Valor pronóstico de las isoenzimas de LDH en pacientes con linforma no hodgkin / Prognostic value of LDH isoenzymes in patients with non-Hodgkin linforma

La enzima lactato deshidrogenasa (LDH) es un factor pronóstico en Linfoma No Hodgkin (LNH). El objetivo del trabajo consistió en evaluar prospectivamente el valor pronóstico de las isoenzimas de LDH en pacientes con LNH. Se estudiaron 67 pacientes de primera consulta con diagnóstico de LNH, sin tratamiento previo, VIH negativo y sin otras enfermedades, tiempo promedio de seguimiento 30 meses (rango 3-48 meses). Las muestras de suero se recolectaron previas al tratamiento. La LDH total (LDHT) e isoenzimas de LDH se determinaron respectivamente por método cinético y electroforesis de proteínas en gel de agarosa. Se procesaron muestras de 122 controles sanos para establecer los valores de referencia de las isoenzimas de LDH. 49(73%) LNH agresivos y 18(27%) LNH indolentes y según el Índice Pronóstico Internacional (IPI), 60 (90%) bajo riesgo y 7(10%) alto riesgo. Las isoenzimas LDH1, LDH2, LDH3, LDH4 y LDH5 presentaron niveles absolutos significativamente elevados en 25 (37%), 29 (43%), 32 (48%), 20 (39%) y 11 (16%) de los casos respectivamente (p<0,0001). La actividad porcentual de LDH4 en los pacientes con LNH agresivos fue significativamente superior respecto al grupo de LNH indolentes (p=0,01). En el análisis univariado, valores absolutos elevados de LDH1 se asociaron significativamente con una sobrevida global disminuida (p=0,0064) en el grupo total de pacientes. LDH1 conservó su valor pronóstico aún en el grupo de pacientes con valores normales de LDHT (p=0,04). En pacientes con LNH agresivos, valores elevados de LDHT e IPI alto riesgo se asociaron significativamente con una menor sobrevida global (p<0,05). En el análisis multivariado la LDHT e IPI resultaron factores pronósticos independientes de la sobrevida. Alteraciones específicas del patrón de isoenzimas de LDH sugieren la relación de LDH4 con la biología del tumor y su actividad proliferativa en LNH agresivos y el valor pronóstico de LDH1 como factor adverso de la sobrevida en el análisis univariado.

Lactate dehydrogenase (LDH) is a prognostic factor in non-Hodgkin lymphoma (NHL). Our objective was to evaluate prospectively the prognostic value of LDH isoenzymes in patients with NHL. We studied 67 newly diagnosed NHL patients, previously untreated, HIV-negative and free from other disease, median follow-up of 30 month (range 3-48 month). Before starting treatment serum samples were collected for the determination of total LDH (LDHT) and LDH isoenzymes that were respectively assayed by kinetic method and protein electrophoresis in agarose gel. In order to set reference values of LDH isoenzymes samples from122 healthy controls were processed. Results: 49(73%) of the patients were aggressive NHL and 18(27%) indolent NHL and according to the International Prognostic Index (IPI), 60(90 %) low risk and 7(10%) high risk. High absolute values of LDH1, LDH2, LDH3, LDH4 and LDH5 isoenzymes were significantly elevated in 25 (37%), 29 (43%), 32 (48%), 20 (39%) and 11 (16%) of cases respectively (p<0,0001). The percentage value of LDH4 activity in aggressive NHL patients was significantly higher compared to indolent NHL group (p=0,01). In univariate analysis increased LDH1 absolute values were significantly associated with decreased overall survival in the total group of patients (p = 0.0064). LDH1 remained a prognostic factor for survival even when considering the group of patients with normal serum LDHT values (p = 0.04). In patients with aggressive NHL increased values of LDHT and high risk IPI were significantly associated with decreased overall survival (p<0.05). In a multivariate analysis LDHT and IPI score were independent prognostic factor for survival.

Presence of bound substrate in lactate dehydrogenase from carp liver.

While attempting to purify UDP-galactose 4-epimerase from carp liver extract at pH 8.0, it was observed that the preparation even after dialysis could reduce NAD to NADH, interfering epimerase assay. The NAD reduction activity and the epimerase were co-eluted in a series of chromatographic steps. Mass spectrometric analysis of semi-purified fraction revealed that carp liver lactate dehydrogenase (LDH) contained bound lactate which was converted to pyruvate in the presence of NAD. The enzyme-bound lactate and the association with epimerase stabilized LDH from trypsin digestion and thermal inactivation at 45°C by factors of 2.7 and 4.2 respectively, as compared to substrate-free LDH. LDH and epimerase do not belong to any one pathway, but are the rate-limiting enzymes of two different pathways of carbohydrate metabolism. Typically, strongly associated enzymes work in combination, such as two enzymes of the same metabolic pathway. In that background, co-purification of LDH and epimerase as reloaded in this study was an unusual phenomenon.

Antigen capture immuno-chromatographic strip format in detecting parasite-specific lactate dehydrogenase to diagnose malaria in non-immune patients

Several rapid diagnostic test devices [RDT] based on detection of malaria antigen in the whole blood were developed. OptiMal test the presence of parasite-specific lactate dehydrogenase [LDH] enzyme using three monoclonal antibodies was used. Two monoclonal antibodies were pan-specific and recognized all malaria species. The third one was specific only for Plasmodium falciparum. The parasite antigens were detected using an antigen-capture immunochromatographic strip format. One hundred-nine malaria positive and 730 malaria negative cases diagnosed by microscopy were included. 75/109 were P. flaciparum 26 as P. vivax, 3 P. malariae and 5 mixed infection of P. falciparum and P. vivax. The RDT showed a low sensitivity [85%, 95% Confidence Interval [CI], 79-92%] with a much lower sensitivity in detecting species other than P. falciparum as well as in mixed infections. The sensitivity was 50% for less than 200 parasites/micro. The sensitivity of OptiMal for P. falciparum was 87% [95% CI,79-94], 81% [95% CI,66-96] for P. vivax, and failed with P. malariae. Mixed infections were misdiagnosed as P. falciparum. The sensitivity of OptiMal was quite good in detecting both P. falciparum and P. vivax [98%; 95%C1, 97-99 and 100%; 95%CI, 100-100 respectively] and 99% [95%CT, 98-99] for all species. The positive and negative ratio for all malaria species was: [+LR= 62.3, -LR= 0.01]; for P. falciparum [+LR =3 8.9, -LR=0.01] and for P. vivax [+LR=0.8077/0,-LR=0.2]. The test value to assess drug resistance in post treatment days was discussed

Modulation of T cell functions by sperm-specific lactate dehydrogenase: fluorescence analysis of immune competent cells and local graft versus host reaction.

Immune responses to a well-defined sperm-specific isogenic lactate dehydrogenase-C4 (LDH-C4) have been studied in C57Bl/Ks (H-2d) mice after immunization through intra-rectal route. Presence of anti-LDH-C4-antibodies in the sera of females immunized in presence or absence of adjuvant suggested that the immune system of mice becomes exposed to sperm antigens following intrarectal insemination. LDH-C4 primed lymphocytes from both males and females, when transferred in F1 hybrids, suppressed stimulation index of local graft versus host reaction. However, contrary to females, male counterparts which did not elicit measurable anti-LDH-C4-antibody titer, showed the presence of a higher proportion of Ly2+ and Ia+ fluorescence labelled cells in the spleen of LDH-C4 administered mice. Results suggest that males are more susceptible for immune suppression of T cell functions through generation of T suppressor cells. Sex differences in relation to immune deviation by intra-rectal administration of sperm-specific LDH-C4 in mice and their consequences in AIDS and AIDS-related complex diseases are described.

Purificaçö parcial da desidrogenase lática eritrocitária / Partial purification of erythrocyte lactate dehydrogenase

A purificaçäo parcial da desidrogenase lática (LDH) de glóbulos vermelhos humanos vencidos foi efetuada utilizando-se, basicamente, a DEAE-celulose equilbrada em tampäo fosfato 10mM, pH 7,6, em que a hemoglobina näo se liga, mas a desidrogenase lática se adere à resina. A eluiçäo foi feita em gradiente fosfato 10-100mM e as fraçöes onde as atividades de LDH estavam presentes foram reunidas, dialisadas e novamente submetidas a cromatografia e eluiçäo. A preparaçäo final mostrou ausência de piruvato quinase e das enzimas da glicólise, com exceçäo de negligível contaminaçäo com monofosfogliceromutase e glutationa peroxidase, também presentes na preparaçäo Sigma L2881 obtida de coraçäo de suíno