Pruebas bioquímicas para el diagnóstico de anemia megaloblástica / Biochemical tests for diagnosis of megaloblastic anemias / Testes bioquímicos para o diagnóstico de anemia megaloblástica

Es intención de este trabajo hacer un breve repaso sobre el metabolismo de la Vitamina B12 y del Folato o Vitamina B9. Estas dos vitaminas hidrosolubles juegan un papel importante en el metabolismo celular. Son cofactores de reacciones metabólicas de transferencia de grupos monocarbonados, esenciales para el mantenimiento de la vida. Además se describen las nuevas determinaciones de laboratorio, se evalúan cuáles son los estudios necesarios para arribar a un correcto diagnóstico del paciente con Anemia Macrocítica (AM), su etiología y cómo muchas drogas de uso frecuente en medicina producen AM. Se realiza también la evaluación del conjunto de metodologías que se pueden efectuar como rutina en el laboratorio especializado en hematología y se propone un algoritmo para el diagnóstico del paciente con AM.

The aim of this article is to make a little review on Vitamin B12 and Folate or Vitamin B9 metabolism. These hydrosoluble vitamins have a very important role in cell metabolism. They are cofactors in metabolic reactions of methyl group transfer, essential for life maintaining. Furthermore, new laboratory tests are described, and it is evaluated which the necessary studies are to arrive at a correct diagnosis for macrocytic anemia (MA) patients, their etiology, and how many drugs frequently used in medicine originate MA. Also, the set of methodologies that can be carried out routinely in the laboratory specialized in hematology is evaluated. Finally, a diagnosis algorithm to detect MA in patients is proposed.

Este trabalho visa a realizar uma breve revisão sobre o metabolismo da Vitamina B12 e do Folato ou Vitamina B9. Estas duas vitaminas hidrossolúveis têm um papel importante no metabolismo celular. São cofatores de reações metabólicas de transferência de grupos monocarbonados, essenciais para manter a vida. Também são descritas novas determinações de laboratório, avaliam-se quais são os estudos necessários para chegar a um diagnóstico correto do paciente com Anemia Macrocítica (AM), sua etiologia e de qué maneira muitas drogas de uso frequente em medicina produzem AM. Realiza-se também a avaliação do conjunto de metodologias que podem realizar-se como rotina no laboratório especializado em hematologia e se propõe um algoritmo para o diagnóstico do paciente com AM.

Efeito da administração de propileno glicol e cobalto associado à vitamina B12 sobre o perfil metabólico e a atividade enzimática de ovelhas da raça Santa Inês no periparto / Effect of propylene glycol, cobalt and vitamin B12 on the metabolic profile and enzymatic in Santa Inês ewes in peripartum

(AU)O presente estudo teve por objetivo avaliar a influência da administração de propileno glicol e cobalto associado à vitamina B12 sobre o perfil metabólico e a atividade enzimática de ovelhas da raça Santa Inês no período do periparto. Foram utilizadas 18 ovelhas prenhes, pesando em torno de 40kg. Aproximadamente 30 dias antes da data prevista para o parto foram separadas de maneira aleatória em três grupos e administrados os suplementos conforme a seguir: (G1/n=6) grupo que recebeu propileno glicol (30mL por via oral diariamente); (G2/n=6) grupo que recebeu cobalto (1mg de cloreto de cobalto a 1%, via oral diariamente) associado a vitamina B12 (2mg via intramuscular, semanalmente) e (G3/n=6) grupo controle. As amostras de sangue das ovelhas para avaliação do perfil metabólico e enzimático (glicose, β-hidroxibutirato-BHB, NEFA, proteína total, albumina, uréia, creatinina, AST, GGT, FA e CK) foram colhidas 30 dias antes da data prevista para o parto, uma semana antes (ante-parto), no parto, às 24h, 72h, 5 dias, 15 dias e 30 dias após o parto. Não foi observado cetonúria nos momentos que antecederam ao parto. A administração dos suplementos não influenciou sobre o perfil metabólico, protéico e energético, assim como não houve comprometimento hepático das ovelhas no período do periparto.(AU)

The aim of this study was to evaluate the influence of the administration of propylene glycol and cobalt associated with vitamin B12 on the metabolic profile and enzymatic activity of Santa Inês ewes in the peripartum period. A total of 18 pregnant ewes, weighing around 40kg were used. Approximately 30 days before the expected date of delivery were randomly separated into three groups and administered supplements as follows: (G1/n = 6) group received propylene glycol (30mL orally daily); (G2/n = 6) group receiving cobalt (1mg cobalt chloride 1%, orally daily) associated with vitamin B12 (2mg intramuscular weekly) and (G3/n = 6) control group. Blood samples from ewes to evaluate the enzymatic and metabolic profile (glucose, β-hydroxybutyrate, BHB, NEFA, total protein, albumin, urea, creatinine, AST, GGT, ALP and CK) were taken 30 days before the date set for delivery, one week before (ante partum), delivery at 24h, 72h, 5 days, 15 days and 30 days after delivery. ketonuria was not observed in pre partum. The administration of supplements had no effect on the metabolic profile, protein and energy, and no liver disorders was observed in peripartum.(AU)

Comparison between serum holotranscobalamin and total vitamin B12 as indicators of Vitamin B12 status

This study aims to assess the usefulness of serum holotranscobalamin [holo TC], the fraction of vitamin B12 that is available for tissue uptake, compared with total vitamin B12 in patients investigated for vitamin B12 disorders. Serum samples were randomly selected from 76 patients [48females, 28 males; age range 12-69 years] referred to the Clinical Biochemistry Laboratory, Royal Hospital for the assessment of vitamin B12 status. For each patient, serum total vitamin B12 was determined by chemiluminescent microparticle immunoassay on Architect 2000 analyzer and holo TC[active vitamin B12] level was determined by microparticle enzyme immunoassay on Axsym analyzer [both from Abbott, USA]. Comparison of the data was conducted to reflect the mean, standard deviation [SD] and correlation coefficient between the two groups. The mean [SD] for serum holo TC and total vitamin B12 were 46.5[32.2] pmol/L and 316.3[165.6] pmol/L respectively. There was a significant correlation between holo TC and total vitamin B12 [r=0.765, P<0.001] and the regression equation was expressed as; y= a+bx [i.e: holot TC = 1.5+0.14 total vitamin B12]. Also, the results were assessed for any misclassification when comparing holo TC and the total vitamin B12 in terms of whether each or both values agree or disagree for classifying the patients as having normal or abnormal [low or high] results, based on the cut-off thresholds of the kit's quoted reference range for holo TC of 9-123 pmol/L and for total vitamin B12 of 140-600 pmol/L. Accordingly, in69 [90.8%] samples, there was a parallel agreement/ classification of results, both being normal or abnormal. In 61 [80.4%] patients, both results were normal, whereas in 4 [5.2%] patients, both results were high, and in 4 [5.2%] patients both results were low. However, in 7[9.8%] cases, there was disagreement/ misclassification of results; 6 [7.8%] patients, holo TC was normal while total vitamin B12 was low, and in 1 [1.4%] patient, holo TC was normal while total vitamin B12 was low, and in 1 [1.4%] patient, holo TC was normal while total vitamin B 12 was high. It can be recommended that holo TC and total vitamin B 12, alone and in combination, have almost equal diagnostic efficiency reflector of vitamin B 12 status. Further comparison studies based on a gold standard method for classifying vitamin B 12 status are worth considering

Development and validation of PCR, PLS, and TLC densitometric methods for the simultaneous determination of vitamins B1, B6 and B12 in pharmaceutical formulations

This work represents the simultaneous determination of thiamine hydrochloride [B1], pyridoxine hydrochloride [B6] and cyanocobalamine [B12] by two different methods namely spectrophotometry multivariate calibration and densitometry. The spectrophotometric numerical method depends on the use of spectrophotometric data coupled to PLS and PCR multivariate calibration methods for the simultaneous determination of [B1] and [B6] in the presence of [B12] in laboratory prepared mixtures and commercial tablets. A calibration set was prepared, where the three vitamins were modeled using a full factorial 23 with three center points experimental design. This calibration set was used to build the PLS and PCR models. The models were validated by testing their predictive ability on a validation set where low RMSEP, RSEP% were obtained for both models. Figures of merit were determined using the net analyte signal concept. The proposed models were applied successfully to simultaneous determination of B1 and B6 in presence of a low concentration of B12 in pharmaceutical dosage forms that contain simple excipients. The TLC densitometric method was based on the use of a developing system of chloroform: ethanol: water: acetic acid solution [2: 8: 2: 0.5 v/v] to separate the three vitamins. The separated spots were scanned at 242nm, 291nm and 360nm for B1, B6 and B12 respectively. The proposed method was applied successfully to simultaneous determination of the three vitamins in their pure powder form in the range 0.1-1.5 [micro g/spot], 0.5-3.5 [micro g/spot], 0.1-1.5 [micro g/spot] for B1, B6, and B12 respectively and in their pharmaceutical formulations

High frequency of suboptimal serum vitamin B12 level in adults in Jordan

To assess the prevalence of functional vitamin B12 deficiency status in an adult Jordanian seemingly healthy population. We carried out this study in the Department of Physiology, Faculty of Medicine, Jordanian University of Science and Technology, Jordan from September 2004 to January 2005. We included a randomly selected sample of 216 healthy adult volunteers [male 124, female 92, aged 19-50 years] from north Jordan. We carried out the measurement of hematological variables by Micros 60-OT Analyzer. We measured the serum vitamin B12 by microparticle enzyme immunoassay and serum folate by ion-capture assay on an AxSYM Analyzer. We found suboptimal [<222 pg/ml] serum levels of vitamin B12 in 104 [48.1%] [male 64, female 40] subjects. The mean serum vitamin B12 level of male in all volunteers was 238.8 +/- 97.3 pg/ml, not significantly different [p=0.24] from that of female [261.8 +/- 101.6 pg/ml]. The mean serum values of vitamin B12 of male in the suboptimal group [168.3 +/- 36.4 pg/ml; range 90-221] were not significantly different from that of female [178.2 +/- 27.5 pg/ml; range 113-217] [p=0.31]. Of the suboptimal group, 30 subjects [28.8%] had hyper-segmented neutrophils, 38 subjects [36.5%] had low mean corpuscular volume and 8 subjects [7.7%] had sub-optimal serum folate levels. This study revealed that there was a high frequency of suboptimal serum vitamin B12 level, which is an early sign of negative B12 balance

Deficiencia de hierro, ácido fólico y vitamina B12 en mujeres mexicanas urbanas en edad reproductiva / Iron, folic acid and vitamin B12 deficiencies, in mexican urban women at childbearing age

Objetivo: Evaluar el estado de nutrición en hierro, folato y vitamina B12 y determinar la prevalencia de anemia en un grupo de mujeres no embarazadas, no lactando, que habitan en la Ciudad de México y que acuden a un servicio de salud por presentar esterilidad. Material y métodos: Se estudió un grupo de 117 mujeres que fueron atendidas en la consulta externa de un hospital de enseñanza, especializado en la atención de la mujer en edad reproductiva. Las mujeres fueron evaluadas en una sola ocasión, y previo consentimiento, se determinaron sus niveles de hemoglobina, ferritina, folato eritrocitario y vitamina B12 en plasma. Ninguna de ellas consumió suplementos vitamínicos o sustancias que pudieran interferir con el metabolismo de los nutrimentos evaluados.Resultados: La prevalencia de anemia fue cercana a 12 por ciento (hemoglobina < 130 g/L) y las deficiencias específicas aisladas más frecuentes fueron: ácido fólico 28 por ciento, y deficiencia de hierro 20 por ciento. Sólo 5.1 por ciento de las mujeres presentaron deficiencia de vitamina B12. Las deficiencias de folato y hierro, incrementaron significativamente el riesgo de presentar anemia (Razón de momios 5.37, IC 95 por ciento 1.55-18.54 y 3.8 IC 95 por ciento 1.02-14.60, respectivamente). Conclusiones: Existe un porcentaje significativo de anemia y deficiencia de ácido fólico y hierro, así como de vitamina B12 en mujeres en edad reproductiva con esterilidad.

The source and content of vitamin B12 in the tempehs.

Vitamin B12 contents were determined on 10 commercial tempeh samples purchased from various markets in Jakarta, Indonesia. A relatively high vitamin B12 content was found, i.e., 19 ng/g (ranges from 1.8 to 41.4 ng/g). As soybeans contain no vitamin B12, the amount of vitamin in the tempeh must therefore be derived from the other sources during the fermentation process. The tempeh prepared in the laboratory by inoculation of the commercial starter into the sterile soybean contained a much higher amount of vitamin B12, 127 ng/g (ranges from 122 to 136 ng/g). Pure mold and a single species of bacteria were isolated from the starter and commercial tempehs. Pure mold did not produce vitamin B12 in the sterile broth, soybean and medium used for vitamin B12 production. Only the isolated bacteria, identified as K. pneumoniae, could produce vitamin B12 in those substrates. The presence of mold did not significantly enhance or inhibit the vitamin B12 production by K. pneumoniae. It was, therefore, concluded that K. pneumoniae, the bacteria contaminated during the process of tempeh production, was responsible for the vitamin B12 production.