Comparison of the broody behavior characteristics of different breeds of geese.

A low laying performance in goose is one of the key factors preventing the industrial development, and the laying performance is related to broody behavior. However, the characteristics of broody behavior in geese remain unclear. In this study, the total 144 geese (300 day old), including Zhedong geese (Anser cygnoides), Sichuan geese (Anser cygnoides), and Carlos geese (Anser anser) were selected and assigned to 1 of 3 groups/breed (including 4♂+12♀). Laying and broody behaviors were recorded using the infrared video cameras from 2016 November 11 to 2017 June 15. The broody behavior was detected in 19.4% of Carlos geese, 33.3% of Sichuan geese, and 100% of Zhedong geese. Different goose breeds showed similar behavior characteristics. The low frequency of feeding, drinking, and low body weight were observed in the middle of broodiness. As the brooding progressed, the body temperature showed a downward trend and then recovered, whereas no difference was observed in Carlos goose. In addition, the plasma hormone concentration from different breeds and stages of broodiness were compared. The contents of FSH (follicle-stimulating hormone) and LH (luteinizing hormone) in geese were greater in the laying stage than that in the broody stage. Fewer FSH and LH were detected in Zhedong geese and Carlos geese, more in Sichuan geese. In broody goose, the PRL (prolactin) concentrations of the 3 goose breeds peaked in the middle of broodiness, and greater PRL was detected in Sichuan geese than those in Carlos geese and Zhedong geese. Finally, we compared egg production between the broody and non-broody geese in the observation period. The egg production of broody Carlos geese was 27, which was significantly higher than non-broody geese (14 eggs), while in Sichuan geese there was no significant difference between broody (24 eggs) and non-broody geese (26 eggs). Finally, the higher egg production was found with the more broody times in Zhedong geese. Taken together, although the different goose breeds showed similar broody behavior characteristics, the broody rate and hormone secretion were dissimilar, and the Zhedong geese exhibited strong broody feature.

Comparisons in geese of the courtship, mating behaviors and fertility of the Carlos and Sichuan breeds and the breed crosses.

The Chinese goose originated from the swan goose (Anser cygnoides) and the European goose originated from the greylag goose (Anser anser). The Chinese and European geese have the potential to crossbreed. Whether interspecific differences in mating behaviors affect successful hybridization is unknown. In this study, 10-month-old Carlos geese (n = 120; Anser anser) and Sichuan geese (Anser cygnoides) were selected, and 12 multi-male parent families (3♂+12♀) were established. The courtship and mating behaviors of pure and cross-bred combinations of the Carlos and Sichuan geese were recorded using video cameras. Initiative courtship by males was the main type of courtship. Fixed mating, mating interference, and uncooperative mating were common in the flocks. The frequencies of some courtship and mating behaviors were less in the cross-bred groups (Carlos ganders × Sichuan geese, Sichuan ganders × Carlos geese) compared with the Sichuan pure-bred groups (P < 0.05). The Carlos male geese had some unique mating behaviors (i.e., one-to-one mating, formation of distinct hierarchies, and competition interference). The fertility rate had a significant correlation with the frequency of successful mating (rp = 0.992, P < 0.05), rather than with the courtship behavior. These results indicate there were lesser frequencies of courtship and successful matings in the cross-breeding than purebreeding groups. Furthermore, the fertility rate depended largely on the successful mating behavior and was independent of the courtship behavior.

Genetic association of HLA-DRB1 multiple polymorphisms with dermatomyositis in Chinese population.

Genetic variation in HLA plays an important role in the pathogenesis of dermatomyositis (DM). The aim of this study was to investigate the association of HLA class II with DM in China. Two hundred and twenty-four DM patients and 300 healthy controls were randomly enrolled at China-Japan Friendship Hospital. High-resolution typing of HLA-DRB1 alleles was performed by sequencing based typing. The HLA-DQA1 and HLA-DQB1 alleles were determined by polymerase chain reaction sequence-specific primers. The frequencies of HLA-DRB1*09:01 (28.6% vs 11.3%, P < .0001, odds ratio, OR = 3.14, 95% confidence interval, CI = 2.47-3.99) and HLA-DRB1*12:01 (29.0% vs 11.0%, P < .0001, OR = 3.30, 95% CI = 2.59-4.20) in DM patients were significantly higher than that in healthy controls. No significant difference was found in HLA-DQA1 or DQB1 alleles between DM patients and healthy controls. Furthermore, DM patients with anti-melanoma differentiation-associated gene 5 antibody (anti-MDA5) had a significantly higher frequency of HLA-DRB1*12:01 compared to that for patients without anti-MDA5 (P < .0001, OR = 4.77, 95% CI: 2.29-9.93). Multivariate binary logistic regression analysis was performed to identify the risk factors for interstitial lung disease. The HLA-DRB1*09:01 allele was a poor prognostic factor (P = .01, OR = 9.21, 95% CI: 1.47-57.50) for DM patients with anti-MDA5 autoantibody. In summary, our findings indicate that HLA-DRB1*09:01 and HLA-DRB1*12:01 alleles may contribute to susceptibility of adult DM in Han Chinese population. In addition, the DRB1*12:01 genotype is significantly associated with the presence of anti-MDA5 antibody in DM patients.

[Effects of both folic acid, p16 protein expression and their interaction on progression of cervical cancerization].

Objective: To explore the effects of both folic acid, p16 protein expression and their interaction on progression of cervical cancerization. Methods: Participants were pathologically diagnosed new cases, including 80 women with normal cervical (NC), 55 patients with low-grade cervical intraepithelial neoplasia (CINⅠ), 55 patients with high-grade cervical intraepithelial neoplasia (CINⅡ/Ⅲ) and 64 patients with cervical squamous cell carcinoma (SCC). Serum folate levels were detected by microbiological assay method while p16 protein expression levels were measured by Western-blot. In vitro, cervical cancer cell lines C33A (HPV negative) and Caski (HPV16 positive) were treated with different concentrations of folate. Proliferation and apoptosis of cells and the levels of p16 protein expression were measured in groups with different folic acid concentrations. Results: Results showed that the levels of serum folate were (5.96±3.93) ng/ml, (5.08±3.43) ng/ml, (3.92±2.59) ng/ml and (3.18±2.71) ng/ml, and the levels of p16 protein were 0.80±0.32, 1.33±0.52, 1.91±0.77, and 2.09±0.72 in the group of NC, CINⅠ, CINⅡ/Ⅲ and SCC, respectively. However, the levels of serum folate decreased (trend χ2=32.71, P<0.001) and p16 protein expression increased (trend χ2=56.06, P<0.001) gradually along with the severity of cervix lesions. An additive interaction was seen between serum folate deficiency and high expression of p16 protein in the CINⅠ, CINⅡ/Ⅲ and SCC group. Results in vitro showed that, with the increase of folate concentration, the inhibition rate of cell proliferation (C33A: r=0.928, P=0.003; Caski: r=0.962, P=0.001) and the rate on cell apoptosis (C33A: r=0.984, P<0.001; Caski: r=0.986, P<0.001) all increased but the levels of p16 protein expression (C33A: r=-0.817, P=0.025; Caski: r=-0.871, P=0.011) reduced. The proliferation inhibition rate (C33A: r=-0.935, P=0.002; Caski: r=-0.963, P=0.001) and apoptosis rate of cells (C33A: r=-0.844, P=0.017; Caski: r=-0.898, P=0.006) were negatively correlated with the levels of p16 protein expression. Conclusions: Our findings indicated that both serum folate deficiency and high expression of p16 protein could increase the risk of cervical cancer and cervix precancerous lesion, and there was an additive interaction between them. Our findings suggested that folic acid supplementation could reverse the abnormal expression of p16 protein, and effectively promote apoptosis and inhibit proliferation in cervical carcinoma cells.

[Evaluation of the efficacy of laparoscopic surgery in treatment of advanced mid-low rectal cancer following a long-term neoadjuvant chemoradiotherapy].

Objective: To explore the efficacy of laparoscopic surgery in treatment of advanced mid-low rectal cancer following a long-term neoadjuvant chemoradiotherapy. Methods: Clinicopathologic and perioperative data were collected retrospectively from 74 patients with advanced mid-low rectal cancer, who received both neoadjuvant chemoradiotherapy and resections between January 2010 and January 2013 at Xinjiang tumor hospital. Routine follow-up was conducted. The safety and long-term survival of 36 patients who underwent laparoscopic resection were compared with those of 38 patients who received conventional resection. Results: The laparoscopic group had less amount of blood loss during surgery (50 ml vs 100 ml, P<0.05). The time needed for recovery of gastrointestinal function in the laparoscopic group was significantly shorter than that in the open surgery group (2.0 d vs 3.0 d, P<0.05). The rate of postoperative complication was 19.4% and 42.1% (P<0.05), respectively. In terms of the range of radical surgery and the numbers of dissected lymph nodes (8 and 10, P>0.05), no significant difference were found in the two groups. The operation duration and hospital stay in the laparoscopic group was longer than that in the open surgery group (240.0 min vs 231.5 min , P>0.05) (22.0 d vs 21.5 d , P>0.05), but no significant difference was found between the two groups. There were no significant difference in the incidence of 3 disease-free survival rate (53.0% vs 43.8%, P>0.05) and overall survival rate (70.0% vs 62.9%, P>0.05) between two groups. Conclusion: Laparoscopic surgery is a safe and feasible option for advanced mid-low rectal cancer patients who undergone the neoadjuvant chemoradiotherapy because of the similar rate of radical resection and satisfied long-term outcomes, which will have a better prospect in the future.

Association between IL-17A and IL-17F gene polymorphisms and risk of gastric cancer in a Chinese population.

We conducted a case-control study to investigate the role of interleukin-17A (IL-17A) rs2275913 G > A and IL-17F rs763780 T > C polymorphisms in the development of gastric cancer. A hospital-based case-control design was performed, and 153 patients and 207 control subjects were consecutively selected from the Third Affiliated Hospital between May 2013 and December 2014. Polymerase chain reaction-restriction fragment length polymorphism was used to genotype for IL-17A rs2275913 G > A and IL-17F rs763780 T > C. The genotypes of IL-17A rs2275913 G > A and IL-17F rs763780 T > C did not deviate from Hardy-Weinberg equilibrium (P values were 0.44 and 0.11, respectively). By unconditional logistic regression analysis, we observed that the GG genotype of rs2275913 was associated with an increased risk of gastric cancer compared to the AA genotype [odds ratio (OR) = 2.66; 95% confidence interval (CI) = 1.26-5.66]. The AG + GG genotype of rs2275913 increased the susceptibility to gastric cancer compared to the AA genotype, and the adjusted OR (95%CI) was 2.66 (1.26-5.66). Moreover, the GG genotype of rs2275913 was correlated with an elevated risk of gastric cancer when compared with the AA + AG genotype (OR = 2.15; 95%CI = 1.08-4.34). In conclusion, we found that the IL-17A rs2275913 G > A gene polymorphism was significantly associated with an increased risk of gastric cancer in co-dominant, dominant, and recessive models.

[SPINK3: A novel growth factor that promotes rat liver regeneration].

Serine peptidase inhibitor, Kazal type 3 (SPINK3) is a trypsin inhibitor, and also a growth factor that has an identical structure to epidermal growth factor (EGF), which could combine with epidermal growth factor receptor (EGFR) to promote cell proliferation. To shed light on the role and regulation mechanism of SPINK3 in rat liver regeneration (LR), Rat Genome 230 2.0 assay was used to detect the expression profiles of LR genes after partial hepatectomy (PH). The results showed that Spink3 was significantly up-regulated at 2-24 h and 72-168 h after PH. In the present study, RT-PCR and immunoblotting were used to validate the assay results. Ingenuity Pathway Analysis 9.0 (IPA) software was used to build the SPINK3 signaling regulating LR and analyze the possible mechanism. And then the expression of cell proliferation-associated gene Ccna2 was examined by RT-PCR in normal rat liver cell line BRL-3A in which Spink3 was overexpressed. The results showed that Ccna2 was significantly up-regulated in BRL-3A in which Spink3 was over-expressed. SPINK3 combining with EGFR accelerated cell proliferation during rat liver regeneration via P38, PKC, JAK-STAT and AKT pathways. Thus, SPINK3 was likely to promote hepatocytes proliferation in LR through P38, PKC, JAK-STAT and AKT.

Branches of the NF-κB signaling pathway regulate proliferation of oval cells in rat liver regeneration.

The NF-kB (nuclear factor kB) pathway is involved in the proliferation of many cell types. To explore the mechanism of the NF-kB signaling pathway underlying the oval cell proliferation during rat liver regeneration, the Rat Genome 230 2.0 Array was used to detect expression changes of NF-kB signaling pathway-related genes in oval cells. The results revealed that the expression levels of many genes in the NF-kB pathway were significantly changed. This included 48 known genes and 16 homologous genes, as well as 370 genes and 85 homologous genes related to cell proliferation. To further understand the biological significance of these changes, an expression profile function was used to analyze the potential biological processes. The results showed that the NF-kB pathway promoted oval cell proliferation mainly through three signaling branches; the tumor necrosis factor alpha branch (TNF-a pathway), the growth factor branch, and the chemokine branch. An integrated statistics method was used to define the key genes in the NF-kB pathway. Seven genes were identified to play vital roles in the NF-kB pathway. To confirm these results, the protein content, including two key genes (TNF and FGF11) and two non-key genes (CCL2 and TNFRSF12A), were analyzed using two-dimensional gel electrophoresis and MALDI-TOF/TOF mass spectrometry. The results were generally consistent with those of the array data. To conclude, three branches and seven key genes were involved in the NF-kB signaling pathway that regulates oval cell proliferation during rat liver regeneration.

Branches of NF-κb signaling pathway regulate hepatocyte proliferation in rat liver regeneration.

Previous studies have demonstrated that the nuclear factor κB (NF-κB) pathway is involved in promoting cell proliferation. To further explore the regulatory branches and their sequence in the NF-κB pathway in the promotion of hepatocyte proliferation at the transcriptional level during rat liver regeneration, Rat Genome 230 2.0 array was used to detect the expression changes of the isolated hepatocytes. We found that many genes involved in the NF-κB pathway (including 73 known genes and 19 homologous genes) and cell proliferation (including 484 genes and 104 homologous genes) were associated with liver regeneration. Expression profile function (Ep) was used to analyze the biological processes. It was revealed that the NF-κB pathway promoted hepatocyte proliferation through three branches. Several methods of integrated statistics were applied to extract and screen key genes in liver regeneration, and it indicated that eight genes may play a vital role in rat liver regeneration. To confirm the above predicted results, Ccnd1, Jun and Myc were analyzed using qRT-PCR, and the results were generally consistent with that of microarray data. It is concluded that 3 branches and 8 key genes involved in the NF-κB pathway regulate hepatocyte proliferation during rat liver regeneration.

Gene expression profiling analysis of 5-hydroxytryptamine signaling pathway in rat regenerating liver and different types of liver cells.

We examined the gene expression profiles of the 5-hydroxytryptamine signaling pathway in the regenerating liver and 8 types of liver cells during rat liver regeneration, and explored expression differences in 5-hydroxytryptamine signaling pathway genes at the level of tissues and cells, as well as the role of the pathway on liver regeneration. Eight types of rat regenerating liver cells were isolated using Percoll density-gradient centrifugation and immunomagnetic bead methods. Rat Genome 230 2.0 Array was used to detect expression changes in 5-hydroxytryptamine signaling pathway genes. The results showed that 26, 47, 8, 21, 16, 19, 22, 27, and 20 genes changed significantly in hepatocytes, biliary epithelial cells, hepatic stellate cells, oval cells, sinusoidal endothelial cells, Kupffer cells, pit cells, dendritic cells, and the regenerating liver, respectively. Synthetic effects of 5-hydroxytryptamine signaling pathway genes in 8 types of liver cells showed that 26 genes were expressed significantly; the expression trends of 10 genes were the same in the regenerating liver, while others were different. Based on the gene expression profiles of the 8 types of liver cells, 5-hydroxytryptamine promoted hepatocyte proliferation through the RAS and STAT3 signaling pathways, proliferation and differentiation of sinusoidal endothelial cells through the STAT3 signaling pathway, and proliferation and apoptosis of pit cells through the AKT3 signaling pathway. There were large differences in genes involved in 5-hydroxytryptamine signaling at the tissue and cellular levels; thus, liver regeneration should be studied in-depth at the cellular level to reveal the molecular mechanism of liver regeneration.

Quantitative trait loci mapping of leaf angle and leaf orientation value in maize (Zea mays L.).

A major limiting factor for high productivity of maize (Zea mays L.) in dense planting is light penetration through the canopy. Plant architecture with a narrower leaf angle (LA) and an optimum leaf orientation value (LOV) is desirable to increase light capture for photosynthesis and production per unit area. However, the genetic control of the plant architecture traits remains poorly understood in maize. In this study, QTL for LA, LOV, and related traits were mapped using a set of 229 F(2:3) families derived from the cross between compact and expanded inbred lines, evaluated in three environments. Twenty-five QTL were detected in total. Three of the QTL explained 37.4% and five of the QTL explained 53.9% of the phenotypic variance for LA and LOV, respectively. Two key genome regions controlling leaf angle and leaf orientation were identified. qLA1 and qLOV1 at nearest marker umc2226 on chromosome 1.02 accounted for 20.4 and 23.2% of the phenotypic variance, respectively; qLA5 and qLOV5 at nearest bnlg1287 on chromosome 5 accounted for 9.7 and 9.8% of the phenotypic variance, respectively. These QTL could provide useful information for marker-assisted selection in improving performance of plant architecture with regard to leaf angle and orientation.

Behavior differentiation between wild Japanese quail, domestic quail, and their first filial generation.

The number of wild quail has dramatically reduced in China and reached a state of endangerment with the deterioration of the environment in recent years. In this study, we examined the ecological behaviors of quails in the cage to determine the differentiation level between wild Japanese quail and domestic quail, to detect the relationship between quail behavior and evolutionary differentiation and to analyze the possibility of restoring effective size of wild population. With the on-the-spot observations and measurements, the behaviors of 3 categories of quail, namely wild Japanese quail from the Weishan Lake area in China, domestic quail, and their first filial generation (F(1)) were studied. Domestic quail differed from wild Japanese quail in morphological pattern and ecological behaviors, including some indexes of figure type and egg, vocalization, aggression and fighting, and mating, but wild Japanese quail and domestic quail could succeed in mating and reproducing fertile hybrid offspring. There were significant differences between domestic quail and wild Japanese quail in reproductive traits, involved mating times, fertility rate, hatching rate, and hatching rate of fertilized eggs (P < 0.05). The first filial generation presented significant difference from the wild Japanese quail in vocalization, aggression and fighting, mating, hatching rate, hatching rate of fertilized eggs, and some egg indexes (P < 0.05) and significantly differ from the domestic quail in vocalization, hatching rate, and hatching rate of fertilized eggs (P < 0.05). Evolutionary differentiation between wild quail and domestic quail was still at a relatively low level because no reproductive isolation existed. The advantages of the F(1) hybrids in reproductive capacity, fertilization, and hatching recommend that releasing hybrids instead of domestic quails to the wild would be a more effective way to restore the effective size of wild quail population if necessary.

Pharmacological studies of the large-scaled purified genistein from Huaijiao (Sophora japonica-Leguminosae) on anti-osteoporosis.

In this report, we used genistein that was extracted from a Chinese herbal medicine Huaijiao (Sophora japonica-Leguminosae) to evaluate its pharmacological function on anti-osteoporosis. This genistein is purified in a large-scale production from Huaijiao by a state-of-art method as described by Tian et al. [2004. The preparation of genistein and LC-MS/MS on-line analysis. Drug Devel. Res. 61, 6-12]. Chemical structure of the isolated genistein was examined by using various techniques including nuclear magnetic resonant spectrum, infrared absorption spectrum, ultraviolet absorption spectrum and mass spectrum, and was proved to be identical to those purified from soybean in a small scale as previously reported. We randomly divided female SD rats into 6 groups, including control, ovariectomized model, Nilestriol-treated, and three level of dosages of genistein-treated. We evaluated the pharmacological effects of genistein against osteoporosis by measuring the bone density of femur and bone mineral group including calcium, phosphorous, and magnesium. The consequences of genistein treatment on bone histology and morphology were also determined by measuring the trabcular area, thickness and number. Our results indicated that treatment with a 4.5 or 9 mg/kg dosage of genistein could also prevent osteoporosis significantly at the 4th week after treatment. In comparison with the anti-osteoporosis effects of soybean genistein, the genistein extracted from Huaijiao has the same beneficial effect on anti-osteoporosis.

Renal replacement lipomatosis.

We report a relatively rare case of renal replacement lipomatosis presenting as a renal mass. Computed tomography revealed a predominantly low-density and roundish mass, with an irregular renal parenchyma, high-density calcification, and abundant low-density fat. The differential diagnosis before surgery was squamous cell carcinoma, teratoma, or angiomyolipoma of the kidney. The case was initially misdiagnosed, because we had no experience with this disease. After mass exploration, histological examination confirmed the diagnosis of renal replacement lipomatosis. The patient was free from signs of recurrence 10 months after the operation.

Constituents from the leaves of Rhododendron latoucheae.

Twelve constituents from Rhododendron latoucheae were isolated. Among them, compounds 1 and 2, named rhodolatouside A and B, respectively, are new iridoids.

A proline-rich protein binds to the localization element of Xenopus Vg1 mRNA and to ligands involved in actin polymerization.

A 340 nucleotide element within the 3' untranslated region of Vg1 mRNA determines its localization to the vegetal cortex of Xenopus oocytes. To identify protein factors that bind to this region, we screened a cDNA expression library with an RNA probe containing this sequence. Five independent isolates encoded a protein (designated Prrp for proline-rich RNA binding protein) having two RNP domains followed by multiple polyproline segments. Prrp and Vg1 mRNAs are co-localized to the vegetal cortex of stage IV oocytes, substantiating an interaction between the two in vivo. Prrp also associates with VegT mRNA, which like Vg1 mRNA uses the late localization pathway, but not with Xcat-2 or Xwnt-11 mRNAs, which use the early pathway. The proline-rich domain of Prrp interacts with profilin, a protein that promotes actin polymerization. Prrp can also associate with the EVH1 domain of Mena, another microfilament-associated protein. Since the anchoring of Vg1 mRNA to the vegetal cortex is actin dependent, one function of Prrp may be to facilitate local actin polymerization, representing a novel function for an RNA binding protein.

Four mono-tetrahydrofuran ring acetogenins, montanacins B-E, from Annona montana.

Four novel mono-tetrahydrofuran (THF) acetogenins, montanacins B-E (1-4), were isolated from the ethanolic extract of the leaves of Annona montana. The structures of 1-4 were established by spectroscopic methods and their absolute stereochemistries were determined by the advanced Mosher ester method. Montancins D (3) and E (4) bear a non-adjacent tetrahydropyran (THP) ring along with a THF ring and are the most unusual type of acetogenins discovered so far.

Evaluation of toxicity of some saponins on brine shrimp.

Toxicity of several types of saponins (1-11) against brine shrimp (Artemia salina) were evaluated. As a result, it was found that most tested compounds were not toxic to brine shrimp at high enough concentration. The most toxic saponin (1) to brine shrimp showed also cytotoxicity towards HL-60 tumor cell line using MTT assay. Brine shrimp model may thus be used as bench-top assay in finding cytotoxic components from saponin-containing fractions of plant extracts.

Triterpenes and triterpenoid saponins from Mussaenda pubescens.

Two novel triterpenoid saponins, named mussaendosides U and V, together with one known saponin and four known triterpenes were isolated from the aerial parts of Mussaenda pubescens (Rubiaceae). The structures were determined on the basis of chemical analysis ad spectral methods. All these compounds were identified for the first time from the genus Mussaenda.

A research for the relationship between human papillomavirus and human uterine cervical carcinoma. II. Molecular genetic and ultrastructural study on the transforming activity of recombinant retrovirus containing human papillomavirus type 16 subgenomic sequences.

In order to elucidate the role of HPV-16 in the development of genital cancer, NIH3T3 cells were transfected by HPV-16 whole genome and its two early genes, E6-E7. Besides ordinary calcium phosphate/DNA coprecipitation technique, a newly designed recombinant retrovirus containing the HPV-16 genome or subgenomes was used to infect cells for transfer of the target genes. The transforming activities have been demonstrated to be most efficient when a bioengineering technique of this kind is used. HPV-16 DNA was proved to have transforming potential for NIH3T3 cells, and the DNA of HPV-16 was proved to undergo multisite integration into transformed cells and nude mice tumour cells. The E6-E7 open reading frames are sufficient for transforming NIH3T3 cells independently in vitro, which implies that E6-E7 open reading frames are transforming genes or even viral oncogenes of HPV-16. The RNA transcribed by the E6-E7 of HPV-16 was expressed in transformed cells and in tumour cells of nude mice. The use of a recombinant retrovirus for gene transfer in this study is much more efficient than that of calcium phosphate/DNA coprecipitation. The lack of a tissue-culture system suitable for HPV replication in vitro makes HPV gene recombination into a specially engineered retrovirus for viral-mediated gene transfer of particular significance for the possible application of viral carcinogenesis, both in vitro and in vivo, for basic and clinical research.