Linear temporal and spatiotemporal stability analysis of two-layer falling films with density stratification

A detailed temporal and spatiotemporal stability analysis of two-layer falling films with density and viscosity stratification is performed by using the Chebyshev collocation method to solve the full system of linear stability equations. From the neutral curves Re(k) for the surface mode and the interface mode of instability, obtained for different density ratios gamma of the upper layer to the lower layer, it is found that smaller density ratios make the surface mode and the short-wave interface mode much more stable, and can even make the short-wave interfacial instability disappear. Moreover, through the study of the local growth rates of the spatiotemporal instability as a function of the ray velocity V , it is found that for not too small incline angles like theta=0.2, the two-layer flow is always convectively unstable, and there is a transition between long- and short-wave instabilities which is determined by the Briggs-Bers collision criterion. Due to the existence of the absolute Rayleigh-Taylor instability for gamma>0 and theta=0, a transition from convective to absolute instability can be detected at small incline angles, and the corresponding boundary curves are plotted for different Reynolds numbers, viscosity ratios, and incline angles. It is found that there exists a limit Reynolds number above which the two-layer film flow can only be convectively unstable for a fixed small incline angle. The spatial amplification properties of the convective waves are finally presented for both surface and interface modes.

Induction of specific cytolytic T lymphocytes using fusions of hepatocellular carcinoma (HCC) patient-derived dendritic cells and allogeneic HCC cell line

BACKGROUND/AIMS

To assess the ability of hepatocellular carcinoma (HCC) patient-derived dendritic cells (DCs) fused with allogeneic HCC cell line to activate autologous lymphocytes to generate specific cytotoxic T lymphocytes (CTL) in vitro.

METHODOLOGY

DCs were obtained by culturing adherent peripheral blood mononuclear cells (PBMC) from HCC patients in the presence of 100 microg/L recombinant human granulocyte/ macrophage- colony stimulating factor (rhGM-CSF) and 20 microg/L interleukin-4 (rhIL-4) for 1 week in vitro. DCs were fused with allogeneic HCC cell line HepG2 cells using polythyleneglycol (PEG), and the fusion cells were designated as DCs/HepG2. By labeling DCs and HepG2 with green and red fluoresceins, respectively, the cellular fusion was examined under fluorescence microscope. The ability of DCs/HepG2 to stimulate proliferation and differentiation of autologous lymphocytes was assessed by MTT method, and the specific killing efficacy of DCs/HepG2-induced CTL against HepG2 was evaluated.

RESULTS

HCC patient-derived DCs expressed a certain level of CD1a, HLA-DR, CD54, CD80 and CD86. Fluorescence microscopic examination demonstrated that co-incubation of DCs and HepG2 in the presence of PEG lead to generation of DCs/HepG2. In the mixed lymphocyte reaction assay, DCs/HepG2 had a significantly greater ability to activate proliferation of autologous lymphocytes, as compared with DCs alone, DCs plus HepG2, HepG2 alone and medium control (P<0.05). The DCs/HepG2-activated CTL showed a potent specific killing efficacy against HepG2 cells.

CONCLUSIONS

Fusions of HCC patient-derived DCs and allogeneic HCC cell line could efficiently stimulate autologous lymphocytes to generate tumor-specific CTL in vitro. It might represent a promising approach of immunotherapy for HCC.

Low central venous pressure reduces blood loss in hepatectomy

AIM: To investigate the effect of low central venous pressure (LCVP) on blood loss during hepatectomy for hepatocellular carcinoma (HCC).

METHODS: By the method of sealed envelope, 50 HCC patients were randomized into LCVP group (n = 25) and control group (n = 25). In LCVP group, CVP was maintained at 2-4 mmHg and systolic blood pressure (SBP) above 90 mmHg by manipulation of the patient’s posture and administration of drugs during hepatectomy, while in control group hepatectomy was performed routinely without lowering CVP. The patients’ preoperative conditions, volume of blood loss during hepatectomy, volume of blood transfusion, length of hospital stay, changes in hepatic and renal functions were compared between the two groups.

RESULTS: There were no significant differences in patients’ preoperative conditions, maximal tumor dimension, pattern of hepatectomy, duration of vascular occlusion, operation time, weight of resected liver tissues, incidence of post-operative complications, hepatic and renal functions between the two groups. LCVP group had a markedly lower volume of total intraoperative blood loss and blood loss during hepatectomy than the control group, being 903.9 ± 180.8 mL vs 2 329.4 ± 2 538.4 (W = 495.5, P < 0.01) and 672.4 ± 429.9 mL vs 1 662.6 ± 1 932.1 (W = 543.5, P < 0.01). There were no remarkable differences in the pre-resection and post-resection blood losses between the two groups. The length of hospital stay was significantly shortened in LCVP group as compared with the control group, being 16.3 ± 6.8 d vs 21.5 ± 8.6 d (W = 532.5, P<0.05).

CONCLUSION: LCVP is easily achievable in technique. Maintenance of CVP ≤ 4 mmHg can help reduce blood loss during hepatectomy, shorten the length of hospital stay, and has no detrimental effects on hepatic or renal function.

Percutaneous microwave and radiofrequency ablation for hepatocellular carcinoma: a retrospective comparative study

BACKGROUND

Percutaneous microwave ablation and radiofrequency ablation are two commonly used modalities for the treatment of hepatocellular carcinoma; however, comparisons of them have not been documented adequately.

METHODS

Of 102 patients with biopsy-proved hepatocellular carcinoma, 49 (98 nodules) were treated percutaneously with microwave ablation and 53 (72 nodules) with radiofrequency ablation. The local tumor control, complications related to treatment, and long-term results of the two modalities were compared retrospectively.

RESULTS

The complete ablation rates were 94.9% (93/98) using microwave ablation vs 93.1% (67/72) using radiofrequency ablation (P = 0.75), and no significant differences were found either in the ablation of tumors of 3.0 cm or less (P = 1.00) or in those of more than 3.0 cm (P = 1.00) between the two modalities. The local recurrence rates were 11.8% (11/93) using microwave ablation vs 20.9% (14/67) using radiofrequency ablation (P = 0.12), and there were no significant differences between the two modalities either in tumors of 3.0 cm or less (P = 0.36) or in those of more than 3.0 cm (P = 0.82). The rates of major complications associated with microwave ablation and radiofrequency ablation were 8.2% (4/49) vs 5.7% (3/53; P = 0.71). The disease-free survival rates in the microwave ablation group were 45.9%, 26.9%, 26.9%, and 13.4% at 1, 2, 3, and 4 years, respectively, and those in the radiofrequency ablation group were 37.2%, 20.7%, and 15.5% at 1, 2 and 3 years, respectively (P = 0.53). The 1-, 2-, 3-, and 4-year cumulative survival rates for patients who underwent microwave ablation were 81.6%, 61.2%, 50.5%, and 36.8%, respectively, and for patients who underwent radiofrequency ablation the rates were 71.7%, 47.2%, 37.6%, and 24.2%, respectively (P = 0.12).

CONCLUSIONS

Percutaneous microwave ablation and radiofrequency ablation are both effective methods in treating hepatocellular carcinomas. The local tumor control, complications related to treatment, and long-term survivals were equivalent for the two modalities.

Systemic chemo-immunotherapy for advanced-stage hepatocellular carcinoma

AIM: To evaluate the therapeutic efficacy of systemic chemo-immunotherapy for advanced hepatocellular carcinoma (HCC).

METHODS: Twenty-six patients with advanced HCC were treated by using systemic chemo-immunotherapy (PIAF regimen), which consisted of cisplatin (20 mg/m²) intravenously daily for 4 consecutive day, doxorubicin (40 mg/m²) intravenously on day 1, 5-fluorouracil (400 mg/m²) intravenously daily for 4 consecutive day, and human recombinant α-interferon-2a (5 Mu/m²) subcutaneous injection daily for 4 consecutive day. The treatment was repeated every 3 wk, with a maximum of six cycles.

RESULTS: A total of 90 cycles of PIAF treatment were administered, with a mean number of 3.9 cycles per patient. Eight patients received six cycles of treatment (group A), and the remaining 18 were subjected to two to five cycles (group B). There were 0 complete response, 4 partial responses, 9 static diseases and 13 progressive diseases, with a disease control rate of 50% (13/26). The 1-year survival rate was 24.3%, with a median survival time of 6.0 mo. Group A had a remarkably better survival as compared with group B, the 1- and 2-year survival rates were 62.5% vs 6.1% and 32.3% vs 0%, and a median survival time was 12.5 mo vs 5.0 mo (P = 0.001).

CONCLUSION: Systemic chemo-immunotherapy using PIAF regimen represented an effective treatment and could improve the survival rate and prolong the survival time in selected patients with advanced HCC.

Ultrasound-guided percutaneous boiling carboplatin injection (PBCI) for the treatment of small hepatocellular carcinoma: a preliminary study

BACKGROUND/AIMS

To evaluate the therapeutic efficacy of ultrasound-guided percutaneous injection of boiling carboplatin (PBCI) for small hepatocellular carcinoma (HCC).

METHODOLOGY

PBCI was used to treat 34 HCC patients with 57 tumor nodules less than 3cm in diameter. Thirty-two of them (94.1%) were recurrent cases, including postoperative recurrence in 28, recurrence after percutaneous microwave coagulation therapy in 2 and recurrence after transcatheter arterial chemoembolization in 2. The remaining 2 had an initially treated HCC. Two sessions of PBCI were administered within 1 week for each tumor nodule. Its influences on liver function and blood cell count were monitored. Local recurrence rate, incidence of distant recurrence and survival rate were calculated by Kaplan-Meier method and their influencing factors were analyzed.

RESULTS

Patients had a mean follow-up time of 12.7 +/- 5.4 months (from 3 to 22 months). Amount of boiling carboplatin solution (5mg/mL) injected per session ranged from 3mL to 35mL (10.9 +/- 6.9mL), and the total amount used in the two-session course ranged from 6mL to 65mL (21.8 +/- 13.4mL). Of 57 tumor nodules treated with two-session PBCI, technical success was achieved in 53 (93.0%). The cumulative local recurrence rate at 3, 6, 12, 18 months was 3.5%, 7.3%, 16.2% and 16.2%, respectively, with a mean local recurrence-free time of 19.4 +/- 0.8 months. Eighteen out of 34 patients (52.9%) developed distant recurrence, with a mean interval time to distant recurrence of 11.6 +/- 1.4 months. Incidence of distant recurrence at 6, 12, 18 months was 34.1%, 53.2% and 64.5%, respectively. The 1-year and 1.5-year survival rates were 78.3% and 64.2%, respectively, with a mean survival time of 17.8 +/- 1.1 months. Of 28 postoperative recurrent patients, PBCI markedly prolonged the mean postoperative tumor-free survival time from 21.1 +/- 3.4 months to 36.2 +/- 4.7 months (p<0.01). Univariate analysis demonstrated that patients with Child-Pugh grade A liver function had a significantly longer survival time and greater survival rate than those with grade B and C (p<0.05). There were no remarkable changes in liver function and complete blood cell count after PBCI and no major complications were observed.

CONCLUSIONS

PBCI represented as an effective and safe percutaneous injection therapy for small HCC. It needed only two sessions for the vast majority of HCC less than 3cm in diameter and thus had the advantage of being much less invasive.

Eliciting specific antitumor immunity against hepatocellular carcinoma in vitro by fusions of HCC patient-derived dendritic cells with HCC cells

AIM: To investigate the ability of fusions of HCC patient-derived dendritic cells (DC) with HCC cells to induce autologous T lymphocytes to elicit specific immunity against HCC in vitro.

METHODS: Dendritic cells isolated from HCC patient peripheral blood were cultured and proliferated in vitro for one wk by using recombinant human granulocyte/macrophage-colony stimulating factor (rhGM-CSF) and interleukin-4 (rhIL-4). Expression of DC surface markers was assessed by flow cytometry. Fusions of DC with HepG2 cells (HepG2/DC) were achieved by polythyleneglycol (PEG). The ability of HepG2/DC to stimulate proliferation and differentiation of autologous T lymphocytes was assessed by MTT method, and the specific killing efficacy of HepG2/DC-induced cytotoxic T lymphocytes (CTL) to HepG2 was evaluated.

RESULTS: Following one wk culture, DC presented a high-level expression of CD1a, HLA-DR, CD54, CD80 and CD86. Fusions had remarkably greater ability to stimulate proliferation of autologous T lymphocytes in comparison with HepG2, HepG2+DC, DC and PBS, with an A value of 0.816±0.019 vs 0.541±0.020, 0.632±0.018, 0.564±0.018, 0.345±0.013, respectively (P<0.05). The HepG2/DC-activated CTLs showed a potent specific killing efficacy to HepG2.

CONCLUSION: Fusions of HCC patient-derived DC with HCC cells can effectively stimulate autologous T lymphocytes to elicit specific antitumor immunity against HCC, and may represent as a promising approach of immunotherapy for HCC.

Nuclear matrix protein expressions in hepatocytes of normal and cirrhotic rat livers under normal and regenerating conditions

We explored the feasibility of studying nuclear matrix protein (NMP) expressions of the hepatocytes in normal and cirrhotic rat livers with liver regeneration after partial hepatectomy. Sixteen Wistar healthy rats were studied with experimental liver regeneration and/or liver cirrhosis. Two-dimensional (2-D) gel electrophoresis was used to generate these NMP compositions from these rat liver samples. Several antibodies against cytokeratin, vimentin, actin, B23, HNF4alpha, and heat shock protein 70 were used for identification by Western blot. Totally, 41 strongly stained protein spots were characterized on the 2-D gels. Thirty-four protein spots were detected in all of these rat livers, of which, cytokeratin, vimentin, actin, HNF4alpha, and heat shock protein 70 were identified. B23 was detected in the regenerated livers. Three protein spots (s33, s34, and s35) were detectable only in NMP preparation extracted from the regenerating rat livers after hepatectomy. Another three protein spots (s36, s37, and s38) were detectable only in NMP preparation extracted from thioacetamide-induced cirrhotic rat livers. Under these conditions including experimental liver regeneration and/or liver cirrhosis, Over thirty higher abundance NMPs of hepatocytes were consistently expressed and considered as common and basic NMPs. Some of the NMPs are specific for liver regeneration and may play a critical role in cell proliferation and cell cycle, and some are specific for liver cirrhosis.

Usefulness of three-dimensional sonography in procedures of ablation for liver cancers: initial experience

OBJECTIVE

To investigate the usefulness of three-dimensional sonography in procedures of ablation for liver cancers.

METHODS

Two- and three-dimensional sonography were used in guiding 18 chemical ablation procedures (7 with boiling carboplatin ablation and 11 with ethanol ablation) and 21 radio frequency ablation procedures for treatment of liver cancers. The applicator conspicuity depicted by the 2 imaging modalities, the confidence level of the operator in determining the position relationship between the applicator and the tumor using the 2 imaging modalities, and the alteration of ablation procedures were evaluated.

RESULTS

Three-dimensional sonography was better than two-dimensional sonography in delineation of multitined, expandable electrode tips in radio frequency ablation procedures, whereas the 2 modalities were equal in depicting percutaneous transhepatic cholangiography needle tips in chemical ablation procedures. Three-dimensional sonography significantly enhanced the confidence level in defining the spatial relationship between applicator and tumor in comparison with two-dimensional sonography (P < .01). Suboptimal applicator placement was detected in 6 (15%) of 39 ablation procedures on three-dimensional sonography: 3 chemical ablation procedures and 3 radio frequency ablation procedures. Applicator adjustment was required in 3 chemical ablation procedures. In 15 (38%) of 39 procedures, three-dimensional sonography allowed better visualization of the position relationship between the applicator and adjacent critical structures.

CONCLUSIONS

Three-dimensional sonography was useful in delineation of expandable radio frequency electrodes, improvement of operator confidence level, determination of applicator placement, and visualization of the position relationship between the applicator and adjacent critical structures during procedures of liver cancer ablation under image guidance.

Prognostic significances of tumor-infiltrating S-100 positive dendritic cells and lymphocytes in patients with hepatocellular carcinoma

BACKGROUND/AIMS

To investigate the prognostic significances of dendritic cells and lymphocytes infiltration in hepatocellular carcinoma.

METHODOLOGY

The clinicopathological and follow-up data of 44 patients with hepatocellular carcinoma, who underwent curative resection of tumor in our hospital from January 1995 to July 1996, were collected. Immunohistochemical staining was employed to detect the S-100 positive dendritic cells in the tumor tissue, and lymphocytes infiltration was evaluated simultaneously. The relationship of the tumor-infiltrating dendritic cells and lymphocytes to the postoperative recurrence-free time and survival rate was analyzed.

RESULTS

Either the tumor-infiltrating dendritic cells or the tumor-infiltrating lymphocytes alone had no significant relationship to the postoperative recurrence-free time and survival rate. By taking into consideration both tumor-infiltrating dendritic cells and lymphocytes simultaneously, the patients were classified into two groups. Group A included patients having dendritic cell counts > or = 20 cells/10 high power fields together with positive lymphocytes infiltration (n = 17), and group B consisted of patients having dendritic cell count > or = 20 cells/10 high power fields but with negative lymphocytes infiltration or dendritic cell count < 20 cells/10 high power fields with either positive or negative lymphocytes infiltration (n = 27). There were no significant differences in clinicopathological features between two groups. The recurrence-free time was markedly longer in group A as compared with group B, with a median time of 21.6 months for group A and 4.1 months for group B (P < 0.05). The 1-, 3-, 4-year survival rates were significantly greater in group A than those in group B, being 83.5% vs. 42.2%, 61.8% vs. 28.4% and 48.7% vs. 23.0%, respectively (P < 0.01).

CONCLUSIONS

Marked infiltration of dendritic cells together with lymphocytes in tumor tissue was closely related to the improved clinical prognosis in patients with hepatocellular carcinoma, and represented as an independent prognostic factor.

Estimation of liver tumor volume using a three-dimensional ultrasound volumetric system

The usefulness of a new three-dimensional ultrasound (3DUS) volumetric system developed recently was validated in volume measurement of liver tumor in the present study. The system was used to estimate the volumes of 22 regular phantoms, 25 irregular phantoms and 37 liver tumors from 33 patients. The results showed that the consumed time of measurement with the system ranged from 1 to 15 min, depending on different rotation angles. The measured volumes at different rotation angles all significantly correlated with the true volumes and there were no significant differences among measured volumes at different angles. The measurement error of 3DUS was 0.3% +/- 3.3% in regular phantoms, -0.4% +/- 3.7% in irregular phantoms and 0.9% +/- 11.3% in liver tumors, respectively, as compared with -5.3 +/- 9.4%, 13.6 +/- 28.0% and 15.3 +/- 37.3% for two-dimensional ultrasound, respectively (all p < 0.05). The volume estimation with 3DUS also had significant intraobserver and interobserver reproducibility both in vitro and in vivo. It can be concluded that the new system that we used can greatly reduce the consumed time and manual labor for volume measurement with high accuracy and reproducibility. 3DUS volumetry using the new system is more acceptable and valuable in clinical practice and is expected to be useful for evaluation of the efficacy of tumor therapy in situ in patients with hepatic tumors.

Comparison of three- and two-dimensional sonography in diagnosis of gallbladder diseases: preliminary experience

OBJECTIVE

To compare three-dimensional sonography with two-dimensional sonography for diagnosis of gallbladder diseases.

METHODS

Sixty-three patients with gallbladder diseases were examined with two- and three-dimensional sonography. The morphologic features presented on both modalities were analyzed, and the diagnostic accuracies of both modalities were evaluated and compared.

RESULTS

Both two- and three-dimensional sonography facilitated correct diagnosis in all patients with gallstones. Three-dimensional sonography had no influence on the diagnosis of gallstones compared with two-dimensional sonography. Three-dimensional sonography showed the granular surfaces in 18 (81.8%) of 22 cases of polypoid lesions and the pedunculated fundus in 19 (86.4%) of 22, whereas two-dimensional sonography displayed them in 10 (45.5%) and 3 (13.6%) of 22, respectively (P < .05 and .001). Three- and two-dimensional sonography made correct differential diagnoses between non-neoplastic and neoplastic polyps in 20 (90.9%) and 12 (54.5%) of 22, respectively (P < .05). In gallbladder carcinoma, both three- and two-dimensional sonography accurately showed all the associated gallstones and intrahepatic bile duct dilatation. Two-dimensional sonography could not correctly define the locations of the lesions in 2 (28.6%) and tumor extension in 1 (14.3%) of 7 cases with pathologically proved gallbladder cancer, whereas three-dimensional sonography improved the diagnosis in these cases.

CONCLUSIONS

Three-dimensional sonography adds no advantages for diagnosis of gallstones compared with two-dimensional sonography, but it is better than two-dimensional sonography for differential diagnosis of gallbladder polyps and may improve the localization and staging for gallbladder carcinoma; however, additional studies are needed for further determination.

Three-dimensional gray scale volume rendering of the liver: preliminary clinical experience

OBJECTIVE

To investigate the potential clinical usefulness of three-dimensional gray scale volume rendering in the liver.

METHODS

Sixty-two patients were enrolled in the study and categorized into 2 groups: group I with ascites and group II without. Two types of volume-rendering modes, i.e., surface and transparent, were used to obtain the three-dimensional images. The data were reviewed to identify the differences between two- and three-dimensional images of the liver in each subject.

RESULTS

In group I, three-dimensional sonography was superior to two-dimensional sonography in terms of surface features, edges, overall three-dimensional impression, image clarity, and structural relationships. However, it seemed that three-dimensional sonography in the surface mode was inferior to two-dimensional sonography in showing intrahepatic structures, because it had decreased resolution. In group II, three-dimensional sonography was superior to two-dimensional sonography with respect to the continuity of intrahepatic vessels, overall three-dimensional impression of the vessels, image clarity, and the relationship between lesions and neighboring vessels. However, the resolution of the lesions was decreased in 7 cases of hepatocellular carcinoma.

CONCLUSIONS

Our experience suggests that three-dimensional gray scale volume rendering of the liver provides more diagnostic information than two-dimensional sonography; however, further studies are needed to evaluate its clinical importance.

Significance of portal hemodynamic investigation in prediction of hepatic functional reserve in patients with hepatocellular carcinoma undergoing operative treatment

BACKGROUND/AIMS

To evaluate clinical significance of portal hemodynamic investigation in prediction of hepatic functional reserve in patients with hepatocellular carcinoma undergoing operative treatment.

METHODOLOGY

By using the color Doppler velocity profile technique, preoperative portal hemodynamic status was assessed in 29 patients with hepatocellular carcinoma treated surgically, including 15 segmentectomies, 6 hemihepatectomies and 8 transarterial chemoembolizations. Forty-six normal volunteers were taken as control. Comparison of preoperative portal hemodynamics between patients recovering from operation smoothly (tolerant subgroup) and those with major complications or death (intolerant subgroup) was done, and discriminant analysis was employed to identify the cut-off value for significant parameters that maximally separate the tolerant subgroup from the intolerant subgroup.

RESULTS

In the portal trunk, CSVmax (maximum cross-sectional mean velocity) was significantly lower in the hepatocellular carcinoma group compared with the normal group (P < 0.01); flow volume was not obviously different between the two groups; congestion index was markedly higher in the hepatocellular carcinoma group than that of the normal group (P < 0.05). In the splenic vein, CSVmax and congestion index was not obviously different between the hepatocellular carcinoma and the normal groups; flow volume was significantly higher in the hepatocellular carcinoma group than that of the normal group (P < 0.05). In the hepatocellular carcinomas, twenty-three patients recovered smoothly from the operation and the remaining 6 had severe complications or death. Tolerant subgroup had a significantly higher preoperative CSVmax and flow volume and lower congestion index of the portal trunk compared with the intolerant subgroup (all P < 0.01). Discriminant analysis revealed that portal trunk CSVmax > 13.50 cm/s and flow volume > 12.13 mL/min/kg could predict tolerance for surgery, with an accuracy of 82.7% and 89.7%, respectively.

CONCLUSIONS

The results suggest that preoperative portal hemodynamic status in hepatocellular carcinomas had a close correlation with hepatic functional reserve, and CSVmax and flow volume of portal trunk might become valuable predictive parameters.

Inverse regulation of cyclin B1 by c-Myc and p53 and induction of tetraploidy by cyclin B1 overexpression

We have shown previously that mitotic spindle inhibitors allow the c-Myconcoprotein to uncouple mitosis from DNA synthesis, resulting in the acquisition of tetraploidy. This can also occur in the absence of spindle inhibition if c-Myc deregulation is combined with inactivation of the p53 tumor suppressor. Under these conditions, cyclin B1 protein is induced but retains its normal cell cycle regulation. We now show that the cyclin B1 promoter is directly but oppositely regulated by c-Myc and p53. Enforced expression of cyclin B1 also induces tetraploidy, either after mitotic spindle inhibition or in the absence of such inhibition if cyclin B1 is coexpressed with c-Myc. Cyclin B1 represents a new class of c-Myc target genes that is also regulated by p53. It is also the first identified downstream effector of c-Myc able to produce the chromosomal instability that characterizes virtually all tumor cells.

Mmip-2/Rnf-17 enhances c-Myc function and regulates some target genes in common with glucocorticoid hormones

Members of the Mad family of basic-helix-loop-helix-leucine zipper proteins inhibit the transcriptional activity of the c-Myc oncoprotein. Mmip-2/Rnf-17 is a RING-finger protein that interacts with all four known Mad proteins, redistributes them to the cytoplasm, and thus enhances c-Myc function. We generated cell lines in which Mmip-2/Rnf-17 was rendered glucocorticoid (GC)-inducible. Stable expression of Mmip-/Rnf-17 resulted in the expected transport of the most abundant endogenous mad protein, Mxi1, to the cytoplasm. Compensatory increases in Mxi1 and Mad3 transcripts, similar to those previously described in Mad1 null hematopoietic cells, were also seen. Mmip-2/Rnf-17 also sensitized cells to several different pro-apoptotic stimuli and regulated a subset of c-Myc target genes. Unexpectedly, some of these genes were also found to be modulated solely by GCs. Thus, the inhibition of Mad proteins by Mmip-2/Rnf-17 modulates c-Myc function by enhancing its ability to regulate a subset of its potential target genes. Our results also identify a previously unrecognized overlap between genes regulated by c-Myc- and GCs and provide a potential molecular basis for their regulation of common cellular functions.

Intraoperative liver ultrasound: the Chinese experience

This article introduces the experience in intraoperative liver ultrasound in China. Intraoperative liver ultrasound was mainly used in patients treated for hepatocellular carcinoma (HCC) and hepatolithiasis, with purposes for further diagnosis and decision making and guidance of surgical procedures. With respect to detection of liver tumors, intraoperative ultrasound (IOUS) was significantly more sensitive, especially in small foci, as compared with preoperative ultrasound and computed tomography scanning, as well as intraoperative inspection and palpation. It was also more precise in localizing lesions than preoperative imaging investigations. Intraoperative echoangiography via hepatic arterial injection of carbon dioxide was shown not only to help assess position of catheter and vascularity of tumors but also to improve sensitivity in detecting small tumor foci in patients undergoing hepatic arterial chemoembolization. Intraoperative ultrasound was also used to guide hepatectomies. It ensured to obtain curative resection of the tumors and maximum preservation of functioning hepatic parenchyma simultaneously. For hepatolithiasis, IOUS offered accurate localization of stones, lithotomy (with its guidance), reduction of the rate of residual stones, and follow-up of the outcome of lithotomy.

Color Doppler velocity profile assessment of portal hemodynamics in cirrhotic patients with portal hypertension: correlation with esophageal variceal bleeding

PURPOSE

Using the color Doppler velocity profile (CDVP), we investigated portal hemodynamics and their relationship with esophageal variceal bleeding (EVB) in patients with cirrhosis and portal hypertension.

METHODS

The hemodynamics of the portal trunk, right anterior portal branch, and splenic vein were evaluated in 69 cirrhotic patients with portal hypertension and 46 healthy volunteers. The CDVP, a recently developed Doppler software, was used to measure blood flow velocity and flow volume; evaluate the spatial distribution of flow velocities in the cross-section of a vessel (velocity profile), as reflected by the profile parameter (n); and assess changes in flow volume over time (flow profile). The congestion index was calculated by dividing the cross-sectional area by the maximum cross-sectional velocity (CSVmax). The hemodynamic features were compared between patients without a history of EVB [EVB(-)] and those with a history of EVB [EVB(+)], and a logistic regression model was employed to identify factors associated with EVB.

RESULTS

Compared with the healthy group, the cirrhotic group had a significantly lower mean CSVmax in the portal trunk and right anterior portal branch (both p < 0.01), a significantly elevated mean flow volume in the splenic vein and portal trunk (both p < 0.01), a significantly elevated mean ratio of splenic vein flow volume to portal trunk flow volume (SV/PT) (p < 0.001), and a significantly greater mean congestion index in the portal trunk, right anterior portal branch, and splenic vein (all p < 0.01). In the cirrhotic group, there was a significantly higher incidence of a flat flow pattern in the right anterior portal branch and a phasic flow pattern in the splenic vein than in the healthy group (both p < 0.01). Among cirrhotic patients, the EVB(+) group had a significantly greater mean flow volume in the splenic vein (p < 0.01), greater mean SV/PT (p < 0.01), greater mean spleen size (p < 0.05), and lower mean portal trunk n value (p < 0.05) compared with the EVB(-) group. Logistic regression analysis revealed that the SV/PT and portal trunk n value were independent EVB-related factors.

CONCLUSIONS

The results suggest that portal hemodynamics in cirrhotic patients are characterized by passive congestion and increased blood flow. However, these 2 features had different preponderances in different parts of the portal venous system. Increased flow in the splenic vein may be the primary source of increased portal flow and may play a role in the development of EVB. The SV/PT and portal trunk n value may be valuable factors for predicting EVB.

Effects of hepatic blood inflow occlusion on liver regeneration following partial hepatectomy in an experimental model of cirrhosis

BACKGROUND

Hepatic blood inflow occlusion during hepatectomy may influence postoperative liver regeneration. The aim of this study was to investigate the influence of hepatic blood inflow occlusion on liver regeneration following partial hepatectomy in thioacetamide-induced cirrhotic rats.

METHODS

Forty-three cirrhotic Wistar-Furth rats were randomly assigned to three groups. Rats in group 1 underwent 64 per cent hepatectomy alone, those in group 2 were subjected to 15 min hepatic blood inflow occlusion followed by 64 per cent hepatectomy, and animals in group 3 were subjected to 30 min inflow occlusion followed by 64 per cent hepatectomy. Liver function, 5-bromo-2'-deoxyuridine (BrdU) labelling index and percentage of initial liver weight on days 1, 2 and 7 posthepatectomy were assessed.

RESULTS

Rats in groups 1 and 2 had a significantly higher serum albumin level and a markedly lower alanine aminotransferase level than animals in group 3 on day 1 posthepatectomy (P < 0.05). There was no significant difference in the serum level of total bilirubin of the three groups on days 1, 2 and 7. The BrdU labelling index was significantly higher in groups 1 and 2 than in group 3 animals on day 1 posthepatectomy (P < 0.01 and P < 0.05 respectively). Percentages of initial liver weight were similar in groups 1, 2 and 3 on days 1, 2 and 7 after hepatectomy.

CONCLUSION

Hepatic blood inflow occlusion for up to 30 min suppressed DNA synthesis and hepatocyte proliferation at an early posthepatectomy stage and consequently delayed recovery of liver function in cirrhotic rats. However, it did not affect restoration of liver mass or survival after 64 per cent hepatectomy.

Mmip-2, a novel RING finger protein that interacts with mad members of the Myc oncoprotein network

Mad proteins are basic-helix-loop-helix-leucine zipper (bHLH-ZIP)-containing members of the myc oncoprotein network. They interact with the bHLH-ZIP protein max, compete for the same DNA binding sites as myc-max heterodimers and down-regulate myc-responsive genes. Using the bHLH-ZIP domain of mad1 as a yeast two-hybrid 'bait', we identified Mmip-2, a novel RING finger protein that interacts with all mad members, but weakly or not at all with c-myc, max or unrelated bHLH or bZIP proteins. The mad1-Mmip-2 interaction is mediated by the ZIP domain in the former protein and by at least two regions in the latter which do not include the RING finger. Mmip-2 can disrupt max-mad DNA binding and can reverse the suppressive effects of mad proteins on c-myc-responsive target genes and on c-myc + ras-mediated focus formation in fibroblasts. Tagging with spectral variants of green fluorescent protein showed that Mmip-2 and mad proteins reside in separate cytoplasmic and nuclear compartments, respectively. When co-expressed, however, the proteins interact and translocate to the cellular compartment occupied by the more abundant protein. These observations suggest a novel way by which Mmip-2 can modulate the transcriptional activity of myc oncoproteins.

A study of the ameliorating effects of carnitine on hepatic steatosis induced by total parenteral nutrition in rats

AIM: To investigate the effects of carnitine on ameliorating hepatic steatosis induced by total parenteral nutrition (TPN) in animal model.

METHODS: Eighteen normal Wistar rats and 19 cirrhotic Wistar rats induced by carbon tetrachloride were randomly divided into three groups, i.e., free access to food and drink (group A), TPN (group B) and TPN + carnitine (group C) for one week, respectively. Hepatic function, histology and its fat content were determined on the 7^th day.

RESULTS: Hepatic triglyceride (TG) and cholesterol (CHO) contents were significantly higher in groups B and C than in group A, and significantly lower in group C than in group B in both normal and cirrhotic rats (all P < 0.05). Histopathological examinations revealed that hepatic steatosis was more severe in group B than in group C in both normal and cirrhotic rats.

CONCLUSION: Carnitine can ameliorate hepatic steatosis associated with TPN in both non-cirrhotic and cirrhotic rats.

Quantitative assessment of power Doppler mapping in the detection of renal allograft complications

PURPOSE

We evaluated the usefulness of power Doppler (PD) imaging with a quantitative parameter in the identification of renal transplant complications.

METHODS

One hundred eight transplanted kidneys were subjected to PD examinations. The blood flow area ratio (BFAR), defined as the percentage of the area of color pixels within a given cross-sectional area placed over a region of a transplanted kidney, was measured using built-in color histogram software and used as a quantitative parameter for evaluating the status of allograft blood perfusion. The mean BFARs in the normal, acute rejection (AR), acute tubular necrosis (ATN), chronic rejection (CR), and cytomegalovirus infection (CMV) groups were compared.

RESULTS

The BFAR in the normal group tended to decrease gradually with the time interval since transplantation, but the mean value, 0.68+/-0.08, was significantly higher than that in the complication groups: AR, 0.43+/-0.18; ATN, 0.43+/-0.14; CR, 0.15+/-0.14; and CMV, 0.36+/-0.10 (p < 0.01 for all). When a BFAR of 0.60 or greater was used as the diagnostic criterion for normal allografts, a sensitivity, specificity, and accuracy of more than 90% could be achieved in the diagnosis of complications. However, owing to overlapping BFARs among the complication groups, the BFAR alone had a limited ability to differentiate the types of complications.

CONCLUSIONS

Although PD imaging has some limitations in identifying the nature of renal allograft complications, the use of the quantitative parameter BFAR in the PD assessment of renal allografts may be useful in detecting complications. Further studies are needed to explore the BFAR's clinical value.

C-myc overexpression and p53 loss cooperate to promote genomic instability

p53 monitors genomic integrity at the G1 and G2/M cell cycle checkpoints. Cells lacking p53 may show gene amplification as well as the polyploidy or aneuploidy typical of many tumors. The pathways through which this develops, however, are not well defined. We demonstrate here that the combination of p53 inactivation and c-myc overexpression in diploid cells markedly accelerates the spontaneous development of tetraploidy. This is not seen with either N-myc or L-myc. Tetraploidy is accompanied by significantly higher levels of cyclin B and its associated cdc2 kinase activity. Mitotic spindle poisons accelerate the appearance of tetraploidy in cells either lacking functional p53 or overexpressing c-myc whereas the combination is additive. Restoration of p53 function in cells overexpressing c-myc causing rapid apoptosis, indicating that cells yet to become tetraploid have nonetheless suffered irreversible genomic and/or mitotic spindle damage. In the face of normal p53 function, such damage would either be repaired or trigger apoptotis. We propose that loss of p53 and overexpression of c-myc permits the emergence and survival of cells with increasingly severe damage and the eventual development of tetraploidy.

Abnormalities in the p53 gene in tumors and cell lines of human squamous-cell carcinomas of the head and neck

Abnormalities in the p53 gene were studied in a series of cell lines of human squamous-cell carcinoma of the head and neck (SCCHN) and in tumor tissues. Restriction-fragment-length polymorphism (RFLP), quantitative hybridization and immunochemical analysis of mutant p53 proteins were combined to detect and characterize 3 different phases in the p53 gene alteration: mutation (in 9/9 cases), 17p13 deletion (9/10 cases) and amplification of the non-deleted allele (9/31 cases). In SCCHN, deletion of the p53 gene was nearly always accompanied by mutation, only one cell line studied having mutation without deletion. Alterations in the p53 gene are common in SCCHN, and involve a series of genetic events which occur in sequence during tumor progression.

Ontogenic Expression of Somatostatin-Messenger RNA in the Intestinal Tract of Neonatal Rats

Ontogenic expression of somatostatin (SRIF) -messenger RNA (mRNA) in the gastrointestinal tract was examined in neonatal rats aged from 1 day preterm to 60 days postpartum in comparison with that in the hypothalamus. SRIF-mRNA in the hypothalamus was already expressed in prenatal rats and its developmental change was relatively small. In contrast, a unique pattern of SRIF-mRNA expression was seen in the different intestinal regions, gastric antrum, duodenum, jejunum and colon. In the duodenum, SRIF-mRNA level was low at birth, markedly increased during the postnatal 3 days and declined to the previous level by day 21. Jejunal SRIF-mRNA was found in neonates but progressively decreased in a similar way to duodenum. On the contrary, gastric SRIF-mRNA level, which was low during early development, rose rapidly to a peak on day 21 and gradually declined to an adult level. In the colon age-related change was not conspicuous, remaining at a low level. These results indicate that (1) expression of SRIF gene in the intestinal tract is regulated by local factor(s) as well as developmental stage, and (2) shift of SRIF-mRNA pattern occurs during weaning from the duodenum-dominant infantile pattern to the gastric-dominant adult pattern.