Pneumonectomy in isoflurane-anesthetized rats without tracheal intubation: an experimental model.

INTRODUCTION: A few models for pneumonectomy in rats have been described, and in most of these, anesthesia includes orotracheal intubation, which increases morbidity and mortality and also adds technical complexity. Models without tracheal intubation but with injectable anesthesia are difficult to reproduce, however, and lead to a lengthy postoperative-recovery period with high morbidity and mortality rates. OBJECTIVE: The objective of this study was to describe a simple, safe, and effective experimental model for pneumonectomy in rats without tracheal intubation. MATERIALS AND METHODS: A left-sided pneumonectomy was performed on 26 Sprague-Dawley rats anesthetized by isoflurane applied via a mask without tracheal intubation. To avoid dangerous traction movements, the lung pedicle was ligated en bloc using clips. RESULTS AND DISCUSSION: No rat demonstrated cardiorespiratory depression. Of the 26 rats, 1 was dehydrated and had lost more than 10% of its body weight, resulting in death on the third day after surgery. Total mortality was therefore 3.8%. Mean (standard deviation [SD]) anesthesia duration was 9.8 (1.0) minutes, surgery time was 3.0 (0.6) minutes, and open pneumothorax time was 1.2 (0.3) minutes. Mean (SD) weight loss during the early postoperative period was 4.5% (3.5%). These results were more satisfactory than results obtained using ketamine mixtures as anesthetic agents (ketamine plus xylacine, and ketamine plus diazepam). CONCLUSION: Our model for left-sided pneumonectomy in isoflurane-anesthetized rats does not require endotracheal intubation and is effective, safe, quick, and easily reproducible.

Kinetics of the in vivo interconversion of the carboxylate and lactone forms of irinotecan (CPT-11) and of its metabolite SN-38 in patients.

The kinetics of the in vivo interconversion of the carboxylate and lactone forms of the prodrug irinotecan, 7-ethyl-10-[4-(1-piperidino)-1- piperidino]carbonyloxycamptothecin (CPT-11), and its active metabolite SN-38 were studied in five patients using a HPLC method that allows the simultaneous determination of all four compounds and detects any hydrolysis of lactones due to inadequate sample handling and storage. The apparent conversion of CPT-11 lactone to the carboxylate in vivo was rapid with a mean half-life of 9.5 min; the carboxylate became the predominant form of plasma CPT-11 soon after the end of the infusion. The ratio of the area under the plasma concentration-time curves of the lactone to total CPT-11 was 36.8 +/- 3.5% (SD). In contrast, SN-38 was present predominantly as the lactone at all times and with little interpatient variability (lactone/total area under the plasma concentration-time curve ratio, 64.0 +/- 3.4%). This may explain in part the promising activity of CPT-11 because CPT derivatives are active against their target, topoisomerase I, only in their lactone form.

Phase I and pharmacokinetic study of the camptothecin derivative irinotecan, administered on a weekly schedule in cancer patients.

Irinotecan (CPT-11) is a novel water-soluble, semisynthetic derivative of camptothecin, with inhibitory effects on mammalian DNA topoisomerase I, high cytotoxic activity in vitro and anticancer activity in animal models. Fifty-nine patients, with cancer refractory to conventional therapy, were entered in this phase I study, using a weekly schedule administration. A total of 304 weekly doses were administered at dose levels ranging from 50 to 145 mg/m2 (30-90 min i.v. infusion). Leukoneutropenia and diarrhea were the dose-limiting toxicities and appeared to be dose related, reversible and noncumulative. However, interpatient variability of toxic effects was substantial. Prolongation of the infusion time from 30 min to 90 min appeared to decrease the diarrhea. Other toxicities included moderate emesis, asthenia, alopecia, abdominal pain, and anemia. CPT-11 plasma disposition was bi- or triphasic with a terminal half-life of 9.3 h. CPT-11 area under the plasma concentration versus time curves increased linearly with dose (r = 0.47, P < 0.01). The active metabolite area under the plasma concentration versus time curve correlated significantly with that of CPT-11, but not with that of CPT-11 dose. Both CPT-11 and 7-ethyl-10-hydroxycamptothecin areas under the plasma concentration versus time curve correlated significantly with leukoneutropenia and diarrhea. One partial and 4 minor responses were observed at dose levels of 130 and 145 mg/m2. Using this weekly schedule, recommended doses for phase II studies are 100 mg/m2 in high risk patients and 115 mg/m2 in others.

Therapeutic efficacy of the topoisomerase I inhibitor 7-ethyl-10-(4-[1-piperidino]-1-piperidino)-carbonyloxy-camptothecin against human tumor xenografts: lack of cross-resistance in vivo in tumors with acquired resistance to the topoisomerase I inhibitor 9-dimethylaminomethyl-10-hydroxycamptothecin.

The efficacy of the topoisomerase I inhibitor CPT-11 [7-ethyl-10-(4-[1-piperidino]-1-piperidino)-carbonyloxycamptothec in] has been evaluated against a panel of human tumor xenografts derived from adult and pediatric malignancies. Tumors included eight colon adenocarcinomas representing intrinsically chemorefractory malignancies, six lines derived from childhood rhabdomyosarcoma (three embryonal and three alveolar) representing a chemoresponsive histiotype, and sublines of rhabdomyosarcomas selected in vivo for resistance to vincristine, melphalan, and the topoisomerase I inhibitor 9-dimethylaminomethyl-10-hydroxycamptothecin (topotecan). CPT-11 was given by i.v. administration daily for 5 days each week for 2 weeks (one cycle of therapy) or on the same schedule with cycles repeated every 21 days. The maximum tolerated dose for a single cycle of treatment was 40 mg/kg/dose, and for 3 cycles the maximum tolerated dose was 10 mg/kg/dose. Treatment was started against advanced tumors. Against colon adenocarcinomas CPT-11 administered for one cycle at the maximum tolerated dose caused complete or partial regression (> or = 50% reduction in tumor volume) in 5 of 8 lines. One cycle of CPT-11 therapy caused significant inhibition of tumor growth, without 50% regression, in 2 of 3 other colon adenocarcinomas. Rhabdomyosarcoma xenografts derived from untreated patients were highly responsive to CPT-11, which caused complete regression in 5 of 6 lines even at 20 or 10 mg/kg/dose. CPT-11 retained complete activity against rhabdomyosarcomas selected for resistance to vincristine and caused complete regressions in a line selected for resistance to melphalan that was also completely cross-resistant to topotecan. Of note was the observation that CPT-11 was as active against two xenografts selected for primary resistance to topotecan as it was against the respective parental tumors. Preliminary data indicate that CPT-11, like the topoisomerase I inhibitor topotecan, may have increased therapeutic efficacy when administered at a low dose for protracted periods (3 cycles). A comparison of the efficacy of CPT-11 with topotecan is presented.

Pharmacokinetics and pharmacodynamics of irinotecan during a phase II clinical trial in colorectal cancer. Pharmacology and Molecular Mechanisms Group of the European Organization for Research and Treatment of Cancer.

PURPOSE: A pharmacokinetic study was performed during a phase II clinical trial of irinotecan (CPT-11) to confirm the pharmacokinetic profile of this drug and its metabolite and to investigate interpatient and intrapatient pharmacokinetic variations and pharmacokinetic-pharmacodynamic relationships. PATIENTS AND METHODS: Twenty-six men and 21 women (mean age, 61 years) with metastatic colorectal cancer, performance status less than 3 (World Health Organization [WHO] scale), and normal renal and hepatic function were administered CPT-11 (350 mg/m2) by 30-minute intravenous (IV) infusion every 21 days. CPT-11 and its metabolites SN-38 and SN-38 glucuronide (SN-38G) were determined by high-performance liquid chromatography (HPLC) using fluorimetric detection. RESULTS: The mean CPT-11 clearance and area under the concentration-time curve (AUC) were 15.2 L/h. m2 and 24,769ng. h/mL, respectively. The large difference in SN-38 and SN-38G AUCs (559 v 2,283 ng. h/mL) was suggestive of extensive glucuronidation of SN-38. Interindividual variation in the metabolic ratio ([AUCSN-38 + AUCSN-38Gl/AUCCPT-11) was marked (coefficient of variation [CV] = 51.6%] compared with intrapatient variation in this variable (CV = 32.6%). A significant relationship existed between percentage reduction in neutrophil count and the AUC of CPT-11 (r = .597, P < .001) and SN-38 (r = .559, P < .001). No relationship was identified between any pharmacokinetic parameter and delayed diarrhea or therapeutic outcome. CONCLUSION: Interindividual variations in the metabolic ratio suggest interpatient variation in carboxylesterase activity. Furthermore, glucuronidation of SN-38 may also be in part responsible for the large interpatient variability in the total SN-38 AUC. Conversely, low intrapatient variation of this parameter was observed in this study, which indicates a lack of autoinduction of the carboxylesterase system. The relationship between neutropenia and both CPT-11 and SN-38 pharmacokinetic parameters confirms the results of previous studies.

Results of a European Organization for Research and Treatment of Cancer/Early Clinical Studies Group phase II trial of first-line irinotecan in patients with advanced or recurrent squamous cell carcinoma of the cervix.

PURPOSE: To determine the efficacy and tolerability of irinotecan (CPT-11) in advanced or recurrent cervical carcinoma. PATIENTS AND METHODS: Eligible patients had histologically confirmed, inoperable, progressive, metastatic or recurrent squamous cell cervical carcinoma and had received no radiotherapy in the preceding 3 months and had never received chemotherapy. The initial irinotecan dosage of 350 mg/m(2) every 3 weeks was modifiable according to toxicity. Treatment continued for six cycles after complete response, or until disease progression or excessive toxicity after partial response, or for three additional cycles in the case of stable disease. Patients were stratified into group A (>/= one measurable lesion in a previously unirradiated area, with or without progressive disease in irradiated fields) or group B (measurable new lesion[s] in an irradiated field). RESULTS: Fifty-one of 55 enrolled patients were eligible for inclusion (median age, 47 years; range, 30 to 71 years). The response rate was 15.7% (95% confidence interval [CI], 7.0% to 28.6%) overall, 23.5% (95% CI, 10.7% to 41.2%) for group A (complete response, 2.9%), and zero for group B. The median time to progression and median survival were 4.0 and 8.2 months for group A and 2.5 and 4.2 months for group B, respectively. The major grade 3/4 toxicities for groups A and B were diarrhea (24.3% and 55.5%, respectively) and neutropenia (24.3% and 33.3%, respectively). There were four toxicity-related deaths, three in group B. Patients with no prior external pelvic irradiation experienced fewer grade 3 and 4 adverse events. CONCLUSION: Irinotecan is effective in treating cervical squamous cell carcinoma if disease is located in an unirradiated area. Because of toxicity, a reduced dose is advised for patients previously treated with external pelvic irradiation.

17 beta-Hydroxysteroid dehydrogenase activity in human breast epithelial cell and fibroblast cultures.

Primary cultures of human breast cells prepared from surgical specimens of reduction mammoplasty were used to study the activity of the enzyme 17 beta-hydroxysteroid dehydrogenase (E2DH) which converts estradiol (E2) into its less active metabolite estrone. This study was performed in both epithelial and stromal cells separated, after collagenase digestion of the tissue, on a Percoll gradient, and then cultured as monolayers in Ham's F 10 medium supplemented differently for epithelial cells and fibroblasts. E2DH activity was strikingly higher in epithelial cells than in fibroblasts, since after [3H]E2 incubation (2 nM), 600 fmol/micrograms DNA were metabolized to estrone in epithelial cells after 1 h, whereas an equivalent amount was hardly obtained in fibroblast cultures after 24 h. The affinity and capacity of E2DH were greater in epithelial cells with apparent Michaelis-Menten constant (Km) = 0.6 +/- 0.1 microM and maximum velocity (Vmax) = 250 to 360 pmol/micrograms DNA/h, whereas they were 10 +/- 1 microM and 50 to 70 pmol/micrograms DNA/h, respectively, in fibroblast cultures. Moreover, the E2DH activity was 2 to 5 times higher in epithelial cells cultured in the presence of the progestin medroxyprogesterone acetate, whereas it remained unchanged in fibroblasts cultured under the same conditions. This increase in E2DH activity was dose dependent from 10(-10) to 10(-7) M medroxyprogesterone acetate and inhibited by both actinomycin D and cycloheximide. This system of differential breast cell culture appears to be a fruitful tool for the study of the hormone dependence of normal breast growth and differentiation. Due to the presence of E2DH, epithelial cells are more apt to undergo and to moderate E2 action. Moreover, epithelial cells are a possible site of progesterone modulation of E2DH activity. Therefore, E2DH could be a good marker both for epithelial cells and their hormone dependence.

General cystic fibrosis mutations are usually missense mutations affecting two specific protein domains and associated with a specific RFLP marker haplotype.

Some 250 different mutations have so far been screened in the cystic fibrosis (CF) gene. The 50 nonsense, 33 splicing and 60 frameshift mutations are randomly distributed within the gene, unlike the 107 missense mutations or amino acid deletions. A large excess of missense mutations affects the exons encoding the first transmembrane (MS1) and first ATP-binding fold (NBF1) domains. Sixty-four of the 107 missense mutations may be classified as private, demic, local and general mutations on the basis of their geographic distribution in Europe. Private and demic mutations are randomly distributed within the gene; local and general mutations are not. It is well known that some RFLP markers are in linkage disequilibrium with some mutations. Private, demic and local mutations are randomly associated with each class of RFLP haplotypes. In contrast, general mutations, frequent and infrequent, are not randomly associated with RFLP markers. General mutations usually affect a specific part of the gene and are more likely to be associated with a specific RFLP marker. This suggests the existence of selective factors favoring these mutations, a hypothesis formerly postulated as a possible cause of the high frequency of the disease.

Demonstration of human kidney differentiation antigens with monoclonal antibodies.

Six human differentiation antigens (EE24.6, EG9.11, EG14.1, EI16.1, EK8.1, EK17.1) have been defined using monoclonal antibodies obtained from mice immunized with embryonic kidney cells. Their histologic distribution was determined on frozen sections of embryonic, fetal, and adult human kidneys by immunofluorescence assay. EE24.6, an ureteral bud marker, was detected only on the germ layer of mature kidney urothelium. EG9.11 and EG14.1 were detected on the S-shaped bodies and also on the adult proximal convoluted tubule for the former and the glomerular basement membrane for the latter. EI16.1, a marker of condensed mesenchyme, was detected only on epithelial cells of adult proximal convoluted tubule. EK8.1 was found in the mesangium, connective tissue, and with particularly dense labeling in the basement membranes. This labeling pattern was present throughout renal organogenesis. EK17.1 recognized both cell and plasma human fibronectins. Staining for all antibodies was nearly identical in mesonephros and metanephros. These results demonstate that some antigens follow their embryonic destiny. They indicate an antigenic similarity between the mesonephros and the metanephros and, therefore, a very early appearance of these antigens. During differentiation, these antigens concentrate on more defined structures, and staining became increased with an increased degree of differentiation.

Direct DNA analysis of fragile X syndrome in Spanish pedigrees.

Eleven complete Spanish pedigrees with fragile X syndrome were analysed by Southern blotting with the DNA probe StB12.3 previously isolated and described by Oberlé et al. [1991]. This probe allowed the direct detection of affected males and carrier females and was able to distinguish between normal males and normal transmitting males (NTMs). One hundred and twenty three individuals were analyzed, 115 from the pedigrees and 8 from the general population. Five mosaic cases were found (4 males and one female) showing both the premutation and the full mutation. One half of the females with the full mutation were mentally retarded but no female with mental retardation carried the premutated pattern, suggesting that the absence of the full mutation in females is a very good criterion for pre-or postnatal diagnosis of normal mental status.

Human triploidy: association with partial hydatidiform moles and nonmolar conceptuses.

A retrospective pathologic review of nearly 100 spontaneous abortions of cytogenetically verified triploid constitution revealed a majority (86 per cent) falling within the category of partial hydatidiform mole, the chief criteria being focal syncytiotrophoblastic hyperplasia, focal villous edema leading to cistern formation, scalloped outline of villi, and frequent "trophoblastic inclusion" formation. The minority (14 per cent) of the conceptuses were nonmolar with a normal or hypoplastic trophoblast. The triploid fetuses in both groups tended to die at about eight weeks' menstrual age. Intrauterine retention was generally prolonged in the partial moles, whereas nonmolar conceptuses tended to abort within the first trimester, often with live or recently dead fetuses. The problem of two distinct morphologic entities within triploidy remains to be further investigated, especially with respect to the etiologic factors responsible for the division.

Pharmacokinetics of irinotecan and its metabolites in human blood, bile, and urine.

Two patients were treated with CPT-11 for colorectal cancer and had a percutaneous biliary catheter for extrahepatic biliary obstruction. The first patient was treated with CPT-11 according to the 100-mg/m2 weekly therapeutic schedule, and the second patient was treated every 3 weeks, with a dose of 350 mg/m2 being given at the first course, after which it was decreased to 300 mg/m2 for the following courses. In plasma, the active identified metabolite of CPT-11, SN-38, occurred mainly in the form of a glucuronide conjugate. CPT-11 was mainly excreted in bile and urine as CPT-11. The cumulative biliary and urinary excretion of CPT-11 and its metabolites (SN-38 and SN-38 glucuronide conjugate) over a period of up to 48 h ranged from 25% (100 mg/m2 weekly) to 50% (300 mg/m2 every 3 weeks). This means that CPT-11 can be excreted under other, not yet identified metabolite forms.

Genetic counselling and prenatal diagnosis for chromosome anomalies. Use of study of spontaneous abortions.

Genetic counselling for chromosome abnormalities must take into account the fact that such anomalies may develop as an error in oogenesis or spermatogenesis or may be transmitted from parents. Since many chromosomally abnormal embryos are spontaneously aborted, parents with repeated unfavorable outcomes of pregnancy or difficulty in conceiving should be studied by karyotype. The relationship between chromosomal abnormalities and various environmental or biologic factors are discussed. The outcome of a previous pregnancy may indicate the necessity of subsequent fetal evaluation even with chromosomally normal parents.

Evaluation of screening methods for Down's syndrome using bootstrap comparison of ROC curves.

This paper concerns the prediction of fetal Down's syndrome in pregnant women. Down's syndrome is the most common congenital cause of severe mental retardation. We elaborate two predictive functions of trisomy 21, combining maternal age and a maternal serum marker. We evaluated them by means of receiver operating characteristic (ROC) curves which give a representation of sensitivity and specificity of a prediction model when varying the cutoff of the predictor on the whole spectrum. Since normal statistical methods for comparison of ROC curves rely on distributional assumptions which were not verified, we used bootstrapping of ROC curves as a check for the statistical significance of differences between the areas under the curves.

[Cost-benefit analysis of prenatal screening for trisomy 21 through analysis of HCG in maternal blood]. / Analyse coût-bénéfice du dépistage prénatal de la trisomie 21 par dosage de l'hCG sérique maternelle.

Introduction of maternal serum markers for prenatal screening of Down's syndrome implies a redefinition of the criteria used for identifying at risk women for screening by amniocentesis, which are currently based on maternal age. On the basis of the first French prospective study of human chorionic gonadotropin measurement in maternal serum as a predictor of Down's syndrome, this paper shows that a screening policy combining maternal age with hCG measurement was more cost-effective than one relying on maternal age alone. A cost-benefit analysis (using the "avoided" lifelong costs of care for a trisomic 21 child that are allowed by prenatal screening) would justify lower hCG cut-off values and an higher detection rate of Down's syndrome (74.5%) than other decision rules based on alternative principles such as: equalization to 1% of fetal risk of Down's syndrome for access to amniocentesis at all maternal ages or equalization to 1/1000 of fetal risk of Down's syndrome among women not undergoing amniocentesis. However, results of the cost-benefit analysis are very sensitive to other factors such as the cost associated with loss of a normal fetus due to iatrogenic risk of amniocentesis (false positives of hCG). Ethical and value-laden issues that necessarily underlie economic evaluation of screening programmes, as well as other decision rules based on equalization of acceptable risk for each maternal age, are discussed.

[Genetic of the 21 hydroxylase deficiency]. / Génétique du déficit en 21-hydroxylase.

A dose genetic linkage exist between the HLA complex (especially HLA-B), and the 21 hydroxylase deficiency form of adrenal hyperplasia. By their polymorphisms HLA antigens can be used as "markers" to follow the segregation of 21-OH deficiency in families, to diagnose the heterozygous offspring and eventually to offer a prenatal diagnosis to couples at risk. In late onset forms of 21-OH deficiency the same genetic linkage has been demonstrated with a high frequency of HLA-B14 antigen.

[Cost effectiveness analysis of prenatal screening of trisomy 21 by maternal serum markers (hCG)]. / Analyse coût-efficacité du dépistage prénatal de la trisomie 21 par marqueur sérique maternel (le cas de l'hCG).

Introduction of maternal serum markers for prenatal screening of Down's syndrome leads to a redefinition of the criteria used for identifying at risk women (i.e. in France, mainly based on maternal age of 38 and over). Effectiveness and costs of prenatal screening of Down's syndrome using such maternal serum markers will vary depending on the biological cut-off values defined, at each maternal age, to identify the population of pregnant women that will be sent to amniocentesis. On the basis of the first French prospective study of the use of human chorionic gonadotropin (hCG) measurement in maternal serum as a predictor of an increased risk of Down's syndrome, this paper shows that a screening policy combining maternal age with hCG measurement is more cost-effective than screening on the basis of maternal age alone. However, final decisions about hCG cut-off values should take into account the complex ethical dilemmas involved, especially the potential consequences of "false positives" and "false negatives", of this marker.

[Grippe and pregnancy. Relation of birth weight to placenta weight]. / Grippe et grossesse. Relation avec le poids de naissance et le poids du placenta.

The different results that have been published concerning the problem of the final outcome for patients who have had influenza during pregnancy reported in numerous works might be explained by differences in methodology used by the different authors. A study was carried out in the Haguenau Maternity Hospital (Bas-Rhin) when an epidemic of influenza occurred in 1972-173. The virological diagnosis was made by carrying out separate serological estimations on 1940 pregnant women. It can be shown that the mean birthweight dropped in infants of mothers who had contracted influenza during pregnancy even when corrections were made for sex and the duration of the pregnancy. The drop in weight of the placenta (37.3 g as a mean) was more obvious and can totally explain the drop in fetal weight. It was not possible to demonstrate any increase in the number of congenital malformations that were found in the neonatal period in the infants born to women who had had influenza. These results suggest that there is no direct passage of the influenza virus across the placenta which, however, is itself modified by the infection.

[Prenatal diagnosis of neural tube defects. Value of electrophoresis of cholinesterases]. / Diagnostic prénatal des défauts de fermeture du tube neural. Intérêt de l'électrophorèse des cholinestérases.

Cholinesterase electrophoresis was performed in 802 amniotic fluids and its value in the detection of neural tube defects was compared with those of ultrasonography and amniotic fluid alpha-foetoprotein levels. Cholinesterase electrophoresis confirmed the ultrasonic diagnosis in 51 cases of neural tube abnormality and made it possible to diagnose neural tube defect in 6 other cases which had remained undetected by ultrasound and by alpha-foetoprotein level measurements. When our technique is used before the 28th week of gestation, false-positive results concern abnormalities which are easily detected by ultrasound (omphalocele, Bonnevie-Ullrich syndrome, sacrococcygeal tumour). We did not observe any false-negative result.