Increased yield of 2-O-α-d-glucopyranosyl-l-ascorbic acid synthesis by α-glucosidase using rational design that regulating the ground state of enzyme and substrate complex

BACKGROUND

α-Glucosidase (AG) is a bifunctional enzyme, it has a capacity to synthesize 2-O-α-d-glucopyranosyl-l-ascorbic acid (AA-2G) from l-ascorbic acid (L-AA) and low-cost maltose under mild conditions, but it can also hydrolyze AA-2G, which leads to low synthesis efficiency of AA-2G.

MAIN METHODS AND MAJOR RESULTS

This study introduces a rational molecular design strategy to regulate enzymatic reactions based on inhibiting the formation of ground state of enzyme-substrate complex. Y215 was analyzed as the key amino acid site affecting the affinity of AG to AA-2G and L-AA. For the purpose of reducing the hydrolysis efficiency of AA-2G, the mutant Y215W was obtained by analyzing the molecular docking binding energy and hydrogen bond formation between AG and the substrates. Compared with the wild-type, isothermal titration calorimetry (ITC) results showed that the equilibrium dissociation constant (KD ) of the mutant for AA-2G was doubled; the Michaelis constant (Km ) for AA-2G was reduced by 1.15 times; and the yield of synthetic AA-2G was increased by 39%.

CONCLUSIONS AND IMPLICATIONS

Our work also provides a new reference strategy for the molecular modification of multifunctional enzymes and other enzymes in cascade reactions system.

A four oxidative stress gene prognostic model and integrated immunity-analysis in pancreatic adenocarcinoma

Background and aims

Pancreatic adenocarcinoma (PAAD) is highly aggressive and characterized by a poor prognosis. Oxidative stress has great impacts on the occurrence and development of tumors. However, the predictive role of oxidative stress related genes on PAAD patients' prognosis remains unclear. In this study, we aimed to construct a prognostic model for PAAD based on oxidative stress genes and to evaluate its predictive value.

Methods

The Cancer Genome Atlas (TCGA) and three Gene Expression Omnibus (GEO) datasets were used to identify differentially expressed oxidative stress genes. Univariate Cox regression, Kaplan-Meier and multivariate Cox regression analysis were used to select genes and to construct a prognosis model. According to the median value of the model's risk score, patients were divided into high and low risk groups, and gene set enrichment analysis (GSEA), immune infiltration and immunotherapy effect, drug resistance and the expression of immune checkpoint related genes and synthetic driver genes of T cell proliferation were analyzed. Finally, the mRNA and protein levels of four genes in PAAD were verified by the clinical proteomic tumor analysis consortium (CPTAC) database and the immunostaining of patients' tissue.

Results

55 differentially expressed oxidative stress genes were identified, and four genes including MET, FYN, CTTN and CDK1 were selected to construct a prognosis model. GESA indicated that immune related pathways, metabolic pathways and DNA repair pathways were significantly enriched in the high risk group as compared to the low risk group. The frequency of genetic mutations was also significantly higher in high risk groups than that in low risk groups. Moreover, the infiltration level of 23 immune cells as well as the expression of immune checkpoint related and synthetic driver genes of T cell proliferation were significantly altered, with the better immunotherapy effect occurring in low risk group. In patient PAAD tissues, the mRNA and protein levels of these four genes were up-regulated.

Conclusion

We have successfully constructed a four oxidative stress gene prognostic model that has important predictive value for PAAD patients, and this model might be a promising guidance for prognostic prediction and efficacy monitoring in clinical individualized therapy.

[Expression of METTL14 in epithelial ovarian cancer and the effect on cell proliferation, invasion and migration of A2780 and SKOV3 cells]

Objective: To study the expression of methyltransferase-like protein 14 (METTL14) in epithelial ovarian cancer and its clinical significance, and to explore the effect of METTL14 expression on the proliferation, invasion and migration of ovarian cancer cells. Methods: Immunohistochemistry (IHC) was used to detect METTL14 expression in tumor tissue samples, and analyze the relationships among METTL14 expression, clinicopathological factors, and prognosis in ovarian cancer. Lentiviral vectors and small interfering RNA (siRNA) were used to up-regulate and down-regulate the METTL14 expression in ovarian cancer cell lines A2780 and SKOV3, respectively. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was used to detect the N6-methyladenosine (m6A) content in ovarian cancer cells. Cell counting kit-8 (CCK-8), wound healing assay, and transwell assay were used to examine the function of METTL14 expression in the cells. Results: (1) The IHC score of METTL14 protein was 6.2±3.7 in 20 samples of ovarian cancer tissues and 3.3±2.5 in 15 samples of normal ovarian tissues, and the difference was statistically significant (t=-2.64, P=0.012). Among the patients who suffered from ovarian cancer, there were 69 cases with high expression of METTL14 protein (IHC score≥6), accounting for 57.0% (69/121), and the cases with low expression of METTL14 protein (IHC score<6) accounting for 43.0% (52/121). Compared with the patients with low expression of METTL14, the patients with high expression of METTL14 had later stages, higher rates of lymph node metastasis, abdominal metastasis, and more ascite amount. The differences were statistically significant (all P<0.05). The overall survival rate was significantly lower in patients with high METTL14 expression than the low expression (P=0.009). (2) LC-MS/MS data showed that the relative expression of m6A in A2780 and SKOV3 cells in the lentivirus (LV)-METTL14 group were 0.213±0.024 and 0.181±0.018, which were significantly higher than those in the LV-normal control (NC) group (0.109±0.022 and 0.128±0.020; all P<0.05). While the relative expression of m6A in A2780 and SKOV3 cells in the si-METTL14 group were 0.063±0.012 and 0.069±0.015, which were significantly lower than the expression in si-NC group of 0.108±0.014 and 0.121±0.014 (all P<0.05). CCK-8 assay showed that the absorbance values were significantly lower in the si-METTL14 group compared with the si-NC group at 36, 48, 60 hours (all P<0.05); while were significantly increased in the LV-METTL14 group compared with the LV-NC group at 48, 60 hours (all P<0.01). Scratch wound assays showed that the migration rate of the si-METTL14 group was lower than those of the si-NC group, while the LV-METTL14 group were higher than the LV-NC group by 24 hours, the differences were statistically significant (all P<0.01). Cell migration and invasion were detected by transwell migration and invasion assays. After cultivated for 24 hours, the invasion cell number and the migration cell number in the si-METTL14 group were less than those in the si-NC group. While the invasion cell number and the migration cell number in the LV-METTL14 group were more than those in the LV-NC group, respectively. The differences were statistically significant (all P<0.01). Conclusion: Patients with high METTL14 expression have a worse prognosis in ovarian cancer, which may increase the m6A modification of ovarian cancer cells and promote cells proliferation, invasion and migration.

Near-infrared reflectance spectroscopy-based fast versicolorin A detection in maize for early aflatoxin warning and safety sorting

Aflatoxins (AFs) are potent carcinogens present in numerous crops. Access to accurate methods for evaluating contamination is a critical factor in aflatoxin risk assessment. Versicolorin A (Ver A), a precursor of aflatoxin B₁ (AFB₁), can be used as an indicator for the presence of AFB₁, even when the AF is not yet detectable. Currently employed Ver A detection methods are expensive, time consuming, and difficult to apply to numerous samples. Herein, Ver A was detected via near-infrared spectroscopy. Both quantitative and two-grade sorting methods were set-up using the extreme gradient boosting algorithm coupled with a support vector machine. This two-tiered method obtained a root-mean-square error of prediction value of 3.57 μg/kg for the quantitative model, and an accuracy rate of 90.32% for the sorting approach. This novel method is rapid, accurate, solvent free, requires no sample pretreatment, and detects Ver A in maize, making it convenient for practical use.

[Lentivirus media miR-1246 knockdown inhibits tumor growth and promotes apoptosis of SiHa cells]

Objective: To study the effect of lentivirus-mediated microRNA (miR) -1246 RNA interference (RNAi) on biological characteristics and behaviors in cervical cancer cells as well as to identify the downstream signaling pathways affected. Methods: MiR-1246 specific cDNA was synthesized and cloned into the recombinant lentiviral vector (LV-miR-1246-inhibitor) . The SiHa cells were devided into three groups: no viral infection (negative control, NC) , infection with control virus (LV-NC) , and infection with miR-1246-inhibitor virus (LV-miR-1246-inhibitor) . The expression of the miR-1246 was detected by reverse transcription (RT) -PCR. Cell growth was analyzed by cell counting kit 8 (CCK-8) assay. The invasion was dectected by transwell matrige gel. Cell apoptosis was detected by flow cytometer. The growth of xenograft tumors was also investigated. Expression of thrombospondin-2 (THBS2) , matrix metalloproteinase (MMP) 2, 9 were also evaluated in the cells. Results: (1) The expression level of miR-1246 in SiHa cells (0.11±0.13) was significantly lower in group LV-miR-1246-inhibitor than those in the group LV-NC and the group NC (1.14±0.86 and 1.30±0.73, respectively; P<0.01) . (2) The proliferation of SiHa was also markedly suppressed in CCK-8 at 96 hours (P<0.01) . (3) The number of group LV-miR-1246-inhibitor was significantly less than those in the LV-NC and NC groups in transwell invasion assay (71±4, 162±5 and 188±5, respectively; P<0.01) . (4) The apoptosis rate of SiHa cells in the group LV-miR-1246-inhibitor [ (16.10±3.37) %] was significantly lower than those of group LV-NC and group NC [ (5.67±0.89) % and (1.78±0.08) %,P<0.01]. (5) The tumor volume in the nude mice group LV-miR-1246-inhibitor [ (287±59) mm(3)] was significantly lower than those in the LV-NC and NC groups [ (571±137) and (657±144) mm(3), respectively; P<0.01]. (6) Compared with the LV-NC group and the NC group, THBS2 protein expression in the tumor tissue of the nude mice in the group LV-miR-1246-inhibitor was significantly increased (P<0.05) , while the expression levels of MMP-2 and MMP-9 protein were significantly decreased (P<0.01) . Conclusion: These results suggest that miR-1246 functions during cervical cancer pathogenesis and tumor formation via the THBS2, MMP signaling pathway.

Versicolorin A is a potential indicator of aflatoxin contamination in the granary-stored corn

The objective of this study was to evaluate the feasibility of the predictive monitoring of aflatoxin B₁ (AFB₁) under granary conditions, since mycotoxin contamination of the stored grain represents an important issue. Using the storage test, we investigated the relationship between versicolorin A (Ver A, an intermediate in AFB₁ biosynthesis) levels and the levels of aflatoxigenic fungi, and their relationship with aflatoxin production. All samples, except for one, were found to be contaminated with aflatoxigenic fungi using PCR analyses, while their AFB₁ levels were not detectable before the storage test using an enzyme-linked immunosorbent assay (ELISA) method with an LOD of 2 μg/kg. Aflatoxigenic fungi levels were analysed, as well as Ver A levels prior to the accumulation of AFB₁ (Levels were ≥5 μg/kg; the permissible levels of AFB₁ in corn intended for direct consumption are <5 μg/kg (EC)). Statistical analyses demonstrated that aflatoxin levels after both actual storage and safe storage (AFB₁˂5μg/kg) times are significantly correlated with the Ver A levels and the changes in Ver A levels (ΔVer A). Both high and variable Ver A levels were indicative of the vigorous metabolic activity of aflatoxigenic fungi. In contrast, steady Ver A levels showed that aflatoxin production by the fungi was not active. Monitoring Ver A levels and their changes may allow an earlier detection of harmful aflatoxin contamination in the stored grain. Additionally, the toxicity of Ver A should be further examined. The results of our study indicate that the monitoring of Ver A levels, even when the AFB₁ levels are very low, may increase the safety of grain consumption, especially considering Ver A toxicity.

Berberine prevents the apoptosis of mouse podocytes induced by TRAF5 overexpression by suppressing NF-κB activation

Berberine (BBR) has previously been found to exert beneficial effects on renal injury in experimental rats. However, the mechanisms underlying these effects are not yet fully understood. Tumor necrosis factor (TNF) receptor-associated factor 5 (TRAF5) has been demonstrated to mediate the activation of nuclear factor-κB (NF-κB), which has been implicated in the pathogenesis of chronic kidney disease (CKD). The aim of this study was to investigate the effects of BBR on kidney injury and the activation of the NF-κB signaling pathway in mouse podocytes. TRAF5 was found to be overexpressed in patients with CKD and chronic renal failure (CRF) (data obtained from the dataset GSE48944, as well as from patients at Shuguang Hospital). TRAF5 overexpression significantly inhibited cell viability and induced the apoptosis of mouse podocytes. However, BBR prevented the decrease in cell viability and the apoptosis induced by TRAF5 overexpression. The NF-κB inhibitor, caffeic acid phenethyl ester (CAPE), mimicked the protective effects of BBR, as evidenced by the increased expression of nephrin and podocin, and the decreased the expression of caspase-3 and the ratio of Bax/Bcl-2. Moreover, BBR prevented the decrease in cell viability decrease and the apoptosis induced by TNF-α, interleukin (IL)-6 and lipopolysaccharide (LPS). Taken together, our data indicate that BBR exerts protective effects against CRF partly through the TRAF5-mediated activation of the NF-κB signaling pathway in mouse podocytes.

[Comparison of the short-term and long-term outcomes of laparoscopic surgery and open surgery for early-stage cervical cancer]

Objective: To evaluate the short-term and long-term outcomes after laparoscopic surgery compared with traditional laparotomy in cases of stage ⅠA2-ⅡA2 cervical cancer. Methods: We conducted a retrospective study on the clinical data of 1 863 patients diagnosed as FIGO stages ⅠA2-ⅡA2 cervical cancer in 6 third-grade class-A hospitals in Guangxi province between January 2007 and May 2014. One thousand and seventy-one received laparoscopy, and 792 received laparotomy. T-test, U-test and χ(2) test were used to compare the short-term and long-term outcomes. The short-term outcomes included surgical related outcomes and operative complications, and the long-term outcomes included quality of life (pelvic floor functions and sexual functions), survival and recurrence. Pelvic floor function and sexual function were assessed with the International Consultation on Incontinence Quesonnaire Female Lower Urinary tract(ICIQ-FLUTS) and the Female Sexual Function Inventory (FSFI), respectively. Survival rates were estimated by Kaplan-Meier analysis. The survival curves were compared with Log-rank test. Cox regression analysis was used to evaluaterisk factors for prognosis. Results: (1)The short-term outcomes : There were significant difference in operative time([(257±69) vs(238±56)min], estimated blood loss[(358±314) vs(707±431)ml], anus exhausting time[(2.5±0.9) vs (2.9±0.8)d], preserved days of catheter[(15±7) vs(18±9)d], and post-operative length of stay[(19±16) vs (30±21)d] between the laparoscopic surgery group and the opensurgery group(P<0.05). There was no significant difference in lymph nodes yielded[(21±9) vs (21±11)], left parametrial width[(2.5±0.8) vs (2.7±0.7)cm], right parametrial width [(2.6±0.3) vs (2.7±0.2)cm], vaginal cuff length[(2.4±0.7) vs (2.2±0.7)cm] between the laparoscopic surgery group and the opensurgery group(P>0.05). The intra-operative complications occurred in 8.1%(87/1 071)in the laparoscopic surgery group and in 10.7%(85/792)in the open surgery group(P>0.05). However, the complications of vascular injury in the laparoscopic surgery group[2.6%(28/1 071)]was lower than that in the open surgery group[7.7%(61/792), P<0.001]. The laparoscopic surgery exhibited lower post- operative complication rate [33.8%(362/1 071)vs 40.2%(318/792), P<0.05] and poorer wound healing rate [0.7%(7/1 071)vs 4.0%(32/792), P<0.05]. (2)The long-term outcomes(Hierarchical analysis): The overall incontinence in ICIQ-FLUTS questionnaire in nerve-sparing laparoscopic group [28.4%(67/236)] was lower than that in the open surgery group [35.9%(71/198), P=0.004] . However, There was no significant difference in degree of incontinence between the two groups(P>0.05). The overall sexual dysfunction in FSFI questionnaire after 12 months of postoperative in the nerve-sparing laparoscopic group [47.0%(111/236)]was lower than that in the open surgery group [58.6%(116/198), P=0.001], and the six different dimension scores in the laparoscopic surgery group were higher than that in the open surgery group (P<0.05). The recurrence rate was 3.5%(35/1 007)in the laparoscopicsurgery group and 4.7%(35/740)in the open surgery group(P>0.05). The 5-year OS was 94.0% for the laparoscopic surgery group and 90.2% for the open surgery group(P>0.05), and the 5-year DFS was 93.9% for the laparoscopic surgery group and 89.1% for the open surgery group(P>0.05). (3) Prognostic fators: In univariate analysis, tumor dimension, clinical stage, deep stromal invasion, LVSI, and retroperitoneal lymph node metastasis signficantly affected 5-year OS and 5-year DFS(P<0.05); In multivariate analyses, LVSI, deep stromal invasion and LN metastasis were independent prognostic factors(P<0.05). Conclusions: Laparoscopy can reduceestimated blood loss, accelerate postoperative recovery and improve the quality of life after surgery compared to laparotomy, and it ensures the same oncological results as open surgery. Laparoscopic approach is a safe and effective treatment for early-stage cervical cancer.

A novel biosensor for sterigmatocystin constructed by multi-walled carbon nanotubes (MWNT) modified with aflatoxin–detoxifizyme (ADTZ)

Sterigmatocystin, ST, is carcinogenic mycotoxin with toxicity second to aflatoxins, contaminated in foods- and feeds-stuff widely. A three-electrode system was employed to examine the response character of the covalently united ADTZ-MWNTs electrode to ST, and the results indicated that an oxidation peak of ST was observed at about +400 mv, the linear detection range of ST was from 4.16 x 10(-5) mg/ml (0.13 microM) to 1.33 x 10(-3) mg/ml (4.29 microM) with the detection limit at 0.13 microM. Compared to the corresponding results obtained from the MWNTs modified electrode that ADTZ was directly sediment (adsorbed) on it, the sensitivity of ours had been improved by two orders of magnitude, which could provide some important data to further research.

[The primary study on the detection of sterigmatocystin by biologic enzyme electrode modified with the multiwall carbon nanotubes]

Sterigmatocystin (ST), the secondary metabolite of many kinds of filamentous fungi, is a potent carcinogen structurally related to the aflatoxins (AFT). With similar chemical structure, sterigmatocystion behaves much the homogeneous properties to aflatoxins, both of these mycotoxins exhibit similar biological properties due to their bisfuranoid structure. Since the common, and even heavier pollution, found in foods and feeds-stuff, sterigmatocystion is more harmful than aflatoxins. The reported detection methods of sterigmatocystion included the Thin-layer Chromatography, the High-Performance-Liquid Chromatography, the Enzyme-Linked Immunosorbant Assay and the PCR detection to the toxic gene, however studies about both easy and inexpensive electro-chemical methods have not been found. Our previous studies had discovered that Sterigmatocystin (ST) exist similar sensitivity towards aflatoxin-detoxifizyme (ADTZ), which we had isolated from a fungus, as aflatoxin does. In this work, the preliminary study on electrochemical analysis and determination of ST with triplet electrode enzyme-biosensor system (Ag/AgCl as the reference electrode, Pt and Au as the pair and work electrode, respectively) was carried out. Multiwall-carbon-nanotube (MWNT) had been used to increase the electron transportation on electrode. In the research, the Au electrode was modified by MWNT-immobilized ADTZ, and then the voltammertric behavior of ST was studied by means of cyclic voltammogram analysis and different pulse analysis. Autoprobe CP Research Atomic Force Microscope and TECNAI 10 Transmission Electron Microscope, had been used to detect the MWNT as well as the surface of MWNT-modified ADTZ. The voltammertric behavior of ST was studied by means of cyclic voltammogram analysis and different pulse analysis. The results show that the red-ox peak potential of ST is at the point of -600 mV, the linear detection range is from 8.32 x 10(-5) to 66.56 x 10(-5) mg/mL, the detection limit is at 8.32 x 10(-5) mg/mL, and the response time is 10 seconds. This study provided a good basic work for further research.

[Characterization of immobilized aflatoxin-detoxizyme]

Aflatoxins, found in contaminated food, are potent hepatocarcinogen. The aflatoxin-detoxiczyme (ADTZ) isolated from the edible fungus Armillariella sp., detoxifies aflatoxin B1 (AFB1). This paper reports on the characterization of immobilized ADTZ using a hydrophobic adsorption method. The ADTZ was isolated from cryo-homogenated fungus, previously cultivated at 24 - 28 degrees C for 20 - 30 days, using n-alkyl amino-agar beads. Various adsorption conditions of the enzyme to n-alkyl or n-octyl amino-agar beads were carried out. The effects of enzyme immobilization on different alkyl amino-agar beads, at different pH values (5.5 - 7.5), at different temperature (20 - 40 degrees C) and at different salt concentrations were investigated. The enzyme activity was measured at OD360 by reacting 133.3 ng/mL of AFB1 at 30 degrees C for 30 min with the immobilized ADTZ. The Km value of the immobilized enzyme, determined using Schematic Linewearver-Burk plot, is 3.308 x 10(-3) mol/L, lower than that of free enzyme, which is 2.16 x 10(-6) mol/L. This indicated the affinity of the detoxiczyme to AFB1 decreased after immobilization. The immobilized enzyme activity in oil-phase (n-hexane) was also studied with different concentration of water. After the treatment of the immobilized ADTZ, the toxin no longer causes liver toxicity in the rat toxicity test, no longer causes mutagenicity in Ames test and is no longer toxic in the chicken embryo test. Results also indicated that the pH stability, the thermostability and the freezing stability of ADTZ were improved after the immobilization.

Production, purification, and characterization of an intracellular aflatoxin-detoxifizyme from Armillariella tabescens (E-20)

Some Armillariella tabescens (E-20) multienzymes have previously been reported to present detoxifying activities against aflatoxins. In this paper, we describe the isolation purification of an intracellular enzyme, named aflatoxin-detoxifizyme, which exhibited detoxification activity on aflatoxin B(1) (AFB(1)). This aflatoxin-detoxifizyme exhibited a specific activity of 7.09 nmol min/mg at pH 6.0 and 28 degrees C. The apparent molecular mass was 51.8 kDa as determined by SDS-PAGE. The isoelectric point was estimated to be 5.4 and optimum activity for the enzyme was found at pH 6.8 and 35 degrees C. The activity of the purified enzyme was confirmed by Ames test.

Detoxification of aflatoxin B1 by enzymes isolated from Armillariella tabescens

Detoxification of aflatoxin B1 (AFB1) by Armillariella tabescens multienzyme, which was isolated from mycelium pellets of A. tabescens, was confirmed by thin-layer chromatography (TLC) and rat assay. The results of toxicology and pathology studies showed that toxicity of AFB1 was minimized after treatment with A. tabescens multienzyme. The result of the Ames test indicated that the mutagenic activity of multienzyme-treated AFB1 was greatly reduced (or inactivated) compared with that of untreated controls. TLC determinations showed that AFB1 at an initial concentration of 16 microM was completely detoxified (100%) by the fungal multienzyme. The infrared spectrum suggests that the multienzyme is responsible for opening the difuran ring of AFB1.

Differential expression of telomerase activity in human cervical cancer and cervical intraepithelial neoplasia lesions

PURPOSE

Telomeres are tandem arrays of repeated DNA sequences located at the ends of eukaryotic chromosomes, and are synthesized by the enzyme telomerase. Loss of telomeric DNA may play an important role in the development of human cancers. However, very little is known about the status of telomerase during human cervical cancer development.

PATIENTS AND METHODS

Telomerase activity was measured by telomere repeat amplification protocol (TRAP) assay in 24 cervical cancers, one carcinoma in situ (CIS), and 20 cervical intraepithelial neoplasia (CIN) lesions. Adjacent nontumor cervical tissue from the same 24 cervical cancer patients and normal cervical tissues from 11 control individuals also were examined for the presence of telomerase activity.

RESULTS

Twenty two of the 24 (91.7%) cervical cancer specimens and the single CIS tissue were strongly positive for telomerase activity. Relatively weak but distinctive telomerase activity also was detectable in one of four CIN-I (25%), two of eight CIN-II (25%), and two of eight CIN-III (25%), respectively. However, telomerase activity was not found in the 24 corresponding nontumor cervical tissues from the same cervical cancer patients and the 11 normal cervical tissues from control individuals.

CONCLUSION

The majority of cervical cancers contain strong telomerase activity. Significant proportions of noncancerous CIN tissues also contain telomerase activity, although weaker than that in cervical cancer. It seems that there is a progressive increase of telomerase activity in association with an increased degree of cervical malignancy. These results seem to suggest that the expression of telomerase may play a crucial role in cervical cancer carcinogenesis.

Genomic aberrations of human papillomavirus recovered from cervical cancers

Human papillomaviruses (HPV) contribute to the development of malignancies of the uterine cervix and the viral E6 and E7 oncogenes are invariably retained and expressed in cervical cancer tissues. Minor, but not major, structural aberrations have been found quite frequently in viral DNA recovered from cervical cancer tissues. We examined the presence of the DNA sequence of HPV type 18 in 33 cervical cancer tissues by polymerase chain reaction. HPV type 18 DNA sequences was found in 24 of these 33 cervical cancer tissue specimens, and at least 21 of these 24 specimens did not appear to retain all the region and open reading frames examined. Twelve of these 24 tissues seemed to harbor only the E6 and/or E7 genes. These results can be construed to suggest that the absence of viral genes other than E6 and E7 is quite frequent in HPV recovered from cervical cancer tissues and that the E6 and E7 genes are important in the carcinogenesis of cervical carcinoma. It is possible that the E6 and/or E7 alone may be sufficient to maintain the transformed phenotype of cervical cancer.

Differential expression of cytokine genes in cervical cancer tissues

The expression of genes coding for inflammatory cytokine interleukin-1-alpha (IL-1 alpha), IL-6, interferon-gamma and tumor necrosis factor-alpha from 15 normal cervix, 11 cervical intraepithelial neoplasia and 13 cervical cancer tissues was investigated. The cytokine messenger ribonucleic acids were reverse transcribed and amplified in the presence of biotinylated and dinitrophenylated primers. Amplified DNA was then captured onto streptavidin-coated microwell plate and quantitatively measured in a colorimetric reaction using ant-DNP antibodies conjugated to horse radish peroxidase. There is no change of IL-1 alpha, IL-6 and tumor necrosis factor-alpha gene expression in either cervical intraepithelial neoplasia or cervical cancer tissues. But the transcription of interferon-gamma gene is significantly reduced in both cervical intraepithelial neoplasia and cervical cancer tissue as compared to normal cervix. This study demonstrated that reverse transcription and quantitative polymerase chain reaction coupling to colorimetric microwell plate assay is a sensitive and useful method to quantitate multiple cytokine gene expression. Our results also suggest that cervical epithelial cells are capable to express cytokines and that interferon-gamma may play a role in the pathogenesis of cervical cancer since its reduced expression may influence inflammation and immunity of the cervical tissues.

Hepatitis C virus in peripheral blood mononuclear cells

RNA extracted from plasma and peripheral blood mononuclear cells of patients with chronic hepatitis C were used as the template for reverse transcription followed by double in vitro enzymatic amplification with nested primers. Hepatitis C virus was detected in 14 of 15 (93.3%) plasma specimens and in 8 of 15 (53.3%) peripheral blood mononuclear cell specimens obtained from patients with chronic hepatitis C and abnormal liver functions. The results suggest that hepatitis C virus could be found frequently in peripheral blood mononuclear cells of patients with chronic hepatitis C. Whether the presence of hepatitis C virus in peripheral blood mononuclear cells plays any role in the pathogenesis of diseases associated with hepatitis C virus infection remains to be determined.

Amplification of viral RNA for the detection of dengue types 1 and 2 virus

In vitro DNA amplification by means of the polymerase chain reaction (PCR) was used to amplify dengue types 1 and 2 viral genomes in cultured cells and in the serum of persons infected with dengue virus. Results of the present investigation suggest that the PCR method is type-specific in detecting dengue virus and has a detection sensitivity of less than 100 plaque-forming units (pfu) for both serotypes of the virus. The PCR method may be useful for detecting and typing dengue virus in clinical and epidemiological specimens.

Prenatal transmission of hepatitis B virus to neonates born to serum hepatitis B virus DNA-positive mothers

Hepatitis B virus (HBV) DNA was detected by in vitro enzymatic DNA amplification techniques in 66.7% (six of nine) of hepatitis B virus surface antigen (HBsAg)-positive and in 21.1% (7 of 33) of HBsAg-negative pregnant women. Five of the HBV DNA and HBsAg-positive women and one HBV DNA-positive but HBsAg-negative woman gave birth to infants positive for serum HBV DNA at time of birth. These results suggest that HBsAg-negative pregnant women are potentially capable of transmitting HBV DNA to their infants.

Hepatitis B virus DNA in cervicovaginal cells

Hepatitis B virus DNA sequences were detected in seven (12.1%) of 58 cervicovaginal cell specimens that were obtained from pregnant women by polymerase DNA amplification assay. The presence of hepatitis B virus DNA in these cells raises the possibility that infected cervicovaginal cells may be a source through which hepatitis B virus can be transmitted from infected mothers to their newborns and between heterosexual partners.

Serum hepatitis B virus DNA in hepatitis B virus seropositive and seronegative patients with normal liver function

The presence of hepatitis type B virus (HBV) DNA in serum specimens from 926 apparently healthy people with normal liver functions was determined by polymerase chain reaction; 41.2% of people with positive results for HBV surface antigen (HBsAg) (94 of 228) and 95.2% of people with positive results for HBV e antigen (HBeAg) (60 of 63) were found to have positive results for serum HBV DNA. On the other hand, serum HBV DNA was found in 11.0% (77 of 698) of HBsAg-negative people and in 13% (69 of 530) of those who had positive results for serum antibodies directed against HBsAg. The results seem to suggest that HBV DNA can be found in a significant portion of apparently healthy people with normal liver function who are either seronegative for HBsAg or seropositive for antibodies directed against HBsAg.