Microbiological safety assessment of silkworm farms: a case study.

Silkworms have been farmed for their silk since ancient times. After silk reeling, their chrysalides are consumed as food in several Asian countries. Despite the long rearing tradition of this insect, few studies have investigated the silkworm's microbiological safety all along the life cycle, focusing on detecting silkworm pathogens or on the safety of the dried chrysalis for food consumption. However, the in-farm rearing process, which takes around forty days, may affect the microbial load of the silkworm and of the rearing environment, as well as the quality of fresh cocoon and other performance parameters. No data is available on how microbial contamination changes during the rearing period and between different farmers. Furthermore, in light of the possible use of the chrysalis as food, it is crucial to understand how its microbial load varies according to the water content. To address these specific questions, we conducted an investigation involving the analysis of specific microbial indicators commonly used in the food chain. We collected environmental and silkworm samples from several farms. The examination covered the entire life cycle of silkworms, beginning with the first instar larvae and concluding with the scrutiny of both freshly harvested and dried pupae. Silkworm farms in Northeast Italy proved to be an appropriate model system for carrying out the experimentation. Additionally, an evaluation of rearing performance was conducted, with a focus on the quality of fresh cocoons and the survival rate of the insects.

Effect of diethyldithiocarbamate on toxicity of doxorubicin, cyclophosphamide and cis-diamminedichloroplatinum (II) on mice haemopoietic progenitor cells.

DBA/2NCr1BR F1 mice received a single i.v. injection of doxorubicin (4.32, 7.20 or 12.00 mg kg-1), cyclophosphamide (70, 120 or 200 mg kg-1) or cis-diamminechloroplatinum (5.4, 9.0 or 15.0 mg kg-1), alone or 2 h before an i.p. injection of 1,000 mg kg-1 of diethyldithiocarbamate (DDTC). Twenty-four hours after, survival of bone marrow colony forming units-spleen and granulocyte-macrophage colony forming cells, was determined. On the whole, administration of DDTC reduced the toxic effect of the three anticancer drugs on haemopoietic progenitors. The effect was in general more evident at the lower than at the higher doses of the antitumour drugs.

Azidothymidine-induced depression of murine hemopoietic progenitor cells.

The toxicity of the antiviral drug 3'-azido-3'-deoxythymidine was studied in vivo on murine hemopoietic progenitor cells and peripheral blood cells. The drug induced a marked decrease of all tested populations, showing a severe toxicity on hemopoiesis.

Effect of H2 antagonists cimetidine and famotidine on the hemotoxicity of cyclophosphamide.

A comparison between the effects of H2 antagonists Cimetidine and Famotidine on the hemotoxicity of Cyclophosphamide in vivo in DBA/2NCrBl mice is described. Hemotoxicity of anticancer drug was determined by peripheral blood leukocytes, bone marrow cells and bone marrow CFU-S, GM-CFC. Results show that Famotidine does not increase Cyclophosphamide hemotoxicity while Cimetidine enhances the toxicity of the anticancer drug only on normal pluripotent hemopoietic stem cells.

Studies on hemotoxicity of cyclophosphamide, doxorubicin and cis-diamminodichloroplatinum combined with sodium-2-mercaptoethane sulfonate.

The possible protective action of sodium-2-mercaptoethanesulfonate (mesna) on hemotoxicity induced by anticancer drugs was tested in normal mice. Mesna (100 mg/kg b.w.) was injected i.v. 1 h before the i.v. administration of cyclophosphamide (10, 120, and 200 mg/kg b.w.), doxorubicin (4.32, 7.2, and 12 mg/kg b.w.) and cis-diamminedichloroplatinum (5.4, 9, and 15 mg/kg b.w.). Results show that in this experimental model mesna does not seem to protect against toxicity of the tested anticancer drug on hemopoietic progenitor cells.

Toxicity of trimetrexate on hemopoietic progenitor cells in normal mice.

Single increasing doses of methotrexate (MTX) and trimetrexate (TMQ) were administered to normal mice. Survival of hemopoietic progenitor cells assayed as CFU-S and GM-CFC was determined 24 hr after drug injection. The survival of each population in TMQ-treated animals was not statistically different from that observed in mice treated with MTX. No difference was observed in time-survival curves of hemopoietic progenitor cells comparing TMQ to MTX. TMQ toxicity at the hematological level thus seems comparable to that of MTX.

Experimental comparative study on myelotoxicity of 4'-deoxy-4'-I-doxorubicin and of doxorubicin.

4'-Deoxy-4'-I-doxorubicin (I-Dx) is 1.5-2 times more potent than doxorubicin (Dx) on some mice tumors and does not seem to be cardiotoxic. A comparison was made of the effects of both anthracyclines on mice bone marrow hemopoietic progenitors (CFU-S, GM-CFC) and peripheral blood cells. The experimental model is based on dose survival and time survival curves following single or repeated (1 weekly administration for 4 weeks) doses. Results indicate slightly higher sensitivity of assayed populations to I-DX than to Dx.

Diltiazem does not increase the in vivo sensitivity of murine hemopoietic progenitor cells to doxorubicin.

The effect of doxorubicin and the calcium antagonist, diltiazem, on murine hemopoietic progenitor cells was studied in vivo. Dose-survival curves of murine bone marrow colony forming units (CFU)--spleen and granulocyte macrophage--were determined by in vivo and in vitro methods in DBA/2NCr/BR mice treated with doxorubicin alone or by simultaneous administration of doxorubicin (DX) and diltiazem (DTZ). Time response of bone marrow hematopoietic progenitor cells (HPC) was followed in mice similarly treated. Combination of DTZ with DX did not change the toxic effect of the latter on hemopoietic cells, either in the dose-survival model or in the time-related experiment.

Experimental study on bone marrow CFUs following anticancer drug administration to plethoric mice.

The effect of some cycle-dependent anticancer drugs on CFUs has been studied in transfused polycythemic mice. In untreated animals during passive plethora erythropoiesis is depressed but the content of CFUs per femur remains constant. In treated plethoric mice the femural content of CFUs is similar or higher than that found in treated controls after administration of adriamycin, vinblastine, cyclophosphamide, it is lower when the mice receive azathioprine or hydroxyurea. These results suggest that suppression of erythropoiesis does not uniformly affect the susceptibility of pluripotent stem cells to anticancer drugs. Interpretation of the reported findings is difficult as it must take into account a complex interplay of a number of factors.

The effects of chronic administration of cyclophosphamide on haemopoietic stem cells.

The effects of cyclophosphamide given for 18 weeks in small daily doses on CFU-S, CFU-C, and CFU-E content in mice bone marrow and spleen were studied. In the bone marrow, after an initial drop, the stem cell content rises above the normal values and remains there throughout a long period. In the spleen the stem cell content shows an initial several fold increase followed by a steady decline. It seems possible that this behaviour reflects a compensative effect to the toxic action of the drug at more differentiated levels of the haemopoietic cells.

Effect of bleeding on in vivo in vitro colony-forming hemopoietic cells.

The effect of bleeding on spleen colony-forming units (CFU-S) and on in vitro colony-forming cells with colony-stimulating factor (CFU-C) and erythropoietin (CFU-E) has been evaluated. The in vivo and in vitro colony-forming cells of the bone marrow show a decrease which for the CFU-E, CFU-C follows a short-lived increase. In the spleen, all progenitor cells assayed have shown a significant and sustained increase.

[Hematopoietic stem cells and antiblastic drugs. II. Variations in the colony forming cells in vivo after administration of peptichemio]. / Cellule staminali emopoietiche ed antiblastici. II. Variazioni delle cellule formatrici di colonie in vivo dopo somministrazione di peptichemio

Peptichemio, administered in a single LD50, dose, induces a significant reduction of mice bone marrow and spleen CFUs. The lesive action appears to be similar to that observed after a single dose of various antineoplastic agents. The effects of increasing doses of Peptichemio are also reported.