Prevalence of Listeria monocytogenes in Idiazabal cheese / Prevalencia de Listeria monocytogenes en queso Idiazabal

Introduction: Raw-milk cheese has been identified in risk assessment as a food of greater concern to public health due to listeriosis. Objective: To determine the prevalence and levels of Listeria monocytogenes in semi-hard Idiazabal cheese manufactured by different producers in the Basque Country at consumer level. Methodology: A total of 51 Idiazabal cheese samples were obtained from 10 separate retail establishments, chosen by stratified random sampling. Samples were tested using the official standard ISO procedure 11290-1 for detection and enumeration methods. Results and conclusion: All cheese samples tested negative for L. monocytogenes. However, 9.8% tested positive for Listeria spp., different from L. monocytogenes. Positive samples came from two brands, two were natural and three were smoked. The presence of Listeria spss. suggests that the cheese making process and the hygiene whether at milking or during cheese making could be insufficient (AU)

Introducción: Listeria monocytogenes se ha asociado a quesos elaborados a partir de leche cruda, lo que supone un importante riesgo de salud pública debido a la listeriosis. Objetivo: Estudiar la prevalencia y los niveles de L. monocytogenes en quesos Idiazabal semi-curados de distintos productores del País Vasco, a nivel de consumidor. Metodología: Se analizaron 51 muestras de queso Idiazabal procedentes de 10 establecimientos de venta al público; el muestreo fue aleatorio y estratificado. Los análisis se hicieron según el método de detección y de enumeración del procedimiento estandarizado ISO 11290-1. Resultados y conclusión: Todas las muestras dieron negativo para L. monocytogenes. Sin embargo, el 9,8% dio positivo para Listeria spp., distinta de L. monocytogenes. Las muestras positivas procedían de dos marcas, dos eran quesos naturales y tres ahumados. La presencia de Listeria spss. sugiere que el procesado del queso y la higiene durante el ordeño o durante la fabricación podría ser insuficiente (AU)

Prevalence of Listeria monocytogenes in Idiazabal cheese.

INTRODUCTION: Raw-milk cheese has been identified in risk assessment as a food of greater concern to public health due to listeriosis. OBJECTIVE: To determine the prevalence and levels of Listeria monocytogenes in semi-hard Idiazabal cheese manufactured by different producers in the Basque Country at consumer level. METHODOLOGY: A total of 51 Idiazabal cheese samples were obtained from 10 separate retail establishments, chosen by stratified random sampling. Samples were tested using the official standard ISO procedure 11290-1 for detection and enumeration methods. RESULTS AND CONCLUSION: All cheese samples tested negative for L. monocytogenes. However, 9.8% tested positive for Listeria spp., different from L. monocytogenes. Positive samples came from two brands, two were natural and three were smoked. The presence of Listeria spss. suggests that the cheese making process and the hygiene whether at milking or during cheese making could be insufficient.

Characterization of hepatitis B virus genotypes in chronically infected patients

Las mutaciones genómicas presentes durante la transcripción reversa del virus de la hepatitis B (VHB) podrían explicar su variabilidad genéticay ser la causa de la existencia de ocho genotipos distintos que presentan una distribución geográfica diferente. Los objetivos principalesdel presente trabajo fueron determinar la prevalencia de los genotipos del virus de la hepatitis B en pacientes con hepatitis crónica B y buscarla relación entre los genotipos y los factores de riesgo de transmisión con respecto al estado del HBeAg. Se analizaron 14 muestras desuero utilizando el kit INNO-LIPA HBV Genotyping assay. El genotipo D fue el más prevalente (64,3%), seguido del genotipo A (28,6%). Enuna muestra se detectó una coinfección (genotipos D/E) que fue confirmada mediante secuenciación. Todos los pacientes, excepto uno, presentaronHBeAg negativo y anti-HBe positivo. Con respecto a los factores de riesgo de transmisión del VHB, en la mitad de los casos se desconocían;en la otra mitad se observaron transmisiones sexuales, mediante transfusión, verticales e intrafamiliares. Estos resultados demuestranque el genotipo D es el más prevalente en nuestro hospital, seguido del genotipo A. Por otra parte, no hemos encontrado relación entreel estado del HBeAg y el genotipo implicado en la infección(AU)

Genomic mutations occurring during reverse transcription of hepatitis B virus (HBV) could explain its genetic diversity and account for 8genetically distinct genotypes that are geographically distributed quite differently. The main objectives of this study were to determine theprevalence of hepatitis B virus genotypes in patients with chronic hepatitis B and to see if there was a relationship between genotypes andrisk factors for transmission based on HBeAg status. A total of 14 serum samples were analyzed using INNO-LIPA HBV genotyping assay.Genotype D was the most prevalent (64.3%) followed by genotype A (28.6%). There was one case of co-infection (D/E genotypes) that wasconfirmed by PCR sequencing. All patients except one were HBeAg-negative and anti-HBe-positive. The risk factors for HBV transmission wereunknown in half of the cases; in the other half, sexual, transfusion, maternal or interfamilial transmission were observed. The results showthat genotype D is the most prevalent genotype in our hospital, followed by genotype A. On the other hand, no relationship was found betweenHBeAg status and genotype(AU)

Characterization of hepatitis B virus genotypes in chronically infected patients.

Genomic mutations occurring during reverse transcription of hepatitis B virus (HBV) could explain its genetic diversity and account for 8 genetically distinct genotypes that are geographically distributed quite differently. The main objectives of this study were to determine the prevalence of hepatitis B virus genotypes in patients with chronic hepatitis B and to see if there was a relationship between genotypes and risk factors for transmission based on HBeAg status. A total of 14 serum samples were analyzed using INNO-LIPA HBV genotyping assay. Genotype D was the most prevalent (64.3%) followed by genotype A (28.6%). There was one case of co-infection (D/E genotypes) that was confirmed by PCR sequencing. All patients except one were HBeAg-negative and anti-HBe-positive. The risk factors for HBV transmission were unknown in half of the cases; in the other half, sexual, transfusion, maternal or interfamilial transmission were observed. The results show that genotype D is the most prevalent genotype in our hospital, followed by genotype A. On the other hand, no relationship was found between HBeAg status and genotype.

Variabilidad del virus de la hepatitis C e inhibición de las rutas del interferón / Hepatitis C virus variability and interferon-mediated pathway inhibition

El presente estudio tiene como objetivo principal determinar la hipotética relación entre la variabilidad de la región PePHD (relacionada con la codificación de un pseudosustrato para una enzima viral) del virus de la hepatitis C y la evolución de la terapia con interferón, con el fin de determinar si la aparición de mutaciones en esta región es el factor determinante de la respuesta al tratamiento. El valor que expresa la variabilidad es la detección de un elevado número de cuasiespecies. Para ello se emplearon técnicas ya utilizadas en estudios anteriores, como la transcripción inversa, la doble amplificación (RT-PCR anidada) y SSCP (Single-Strand Conformation Polymorphism). Se analizaron 24 enfermos, todos ellos infectados crónicamente por el virus de la hepatitis C. Se clasificaron en tres grupos diferentes dependiendo de la respuesta a la terapia: 8 pacientes con respuesta sostenida, 8 pacientes con respuesta parcial y 8 pacientes no respondedores. Todos los casos analizados presentaron un grado de heterogeneidad bajo. Este resultado se obtuvo independientemente de otros factores relacionados con la falta de respuesta, como son la edad y el sexo de los pacientes o el genotipo del virus. El hecho de que la secuencia sea tan poco variable indica que es una región funcionalmente importante para la persistencia viral. Se necesitan estudios más profundos para determinar el papel que realmente tiene esta región en las interacciones de la célula y el virus (AU)

[Hepatitis C virus variability and interferon-mediated pathway inhibition]. / Variabilidad del virus de la hepatitis C e inhibicion de las rutas del interferon.

The most important aim of this study was to describe the hypothetical relationship between the PePHD region variability (related to the synthesis of a cellular enzyme pseudosubstrate) of the hepatitis C virus and the response of patients to interferon therapy. This interaction could be a determining factor in the antiviral effect of interferon. All samples (from 24 patients with chronic hepatitis C infection) were analyzed using a previously described method based on RT-PCR and nested PCR mediated by single-strand conformation polymorphism assay (SSCP). The patients were divided into three groups with respect to the response to therapy: 8 patients with sustained response, 8 patients with transient response and 8 nonresponders. In all samples a low genetic heterogeneity pattern was detected, which was independent of other factors involved in the lack of response to treatment, such as age, sex or viral genotype. This genetic homogeneity is an indirect indication of the importance of the region on viral persistence. However, more studies are needed to evaluate the real role of this sequence on the interaction between cells and the virus.

Cuasiespecies virales y su implicación en el tratamiento antiviral / Viral quasispecies and their implications in antiviral therapy

El objetivo del presente estudio fue analizar la relación entre las cuasiespecies en la región HVR1 del virus de la hepatitis C y la evolución del tratamiento para poder determinar si la complejidad genética puede actuar como un factor predictivo de la respuesta al tratamiento. Para el análisis de las muestras se realizó una doble amplificación (nested RT-PCR) del genoma viral seguida de SSCP (Single-Strand Conformation Polymorphism). Se analizaron 12 pacientes con hepatitis C crónica que fueron clasificados en tres grupos diferentes: tres pacientes con respuesta sostenida, tres pacientes con respuesta parcial y seis pacientes no respondedores. Los pacientes respondedores presentaron un patrón de baja complejidad genética, mientras que tres de los pacientes no respondedores y uno de los pacientes con respuesta parcial presentaron un patrón de elevada complejidad. Respecto al resto de los pacientes con respuesta parcial, se produjo la aparición de nuevas bandas, modificándose así su patrón de complejidad genética. Por lo tanto, la falta de respuesta al tratamiento podría estar relacionada con una elevada heterogeneidad, mientras que la presencia de una baja complejidad genética sería una condición indispensable para responder al tratamiento con interferón. Sin embargo, el escaso número de pacientes no permite afirmar que el patrón de cuasiespecies sea un factor predictivo de la respuesta, por lo que es necesario realizar estudios posteriores más amplios. (AU)

[Viral quasispecies and their implications in antiviral therapy]. / Cuasiespecies virales y su implicación en el tratamiento antiviral.

The aim of this study was to evaluate the relationship between the quasispecies in the HVR1 region of the hepatitis C virus and treatment evolution in order to determine whether genetic complexity is predictive of response to interferon therapy. The samples were analyzed by nested RT-PCR-mediated single-strand conformation polymorphism assay (SSCP). Twelve patients with chronic hepatitis C were studied and divided into three groups: three patients with sustained response, three patients with transient response and six nonresponders. The patients in the sustained response group showed a low genetic complexity pattern. By contrast, in three nonresponders and in one patient with transient response, the SSCP assay revealed a high complexity pattern. With regard to the remaining patients with transient response, new SSCP bands appeared, thereby modifying their genetic complexity pattern. Therefore, nonresponse to interferon treatment could be related to the presence of a high genetic complexity pattern, while the detection of a low genetic complexity pattern is necessary for a positive response to interferon therapy. Due to the limited number of patients involved in this study, it was not possible to predict the response to interferon based on the genetic complexity pattern. Larger studies are therefore required.

Interaction of the alpha-helices of apolipophorin III with the phospholipid acyl chains in discoidal lipoprotein particles: a fluorescence quenching study.

Quenching of tryptophan fluorescence by nitroxide-labeled phospholipids and nitroxide-labeled fatty acids was used to investigate the lipid-binding domains of apolipophorin III. The location of the Trp residues relative to the lipid bilayer was investigated in discoidal lipoprotein particles made with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine and five different single-Trp mutants of apoLp-III. A comparison of the quenching efficiencies of phospholipids containing nitroxide groups at the polar head, and at positions 5 and 16 of the sn-2 acyl chain, indicated that the protein is interacting with the acyl chains of the phospholipid along the periphery of the bilayer of the discoidal lipoprotein. N-Bromosuccinimide readily abolished 100% of the fluorescence of all Trp residues in the lipid-bound state. Larger quenching rates were observed for the Trp residues in helices 1, 4, and 5 than for those located in helices 2 and 3, suggesting differences between the interaction of these two groups of helices. However, the extent of Trp fluorescence quenching observed in lipoproteins made with any of the mutants was comparable to that reported for deeply embedded Trp residues, suggesting that all Trp residues interact with the phospholipid acyl chains. This study provides the first experimental evidence of a massive interaction of the alpha-helices of apoLp-III with the phospholipid acyl chains in discoidal lipoproteins. The extent of interaction deduced is consistent with the apolipoprotein adopting a highly extended conformation.

Essential role of the conformational flexibility of helices 1 and 5 on the lipid binding activity of apolipophorin-III.

It has been recently postulated that the conformational flexibility of helices 1 and 5 of Locusta migratoria apoLp-III could play an important role in early steps of binding of this apolipoprotein to a lipid surface (Soulages, J. L., and Arrese, E. L. (2000) J. Biol. Chem. 275, 17501-17509). To test this model, we have designed a double Cys mutant in which a disulfide bond linking helices 1 and 5 could be formed, resulting in an apolipoprotein with reduced conformational flexibility of its N- and C-terminal helices. Substitution of Thr(18) and Ala(147) by Cys residues provided a protein that under nonreducing conditions was fully oxidized. The far-UV CD spectra of this mutant in the reduced and oxidized states indicated that their secondary structures were identical to the structure of the wild type recombinant apoLp-III, which contains no Cys residues. Near-UV CD studies confirmed the formation of a disulfide bond and the absence of structural perturbations. The lipid binding activity of the reduced mutant, as determined by its ability to form discoidal lipoproteins, was nearly identical to that of the wild type protein. Contrarily, the disulfide form of the mutant was not able to form discoidal lipoproteins with liposomes of either dimirystoylphosphatidylcholine or dimyristoylphosphatidylglycerol. It is concluded that the separation of the helices 1 and 5 constitutes one of the key steps along the complex pathway for the formation of the final apolipoprotein lipid-bound state. It is inferred that the conformational flexibility of helices 1 and 5 is a key property of apoLp-III, allowing the exposure of hydrophobic protein regions and the interaction of the hydrophobic faces of the amphipathic alpha-helices with the lipoprotein lipid surface.

Diacylglycerol transport in the insect fat body: evidence of involvement of lipid droplets and the cytosolic fraction.

In this report we show the existence of a distinct pool of fat body diacylglycerol (DG) that can be distinguished from the bulk DG. This is a dynamic pool of DG that uses FA entering the fat body from the hemolymph, whereas the bulk DG uses the fatty acids stored in the fat body fat droplets. Using a dual labeling technique, it was possible to compare the effect of hormone-stimulated DG synthesis and secretion on the distribution of radiolabeled FA among the lipids of the dynamic pool (short-term radiolabeling), with the hormonal effect on the total complement of fat body lipids (long-term radiolabeling). We observed that, whereas DG represents 2% to 3% of the fat body lipid mass, about 20% of the short-term radiolabeled lipids are represented by DG. Stimulation of lipolysis produces a fast decrease in the fraction of short-term radiolabeled DG, whereas there is an increase in the mass of fat body DG. The subcellular distribution of bulk DG showed that its majority (62%) was in the fat cake whereas only 2.9% was in the cytosol. On lipolysis stimulation, the largest changes in specific activities of newly synthesized DG were detected in the cytosol and the fat cake, suggesting that newly synthesized DG localized in the lipid droplets and the cytosol is preferentially mobilized.

Lipid storage and mobilization in insects: current status and future directions.

In this paper we review the current status of research on fatty acid absorption and conversion to diacylglycerol in the midgut. We further discuss how diacylglycerol may leave the midgut and associate with lipophorin in hemolymph. We review the present understanding of the role of the lipid transfer particle and lipophorin receptors in lipid delivery between lipophorin and tissues. Finally, we discuss recent studies on the mobilization of diacylglycerol from the fat body in response to adipokinetic hormone. Several suggestions for exciting areas of future research are described.

Fluorescence spectroscopy of single tryptophan mutants of apolipophorin-III in discoidal lipoproteins of dimyristoylphosphatidylcholine.

The structure of the exchangeable apolipoprotein, apolipophorin-III from Locusta migratoria, apoLp-III, is described as a bundle of five amphipathic alpha-helices. To study the interaction of each of the helices of apoLp-III with a lipid surface, we designed five single-Trp mutants, each containing a Trp residue in a different alpha-helix. The Trp residues were located in the nonpolar domains of the amphipathic alpha-helices. The kinetics of the spontaneous interaction of the mutants with dimyristoylphosphatidylcholine (DMPC) indicated that all mutants behaved as typical exchangeable apolipoproteins. Circular dichroism in the far-UV indicated that all proteins have a high and similar helical content in the lipid-bound state. The interaction of the Trp residues with the lipid surface was investigated in recombinant lipoprotein particles made with DMPC. The properties of the Trp residues were investigated by fluorescence spectroscopy. These studies showed major changes in the spectroscopic properties of the Trp residues upon binding to lipid. These changes are observed with all single-Trp mutants, indicating that a major conformational change, which affects the properties of all helices, takes place upon binding to lipid. The position of the fluorescence maximum, the quenching efficiency of acrylamide as determined by steady-state and time-resolved fluorescence, and the fluorescence lifetimes of the single-Trp mutants suggest that helices 1, 4, and 5 interact with the nonpolar domains of the lipid. The properties of the Trp in helices 2 and 3 suggest that these helices adopt a different binding configuration than helices 1, 4, and 5. Helices 2 and 3 appear to be interacting with the polar headgroups of the phospholipids or constitute a different domain that does not interact with the lipid surface.

Allosteric effectors and trehalose protect larval Manduca sexta fat body glycogen phosphorylase B against thermal denaturation.

In this paper we assessed the ability of modulators of the activity of glycogen phosphorylase b from the fat body of larval Manduca sexta to stabilize the enzyme against thermal denaturation. This approach has allowed us to distinguish between modulators that stabilize the enzyme, presumably through some conformational effect, from those that do not affect thermal stability. For example, 5'-AMP and 5'-IMP are both positive modulators of the enzyme and the K(m)s for AMP and IMP were similar, 0.71 and 1.09 mM, respectively. However, the V(max) for AMP (123 nmol/mg/min) was 10 times higher than the value found for IMP (12.5 nmol/mg/min) and AMP increased the thermal stability of glycogen phosphorylase b, however IMP did not increase the enzyme's thermal stability. Indeed, IMP decreased both the allosteric activation of the enzyme by AMP and the thermal protection conferred by AMP. The allosteric inhibitors ADP and ATP, which in vertebrate phosphorylase bind to the same site as AMP, both increased the thermal stability of the enzyme, however with less efficiency than AMP. Inorganic phosphate increased thermal stability, but glycogen and amylose did not. Glycerol, at 600 mM, protected the enzyme against thermal inactivation, whereas sorbitol at the same concentration did not show any effect. Among the polyols tested, trehalose was the most effective in conferring thermal stability. In fact, in the presence of 20 mM AMP and 600 mM trehalose, 90% of the enzyme activity remained after 20 min at 60 degrees C.

Dynamics and hydration of the alpha-helices of apolipophorin III.

Apolipophorin III (apoLp-III) is an exchangeable apolipoprotein whose structure is represented as a bundle of five amphipathic alpha-helices. In order to study the properties of the helical domains of apolipophorin III, we designed and obtained five single-tryptophan mutants of Locusta migratoria apoLp-III. The proteins were studied by UV absorption spectroscopy, time-resolved and steady-state fluorescence spectroscopy, and circular dichroism. Fluorescence anisotropy, near-UV CD and solute fluorescence quenching studies indicate that the Trp residues in helices 1 (N-terminal) and 5 (C-terminal) have the highest conformational flexibility. These two residues also showed the highest degree of hydration. Trp residues in helices 3 and 4 display the lowest mobility, as assessed by fluorescence anisotropy and near UV CD. The Trp residue in helix 2 is protected from the solvent but shows high mobility. As inferred from the properties of the Trp residues, helices 1 and 5 appear to have the highest conformational flexibility. Helix 2 has an intermediate mobility, whereas helices 3 and 4 appear to constitute a highly ordered domain. From the configuration of the helices in the tertiary structure of the protein, we estimated the relative strength of the five interhelical interactions of apoLp-III. These interactions can be ordered according to their apparent stabilizing strengths as: helix 3-helix 4 > helix 2-helix 3 > helix 4-helix 1 approximately helix 2-helix 5 > helix 1-helix 5. A new model for the conformational change that is expected to occur upon binding of the apolipoprotein to lipid is proposed. This model is significantly different from the currently accepted model (Breiter, D. R., Kanost, M. R., Benning, M. M., Wesemberg, G., Law, J. H., Wells, M. A., Rayment, I., and Holden, M. (1991) Biochemistry 30, 603-608). The model presented here predicts that the relaxation of the tertiary structure and the concomitant exposure of the hydrophobic core take place through the disruption of the weak interhelical contacts between helices 1 and 5. To some extent, the weakness of the helix 1-helix 5 interaction would be due to the parallel arrangement of these helices.

Detection of HGV in serum and peripheral blood mononuclear cells of maintenance haemodialysis patients.

The aim of the present study was to investigate the prevalence of hepatitis G virus (HGV) and also hepatitis C virus (HCV) infections in maintenance haemodialysis patients, and to identify extrahepatic sites as HGV reservoirs. HGV RNA was detected in the serum of 6/61 (10%) patients and in the peripheral blood mononuclear cells of 2/61 (3%) patients (one of whom was serum negative). These findings suggest that lymphoid cells constitute an extrahepatic HGV reservoir. HCV RNA was detected in 7/61 (11%) patients. Five of these patients (71%) were identified as carrying HCV genotype 1b. Co-infection with HCV and HGV was detected only in one patient. Haemodialysis patients are at risk for HGV infection, by nosocomial routes or via transfusions. HGV itself does not seem to be an important cause of hepatitis since all six HGV RNA positive patients not co-infected by HCV or HBV showed normal ALT values.

Late disappearance of hepatitis C virus RNA from peripheral blood mononuclear cells in patients with chronic hepatitis C in sustained response after alpha-interferon therapy.

OBJECTIVE: We aimed to investigate the modifications of HCV RNA (genomic and antigenomic strands) in peripheral blood mononuclear cells (PBMCs) of long-term responder patients to alpha-interferon therapy, and their usefulness as criteria of definitive HCV eradication. METHODS: We studied 10 patients with chronic hepatitis C with > 1 yr of sustained response after alpha-interferon therapy (normal alanine aminotransferase [ALT] and negative serum HCV RNA). Serum HCV RNA and genotyping were determined. Approximately 2 and 4 yr after completion of treatment we investigated the presence of HCV RNA (genomic and antigenomic strands) in PBMCs. Eight of 10 patients were rebiopsed 2 yr after discontinuation of treatment. RESULTS: The mean follow-up was 46.6 +/- 4.6 months (range, 39-51 months). In this period, all patients remained in sustained response. In the first determination, all patients had HCV RNA genomic strands and two patients had antigenomic strands detectable in PBMCs. Two years later only two patients had genomic and none had antigenomic strands detectable. After 4 yr of sustained response, eight of 10 patients lost HCV RNA from PBMCs. CONCLUSIONS: In the long-term follow-up, the majority of patients with chronic hepatitis C with sustained response after alpha-interferon therapy progressively lost HCV RNA from PBMCs. This determination in PBMCs is not a predictor of response.

Calcium and cAMP are second messengers in the adipokinetic hormone-induced lipolysis of triacylglycerols in Manduca sexta fat body.

We have previously shown that stereospecific hydrolysis of stored triacylglycerol by a phosphorylatable triacylglycerol-lipase is the pathway for the adipokinetic hormone-stimulated synthesis of sn -1, 2-diacylglycerol in insect fat body. The current series of experiments were designed to determine whether cAMP and/or calcium are involved in the signal transduction pathway for adipokinetic hormone in the fat body. After adipokinetic hormone treatment, cAMP-dependent protein kinase activity in the fat body rapidly increased and reached a maximum after 20 min, suggesting that adipokinetic hormone causes an increase in cAMP. Forskolin (0.1 micrometer), an adenylate cyclase activator, induced up to a 97% increase in the secretion of diacylglycerol from the fat body. 8Br-cAMP (a membrane-permeable analog of cAMP) produced a 40% increase in the hemolymph diacylglycerol content. Treatment with cholera toxin, which also stimulates adenylate cyclase, induced up to a 145% increase in diacylglycerol production. Chelation of extracellular calcium produced up to 70% inhibition of the adipokinetic hormone-dependent mobilization of lipids. Calcium-mobilizing agents, ionomycin and thapsigargin, greatly stimulated DG production by up to 130%. Finally, adipokinetic hormone caused a rapid increase of calcium uptake into the fat body. Our findings indicate that the action of adipokinetic hormone in mobilizing lipids from the insect fat body involves both cAMP and calcium as intracellular messengers.

Distribution of HCV genotypes in patients infected by different sources.

To determine the distribution of hepatitis C virus (HCV) genotypes in our population within the Basque country, 58 HCV-infected patients were analysed. The predominant HCV genotype among subjects infected by blood transfusions (n = 9) and surgical procedures (n = 14) was 1b (88 and 50%, respectively). On the other hand, genotype 3a was the most common among intravenous drug users (n = 16), with data statistically significant (p < 0.0001). There were 18 patients (31%) with unknown risk factors, twelve of whom (66.7%) were infected with genotype 1b. Patients infected with genotype 1b were older than patients infected with genotype 3a (p < 0.0001). There existed a relationship between the HCV genotype and the source of infection.

Adipokinetic hormone-induced lipolysis in the fat body of an insect, Manduca sexta: synthesis of sn-1,2-diacylglycerols.

The pathway for the adipokinetic hormone-stimulated synthesis of sn-1,2-diacylglycerols in the adult Manduca sexta fat body was studied. Adult fat body lipids were labeled by feeding 5th instar larvae either with [9,10(n)-3H]oleic acid or [1(3)-3H] glycerol and after 32 days insects at the adult stage were used. This long-term prelabeling led to labeled fat body acylglycerols in which triacylglycerols comprised the main radioactive lipid component (95.5%), regardless of the radiolabeled compound used. Because the distribution of radioactivity among the lipid classes was very close to the mass distribution of the fat body lipid subspecies, it was concluded that homogeneous labeling of fat body lipids was obtained. After adipokinetic hormone treatment, an accumulation of radioactivity in the sn-1,2-diacylglycerol fraction was the only significant change found in the distribution of radioactivity among fat body lipids. The size of diacylglycerol pool increased 280% 60 min after adipokinetic hormone stimulation, whereas the fatty acid, monoacylglycerol and phosphatidic acid pool sizes remained constant. These results support the hypothesis that adipokinetic hormone-stimulated synthesis of sn-1,2-diacylglycerol in the fat body involves stereospecific hydrolysis of the triacylglycerol stores.