Methylmalonic acidemia resulting from genetic deficiency of methylmalonyl CoA mutase (MCM) is an often fatal metabolic disease. Somatic gene therapy for this disorder may require gene replacement in the liver. We describe overexpression of MCM in the liver of mice after in vivo gene delivery using asialoglycoprotein/polylysine/DNA (ASO/PL/DNA) targeted delivery to the liver of plasmids expressing recombinant MCM. After intravenous administration of the ASO/PL/DNA complex, the vector sequences are cleared from the blood with t1/2 = 2.5 min and > 95% of the vector is taken up by the liver. Vector sequences are cleared from the liver with t1/2 = 1.0-1.3 hr. MCM enzyme activity in the liver increases to levels 30-40% over baseline 6-24 hr after injection. No acute or chronic toxicity was observed. This net level of expression is likely to be therapeutic for MCM if the complex could be administered repetitively to treat acute episodes of life-threatening acidosis or establish a steady-state level of MCM activity. Repetitive administration of the ASO/PL/DNA complexes in mice was associated with formation of antibodies against asialo-orosomucoid and the asialo-orosomucoid complex but not against DNA.

We have developed a new technique which makes silver intensification ofthe oxidatively polymerized diaminobenzidine (DAB), the endproduct of peroxidase reaction, less laborious without any loss in selectivity or sensitivity. The new technique is based on two strategies: (a) increasing the argyrophilia of the DAB by modifying its polymerization with Ni ions, and (b) decreasing tissue argyrophila by using a mildly acidic physical developer

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Objectives: In the current prospective study our aim was to analyse the distribution of the factor V Leiden (G1691A) mutation in preterm and full-term neonates with grade I intraventricular haemorrhage and in control neonates. Study Method: A group of 125 individually selected neonates with grade I intraventricular haemorrhage and 128 controls were investigated. Results: The allele frequency was 7.2% in the total population of affected infants while it was 3.9% in the controls (p < 0.05); the latter corresponds to an average European allele frequency in healthy populations. When the infants were grouped as premature (<2,500 g and ≤36 weeks of gestational age) and appropriate for gestational age full-term infants the statistical analysis revealed an increased prevalence of the mutation in the premature group (10% allele frequency vs. 4.8% in the controls, p < 0.05), and a normal prevalence in the mature group (4.6 vs. 3.1%, respectively); therefore, the overall increase was due to the increase of incidence rate in preterm neonates. Conclusions: These data confirm our previous results and suggest that as the preterm and term infants differ from each other in haemorrhage susceptibility in many clinical particulars, carrying of the mutation has probably also a different impact in premature and in full-term infants with respect to the intraventricular haemorrhage.

The prevalence of the Leiden mutation was tested in 50 mothers of premature infants and in 56 mothers of intrauterine-growth-retarded neonates. The prevalence of the Leiden mutation was 7.2% in the mothers of growth-retarded neonates and 18% in the group of mothers of premature infants, the latter being significantly higher than the 6.3% prevalence of this mutation in healthy Hungarian subjects (p < 0.01). In spite of the relatively small number of mothers examined, the unexpected finding may call attention to a hitherto unknown relationship.