Expression characteristics and risk analysis of BRCA1 and BRCA2 gene variants in colorectal cancer / 国际外科学杂志

Objective:To explore the relationship between the occurrence and development of colorectal cancer and the risk of BRCA1 and BRCA2 gene mutations. Methods:Sixty-one patients with colorectal adenocarcinoma admitted to Beijing Friendship Hospital Affiliated to Capital Medical University from January 2022 to March 2022 were tested by second-generation sequencing. Information such as age of onset, gender, histological grade and TNM stage were collected. According to whether the BRCA1 and BRCA2 gene had systemic mutation, the patients were divided into BRCA1 and BRCA2 gene system mutation group and unmutated group. There were 8 cases in the BRCA1 and BRCA2 gene system mutant group and 53 cases in the non-mutant group. The main outcome measures were the relationship between pathogenic or likely pathogenic germline mutations in colorectal cancer and clinicopathological data of patients, including age of onset, gender, tumor location, TNM stage, histological differentiation, and family history. The secondary outcome was the relationship between BRCA1 and BRCA2 gene system mutations and clinicopathological data. Measurement data with normal distribution were expressed as mean±standard deviation ( ± s), and comparison between groups was analyzed using the t-test. Measurement data with non-normal distribution were represented as M ( Q1, Q3), and comparison between groups was analyzed using the Mann-Whitney U test. Measurement data were expressed as the number of cases or percentage (%), and Chi-square test was used for comparison between groups. Results:Among 61 colorectal adenocarcinoma patients, the frequency of pathogenic or potentially pathogenic germ line mutations in colorectal cancer was 13.1% (8/61), and the frequency of BRCA1 and BRCA2 mutations was 3.3% (2/61). The frequency of BRCA1 and BRCA2 mutations was 13.1% (8/61). Women with BRCA1 and BRCA2 mutations (75.0% vs 37.7%, χ2=3.947, P=0.047) and right colon cancer (75.0% vs 26.4%, χ2=7.889, P=0.019) were significantly higher than those without mutation. Conclusions:The frequency of BRCA1 and BRCA2 gene mutation is higher in colorectal cancer patients. BRCA1 and BRCA2 gene mutations are recommended for colorectal cancer patients with a family history of breast or ovarian cancer.

Genetic analysis of a case of infant spinal muscular atrophy type 1c / 中国综合临床

Objective:To summarize the genetic characteristics of a case of spinal muscular atrophy type 1c.Methods:The case data of a child with spinal muscular atrophy type 1c was retrospectively analyzed, and the genetic analysis and literature review were carried out.Results:The patient, male, started at the age of 2 months, and showed gross motor development backwardness and low muscular tension. Multiplex connection probe amplification technique showed that the child had homozygous deletion mutation in exon 7-8 of SMN1 gene, and there was duplicate mutation in exon 7-8 of SMN2 gene. The number of copies of exon 7/8 was 3/3. His father was a heterozygous deletion carrier of SMN1 gene, and there was homozygous mutation in exon 8 of SMN2 gene. The number of copies of exon 7/8 was 2/3. His mother did not find abnormal exons of SMN1 gene, and the number of copies of exon 7/8 of SMN2 gene was 1/1.Conclusion:Spinal muscular atrophy lacks specific manifestations in the early stage, and the diagnosis mainly depends on genetic testing. Clinicians need to be vigilant, strengthen the early understanding of the disease, and improve the prognosis.

Mecanismos de Variación Antigénica en Anaplasma marginale / Mechanisms of Antigenic Variation in Anaplasma marginale

Anaplasma marginale (A. marginale), es una bacteria del orden de las Rickettsias que ocasiona la anaplasmosis bovina en regiones tropicales y subtropicales del mundo. Esta enfermedad, trasmitida principalmente por tábanos y garrapatas, se desarrolla típicamente en una etapa inicial aguda con manifestaciones clínicas caracterizadas principalmente por anemia y fiebre. Después de un par de meses, los animales recuperan su condición física y se hacen asintomáticos, siendo incapaces de eliminar completamente la bacteria, convirtiéndose en animales persistentemente infectados. Esto se debe a la capacidad de A. marginale para evadir el sistema inmune. En este sentido, se ha demostrado la existencia de un mecanismo de variación antigénica en las proteínas MSP1, MSP2 y MSP3 de la bacteria. Al evaluar la familia multigénica que codifica para la MSP2, se determinó que está conformada por dos regiones conservadas que flanquean una región central hipervariable. De esta manera, al expresarse cada una de las 52 variables de la MSP2, se expresa un epítope diferente. Cuando se describió el genoma completo de este hemotrópico, se encontró también la presencia de 16 pseudogenes msp2, los cuales pueden ser recombinados dentro del sitio de expresión del operón de la MSP2, constituyendo un segundo mecanismo de variación. Además de ello, los fragmentos hipervaribles y los pseudogenes se pueden combinar entre sí, en un proceso denominado conversión génica, creando nuevos epítopes “recombinantes”, confiriendo una capacidad de variabilidad antigénica casi infinita al A. marginale (tercer mecanismo). Un cuarto mecanismo de variación antigénica, lo constituye la dimerización de la MSP2 sobre la superficie del A. marginale, debido a que la expresión simultánea de variantes conforman epítopes únicos. En conclusión, la recombinación génica de la MSP2 y su dimerización en la membrana, constituye un mecanismo muy eficiente de variación antigénica para eludir el sistema inmunológico del hospedador.

Anaplasma marginale (A. marginale) is a bacterium of the Rickettsiales order that causes bovine anaplasmosis in tropical and subtropical regions worldwide. This disease, mainly transmitted by ticks and horseflies, typically develops in an initial acute stage, with clinical signs characterized by anemia and fever. After two months, animals recover their original physical condition and become asymptomatic, being unable to completely eliminate the bacterium, turning into persistently infected animals. This is due to the ability of A.marginale to evade the immune system. In this regard, the existence of a mechanism for antigenic variation in proteins of the bacterium, such as MSP1, MSP2, and MSP3, has been demonstrated. When assessing the multigenic family which encodes for MSP2, it was determined that it consists of two conserved regions flanking a central hypervariable region. Thus, when expressing each of the 52 MSP2 variables, a different epitope is also expressed. When the entire genome of this parasite was decoded, the presence of 16 pseudogenes for MSP2 was also discovered. These pseudogenes can be recombined within the operon expression site of MSP2, providing a second mechanism of variation. Moreover, both the hypervariable fragments and pseudogenes can combine among them, in a process called gene conversion, creating new “recombinant” epitopes, conferring the A. marginale with an almost infinite capacity for antigenic variability (third mechanism). A fourth mechanism of antigentic variation consists of the dimerization of MSP2 on the surface of A. marginale, because the simultaneous expression of variants creates unique epitopes. In conclusion, gene recombination of MSP2 along with the dimerization of MSP2 on the membrane provides a very efficient mechanism for antigenic variation for evading the host’s immune system.

Prediction of conversion to psychosis: review and future directions / Previsão de conversão para psicose: revisão e perspectivas futuras

This article reviews recent findings on predictors of conversion to psychosis among youth deemed at ultra high risk (UHR) based on the presence of subpsychotic-intensity symptoms or genetic risk for psychosis and a recent decline in functioning. Although transition rates differ between studies, the most well powered studies have observed rates of conversion to full psychosis in the 30-40 percent range over 2-3 years of follow-up. Across studies, severity of subthreshold positive symptoms, poorer social functioning, and genetic risk for schizophrenia appear to be consistent predictors of conversion to psychosis, with algorithms combining these indicators achieving positive predictive power > 80 percent. Nevertheless, a substantial fraction of UHR cases do not convert to psychosis. Recent work indicates that UHR cases who present with lower levels of negative symptoms and higher levels of social functioning are more likely to recover symptomatically and no longer meet criteria for an at-risk mental state. In general, it appears that about 1/3 of UHR cases convert to psychosis, about 1/3 do not convert but remain symptomatic and functionally impaired, and about 1/3 recover symptomatically and functionally. Continued efforts to detect early risk for psychosis are critical for informing early intervention and provide increasing promise of delaying or even preventing the onset of psychosis.

O presente artigo revisa os achados recentes sobre os preditores de conversão para psicose entre jovens considerados de ultra alto risco (UAR) com base na presença de sintomas de intensidade sub-psicótica e risco genético para psicose e declínio recente no funcionamento mental. Apesar das taxas de transição serem diferentes entre os estudos, os estudos de mais peso encontraram taxas de conversão para psicose entre 30 por cento e 40 por cento em pacientes acompanhados por dois a três anos. Entre os estudos, gravidade de sintomas positivos sub-clínicos, pior relacionamento social e risco genético para esquizofrenia parecem ser preditores consistentes de conversão para psicose, com algoritmos combinando esses indicadores alcançando poder preditivo positivo > 80 por cento. Ainda assim, uma fração substancial de casos em UAR não converte para psicose. Trabalhos recentes indicam que casos em UAR que apresentam níveis mais baixos de sintomas negativos e níveis mais altos de bom relacionamento social apresentam maior probabilidade de recuperação dos sintomas e de não mais preencher os critérios para estado mental de risco. Em geral, parece que 1/3 dos casos de UAR convertem para psicose, cerca de 1/3 não convertem, mas se mantém sintomáticos e com comprometimento funcional, e cerca de 1/3 apresentam recuperação sintomática e funcional. Esforços contínuos para detectar risco precoce para psicose são críticos para a intervenção precoce e para fornecer uma promessa cada vez maior de retardar ou até prevenir o início da psicose.

Hepatitis B virus X gene transforms human hepatocyte QSG7701 in vitro / 中华传染病杂志

Objective To observe the effects of hepatitis B virus(HBV)X gene muhifunctional protein(HBx)on the biological characteristics of QSG7701 and the transformational effects on QSG7701 cell.Methods QSG7701 ceils were stably transformed by recombinant plasmid pCMV/X and eukaryotic expressed plasmid pRc/CMV2 by liposome-based assay,respectively.Non-transfeeted QSG7701 cells were employed as controls.The expressions of HBx,c-Myc and Bel-2 proteins in QSG7701 cells were detected by Western blot.MTT colorimetric analysis,flow cytometry and soft agar clone-forming assay were performed tO detect the biolo~dcal activity of cells.Results HBx Drotein was highly expressed in pCMV X/QSG7701 cells.The expression level of c-Myc protein in the pCMV X/QSG7701 cells was much higher than those in the other tWO groups of cells.The expression of Bcl2 protein was detected in the three groups of cells,but the expression levels were similar.Percentage of S stage cells in pCMV X/QSG7701 ceils was significantly higher than those in pRcCMV2/QSG7701 and non-transfected QSG7701 cells E(28.80±2.32)%,(15.5±2.64)%and(21.5±3.66)%,LSD 0.05=3.95%,LSD 0.01=5.47%,P<0.01].While percentage of G1 stage cells in pCMV X/QSG7701 cells was significantly lower than those in pRcCMV2/QSG7701 and non-transfected QSG7701 cells[(62.30±3.85)%,(78.70±4.12)%and(78.10q±4.45)%,LSD 0.05=5.63%,LSD 0.01-7.79 %,P<0.01].The apoptosis rate of pCMV X/QSG7701 cells was much higher than those in pRcCMV2/QSG770t and non-transfected QSG7701 cells[(14.90±1.01)%,(8.91±0.48)%and (4.03±0.47)%,LSD 0.05=O.94%,LSD 0.01=1.31%,P<0.01].The population doubling time of pCMV X/QSG7701 cells was shorter than those in pRcCMV2/QSG and non-trarmfected cells(14 h,29 h,38 h,respectively).The cloning ratio in soft agar of pCMV X/QSG7701 cells WaS significantly higher than those of pRcCMV2/QSG and non-transfected QSG7701 cells[(19.83±1.96)%,(1.76±0.03)%and (1.33±0.18)%,LSD 0.05=1.53%,LSD 0.01=2.11%,P<0.01].Conclusion HBx may transform human non-tumor hepatoeyte QSG7701,which makes the cell growth malignizeA.

Correlation between Genotype and Phenotype in Korean patients with Spinal Muscular Atrophy / 대한소아신경학회지

BACKGROUND: Spinal muscular atrophy (SMA) is the second most common disease with autosomal recessive mode of inheritance in children and characterized by degeneration of anterior horn cells of the spinal cord resulting in weakness and wasting of voluntary muscles. This disease is caused by deletion of many candidate genes including SMN, p44, NAIP on chromosome 5q11.2-13.3. Although molecular characteristics of candidate genes were identified, genotype-phenotype correlation has not been clearly elucidated yet. Nevertheless, gene conversion, previously described as simply as gene deletion, appears to be very important mechanism as a molecular pathogenesis, and even makes more difficult to pursue the correlation. PURPOSE: This study was aimed to define the correlation between genotype and phenotype of SMA in Korean patients. The significance of SMN gene as well as NAIP gene, p44 gene in the progress of disease process and phenotypic correlation with gene conversion was evaluated. This study was also undertaken to determine the frequency of gene rearrangements in normal population. METHOD: Eight type I SMA patients and two type II SMA patients were studied. SMN, NAIP, and p44 gene deletion were analyzed by PCR amplification and restriction enzyme digestion with DraI, DdeI and AluI, respectively. p44 gene was also analyzed by SSCP. Gene conversion was defined by centromeric and telomeric SMN gene exon 7 to exon 8 PCR amplification followed by DdeI restiction enzyme digestion. RESULT: 1) Five of eight type I patients showed deletion of SMN, NAIP and p44 gene, while the rest of type 1 and all type II patients showed deletion of SMN gene only. 2) We examined SMN and NAIP gene deletion on 100 normal newborns, which showed the deletion of centromeric SMN gene in two newborns, the relative frequency of 2% in gene rearrangement. 3) There was one case of type I SMA showing deletion of telomeric SMN exon 7 but not SMN exon 8 suggestive of gene conversion occurred during the recombination as a molecular pathogenesis. CONCLUSION: The major deletion of SMA candidate genes, SMN, NAIP, and p44 gene appear to be involved in severe phenotype since these three candidate genes deletion were noted only in type 1 cases. However, SMN gene deletion only identified both in type 1 and type 2 explains that SMN gene may plan an major role in the pathogenesis of SMA and also suggests that other factors may be affecting the severity in spinal muscular atrophy. One patient with type I which showed the conversion of the centromeric SMN gene to the teleomeric gene strongly supports that SMN gene copy number may not be correlated with the severity in SMA. Our molecular findings suggest that phenotype is not clearly correlated with genotype. Prenatal screening should be carefully undertaken to interpretate because of high frequency of gene rearrangements in normal populations.

Study on the reversion of drug resistance in clinical isolates of E. Coli by EGS technique / 中华传染病杂志

Objective To explore the potential of converting the chloramphenicol resistant clinical E. Coli isolates to chloramphenicol sensitive ones by employing external guide sequence(EGS) technique in vitro. Methods Recombinant plasmids with EGScat 1+2 and tetracycline resistant gene, named PAlterl EGScat1+2, was constructed. Routine Cacl 2 method was used to introduce recombinant plasmid into the chloramphenicol resistant clinical isolates E. Coli 4758. Colony PCR was used to test and A600 was used to detect growth rates in liquid and solid culture of various concentrations of chloramphenicol. Results The chloramphenicol resistant clinical isolates E. Coli 4758 grew well in chloramphenicol(35 ?g/ml, 70 ?g/ml, 105 ?g/ml, 170 ?g/ml) plates whereas the transformants tE4758 with PAlter1 EGScat 1+2 failed to grow in these concentrations, which indicated its resistance to the chloramphenicol was reversed. Conclusions EGS molecules are able to convert the drug resistance in clinical E. Coli isolates in vitro.

Duplication and deletion of 21 hydroxylase gene among the normal Korean subjects and in adrenogenital syndrome patients

Steroid 21 hydroxylase deficiency is a major cause of congenital adrenal hyperplasia(CAH) and is caused by genetic impairment (CYP21B) of this enzyme. In the human genome, CYP21B is located within MHC class III region on the short arm of chromosome 6. Most of the genes in this region are highly polymorphic and crowded. Also the CYP21B gene is accompanied by its pseudogene (CYP21A) and tandemly arranged with two genes of fourth component of complement. This highly complex gene arrangement in this area may predispose genetic unstability of CYP21 genes,i.e. mutations. In the current study, we tried to investigate the frequency of duplication and deletion of CYP21 genes and pattern of the genetic alteration of these genes by RFLPs. We also compared the genetic alteration of CYP21 in normal subjects with those of the CAH patients. According to our study, 15% of the normal Korean population have duplication or deletion of CYP21. There was one normal subject with heterozygous deletion of CYP21B gene. Of the 5 CAH patients examined, we found abnormal patterns in 2 patients. One was a large scale gene conversion and the other was a deletion of CYP21B and C4 locus II genes with gene conversion. These results suggest that high frequency of duplication and deletion of CYP21 and C4 in the general population may provide the genetic pool of instable CYP21 genes and these duplicated or deleted genes may result in gene conversions between CYP21A(pseudogene) and CYP21B(true gene) by preventing the normal recombination event.