HIV Nef-mediated cellular phenotypes are differentially expressed as a function of intracellular Nef concentrations

Nef is a regulatory protein encoded by the genome of both human and simian immunodeficiency virus. Its expression in T cells leads to CD4 and major histocompatibility complex class I modulation and either enhancement or suppression of T cell activation. How this viral protein achieves multiple and at times opposing activities has been unclear. Through direct measurements of Nef and the Nef-GFP fusion protein, we find that these events are mediated by different Nef concentrations. Relative to the intracellular concentration that down-modulates surface CD4, an order of magnitude increase in Nef-GFP expression is required for a comparable modulation of major histocompatibility complex class I, and a further 3-fold increase is necessary to suppress T cell activation.

Selective transcription and modulation of resting T cell activity by preintegrated HIV DNA

The quiescent nature of most peripheral T cells poses an effective limitation to human immunodeficiency virus (HIV) replication and, in particular, to viral integration into the host chromatin. Two HIV proteins, Nef and Tat, increase T cell activity, but a requirement of integration for viral gene expression would preclude a role for these proteins in resting cells. Here, we report that HIV infection leads to selective transcription of the nef and tat genes before integration. This preintegration transcription in quiescent cells leads to increased T cell activation and viral replication.

The mannose-sensitive hemagglutinin of Vibrio cholerae promotes adherence to zooplankton

The bacterium Vibrio cholerae, the etiological agent of cholera, is often found attached to plankton, a property that is thought to contribute to its environmental persistence in aquatic habitats. The V. cholerae O1 El Tor biotype and V. cholerae O139 strains produce a surface pilus termed the mannose-sensitive hemagglutinin (MSHA), whereas V. cholerae O1 classical biotype strains do not. Although V. cholerae O1 classical does not elaborate MSHA, the gene is present and expressed at a level comparable to that of the other strains. Since V. cholerae O1 El Tor and V. cholerae O139 have displaced V. cholerae O1 classical as the major epidemic strains over the last fifteen years, we investigated the potential role of MSHA in mediating adherence to plankton. We found that mutation of mshA in V. cholerae O1 El Tor significantly diminished, but did not eliminate, adherence to exoskeletons of the planktonic crustacean Daphnia pulex. The effect of the mutation was more pronounced for V. cholerae O139, essentially eliminating adherence. Adherence of the V. cholerae O1 classical mshA mutant was unaffected. The results suggest that MSHA is a factor contributing to the ability of V. cholerae to adhere to plankton. The results also showed that both biotypes of V. cholerae O1 utilize factors in addition to MSHA for zooplankton adherence. The expression of MSHA and these additional, yet to be defined, adherence factors differ in a serogroup- and biotype-specific manner.

In vivo measurement of unattached radon progeny deposited in the human respiratory tract

Seven nose breathing and seven mouth breathing volunteers were exposed to atmospheres enriched with unattached radon progeny (218Po, 214Pb and 214Bi). The activity of these radionuclides deposited in the respiratory tract was measured in vivo after the exposures. The results of these measurements are in agreement with predictions calculated with the ICRP Publication 66 Human Respiratory Tract Model. Temporal analysis of the activity deposited in the heads of the volunteers leads to the conclusion that a significant amount of the deposited activity associated with particle diameters of about 1 nm is not subject to a fast transport to the gastrointestinal tract as generally reported for larger aerosol particles.

Pretransplantation surveillance for possible hepatocellular carcinoma in patients with cirrhosis: epidemiology and CT-based tumor detection rate in 430 cases with surgical pathologic correlation

PURPOSE

To determine the prevalence of clinically unsuspected hepatocellular carcinoma (HCC) with advanced cirrhosis and assess the sensitivity of helical computed tomographic (CT) surveillance for tumor detection in these patients.

MATERIALS AND METHODS

Prospective direct correlation of CT findings with explanted liver specimen findings was performed in 430 transplant recipients with cirrhosis. The prevalence of clinically unsuspected HCC according to liver disease cause was evaluated. Serum alpha-fetoprotein (AFP) values in patients with and those without tumor were recorded. Prospective and retrospective CT tumor detection was evaluated with respect to CT technique and time from CT to transplantation.

RESULTS

HCC was found in 59 (14%) of 430 transplant recipients without suspicion of tumor before referral for transplantation. HCC was most prevalent with hepatitis B (27%) and hepatitis C (22%). Serum AFP values were not sensitive for detection of most small tumors. With triphasic helical CT, the prospective and retrospective rates of identifying patients with tumor were 59% and 68%, respectively; the prospective and retrospective tumor nodule detection rates were 37% and 44%, respectively. Tumor detection rates were highest with CT performed within 67 days before transplantation.

CONCLUSION

Clinically unsuspected HCC is most prevalent with cirrhosis secondary to hepatitis B or C, and, when evaluated at CT, is best detected with triphasic contrast material-enhanced helical imaging performed within 67 days before transplantation.

Liver transplantation for hepatocellular carcinoma: a proposal of a prognostic scoring system

BACKGROUND

The current staging system of hepatocellular carcinoma established by the International Union Against Cancer and the American Joint Committee on Cancer does not necessarily predict the outcomes after hepatic resection or transplantation.

STUDY DESIGN

Various clinical and pathologic risk factors for tumor recurrence were examined on 344 consecutive patients who received hepatic transplantation in the presence of nonfibrolamellar hepatocellular carcinoma to establish a reliable risk scoring system.

RESULTS

Multivariate analysis identified three factors as independently significant poor prognosticators: 1) bilobarly distributed tumors, 2) size of the greatest tumor (2 to 5 cm and > 5 cm), and 3) vascular invasion (microscopic and macroscopic). Prognostic risk score (PRS) of each patient was calculated from the relative risks of multivariate analysis. The patients were grouped into five grades of tumor recurrence risk: grade 1: PRS = 0 to < 7.5; grade 2: PRS = 7.5 to < or = 11.0; grade 3: PRS > 11.0 to 15.0; grade 4: PRS > or = 15.0; and grade 5: positive node, metastasis, or margin. The proposed PRS system correlated extremely well with tumor-free survival after liver transplantation (100%, 61%, 40%, 5%, and 0%, from grades 1 to 5, respectively, at 5 years), but current pTNM staging did not.

CONCLUSIONS

1) Patients with grades 1 and 2 are effectively treated with liver transplantation, 2) patients with grades 4 and 5 are poor candidates for liver transplantation, and 3) patients with grade 1 do not benefit from adjuvant chemotherapy.

Is the pathologic TNM staging system for patients with hepatoma predictive of outcome?

BACKGROUND

The pathologic TNM (pTNM) staging system was designed to aid in determining the prognosis of cancer patients and in planning and evaluating their treatment. The current pTNM classification system was not found to be predictive for patients undergoing orthotopic liver transplantation (OLTx) in the presence of hepatocellular carcinoma (HCC). Therefore, the authors examined the current system to determine whether improvements would allow the development of a more predictive system.

METHODS

Three hundred seven patients with HCC underwent OLTx between 1981 and 1997. Risk factors for recurrence were identified using the Kaplan-Meier method with the log rank test. The Cox proportional hazards model was used to identify factors independently predictive of recurrence which were then used to create a new staging system.

RESULTS

There was neither a direct correlation between the current pTNM system and tumor free survival nor homogeneity in outcomes for patients within certain current pTNM categories. Depth of vascular invasion, lobar distribution, lymph node status, and largest tumor size were found to be independent predictors of tumor free survival; tumor number was not found to be significant in multivariate analysis. A new staging system is proposed, which takes into account the results of the multivariate analysis in which tumor free survival correlates directly with stage.

CONCLUSIONS

The proposed staging system is superior to the current pTNM staging system in predicting tumor free survival following OLTx with HCC. Further studies will determine the appropriateness of this system for staging HCC after subtotal hepatic resection.

Is the pathologic TNM staging system for patients with hepatoma predictive of outcome?

BACKGROUND

The pathologic TNM (pTNM) staging system was designed to aid in determining the prognosis of cancer patients and in planning and evaluating their treatment. The current pTNM classification system was not found to be predictive for patients undergoing orthotopic liver transplantation (OLTx) in the presence of hepatocellular carcinoma (HCC). Therefore, the authors examined the current system to determine whether improvements would allow the development of a more predictive system.

METHODS

Three hundred seven patients with HCC underwent OLTx between 1981 and 1997. Risk factors for recurrence were identified using the Kaplan-Meier method with the log rank test. The Cox proportional hazards model was used to identify factors independently predictive of recurrence which were then used to create a new staging system.

RESULTS

There was neither a direct correlation between the current pTNM system and tumor free survival nor homogeneity in outcomes for patients within certain current pTNM categories. Depth of vascular invasion, lobar distribution, lymph node status, and largest tumor size were found to be independent predictors of tumor free survival; tumor number was not found to be significant in multivariate analysis. A new staging system is proposed, which takes into account the results of the multivariate analysis in which tumor free survival correlates directly with stage.

CONCLUSIONS

The proposed staging system is superior to the current pTNM staging system in predicting tumor free survival following OLTx with HCC. Further studies will determine the appropriateness of this system for staging HCC after subtotal hepatic resection.

Is the pathologic TNM staging system for patients with hepatoma predictive of outcome?

BACKGROUND

The pathologic TNM (pTNM) staging system was designed to aid in determining the prognosis of cancer patients and in planning and evaluating their treatment. The current pTNM classification system was not found to be predictive for patients undergoing orthotopic liver transplantation (OLTx) in the presence of hepatocellular carcinoma (HCC). Therefore, the authors examined the current system to determine whether improvements would allow the development of a more predictive system.

METHODS

Three hundred seven patients with HCC underwent OLTx between 1981 and 1997. Risk factors for recurrence were identified using the Kaplan-Meier method with the log rank test. The Cox proportional hazards model was used to identify factors independently predictive of recurrence which were then used to create a new staging system.

RESULTS

There was neither a direct correlation between the current pTNM system and tumor free survival nor homogeneity in outcomes for patients within certain current pTNM categories. Depth of vascular invasion, lobar distribution, lymph node status, and largest tumor size were found to be independent predictors of tumor free survival; tumor number was not found to be significant in multivariate analysis. A new staging system is proposed, which takes into account the results of the multivariate analysis in which tumor free survival correlates directly with stage.

CONCLUSIONS

The proposed staging system is superior to the current pTNM staging system in predicting tumor free survival following OLTx with HCC. Further studies will determine the appropriateness of this system for staging HCC after subtotal hepatic resection.

Effect of dopamine infusion (3-30 microg/kg/min) on hepatic hemodynamics

BACKGROUND

While dopamine produces well-characterized dose-dependent effects on systemic hemodynamics, there is a paucity of information regarding its effects on hepatic hemodynamics. Infusion rates above 10 microg/kg/min are reported to produce significant vasoconstriction and impair organ perfusion. Therefore, donors are sometimes considered unsuitable when higher doses of dopamine are in use. The aim of this study was to determine the effect of increasing doses of dopamine on hepatic hemodynamics in a nonanesthetized swine model.

MATERIALS AND METHODS

Sixteen pigs were instrumented with indwelling catheters in a peripheral artery, peripheral vein, portal vein, and hepatic vein and flow probes around the portal vein and hepatic artery. After recovery, the following variables were measured 10 +/- 1 days postinstrumentation: hepatic arterial flow (HAF), portal venous flow (PVF), mean systemic arterial pressure (MAP), central venous pressure (CVP), portal venous pressure (PVP), hepatic venous pressure (HVP), heart rate (HR). Recordings were obtained at baseline and subsequently when dopamine was infused at rates of 3, 6, 12, 15, 21, and 30 microg/kg/min increasing at 1-h intervals.

RESULTS

HAF and PVF increased linearly over the entire infusion range, to 69 and 13% over baseline, respectively (P < 0.001, P < 0.05). Total hepatic blood flow rose 23% over baseline at the 30 microg/kg/min dosage (P < 0.01). MAP increased linearly 13% over the range 12 to 30 microg/kg/min (P < 0.001). CVP, HVP, and PVP did not change significantly. HR decreased from 12 to 15 microg/kg/min (P < 0.01), then increased from 15 to 30 microg/kg/min (P < 0.05).

CONCLUSION

These data show that dopamine infused at dosages of 3-30 microg/kg/min augments HAF, PVF, and THBF and that this effect is linear. These results suggest high-dose dopamine infusion does not disqualify a potential donor liver for transplantation.

Screening for cerebral aneurysm in patients with polycystic liver disease

BACKGROUND

Polycystic liver disease (PCLD) is an autosomal dominant disease characterized by multiple macrocystic lesions throughout the liver. The association between PCLD and cerebral aneurysm is well documented, and approximately 20% of patients with PCLD have demonstrable cerebral aneurysms at autopsy. The prevalence reported from autopsy series, however, may not reflect the true prevalence in patients with PCLD. We undertook this study to evaluate the prevalence and diagnosis of cerebral aneurysms in screening cerebral studies in patients with PCLD.

METHODS

Patients were identified by searching the hepatobiliary surgical service data base and hospital medical records. Hospital charts were reviewed to confirm presence of PCLD and to identify screening studies for cerebral aneurysms.

RESULTS

Ten patients with PCLD received screening studies of the cerebral vasculature during a 10 1/2-year period. One patient was found to have an asymptomatic cerebral aneurysm. A 45-year-old woman with no other significant medical history was referred for evaluation of PCLD. Screening magnetic resonance angiography (MRA) revealed a 5 mm aneurysm extending anteriorly near the origin of the right ophthalmic artery, without evidence of rupture. Cerebral angiography confirmed these findings, and the aneurysm was clipped.

CONCLUSIONS

Because cerebral aneurysms can be an important source of morbidity and mortality in PCLD, we recommend screening by MRA or by computed tomographic angiography (CTA) of the cerebral vasculature in all patients who have PCLD.

Should hepatomas be treated with hepatic resection or transplantation?

BACKGROUND

The aim of this collaborative study was to compare the long term results of hepatic resection (Hx) with those of orthotopic liver transplantation (OLTx) in large numbers of cirrhotic patients with hepatocellular carcinoma (HCC) and to delineate the roles of these two surgical treatments.

METHODS

The databases of the National Cancer Center Hospital in Japan and the University of Pittsburgh Medical Center in the U. S. were exchanged and 294 cirrhotic patients who underwent curative Hx and 270 cirrhotic patients who underwent curative OLTx were selected for comparison.

RESULTS

The mortality rate within 30 days and that within 150 days after Hx were significantly lower than those after OLTx (P = 0.001 and P = 0.00007, respectively). Overall survival was similar between the Hx group and the OLTx group (P = 0.40). When compared in the HCC patients without macroscopic vascular invasion and lymph node metastases, the overall survival rate after OLTx was significantly higher than that after Hx (P = 0.006). However, this difference was not significant between the patients with Child-Pugh Grade A tumors in the Hx group and all patients (majority with Child-Pugh Grade C tumors) in the OLTx group (P = 0.25). Tumor free survival after OLTx was significantly higher than that after Hx (P < 0.0001), particularly in HCCs measuring </=5 cm, unilobarly distributed tumors, and HCCs with either no or only microscopic vascular invasion. In HCCs measuring > 5 cm and those with macroscopic vascular invasion, the tumor free survival rate was similar between the Hx group and the OLTx group.

CONCLUSIONS

In the face of organ shortage, HCC developing in a well compensated cirrhotic liver initially may be treated with Hx. However, the authors believe OLTx should be applied selectively to those patients with tumor recurrence and/or progressive hepatic failure.

Should hepatomas be treated with hepatic resection or transplantation?

BACKGROUND

The aim of this collaborative study was to compare the long term results of hepatic resection (Hx) with those of orthotopic liver transplantation (OLTx) in large numbers of cirrhotic patients with hepatocellular carcinoma (HCC) and to delineate the roles of these two surgical treatments.

METHODS

The databases of the National Cancer Center Hospital in Japan and the University of Pittsburgh Medical Center in the U. S. were exchanged and 294 cirrhotic patients who underwent curative Hx and 270 cirrhotic patients who underwent curative OLTx were selected for comparison.

RESULTS

The mortality rate within 30 days and that within 150 days after Hx were significantly lower than those after OLTx (P = 0.001 and P = 0.00007, respectively). Overall survival was similar between the Hx group and the OLTx group (P = 0.40). When compared in the HCC patients without macroscopic vascular invasion and lymph node metastases, the overall survival rate after OLTx was significantly higher than that after Hx (P = 0.006). However, this difference was not significant between the patients with Child-Pugh Grade A tumors in the Hx group and all patients (majority with Child-Pugh Grade C tumors) in the OLTx group (P = 0.25). Tumor free survival after OLTx was significantly higher than that after Hx (P < 0.0001), particularly in HCCs measuring </=5 cm, unilobarly distributed tumors, and HCCs with either no or only microscopic vascular invasion. In HCCs measuring > 5 cm and those with macroscopic vascular invasion, the tumor free survival rate was similar between the Hx group and the OLTx group.

CONCLUSIONS

In the face of organ shortage, HCC developing in a well compensated cirrhotic liver initially may be treated with Hx. However, the authors believe OLTx should be applied selectively to those patients with tumor recurrence and/or progressive hepatic failure.

Should hepatomas be treated with hepatic resection or transplantation?

BACKGROUND

The aim of this collaborative study was to compare the long term results of hepatic resection (Hx) with those of orthotopic liver transplantation (OLTx) in large numbers of cirrhotic patients with hepatocellular carcinoma (HCC) and to delineate the roles of these two surgical treatments.

METHODS

The databases of the National Cancer Center Hospital in Japan and the University of Pittsburgh Medical Center in the U. S. were exchanged and 294 cirrhotic patients who underwent curative Hx and 270 cirrhotic patients who underwent curative OLTx were selected for comparison.

RESULTS

The mortality rate within 30 days and that within 150 days after Hx were significantly lower than those after OLTx (P = 0.001 and P = 0.00007, respectively). Overall survival was similar between the Hx group and the OLTx group (P = 0.40). When compared in the HCC patients without macroscopic vascular invasion and lymph node metastases, the overall survival rate after OLTx was significantly higher than that after Hx (P = 0.006). However, this difference was not significant between the patients with Child-Pugh Grade A tumors in the Hx group and all patients (majority with Child-Pugh Grade C tumors) in the OLTx group (P = 0.25). Tumor free survival after OLTx was significantly higher than that after Hx (P < 0.0001), particularly in HCCs measuring </=5 cm, unilobarly distributed tumors, and HCCs with either no or only microscopic vascular invasion. In HCCs measuring > 5 cm and those with macroscopic vascular invasion, the tumor free survival rate was similar between the Hx group and the OLTx group.

CONCLUSIONS

In the face of organ shortage, HCC developing in a well compensated cirrhotic liver initially may be treated with Hx. However, the authors believe OLTx should be applied selectively to those patients with tumor recurrence and/or progressive hepatic failure.

Hepatic resection for metastatic colorectal adenocarcinoma: a proposal of a prognostic scoring system

BACKGROUND

Hepatic resection for metastatic colorectal cancer provides excellent longterm results in a substantial proportion of patients. Although various prognostic risk factors have been identified, there has been no dependable staging or prognostic scoring system for metastatic hepatic tumors.

STUDY DESIGN

Various clinical and pathologic risk factors were examined in 305 consecutive patients who underwent primary hepatic resections for metastatic colorectal cancer. Survival rates were estimated by the Cox proportional hazards model using the equation: S(t) = [So(t)]exp(R-Ro), where So(t) is the survival rate of patients with none of the identified risk factors and Ro = 0.

RESULTS

Preliminary multivariate analysis revealed that independently significant negative prognosticators were: (1) positive surgical margins, (2) extrahepatic tumor involvement including the lymph node(s), (3) tumor number of three or more, (4) bilobar tumors, and (5) time from treatment of the primary tumor to hepatic recurrence of 30 months or less. Because the survival rates of the 62 patients with positive margins or extrahepatic tumor were uniformly very poor, multivariate analysis was repeated in the remaining 243 patients who did not have these lethal risk factors. The reanalysis revealed that independently significant poor prognosticators were: (1) tumor number of three or more, (2) tumor size greater than 8 cm, (3) time to hepatic recurrence of 30 months or less, and (4) bilobar tumors. Risk scores (R) for tumor recurrence of the culled cohort (n = 243) were calculated by summation of coefficients from the multivariate analysis and were divided into five groups: grade 1, no risk factors (R = 0); grade 2, one risk factor (R = 0.3 to 0.7); grade 3, two risk factors (R = 0.7 to 1.1); grade 4, three risk factors (R= 1.2 to 1.6); and grade 5, four risk factors (R > 1.6). Grade 6 consisted of the 62 culled patients with positive margins or extrahepatic tumor. Kaplan-Meier and Cox proportional hazards estimated 5-year survival rates of grade 1 to 6 patients were 48.3% and 48.3%, 36.6% and 33.7%, 19.9% and 17.9%, 11.9% and 6.4%, 0% and 1.1%, and 0% and 0%, respectively (p < 0.0001).

CONCLUSIONS

The proposed risk-score grading predicted the survival differences extremely well. Estimated survival as determined by the Cox proportional hazards model was similar to that determined by the Kaplan-Meier method. Verification and further improvements of the proposed system are awaited by other centers or international collaborative studies.

HIV-1 Nef increases T cell activation in a stimulus-dependent manner

Lentiviral Nef increases viral replication in vivo, plays a direct role in pathogenesis, and increases viral particle infectivity. We now find that HIV Nef also increases the activation of T cells, a cellular state required for optimal viral replication. This enhancement is stimulant-dependent. As defined by IL-2 generation, activation of T cells stimulated with classical mitogens [phorbol 12-myristate 13-acetate (PMA) + anti-CD3, PMA + phytohemagglutinin, and PMA + ionomycin] is unaffected by the expression of Nef. However, Nef increases IL-2 secretion when cells are stimulated through the T cell receptor and the costimulus receptor (CD28). This increase in activation, which depends on Nef myristylation, is caused by an increase in the number of cells reaching full activation and not by an increase in the amount of IL-2 secreted per cell. These findings demonstrate that Nef lowers the threshold of the dual-receptor T cell activation pathway. The capacity of Nef to increase T cell activity may be very important in vivo when Nef is the predominant or the only viral gene product expressed.

Surgical experience with hepatic colorectal metastasis

The outcome of 134 patients undergoing hepatic resection for colorectal metastasis was studied. Current follow-up was available in 98 per cent of patients, for more than 5 years in 58 patients, and totaling 360 patient-years. Patients (52% male) had an average age of 62 +/- 1 years (standard error of the mean). Time lapse between the primary colon surgery and hepatic resection was a median of 16 months and a mean of 19 +/- 1 months. Thirty-two (24%) were operated on within 6 months for both their primary tumor and hepatic metastasis. Intensive care unit and total hospital length of stay were a median of 1 and 7 days, respectively. Pathology reports demonstrated that on average there were 2.0 +/- 0.1 lesions, with the largest lesion measuring 4.4 +/- 0.2 cm. In 72 per cent of patients, the lesions were found in one lobe only. CEA was elevated in 83 per cent of patients preoperatively and was 60 +/- 11 ng/mL before and 4.0 +/- 0.5 ng/mL after hepatic resection. Patient survival was 81 per cent at 1 year, 50 per cent at 3 years, 36 per cent at 5 years, and 23 per cent at 10 years. Actual 5- and 10-year survival was 22 of 58 (38%) patients and 4 of 21 (19%) patients respectively. Disease-free survival was 58 per cent at 1 year, 27 per cent at 3 years, 16 per cent at 5 years, and 12 per cent at 7 years. Survival was much better for one to four lesions than for five or more lesions (P < 0.01). Several other potential risk factors did not affect survival, including whether the patient received chemotherapy after hepatic resection. There were 36 (43%) patients who recurred with hepatic involvement only, 27 (32%) including hepatic involvement and 21 (25%) with nonhepatic involvement only. There were 15 patients who went on to receive repeat hepatic resections, with a 5-year survival of 74 per cent and disease-free survival of 58 per cent. Hepatic resection provides the best outcome of any form of therapy for selected patients with isolated hepatic metastasis.

A prospective, randomized trial of tacrolimus/prednisone versus tacrolimus/prednisone/mycophenolate mofetil in renal transplant recipients

BACKGROUND

Between September 20, 1995 and September 20, 1997, 208 adult patients undergoing renal transplantation were randomized to receive tacrolimus/prednisone (n=106) or tacrolimus/prednisone/mycophenolate mofetil (n=102), with the goal of reducing the incidence of rejection.

METHODS

The mean recipient age was 50.7+/-13.7 years. Sixty-three (30.3%) patients were 60 years of age or older at the time of transplantation. The mean donor age was 34.5+/-21.7 years. The mean cold ischemia time was 30.5+/-9.2 hr. The mean follow-up is 15+/-7 months.

RESULTS

The overall 1-year actuarial patient survival was 94%; the overall 1-year actuarial graft survival was 87%. When the patient and graft survival data were stratified to recipients under the age of 60 who did not have delayed graft function, the overall 1-year actuarial patient survival was 97%, and the corresponding 1-year actuarial graft survival was 93%. There were no differences between the two groups. The overall incidence of rejection was 36%; in the double-therapy group, it was 44%, whereas in the triple therapy group, it was 27% (P=0.014). The mean serum creatinine was 1.6+/-0.8 mg/dl. A total of 36% of the successfully transplanted patients were taken off prednisone; 32% of the patients were taken off antihypertensive medications. The incidence of delayed graft function was 21%, the incidence of cytomegalovirus was 12.5%, and the initial and final incidences of posttransplant insulin-dependent diabetes mellitus were 7.0% and 2.9%; again, there was no difference between the two groups.

CONCLUSIONS

This trial suggests that the combination of tacrolimus, steroids, and mycophenolate mofetil is associated with excellent patient and graft survival and a lower incidence of rejection than the combination of tacrolimus and steroids.

Hepatobiliary malignancies. Primary hepatic malignant neoplasms

Primary hepatic tumors are epithelial, mesenchymal, or mixed in origin. Of these, epithelial tumors are the most common and include hepatocellular carcinoma, cholangiocarcinoma, mixed hepatocholangiocarcinoma, hepatoblastoma, and a variety of more rare tumors. Hepatocellular carcinoma, also know as hepatoma or malignant hepatoma, is the most common, followed by cholangiocarcinoma. This article discusses these two malignancies.

Genetic and transcriptional analyses of the Vibrio cholerae mannose-sensitive hemagglutinin type 4 pilus gene locus

The mannose-sensitive hemagglutinin (MSHA) of the Vibrio cholerae O1 El Tor biotype is a member of the family of type 4 pili. Type 4 pili are found on the surface of a variety of gram-negative bacteria and have demonstrated importance as host colonization factors, bacteriophage receptors, and mediators of DNA transfer. The gene locus required for the assembly and secretion of the MSHA pilus has been localized to a 16.7-kb region of the V. cholerae chromosome. Sixteen genes required for hemagglutination, including five that encode prepilin or prepilin-like proteins, have been identified. Examination of MSHA-specific cDNAs has localized two promoters that drive expression of these genes. This evidence indicates that the MSHA gene locus is transcriptionally organized into two operons, one encoding the secretory components and the other encoding the structural subunits, an arrangement unique among previously characterized type 4 pilus loci. The genes flanking the MSHA locus encode proteins that show homology to YhdA and MreB of Escherichia coli. In E. coli, the yhdA and mreB genes are adjacent to each other on the chromosome. The finding that the MSHA locus lies between these two E. coli homologs and that it is flanked by a 7-bp direct repeat suggests that the MSHA locus may have been acquired as a mobile genetic element.

Undetected hepatocellular carcinoma: clinical features and outcome after liver transplantation

The aim of the study was to define the clinical characteristics and outcome of patients found to have an undetected hepatocellular carcinoma (HCC) at liver transplantation. Patients who underwent liver transplantation and were found to have a hepatoma with a prior workup showing normal alpha-fetoprotein levels and no corresponding lesion on radiological evaluation were defined as having an undetected HCC. Detailed information was collected, and the last abdominal computed tomographic (CT) scan before transplantation was performed was retrospectively reviewed. Thirty-nine patients had a tumor that met the criteria for an undetected hepatoma. The most common causes for pretransplantation liver disease were hepatitis C virus (HCV) (49%) and alcohol use (28%). Tumor size was 2 cm or less in 85% of the patients, vascular invasion was detected in 31% of the patients, and tumor, node, metastasis (TNM) classification was stage I or II in 77% of the patients. Review of the last CT scan before transplantation showed that the lesion was evident in retrospect in only 15% of the patients. Thirty-two patients (82%) remained alive at the time of the study with a mean follow-up of 30 months. Metastatic HCC was detected in 1 patient 7 months after transplantation. There were no other tumor recurrences. Survival analysis showed no significant differences when tumor size, stage, presence of vascular invasion, or causes of pretransplantation liver disease were compared. Undetected HCCs represent a significant percentage of total hepatomas in patients undergoing liver transplantation. Most patients have small, early-stage tumors, but tumors greater than 2 cm or of advanced stage are also frequently found in this population. Overall and tumor-free survival appear to be favorable.

Treatment of hilar cholangiocarcinoma (Klatskin tumors) with hepatic resection or transplantation

BACKGROUND

Because of the rarity of hilar cholangiocarcinoma, its prognostic risk factors have not been sufficiently analyzed. This retrospective study was undertaken to evaluate various pathologic risk factors which influenced survival after curative hepatic resection or transplantation.

METHODS

Between 1981 and 1996, 72 patients (43 males and 29 females) with hilar cholangiocarcinoma underwent hepatic resection (34 patients) or transplantation (38 patients) with curative intent. Medical records and pathologic specimens were reviewed to examine the various prognostic risk factors. Survival was calculated by the method of Kaplan-Meier using the log rank test with adjustment for the type of operation. Survival statistics were calculated first for each kind of treatment separately, and then combined for the calculation of the final significance value.

RESULTS

Survival rates for 1, 3, and 5 years after hepatic resection were 74%, 34%, and 9%, respectively, and those after transplantation were 60%, 32%, and 25%, respectively. Univariate analysis revealed that T-3, positive lymph nodes, positive surgical margins, and pTNM stage III and IV were statistically significant poor prognostic factors. Multivariate analysis revealed that pTNM stage 0, I, and II, negative lymph node, and negative surgical margins were statistically significant good prognostic factors. For the patients in pTNM stage 0-II with negative surgical margins, 1-, 3-, and 5-year survivals were 80%, 73%, and 73%, respectively. For patients in pTNM stage IV-A with negative lymph nodes and surgical margins, 1-, 3-, and 5-year survivals were 66%, 37%, and 37%, respectively.

CONCLUSIONS

Satisfactory longterm survivals can be obtained by curative surgery for hilar cholangiocarcinoma either with hepatic resection or liver transplantation. Redefining pTNM stage III and IV-A is proposed to better define prognosis.

Identification of the Vibrio cholerae type 4 prepilin peptidase required for cholera toxin secretion and pilus formation

Cholera toxin secretion is dependent upon the extracellular protein secretion apparatus encoded by the eps gene locus of Vibrio cholerae. Although the eps gene locus encodes several type four prepilin-like proteins, the peptidase responsible for processing these proteins has not been identified. This report describes the identification of a prepilin peptidase from the V. cholerae genomic database by virtue of its homology with the PilD prepilin peptidase of Pseudomonas aeruginosa. Plasmid disruption or deletion of this peptidase gene in either EI Tor or classical V. cholerae O1 biotype strains results in a dramatic decrease in cholera toxin secretion. In the case of the EI Tor biotype mutants, surface expression of the type 4 pilus responsible for mannose-sensitive haemagglutination is abolished. The cloned V. cholerae peptidase processes either EpsI or MshA preproteins when co-expressed in E. coli. Mutation of the V. cholerae peptidase gene also results in a defect in virulence and decreased levels of OmpU. The V. cholerae peptidase gene sequence shows 80% homology with the Vibrio vulnificus VvpD type 4 prepilin peptidase required for pilus assembly and cytolysin secretion in V. vulnificus. Accordingly, the V. cholerae type 4 prepilin peptidase required for pilus assembly and cholera toxin secretion has been designated VcpD.