Methylphenidate has long-lasting metaplastic effects in the prefrontal cortex of adolescent rats.

Methylphenidate (MPH) is widely used as a "nootropic" agent and in the treatment of disorders of attention, and has been shown to modulate synaptic plasticity in vitro. Here we present in vivo evidence that this MPH-induced metaplasticity can last long after the end of treatment. MPH (0, 0.2, 1 and 5mg/kg) was administered daily to male rats from postnatal day 42 for 15 days. The animals were tested daily in a radial maze. Long-term potentiation (LTP), a marker of neural plasticity, was induced in vivo in the prefrontal cortex after 2-3h, 15-18 days or 5 months without treatment. The behavioral performance of the 1mg/kg group improved, while that of animals that had received 5mg/kg deteriorated. In the 1 and 5mg/kg groups LTP induced 2-3h after the last MPH treatment was twice as large as in the controls. Further, 15-18 days after the last MPH administration, in groups receiving 1 and 5mg/kg, LTP was about fourfold higher than in controls. However, 5 months later, LTP in the 1mg/kg group was similar to controls and in the 5mg/kg group LTP could not be induced at all. No significant changes of LTP were seen in the low-dose group of animals (0.2mg/kg). Thus, firstly, doses of MPH that improve learning coincide approximately with those that augment LTP. Secondly, MPH-induced increases in LTP can last for several weeks, but these may disappear over longer periods or deteriorate at high doses.

MDMA (3,4-Methylenedioxymethamphetamine) Analogues as Tools to Characterize MDMA-Like Effects: An Approach to Understand Entactogen Pharmacology.

Besides stimulants and hallucinogens, whose psychotropic effects are shared by many structurally related molecules exhibiting different efficacies and potencies in humans, the phenylisopropylamine MDMA (3,4-methylenedioxymethamphetamine, XTC, "Ecstasy") is the prototypical representative of a separate class of psychotropic substance, able to elicit the so-called entactogenic syndrome in healthy humans. This reversible altered state of consciousness, usually described as an "open mind state", may have relevant therapeutic applications, both in psychotherapy and as a pharmacological support in many neuropsychiatric disorders with a high rate of treatment failure. Nevertheless, a comprehensive and systematic exploration of the structure-activity relationships associated with entactogenic activity has remained incomplete and controversial, highlighting the possibility that MDMA might represent a pharmacological rarity in the field of psychotropics. As the latter is still an open question, the pharmacological characterization of MDMA analogues remains the logical strategy to attempt the elucidation of the structural requirements needed to elicit typical MDMA-like effects. Intriguingly, almost no experimental evidence supports the existence of actual MDMA analogues that truly resemble the whole pharmacological profile of MDMA, probably due to its complex (and partially not fully understood) mechanism of action that includes a disruption of monoaminergic neurotransmission. The present review presents a brief summary of the pharmacology of MDMA, followed by the evidence accumulated over the years regarding the characterization of classical structurally related MDMA analogues in different models and how this state of the art highlights the need to develop new and better MDMA analogues.

Analysis of coenzyme Q(10) in lymphocytes by HPLC-MS/MS.

Coenzyme Q(10) (CoQ(10)) deficiency syndromes are potentially treatable disorders. Skeletal muscle is the most widely accepted tissue for their study, but sampling is an invasive procedure. Cultured skin fibroblasts seem to improve the biochemical diagnosis, but their growth requires a certain period of time. Our aim was to set up a minimally invasive, fast and reliable analytical procedure to measure CoQ(10) in lymphocytes, to prevent any delay in diagnosing primary CoQ(10) deficiency. HPLC-MS/MS analysis of CoQ(10) showed high sensitivity and specificity. The reference range was established in apparently healthy volunteers (n=33); the mean of CoQ(10) in lymphocytes was 107nmol/g protein (95% confidence interval: 105-120) and 2.0nmol/UCS (95% confidence interval: 2.06-2.46). Therefore, the range was narrower when normalized to units of citrate synthase (UCS) than when normalized to grams of protein. The method was linear from 0.01 to 1µM with a good precision and sensitivity (limit of quantification 0.01µM). Intra-assay and inter-assay coefficients of variation were lower than 13%. Recovery was higher than 95%. In our hands, lymphocytes seem to be a reliable matrix as they reflect intracellular content of CoQ(10). In addition, they can be obtained by a minimally invasive procedure (venipuncture).

Mild clinical and biochemical phenotype in two patients with PMM2-CDG (congenital disorder of glycosylation Ia).

Phosphomannomutase 2 deficiency (PMM2-CDG) patients may present as mild phenotypes, with the cerebellum frequently involved. In those cases, false-negative results in screening may occur when applying conventional biochemical procedures. Our aim was to report two patients with a diagnosis of PMM2-CDG presenting with mild clinical phenotype. Patient 1-at 9 months of age, she presented with just psychomotor delay, tremor, hypotonia, and slight lipodystrophy. Patient 2-she presented at 8 months of age with psychomotor delay, hand stereotypes, hypotonia, convergent bilateral strabismus, and tremor but no lipodystrophy. Routine biochemical parameters including blood count, clotting factors, proteins, and thyroid hormone were normal in both cases. Cranial MRI evidenced mild cerebellar atrophy with moderate vermis hypoplasia. In case 1, sialotransferrin pattern showed very slightly increased disialotransferrin with no asialotransferrin, and in case 2, the transferrin pattern was impaired in the first study but nearly normal in the second. Nevertheless, in all the samples, quantification of the patterns obtained by capillary zone electrophoresis analysis gave results out of the control range. High residual PMM2 activity was observed in both cases and the genetic analysis showed that patient 1 was heterozygous for c.722G>C (p.C241S) and c.368G>A (p.R123Q) mutations, and patient 2 showed the c.722G>C and the c.470T>C (p.F157S) mutations in the PMM2 gene. We would like to stress the importance of the use of sensitive semiquantitative methods of screening for CDG in order to achieve early identification of patients with mild phenotypes. Intentional tremor was an atypical but remarkable clinical feature in both cases, and the global cerebellar atrophy with vermis hypoplasia reinforced the early clinical suspicion of a PMM2-CDG disease.

The molecular landscape of phosphomannose mutase deficiency in iberian peninsula: identification of 15 population-specific mutations.

PMM2-CDG is an autosomal recessive disorder and the most frequent form of congenital disorder of N-glycosylation, with more than 100 mutations identified to date. Sixty-six patients from 58 unrelated families were diagnosed as PMM2-CDG (CDG-Ia) based on clinical signs or because of a previous affected sibling. They all presented a type 1 serum transferrin isoform pattern, and, in most cases, the disease was confirmed by determining PMM2 activity in fibroblasts and/or lymphocytes. Residual PMM2 activity in fibroblasts ranged from not detectable to 60% of the mean controls. DNA and RNA were isolated from fresh blood or fibroblasts from patients to perform molecular studies of the PMM2 gene, resulting in the identification of 30 different mutations, four of them newly reported here (p.Y102C, p.T118S, p.P184T, and p.D209G). From these 30 mutations, 15 have only been identified among Iberian PMM2-CDG patients. As in other Caucasian populations, p.R141H was the most frequent mutation (24 alleles, prevalence 20.6%), but less than in other European series in which this mutation represents 35-43% of the disease alleles. The next frequent mutations were p.D65Y (12 alleles, prevalence 10.3%) and p.T237M (9 alleles, prevalence 7.6%), while p.F119L and p.E139K, the most frequent changes in Scandinavian and French populations, respectively, were not found in our patients. The most common genotype was [p.R141H] + [p.T237M], and four homozygous patients for p.Y64C, p.D65Y, p.P113L, and p.T237M were detected. The broad mutational spectrum and the diversity of phenotypes found in the Iberian populations hamper genotype-phenotype correlation.

The role of human demographic history in determining the distribution and frequency of transferase-deficient galactosaemia mutations.

Classical or transferase-deficient galactosaemia is an inherited metabolic disorder caused by mutation in the human Galactose-1-phosphate uridyl transferase (GALT) gene. Of some 170 causative mutations reported, fewer than 10% are observed in more than one geographic region or ethnic group. To better understand the population history of the common GALT mutations, we have established a haplotyping system for the GALT locus incorporating eight single nucleotide polymorphisms and three short tandem repeat markers. We analysed haplotypes associated with the three most frequent GALT gene mutations, Q188R, K285N and Duarte-2 (D2), and estimated their age. Haplotype diversity, in conjunction with measures of genetic diversity and of linkage disequilibrium, indicated that Q188R and K285N are European mutations. The Q188R mutation arose in central Europe within the last 20 000 years, with its observed east-west cline of increasing relative allele frequency possibly being due to population expansion during the re-colonization of Europe by Homo sapiens in the Mesolithic age. K285N was found to be a younger mutation that originated in Eastern Europe and is probably more geographically restricted as it arose after all major European population expansions. The D2 variant was found to be an ancient mutation that originated before the expansion of Homo sapiens out of Africa.

Mutational study in the PDHA1 gene of 40 patients suspected of pyruvate dehydrogenase complex deficiency.

We screened for PDHA1 mutations in 40 patients with biochemically demonstrated PDHc deficiency or strong clinical suspicion, and found changes with probable pathological significance in 20. Five patients presented new mutations: p.A169V, c.932_938del, c.1143_1144 ins24, c.1146_1159dup and c.510-30G> A, this latter is a new undescribed cause of exon 6 skipping. Another four mutations have been found, and previously reported, in our patients: p.H113D, p.P172L, p.Y243del and p.Y369Q. Eleven patients presented seven known mutations: p.R127Q, p.I166I, p.A198T, p.R263G, p.R302C, p.R378C and c.1142_1145dup. The latter three were found in more than one unrelated patient: p.R302C was detected in a heterozygous girl and a mosaic male, p.R378C in two males and finally, c.1142_1145dup in three females; only one in 20 mothers was found to be a carrier (p.R263G). Apart from those 20 patients, the only alteration detected in one girl with clear PDHc and PDH-E1 deficiency was the silent change c.396A> C (p.R132R), and other eight PDHc deficient patients carry combinations of known infrequent polymorphisms that are overrepresented among our 20 unsolved patients. The importance of these changes on PDH activity is unclear. Investigations in the other PDHc genes are in course in order to elucidate the genetic defect in the unresolved patients.

PDH E1ß deficiency with novel mutations in two patients with Leigh syndrome.

Most cases of pyruvate dehydrogenase complex (PDHc) deficiency are attributable to mutations in the PDHA1 gene which encodes the E(1)α subunit, with few cases of mutations in the genes for E(3), E3BP (E(3) binding protein), E(2) and E(1)-phosphatase being reported. Only seven patients with deficiency of the E(1)ß subunit have been described, with mutations in the PDHB gene in six of them. Clinically they presented with a non-specific encephalomyopathy. We report two patients with new mutations in PDHB and Leigh syndrome. Patient 1 was a boy with neonatal onset of hyperlactataemia, corpus callosum hypoplasia and a convulsive encephalopathy. After neurological deterioration, he died at age 5 months. Autopsy revealed the characteristic features of Leigh syndrome. Patient 2, also a boy, presented a milder clinical course. First symptoms were noticed at age 16 months with muscular hypotonia, lactic acidosis and recurrent episodes of somnolence and transient tetraparesis. MRI revealed bilateral signal hyperintensities in the globus pallidus, midbrain and crura cerebri. PDHc and E(1) activities were deficient in fibroblasts in patient 1; in patient 2 PDHc deficiency was found in skeletal muscle. Mutations in PDHA1 were excluded. Sequencing of PDHB revealed a homozygous point mutation (c.302T>C), causing a predicted amino acid change (p.M101T) in patient 1. Patient 2 is compound heterozygote for mutations c.301A>G (p.M101V) and c.313G>A (p.R105Q). All three mutations appear to destabilize the E(1) enzyme with a decrease of both E(1)α and E(1)ß subunits in immunoblot analysis. To our knowledge, these patients with novel PDHB mutations are the first reported with Leigh syndrome.

Secondary disorders of glycosylation in inborn errors of fructose metabolism.

Adamowicz and colleagues raised the alert in 2007 about patients with atypical hereditary fructose intolerance (HFI) primarily misdiagnosed as CDG Ix. We describe a girl with neonatal hypertonia, facial trismus, absent swallowing and coughing reflexes, gastro-oesophageal reflux and sporadically elevated Krebs cycle metabolites and lactate. At 14 months microcephaly and hepatomegaly were noted, with hypertransaminasaemia but normal blood coagulation, glucose, phosphate, and absent urinary reducing substances. Neurological impairment persisted. Because of hepatic and neurological abnormalities with developmental delay, Tf IEF was performed and showed a severe type 1 pattern, resulting in a wrong diagnosis of CDG. Subsequently, an aversion to fruits suggested HFI, confirmed by the finding of ALDOB mutations (p.A150P/p.N335K). The girl improved with fructose-free diet, but liver cirrhosis led to hepatic transplantation. She is now 7 years old with good evolution; facial trismus and hypertonia reversed, but microcephaly persists. Transferrin MALDI-TOF MS characterization revealed underoccupation of glycosylation sites and glycan abnormalities, which reversed with dietary treatment. High maternal fructose concentrations might have caused neonatal abnormalities. Although in our patient's mother there is no fructose accumulation at present, it is possible that increased ingestion of fruits and vegetables during pregnancy, together with her heterozygosity, caused an accumulation of fructose that finally affected the fetus. We also describe slightly abnormal transferrin isoelectric focusing and MALDI-TOF MS patterns of intact transferrin and N-glycans in a fructose-1,6-bisphosphatase (FBP1)-deficient patient. While HFI is a well-known cause of secondary CDG, we found no reports of abnormal transferrin isoelectric focusing patterns in FBP1 deficiency and we introduce this condition as a possible secondary cause for altered transferrin isoelectric focusing.

Encefalopatía aguda necrosante familiar o recurrente desencadenada por infecciones / Infection-triggered familial or recurrent acute necrotizing encephalopathy

La encefalopatía aguda necrosante (EAN) es una encefalopatía rápidamente progresiva que se presenta en niños por lo demás normales asociada a infecciones víricas comunes, como influenza y parainfluenza. La mayoría de los casos son esporádicos y no recurrentes, y se han descrito en pacientes asiáticos, aunque también se han comunicado casos aislados en países occidentales. Recientemente se han encontrado mutaciones en heterocigosis de un gen que codifica una proteína componente del poro nuclear, denominada Ran Binding Protein 2 (RANBP2), en un número significativo de pacientes con esta forma familiar o recurrente de EAN.A continuación se describe una familia española con la forma familiar y recurrente de EAN, en la que el estudio de secuenciación del gen RANBP2 fue negativo. Las mutaciones del gen RANBP2 no son el único alelo que determina susceptibilidad para el desarrollo de la forma familiar o recurrente de EAN (AU)

Acute necrotizing encephalopathy (ANE) presents in children after common viral infections. Most cases of ANE are non-familial and non-recurrent and have been mainly reported in Asian patients, although ANE affects children worldwide. Recently, missense mutations in the gene encoding the nuclear pore protein Ran Binding Protein 2 (RANBP2) have been found in several families with familial or recurrent cases of ANE. We describe a Spanish family with familial and recurrent ANE without mutations in RANBP2. Mutations in RANBP2 are not the sole susceptibility alleles for familial or recurrent ANE (AU)

[Infection-triggered familial or recurrent acute necrotizing encephalopathy]. / Encefalopatía aguda necrosante familiar o recurrente desencadenada por infecciones.

Acute necrotizing encephalopathy (ANE) presents in children after common viral infections. Most cases of ANE are non-familial and non-recurrent and have been mainly reported in Asian patients, although ANE affects children worldwide. Recently, missense mutations in the gene encoding the nuclear pore protein Ran Binding Protein 2 (RANBP2) have been found in several families with familial or recurrent cases of ANE. We describe a Spanish family with familial and recurrent ANE without mutations in RANBP2. Mutations in RANBP2 are not the sole susceptibility alleles for familial or recurrent ANE.

Long-term evolution of eight Spanish patients with CDG type Ia: typical and atypical manifestations.

Congenital disorder of glycosylation Ia (CDG-Ia) is a metabolic disease with a broad spectrum of clinical signs, including recently described mild phenotypes. Our aim was to describe the clinical presentation and follow-up of eight CDG-Ia patients highlighting atypical features and aspects of evolution of the disease. CDG diagnosis was confirmed by enzymatic analysis of phosphomannomutase (PMM2) and molecular studies of the PMM2 gene. Four neonates presented with cerebral haemorrhage (1), failure to thrive (2) and non-immune hydrops (1) and a fatal course to death (2); pathological examination of the brain in one case revealed olivopontocerebellar atrophy of prenatal origin. During infancy failure to thrive, coagulopathy and hepatopathy were the most significant causes of morbidity, but these disappeared after the first years of life in most patients. Three patients are currently in their 20s; they present mental retardation and severe motor impairment but no acute decompensations were noticed after the first decade of life. They do not present spinal or thoracic deformities otherwise observed in patients from northern countries. A 10-year-old patient who manifested gastrointestinal dysfunction in early childhood showed normal neurodevelopment. Mutation analysis of the PMM2 gene showed great variability, with all patients being compound heterozygous for two different mutations. Long-term evolution in our patients indicates that CDG-Ia is a stable systemic and neurological condition after the first decade of life. The diverse phenotypes and atypical manifestations in our series may be due to their genetic heterogeneity.

Calidad en genética bioquímica prenatal / Quality in prenatal biochemical genetics

Para diagnosticar enfermedades metabólicas hereditarias(EMH), tanto postnatales como prenatalmente, se empleanlos recursos de la genética bioquímica, que se basanmayoritariamente en el estudio en fluidos biológicos y tejidos de productos génicos (proteínas) y de metabolitos específicos que sean demostrativos o estén directamente relacionados con la pérdida de función de un gen. Las EMH, debido a sus bajas prevalencias individuales, entran en la categoría de enfermedades raras o minoritarias, pero se han descrito centenares de ellas y en general son enfermedades abrumadoras y a menudo letales. Debido a ello y a las dificultadesde tratamiento, su diagnóstico prenatal es muy relevante.En el presente artículo se resumen unos conocimientosmínimos indispensables sobre su complejidad y losmedios del laboratorio para llegar al diagnóstico, a fin de demostrar la importancia que tiene en el diagnóstico prenatal la labor de reunir la máxima información posible acerca del caso índice y de los padres (heterocigotos). Seguidamente se trata el tema de la calidad de los laboratorios y de laspruebas o ensayos de genética bioquímica, incluyendo elcontrol europeo específico de la ERNDIM, el proyecto Eurogentest de la CE para la armonización, validación y estandarización de pruebas genéticas, la Ley 14/2007 de 3 de julio de 2007 de investigación biomédica que define y regula el marco para la realización de pruebas genéticas en investigación y en asistencia y las Normas ISO para la certificación y acreditación de los laboratorios. El artículo finaliza con unrecordatorio de las técnicas y materiales fetales utilizados para el diagnóstico prenatal de las EMH

For the diagnosis of Inherited disorders of metabolism(IDM), postnatal as well as prenatal, we need the resources of Biochemical genetics, which are mainly based in the studies in biological fluids and tissues of the gene products (proteins) and specific metabolites, directly related or demonstratives of a gene function impairment. Because of the very low individual prevalence of IDM, they are consideredrare diseases, but it had been described hundreds ofthem, being moreover overwhelming and often lethal diseases. These facts, together with difficulties for treatment made prenatal diagnosis very relevant. In this paper, there are summarised some essential knowledge on the complexity of IDM and the resources of the laboratory for its diagnosis, in order to show how it is important for the prenatal diagnosis, to collect all the possible information about the index case and the parents (heterozygous). Next, issues are the quality of the biochemical genetics tests and laboratories,including the specific ERNDIM QAP; the FP6 projectEurogentest for the harmonization, validation andstandardization of diagnostic genetic testing; the Spanish bill 14/2007 on biomedical research, that among other issues provides for genetic testing for research as well as for medical care purposes and some concepts on ISO norms for the certification/accreditation of laboratories. Finally, there is a reminder of the technology and foetal materials suitable for the prenatal diagnosis of IDM

Secondary alteration of the transferrin isoelectric focusing pattern in a case of bacterial meningitis.

Congenital disorders of glycosylation (CDG) are a group of inherited defects in the synthesis and processing of the linked glycans of glycoproteins and other glycoconjugates. The phenotypic spectrum presents wide variability, and clinical diagnosis is not reliable in most cases. Isoelectric focusing (IEF) of serum transferrin is widely used as a tool to detect CDG. We describe a paediatric patient presenting an altered serum transferrin pattern due to a secondary disorder of glycosylation caused by pneumococcal meningitis (Streptococcus pneumoniae, serotype 19A). During admission, brain CT scan and MRI showed acute ischaemic lesions in brain frontotemporal parenchyma, and enlarged subarachnoidal spaces in the frontal area resembling a chronic injury. This led us to screen for inborn errors of metabolism potentially associated with these findings (homocystinuria, glutaric aciduria, CDG syndromes). Biochemical studies for the screening of these inborn errors of metabolism were normal except for sialotransferrin isoelectric focusing, which showed a type 2 pattern. However, 16 days later, together with the remission of the meningitis process, the sialotransferrin pattern had normalized. The apolipoprotein C-III (an O-glycoprotein) profile was normal in all samples analysed. In conclusion, infectious events should be ruled out in the differential diagnosis of CDG syndromes. Furthermore, our findings highlight the possibility that the type 2 IEF pattern of serum sialotransferrin detected in some patients with neonatal death due to organ failure and septic events might be secondary to the infectious process.

Mutational spectrum of classical galactosaemia in Spain and Portugal.

Classical galactosaemia is an autosomal recessive inherited metabolic disorder due to deficient galactose-1-phosphate uridyltransferase (GALT). Over 180 different base changes and disease-causing mutations have been reported in the GALT gene. Mutation p.Q188R was found to be the most common molecular defect among caucasian classical galactosaemia patients. We have characterized the spectrum of GALT mutations in a group of 51 Spanish families and 32 Portuguese families with this disease. p.Q188R is also the most prevalent mutation in the Spanish and Portuguese population, accounting for 50% and 57.8% of galactosaemic alleles, respectively. An additional 15 mutations were also identified in Spanish patients, four of which were novel: p.D28H, p.S181A, c.658dupG and c.377+53_1059+87del. In the Portuguese population, 11 different mutations were found, three of which were novel: p.R33H, p.P185S, and p.S192G. The differences observed between the genotypes identified in Portuguese and Spanish galactosaemic populations are notable. Only mutations p.Q188R, p.R148Q and c.820+13g>a were identified in both populations. In spite of the geographical proximity of Spain and Portugal, it seems that they have received genetic influences from different populations. The repeated migrations that occurred in the Iberian Peninsula throughout centuries may explain such variability.

[Treatment response to lamivudine in chronic hepatitis B patients]. / Respuesta al tratamiento con lamivudina en pacientes con hepatitis crónica por virus B.

OBJECTIVE: The main objective was to find a biochemistry and virology response in positive and negative HBeAg patients who had been treating with lamivudine. Furthermore, the secondary objective was to make a description about kidney function changes that could be found in patients under treatment with lamivudine. METHOD: Thirty patients with chronic B hepatitis under treatment with lamivudine had been retrospectively studied since November 1999 to March 2004, in a Digestive Unit, in Ciudad Real Hospital. RESULTS: Twenty nine out of 30 patients were included, 8 out of 29 were positive HBeAg, and 21 out of 29 were negative HBeAg. Seven patients had been treated with IFN. Thus, 8 patients had been in need of adefovir treatment after lamivudine trial. The average of treatment had been 23.7 months (3 months-46 months). In fact, none of them were changed from positive HBsAg to negative HBsAg. Nevertheless, we have observed those results after lamivudine treatment. Firstly, 50% positive HBe Ag patients have carried on negative DNA results. Although 25% positive HBe Ag patients had converted to negative HBe Ag. But they did not show any anti HBe. Secondly, 76% negative HBe Ag patients had been suffering a DNA decreased, even though some of them had had a negative DNA results. Thirdly, we found some lamivudine mutation (50% in positive HBe Ag patients and 19% in negative HBe Ag patients). Finally, all the patients with negative DNA had maintained a normal AST and ALT levels. Thus, function renal had been normal under lamivudine trial. CONCLUSION: According to several authors, the response to lamivudine treatment had been adequate in our population. Nevertheless, our study have shown that antiHBe levels had not been suffering any change during lamivudine treatment. In addition, we have found a smaller figures (19%) of lamivudine mutations in negative HBe Ag patients than other studies (25% in patients who were followed up for 1 year).