[Clinical efficacy observation of omalizumab on patients with moderate to severe allergic asthma for one year]

To observe the symptom control, pulmonary function changes and safety of use of omalizumab in patients with moderate to severe allergic asthma for 1 year. A small sample self-controlled study before and after treatment was conducted to retrospective analysis involved 17 patients with moderate to severe asthma who received omalizumab therapy for 12 months in Peking University People's Hospital and Beijing Jishuitan Hospital from January 2020 to December 2021. The clinical symptoms and pulmonary function changes were compared before treatment, after 6 months and 12 months of treatment, and the clinical data such as the use of other drugs and adverse reactions were observed. Statistical data are collected using the median method, and non-parametric paired Wilcoxon analysis was used for pairwise comparison. Before treatment with omalizumab, the patients' FeNO value was 79(58, 121) ppb, and the total serum IgE was 228(150.5, 345.5) IU/ml. After 6 months of omalizumab therapy, the percent predicted value of the forced expiratory volume in 1 second (FEV1%) before inhaled bronchodilator increased from 86.70(82.65, 91.35)% to 90.90(87.70, 95.85)% (Z=-3.626, P<0.001). The FEV1%pred after inhaled bronchodilator increased from 92.60(85.75, 96.90)% to 94.30(89.95, 98.15)% (Z=-2.178, P=0.029). The absolute value of improvement in FEV1 decreased from 150(95, 210)ml to 50(20, 125) ml (Z=-2.796, P=0.005), and the improvement rate decreased from 6.60(3.80, 7.85)% to 1.90(0.75, 4.85)% (Z=-2.922, P=0.003). After 12 months of treatment, the FEV1%pred before inhaled bronchodilator further increased to 92.90 (91.60, 98.15)% (Z=-3.575, -2.818, and P<0.001, 0.005 compared with before treatment and 6 months after treatment, respectively). The FEV1%pred after inhaled bronchodilator increased to 96.80 (91.90, 101.25)% (Z=-3.622, -1.638, and P<0.001, 0.008 compared with before treatment and after 6 months of treatment, respectively). The absolute value of improvement in FEV1 was 70 (35, 120) ml (P=0.004, 0.842 before treatment and 6 months after treatment, respectively), and the improvement rate was 3.0(1.0, 5.0)% (Z=-2.960, -0.166, and P=0.003, 0.868, compared with before treatment and after 6 months of treatment, respectively). After 12 months of treatment, ACT increased from 13 (10.5, 18) before treatment to 24 (23, 25) (Z=-3.626,P<0.001). Only 1 patient experienced an injection site skin reaction during treatment. Therefore, after 6 months and 12 months of treatment with omalizumab, the patient's lung function improved and symptoms were relieved, which could effectively prevent the acute exacerbation of asthma. Omalizumab treatment is safe and well tolerated, and no effect on blood pressure and blood glucose was observed.

[Efficacy of fenestrated atrial septal defect occulders on pulmonary hypertension dogs]

Objective: To explore the short-term efficacy of fenestrated atrial septal defect (ASD) occulders in the treatment of pulmonary arterial hypertension (PAH). Methods: Thirty-six healthy dogs were divided into the balloon atrial septostomy (BAS)+fenestrated ASD occulders group (n=12), BAS group (n=12) and non-septostomy group (n=12). PAH was induced by intra-atrial injection of dehydrogenized monocrotaline (1.5 mg/kg) in all dogs. Animals in the BAS+fenestrated ASD occulders group underwent atrial septal puncture and fenestrated ASD occulders implantation. Animals in the BAS group underwent balloon atrial septostomy. The non-septostomy group received no surgical intervention. The hemodynamic indexes and blood N-terminal pro-B-type natriuretic peptide (NT-proBNP) of dogs were measured before modeling, 2 months after modeling, 1, 3, and 6 months after surgery, respectively. Echocardiography was performed to observe the patency of the shunt and atrial septostomy of the dogs in the BAS+fenestrated ASD occulders group and BAS group at 1, 3, and 6 months after surgery. Three dogs were sacrificed in each group at 1, 3, and 6 months after surgery, respectively. Atrial septal tissue and fenestrated ASD occulders were removed to observe the patency and endothelialization of the device. Lung tissues were obtained for hematoxylin-eosin (HE) staining to observe the inflammatory cells infiltration and the thickening and narrowing of the pulmonary arterials. Results: Among 36 dogs, 2 dogs died within 24 hours after modeling, and 34 dogs were assigned to BAS+fenestrated ASD occulders group (n=12), BAS group (n=11), and non-septostomy group (n=11). Compared with BAS group, the average right atrial pressure (mRAP) and NT-proBNP of dogs in the BAS+fenestrated ASD occulders group were significantly reduced at 3 months after surgery (P<0.05), and the cardiac output (CO) was significantly increased at 6 months after surgery, arterial oxygen saturation (SaO₂) was also significantly reduced (P<0.05). Compared with non-septostomy group, dogs in the BAS+fenestrated ASD occulders group had significantly lower mRAP and NT-proBNP at 1, 3, and 6 months after surgery (P<0.05), and higher CO and lower SaO₂ at 6 months after surgery (P<0.05). Compared with the non-septostomy group, the dogs in the BAS group had significantly lower mRAP and NT-proBNP at 1 month after surgery (P<0.05), and there was no significant difference on mRAP and NT-proBNP at 3 and 6 months after surgery (P>0.05). Echocardiography showed that there was a minimal right-to-left shunt in the atrial septum in the BAS group at 1 month after the surgery, and the ostomy was closed in all the dogs in the BAS group at 3 months after the surgery. There was still a clear right-to-left shunt in the dogs of BAS+fenestrated ASD occulders group. The shunt was well formed and satisfactory endothelialization was observed at 1, 3 and 6 months after surgery. The results of HE staining showed that the pulmonary arterials were significantly thickened, stenosis and collapse occurred in the non-septostomy group. Pulmonary microvascular stenosis and inflammatory cell infiltration in the pulmonary arterials were observed in the non-septostomy group. Pulmonary arterial histological results were comparable between BAS+fenestrated ASD occulders group and non-septostomy group at 6 months after surgery. Conclusions: The fenestrated ASD occulder has the advantage of maintaining the open fistula hole for a longer time compared with simple balloon dilation. The fenestrated ASD occulder can improve cardiac function, and it is safe and feasible to treat PAH in this animal model.

[Impact of transcatheter aortic valve replacement on renal function in patients with severe aortic stenosis]

Objective: To explore the impact of transcatheter aortic valve replacement (TAVR) on renal function in patients with severe aortic stenosis. Methods: This is a single-center retrospective study. Consecutive patients with severe aortic valve stenosis and received TAVR in Zhongshan Hospital from December 2014 to December 2019 were included. The patients were divided into four groups according to the estimate glomerular filtration rate (eGFR) measured at one day before TAVR, namely eGFR>90 ml·min-1·1.73m-2 group, 6090 ml·min-1·1.73m-2 group, 60 Collapse

Key Words

• Acute kidney recovery
• Aortic valve stenosis
• Renal function
• Transcatheter aortic valve implantation

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[Effects of transcatheter aortic valve replacement in patients with severe aortic valve stenosis]

Objective: To investigate the effects of transcatheter aortic valve replacement (TAVR) in patients with severe aortic valve stenosis. Methods: The clinical data of 130 patients with severe aortic valve stenosis, who underwent TAVR in our hospital with self-expanding valve between January 1,2010 and October 30, 2016, were analyzed retrospectively. The patients were divided into calcific aortic valve stenosis (CAS) group (112 cases) and non-calcific aortic valve stenosis (NCAS) group (18 cases) according to 3D volume-rendering reconstruction under multiple detector computed tomography before TAVR. The baseline clinical features, imageology results, procedural details, and clinical prognosis were compared between the 2 groups. Results: (1) Compared with CAS group, the patients in NCAS group were younger, had higher proportion of rheumatic heart disease, and less proportion of bicuspid aortic valve morphology (P<0.01 or 0.05). Except for minimum value of sinotubular junction (P=0.017), there were no significant differences in multiple detector computed tomography measurements of aortic valve annulus and aortic root structure between the 2 groups (all P>0.05). (2) Compared with CAS group, the proportions of valve release under rapid pacing and oversized valve release were larger than pre-procedural evaluation, and the proportion of post-dilation was lower in NCAS group (P<0.01 or 0.05). (3) Post-procedural transthoracic echocardiography revealed that left ventricular ejection fraction was higher than baseline level in CAS group (P<0.001), while which was similar in NCAS group (P=0.552). Compared with before TAVR, mean pressure gradient and maximum transvalvular velocity were significantly reduced, aortic valve orifice area was significantly increased, and proportion of moderate to severe aortic regurgitation was significantly reduced after the procedure in both groups (all P<0.01). There were no significant differences in left ventricular ejection fraction, mean pressure gradient, maximum transvalvular velocity, aortic valve orifice area, and proportion of moderate to severe aortic regurgitation after TAVR between the 2 groups (all P>0.05). (4) There were no significant differences in successful rate of device placement and cardiovascular related death within 30 days after TAVR between the 2 groups (105/112 vs. 17/18, P=0.909; 3/112 vs. 1/18, P=0.453, respectively). Conclusion: TAVR is safe and effective for patients with severe aortic valve stenosis.

[Relationship of TLR2 and TLR4 expressions on the surface of peripheral blood mononuclear cells to small intestinal bacteria overgrowth in patients with hepatocellular carcinoma]

Objective: To investigate TLR2 and TLR4 expressional situation on the surface of peripheral blood mononuclear cells (PBMC) in patients with hepatocellular carcinoma (HCC) and their relationship with small intestinal bacterial overgrowth (SIBO). Methods: Flow cytometry was used to detect TLR2 and TLR4 expressional situation on the surface of PBMC in 78 cases with HCC, 56 cases with cirrhosis and 33 healthy controls. Furthermore, lactose hydrogen breath test (LHBT) was used to detect small intestinal bacterial overgrowth. Results: Of the 78 cases with HCC, 56 cases (71.8%) were SIBO-positive, 23 cases (41.1%) were SIBO- positive in 56 cases with cirrhosis, and 1 (3.0%) was SIBO-positive in 33 healthy controls. The incidence of SIBO in HCC patients was higher than cirrhosis patients (χ(2) = 12.72, P < 0.05) and healthy controls (χ(2) = 41.18, P < 0.05). The expression levels of TLR2 and TLR4 in HCC patients (100.55 ± 24.22, 42.76 ± 15.96) were significantly higher than cirrhosis (67.42 ± 18.36, 24.38 ± 8.68)and healthy control group (33.06 ± 11.72, 12.52 ± 4.46) (P < 0.05). Furthermore, the expression levels of TLR2 and TLR4 in SIBO-positive patients (108.75 ± 20.40, 48.1 ± 14.98) were higher than SIBO-negative patients (79.67 ± 20.60, 28.62 ± 7.36) (P < 0.05). Conclusion: The expression of TLR2 and TLR4 and the incidence of SIBO in HCC patients are significantly higher than cirrhosis and healthy control group. Moreover, the high expressions of TLR2 and TLR4 in SIBO-positive HCC patients may promote the development of HCC.

[Safety and efficacy of transcatheter aortic valve replacement through transcarotid approach for patients with severe aortic valve stenosis]

Objective: To investigate the safety and efficacy of transcatheter aortic valve replacement(TAVR) through transcarotid approach for patients with severe aortic valve stenosis. Methods: The clinical data of 9 symptomatic severe aortic valve stenosis patients who had high or prohibitive risk for surgery and not suitable for TAVR through femoral artery access,and thus received TAVR through transcarotid approach in our hospital from November 2015 to February 2017 were retrospectively analyzed.The patients were followed up to observe the safety and efficacy of the procedure. Results: There were 4 male and 5 female patients in this cohort, and age was (75.7±8.7) years old. The Society of Thoracic Surgery (STS) scores were (7.9±1.6)%. All patients were treated by left carotid artery approach. One patient experienced valve dislodgement during the procedure and received surgery, and TAVR procedure was successful in the rest 8 patients. Two patients were implanted with permanent pacemaker because of third degree atrioventricular block during the procedure.One patient had cardiac arrest during the procedure and recovered after external chest compression.One patient developed severe carotid stenosis,and there was no clinical manifestation of nerve function deficit after the procedure. All patients were followed up at (30±3) days after the procedure, and there were no adverse events. The modified Rankin scale score was 0. Echocardiography examination showed that the tranvalvular mean gradient was reduced from (63.0±19.2)mmHg(1 mmHg=0.133 kPa) on baseline to (18.1±4.9)mmHg(P<0.001), 4 cases had mild paravalvular leakage, and there was no moderate or severe paravalvular leakage.The NYHA classes was significantly improved at 30 days when compared with before the procedure(2 cases class Ⅱ, 4 cases class Ⅲ,3 cases class Ⅳ before the procedure,and 5 cases classⅠ, 4 cases class Ⅱ after the procedure, P=0.006) , and left ventricular ejection fraction increased from (55.9±13.1)% to (60.4±10.0)% (P=0.030). Conclusion: Our initial experience indicates that transcarotid TAVR is safe and effective for patients with severe aortic valve stenosis.

[Analysis of pulmonary valve function in patients with tetralogy of Fallot after radical surgery]

Objective: To analyze the pulmonary valve function in patients with tetralogy of Fallot after radical surgery. Methods: Clinical data of 263 patients (119 male, mean age (33.2±11.5) years old) with tetralogy of Fallot underwent radical surgery in our hospital from January 2010 to June 2016 were retrospectively analyzed. According to age, patients were divided into 14-17 years old group (14 cases), 18-29 years old group (100 cases), 30-39 years old group (61 cases) and above 40 years old group (87 cases). The patients were divided into pulmonary regurgitation group (87 cases) and control group (176 cases) according to weather they have moderate or severe pulmonary regurgitation. Echocardiographic data were compared among groups. Results: A total of 83 patients received re-operation. The median age of the primary radical operation was 9 (5, 13) years, and the median time from the primary radical operation to echocardiographic follow-up was 5 (1, 13) years. Among the 263 enrolled patients, prevalence of pulmonary regurgitation was 36.1% (95/263), and pulmonary stenosis was evidenced in 28 patients (10.6%). The ratio of moderate to severe tricuspid regurgitation was 14.3% (2/14), 27.0% (27/100), 32.8% (20/61) and 37.9% (33/87) in 14-17 years old group, 18-29 years old group, 30-39 years old group and above 40 years old group, respectively (P=0.029), while prevalence of moderate and severe pulmonary regurgitation, moderate and severe pulmonary valve stenosis, pulmonary valve transvalvular pressure >40 mmHg (1 mmHg=0.133 kPa), right atrial and right ventricular enlargement ratio were similar among groups (all P>0.05). The ratio of moderate and severe tricuspid regurgitation and right ventricular enlargement in the pulmonary regurgitation group was significantly higher than in the control group (40.2% (35/87) vs. 27.3% (48/176) and 96.6% (84/87) vs. 87.5% (154/176), all P<0.05), while left ventricular ejection fraction, right atrial enlargement, and right ventricular wall thickness were similar between the two groups (all P>0.05). Conclusion: Pulmonary regurgitation is a common clinical feature among survivors of tetralogy of Fallot patients after radical surgery, and moderate to severe pulmonary regurgitation increases the risk of tricuspid regurgitation and enlargement of the right ventricle.

The effect of alcohol on the differential expression of cluster of differentiation 14 gene, associated pathways, and genetic network

Alcohol consumption affects human health in part by compromising the immune system. In this study, we examined the expression of the Cd14 (cluster of differentiation 14) gene, which is involved in the immune system through a proinflammatory cascade. Expression was evaluated in BXD mice treated with saline or acute 1.8 g/kg i.p. ethanol (12.5% v/v). Hippocampal gene expression data were generated to examine differential expression and to perform systems genetics analyses. The Cd14 gene expression showed significant changes among the BXD strains after ethanol treatment, and eQTL mapping revealed that Cd14 is a cis-regulated gene. We also identified eighteen ethanol-related phenotypes correlated with Cd14 expression related to either ethanol responses or ethanol consumption. Pathway analysis was performed to identify possible biological pathways involved in the response to ethanol and Cd14. We also constructed a genetic network for Cd14 using the top 20 correlated genes and present several genes possibly involved in Cd14 and ethanol responses based on differential gene expression. In conclusion, we found Cd14, along with several other genes and pathways, to be involved in ethanol responses in the hippocampus, such as increased susceptibility to lipopolysaccharides and neuroinflammation.

[Risk factors of lung cancer complicated with symptomatic venous thromboembolism]

OBJECTIVE

To seek risk factors of VTE in patients with lung cancer through analysis of clinical features of patients with lung cancer complicated with venous thromboembolism (VTE).

METHODS

Retrospective investigation was performed on patients diagnosed with lung cancer and with complete clinical data who were hospitalized in Peking University People's Hospital from January 1, 2010 to December 31, 2014. According to the presence of symptomatic VTE, patients were distributed into two groups, VTE group and control group. Patients' clinical data and laboratory parameters were collected. Single factor analysis was applied to compare the differences between the two groups. t test or nonparametric test was applied for intragroup comparison of measurement data, and chi-square test was applied for the comparison of counting information. Logistic regression analysis was applied to explore risk factors of venous thromboembolism. For VTE patients with this diagnosis when they were hospitalized, D-dimer and PT were obtained after the occurrence of VTE, so D-dimer and PT were eliminated in the multiple factors analysis. SPSS 13.0 statistical software was applied for statistical management and analysis.

RESULTS

548 patients with lung cancer were include in the investigation, with male 357, female 191, average age of (63.8±10.9) years old, 46 patients in VTE group and 502 patinets in control group. According to the results of single factor analysis in gender, age, tumor pathologic type, tumor stage, WBC, Hb, PLT, CEA, ALT, FIB, D-dimer, PT, APTT, PT-INR, the tumor stage (χ(2)=14.177), CEA (t=2.129) and Hb (t=-2.424) were risk factors for lung cancer patients complicated with venous thromboembolism. Logistic regression analysis showed that tumor stage was the independent risk factor of lung cancer complicated with venous thromboembolism (OR 2.058, 95%CI 1.307-3.238, P=0.002) , and CEA (r=0.395, P<0.001) and Hb (r=-0.144, P=0.001) were associated with lung cancer stage. The area under the curve formed by D-dimer predicting VTE was 0.825 (95%CI 0.751-0.900, P<0.001).

CONCLUSION

Tumor stage is the only risk factor for lung cancer patients complicated with venous thromboembolism in the study. However, because this study is a retrospective study, other potential high risk factors causing VTE cannot be excluded.

Late gestational liver dysfunction and its impact on pregnancy outcomes

OBJECTIVE

The aim of this study was to investigate the impacts of late gestational liver dysfunction and its impact on pregnancy outcomes.

MATERIALS AND METHODS

The patients hospitalized for liver dysfunction in their late pregnancy between 2010-2012 were set as the observation group, and the pregnant women with normal liver function at the same period were randomly selected and set as the control group. The impacts towards the pregnancy outcomes were compared between these two groups and the impacts of different-degree transaminase increasing towards the pregnancy outcome were analyzed.

RESULTS

The incidence rates of cesarean section, post-partum hemorrhage, fetal distress, premature birth, premature rupture of membranes (PROM) of the observation group and the transaminase-severely-increased group (the severe group) were higher, and the differences were statistically significant (p < 0.01 or < 0.05); while only the cesarean rate of the mild and moderate group was significantly different from the control group (p < 0.01 or < 0.05). The ratios of intrahepatic cholestasis in pregnancy (ICP), gestational hypertension + HELLP syndrome, acute fatty liver in pregnancy (AFLP) of the severe group were higher than the mild and moderate group, and the differences were statistically significant; the non-alcoholic fatty liver disease (NAFLD) group and the unknown cause group mainly showed a mildly increased transaminase; the distributions of viral hepatitis in pregnancy (VHP), post-viral-hepatitis-B cirrhosis, biliary tract disease, and infected toxic liver dysfunction in different-degree increased transaminase groups had no significant difference.

CONCLUSIONS

Liver dysfunction in later pregnancy, especially with severe transaminase increase, might significantly increase the risk of adverse maternal events. The major causes of severe liver dysfunction in late pregnancy were ICP, gestational hypertensive disorders, and AFLP.

Organochlorine pesticide residuals in chickens and eggs at a poultry farm in Beijing, China

Chicken organs, animal feed, droppings, and ambient air were sampled at a farm in Beijing to determine the concentrations of hexachlorocyclohexane isomers (HCHs) and dichlorodiphenyltrichloroethane and metabolites (DDTs). Mean fresh weight concentrations of HCHs and DDTs were 0.122+/-0.061 ng/g and 0.051+/-0.038 ng/g in the muscles. These values are 1-2 orders of magnitude lower than those reported in China in 1980. Contaminated feed was the main source of HCHs and DDTs. Only 12.8% of HCH and 3.3% of DDT of the amount consumed were excreted. Accumulated quantities of HCHs and DDTs increased during growth. However, concentrations of HCHs and DDTs did not increase because of dilution from rapid growth. Based on the observed residual levels in mature chicken and the average diet of residents of China, the contributions from chicken and egg consumption to per capita daily intake of HCHs and DDTs were 487% and 88% of those of fish consumption.

A jasmonate-responsive element within the A. thaliana vsp1 promoter

The vsp1 gene of Arabidopsis thaliana encodes a storage protein that accumulates in vegetative organs. Transgenic plants expressing a vsp1 promoter-gus (beta-glucuronidase) gene fusion were found to contain high GUS activity when challenged with jasmonate, a volatile plant hormone. The induction of vsp1-gus expression by jasmonate could be measured in tobacco mesophyll protoplasts, after transient expression. A number of deletions were operated in the vsp1 promoter in order to locate its jasmonate-responsive element. A 41 bp sequence taken approximately 150 bp upstream of the vsp1 TATA box could confer jasmonate responsiveness upon a short CaMV 35S promoter. Whereas the deletion of a CAAT box-like element within the 41 bp sequence did not affect promoter activity, mutation of a short palindromic motif completely abolished jasmonate responsiveness. This motif shows no homology with the jasmonate-responsive elements of other promoters.

Ectopic expression of TATA box-binding protein induces shoot proliferation in Arabidopsis

The TATA box-binding protein (TBP) is an essential component of transcription initiation complexes of all three eukaryotic RNA polymerases. Increasing evidence suggests that the TBP activity and availability may be regulated to precisely control gene transcription and play an important role in cell type-specific regulation. Arabidopsis TBP-2 is up-regulated in apical shoot tissues. Overexpression of TBP-2 in transgenic Arabidopsis induces apical shoot proliferation. The expression of some shoot meristem regulatory genes is altered. These data suggest that the TBP gene dosage and/or expression level may play an important role in controlling shoot production and plant morphology.

Regulatory mechanism of plant gene transcription by GT-elements and GT-factors

GT-elements are regulatory DNA sequences ususally found in tandem repeats in the promoter region of many different plant genes. Depending on promoter structure, GT-elements can have a positive or a negative transcription function. The cognate GT-element binding factors contain one or two trihelix DNA binding motifs, which have so far been identified in plant transcription factors only. GT-factors are ubiquitously expressed; in Arabidopsis they belong to a small family of transcription factors. The functioning of plant GT-elements and GT-factors shows complex regulatory features of plant gene transcription.

Transcriptional activation by Arabidopsis GT-1 may be through interaction with TFIIA-TBP-TATA complex

GT-1 belongs to the class of trihelix DNA-binding proteins and binds to a promoter sequence found in many different genes. Data presented in this report show that GT-1 contains a trans-activation function in yeast and in plant cells. However, in tobacco BY-2 protoplasts, this activity functions only when an internal region containing the DNA-binding domain is deleted. Gel-shift and co-immunoprecipitation assays have revealed that GT-1 can interact with and stabilize the TFIIA-TBP-TATA complex. These results suggest that GT-1 may activate transcription through direct inter- action with the transcriptional pre-initiation complex.

Characterization and functional analysis of Arabidopsis TFIIA reveal that the evolutionarily unconserved region of the large subunit has a transcription activation domain

TFIIA has initially been identified as a component of transcription initiation complex of RNA polymerase II. Its role in transcription has been controversial. In this paper, we report the characterization and functional analysis of both the Arabidopsis TFIIA large and small subunits. Sequence analysis revealed that Arabidopsis TFIIA is structurally more related to animal than to yeast counterparts. Arabidopsis has at least two genes for the large subunit and one for the small subunit. Both types of genes are constitutively transcribed in various plant organs. The proteins encoded by the cDNA interact each other in yeast 2-hybrid system. Only the N-terminal part of the large subunit is necessary for the interaction with the small subunit. Recombinant Arabidopsis TFIIA polypeptides bind to TBP-DNA complex in gel shift assays. The large subunit of TFIIA can stimulate transcription in yeast and in plant cells when fused to a DNA-binding domain binding to cis sequences upstream of a minimal promoter. This trans-activating activity is localized to a 35 amino acid segment within the evolutionarily unconserved central region.

COP1b, an isoform of COP1 generated by alternative splicing, has a negative effect on COP1 function in regulating light-dependent seedling development in Arabidopsis

COP1 is a negative regulator of Arabidopsis light-dependent development. Mutation of the COP1 locus causes constitutive photomorphogenesis in the dark. Here, we report the identification of an isoform of the COP1 protein, named COP1b, which is generated by alternative splicing. COP1b has a 60-amino acid deletion in the WD-40 repeat domain relative to the full-length COP1. This splicing step is light-independent and takes place mostly in mature seeds and in germinating seedlings. Transgenic Arabidopsis plants that overexpress COP1b show a de-etiolated phenotype in the dark, with a short hypocotyl, open and developed cotyledons. The transgenic seedlings are adult-lethal. These phenotypes closely resemble that of severe cop-1 mutants, indicating that COP1b has a dominant negative effect on COP1 function.

The mechanism of GT element-mediated cell type-specific transcriptional control

Promoter studies have revealed that sequences related to the GT-1 binding site, known as GT elements, are conserved in plant nuclear genes of diverse functions. In this work, we addressed the issue of whether GT elements are involved in cell type-specific transcriptional regulation. We found that the inactivation of GT-1 site-mediated transcription in roots is correlated with the absence of the GT-1 binding activity in root extracts. In addition, the mutation of the related GT-1 (from the pea rbcs-3A) and the S1F (from the spinach rps1) sites resulted in an increase of their transcriptional activity in roots that contain a distinct GT element-binding factor, referred to as RGTF. Although specific to GT elements, RGTF has a different sequence requirement and a lower sequence specificity than GT-1. Interestingly, RGTF has a higher binding affinity to the mutant GT-1 and S1F sites than to the wild-type sequences. This correlation suggests that RGTF may have some role in transcriptional regulation in roots. Furthermore, root cellular protein extracts contain an inhibitory activity that prevents GT-1 from binding to DNA. This helps to explain the absence of the GT-1 binding activity in roots in which the gene of GT-1 is expressed. Together, these data suggest that the cell type-specific transcription modulation by GT elements is achieved by using two different strategies.

Cis-acting elements and expression pattern of the spinach rps22 gene coding for a plastid-specific ribosomal protein

In order to study the regulation of nuclear genes coding for plastid ribosomal proteins, we have analysed the promoter region of spinach rps22 using both in vitro and in vivo approaches. By footprinting analyses, we have identified eight DNA elements interacting with spinach leaf nuclear factors in the 300 bp promoter region upstream of the transcription start site. Among these elements, four are short AT-rich sequences and one is identical to the Hex motif characterized initially in wheat histone genes. In transgenic tobacco plants, the reporter gene coding for the beta-glucuronidase (GUS) directed by a 1.2 kb upstream region of rps22 was expressed in several plant organs, with high levels in leaf mesophyll, embryo cotyledons and root meristematic cells and very low levels in other cell types. Interestingly, when deleted to -295, the promoter, which contained all the foot-printed elements, was still able to confer the same expression pattern, although the activity was relatively lower than with the 1.2 kb promoter. When deleted further to -154, the promoter, from which the AT-rich elements were eliminated, loses its activity almost completely, suggesting that these AT-rich elements are important for the rps22 promoter activity. Altogether, our results show that rps22 gene expression is controlled by specific cis elements not present in other nuclear-encoded plastid ribosomal protein genes studied so far.

Molecular cloning of a small DNA binding protein with specificity for a tissue-specific negative element within the rps1 promoter

A cDNA encoding a specific binding activity for the tissue-specific negative cis-element S1F binding site of spinach rps1 was isolated from a spinach cDNA expression library. This cDNA of 0.7 kb encodes an unusual small peptide of only 70 amino acids, with a basic domain which contains a nuclear localization signal and a putative DNA binding helix. This protein, named S1Fa, is highly conserved between dicotyledonous and monocotyledonous plants and may represent a novel class of DNA binding proteins. The corresponding mRNA is accumulated more in roots and in etiolated seedlings than in green leaves. This expression pattern is correlated with the tissue-specific function of the S1F binding site which represses the rps1 promoter preferentially in roots and in etiolated plants.

S1F binding site is related to but different from the light-responsive GT-1 binding site and differentially represses the spinach rps1 promoter in transgenic tobacco

Nuclear genes encoding plastid ribosomal proteins are more highly expressed in leaves than in roots. This leaf-specific induction seems to be light-independent. We have previously characterized a spinach nuclear factor S1F binding to a cis-element within the rps1 promoter, which negatively regulates both the rps1 and the cauliflower mosaic virus 35S promoters in transient expression assays. Here, we show that the S1F binding site is related to but different from the light-responsive Box II of the pea rbcS-3A promoter, which is recognized by the nuclear factor GT-1. Transgenic plant analyses showed that the S1F site tissue-specifically represses the rps1 promoter in roots as well as in etiolated seedlings. We suggest that the GT-1-related S1F binding site is responsible, at least in part, for the transcriptional repression of rps1 in nonphotosynthetic tissues such as roots.

[Investigation of chronic arsenic poisoning caused by high arsenic coal pollution]

This article reports the results of an investigation on environmental arsenic pollution and chronic arsenic poisoning in a rural area. Exploitation of high arsenic coal caused drinking and irrigating water to be polluted by arsenic and burning of this coal caused severe environmental arsenic pollution including air, food, soil and drinking well water. 1548 villagers in 47 villages suffered from chronic arsenic poisoning who used this coal in daily life. The polluted air and food were mainly responsible, while the polluted drinking water and skin absorption played some part in poisoning. When arsenic level in coal is as high as 100mg/kg, we should consider the possibility of environmental arsenic pollution and chronic arsenic poisoning in exposed population. The high arsenic coal's distribution is very uneven. When controlling the disease, it is important to remember monitoring the quantity of arsenic coal outside the arsenic coal mining area.

Sequence-specific interaction between S1F, a spinach nuclear factor, and a negative cis-element conserved in plastid-related genes

The nuclear gene rps1 coding for the spinach plastid ribosomal protein CS1 exhibits both a constitutive and leaf-specific expression pattern. In contrast to other chloroplast-related genes like rbcS and cab, the leaf induction of rps1 expression is light-independent. These unique features of rps1 expression provide good models to study the mechanisms regulating plastid development and differentiation in higher plants. We report on the identification of a spinach leaf nuclear factor, designated S1F, interacting with the rps1 promoter. The S1F binding site is conserved in the promoter region of many plastid-related genes, including rbcS, cab, and rpl21. A binding activity similar to S1F was detected in nuclear extract from dark-grown de-differentiated soybean suspension cells. Through site-specific mutagenesis and transient expression in soybean cell protoplasts, we show that the S1F binding site is a negative element down-regulating the promoter activity of rps1. A ligated tetramer of S1F site was able to repress activity of the cauliflower mosaic virus 35 S promoter extending the negative function of the S1F binding site on promoter activity.

Structure and expression of the nuclear gene coding for the plastid CS1 ribosomal protein from spinach

The chloroplast ribosomal protein CS1 is an essential component of the plastids translational machinery involved in translation initiation. Southern analysis suggests that the corresponding nuclear gene is present in one copy in the spinach genome. We have isolated and sequenced the gene (rps1) to study its expression at the transcriptional level. The gene consists of 7 exons and 6 introns including an unusually large intron in the 5' coding region. No canonical TATA-box is found in the 5' upstream region of the gene. rps1 transcripts are detected early during germination and a significant accumulation is observed after the protrusion of the radicle. CS1 mRNAs are present in all organs of young seedlings although there are dramatic differences in the steady state level of the mRNAs between leaves and roots tissues. Transcripts accumulate independently of the presence or absence of light. Band shift analysis shows that the +1, -400 bp region of the gene can bind different sets of proteins isolated from roots and leaves nuclei. We suggest that the expression of the housekeeping plastid-related rps1 gene is regulated in a tissue-specific manner by transcriptional trans-acting factors.

The hepatitis B virus S promoter comprises A CCAAT motif and two initiation regions

The hepatitis B virus S (major surface gene) promoter is embedded in two overlapping open reading frames and specifies several transcripts with heterogeneous 5' termini. We have identified the cis-elements necessary for S promoter function. A single upstream CCAAT element is essential for high level expression in both liver and non-liver cells. No TATA box is present, but two regions surrounding the initiation sites can function separately as initiating elements. These results show that the S promoter has a simple requirement for upstream activating sequences, but a complex initiation region. Therefore, it may provide a suitable model system for studying transcription initiation in non-TATA type promoters.

Differential regulation of the hepatitis B virus surface gene promoters by a second viral enhancer

The hepatitis B virus surface gene is transcribed from two promoters, and the resulting mRNA species code for three distinct forms of the surface antigen. We show here that the viral transcriptional trans-activator, X protein, has no effect on either promoter. However, a cis-acting element in the downstream half of the X gene, distinct from the previously mapped viral enhancer, selectively activates the major surface gene promoter. Nuclease protection and gel-shift assays reveal that multiple cellular factors bind to two sites within this DNA fragment, both of which are necessary for enhancer activity. Since this region of the viral genome is frequently deleted upon integration into the hsot chromosome in chronic hepatitis B, loss of this second enhancer can alter the relative amounts of the three forms of the surface antigen in infected hepatocytes and thus possibly contribute to cellular damage.

Activation of class I major histocompatibility complex gene expression by hepatitis B virus

Normal hepatocytes express very few class I major histocompatibility complex (MHC I) molecules, but MHC I expression is elevated in hepatitis B virus (HBV) infection. We report here that hepatoblastoma cells with replicating HBV genomes express three- to fourfold-higher levels of MHC I protein and mRNA than do parent cells without HBV DNA. Transient transfection assays demonstrated that the HBV X protein trans activated transcription from an MHC I promoter and allowed identification of cis elements important for trans activation.

trans-activation by the hepatitis B virus X protein shows cell-type specificity

The hepatitis B virus X protein can trans-activate transcription from many viral promoters. We show here that this trans-activation is cell-type but not species specific, and that only a subset of promoters is trans-activated in any particular cell type. Furthermore, the T/t-antigens from simian virus 40 suppress this trans-activation. We hypothesize that the X protein acts via cellular factors which are phylogenetically conserved and developmentally regulated and whose effects are blocked by the T/t-antigens.

Presence in the stroma of chloroplasts of a large pool of a ribosomal protein not structurally related to any Escherichia coli ribosomal protein

A search was made for the presence of a pool of free ribosomal proteins in the stroma of the spinach chloroplast. The results showed that a relatively large amount of one protein, CS-S5, is present in the stroma. Immunoprecipitation experiments showed that this protein is encoded by the nuclear genome. Clones were isolated from a cDNA library constructed in the expression vector lambda gt11, using specific antibodies raised against the CS-S5 protein. A full-length cDNA was sequenced which contains an open reading frame (ORF) for the precursor of the CS-S5 protein, as shown by immunoprecipitation. This precursor contains a putative transit peptide of 66 amino acids and the mature product has no significant homology with any of the Escherichia coli ribosomal proteins, in contrast to the other ribosomal protein gene products so far identified in spinach chloroplasts.

Cotranscription of the S10- and spc-like operons in spinach chloroplasts and identification of three of their gene products

The organisation and expression of the rpl22, rps3, rpl16 and rpl14 genes, which belong to the S10- and spc-like operons of spinach chloroplasts, have been studied. Northern experiments and nuclease S1 mapping show that the two operon-like groups of genes are cotranscribed. It is demonstrated that the intron-containing rpl16 gene is spliced in vivo. Based on amino acid composition and protein sequence data, the products of the rpl22, rpl16 and rpl14 genes are identified respectively as the spinach chloroplast ribosomal proteins CS-L13, CS-L24 and CS-L29. The rpl22 gene product is a 5S rRNA binding protein and therefore is distinguishable from the homologous Escherichia coli L22 ribosomal protein.

Characterization of a large inversion in the spinach chloroplast genome relative to Marchantia: a possible transposon-mediated origin

A 7,022 bp BamHI-EcoRI fragment, located in the inverted repeat of spinach chloroplast, has been sequenced. It contains a 2131 codon open reading frame (ORF) homologous to both tobacco ORFs 581 and 1708, and to Marchantia ORF 2136. Relative to the Marchantia chloroplast genome, spinach ORF 2131 is located at the end of a large inversion; the other end point is close to trnL, the position of which is the same in Marchantia, tobacco and spinach. In Marchantia, two 8 bp direct repeats flanking two 10 bp indirect repeats are present near the end points of the inversion. These repeats may result from a transposon-mediated insertion which would have facilitated the subsequent inversion. From a comparison of the gene organization of the spinach, tobacco, and Marchantia genomes in this region, we propose a step-wise process to explain the expansion of the inverted repeat from a Marchantia-like genome to the spinach/tobacco genome.