Selective preconcentration and determination of tributyltin in fresh water by electrothermal atomic absorption spectrometry.

A rapid and simple method for separation and determination of tributyltin (TBT) in mineral and tap water is described. The procedure is based on the selective retention of TBT by a chelating resin, Amberlite XAD-2 impregnated with tropolone. The addition of 0.8% sulfuric acid to the water sample leads to the retention of TBT by the resin while monobutyltin (MBT), dibutyltin (DBT) and inorganic tin remain in solution. TBT is eluted with methyl isobutyl ketone (MIBK) obtaining a preconcentration factor of 80. Tin concentration is determined by ETAAS using zirconium coated tubes. Multi-injection and hot injection techniques are used in order to enhance the sensitivity of the method. A detection limit of 14.4 ng L(-1) is achieved with recoveries near to 100%. The procedure has been successfully applied to TBT determination in various fresh water samples.

Longitudinal study of fatty acids in plasma and erythrocyte phospholipids during pregnancy.

AIM: To assess the modifications of the main fatty acids (FA) in plasma and red blood cells during pregnancy. METHODS: A longitudinal study of 36 normal pregnant women was carried out with 3 cut-off points: first trimester, second trimester and third trimester. 14 FA in plasma and erythrocyte phospholipids were measured using capillary gas chromatography. Measurements were expressed in percentages and in absolute values. RESULTS: In plasma there was a significant increase in the proportion of saturated FA and a decrease in the proportion of long chain polyunsaturated fatty acids (PUFA) both in the omega 6 (omega 6) and omega 3 (omega 3) series. On the other hand, in erythrocyte phospholipids there was a decrease in the proportion of eicosapentaenoic acid and an increase in that of docosahexaenoic acid. In the omega 6 series, dihomo-gamma-linolenic acid increased, whereas the omega 6 docosapentaenoic acid decreased. CONCLUSION: There was a significant decrease in the proportion of omega 3 PUFA in plasma from the first to the third trimester. Thus, it is suggested that the omega 3 PUFA intake during pregnancy should be increased in the last trimester.

P-glycoprotein, HER-2/neu, and mutant p53 expression in human gynecologic tumors.

BACKGROUND: Overexpression of P-glycoprotein has been associated with a worse prognosis for some groups of patients not receiving chemotherapy. Recently, it has been demonstrated that in vitro both c-Ha-Ras overexpression and mutant p53 overexpression do activate the MDR1 gene (also known as PGY1) in murine NIH 3T3 cells. This direct connection between oncogenic activation, antioncogenic malfunctioning (presence of mutant instead of wild-type p53 protein), and MDR1 gene expression constitutes a fundamental conceptual model that could provide an explanation for the obscure prognostic role, in the absence of chemotherapy, of the MDR1 gene. PURPOSE: Our goal was to test whether the relationship between MDR1 (P-glycoprotein) expression, oncogenic activation, and mutant p53 protein expression demonstrated in vitro is also reproducible in vivo for two groups of human gynecologic tumors. METHODS: Fifty tumor specimens (31 mammary, 11 endometrial, and eight cervical) were analyzed. They had been obtained from previously untreated patients. Aliquots of these specimens had been frozen and stored at -70 degrees C since surgical collection or routinely fixed in formalin and embedded in paraffin. DNA was extracted from routinely fixed specimens for single-strand conformation polymorphism (SSCP) analysis. Immunohistochemical techniques were used on frozen material to determine: 1) P-glycoprotein expression using two different monoclonal antibodies (c219 and JSB1); 2) HER-2/neu (c-erb-B2; also known as ERBB2) expression using the NCL-CB11 monoclonal antibody; and 3) mutant p53 protein expression using the PAb 1801 monoclonal antibody. Polymerase chain reaction (PCR)-SSCP was used to confirm recognition of the mutated isoform of p53. Endometrial and cervical carcinomas were studied by both PCR-SSCP DNA analysis and immunohistochemical analysis. Only when there was full concordance between both methods were endometrial and cervical tumors considered to express mutant p53. RESULTS: A statistically significant (P = .009; Fisher's exact test) association between HER-2/neu and MDR1 expression was found for the more aggressive form of inoperable, locally advanced mammary carcinoma. Expression of HER-2/neu or mutant p53 was similar in both tumor groups studied--mammary carcinoma with a low basal expression of P-glycoprotein compared with endometrial and cervical carcinomas with significantly (P = .0002; chi-square test) higher levels of expression. CONCLUSIONS: The highly statistically significant coexpression of P-glycoprotein and HER-2/neu took place only in the subgroup of aggressive, locally advanced, inoperable mammary carcinomas, whereas no statistically significant association could be found for operable tumors. No association between mutant p53 expression and MDR1 activation was found in the human tumors analyzed.

Serum sickness related to current procedures of in vitro fertilization--a case report.

A variety of cutaneous and systemic adverse reactions related to procedures of in vitro fertilization (IVF) have been reported, among them skin reactions secondary to LHRH agonists--attributed to nonspecific histamine release--and a serum sickness-like syndrome which appears to be related to heterologous sera contained in the rinsing solution for graafian follicles. We report here the case of a 41-year-old woman who on two occasions suffered from clinical features consistent with serum sickness after being submitted to current IVF protocols. A specific IgG-mediated reaction against bovine serum albumin (BSA) was demonstrated. The avoidance of BSA or other heterologous sera in the rinsing solutions for graafian follicles is advisable in all IVF protocols, since it adds an unnecessary risk of developing immune complex-related illness.

Variations in estrogen and progesterone receptor levels after short-term tamoxifen treatment in breast carcinoma.

The modification of estrogen and progesterone receptor status was prospectively studied in mammary carcinoma after short-term (7 days) administration of tamoxifen citrate (30 mg/day). Seventeen patients fulfilled the stringent criteria required for final evaluation. Tamoxifen was administered to them immediately prior to surgery and receptor status was studied on the surgical specimen. Estrogen receptor levels were significantly (p < 0.05) decreased after treatment, whereas progesterone receptors remained statistically unaltered, although they showed a tendency towards significant increase (p = 0.12). Following these results, short-term tamoxifen treatment seems inadequate for the induction of significant levels of progesterone receptors in mammary carcinoma.

Pruritic urticarial papules and plaques of pregnancy.

The authors present a rare case of pruritic urticarial papules and plaques of pregnancy in a 25-year-old caucasian primigravida admitted to our department because of pruritus in the third trimester of gestation. Recommendations for management are discussed.