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1.
Lancet ; 403(10434): 1351-1361, 2024 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-38490230

RESUMO

BACKGROUND: The current standard of care of screening and referring patients for treatment for symptoms, such as depression, pain, and fatigue, is not effective. This trial aimed to test the efficacy of an integrated screening and novel stepped collaborative care intervention versus standard of care for patients with cancer and at least one of the following symptoms: depression, pain, or fatigue. METHODS: This randomised, parallel, phase 3 trial was conducted in 29 oncology outpatient clinics associated with the UPMC Hillman Cancer Center in the USA. Patients (aged ≥21 years) with any cancer type and clinical levels of depression, pain, or fatigue (or all of these) were eligible. Eligible family caregivers were aged 21 years or older and providing care to a patient diagnosed with cancer who consented for this study. Patients were randomly assigned (1:1) to stepped collaborative care or standard of care using a central, permuted block design (sizes of 2, 4, and 6) stratified by sex and prognostic status. The biostatistician, oncologists, and outcome assessors were masked to treatment assignment. Stepped collaborative care was once-weekly cognitive behavioural therapy for 50-60 min from a care coordinator via telemedicine (eg, telephone or videoconferencing). Pharmacotherapy for symptoms might be initiated or changed if recommended by the treatment team or preferred by the patient. Standard of care was screening and referral to a health-care provider for treatment of symptoms. The primary outcome was health-related quality of life in patients at 6 months. Maintenance of the treatment benefits was assessed at 12 months. Participants included in the primary analysis were per intention to treat, which included patients missing one or both follow-up assessments. This trial was registered with ClinicalTrials.gov (NCT02939755). FINDINGS: Between Dec 5, 2016, and April 8, 2021, 459 patients and 190 family caregivers were enrolled. 222 patients were assigned to standard of care and 237 to stepped collaborative care. Of 459 patients, 201 (44%) were male and 258 (56%) were female. Patients in the stepped collaborative care group had a greater 0-6-month improvement in health-related quality of life than patients in the standard-of-care group (p=0·013, effect size 0·09). Health-related quality of life was maintained for the stepped collaborative care group (p=0·74, effect size 0·01). Patients in the stepped collaborative care group had greater 0-6-month improvements than the standard-of-care group in emotional (p=0·012), functional (p=0·042), and physical (p=0·033) wellbeing. No adverse events were reported by patients in either group and deaths were considered unrelated to the study. INTERPRETATION: An integrated screening and novel stepped collaborative care intervention, compared with the current standard of care, is recommended to improve health-related quality of life. The findings of this study will advance the implementation of guideline concordant care (screening and treatment) and has the potential to shift the practice of screening and treatment paradigm nationwide, improving outcomes for patients diagnosed with cancer. FUNDING: US National Cancer Institute.


Assuntos
Cuidadores , Neoplasias , Feminino , Humanos , Masculino , Fadiga , Neoplasias/diagnóstico , Neoplasias/terapia , Dor , Qualidade de Vida , Resultado do Tratamento , Adulto Jovem , Adulto
2.
Proteins ; 91(9): 1222-1234, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37283297

RESUMO

The RNA-dependent RNA polymerase (RdRp) complex of SARS-CoV-2 lies at the core of its replication and transcription processes. The interfaces between holo-RdRp subunits are highly conserved, facilitating the design of inhibitors with high affinity for the interaction interface hotspots. We, therefore, take this as a model protein complex for the application of a structural bioinformatics protocol to design peptides that inhibit RdRp complexation by preferential binding at the interface of its core subunit nonstructural protein, nsp12, with accessory factor nsp7. Here, the interaction hotspots of the nsp7-nsp12 subunit of RdRp, determined from a long molecular dynamics trajectory, are used as a template. A large library of peptide sequences constructed from multiple hotspot motifs of nsp12 is screened in-silico to determine sequences with high geometric complementarity and interaction specificity for the binding interface of nsp7 (target) in the complex. Two lead designed peptides are extensively characterized using orthogonal bioanalytical methods to determine their suitability for inhibition of RdRp complexation. Binding affinity of these peptides to accessory factor nsp7, determined using a surface plasmon resonance (SPR) assay, is slightly better than that of nsp12: dissociation constant of 133nM and 167nM, respectively, compared to 473nM for nsp12. A competitive ELISA is used to quantify inhibition of nsp7-nsp12 complexation, with one of the lead peptides giving an IC50 of 25µM . Cell penetrability and cytotoxicity are characterized using a cargo delivery assay and MTT cytotoxicity assay, respectively. Overall, this work presents a proof-of-concept of an approach for rational discovery of peptide inhibitors of SARS-CoV-2 protein-protein interactions.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , Peptídeos/farmacologia , Sequência de Aminoácidos , RNA Polimerase Dependente de RNA
3.
Org Biomol Chem ; 21(45): 9054-9060, 2023 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-37937510

RESUMO

The development of artificial molecular machines is a challenging endeavor. Herein, we have synthesized a series of bispidine diamides D1-D6 that exhibit rotation reminiscent of a motor motion. Dynamic NMR, X-ray diffraction, quantum mechanical calculations, and molecular dynamics simulations provided insights into their rotational dynamics. All the diamides D1-D6 exhibited mutually independent rotation around the two bispidine arms. However, the rate of rotation and the presence or absence of directionality in amide bond rotation were found to depend on the solvent, temperature, and nature of substitution on the amide carbonyl. These engineered systems may aid in the development of biologically relevant synthetic molecular motors. Studies on homochiral and heterochiral bispidine-peptides revealed that the direction of rotation can be controlled by chirality and the nature of the amino acid.

4.
Transpl Infect Dis ; 25 Suppl 1: e14072, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37260056

RESUMO

BACKGROUND: Infections by multidrug-resistant organisms (MDRO) are a major hurdle in hematopoietic stem-cell transplants (HSCTs). Conditioning regimens lead to mucosal barrier injury, which in-turn leads to transmigration of gut bacteria and sepsis. Pre-transplant stool and throat surveillance cultures can guide empirical antibiotic policy during the neutropenic period. In this paper, we document colonization with MDRO in pre-transplant surveillance cultures and the correlation with bloodstream infections in HSCT patients and analyze transplant outcomes with respect to these infections. METHODS: A single-center, retrospective study on HSCT was performed between January 2021 and December 2021. The incidence of bacterial infections, percentage of MDROs, correlation with pre-transplant stool/throat surveillance cultures, and their impact on overall 100-day and post-100-day to 6-month post-transplant survival were analyzed. RESULTS: Sixty-four patients were included in the study. Pre-transplant stool surveillance cultures were positive for MDRO in 85.9% of patients. Almost half (48.5%) of the isolates were positive for carbapenemase-producing genes (mainly New Delhi metallo-beta-lactamase-1 [NDM-1] and oxacillinase-48 [OXA-48]). Eighteen patients (18/64, 28%) had a positive blood culture for MDRO in the peri-engraftment neutropenic period. Correlation between surveillance and blood cultures was seen in 61% (11/18) of patients. All-cause mortality was 14.1% (9/64) and 25% (16/64) in patients at 100 days and 6 months post-HSCT, respectively. The 100-day and post-100-day all-cause mortality rates were higher in patients with Gram-negative MDRO bloodstream infections (p < .012 and <.008, respectively). CONCLUSION: MDRO infections can adversely affect HSCT outcomes. Pre-transplant stool and throat surveillance cultures may guide empirical antibiotic policy and lead to favorable transplant outcomes.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Neoplasias , Sepse , Humanos , Farmacorresistência Bacteriana Múltipla , Estudos Retrospectivos , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Sepse/tratamento farmacológico
5.
Am J Otolaryngol ; 44(6): 103975, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37478538

RESUMO

BACKGROUND: COVID-associated Rhino-Orbito-Cerebral Mucormycosis (CAROM) appeared as an epidemic in India during the second wave of the COVID-19 pandemic during the months of March to May 2021. Though many reports have highlighted cross sectional and short-term attributes related to CAROM, long term follow up data is sparse. OBJECTIVE: This report aims to analyze the follow-up outcomes in consecutive patients presenting to us during the epidemic. PATIENTS AND METHODS: This was an ambispective observational analytical study, recruiting the consecutive patients admitted to our tertiary care centre during the period of the CAROM epidemic. The mortality rate during the follow-up and various factors affecting survival were studied using univariable and multivariable statistics with the Stata 14.0 software. RESULTS: Of the 189 patients studied, eight were lost to follow-up. The outcome analysis was performed for the 181 patients. 93.6 % (162/173) of the patients had diabetes. The All-cause mortality was 45 % (81/181), while the ROCM-specific mortality was found to be 24 % (46/181) at a median follow-up of 176 days (IQR: 21-217 days). With univariable analysis, increasing age, higher serum IL-6 levels, presence of additional comorbidities (in addition to Diabetes and hypertension), bilateral disease, skin necrosis, palatal involvement, infratemporal fossa involvement, and impaired vision/ocular movements were found to be associated with increased mortality. However, on multivariable analysis, only 1) increasing age, 2) raised serum IL-6 levels, and 3) bilateral disease were predictive of increased mortality. Surgical debridement (endoscopic, palatal removal, orbital exenteration, neurosurgical intervention) was associated with significantly reduced mortality on both univariable and multivariable analysis. CONCLUSION: Our intermediate-term follow-up data showed advanced age at presentation, raised IL-6 levels, and bilateral sinonasal involvement to be predictive of increased mortality, while surgical debridement is significantly protective from mortality in CAROM patients.


Assuntos
COVID-19 , Diabetes Mellitus , Mucormicose , Doenças Orbitárias , Humanos , Pré-Escolar , Estudos Transversais , Interleucina-6 , Pandemias , Doenças Orbitárias/etiologia
6.
Mol Pharm ; 19(11): 3770-3783, 2022 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-36173709

RESUMO

We have developed a multi-level virtual screening protocol to identify lead molecules from the FDA inactives database that can inhibit insulin aggregation. The method is based on the presence of structural and interaction specificity in non-native aggregation pathway protein-protein interactions. Some key challenges specific to the present problem, when compared with native protein association, include structural heterogeneity of the protein species involved, multiple association pathways, and relatively higher probability of conformational rearrangement of the association complex. In this multi-step method, the inactives database was first screened using the dominant pharmacophore features of previously identified molecules shown to significantly inhibit insulin aggregation nucleation by binding to its aggregation-prone conformers. We then performed ensemble docking of several low-energy ligand conformations on these aggregation-prone conformers followed by molecular dynamics simulations and binding affinity calculations on a subset of docked complexes to identify a final set of five potential lead molecules to inhibit insulin aggregation nucleation. Their effect on aggregation inhibition was extensively investigated by incubating insulin under aggregation-prone aqueous buffer conditions (low pH, high temperature). Aggregation kinetics were characterized using size exclusion chromatography and Thioflavin T fluorescence assay, and the secondary structure was determined using circular dichroism spectroscopy. Riboflavin provided the best aggregation inhibition, with 85% native monomer retention after 48 h incubation under aggregation-prone conditions, whereas the no-ligand formulation showed complete monomer loss after 36 h. Further, insulin incubated with two of the screened inactives (aspartame, riboflavin) had the characteristic α-helical dip in CD spectra, while the no-ligand formulation showed a change to ß-sheet rich conformations.


Assuntos
Ensaios de Triagem em Larga Escala , Insulina , Insulina/química , Ligantes , Estrutura Secundária de Proteína , Insulina Regular Humana , Riboflavina , Dicroísmo Circular
7.
Natl Med J India ; 35(3): 132-137, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36461870

RESUMO

Background There was a dramatic rise in the incidence of rhino-orbito-cerebral mucormycosis associated with the 2021 Covid-19 wave in India. We aim to document the demographic characteristics and risk factors of a consecutive cohort of inpatients with Covid-19-associated rhino-orbito-cerebral mucormycosis (CAROM) during the surge of April-June 2021. Methods We included all patients of CAROM treated at our tertiary referral facility from 1 April to 14 June 2021. We prospectively gathered details with regard to Covid-19 illness and treatment, CAROM presentation, comorbid conditions and risk factors. Results Our prospective cohort consisted of 200 consecutive patients, of which 146 (73%) patients tested positive on the Covid-19 RT-PCR test at presentation. CAROM occurred concurrent with the Covid-19 infection in 86%, and delayed CAROM after seeming recovery from Covid-19 was seen in 14%. Covid-19 was classified as mild, moderate and severe in 54%, 33% and 13%. The surge of CAROM followed the population peak of Covid-19 infections by about 3 weeks. Advanced disease at presentation was frequent with ocular involvement in 56.6% (111/196) and central nervous system involvement in 20% (40/199). One or more comorbid conditions were identified in 191/200 (95.5%) patients. The dominant associations were with diabetes (189/200; 94.5%) and uncontrolled hyper-glycaemia (122/133; 91.7%), recent steroid use (114/ 200; 57%), which was often considered as inappropriate in dosage or duration, lymphopenia (142/176; 80.7%), and increased ferritin levels (140/160; 87.5%). No evidence supported the role of previous oxygen therapy or previous nasal swab testing as risk factors for CAROM. Conclusion The inpatient volumes of CAROM were noted to parallel the Covid-19 incidence curve by about 3 weeks. Covid-19 infection may directly predispose to CAROM by way of lymphopenia and increased ferritin levels. Uncontrolled hyperglycaemia is identified as a near-invariable association. Recent steroid use is noted as very frequent and was often received in excess of treatment advisories.


Assuntos
COVID-19 , Linfopenia , Mucormicose , Humanos , Mucormicose/epidemiologia , Pacientes Internados , Estudos Prospectivos , COVID-19/epidemiologia , Fatores de Risco , Demografia , Ferritinas , Esteroides
8.
Proteins ; 2020 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-32860270

RESUMO

Biosimilars offer an avenue for potential cost savings and enhanced patient access to various emerging therapies in a budget neutral way. Biosimilars of the granulocyte colony stimulating factor (GCSF) are an excellent example in this regard with as many as 18 versions of the drug being currently approved across globe for treatment of neutropenia. Here, we identified oxidation of the various methionine residues in GCSF as a key heterogeneity that adversely impact its efficacy. In agreement with earlier studies, it was found that oxidation of Met 122 and Met 127 significantly contributes toward reduction of GCSF efficacy, measured using binding affinity to the GCSF receptor. The combination of molecular dynamics simulation along with structural characterization studies established that oxidation of Met 127 and Met 122 brings about a small local conformational change around the B-C loop in GCSF structure due to slight displacement of Asp113 and Thr117 residues. The simulation studies were validated using fluorescence quenching experiments using acrylamide as quencher and site-directed mutagenesis by replacing Met 122 and Met 127 residues with alanine. The results of this study lead to an enhanced mechanistic understanding of the oxidation in GCSF and should be useful in protein engineering efforts to design stable, safe, and efficacious GCSF product. In addition, the structure-function information can provide targets for protein engineering during early drug development and setting specifications of allowable limits of product variants in biosimilar products.

9.
J Chem Inf Model ; 60(6): 3304-3314, 2020 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-32323986

RESUMO

We report a structure-based approach to design peptides that can bind to aggregation-prone, partially folded intermediates (PFI) of insulin, thereby inhibiting early stages of aggregation nucleation. We account for the important role of the modular architecture of protein-protein binding interfaces and tertiary structure heterogeneity of the PFIs in the design of peptide inhibitors. The determination of association hotspots revealed that two interface segments are required to capture majority contribution to insulin homodimer binding energy. The selection of peptides that will have a high probability to inhibit insulin self-association was done on the basis of similarity in binding interface coverage of PFI residues in the peptide-PFI complex and the native-PFI dimer. Data on aggregate growth rate and secondary structure for formulations incubated under amyloidogenic conditions show that designed peptides inhibit insulin aggregation in a concentration-dependent manner. The mechanism of aggregation inhibition was probed by determining the enthalpy of peptide-insulin binding and peptide micellization using isothermal titration calorimetry. Finally, the effect of designed peptides on insulin activity was quantified using a spectrophotometric assay for glucose uptake by HepG2 cells.


Assuntos
Peptídeos , Agregados Proteicos , Amiloide , Ligantes , Estrutura Secundária de Proteína
10.
J Environ Manage ; 255: 109914, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32063304

RESUMO

Rapid demographic expansion along with increasing urbanization has aggravated the problem of solid waste management. Therefore, scientists are seeking waste management methods that are eco-friendly, cost effective and produce immediate results. In the developing world, municipal solid waste (MSW) contains mostly organic substances, therefore vermicomposting could be a better and cost-effective option for waste management. In this study, vermicomposting of organic portion of MSW with cow dung (additive) was performed using Eisenia fetida. The results showed significant (p < 0.001) decline in pH (13.17%), TOC (21.70%), C: N (62.53%) and C: P (57.66%) ratios, whilst total N (108.9%), P (84.89%) and K (21.85%) content increased (p < 0.001) in matured vermicompost. Different enzymatic activities declined during termination phase of vermicomposting experiment with maximum decrease of 41.72 (p = 0.002) and 39.56% (p = 0.001) in protease and ß-glucosidase, respectively. FT-IR, TGA, DSC and SEM studies suggested that final vermicompost was more stabilized as compared to initial waste mixture, characterized by reduced levels of aliphatic materials, carbohydrates and increase in aromatic groups possibly due to biosynthesis of humic substances. Both, the conventional (physicochemical and enzyme activity) and advanced techniques depict maturity and stability of the ready vermicompost. However, FT-IR, TGA, DSC and SEM were proved to be more promising, fast and reliable techniques over conventional analyses.


Assuntos
Oligoquetos , Resíduos Sólidos , Animais , Bovinos , Feminino , Substâncias Húmicas , Esterco , Solo , Espectroscopia de Infravermelho com Transformada de Fourier
11.
Langmuir ; 35(45): 14725-14733, 2019 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-31626736

RESUMO

Impedance spectroscopy was used to probe the AC conductivity of extremely dilute colloidal suspensions (2.5 × 10-5 ≤ Φw/v ≤ 4.0 × 10-2) comprising of polystyrene microspheres (PS; κa ≫ 1 and ζ = -65 mV), gold nanoparticles (Au NPs; κa > 1 and ζ = -26 mV), and Au-coated PS metallodielectric particles (Au-PS) in HEPES buffer. When AC electric fields of strength 10 mV and 1 MHz were applied via 100 µm gap interdigitated microelectrodes across 10 µL samples, a highly resistive (θcapacitive < 1°) and nonmonotonic response was obtained with particle concentrations at steady state. While the suspensions were less resistive (than the buffer) below a critical concentration, they became more resistive above it. More interestingly, particle-particle interactions took place in suspensions with concentrations as low as 0.005% w/v. We believe this unique behavior is linked to the ion size asymmetry in the HEPES molecule that provides an ideal microenvironment for counterionic polarization around the particles. The exact mechanism of polarization in HEPES, however, still remains elusive as the current theoretical models for simple electrolytes fail to explain our data.

16.
Int J Gynecol Cancer ; 29(3): 605-612, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30833445

RESUMO

OBJECTIVE: Information on the benefits of enhanced recovery after surgery (ERAS) when applied to advanced ovarian cancer() is minimal. The study objectives were to prospectively evaluate whether the implementation of ERAS in AOC patients improves post-operative recovery, and reduces the length of hospital stay (LOHS), without increasing the readmission rate or surgery-related complications; and to investigate ERAS protocol compliance. METHODS: This was a prospective interventional study carried out at a single university teaching hospital. Patients undergoing laparotomy for advanced ovarian cancer (stages IIb-IV) from March 2017 to February 2018 were managed using an ERAS protocol. The conventional management (CM) period extended from January 2016 to December 2016. The primary outcome was reduction in LOHS. Secondary outcomes were ERAS protocol compliance, incidence of post-operative complications, and readmission rate. RESULTS: The CM and ERAS groups each comprised 45 patients. Both the groups were comparable in terms of clinicopathological and operative characteristic. Median LOHS of the full cohort, primary debulking cohort, interval debulking cohort, staging surgery cohort (all 6 vs 4 days; p<0.001), and complex cytoreductive surgery cohort (5 vs 4 days; p=0.019) were significantly reduced in the ERAS group. The overall compliance for the ERAS protocol was 90.6%. Occurrence of moderate or severe (17.8% vs 0%; p=0.003) and ≥grade 2 extended Clavein-Dindo complications (22.2% vs 0%; p=0.001); and hospital stay due to occurrence of complications (31.1% vs 2.2%; p<0.001) were also significantly reduced in the ERAS group. There was no difference in the 30-day readmission rates. CONCLUSION: The results from our investigation suggest that the ERAS program can be successfully implemented in advanced ovarian cancer patients even in low-resource settings provided the program is modified to meet local needs so as not to increase healthcare costs.


Assuntos
Carcinoma Epitelial do Ovário/cirurgia , Procedimentos Cirúrgicos de Citorredução/métodos , Neoplasias Ovarianas/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Analgésicos/administração & dosagem , Antieméticos/administração & dosagem , Procedimentos Cirúrgicos de Citorredução/normas , Feminino , Hidratação , Humanos , Pessoa de Meia-Idade , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/prevenção & controle , Estudos Prospectivos , Resultado do Tratamento , Adulto Jovem
17.
Biophys J ; 112(8): 1571-1585, 2017 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-28445749

RESUMO

Earliest events in the aggregation process, such as single molecule reconfiguration, are extremely important and the most difficult to characterize in experiments. To this end, we have used well-tempered bias exchange metadynamics simulations to determine the equilibrium ensembles of an insulin molecule under amyloidogenic conditions of low pH and high temperature. A bin-based clustering method that uses statistics accumulated in bias exchange metadynamics trajectories was employed to construct a detailed thermodynamic and kinetic model of insulin folding. The highest lifetime, lowest free-energy ensemble identified consisted of native conformations adopted by a folded insulin monomer in solution, namely, the R-, the Rf-, and the T-states of insulin. The lowest free-energy structure had a root mean square deviation of only 0.15 nm from native x-ray structure. The second longest-lived metastable state was an unfolded, compact monomer with little similarity to the native structure. We have identified three additional long-lived, metastable states from the bin-based model. We then carried out an exhaustive structural characterization of metastable states on the basis of tertiary contact maps and per-residue accessible surface areas. We have also determined the lowest free-energy path between two longest-lived metastable states and confirm earlier findings of non-two-state folding for insulin through a folding intermediate. The ensemble containing the monomeric intermediate retained 58% of native hydrophobic contacts, however, accompanied by a complete loss of native secondary structure. We have discussed the relative importance of nativelike versus nonnative tertiary contacts for the folding transition. We also provide a simple measure to determine the importance of an individual residue for folding transition. Finally, we have compared and contrasted this intermediate with experimental data obtained in spectroscopic, crystallographic, and calorimetric measurements during early stages of insulin aggregation. We have also determined stability of monomeric insulin by incubation at a very low concentration to isolate protein-protein interaction effects.


Assuntos
Insulina/química , Animais , Análise por Conglomerados , Cristalografia por Raios X , Ligação de Hidrogênio , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Insulina/metabolismo , Cinética , Modelos Químicos , Simulação de Dinâmica Molecular , Ressonância Magnética Nuclear Biomolecular , Análise de Componente Principal , Agregados Proteicos , Dobramento de Proteína , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Suínos , Termodinâmica
19.
Org Biomol Chem ; 15(7): 1661-1669, 2017 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-28128389

RESUMO

In this paper, we presented a new design strategy for a peptide-based chiral supramolecular assembly. A series of aryl linked peptides 1a-1f were designed and synthesized. The bis-urea peptides 1a-1c self-assembled into a helical supramolecular arrangement resembling Trp zipper (Trpzip) structures present in proteins. Interestingly, a dihydrogenphosphate anion, upon binding to the assembly, could invert the chirality of the supramolecular assembly which could be reverted to the original by the addition of water. This chiroptical behavior can be repeated several times. Microscopy analysis showed that the supramolecular helices were assembled to form spheres. In addition to that, we also found that the handedness of supramolecular chirality is dependent on the position of Trp residues on the aromatic scaffold. Both left and right handed helical supramolecular arrangements were obtained by placing l-Trp residues at different positions on the aromatic core. The unprecedented Trpzip in these designed small peptidomimetics will stimulate more work in the area of peptide-based assemblies.


Assuntos
Peptídeos/síntese química , Triptofano/síntese química , Conformação Molecular , Simulação de Dinâmica Molecular , Tamanho da Partícula , Peptídeos/química , Propriedades de Superfície , Triptofano/química
20.
J Trop Pediatr ; 62(1): 10-8, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26428196

RESUMO

INTRODUCTION: Healthcare-associated conjunctivitis (HAC) can lead to serious sequelae including blindness. We conducted a one-year prospective study to determine the epidemiology of neonatal HAC at a tertiary-care hospital in India. METHODS: From the neonates fulfilling a set of predefined inclusion criteria, cases of HAC were diagnosed based on CDC guidelines. Conjunctival swabs, obtained from neonates with suggestive clinical signs, were processed using standard protocols. Twenty-eight potential risk factors were analyzed. RESULTS: We detected 24 cases of HAC among 591 enrolled neonates, with Escherichia coli being the most frequently isolated microorganism. On multivariate analysis, intubation at birth (p = 0.046) and orogastric feeding (p = 0.029) had a statistically significant association with neonatal HAC. Average hospitalization increased from 9.6 to 20.8 days for neonates diagnosed with HAC. CONCLUSION: A standardized case-definition and physician awareness of potential serious sequelae would help improve detection rates and timely institution of therapy. Hand hygiene could help control the menace of neonatal HAC.


Assuntos
Conjuntivite Bacteriana/epidemiologia , Infecção Hospitalar/epidemiologia , Surtos de Doenças/estatística & dados numéricos , Unidades de Terapia Intensiva Neonatal/estatística & dados numéricos , Criança , Conjuntivite Bacteriana/diagnóstico , Conjuntivite Bacteriana/etiologia , Feminino , Bactérias Gram-Negativas/isolamento & purificação , Bactérias Gram-Positivas/isolamento & purificação , Humanos , Incidência , Índia/epidemiologia , Recém-Nascido , Masculino , Estudos Prospectivos , Fatores de Risco , Atenção Terciária à Saúde
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