RESUMEN
AIMS: Since management of catheter-associated infections, which are generally biofilm-based, is attempted in certain patients such as older and frail patients by using a catheter lock solution (CLS), we examined the combination of N-acetyl cysteine (NAC), an antibiofilm agent, and levofloxacin, a broad-spectrum antimicrobial agent, for this purpose. METHODS AND RESULTS: Intravascular catheters were colonized with methicillin-resistant Staphylococcus epidermidis, levofloxacin-sensitive/methicillin-resistant Staph. aureus, levofloxacin-resistant/methicillin-resistant Staph. aureus, vancomycin-resistant Enterococcus, Escherichia coli, Klebsiella pneumoniae or Pseudomonas aeruginosa and treated with a CLS containing normal saline, NAC, levofloxacin or NAC plus levofloxacin (NACLEV) and then cultured to assess their antimicrobial activities. We also examined antibiofilm and antimicrobial activities of each CLS by scanning electron microscopy (SEM) and the mechanical integrity of catheters exposed to CLS. Treatment of colonized catheters with NACLEV-CLS significantly reduced colonization (p < 0.005) against all pathogens. SEM images also indicate reduction in colonization with NACLEV-CLS with considerable reduction in both visible bacteria and the associated biofilm. Mean tensile strength of catheters exposed to CLS was not significantly different compared to controls (p > 0.05). CONCLUSIONS: These in vitro results suggest that NACLEV-CLS can significantly reduce all bacterial colonization and potentially help salvage infected catheters without affecting the catheter's mechanical integrity. SIGNIFICANCE AND IMPACT OF STUDY: This study presents a novel CLS with a broad spectrum of antimicrobial activity against catheter-associated infections, particularly in long-term catheters.
Asunto(s)
Antiinfecciosos , Infecciones Relacionadas con Catéteres , Staphylococcus aureus Resistente a Meticilina , Acetilcisteína/farmacología , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Biopelículas , Infecciones Relacionadas con Catéteres/tratamiento farmacológico , Infecciones Relacionadas con Catéteres/microbiología , Infecciones Relacionadas con Catéteres/prevención & control , Catéteres/microbiología , Escherichia coli , Humanos , Levofloxacino/farmacología , Staphylococcus aureusRESUMEN
OBJECTIVE: Ketosis-prone diabetes (KPD) is an emerging syndrome that encompasses several distinct phenotypic subgroups that share a predisposition to diabetic ketoacidosis. We investigated whether the A-beta- subgroup of KPD, characterized by complete insulin dependence, absent beta-cell functional reserve, lack of islet cell autoantibodies, and strong family history of type 2 diabetes, represents a monogenic form of diabetes. RESEARCH DESIGN AND METHODS: Over 8 years, 37 patients with an A-beta- phenotype were identified in our longitudinally followed cohort of KPD patients. Seven genes, including hepatocyte nuclear factor 4A (HNF4A), glucokinase (GCK), HNF1A, pancreas duodenal homeobox 1 (PDX1), HNF1B, neurogenic differentiation 1 (NEUROD1), and PAX4, were directly sequenced in all patients. Selected gene regions were also sequenced in healthy, unrelated ethnically matched control subjects, consisting of 84 African American, 96 Caucasian, and 95 Hispanic subjects. RESULTS: The majority (70%) of the A-beta- KPD patients had no significant causal polymorphisms in either the proximal promoter or coding regions of the seven genes. The combination of six potentially significant low-frequency, heterozygous sequence variants in HNF-1 alpha (A174V or G574S), PDX1 (putative 5'-untranslated region CCAAT box, P33T, or P239Q), or PAX4 (R133W) were found in 27% (10/37) of patients, with one additional patient revealing two variants, PDX1 P33T and PAX4 R133W. The A174V variant has not been previously reported. CONCLUSIONS: Despite its well-circumscribed, robust, and distinctive phenotype of severe, nonautoimmune-mediated beta-cell dysfunction, A-beta- KPD is most likely not a predominantly monogenic diabetic syndrome. Several A-beta- KPD patients have low-frequency variants in HNF1A, PDX1, or PAX4 genes, which may be of functional significance in their pathophysiology.
Asunto(s)
Diabetes Mellitus Tipo 1/genética , Adulto , Autoanticuerpos/sangre , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Diabetes Mellitus Tipo 1/clasificación , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Diabetes Mellitus Tipo 2/genética , Femenino , Variación Genética , Glucoquinasa/genética , Hemoglobina Glucada/metabolismo , Factor Nuclear 1-beta del Hepatocito/genética , Factor Nuclear 4 del Hepatocito/genética , Proteínas de Homeodominio/genética , Humanos , Insulina/uso terapéutico , Células Secretoras de Insulina/fisiología , Islotes Pancreáticos/inmunología , Masculino , Persona de Mediana Edad , Factores de Transcripción Paired Box/genética , Transactivadores/genéticaRESUMEN
The Human Genome Project has facilitated the sequencing of many species, yet the current Sanger method is too expensive, labor intensive and time consuming to accomplish medical resequencing of human genomes en masse. Of the 'next-generation' technologies, cyclic reversible termination (CRT) is a promising method with the goal of producing accurate sequence information at a fraction of the cost and effort. The foundation of this approach is the reversible terminator (RT), its chemical and biological properties of which directly impact the performance of the sequencing technology. Here, we have discovered a novel paradigm in RT chemistry, the attachment of a photocleavable, 2-nitrobenzyl group to the N(6)-position of 2'-deoxyadenosine triphosphate (dATP), which, upon incorporation, terminates DNA synthesis. The 3'-OH group of the N(6)-(2-nitrobenzyl)-dATP remains unblocked, providing favorable incorporation and termination properties for several commercially available DNA polymerases while maintaining good discrimination against mismatch incorporations. Upon removal of the 2-nitrobenzyl group with UV light, the natural nucleotide is restored without molecular scarring. A five-base experiment, illustrating the exquisite, stepwise addition through a homopolymer repeat, demonstrates the applicability of the N(6)-(2-nitrobenzyl)-dATP as an ideal RT for CRT sequencing.
Asunto(s)
ADN Polimerasa Dirigida por ADN/metabolismo , ADN/biosíntesis , Nucleótidos de Desoxiadenina/química , Análisis de Secuencia de ADN/métodos , Alquilación , Disparidad de Par Base , Nucleótidos de Desoxiadenina/síntesis química , Nucleótidos de Desoxiadenina/efectos de la radiación , Desoxiadenosinas/síntesis química , Desoxiadenosinas/química , Fotoquímica , Rayos UltravioletaRESUMEN
Contiguous gene syndromes (CGS) are a group of disorders associated with chromosomal rearrangements of which the phenotype is thought to result from altered copy numbers of physically linked dosage-sensitive genes. Smith-Magenis syndrome (SMS) is a CGS associated with a deletion within band p11.2 of chromosome 17. Recently, patients harboring the predicted reciprocal duplication product [dup(17)(p11.2p11.2)] have been described as having a relatively mild phenotype. By chromosomal engineering, we created rearranged chromosomes carrying the deletion [Df(11)17] or duplication [Dp(11)17] of the syntenic region on mouse chromosome 11 that spans the genomic interval commonly deleted in SMS patients. Df(11)17/+ mice exhibit craniofacial abnormalities, seizures, marked obesity, and male-specific reduced fertility. Dp(11)17/+ animals are underweight and do not have seizures, craniofacial abnormalities, or reduced fertility. Examination of Df(11)17/Dp(11)17 animals suggests that most of the observed phenotypes result from gene dosage effects. Our murine models represent a powerful tool to analyze the consequences of gene dosage imbalance in this genomic interval and to investigate the molecular genetic bases of both SMS and dup(17)(p11.2p11.2).