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1.
Am Surg ; 90(6): 1434-1438, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38520273

RESUMO

BACKGROUND: The aim of this study is to compare impact of COVID-19 on trauma volume and characteristics on a set of trauma centers with a rural catchment area. The COVID-19 pandemic has affected different parts of the country quite differently, both in case volume and in local responses. State-wide responses have varied considerably, including variations in local mask mandates, school closures, and social distancing measures. METHODS: This was a retrospective trauma registry review of patients who were admitted to three of the tertiary care trauma centers in North and South Dakota between 2014 through 2022. RESULTS: In the analysis of 36,397 patients, we found a significant increase in trauma patient volume during the COVID-19 pandemic, with an increased percentage of patients presenting with a mechanism of injury secondary to abuse or assault. This increase in patient volume continued to rise during 2021 and 2022. CONCLUSIONS: Our study demonstrates how the COVID-19 pandemic impacted trauma center admissions in the rural and frontier Midwest differently from more urban areas, and the importance of including a variety of settings in trauma research.


Assuntos
COVID-19 , Centros de Traumatologia , Ferimentos e Lesões , Humanos , COVID-19/epidemiologia , COVID-19/prevenção & controle , Estudos Retrospectivos , Ferimentos e Lesões/epidemiologia , Centros de Traumatologia/estatística & dados numéricos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , South Dakota/epidemiologia , Sistema de Registros , North Dakota/epidemiologia , Adolescente , Pandemias , Adulto Jovem , Idoso , População Rural/estatística & dados numéricos
2.
Immunohematology ; 38(1): 13-16, 2022 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-35852059

RESUMO

A woman with autoimmune hemolytic anemia (AIHA) presented in the emergency department with life-threatening anemia (hemoglobin 3 g/dL). Exaggeration of preexisting chronic anemia to severe anemia after a recent red blood cell (RBC) transfusion led to suspicion of delayed hemolytic transfusion reaction. Given the urgency for transfusion along with a stronger suspicion for coexistence of an alloantibody, the dilution method proposed by Lawrence Petz and George Garratty was used to find an RBC unit for transfusion. An alloantibody with Fyb specificity was identified, which was masked by the coexistent autoantibody. This method is based on the assumption that the titers of an alloantibody are higher than that of autoantibody. Diluting the autoantibody would reveal the alloantibody and, for this purpose, a serial doubling dilution of serum is performed. This method has an important limitation of missing any alloantibodies with titers less than that of the autoantibody. In spite of this, this method may be of use at a resource-poor setting, where trained personnel and other reagents intended for advanced immunohematology methods are unavailable.


Assuntos
Anemia Hemolítica Autoimune , Anemia Hemolítica Autoimune/diagnóstico , Anemia Hemolítica Autoimune/terapia , Autoanticorpos , Transfusão de Sangue , Transfusão de Eritrócitos/métodos , Feminino , Humanos , Isoanticorpos
3.
Transfus Clin Biol ; 29(3): 269-272, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35288280

RESUMO

A delayed haemolytic transfusion reaction (DHTR) encompasses a positive direct antiglobulin test (DAT) developed anytime between 24 hours to 28days after cessation of transfusion, a positive eluate or a newly identified alloantibody in the plasma or serum along with features of haemolysis in the patient. Routinely, it is expected that with the transfusion of one unit of packed red cells in a patient of average height and weight, the haemoglobin level and hematocrit increase by 1 g/dL and 3% respectively. However, in a patient with DHTR, an inadequate rise of post-transfusion haemoglobin (<1 g/dL) or rapid fall in haemoglobin back to pre-transfusion levels is observed. Kidd antibodies are particularly known to cause DHTR, maybe alone or in unison with other antibodies. Detection of these alloantibodies is consequential in providing good transfusion support to these patients. These events may be difficult to detect as they may present as varied clinical features or immunological nuisances. In this case series, we have presented three cases of DHTR with special emphasis on their clinical presentations, immunohaematological evaluations, laboratory parameters and the role of proper transfusion support in these patients to avoid further complications.


Assuntos
Reação Transfusional , Hemoglobinas , Hemólise , Humanos , Isoanticorpos , Reação Transfusional/etiologia
4.
Clin Transl Sci ; 14(4): 1272-1279, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33278330

RESUMO

Neuropathic pain affects ~ 6.9-10% of the general population and leads to loss of function, anxiety, depression, sleep disturbance, and impaired cognition. Here, we report the safety, tolerability, and pharmacokinetics of a voltage-dependent and use-dependent sodium channel blocker, vixotrigine, currently under investigation for the treatment of neuropathic pain conditions. The randomized, placebo-controlled, phase I clinical trials were split into single ascending dose (SAD) and multiple ascending dose (MAD) studies. Healthy volunteers received oral vixotrigine as either single doses followed by a ≥ 7-day washout period for up to 5 dosing sessions (SAD, n = 30), or repeat doses (once or twice daily) for 14 and 28 days (MAD, n = 51). Adverse events (AEs), maximum observed vixotrigine plasma concentration (Cmax ), area under the concentration-time curve from predose to 24 hours postdose (AUC0-24 ), time to Cmax (Tmax ), and terminal half-life (t1/2), among others, were assessed. Drug-related AEs were reported in 47% and 53% of volunteers in the SAD and MAD studies, respectively, with dizziness as the most commonly reported drug-related AE. SAD results showed that Cmax and AUC increased with dose, Tmax was 1-2 hours, and t1/2 was ~ 11 hours. A twofold increase in accumulation was observed when vixotrigine was taken twice vs. once daily (MAD). Steady-state was achieved from day 5 onward. These data indicate that oral vixotrigine is well-tolerated when administered as single doses up to 825 mg and multiple doses up to 450 mg twice daily.


Assuntos
Tontura/epidemiologia , Éteres Fenílicos/efeitos adversos , Prolina/análogos & derivados , Bloqueadores dos Canais de Sódio/efeitos adversos , Administração Oral , Adolescente , Adulto , Idoso , Área Sob a Curva , Tontura/induzido quimicamente , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Meia-Vida , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Neuralgia/tratamento farmacológico , Éteres Fenílicos/administração & dosagem , Éteres Fenílicos/farmacocinética , Prolina/administração & dosagem , Prolina/efeitos adversos , Prolina/farmacocinética , Bloqueadores dos Canais de Sódio/administração & dosagem , Bloqueadores dos Canais de Sódio/farmacocinética , Adulto Jovem
5.
Cureus ; 12(8): e9898, 2020 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-32968564

RESUMO

BACKGROUND:  Head and neck (H&N) cancers account for 4% of total cancers diagnosed. However, quality of life (QoL) implications are more severe for this patient population due to the complexity, extent, and deformities resulting from treatment interventions. Principally debilitating complications include diminished functional walking capacity, reduced cervical range of motion (ROM), and scapular strength. An extensive literature search revealed a paucity of evidence utilizing physical therapy assessment and intervention for this population. The purpose of this study was to describe the development and clinical feasibility of a prehabilitation program aimed to thwart these complications for patients diagnosed with H&N cancer.  Methods: Inclusion criteria: male or female, 18+ years, speak and read the English language, ambulate independently, diagnosed with H&N cancer, and scheduled for surgical intervention. Institutional Review Board approval was obtained. Pre- and post-surgical measurements included the six-minute walk test (6MWT), cervical ROM, manual muscle testing for scapular strength, and three questionnaires: physical activity history, health behaviors questionnaire, and the Functional Assessment Cancer Therapy H&N QoL survey.  Results: Three participants were enrolled (two males and one female) all identifying as Caucasian and between 60-90 years of age. Pre- to post-cervical ROM demonstrated decline in extension/bilateral rotation for two of three participants. Two participants demonstrated decreased 6MWT distance while one increased. No participants experienced any adverse effects of the prehabilitation program.  Conclusion: This is the first study protocol to describe a physical therapist-administered H&N cancer prehabilitation program. Professionally administered education and exercise has potential to prevent, manage, and mitigate the adverse effects of cancer treatment. Additional research is needed to define the importance of prehabilitation relative to improved clinical outcomes and improved QoL. Patients with a cancer diagnosis are susceptible to impairments and functional limitations as a result of treatments and this prehabilitation program demonstrates potential to positively impact outcomes across the survivorship continuum. Due to their education and integration within the medical system, physical therapists are well-positioned to lead the effort to unify theory and clearly define parameters for oncology prehabilitation.

6.
Cureus ; 11(8): e5382, 2019 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-31616613

RESUMO

BACKGROUND: Oxidative stress (OS) can bring about an imbalance between the production of free radicals (pro-oxidants) and their elimination by protective mechanisms (antioxidants). Exercise and/or physical activity (PA) may provide a mechanism to control the variation and equilibrium between pro-oxidants and antioxidants. PURPOSE:  The purpose of this narrative review is to investigate the evidence regarding the effect of exercise and/or PA on OS among individuals diagnosed with cancer.  Methods: A narrative review study design involved a literature search (August 2016) across the databases: Cumulative Index of Nursing and Allied Health Literature (CINAHL), Cochrane, Excerpta Medica database (Embase), and PubMed. Articles included those published from January 2000 - August 2016; inclusive of the search terms "cancer" AND "neoplasm" AND "oncology" AND "oxidative stress" AND "exercise" AND "physical activity"; written in the English language; and utilizing human subjects. The references of the selected articles were then reviewed to identify any qualifying articles. A modified Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) review of each article was completed by two investigators. RESULTS:  Eight articles met the final inclusion criteria. Moderate exercise may provide protective mechanisms against OS via increased antioxidant activity, while exhaustive exercise may be responsible for increased levels of OS, increasing the risk for malignancy. While increased OS levels are utilized by current oncologic therapies to damage malignant and premalignant cells, they also damage healthy cells (cardiac, nerve, and lymphatic). CONCLUSION: Moderate levels of exercise and/or PA may provide preventative and protective qualities against the negative side effects associated with increased OS from cancer treatment.

7.
Cureus ; 10(3): e2272, 2018 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-29736356

RESUMO

PURPOSE: To conduct a descriptive analysis of the results from the Functional Assessment of Cancer Therapy-General (FACT-G) quality of life (QOL) questionnaire, describe the outcomes from the FACT-G to drive treatment recommendations within the breast survivorship clinic and to quantify the severity of QOL issues experienced. METHODS: A retrospective analysis utilizing medical records of participants in a breast cancer survivorship clinic. Measurement data included demographics and FACT-G results. Descriptive analysis of demographics and trends in referral recommendations and FACT-G scores was completed. RESULTS: All 30 participants were females diagnosed with breast cancer of various stages, ages 28 to 81 years. Approximately 1.5 years elapsed between cancer diagnosis and completion of the FACT-G. Participants received surgery (100%), radiation (76%), and chemotherapy and/or hormonal therapy (43%). Results demonstrated that participants reported having a lack of energy (24%) and were bothered by side effects of their treatment (20%). The greatest impact on functional well-being was difficulty sleeping (50%). LIMITATIONS: Decreased ability to generalize the data to breast cancer survivors due to small sample size from one institution and potential referral bias. CONCLUSIONS: Cancer survivors experience QOL issues throughout the continuum of their care, which can result in long-term effects on their physical, functional, social and emotional well-being. QOL is a major focus for cancer survivors and many times determines a survivor's healthcare decisions. QOL measurements can be utilized at multiple points during survivorship to identify the need for referrals and to guide interventions.

8.
FEBS Lett ; 588(10): 1967-72, 2014 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-24735726

RESUMO

Antisense RNA ribozymes have intrinsic endonucleolytic activity to effect cleavage of the target RNA. However, this activity in vivo is often controlled by the dominance of antisense or other double-stranded RNA mechanism. In this work, we demonstrate the in planta activity of a hammerhead ribozyme designed to target rep-mRNA of a phytopathogen Mungbean Yellow Mosaic India virus (MYMIV) as an antiviral agent. We also found RNA-silencing is induced on introduction of catalytically active as well as inactive ribozymes. Using RNA-silencing suppressors (RSS), we demonstrate that the endonucleolytic activity of ribozymes is a true phenomenon, even while a mutated version may demonstrate a similar down-regulation of the target RNA. This helps to ease the confusion over the action mechanism of ribozymes in vivo.


Assuntos
Interferência de RNA , RNA Catalítico/genética , RNA Mensageiro/genética , Proteínas Virais/genética , Begomovirus/genética , Northern Blotting , Endonucleases/genética , Endonucleases/metabolismo , Fabaceae/virologia , Doenças das Plantas/genética , Doenças das Plantas/virologia , Folhas de Planta/genética , Folhas de Planta/virologia , RNA Catalítico/metabolismo , RNA Mensageiro/metabolismo , RNA de Plantas/genética , RNA de Plantas/metabolismo , RNA Viral/genética , RNA Viral/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Nicotiana/genética , Nicotiana/virologia
9.
Indian J Chest Dis Allied Sci ; 56(3): 175-7, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25823114

RESUMO

A 33-year-old male presented with repeated episodes of blood-streaked sputum for last one-and half-year. Chest radiograph showed consolidation in the right lower zone. Fibreoptic bronchoscopy revealed an endoluminal growth in the right lower lobe bronchus. Histopathological examination of bronchoscopic biopsy specimen confirmed adenoid cystic carcinoma.


Assuntos
Carcinoma Adenoide Cístico/diagnóstico , Neoplasias Pulmonares/diagnóstico , Adulto , Broncoscopia , Carcinoma Adenoide Cístico/diagnóstico por imagem , Carcinoma Adenoide Cístico/patologia , Humanos , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/patologia , Masculino , Radiografia
10.
J Helminthol ; 85(2): 196-203, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20735897

RESUMO

Cystic echinococcosis (CE) caused by the larval stage of Echinococcus granulosus is a disease that affects both humans and animals. In humans the disease is treated by surgery with a supplementary option of chemotherapy with a benzimidazole compound. During the present study heat-shock protein 60 (HSP 60) was identified as one of the most frequently expressed biomolecules by E. granulosus after albendazole treatment. Data were correlated with 14-3-3 protein signature, and overexpression of this molecule after albendazole induction was an indicator of cell survival and signal transduction during in vitro maintenance of E. granulosus for up to 72 h. This observation was further correlated with a uniform expression pattern of a housekeeping gene (actin II). Out of three ß-tubulin gene isoforms of E. granulosus, ß-tubulin gene isoform 2 showed a conserved point mutation indicative of benzimidazole resistance.


Assuntos
Proteínas 14-3-3/genética , Anti-Helmínticos/farmacologia , Chaperonina 60/genética , Resistência a Medicamentos , Echinococcus granulosus/efeitos dos fármacos , Echinococcus granulosus/genética , Proteínas 14-3-3/biossíntese , Sequência de Aminoácidos , Animais , Chaperonina 60/biossíntese , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Dados de Sequência Molecular , Proteínas Mutantes/genética , Mutação Puntual , Tubulina (Proteína)/genética
11.
Plasmid ; 65(2): 110-7, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21087624

RESUMO

Corynebacterium renale harbors four small cryptic plasmids, pCR1, pCR2, pCR3 and pCR4, and can be a good system for understanding host-plasmid interactions. In the present study, effect of plasmid loss and their subsequent introduction on various properties of the host was evaluated. Loss of plasmids caused a reduction in bacterial size and also slowed down their growth rate, µ, and respiratory rate, r. Both µ and r values were partially recovered in C. renale R, obtained by retransformation of the cured strain with all the four cryptic plasmids. Further delineation revealed that a 3153bp plasmid pCR2 alone is sufficient for the observed increase in µ in C. renale R. The advantages conferred by the remaining three plasmids may be are two subtle to be seen under laboratory conditions. Overall, the observations point to the gross metabolic crisis in the host partly as a result of loss of plasmids. Based on the findings, a mutualistic relationship between the host and the plasmids resulting from their coevolution is proposed.


Assuntos
Corynebacterium/genética , Corynebacterium/metabolismo , Plasmídeos/genética , Plasmídeos/metabolismo , Corynebacterium/citologia , Corynebacterium/ultraestrutura , Glucose/metabolismo , Mapeamento por Restrição
12.
Singapore Med J ; 50(12): e415-8, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20087544

RESUMO

A 22-year-old male patient was admitted with severe cough associated with purulent expectoration, left-sided chest pain and breathlessness. There was a history of recurrent respiratory ailments since childhood. The patient appeared younger than his chronological age. His face and ears were both dysmorphic. Clinically, the patient was diagnosed with Ehlers-Danlos syndrome (EDS). Computed tomography of the thoracic region revealed hypoplasia of the left lung and hyperplasia of the right lung. Both the patellae were absent. However, ultrasonography of his abdomen, echocardiography and other routine blood and urine examination showed no gross abnormalities. Although other respiratory tract abnormalities with EDS are not uncommon, unilateral lung hypoplasia and patellar agenesis in EDS make this case unique.


Assuntos
Síndrome de Ehlers-Danlos/patologia , Pulmão/anormalidades , Pulmão/patologia , Patela/anormalidades , Síndrome de Ehlers-Danlos/diagnóstico por imagem , Humanos , Pulmão/diagnóstico por imagem , Masculino , Tomografia Computadorizada por Raios X , Adulto Jovem
13.
Biotechnol Lett ; 29(10): 1465-8, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17581702

RESUMO

Dibenzothiophene monooxygenase is the first enzyme involved in the degradation of dibenzothiophene. This gene was expressed via the pET28a vector in E. coli and was purified in a single step using affinity chromatography. The protein was purified 39-fold with a specific activity of 38 U/mg.


Assuntos
Escherichia coli/genética , Oxirredutases/isolamento & purificação , Proteínas Recombinantes/isolamento & purificação , Sequência de Aminoácidos , Sequência de Bases , Cromatografia de Afinidade , Eletroforese em Gel de Poliacrilamida , Vetores Genéticos/genética , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Oxirredutases/genética , Oxirredutases/metabolismo , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência , Temperatura , Tiofenos/metabolismo
14.
FEBS Lett ; 581(14): 2675-83, 2007 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-17531225

RESUMO

Geminiviruses pose serious threat to many economically important crops such as mungbean, tomato, cotton, etc. To devise a specific antiviral strategy at the viral DNA replication level, a hammerhead ribozyme was directed against the mRNA of the replication initiator protein (Rep). Rep is the most important viral protein for the DNA replication of the Mungbean yellow mosaic India virus (MYMIV), a member of the Geminiviridae family. The ribozyme showed approximately 33% cleavage activity on synthetic rep transcript within 1h under in vitro conditions, whereas the mutant ribozyme, designed to lack the catalytic activity but target the same site, showed no cleavage. The in vivo efficiency of ribozyme was evaluated in Saccharomyces cerevisiae as it can act as a surrogate host for replication of the MYMIV-DNA and lacks RNAi machinery. In the presence of the ribozyme, growth of the yeast cells that are dependent on geminiviral replication was inhibited by 30% and cellular generation time was increased by 2h. The RT-PCR analysis showed a maximum of about 50% reduction in the rep mRNA level in presence of the ribozyme compared to its noncatalytic mutant control. About 65% decrease in geminiviral DNA replication was observed due to the downregulation of replication initiator protein by the ribozyme. These results raise the possibility of engineering resistance to geminiviruses employing the ribozyme approach.


Assuntos
DNA Helicases/metabolismo , Proteínas de Ligação a DNA/metabolismo , Geminiviridae/genética , RNA Catalítico/metabolismo , Saccharomyces cerevisiae/virologia , Transativadores/metabolismo , Replicação Viral/genética , Sequência de Bases , DNA Helicases/genética , Proteínas de Ligação a DNA/genética , Regulação para Baixo , Geminiviridae/crescimento & desenvolvimento , Vetores Genéticos/genética , Hidrólise , Cinética , Mutação , RNA Catalítico/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Transativadores/genética
15.
Microb Cell Fact ; 6: 14, 2007 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-17490494

RESUMO

BACKGROUND: Recent developments in metabolic engineering and the need for expanded compatibility required for co-expression studies, underscore the importance of developing new plasmid vectors with properties such as stability and compatibility. RESULTS: We utilized the pCR2 replicon of Corynebacterium renale, which harbours multiple plasmids, for constructing a range of expression vectors. Different antibiotic-resistance markers were introduced and the vectors were found to be 100% stable over a large number of generations in the absence of selection pressure. Compatibility of this plasmid was studied with different Escherichia coli plasmid replicons viz. pMB1 and p15A. It was observed that pCR2 was able to coexist with these E. coli plasmids for 60 generations in the absence of selection pressure. Soluble intracellular production was checked by expressing GFP under the lac promoter in an expression plasmid pCR2GFP. Also high level production of human IFNgamma was obtained by cloning the h-IFNgamma under a T7 promoter in the expression plasmid pCR2-IFNgamma and using a dual plasmid heat shock system for expression. Repeated sub-culturing in the absence of selection pressure for six days did not lead to any fall in the production levels post induction, for both GFP and h-IFNgamma, demonstrating that pCR2 is a useful plasmid in terms of stability and compatibility. CONCLUSION: We have constructed a series of expression vectors based on the pCR2 replicon and demonstrated its high stability and sustained expression capacity, in the absence of selection pressure which will make it an efficient tool for metabolic engineering and co-expression studies, as well as for scale up of expression.

16.
Biochemistry (Mosc) ; 71(11): 1230-7, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17140384

RESUMO

Equilibrium denaturation of streptomycin adenylyltransferase (SMATase) has been studied by CD spectroscopy, fluorescence emission spectroscopy, and binding of the hydrophobic dye 1-anilino-8-naphthalene sulfonic acid (ANS). Far-UV CD spectra show retention of 90% native-like secondary structure at 0.5 M guanidine hydrochloride (GdnHCl). The mean residue ellipticities at 222 nm and enzyme activity plotted against GdnHCl concentration showed loss of about 50 and 75% of secondary structure and 35 and 60% of activity at 0.75 and 1.5 M GdnHCl, respectively. At 6 M GdnHCl, there was loss of secondary structure and activity leading to the formation of GdnHCl-induced unfolded state as evidenced by CD and fluorescence spectroscopy as well as by measuring enzymatic activity. The denaturant-mediated decrease in fluorescence intensity and 5 nm red shift of lambda(max) point to gradual unfolding of SMATase when GdnHCl is added up from 0.5 M to a maximum of 6 M. Decreasing of ANS binding and red shift (approximately 5 nm) were observed in this state compared to the native folded state, indicating the partial destruction of surface hydrophobic patches of the protein molecule on denaturation. Disruption of disulfide bonds in the protein resulted in sharp decrease in surface hydrophobicity of the protein, indicating that the surface hydrophobic patches are held by disulfide bonds even in the GdnHCl denatured state. Acrylamide and potassium iodide quenching of the intrinsic tryptophan fluorescence of SMATase showed that the native protein is in folded conformation with majority of the tryptophan residues exposed to the solvent, and about 20% of them are in negatively charged environment.


Assuntos
Dicroísmo Circular , Guanidina/farmacologia , Nucleotidiltransferases/química , Nucleotidiltransferases/metabolismo , Espectrometria de Fluorescência , Acrilamida/farmacologia , Naftalenossulfonato de Anilina/metabolismo , Mycobacterium tuberculosis/enzimologia , Iodeto de Potássio/farmacologia , Ligação Proteica , Conformação Proteica/efeitos dos fármacos , Estrutura Secundária de Proteína , Triptofano/química
17.
Plasmid ; 56(1): 24-34, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16545871

RESUMO

Plasmid pCR1 is a cryptic plasmid harboured by Corynebacterium renale. It is the smallest corynebacterial plasmid known to date. Although its natural host is animal corynebacteria, it can replicate in several strains of soil corynebacteria. It can also replicate in Escherichia coli, in which it is stably maintained. The copy number of pCR1 in this host is higher than that of pUC19, with which it shows unidirectional incompatibility. It is also incompatible with pBK2, a plasmid bearing the common corynebacterial replicon pBL1. Its size is 1488bp, as revealed by DNA sequencing. A total of eight open reading frames (ORF) were detected in this plasmid, the largest of which codes for a putative Rep protein of predicted molecular mass of 21kDa. The plasmid pCR1 can be mobilized by the plasmid R6K from E. coli to other corynebacteria. Sequence analysis revealed the presence of an oriT homologous to that of R64. An E. coli plasmid pKL1 shows more than 90% identity with pCR1. Like many coryenbacterial plasmids, pCR1 also replicates by rolling circle mode.


Assuntos
Corynebacterium/genética , Plasmídeos/metabolismo , Sequência de Aminoácidos , Sequência de Bases , Escherichia coli/metabolismo , Vetores Genéticos , Microscopia Eletrônica de Transmissão , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Plasmídeos/química , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Homologia de Sequência do Ácido Nucleico
18.
Appl Microbiol Biotechnol ; 70(2): 140-50, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16391922

RESUMO

Aminoglycosides are potent bactericidal antibiotics targeting the bacterial ribosome, where they bind to the A-site and disrupt protein synthesis. They are particularly active against aerobic, Gram-negative bacteria and act synergistically against certain Gram-positive organisms. Aminoglycosides are used in the treatment of severe infections of the abdomen and urinary tract, bacteremia, and endocarditis. They are also used for prophylaxis, especially against endocarditis. Bacterial resistance to aminoglycosides continues to escalate and is widely recognized as a serious health threat. This might be the reason for the interest in understanding the mechanisms of resistance. It is now clear that the resistance occurs by different mechanisms such as prevention of drug entry, active extrusion of drugs, alteration of the drug target (mutational modification of 16S rRNA and mutational modification of ribosomal proteins), and enzymatic inactivation through the expression of enzymes, which covalently modify these antibiotics. Enzymatic inactivation is normally due to acetyltransferases, nucleotidyltransferases, and phosphotransferases. In this review, we focus on the recent concept of molecular understanding of aminoglycoside action and resistance.


Assuntos
Aminoglicosídeos/farmacologia , Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Aminoglicosídeos/química , Aminoglicosídeos/metabolismo , Antibacterianos/química , Antibacterianos/metabolismo , Humanos
19.
Biotechnol Lett ; 27(7): 519-24, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15928860

RESUMO

Bacterial resistance to the aminoglycoside antibiotics is manifested primarily by enzymic modification of these drugs. One important mechanism of streptomycin modification is through ATP-dependent O-adenylation, catalyzed by streptomycin adenylyltransferase. Initial velocity patterns deduced from steady state kinetics indicate a sequential mechanism. Dead-end inhibition by tobramycin and neomycin is non-competitive versus streptomycin and uncompetitive versus ATP, indicative of ordered substrate binding where ATP binds first and then streptomycin. These results surmise that streptomycin adenylyltransferase follows an ordered, sequential kinetic mechanism in which one substrate (ATP) binds prior to the antibiotic and pyrophosphate is released prior to formation of AMP-streptomycin.


Assuntos
Escherichia coli/genética , Nucleotidiltransferases/metabolismo , Trifosfato de Adenosina/metabolismo , Difosfatos/metabolismo , Inibidores Enzimáticos/farmacologia , Escherichia coli/enzimologia , Cinética , Neomicina/farmacologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Estreptomicina/metabolismo , Tobramicina/farmacologia
20.
Curr Drug Targets ; 6(3): 353-61, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15857293

RESUMO

Aminoglycosides are a class of clinically important antibiotics used in the treatment of infections caused by Gram-positive and Gram-negative organisms. They are bactericidal, targeting the bacterial ribosome, where they bind to the A-site and disrupt protein synthesis. Antibiotic resistance is a growing problem for all classes of anti-infective agents. One of the first groups of antibiotics to encounter the challenge of resistance was the aminoglycoside -aminocyclitol family. Initially, the resistance that emerged in organisms such as Mycobacterium tuberculosis was restricted to modification of the antibiotic targets, which we now know to be the bacterial ribosomal rRNA and proteins. As new aminoglycosides came to the clinic, however, the prevalence of chemical modification mechanisms of resistance became dominant. Enzymatic modification of aminoglycosides through kinases (O-phosphotransferases, APHs), O-adenyltransferases (ANTs) and N-acetyltransferases (AACs) has emerged in virtually all clinically relevant bacteria of both Gram-positive and Gram-negative origin. Although their clinical use has been extensive, their toxicity and the prevalence of resistance in clinical strains have prompted the pharmaceutical industry to look for alternatives. Whereas the search for novel targets for antibiotics from the genomic information is ongoing, no antibacterial agent based on these efforts has so far entered clinical trials. Meanwhile, structural knowledge of the ribosome, the target for aminoglycosides, has invigorated the field of antibiotic development. It is expected that knowledge of the binding interactions of aminoglycosides and the ribosome would lead to concepts in drug design that would take us away from the parental structures of aminoglycosides in the direction of different structural classes that bind to the same ribosomal target sites as aminoglycosides. The challenge to ensure the continued use of these highly potent antibacterial agents will require the effective management of resistance at several levels. One potential mechanism of circumventing resistance is the development of inhibitors of modification enzymes, a methodology that is now well established in the beta-lactam field. This approach requires knowledge of resistance at the molecular and atomic levels for the rational design of inhibitory molecules. The understanding of the molecular basis for aminoglycoside resistance modification has been greatly enhanced by the recent availability of representative 3D-structures from the three classes of modifying enzymes: kinases, acetyltransferases and adenyltransferases. The challenge is now to firmly establish the mechanisms of enzyme action and to use this information to prepare effective and potent inhibitors that will reverse antibiotic resistance. In this review, we discuss the molecular mechanisms of resistance of aminoglycosides specifically on aminoglycoside-modifying enzymes and newly developed strategies to circumvent resistance including antisense technology, which is an example of new strategy to deal with antibiotic resistance.


Assuntos
Aminoglicosídeos/farmacologia , Desenho de Fármacos , Farmacorresistência Bacteriana , Inibidores Enzimáticos/farmacologia , Canamicina Quinase/antagonistas & inibidores , Nucleotidiltransferases/antagonistas & inibidores , Aminoglicosídeos/farmacocinética , Sítios de Ligação , Oligonucleotídeos Antissenso/farmacologia
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