[Male-female cotherapists in marital therapy : a treatment underestimated.]

This article introduces a less usual type of marital therapy. It describes the advantages and the difficulties of a team of male-female cotherapists in jointly conducting a marital therapy. Could this psy-chotherapeutic process allow the couple to better settle relational impasses and learn more rapidly to face the challenges inherent to life as a couple? Drawing from their personal experiences as cotherapists, the authors discuss this issue. They constantly underline the specificity and the implications of this type of therapeutic approach in the precise framework of a systematic-interactional model.

The comet assay as a repair test for prenatal diagnosis of Xeroderma pigmentosum and trichothiodystrophy

Xeroderma pigmentosum (XP) and trichothiodystrophy (TTD) are autosomal recessive diseases associated with extreme cutaneous photosensitivity, a defect in nucleotide excision repair (NER), and genetic complexity. Severe prognosis and lack of treatment led families at risk to request genetic counseling. Unscheduled DNA synthesis (UDS) is the classic method for diagnosis and requires 4 to 5 wk before conclusion. The use of the alkaline comet assay (single cell gel electrophoresis assay) is proposed as a simple repair test for earlier prenatal diagnosis. Amniotic or chorionic villus cells in two pregnancies at risk for XP and one for TTD were examined in comparison with skin fibroblasts of family members or with repair-proficient or -deficient control cells. The comet assay and the UDS test were performed in parallel. In repair-proficient cells, DNA strand breaks due to the incision of UV-induced DNA damage result in increased migration of high molecular weight DNA in the comet assay. Fetal cells demonstrate repair capacity similar to that of fibroblasts. In incision repair-deficient XP and TTD cells, after post-UV incubation, migration does not occur and comet moments are reduced. Two fetuses belonging to two XP families responded normally and were diagnosed as unaffected. Fetal cells in a TTD family had reduced comet moments and a low UDS. This fetus was diagnosed and confirmed later as affected. Heterozygotes had normal responses with both assays. The comet assay offers discrimination similar to that of the UDS assay in identifying NER-deficient phenotypes. Practical advantages in view of prenatal diagnosis include the reduced number of cells required, a 24-h delay in obtaining results, and no need for radioactivity.

Recovery of normal DNA repair and mutagenesis in trichothiodystrophy cells after transduction of the XPD human gene

To determine whether expression of the XPD/ERCC2 repair gene in trichothiodystrophy (TTD) group D cells could restore mutagenesis characteristics of repair-proficient cells, we compared the UV mutagenesis of normal cells, TTD group D cells, and TTD group D cells retrovirally transduced by the wild-type XPD/ERCC2 gene (TTD + ERCC2 cells). We first verified the expression of the XPD protein, correction of UV cell survival, and DNA repair ability of TTD + ERCC2 cells. UV-induced mutations were studied using the pR2 shuttle vector. The addition of the XPD/ERCC2 gene in TTD cells led to a significant but partial decrease of mutation frequency compared with the parental TTD cells. Types of mutations of TTD + ERCC2 cells get closer to those observed in normal cells (ie., a reduction of multiple mutations). New hotspots appeared and some disappeared in the complemented line, suggesting that hotspot distribution is particular to each cell line and cannot be correlated with the repair status of the cells. In conclusion, the expression of the XPD/ERCC2 repair gene completely corrected UV hypersensitivity and almost all types of mutations of TTD group D cells, whereas hypermutagenesis was partially corrected.

Cell survival and shuttle vector mutagenesis induced by ultraviolet A and ultraviolet B radiation in a human cell line

Although it is known that sunlight is carcinogenic,few molecular data are available concerning the mutagenic effects of ultraviolet (UV) B (290-320 nm) and UVA (320-400 nm) radiation in human cells. To analyze the biologic effects of UVA and UVB, we irradiated the 293 human cell line, derived from adenovirus-transformed human embryonic kidney cells, in which we had stably introduced a shuttle vector harboring the lacZ' bacterial gene as the mutagenesis target. Identical cell survival occurred after UVA doses 700-fold higher than UVB. This comparable to the UVA/UVB ratio that reaches the basal cell layer of the skin after sunlight exposure with UVB sunscreen. The frequency of UVA- and UVB- induced mutations increased with the UV dose as cell survival decreased. At cell survival levels greater than 10%, UVA and UVB induced similar frequencies of mutations in the episomal lacZ gene, whereas for cell survival lower than 10%, UVA induced twice as many mutations as UVB. Sequence analysis of 81 independent lacZ mutants (36 UVA- and 45 UVB-induced) revealed specific characteristics for some UV-induced-mutations, particularly for UVB. Mutations at A/T base pairs were induced more frequently by UVA than by UVB. The UVA-induced mutation spectrum that we have observed in human cells may help help to elucidate the mechanism of skin carcinogenesis.

Characteristics of UV-induced mutation spectra in human XP-D/ERCC2 gene-mutated xeroderma pigmentosum and trichothiodystrophy cells

To study the relationships between mutagenesis and carcinogenesis, we compared the mutations and their frequency induced by ultraviolet irradiation at 254 nm (UV-C) in XP-D (GM-08207B/XP6BE), TTD/XP-D (TTD1VI-LAS-KMT11) and wild-type (MRC-5V1) human cells. XP-D and TTD/XP-D cells, mutated in the same XP-D/ERCC2 gene, are deficient in nucleotide excision repair. Whereas XP-D patients develop early skin tumors, TTD patients do not exhibit abnormal levels of cancers. After verification of UV hypersensitivity and DNA repair defect of the immortalized cell lines XP-D and TTD compared with a wild-type cell line, UV-induced mutagenesis was studied with a new shuttle vector pR2, carrying the target lacZ' gene. The UV-mutation frequencies in XP-D and TTD cells were similar and significantly increased compared with normal cells. Sequence analysis of 312 independent mutant plasmids revealed that more rearrangements were induced in TTD cells (16%) than in XP-D (5%) and normal cells (1%), while XP-D cells exhibited a twofold higher rate of tandem mutations compared with TTD and normal cells. In the three cell lines, a predominance of G:C to A:T transitions was found, especially in chiefly on the cytosine at 5'-TC-3' sites. The types of UV-induced point mutations in TTD cells were, however, more similar to those in normal cells than those found in XP-D cells. XP-D mutations were preferentially located in 5'-TCPur-3' sites, while mutations in normal and TTD cells were mostly at 5'-TCC-3' sites. Analysis of mutation spectra revealed differences in the location of the mutational hotspots between the three lines. Although the mutation frequency of the UV-irradiated pR2 vector is much higher in TTD and XP-D cells than in normal cells, the mutation spectrum is closer between TTD and normal cells as compared with XP-D cells. These dissimilarities could contribute to an explanation of some of the differences between the two syndromes.

Development of a new easy complementation assay for DNA repair deficient human syndromes using cloned repair genes

Nucleotide excision repair (NER)-deficient human cells have been assigned so far to a genetic complementation group by a somatic cell fusion assay and, more recently, by microinjection of cloned DNA repair genes. We describe a new technique, based on the host cell reactivation assay, for the rapid determination of the complementation group of NER-deficient xeroderma pigmentosum (XP), Cockayne's syndrome (CS) and photosensitive trichothiodystrophy (TTD) human cells by cotransfection of a UV-irradiated reporter plasmid with a second vector containing a cloned repair gene. Expression of the reporter gene, either chloramphenicol acetyltransferase (CAT) or luciferase, reflects the DNA repair ability restored by the introduction of the appropriate repair gene. All genetically characterized XP, CS and TTD/XP-D cells tested failed to express the UV-irradiated reporter gene, this reflecting their NER deficiency whereas cotransfection with the repair plasmid expressing a gene specific for the given complementation group increased the enzyme activity to the level reached by normal cells. Selective recovery of both reporter enzyme activities was observed after cotransfection with the XPC gene for the XP17VI cells and with the XPA gene for both XP18VI and XP19VI cells. Using this method, we assigned three new NER-deficient human cells obtained from patients presenting clinical symptoms described as classical XP to either XP group A (XP18VI and XP19VI) and XP group C (XP17VI). Therefore, this technique increases the range of methods now available to determine the complementation group of new NER deficient patients with the advantage, unlike the somatic cell fusion assay or the microinjection procedure, of being simple, rapid, and inexpensive.

Stable SV40-transformation and characterisation of some DNA repair properties of fibroblasts from a trichothiodystrophy patient

To characterize nucleotide excision repair properties of cells from trichothiodystrophy (TTD) patients genetically-related to the xeroderma pigmentosum (XP) group D, TTD skin fibroblasts from two unrelated patients (TTD1VI and TTD2VI) belonging to the TTD/XPD group were transformed with a plasmid containing SV40 large T antigen-coding sequences and some DNA repair properties, such as unscheduled DNA synthesis (UDS), UV-survival, in vitro repair synthesis of cell extracts and reactivation of UV-irradiated reporter plasmid were studied. Results showed that: a) both untransformed and transformed TTD cells present a reduced UV-survival, compared to wild-type cells, but at significantly less reduced levels than XP-D cells; b) reduced repair activities were detected in both TTD and XP-D transformed cells by using in vitro cell free extract repair and reactivation of UV-irradiated plasmid procedures, and these relative reduced extents correlated with respective UV-survival; c) surprisingly, near wild-type UDS levels were detected in TTD2VILas transformed cells at different passages after the crisis, suggesting a phenotypic reversion of this transformed cell line; d) fluoro-cytometric analysis of TTD2VILas cells revealed a strong increase of a cell population containing a DNA amount more than twice as high than that of untransformed cells; finally, e) when UDS data were normalized to the DNA content in TTD2VILas cells, it appeared that the repair efficiency was only slightly higher than in untransformed cells. This implies that in transformed cells DNA repair properties should be evaluated, taking into account additional parameters. We obtained an immortalized TTD cell line which maintains DNA repair properties similar to those of parental untransformed cells and may be used to characterize the TTD defect at genetic, molecular and biochemical levels.

Correction by the ERCC2 gene of UV sensitivity and repair deficiency phenotype in a subset of trichothiodystrophy cells

Trichothiodystrophy (TTD) is a rare genetic disease with heterogeneous clinical features associated with specific deficiencies in nucleotide excision repair. Patients have brittle hair due to a reduced content of cysteine-rich matrix proteins. About 50% of the cases reported in the literature are photosensitive. In these patients an altered cellular response to UV, due to a specific deficiency in nucleotide excision repair, has been observed. The majority of repair-defective TTD patients have been assigned by complementation analysis to group D of xeroderma pigmentosum (XP). Recently, the human excision repair gene ERCC2 has been shown to correct the UV sensitivity of XP-D fibroblasts. In this work we describe the effect of ERCC2 on the DNA repair deficient phenotype of XP-D and on two repair-defective TTD cell strains (TTD1VI and TTD2VI) assigned by complementation analysis to group D of XP. ERCC2 cDNA, cloned into a mammalian expression vector, was introduced into TTD and XP fibroblasts via DNA-mediated transfection or microneedle injection. UV sensitivity and cellular DNA repair properties, including unscheduled DNA synthesis and reactivation of a UV-irradiated plasmid containing the chloramphenicol acetyltransferase reporter gene (pRSVCat), were corrected to wild-type levels in both TTD and XP-D cells. These data show that a functional ERCC2 gene is sufficient to reestablish a wild-type DNA repair phenotype in TTD1VI and TTD2VI cells, confirming the genetic relationship between TTD and XP-D. Furthermore, our findings suggest that mutations at the ERCC2 locus are responsible for causing a similar phenotype in TTD and XP-D cells in response to UV irradiation, but produce quite different clinical symptoms.

[QT prolongation and circulatory arrest after an injection of erythromycin in a newborn infant]

A 8 day-old full-term newborn showed severe cardiac disturbances after intravenous injection of erythromycin. The neonate, suspected of having Chlamydia pneumonitis because of tachypnea and rhinitis, had been given 5 injections of erythromycin without clinical effect. Pallor, vomiting and bradycardia developed a few minutes after the 6th injection, and ECG showed ventricular arrhythmia, prolonged QT interval and an atrioventricular block. The infant died in intensive care unit. This case and the analysis of other published cases of cardiac disturbances following the parenteral use of erythromycin, indicate the potential arrhythmogenic risk of this drug. It is suggested that newborns treated with erythromycin should be monitored by ECG.

Constraints in simian virus 40 (SV40) encapsidation, as determined by SV40-based shuttle viruses

Simian virus 40 (SV40)-based shuttle vectors, containing the SV40 late genes, can be packaged as infectious pseudovirions. In terms of their function as bacterial plasmids, modifications in the overall size of these plasmids can be tolerated within a very wide range, which has allowed us to determine the requirements for SV40 encapsidation, free of the more stringent limitations of SV40 virus. Monkey COS7 cells were transfected with over- and undersized SV40-based shuttle virus plasmids and their progeny have been analysed to follow the stability and evolution of these genomes. Two of the three plasmids analysed undergo recombination, generating molecules with sizes of between 4.0 and to 4.8 kb which were selected after multiple lytic cycles. This size range may correspond to the DNA lengths preferentially packaged in SV40 capsids. The structure of the rearranged plasmids indicates that there is a strong selective pressure for genomes that retain the functions necessary for replication and virus production. Depending on the parent DNA, two main classes of rearrangements were generated: duplications in tandem with the SV40 origin of replication and deletions. Both classes are probably a result of selective size and replicative advantages, which are then biologically amplified during plasmid transmission as virus particles.

Ornithine carbamoyltransferase deficiency. A new variant with subnormal enzyme activity

A new ornithine carbamoyltransferase variant is described with a nearly normal specific enzymatic activity. This new variant is characterized by a ten-fold increased Km value for L-ornithine (3.75 vs. 0.33 mmol/l in control) and by a normal Km value for carbamoylphosphate (0.42 vs. 0.29 mmol/l). Its pH optimum is shifted towards the alkaline side. This enzyme is highly unstable at 55 degrees C.

Respective roles of pyrimidine dimer and pyrimidine (6-4) pyrimidone photoproducts in UV mutagenesis of simian virus 40 DNA in mammalian cells

UV light induces DNA lesions which are mutagenic in mammalian cells. We used simian virus 40 tsB201 (unable to produce viral capsid at the restrictive temperature of 41 degrees C because of a point mutation in the VP1 gene) to analyze the mutagenic potency of the two major UV-induced lesions, pyrimidine dimers (Py-Py) and pyrimidine (6-4) pyrimidones [Py(6-4)Py], which are formed on the same nucleotide sites. The mutagenesis criterion was the reversion toward a wild-type growth phenotype. After UV irradiation (mainly at 254 nm), part of the DNA was treated with the photoreactivating enzyme of Escherichia coli, which monomerizes Py-Py but does not modify the Py(6-4)Py photoproduct. Higher survival and lower mutation frequency rates for the photoreactivated DNA indicated that the two lesions were lethal and mutagenic. The VP1 gene of some mutants was entirely sequenced. The mutation spectra showed that the two lesions did not induce the same mutation hot spots, although some sites were common to both. The induced mutation hot spots were not only correlated with lesion hot spots but seemed partially directed by local DNA structures.

Enhanced mutagenesis of UV-irradiated simian virus 40 occurs in mitomycin C-treated host cells only at a low multiplicity of infection

Treatment of monkey kidney cells with mitomycin C (MMC) 24 h prior to infection with UV-irradiated simian virus 40 (SV40) enhanced both virus survival and virus mutagenesis. The use of SV40 as a biological probe has been taken as an easy method to analyse SOS response of mammalian cells to the stress caused by DNA damage or inhibition of DNA replication. The mutation assay we used was based on the reversion from a temperature-sensitive phenotype (tsA58 mutant) to a wild-type phenotype. The optimal conditions for producing enhanced survival and mutagenesis in the virus progeny were determined with regard to the multiplicity of infection (MOI). Results showed that the level of enhanced mutagenesis observed for UV-irradiated virus grown in MMC-treated cells was an inverse function of the MOI, while enhanced survival was observed at nearly the same level regardless of the MOI. For the unirradiated virus, almost no increase in the mutation of virus progeny issued from MMC-treated cells was observed, while a small amount of enhanced virus survival was obtained. These results show that enhanced virus mutagenesis and enhanced virus survival can be dissociated under some experimental conditions. Enhanced virus mutagenesis, analogous to the error-prone replication of phages in SOS-induced bacteria, was observed, at least for SV40, only when DNA of both virus and host cells was damaged and when infection occurred with a small number of viral particles. We therefore hypothesize that an error-prone replication mode of UV-damaged templates is observed in induced monkey kidney cells.

Acute cardiopulmonary effects of nitroglycerin in canine oleic acid pulmonary edema

In a canine model of acute respiratory failure, the authors investigated acute cardiopulmonary effects of nitroglycerin (TNG) and compared the results with those obtained after phlebotomy. Oleic acid increased intrapulmonary shunt (Qs/Qt) from 7.4 to 31% (P less than 0.001) and decreased (P less than 0.01) cardiac output (CO). In the presence of assumed low-pressure pulmonary edema, TNG was infused to decrease mean blood pressure (BP) by 40%; this was associated with a 26% decrease (P less than 0.05) in CO. Qs/Qt increased from 31 to 42% (P less than 0.01). There was a slight increase (P less than 0.01) in pulmonary vascular resistance (PVR) with TNG, and mean pulmonary artery pressure (PAP) decreased (P less than 0.05). In contrast, when CO was decreased by a similar amount with phlebotomy, mean Qs/Qt did not significantly change. There were similar changes in PVR and PAP and mixed venous O2 tension with TNG and phlebotomy. Accordingly, current results rule out increased flow, increased PVO2, and mechanical alterations in pulmonary vascular pressures as contributory to the increase in Qs/Qt with TNG. Alternatively, the increase in Qs/Qt with TNG may be explained by a direct pharmacologic decrease in pulmonary hypoxic vasoconstriction and/or by nonspecific pharmacologic effects.

Molecular analysis of mutagenesis in mammalian cells

Mammalian cells are constantly facing various types of mutagens. However, due to the high complexity of the cell genome, the molecular analysis of mutagenesis has not yet been possible. Therefore, we have used simian virus 40 (SV40) as a biological and molecular probe to characterize mutagenesis at the nucleotide level. By using a reversion assay from a temperature-sensitive phenotype towards a wild-type phenotype, we have analysed mutagenesis induced by u.v.-light and by apurinic sites (Ap sites). We report here experiments allowing us to quantify and to compare the mutagenic efficiency of various DNA lesions measured on the SV40 genome. The Ap sites are very mutagenic in this type of assay. The molecular analysis of u.v.-induced mutagenesis reveals that mutations correspond to single base-pair substitutions always located opposite Py-Py lesions. The mutations are almost equally distributed between transition and transversion types, and between the 5' and the 3' side of the Py-Py targets. These results demonstrate for the first time in animal cells the existence of targeted mutations induced by u.v.-light. We propose therefore, the use of SV40 as an efficient biological and molecular probe for assaying mutagenic pathways in mammalian cells.

[Acquired toxoplasmic chorioretinitis with a late onset]

Maternal toxoplasma infection was responsible for congenital toxoplasmosis with ocular and cerebral manifestations in the infant. The acquired character of the toxoplasmosis in the 5th month of pregnancy was confirmed by serologic data and isolation of the parasite from the placenta. Five years later, an evolutive chorioretinitis was found in the mother. The toxoplasma origin of the ocular injury was proven by the study of aqueous humor. This case report is compared with the rare similar cases in the literature. The late discovery of ocular impairment is discussed.

[Prevention of symblepharon in severe ocular burns. Apropos of 3 cases]

The prevention of symblepharon formation in severe ocular burns can be achieved simply, innocuously and economically, by the application of hen's egg allantoic membrane. Three cases of burns caused by tear gas, sulphuric acid and quicklime were treated by this procedure. The operative procedures, including the membrane preparation and dissection techniques, and methods of applying this membrane to the eye are described. The various advantages of this very old technique, which is apparently not very well-known, are discussed.

Error-prone replication of ultraviolet-irradiated simian virus 40 in carcinogen-treated monkey kidney cells

To analyze the molecular mechanism of mutagenesis in carcinogen-treated mammalian cells, we developed a model system composed of various simian virus 40 (SV40) mutants as a biological probe to detect inducible DNA repair and mutagenesis in carcinogen-treated monkey kidney cells (CV1-P). Results have shown that treatment of cells with UV-light, acetoxy-acetyl-aminofluorene, or mitomycin C, increases the mutagenesis of UV-irradiated SV40 ts mutant measured as a reversion frequency from a thermosensitive phenotype toward a thermoresistant phenotype. This increased mutagenesis is not observed in the case of undamaged virus indicating that we are looking at targeted mutagenesis. The molecular analysis of several revertant genomes indicates that some DNA rearrangements may occur in the revertant genomes but in some cases the reversion site is a single basepair substitution located at positions different from the original thermosensitive mutation, which is still present. The general interpretation of our results leads to the conclusion that carcinogen treatment of monkey cells activates some kind of error-prone replication mode able to better replicate UV-damaged templates but leading to a higher level of mutagenesis. This activity may represent a SOS-like function in mammalian cells.

Gas-Liquid Chromatographic Determination of Terbuthylazine Technical and Its Formulations: Collaborative Study

Terbuthylazine technical and its 80% wettable powder were analyzed in a CIPAC collaborative study. The content and the identity were determined by gas-liquid chromatography on a column of 3% Carbowax K20M on Gas-Chrom Q, using di-n-pentylphthalate as the internal standard. Results obtained from 27 government, university, and industrial collaborators showed within-laboratory repeatability of 1.3% for the technical and 1.0% for the wettable powder. Reproducibility was 2.1% for both samples. The method has been adopted official first action

[Mesenchymatous tumour of the thigh causing hypoglycaemia with circulating protein of high insulin activity (author's transl)]

An 87-year-old woman underwent surgery for a dermato-fibrosarcoma of the thigh, responsible for hypoglycaemic episodes. There was a high level of NSILP contrasting with a low level of NSILAs. This is the second case where such a finding has been made in a patient suffering from an extra-pancreatic tumour causing hypoglycaemia. The possible aetiological role of NSILP in extra-pancreatic tumours causing hypoglycaemia is discussed.

[Autonomous thyroid nodule spontaneously cured by cystic degeneration on a thirteen aged girl (author's transl)]

On a thirteen-aged girl an autonomous thyroid nodule with hypersecretion, has run its course towards hemorragic necrosis with suppression of hypersecretion. If partial cystic degeneration of autonomous thyroid nodule is frequent, it rarely occurs when extra-nodular thyroid tissue is completely suppressed, with clinical "cure".

[Interest and limits of beta blocking drugs for preparing Grave's disease to sub-total thyroidectomy (author's transl)]

The use of beta blocking drugs as a preparation to the sub-total thyroidectomy in Graves's disease allows to shorten the pre-operation time. However, besides the observance of classical contraindications, it requires that patient who remain hyperthyroid are closely looked after. Within these limits, it seems to be quite useful for patients who need to quickly come back to euthyroid status.

Induction of an error-prone mode of DNA repair in UV-irradiated monkey kidney cells

The survival of UV-irradiated simian virus 40 (SV40) on UV-irradiated monkey kidney CV-1P cells at 33 degrees was increased over survival on unirradiated cells. During this process - called induced-virus reactivation - the progeny virus yielded by UV-irradiated cells had a much higher mutation frequency than did the progeny from unirradiated cells. Mutation rates were quantified by using phenotypic reversion towards wild-type growth of an early (tsA 58) or a late (tsB 201) temperature-sensitive SV40 mutant. Analysis of SV40 revertant genomes indicated that no detectable deletions of additions were responsible for the reversion process. These results suggest that enzymes from UV-irradiated cells are able to replicate UV-irradiated DNA by an error-prone mode of DNA repair. Induced virus reactivation and error-prone replication are probably one of the expressions of SOS functions in mammalian cells.

[Mesenchymal tumor associated with hypoglycemia and an elevated NSILP (author's transl)]

An unusually located mesenchymal tumor with hypoglycemia is observed. Insulin, cortisol, growth hormone, glucagon levels are within the normals. The glucogenic aminoacids have also been measured, as well as the NSILP which was three times as high as the upper limit of normal values. The various processes which might have brought about the patient's hypoglycemia are discussed.

Conservative management of patent ductus arteriosus in preterm infants

We report our experience of medical treatment, chiefly based on prolonged artificial ventilation, of 33 preterm infants with PDA and heart failure whose survival rate was 88%. All of them had clinical criteria used by others to indicate surgical ligation of the ductus arteriosus. This conservative approach seems to give better results than surgical ligation, despite a high frequency of bronchopulmonary dysplasia among survivors.

[Senile common bile duct. Radiological study]

From this study carried out under sufficiently strict conditions to analyze normal common bile ducts of the third to the tenth decade, with radio-geometric measurement redusurement reducing errors as far as possible, it appears that: a) there is no difference in the frequency and the density of opacification of the bile duct in young or elderly subjects, b) that the radiological diameter of the normal bile duct becomes enlarged with time, according to the formula: (see article) which may be considered in routine clinical practice as a true increase in diameter of about 1 mm per decade. The limits of true diameter of the bile duct, in our experience, were +/- 3 mm at 30 years to +/- 7 mm after 80 years.

[Metabolism and in vitro binding of several organochlorine and organophosphate pesticides to calf thymus DNA and rat liver microsomal proteins]

The organophosphorus insecticide ethyl-parathion was transformed by rat liver microsomes into metabolites which were bound to calf thymus DNA, in large amount. When the rats were treated by phenobarbital or 3-methylcholanthrene, the metabolite binding to DNA was increased two-fold. By contrast, in the same conditions, the organochlorine insecticides, aldrin, dieldrin and gamma hexachlorocyclohexane (lindane), did not yield metabolites able to bind to DNA and to proteins.