[Resuscitation of the burned child in critical condition]

Recent advances in surgical techniques, control of infection and nutritional support have dramatically increased the survival rates of burned children. The characteristics of severely burned pediatric patients dictate that management be different from that required for adults in the intensive care unit. The formulas for fluid replacement should be based on body surface rather than weight in children and adjusted for degree of stress and age, with appropriate monitoring and treatment of hypothermia, pain and associated psychological disorders. Early assessment and treatment of airway obstruction and gas and smoke inhalation syndromes with high FiO2 is necessary; prophylactic endotracheal intubation may be required.

Modulation of prostaglandin H synthase-2 mRNA expression by 2,3,7,8-tetrachlorodibenzo-p-dioxin in mice

Prostaglandin endoperoxide H synthases (PGHS-1 and PGHS-2) catalyze an intermediate step in the biosynthesis of prostaglandins and thromboxanes. Recently, it was observed that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) modulates the expression of PGHS-2 mRNA in different cell lines. The main aim of this study was to examine whether PGHS-2 mRNA expression can be changed by acute TCDD in vivo and, second, we were also interested in whether modulation of PGHS-2 is mediated by the aryl hydrocarbon receptor (AhR) which is known to be involved in the transcriptional control of TCDD-induced phase 1 and phase 2 enzymes. Initially C57BL/6J mice were treated with a single dose of 10,000 ng TCDD/kg and the PGHS-1 and PGHS-2 mRNAs were analyzed in liver, lung, thymus, kidney, and spleen. In all tissues examined the expression of PGHS-1 mRNA was not affected by TCDD. However, TCDD treatment enhanced the PGHS-2 mRNA levels in lung and spleen. No effect of TCDD on PGHS-2 expression was found in liver and kidney. For dose-response studies C57BL/6J and DBA/2J mice were treated for 24 h with various doses of TCDD (1-50,000 ng/kg) and the PGHS-2 mRNA increases were analyzed in lungs and spleens. A significant increase of PGHS-2 mRNA in lungs of C57BL/6J mice was found at a dose of 100 ng TCDD/kg, whereas a nearly 100-fold higher TCDD dose was needed to increase PGHS-2 in DBA/2J mice. A similar dose-dependent induction of PGHS-2 was found in spleens of C57BL/6J mice; however, no significant increase of PGHS-2 was found in spleens of DBA/2 mice. These results indicate an involvement of AhR in TCDD-mediated changes of PGHS-2 expression. This suggestion is supported by studies in AhR-deficient animals which showed that TCDD had no effect on PGHS-2 mRNA. When changes of PGHS-2 mRNA expression are compared with those of CYP1A1 between 4 and 72 h after TCDD, it is noteworthy that TCDD led to a delayed and more transient increase of PGHS-2. These data suggest that the mechanism of modulation of both genes by TCDD may be different.

Algesics excite axotomised afferent nerve fibres within the first hours following nerve transection in rats

The direct consequences of a peripheral nerve injury at the lesion site itself are often twofold: axons of afferent (and efferent) nerve fibres are transected and the tissue surrounding the nerve injury site is inflamed. Recent studies have shown that a few hours after nerve transection, axotomised myelinated (A) and unmyelinated (C) afferents may respond to mechanical and thermal stimuli applied to the cut nerve end. Here, 5-24 h after sural nerve ligation and transection we studied the ectopic excitability of axotomised cutaneous A and C fibres by chemical agents, most of which excite afferent terminals in skin. Topical application of bradykinin (BK; 10(-4) M) to the nerve stump excited 7.3% of all C fibres tested. Application of prostaglandin E2 (PGE2), a solution with increased proton concentration (pH 6.0) or a combination of inflammatory mediators ('inflammatory soup', containing histamine, 5-HT, BK and PGE2 (all 10(-5) M) at a pH of 7.0) activated 2.7-4.3% of all C fibres tested. Hypertonic saline solution (HS; 4.5%) and capsaicin, painful irritants, excited 8.3% and 5.0% of the C fibres, respectively. Among the axotomised A fibres tested, between 0.8% and 1.7% were excited by BK, PGE2, inflammatory soup (IS) or HS. Capsaicin and acid pH did not excite cut A fibres. In total, the number of chemically excited C fibres (50/547) significantly exceeded the number of activated A fibres (10/469). Local norepinephrine application (0.5-2.4.10(-3) M) did not activate A or C fibres (234 and 224 fibres tested, respectively). The results indicate that already during the first hours after transection of a peripheral skin nerve a significant proportion of axotomised afferents can be excited by topical chemical stimulation. This evoked activity is preferentially found in unmyelinated fibres, many of which have nociceptive functions. Chemically evoked discharges as described in the present study may therefore contribute to the induction of pain and paraesthesias in patients with peripheral nerve lesion when the injury site is inflamed.

Effect of transforming growth factor-beta1 on expression of aryl hydrocarbon receptor and genes of Ah gene battery: clues for independent down-regulation in A549 cells

An inhibitory effect on both constitutive and inducible expression of cytochrome P450 isoenzymes has been shown for different cytokines and growth factors. We previously described an inhibition of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced CYP1A1 mRNA and enzyme activity by transforming growth factor-beta1 (TGF-beta1) in human lung cancer A549 cells. In the present study, we report that not only TCDD-induced expression of CYP1A1 but also basal mRNA expression of CYP1A1, CYP1B1, and aryl hydrocarbon receptor (AHR) was down-regulated by TGF-beta1 in cells not treated with TCDD. In contrast, mRNA expression of the AHR partner protein Arnt (aryl hydrocarbon receptor nuclear translocator) was not influenced. Furthermore, TCDD-induced expression of CYP1B1 and NMO-1 was inhibited, and the IC50 values of 5-10 pM TGF-beta1 were in the same range as observed for inhibition of CYP1A1 and AHR mRNA expression. Transfection studies with a plasmid containing a luciferase reporter gene under control of two dioxin-responsive elements indicate an effect on AHR protein expression. Results of time-course studies revealed a parallel inhibition of AHR and CYP1 mRNA expression, indicating that TGF-beta1 is a direct negative regulator of transcription of these genes. The treatment of cells with cycloheximide led to a superinduction of TCDD-induced CYP1A1 and CYP1B1 mRNA expression and abolished the inhibitory effect of TGF-beta1 on basal as well as TCDD-induced CYP1 and AHR mRNA expression. TGF-beta1 seems not to influence the stability of AHR mRNA. The results suggest that TGF-beta1 induces rapid transcription and translation of an as-yet-unknown negative regulatory factor or factors that may directly regulate expression of AHR and genes of Ah gene battery.

Cardioprotection with dexrazoxane for doxorubicin-containing therapy in advanced breast cancer

PURPOSE

To determine the cardioprotective effect of dexrazoxane (DZR) used in a doxorubicin-based combination therapy in advanced breast cancer.

PATIENTS AND METHODS

Between November 1988 and January 1991, 534 patients with advanced breast cancer were randomized to two multicenter, double-blind studies (088001 and 088006). Patients received fluorouracil, doxorubicin, and cyclophosphamide (FAC) with either DZR (DZR-to-doxorubicin ratio, 10:1) or placebo (PLA) every 3 weeks and were monitored with serial multiplegated acquisition (MUGA) scans.

RESULTS

The hazards ratio (HR) of PLA to DZR for a cardiac event, which was predefined ejection fraction changes or congestive heart failure (CHF), was 2.63 (95% confidence interval [CI], 1.61 to 4.27; P < .001) for 088001 and 2.00 (95% CI, 1.01 to 3.96; P = .038) for 088006. The objective response rates for 088001 were 46.8% for DZR and 60.5% for PLA, a difference of 14% (95% CI, -25% to -2%; P = .019), and for 088006 were 53.7% for DZR and 49.3% for PLA, a difference of 4% (95% CI, -13% to 22%; P = .63). Time to progression and survival were not significantly different between treatment arms in either study. Toxicities on the DZR arms included lower granulocyte and platelet counts at nadir (P = .009 and P = .004, respectively) and more pain on injection (P = .001), with no difference in the rates of fever, infection, or hemorrhage.

CONCLUSION

DZR had a significant cardioprotective effect as measured by noninvasive testing and clinical CHF. One of the two studies (088001) showed a lower response rate with DZR, but time to progression and survival were not significantly different. DZR is the first agent shown to reduce cardiotoxicity from doxorubicin.

Effect of subchronic 2,3,7,8-tetrachlorodibenzo-p-dioxin exposure on immune system and target gene responses in mice: calculation of benchmark doses for CYP1A1 and CYP1A2 related enzyme activities

The dose-effect relationships were analysed for several noncarcinogenic endpoints, such as immunological and biochemical responses at subchronic, low dose exposure of female C57BL/6 mice to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The animals were treated i.p. with TCDD according to the initial- and maintenance-dose principal for a period of 135 days. The initial doses were 1, 10 and 100 ng TCDD/kg, the weekly maintenance doses were 0.2, 2 and 20 ng TCDD/kg, respectively. At days 23, 79 and 135 of TCDD/kg, treatment 10 animals of each dose group were killed. As immunological parameters the number of thymocytes and the pattern of thymocyte subpopulations were determined. In liver, lung and thymus, mRNA expression of TGF-alpha, TGF-beta(1), TGF-beta(2), TGF-beta(3), TNF-alpha, IL-1 beta and different CYP1 isoforms (CYP1A1, CYP1A2, CYP1B1) was analysed. In the livers, activities of 7-ethoxyresorufin-O-deethylase (EROD) and 7-methoxyresorufin-O-demethylase (MROD) were measured. TCDD content in the liver was determined. The main results are summarized as follows: (1) The TCDD doses were not sufficient to elicit dose-dependent changes of pattern of thymocyte subpopulation. (2) TCDD failed to change the mRNA expression of TGF-alpha, TGF-beta and TNF-alpha, but led to an increase of IL-1 beta mRNA expression in liver, lung and thymus. The results show that the TCDD induced IL-1 beta mRNA increase is at least as sensitive a marker as the induction of CYP1A isoforms. (3) The expression of CYP1B1 mRNA remained unchanged at the doses tested, while CYP1A1 and CYP1A2 mRNA expression was dose-dependently enhanced. EROD and MROD activities in the liver paralleled the increases of CYP1A1 and CYP1A2 mRNA expression. (4) Regression analysis of the data showed that most of the parameters tested fit a linear model. (5) From the data, a benchmark dose for EROD/MROD activities in the livers of female C57BL/6 mice of about 0.03 ng TCDD/kg per day was calculated.

Prolonged injury discharge in unmyelinated nerve fibres following transection of the sural nerve in rats

We studied the prolonged injury discharge in axotomized myelinated (A) and unmyelinated (C) nerve fibres within the first 15 min following sural nerve transection of the rat. Immediately after axotomy, 18% (22/122) of the C fibres generated action potentials, but none of 73 A fibres. This discharge ceased during the first 2 min after axotomy in most of the C fibres. The discharge frequency in the first 15 s after nerve cut varied between 0.3 and 7.2 Hz (mean 2 Hz) and decreased to a mean of 0.3 Hz 4 min after nerve lesion. C fibres displaying initial discharge frequencies of > or = 2 Hz ceased to generate action potentials significantly sooner than those with initial discharge frequencies of < 2 Hz.

[Tropisetron for the prevention of nausea and vomiting during chemotherapy: multicenter clinical study]

The antiemetic effect of tropisetron was studied in 97 cancer patients (67 men, 30 women) receiving cisplatin in doses of 75 mg/m2 or higher. On 279 chemotherapy cycles studied (max 6 per patient) 5 mg of tropisetron was administered once a day i.v on day 1 and p.o. on days 2 to 6. Efficacy preventing vomiting and nausea was measured in 24 hour period as: complete control O episodes, major control 1 to 2 episodes, minor control 3 to 4 episodes and no control 5 or more episodes. Satisfactory vomiting control (complete and major) was 69%, 63%, 82%, 88%, 96% and 96% in days 1 to 6 of cycle 1. Satisfactory nausea control (complete and major) for the same days was 70%, 66%, 72%, 85%, 92% and 97%. Similar data was obtained for the subsequent cycles. Complete vomiting control was obtained in 47%, 35%, 56%, 72%, 81% and 84% and for nausea in 42%, 39%, 48%, 64%, 81% and 87%. 19 patients presented adverse effects (19.6%). Only 2 headache episodes had a definite relation with the antiemetic drug. 12 patients discontinued the medication; 6 due to drug inefficacy, 2 to illness unrelated to the drug, 1 to lack of collaboration, and 3 due to other reasons. We conclude that tropisetron allows satisfactory control of acute and delayed vomiting in a high percentage of patients treated with high doses of cisplatin. The drug does not have significant secondary effects. Tropisetron administration in only one daily dose implies an evident advantage and a treatment cost reduction.

Thermosensitivity of acutely axotomized sensory nerve fibers

1. Thermosensitivity of axotomized myelinated and unmyelinated fibers in the sural nerve was examined in anesthetized rats within 24 h after nerve ligation and transection. Activity in single fibers was recorded extracellularly from small filaments dissected from the nerve approximately 20-30 mm proximal to the lesioned site. Cold and warm stimuli were applied to the ligated and cut nerve end or 5-10 mm further proximal. 2. Among 871 unmyelinated fibers tested, 40 were excited by cooling of the cut and ligated nerve end (8-15 degrees C), 44 were excited by warming (35-65 degrees C), and 16 were both cold and warm sensitive. None of the 438 myelinated fibers investigated were activated by either cold or warm stimuli. 3. Cold- and warm-sensitive fibers responded in a graded fashion to thermal stimuli of variable temperatures. Between 11 and 30 degrees C, the responses of cold-sensitive fibers increased when the temperature was reduced. Responses of warm-sensitive fibers increased between 40 and 65 degrees C, when the temperature was increased. 4. Thermosensitive fibers displayed characteristic response profiles. Responses to cold stimuli were maximal at the beginning and decreased continuously to lower discharge frequencies as the stimuli were maintained. The stimulus-response curves to warm stimuli were bell-shaped and discharge frequencies were maximal after 5-15 s. 5. In some cold-sensitive fibers a spatial gradient of excitability emerged after axotomy. Maximal responses to isothermal stimuli were observed at the transection site, whereas the excitability declined when the thermal stimuli were applied 5 and 10 mm further proximal. 6. After axotomy, 190 unmyelinated fibers were exposed to cold and warm stimuli at two sites 5 and 10 mm proximal of the nerve stump, and 172 intact C fibers were stimulated at anatomically comparable sites along the nerve. No statistically significant difference was found between the prevalences of thermosensitivity of C fibers along their axons in these two groups (7 of 172 vs. 11 of 190). 7. In conclusion, some unmyelinated fibers can be ectopically excited by thermal stimuli within 24 h after nerve cut and ligation. This ectopically evoked activity may contribute to the generation of paresthesias, painful sensations, and associated changes following peripheral nerve lesion.

Fadrozole HCL (CGS-16949A) versus megestrol acetate treatment of postmenopausal patients with metastatic breast carcinoma: results of two randomized double blind controlled multiinstitutional trials

BACKGROUND

Breast cancer patients with prior response to endocrine therapy achieve subsequent benefit from additional endocrine therapies. The efficacy and safety of an aromatase inhibitor, fadrozole HCL, were compared with megestrol acetate in post menopausal patients who had disease progression after receiving antiestrogen therapy either for metastatic disease or as adjuvant therapy.

METHODS

In 2 multiinstitutional prospective trials, 683 postmenopausal patients were randomized to receive either fadrozole HCL, 1 mg twice daily, or megestrol acetate, 40 mg 4 times daily, in a double blind fashion after progression on first-line hormonal therapy. Objective response rates, time to progression, survival and safety of the two regimens were compared.

RESULTS

Results of intent-to-treat analyses are presented in this study. No significant differences were detected between the two treatment groups in time to progression, objective response rates, duration of response, and survival in either trial. There were no clinically meaningful differences between the treatment groups in the incidence and severity of adverse experiences, except that weight gain, fluid retention, and dyspnea were observed in more patients in the megestrol acetate group compared with those receiving fadrozole HCL, whereas nausea and vomiting were observed in more patients in the fadrozole HCL group compared with those receiving megestrol acetate.

CONCLUSIONS

Fadrozole HCL was as efficacious as megestrol acetate in postmenopausal patients with metastatic breast carcinoma after one hormonal therapy. Adverse experiences were mild with both therapies, but megestrol acetate was associated wiht a higher frequency of weight gain, fluid retention and dyspnea, whereas fadrozole HCL was associated with a higher frequency of nausea and vomiting.

Dose-response relationship of cytochrome P4501b1 mRNA induction by 2,3,7,8-tetrachlorodibenzo-p-dioxin in livers of C57BL/6J and DBA/2J mice

The dose-response relationship of cytochrome P4501b1 (Cyp1b1) and Cyp1a1 induction in livers of TCDD-treated female C57BL/6J and DBA/2J mice are described. The animals were treated i.p. with 0.001, 0.01, 0.1, 1, 10 and 50 micrograms TCDD/kg for 24 h, and Cyp1b1 and Cyp1a1 mRNA expression was analyzed by RT-PCR. In the livers of both mouse strains, the Cyp1b1 and Cyp1a1 mRNA content was increased after TCDD exposure in a dose-dependent manner. These effects were more pronounced in TCDD-responsive C57BL/6J mice than in the less responsive DBA/2J mice, although Cyp1a1 was more responsive to TCDD than Cyp1b1 in both strains. The calculated ED50 values for Cyp1b1 and Cyp1a1 induction in livers of TCDD-treated C57BL/6J mice were 1.3 and 0.08 micrograms TCDD/kg, respectively. The corresponding values for half-maximal induction response in livers of DBA/2J mice were 3.4 micrograms TCDD/kg for Cyp1b1 and 1.5 micrograms TCDD/kg for Cyp1a1. These results show that Cyp1b1 mRNA expression is less inducible by TCDD than Cyp1a1. Both genes are highly inducible in TCDD-responsive C57BL/6J mice expressing the high affinity arylhydrocarbon receptor (Ah receptor), suggesting that Cyp1b1, like Cyp1a1, is a potential Ah receptor-regulated gene.

[Amniotic fluid embolism: review]

The amniotic fluid embolism, is a very uncommon syndrome but because of its severity and high mortality, it is interesting to study and to get a deep knowledge of its etiopathogenia and physiopathology. In this article, we revise the actually purposed pathogenic mechanisms, specially the humoral mechanisms in front of mechanical, as it was defended a few years ago. The diagnostic of this syndrome, is an interesting question, because it is not only pathology, actually it trends to immunologic diagnosis. The amniotic fluid embolism, interests to anesthesiologist and its differences in cardiopulmonary resuscitation in the pregnant woman too. All these data are discussed in our article, as much as treatment, that is based upon haemodinamics and cardiopulmonary resuscitation.

Intravenous vinorelbine as first-line and second-line therapy in advanced breast cancer

PURPOSE

We evaluated single-agent intravenous (IV) vinorelbine as first- and second-line treatment for advanced breast cancer (ABC) in patients who were not resistant to anthracyclines. Objective tumor response (TR) and toxicity were assessed.

PATIENTS AND METHODS

A total of 107 women were enrolled onto this multicenter, nonrandomized, open-label phase II study. Patients were stratified into first- and second-line treatment groups, based on prior treatment history. Vinorelbine was initially given at 30 mg/m2/wk, with dose modification for toxicity as indicated. Therapy was continued until disease progression or severe toxicity mandated withdrawal or until the patient asked to be removed from the study.

RESULTS

The objective response rate for all patients was 34% (95% confidence interval [CI], 25% to 44%): 35% (95% CI, 23% to 48%) for first-line patients and 32% (95% CI, 20% to 47%) for second-line patients. Nine first-line and three second-line patients obtained a complete response (CR). The median duration of objective response was 34 weeks in both groups. The overall survival durations of first- and second-line patients were 67 weeks and 62 weeks, respectively. Granulocytopenia was the predominant dose-limiting toxicity. Two patients died on study as a result of granulocytopenic sepsis.

CONCLUSION

Single-agent vinorelbine is an effective and well-tolerated agent for first- and second-line therapy of ABC. The results of this study confirm the findings of similar international trials and suggest vinorelbine should be considered a valid treatment option for patients with ABC and a potential component in future combination regimens for this disease.

Randomized comparison of vinorelbine and melphalan in anthracycline-refractory advanced breast cancer

PURPOSE

This prospective multicenter randomized trial was performed to compare the effectiveness and safety of intravenous (i.v.) vinorelbine tartrate (Navelbine [NVB]; Burroughs Wellcome Co, Research Triangle Park, NC) with i.v. melphalan (Alkeran [ALK]; Burroughs Wellcome Co) in a heavily pretreated population of patients with anthracycline-refractory advanced breast cancer (ABC). Efficacy end points included time to disease progression (TDP), time to treatment failure (TTF), survival, tumor response rates, and quality of life (QL) and relief of cancer-related symptoms.

PATIENTS AND METHODS

Between August 24, 1990, and December 1, 1992, 183 patients were randomized (2:1) to treatment with NVB (30 mg/m2 weekly) or ALK (25 mg/m2 every 4 weeks) i.v. Patients were stratified by measurable or nonmeasurable-assessable disease and by treatment center.

RESULTS

Time to disease progression was significantly longer with NVB than with ALK, with a median 12 weeks versus 8 weeks, respectively (P < .001). NVB patients also had significantly longer time to treatment failure than ALK patients, with a median 12 weeks versus 8 weeks, respectively (P < .001). The effect of NVB on survival was also statistically significant (P = .034): 1-year survival rates were 35.7% with NVB and 21.7% with ALK and the median survival rate was 35 weeks and 31 weeks, respectively. In total, 46.5% of NVB patients and 28.2% of ALK patients achieved an objective response or stabilization of disease (P = .06). No intergroup differences were noted in patient-assessed QL and cancer-related symptoms. The most common toxicities were hematologic, including granulocytopenia with NVB and thrombocytopenia and granulocytopenia with ALK. Both drugs were generally well tolerated, and no septic deaths were reported.

CONCLUSION

This randomized trial demonstrates a survival benefit in anthracycline-refractory ABC. NVB was well tolerated and demonstrated activity superior to ALK in anthracycline-refractory ABC, without compromising QL. Based on activity of single-agent NVB in this difficult-to-treat patient population, investigations of NVB in combination with other anticancer drugs are warranted.

Development of spontaneous activity and mechanosensitivity in axotomized afferent nerve fibers during the first hours after nerve transection in rats

1. Spontaneous activity and ectopic mechanical excitability of axotomized unmyelinated and myelinated fibers in the sural nerve were examined in anesthetized rats. The analysis was performed within 30 h after the nerve lesion using single-fiber recordings that were performed proximal to the severed nerve end. 2. Among all unmyelinated fibers tested (n = 865), 4-8% exhibited persistent spontaneous activity of low and irregular frequency. The percentage of spontaneously active C fibers did not change significantly during the first 30 h. Only 6 of 796 A fibers had spontaneous activity. 3. Mechanical stimulation of the cut nerve end excited 5-8% of all C fibers under investigation. No development with time could be detected in the frequency of mechanically excitable C fibers. In contrast, beginning 6 h after nerve transection, the number of mechanically excitable A fibers rose with time, reaching 27% after 22-30 h. 4. Among the A fibers (C fibers) that exhibited mechanical excitability or spontaneous activity, only 4% (25%) had both properties, whereas 96% (75%) were either mechanosensitive or spontaneously active. 5. With time after the nerve lesion, the mean discharge rate of all spontaneously discharging C fibers decreased significantly from 49 imp/min (0.5-9 h after nerve lesion) to 11 imp/min after 22-30 h. The mean discharge rate of C fibers exhibiting solely spontaneous activity and those C fibers that were additionally mechanosensitive did not differ significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Different response of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-sensitive genes in human breast cancer MCF-7 and MDA-MB 231 cells

Human breast cancer cell lines are widely used to study the antiestrogenic effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in vitro. Like other groups we found that 10 nM TCDD inhibits cell growth and induces cytochrome P450 1A1 (CYP1A1)-associated 7-ethoxyresorufin-O-deethylase (EROD) activity in MCF-7 cells expressing the estradiol receptor (ER). Neither cell growth nor EROD activity was affected in ER-negative MDA-MB 231 cells. Results of reverse transcription-polymerase chain reaction (RT-PCR) revealed a strong induction of CYP1A1 mRNA in MCF-7 but only a weak increase in MDA-MB 231 cells treated with 1, 10, or 100 nM TCDD. Transcripts of CYP1B1 were detected in both cell lines and mRNA content was enhanced 8- and 30-fold in MCF-7 and MDA-MB 231 cells treated with 1 nM TCDD, respectively. In gel mobility shift assay a stronger signal of DNA-binding aryl hydrocarbon receptor (AhR) was observed in MDA-MB 231 than in MCF-7 cells treated with 10 nM TCDD. These results were confirmed by RT-PCR analyses which showed an approximately 40-fold higher AhR mRNA content in untreated MDA-MB 231 than in MCF-7 cells. In contrast the mRNA of the AhR nuclear translocator was expressed in a similar range of magnitude. Treatment of the cells with TCDD did not change mRNA expression of both genes. Analysis of NADPH:quinone oxidoreductase (NMO-1) and plasminogen activator inhibitor-2 (PAI-2) mRNA expression revealed a dose-dependent induction of both genes in MDA-MB 231 cells after TCDD-treatment. From the results it was concluded that AhR-mediated transactivation is not impaired in ER-negative MDA-MB 231 cells. In addition, the results confirm reported data that expression of ER seems to be important for regulation of CYP1A1 induction after TCDD in human breast cancer cell lines but the present data show that ER does not appear to have a function in TCDD-induced mRNA expression of CYP1B1, NMO-1, and PAI-2 in MDA-MB 231 cells.

Myonecrosis due to Clostridium septicum in a patient with unexplained neutropenia: successful treatment with granulocyte colony-stimulating factor

We report a case of sepsis due to Clostridium septicum successfully treated with granulocyte colony-stimulating factor (GCSF). This case prompted our review of clostridial sepsis and considerations regarding the use of GCSF in cases of drug-induced neutropenia.

Effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin on growth factor expression in the human breast cancer cell line MCF-7

The aim of this study was to examine whether changes in growth factor or cytokine expression could be responsible for the growth inhibitory effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the human breast cancer MCF-7 cell line. Treatment of MCF-7 cells with 10 nM TCDD for 7 days reduced the cell growth to 60% of control; this effect was partly abolished by cotreatment of the cells with 100 nM 17 beta-estradiol (E2). The inhibition of cell growth by TCDD was accompanied by an enhanced secretion of transforming growth factor-beta (TGF-beta) and the TGF-beta content in cell culture supernatants was 2-fold higher than in controls. Using reverse transcription polymerase chain reaction (RT-PCR), the effect of TCDD on the expression of TGF-beta isoforms, transforming growth factor-alpha (TGF-alpha), tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) was investigated. It was demonstrated that incubation with 1, 10 and 100 nM TCDD for 24 h increased mRNA levels of TGF-alpha, TNF-alpha and IL-1 beta. The strongest effect was found on IL-1 beta, the mRNA level of which was dose-dependently increased. TCDD had a minor effect on TGF-alpha and TNF-alpha mRNA. The mRNA levels were significantly increased after treatment with 10 and 100 nM TCDD. The mRNA expression of TGF-beta 1 and TGF-beta 2 was unchanged, whereas the TGF-beta 3 mRNA level was enhanced 2 to 3-fold after TCDD treatment. From the results, we suggest that TCDD-induced growth inhibition in MCF-7 cells is related to the growth inhibitory action of a set of growth factors and cytokines which have a contextual action on MCF-7 cell proliferation.

Alcohol intoxication in young children

This article presents two cases of severe ethyl alcohol intoxication in pediatric patients, with one of these cases resulting in the death of a child. A review of the current literature is provided along with a comparison of our regional poison control centers and the national intoxication statistics regarding pediatric alcohol ingestion. Medical evaluation is recommended for all symptomatic children; hourly observations x 6 h are recommended for asymptomatic children.

Transforming growth factor-beta 1 inhibits TCDD-induced cytochrome P450IA1 expression in human lung cancer A549 cells

The effect of transforming growth factor-beta 1 (TGF-beta 1) on the expression of cytochrome P450IA1 (CYPIA1) was examined in 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-treated human lung cancer A549 cells. Using the reverse transcription-polymerase chain reaction (RT-PCR) it was demonstrated that TGF-beta 1 inhibits CYPIA1 expression in a dose dependent manner. Based on the inhibitory concentration 50 (IC50) of about 5 pM it is suggested that TGF-beta 1 has a physiological function in downregulation of this cytochrome. In the presence of cycloheximide, the effect of TGF-beta 1 on CYPIA1 mRNA disappeared. This finding indicates that protein synthesis may be required for the TGF-beta 1 mediated response of CYPIA1. The possible mechanisms by which TGF-beta 1 interacts with TCDD-responsive drug metabolizing enzymes are discussed.