Quality of life, craniomandibular function, and psychosocial factors related to pain and movement in patients with head and neck cancer.

PURPOSE: To describe the characteristics of and the associations between health-related quality of life, pain, craniomandibular function, and psychosocial factors related to pain and fear of movement in patients with head and neck cancer. METHODS: Seventy-eight patients diagnosed with HNC were recruited. Measurements of the maximum mouth opening range and pressure pain thresholds on the masseter muscle and the distal phalanx of the thumb were conducted, as well as a battery of self-report questionnaires were administrated, including the QoL Questionnaire (EORT QLQ-H&N35), Numeric Rating Scale (NRS), Pain Catastrophizing Scale (PCS), the Spanish translation of the Tampa Scale for Kinesiophobia for Temporomandibular Disorders (TSK-TMD), and the short version of the Craniofacial Pain and Disability Inventory (CF-PDI-11). RESULTS: The study sample (66.7% men, mean age 60.12 [11.95] years) experienced a moderate impact on their QoL levels (57.68 [18.25] EORT QLQ-H&N35) and high kinesiophobia values (20.49 [9.11] TSK-TMD). Pain was present in 41% of the patients, but only 3.8% reported severe pain. 26.4% had a restricted mouth opening range, and 34.62% showed significant catastrophism levels. There were strong positive correlations between EORT QLQ-H&N35 and CF-PDI-11 (r = 0.81), between NRS and CF-PDI-11 (r = 0.74), and between PCS and CF-PDI-11 (r = 0.66). CONCLUSION: Patients with HNC experience negative effects in their QoL, related to their impairment in craniomandibular function. Fear of movement, pain intensity, and catastrophism are associated with poorer functionality; relationships that should be considered when attempting to improve health care.

Consensus in acute myeloid leukemia in Mexico.

Acute myeloid leukemia (AML) comprises a heterogeneous group of hematopoietic cell neoplasms of myeloid lineage that arise from the clonal expansion of their precursors in the bone marrow, interfering with cell differentiation, leading to a syndrome of bone marrow failure. AML is a consequence of genetic and epigenetic changes (point mutations, gene rearrangements, deletions, amplifications, and arrangements in epigenetic changes that influence gene expression) in hematopoietic precursor cells, which create a clone of abnormal cells that are capable of proliferating but cannot differentiate into mature hematopoietic cells or undergo programmed cell death. The diagnosis requires more than 20% myeloid blasts in the bone marrow and certain cytogenic abnormalities. Treatment will depend on age, comorbidities, and cytogenetic risk among the most frequent.

La leucemia mieloide aguda (LMA) comprende un grupo heterogéneo de neoplasias de células hematopoyéticas de linaje mieloide que surgen de la expansión clonal de sus precursores en la médula ósea, interfiriendo con la diferenciación celular, lo que conlleva a un síndrome de falla medular. La LMA es una consecuencia de cambios genéticos y epigenéticos (mutaciones puntuales, rearreglos de genes, deleciones, amplificaciones y arreglos en cambios epigenéticos que influyen en la expression del gen) en las células hematopoyéticas precursoras, la cual crea una clona de células anormales que son capaces de proliferar, pero no se pueden diferenciar en células hematopoyéticas maduras ni sufrir una muerte celular programada. El diagnostic requiere más del 20% de blastos mieloides en médula ósea y ciertas anormalidades citogénicas. El tratamiento dependerá de la edad, comorbilidades, riesgo citogenético entre las más frecuentes.

Consenso de leucemia mieloide aguda en México / Mexican consensus in acute myeloid leukemia in Mexico

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Abstract Acute myeloid leukemia (AML) comprises a heterogeneous group of hematopoietic cell neoplasms of myeloid lineage that arise from the clonal expansion of their precursors in the bone marrow, interfering with cell differentiation, leading to a syndrome of bone marrow failure. AML is a consequence of genetic and epigenetic changes (point mutations, gene rearrangements, deletions, amplifications, and arrangements in epigenetic changes that influence gene expression) in hematopoietic precursor cells, which create a clone of abnormal cells that are capable of proliferating but cannot differentiate into mature hematopoietic cells or undergo programmed cell death. The diagnosis requires more than 20% myeloid blasts in the bone marrow and certain cytogenic abnormalities. Treatment will depend on age, comorbidities, and cytogenetic risk among the most frequent.

Mexican Consensus on Hodgkin's Lymphoma.

Hodgkin's lymphoma is due to the clonal transformation of cells originating from B lymphocytes, generating the pathognomonic binucleate Reed-Sternberg cells. Hodgkin's lymphoma is a B cell disease with a bimodal distribution, with higher incidence in adolescence and the third decade of life, showing a second peak in people over 55 years of age. Classic Hodgkin lymphoma cells routinely undergo gene expression reprogramming, as they lose the expression of most of the typical B-cell genes and acquire the expression of multiple genes that are typical of other types of cells in the immune system. The treatment algorithm will depend on whether it is classic or predominantly lymphocytic HL, if it is early stage with unfavorable prognostic markers or not, the initial management regimen, and whether there is bulky disease, among the most relevant variables.

El linfoma de Hodgkin (LH) se debe a la transformación clonal de células originadas en los linfocitos B, lo que genera las células binucleadas patognomónicas de Reed-Sternberg. El LH es una enfermedad de células B con una distribución bimodal, con mayor incidencia en la adolescencia y la tercera década de la vida y un segundo pico en personas mayores de 55 años. Las células del LH clásico habitualmente sufren una reprogramación de la expresión génica, ya que pierden la expresión de la mayoría de los genes típicos de las células B y han adquirido la expresión de múltiples genes que son típicos de otros tipos de células del sistema inmunitario. El algoritmo de tratamiento dependerá si se trata de LH clásico o de predominio linfocítico, si es un estadio temprano con marcadores de pronóstico desfavorables o no, el esquema inicial de manejo y si existe enfermedad voluminosa, entre las variables más relevantes.

Mexican consensus on Hodgkin's lymphoma.

El linfoma de Hodgkin (LH) se debe a la transformación clonal de células originadas en los linfocitos B, lo que genera las células binucleadas patognomónicas de Reed-Sternberg. El LH es una enfermedad de células B con una distribución bimodal, con mayor incidencia en la adolescencia y la tercera década de la vida y un segundo pico en personas mayores de 55 años. Las células del LH clásico habitualmente sufren una reprogramación de la expresión génica, ya que pierden la expresión de la mayoría de los genes típicos de las células B y han adquirido la expresión de múltiples genes que son típicos de otros tipos de células del sistema inmunitario. El algoritmo de tratamiento dependerá si se trata de LH clásico o de predominio linfocítico, si es un estadio temprano con marcadores de pronóstico desfavorables o no, el esquema inicial de manejo y si existe enfermedad voluminosa, entre las variables más relevantes.Hodgkin's lymphoma (HL) is due to the clonal transformation of cells originating from B lymphocytes, generating the pathognomonic binucleate Reed-Sternberg cells. HL is a B cell disease with a bimodal distribution, with higher incidence in adolescence and the third decade of life, showing a second peak in people over 55 years of age. Classic Hodgkin lymphoma cells routinely undergo gene expression reprogramming, as they lose the expression of most of the typical B-cell genes and acquire the expression of multiple genes that are typical of other types of cells in the immune system. The treatment algorithm will depend on whether it is classic or predominantly lymphocytic HL, if it is early stage with unfavorable prognostic markers or not, the initial management regimen, and whether there is bulky disease, among the most relevant variables.

Consenso mexicano de linfoma de Hodgkin / Mexican Consensus on Hodgkin's Lymphoma

Resumen El linfoma de Hodgkin (LH) se debe a la transformación clonal de células originadas en los linfocitos B, lo que genera las células binucleadas patognomónicas de Reed-Sternberg. El LH es una enfermedad de células B con una distribución bimodal, con mayor incidencia en la adolescencia y la tercera década de la vida y un segundo pico en personas mayores de 55 años. Las células del LH clásico habitualmente sufren una reprogramación de la expresión génica, ya que pierden la expresión de la mayoría de los genes típicos de las células B y han adquirido la expresión de múltiples genes que son típicos de otros tipos de células del sistema inmunitario. El algoritmo de tratamiento dependerá si se trata de LH clásico o de predominio linfocítico, si es un estadio temprano con marcadores de pronóstico desfavorables o no, el esquema inicial de manejo y si existe enfermedad voluminosa, entre las variables más relevantes.

Abstract Hodgkin's lymphoma is due to the clonal transformation of cells originating from B lymphocytes, generating the pathognomonic binucleate Reed-Sternberg cells. Hodgkin's lymphoma is a B cell disease with a bimodal distribution, with higher incidence in adolescence and the third decade of life, showing a second peak in people over 55 years of age. Classic Hodgkin lymphoma cells routinely undergo gene expression reprogramming, as they lose the expression of most of the typical B-cell genes and acquire the expression of multiple genes that are typical of other types of cells in the immune system. The treatment algorithm will depend on whether it is classic or predominantly lymphocytic HL, if it is early stage with unfavorable prognostic markers or not, the initial management regimen, and whether there is bulky disease, among the most relevant variables.

Consideraciones terapéuticas en pacientes con leucemia aguda en la era COVID-19 / Therapeutic approach in acute leukemia patients in the COVID-19 era

Resumen La pandemia por enfermedad por coronavirus 2019 (COVID-19), causada por el coronavirus 2 del síndrome respiratorio agudo grave (SARS-CoV-2), ha afectado ya a 180 países. Los pacientes con cáncer/inmunosupresión a mayor edad tienen más riesgo de presentar formas graves de la enfermedad. Los pacientes con leucemia aguda son un reto para el manejo durante la pandemia. Las recomendaciones para el manejo de estos pacientes están basadas en opinión de expertos. Se trata de una población en la que hay que realizar de forma sistemática pruebas de reacción en cadena de la polimerasa para SARS-CoV-2 y diferir en la medida de lo posible la quimioterapia citotóxica en los pacientes que resulten positivos. Por otro lado, algunos de los fármacos frecuentemente utilizados como los corticosteroides, el rituximab o la asparaginasa, pueden potencialmente complicar el curso del COVID-19, por lo que se deberá de considerar diferirlos o ajustarlos en poblaciones de mayor riesgo. De la misma forma, tomando en cuenta las particularidades de cada centro, en ciertos casos se podrá considerar dar preferencia a los esquemas de tratamiento ambulatorios que nos permitan además disminuir el requerimiento transfusional. Finalmente, muchos de los pacientes con leucemia aguda son candidatos para recibir trasplante alogénico de células progenitoras hematopoyéticas (aloTCPH). Debe tomarse en cuenta la limitación de los espacios en terapia intensiva, así como el grado de inmunosupresión derivado del trasplante. La recomendación es no diferir los aloTCPH en los pacientes con una mayor riesgo de recaída de la enfermedad. Más adelante conoceremos las consecuencias de las modificaciones en el tratamiento derivadas de la pandemia sobre la leucemia.

Abstract The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has already affected 180 countries. Older patients and patients with cancer or immunosuppression are at greater risk of severe forms of the disease. Patients with acute leukemia are challenging to manage during the pandemic. Recommendations for the management of these patients are based on expert opinion. This is a population in which polymerase chain reaction tests for SARS-CoV-2 must be performed routinely and cytotoxic chemotherapy should be deferred as far as possible in positive patients. On the other hand, some of the frequently used drugs such as corticosteroids, rituximab or asparaginase, can potentially complicate the course of COVID-19, so consideration should be given to deferring or adjusting them in higher-risk populations. In the same way, considering the particularities of each center, in certain cases it may be reasonable to give preference to outpatient regimens that also allow us to decrease the transfusion requirement. Finally, many of the patients with acute leukemia are candidates to receive allogeneic hematopoietic stem cell transplantation (alloHSCT). The limitation of the spaces in intensive care units must be considered, as well as the degree of immunosuppression derived from the transplant. The recommendation is not to defer alloHSCT in patients with an increased risk of relapse. Later, we will learn about the consequences on of the modifications in treatment on leukemia derived from the pandemic.

Mexican Concensus of Multiple Myeloma.

To identify this increasingly common pathology, known as multiple myeloma (MM), it is necessary to refer to the specific factors that characterize it; to this end, the classic criteria known as CRAB (hyperkalemia, renal failure, anemia, and lytic lesions) are available, in which renal failure is one of the most frequent complications. Recently, three indisputable biomarkers have been described for the diagnostic support for MM, which are: more than 10% of clonal plasma cells in bone marrow or, a biopsy that corroborates the presence of a plasmacytoma, light chain ratio ≥ 100 mg/dL and more than one focal lesion on magnetic resonance imaging. A differential diagnosis for plasma cell leukemia, solitary bone plasmacytoma, and extramedullary plasmacytoma should always be considered. Being this an incurable disease, a lot of research has been done regarding its therapeutic management, whose main objective is the disappearance of plasma cells and the patient clinical improvement. Melphalan was the first drug that showed a benefit in 1958 and afterward, with the addition of a steroid as a second drug, it was possible to improve response rates. Subsequently, different molecules were studied, forming multiple combinations, and achieving better rates of overall survival and progression-free survival. Years later, with the arrival of proteasome inhibitors such as bortezomib, and immunomodulators such as thalidomide and lenalidomide, an important turnaround in the disease has been seen, as deeper responses, more prolonged remissions, and improvement in the quality of life of patients have been achieved. This consensus has the purpose of integrating a group of Mexican specialists and promoting the updating of this pathology.

Para identificar una patología cada vez más común, conocida como mieloma múltiple, es necesario hacer alusión de los factores específicos que la caracterizan. Para ello existen los clásicos criterios conocidos como CRAB (hipercalcemia, insuficiencia renal, anemia y lesiones líticas), siendo la insuficiencia renal una de sus complicaciones más frecuentes. Recientemente se han descrito tres biomarcadores indiscutibles para el apoyo diagnóstico del mieloma múltiple, que son: más del 10% de células plasmáticas clonales en medula ósea o biopsia que corrobora la presencia de un plasmocitoma, relación de cadenas ligeras ≥ 100 mg/dl y más de una lesión focal en resonancia magnética. Se debe tomar siempre en cuenta el diagnóstico diferencial con leucemia de células plasmáticas, plasmocitoma óseo solitario y plasmocitoma extramedular. Al ser una enfermedad incurable, se ha investigado mucho en cuanto al manejo terapéutico, el cual tiene como objetivo principal la desaparición de las células plasmáticas y la mejoría clínica del paciente. El primer fármaco que demostró algún beneficio fue el melfalán en el año 1958 y posteriormente al adicionar un esteroide como segundo fármaco se logró mejorar las tasas de respuesta. Después se fueron estudiando diferentes moléculas, con las que se han realizado múltiples combinaciones, alcanzando mejores tasas de supervivencia global y supervivencia libre de progresión. Años más tarde, con la llegada de los inhibidores de proteosoma como el bortezomib, así como de los agentes inmunomoduladores como la talidomida y la lenalidomida, se presenta un giro importante en la enfermedad, ya que se logran respuestas más profundas, periodo de remisiones más prolongadas y mejoría en la calidad de vida de los pacientes. Este consenso tiene la finalidad de integrar a un grupo de especialistas mexicanos y promover la actualización de esta patología.

Para-Substituted Functionalised Ferrocene Esters with Novel Antibacterial Properties.

INTRODUCTION: Bacterial antibiotic resistance is on rise despite advances in the development of new antibiotics. In an attempt to circumvent resistance, scientists are shifting focus from modifying existent antibiotics to identifying new antibiotic compounds. AIM: To assess the potential antibiotic effects of functionalised ferrocenecarboxylates para-substituted on the phenoxy pendant group to form: 4-fluorophenyl, 4-chlorophenyl, 4-bromophenyl, 4-iodophenyl and 4-(H-pyrrol-1-yl)phenyl. MATERIALS AND METHODS: For this, we employed the Kirby-Bauer disc diffusion method using a collection of nine bacterial species: Staphylococcus aureus, Escherichia coli, Micrococcus luteus, Pseudomonas aeruginosa, Serratia marcescens, Klebsiella pneumoniae, Bacillus subtilis, Proteus vulgaris and Enterobacter aerogenes. RESULTS: The results show that all four-halogen substituted ferrocenecarboxylates 4-fluorophenyl (23.33 µM, 11.66 µM, 5.83 µM), 4-chlorophenyl (10.16 µM, 5.08 µM, 2.54 µM), 4-bromophenyl (9.0 µM, 4.5 µM, 2.25 µM), and 4-iodophenyl (17.12 µM, 8.56 µM, 4.28 µM) exhibited an antibacterial effect by reducing proliferation of Bacillus subtilis. Meanwhile, only 4-bromophenyl (9.0 µM) and 4-chlorophenyl (10.16 µM) ferrocenecarboxylates were able to decrease the growth of Micrococcus luteus. CONCLUSION: Hence, functionalised ferrocenecarboxylates para-substituted with small and simple groups represent a novel class of bio-organometallic compounds with the potential to be used as antibacterial agents.

Le Fort I Approach for Midline Tumors of the Palate.

Midline tumors of the palate may represent a challenge for the maxillofacial surgeon. Their resection and immediate reconstruction could be hindered when a simply intraoral approach is selected. The Le Fort I downfracture approach represents an ideal technique for the management of this tumors, simplifying their resection, ensuring a tumor-free margin, and allowing their reconstruction with a temporal muscle flap. A review of this procedure is presented, highlighting the technical keys and its principal advantages.

DNA electrochemical biosensor for metallic drugs at physiological conditions.

Entrapment of dsSS-DNA into the polypyrrole-polyvinyl sulphonate (dsSS-DNA-PPy-PVS) film over indium-tin-oxide (ITO) coated glass has been designed to detect titanium and platinum drugs, titanocene dichloride and cisplatin. The disposable dsSS-DNA-PPy-PVS/ITO biosensor was characterized by cyclic voltammetry, attenuated total reflectance Infrared spectroscopy and atomic force microscopy. Amperometric studies by cyclic voltammetry using, dsSS-DNA-PPy PVS/ITO biosensor, demonstrated the ability of this biosensor to detect these metallic drugs in millimolar concentration by monitoring the decrease of the guanine oxidation signal as a result of the DNA damage. The concentration range detected for titanocene dichloride is 0.25 to 1.5 mM and for cisplatin is 0.06 to 1.0 mM.

Functionalized ferrocenes: The role of the para substituent on the phenoxy pendant group.

Six ferrocenecarboxylates with phenyl, 4-(1H-pyrrol-1-yl)phenyl, 4-fluorophenyl, 4-chlorophenyl, 4-bromophenyl, 4-iodophenyl as pendant groups were synthesized and fully characterized by spectroscopic, electrochemical and X-ray diffraction methods. The anti-proliferative activity of these complexes were investigated in hormone dependent MCF-7 breast cancer and MCF-10A normal breast cell lines, to determine the role of the para substituent on the phenoxy pendant group. The 4-fluorophenyl ferrocenecarboxylate is inactive in both cell lines while 4-(1H-pyrrol-1-yl)phenyl ferrocenecarboxylate is highly cytotoxic in both cell lines. 4-chlorophenyl and 4-bromophenyl ferrocenecarboxylates have moderate to good anti-proliferative activity in MCF-7 and low anti-proliferative activity on normal breast cell line, MCF-10A whereas the 4-iodophenyl analog is highly toxic on normal breast cell line. The phenyl ferrocenecarboxylate has proliferative effects on MCF-7 and is inactive in MCF-10A. Docking studies between the complexes and the alpha-estrogen receptor (ERα) were performed to search for key interactions which may explain the anti-proliferative activity of 4-bromophenyl ferrocenecarboxylate. Docking studies suggest the anti-proliferative activity of these ferrocenecarboxylates is attributed to the cytotoxic effects of the ferrocene group and not to anti-estrogenic effects.

Mass spectrometry parameters optimization for the 46 multiclass pesticides determination in strawberries with gas chromatography ion-trap tandem mass spectrometry.

Multiclass analysis method was optimized in order to analyze pesticides traces by gas chromatography with ion-trap and tandem mass spectrometry (GC-MS/MS). The influence of some analytical parameters on pesticide signal response was explored. Five ion trap mass spectrometry (IT-MS) operating parameters, including isolation time (IT), excitation voltage (EV), excitation time (ET), maximum excitation energy or "q" value (q), and isolation mass window (IMW) were numerically tested in order to maximize the instrument analytical signal response. For this, multiple linear regression was used in data analysis to evaluate the influence of the five parameters on the analytical response in the ion trap mass spectrometer and to predict its response. The assessment of the five parameters based on the regression equations substantially increased the sensitivity of IT-MS/MS in the MS/MS mode. The results obtained show that for most of the pesticides, these parameters have a strong influence on both signal response and detection limit. Using the optimized method, a multiclass pesticide analysis was performed for 46 pesticides in a strawberry matrix. Levels higher than the limit established for strawberries by the European Union were found in some samples.

Cloning and heterologous expression of Lactobacillus reuteri uroporphyrinogen III synthase/methyltransferase gene (cobA/hemD): preliminary characterization.

PURPOSE OF WORK: To clone, express and characterize uroporphyrinogen III synthase/methyltransferase gene (cobA/hemD) from Lactobacillus reuteri. Some strains of Lb. reuteri produce cobalamin (vitamin B(12)). Cobalamin biosynthesis relies on the sequential action of more than 25 enzymes in a complex metabolic pathway. We have cloned, expressed and characterized the gene in Lb. reuteri that codes for the S-adenosy L: -methionine uroprophyrinogen III methyltransferase/synthase (CobA/HemD), a key bifunctional enzyme in the biosynthesis of cobalamin and other tetrapyrrols.

Synthesis and cytotoxicity studies of steroid-functionalized titanocenes as potential anticancer drugs: sex steroids as potential vectors for titanocenes.

Six titanocenyls functionalized with steroidal esters have been synthesized and characterized by infrared, (1)H, and (13)C NMR spectroscopy and elemental analysis. Among those steroids, dehydroepiandrosterone, trans-androsterone, and androsterone are androgens and pregnenolone is a progesterone precursor. Clionasterol is a natural steroid compound. These steroid-functionalized titanocenyls were tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay for in vitro cytotoxicity for MCF-7 breast cancer and HT-29 colon cancer cells. All complexes exhibited more cytotoxicity than titanocene dichloride. The titanocenyls containing androgen and progesterone derivatives as pendant groups had higher antiproliferative activities than those with cholesterol steroid compounds. Of particular significance is titanocenyl-dehydroepiandrosterone complex, which is 2 orders of magnitude more cytotoxic than titanocene dichloride and also shows much more sensitivity and selectivity for the MCF-7 cell line.

Orbital floor fracture and emphysema after nose blowing.

INTRODUCTION: Orbital floor fractures are usually the result of mechanical trauma. Orbital emphysema tends to develop in fractures affecting the paranasal sinuses and walls of the orbit. CLINICAL CASE: We report the case of a 35-year-old male who suffered an orbital floor fracture with associated orbital emphysema as a result of nose blowing. DISCUSSION: Only one other similar case has been found in the literature.

The complete coenzyme B12 biosynthesis gene cluster of Lactobacillus reuteri CRL1098.

The coenzyme B(12) production pathway in Lactobacillus reuteri has been deduced using a combination of genetic, biochemical and bioinformatics approaches. The coenzyme B(12) gene cluster of Lb. reuteri CRL1098 has the unique feature of clustering together the cbi, cob and hem genes. It consists of 29 ORFs encoding the complete enzymic machinery necessary for de novo biosynthesis. Transcriptional analysis showed it to be expressed as two tandem transcripts of approximately 22 and 4 kb, carrying cobD, cbiABCDETFGHJ, cobA/hemD, cbiKLMNQOP, sirA, hemACBL, and cobUSC, hemD, cobT, respectively. Both transcripts appear to be similarly regulated, and under the conditions assayed are induced in the late-exponential growth phase. Evidence for a regulatory mechanism of negative feedback inhibition by vitamin B(12) itself was observed. Comparative genomics analysis of the coding sequences showed them to be most similar to those coding for the anaerobic coenzyme B(12) pathways previously characterized in a few representatives of the genera Listeria and Salmonella. This contrasts with the trusted species phylogeny and suggests horizontal gene transfer of the B(12) biosynthesis genes. G+C content and codon adaptation index analysis is suggestive that the postulated transfer of these genes was not a recent event. Additional comparative genomics and transcriptional analysis of the sequences acquired during this study suggests a functional link between coenzyme B(12) biosynthesis and reuterin production, which might be implicated in Lb. reuteri's success in colonizing the gastrointestinal tract. This information on gene organization, gene transcription and gene acquisition is relevant for the development of (fermented) foods and probiotics enriched in B(12).

Pseudovitamin B(12) is the corrinoid produced by Lactobacillus reuteri CRL1098 under anaerobic conditions.

We have reported previously on the ability of Lactobacillus reuteri to produce a compound with vitamin B(12) activity. Here we report on the chemical characterisation of this corrinoid-like molecule. High performance liquid chromatography coupled to an ultraviolet diode array detector, mass spectrometry and nuclear magnetic resonance spectroscopy has enabled us to identify the compound as Coalpha-[alpha-(7-adenyl)]-Cobeta-cyanocobamide or pseudovitamin B(12). This molecule differs from cobalamin in the alpha-ligand, where it has adenine instead of 5,6-dimethylbenzimidazole bound in a alpha-glycosidic linkage to C-1 of ribose. L. reuteri is the first lactic acid bacterium in which the production of a cobalamin-like molecule has been identified and the first microorganism reported to produce exclusively pseudo-B(12).

Molybdenocene-oligonucleotide binding study at physiological pH using NMR spectroscopy and cyclic voltammetry.

The self-complementary oligonucleotide CGCATATATGCG was used as a model to establish the binding interactions of antitumor molybdenocene dichloride and DNA. The free dodecamer was first characterized using (1)H, NOESY, and DQF-COSY NMR experiments, which enable to pinpoint the guanines and adenines as well as the cytosines and thymines signals in the aromatic region. Molybdenocene dichloride was characterized in saline and buffer solutions as function of pH by (1)H NMR spectroscopy. In 10mM NaCl/D(2)O solution at pH of 6.5 and above, Cp(2)Mo(OD)(D(2)O)(+) is in equilibrium with its dimeric species, [Cp(2)Mo(mu-OH)(2)MoCp(2)](2+). In 25mM Tris/4mM NaCl/D(2)O at physiological pH, a new stable species is formed, coordinated by the buffer, Tris(hydroxymethyl)aminomethane. The interactions of molybdenocene dichloride species with CGCATATATGCG were studied at different pH. At pH 6.5, in 4mM NaCl/D(2)O solution, (1)H NMR spectra of CGCATATATGCG exhibit downfield shifts in the signals associated mainly to adenines and guanines, upon addition of molybdenocene dichloride. At pH 7.4, in 25mM Tris/4mM NaCl/D(2)O, molybdenocene species causes broadening and small downfield shifts to the purines and pyrimidine signals, suggesting that molybdenocene dichloride can get engaged in binding interactions with the oligonucleotide in a weak manner. (31)P NMR spectra of these interactions at pH 7.4 showed no changes associated to Mo(IV)-OP coordination, indicating that molybdenocene-oligonucleotide binding interactions are centered, most likely, on the bases. Cyclic voltammetry titration showed a 4.9% of molybdenocene-oligonucleotide interaction. This implicates that possible binding interactions with DNA are weak.