Variable phenotypes and outcomes associated with the MMACHC c.482G > A mutation: follow-up in a large CblC disease cohort.

BACKGROUND: The aim of this study was to characterize the variable phenotypes and outcomes associated with the methylmalonic aciduria and homocystinuria type C protein gene (MMACHC) c.482G > A mutation in 195 Chinese cases with CblC disease. METHODS: We carried out a national, retrospective multicenter study of 195 Chinese patients with CblC disease attributable to the MMACHC c.482G > A variant either in a homozygous or compound heterozygous state. The control group consisted of 200 patients diagnosed with CblC disease who did not possess the c.482G > A mutation. Clinical features, including disease onset, symptoms, biochemical metabolites, gene mutation, and follow-up outcomes were reviewed and analyzed in detail. The median follow-up period spanned 3 years and 8 months, with a range of 1 year and 2 months to 12 years and 10 months. RESULTS: Among 195 patients carrying the c.482G > A variant, 125 (64.1%) cases were diagnosed by newborn screening (NBS), 60 (30.8%) cases were detected due to disease onset, and 10 (5.1%) cases were identified from sibling diagnoses. One hundred and seventeen (93.6%) individuals who were diagnosed by NBS, and nine patients who came from sibling diagnoses remained asymptomatic in this study. From 69 symptomatic patients of the c.482G > A group, more patients presented with later onset, and the top six common clinical symptoms at disease onset were developmental delay (59.4%), lower limb weakness and poor exercise tolerance (50.7%), cognitive decline (37.7%), gait instability and abnormal posture (36.2%), seizures (26.1%), and psychiatric and behavioral disturbances (24.6%). In the 159 symptomatic patients lacking c.482G > A variants, the most frequently observed clinical manifestations at disease onset included developmental delay (81.8%), lethargy and feeding difficulty (62.9%), lower limb weakness and poor exercise tolerance (54.7%), prolonged neonatal jaundice (51.6%), vomiting (47.2%), and seizures (32.7%). Before treatment, the levels of blood propionylcarnitine, propionylcarnitine/acetylcarnitine ratio, and homocysteine in the c.482G > A group were significantly lower (P < 0.05) than those in the non-c.482G > A group, while the concentration of urinary methylmalonic acid was slightly lower (P > 0.05). The degree of decline in the above metabolites after treatment in different groups significantly differed in both plasma total homocysteine values and urinary methylmalonic acid levels (P < 0.05). In patients carrying the c.482G > A variant compared with the non-c.428G > A group, there were markedly lower rates of mortality (0.5% vs. 2.0%) and developmental delay (20.5% vs. 65.5%). When compared with individuals diagnosed due to disease onset, those identified through NBS in either group exhibited a reduced proportion of disease onset (6.7% vs. 100% in the c.482G > A group, 54.4% vs. 100% in the non-c.482G > A group), lower mortality (0.0% vs. 1.7% in the c.482G > A group, 0.0% vs. 3.6% in the non-c.482G > A group), and had a higher percentage of patients exhibiting normal psychomotor and language development (99.3% vs. 33.3% in the c.482G > A group, 58.9% vs. 10.9% in the non-c.482G > A group). CONCLUSIONS: The c.482G > A variant in MMACHC is associated with late-onset and milder phenotypes of CblC disease. Patients with this mutation tend to have a relatively better response to hydroxocobalamin, better metabolic control, and more favorable neurological outcomes. NBS and other appropriate pre-symptomatic treatments seem to be helpful in early diagnosis, resulting in favorable clinical outcomes. Video Abstract (MP4 136794 kb).

[Effects of cPKCßII/γ membrane translocation ischemic/hypoxic tolerance induced by morphine postconditioning in hippocampal slices].

OBJECTIVE: To determine whether or not morphine postconditioning can induce ischemic/hypoxic tolerance in neurons subjected to reperfusion injury after oxygen-glucose deprivation (OGD). METHODS: Hippocampal slices of 400 µm thickness were prepared from healthy adult male BALB/c mice. The slices were incubated in oxygen-saturated ACSF without or with calcium, then were subjected to OGD for 20 min. After recovery, the samples were immersed in oxygenated artificial fluid for 2 hours in the presence or absence of morphine postconditioning at 3 µmol/L during the first 5 - 60 min. The assessment of slices injury was performed by a determination of the intensity of slice stain incubated with TTC (2% 2, 3, 5-triphenyltetrazolium chloride) and the leakage rate of LDH also evaluated. At the designated periods during incubation, some slices were immersed into liquid nitrogen for a later analysis of Western blot. The frozen slices were homogenized, sonicated and centrifuged to separate soluble and particulate proteins. 10% SDS-PAGE Western blot was used to identify the changes of membrane-specific translocation of cPKCßII/γ. RESULTS: After reperfusion, the cell survival significantly decreased with the elongation of OGD (51.4%). The release rate of LDH (184.05%) significantly increased simultaneously. In hippocampal slices postconditioned with morphine for 20 - 60 min, the release rate of LDH (136%, 142%, 144%) significantly decreased as compared with the group OGD. In the hippocampal slices postconditioned with morphine for 10 - 30 min, the cell survival rate (64.9%, 69.9%, 63.5%) significantly increased as compared with reperfusion alone. cPKCγ of particulate fraction increased versus the control. And there was a corresponding decrease of cytosolic fraction. Morphine postconditioning significantly inhibited the cPKCγ isoform-specific membrane translocation. It declined from 136% in the group OGD to 123%, 118%, 114% in the group morphine 20 - 60 min. cPKCßII membrane translocation had no change. CONCLUSION: Morphine postconditioning can induce ischemic tolerance in nerons. The protective mechanism may be through inhibiting the cPKCγ isoform-specific membrane translocation.

Quantification of multi-residue levels in peach juices, pulps and peels using dispersive liquid-liquid microextraction based on floating organic droplet coupled with gas chromatography-electron capture detection.

In this paper, polychlorinated biphenyl (PCB), organochlorine pesticide (OCP) and pyrethroid pesticides in peach was investigated by comparing their residual level in peach juice, pulps and peels using dispersive liquid-liquid microextraction based on solidification of floating organic droplet (DLLME-SFO) combined with gas chromatography-electron capture detection (GC-ECD). Extraction conditions such as the type of extractant, volume of extractant and dispersant, salt effect and extraction time were optimized. For juice samples, the linearity of the method was obtained in the range of 10-2000 ng L(-1),with determination coefficients>0.99. The limits of detection (LOD) of the method were ranged between 2.8 and 18.5 ng L(-1). For pulp and peel samples, the developed method is linear over the range assayed, 1-20 µg kg(-1),with coefficients also >0.99. The relative recoveries of compounds analyzed from juice, pulp and peel samples were in the range of 73-106% with a relative standard deviation between 2.6 and 11.8%. The proposed method was applied to the simultaneous analysis of residues in real peach juice, pulp and peel samples. As a result, there were no target analytes found in peach juices and pulps while 3.3 µg kg(-1) cyhalothrin and 3.5 µg kg(-1) fenvalerate were found in peels. The experiment results revealed that the pyrethroid residues just deposited on the peels of the fruits, but did not move into pulps and juices.