Design of titanium nitride- and wolfram carbide-doped RGO/GC electrodes for determination of gallic acid.

In the present paper, the electrochemical behavior and the properties of two modified glassy carbon (GC) electrodes used for quantification of gallic acid in sweet wines were compared. A comparative study was conducted between titanium nitride- or wolfram carbide-doped reduced graphene oxide, labeled as TNrGO and WCrGO, respectively, modified GC electrodes, which are promising composite nanomaterials for electroanalytical applications. For the first time, WCrGO was synthesized and its electroanalytical properties compared with those of TNrGO. Results showed that the proposed materials exhibited enhanced characteristics, e.g., low limits of detection (1.1 µM and 3.1 µM for TNrGO and WCrGO, respectively), wide linear ranges (for TNrGO 4.5-76 µM and for WCrGO 10-100 µM), low adsorption, and low background current, which make them promising candidates for electrochemical sensing applications.

An HPLC-SEC-based rapid quantification method for vesicular stomatitis virus particles to facilitate process development.

Virus particle (VP) quantification plays a pivotal role in the development of production processes of VPs for virus-based therapies. The yield based on total VP count serves as a process performance indicator for evaluating process efficiency and consistency. Here, a label-free particle quantification method for enveloped VPs was developed, with potential applications in oncolytic virotherapy, vaccine development, and gene therapy. The method comprises size-exclusion chromatography (SEC) separation using high-performance liquid chromatography (HPLC) instruments. Ultraviolet (UV) was used for particle quantification and multi-angle light scattering (MALS) for particle characterization. Consistent recoveries of over 97% in the SEC were achieved upon mobile phase screenings and addition of bovine serum albumin (BSA) as sample stabilizer. A calibration curve was generated, and the method's performance and applicability to in-process samples were characterized. The assay's repeatability variation was <1% and its intermediate precision variation was <3%. The linear range of the method spans from 7.08 × 108 to 1.72 × 1011 VP/mL, with a limit of detection (LOD) of 7.72 × 107 VP/mL and a lower limit of quantification (LLOQ) of 4.20 × 108 VP/mL. The method, characterized by its high precision, requires minimal hands-on time and provides same-day results, making it efficient for process development.

Isolation and structural characterization of a non-diketopiperazine phytotoxin from a potato pathogenic Streptomyces strain.

Two Streptomyces spp. strains responsible for potato common scab infections in Uruguay which do not produce diketopiperazines were identified through whole-genome sequencing, and the virulence factor produced by one of them was isolated and characterized. Phylogenetic analysis showed that both pathogenic strains can be identified as S. niveiscabiei, and the structure of the phytotoxin was elucidated as that of the polyketide desmethylmensacarcin using MS and NMR methods. The metabolite is produced in yields of ∼200 mg/L of culture media, induces deep necrotic lesions on potato tubers, stuns root and shoot growth in radish seedlings, and is comparatively more aggressive than thaxtomin A. This is the first time that desmethylmensacarcin, a member of a class of compounds known for their antitumor and antibiotic activity, is associated with phytotoxicity. More importantly, it represents the discovery of a new virulence factor related to potato common scab, an economically-important disease affecting potato production worldwide.

Nmnat1-Rbp7 Is a Conserved Fusion-Protein That Combines NAD+ Catalysis of Nmnat1 with Subcellular Localization of Rbp7.

Retinol binding proteins (Rbps) are known as carriers for transport and targeting of retinoids to their metabolizing enzymes. Rbps are also reported to function in regulating the homeostatic balance of retinoid metabolism, as their level of retinoid occupancy impacts the activities of retinoid metabolizing enzymes. Here we used zebrafish as a model to study rbp7a function and regulation. We find that early embryonic rbp7a expression is negatively regulated by the Nodal/FoxH1-signaling pathway and we show that Nodal/FoxH1 activity has the opposite effect on aldh1a2, which encodes the major enzyme for early embryonic retinoic acid production. The data are consistent with a Nodal-dependent coordination of the allocation of retinoid precursors to processing enzymes with the catalysis of retinoic acid formation. Further, we describe a novel nmnat1-rbp7 transcript encoding a fusion of Rbp7 and the NAD+ (Nicotinamide adenine dinucleotide) synthesizing enzyme Nmnat1. We show that nmnat1-rbp7 is conserved in fish, mouse and chicken, and that in zebrafish regulation of nmnat1-rbp7a is distinct from that of rbp7a and nmnat1. Injection experiments in zebrafish further revealed that Nmnat1-Rbp7a and Nmnat1 have similar NAD+ catalyzing activities but a different subcellular localization. HPLC measurements and protein localization analysis highlight Nmnat1-Rbp7a as the only known cytoplasmic and presumably endoplasmic reticulum (ER) specific NAD+ catalyzing enzyme. These studies, taken together with previously documented NAD+ dependent interaction of RBPs with ER-associated enzymes of retinal catalysis, implicate functions of this newly described NMNAT1-Rbp7 fusion protein in retinol oxidation.

Human cytomegalovirus: detection of congenital and perinatal infection in Argentina.

BACKGROUND: Human cytomegalovirus (CMV) is one of the most commonly found agents of congenital infections. Primary maternal infection is associated with risk of symptomatic congenital diseases, and high morbidity is frequently associated with very low birth weight. Neonates with asymptomatic infection develop various sequelae during infancy. This is the first Argentine study performed in neonates with congenital and postnatal HCMV infection. The purpose of this study was to evaluate the performance of the polymerase chain reaction (PCR) technique with different pairs of primers, to detect cytomegalovirus isolated in tissue cultures and directly in urine and dried blood spot (DBS) specimens. Results were compared with IgM detection. METHODS: The study was performed between 1999 and 2001 on routine samples in the Laboratory. A total of 61 urine and 56 serum samples were selected from 61 newborns/infants, 33 patients whose samples were analyzed during the first two to three weeks of life were considered congenital infections; the remaining 28 patients whose samples were taken later than the third week were grouped as perinatal infections, although only in 4 the perinatal transmission of infection was determined unequivocally. Cytomegalovirus diagnosis was made by isolating the virus from urine samples in human foreskin fibroblast cells. Three different primer pairs directed to IE, LA and gB genes were used for the HCMV PCR assay in viral isolates. Subsequently, PCR and nested PCR (nPCR) assays with gB primers were performed directly in urine and in 11 samples of dried blood spot (DBS) on Guthrie Card, these results were then compared with serology. RESULTS: The main clinical manifestations of the 33 patients with congenital infection were purpura, jaundice, hepatomegaly and anaemia. Three patients presented low birth weight as single symptom, 10, intracranial calcifications, and 2, kidney failure. In the 28 patients grouped as with perinatal infection, anaemia, hepatosplenomegaly and enzymatic alteration were predominant, and 4 patients were HIV positive. The primers used to amplify the gB region had a PCR positivity rate of 100%, whereas those that amplified IE and LA regions had a PCR positivity rate of 54% and 61% respectively, in CMV isolates. Amplification by PCR of urine samples (with no previous DNA extraction), using primers for the gB region, detected 34/61 positive samples. Out of the 33 samples from patients with congenital infection, 24 (73%) were positive. When nPCR was used in these samples, all were positive, whereas in the remaining 28 patients, two negative cases were found. Cytomegalovirus DNA detection in 11 samples was also carried out in DBS: 7 DBS samples were positive and 4 were negative. CONCLUSIONS: Primers directed to the gB fragment region were the best choice for the detection of CMV DNA in positive isolates. In congenital infections, direct PCR in urine was positive in a high percentage (73%) of samples; however, in patients grouped as with perinatal infection only 36% of the cases were positive. With n-PCR, total sample positivity reached 97%. PCR technique performed in DBS allowed identifying congenital infection in four patients and to be confirmed in 3. These results show the value of nPCR for the detection of all cases of CMV infection. The assay offers the advantage that it may be performed within the normal working day and provides reliable results in a much shorter time frame than that required for either traditional tissue culture or the shell-viral assay.

Dolor Lumbar Crónico, Reto Diagnóstico: Un Caso de Tuberculosis Espinal del Hospital ESE San Juan de Dios, Girón / Chronic lumbar pain diagnostic challenge: a case of spinal tuberculosis at The San Juan de Dios Hospital, Giron

El dolor lumbar crónico es uno de los motivos más frecuentes de la consulta médica y su prevalencia ha sido calculada en un 70 por ciento en los países intustrializados. Presentamos un caso clínico cuyo diagnóstico final fue tuberculosis espinal; todo un reto, dadas las condiciones de presentación clínica en que predomina el dolor lumbar acompañado de síntomas sistémicos. La tuberculosis espinal es uno de los problemas que ha aquejado a la población mundial de una manera silente durante años. Las principales dificultades clínicas son: el retraso de los médicos para realizar el diagnóstico de tuberculosis espinal (promedio 3 meses), su largo periodo de recuperación (12 meses o más) y el alto costo de dicho tratamiento. Su presentación semiológica es dolor lumbar, acompañado de síntomas inespecíficos como fiebre y pérdida de peso, además, deformidad de la columna vertebral y complicaciones neurológicas como la paraplejía, hasta en un 50 por ciento. Su diagnóstico necesita la comprobación bacteriológica y del aislamiento de la Mycobacteria. La evaluación inicia con la radiografía simple de columna vertebral, luego tomografía axial computarizada (TAC), y/o resonancia nuclear magnética (RNM), permitiéndonos así una mejor valoración del proceso patológico y su compromiso. Actualmente, el tratamiento antibiótico junto al manejo quirúrgico han contribuido dramáticamente a alterar la historia natural de esta enfermedad

Factor de crecimiento similar a la insulina: nuevos avances y perspectivas terapéuticas / Insuline-like growth factor: new advances and therapeutic perspectives

El Factor de crecimiento I similar a la insulina (IGF-1, del término en inglés Insuline Like Growth Factor) forma parte de una familia de factores de crecimiento cuyas acciones están encaminadas a la proliferación y diferenciación de múltiples tejidos en el organismo. Su efecto fisiológico se alcanza por su interacción con receptores específicos ubicados en toda la economía del cuerpo. Para mantener una adecuada concentración plasmática y vida media biológica se requiere de proteinas ligadoras del IGF-I (IGFBPs), las cuales permiten mantener una reserva plasmática de dicho factor y algunas favorecen la interacción con sus receptores específicos. El IGF-I se ha implicado como la vía final común de algunas hormonas como la hormona de crecimiento, los esteroides sexuales, glucocorticoides y las hormonas tiroideas. Su alteración se ha relacionado con múltiples enfermedades como la baja talla, el síndrome de insensibilidad a la hormona de crecimiento y la diabetes mellitus entre otros. Su amplio espectro de acciones biológicas lo hace por tanto atractivo en la terapéutica médica, sin embargo por sus múltiples efectos en diferentes tejidos y sus funciones no del todo conocidas es necesario continuar su investigación antes de poder ser usado en la terapia humana. El presente artículo busca actualizar los conceptos sobre el IGF-I y discutir sus posibles aplicaciones terapéuticas