Efficacy and safety of secukinumab for the treatment of severe ABCA12 deficiency-related ichthyosis in a child.

Background: Patients with severe autosomal recessive congenital ichthyosis (ARCI) show a T helper 17/interleukin 17 (Th17/IL17) skewing in their skin and serum, resembling the inflammatory profile of psoriatic patients. Secukinumab, an IL-17A inhibitor, has shown clinical efficacy in patients with moderate-to-severe plaque psoriasis. Aims: To test the clinical efficacy and safety of secukinumab in a paediatric patient with ATP-binding cassette subfamily A member 12 deficiency-related severe erythrodermic ARCI. Materials & Methods: 6-months therapeutic trial. During the first 4-weeks induction period, the patient received weekly subcutaneous injections of 150 mg secukinumab (five injections in total). During the following 20-weeks maintenance period, the patient was given a subcutaneous injection of 150 mg secukinumab every 4 weeks. Result & Discussion: After the 6-months therapy period, there was a 48% reduction from the baseline Ichthyosis-Area-Severity-Index (-Erythema/-Scaling) score. The treatment was well tolerated. Moreover, cytokine analysis revealed a reduction of keratinocyte-derived proinflammatory cytokines and an abrogation of Th17-skewing during therapy. Conclusion: Further studies are needed to evaluate the effects of the use of IL-17A inhibition in ARCI patients.

The uncalibrated prothrombinase-induced clotting time test. Equally convenient but more precise than the aPTT for monitoring of unfractionated heparin.

The activated partial thromboplastin time test (aPTT) represents one of the most commonly used diagnostic tools in order to monitor patients undergoing heparin therapy. Expression of aPTT coagulation time in seconds represents common practice in order to evaluate the integrity of the coagulation cascade. The prolongation of the aPTT thus can indicate whether or not the heparin level is likely to be within therapeutic range. Unfortunately aPTT results are highly variable depending on patient properties, manufacturer, different reagents and instruments among others but most importantly aPTT's dose response curve to heparin often lacks linearity. Furthermore, aPTT assays are insensitive to drugs such as, for example, low molecular weight heparin (LMWH) and direct factor Xa (FXa) inhibitors among others. On the other hand, the protrombinase-induced clotting time assay (PiCT®) has been show to be a reliable functional assay sensitive to all heparinoids as well as direct thrombin inhibitors (DTIs). So far, the commercially available PiCT assay (Pefakit®PiCT®, DSM Nutritional Products Ltd. Branch Pentapharm, Basel, Switzerland) is designed to express results in terms of units with the help of specific calibrators, while aPTT results are most commonly expressed as coagulation time in seconds. In this report, we describe the results of a pilot study indicating that the Pefakit PiCT UC assay is superior to the aPTT for the efficient monitoring of patients undergoing UFH therapy; it is also suitable to determine and quantitate the effect of LMWH therapy. This indicates a distinct benefit when using this new approach over the use of aPPT for heparin monitoring.

The natural history of classic galactosemia: lessons from the GalNet registry.

BACKGROUND: Classic galactosemia is a rare inborn error of carbohydrate metabolism, caused by a severe deficiency of the enzyme galactose-1-phosphate uridylyltransferase (GALT). A galactose-restricted diet has proven to be very effective to treat the neonatal life-threatening manifestations and has been the cornerstone of treatment for this severe disease. However, burdensome complications occur despite a lifelong diet. For rare diseases, a patient disease specific registry is fundamental to monitor the lifespan pathology and to evaluate the safety and efficacy of potential therapies. In 2014, the international Galactosemias Network (GalNet) developed a web-based patient registry for this disease, the GalNet Registry. The aim was to delineate the natural history of classic galactosemia based on a large dataset of patients. METHODS: Observational data derived from 15 countries and 32 centers including 509 patients were acquired between December 2014 and July 2018. RESULTS: Most affected patients experienced neonatal manifestations (79.8%) and despite following a diet developed brain impairments (85.0%), primary ovarian insufficiency (79.7%) and a diminished bone mineral density (26.5%). Newborn screening, age at onset of dietary treatment, strictness of the galactose-restricted diet, p.Gln188Arg mutation and GALT enzyme activity influenced the clinical picture. Detection by newborn screening and commencement of diet in the first week of life were associated with a more favorable outcome. A homozygous p.Gln188Arg mutation, GALT enzyme activity of ≤ 1% and strict galactose restriction were associated with a less favorable outcome. CONCLUSION: This study describes the natural history of classic galactosemia based on the hitherto largest data set.

Relationships between neuronal death and the cellular redox status. Focus on the developing nervous system.

During the development of the nervous system, a large number of neurons are eliminated through naturally occurring neuronal death. Many morphological and biochemical properties of such dying neurons are reminiscent of apoptosis, a type of death involving the action of genetically-programmed events but also epigenetic phenomena including oxidative stress. The following review contains three parts focusing respectively on basic knowledge of neuronal death and redox regulation, the mechanisms involved in neuronal death which are ordered in three sequential phases, and on the complex relations between neuronal fate and the redox status. Finally, we point out that oxidants are not always detrimental for neuronal survival. On the one hand, dying neurons often display signs of oxidative stress, including an elevation of their intracellular concentration of free radicals. Antioxidants may reduce the extent of neuronal death, suggesting a causal implication of free radicals in the death-process. On the other hand, at high concentrations antioxidants may lose their protective effects on developing neurons, and a non-lethal oxidative stress may potentiate the protective effects of other agents. These data suggest that free radicals, perhaps through their effects on cellular signalling pathways, may have positive effects on neuronal survival, provided that their intraneuronal concentrations are maintained at low levels. Much evidence suggests that the neuronal redox status must be maintained within a narrow range of values compatible with survival. Antioxidants may protect neurons subjected to an oxidative stress following axotomy or trophic factor-deprivation; but excessive reduction may become equally detrimental for neurons.

Synthesis of a mammalian parvovirus in Brij-58-lysed cells.

An in vitro system was developed, prepared by lysis of parvovirus LuIII-infected cells with Brij-58. In this subcellular system, DNA of viral genome size and synthesized and subsequently packaged into particles with physicochemical properties of mature LuIII virions.

Multiplication of parvovirus LuIII in a synchronized culture system. III. Replication of viral DNA.

The replication of the single-stranded DNA (ssDNA) of parvovirus LuIII was studied in synchronized HeLa cells. After infection of the cells in early S phase, synthesis of a replicative form (RF) DNA became detectable as early as 9 h postinfection, i.e., after display of the cellular helper function(s) indispensable for the replication of LuIII virus. According to digestion with nuclease S1, hybridization studies, and electron microscopy, RF DNA is a linear, double-stranded molecule comparable in length to mature ssDNA. It sedimented around 15S in neutral solution and banded at 1.714 g/ml in CsCl. Moreover, replication of LuIII DNA obviously includes a further replicative intermediate DNA which sedimented in front of RF DNA and bore single-stranded side-chains. Newly synthesized DNA disappeared from pools containing both RF DNA and replicative intermediate DNA within 5 min and reappeared in progeny virions only after 15 min. Intranuclear accumulation of significant amounts of progeny ssDNA could not be detected. It was postulated, therefore, that newly synthesized ssDNA is immediately enclosed in a stable maturation complex and resists extraction by the method of Hirt (1967).

Multiplication of parvovirus LuIII in a synchronized culture system. IV. Association of viral structural polypeptides with the host cell chromatin.

Newly synthesized structural polypeptides of parvovirus LuIII, VP1 (62,000 daltons) and VP2 (74,000 daltons), were detected in nuclei of synchronized, infected HeLa cells at 11 to 12 h postinfection, i.e., after cells had passed through the S phase of the cell cycle. At this time, most of intranuclear viral polypeptides were associated with the chromatin acidic proteins. However, 13 to 14 h postinfection, about one-third of intranuclear VP1 and VP2 also could be extracted in the fraction containing nuclear sap proteins. According to pulse-chase experiments, VP1 and VP2 accumulated in the chromatin with a time lag of 20 to 30 min. About 90% of these chromatin-associated viral polypeptides represented empty viral capsids. In addition, chromatin prepared at 14 h postinfection contained 90 to 95% of the total intranuclear viral 16S replicative-form DNA. Since viral replicative-form DNA and empty viral capsids seem to be associated specifically with cellular chromatin, we assume that this subnuclear structure is the site of the synthesis of progeny viral DNA and the formation of complete virions.

Nascent-polypeptide-associated complex.

Nascent-polypeptide-associated complex (NAC) is a heterodimeric complex which can reversibly bind to eukaryotic ribosomes. NAC is located in direct proximity to newly synthesized polypeptide chains as they emerge from the ribosome. Although its function is thought to be conserved from yeast to humans our current knowledge about what NAC actually does in a living cell is incomplete. It has been suggested that NAC is a (i) dynamic component of the ribosomal exit tunnel, providing a shield for nascent polypeptides, (ii) negative regulator of translocation into the endoplasmic reticulum and (iii) positive regulator of translocation into the mitochondria. However, none of these hypotheses is generally accepted. Moreover, the individual subunits of NAC have been implicated in processes related to transcription rather than translation, and it is currently under debate whether NAC might be a protein of dual function. This review attempts to summarize the data from different fields and to discuss the partly controversial results in a common context.

RAC, a stable ribosome-associated complex in yeast formed by the DnaK-DnaJ homologs Ssz1p and zuotin.

The yeast cytosol contains multiple homologs of the DnaK and DnaJ chaperone family. Our current understanding of which homologs functionally interact is incomplete. Zuotin is a DnaJ homolog bound to the yeast ribosome. We have now identified the DnaK homolog Ssz1p/Pdr13p as zuotin's partner chaperone. Zuotin and Ssz1p form a ribosome-associated complex (RAC) that is bound to the ribosome via the zuotin subunit. RAC is unique among the eukaryotic DnaK-DnaJ systems, as the 1:1 complex is stable, even in the presence of ATP or ADP. In vitro, RAC stimulates the translocation of a ribosome-bound mitochondrial precursor protein into mitochondria, providing evidence for its chaperone-like effect on nascent chains. In agreement with the existence of a functional complex, deletion of each RAC subunit resulted in a similar phenotype in vivo. However, overexpression of zuotin partly rescued the growth defect of the Delta ssz1 strain, whereas overexpression of Ssz1p did not affect the Delta zuo1 strain, suggesting a pivotal function for the DnaJ homolog.