Adjuvant perioperative hepatic arterial mitomycin C and floxuridine combined with surgical resection of metastatic colorectal cancer in the liver

Twenty patients with colon cancer metastatic to the liver underwent successful hepatic resection and adjuvant perioperative therapy that included hepatic arterial mitomycin C and floxuridine (FUDR). The median survival for all 20 patients was 51 months: 10 are still alive with a median postoperative follow-up of 49 months; 6 are disease-free with a median postoperative follow-up of 43 months. Among 10 patients in whom the surgical margins of the specimen contained tumor cells, the median survival was 52 months. This survival was comparable to that among 10 patients in whom the surgical margins were tumor free (P = 0.22). Neither the number of metastatic liver deposits nor the disease-free interval between the primary diagnosis of colorectal carcinoma and the development of liver metastases significantly affected survival. A transient chemical hepatitis which resolved before the next scheduled treatment was associated with 50% of arterial chemotherapy cycles (approximately 70% of the patients). Gastric or duodenal ulcerations occurred in 23% of the patients. Surgical complications were either pulmonary such as pleural effusion or atelectasis, or wound infections and subphrenic abscesses. Although these results compare favorably with the results in previously published series, this aggressive adjuvant chemotherapy appears to be particularly justified in patients with tumor positive surgical margins or those with multiple tumor masses and, therefore, are characterized by a poor prognosis.     

Interleukin-4 downregulates interleukin-6 production in human peripheral blood mononuclear cells

We report that recombinant human interleukin-4 (IL-4) downregulates interleukin-6 (IL-6) production by human peripheral blood mononuclear cells (PBMC). PBMC were preincubated for up to 24 hr in the presence of IL-4 (100 U/ml) and then activated with lipopolysaccharide B Escherichia coli 026:B6 (LPS, 10 micrograms/ml), recombinant human tumor necrosis factor-alpha (TNF-alpha, 200 U/ml), or Concanavalin A (Con A, 10 micrograms/ml). Although all these signals induced IL-6 production, IL-4-treated cells produced significantly reduced levels of IL-6 protein. This effect was dose and time dependent. We conclude that IL-4 is a potent downregulatory modulator of IL-6 expression in human PBMC.     

Automated, quantitative cytopathic effect reduction assay for interferon.

A rapid, cytopathic effect reduction assay for human interferon (IFN) is described. Dilutions of IFN were made with an automated diluter in 96-well microtiter plates. Total incubation time was 26 h. IFN titers were calculated from optical density readings of crystal violet-stained monolayers in an automated spectrophotometer, which required less than 1 min to read each plate.     

The major surface protein complex of Treponema denticola depolarizes and induces ion channels in HeLa cell membranes.

The oral spirochete Treponema denticola is closely associated with periodontal diseases in humans. The 53-kDa major surface protein (Msp) located in the outer membrane of T. denticola serovar a (ATCC 35405) has both pore-forming activity and adhesin activity. We have used standard patch clamp recording methods to study the effects of a partially purified outer membrane complex containing Msp on HeLa cells. The Msp complex was free of the chymotrypsin-like proteinase also found in the outer membrane of T. denticola. Msp bound to several HeLa cell proteins, including a 65-kDa surface protein and a 96-kDa cytoplasmic protein. The Msp complex depolarized and increased the conductance of the HeLa cell membrane in a manner which was not strongly selective for Na+, K+, Ca2+, and Cl- ions. Cell-attached patches of HeLa cell membrane exposed to Msp complex exhibited short-lived channels with a slope conductance of 0.4 nS in physiologically normal saline. These studies show that Msp binds both a putative epithelial cell surface receptor and cytoplasmic proteins and that the Msp complex can form large conductance ion channels in the cytoplasmic membrane of epithelial cells. These properties may contribute to the cytopathic effects of T. denticola on host epithelial cells.     

Assessment of IgE-mediated sensitivity during immunotherapy: comparison of the RAST with and without adsorption of IgG to titrated prick skin tests

The effect of specific IgG induced by allergy immunotherapy on specific IgE binding in the RAST was assessed by removal of the IgG with staphylococcus protein A bound to Sepharose. In sera from those patients with the highest titers of specific IgG, RAST binding was increased 8% following adsorption of the post-immunotherapy sera while in sera obtained from the same patients before immunotherapy adsorption increased binding only 3%. The effect of allergy immunotherapy on the titrated prick skin test was compared to the effect on the RAST to the same allergen. In nine patients who received the highest dose of grass extract, the area of the titrated prick skin tests was reduced following immunotherapy by 75%. Staphylococcus protein-A adsorption of sera from these patients drawn before immunotherapy resulted in an increase in RAST binding of 2.7% compared to an increase of 6% in sera obtained after immunotherapy, suggesting suppression of RAST binding of only 3% by specific IgG. It is concluded that RAST levels are affected less than prick skin tests by the immunologic response to allergy immunotherapy. Some interference in RAST binding is produced by specific IgG antibody in high titers, but for many critical purposes the degree of interference is not significant.     

Differentiation status of rat ductal cells and ethionine-induced hepatic carcinomas defined with surface-reactive monoclonal antibodies

To gain further insight into the differentiation of oval cells and their role in carcinogenesis, we have generated cell surface reactive monoclonal antibodies (MAbs) by a Balb/c nude mouse (nu/nu) immunization protocol. Three MAbs designated OC.4, OC.5, and OC.10 were generated from a mouse immunized with CDE6, an oval cell line established from oval cells induced by feeding a choline-deficient diet containing 0.1% ethionine (CDE). These MAbs demonstrated stage-specific expression in fetal liver and displayed strong reactivity with oval and bile duct epithelial cells. In general, oval cells displayed a more mature phenotype than fetal ductal cells, suggesting the existence in adult liver of more primitive ductal progenitors. A fourth MAb recognized a cytoplasmic antigen (OC.6) expressed by mucus-secreting hepatic ducts induced by CDE diet. Immunocytochemical analysis indicated that OC.4, OC.5, and OC.10 were also expressed on CDE-induced, OV6+ hepatocellular carcinomas (HCC) but not on OV6+ HCC induced by the Solt/Farber protocol. In most cases, CDE-induced, OV6+ HCC expressed early ductal developmental markers such as OC.10 but lacked those expressed at later stages (OC.5, OC.4). These new MAb will be useful for characterizing HCC subpopulations with oval cell characteristics and for isolating biliary cells at antigenically defined stages during differentiation.     

Precise targeting of the pathology of the sialoglycoprotein, PrP, and vacuolar degeneration in mouse scrapie

Widespread immunostaining of PrP protein was demonstrated in scrapie mouse brain, distributed diffusely in the neuropil and focally in amyloid plaques, microglia and 2-5 microns structures resembling neuronal processes. With the 87V scrapie strain, which produces focal vacuolation in particular areas, PrP pathology was precisely targeted to these same areas, predating vacuolar degeneration by at least several weeks. On the other hand, both vacuolar and PrP changes were widely distributed throughout the brain with the ME7 scrapie strain. It is likely that the precise targeting of PrP pathology, followed by vacuolar degeneration, reflects an underlying targeting and localised replication of infectious agent.     

Longitudinal study of Plasmodium falciparum polymorphic antigens in a malaria-endemic population.

Plasmodium falciparum merozoite surface antigens MSP1 and MSP2 and an exported antigen, Exp-1, exhibit allelic polymorphism in natural populations. To explain this, one hypothesis is that antigen polymorphisms are maintained by frequency-dependent immune selection. An expectation of the hypothesis is that rare variants have an advantage over common variants because of a lower level of acquired immunity against them and thus increase in frequency until an equilibrium is attained. To test this hypothesis, the frequencies of polymorphic epitopes of MSP1, MSP2, and Exp-1 were determined among isolates from malaria patients in an urban area of The Gambia, during different periods of one transmission season (1988) and in different years (1982, 1983, 1988, and 1989). The frequencies remained very stable throughout the period of study, alternative epitope variants remaining either rare or common, without shifts in relative frequencies. These results are discussed with reference to the immune-selection hypothesis, with the conclusion that frequencies of the major dimorphic serological classes of MSP1 are probably not maintained by immune selection.     

Molecular cloning and characterization of the 120-kilodalton protein gene of Ehrlichia canis and application of the recombinant 120-kilodalton protein for serodiagnosis of canine ehrlichiosis

The 120-kDa outer membrane protein (p120) is a potential adhesin of Ehrlichia chaffeensis, and recombinant p120 is very useful for serodiagnosis of human monocytotropic ehrlichiosis. The analogous gene of p120 in Ehrlichia canis was cloned, sequenced, and expressed. Like the E. chaffeensis p120, the E. canis p120 contains tandem repeat units. However, neither the repeat number nor the amino acid sequences in the repeats are identical in the two Ehrlichia species. The repeat units are hydrophilic and by probability analysis are predicted to be surface exposed in both species. The repeat regions of the p120s of the two species have common amino acid sequences that are predicted to be surface exposed. The overall amino acid sequence of the E. canis p120 is 30% homologous to that of E. chaffeensis p120. Protein immunoblotting demonstrated that the recombinant E. canis p120 reacted with convalescent sera from dogs with canine ehrlichiosis. These results indicate that the recombinant p120 is a potential antigen for the serodiagnosis of canine ehrlichiosis.