Increased glycophorin A somatic cell variant frequency in arsenic-exposed patients of Guizhou, China

Exposure to arsenic through domestic burning arsenic-containing coal causes various tumors in a population of Guizhou, China. The glycophorin A (GPA) assay is a human mutation assay detecting somatic variation in erythrocytes expressing the MN blood type, and was used to assess genotoxicity of arsenic-exposed patients. Peripheral blood was collected from 18 adult healthy subjects and 40 arsenic-exposed patients in heparin-treated tubes. Erythrocytes were isolated, fixed in formalin and immuno-labeled with fluorescent antibodies against GPA, followed by flow cytometry analysis. Arsenic exposure increased the variant frequency (expressed as the number of variant red cells per 10(6) erythrocytes): NN, 3.7 in healthy subjects versus 21.2 in arsenic-exposed patients; N phi, 12.6 versus 33.1; MM, 13.1 versus 110; and M phi, 5.2 versus 20.3. The total GPA variant frequency was increased about five-fold (34.7 in healthy subjects versus 185 in arsenosis patients). Furthermore, the variant frequency was significantly higher in skin tumor-bearing patients: NN, 19.4 in arsenic-exposed non-tumor patients versus 31.5 in tumor-bearing patients; N phi, 29.5 versus 54.5; MM, 102 versus 159; M phi, 15.9 versus 45.1. Total GPA variant frequency in arsenic-exposed patients bearing skin tumors was significantly increased compared to patients without skin tumors (167 versus 290). The relationship between arsenic exposure history and GPA variant frequency was less evident. These data demonstrate that arsenic exposure is associated with mutations at the GPA locus, an effect exaggerated in patients bearing arsenic-induced skin tumors. The variant frequency of GPA could be a useful biomarker for arsenic exposure and arsenic carcinogenesis.

The high integration and differentiation potential of autologous neural stem cell transplantation compared with allogeneic transplantation in adult rat hippocampus

Cell therapy is thought to have a central role in restorative therapy, which aims to restore function to the damaged nervous system. The purpose of this study was to establish an autologous neural stem cell (NSC) transplantation model using adult rats and to compare survival, migration, and differentiation between this system and allogeneic NSC transplantation. Furthermore, we compared the immunologic response of the host tissue between autologous and allogeneic transplantation. NSCs were removed from the subventricular zone of adult Fischer 344 rats using stereotactic methods. NSCs were expanded and microinjected into normal hippocampus in the autologous brain. Allogeneic NSC (derived from adult Wistar rats) transplantation was performed using the same procedure, and hippocampal sections were analyzed immunohistologically 3 weeks post-transplantation. The cell survival and migration rate were higher for autologous transplantation than for allogeneic transplantation, and the neuronal differentiation rate in the autologous transplanted cells far exceeded that of allogeneic transplantation. Furthermore, there was less astrocyte and microglia reactivity in the host tissue of the autologous transplantation compared with allogeneic transplantation. These findings demonstrate that immunoreactivity of the host tissue strongly influences cell transplantation in the CNS as the autologous transplantation did not induce host tissue immunoreactivity; the microenvironment was essentially maintained in an optimal condition for the transplanted cells.

Fertilization by intracytoplasmic sperm injection (ICSI) does not impair subsequent pregnancy outcome following frozen embryo transfer (ET) as determined by a large retrospective analysis

PURPOSE

To determine if fertilization by intracytoplasmic sperm injection (ICSI) adversely affects pregnancy outcome following frozen embryo transfer (ET).

METHODS

Retrospective analysis of frozen ETs where the oocytes were fertilized by conventional insemination vs ICSI was carried out.

RESULTS

No difference in pregnancy outcome was found in women up to age 42. There was a non-significant trend for lower pregnancy rates in women age 43 and older.

CONCLUSIONS

In the largest series to date by far these data convincingly show that fertilization by ICSI does not impair outcome following frozen ET.

A comparison of luteal phase support in graduated estradiol/progesterone replacement cycles using intramuscular progesterone alone versus combination with vaginal suppositories on outcome following frozen embryo transfer

PURPOSE

To compare pregnancy outcome following frozen embryo transfer according to type of progesterone (P) support given in the luteal phase.

METHODS

Retrospective cohort analysis of frozen embryo transfer (ET) cycles in which ovulation was suppressed by graduated estradiol in the follicular phase. Two P regimens in the luteal phase were compared: P vaginal suppositories and intramuscular P vs intramuscular alone.

RESULTS

The clinical and viable pregnancy rates were significantly higher for the women receiving only intramuscular P (57.6% and 43.7%) vs those receiving combined therapy (45.9% and 35.6%, respectively). The implantation rates were not significantly different (22.6% vs 19.5%).

CONCLUSION

The increased pregnancy rates with intramuscular P may have been related to a higher number of embryos transferred (3.69 vs 3.26). Nevertheless, intramuscular P alone is at least as effective, if not more effective, than combined therapy for frozen embryo transfers.

A comparison of in vitro fertilization outcome by culture media used for developing cleavage-stage embryos

PURPOSE

To determine whether removing glucose and phosphate from media used for developing cleavage-stage embryos improves outcome following transfer of fresh or frozen embryos. Furthermore the study would evaluate the efficacy of adding nonessential amino acids and glutamate to media.

METHODS

Embryo development was rotated on a weekly basis in human tubal fluid (HTF), versus two media relatively devoid of glucose and phosphate (e.g., P1), with one having the addition of essential amino acids and glutamate (Quinn's Advantage Medium).

RESULTS

For fresh cycles, the implantation rate was significantly higher for Quinn's. There was less fragmentation with P1 and Quinn's. For frozen cycles, the viable pregnancy, implantation rates and embryo quality were higher for Quinn's and P1 than HTF.

CONCLUSION

Removal of glucose and phosphate for day-2 embryos improves in vitro fertilization outcome after embryo transfer. It is not clear if adding certain non-essential amino acids and glutamate provides further improvement.

Evidence using a shared oocyte pool that the sperm rather than the oocyte in some cases may be responsible for the production of embryos with a high percentage of fragmented blastomeres--case report

PURPOSE

Hypothesis--a sperm defect rather than an oocyte problem may occasionally be responsible for blastomere fragmentation.

METHODS

The morphology of embryos in pairs of women producing embryos from a common pool of oocytes but fertilized by two different sperm sources was performed to see if a pair could be detected where one woman produced embryos with very little blastomere fragmentation vs the other woman having embryos with extensive fragmentation.

RESULTS

An oocyte donor was identified who produced 49 oocytes resulting in 17 embryos for the infertile donor to evaluate and 13 for the recipient. Almost all of the donor embryos showed extensive fragmentation vs very little for the recipient embryos.

CONCLUSION

The sperm, in some cases at least, may be the etiologic factor for blastomere fragmentation.

Development of sustainability indicators by communities in China: a case study of Chongming County, Shanghai

Public participation as a means of identifying sustainability indicators for Chongming County, Shanghai, China was evaluated by an international group drawing on established best practice. An initial 'long list' of 86 sustainability indicators, based on previous indicator systems developed in China, was identified. This 'long list' was reduced via consultations with local academics and local-government officers from Shanghai City and Chongming County to a 'short list' of 17 indicators. This short-list was subjected to further community consultation involving 159 local-government officers, teachers, students (aged 12-14 years), farmers and workers. Data from the consultations indicated differences in the understanding of sustainable development among the different sectors. By combining the data from the different sectors it was possible to identify a consensus around 4 core and 7 additional indicators. These are proposed as indicators which could be used to steer local activities directed towards sustainable development. The list of indicators produced by the people of Chongming Island was compared to local indicator systems in Europe. In comparison with European lists the Chongming list was found to have a greater emphasis on economic development but a similar level of concern for environmental matters. This study has special significance as it reports on the implementation of a process involving local resident participation in the process of sustainable development in China.

Evidence that the adverse effect of controlled ovarian hyperstimulation on successful pregnancy outcome following embryo transfer may be related to premature trophoblast invasion

PURPOSE

To determine if premature trophoblast invasion may be a contributing factor to lower fecundity associated with controlled ovarian hyperstimulation (COH) and in vitro fertilization (IVF).

METHODS

Blood samples were obtained three-five days after ET to measure expression by lymphocytes of a 34 kDa protein known as the progesterone-induced blocking factor (PIBF) using an immunocytochemistry technique. Clinical and viable pregnancy rates were determined according to whether PIBF was detected or not.

RESULTS

Progesterone-induced blocking factor was positive in 14 of 67 (21%). Clinical pregnancy rates following fresh ET were 7.1% for those positive for PIBF versus 43.4% for those negative for PIBF.

CONCLUSIONS

Progesterone-induced blocking factor production requires allogeneic induction of progesterone receptors in gamma/delta T-cells. This suggests early detection of PIBF may be related to premature trophoblast invasion possibly into an endometrium not yet prepared for the trophoblast, thus possibly leading to early immune rejection of the fetus.

Association between protease-specific proteolytic cleavage of brevican and synaptic loss in the dentate gyrus of kainate-treated rats

Proteolytic fragments generated by ADAMTS (a disintegrin and metalloprotease with thrombospondin motifs)-mediated cleavage of the aggregating chondroitin sulfate proteoglycan, brevican, have been identified, but not localized in the CNS. The purpose of this study, using kainate-induced CNS lesion, was to examine the spatial and quantitative relationship between ADAMTS1 and 4 mRNA expression and ADAMTS-mediated cleavage of brevican (as determined by the abundance of the neo-epitope QEAVESE at the C-terminal of the cleaved brevican G1 domain). In untreated rats, in situ hybridization and reverse transcriptase polymerase chain reaction indicated that ADAMTS4 expression was higher than ADAMTS1 and was localized to hippocampus, temporal lobe and other areas of cortex, striatum and hypothalamus. ADAMTS4 mRNA expression in these regions correlated with the presence of the QEAVESE neo-epitope, which was concentrated in perineuronal nets and in neuropil. In rats that seized after kainate, there was a dramatic elevation in ADAMTS1 and ADAMTS4 transcript that correlated and co-localized with a robust elevation in an extractable, 55-kDa fragment of brevican in temporal lobe and hippocampus. This fragment consisted, at least in part, of the ADAMTS-cleaved epitope G1-QEAVESE. The kainate-induced elevation in this ADAMTS-cleaved fragment was localized to amygdaloid and thalamic nuclei, hippocampus, caudate-putamen, cingulate cortex, and the outer molecular layer of the dentate gyrus where it was accompanied by a robust elevation in ADAMTS1 and 4 mRNA and a 28% decline in synaptic density 5 days after kainate.Thus, complexes of extracellular matrix proteins that exist in perineuronal nets and in the neuropil are cleaved by specific matrix-degrading proteases at early time points during excitotoxic neurodegeneration. The observed ADAMTS-induced cleavage of brevican in the dentate outer molecular layer is closely associated with diminished synaptic density, and may, therefore, contribute to synaptic loss and/or reorganization in this region.

Effect of transferring frozen-thawed embryos resulting from fertilization of immature oocytes matured one day in culture prior to intracytoplasmic sperm injection (ICSI) on implantation rates

PURPOSE

To evaluate whether it is efficacious to allow immature (metaphase I or germinal vesicle stage) oocytes to incubate one more day and then perform ICSI.

METHOD

A retrospective study of frozen embryo transfers (ET) of deselected frozen embryos was performed to see if inclusion of a higher percentage of embryos derived from in vitro maturation of oocytes resulted in lower implantation rates.

RESULTS

The implantation rate following transfer of frozen-thawed embryos, where embryos derived from immature oocytes constituted < or = 40% of the embryos (group 1) was similar to group 2 with > 40% (11.3% vs 9.8%). However, group 1 had a 10.2% implantation rate for viable (past first trimester) sacs vs only 4.3% for group 2.

CONCLUSIONS

Pregnancies from transfer of frozen-thawed embryos derived from in vitro cultured immature oocytes are as likely to implant as the other deselected frozen-thawed embryos.

Indicators of fetal growth and infectious disease in childhood--a birth cohort with hospitalization as outcome

We evaluated the association between indicators of fetal growth and hospitalization with infectious disease during childhood in a cohort of 10,400 newborns. The cohort was based on children born to mothers who at about 36 weeks of gestation attended the midwife centres in Odense and Aalborg, Denmark for a routine examination. Women were recruited to the study from April 1984 to April 1987. After linkage with the National Hospital Registry, the first hospitalization with infectious disease from 6 months up to 12 years of age was identified. The cumulative incidence of hospitalization with infectious disease during follow-up was 18.9%. Preterm birth was associated with an increased risk of being hospitalized with infections during childhood (incidence rate ratio: 1.67, 95% CI: 1.33-2.10); low birth weight had a similar association, but only in preterm birth. Reduced birth length related to the head was correlated with an increased risk of hospitalization with infections. The effect of gestational age was mainly seen in the period close to the time of birth, but the children who were short at birth appeared to remain at increased risk throughout the age interval under analysis. In conclusion, the study suggests that preterm birth was the main factor underlying the association between low birth weight and the increased risk of hospitalization with infectious disease during childhood. However, it could not explain the increased risk in children who were short at birth.

Evolution of the Shanghai city region 1978-1998: an analysis of indicators

Building on a description of the present situation in Shanghai, a series of ten regionally relevant indicators are identified and described. Using data from 1978-1998, relationships between these economic, social and environmental indicators are explored using correlation and regression analysis. The analysis indicated that, in Shanghai, conflict between economy and environment existed throughout the research period and the evolution of the city region system seems to lack regularity. The key elements affecting trends in the development of the Shanghai city region are Gross Domestic Product, Total Investment and Urban Living Area per Head. The city region system seemed more sustainable, indicated by an improvement in environmental quality and relative lower investment growth rate, when the annual change rate of Gross Domestic Product was less than 7-8%.

Cumulative probability of pregnancy following IVF with ICSI and fresh or frozen embryo transfer

The authors studied the cumulative probability of pregnancy for up to 4 consecutive embryo transfer (ET) cycles with ICSI performed for male factor. Transfers could be either fresh or frozen. The clinical pregnancy rate (PR) for the first 4 cycles were similar [44% (61/366); 31% (44/138); 45% (14/31); 44% (4/9)]. Delivery rates were also similar. There was a lower PR on the second retrieval vs. the first retrieval (47% vs. 29%), but this may be related to most of the second retrievals occurring in the second transfer cycle (67%, 31/55); this may be explained by women who were poor responders and required another retrieval without a frozen ET. The majority of transfers in cycle 1 were fresh, whereas cycles 2-4 used primarily frozen-thawed embryos. These data should be helpful for patients requiring IVF with ICSI in deciding to continue with more IVF cycles or consider other

Model-based analysis of dynamics in vergence adaptation

We previously proposed a model to study the dynamics of disparity vergence responses. This model was based on known physiology and consisted of pulse and step neural control processes feeding a linear second-order oculomotor plant. Here, we apply a slightly modified version of that model to analyze the influence of short-term adaptation on vergence dynamics. This analysis showed that, unlike normal vergence responses, adapted responses could not be accurately simulated without a delay between the step and pulse components. Through simulations of normal vergence and adapted vergence responses, we found a strong correlation between delay of the step signal and the size of the movement overshoot. This correlation suggests a strong interaction between neural process generating the pulse and step motor control signals.

[Intact-bridge tympanomastoidectomy procedure: a reasonable option in the surgery of chronic otitis media and mastoiditis with cholesteatoma and/or granulation tissue]

OBJECTIVE

To study and evaluate a surgical option for the treatment of otitis media and mastoiditis with cholesteatoma and/or granulation tissue.

METHODS

The procedure is called intact-bridge tympanomastoidectomy (IBM). There are some modifications for the treatment of patients suffered from chronic otitis media and mastoiditis with cholesteatoma and/or granulation tissue. The features of IBM include: 1. the aditus, mastoid and attic opened and the intractable pathological tissues eradicated thoroughly. 2. the posterior tympanal space opened through the facial recess if necessary. 3. a widened middle ear space by lowering bony bridge established. 4. the adults blocked. 5. immediate or staging tympanoplasties conducted according to the conditions of mucosa in the tympanum.

RESULTS

The modified IBM procedure was performed on 62 ears from 61 cases. The follow-up has been 12-38 months and more than two years in 51 ears. The dry ear was obtained within 5-13 weeks with an average of 6 weeks. In 24.2% of ears the air-bone gap(ABG) was 20dB HL or less and within 21-30 dB HL in 41.9% of ears, the ABG over 31 dB HL was 16.1%.

CONCLUSION

Our results indicate that IBM procedure fulfills the desired purposes of both open- and close-cavity techniques, the thorough eradication of diseased tissue allow to get a dry ear and restoration of hearing. IBM, therefore, is a reasonable choice for the surgery of otitis media and mastoiditis with cholesteatoma and/or granulation tissue.

Assessment of equivalence on multiple endpoints

Some clinical trials aim to demonstrate therapeutic equivalence on multiple primary endpoints. For example, therapeutic equivalence studies of agents for the treatment of osteoarthritis use several primary endpoints including investigator's global assessment of disease activity, patient's global assessment of response to therapy, and pain. In this paper, thoughts on simultaneous equivalence assessment on three endpoints are presented. As pointed out by Berger and Hsu (1996), the conventional intersection-union test can be conservative. Simulation and computation are conducted to provide an insight on the conservativeness. We also provide a method to lower the confidence level and at the same time maintain the type I error when endpoints have normal distributions and are independent. If, in a particular analysis, the goal is to demonstrate equivalence on as many endpoints as possible, a step-up procedure can be used for selecting those endpoints for which equivalence may be demonstrated. This step-up procedure at the same time controls experimentwise error rate. The techniques are illustrated by a data example.

Pregnancy/implantation rates as related to age following transfer of frozen embryos produced by ICSI

A study has suggested that one drawback of ICSI is that if these embryos are cryopreserved they have lower implantation rates after thawing and transfer as compared to other frozen embryos derived from conventional oocyte insemination. Other studies have not shown such adverse effects on pregnancy rates following frozen embryo transfer (ET) of embryos formed by ICSI. The study presented here evaluated the largest number of frozen ET cycles of embryos following ICSI, which were compared to couples having frozen ET with embryos formed by conventional insemination. In women age 39 and younger, the clinical, viable, pregnancy rates and implantation rates were very similar. Similar rates were reached for the older group. These data convincingly demonstrate that fertilization by ICSI does not adversely effect the implanting capacity of frozen-thawed embryos.

Transforming growth factor-beta repression of matrix metalloproteinase-1 in dermal fibroblasts involves Smad3

Enhanced production of matrix metalloproteinase-1 (MMP-1, collagenase-1) is implicated in pathological tissue destruction. Transforming growth factor-beta (TGF-beta) prevents cytokine-induced MMP-1 gene expression in fibroblasts. In these studies, we examined the hypothesis that repression of MMP-1 may be mediated through the Smad signaling pathway. The results showed that Smad3 and Smad4, but not Smad1 or Smad2, mimicked the inhibitory effect of TGF-beta and abrogated interleukin-1beta (IL-1beta)-induced stimulation of MMP-1 promoter activity and NFkappaB-specific gene transcription in dermal fibroblasts. Experiments with truncation mutants indicated that both MH1 and MH2 domains of Smad3 were necessary for inhibitory activity. Dominant negative mutants of Smad3 or Smad4 and antagonistic Smad7, which disrupts ligand-induced Smad3 phosphorylation, abrogated the repression of MMP-1 transcription by TGF-beta. Similar results were obtained using immunoblot and Northern analysis. Furthermore, TGF-beta failed to repress MMP-1 promoter activity in Smad3-deficient murine embryonic fibroblasts. These results implicated cellular Smads in mediating the inhibitory effects of TGF-beta. Overexpression of the transcriptional co-activator p300, but not its histone acetyltransferase (HAT)-deficient mutant, was able to relieve repression of MMP-1 gene expression, suggesting that Smad-dependent inhibition may be due to increased competition between Smad proteins and IL-1beta signaling pathways for limiting amounts of cellular p300. Together, these results demonstrate that MMP-1 is a target for negative regulation by TGF-beta through cellular Smad3 and Smad4. Smad-mediated repression of MMP-1 gene expression may be important for preventing excessive matrix degradation induced by inflammatory cytokines; disruption of Smad signaling, as occurs in certain cancer cells, may thus be causally linked to uncontrolled tissue destruction mediated through MMP-1.

Intravascular local gene transfer mediated by protein-coated metallic stent

OBJECTIVE

To assess the feasibility, efficiency and selectivity of adenovirus-mediated gene transfer to local arterial wall by protein-coated metallic stent.

METHODS

A replication-defective recombinant adenovirus carrying the Lac Z reporter gene for nuclear-specific beta-galactosidase (Ad-beta gal) was used in this study. The coating for metallic stent was made by immersing it in a gelatin solution containing crosslinker. The coated stents were mounted on a 4.0 or 3.0 mm percutaneous transluminal coronary angioplasty (PTCA) balloon and submersed into a high-titer Ad-beta gal viral stock (2 x 10(10) pfu/ml) for 3 min, and then implanted into the carotid arteries in 4 mini-swines and into the left anterior descending branch of the coronary artery in 2 mini-swines via 8F large lumen guiding catheters. The animals were sacrificed 7 (n = 4), 14 (n = 1) and 21 (n = 1) days after implantation, respectively. The beta-galactosidase expression was assessed by X-gal staining.

RESULTS

The results showed that the expression of transgene was detected in all animal. In 1 of carotid artery with an intact intima, the beta-gal expression was limited to endothelial cells. In vessels with denuded endothelium, gene expression was found in the sub-intima, media and adventitia. The transfection efficiency of medial smooth muscle cells was 38.6%. In 2 animals sacrificed 7 days after transfection, a microscopic examination of X-gal-stained samples did not show evidence of transfection in remote organs and arterial segments adjacent to the treated arterial site.

CONCLUSIONS

Adenovirus-mediated arterial gene transfer to endothelial, smooth muscle cells and adventitia by protein-coated metallic stent is feasible. The transfection efficiency is higher. The coated stent may act as a good carrier of adenovirus-mediated gene transfer and have a potential to prevent restenosis following PTCA.

Class I and III polyhydroxyalkanoate synthases from Ralstonia eutropha and Allochromatium vinosum: characterization and substrate specificity studies

Class I and III polyhydroxyalkanoate (PHA) synthases catalyze the conversion of beta-hydroxybutyryl coenzyme A (HBCoA) to polyhydroxybutyrate. The Class I PHA synthase from Ralstonia eutropha has been purified by numerous labs with reported specific activities that vary between 1 and 160 U/mg. An N-terminal (His)6-PHA synthase was constructed and purified with specific activity of 40 U/mg. The variable activity is shown to be related to the protein's propensity to aggregate and not to incomplete post-translational modification by coenzyme A and a phosphopantetheinyl transferase. The substrate specificities of this enzyme and the Class III PHA synthase from Allochromatium vinosum have been determined with nine analogs of varied chain length and branching, OH group position within the chain, and thioesters. The results suggest that in vitro, both PHA synthases are very specific and provide further support for their active site structural similarities. In vitro results differ from studies in vivo.

Effects of ouabain and digoxin on gene expression of sodium pump alpha-subunit isoforms in rat myocardium

OBJECTIVE

To compare the effects of ouabain and digoxin on the gene expression of sodium pump alpha-subunit isoforms in the myocardium of rats.

METHODS

Normal Sprague-Dawley (SD) rats were injected with ouabain (20 micrograms.kg-1.d-1, i.p.), digoxin (32 micrograms.kg-1.d-1, i.p.) and normal saline (NS) once a day, respectively, and indirect systolic blood pressure was recorded once a week. Six weeks later, all of the rats were killed, and sodium pump alpha 1-, alpha 2-, and alpha 3-subunit mRNA levels in the myocardium were detected with the reverse transcription polymerase chain reaction (RT-PCR) method.

RESULTS

The systolic blood pressure of the rats infused with ouabain increased significantly at the end of week 6 (132.6 +/- 9.0 mm Hg vs 115.7 +/- 8.2 mm Hg, P < 0.01), while no difference in blood pressure was found between the digoxin group and the NS group. The expression of sodium pump alpha-subunit isoforms in the ventricular myocardium was regulated by either ouabain or digoxin. Both ouabain and digoxin stimulated expression of the alpha 3-isoform, whereas alpha 2 was unchanged in those two groups. alpha 1-isoform expression decreased in the ouabain group and was unchanged in the digoxin group.

CONCLUSIONS

These results suggest that both ouabain and digoxin could regulate sodium pump alpha-subunit isoform expression, which might be related to the physiological roles of endogenous ouabain and might be responsible for the difference in the pharmacological and toxicological effects of ouabain and digoxin, including their effects on blood pressure.

Neurophysiological evidence of spared upper motor conduction fibers in clinically complete spinal cord injury: discomplete SCI in rats

Motor evoked potentials (MEP) were recorded and characterized by epidural electrodes (scMEP) and extracellular microelectrodes (exMEP) on T(13) level from 10 normal rats and 40 rats with chronic spinal cord injury (SCI). The spinal cord of 40 anesthetized rats were injured with various severity (sham, 35, 70, and 100 g/cm impact injury) at T(8)-T(9) cord using Allen's drop model. The incline plane and Tarlov techniques were investigated to assess clinical neurological function. MEPs in the normal rats elicited by applying transcortical suprathreshold stimulation consisted of 3-4 early negative peaks (N(1), N(2), N(3), N(4)) followed by several late waves. The N(1) and N(2) peaks had their maximal amplitudes in the anterior and ventrolateral funiculus, respectively, irrespective of the polarity of stimulation, which indicated that these impulses were conducted mostly through the extrapyramidal pathways. The 100 g/cm impact injury or transection of the cord caused abolishment of the MEP signals distal to the lesion, whereas the 35 g/cm injury resulted in a latency shift and amplitude decrement of the MEP peaks. Out of 20 rats with 70 g/cm injuries, 18 showed clinically paraplegia. Among them, seven had neurophysiological evidence of residual conduction pathways through the injured cord segment, such as the presence of N(1) and N(2) peaks in scMEP or exMEP. After 4-aminopyridine (4-AP) administration (1 mg/kg), the amplitude of spared exMEP increased significantly and spread more widely. These results suggest that MEPs evoked by transcortical stimulation travel mostly in the extrapyramid tract. The present study provides further direct and objective electrophysiological evidences of spared functional axons after discomplete SCI, since many other studies on this field have achieved similar results previously. Furthermore, pharmaceutical treatment with 4-AP or other K(+) channel blocking agents proved to be a potential therapeutic strategy for patient with chronic SCI.

Arrhythmogenesis and contractile dysfunction in heart failure: Roles of sodium-calcium exchange, inward rectifier potassium current, and residual beta-adrenergic responsiveness

Ventricular arrhythmias and contractile dysfunction are the main causes of death in human heart failure (HF). In a rabbit HF model reproducing these same aspects of human HF, we demonstrate that a 2-fold functional upregulation of Na(+)-Ca(2+) exchange (NaCaX) unloads sarcoplasmic reticulum (SR) Ca(2+) stores, reducing Ca(2+) transients and contractile function. Whereas beta-adrenergic receptors (beta-ARs) are progressively downregulated in HF, residual beta-AR responsiveness at this critical HF stage allows SR Ca(2+) load to increase, causing spontaneous SR Ca(2+) release and transient inward current carried by NaCaX. A given Ca(2+) release produces greater arrhythmogenic inward current in HF (as a result of NaCaX upregulation), and approximately 50% less Ca(2+) release is required to trigger an action potential in HF. The inward rectifier potassium current (I(K1)) is reduced by 49% in HF, and this allows greater depolarization for a given NaCaX current. Partially blocking I(K1) in control cells with barium mimics the greater depolarization for a given current injection seen in HF. Thus, we present data to support a novel paradigm in which changes in NaCaX and I(K1), and residual beta-AR responsiveness, conspire to greatly increase the propensity for triggered arrhythmias in HF. In addition, NaCaX upregulation appears to be a critical link between contractile dysfunction and arrhythmogenesis.

Antagonistic regulation of type I collagen gene expression by interferon-gamma and transforming growth factor-beta. Integration at the level of p300/CBP transcriptional coactivators

Among the extracellular signals that modulate the synthesis of collagen, transforming growth factor-beta (TGF-beta) and interferon-gamma (IFN-gamma) are preeminent. These two cytokines exert antagonistic effects on fibroblasts, and play important roles in the physiologic regulation of extracellular matrix turnover. We have shown previously that in normal skin fibroblasts, TGF-beta positively regulates alpha2(I) procollagen gene (COL1A2) promoter activity through the cellular Smad signal transduction pathway. In contrast, IFN-gamma activates Stat1alpha, down-regulates COL1A2 transcription, and abrogates its stimulation induced by TGF-beta. The level of integration of the two pathways mediating antagonistic collagen regulation is unknown. We now report that IFN-gamma abrogates TGF-beta-stimulated COL1A2 transcription in fibroblasts by inhibiting Smad activities. IFN-gamma appears to induce competition between activated Stat1alpha and Smad3 for interaction with limiting amounts of cellular p300/CBP. Overexpression of p300 restored COL1A2 stimulation by TGF-beta in the presence of IFN-gamma, and potentiated IFN-gamma-dependent positive transcriptional responses. In contrast to fibroblasts, in U4A cells lacking Jak1 and consequently unable to activate Stat1alpha-mediated responses, IFN-gamma failed to repress TGF-beta-induced transcription. These results indicate that as essential coactivators for both Smad3 and Stat1alpha, nuclear p300/CBP integrate signals that positively or negatively regulate COL1A2 transcription. The findings implicate a novel mechanism to account for antagonistic interaction of Smad and Jak-Stat pathways in regulation of target genes. In fibroblasts responding to cytokines with opposing effects on collagen transcription, the relative levels of cellular coactivators, and their interaction with regulated transcription factors, may govern the net effect.

PEGylated PLGA nanoparticles as protein carriers: synthesis, preparation and biodistribution in rats

The aim of the present work was to assess the merits of PEGylated poly(lactic-co-glycolic acid) (PEG-PLGA) nanoparticles as protein and peptide drugs (PPD) carriers. PEG-PLGA copolymer, which could be used to prepare the stealth nanoparticles or long-circulating nanoparticles, was synthesized with methoxypolyethyleneglycol (MePEG) and PLGA. The structure of PEG-PLGA was confirmed with (1)H NMR and Fourier transform infrared (FTIR) spectrum, and molecular weight was determined by gel permeation chromatography (GPC). Bovine serum albumin (BSA), chosen as model protein, was encapsulated within the stealth nanoparticles with the double emulsion method. The particles were characterized in terms of size, zeta potential and in vitro release of the protein. The biological fate of the BSA-loaded nanoparticles following intravenous administration was determined over 24 h in rats. The experimental results showed that PEG-PLGA could be obtained by ring-opening polymerization of lactide and glycolide in the presence of MePEG. (1)H NMR and FTIR spectrum were consistent with the structure of PEG-PLGA copolymer. Molecular weight determined by GPC was 50800. The stealth nanoparticles loading BSA could be prepared by the double emulsion technique. The entrapment efficiency was 48.6%, particle size about 200 nm and zeta potential -16.1 mV. BSA release from the stealth nanoparticles showed an initial burst release and then sustained release. PEG-PLGA nanoparticles could extend half-life of BSA from 13.6 min of loaded in PLGA nanoparticles to 4.5 h and obviously change the protein biodistribution in rats compared with that of PLGA nanoparticles. Thus, PEG-PLGA nanoparticles could be an effective carrier for PPD delivery.

Involvement of chemokine receptors in breast cancer metastasis

Breast cancer is characterized by a distinct metastatic pattern involving the regional lymph nodes, bone marrow, lung and liver. Tumour cell migration and metastasis share many similarities with leukocyte trafficking, which is critically regulated by chemokines and their receptors. Here we report that the chemokine receptors CXCR4 and CCR7 are highly expressed in human breast cancer cells, malignant breast tumours and metastases. Their respective ligands CXCL12/SDF-1alpha and CCL21/6Ckine exhibit peak levels of expression in organs representing the first destinations of breast cancer metastasis. In breast cancer cells, signalling through CXCR4 or CCR7 mediates actin polymerization and pseudopodia formation, and subsequently induces chemotactic and invasive responses. In vivo, neutralizing the interactions of CXCL12/CXCR4 significantly impairs metastasis of breast cancer cells to regional lymph nodes and lung. Malignant melanoma, which has a similar metastatic pattern as breast cancer but also a high incidence of skin metastases, shows high expression levels of CCR10 in addition to CXCR4 and CCR7. Our findings indicate that chemokines and their receptors have a critical role in determining the metastatic destination of tumour cells.

In vitro translational analysis of genomic, defective, and satellite RNAs of Cryphonectria hypovirus 3-GH2

Cryphonectria hypovirus 3-GH2 (CHV3-GH2) is a member of the fungal virus family Hypoviridae that differs from previously characterized members in having a single large open reading frame with the potential to encode a protein of 326 kDa from its 9.8-kb genome. The N-terminal portion of the ORF contains sequence motifs that are somewhat similar to papain-like proteinases identified in other hypoviruses. Translation of the ORF is predicted to release autocatalytically a 32.5-kDa protein. A defective RNA, predicted to encode a 91.6-kDa protein representing most of the N-terminal proteinase fused to the entire putative helicase domain, and two satellite RNAs, predicted to encode very small proteins, also are associated with CHV3-GH2 infected fungal cultures. We performed in vitro translation experiments to examine expression of these RNAs. Translation of three RT-PCR clones representing different lengths of the amino-terminal portion of the ORF of the genomic RNA resulted in autocatalytic release of the predicted 32.5-kDa protein. Site-directed mutagenesis was used to map the processing site between Gly(297) and Thr(298). In vitro translation of multiple independent cDNA clones of CHV3-GH2-defective RNA 2 resulted in protein products of approximately 92 kDa, predicted to be the full-length translation product, 32 kDa, predicted to represent the N-terminal proteinase, and 60 kDa, predicted to represent the C-terminal two-thirds of the full-length product. In vitro translation of cDNA clones representing satellite RNA 4 resulted in products of slightly less than 10 kDa, consistent with the predicted 9.4 kDa product.

Involvement of chemokine receptors in breast cancer metastasis

Breast cancer is characterized by a distinct metastatic pattern involving the regional lymph nodes, bone marrow, lung and liver. Tumour cell migration and metastasis share many similarities with leukocyte trafficking, which is critically regulated by chemokines and their receptors. Here we report that the chemokine receptors CXCR4 and CCR7 are highly expressed in human breast cancer cells, malignant breast tumours and metastases. Their respective ligands CXCL12/SDF-1alpha and CCL21/6Ckine exhibit peak levels of expression in organs representing the first destinations of breast cancer metastasis. In breast cancer cells, signalling through CXCR4 or CCR7 mediates actin polymerization and pseudopodia formation, and subsequently induces chemotactic and invasive responses. In vivo, neutralizing the interactions of CXCL12/CXCR4 significantly impairs metastasis of breast cancer cells to regional lymph nodes and lung. Malignant melanoma, which has a similar metastatic pattern as breast cancer but also a high incidence of skin metastases, shows high expression levels of CCR10 in addition to CXCR4 and CCR7. Our findings indicate that chemokines and their receptors have a critical role in determining the metastatic destination of tumour cells.

Type I error in sample size re-estimations based on observed treatment difference

Sample size re-estimation based on an observed difference can ensure an adequate power and potentially save a large amount of time and resources in clinical trials. One of the concerns for such an approach is that it may inflate the type I error. However, such a possible inflation has not been mathematically quantified. In this paper the mathematical mechanism of this inflation is explored for two-sample normal tests. A (conditional) type I error function based on normal data is derived. This function not only provides the quantification but also gives mathematical mechanisms of possible inflation in the type I error due to the sample size re-estimation. Theoretically, based on their decision rules (certain upper and lower bounds), people can calculate this function and exactly visualize the changes in type I error. Computer simulations are performed to ensure the results. If there are no bounds for the adjustment, the inflation is evident. If proper adjusting rules are used, the inflation can be well controlled. In some cases the type I error can even be reduced. The trade-off is to give up some 'unrealistic power'. We investigated several scenarios in which the mechanisms to change the type I error are different. Our simulations show that similar results may apply to other distributions.

The influence of repetitive eye movements on vergence performance

We measured the peak velocity of convergence eye movement responses in four normal subjects before and after a large number of either repetitive vergence or repetitive saccadic eye movements. A 20% decrease in the mean value of peak velocity was observed in vergence responses after 100 repetitive step vergence eye movements. However, 100 cycles of slow sinusoidal vergence tracking did not induce any notable change in vergence dynamics. Five hundred repetitive saccadic eye movements also caused an approximately 20% decrease in peak velocity. The reduction in peak velocity was related to the number of repetitions for both vergence and saccadic fatiguing stimuli. The frequency of occurrence of double-vergences was also used as an index to monitor the influence of repetitive eye movements on convergence performance. Results showed that repetitive step convergence movements could double, or even triple, the frequency of the occurrence of double-vergence responses, while slow sinusoidal vergence tracking or repetitive saccades had no influence on the frequency of response doubles.

Maternal prenatal lifestyle factors and infectious disease in early childhood: a follow-up study of hospitalization within a Danish birth cohort

OBJECTIVES

To examine whether maternal prenatal lifestyle factors were associated with the risk of hospitalization with infectious disease during early childhood and whether a possible association was modified by fetal growth reduction.

METHODS

The study was based on a birth cohort of 10 400 newborns whose mothers attended the midwife centers in Odense and Aalborg, Denmark, from April 1984 to April 1987 at approximately the 36th week of gestation. Information on hospitalization with infectious disease was extracted from the National Hospital Discharge Registry, and newborns were followed up to the end of 1996.

RESULTS

Among 6022 children who were hospitalized at least once, 31.4% (n = 1892) were hospitalized with infectious diseases. The cumulative incidence rate of hospitalization with infections in children from the age of 6 months to 12 years was 18.9%. The incidence rate ratio in children born to mothers smoking during pregnancy was 1.24 (95% confidence interval: 1.13-1.36) compared with those of nonsmoking mothers. Mothers whose body mass index was <18 kg/m(2) were more likely to give birth to infants who were hospitalized with infectious disease (incidence rate ratio: 1.29; 95% confidence interval: 1.05-1.59). The increased risk was present in children only up to the age of 5 years.

CONCLUSIONS

The study shows that maternal smoking during pregnancy and a low prepregnancy body mass index are associated with a higher risk of hospitalization with infectious disease during early childhood. These associations are independent of fetal growth indicators.

Recording of spared motor evoked potentials and its augmentation by 4-aminopyridine in chronic spinal cord-injured rats

OBJECTIVE

To research the direct electrophysiological evidence of discomplete spinal cord injury (SCI) and the effect of 4-aminopyridine on it.

METHODS

Motor evoked potentials (MEPs), both spinal cord recorded MEPs (scMEPs) and extracellularly recorded MEPs (exMEPs) were recorded and characterized on a T13 epidural electrode (scMEPs) and an extracellular microelectrode (exMEPs) for 10 normal rats and 40 rats with lesions of various severity (sham, 35 g.cm force (gcf), 70 gcf, 100 gcf impact injury) at the T8-T9 cord using the Allen's drop model. The incline plane and Tarlov techniques were used to assess clinical neurological function.

RESULTS

MEPs in the normal rats were elicited by applying transcortical suprathreshold stimulation consisting of 3-4 early negative peaks (N1, N2, N3 and N4) followed by several late waves. The N1 and N2 peaks were largest in the anterior and ventrolateral funiculus, respectively, which was indicative of extrapyramidal pathways. The 100 gcf impact injuries and the cord transection abolished the MEP distal to the lesion, whereas the 35 gcf injuries resulted in a latency shift and amplitude decrement of the MEP peaks. Eighteen of the 20 rats with 70 gcf-injuries showed clinical paraplegia. Among them, 7 rats had neurophysiological evidence of residual conduction pathways through the lesioned cord segment, such as the presence of N1 and N2 peaks in the scMEPs or exMEPs. After 4-aminopyridine (4-AP) administrations (1 mg/kg), the amplitude of the spared exMEP increased significantly and spread more widely.

CONCLUSIONS

MEPs evoked by transcortical stimulation travel mostly in the extrapyramidal tract. MEP monitoring could provide an excellent method of detecting the functional integrity of the motor tracts after SCI, and could even detect spared motor fibers after discomplete SCI. Furthermore, the use of 4-AP or other K+ channel blocking agents may be a potential treatment for patients with chronic moderate to severe SCI.

Dentinogenesis imperfecta 1 with or without progressive hearing loss is associated with distinct mutations in DSPP

Dentinogenesis imperfecta 1 (DGI1, MIM 125490) is an autosomal dominant dental disease characterized by abnormal dentin production and mineralization. The DGI1 locus was recently refined to a 2-Mb interval on 4q21 (ref. 1). Here we study three Chinese families carrying DGI1. We find that the affected individuals of two families also presented with progressive sensorineural high-frequency hearing loss (gene DFNA39). We identified three disease-specific mutations within the dentin sialophosphoprotein gene (DSPP) in these three families. We detected a G-->A transition at the donor-splicing site of intron 3 in one family without DFNA39, a mutation predicted to result in the skipping of exon 3. In two other families affected with both DGI1 and DFNA39, however, we identified two independent nucleotide transversions in exons 2 and 3 of DSPP, respectively, that cause missense mutations of two adjacent amino-acid residues in the predicted transmembrane region of the protein. Moreover, transcripts of DSPP previously reported to be expressed specifically in teeth are also detected in the inner ear of mice. We have thus demonstrated for the first time that distinct mutations in DSPP are responsible for the clinical manifestations of DGI1 with or without DFNA39.

[Differential regulation of sodium pump alpha-subunit isoform gene by ouabain and digoxin in myocardium of rats]

OBJECTIVE

To compare the effects of ouabain and digoxin on both the systolic blood pressure (SBP) and sodium pump alpha-subunit expression in myocardium of rats.

METHODS

Normal Sprague-Dawley (SD) rats were injected with ouabain, digoxin or normal saline (NS) everyday and indirect SBP was recorded once a week. Six weeks later, all the rats were killed and sodium pump alpha1-, alpha2-, and alpha3-subunit were detected in the left ventricular myocardium with RT-PCR method and immunohistochemical assay at mRNA and protein levels.

RESULTS

At the end of six weeks SBP of rats infused with ouabain increased significantly (132.6 +/- 9.0 vs 115.7 +/- 8.2 mm Hg, P < 0.01), while no difference of SBP was found between digoxin group and NS group. The effects of ouabain and digoxin on sodium pump alpha-subunit isoform expression in myocardium were also different: both ouabain and digoxin stimulated expression of alpha3-isoform whereas alpha2-isoform unchanged at both mRNA and protein levels. alpha1-isoform was decreased in ouabain group and alpha1-isoform unchanged in digoxin group at both mRNA and protein levels.

CONCLUSION

It is suggested that both ouabain and digoxin could regulate sodium pump alpha-subunit isoform expression, which might be related to the physiological roles of endogenous ouabain and might be responsible for the difference between the pharmacological and toxicological effects of ouabain and digoxin, including their effects on blood pressure.

Direct repair of defect in lumbar spondylolysis and mild isthmic spondylolisthesis by bone grafting, with or without facet joint fusion

Forty-six patients with lumbar spondylolysis and mild isthmic spondylolisthesis were managed with direct repair of the defect with or without facet joint fusion in the affected segment. There were 24 males and 22 females, ranging in age from 15 to 56 years (average, 38.2 years). These patients had experienced clinical symptoms due to spondylolysis for between 4 months and 20 years (average, 5.3 years). Of 46 patients, 28 had no spondylolisthesis, 11 had Meyerding grade I vertebral slippage and 7 had grade II. Direct repair of 98 defects was performed on these patients. Twenty-six patients, in whom the disc adjacent to the defect was determined as degenerative by magnetic resonance imaging (MRI), simultaneously underwent facet joint fusion; 17 in one segment and 9 in two segments. The average period of follow-up was 50 months (24-92 months). Ninety-four defects achieved bony healing. As a result, 28 patients were graded as having an excellent outcome, 15 good, and 3 fair. Bone grafting in the defects achieves union between the loose lamina and the anterior element of lumbar vertebrae, and reconstructs the anatomic structure and physiologic functions of the lumbar vertebrae. There was no significant difference in outcome between the spondylolytic/spondylolisthetic patients with non-degenerative disc, who were treated with direct repair of defect only, and those with degenerative disc, who additionally underwent a fusion procedure (P > 0.05). The present series demonstrates a satisfactory result and a high rate of bony healing of the pars defect by this operative procedure in patients with lumbar spondylolysis and mild isthmic spondylolisthesis. Preoperative assessment of the disc degeneration with MRI is of great assistance in making the protocol choice of whether to opt for fusion.

Mechanistic studies on class I polyhydroxybutyrate (PHB) synthase from Ralstonia eutropha: class I and III synthases share a similar catalytic mechanism

The Class I and III polyhydroxybutyrate (PHB) synthases from Ralstonia eutropha and Chromatium vinosum, respectively, catalyze the polymerization of beta-hydroxybutyryl-coenzyme A (HBCoA) to generate PHB. These synthases have different molecular weights, subunit composition, and kinetic properties. Recent studies with the C. vinosum synthase suggested that it is structurally homologous to bacterial lipases and allowed identification of active site residues important for catalysis [Jia, Y., Kappock, T. J., Frick, T., Sinskey, A. J., and Stubbe, J. (2000) Biochemistry 39, 3927-3936]. Sequence alignments between the Class I and III synthases revealed similar residues in the R. eutropha synthase. Site-directed mutants of these residues were prepared and examined using HBCoA and a terminally saturated trimer of HBCoA (sT-CoA) as probes. These studies reveal that the R. eutropha synthase possesses an essential catalytic dyad (C319-H508) in which the C319 is involved in covalent catalysis. A conserved Asp, D480, was shown not to be required for acylation of C319 by sT-CoA and is proposed to function as a general base catalyst to activate the hydroxyl of HBCoA for ester formation. Studies of the [(3)H]sT-CoA with wild-type and mutant synthases reveal that 0.5 equiv of radiolabel is covalently bound per monomer of synthase, suggesting that a dimeric form of the enzyme is involved in elongation. These studies, in conjunction with search algorithms for secondary structure, suggest that the Class I and III synthases are mechanistically similar and structurally homologous, despite their physical and kinetic differences.

Canine parvovirus capsid assembly and differences in mammalian and insect cells

We examined the assembly processes of the capsid proteins of canine parvovirus (CPV) in mammalian and insect cells. In CPV-infected cells empty capsids assembled within 15 min, and then continued to form over the following 1 h, while full (DNA-containing) capsids were detected only after 60 min, and those accumulated slowly over several hours. In cells expressing VP1 and VP2 or only VP2, empty capsid formation was also efficient, but was slightly slower than that in infected cells. Small amounts of trimer forms of VP2 were detected in cells expressing wild type capsid proteins, but were not seen for mutants containing changes that prevented capsid assembly. CPV capsids accumulated in the cell nucleus, but mutant VP1 and VP2 proteins that did not assemble became distributed throughout the nucleus and the cytoplasm, irrespective of whether they were expressed as VP1 and VP2, or as VP2 only. Urea or pH treatment of empty capsids released dimer, trimer, or pentamer capsid protein combinations, while treatment of full capsids consistently released trimer and, in some cases, pentamer forms. When wild type or assembly-defective VP2 genes were expressed from recombinant baculoviruses in insect cells, most of the protein was recovered as noncapsid aggregates, and only a small proportion assembled into capsids. Both the assembled capsids and the noncapsid aggregates were seen primarily in the cytoplasm of the insect cells. The VP2 expressed in insect cells that was recovered in aggregates had an isoelectric point of about pH 6.3, while that recovered from assembled capsids had a pI of about 5.2, similar to that seen for the VP2 of capsids recovered from mammalian cells.

The optimal analgesic dose of rofecoxib: Overview of six randomized controlled trials

BACKGROUND

Rofecoxib, which specifically inhibits cyclooxygenase-2, is indicated for relief of the signs and symptoms of osteoarthritis and for the management of acute pain in adults. The authors present an overview of six placebo-controlled trials designed to evaluate the single-dose analgesic efficacy of a range of doses of rofecoxib in the treatment of postoperative dental pain.

METHODS

The six studies included doses of rofecoxib ranging from 7.5 to 500 milligrams. Maximal analgesic doses of a nonsteroidal anti-inflammatory drug, or NSAID, either naproxen sodium (550 mg) or ibuprofen (400 mg), were used as active comparators in each study. Analgesic efficacy was assessed with the use of validated self-administered questionnaires. The primary endpoint in each study was the total pain relief over the eight-hour postdose period. Additional endpoints were used to characterize the onset of analgesia and peak analgesic effect.

RESULTS

The results of these studies demonstrated that the efficacy of rofecoxib was dose-related, with 50 mg being consistently more effective than placebo for all measures of analgesic efficacy. Moreover, 50 mg was the lowest dose that reproducibly demonstrated an analgesic effect comparable to the effect of maximum single analgesic doses of NSAIDs.

CONCLUSION

The results of these studies support the recommended dose of 50 mg of rofecoxib once daily for the management of pain.

CLINICAL IMPLICATIONS

Rofecoxib, at a dose of 50 mg, is effective in the management of postoperative dental pain.

Satellite and defective RNAs of Cryphonectria hypovirus 3-grand haven 2, a virus species in the family Hypoviridae with a single open reading frame

Cryphonectria parasitica hypovirus 3-Grand Haven 2 (CHV3-GH2) is the most recently characterized member of the Hypoviridae family of viruses associated with hypovirulence of the chestnut blight fungus. Isolates of CHV3-GH2 contain either three or four double-stranded (ds) RNAs that are visible on ethidium bromide-stained agarose or polyacrylamide gels. Only the largest dsRNA appears to be required for virus infectivity, and was characterized previously (C. D. Smart et al., 1999, Virology 265, 66-73). In this study, we report the cloning, sequencing, and analysis of the other three dsRNAs. Sizes of the accessory dsRNAs are 3.6 kb (dsRNA 2), 1.9 kb (dsRNA 3), and 0.9 kb (dsRNA 4), compared to 9.8 kb for the genomic dsRNA segment (dsRNA 1). All three accessory dsRNA species are polyadenylated on the 3'-end of one strand, as is genomic dsRNA. DsRNA 2 represents a defective form of dsRNA 1, with the 5'-terminal 1.4 kb derived from the 5'-end of dsRNA 1 and the 3'-terminal 2.2 kb from the 3'-end of dsRNA 1. A single major open reading frame (ORF) is evident from deduced translations of dsRNA 2. The deduced translation product is a 91-kDa protein that represents a fusion consisting of the entire N-terminal protease and the entire putative helicase domain. DsRNAs 3 and 4 represent satellite RNAs that share very little sequence with dsRNA 1 and 2. DsRNA 4 is 937 nucleotides, excluding the poly(A)(+). The first AUG of the polyadenylated strand of dsRNA 4 occurs eight residues in from the 5'-terminus and would initiate the largest ORF on dsRNA 4, with the coding capacity for a 9.4-kDa protein. Within the deduced ORF and approximately 100 nucleotides from the 5'-end of dsRNA 4 is a 22-base sequence that is identical to sequences found in the nontranslated leaders of dsRNAs 1 and 2. DsRNA 3 accumulation in infected cultures varied, but it was less abundant than dsRNA 4. DsRNA 3 was found to represent a head-to-tail dimer of dsRNA 4 linked by a poly(A)/(U) stretch of 40-70 residues.