Ames II mutagenicity assay. The prodrug 5d showed moderate clearance of 0.0582 L/min/kg, remained mostly in the extracellular fluid compartment (Vd = 0.0978 L/kg), and had a terminal half-life of >4 h. The prodrug 5d had superior pharmacokinetic properties than those of 3, making the thiirane class of selective gelatinase inhibitors suitable for intravenous administration in the treatment of acute gelatinase-dependent diseases.

Objective: Intracardiac arteriovenous malformations are rare and may be associated with sudden death in adults. This case report describes an intracardiac left coronary arteriovenous malformation in a 7-year-old boy with a suspected familial cutaneous vascular malformation syndrome. The patient presented with a diastolic murmur, exercise intolerance, chest pain, and a left ventricular mass., Methods: The left ventricular mass was initially identified by echocardiography. Subsequently, a computed tomography scan revealed the vascular nature of the lesion. We hypothesized that the lesion represented either an arteriovenous malformation (AVM) or a hemangioma. These lesions are thought to cause coronary steal and myocardial dysfunction. Skin biopsies of the patient's cutaneous lesions revealed capillary hyperplasia, which was not consistent with either hemangioma or AVM. Thus, a surgical biopsy and partial resection of the mass was performed., Results: The surgical pathology of the cardiac mass was consistent with an AVM. Within 6 months following partial resection of the mass, the patient unexpectedly developed a left ventricular pseudoaneurysm at the resection site and required re-operation. Although a portion of the mass remains, both the patient's chest pain and exercise tolerance have improved subjectively., Conclusion: Patients with cutaneous vascular malformations and diastolic murmurs, as well as cardiac symptoms, should undergo echocardiography or alternative imaging modalities to screen for treatable pathological myocardial vascular malformations.

Propionic acidemia and long QT syndrome (LQTS) are rare disorders. In addition, both conditions are potentially lethal. The patient presented in this article was initially diagnosed with propionic acidemia. Incidentally, she was found to have LQTS on electrocardiogram and verified by stress test and epinephrine challenge. Although the patient was asymptomatic and arrhythmia free, we started her on atenolol. This is the first report of the association between LQTS and propionic acidemia.

Objective: To determine the incidence of catheter-related surgical emergencies during pediatric interventional catheterization procedures., Study Design: We reviewed all interventional catheter procedures (n = 578) over a 4-year period (April 1996 to April 2000) to determine any complication during interventional catheterization that required surgery within 24 hours after catheterization., Results: The overall incidence of surgical emergencies was 1.9% (70% confidence limits, 1.5% to 2.7%). Complications that required surgical intervention occurred with balloon dilation (valvuloplasty, angioplasty, n = 4), device deployment (coils, stents, atrial-septal defect devices, n = 5), transhepatic access (n = 1), and atrial transseptal puncture (n = 1). For the majority of interventions, the incidence of surgical emergencies was <4% except for two procedures (conduit and pulmonary artery angioplasty) with limited numbers of patients. There were no surgical emergencies during endomyocardial biopsy, coarctation angioplasty, or balloon atrial septostomy., Conclusions: Surgery was required in 1.9% of all interventional catheter procedures. Surgical emergencies occurred during a wide variety of catheter interventions and could not be predicted by the type of procedure performed.

The Streptococcus mutans extracellular fructosyltransferase (FTF) enzyme may play a role in the formation of dental caries by synthesizing a fructan polymer that serves as an extracellular storage polysaccharide. We sought to determine if an FTF-deficient strain of S. mutans was less virulent than wild-type cells in a rat animal model system. Cloned ftf gene sequences from S. mutans GS5 were used to generate a defective copy of the ftf gene by inserting into the ftf coding region a DNA fragment which encoded erythromycin resistance. The plasmid which carried the defective ftf construct was introduced into S. mutans V403 by using genetic transformation. This defective construct replaced, by allelic exchange, the wild-type copy of the ftf gene carried on the V403 chromosome. FTF activity assays indicated that the recombinant strain, V1741, was deficient in fructan synthesis. However, extracellular protein preparations from this strain displayed an increased ability to generate glucose polymers (glucans) compared with V403 preparations. Levels of adherence to glass and rat tooth surfaces by strain V1741 were similar to those of the V403 strain. Both strains caused moderate decay on rat tooth surfaces; however, the FTF-deficient strain was less pathogenic compared with the wild-type strain. These results suggest that FTF activity contributes to the pathogenicity of S. mutans V403, possibly by generating extracellular fructans which serve as storage compounds.