Ethanol-dependent induction of bilirubin UDP-glucuronosyl-transferase in rat liver is mediated by Kupffer cells

Recently we have reported that bilirubin UDP-glucuronosyltransferase (UGT1A1) is induced in rat liver by chronic ethanol treatment. Several studies have shown that Kupffer cells play a central role in the mediation of various hepatic effects of chronic alcohol consumption. In the present work, the participation of Kupffer cells in the ethanol dependent induction of UGT1A1 was investigated. A group of rats was pretreated with gadolinium chloride, a known Kupffer-cell-depleting agent. We compared the effect of chronic ethanol ingestion on UGT1A1 expression in the liver of normal and gadolinium chloride treated rats. The effect of ethanol on bilirubin glucuronidation was completely prevented in Kupffer cell deficient rats. The western and northern blot analyses showed that the increase of both the protein and mRNA of UGT1A1 was prevented in these animals. These results suggest that Kupffer cells play a major role in the mediation of ethanol-stimulated induction of UGT1A1 in liver parenchymal cells.     

Causal association between human papilloma virus infection and head and neck and esophageal squamous cell carcinoma

HPVs commonly cause proliferative lesions of squamous epithelium, and infection with certain HPV types carries a high risk of malignant transformation. We used molecular techniques to detect and type HPV in papillomas and carcinomas in the oral cavity and esophagus. DNA was extracted from 150 fresh or paraffin embedded biopsy specimens, and analyzed for HPV by PCR with 15 sets of consensus primers directed to conserved regions of L1 gene, three sets of HPV16E6 primers (specific for the HPV 16 prototype and L83V variant), and sets of primers specific for the E6 gene of other mucosa type HPVs including HPV 6, 11, 16, 18, 52, 58, 66 and 73. Overall, HPV sequences were detected in 61 of 150 specimens. HPV DNA sequences were detected in 16/32 specimens in the oropharyngeal region, in 13/36 specimens in larynx and 32/82 specimens in esophagus. Papillomas contained only the episomal form of HPV 16. In the esophagus, the most common type was HPV 73. In all specimens examined, HPV 6/11 (4/150), HPV 16 (23/150), HPV 35 (1/150), HPV 45 (1/150), HPV 54 (1/150), HPV 58 (1/150), HPV 61 (1/150), HPV 66 (1/150), HPV 68 (2/150), HPV 70 (3/150), HPV 72 (1/150), HPV 73 (16/150), double HPV infection (2/150), and unidentified HPV type (4/150) was detected. Interestingly, HPV was found in all verrucous carcinomas and in 18/22 basaloid squamous cell carcinomas. HPV16E6 T350G mutant were observed only in two of eight carcinomas. Using correspondence analysis, a segregation of specific virus types in specific clinico-pathologic lesions (verrucous carcinoma and basaloid squamous cell carcinoma) was proved. It was shown that the relative rates of the HPV positive tumors were significantly higher in women than in men. The synergic action of mucosal irritation and HPV infection may be necessary for the development of the papillomas and the specific types of carcinomas in the oral cavity and in the esophagus.     

Evolution of adjuvant chemotherapy of breast cancer from Bonadonna to the taxanes

The author summarizes the progress of adjuvant chemotherapy of breast cancer from the classical Bonadonna-type CMF over the anthracyclines to the taxanes. The CMF regimen represented the prototype of combination chemotherapy which significantly improved early and long term results. After 20 years the patients given adjuvant combination chemotherapy with CMF had significantly better rates of relapse-free survival (p<0.001) and overall survival (p=0.03) compared with no chemotherapy. 6 cycles of CMF was the gold standard of adjuvant chemotherapy in breast cancer for decades. The Milan research group decided in the early 1980s to challange this popular CMF combination by introducing doxorubicin within the adjuvant program. Compared with standard CMF, anthracyclin-containing regimens reduced the annual risk of recurrence by 12% and the annual risk of death by 11%, equating to a 3.2% absolute reduction in recurrence and a 2.7% absolute reduction in mortality at 5 years. This small but real difference seen with regimens containing three or more agents (e.g. CEF and CAF, FAC, FEC, etc.), whereas 4 cycles of 2-drug regimens (e.g. AC or EC) appears to be equivalent to 6 cycles of CMF. Among the novel chemotherapeutic drugs introduced in the 1990s the taxanes have emerged as the most powerful compounds in breast cancer. Several large, adjuvant clinical trials are currently ongoing or have recently completed accrual. The available results from innumerable clinical studies are still inconclusive and do not support the routine use of taxanes in the adjuvant setting - with the exception of the BCIRG 001 docetaxel trial, in which significant improvement was documented in disease free survival with 6 x TAC compared with 6 x FAC (82% vs 74%). Studies on the effect of the new trastuzumab (an antibody against the extracellular domain of the HER2) in adjuvant setting was initiated in early 2000. The Herceptin adjuvant trial programme is extensive, involving more than 12,000 patients worldwide. This trials will potentially offer many women with HER2-positive disease the chance of improved survival.     

Mannose-binding lectin (MBL) mutants are susceptible to matrix metalloproteinase proteolysis: potential role in human MBL deficiency

Mannose-binding lectin (MBL) plays a critical role in innate immunity. Point mutations in the collagen-like domain (R32C, G34D, or G37E) of MBL cause a serum deficiency, predisposing patients to infections and diseases such as rheumatoid arthritis. We examined whether MBL mutants show enhanced susceptibility to proteolysis by matrix metalloproteinases (MMPs), which are important mediators in inflammatory tissue destruction. Human and rat MBL were resistant to proteolysis in the native state but were cleaved selectively within the collagen-like domain by multiple MMPs after heat denaturation. In contrast, rat MBL with mutations homologous to those of the human variants (R23C, G25D, or G28E) was cleaved efficiently without denaturation in the collagen-like domain by MMP-2 and MMP-9 (gelatinases A and B) and MMP-14 (membrane type-1 MMP), as well as by MMP-1 (collagenase-1), MMP-8 (neutrophil collagenase), MMP-3 (stromelysin-1), neutrophil elastase, and bacterial collagenase. Sites and order of cleavage of the rat MBL mutants for MMP-2 and MMP-9 were: Gly(45)-Lys(46) --> Gly(51)-Ser(52) --> Gly(63)-Gln(64) --> Asn(80)-Met(81) which differed from that of MMP-14, Gly(39)-Leu(40) --> Asn(80)-Met(81), revealing that the MMPs were not functionally interchangeable. These sites were homologous to those cleaved in denatured human MBL. Hence, perturbation of the collagen-like structure of MBL by natural mutations or by denaturation renders MBL susceptible to MMP cleavage. MMPs are likely to contribute to MBL deficiency in individuals with variant alleles and may also be involved in clearance of MBL and modulation of the host response in normal individuals.     

T and B cell recovery in arthritis adoptively transferred to SCID mice: antigen-specific activation is required for restoration of autopathogenic CD4+ Th1 cells in a syngeneic system

T cell homeostasis is a physiological function of the immune system that maintains a balance in the numbers and ratios of T cells at the periphery. A self-MHC/self-peptide ligand can induce weak (covert) signals via the TCR, thus providing an extended lifespan for naive T cells. A similar mechanism is responsible for the restoration of immune homeostasis in severe lymphopenic conditions such as those following irradiation or chemotherapy, or upon transfer of lymphocytes to nu/nu or SCID mice. To date, the genetic backgrounds of donor and recipient SCID mice were unmatched in all autoimmune arthritis transfer experiments, and the recovery of lymphoid cells in the host has not been followed. In this study, we present the adoptive transfer of proteoglycan (PG)-induced arthritis using unseparated and T or B cell-depleted lymphocytes from arthritic BALB/c donors to genetically matched syngeneic SCID recipient mice. We demonstrate that selectively recovered lymphoid subsets determine the clinical and immunological status of the recipient. We found that when T cells were depleted (>98% depleted), B cells did not produce PG-specific anti-mouse (auto) Abs unless SCID mice received a second Ag (PG) injection, which promoted the recovery of Ag-specific CD4(+) Th1 cells. Reciprocally, as a result of B cell recovery, high levels of serum anti-PG Abs were found in SCID mice that received B cell-depleted (>99% depleted) T lymphocytes. Our results indicate a selective and highly effective cooperation between CD4(+) T cells and B lymphocytes that is required for the restoration of pathological homeostasis and development of autoimmune arthritis in SCID mice.     

Human immunodeficiency virus type 1-hepatitis C virus coinfection: intraindividual comparison of cellular immune responses against two persistent viruses

Both human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) lead to chronic infection in a high percentage of persons, and an expanding epidemic of HIV-1-HCV coinfection has recently been identified. These individuals provide an opportunity for simultaneous assessment of immune responses to two viral infections associated with chronic plasma viremia. In this study we analyzed the breadth and magnitude of the CD8(+)- and CD4(+)-T-lymphocyte responses in 22 individuals infected with both HIV-1 and HCV. A CD8(+)-T-lymphocyte response against HIV-1 was readily detected in all subjects over a broad range of viral loads. In marked contrast, HCV-specific CD8(+)-T-lymphocyte responses were rarely detected, despite viral loads in plasma that were on average 1,000-fold higher. The few HCV-specific responses that were observed were relatively weak and limited in breadth. CD4-proliferative responses against HIV-1 were detected in about half of the coinfected subjects tested, but no proliferative response against any HCV protein was found in these coinfected persons. These data demonstrate a major discordance in immune responses to two persistent RNA viruses. In addition, they show a consistent and profound impairment in cellular immune responses to HCV compared to HIV-1 in HIV-1-HCV-coinfected persons.     

Comparative analysis of anti-hepatitis C virus activity and gene expression mediated by alpha,beta, and gamma interferons

A direct comparison of the inhibitory effects of alpha, beta, and gamma interferons (IFNs) on replication of a hepatitis C virus subgenomic replicon in a hepatoma cell line revealed similarities in antiviral potency. However, alternate IFN-induced antiviral mechanisms were suggested following observations of striking differences between IFN-gamma and IFN-alpha/beta with respect to strength and durability of the antiviral response and the magnitude and pattern of IFN-mediated gene expression.