Low-level viremia and virologic failure among people living with HIV who received maintenance therapy with co-formulated bictegravir, emtricitabine and tenofovir alafenamide versus dolutegravir-based regimens

BACKGROUND

Real-world experience with low-level viremia (LLV) and its impact remain less reported among people living with HIV (PLWH) who receive antiretroviral therapy (ART) containing second-generation integrase strand transferase inhibitors (INSTIs), including dolutegravir and bictegravir.

METHODS

Virally suppressed PLWH who had achieved plasma HIV RNA load (PVL) <50 copies/mL for ≥6 months and were switched to either dolutegravir- or bictegravir-based ART were included in this retrospective cohort study. The incidence rates of developing LLV events (PVL, 50-199 copies/mL) and virologic failure (VF) (PVL ≥1000 copies/mL) were compared between the dolutegravir and bictegravir cohorts.

RESULTS

A total of 623 and 862 PLWH switched to dolutegravir-based and bictegravir-based ART, respectively, were included. The incidence rates of developing LLV were 6.2 per 100 person-years of follow-up (PYFU) in the bictegravir cohort and 3.8 per 100 PYFU in the dolutegravir cohort (incidence rate ratio [IRR], 1.63; 95% confidence interval [CI], 0.90-2.95, p=0.08), while the rates of VF were 0.69 per 100 PYFU and 0.95 per 100 PYFU, respectively, in the bictegravir and dolutegravir cohort (IRR, 0.72; 95% CI, 0.12-3.39, p=0.34). Presence of LLV events was not associated with subsequent VF in multivariate analysis. Secondary analysis also demonstrated that resistance-associated mutations (RAMs) to nucleoside reverse-transcriptase inhibitors before switch were not associated with adverse virologic outcomes in either cohort.

CONCLUSIONS

Among virally suppressed PLWH, the incidences of developing LLV or VF were similar after switch to dolutegravir- or bictegravir-based ART. Preexisting RAMs to nucleoside reverse-transcriptase inhibitors or the LLV events were not associated with subsequent VF.

[Safety and efficacy of rotational atherectomy in the interventional treatment of coronary chronic total occlusion lesions]

Objective: To investigate the safety and efficacy of rotational atherectomy in the interventional treatment of coronary chronic total occlusion lesions. Methods: In this retrospective study,a total of 31 consecutive patients with coronary chronic total occlusion(CTO) lesions underwent rotational atherectomy in our hospital from February 2004 to December 2016 were enrolled,and the clinical features were analyzed. Coronary atherectomy was performed if balloon failed to cross the CTO lesions or balloon could not be fully dilated in the CTO lesions after wire crossing. The definition of procedure success was defined as residual stenosis less than 20% after implantation of drug eluting stent and rotational atherectomy. After the procedure, the patients were followed up to observe major adverse cardiac and cerebral vascular events which including cardiogenic death, myocardial infarction, cerebrovascular accident, and target lesion revascularization. Results: The 1.25 mm diameter burr was firstly selected in 80.6% (25/31) patients,and 96.8%(30/31) patients used only 1 burr to complete the rotational atherectomy procedure. The complication rate was 9.8% (3/31) including 1 patient with coronary dissection and 3 patients with slow flow or no flow. There was 1 patent with both coronary dissection and slow flow. The procedure success rate was 96.8%(30/31). Interventional treatment related myocardial infarction occurred in 3 patients during hospitalization.The 30 patients with procedure success were followed up 36(11, 96) months. The incidence rate of major adverse cardiac and cerebral vascular events was 13.3% (4/30), of which the cardiogenic death rate was 3.3% (1/30), the myocardial infarction rate was 6.7% (2/30), cerebrovascular accident rate was 3.3%(1/30),and the target lesion revascularization rate was 6.7% (2/30). Conclusion: Rotational atherectomy is safe and effective in the interventional treatment of coronary CTO lesions.

Biocompatibility study on Ni-free Ti-based and Zr-based bulk metallic glasses

Safety and reliability are crucial issues for medical instruments and implants. In the past few decays, bulk metallic glasses (BMGs) have drawn attentions due to their superior mechanical properties, good corrosion resistance, antibacterial and good biocompatibility. However, most Zr-based and Ti-based BMGs contain Ni as an important element which is prone to human allergy problem. In this study, the Ni-free Ti-based and Zr-based BMGs, Ti₄₀Zr₁₀Cu₃₆Pd₁₄, and Zr₄₈Cu₃₆Al₈Ag₈, were selected for systematical evaluation of their biocompatibility. Several biocompatibility tests, co-cultural with L929 murine fibroblast cell line, were carried out on these two BMGs, as well as the comparison samples of Ti6Al4V and pure Cu. The results in terms of cellular adhesion, cytotoxicity, and metallic ion release affection reveal that the Ti₄₀Zr₁₀Cu₃₆Pd₁₄ BMG and Ti6Al4V exhibit the optimum biocompatibility; cells still being attached on the petri dish with good adhesion and exhibiting the spindle shape after direct contact test. Furthermore, the Ti₄₀Zr₁₀Cu₃₆Pd₁₄ BMG showed very low Cu ion release level, in agreement with the MTT results. Based on the current findings, it is believed that Ni-free Ti-based BMG can act as an ideal candidate for medical implant.

CXCL12 G801A polymorphism and susceptibility to glioma: a case‑control study

Previous studies have demonstrated that the CXCL12 G801A polymorphism is closely correlated with tumor susceptibility. In addition, the CXCL12/CXCR4 pathway is closely related to proliferation, metastasis, and invasion of glioma. However, the genetic effects of the CXCL12 G801A polymorphism on glioma risk in Chinese populations remain unknown. In this study, we investigated the potential associations between the CXCL12 G801A polymorphism with glioma susceptibility and its clinicopathological characteristics. Frequencies of CXCL12 G801A polymorphic variants between glioma patients (N = 750) and healthy controls (N = 750) were assessed using restriction length fragment polymorphism analysis. The association among the CXCL12 G801A polymorphism, glioma grade (WHO classification), and histological type was also evaluated. Our results showed that patients with glioma had significantly higher frequency of the CXCL12-3' A/A genotypes (P = 0.039) as compared with healthy controls. When stratified by the glioma histology, high-grade glioma patients had significantly higher frequency of the CXCL12-3' A/A genotypes (P = 0.019) as compared with low-grade glioma patients. When stratified by the WHO grade, significantly higher frequency of the CXCL12-3' A/A genotype was observed in stage IV glioma patients (P = 0.037). We conclude that the CXCL12 G801A polymorphism is a risk factor that increases susceptibility to gliomas in a subset of the general Han Chinese population.

The lysogenic cycle of the filamentous phage Cflt from Xanthomonas campestris pv. citri

A phage, Cflt, forming turbid plaques, was isolated from Xanthomonas campestris pv. citri. After infection, infected sensitive cells become immune to Cflt and produce very few phages. These properties were genetically rather stable. The phage was purified and shown to be filamentous with a size of 1157 +/- 73 nm. The genome size is about 7.62 kb. The phage does not affect the growth of host bacteria. Under natural cultivation conditions Cflt-lysogenized cells could be induced spontaneously to give high phage yields, or cured to give phage-free cells. The integration of Cflt DNA into host DNA was proved by Southern blot hybridization. The lysogenic phage was genetically stable in log phase cells and persisted in stationary phase cells through many cell generations in the absence of extracellular phage reinfection.

First Report of Lasiodiplodia Fruit Rot of Jackfruit in Taiwan

Jackfruit (Artocarpus heterophyllus Lam.) is a tropical fruit that is native to India. Five diseases, including Rhizopus fruit rot and anthracnose fruit rot, have been recorded in Taiwan (2). In 2003, brown lesions were observed on mature or harvested fruits at the Chiayi Agricultural Experiment Branch. The disease caused fruits to collapse and was easily distinguished from anthracnose and Rhizopus fruit rot. In the field, Rhizopus fruit rot was characterized by black flocci sporangia and mycelia covering the flowers and young fruits. Lasiodiplodia fruit rot often occurred on mature or wounded fruit and diseased fruit were covered with gray or black flat mycelia under humid conditions. In the early stage of Lasiodiplodia fruit rot, tiny yellow-brown lesions appeared on the peel. The lesions could rapidly expand to 10 cm in diameter within 5 days and became dark brown with a light margin. The rot symptoms progressed quickly from the peel surface into the sarcocarps that eventually turned black and soft. A fungus was isolated from the margin of the lesions and cultured on acidified potato dextrose agar (PDA) (pH 3.8). The morphology of the fungus was similar to Lasiodiplodia theobromae (Pat.) Griff. & Maubl. (synonym Botryodiplodia theobromae Pat.), which causes the stem-end rot of mango, papaya, and banana in Taiwan. The fungus grew well and produced pycnidia and conidia on PDA. Young conidia were ovate, hyaline, and thin walled without septa. Mature conidia (20 to 28 × 12 to 15 μm) were dark brown and thick walled with one median septum and longitudinal striations. The internal transcribed spacer (ITS) sequence of ribosomal DNA of this fungus was submitted to GenBank (Accession No. EU 407235) and showed 100% sequence identity with that of Botryosphaeria rhodina (anamorph Lasiodiplodia theobromae; GenBank Accession No. DQ458890). On the basis of morphological and molecular criteria, the fungus was identified as L. theobromae (1). Three healthy jackfruit fruits were wounded and inoculated with 2 × 2 mm mycelial agar plugs of the fungus from a monoconidial culture. A sterile agar plug was placed on the wounded site as a control. The fruits were kept in a box to maintain high humidity for 2 days at room temperature. Brown lesions were observed on all inoculated sites 6 days post infection. The pathogen was reisolated from the lesions of inoculated fruits, fulfilling Koch's postulate. The experiment was repeated twice. To our knowledge, this is the first report of L. theobromae causing fruit rot of jackfruit in Taiwan. References: (1) B. C. Sutton. The Coelomycetes. Commonwealth Mycological Institute, Kew, UK, 1980. (2) Y. P. Tsai, ed. List of Plant Diseases in Taiwan. 4th ed. Taiwan Phytopathological Society, 2002.

The pathology of systemic iridoviral disease in fish

Iridoviruses have been associated with severe disease and economic loss in farmed food fish and ornamental fish, with mortality often reported to reach 50% or more. In the present study, three tropical marine food fish species and four tropical freshwater ornamental fish species with systemic iridovirus infections were examined histopathologically and ultrastructurally. Light microscopy consistently revealed pale to intensely basophilic hypertrophied virus-infected cells in spleen, kidney and intestine from all seven species. Ultrastructural examination showed changes in the vascular endothelium overlying hypertrophied virus-infected cells suggestive of pressure necrosis. Viral isolation was improved by the use of fibroblastic cell lines. This, together with the sub-endothelial location of infected cells in all infected species examined, suggests that systemic iridoviruses are mesotheliotropic.

Chromium (VI) induced oxidative damage to DNA: increase of urinary 8-hydroxydeoxyguanosine concentrations (8-OHdG) among electroplating workers

AIMS

To investigate the concentration of urinary 8-hydroxydeoxyguanosine (8-OHdG) among electroplating workers in Taiwan.

METHODS

Fifty workers were selected from five chromium (Cr) electroplating plants in central Taiwan. The 20 control subjects were office workers with no previous exposure to Cr. Urinary 8-OHdG concentrations were determined using high performance liquid chromatography with electrochemical detection.

RESULTS

Urinary 8-OHdG concentrations among Cr workers (1149.5 pmol/kg/day) were higher than those in the control group (730.2 pmol/kg/day). There was a positive correlation between urinary 8-OHdG concentrations and urinary Cr concentration (r = 0.447, p < 0.01), and urinary 8-OHdG correlated positively with airborne Cr concentration (r = 0.285). Using multiple regression analysis, the factors that affected urinary 8-OHdG concentrations were alcohol, the common cold, and high urinary Cr concentration. There was a high correlation of urinary 8-OHdG with both smoking and drinking, but multiple regression analysis showed that smoking was not a significant factor. Age and gender were also non-significant factors.

CONCLUSION

8-OHdG, which is an indicator of oxidative DNA damage, was a sensitive biomarker for Cr exposure.

Characterization of a novel ranavirus isolated from grouper Epinephelus tauvina

A large icosahedral virus was isolated from diseased grouper Epinephelus tauvina. The virus grew well in several cultured fish cell lines, with stable and high infectivity after serial passages in grouper cell line (GP). The virus was sensitive to both acid and heat treatments. Virus replication was inhibited by 5-iodo-2-deoxyuridine (IUDR), indicative of a DNA-containing genome. The virus infectivity was reduced with ether treatment, suggesting that the virus was lipid-enveloped. Electron micrographs showed abundant cytoplasmic icosahedral virons in the virus-infected GP cells. The size of the intracellular nucleocapsid was 154 nm between the opposite sides, or 176 nm between the opposite vertices with an inner electron-dense core of 93 nm. Virus particles were released through budding from plasma membranes with a size of 200 nm in diameter. SDS-PAGE of purified virus revealed 20 structural protein bands and a major capsid protein (MCP) of 49 kDa. A DNA fragment of approximately 500 nucleotides was successfully amplified by polymerase chain reaction (PCR) using the primers from conserved regions of the MCP gene of frog virus 3 (FV3), the type species of Ranavirus. Subsequent multiple alignment and phylogenetic analysis showed that the newly isolated grouper virus was closely related to largemouth bass virus (LMBV), FV3 and Regina ranavirus (RRV). Our data suggests that the virus isolate is a novel member of genus Ranavirus, family Iridoviridae. We tentatively name the virus as Singapore grouper iridovirus (SGIV). SGIV was able to cause serious systemic disease capable of killing 96% of grouper fry.

Telomerase activity in human bladder tumors and bladder washing specimens

Telomerase appears to be an important factor for the control of cellular proliferation and tumorigenesis. Enzyme activity dramatically increases in almost all human tumors. The purpose of our study was to evaluate the role of telomerase activity as a marker for bladder cancer diagnosis and follow-up. By using the PCR-ELISA based on the TRAP (telomerase repeat amplification protocol) method, telomerase activity of bladder tumors (n = 77), normal-appearing adjacent tissues (n = 21) and bladder washings (n = 37) were analyzed. Telomerase activity was detected in 87% (67/77) of cancer tissues and in 38% (8/21) of normal-appearing adjacent tissues. However, the levels of enzyme activity were significantly higher in cancer tissues than in normal-appearing adjacent tissues (p < 0.05). Telomerase activity in bladder cancer tissues was not correlated to the tumor stage or grade. During a 26 months follow-up period, disease progression occurred in 66.7% of patients with invasive tumors where telomerase activity of the normal-appearing adjacent tissue was detectable, as compared to only 14.3% for patients who showed undetectable telomerase activity in adjacent, normal-appearing tissues (p = 0.094). When telomerase activity of bladder washing fluid was compared with its corresponding tumors, sensitivity of detection was 81% and specificity was 75%. In contrast, urine cytology only yielded a sensitivity of 31% in the detection of cancer. The detection ability between telomerase activity measurement in washing fluid and cytological examination had a trend toward the telomerase measurement identifying more cancer cases than the cytologic examination (p = 0.07). In conclusion, telomerase activity is present in early-stage bladder cancer and is a potential molecular marker for bladder tumors diagnosis. The expression of telomerase activity in normal-appearing mucosa adjacent to bladder tumor is probably an indicator of disease progression. Using the telomerase activity to detect exfoliated cells in bladder washing fluids could be a useful method in adjunct to urine cytology and cystoscopy in establishing the diagnosis and follow-up of bladder cancer.

Multiple transcripts of the CYP21 gene are generated by the mutation of the splicing donor site in intron 2 from GT to AT in 21-hydroxylase deficiency

Maturation of primary RNA transcripts of eukaryotic genes often involves the removal of introns and joining of exons. The fidelity of RNA splicing is dependent on the identity of the nucleotide (nt) sequences at exon/intron boundaries. Most importantly, the highly conserved intronic 5'GT and 3'AG sequences are essential for correct splicing. Substitution of GT by any other nt leads to incomplete mRNA and a disruption of protein structure. We describe here the results of our transfection experiments in COS-1 cells with a CYP21 genomic construct that contained an IVS 2+1G-->A mutation. Analysis of the transcripts by RT-PCR revealed that two different transcripts were generated by this mutant genome. In all the splicing products, we found that the entire exon 2 was deleted. Surprisingly, 30% of the transcripts from this mutant CYP21 genome were accompanied by an inclusion of 3' intron 2 sequences due to the use of a different splice acceptor site. This is the first report of the molecular characterization of a splice donor site mutation in CYP21 via transcription in COS-1 cells.

Prevalence, incidence, and mortality of PD: a door-to-door survey in Ilan county, Taiwan

BACKGROUND

The reported prevalence and incidence rates of PD were significantly lower in China than those in Western countries. People in China and Taiwan have a similar ethnic background.

OBJECTIVE

To investigate the prevalence, incidence, and mortality rate of PD in Taiwan.

METHOD

The authors conducted a population-based survey using a two-stage door-to-door approach for patients aged 40 years or older in Ilan, Taiwan. Patients were diagnosed with PD by having at least two of the four cardinal signs of parkinsonism and exclusion of seconddary parkinsonism. To identify new cases of PD after the survey, patients with negative results of parkinsonism in the first stage were matched to the information on clinical diagnosis of PD from the Bureau of National Health Insurance toward the end of December 31, 1997. All cases of PD were linked to the Taiwan mortality registration to ascertain causes of deaths until December 31, 1999.

RESULTS

The participation rate was 88.1% among the 11,411 contacted individuals. Thirty-seven cases of PD were identified. The age-adjusted prevalence rate of PD for all age groups was 130.1 per 100,000 population after being adjusted to the 1970 US census, assuming no cases of PD would be found among those younger than 40 years of age. Of 9972 non-PD subjects in the first screen, 15 new cases of PD were ascertained. The age-adjusted incidence rate was 10.4 per 100,000 population for all age groups. The case fatality rate of PD after a 7-year follow-up was 40.4% (21 deaths in 52 patients with PD). The relative risk of death for PD cases versus non-PD cases was 3.38 (95% CI: 2.05-4.34). The 5-year cumulative survival rate in PD cases (78.85%) was statistically lower than that in non-PD cases (92.84%).

CONCLUSION

The prevalence and incidence rates of PD in Taiwan were much higher than those reported in China, but closer to those in Western countries. These results suggest that environmental factors may be more important than racial factors in the pathogenesis of PD.

The influence of different sub-type delta opioid receptors in nerve growth factor-induced neuronal differentiation in rat pheochromocytoma PC12 cell

The impairment of neuronal differentiation for long-term opioid drug-exposed infants is a serious problem and there are several speculated mechanisms. We have previously reported that altering the endogenous delta opioid receptor by long-term interaction with its antagonist augmented the nerve growth factor (NGF)-induced neuronal differentiation of rat pheochromocytoma PC12 cells. In this study using subtype-specific antagonist, we present data showing further that type 2 delta opioid receptor (delta(2)-DOR) is the receptor on the PC12 cells participating in the progression of neuronal differentiation upon NGF-stimulation. Unlike the delta(2)-DOR, alteration of type 1 DOR (delta(1)-DOR) activity by delta(1)-DOR-specific antagonist appeared to be toxic for the PC12 cells. The different influence of the subtypes of delta opioid receptors in the neuronal differentiation of the PC12 cells suggests that each subtype of opioid receptor may trigger different biological activities in vivo.

Identification and analysis of a new hepadnavirus in white storks

We identified, cloned, and functionally characterized a new avian hepadnavirus infecting storks (STHBV). STHBV has the largest DNA genome of all avian hepadnaviruses and, based on sequence and phylogenetic analysis, is most closely related to, but distinct from, heron hepatitis B virus (HHBV). Unique for STHBV among the other avian hepadnaviruses is a potential HNF1 binding site in the preS promoter. In common only with HHBV, STHBV has a myristylation signal on the S and not the preS protein, two C terminally located glycosylation sites on the precore/core proteins and lacks the phosphorylation site essential for the transcriptional transactivation activity of duck-HBV preS protein. The cloned STHBV genomes were competent in gene expression, replication, and viral particle secretion. STHBV infected primary duck hepatocytes very inefficiently suggesting a restricted host range, similar to other hepadnaviruses. This discovery of stork infections unravels novel evolutionary aspects of hepadnaviruses and provides new opportunities for hepadnavirus research.

Generation of stable mRNA fragments and translation of N-truncated proteins induced by antisense oligodeoxynucleotides

Binding of phosphorothioate-modified antisense oligodeoxynucleotides (AS ODNs) to target mRNAs is commonly thought to mediate RNA degradation or block of translation. Here we demonstrate cleavage of target mRNAs within the AS ODN binding region with subsequent degradation of the 5' but not the 3' cleavage product. Some, if not all, 3' mRNA fragments lacked a 5' cap structure, whereas their poly(A) tail length remained unchanged. Furthermore, they were efficiently translated into N-terminally truncated proteins as demonstrated in three settings: production of shortened hepadnaviral surface proteins, alteration of the subcellular localization of a fluorescent protein, and shift of the transcription factor C/EBPalpha isoform expression levels. Thus, AS treatment may result in the synthesis of N-truncated proteins with biologically relevant effects.

Electron microscopic observations of a marine fish iridovirus isolated from brown-spotted grouper, Epinephelus tauvina

The morphogenesis and the ultrastructure of a marine fish iridovirus isolated from diseased grouper, Epinephelus tauvina were studied by electron microscopy. The virus was grown on a marine fish cell line (GP) at 25 degrees C. After appearance of advanced cytopathic effect (CPE), various morphogenetic stages of virus amplification, maturation and assembly were detected in the cytoplasm of virus-infected cells. The matured nucleocapsids were probably formed by insertion of electron-dense core material into a partly forming empty capsid just before completely sealed. The nucleocapsids were located at the assembly sites as pseudocrystalline arrays or scattered individually. In the late phase of infection, the nucleocapsids were enveloped and released by budding from the plasma membrane. The budding virus particles could directly enter neighbouring cells by endocytosis to start the next round infection. Ultrastructure of the grouper iridovirus was studied using the methods of enzymatic digestions and detergent degradations. The purified iridovirus particles showed a three-layered membrane including an external lipoprotein envelope, an inner periodic protein capsid and a lipid-containing membrane. The regular array of surface capsid subunits was observed after degradation with detergent.

In vivo gene delivery into ocular tissues by eye drops of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) polymeric micelles

The primary objective of this study was to investigate the feasibility of using PEO-PPO-PEO non-ionic copolymeric micelles as a carrier for eye-drop gene delivery of plasmid DNA with lacZ gene in vivo. Using pyrene fluorescence probe methods, zeta potential, and dynamic light scattering test (DLS), the ability of micelle formation of these block copolymers with plasmid was studied. Gene expressions were visualized by both the quality of enzymatic color reaction using X-gal staining and by the quantification of the substrate chlorophenol red galactopyranoside (CPRG) in enucleated eyes on day 2 after gene transfer. In addition, microscopy to identify the types of cell showing uptake and expression of the transferred gene was used. We found that the block polymeric micelles were formed above 0.1% (w/v) of block copolymer with a size of 160 nm and a zeta potential of -4.4 mV. After 2 days of topically delivery three times a day, the most intense gene expression was observed on days 2 and 3. Reporter expression was detected around the iris, sclera, conjunctiva, and lateral rectus muscle of rabbit eyes and also in the intraocular tissues of nude mice upon in vivo topical application for 48 h with a DNA/polymeric micelle formulation. Furthermore, after two enhancement treatments, the transport mechanisms of the block copolymeric micelles were found through endocytosis in tissues by enhancement through the tight junction pathway. Thus, efficient and stable transfer of the functional gene could be achieved with PEO-PPO-PEO polymeric micelles through topical delivery in mice and rabbits. These in vivo experiments indicate the possible potential use of block copolymers for DNA transfer.

Antibody to the nonstructural protein NS1 of Japanese encephalitis virus: potential application of mAb-based indirect ELISA to differentiate infection from vaccination

An indirect enzyme-linked immunosorbent assay (ELISA) was developed to detect and differentiate the antibody responses to Japanese encephalitis (JE) virus nonstructural protein NS1 between infected and vaccinated individuals. The results showed that all convalescent sera from JE patients contained NS1-specific IgG antibodies, while 65 and 40% of these sera showed detectable NS1-specific IgM and IgA antibodies, respectively. Specificity analysis showed that NS1-specific IgM and IgA antibodies from JE patients do not cross-react to dengue virus NS1 glycoprotein, while IgG antibodies from 10% of JE patients showed significant cross-reaction to dengue virus NS1 glycoprotein. To differentiate infection from vaccination, the immune sera from 24 children vaccinated with inactivated JE vaccine were analyzed. The data showed that none of these immune sera had detectable NS1-specific IgG antibodies. The results demonstrated the potential application of JE NS1-specific indirect ELISA to differentiate infection from vaccination.

Duck hepatitis B virus expresses a regulatory HBx-like protein from a hidden open reading frame

Duck hepatitis B viruses (DHBV), unlike mammalian hepadnaviruses, are thought to lack X genes, which encode transcription-regulatory proteins believed to contribute to the development of hepatocellular carcinoma. A lack of association of chronic DHBV infection with hepatocellular carcinoma development supports this belief. Here, we demonstrate that DHBV genomes have a hidden open reading frame from which a transcription-regulatory protein, designated DHBx, is expressed both in vitro and in vivo. We show that DHBx enhances neither viral protein expression, intracellular DNA synthesis, nor virion production when assayed in the full-length genome context in LMH cells. However, similar to mammalian hepadnavirus X proteins, DHBx activates cellular and viral promoters via the Raf-mitogen-activated protein kinase signaling pathway and localizes primarily in the cytoplasm. The functional similarities as well as the weak sequence homologies of DHBx and the X proteins of mammalian hepadnaviruses strongly suggest a common ancestry of ortho- and avihepadnavirus X genes. In addition, our data disclose similar intracellular localization and transcription regulatory functions of the corresponding proteins, raise new questions as to their presumed role in hepatocarcinogenesis, and imply unique opportunities for deciphering of their still-enigmatic in vivo functions.

Dengue NS1-specific antibody responses: isotype distribution and serotyping in patients with Dengue fever and Dengue hemorrhagic fever

To understand the antibody responses to dengue (DEN) nonstructural 1 (NS1) glycoprotein and their roles in protective immunity or pathogenesis of dengue fever (DF) and dengue hemorrhagic fever (DHF), we have analyzed the NS1-speccific IgM, IgA and IgG antibodies from patients with DF and DHF. An isotype-specific, indirect enzyme-linked immunosorbent assay (ELISA) was established by coating a NS1-specific monoclonal antibody (MAb), D2/8-1, to capture soluble NS1 antigens secreted in the culture supernatants of Vero cells infected with DEN virus. We observed strong anti-NS1 antibody responses in all of the convalescent sera of patients with DF and DHF. Similar NS1-specific isotypic and serotypic antibody responses were found in the sera from DF and DHF patients. The results showed that all DEN infections induced significant NS1-specific IgG, whereas 75% and 60% of primary DF patients vs. 40% and 90% of secondary DF patients produced IgM and IgA antibodies, respectively. Specificity analysis showed that DEN NS1-specific IgG and IgA antibodies cross-react strongly to Japanese encephalitis (JE) virus NS1 glycoprotein, whereas DEN NS1-specific IgM antibodies do not cross-react to JE virus NS1 glycoprotein at all. The serotype specificity of NS1-specific IgM, IgA and IgG were found to be 80%, 67% and 75% for primary infections, and 50%, 22% and 30% for secondary infections in positive samples of DF patients. Similar pattern was found in DHF patients. The results showed that all of the DF and DHF patients produced significant NS1-specific antibodies. We did not observe direct correlation between the anti-NS1 antibody responses and DHF because sera from patients with DF and DHF showed similar anti-NS1 antibody responses.

Two new gene cassettes, dfr17 (for trimethoprim resistance) and aadA4 (for spectinomycin/streptomycin resistance), inserted in an Escherichia coli class 1 integron

Two new gene cassettes, dfr17 and aadA4, inserted in a class 1 integron of Escherichia coli EC107, are described here. The dfr17 cassette encodes trimethoprim resistance and has 91% identity with the dfrVII dihydrofolate reductase gene. The aadA4 cassette confers resistance to spectinomycin and streptomycin and shows 94% identity with the aadA3 gene. The integron carrying the dfr17 and aadA4 cassettes was located on a conjugative plasmid, pEC1072.

Genetic alterations of the p16 gene in urothelial carcinoma in Taiwanese patients

OBJECTIVE

To measure changes in the p16 gene (MTS1, a negative regulator of cell-cycle progression at the G1 checkpoint, and a tumour suppressor gene) in urothelial carcinomas (including upper tract urothelial and bladder tumours), and to correlate these measurements with the clinical status of such patients in Taiwan, where renal pelvic tumours comprise 47% of all kidney tumours and are more common than the average worldwide.

MATERIALS AND METHODS

Thirty-five upper tract urothelial and 61 bladder tumours were examined for changes in p16. Deletion of the gene was assessed by Southern blot analysis and mutation analysed using polymerase chain reaction-single strand conformation polymorphism, followed by direct sequencing.

RESULTS

Of the 61 bladder carcinomas, homozygous deletion of p16 was detected in 12 (20%). However, a homozygous deletion was detected in 11 of 35 (31%) upper tract urothelial carcinomas, a higher frequency than that reported for transitional cell bladder carcinomas. Deletion was detected as frequently in stage I tumours as in late-stage tumours, suggesting that p16 deletion is a relatively early event in urothelial tumorigenesis. No point mutations were noted for p16 in any of the primary urothelial tumours. Most multiple and recurrent tumours and metastatic nodules in individual patients contained identical p16 genetic lesions, confirming that the tumours were probably monoclonal. In addition, there was a high gene dose of p16 in bladder carcinomas from patients with lymph node metastasis.

CONCLUSION

Deletion of p16 appears to be a common event in urothelial carcinomas, especially in upper tract urothelial tumours. High levels of p16 were detected in tumours with lymph node metastasis. It seems likely that a high p16 level is associated with carcinomas of advanced stage and grade, and with poor prognosis in patients with such cancers.

A new avian hepadnavirus infecting snow geese (Anser caerulescens) produces a significant fraction of virions containing single-stranded DNA

We describe the identification and functional analysis of an evolutionary distinct new avian hepadnavirus. Infection of snow geese (Anser caerulescens) with a duck hepatitis B virus (DHBV)-related virus, designated SGHBV, was demonstrated by detection of envelope proteins in sera with anti-DHBV preS and S antibodies. Comparative sequence analysis of the PCR-amplified SGHBV genomes revealed unique SGHBV sequence features compared with other avian hepadnaviruses. Unlike DHBV, SGHBV shows an open reading frame in an analogous position to orthohepadnavirus X genes. Four of five cloned genomes were competent in replication, gene expression, and virus particle secretion in chicken hepatoma cells. Primary duck hepatocytes were permissive for infection with SGHBV, suggesting a similar or identical host range. SGHBV was found to secrete a significant fraction of virion-like particles containing single-stranded viral DNA. This was observed both in cell culture medium of SGHBV DNA-transfected LMH cells and in viremic sera of several birds, suggesting that it is a stable trait of SGHBV. Taken together, SGHBV has several unique features that expand the knowledge of the functional and evolutionary diversity of hepadnaviruses and offers new experimental opportunities for studies on the life cycle of hepadnaviruses.

Detailed characterization of the binding site of the lipoprotein lipase-specific monoclonal antibody 5D2

Monoclonal antibody (MAb) 5D2 recognizes lipoprotein lipases (LPL) from different species but not related lipases. This MAb is a unique reagent, used world-wide, because it differentiates between monomeric inactive and dimeric active LPL, inhibits human LPL enzyme activity, and binds to C-terminal LPL sequences involved in interactions with lipoproteins, lipoprotein receptors, and heparin. In this study we have analyzed the fine specificity of the MAb epitope recognition in order to better understand its functional properties and species-specific LPL immune reactivity. In peptide scan assays, MAb 5D2 reacted with all, except two, 13 amino acid-long peptides located between positions 380 and 410. Peptides from the amino terminal end of this region reacted more strongly than those from the carboxyl terminal end. Furthermore, only a peptide from the amino terminal end competed effectively with the binding of MAb 5D2 to native LPL bound to microtiter plates or nitrocellulose. A systematic peptide mutagenesis study indicated that 8 amino acids of the reactive region, mainly located in the amino terminal end, are critical for binding and probably directly interact with MAb 5D2. The experimentally determined antigenicities of species-specific LPL peptides and of the corresponding denatured full-length LPL proteins on immunoblots were consistent with these findings. According to a proposed 3D-model for LPL, only the amino terminal end of the antigenic region is easily surface-accessible. These data combined with 3D-modelling of monoclonal antibody (MAb)-lipoprotein lipase (LPL) protein interaction provide new insight into the known biological effects of MAb 5D2 on LPL and the antigenic determinants that are recognized.

Assaying for structural variation in the parvovirus capsid and its role in infection

The capsid of canine parvovirus (CPV) was assayed for susceptibility to proteases and for structural variation. The natural cleavage of VP2 to VP3 in CPV full (DNA containing) particles recovered from tissue culture occurred within the sequence Arg-Asn-Glu-Arg Ala-Thr. Trypsin, chymotrypsin, bromelain, and cathepsin B all cleaved >90% of the VP2 to VP3 in full but not in empty capsids and did not digest the capsid further. Digestion with proteinase K, Pronase, papain, or subtilisin cleaved the VP2 to VP3 and also cleaved at additional internal sites, causing particle disintegration and protein degradation. Several partial digestion products produced by proteinase K or subtilisin were approximately 31-32.5 kDa, indicating cleavage within loop 3 of the capsid protein as well as other sites. Protease treatment of capsids at pH 5.5 or 7.5 did not significantly alter their susceptibility to digestion. The isoelectric point of CPV empty capsids was pH 5.3, and full capsids were 0.3 pH more acidic, but after proteolysis of VP2 to VP3, the pI of the full capsids became the same as that of the empty capsids. Antibodies against various capsid protein sequences showed the amino termini of most VP2 molecules were on the outside of full but not empty particles, that the VP1-unique sequence was internal, and that the capsid could be disintegrated by heat or urea treatment to expose the internal sequences. Capsids added to cells were localized within the cell cytoplasm in vesicles that appeared to be lysosomes. Microinjected capsids remained primarily in the cytoplasm, although a small proportion was observed to be in the nucleus after 2 h. After CPV capsids labeled with [35S]methionine were bound to cells at 0 degrees C and the cells warmed, little cleavage of VP1 or VP2 was observed even after prolonged incubation. Inoculation of cells with virus in the presence of proteinase inhibitors did not significantly reduce the infection.

The negative influence of endogenous opioid receptor activity on the differentiation of the rat pheochromocytoma PC12 cells induced by nerve growth factor

We determined the effect of naloxone and morphine on the differentiation of pheochromocytoma cell, the PC12 cells, induced by nerve growth factor (NGF). PC12 cells were grown in medium containing NGF with or without the addition of naloxone or morphine for up to 10-day treatments. NGF-induced morphological differentiation of PC12 cells was manifested by an increase in the percentage of differentiated cells and the average length of neurite per cell. Co-addition of morphine with NGF did not affect both parameters as compared to that of NGF alone. On the contrary, co-addition of naloxone with NGF significantly increased the percentage of differentiated cells, but did not affect the outgrowth of neurites. This effect of naloxone was reversed by the addition of morphine, suggesting that naloxone produced its effect by inhibiting the endogenous activity of opioid receptor. This study indicates a significant functional role of opioid receptor in NGF-induced differentiation of PC12 cells.

The suppression effect of DNA sequences within the C4A region on the transcription activity of human CYP21

Two CYP21 genes, the active CYP21 and the pseudogene, CYP21P, also pairs of duplicated genes including the XA, XB, XB-S; YA, YB; and ZA, ZB are arranged in tandem next to the serum complement C4 genes (C4A and C4B). In this report, we have analyzed the influence of some DNA sequences within the C4A/CYP21P region on the transcription activity of the human CYP21. After transiently transfecting the plasmid constructs into mouse adrenocarcinoma Y1 cells, mouse testis Leydig tumor MA10 cells and human liver tumor HepG2 cells, our results showed that sequences located within the -13943/-13174 and -3278/-2586 regions upstream from the CYP21P had suppression effects on the promoter activity of human CYP21. However, the short sequences spanning from -8415/-8373 and -4511/-4140 upstream from the CYP21P did not alter the basal transcription activity of the CYP21 gene. Our results indicated that specific sequences within the C4A region might function as suppressor-like elements for the transcription of human CYP21.

Diagnostic pitfalls of Merkel cell carcinoma and dramatic response to chemotherapy

Merkel cell carcinoma (MCC) is an unusual malignant tumor that arises from neuroendocrine cells with features of epithelial differentiation. We describe a MCC patient with unusual clinical, histopathological, and immunohistochemical features. Although the microscopic, immunohistochemical, and ultrastructural characteristics of MCC have been well defined, diagnostic difficulties remain, particularly in distinguishing it from lymphoma involving the skin, as suggested by our case. This is an unusual case in which dense lymphoid infiltration masked the true tumor. All the immunohistochemical markers of MCC except neuron-specific enolase (NSE) were negative. The dramatic response to primary chemotherapy was also very noteworthy.

The -104G nucleotide of the human CYP21 gene is important for CYP21 transcription activity and protein interaction

CYP21 gene encodes the steroid 21-hydroxylase (P450c21) that is involved in steroidogenesis in the adrenal cortex. Mutations occurring on CYP21 which convert it to the neighboring pseudogene, CYP21P, are found in patients with congenital adrenal hyperplasia (CAH), an autosomal recessive disease. We previously reported that the CYP21P pseudogene had lower transcription activity when compared with the active CYP21 gene. The sequences determining the basal transcription activity of the human CYP21 gene are located within the 166 bp region upstream from the transcriptional start site. Within this region, only 4 nucleotides are different between the active CYP21 and the CYP21P pseudogene; they are located at the -117, -104, -101 and -94 positions from the start site of the gene. Here, we report that the CYP21 gene-specific G nucleotide sequence at the -104 position is required for its basal transcription activity driven by the native TATA box of the human CYP21 gene. When this single nucleotide is changed to the CYP21P sequence, the basal transcription activity decreases by approximately 80% in transient transfection assay. In addition, our data from gel retardation assay show that this sequence is also critical for interaction with nuclear proteins from adrenal cells. These results therefore suggest that the single G sequence of the human CYP21 gene is crucial for the expression of its basal transcription activity, and this may be influenced by the interaction with specific nuclear proteins from the adrenal gland.

Surveillance of noise-induced hearing loss in Taiwan, ROC: a report of the PRESS-NHL results

BACKGROUND

To understand the extent of noise-induced hearing loss (NIHL) among noise-exposed workers, an ongoing public health surveillance system (Program to Reduce Exposure by Surveillance System or PRESS-NIHL) was established in Taiwan in 1995 to monitor the prevalence of NIHL.

METHODS

A total of 9,535 noise-exposed (> 85 dBA) workers were recruited into PRESS-NIHL from January to June 1995. Each received a periodic annual audiometric examination at 1 of 73 well-qualified audiometric examination rooms in accredited hospitals. Among those examined, 9,463 audiograms were acceptable for evaluation to determine the severity of NIHL at 4K Hz.

RESULTS

The mean hearing threshold at 4K Hz was 36.8 dB among male workers and 29.7 dB among female workers. The mean hearing loss at 4K Hz of male workers was higher than that of female workers. Among both men and women, hearing ability was found to decrease with increasing age. A total of 3,216 (34.0%) workers were found to have NIHL, with a hearing threshold higher than 40 dB (NIHL) in either one or both ears. Among these workers, 1,886 (19.9%) had mild NIHL (hearing threshold between 40 and 55 dB) and 1,330 (14.1%) had severe NIHL (hearing threshold above 55 dB) in either one or both ears. The proportion of severe NIHL was higher in certain industries, including construction (38.6%), ship building/repairing (19.2%), and weapon manufacturing (13.6%).

CONCLUSION

This surveillance system for NIHL is on of the first surveillance systems in the world established to monitor and control NIHL in the setting of industrial hygiene and occupational disease prevention. Our finding of a high prevalence of NIHL in certain industries will trigger immediate actions to control noise hazard, which in turn will provide better protection for noise-exposed workers.

Hepatitis B virus X protein and p53 tumor suppressor interactions in the modulation of apoptosis

We have reported previously that the hepatitis B virus oncoprotein, HBx, can bind to the C terminus of p53 and inhibit several critical p53-mediated cellular processes, including DNA sequence-specific binding, transcriptional transactivation, and apoptosis. Recognizing the importance of p53-mediated apoptosis for maintaining homeostasis and preventing neoplastic transformation, here we further examine the physical interaction between HBx and p53 as well as the functional consequences of this association. In vitro binding studies indicate that the ayw and adr viral subtypes of HBx bind similar amounts of glutathione S-transferase-p53 with the distal C terminus of HBx (from residues 111 to 154) being critical for this interaction. Using a microinjection technique, we show that this same C-terminal region of HBx is necessary for sequestering p53 in the cytoplasm and abrogating p53-mediated apoptosis. The transcriptional transactivation domain of HBx also maps to its C terminus; however, a comparison of the ability of full-length and truncated HBx protein to abrogate p53-induced apoptosis versus transactivate simian virus 40- or human nitric oxide synthase-2 promoter-driven reporter constructs indicates that these two functional properties are distinct and thus may contribute to hepatocarcinogenesis differently. Collectively, our data indicate that the distal C-terminal domain of HBx, independent of its transactivation activity, complexes with p53 in the cytoplasm, partially preventing its nuclear entry and ability to induce apoptosis. These pathobiological effects of HBx may contribute to the early stages of hepatocellular carcinogenesis.

Allelic loss at BRCA1, BRCA2, and adjacent loci in relation to TP53 abnormality in breast cancer

Cells with abnormal TP53 lose cell cycle checkpoints, resulting in genomic instability and neoplastic transformation. However, the evidence linking the tumor-specific targets of genomic alteration to an abnormal TP53 is limited. The present study tested the hypothesis that TP53 abnormalities are correlated with an increased frequency of deletion of breast cancer susceptibility loci (17q and 13q) in breast carcinomas. Tumors from 90 patients were examined for TP53 abnormality and loss of heterozygosity (LOH) at 11 loci on 17q (17q11.2-21) and 13q (13q12-14), including the loci for BRCA1 and BRCA2. A higher frequency of LOH was consistently found at 17q or 13q loci in tumors with an abnormal TP53. The increased LOH in relation to TP53 abnormality was statistically significant at the BRCA1, D17S588, and D13S267 loci (P < 0.05) but not at the locus for BRCA2 (P = 0.64). These observations imply a possible link between an abnormal TP53 and specific genomic deletions of breast cancer susceptibility loci, which may provide clues to the role of TP53 during breast tumorigenesis.

Pharmacokinetics and dose proportionality of beclomethasone from three strengths of a CFC-free beclomethasone dipropionate metered-dose inhaler

As part of a development program to offer alternatives to chlorofluorocarbon (CFC) containing metered-dose inhalers, beclomethasone dipropionate has been formulated in a CFC-free system at three strengths: 50, 100, and 200 micrograms/actuation ex valve. To measure serum levels and dose proportionality of the beclomethasone derived from beclomethasone dipropionate, 13 mild to moderate asthmatic patients received a single dose of eight inhalations from each strength according to a double-blind crossover design. Seven patients were studied over 4 h and six patients over 12 h. For the total doses of 400, 800, and 1600 micrograms studied over 12 h, Cmax and AUC increased in a ratio of 1:1.8:3.1. A good correlation was seen between the fine-particle mass delivered and the in vivo performance of the three strengths. From a clinical point of view, the predictable increases in serum levels with an increase in dose will permit the clinician to effectively titrate a patient with this product.

Dose-response relationship between prevalence of cerebrovascular disease and ingested inorganic arsenic

BACKGROUND AND PURPOSE

Circulatory diseases such as ischemic heart disease and peripheral vascular disease induced by long-term arsenic exposure have been well documented in previous studies, but the dose-response relationship between cerebrovascular disease and ingested inorganic arsenic remains to be elucidated. The prevalence of cerebrovascular disease among residents of the Lanyang Basin on the northeast coast of Taiwan was surveyed to examine its association with exposure to arsenic in well water.

METHODS

A total of 8102 men and women from 3901 households were recruited in this study. The status of cerebrovascular disease of study subjects was identified through home-visit personal interviews and ascertained by review of hospital medical records according to the World Health Organization criteria. Information on consumption of well water, sociodemographic characteristics, cigarette smoking, and alcohol consumption habits, as well as personal and family history of diseases, was also obtained. Arsenic concentration in the well water of each household was determined by hydride generation and atomic absorption spectrometry. Logistic regression analysis was used to estimate multivariate-adjusted odds ratios and 95% confidence intervals for various risk factors of cerebrovascular disease.

RESULTS

A significant dose-response relationship was observed between arsenic concentration in well water and prevalence of cerebrovascular disease after adjustment for age, sex, hypertension, diabetes mellitus, cigarette smoking, and alcohol consumption. The biological gradient was even more prominent for cerebral infarction, showing multivariate-adjusted odds ratios of 1.0, 3.4, 4.5, and 6.9, respectively, for those who consumed well water with an arsenic content of 0, 0.1 to 50.0, 50.1 to 299.9, and > 300 micrograms/L.

CONCLUSIONS

Long-term exposure to inorganic arsenic from well water was associated with an increased prevalence of cerebrovascular disease, especially cerebral infarction.

Genetic localization of the type I trimethoprim resistance gene and its dissemination in urinary tract isolates in Taiwan

In a total of 425 urinary isolates of E. coli, Enterobacter spp., and Klebsiella spp. selected, there were 169 (45.4%) isolates harbouring type I dihydrofolate reductase (DHFR) gene among 374 trimethoprim-resistant isolates. In these 169 isolates, only 17.2% hybridized with the Tn7 probe. According to another probe specific for the integrase gene of integron, 87.6% showed a positive reaction. Further analysis by restriction mapping proved that the type I DHFR gene was inserted into a integron-like structure. These results indicate that the type I DHFR gene that was initially observed in association with transposable element Tn7 is becoming associated with an integrase function similar to integrons in most instances. Further analysis of the distribution of Tn21-like integrase gene in clinical isolates indicated that the prevalence rates were 86.4%, 84.8%, and 76.7% respectively in E. coli, Enterobacter spp., and Klebsiella spp.. Furthermore, the integrase gene found in our clinical isolates proved to be mediated by a plasmid, demonstrated by Southern hybridization. Thus, the trimethoprim-resistant gene that developed under selective pressure from the double drug trimethoprim and sulphonamide was transmitted by insertion into integron-like structure and then mediated by plasmid transfer for dissemination.

Genomic deletion and p53 inactivation in cervical carcinoma

The tumor-suppressor gene p53 acts as "the guardian of the genome", sensing DNA damage and initiating protective responses. To examine the hypothesis that p53 abnormality leads to increased genomic alterations in primary tumor cells, our study utilized 51 primary tumors of cervical carcinoma and 10 microsatellite markers. These markers were mapped to the short arms of chromosomes 3 and 5, covering the regions 3p13-25 and 5p15.1-15.3. Genomic deletion on 3p and 5p was correlated with genetic or epigenetic p53 inactivation pathways, including p53 mutation, genetic deletion of p53 and cervical infection with human papillomavirus. The proportion of abnormal p53 was found to be significantly higher in the cases exhibiting loss of heterozygosity (LOH) on 5p (p < 0.001), supporting the hypothesis of the presence of a p53-dependent pathway to cervical tumorigenesis. In contrast, however, LOH on 3p was found to be independent of p53 inactivation. A common deletion region, 3p22-24, was identified in 44% of informative cases, and genomic loss at this specific region was correlated with early tumorigenic onset and poor grade of tumor differentiation. Diversity within the patterns of genomic alteration in the same form of cancer suggests different sets of risk/tumorigenic profiles, molecular pathogenesis, as well as prognosis and outcome.

Structural and functional analysis of the promoter of the hepatic lipase gene

Hepatic lipase (HL) gene transcription is almost exclusively limited to hepatocytes. Here we have studied sequences and transcription factors regulating basal and hepatocyte-restricted HL promoter activity. Sequencing of a cloned 3.4-kb HL promoter fragment revealed three Alu repeat sequences and a consensus hepatocyte-enriched nuclear transcription factor 1 (HNF1) binding site located upstream of one major and one minor transcription initiation site. By transfection of cell lines of hepatic and non-hepatic origin and of primary hepatocyte cultures, sequences controlling basic HL promoter activity and negative elements located downstream and upstream thereof which extinguish or enhance this activity were defined. Some HL-promoter fragments with internal deletions were active only in primary hepatocyte cultures. Human HNF1 protein was shown to bind to the HL-specific HNF1 response element and the activity of a heterologous promoter was enhanced by HL-HNF1 in rat primary hepatocyte cultures but not in the context of the authentic 3.4-kb HL promoter sequences. In cell lines the presence of HNF4 but not of HNF1 and vHNF1 mRNA was found to correlate with HL gene expression although no perfect consensus HNF4 binding motif was detected in the promoter region tested. Taken together, these data indicate that hepatocyte-specific HL gene transcription is controlled by positive and negative transcription regulatory proteins which bind to sequence motifs within and outside of the proximal 3.4-kb promoter fragment studied. For the elucidation of the control of HL promoter activity in vivo the use of primary hepatocyte cultures is essential.

Sequence heterogeneity of heron hepatitis B virus genomes determined by full-length DNA amplification and direct sequencing reveals novel and unique features

So far, only a single heron hepatitis B virus genome (HHBV-4) has been cloned and sequenced. Therefore, neither the significance of its sequence divergence from other avian hepadnaviruses nor the sequence variability of HHBV genomes in general are known. Here we have analysed the sequence heterogeneity of HHBV genome populations in several sera from naturally infected herons. A highly sensitive PCR method for full-length HHBV genome amplification was established which allowed direct sequencing of entire HHBV populations without prior cloning. Sequences of HHBV genomes from four sera were thus obtained which differed from those of HHBV-4 by up to 7%. Some of the divergent nucleotides and the corresponding amino acids of the predicted viral proteins were conserved in all four new HHBV isolates and varied only in HHBV-4. This indicates that the HHBV-4 genome is not in all aspects representative of this class of viruses. Interestingly, a highly conserved ORF upstream of the C-gene present in a position analogous to that of the mammalian hepadnavirus X-gene became apparent in all HHBV genomes. In contrast to the duck hepadnaviruses, the small (sAg-S) instead of the largest (sAg-L) envelope protein of all HHBVs has a myristylation site. These data confirm the significant sequence divergence of HHBV from other avian hepadnaviruses. Moreover, they show that HHBV has low sequence variability and indicate two new and unique features not evident in other avihepadnaviruses: an additional, highly conserved gene and potential myristylation of the sAg-S instead of the sAg-L envelope protein.

Comparative serum estradiol profiles from a new once-a-week transdermal estradiol patch and a twice-a-week transdermal estradiol patch

Two identical open-label, randomized crossover studies were conducted to compare serum estradiol profiles from the new 12.5- and 25-cm2 once-a-week adhesive patches with those from the 10- and 20-cm2 commercially available twice-a-week Estraderm patches when applied as directed during a 1-week patch-wear period. Both studies were conducted in healthy postmenopausal women; serum estradiol levels were determined by gas chromatography/mass spectroscopy (GC/MS). Although both sizes of both patch treatments produced mean serum estradiol levels in the therapeutic range, the once-a-week patch provided more constant mean levels, avoiding large peak-to-trough fluctuations. As expected, the differences in mean serum estradiol concentrations between the two patch treatments occurred during the second application of the twice-a-week patch. Based on these results, the once-a-week drug in adhesive patch appears to be an acceptable means of hormone replacement therapy.

Novel patterns of p53 abnormality in breast cancer from Taiwan: experience from a low-incidence area

Among 114 breast cancers in Taiwan, the prevalence of p53 mutation (22.8%) and p53 accumulation (38.3%) was similar to that in high-incidence areas. However, novel patterns of p53 abnormalities, including unique sites or types of mutation (i.e. an excessive proportion of G:C to A:T transition at CpG site), and accumulation of wild-type p53 either within nuclear or cytoplasmic compartments were noted. These may have relevance to breast cancer in Taiwan, a low-incidence area.

Systemic concentrations of salbutamol and HFA-134a after inhalation of salbutamol sulfate in a chlorofluorocarbon-free system

The objective of this study was to determine if salbutamol was absorbed from a new salbutamol sulfate chlorofluorocarbon (CFC)-free metered-dose inhaler (MDI). Measurement of HFA-134a, the CFC-free propellant, was included to provide proof of delivery of this MDI. Eight healthy men received two inhalations (90 micrograms salbutamol base equivalents per inhalation ex adapter) from the CFC-free inhaler (MDI A) in period 1 and from a reference CFC inhaler (MDI V) in period 2. Eight postdose samples were collected for the determination of salbutamol serum levels over a 4-h period. Salbutamol levels were not quantifiable in most samples. Four subjects given MDI A and two given MDI V had a few transient salbutamol levels, which occurred in the first hour after dosing, within a narrow range of 1-2 ng/ml and close to the lower limit of detection (1 ng/ml). No pharmacokinetic analyses were possible. Blood samples were also collected after MDI A for propellant quantitation. HFA-134a levels were seen in all subjects, verifying absorption. We conclude that the transient salbutamol serum levels can be attributed to the two-inhalation dose and not to either propellant system.

Diagnosis of Castleman's disease by identification of an immunophenotypically aberrant population of mantle zone B lymphocytes in paraffin-embedded lymph node biopsies

Castleman's disease (CD) is characterized by lymph node enlargement due to hyperplasia of abnormal lymphoid follicles and paracortical lymphocytic hyaline vascular (HV) stroma or plasmacytosis (PC). The lymphoid follicles in CD show involuted germinal centers and prominent mantle zone lymphocytes. Ninety-seven cases clinically suspected to be CD were analyzed according to conventional histologic criteria established by Castleman and Keller for diagnosis. Twenty-two cases were excluded as nonspecific hyperplasia (12); Hodgkin's and non-Hodgkin's lymphoma (9); and multiple myeloma involving lymph node paracortex (1). The 75 remaining cases, consisting of 51 cases of CD and 24 with altered follicles or paracortex suggestive of CD, were further analyzed immunohistologically for changes in follicular dendritic reticulum cells (FDRC) using the monoclonal antibody Ki-M4p, for germinal center proliferation with Ki-S5, for mantle zone immunophenotype with Ki-B3 and Ki-B5, for paracortical plasmacytoid monocytes with Ki-M1p, and for plasma cell clonality by applying antibodies to kappa and lambda immunoglobulin light chains. Lymph nodes showing nonspecific follicular and paracortical hyperplasia were included as controls. Hyaline vascular CD and plasma cell CD showed enlarged, polyploid FDRC with prominent nucleoli, decreased germinal center proliferation, and mantle zone populations of immunophenotypically aberrant, Ki-B3-negative B lymphocytes. Thirty-seven percent of hyaline vascular CD and plasma cell CD contained plasmacytoid monocytes, and 15% showed interstitial areas of lambda predominant plasma cells. Plasmacytoid monocytes were common in hyaline vascular CD but rare in plasma cell CD. Cases suspected to be CD that demonstrated a mantle zone population of Ki-B3-negative B lymphocytes had clinical finding of POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal paraprotein, and skin changes or sclerotic bone lesions) syndrome and were reclassified as hyaline vascular CD, plasma cell CD, and mantle zone CD with an aberrant mantle zone immunophenotype only (lacking follicular center and paracortical histologic or immunohistologic abnormalities). Immunohistochemistry was valuable for identification of dysplastic FDRC, decreased germinal center proliferation, and plasmacytoid monocytes. In addition, immunohistochemistry was essential for detection of plasma cell clonality, an aberrant mantle zone immunophenotype, and mantle-zone-restricted CD that was devoid of diagnostic alterations of germinal center or paracortex.

The common I172N mutation causes conformational change of cytochrome P450c21 revealed by systematic mutation, kinetic, and structural studies

We have investigated the structure and function of P450c21 with regard to a conserved site around Ile-172 by site-directed mutagenesis making single amino acid substitutions of residues 169 173. Substitutions of Ile-171 and -172 resulted in production of mutant proteins with dramatic reductions in enzymatic activities, indicating the importance of these two residues in maintaining the structure and function of P450c21. The I171N protein was present at a slightly lower level, due to a decreased rate of protein synthesis. The I172N apoprotein was synthesized at the normal rate, but its heme-bound P450 form was present at a much lower level. This I172N protein was tightly integrated into the membrane of endoplasmic reticulum, similar to the wild type P450c21, as shown by immunofluorescence detection, alkaline extraction, and cellular fractionation. Kinetic studies indicated that I172N had a lower Vmax value. In addition, the I172N protein was more sensitive to proteinase K digestion, indicating a possible alteration of conformation. This conformational change may result in the lower yield of the I172N hemoprotein and the reduced catalytic activity.