Changes in thyroid hormone and thyrotrophin in the serum and thyroid glands of developing genetically obese male and female Zucker rats.

In a first experiment, serum thyroxine (T4), 3,5,3'-triiodothyronine (T3) and thyrotrophin (TSH) concentrations as well as thyroid gland T4 and T3 contents were measured in developing lean and obese Zucker male and female rats of 4-16 weeks of age. The rats were bred in our laboratory and always treated in sex-matched pairs of one lean and one obese rat from the same litter. Serum T4 was not different in any phenotype/sex group at 4 weeks. In male rats, it became progressively lower (27 and 37% at 12 and 16 weeks respectively) in obese than in lean rats. In females, similar levels of serum T4 were maintained in both obese and lean developing rats. Serum T3 was similar in obese and lean male 4-week-old rats whereas it was lower (28%) in obese than in lean females. It became progressively lower (39 and 49% at 12 and 16 weeks respectively) in obese than in lean developing male rats. In females, lower levels of serum T3 were maintained (25 and 43% at 12 and 16 weeks respectively) in obese than in lean rats. Serum TSH was not different in any phenotype/sex group at 4 weeks. It rose in both obese and lean male rats with age, but became progressively lower (33 and 23% at 12 and 16 weeks respectively) in obese compared with lean rats. In females, similar levels of serum TSH were maintained in both obese and lean developing rats. Thyroid gland weight was not different in any phenotype/sex group at 4 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of prolonged fasting and thyroid hormone on the alpha 2-adrenergic response in isolated epididymal adipocytes of Wistar rats.

Fasting and thyroid hormone have been reported to modulate the beta-adrenergic pathway of lipolysis in rat, but their effects on the alpha 2-adrenergic response are not well known. The purpose of the present study was to investigate this point. Male Wistar rats, 3 weeks old, were thyroidectomized surgically, kept for 1 month at 25 degrees C and then fasted or not fasted for 3 days with or without daily intraperitoneal injection of 3,5,3'-tri-iodo-L-thyronine (T3; 4.6 nmol/100 g body weight). Age-matched, sham-operated, fed and fasted euthyroid rats were used as controls. The experiments were carried out using isolated epididymal adipocytes. The alpha 2-adrenergic agonist UK 14304 (UK) inhibited the stimulated lipolysis more in fed than in fasted euthyroid rats whereas it had no effect in hypothyroid or T3-treated hypothyroid rats. The alpha 2-adrenergic antagonist idazoxan reversed the antilipolytic effect of UK more in fasted than in fed euthyroid rats. The alpha 2-adrenergic antagonist RX 821002 (RX) did so, but at lower concentrations than those of idazoxan. Idazoxan slightly increased the glycerol release in hypothyroid and especially T3-treated hypothyroid rats. RX had practically no effect on the production of glycerol in these animals. The findings suggest that (a) fasting and probably hypothyroidism decrease the alpha 2-adrenergic response in adipocytes from rats, (b) T3 treatment of hypothyroid rats has no effect on the alpha 2 response, and (c) thyroid hormone does not directly modulate the alpha 2-adrenergic response in rat adipocytes.

Pre-clinical study of the epinephrine-cisplatin association for the treatment of intraperitoneal carcinomatosis.

We have previously shown that intraperitoneal (i.p.) epinephrine enhances tumour penetration and anti-cancer activity of i.p.-administered cisplatin in rats with peritoneal carcinomatosis. Here, we show a direct correlation between the i.p. epinephrine concentration and cisplatin accumulation in rat peritoneal tumour nodules up to a concentration of 5 mg/l. This concentration leads to a maximal 3.7-fold increase of tumour platinum content and a maximal vasoconstriction of the peritoneal and tumour superficial microcirculation when registered by a laser doppler probe. Further, epinephrine half-life was 20.8+/-3.6 min in the peritoneal cavity of two laparotomized pigs. In these animals, epinephrine plasma concentration, heart rate and systolic blood pressure were dependent on the intraperitoneal dose of epinephrine, and life-threatening signs were not observed in either animal. In conclusion, a 5 mg/l concentration of epinephrine could be safely maintained in peritoneal fluid by regular replacement. This concentration is sufficient to maintain a constant vasoconstriction of the peritoneal and tumoral microvascular bed, and enhance the slow diffusion of cisplatin into peritoneal tumour nodules in the course of per-operative intraperitoneal chemotherapy.

[Feasability of the dose adjustment of continuous infusion administration over 120 hours of 5-fluorouracil associated with cisplatin]. / Faisabilité de l'adaptation de la posologie du 5-fluorouracile administré en perfusion continue de 120 heures associé au cisplatine.

Therapeutic monitoring of 120 hours continuous 5-fluorouracil associated with cisplatin. For 31 patients treated by continuous 5-fluorouracil with cisplatin, a therapeutic monitoring of 5-fluorouracil is performed, based on the 48 first hours area under the curve (AUC) and the total AUC. The 5-fluorouracile taylorization allows to reduce some toxicity's while preserving an efficiency (objective responses 42%). Many patients are considered with potentially low 5-fluorouracile clearance. Dose reductions of 5-fluorouracile are frequent, reach 50% during the third cure and allow the achievement of targeted AUC. The role of cisplatin in this necessary reduction of dose is unknown.

[Intraperitoneal cisplatin plus epinephrine and surgical debulking for the treatment of advanced peritoneal carcinomatosis in the rat]. / Optimisation du traitement des carcinoses péritonéales évoluées par la réduction tumorale chirurgicale et l'association cisplatine-adrénaline chez le rat.

OBJECTIVE: To evaluate and compare the effects of cytoreductive surgery with intraperitoneal cisplatin and epinephrine on peritoneal carcinomatosis in the rat. MATERIAL AND METHODS: Twenty-day old peritoneal carcinomatosis was obtained after intraperitoneal injection of 1 x 10(6) DHD/K12/PROb cells into BDIX rats. The surgical treatment included electric fulguration of the peritoneal tumors with spleen and omentum removal while intraperitoneal chemotherapy included platinum (3 mg/kg) associated with epinephrine (2 mg/kg). RESULTS: Surgery did not increase rat survival unlike cisplatin or cisplatin/epinephrine chemotherapy. Intraperitoneal chemotherapy alone with cisplatin +/- epinephrine increased survival but did not provide cure. Surgery followed by intraperitoneal cisplatin and epinephrine cured four out of five twenty-day old peritoneal carcinomatosis. CONCLUSION: Surgery combined with intraperitoneal cisplatin and epinephrine could be an efficient treatment for peritoneal carcinomatosis in man.

Epinephrine enhances penetration and anti-cancer activity of local cisplatin on rat sub-cutaneous and peritoneal tumors.

Despite the theoretical advantages of a high local concentration of anti-cancer drugs, local chemotherapy often fails to produce complete and lasting responses in experimental and human solid tumors. Experiments using Patent Blue dye showed that fluids diffused poorly into tumor mass when injected inside or around s.c. rat tumors in rats. In the same way, Patent Blue dye distributed poorly from the peritoneal cavity into the tumor nodules of rats with peritoneal carcinomatosis. The potent vasoconstrictor, epinephrine (1 mg/kg of body weight) was shown to facilitate the penetration of Patent Blue dye into s.c. and peritoneal rat tumors. Platinum concentration evaluated by micro-PIXE in s.c. DHD/K12/ PROb colon tumors or by atomic absorption spectrometry in DHD/K12/PROb peritoneal tumors was 4- to 12-fold higher when epinephrine was added to local cisplatin. Peri-tumoral or intra-tumoral injection of cisplatin (2 mg/kg) alone does not cure s.c. DHD/K12/PROb colon tumors or GV1A1 glioma tumors in BD IX rats. By contrast, a complete and lasting cure of s.c. tumors was achieved regularly and without skin necrosis when epinephrine was added to intra-tumoral or peri-tumoral cisplatin. Rats with peritoneal-tumor nodules 1 to 2 mm in diameter, and insensitive to i.p. cisplatin alone, were cured when the anti-cancer drug was combined with epinephrine. These experimental results could justify clinical trials using a combination of cisplatin and epinephrine in the treatment of locally growing solid tumors.

Increased cytotoxicity and stability of Lipiodol-pirarubicin emulsion compared to classical doxorubicin-Lipiodol: potential advantage for chemoembolization of unresectable hepatocellular carcinoma.

There is no well-defined curative treatment for advanced and unresectable hepatocellular carcinoma. The widely used transarterial chemoembolization (TACE) with a doxorubicin-Lipiodol emulsion has not been shown to improve survival in randomized studies. Further, obstruction of the hepatic artery used in the procedure is badly tolerated in patients with cirrhosis. Drugs with a more rapid penetration into the cancer cells are likely to eliminate the need for obstruction of the hepatic artery. We therefore compared the cytotoxicity of another anthracycline pirarubicin with that of the commonly used doxorubicin. In this report, we show that pirarubicin has a greater in vitro cytotoxic effect than doxorubicin on the HepG2 and Hu-H7 human hepatoma cell lines. Pirarubicin emulsion with Lipiodol is more stable at 37 degrees C than doxorubicin-Lipiodol. Moreover, pirarubicin accumulates at a greater extent in the oil phase, permitting Lipiodol to act as a slow-releasing vector for the anthracycline. Further, amiodarone, a multidrug resistance inhibitor, was shown to decrease the intrinsic resistance of HepG2 and Hu-H7 cells to both anthracyclines, and the presence of polysorbate 80 in the amiodarone preparation increased the stability of the anthracycline-Lipiodol emulsions. We therefore conclude that pirarubicin is a better candidate for TACE than doxorubicin. The rapid and increased cytotoxicity of pirarubicin on hepatoma cancer cells and the stability of the pirarubicin-Lipiodol amiodarone emulsion could avoid the complete obstruction of the hepatic artery by Gelfoam sponges, and provide a better tolerated method of TACE in patients with latent liver insufficiency.

Deleterious effect of serum proteins on the amphotericin B-induced potentiation of cisplatin in human colon cancer cells.

Inherent resistance of colon cancer cells to cis-diamminedichloroplatinum(II) (CDDP) is partly attributed to reduced drug penetration through plasma membrane. Amphotericin B (AmB), a polyene antifungal antibiotic, has been shown to increase CDDP penetration and cytotoxicity on several non-digestive cancer cell lines. We demonstrated here that AmB dramatically increases the penetration of CDDP, and to a lesser extent that of carboplatin (Carbo-P) and oxaloplatin (L-OHP), in the primary resistant HT 29 human colon cancer cells when drug incubation is performed in serum-free medium. The cytotoxicity of CDDP but not that of Carbo-P and L-OHP was increased by AmB. However, AmB-induced potentiation of CDDP penetration and toxicity was almost completely abolished when cell incubation was performed in presence of human serum. We investigated whether the dilution of human serum by a high osmotic power gelatine solution (Lomol) could restore the positive effect of AmB on CDDP accumulation in HT 29 cells. Incubation of cells with CDDP and AmB in pure Lomol resulted in a 6-fold increase in platinum cellular content. However, addition of serum (25%) in Lomol solution reduced to only 2-fold the increase in platinum cellular content provoked by AmB. These disappointing results show that AmB is probably uninteresting as a modulator of CDDP resistance in clinical practice. The use of haemodilution to restore the positive AmB effect on platinum cellular accumulation cannot be warranted.