Immunogenicity of porcine transmissible gastroenteritis virus spike protein expressed in plants

Transgenic plants expressing recombinant proteins from pathogenic microorganisms provide an inexpensive edible vaccine for induction of local immunity. Three transgenic plant lines were generated expressing the spike (S) protein of transmissible gastroenteritis virus (TGEV), a protein crucial for establishing mucosal immunity. All three of them were driven by a strong plant promoter. One construct contained the 3.7 kb 5' end of the native S gene sequence. In the second construct part of the S gene, from nucleotide 49 to 1785, was modified for optimal plant recognition and was fused to a plant signal peptide coding sequence. The third construct contained the D epitope-coding region of the S gene, from nucleotide 1201 to 1591, which was fused to the alfalfa beta-amylase gene. The S gene products were detected by enzyme-linked immunosorbent assay (ELISA) and Western blotting. Antigens from all three transgenic plant lines induced TGEV-specific immune responses in pigs as determined by virus neutralization and ELISA, and the resultant antibody titers for all three constructs were similar.

[Measurement of human retinal thickness at posterior pole with retinal thickness analyzer in normal and glaucomatous eyes]

OBJECTIVE

To determine the diagnostic value of retinal thickness analyzer (RTA) in glaucoma.

METHODS

RTA was used to measure the retinal thickness at the posterior pole in 77 normal persons (116 eyes) at various ages and 22 cases (35 eyes) with glaucoma. The obtained images were processed by a computer to yield the retinal thickness value and the thickness map at this location, and the data were analyzed with SAS software package.

RESULTS

The mean retina thickness of normal subjects was (171.83 +/- 18.50) microm with no significant difference among the various age groups (F = 2.68, P > 0.05), and very significant between the sexes; the thickest retina was at the location between macula and optic nerve head, and the macular nasal retina is 11.7% thicker than its temporal side. The upper and lower retinas of the fovea were basically symmetrical. The retinal thickness in glaucoma patients showed diffuse or local thinning, and there was a very significant difference between the normal group and the glaucomatous group in retina thickness (F = 11.98, P = 0.0001). The sensitivity rate for detecting glaucoma with RTA was up to 80.8%, and specificity to 78.5%.

CONCLUSIONS

The thickness map for the retina at posterior pole across the macula in normal subjects is "horse shoe" shaped, that is well matched with the topography of retinal ganglion cell and the retinal nerve fibers in human retina. Diffuse or local thinning of retinal thickness in glaucomatous patients, which is in agreement with the corresponding visual field defect, and the sensitivity of RTA is higher than that of perimeter. The RTA examination is easy to operate, has high reproducibility, no invasion, therefore it is an ideal method to measure the human retinal thickness in vivo.

Establishment of labeling primer reverse transcription in situ polymerase chain reaction and detection of hepatitis C virus in liver tissues

OBJECTIVE

To establish bio-11-photosoralen (BP) labeling primer reverse transcription in situ polymerase chain reaction (PCR), and to detect the location and distribution of hepatitis C virus in 30 cases liver tissues embedded with paraffin.

METHODS

BPs were labeled in tymidine (T) position under ultraviolet lamp. The method was compared with indirect RT-in situ PCR and in situ hybridization for detecting hepatitis C virus (HCV) RNA.

RESULTS

Serum HCV PCR and southern blot showed that BP labeling psimer PCR was possible, and had a good specificity. The HCV positive rate was 53% (16/30) by indirect in situ PCR, 50% (15/30) positive specimens were found by BP labeling primer in situ PCR. Statistical analysis revealed P > or = 0.05 and the two methods had no dominant differences. Meanwhile, only 23% (7/30) positive signals were seen by in situ hybridization, which was lower than two in situ PCR(P < or = 0.05). HCV was mainly located in hepatic-plasmas, and positive signals were found in monocytes and cholangiolar epithelia.

CONCLUSIONS

Both indirect in situ PCR and BP labeling in situ PCR have good sensitivity and specificity for detecting HCV RNA of liver tissues. HCV RNA is located in hepatocytes, monocytes and cholangiolar epithelia.

Current methods for estimating dietary iron bioavailability do not work in China

Three current equations for estimating iron bioavailability were evaluated, and adjustments were proposed that would allow us to most effectively study iron bioavailability in China. Dietary intake data were obtained from 24-h dietary recalls taken over three consecutive days as part of the third Chinese National Nutrition Survey. Hemoglobin status was measured for 42,606 Chinese adults aged 18-60 y. The mean iron intake was 24.4 mg per capita per day, which was 177% of the Chinese RDA (209% of U.S. RDA). About 18% of the sample was classified as being anemic, indicating a large iron deficiency anemia and iron bioavailability problem in China. A number of methods proposed by World Health Organization and U.S. scholars were examined for adjusting iron bioavailability. Even the methods that consider several iron enhancers and inhibitors did not work adequately for the Chinese diet. The statistical assessment of the fit between iron bioavailability and hemoglobin status provided direction for adjusting the best of these predictive equations. We propose a new predictive approach for iron bioavailability which is more predictive of Chinese iron status. Consideration of additional dietary elements such as rice and bean consumption patterns are important. Our findings provide insight into additional factors which may influence iron bioavailability as well as possible improved methods for estimating the combined effect of multiple dietary factors on iron bioavailability, particularly in a vegetarian diet.

Preliminary studies on the application of retinal thickness analyzer in the diagnosis of glaucoma

The patients with glaucoma underwent the examination of retinal thickness analyzer (RTA) to explore the diagnostic value of RTA in glaucoma. The retina of 6 mm x 6 mm size (approximately 20 degrees, centered on the macula) at the posterior pole was scanned by using RTA to obtain the images in 35 eyes of 22 patients with glaucoma. The images were processed by using SAS software package. The retinal thickness in the patients with glaucoma showed diffuse or local thinning. Twenty-seven eyes was definitely diagnosed as having glaucoma. There was a very significant difference in retinal thickness measurements by RTA between normal group and glaucomatous group (P = 0.0012). Except the measurements at the detected point 6 having no difference, the measurements at the detected point 3 showed a significant difference and the remaining 7 detected points presented a very significant difference between the two groups. Of the detected 9 points, the changes at the points 4, 8, and 9 were the most obvious. The discrete analysis was performed on the glaucomatous patients by a discriminant function established through the data at the detected points 4, 8 and 9 and the accurate estimate rate for the diagnosis of glaucoma was up to 80.77%. The measurements of RTA examination was consistent with the results of the vision field test. It was suggested that diffuse or local thinning of retinal thickness exists in the patients with glaucoma. The temporal inferior arcuate fibers and the papillomacular bundle between the macular and optic nerve heads showed a serious damage. The sensitivity of RTA examination was higher than visual field test.

Towards the development of novel antibiotics: synthesis and evaluation of a mechanism-based inhibitor of Kdo8P synthase

The design and two synthetic pathways to aminophosphonate 4 which mimics the ionic and steric properties of putative oxocarbenium intermediate 3 in the Kdo8P synthase-catalyzed reaction are reported. It was found that 4 is a slow-binding, most potent inhibitor of the enzyme yet tested, with a Ki value of 0.4 microM.

Regulated expression of a highly conserved regulatory gene cluster is necessary for controlling photosynthesis gene expression in response to anaerobiosis in Rhodobacter capsulatus

We utilized primer extension analysis to demonstrate that the divergently transcribed regB and senC-regA-hvrA transcripts contain stable 5' ends 43 nucleotides apart within the regB-senC intergenic region. DNA sequence analysis indicates that this region contains two divergent promoters with overlapping sigma70 type -35 and -10 promoter recognition sequences. In vivo analysis of expression patterns of regB::lacZ and senC-regA-hvrA::lacZ reporter gene fusions demonstrates that the regB and senC-regA-hvrA transcripts are both negatively regulated by the phosphorylated form of the global response regulator RegA. DNase I protection assays with a constitutively active variant of RegA indicate that RegA binds between regB and senC overlapping -10 and -35 promoter recognition sequences. Two mutations were also isolated in a regB-deficient background that increased expression of the senC-regA-hvrA operon 10- and 5-fold, respectively. As a consequence of increased RegA expression, these mutants exhibited elevated aerobic and anaerobic photosynthesis (puf) gene expression, even in the absence of the sensor kinase RegB. These results indicate that autoregulation by RegA is a factor contributing to the maintenance of an optimal low level of RegA expression that allows responsiveness to activation by phosphorylation.

In vitro activation and repression of photosynthesis gene transcription in Rhodobacter capsulatus

It has been known for over half a century that anoxygenic photosynthetic bacteria maximally synthesize their photosystems in the absence of oxygen. During the last decade, it has become clear that this regulation is largely at the transcriptional level, with photosynthesis genes expressed only under anaerobic conditions. We describe here in vitro reconstitution of activation and repression of three photosynthesis promoters, bch (bacteriochlorophyll biosynthesis), puc (light-harvesting II apoproteins) and puf (reaction centre and light-harvesting I apoproteins) using purified transcription factors and RNA polymerase from Rhodobacter capsulatus. Previous genetic results have indicated that each of these three promoters is differentially regulated by three key regulators: CrtJ acting as a repressor of bch and puc and the two-component regulators RegA/RegB, which are activators of puc and puf. These regulators are distinct from those that mediate oxygen control in enteric bacteria. Our in vitro studies show that these purified regulators directly control the expression of the housekeeping RNA polymerase at these promoters. High-level basal expression of the bch promoter is shown to be repressed by CrtJ. The puc promoter is activated by the RegB-phosphorylated RegA protein and additionally repressed by CrtJ. At the puc promoter, CrtJ effectively competes for promoter binding with RegA, while at the bch promoter, repression appears to be by competition for the RNA polymerase binding site. In contrast to what has been suggested previously, the RegA-activated puf promoter is demonstrated as being recognized by the housekeeping RNA polymerase. We also discuss evidence that RegA approximately P activation of the puc and puf promoters involves recruitment of RNA polymerase by different modes of protein-protein interaction.

Autophosphorylation, phosphotransfer, and DNA-binding properties of the RegB/RegA two-component regulatory system in Rhodobacter capsulatus

In the purple, photosynthetic bacterium, Rhodobacter capsulatus, the RegB/RegA two-component system is required for activation of several anaerobic processes, such as synthesis of the photosynthetic apparatus and assimilation of CO2 and N2. It is believed that RegB is an integral membrane histidine kinase that monitors the external environment. Under anaerobic growth conditions, it transduces a signal through phosphorylation of the response regulator, RegA, which then induces target gene expression. We used an in vitro assay to characterize the phosphorylation of wild-type RegA and a mutant variant (RegA*) that is responsible for abnormally high photosynthesis gene expression under both aerobic and anaerobic growth conditions. Phosphorylation assays indicate that phosphorylated RegA* (RegA* approximately P) is much more stable than RegA approximately P, indicating that it may be locked in a conformation that is resistant to dephosphorylation. DNase I footprint assays also indicate that unphosphorylated RegA* has a much higher affinity for specific DNA binding sites than the wild-type protein. Phosphorylation of RegA* increases DNA binding 2. 5-fold, whereas phosphorylation of RegA increases DNA binding more than 16-fold. Collectively, these results support the hypothesis that RegA* is a constitutively active variant that does not require phosphorylation to assume a structural conformation required to bind DNA.

Calcium influx and activation of calpain I mediate acute reactive gliosis in injured spinal cord

Buffering extracellular pH at the site of a spinal cord crush-injury may stimulate axonal regeneration in rats (1; Guth et al., Exp. Neurol. 88: 44-55, 1985). We demonstrated in cultured astrocytes that acidic pH initiates a rapid increase in immunoreactivity for GFAP (GFAP-IR), a hallmark of reactive gliosis (2; Oh et al., Glia 13: 319-322, 1995). We extended these studies by investigating the effects of certain treatments on reactive gliosis developing in situ in a rat spinal cord injury model. A significant reactive gliosis was observed within 2 days of cord lesion in untreated crush or vehicle-treated, crush control animals as evidenced by increased GFAP-IR and hypertrophy of astrocytes. By contrast, infusion of Pipes buffer (pH 7.4) into the lesion site significantly reduced this increase. The increased GFAP-IR appeared to be linked to Ca2+ influx since infusion of a blocker of L-type calcium channels, nifedipine, reduced the ensuing reactive gliosis significantly. While Ca2+ modulates many signaling pathways within cells, its effect on reactive gliosis appeared to result from an activation of calpain I. Calpain inhibitor I, a selective inhibitor of mu-calpain, also significantly reduced reactive gliosis. However, calpain inhibitor II, a close structural analog which blocks m-calpain, had no salutary effect. We suggest, therefore, that the initial reactive gliosis seen in vivo may result from the activation of a neutral, Ca2+-dependent protease, calpain I, through calcium influx.

A clinical trial on yu cong tang in treatment of senile dementia

Yu Cong Tang ([symbol: see text]), a TCM decoction, was used to treat senile dementia. It has the action of invigorating the spleen, reinforcing the kidney, nourishing yin, strengthening yang, improving blood circulation, dredging the channels, removing phlegm and restoring consciousness. CT, EEG, REG, Hb, PaO2, Tch, TG and 17-OHCS were tested, showing significant differences (P < 0.05 or < 0.01) before and after the treatment. Remarkable improvement was found in clinical symptoms, and the effective rate was 94.1%. Significant differences were found between the TCM and western medicine (WM) groups in symptom improvement (P < 0.05-0.01) and therapeutic results (P < 0.001).

[Long-term follow-up of combined therapy with large-dose zinc sulfate and low-dose penicillamine in children with hepatolenticular degeneration]

OBJECTIVE

To summarize the long-term effect of combined treatment with large-dose zinc sulfate and low-dose penicillamine in children with hepatolenticular degeneration (HLD).

METHODS

The patients who had symptoms were treated with large-dose zinc sulfate (100-150mg, <6yr; 150-200mg, 6-8yr; 200-300mg, 9-10yr; 300mg,>10yr; 3 times a day) in addition to low-dose penicillamine(8-10mg/kg/d) at the beginning of treatment. Zinc sulfate alone was given to the presymptomatic patients and it was used as maintenance therapy when clinical improvement was obtained. 31 children were followed up for 4-11 years.

RESULTS

In 3 presymptomatic patients, no clinical abnormalities were found. Among 28 patients with symptoms, 23 patients (82%) had their symptoms and signs subsided or much improved, 2 patients(7%) remained unchanged, and 3(11%) died. Blood concentrations of copper were persistently lower than normal. Urine copper excretion of 24 hours was significantly lower than that before the combined therapy in all patients, and it became normal in 5 cases(16%) after 6 months of treatment, and in 26 cases(84%) after 1-2 years of treatment. Higher blood concentrations of zinc were found in 20 cases(65%), and higher urine zinc excretion was noted in 25 cases(81%) once or more times during the therapy.

CONCLUSION

Combined therapy of large-dose zinc sulfate and low-dose penicillamine is an effective, safe and cheap treatment for children with HLD.

[A study of interferon alpha-2b as an accessory drug after glaucoma filtration surgery]

OBJECTIVE

To elucidate the inhibitory action of interferon alpha-2b (IFN alpha-2b) on the cicatrization under conjunctiva and the best way to use it after glaucoma filtration surgery.

METHODS

Immunohistochemical PAP method and image biological system 2000 (IBAS 2000) were utilized to quantitatively analyze the inhibitory effect of IFN alpha-2b on the expression of epidermal growth factor receptor (EGFR) of cultured calf fibroblasts; the effects of IFN alpha-2b on collagen contents in suture-caused cicatrization under conjunctiva and changes of aqueous humor protein after trabeculectomy performed on rabbits have also been observed.

RESULTS

IFN alpha-2b reduced the expression of EGFR of cultured bovine fibroblasts at a dose-dependent manner. The relationship between the EGFR and the dosage of IFN alpha-2b is Y = 2953.8 - 554.5 lgx (r = -0.98, P < 0.01). With 4.67 x 10(-5) micromol/L IFN alpha-2b not only reduced about 50% of the collagen in suture-caused cicatrization, but also significantly decreased the protein concentration of aqueous humour 3 and 72 hours after trabeculectomy.

CONCLUSION

It is promising that IFN alpha-2b can be used after glaucoma filtration surgery to reduce excessive cicatrization with many advantages compared with antimetabolites.

Detection of GB virus C/hepatitis G virus RNA by reverse-transcription polymerase chain reaction

Recently, a novel RNA virus, designated GB virus C or hepatitis G virus (GBV-C/HGV) has been identified which may possibly be associated with human hepatitis. In this study, the nucleotide sequences of the partial nonstructural 5 (NS5) gene of GBV-C/HGV derived from sera of eight Chinese patients were determined. The overall degree of nucleotide conservation and the existence of regional highly conserved sequences make this part of the genome suitable for the development of diagnostic reagents. On the basis of sequence analysis, two sets of oligonucleotide primers were designed to establish a nested polymerase chain reaction (PCR) for detection of GBV-C/HGV RNA. The efficacy of three PCR methods (first, one stage PCR, second, nested PCR with primers from the NS5 region designed according to the prototype sequence and the third, our newly developed PCR) was compared in 133 Chinese patients with liver disease. The positive rates of these three methods were 8.3%, 11.3% and 18.0% respectively. The specificity of our PCR detecting system was verified by sequencing and restriction fragment length polymorphism (RFLP). In conclusion, because of the heterogeneity and geographic distribution character of GBV-C/HGV, it is necessary to assess the sequence variation among Chinese patients infected with GBV-C/HGV. This may allow to identify GBV-C/HGV RNA with high sensitivity and specificity.

Measurement of retinal thickness in normal subjects with retinal thickness analyzer

The retinal thickness at posterior pole of normal subjects was measured by using retinal thickness analyzer (RTA) to determine the values of retinal thickness and to establish map of retinal thickness in normal subjects. The retina of 6 mm x 6 mm in size (approximately 20 degrees, centered on the macula) at the posterior pole was scanned by using RTA to obtain images of 116 normal eyes of 77 cases of various age group. The images were processed by a computer to obtain the retinal thickness values and the thickness map of this location. The data were analyzed with SAS software package. The mean retinal thickness was 171.77 +/- 26.13 microns with no significant difference among the various age groups (P > 0.05). The thickness maps of the retina of 6 mm x 6 mm size at the posterior pole around the macula rendered a "U"-shaped pattern, extending from the disc to the superior and inferior of the fovea. The retina was found to be thin at temporal side of the fovea, with the thinnest area being at the macula central fovea. The U-shaped pattern of the retinal thickness maps was well in agreement with the topography of the ganglion cells and the retinal nerve fibers in human retina. The measurement of the retinal thickness by RTA reflected the changes in the layers of ganglion cells and the retinal nerve fiber. Each scanning session of RTA examination can yield multiple optical cross-section images of the retina and obtain retinal thickness maps of posterior pole of living eyes.

DNA binding characteristics of RegA. A constitutively active anaerobic activator of photosynthesis gene expression in Rhodobacter capsulatus

In the purple non-sulfur bacterium Rhodobacter capsulatus, RegA and RegB comprise a two-component regulatory system that is required for maximal anaerobic transcription of key photosynthesis genes. RegB is a sensor kinase that uses ATP to phosphorylate its cognate response regulator, RegA. The mechanism under which RegA approximately P influences transcription of target genes has been unclear given that past attempts to demonstrate DNA binding activity by isolated RegA have failed. This led to a model invoking a role for RegA approximately P as an intermediate in a more complex multicomponent phosphoryl transfer cascade. In the present study, we describe the isolation of a mutant version of RegA (RegA*) which promotes high level expression of photosynthesis genes independent of RegB. DNase I footprint analyses show that purified RegA* binds to the promoters of the puf and puc operons at locations that are consistent with RegA functioning as a transcriptional activator for these operons. We conclude that RegA functions, like most members of the response regulator family, as a DNA-binding protein that directly affects the expression of its target genes.

[An experimental study on mechanism of intraocular pressure decline after allogeneic transplantation of trabecular meshwork]

OBJECTIVE

To study the mechanism of intraocular pressure (IOP) decline after allogeneic transplantation of trabecular meshwork (TM) in primate experimental glaucoma.

METHODS

The experimental open-angle glaucoma models were created in 8 rhesus monkey eyes by repeated pangoniophotocoagulation on functional TM using argon laser. After 2, 3, 5 months respectively, avidin-gold or self-erythrocytes, which acted as tracers of the aqueous humor outflow, were perfused into the anterior chamber under normal pressure and volume conditions. 30 minutes later, 2.5% glutaraldehyde was perfused into the anterior chamber under the same conditions. Allograft TMs and photocoagulated area (serving as the control) were observed by light, transmission, scanning electron microscopy and ultrahistochemistry study.

RESULTS

The IOP of 5 eyes of 6 experimental eyes became normal. A blood reflux into Schlemm's canal was seen by gonioscopy in 4 eyes. The surface of TMs from graft showed the normal uveal TM cords and intertrabecular spaces. Erythrocytes were found in the intertrabecular spaces and Schlemm's canal. Avidin-gold and vacuolar containing gold were observed in the cells of TM and Schlemm's canal. The TMs of photocoagulated area appeared to be fewer and narrower intertrabecular spaces. The uveal cords of this zone were confused. The content of acid mucopolysaccharides in the grafts was closer to normal than that in the photocoagulated areas.

CONCLUSION

TM of allogeneic transplantation not only can survive but also function as an aqueous humor outflow pathway. We consider that this operative procedure can be used for treatment of some cases with glaucoma cautiously.

Genetic variability and characterization of non-structural region 5 of hepatitis C virus genome from Chinese patients

Sequence variation in the putative non-structural region 5b (NS5b) of hepatitis C virus (HCV) was analyzed in China. Complementary DNA fragments from sera of 49 Chinese patients were amplified by polymerase chain reaction (PCR) and the products were cloned and sequenced. Based on the comparison in NS5b of 33 clones of genotype 1b and 16 clones of genotype 2a, Chinese isolates of HCV belong to the same subtype as HCV-J, and HC-J6 from Japan. There does exist, however, some heterogeneity in the primary structure of the nucleotide acid. Higher homology was found among Chinese isolates than among Chinese isolates and Japanese isolates. Furthermore, among Chinese isolates, we found some conserved nucleotide acid positions different from those of Japanese isolates. Comparison of average homology among the 33 clones of genotype 1b and the 16 clones of genotype 2a indicated that the average homology among genotype 2a was lower than that among genotype 1b. In addition, a deletion of three nucleotide acids and a frame-shift, resulting in the introduction of an in-frame stop codon, were first observed in the NS5b region. These results indicated geographical differences in the distribution of individual HCV isolates, and the existence of a local variant in the same subtype. Our findings also suggested the need for further study on the sequence of genotype 2a, to improve diagnosis and help to advance the development of a vaccine.

[Studies on multiple infection with hepatitis B, C and G viruses]

OBJECTIVE

To study if there exists superinfection and multiple infection in the patients with hepatitis G virus (HCV) infection.

METHODS

Reverse transcription polymerase chain reaction (RT-PCR) technique in non-structural gene 3 (NS3) region of HGV was used to detect HGV RNA in serially diluted quality control sera and HGV-C reference panel of samples provided by Abbott Co. Ltd, in 90 cases with positive hepatitis C virus (HCV) RNA, and 12 blood donors with super-infection of hepatitis B virus (HBV) and hepatitis C virus (HCV).

RESULTS

Serially diluted quality control sera showed positive for HGV RNA at dilutions of 10(-1) to 10(-5), but negative at dilutions of 10(-6) to 10(-8). HGV RNA was positive in two samples of HGV-C serum provided by Abbott Co. HGV RNA was positive in eight of the 90 cases with positive HCV RNA and in four of the 12 cases with super-infection with HCV and HBV.

CONCLUSION

There are not only super-infection of HBV and HCV, but also multiple infection.

[Variation in hepatitis C virus NS 5b nucleotide sequence and its relationship with interferon treatment]

In order to investigate variation in hepatitis C virus (HCV) nonstructural 5b (NS5b) nucleotide sequence and the relationship with interferon treatment, cDNA containing in this region were obtained by reverse transcription-polymerase chain reaction from the sera of 4 HCV RNA positive asymptomatic chronic carriers and 9 chronic hepatitis C patients. The cDNA were then directly analysed by polymerase-chain-reaction-directed sequencing. Compared with three published HCV type II/1b sequences (HCV-J, HC-C2 and HCV-BDS), the homology of HCV was lower in the patients with chronic hepatitis C (93.52% +/- 2.09% average), especially in nonresponders to interferon (92.70 +/- 1.90% average), than in asymptomatic HCV carriers (95.65 +/- 2.61%). In 5 patients, HCV RNA was eliminated by interferon treatment. In the remaining 4 interferon-treated HCV survived patients there were 9-48 nucleotide substitutions in HCV mutants out of 380 nucleotides, resulting 6-20 amino acids changes out of 126 amino acids. These results suggested that NS5b region variants play an important role in maintaining persistent infection and the evolution of NS5b is associated with the effect of interferon treatment.

[Sequence analysis of 5' non-coding region of hepatitis G viruses and preliminary classification of genotypes]

For analyzing the structural characteristics of hepatitis G virus (HGV or GBV-C), 277 nucleic acids of 5' non-coding region of HGV were amplified using PCR from the sera of 2 paid donors, 2 chronic hepatitis patients and 2 patients with liver cirrohsis. The products were cloned and sequenced. The data were analyzed with the computer programs. The results indicated that the gene sequence homologies among 6 HGV isolates (G001-G006) obtained in this study were above 96.2%. The comparison of these 6 isolates and 3 foreign isolates reported previously showed that the sequence homologies were in the range from 86.9% to 91.6%. According to the variability of gene sequences, the preliminary division of genotypes of 6 Chinese HGV isolates (G001-G006) and 3 isolates reported abroad were classified into three distinct groups. The results suggest that the gene sequences of Chinese HGV isolates are highly homologous but have an obvious divergence with the foreign isolates. The 5' untranslated regions of all isolates analyzed probably contain a stable and similar secondary structure.

[Epidemiological study on human prostate cancer in Wuhan City]

In America, Canada and many European countries, prostate cancer is the most common cancer and the second leading cause of cancer death in men. In China, the morbidity rate and mortality rate of prostate cancer are unknown. Based on the reports of Wuhan cancer surveillance in 1990-1992, this study researched the epidemiological characterics of prostate cancer. The results showed that morbidity rate and mortality rate in Wuhan city are 1.37 and 0.75 per 100,000 respectively, and the standardized morbidity rate and standardized mortality rate are 1.10 and 0.66 per 100,000 respectively. They also showed that history of urinary diseases (OR = 5.42, 95% confidence interval (CI): 1.56-18.83), children number with more than 3 (OR = 2.43, 95% CI: 1.17-5.02), coitus with more than 3 times per week in youth (OR = 3.38, 95% CI: 1.51-7.58), frequent use of sexual drugs (OR = 4.12, 95% CI: 1.65-10.25) and high body mass index (OR = 2.58; 95% CI: 1.30-5.11) are identified as risk factors of prostate cancer statistically, but physical labor (OR = 0.35, 95% CI: 0.17-0.71) and age of first nocturnal emission after 18 years old (OR = 0.20, 95% CI: 0.08-0.52) are protective factors.

[Relationship between dietary nutrients intakes and human prostate cancer]

In order to study the relationship between dietary nutrients intakes and prostate cancer, 1 : 1 matched case-control study was carried out with 102 patients suffered from histologically confirmed prostate cancer and 102 healthy controls. Total calories and 11 nutrients including protein, lipid and carbohydrates were calculated based on the mean food intakes in the latest 3 days. Analyzed by matched t-test and conditional logistic regression method, the results showed that high intakes of lipid, carbohydrates, and retinol increased the risk of prostate cancer, but vitamin C and vitamin B1 decreased the risk of prostate cancer. The multivariable adjusted ORs were 1.65 (95% confident interval (CI) 1.39-1.96) for lipid, 1.22 (95% CI 1.13-1.31) for carbohydrates, 3.21 (95% CI 2.18-4.75) for retinol, 0.61 (95% CI 0.6-0.80) for vitamin C, and 0.029 (95% CI 0.009-0.09) for vitamin B1. The authors discussed the possible mechanism of dietary nutrients contributing to the risk of prostate cancer.

Cloning and characterization of PO22, a pollen-expressed gene in alfalfa

Genomic and cDNA clones have been isolated for a new gene (PO22) expressed in mature pollen of alfalfa. PO22 represents a single- or low-copy gene containing 4 introns, 2 transcriptional start sites, and coding for a predicted protein of 340 amino acids with no signal peptide and a coiled coil structure of 39 amino acids near the carboxyl end. The amino acid sequence of PO22 is 38% identical to that of an early nodule-specific gene (ENOD8), also from alfalfa.

PO149, a new member of pollen pectate lyase-like gene family from alfalfa

PO149 is a low-copy-number gene expressed in the late stages of pollen development. The promoter region contains no similarities in DNA sequence to those of other pollen-specific genes, except for a tobacco sequence (AAATGA), which occurs four times in this alfalfa gene and much further upstream than in tobacco. Four distinct TATA boxes were detected in the promoter with the distal and proximal TATA boxes being separated by a spacer of 269 nucleotides. Hairpin loop structures were found in the 5'- and 3'-untranslated regions of PO149 mRNA. The coding region of PO149 is interrupted by two introns and encodes a putative prepeptide of 450 amino acids with homology to pollen pectate lyase-like proteins and pollen allergens. The coding region also contains sequences characteristic of both a signal peptide and a nuclear localization signal.

Vaccinia virus DNA replication: two hundred base pairs of telomeric sequence confer optimal replication efficiency on minichromosome templates

Vaccinia virus is a complex DNA virus that exhibits significant genetic and physical autonomy from the host cell. Most if not all of the functions involved in replication and transcription of the 192-kb genome are virally encoded. Although significant progress has been made in identifying trans-acting factors involved in DNA synthesis, the mechanism of genome replication has remained poorly understood. The genome is a linear duplex with covalently closed hairpin termini, and it has been presumed that sequences and/or structures within these termini are important for the initiation of genome replication. In this report we describe the construction of minichromosomes containing a central plasmid insert flanked by hairpin termini derived from the viral genome and their use as replication templates. When replication of these minichromosomes was compared with a control substrate containing synthetic hairpin termini, specificity for viral telomeres was apparent. Inclusion of > or = 200 bp from the viral telomere was sufficient to confer optimal replication efficiency, whereas 65-bp telomeres were not effective. Chimeric 200-bp telomeres containing the 65-bp terminal element and 135 bp of ectopic sequence also failed to confer efficient replication, providing additional evidence that telomere function is sequence-specific. Replication of these exogenous templates was dependent upon the viral replication machinery, was temporally coincident with viral replication, and generated covalently closed minichromosome products. These data provide compelling evidence for specificity in template recognition and utilization in vaccinia virus-infected cells.

[Nested polymerase chain reaction (PCR) and multiple cloned antibody capture PCR for the examination of serum hepatitis B virus DNA in negative hepatitis B surface antigen patients suffering from liver diseases]

In order to find out rapidly the causes of the liver diseases suffered by patients with negative hepatitis B surface antigen (HBsAg), nested polymerase chain reaction (PCR) and multiple cloned antibody capture PCR techniques were established to examine serum hepatitis B virus (HBV) DNA. By using both techniques along with the examination of hepatitis C virus (HCV) infection, the causes of chronic liver diseases with negative HBsAg were studied. It is found that nested-PCR can increase the sensitivity of single PCR more than 1,000 fold and multiple cloned antibody capture-PCR can detect concentration of HBV DNA as low as 0.1-0.01 pg/L. HBV DNA positive patients were found in 45.5%, 30.8%, 13.3% and 100% respectively of the patients suffering from liver cirhosis with negative HBsAg (group A, 22 cases), chronic hepatitis with negative HBsAg (group B, 13 cases), normal subjects with negative HBsAg and positive hepatitis B core antibody (HBcAb, group C, 30 cases) and liver cirhosis with positive HBsAg and negative HBeAg (group D, 12 cases). HBV DNA can be also found in the serum of HBsAb positive patients and subjects supposed to be healthy, 81.8% and 53.8% of the patients were infected with HBV and/or HCV in group A and group B respectively. All these results suggest that nested-PCR and multiple cloned antibody capture-PCR are rapid and highly sensitive methods for detection of serum HBV DNA. HBV infection is an important cause of chronic liver diseases in patients with negative HBsAg. The causes of most of the HBsAg-negative chronic liver diseases are related with infection of viruses. The clinical significance of serum HBsAb in naturally infected patients should be reconsidered.

[Establishment of labeled primer reverse transcription in situ polymerase chain reaction and detection of hepatitis C virus in liver tissues]

OBJECTIVES

To establish bio-11-photosoralen (BP) labeled primer reverse transcription in situ polymerase chain reaction (RT-in situ PCR), and detect the location and distribution of hepatitis C virus in 17 cases liver tissue embedded by paraffin.

METHODS

The method was compared with indirect RT-in situ PCR and in situ hybridization for detecting hepatitis C virus (HCV) RNA.

RESULTS

The results of serum HCV PCR and southern blot showed that BP labeled primer PCR not only is possible, but also has a good specialty. The HCV positive rate was 59% (10/17) by indirect RT-in situ PCR, 53% (9/17) positive specimens were found by BP labeled primer RT-in situ PCR. Statistical analysis revealed that chi 2 volume was 0.12, P > 0.05, the two methods had no dominantl differences. Meanwhile only 24% (4/17) positive signals were seen by in situ hybridization, which was lower than two RT-in situ PCR, chi 2 volume was 3.97 and 4.37 respectively, P < 0.05. Moreover, HCV was mainly located in hepato-plasmas, but positive signals were found in monocytes and cholangiolar epithelia.

CONCLUSIONS

We conclude that both indirect RT-in situ PCR and BP labeled RT-in situ PCR have the good sensitivities and specialties for detecting HCV RNA of liver tissues, and HCV RNA locates not only in hepatocytes, but also in monocytes and cholangiolar epithelia. The results suggested that hepatocytes may be not only replicate location of hepatitis C virus.

[Detection of hepatitis C virus RNA in paraffin embedded liver tissues by in situ PCR]

The new technique of in situ polymerase chain reaction (ISPCR) was used to study hepatitis C virus (HCV). ISPCR and in situ hybridization (ISH) were performed to detect HCV in 7 paraffin embedded liver tissues and 8 para-hepatocellular cancer tissues. The positive rates were 6/7 and 4/8 respectively, significantly higher than results obtained by ISH, which were 3/7 and 1/8 respectively. It also demonstrated that the specificity of ISPCR was better than ISH. HCV RNA was not only found in hepatocyte plasma but also in cholangiolar epithelia and monocytes. We conclude that ISPCR is a sensitive and specific method that can improve the accuracy in diagnosis of HCV.

A moderately repetitive DNA sequence in alfalfa is transcribed in a floral-specific manner

Based on DNA sequence analysis of 5 clones of repetitive DNA from alfalfa (Medicago sativa), we propose the existence of a dispersed middle repetitive element about 3400 bp long with a copy number in the range of 2-3 x 10(3) per haploid genome. The average A+T content of the sequences was 54.6%, compared with 61.4% for the alfalfa genome. Sequence homologies between overlapping regions of the clones ranged from 85 to 89.5% with an average of 86.6%; sequence divergence was due largely to single base pair changes, with deletions or insertions occurring randomly across sequences. An open reading frame (ORF) in one clone, RPE15, contained homologies to cereal prolamin genes and a legumin box was located upstream of the coding region. A Northern blot of RNA from various alfalfa tissues, probed with the above clone containing this ORF, showed an extensive heterodispersed pattern of hybridization in the late stages of flower bud development but in no other tissues.

[Epidemiologic study on the risk factors of postpartum hemorrhage]

The 1:2 matched case-control retrospective study of postpartum hemorrhage (PPH) was undertaken in Suizhou, Hubei Province from 1 January 1990 to 31 December 1991. The subjects consisted of 109 women who had a PPH (blood loss equal to or more than 500 ml) and 218 women whose blood loss at delivery was less than 200 ml. The results showed that multiparity, age younger than 20 or older than 36, long second and third stages of labour, abortion, low income, lack of obstetric care, etc, were identified as risk factors statistically.

Effect of plant genotype on the transformation of cultivated alfalfa (Medicago sativa) by Agrobacterium tumefaciens

The trait for somatic embryogenesis is being introduced sexually into alfalfa (Medicago sativa) breeding populations to facilitate genetic transformation of this crop. Cocultivation experiments were conducted with an agronomically-improved embryogenic clone from one such population as well as with two other embryogenic clones, one of which was the source of the embryogenic trait in the breeding populations. Transgenic plants were produced from the agronomically-improved clone whereas none were produced from the other two clones. Among the 16 transgenic plants analyzed there was a range in both copy number and number of integration sites for the NPT-II gene; those plants regenerated after a prolonged selection phase in vitro generally had the highest numbers in both respects. There was no evidence of sectoral chimerism of the transgene in a subsample of transgenic plants analyzed by PCR.

Metal ion binding to dog osteocalcin studied by 1H NMR spectroscopy

One-dimensional 1H NMR was employed to study the effects of Ca2+ and Lu3+ binding on the apo and calcium-saturated forms of dog bone Gla protein (BGP, osteocalcin). Titration of apo dog BGP with Ca2+ in 20 mM NaCl showed spectral perturbations consistent with the binding of 5 mol equiv of calcium in the NMR slow-exchange limit. The first 2 Ca2+ equiv induced significant conformational changes in the apoprotein, binding cooperatively with a Kd1 approximately 5.0 x 10(-4) M and a Hill coefficient H = 2.3 in 20 mM NaCl. The last 3 equiv bound with a slightly weaker affinity and did not induce significant structural changes. Neither the affinity nor the stoichiometry of calcium binding was significantly altered at 150 mM NaCl. The addition of only 1 Lu3+ equiv to apo dog osteocalcin was sufficient to induce the same spectral perturbations as 2 Ca2+ ions. The addition of 2 Lu3+ equiv to calcium-saturated osteocalcin had little effect on its 1H NMR spectrum, and BGP aggregated at [Lu3+]o/[BGP]o ratios greater than 2 in either the presence or absence of calcium. The spectrum of calcium-saturated osteocalcin was invariant at < or = 55 degrees C (< or = 50 degrees C in 150 mM NaCl), after which the proton resonances shifted to frequencies more characteristic of apo BGP. Saturation with calcium somewhat stabilized the apo dog osteocalcin protein against conformational changes induced at pH extremes; apo BGP was stable at 6.0 < or = pH < or = 10, and calcium-saturated BGP was stable at 5.8 < or = pH < or = 10. Both our NMR and gel filtration data indicate that calcium-saturated osteocalcin exists as a dimer at both high and low protein concentrations. A conformational change in dog osteocalcin was thus induced by the cooperative association of Ca2+ to two high-affinity sites on the protein and stabilized by the association of 3 additional Ca2+ equiv. The results of our temperature and calcium binding studies were consistent with an estimated Kd1 approximately 5.0 x 10(-4) M for the two high-affinity sites. Lutetium induced the same structural changes in osteocalcin as calcium, but the two high-affinity Ca2+ binding sites did not have equal affinities for Lu3+. The BGP:Ca2+ complex was unstable at the low pH conditions induced by osteoclasts during bone resorption, yet the osteocalcin protein retained a BGP:Ca(2+)-like conformation at low pH. However, unlike the calcium-saturated form of the protein, osteocalcin was monomeric at low pH.

[Chemical constituents of Alyxia levinei Merr]

Three compounds were isolated from the stem and leaves of Alyxia levinei. On the basis of spectrometric analysis and physico-chemical constants they were identified as oleanolic acid, betulin and beta-sitosterol-D-glucoside respectively.