Efficacy and safety of cyclic pyranopterin monophosphate substitution in severe molybdenum cofactor deficiency type A: a prospective cohort study

BACKGROUND

Molybdenum cofactor deficiency (MoCD) is characterised by early, rapidly progressive postnatal encephalopathy and intractable seizures, leading to severe disability and early death. Previous treatment attempts have been unsuccessful. After a pioneering single treatment we now report the outcome of the complete first cohort of patients receiving substitution treatment with cyclic pyranopterin monophosphate (cPMP), a biosynthetic precursor of the cofactor.

METHODS

In this observational prospective cohort study, newborn babies with clinical and biochemical evidence of MoCD were admitted to a compassionate-use programme at the request of their treating physicians. Intravenous cPMP (80-320 μg/kg per day) was started in neonates diagnosed with MoCD (type A and type B) following a standardised protocol. We prospectively monitored safety and efficacy in all patients exposed to cPMP.

FINDINGS

Between June 6, 2008, and Jan 9, 2013, intravenous cPMP was started in 16 neonates diagnosed with MoCD (11 type A and five type B) and continued in eight type A patients for up to 5 years. We observed no drug-related serious adverse events after more than 6000 doses. The disease biomarkers urinary S-sulphocysteine, xanthine, and urate returned to almost normal concentrations in all type A patients within 2 days, and remained normal for up to 5 years on continued cPMP substitution. Eight patients with type A disease rapidly improved under treatment and convulsions were either completely suppressed or substantially reduced. Three patients treated early remain seizure free and show near-normal long-term development. We detected no biochemical or clinical response in patients with type B disease.

INTERPRETATION

cPMP substitution is the first effective therapy for patients with MoCD type A and has a favourable safety profile. Restoration of molybdenum cofactor-dependent enzyme activities results in a greatly improved neurodevelopmental outcome when started sufficiently early. The possibility of MoCD type A needs to be urgently explored in every encephalopathic neonate to avoid any delay in appropriate cPMP substitution, and to maximise treatment benefit.

FUNDING

German Ministry of Education and Research; Orphatec/Colbourne Pharmaceuticals.

[Integration of hospital social services in the rehabilitation of accident patients by the statutory accident insurance. Results of a one-year model project]

In accident patient care, there is a substantial overlap between the scope of duties of hospital social services and tasks fulfilled by the German statutory accident insurances' visiting staff that regularly takes care of accident patients. Therefore, a project on the integration of hospital social services into the organizational structures of the German statutory accident insurance was initiated which aimed at optimising communication and realising synergy effects. A formative evaluation of the project was conducted that provided process- and outcome-related data for a comprehensive evaluation of the strengths and potentials of the project. Report forms containing patient-related information were completed by hospital social services. Forms were evaluated in terms of their utility for case management by accident insurance administrators using a checklist. Project implementation and procedures were documented and evaluated using semi-structured interviews with social services staff and accident insurance employees. Through the model, a comprehensive care for accident patients could be reached. In one third of all cases reviewed, rehabilitation management could be improved by including hospital social services. Moreover, in one third of all cases, care-related activities initiated by accident insurance funds could be reduced by involving local hospital social services. The report form used by hospital social services was evaluated as a useful tool in the context of patient care and rehabilitation management. The model was evaluated by interview participants as a highly targeted approach in accident patients' care management. Implications of the study for improving health care are discussed.

Equations of state for POPX lipids at the air/water interface. A comprehensive study

We have investigated monomolecular fluid-like films of palmitoyl oleoylphosphatidyl lipids with choline, glycerol and serine head groups, respectively. Conventional Langmuir trough experiments have been evaluated towards a thermodynamic analysis applying a novel approach that was recently developed in this laboratory. Our work involves elaborate efforts to exclude possible error sources of the basic measuring parameters. By means of pertinent mass conservation plots it could then be shown that the present lipids form a practically insoluble monolayer. Relative deviations of the lateral pressure from its ideal (gaseous) value are seen to be a very pronounced linear function of the surface concentration (between 1 and about 35 mN/m). They reveal a clearly manifested Boyle point around 4 mN/m, indicating formation of aggregates in the very low pressure range. The results are discussed in terms of a rather simple quantitative formulation of the underlying equation of state including fit curves of the related partial molecular area and Gibbs free energy.

Nmi protein interacts with regions that differ between MycN and Myc and is localized in the cytoplasm of neuroblastoma cells in contrast to nuclear MycN

Myc family proteins play an important role in cellular processes such as proliferation, differentiation, apoptosis and transformation. A number of interaction partners of Myc have been identified, such as Max, p107, TBP, YY1, Miz-1, AP-2 and Nmi. Both Max and Nmi also bind to MycN. In contrast to the well defined binding of Max to Myc family proteins the interaction of Nmi with Myc or MycN is only poorly characterized. By employing the yeast two-hybrid system we have mapped the regions of MycN and Myc responsible for binding to Nmi. For MycN exclusively a central region mediates binding to Nmi. In contrast, for Myc a C-terminal portion of the protein, and possibly also a central part, is involved in Nmi interaction. Nmi does not interact with Max and has no transactivation capabilities in yeast, suggesting that Nmi alone is not a transcriptional activator in mammalian cells. Immunofluorescence demonstrates that both in 293 embryonic kidney cells and in Kelly neuroblastoma cells all detectable ectopically expressed Nmi is localized in the cytoplasm, in part in a punctate, granular pattern. MycN, which is highly expressed in Kelly cells consequent to amplification, appears to be localized exclusively in the nuclei. This directly demonstrates that in the same cell at least the major proportion of MycN and Nmi is localized in different cellular compartments. This result is confirmed by the finding that endogenous Nmi, which is expressed in Kelly cells only after stimulation with interferon gamma, is detected exclusively in the cytoplasm of these cells. Therefore only a very small amount of MycN and Nmi is likely to be involved in MycN/Nmi interaction in vivo.

Translocation breakpoint maps 5 kb 3' from TWIST in a patient affected with Saethre-Chotzen syndrome

Saethre-Chotzen syndrome, a common autosomal dominant craniosynostosis in humans, is characterized by brachydactyly, soft tissue syndactyly and facial dysmorphism including ptosis, facial asymmetry, and prominent ear crura. Previously, we identified a yeast artificial chromosome that encompassed the breakpoint of an apparently balanced t(6;7) (q16.2;p15.3) translocation associated with a mild form of Saethre-Chotzen syndrome. We now describe, at the DNA sequence level, the region on chromosome 7 affected by this translocation event. The rearrangement occurred approximately 5 kb 3' of the human TWIST locus and deleted 518 bp of chromosome 7. The TWIST gene codes for a transcription factor containing a basic helix-loop-helix (b-HLH) motif and has recently been described as a candidate gene for Saethre-Chotzen syndrome, based on the detection of mutations within the coding region. Potential exon sequences flanking the chromosome 7 translocation breakpoint did not hit known genes in database searches. The chromosome rearrangement downstream of TWIST is compatible with the notion that this is a Saethre-Chotzen syndrome gene and implies loss of function of one allele by a positional effect as a possible mechanism of mutation to evoke the syndrome.

Preferential partitioning of melittin into the air/water interface: structural and thermodynamic implications

The membrane active agent melittin has been investigated with regard to the formation of a Langmuir monolayer and the accordingly induced surface activities. We show that in spite of its considerable solubility in an aqueous medium, this peptide nevertheless largely accumulates in the air/water interface unless the lateral pressure is raised beyond a certain threshold value depending on the pH in the subphase. The true surface concentrations have been determined by means of a recently developed novel method based on thermodynamic principles. It affords an access to the partitioning equilibrium between the surface and subphase domains, provided the latter surrounding is not excessively preferred. In the present case this approach was used to derive quantitative information on the pertinent interfacial structure and thermodynamics. In particular, the apparent molecular area and the Gibbs energy of mutual interaction in the monolayer could be evaluated as a function of the applied surface pressure. The data suggest the existence of two structural conversions in the course of an increasing lateral compression. The surface-associated peptide accordingly assumes three different states of successively reduced area requirements, supposedly owing to an orientational transition involving a straightening up of a helical conformation. This conclusion is corroborated by surface potential measurements reflecting corresponding changes of the effective dipole moment perpendicular to the surface.