Biomedical subjects

I Sirovich

Publications and source records attributed to I Sirovich.

8 recordsLinked to original sources

PubMed1996

Role of Kupffer cells in arresting circulating tumor cells and controlling metastatic growth in the liver.

Metastasis to the liver is a common event in clinical oncology. Blood-borne tumor cells (TCs) arriving to the liver sinusoids run into a special vascular bed. The lining of liver sinusoids is shared by Kupffer cells (KCs) and endothelial cells. KCs, liver-fixed macrophages, are responsible for detection and removal of "non-self" particles. To investigate their role in arresting blood-borne TCs and controlling tumor growth, we injected a syngeneic colon carcinoma cell line into a mesenteric vein of two groups of rats; one group was without Kupffer cells and the other normal controls. We removed the liver of these animals at different time intervals and performed immunohistochemical analysis with monoclonal antibodies (MoAbs) against our tumor cell line, three macrophage subpopulations, natural killer cells, and B and T lymphocytes. Additionally, we showed in vitro spontaneous cytotoxicity of KCs against our tumor cell line. Results suggest that KCs play a relevant role in arresting circulating TCs at the liver sinusoid, although it is limited to a small number of malignant cells. They also seem to play a major role in clearing neoplastic cells from the liver parenchyma, in controlling tumor growth in the very early stages of metastatic development, and in modulating the host immune response to cancer cells.

Animals↗

PubMed1995

The combination 5-fluorouracil/levamisole induces enhanced rat Kupffer cell-mediated cytotoxicity in vitro against the syngeneic colon adenocarcinoma cell line CC531.

The mode of action of the combination treatment 5-fluorouracil (5-FU) and levamisole in colorectal cancer patients is unknown. It is postulated that the beneficial effect may be explained by an immunomodulatory effect on Kupffer cell (KC) cytotoxicity. We evaluated the effect of levamisole (200 micrograms/ml) and 5-FU (10 microM) on rat KC cytotoxicity against syngeneic CC531 tumor cells. Viability of KCs was unaffected by 5-FU and/or levamisole. The combination did not enhance growth inhibition of CC531 compared to 5-FU alone. A significant increase in KC cytotoxicity was observed after 24-hr incubation with 5-FU/levamisole especially at an effector/target ratio of 10 (P < 0.05). 5-FU alone had no effect on KC cytotoxicity, while levamisole induced only a slight increase. Our in vitro data suggest that the additive effect of the combination 5-FU/levamisole on KC cytotoxicity may attribute to the beneficial effect of the adjuvant treatment in colorectal cancer patients.

Adenocarcinoma↗

PubMed1994

Systemic specific active immunotherapy for solid tumors. An overview about cancer vaccinetherapy.

Augmentation of specific immunity is one of the most promising immunotherapeutical approaches against solid tumors. Protocols using autologous tumor cells or tumor associated antigens are easily performed and not charged by severe side effects. Recently some clinical trials suggested good results from immunotherapeutical protocols applied as an adjuvant to surgery in terms of disease free interval, survival and progression time in different stages. In this review the authors report the results of the most important clinical trials of vaccinetherapy in solid tumors. Little is known about the possibility of this new approach to oncology since we are at the real beginning of a new clinical treatment but in the considered trial its effectiveness seems to suggest a future wider application.

Colonic Neoplasms↗

PubMed1993

Isolation of cytotoxic Kupffer cells by a modified enzymatic assay: a methodological study.

Kupffer cell (KC)-mediated cytotoxicity against tumor cells is of interest, since the liver is a major site of metastatic growth of primary colorectal cancer. KC isolation methods from rat livers, to study the tumoricidal properties of these cells, are based on perfusion of the liver and are therefore not suitable for human KC isolation from liver biopsies. In view of application to isolate KC from small wedge human liver biopsies, we have developed an isolation procedure for rat KC that does not require perfusion techniques. Liver tissue fragments were incubated with pronase with continuous pH registration and neutralization. KC were subsequently separated from other non-parenchymal cells by Nycodenz gradient centrifugation and purified by counterflow centrifugal elutriation. KC and other non-parenchymal cells were identified by immunophenotyping with a cytoplasmic monoclonal antibody ED1 and by ultrastructural analysis. About 3 x 10(6) KC per gram liver were isolated with a final purity of > 95% without loss of viability. To ensure that functionally competent KC were isolated, we assayed cytotoxicity against CC531 tumor cells in a recent developed cell-mediated MTT assay. Maximum cytotoxicity of KC was approximately 40% at an effector to target ratio of 10. In conclusion our approach seems to be a useful and simple method to isolate KC with good functional properties from rat livers, without the need for perfusion techniques.

Animals↗

PubMed1991

[Surgery by exeresis for gastric carcinoma. An analysis of 165 consecutive cases].

Surgery is still considered the best approach in gastric cancer. The aim of this study was to identify the most important factors involved in the determination of long-term survival. Total and subtotal gastrectomy were analysed. Long-term survival in these patients was strictly correlated with the stage of disease and the infiltration of resection margins. Early diagnosis is confirmed to be the most important factor in the long-term survival of these patients.

Carcinoma↗

PubMedDate not supplied

Activity of ruboxyl, a nitroxyl derivative of daunorubicin, on experimental models of colorectal cancer metastases.

We evaluated the activity of ruboxyl (Rbx), a nitroxyl analogue of daunorubicin (Dauno), in experimental models of hepatic metastases from colorectal carcinoma (CRC) and compared it with its parent compound and with 5-fluorouracil (5FU). In mice treated by intraperitoneal injections Rbx and 5FU proved more effective than Dauno: the Index of Inhibition of Metastases in comparison with controls was 43% for Dauno, 70% for 5FU and 84% for Rbx. In BDIX rats implanted with the syngeneic cell line DHD K12/TRb, both Rbx and 5FU, administered as a continuous intravenous infusion for 7 days, reduced the development of liver metastases from a median of 23.8 +/- 2.16 for controls to 3.2 +/- 1.3 for 5FU and 1.0 +/- 1.4 for Rbx (p < 0.0001 versus controls for both treatments): the comparison of Rbx and 5FU showed a trend in favour of this new anthracycline. Median survival was prolonged from 40.6 +/- 3.4 days in controls to 56.0 +/- 5.8 days with Rbx and 58.0 +/- 4.69 days with 5FU. Considering that in a phase I study Rbx showed only minor and manageable toxic side effect, its activity in the clinical treatment of CRC metastases may deserve further attention.

Adenocarcinoma↗

PubMedDate not supplied

[Infections in surgery].

In this paper the authors review current concepts on surgical infections. Topics covered are: hospital-acquired surgical infections, prognostic indexes, antibiotic prophylaxis, surveillance and control measures.

Anti-Bacterial Agents↗

PubMedDate not supplied

[Immunotherapy of solid tumors. Current status and prospects].

Immunotherapy is the most recent therapeutic strategy in the treatment of cancer. It has not yet achieved an elevated curative efficiency and a wide clinical application. Nevertheless the possibilities of improvement seem very promising. The knowledge of the immune response mechanisms and the first clinical trials have determined a more efficient immunotherapy. Here we will critically analyze current immunotherapeutic strategies by reviewing the latest and the most important experimental works. The latest protocols of immunotherapy have been aimed to be more integrated in the physiological immune response schemes. The orientation of the experimental works have been changed from non specific immunotherapy using lymphokines to immunotherapy with specific lymphocytes expanded in vitro and, finally, the active specific immunotherapy in vivo by modificated tumoral vaccines or by variously manipulated tumoral antigens.

Animals↗