Mutations in ATP1A1 Cause Dominant Charcot-Marie-Tooth Type 2

Although mutations in more than 90 genes are known to cause CMT, the underlying genetic cause of CMT remains unknown in more than 50% of affected individuals. The discovery of additional genes that harbor CMT2-causing mutations increasingly depends on sharing sequence data on a global level. In this way-by combining data from seven countries on four continents-we were able to define mutations in ATP1A1, which encodes the alpha1 subunit of the Na⁺,K⁺-ATPase, as a cause of autosomal-dominant CMT2. Seven missense changes were identified that segregated within individual pedigrees: c.143T>G (p.Leu48Arg), c.1775T>C (p.Ile592Thr), c.1789G>A (p.Ala597Thr), c.1801_1802delinsTT (p.Asp601Phe), c.1798C>G (p.Pro600Ala), c.1798C>A (p.Pro600Thr), and c.2432A>C (p.Asp811Ala). Immunostaining peripheral nerve axons localized ATP1A1 to the axolemma of myelinated sensory and motor axons and to Schmidt-Lanterman incisures of myelin sheaths. Two-electrode voltage clamp measurements on Xenopus oocytes demonstrated significant reduction in Na⁺ current activity in some, but not all, ouabain-insensitive ATP1A1 mutants, suggesting a loss-of-function defect of the Na⁺,K⁺ pump. Five mutants fall into a remarkably narrow motif within the helical linker region that couples the nucleotide-binding and phosphorylation domains. These findings identify a CMT pathway and a potential target for therapy development in degenerative diseases of peripheral nerve axons.

Recyclable Magnetic Titania Nanocomposite from Ilmenite with Enhanced Photocatalytic Activity

Using ilmenite as a raw material, iron was converted into Fe₃O₄ magnetic fluid, which further was combined with titanium filtrate by a solvothermal method. Finally Fe₃O₄/TiO₂ nanocomposites with the uniform size of 100-200 nm were prepared. This approach uses rich, inexpensive ilmenite as a titanium and iron source, which effectively reduces the production cost. The crystal structure, chemical properties and morphologies of the products were characterized by SEM, TEM, XRD, FTIR, BET, UV-Vis, XPS and VSM. The novel photocatalyst composed of face-centered cubic Fe₃O₄ and body-centered tetragonal anatase-TiO₂ exhibits a spherical shape with porous structures, superparamagnetic behavior and strong absorption in the visible light range. Using the degradation reaction of Rhodamine B (RhB) to evaluate the photocatalytic performance, the results suggest that Fe₃O₄/TiO₂ nanocomposites exhibit excellent photocatalytic activities and stability under visible light and solar light. Moreover, the magnetic titania nanocomposites displayed good magnetic response and were recoverable over several cycles. Based on the trapping experiments, the main active species in the photocatalytic reaction were confirmed and the possible photocatalytic mechanism of RhB with magnetic titania was proposed. The enhanced photocatalytic activity and stability, combined with excellent magnetic recoverability, make the prepared nanocomposite a potential candidate in wastewater purification.

Recent advances in rapid and nondestructive determination of fat content and fatty acids composition of muscle foods

Conventional methods for determining fat content and fatty acids (FAs) composition are generally based on the solvent extraction and gas chromatography techniques, respectively, which are time consuming, laborious, destructive to samples and require use of hazard solvents. These disadvantages make them impossible for large-scale detection or being applied to the production line of meat factories. In this context, the great necessity of developing rapid and nondestructive techniques for fat and FAs analyses has been highlighted. Measurement techniques based on near-infrared spectroscopy, Raman spectroscopy, nuclear magnetic resonance and hyperspectral imaging have provided interesting and promising results for fat and FAs prediction in varieties of foods. Thus, the goal of this article is to give an overview of the current research progress in application of the four important techniques for fat and FAs analyses of muscle foods, which consist of pork, beef, lamb, chicken meat, fish and fish oil. The measurement techniques are described in terms of their working principles, features, and application advantages. Research advances for these techniques for specific food are summarized in detail and the factors influencing their modeling results are discussed. Perspectives on the current situation, future trends and challenges associated with the measurement techniques are also discussed.

Safety and efficacy evaluation of laparoscopy in colorectal cancer with liver metastasis

OBJECTIVE

To study the safety and efficacy of simultaneous completion of colorectal cancer resection and liver metastasis resection by total laparoscopy.

PATIENTS AND METHODS

In the observation group, 40 patients with colorectal cancer combined with liver metastasis (CRCLM) were selected to receive total laparoscopic surgery. At the same time, 40 cases were selected for laparoscopic resection of colorectal cancer and hepatic resection as control group.

RESULTS

The outcomes of the two methods in the treatment of CRCLM were compared. The results showed that the difference in surgery time between the two groups was not statistically significant (p>0.05). The blood loss, drainage tube retention time and anal exhaust recovery time in the observation group were significantly less than those in control group (p<0.05). No significant difference in completion rate was found between the two groups (p>0.05); the prevalence rate of complications in the observation group was significantly lower than that in control group (p<0.05). No significant differences in the median survival period and the survival rate at 1 year, 2 years and 3 years after surgery were found between the two groups (p>0.05).

CONCLUSIONS

The outcomes of total laparoscopy in the treatment of CRCLM are not inferior to open surgery.

Hypomorphic mutations in POLR3A are a frequent cause of sporadic and recessive spastic ataxia

Despite extensive efforts, half of patients with rare movement disorders such as hereditary spastic paraplegias and cerebellar ataxias remain genetically unexplained, implicating novel genes and unrecognized mutations in known genes. Non-coding DNA variants are suspected to account for a substantial part of undiscovered causes of rare diseases. Here we identified mutations located deep in introns of POLR3A to be a frequent cause of hereditary spastic paraplegia and cerebellar ataxia. First, whole-exome sequencing findings in a recessive spastic ataxia family turned our attention to intronic variants in POLR3A, a gene previously associated with hypomyelinating leukodystrophy type 7. Next, we screened a cohort of hereditary spastic paraplegia and cerebellar ataxia cases (n = 618) for mutations in POLR3A and identified compound heterozygous POLR3A mutations in ∼3.1% of index cases. Interestingly, >80% of POLR3A mutation carriers presented the same deep-intronic mutation (c.1909+22G>A), which activates a cryptic splice site in a tissue and stage of development-specific manner and leads to a novel distinct and uniform phenotype. The phenotype is characterized by adolescent-onset progressive spastic ataxia with frequent occurrence of tremor, involvement of the central sensory tracts and dental problems (hypodontia, early onset of severe and aggressive periodontal disease). Instead of the typical hypomyelination magnetic resonance imaging pattern associated with classical POLR3A mutations, cases carrying c.1909+22G>A demonstrated hyperintensities along the superior cerebellar peduncles. These hyperintensities may represent the structural correlate to the cerebellar symptoms observed in these patients. The associated c.1909+22G>A variant was significantly enriched in 1139 cases with spastic ataxia-related phenotypes as compared to unrelated neurological and non-neurological phenotypes and healthy controls (P = 1.3 × 10-4). In this study we demonstrate that (i) autosomal-recessive mutations in POLR3A are a frequent cause of hereditary spastic ataxias, accounting for about 3% of hitherto genetically unclassified autosomal recessive and sporadic cases; and (ii) hypomyelination is frequently absent in POLR3A-related syndromes, especially when intronic mutations are present, and thus can no longer be considered as the unifying feature of POLR3A disease. Furthermore, our results demonstrate that substantial progress in revealing the causes of Mendelian diseases can be made by exploring the non-coding sequences of the human genome.

Novel mutations in dystonin provide clues to the pathomechanisms of HSAN-VI

OBJECTIVE

To describe a second hereditary sensory autonomic neuropathy type VI (HSAN-VI) family harboring 2 novel heterozygous mutations in the dystonin (DST) gene and to evaluate their effect on neurons derived from induced pluripotent stem cells (iPSC).

METHODS

The family consisted of 3 affected siblings from nonconsanguineous healthy parents. All members underwent clinical and electrophysiologic evaluation and genetic analysis. Two patients underwent quantitative sensory testing (QST), cardiovascular reflexes, dynamic sweat test, and skin biopsy to evaluate somatic and autonomic cutaneous innervation and to get fibroblast cultures for developing iPSC-derived neurons.

RESULTS

Onset occurred in the first decade, with painless and progressive mutilating distal ulcerations leading to amputation and joint deformity. Sensation to pain, touch, and vibration was reduced. Autonomic disturbances included hypohidrosis, pupillary abnormalities, and gastrointestinal and sexual dysfunction. Nerve conduction studies showed a severe axonal sensory neuropathy. QST and autonomic functional studies were abnormal. Skin biopsy revealed a lack of sensory and autonomic nerve fibers. Genetic analysis revealed 2 pathogenic mutations in the DST gene affecting exclusively the DST neuronal isoform-a2. Neurons derived from iPSC showed absence or very low levels of DST protein and short and dystrophic neuritis or no projections at all.

CONCLUSIONS

Unlike the previous HSAN-VI family, our description indicates that DST mutations may be associated with a nonlethal and nonsyndromic phenotype. Neuronal loss affects large and small sensory nerve fibers as well as autonomic ones. Induced-PSC findings suggest that dystonin defect might alter proper development of the peripheral nerves. Dystonin-a2 plays a major role in the HSAN-VI phenotype.

[Assessment and surgical treatment for 58 substernal goiter]

Objective: To investigate the diagnosis and treatment of substernal goiter. Methods: A total of 58 cases with substernal goiters undergoing surgery between January 2005 and December 2015 were analysed retrospectively. There were 10 males and 48 females and their age ranged from 38 to 82 years with a median age of 58 years. According to enhanced CT and clinical signs of substernal goiters, there were 40 cases for typeⅠ, 17 cases for type Ⅱ, and 1 case for type Ⅲ. Results: Patients with typeⅠand Ⅱ substernal goiters (8 cases of papillary carcinoma) underwent low neck and collar-type incision, and patients with type Ⅲ substernal goiters received carotid chest surgery. The use of harmonic scalpel in sternal goiter surgery provided with clearer surgical field, less bleeding. All the operations were successful, and recurrent laryngeal nerve was visually identified in all patients. Postoperative complications included trachyphonia (2 cases), without difficult breathing and tracheal stenosis. Conclusions: Enhanced CT is the best means of preoperatively assessment of substernal goiter. It is feasible to treat patients with typeⅠand Ⅱ substernal goiters by lower neck and collar-type incision. Use of harmonic scalpel in substernal goiter surgery can reduce operation time and bleeding.

Linking genomic reorganization to tumor initiation via the giant cell cycle

To investigate the mechanisms underlying our recent paradoxical finding that mitotically incapacitated and genomically unstable polyploid giant cancer cells (PGCCs) are capable of tumor initiation, we labeled ovarian cancer cells with α-tubulin fused to green fluorescent protein, histone-2B fused to red fluorescent protein and FUCCI (fluorescent ubiquitination cell cycle indicator), and tracked the spatial and time-dependent change in spindle and chromosomal dynamics of PGCCs using live-cell fluorescence time-lapse recording. We found that single-dose (500 nm) treatment with paclitaxel paradoxically initiated endoreplication to form PGCCs after massive cell death. The resulting PGCCs continued self-renewal via endoreplication and further divided by nuclear budding or fragmentation; the small daughter nuclei then acquired cytoplasm, split off from the giant mother cells and acquired competency in mitosis. FUCCI showed that PGCCs divided via truncated endoreplication cell cycle (endocycle or endomitosis). Confocal microscopy showed that PGCCs had pronounced nuclear fragmentation and lacked expression of key mitotic proteins. PGCC-derived daughter cells were capable of long-term proliferation and acquired numerous new genome/chromosome alterations demonstrated by spectral karyotyping. These data prompt us to conceptualize a giant cell cycle composed of four distinct but overlapping phases, initiation, self-renewal, termination and stability. The giant cell cycle may represent a fundamental cellular mechanism to initiate genomic reorganization to generate new tumor-initiating cells in response to chemotherapy-induced stress and contributes to disease relapse.

Rare Variants in MME, Encoding Metalloprotease Neprilysin, Are Linked to Late-Onset Autosomal-Dominant Axonal Polyneuropathies

Axonal polyneuropathies are a frequent cause of progressive disability in the elderly. Common etiologies comprise diabetes mellitus, paraproteinaemia, and inflammatory disorders, but often the underlying causes remain elusive. Late-onset axonal Charcot-Marie-Tooth neuropathy (CMT2) is an autosomal-dominantly inherited condition that manifests in the second half of life and is genetically largely unexplained. We assumed age-dependent penetrance of mutations in a so far unknown gene causing late-onset CMT2. We screened 51 index case subjects with late-onset CMT2 for mutations by whole-exome (WES) and Sanger sequencing and subsequently queried WES repositories for further case subjects carrying mutations in the identified candidate gene. We studied nerve pathology and tissue levels and function of the abnormal protein in order to explore consequences of the mutations. Altogether, we observed heterozygous rare loss-of-function and missense mutations in MME encoding the metalloprotease neprilysin in 19 index case subjects diagnosed with axonal polyneuropathies or neurodegenerative conditions involving the peripheral nervous system. MME mutations segregated in an autosomal-dominant fashion with age-related incomplete penetrance and some affected individuals were isolated case subjects. We also found that MME mutations resulted in strongly decreased tissue availability of neprilysin and impaired enzymatic activity. Although neprilysin is known to degrade β-amyloid, we observed no increased amyloid deposition or increased incidence of dementia in individuals with MME mutations. Detection of MME mutations is expected to increase the diagnostic yield in late-onset polyneuropathies, and it will be tempting to explore whether substances that can elevate neprilysin activity could be a rational option for treatment.

De novo PMP2 mutations in families with type 1 Charcot-Marie-Tooth disease

We performed whole exome sequencing on a patient with Charcot-Marie-Tooth disease type 1 and identified a de novo mutation in PMP2, the gene that encodes the myelin P2 protein. This mutation (p.Ile52Thr) was passed from the proband to his one affected son, and segregates with clinical and electrophysiological evidence of demyelinating neuropathy. We then screened a cohort of 136 European probands with uncharacterized genetic cause of Charcot-Marie-Tooth disease and identified another family with Charcot-Marie-Tooth disease type 1 that has a mutation affecting an adjacent amino acid (p.Thr51Pro), which segregates with disease. Our genetic and clinical findings in these kindred demonstrate that dominant PMP2 mutations cause Charcot-Marie-Tooth disease type 1.

Use of crop simulation modelling to aid ideotype design of future cereal cultivars

A major challenge of the 21st century is to achieve food supply security under a changing climate and roughly a doubling in food demand by 2050 compared to present, the majority of which needs to be met by the cereals wheat, rice, maize, and barley. Future harvests are expected to be especially threatened through increased frequency and severity of extreme events, such as heat waves and drought, that pose particular challenges to plant breeders and crop scientists. Process-based crop models developed for simulating interactions between genotype, environment, and management are widely applied to assess impacts of environmental change on crop yield potentials, phenology, water use, etc. During the last decades, crop simulation has become important for supporting plant breeding, in particular in designing ideotypes, i.e. 'model plants', for different crops and cultivation environments. In this review we (i) examine the main limitations of crop simulation modelling for supporting ideotype breeding, (ii) describe developments in cultivar traits in response to climate variations, and (iii) present examples of how crop simulation has supported evaluation and design of cereal cultivars for future conditions. An early success story for rice demonstrates the potential of crop simulation modelling for ideotype breeding. Combining conventional crop simulation with new breeding methods and genetic modelling holds promise to accelerate delivery of future cereal cultivars for different environments. Robustness of model-aided ideotype design can further be enhanced through continued improvements of simulation models to better capture effects of extremes and the use of multi-model ensembles.

Alteration of ornithine metabolism leads to dominant and recessive hereditary spastic paraplegia

Hereditary spastic paraplegias are heterogeneous neurological disorders characterized by a pyramidal syndrome with symptoms predominantly affecting the lower limbs. Some limited pyramidal involvement also occurs in patients with an autosomal recessive neurocutaneous syndrome due to ALDH18A1 mutations. ALDH18A1 encodes delta-1-pyrroline-5-carboxylate synthase (P5CS), an enzyme that catalyses the first and common step of proline and ornithine biosynthesis from glutamate. Through exome sequencing and candidate gene screening, we report two families with autosomal recessive transmission of ALDH18A1 mutations, and predominant complex hereditary spastic paraplegia with marked cognitive impairment, without any cutaneous abnormality. More interestingly, we also identified monoallelic ALDH18A1 mutations segregating in three independent families with autosomal dominant pure or complex hereditary spastic paraplegia, as well as in two sporadic patients. Low levels of plasma ornithine, citrulline, arginine and proline in four individuals from two families suggested P5CS deficiency. Glutamine loading tests in two fibroblast cultures from two related affected subjects confirmed a metabolic block at the level of P5CS in vivo. Besides expanding the clinical spectrum of ALDH18A1-related pathology, we describe mutations segregating in an autosomal dominant pattern. The latter are associated with a potential trait biomarker; we therefore suggest including amino acid chromatography in the clinico-genetic work-up of hereditary spastic paraplegia, particularly in dominant cases, as the associated phenotype is not distinct from other causative genes.

Physical activity, body mass index and mental health in Chinese adolescents: a population based study

AIM

The aim of the present study was to examine the association between physical activity, BMI level and mental health among Chinese adolescents.

METHODS

Three thousand ninety-six adolescents aged 11 to 13 were analyzed from 6 middle schools of Xuzhou. Physical activity level was measured using self-designed questionnaires. BMI was calculated according to the results of these students' physical examinations. Anxiety symptoms were assessed by using the Screen for Child Anxiety Related Emotional Disorder, depression via the Children's Depression Inventory. Data were analyzed using chi-square test and logistic regression.

RESULTS

Adolescents' self-reported rate of insufficient physical activity was 58.1%. The overweight and obesity rates were 18.4%, 16.0%. The point prevalence rates on anxiety and depression were 15.2%, 11.5%. Insufficient physical activity was positively associated with anxiety and depression (OR [95%CI]: 1.31 [1.06-1.63]; 1.33 [1.04-1.70]). Obesity was positively associated with depression (OR [95%CI]: 1.48 [1.10-2.00]). IS-OB was positively associated with anxiety and depressive (OR [95%CI]: 1.71 [1.19-2.45]; 1.99 [1.33-2.97]).

CONCLUSION

Physical inactivity and overweight/obesity were negatively association with mental health of adolescents, respectively. Meanwhile, to explore the combined effects of physical inactivity and obesity would increase the risk of anxiety and depression in adolescents.