Evidence that 3-hydroxy-3-methylglutaric acid promotes lipid and protein oxidative damage and reduces the nonenzymatic antioxidant defenses in rat cerebral cortex

In the present work we investigated the in vitro effect of 3-hydroxy-3-methylglutarate (HMG) that accumulates in 3-hydroxy-3-methylglutaryl-CoA lyase deficiency (HMGLD) on important parameters of oxidative stress in rat cerebral cortex. It was observed that HMG induced lipid peroxidation by significantly increasing chemiluminescence and levels of thiobarbituric acid-reactive substances (TBA-RS). This effect was prevented by the antioxidants alpha-tocopherol, melatonin, N-acetylcysteine, and superoxide dismutase plus catalase, suggesting that free radicals were involved in the lipid oxidative damage. On the other hand, HMG did not change TBA-RS levels in intact or disrupted mitochondrial preparations, indicating that generation of oxidants by this organic acid was dependent on cytosolic mechanisms. HMG also induced protein oxidative damage in cortical supernatants, which was reflected by increased carbonyl content and sulfhydryl oxidation. Furthermore, HMG significantly reduced the nonenzymatic antioxidant defenses total-radical trapping antioxidant potential, total antioxidant reactivity, and reduced glutathione (GSH) levels in rat cerebral cortex. HMG-induced GSH reduction was totally blocked by melatonin pretreatment. We also verified that the decrease of GSH levels provoked by HMG in cortical supernatants was not due to a direct oxidative effect of this organic acid, because exposition of commercial GSH and purified membrane protein-bound thiol groups to HMG in the absence of cortical supernatants did not decrease the reduced sulfhydryl groups. Finally, the activities of the main antioxidant enzymes were not altered by HMG exposure. Our data indicate that oxidative stress elicited in vitro by HMG may possibly contribute at least in part to the pathophysiology of the brain injury in HMGLD.     

Poly(A)-specific ribonuclease deficiency impacts telomere biology and causes dyskeratosis congenita

Dyskeratosis congenita (DC) and related syndromes are inherited, life-threatening bone marrow (BM) failure disorders, and approximately 40% of cases are currently uncharacterized at the genetic level. Here, using whole exome sequencing (WES), we have identified biallelic mutations in the gene encoding poly(A)-specific ribonuclease (PARN) in 3 families with individuals exhibiting severe DC. PARN is an extensively characterized exonuclease with deadenylation activity that controls mRNA stability in part and therefore regulates expression of a large number of genes. The DC-associated mutations identified affect key domains within the protein, and evaluation of patient cells revealed reduced deadenylation activity. This deadenylation deficiency caused an early DNA damage response in terms of nuclear p53 regulation, cell-cycle arrest, and reduced cell viability upon UV treatment. Individuals with biallelic PARN mutations and PARN-depleted cells exhibited reduced RNA levels for several key genes that are associated with telomere biology, specifically TERC, DKC1, RTEL1, and TERF1. Moreover, PARN-deficient cells also possessed critically short telomeres. Collectively, these results identify a role for PARN in telomere maintenance and demonstrate that it is a disease-causing gene in a subset of patients with severe DC.     

Impact of intermediate mammography assessment on the likelihood of false-positive results in breast cancer screening programmes

Objectives  

Breast cancer screening is offered to 100% of the target population in Spain and intermediate mammograms (IMs) are sometimes indicated. This study was aimed at analysing the frequency of IMs, the factors determining their recommendation, and their impact on the risk of false–positive results and the detection rate.     

Induction of immunosuppressive molecules and regulatory T cells counteracts the antitumor effect of interleukin-12-based gene therapy in a transgenic mouse model of liver cancer

BACKGROUND/AIMS: Hepatocellular carcinoma (HCC) often lacks curative treatment; therefore new efficient therapies are needed. In this work we aimed at evaluating the antitumor effect of interleukin-12 (IL-12)-based gene therapy on HCC occurring spontaneously in mice. METHODS: A plasmid-vector expressing IL-12 in a liver-specific and doxycycline (Dox)-inducible manner was transferred by hydrodynamic injection to the liver of L-PK/c-myc mice with HCC. IL-12 expression was induced by administering Dox (3 cycles of 1 month duration separated by 1 month rest). RESULTS: Dox administration increased serum IL-12 and IFN-gamma and induced tumor lymphocytic infiltration in all treated mice which was accompanied by tumor stabilization or regression in 40% of animals. The antitumor effect did not correlate with levels of IL-12 or IFN-gamma nor with the intensity of tumor mononuclear infiltration. However, tumors from non-responder mice showed more abundance of Foxp3+ regulatory T cells and higher expression of the immunosuppressive molecules PD-1, PD-L1, VEGF, CTLA-4, IDO, and IL-10 than those that responded to therapy. CONCLUSIONS: Although long-term induction of IL-12 expression in the liver can inhibit HCC growth, the efficacy of the treatment appears to be limited by the activation of immunosuppressive mechanisms.     

Chronic Temporomandibular Disorders: disability,pain intensity and fear of movement

Background

The objective was to compare and correlate disability, pain intensity, the impact of headache on daily life and the fear of movement between subgroups of patients with chronic temporomandibular disorder (TMD).

Methods

A cross-sectional study was conducted in patients diagnosed with chronic painful TMD. Patients were divided into: 1) joint pain (JP); 2) muscle pain (MP); and 3) mixed pain. The following measures were included: Craniomandibular pain and disability (Craniofacial pain and disability inventory), neck disability (Neck Dsiability Index), pain intensity (Visual Analogue Scale), impact of headache (Headache Impact Test 6) and kinesiophobia (Tampa Scale of Kinesiophobia-11).

Results

A total of 154 patients were recruited. The mixed pain group showed significant differences compared with the JP group or MP group in neck disability (p?<?0.001, d?=?1.99; and p?<?0.001, d?=?1.17), craniomandibular pain and disability (p?<?0.001, d?=?1.34; and p?<?0.001, d?=?0.9, respectively), and impact of headache (p?<?0.001, d?=?1.91; and p?<?0.001, d?=?0.91, respectively). In addition, significant differences were observed between JP group and MP group for impact of headache (p?<?0.001, d?=?1.08). Neck disability was a significant covariate (37 % of variance) of craniomandibular pain and disability for the MP group (β?=?0.62; p?<?0.001). In the mixed chronic pain group, neck disability (β?=?0.40; p?<?0.001) and kinesiophobia (β?=?0.30; p?=?0.03) were significant covariate (33 % of variance) of craniomandibular pain and disability.

Conclusion

Mixed chronic pain patients show greater craniomandibular and neck disability than patients diagnosed with chronic JP or MP. Neck disability predicted the variance of craniofacial pain and disability for patients with MP. Neck disability and kinesiophobia predicted the variance of craniofacial pain and disability for those with chronic mixed pain.

     

Target enrichment and high‐throughput sequencing of 80 ribosomal protein genes to identify mutations associated with Diamond‐Blackfan anaemia

Diamond‐Blackfan anaemia (DBA) is caused by inactivating mutations in ribosomal protein (RP) genes, with mutations in 13 of the 80 RP genes accounting for 50–60% of cases. The remaining 40–50% cases may harbour mutations in one of the remaining RP genes, but the very low frequencies render conventional genetic screening as challenging. We, therefore, applied custom enrichment technology combined with high‐throughput sequencing to screen all 80 RP genes. Using this approach, we identified and validated inactivating mutations in 15/17 (88%) DBA patients. Target enrichment combined with high‐throughput sequencing is a robust and improved methodology for the genetic diagnosis of DBA.