Surgical treatment of displaced acetabular fractures - 72 cases followed for 10 (6-14) years

Seventy-two displaced acetabular fractures managed surgically were evaluated retrospectively. The follow-up period was 10 (6-14) yr. The commonest fractures were posterior wall (28) and both columns (10). The surgical approaches were Kocher-Langenbeck (47), ilioinguinal (19) and extended iliofemoral (6). No neural monitoring was used in operations and no preventive agents for heterotopic ossification or thromboembolism were used perioperatively. Reduction was rated congruent in 59 (81.9%) and noncongruent in 13 (18.1%). The early postoperative complications were 1 vascular injury, 1 iatrogenic sciatic nerve injury, 1 deep vein thrombosis and 2 wound infections. The late complications were heterotopic ossification in 20 patients, avascular necrosis of the femoral head in 4 and symptomatic arthritis in 10. Functional outcomes were rated as excellent in 31, good in 23, fair in 7 and poor in 11. Our results show that traditional management is effective enough for displaced acetabular fractures.

Ipsilateral hip and distal femoral fractures

We tried to find the trauma mechanism and treatment rationale of ipsilateral concomitant hip and distal femoral fractures involving the articular surface. Between 1988 and 1995, 15 cases of ipsilateral hip (confined to neck or trochanteric areas of the femur) and distal (confined to supra- and intercondylar area of the femur) femoral articular fractures were collected. The hip fractures consisted of 10 trochanteric fractures and five neck fractures, which were managed with reduction and fixation in 14 (Knowles' pin in eight, DHS in four and standard Gamma nail in two), and primary bipolar hemiarthroplastry in one. The distal femoral articular fractures were open in 11; these were managed with radical debridement, implantation of Septopal chains and immediate internal fixation, followed by prophylactic autogenous bone grafting 6 weeks later in the recent six cases (five Judet plates, four dynamic condylar screws and two condylar plates). The other four closed distal femoral fractures were managed with early reduction and internal fixation (two Judet plate, one dynamic condylar screw and one condylar plate). The union time was 20.3 (12-48) weeks for proximal fractures and 23.7 (12-36) weeks for distal fractures. Early infection developed in three cases. Nonunion of a femoral neck fracture developed in one case. The other complications were implant failure in one, coxa vara in one, refracture in one, delayed union in one and knee stiffness in one.

Adjuvant sequential chemotherapy with doxorubicin plus cyclophosphamide, methotrexate, and fluorouracil (ACMF) with concurrent radiotherapy in resectable advanced breast cancer

Doxorubicin (Adriamycin) is an anthracycline effective in breast cancer. Despite a worldwide acceptance of Adriamycin in the adjuvant chemotherapy to maximize the survival benefit in the higher risk patients with breast cancer with promising results, oncologists in general do not favorably consider anthracyclines in the adjuvant treatment setting because of concern about the acute and chronic drug-related toxicity. For high-risk patients with breast cancer with more than three positive axillary lymph nodes, this series adopted a modified sequential regimen of ACMF first with Adriamycin (A) as a single agent in 3-weekly administration for three courses, and then a combination of cyclophosphamide, methotrexate, fluorouracil (CMF) every 3 to 4 weeks for six courses given in an outpatient setting concurrent with radiation therapy as an adjuvant treatment. A total of 56 patients underwent modified radical mastectomy and 3 others breast conservation surgery for their invasive breast cancer. Forty-seven (84%) patients completed the intended adjuvant treatment and 1 patient died of infection from treatment-related neutropenia. As a whole, the 3-year overall survival and disease-free survival rates of 56 patients analyzed were 82.3% and 64.4%, respectively. In this high-risk group, patients with four to nine positive nodes showed a slightly better trend of survival than those with 10 or more positive nodes without reaching statistically significant difference (36-month overall survival: 90.9% vs. 72.5%, p = 0.06; disease-free survival: 78.7% vs. 47.8%, p = 0.38). In this entire group of patients, locoregional recurrence was absent. A total of 55 episodes of grade III and IV hematologic toxicity were observed, with only one death from neutropenic sepsis. This modified ACMF regimen offers a good survival rate in breast cancer patients with more than three positive axillary lymph nodes. When these patients are carefully managed, the morbidity and mortality related to the treatment are low.

Clinical and epidemiological implications of swine hepatitis E virus infection

In nonendemic areas, most patients with acute hepatitis E were infected through traveling to endemic areas. However, some patients did not have a history of foreign travel before infection. Furthermore, high seroprevalence rates of antibody to hepatitis E virus (anti-HEV) were found in the general adult population in some countries without any recorded outbreak of hepatitis E. The significance of anti-HEV assay in these subjects remains obscure. To study if swine might be a source of HEV infection, HEV was tested in sera of 235 pigs in Taiwan, and from 5 patients with acute HEV infection who either denied or did not provide any foreign travel history. Three (1.3%) pigs had detectable swine HEV RNA. The swine and human HEV strains from Taiwan formed a monophyletic group, distinct from three previously reported groups: the United States human and swine HEV strains, the Mexico strain, and the largest group composed of the Asian and the African strains. The identity of nucleotide sequences was 84-95% between swine and human HEV strains in Taiwan, and 72-79% between Taiwan strains and those from different areas. The predicted amino acid sequence of a Taiwan swine HEV strain within the peptide 3-2 used in commercial anti-HEV assay showed a high identity (91-94%) with those of other human and swine HEV strains. Swine may be a reservoir of HEV and subclinical swine HEV infection may occur. Cross-reactivity of current anti-HEV assay may account for the high prevalence rate of anti-HEV in the general population in nonendemic areas.

The effect of posterior capsulorrhaphy in primary total hip arthroplasty: a prospective randomized study

Between 1994 and 1997, 180 cases of primary total hip arthroplasty (THA) were performed with the posterior (Moore) approach for a variety of indications and studies prospectively. The cases were separated randomly into 2 groups to evaluate the effect of posterior capsulorrhaphy in the prevention of postoperative dislocation. In group 1 (96 cases), closure of the arthroplasty was performed with a posterior capsulorrhaphy; in group 2 (84 cases), closure was performed without capsulorrhaphy. The follow-up period was 38 months (range, 12-60 months). No dislocations occurred in group 1, whereas 2 dislocations (2.3%) occurred in group 2. Although the factors affecting dislocation in primary THA are many, a posterior capsulorrhaphy may be helpful in the prevention of posterior dislocation of primary THA performed with a posterior approach.

Expression of Chx10 and Chx10-1 in the developing chicken retina

We have isolated full-length cDNAs of chick Chx10 and Chx10-1, two members of the paired type homeobox/CVC gene family. A comparison of sequences suggests that Chx10 is closely related to Alx/Vsx-2 and Vsx-2 of zebrafish and goldfish, respectively; while Chx10-1 is closely related to Vsx-1 of zebrafish and goldfish. Chx10 and Chx10-1 are expressed in the early retinal neuroepithelium, but not in the pigment epithelium and lens. The expression of Chx10 is present in most retinal neuroblasts, while Chx10-1 exhibits a novel pattern along the nasotemporal border. In the differentiating retina, both Chx10 and Chx10-1 are restricted to bipolar cells and are maintained at a low level in bipolar cells of the mature retina.

An early vision-based snake model for ultrasound image segmentation

Due to the speckles and the ill-defined edges of the object of interest, the classic image-segmentation techniques are usually ineffective in segmenting ultrasound (US) images. In this paper, we present a new algorithm for segmenting general US images that is composed of two major techniques; namely, the early-vision model and the discrete-snake model. By simulating human early vision, the early-vision model can capture both grey-scale and textural edges while the speckle noise is suppressed. By performing deformation only on the peaks of the distance map, the discrete-snake model promises better noise immunity and more accurate convergence. Moreover, the constraint for most conventional snake models that the initial contour needs to be located very close to the actual boundary has been relaxed substantially. The performance of the proposed snake model has been shown to be comparable to manual delineation and superior to that of the gradient vector flow (GVF) snake model.

Acridone alkaloids from the root bark of Severinia buxifolia in Hainan

Eight new acridone alkaloids, buxifoliadines-A--H together with nine known acridone compounds, were isolated and characterized from the root bark of Severinia buxifolia which was collected in Hainan province, China. Their structures were determined by spectroscopic methods. The relationship between acridone alkaloids with collecting area is discussed. The 13C-NMR spectra of the prenyl substituents at C-2 and/or C-4 of N-unsubstituted acridone alkaloids are also discussed.

Metal contents of fish from cultureponds near scrap metal reclamation facilities

Milkfish (Chanos chanos) from four fish-culture ponds adjacent to different metal recovery facilities along the Er-Jen River area, Tainan, Taiwan, were sampled to determine their metal contents. Chemical analysis showed that fish tissue contained different concentrations of Cu: 0.71-6.37 micrograms/g, Pb: ND (not detectable) approximately 41.04 micrograms/g, Cd: ND approximately 0.41 microgram/g, Al: 6.75-64.11 micrograms/g, Ni: 0.062-0.504 microgram/g and Zn: 16.11-41.86 micrograms/g. The average concentrations of Cu, Al, Zn, Cd and Pb in fish samples from some of the ponds were significantly higher than those from the reference pond. In addition, there were variations in metal concentrations of fish collected from different ponds. Pond D had the highest mean values of Cu, Cd and Zn, and Pond B of Al and Pb. Further investigations are needed to determine the source of metal contamination in the fish.

Protective effects of partially purified antigens of Actinobacillus pleuropneumoniae on experimentally infected mice

Three different models of protection experiments in mice using partially purified Actinobacillus pleuropneumoniae antigens such as crude culture supernatant extract (CCSE) and partially purified cell extract (PPCE) were attempted. Biochemical analysis showed that these two immunogens had protein concentration of 0.17-0.2 mg/mL and pentose concentration of 0.012-0.014 mg/mL. In the first model intranasal (IN) vaccination with different doses (from 0.01-10 IN-LD50) against IN challenge with the dose of 20 IN-LD50 containing 1.2 x 10(9) colony forming unit (CFU)/50 microL showed that only those with the dose more than 1 IN-LD50 had slight protection in terms of survival index (SI). In the second model of protection experiment, in which subcutaneous vaccination (s.c.) with the immunogens plus soybean oil against IN challenge with 10 IN-LD50 containing 6 x 10(8) CFU/50 microL, showed that formalin-killed bacteria (bacterin) and CCSE plus PPCE had only a slight protection whereas vaccination with CCSE or PPCE immunogen alone had no protection. In the third model of protection experiment, in which the intramuscular (i.m.) vaccination with the immunogens plus aluminum hydroxide [Al(OH3)] gel against intraperitoneal (i.p.) challenge with the dose of either 2 or 6 i.p.-LD50 containing 1.2-3.6 x 10(8) CFU/0.5 mL of 0.3% mucin saline showed highly effective.

Detection of methyl ethyl ketone in urine using headspace solid phase microextraction and gas chromatography

Headspace solid-phase microextraction coupled with gas chromatography/flame ionization detection was developed to measure urinary methyl ethyl ketone (MEK). A fused silica fiber coated with 75 microns carboxen/polydimethylsiloxane was used to extract urinary MEK. The optimal extraction conditions were obtained when temperature was 50 degrees C, extraction time was 15 minutes, and ammonium sulfate concentration was 0.5 g/mL. The optimal desorption temperature and time were 200 degrees C and 5 minutes, respectively. The concentration range of calibration curves was 27 to 8000 ng/mL of MEK. The within-day and between-day pooled coefficients of variation (9 concentrations, triplicate samples) were 5.4% and 8.8%, respectively. The limit of detection and limit of quantitation were 4.2 ng/mL and 21.6 ng/mL, respectively. The recovery (+/- standard deviation) of MEK was 100.2% +/- 8.6% (n = 3). MEK in urine was stable for at least 1 month when stored at -20 degrees C. This method proved to be applicable for the analysis of urinary MEK of exposed workers in a plastic material printing plant. We concluded that this new method is sensitive, inexpensive, simple, and reliable for measuring the occupational exposure of MEK.

Wingless transduction by the Frizzled and Frizzled2 proteins of Drosophila

Wingless (Wg) protein is a founding member of the Wnt family of secreted proteins which have profound organizing roles in animal development. Two members of the Frizzled (Fz) family of seven-pass transmembrane proteins, Drosophila Fz and Fz2, can bind Wg and are candidate Wg receptors. However, null mutations of the fz gene have little effect on Wg signal transduction and the lack of mutations in the fz2 gene has thus far prevented a rigorous examination of its role in vivo. Here we describe the isolation of an amber mutation of fz2 which truncates the coding sequence just after the amino-terminal extracellular domain and behaves genetically as a loss-of-function allele. Using this mutation, we show that Wg signal transduction is abolished in virtually all cells lacking both Fz and Fz2 activity in embryos as well as in the wing imaginal disc. We also show that Fz and Fz2 are functionally redundant: the presence of either protein is sufficient to confer Wg transducing activity on most or all cells throughout development. These results extend prior evidence of a ligand-receptor relationship between Wnt and Frizzled proteins and suggest that Fz and Fz2 are the primary receptors for Wg in Drosophila.

Gender determination in single bovine blastomeres by polymerase chain reaction amplification of sex-specific polymorphic fragments in the amelogenin gene

A sensitive technique for the sexing of bovine embryos was developed using polymerase chain reaction (PCR) amplification of the bovine amelogenin (bAML) gene on the X- and Y-chromosomes of Holstein dairy cattle. Cloning and DNA sequencing showed a 45.1% homology between the fifth intron of the bAML-X and bAML-Y gene with multiple deletions. A pair of sex-specific primers was designed to allow amplification of a single fragment of 467-bp from the X-chromosome of female cattle and two fragments of 467-bp and 341-bp from the X- and Y-chromosomes of male cattle. The primers were successfully applied to bovine sexing from single blastomeres isolated from day-6 to day-7 cow embryos by direct cell lysis and PCR. Our protocol of embryo sexing should be applicable to the diagnosis of defective genes in vitro in human embryos and in other domestic or recreational animals.

Production and design of more effective avian replication-incompetent retroviral vectors

Retroviral vectors have been invaluable tools for studies of development in vertebrates. Their use has been somewhat constrained, however, by the low viral titers typically obtained with replication-incompetent vectors, particularly of the avian type. We have addressed this problem in several ways. We optimized the transient production of avian replication-incompetent viruses in a series of cell lines. One of the optimal cell lines was the mammalian line 293T, which was surprising in light of previous reports that avian viral replication was not supported by mammalian cells. We also greatly increased the efficiency of viral infection. Pseudotyping with the vesicular stomatitus virus G (VSV-G) protein led to an over 350-fold increase in the efficiency of infection in ovo relative to infection with virus particles bearing an avian retroviral envelope protein. To further increase the utility of the system, we developed new Rous sarcoma virus (RSV)-based replication-incompetent vectors, designed to express a histochemical marker gene, human placental alkaline phosphatase, as well as an additional gene. These modified retroviral vectors and the VSV-G pseudotyping technique constitute significant improvements that allow for expanded use of avian replication-incompetent viral vectors in ovo.

Analysis of prognostic factors in Chinese women with breast cancer in southern Taiwan

BACKGROUND

We conducted a retrospective review of all early-stage breast cancer patients treated at the Veterans General Hospital-Kaohsiung to determine overall and disease-free survival rates, and to evaluate prognostic factors for these outcomes.

METHODS

During the period of October, 1990, to December, 1997, 332 patients with early-stage breast cancer were treated at our institution. Cox's multivariate regression analysis was used to select prognostic factors significant for overall survival and disease-free survival.

RESULTS

The survival rate for breast cancer patients was 88.35% at five years. Prognostic factors predicting breast cancer mortality included poorly differentiated histologic grade, four or more lymph nodes positive for metastasis and negative progesterone-receptor status. For disease recurrence, prognostic factors included positive nodes, aneuploidy and poorly differentiated histologic grading.

CONCLUSIONS

We conclude that a combination of lymph node status, DNA ploidy, histologic grading and progesterone-receptor status help to evaluate the possible outcomes for patients with breast cancer and to plan for optimal therapy.

Usefulness of molecular testing in Huntington's disease

BACKGROUND

Uncertainty in diagnosing Huntington's disease (HD) may occur in the absence of a family history or typical movement disorders. HD is characterized by a progressive disturbance of typical movement disorders (i.e., chorea, athetosis), psychiatric symptoms (i.e., depression, insomnia, anxiety, suspiciousness), and cognitive deterioration, in the absence of a dominant family history of similar disorders. Often, some of these symptoms are missing, which makes the diagnosis difficult. In recent years molecular testing has become the gold standard for diagnosing HD. Diagnostic accuracy for HD on genetic screening of patients and their families is important. We evaluated a polymerase chain reaction (PCR) technique for the detection of CAG trinucleotide repeats in the Huntington IT15 gene on chromosome 4 for the diagnosis of HD.

METHODS

A segment of the Huntington gene was amplified by PCR using the primers HD-1 and HD-3 flanking the CAG repeat sequence. Genomic PCR was performed on DNA extracted from the peripheral leukocytes of 12 patients from three unrelated families. One family had no documented history of movement or mental disorders, while the other two did. These two, therefore, required pre-symptomatic testing and exclusion of diagnosis in a seemingly symptomatic case.

RESULTS

We successfully identified four subjects with expansion of CAG trinucleotide repeats in Huntington gene IT15 on chromosome 4. Movement disorder was present in three of these subjects. One was the sister of subject 4, who was asymptomatic. A sister of subject 9 was ruled out from having HD by PCR despite having depression symptoms, which are frequently seen in HD patients.

CONCLUSIONS

Genetic testing is of prime importance in the establishment of an accurate diagnosis of Huntington's disease, especially in "sporadic" cases and presymptomatic family members, and for the exclusion of HD in family members with equivocal symptoms.

Analysis of saponins from black bean by electrospray ionization and fast atom bombardment tandem mass spectrometry

Saponins from black bean (Vigna mungo L. Hepper) were analyzed using positive and negative ion fast atom bombardment mass spectrometry (FAB-MS) and liquid chromatography/mass spectrometry. Methanol was used to extract the saponins from defatted black bean, which was partially purified by extraction with n-butanol, and the extract was dialyzed with 3000 M(r) cut-off tubing. The dialyzate was analyzed using mass spectrometry. According to FAB-MS/MS, mixtures from black bean contain soyasaponin I as the predominant saponin. In addition, MS/MS analysis was performed in which the structures of saponins of black bean cotyledon were determined to be soyasaponin I, soyasaponin II, soyasaponin V, 3-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-galactopyranosyl-(1 --> 2)-beta-D-glucuronopyranosyl]complogenin (saponin A) and 3-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 2)-beta-D-glucopyranosyl]oleanolic acid (saponin B). For the black bean shell and the root of black bean sprout, analysis confirmed the saponins of soyasaponin I, soyasaponin II, soyasaponin V, saponin A, saponin B, acetylsoyasaponin A(4) and soyasaponin beta(g). Moreover, all the studied saponins were found in the stem and leaves of the black bean sprouts, except soyasaponin beta(g) and acetylsoyasaponin A(4), respectively.

Treatment of large skeletal defects in the lower extremities using double-strut, free vascularized fibular bone grafting

This article reports on the use of double-strut, free vascularized fibular grafts to treat six patients with infected nonunion or traumatic bone loss in the femur or tibia after prolonged treatment and multiple operations. The defects were 6-13 cm long. Five patients achieved solid union within 6 months, and one patient required additional cancellous grafting to achieve union at the distal end of the fibula. One patient experienced a stress fracture due to strenuous exercise, and union was achieved 3 months after reapplying an external fixator. Although three patients had some restricted knee motion, all patients had a satisfactory outcome in regard to walking, and no limb-length discrepancies were noted in any patient.

DNA cleavage activities of Staphylococcus aureus gyrase and topoisomerase IV stimulated by quinolones and 2-pyridones

We have cloned Staphylococcus aureus DNA gyrase and topoisomerase IV and expressed them in Escherichia coli as polyhistidine-tagged proteins to facilitate purification and eliminate contamination by host enzymes. The enzyme preparations had specific activities similar to previously reported values. Potassium glutamate (K-Glu) stimulated the drug-induced DNA cleavage activity and was optimal between 100 and 200 mM for gyrase and peaked at 100 mM for topoisomerase IV. Higher concentrations of K-Glu inhibited the cleavage activities of both enzymes. Using a common buffer system containing 100 mM K-Glu, we tested the enzyme-mediated DNA cleavage activities of both gyrase and topoisomerase IV with oxolinic acid, norfloxacin, ciprofloxacin, trovafloxacin, clinafloxacin, and the 2-pyridone ABT-719. As expected, all drugs tested demonstrated greater potency against topoisomerase IV than against gyrase. In addition, cleavage activity was found to correlate well with antibacterial activity.

Salmonella infection in total hip replacement--report of successful reimplantation and review of the literature

A case of Salmonella enteritidis group C infection following total hip replacement was treated by resectional arthroplasty and appropriate antibiotics. Total hip replacement with reimplantation of an antibiotic-impregnated cemented hip prosthesis was performed five months later. The postoperative course was smooth and hip function was good, without any sign of infection recurrence throughout 10 years of follow-up. The treatment protocol and clinical results are discussed along with a review of the literature.

Induction of cell death by tumour necrosis factor (TNF) receptor 2, CD40 and CD30: a role for TNF-R1 activation by endogenous membrane-anchored TNF

Several members of the tumour necrosis factor receptor (TNF-R) superfamily can induce cell death. For TNF-R1, Fas/APO-1, DR3, DR6, TRAIL-R1 and TRAIL-R2, a conserved 'death domain' in the intracellular region couples these receptors to activation of caspases. However, it is not yet known how TNF receptor family members lacking a death domain, such as TNF-R2, CD40, LT-betaR, CD27 or CD30, execute their death-inducing capability. Here we demonstrate in different cellular systems that cytotoxic effects induced by TNF-R2, CD40 and CD30 are mediated by endogenous production of TNF and autotropic or paratropic activation of TNF-R1. In addition, stimulation of TNF-R2 and CD40 synergistically enhances TNF-R1-induced cytotoxicity. These findings describe a novel pro-apoptotic mechanism induced by some members of the TNF-R family.

Theory for the bending anisotropy of lipid membranes and tubule formation

We study the spontaneous symmetry breaking of the bending rigidity of lipid membranes in two principal directions by a Landau mean-field theory. When the temperature is below the tilting temperature (T(c)), the coupling between molecular orientation and membrane local curvature square leads to an increase of the bending rigidity in the tilting direction and therefore a spontaneous symmetry breaking in two principal directions. The asymmetry (Delta) of the bending rigidity undergoes a continuous change upon cooling and grows as T(c)-T for T<T(c). We discuss this anisotropical effect on the tilt structure of the ripple phase P(beta(')) of a nearly flat membrane and the sphere-to-tubule transition in a dilute solution of lipids. The transition between the spherical vesicle phase and the tubular phase is predicted to be first order.

Dominant effects of RET receptor misexpression and ligand-independent RET signaling on ureteric bud development

During kidney development, factors from the metanephric mesenchyme induce the growth and repeated branching of the ureteric bud, which gives rise to the collecting duct system and also induces nephrogenesis. One signaling pathway known to be required for this process includes the receptor tyrosine kinase RET and co-receptor GFR(α)-1, which are expressed in the ureteric bud, and the secreted ligand GDNF produced in the mesenchyme. To examine the role of RET signaling in ureteric bud morphogenesis, we produced transgenic mice in which the pattern of RET expression was altered, or in which a ligand-independent form of RET kinase was expressed. The Hoxb7 promoter was used to express RET throughout the ureteric bud branches, in contrast to its normal expression only at the bud tips. This caused a variable inhibition of ureteric bud growth and branching reminiscent of, but less severe than, the RET knockout phenotype. Manipulation of the level of GDNF, in vitro or in vivo, suggested that this defect was due to insufficient rather than excessive RET signaling. We propose that RET receptors expressed ectopically on ureteric bud trunk cells sequester GDNF, reducing its availability to the normal target cells at the bud tips. When crossed to RET knockout mice, the Hoxb7/RET transgene, which encoded the RET9 isoform, supported normal kidney development in some RET−/− animals, indicating that the other major isoform, RET51, is not required in this organ. Expression of a Hoxb7/RET-PTC2 transgene, encoding a ligand-independent form of RET kinase, caused the development of abnormal nodules, outside the kidney or at its periphery, containing branched epithelial tubules apparently formed by deregulated growth of the ureteric bud. This suggests that RET signaling is not only necessary but is sufficient to induce ureteric bud growth, and that the orderly, centripetal growth of the bud tips is controlled by the spatially and temporally regulated expression of GDNF and RET.

Hepatitis C virus core protein interacts with cellular putative RNA helicase

The nucleocapsid core protein of hepatitis C virus (HCV) has been shown to trans-act on several viral or cellular promoters. To get insight into the trans-action mechanism of HCV core protein, a yeast two-hybrid cloning system was used for identification of core protein-interacting cellular protein. One such cDNA clone encoding the DEAD box family of putative RNA helicase was obtained. This cellular putative RNA helicase, designated CAP-Rf, exhibits more than 95% amino acid sequence identity to other known RNA helicases including human DBX and DBY, mouse mDEAD3, and PL10, a family of proteins generally involved in translation, splicing, development, or cell growth. In vitro binding or in vivo coimmunoprecipitation studies demonstrated the direct interaction of the full-length/matured form and C-terminally truncated variants of HCV core protein with this targeted protein. Additionally, the protein's interaction domains were delineated at the N-terminal 40-amino-acid segment of the HCV core protein and the C-terminal tail of CAP-Rf, which encompassed its RNA-binding and ATP hydrolysis domains. Immunoblotting or indirect immunofluorescence analysis revealed that the endogenous CAP-Rf was mainly localized in the nucleus and to a lesser extent in the cytoplasm, and when fused with FLAG tag, it colocalized with the HCV core protein either in the cytoplasm or in the nucleus. Similar to other RNA helicases, this cellular RNA helicase has nucleoside triphosphatase-deoxynucleoside triphosphatase activity, but this activity is inhibited by various forms of homopolynucleotides and enhanced by the HCV core protein. Moreover, transient expression of HCV core protein in human hepatoma HuH-7 cells significantly potentiated the trans-activation effect of FLAG-tagged CAP-Rf or untagged CAP-Rf on the luciferase reporter plasmid activity. All together, our results indicate that CAP-Rf is involved in regulation of gene expression and that HCV core protein promotes the trans-activation ability of CAP-Rf, likely via the complex formation and the modulation of the ATPase-dATPase activity of CAP-Rf. These findings provide evidence that HCV may have evolved a distinct mechanism in alteration of host cellular gene expression regulation via the interaction of its nucleocapsid core protein and cellular putative RNA helicase known to participate in all aspects of cellular processes involving RNA metabolism. This feature of core protein may impart pleiotropic effects on host cells, which may partially account for its role in HCV pathogenesis.