[The prospect and challenge of liquid biopsy in the diagnosis and treatment of chest malignancy]

In recent years, the incidence of chest malignant tumors in China has increased year by year, which has seriously threatened the health problems of people. Among them, early screening and intervention of patients with chest malignancies is the key to cancer prevention. Early detection, early diagnosis, and early treatment as the "three early prevention" of clinical practice are conducive to improve the survival rate of tumor patients. As a non-invasive and real-time reflection of tumor status, liquid biopsy has gradually received attention in clinical diagnosis and treatment. Circulating tumor cells (CTCs), circulating tumor DNA (ctDNA) and exosomes as liquid biopsy "Three carriages" are not only widely used in the diagnosis, monitoring and prognostic evaluation of chest malignancies, but also face many unknown challenges. In this article, the application of liquid biopsy in chest malignancies in recent years is elaborated in detail, which provides a reference for the formulation of clinical tumor prevention and diagnosis and treatment strategies.

[Study on the expression of p62 protein in patients with lung adenocarcinoma]

To explore the expression of p62 protein in lung adenocarcinoma (LUAD). In this study, a cross-sectional study was adopted. From December 2011 to May 2013, 60 patients with lung adenocarcinoma who were diagnosed and treated in Tongji Hospital of Tongji University, Shanghai were selected for paraffin embedding and tissue chip preparation, and immunohistochemistry (IHC) technology was used to detect the expression of p62 in lung adenocarcinoma patients' cancer tissues and adjacent tissues, and analyze the relationship between p62 expression and the clinicopathological characteristics and survival prognosis of patients with lung adenocarcinoma; at the same time, 6 cases of lung adenocarcinoma were selected by random sampling cancer tissues and adjacent tissues were detected by Western Blot (WB) to detect p62 protein and analyzed by gray value. Preoperative examination specimens of inpatients with lung adenocarcinoma diagnosed from April 2018 to early October 2019, and plasma specimens of healthy subjects were collected, and enzyme linked immunosorbent assay (ELISA) was used to detect lung adenocarcinoma patients and healthy patients. The expression of p62 in the plasma of the subjects was statistically analyzed using SPSS 22.0 software. The results of IHC showed that the positive expression rate of p62 in cancer tissues was significantly higher than that in adjacent tissues, and the difference was statistically significant (t=5.593, P<0.001). Similarly, WB results showed that the expression of p62 protein in cancer tissues was significantly higher than that in adjacent tissues. It is statistically relevant (t=2.238, P=0.049). The expression of p62 was statistically correlated with tumor size, clinicopathological stage and lymph node metastasis in patients with lung adenocarcinoma (all P<0.05). The overall survival of patients with lung adenocarcinoma with high p62 expression was worse than that of patients with low p62 expression (95%CI was 0.238-0.870, P=0.028), suggesting that the high expression of p62 is related to the poor prognosis of patients with lung adenocarcinoma. The level of p62 protein in the plasma of patients with lung adenocarcinoma was significantly higher than that in the healthy control group. The difference was statistically significant (t=8.533, P<0.001). The area under the receiver operating characteristic curve was 0.835 (95%CI was 0.779-0.891, P<0.001), which is significantly higher than CEA, CA125, CA153 and other single traditional indicators, and the combined detection of four indicators has the highest diagnostic efficiency. p62 was strongly expressed in cancer tissues and serum, which is related to the poor prognosis and overall survival rate of LUAD patients.

[Effect of the vacuum-formed retainer on preventing the proximal contact loss between implant supported crown and adjacent natural teeth]

OBJECTIVE

To evaluate the effect of the vacuum-formed retainer on preventing the proximal contact loss between the implant supported crown and its adjacent natural teeth.

METHODS

Forty-six posterior implant crowns in the mandible including 92 interproximal contacts in 46 patients (19 men, 27 women) aged from 25 to 66 years were included. The participants in experimental group (22 cases) were vacuum-formed retainers at night, while participants in control group (24 cases) only received routine examination. The two groups were not different in age, gender, the time interval of the tooth loss and tooth position at baseline. Mesial and distal proximal contact tightness was measured using the orthodontic dynamometer and metallic articulating film immediately after crown delivery, and 1-month, 3-month, 6-month, and 1-year follow-up respectively. The articulating film was inserted interdentally from the occlusal direction, and then it was slowly removed in the buccallingual direction by the dynamometer. Increasing the number of films (N) piece by piece until the frictional force (F) was great than 0, and the number of films (N) was recorded. At each follow-up, proximal contact between implant crown and its adjacent teeth was considered to be loss if the number of films (N) used at immediate crown delivery passed without frictional force (F=0). Besides, the periodontal conditions [scored according to the probing depth (PD), bleeding index (BI), mobility (M)] and complaint of food impaction were recorded. The mesial and distal proximal contact loss rates were compared between the two groups at different times. Chi-square test or Fisher's exact test was used for statistical analysis.

RESULTS

The proximal contact loss rate on the mesial surface of the implant supported crown continuously increased over the follow-up periods. At the end of the 1-, 3-, and 6-month follow ups, 18.2%, 22.7% and 27.3% were identified for the contact loss rates on the mesial surface of the implant supported crown in the experimental group, respectively. Meanwhile in control group, the rates were 20.8%, 37.5% and 45.8%. No significant differences were observed at the end of the 1-, 3-, and 6-month follow ups(1-month: χ²=0.000, P=1.000; 3-month: χ²=1.183, P=0.277; 6-month: χ²=1.697, P=0.193). The proximal contact loss rate on the mesial surface in control group (62.5%) was significantly higher than that in the experimental group (31.8%, χ²=4.330, P=0.037) at the end of the 1-year follow-up. However, no statistical difference was found on the distal surfaces between the two groups during the whole follow-up periods. The first open contact was noted 1 month after crown insertion.

CONCLUSION

By wearing vacuum-formed retainer for one year, the incidence of open contacts between the posterior implant prostheses and mesial adjacent teeth in the mandible has been reduced.

GM1-gangliosidosis in American black bears: clinical, pathological, biochemical and molecular genetic characterization

G(M1)-gangliosidosis is a rare progressive neurodegenerative disorder due to an autosomal recessively inherited deficiency of lysosomal β-galactosidase. We have identified seven American black bears (Ursus americanus) found in the Northeast United States suffering from G(M1)-gangliosidosis. This report describes the clinical features, brain MRI, and morphologic, biochemical and molecular genetic findings in the affected bears. Brain lipids were compared with those in the brain of a G(M1)-mouse. The bears presented at ages 10-14 months in poor clinical condition, lethargic, tremulous and ataxic. They continued to decline and were humanely euthanized. The T(2)-weighted MR images of the brain of one bear disclosed white matter hyperintensity. Morphological studies of the brain from five of the bears revealed enlarged neurons with foamy cytoplasm containing granules. Axonal spheroids were present in white matter. Electron microscopic examination revealed lamellated membrane structures within neurons. Cytoplasmic vacuoles were found in the liver, kidneys and chondrocytes and foamy macrophages within the lungs. Acid β-galactosidase activity in cultured skin fibroblasts was only 1-2% of control values. In the brain, ganglioside-bound sialic acid was increased more than 2-fold with G(M1)-ganglioside predominating. G(A1) content was also increased whereas cerebrosides and sulfatides were markedly decreased. The distribution of gangliosides was similar to that in the G(M1)-mouse brain, but the loss of myelin lipids was greater in the brain of the affected bear than in the brain of the G(M1) mouse. Isolated full-length cDNA of the black bear GLB1 gene revealed 86% homology to its human counterpart in nucleotide sequence and 82% in amino acid sequence. GLB1 cDNA from liver tissue of an affected bear contained a homozygous recessive T(1042) to C transition inducing a Tyr348 to His mutation (Y348H) within a highly conserved region of the GLB1 gene. The coincidence of several black bears with G(M1)-gangliosidosis in the same geographic area suggests increased frequency of a founder mutation in this animal population.

Receptor-specific delivery of protein antigen to dendritic cells by a nanoemulsion formed using top-down non-covalent click self-assembly

A new class of targeted and immune-evading nanocarrier made using only biological components and facile processes is assembled in a bottom-up fashion. Simple top-down sequential addition of immune-evading or receptor-specific antibody elements conjugated to biosurfactant protein DAMP4 promotes self-assembly at an interface previously formed in the presence of peptide surfactant AM1, leading to a functional display at the interface through non-covalent molecular self-assembly.

Receptor-specific delivery of protein antigen to dendritic cells by a nanoemulsion formed using top-down non-covalent click self-assembly

A new class of targeted and immune-evading nanocarrier made using only biological components and facile processes is assembled in a bottom-up fashion. Simple top-down sequential addition of immune-evading or receptor-specific antibody elements conjugated to biosurfactant protein DAMP4 promotes self-assembly at an interface previously formed in the presence of peptide surfactant AM1, leading to a functional display at the interface through non-covalent molecular self-assembly.

Pathology of GM2 gangliosidosis in Jacob sheep

The G(M2) gangliosidoses are a group of lysosomal storage diseases caused by defects in the genes coding for the enzyme hexosaminidase or the G(M2) activator protein. Four Jacob sheep from the same farm were examined over a 3-year period for a progressive neurologic disease. Two lambs were 6-month-old intact males and 2 were 8-month-old females. Clinical findings included ataxia in all 4 limbs, proprioceptive deficits, and cortical blindness. At necropsy, the nervous system appeared grossly normal. Histologically, most neurons within the brain, spinal cord, and peripheral ganglia were enlarged, and the cytoplasm was distended by foamy to granular material that stained positively with Luxol fast blue and Sudan black B stains. Other neuropathologic findings included widespread astrocytosis, microgliosis, and scattered spheroids. Electron microscopy revealed membranous cytoplasmic bodies within the cytoplasm of neurons. Biochemical and molecular genetic studies confirmed the diagnosis of G(M2) gangliosidosis. This form of G(M2) gangliosidosis in Jacob sheep is very similar to human Tay-Sachs disease and is potentially a useful animal model.

Tay-Sachs disease in Jacob sheep

Autopsy studies of four Jacob sheep dying within their first 6-8 months of a progressive neurodegenerative disorder suggested the presence of a neuronal storage disease. Lysosomal enzyme studies of brain and liver from an affected animal revealed diminished activity of hexosaminidase A (Hex A) measured with an artificial substrate specific for this component of β-hexosaminidase. Absence of Hex A activity was confirmed by cellulose acetate electrophoresis. Brain lipid analyses demonstrated the presence of increased concentrations of G(M2)-ganglioside and asialo-G(M2)-ganglioside. The hexa cDNA of Jacob sheep was cloned and sequenced revealing an identical number of nucleotides and exons as in human HexA and 86% homology in nucleotide sequence. A missense mutation was found in the hexa cDNA of the affected sheep caused by a single nucleotide change at the end of exon 11 resulting in skipping of exon 11. Transfection of normal sheep hexa cDNA into COS1 cells and human Hex A-deficient cells led to expression of Hex S but no increase in Hex A indicating absence of cross-species dimerization of sheep Hex α-subunit with human Hex β-subunits. Using restriction site analysis, the heterozygote frequency of this mutation in Jacob sheep was determined in three geographically separate flocks to average 14%. This large naturally occurring animal model of Tay-Sachs disease is the first to offer promise as a means for trials of gene therapy applicable to human infants.

[Effects of rhTNF-alpha on the secretion of angiogenesis-related growth factors of human adipose tissue-derived stromal cells before and after osteogenic differentiation]

OBJECTIVE

To investigate the proliferation and the secretion of vascular endothelial growth factor(VEGF), fibroblast growth factor-2(FGF-2) and insulin-like growth factor-1(IGF-1) of human adipose tissue-derived stromal cells(hADSCs) before and after osteogenic differentiation under the stimuli of recombinant human tumor necrosis factor alpha (rhTNF-alpha).

METHODS

hADSCs were obtained from human lipoaspirates. All the cells used were at passage four. The proliferation of hADSCs was measured with MTT assays 48, 72, 96 hours after being treated with 0, 1, 5, 10, 50 or 100 microg/L rhTNF-alpha respectively. The secretion of VEGF, FGF-2 and IGF-1 of the undifferentiated hADSCs under stimuli of rhTNF-alpha with the above 5 concentration grades was observed and the secretion of these 3 growth factors of hADSCs at different stages of osteogenic differentiation under stimuli of 10 microg/L rhTNF-alpha was also observed. All the supernatants were harvested for measuring after 24 hours' incubation with rhTNF-alpha. The secretion of VEGF, FGF-2 and IGF-1 was measured with ELISA, and the values were normalized to the cell number of the corresponding wells.

RESULTS

The effect of rhTNF-alpha on the proliferation of hADSCs varied with the concentration and time. Compared with the control(0 microg/L), 10 microg/L rhTNF-alpha showed no suppression or acceleration on proliferation of hADSCs at hour 48, but significantly promoted the proliferation at hour 96 (0.903+/-0.042 vs 0.810+/-0.011, P<0.01), 100 microg/L rhTNF-alpha seemed to suppress the proliferation at hour 48 (0.317+/-0.024 vs 0.458+/-0.046, P<0.01), but appeared to promote it (0.956+/-0.030 vs 0.810+/-0.011, P<0.01) at hour 96. rhTNF-alpha(1, 5, 10, 50 and 100 microg/L) significantly increased VEGF, FGF-2 and IGF-1 production of hADSCs versus the control (0 microg/L) (P<0.01). After osteogenic differention, the secretion of the three growth factors of hADSCs (without rhTNF-alpha treated) was elevated with the days increasing. Under the stimulus of 10 microg/L rhTNF-alpha, the hADSCs after 1 day of osteogenic differentiation significantly increased the secretion of VEGF (P<0.01) compared with the group without rhTNF-alpha treated; after 3 and 7 days of osteogenic differentiation, the hADSCs significantly increased the secretion of VEGF (P<0.01), FGF-2 (P<0.05)and IGF-1 (P<0.05). However, after 14 days of osteogenic differentiation, 10 microg/L rhTNF-alpha appeared to suppress the production of VEGF (P<0.01), FGF-2 (P<0.05) and IGF-1 (P<0.05) of the differentiated hADSCs.

CONCLUSION

Within certain concentration range, rhTNF-alpha can promote the proliferation of hADSCs and the production of VEGF, FGF-2 and IGF-1. The effect of 10 microg/L rhTNF-alpha on the production of VEGF, FGF-2 and IGF-1 of the differentiated hADSCs varied at different stages of osteogenic differentiation.

Spontaneous appearance of Tay-Sachs disease in an animal model

Tay-Sachs disease (TSD) is a progressive neurodegenerative disorder due to an autosomal recessively inherited deficiency of beta-hexosaminidase A (Hex A). Deficiency of Hex A in TSD is caused by a defect of the alpha-subunit resulting from mutations of the HEXA gene. To date, there is no effective treatment for TSD. Animal models of genetic diseases, similar to those known to exist in humans, are valuable and essential research tools for the study of potentially effective therapies. However, there is no ideal animal model of TSD available for use in therapeutic trials. In the present study, we report an animal model (American flamingo; Phoenicopterus ruber) of TSD with Hex A deficiency occurring spontaneously in nature, with accumulation of G(M2)-ganglioside, deficiency of Hex A enzymatic activity, and a homozygous P469L mutation in exon 12 of the hexa gene. In addition, we have isolated the full-length cDNA sequence of the flamingo, which consists of 1581 nucleotides encoding a protein of 527 amino acids. Its coding sequence indicates approximately 71% identity at the nucleotide level and about 72.5% identity at the amino acid level with the encoding region of the human HEXA gene. This animal model, with many of the same features as TSD in humans, could represent a valuable resource for investigating therapy of TSD.

Rapid detection of three large novel deletions of the aspartoacylase gene in non-Jewish patients with Canavan disease

Canavan disease (CD), an autosomal recessive neurodegenerative disorder, is caused by mutations in the aspartoacylase (ASPA) gene. In the present study, the ASPA gene was analyzed in 24 non-Jewish patients with CD from 23 unrelated families. Within this cohort, we found three large novel deletions of approximate 92, 56, and 12.13 kb in length, using both self-ligation of restriction endonuclease-digested DNA fragments with long-distance inverse PCR and multiplex dosage quantitative PCR analysis of genomic DNA. The 92 kb large deletion results in complete absence of the ASPA gene in one homozygous and one compound heterozygous patient, respectively. The 56 kb large deletion causes absence of the majority of the ASPA gene except for exon 1 alone in a compound heterozygous patient. The 12.13 kb deletion involves deletion of the ASPA gene from intron 3 to intron 5 including exons 4 and 5 (I3 to E4E5I5) in a compound heterozygous patient. Patients with the three large deletions clinically manifested severe symptoms at birth, including seizures. Our study showed that the combined use of long-distance inverse PCR and multiplex dosage quantitative PCR analysis of genomic DNA is a helpful and rapid technique to search for large deletions, particularly for detection of large deletions in compound heterozygous patients.

Identification and characterization of novel mutations of the aspartoacylase gene in non-Jewish patients with Canavan disease

Canavan disease, an inherited leukodystrophy, is caused by mutations in the aspartoacylase (ASPA) gene. It is most common among children of Ashkenazi Jewish descent but has been diagnosed in many diverse ethnic groups. Two mutations comprise the majority of mutant alleles in Jewish patients, while mutations in the ASPA gene among non-Jewish patients are different and more diverse. In the present study, the ASPA gene was analysed in 22 unrelated non-Jewish patients with Canavan disease, and 24 different mutations were found. Of these, 14 are novel, including five missense mutations (E24G, D68A, D249V, C152W, H244R), two nonsense mutations (Q184X, E214X), three deletions (923delT, 33del13, 244delA), one insertion mutation (698insC), two sequence variations in one allele ([10T>G; 11insG]), an elimination of the stop codon (941A>G, TAG-->TGG, X314W), and one splice acceptor site mutation (IVS1 - 2A>T). The E24G mutation resulted in substitution of an invariable amino acid residue (Glu) in the first esterase catalytic domain consensus sequence. The IVS1 - 2A>T mutation caused the retention of 40 nucleotides of intron 1 upstream of exon 2. The results of transient expression of the mutant ASPA cDNA containing these mutations in COS-7 cells and assays for ASPA activity of patient fibroblasts indicated that these mutations were responsible for the enzyme deficiency. In addition, patients with the novel D249V mutation manifested clinically at birth and died early. Also, patients with certain other novel mutations, including C152W, E214X, X314W, and frame shift mutations in both alleles, developed clinical manifestations at an earlier age than in classical Canavan disease.

Chylomicron remnant uptake is regulated by the expression and function of heparan sulfate proteoglycan in hepatocytes

Chylomicron remnants transport cholesterol from the intestine, and are removed from the circulation principally by the liver. While hepatic receptors, including the low density lipoprotein (LDL) receptor account for endocytosis, heparan sulfate proteoglycans (HSPG) participate in the initial binding of remnants to liver cells. To explore the interactions between HSPG and endocytosis of remnants, in the present study the expression of HSPG was inhibited in HepG2 cells transfected by a synthetic antisense oligodeoxynucleotide SYN5. Immunofluorescent staining by a monoclonal anti-syndecan antibody showed significant reduction in the expression of syndecan in SYN5-treated cells compared with control cells. Remnant binding decreased by about 50-70% in SYN5-transfected cells. Monoclonal antibodies to either heparan sulphate or the LDL receptor decreased binding by about 60-65%. The glycosylation inhibitor beta-nitrophenylxylopyranoside inhibited remnant uptake by 25%, whereas 4-nitrophenyl-beta-D-galactopyranoside had no effect on remnant binding. Heparinase completely abolished binding at appropriate concentrations. Heparitinase was less effective than hep arinase in inhibiting remnant binding. Suramin completely abolished the remnant binding. Poly-arginine, poly-lysine, and protamine all reduced remnant uptake by the cells, as did polybrene, a synthetic polycation, suggesting a role of cation-anion interactions in remnant binding. Brefeldin A, colchicine, and monensin caused the fluorescence associated with remnants to persist within the cells, confirming that blockers of tubulovesicular processes and Golgi function inhibit the intracellular transport and degradation of the remnants. Our results show that remnant binding to liver cells depends on the LDL receptor, on the expression of HSPG core proteins, and on the functionality of heparan sulfate in HSPG.

Correlation of glioma cell regression with inhibition of insulin-like growth factor 1 and insulin-like growth factor-binding protein-2 expression

To explore the antitumor effect of insulin-like growth factor 1 (IGF-I) antisense RNA and the interaction of IGF-I with insulin-like growth factor-binding proteins (IGFBPs) in glioma cells, a recombinant retrovirus expressing IGF-I antisense RNA was constructed and introduced into C6 glioma cells. IGF-I antisense RNA reverses the transformed phenotype in glioma cells and inhibits glioma cell growth by blocking overexpression of endogenous IGF-I. Expression of IGFBP-2 is increased in glioma cells as compared with normal adult glial cells. IGF-I antisense RNA also inhibits expression of IGFBP-2 in glioma cells, but does not influence expression of the other IGFBPs. Although IGFBP-2 in conditioned medium from wild-type C6 cell cultures itself does not directly influence glioma cell growth, it synergistically enhances exogenous IGF-I-mediated DNA synthesis in IGF-I-negative C6 cells. These findings indicate the inhibitory effect of IGF-I antisense RNA on growth and development of glioma cells. IGF-I-dependent glioma cell growth may, in some circumstances, require IGFBP-2 as a cofactor. The antitumor effect of IGF-I antisense RNA is also associated with inhibition of IGFBP-2 expression.

Use of gene-manipulated models to study the physiology of lipid transport

1. In vivo and in vitro gene-manipulated models were used to study the metabolism of chylomicron remnants. Transgenic mice expressing human apolipoprotein (Apo) A1 or E4, gene knockout mice deficient in ApoE or low density lipoprotein (LDL) receptors and antisense gene inhibition in HepG2 cells were used to evaluate the effect of gene manipulations on the metabolism of chylomicron remnants. 2. Mice transgenic for human ApoE4 showed accelerated clearance of chylomicron-like emulsions when animals were fed a low-fat diet. When challenged by a high-fat diet, remnant clearance in ApoE4 transgenic mice was delayed, as in normal or non-transgenic controls. However, unlike normal nontransgenic controls, in ApoE4 transgenic mice high density lipoprotein (HDL)-cholesterol levels remained high after high-fat feeding, which probably protected the animals from the development of atherosclerosis. In contrast, clearance of chylomicron-like lipid emulsions was not affected by the over-expression of human ApoAI in transgenic mice. 3. Gene knock-out mice deficient in ApoE or deficient in the LDL receptor were used to show that ApoE and LDL receptors are both essential for the normal, fast catabolism of chylomicron remnants by the liver. In the absence of the LDL receptor, an alternative ApoE-dependent pathway operates to clear chylomicrons from the plasma, with significantly delayed catabolism. 4. Antisense gene inhibition techniques were used to suppress the expression of syndecan, a core protein of heparan sulfate proteoglycan, in HepG2 cells. Remnant uptake in cells transfected with the antisense oligodeoxynucleotide complementary to a 20 nucleotide sequence upstream of the initiation site of syndecan cDNA markedly reduced the uptake of chylomicron remnant.

Cloning of a unique sequence specific to isolates of type B:2 Pasteurella multocida

Two Carter type B Pasteurella multocida isolates, Izatnagar 52 and 25, isolated from cases of haemorrhagic septicaemia (HS), were used in a modified subtractive hybridisation technique with the specific aim of cloning unique DNA sequences related to the pathogenesis of HS. Biochemical and protein analyses have shown these isolates to be similar, but reports indicate that they have differences in pathogenicity. The subtracted inserts were screened against genomic DNA from a wide range of P multocida isolates, with two distinct fragments demonstrating specific hybridisation with Carter type B isolates that cause HS. No identity was observed with either Carter type E isolates or non-HS type B strains. The clones were sequenced and a search of the GenBank database revealed significant identity of the clone A3b (296 nt) to P haemolytica lipoprotein, whereas there was no significant identity with 6b (956 nt). Both these fragments had a high level of identity (72.8 to 76.9 per cent) to the H influenzae Rd genome.