The nuclear pore complex is involved in nuclear transfer of plasmid DNA condensed with an oligolysine-RGD peptide containing nuclear localisation properties

One of the major barriers to efficient gene transfer and expression of nonviral vectors for gene therapy is passage across the nuclear envelope. We have previously shown that an oligolysine-RGD peptide that condenses plasmid DNA and binds to cell surface integrins can mediate increased internalisation of plasmid DNA into cells and synergistic enhancement of gene expression when complexed to a cationic lipid. In this report, we show that this enhancement is due to increased nuclear transfer of the plasmid DNA. We have applied the digitonin-permeabilised cell system that has been well established for the study of the nuclear transport of proteins to examine the nuclear transfer of plasmid DNA. Nuclear transfer of plasmid DNA complexed to an oligolysine-RGD peptide and lipofectamine appears to be an energy-dependent process involving the nuclear pore complex, since it is inhibited at 4 degrees C and by treatment with wheat germ agglutinin or with an antibody to the nuclear pore complex which all block nuclear protein import. In accordance with active nuclear transport, we have shown that all these treatments inhibit expression of a luciferase reporter plasmid in permeabilised cells. Nuclear transfer of pDNA is enhanced in mitotic cells, but cell division is not a prerequisite for transfer. We propose that the oligolysine-RGD peptide acts as a nuclear localisation signal and that the cationic lipid is more important for cell entry and endosome destabilisation than nuclear transfer.

Establishment and characterization of immortalized ovine Sertoli cell lines

The objective of this study was to generate immortalized Sertoli cell lines from prepubertal lamb testes to facilitate investigations during the course of testicular differentiation. The Sertoli cells were enzymatically isolated and immortalized by transfection, with the sequences coding for the SV40 large T-antigen fused downstream of regulatory elements from the human vimentin gene. The different cell lines were positively stained with antibodies to vimentin and transferrin, in agreement with their Sertoli origin. Reverse transcriptase polymerase chain reaction was used to analyze the specific expression of molecular markers (clusterin/sulfated glycoprotein ISGP-2], follicle-stimulating hormone [rFSH], alpha-inhibin, anti-Müllerian hormone, Wilms' tumor gene [WT-1], steroidogenic factor 1 [SF-1], SRY-related HMG box gene g [SOX9], and sex-determining region of Y chromosome) normally expressed in this cellular type. All were shown to express messenger ribonucleic acids for SGP-2, alpha-inhibin, WT-1, SOX9, and SF-1 (except SF-1 for clone no. 1). Moreover, we performed alkaline phosphatase and receptor tyrosine kinase p145 (c-kit) detection to ensure the absence of contamination by peritubular, germ cells, and Leydig cells. Both tests were negative for all the seven cell lines. These ovine Sertoli cell lines are the first ones obtained from livestock that exhibit specific Sertoli cell characteristics resembling different stages of phenotypic development. They provide useful in vitro model systems for toxicological investigations, coculture, and transfection experiments, making it possible to study signal transduction pathways, cell-cell interactions, and gene expression in species other than rodents.

Differences in sulfation patterns of heparan sulfate derived from human bone marrow and umbilical vein endothelial cells

OBJECTIVE

Heparan sulfates (HS), the polysaccharide side chains of HS proteoglycans, differ in structure and composition of sulfated domains among various tissue types, resulting in selective protein binding. HS proteoglycans on bone marrow endothelial cells (BMEC) could contribute to tissue specificity of the bone marrow endothelium and play a role in the presentation of chemokines such as stromal cell-derived factor-1 (SDF-1) and adhesion of hematopoietic progenitor cells after stem cell transplantations. We characterized differences in HS structure and SDF-1 binding between BMEC and human umbilical vein endothelial cells (HUVEC).

MATERIALS AND METHODS

Expression of HS proteoglycans on human bone marrow microvessels was investigated by immunohistochemical staining. Comparison of three human BMEC cell lines with HUVEC and an HUVEC cell line was studied by flow cytometry using antibodies against different epitopes of the HS polysaccharide chain. HS proteoglycans were biochemically characterized after isolation from metabolically labeled cultures of the BMEC cell line 4LHBMEC and HUVEC. Binding of radiolabeled SDF-1 to 4LHBMEC and HUVEC and competition with heparins were investigated.

RESULTS

Bone marrow microvessels constitutively expressed HS proteoglycans. Flow cytometric experiments showed differences in HS chain composition between BMEC and HUVEC. Biochemical characterization revealed more O-sulfation of the N-sulfated domains present in cell-associated HS glycosaminoglycans in 4LHBMEC compared to HUVEC. Binding experiments showed that 4LHBMEC bound more 125[I]-SDF-1 per cell than HUVEC. This could be inhibited largely by heparin and O-sulfated heparin and to a lesser extent by N-sulfated heparin.

CONCLUSIONS

Cellular HS from BMEC differs in composition from HUVEC. We postulate that the presence of highly sulfated domains in the HS chains from BMEC contributes to tissue specificity of bone marrow endothelium in which HS may be involved in SDF-1 presentation and adhesion of hematopoietic progenitor cells.

Human immortalized brown adipocytes express functional beta3-adrenoceptor coupled to lipolysis

Human brown pre-adipocytes were immortalized by microinjection of the genes encoding simian virus 40 T and t antigens under the control of the human vimentin promotor. The transfected pre-adipocytes were cultured for several months with no loss of their morphological characteristics. These cells accumulate lipids and differentiate into adipocytes when treated with insulin, triiodothyronine and dexamethazone. The mRNA of various adipocyte markers was detected by reverse transcriptase-polymerase chain reaction analysis, including hormone-sensitive lipase, lipoprotein lipase, adipsin, glucose transporters 1 and 4, the uncoupling protein (specific of brown adipocytes), and leptin, the product of the ob gene. Pharmacological analyses indicated that the beta3-adrenoceptor is the predominant beta-adrenoceptor subtype in PAZ6 cells and that this receptor subtype is functionally coupled to adenylate cyclase and lipolysis. The immortalization of human adipocytes will permit pharmacological analysis of the human beta3-adrenoceptor function in adipose cells and will allow detailed studies of human adipocyte differentiation.

Characterization of a newly established human bone marrow endothelial cell line: distinct adhesive properties for hematopoietic progenitors compared with human umbilical vein endothelial cells

Human bone marrow endothelial cells (HBMEC) are intimately involved in the homing of hematopoietic progenitor cells (HPC) to the bone marrow and in the regulation of proliferation and differentiation of these cells. Because availability of primary HBMEC and their capacity to be cultured in vitro are limited, we used isolated HBMEC to establish a cloned cell line by microinjection of a recombinant plasmid expressing simian virus 40 early genes under the control of a deletion mutant of the human vimentin promoter. Serum requirements for growth of a transformed HBMEC line (TrHBMEC) were markedly decreased compared with those of primary cells, and added growth factors were not required for proliferation. Cells took up acetylated low-density lipoprotein normally, bound to Ulex europaeus lectin, and stained positively for von Willebrand factor, P-selectin, CD31, CD34, CD44, very late antigen-5, and intercellular adhesion molecule-2 (ICAM-2). After treatment with TNF-alpha or lipopolysaccharide, TrHBMEC increased surface expression of E-selectin, vascular cell adhesion molecule-1 (VCAM-1), and ICAM-1 in a manner similar to primary HBMEC. In contrast, IL-1 beta elicited much less up-regulation of these adhesion molecules than in primary cells. In previous work, we reported that, in a flow adhesion model, rolling of peripheral blood CD34+ cells on primary HBMEC was E-selectin-dependent, whereas VCAM-1 and ICAM-1 contributed to firm adhesion. In the present study, we show that HPC adhere in a similar way to TrHBMEC. A less-pronounced role for VCAM-1 and ICAM-1 was found in the adhesion of HPC to human umbilical vein endothelial cells. Furthermore, significantly more CD34+ cells adhered to TNF-alpha-stimulated HBMEC and TrHBMEC than to similarly stimulated human umbilical vein endothelial cells. These data emphasize the importance of using microvessel HBMEC for studying the homing of HPC to the bone marrow, and indicate the usefulness of the above-described bone marrow endothelial cell line.

Transcription of Y- and X-linked genes in preimplantation ovine embryos

Because male ovine embryos develop faster than female embryos, the transcription of SRY and ZFY, two genes located on the Y chromosome, was examined in preimplantation stages using the reverse transcriptase polymerase chain reaction (RT-PCR). RNA was extracted from pools of ovine embryos matured and fertilized in vitro then cultured in synthetic oviduct fluid medium and recovered from 24 to 207 hr post-insemination (two-cell up to hatched blastocyst stage). Since primers used to amplify ZFY also amplify the homologue ZFX, located on the X chromosome, transcripts were differentiated by digestion with restriction enzymes. ZFY and ZFX transcripts were present in all stages examined following RT-PCR, whereas transcripts for SRY were undetectable in all investigated stages following either RT nested PCR or Southern analysis. The presence of ZFY transcripts suggests that Y chromosome is transcriptionally active during early ovine preimplantation development. The possible relationship between a faster growth of male embryos and the transcription of Y-linked genes at early stages of development is discussed.

Spatial and temporal patterns of c-kit-expressing cells in WlacZ/+ and WlacZ/WlacZ mouse embryos

In the mouse, the Kit receptor and its ligand, the stem cell factor (SCF), are encoded at the W/Kit and Steel loci, respectively. The Kit/SCF transduction pathway is involved in promoting cellular migration, proliferation and/or survival of melanoblasts, hematopoietic progenitors and primordial germ cells. Furthermore, a functional Kit/SCF pathway is required for the development of interstitial cells of Cajal (ICC) in the small intestine. Whereas all c-kit-expressing cells in embryogenesis were not identified, previous studies clearly demonstrated that the c-kit expression pattern extends well beyond cells known to be affected by W mutations. To investigate further Kit function, we specifically marked the c-kit-expressing cells and followed their fate during embryogenesis. A mutation was introduced by gene targeting at the W/Kit locus in mouse embryonic stem cells. The lacZ reporter gene was inserted into the first exon of c-kit, thus creating a null allele, called WlacZ. The lacZ expression reflects normal expression of the c-kit gene in WlacZ/+ embryos. The comparison of the patterns of lacZ-expressing cells between WlacZ/+ and WlacZ/WlacZ embryos allowed us to detect where and when melanoblasts, primordial germ cells and hematopoietic progenitors failed to survive in the absence of Kit. We also observed that ICC express c-kit during embryogenesis. ICC are found identically in WlacZ/+ and WlacZ/WlacZ embryos. Therefore, ICC do not depend on Kit expression during embryogenesis. These results indicate that the function of the c-kit gene is only required for the postnatal development of the ICC. Unexpected sites of c-kit expression were uncovered in embryos, including endothelial, epithelial and endocrine cells. None of these cells are dependent on Kit expression for their migration, proliferation and/or survival during embryogenesis. Nevertheless, we assume that the Kit/SCF pathway could be involved in the growth of transformed endothelial, epithelial and endocrine cells.

Sex-related differences in the developmental rate of in-vitro matured/in-vitro fertilized ovine embryos

Sex determination of in-vitro matured/in-vitro fertilized ovine embryos cultured in synthetic oviduct fluid (SOF) medium was performed by the polymerase chain reaction amplification of specific Y DNA sequences so as to test the influence of sex on developmental growth during the preimplantation period. At 144 h post-insemination, embryos with a blastocoel were classified as the fast-developing group, whereas those showing a blastocoel only after this length of time were classified as the slow-developing group. At 144 h post-insemination, fast-developing embryos were cultured separately and some were classified according to the size of their blastocoel. At the end of culture (207 h post-insemination), all embryos were classified according to both their developmental stage and their morphological quality. The male:female sex ratio of fast-developing embryos was significantly higher than the expected ratio of 50%. More males were observed at the most advanced developmental stage at both 144 and 207 h post-insemination. The proportion of males did not differ between the good- and poor-quality groups, although a skewed sex ratio was observed with embryos of better quality at the most developed stage. In conclusion, embryos at the most developed stage were predominantly male and were derived mainly from the fast-developing group, raising the possibility of a deviation in the sex ratio after the transfer of in-vitro matured/in-vitro fertilized ovine embryos.

Influence of culture system and oxygen tension on the development of ovine zygotes matured and fertilized in vitro

The development and quality of ovine zygotes matured and fertilized in vitro were compared after coculture with oviductal cells (CZB-199 system) and culture in synthetic oviduct fluid medium without cells (SOF system). The effect of two oxygen concentrations (5% and 20%) on the development of ovine zygotes in SOF medium was also studied. More ovine zygotes reached the blastocyst stage when culture in SOF medium was performed in 5% O2 rather than 20% O2. A greater number of blastocysts was obtained after culture in the SOF system than coculture in the CZB-199 system. Proportions of grade I (excellent), II (good), III (fair) and IV (poor) blastocysts did not differ significantly between the SOF and CZB-199 systems. Histological examination of hatched blastocysts revealed a superiority of the SOF system for the following: a greater number of total and trophoblastic cells in grade I and II blastocysts; more endodermic cells in grade I blastocysts, higher mitotic index in the inner cell mass of grade II blastocysts and in total and trophoblastic cells of grade I, II and III blastocysts; more grade III blastocysts with mitosis in the inner cell mass; and a lower pyknotic index in the inner cell mass of grade I, II and III blastocysts. Culture in the SOF system improved the rate and quality of blastocysts in comparison with the CZB-199 system. Furthermore, culture in SOF medium with 5% O2 provided more blastocysts than culture in the presence of 20% O2.

Coculture of ovine zygotes fertilized in vivo or in vitro and positive effect of CZB medium on the development of in vitro fertilized zygotes

The development and quality of ovine zygotes derived from in vivo (IVOF) or in vitro fertilization (IVF) were compared after coculture on sheep oviductal cells. The same criteria were used to evaluate the coculture of IVF zygotes in CZB medium for 2 d followed by 199 medium for 6 d (CZB-199 coculture) or in 199 medium for 8 d (199 coculture). A higher overall developmental rate to blastocyst stages was obtained with IVOF (65.7%) than with IVF (23.2%) zygotes. More IVF zygotes reached blastocyst stages in CZB-199 (36.7%) than in 199 coculture (22.9%). The morphological aspect did not differ significantly between IVOF and IVF or between 199 and CZB-199 blastocysts. Histological examination revealed no significant difference in the pyknotic and mitotic indices and mean number of cells in the trophoblast and in the inner cell mass of hatched blastocysts between IVOF and IVF or between CZB-199 and 199 cocultures. According to criteria used in this study, the quality of blastocysts was equivalent, independently of fertilization or coculture systems. The use of CZB medium during the first cleavages increases the proportion of blastocysts.

Flecainide distribution, transplacental passage, and accumulation in the amniotic fluid during the third trimester of pregnancy

OBJECTIVE

To study the disposition of flecainide acetate and its transplacental passage (both into the fetus and in the amniotic fluid) during the third trimester of pregnancy.

DATA SOURCES

Reference articles and books are identified in the text. A literature review is presented.

CASE SUMMARY

Flecainide distribution, transplacental passage, and accumulation into the amniotic fluid were studied in a patient at term presenting with a fetal supraventricular tachycardia diagnosed at 33 4/7 weeks of gestation. The fetal tachycardia was accompanied by cardiac failure with placental anasarca and hydramnios. Flecainide 100 mg po bid was prescribed initially; by the time of delivery, the dosage had been decreased to 50 mg bid. At delivery day (39 5/7 weeks), the pharmacokinetics of total flecainide were studied at plateau.

DATA SYNTHESIS

The concentrations of flecainide at birth in fetal and maternal blood and in amniotic fluid were 235.4, 241.2, and 6426.5 micrograms/L, respectively. Calculation of a fetomaternal blood accumulation ratio of 0.97 showed that, at this gestational age, flecainide penetrates the placental membrane easily without accumulation in fetal blood. In contrast, the concentration of flecainide in amniotic fluid was approximately 27-fold that measured in maternal peripheral blood. Our results suggest the following: (1) close to term, the metabolic clearance (fetal hepatic clearance) of flecainide offers a high yield and its excretion by the fetal kidney is efficient; (2) given that amniotic fluid is constantly swallowed, it seems that, in contrast to what is seen in adults (relative oral bioavailability > or = 95 percent), the oral bioavailability of flecainide is possibly low in the fetus at term or close to term; under such circumstances, the drug would accumulate passively within the gestational sac; and (3) an alternative explanation is that the concentration in the fetus is, in part, the result of both transplacental crossing of the drug and reabsorption orally from the amniotic fluid.

CONCLUSIONS

The regular therapeutic monitoring of flecainide is necessary and sufficient in the mother as the concentrations found appear to accurately reflect the degree of fetal accumulation. Because previous studies in infants and children have indicated few toxic adverse effects attributed to flecainide, it appears that the risk to a sucking infant of ingesting toxic amounts of flecainide in human breast milk is very low. Finally, the child of the patient described here has normal initial growth and development at the present time. The transplacental penetration of a drug can be considered, according to gestational age and the disorder being treated, as being of no consequence, dangerous, or desirable. Flecainide appears to fall into this last category.

Immortalization of multiple cell types from transgenic mice using a transgene containing the vimentin promoter and a conditional oncogene

Differentiated clonal cell lines were obtained from transgenic mice carrying a recombinant gene composed of DNA coding for a temperature-sensitive mutant of the simian virus large T antigen under the control of regulatory elements of the human vimentin gene. In response to mitogenic factors the vimentin promoter is activated in the presence of serum in almost all cultured cells independently of their origin. The expression of the T antigen could be controlled both at the level of transcription since the vimentin promoter is growth-regulated and at the level of the protein structure through the temperature stability of the T antigen. Indeed, the switch-off of the oncogene protein is obtained by serum deprivation of the culture and achieved with enhancement of the growth temperature. From transgenic mice several types of clonal differentiated cell lines were established and characterized including melanocytes, macrophages, mesangial, muscle, and endothelial cells. Melanocytes displayed melanin while endothelial cells from brain and heart expressed the related factor VIII and low density lipoprotein absorption capacities. Mesangial cells from kidney exhibited numerous desmosomes. Typical markers of macrophages from bone marrow were observed while skeletal muscle cells fused and contracted.

Pharmacokinetics and protein binding of ceftriaxone during pregnancy

The purpose of the present work was to study the pharmacokinetics and the protein binding (free fraction of the drug) of ceftriaxone (CTX) during pregnancy. Nine pregnant women (ages, 20 to 34 years) whose gestational ages ranged from 28 4/7 to 40 5/7 weeks were included. The diagnosis of infection was established in all cases; i.e., four women had chorioamnionitis and five women had pyelonephritis. The following triple antibiotic therapy was infused with the aim of achieving cure: CTX, 2 g once every 24 h (constant rate over 60 min); tobramycin, 3 mg/kg of body weight once every 24 h; and ornidazole, 1 g/day. Two series of blood samples were collected, i.e., during the first day of treatment (on day 1), to establish the primary pharmacokinetic profile of CTX, and at the plateau (on day 7), to evaluate a possible accumulation of the drug. This was an open, noncompartmental study, with each patient serving as her own control. Concentrations of total and unbound CTX in serum were measured by a high-performance liquid chromatographic method. Pharmacokinetic analysis was done by a noncompartmental method. Data were compared by a Wilcoxon t test (a P value of < or = 0.05 was considered significant). Data were also compared with those obtained for healthy subjects who received similar treatments. (i) The tolerance to treatment was excellent, and in all cases patients had a complete remission without premature delivery. (ii) No accumulation of CTX was noted during the treatment, and the profiles of the drug determined at days 1 and 7 were not significantly different.(iii) The pharmacokinetic parameters measured in pregnant patients during the third trimester of pregnancy were similar to those measured in healthy subjects. (iv) Residual concentrations of total and unbound CTX measured at 24 h were greater than the MICs for allegedly susceptible organisms, both on day 1 and at steady state. (v) During the final 3 months of pregnancy, the dosage schedule of CTX (2-g infusion per day) required no particular adjustment (i.e., neither a loading dose nor any increase in the maintenance dose.)

Pharmacokinetics of cyclosporin A during pregnancy; monitoring of treatment and specific assays of cyclosporin, based on five liver transplant patients

Very little information is available concerning the pharmacokinetic behaviour and monitoring of cyclosporin A (CsA) during pregnancy, notably after liver transplant. Monitoring of blood levels of CsA is considered to be one of the best tools for evaluation of the efficacy of immunosuppressant treatment. The aim of this study was to bring together new information concerning pregnant women receiving immunosuppressant treatment with CsA and, in view of the special pathophysiological status of such patients, to compare pharmacokinetic profiles of changes in blood levels of CsA and of the combination of CsA plus metabolites. Specific (CsA-S kit) and a new non-specific (CsA-NS kit) assays of CsA were carried out in five hospitalized pregnant patients who had received liver transplants between the 6th and the 41st weeks of amenorrhea. The results of five cases investigated lead to the following conclusions: (1) The pharmacokinetic behaviour of native CsA in the pregnant woman between the 6th and 41st weeks of amenorrhea suggests no systemic accumulation nor any radical need for changes in dosage schedule as compared with a non-pregnant patient. (2) Monitoring based upon simultaneous use of the CsA-NS and CsA-S kits may be a source of analytical bias and hence confusion for the physician. (3) Determination of an experimental CsA-NS/CsA-S accumulation ratio (based upon analysis of single concentrations or processing of AUCs) is of interest only if specific assays involve not only CsA itself but also its principal metabolites. (4) Monitoring based upon single measurements of residual CsA levels only, is necessary and adequate. Furthermore, such an approach is less costly.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of microinjected DNA and RNA in early rabbit embryos: changes in permissiveness for expression and transcriptional selectivity

Gene expression in rabbit early development was investigated by microinjecting LacZ DNA and LacZ RNA in 1-cell and 2-cell embryos. Expression of LacZ DNA could not be obtained before 30-36 hpf, although synthetic LacZ RNA was translated from 12 hpf at the least. The onset of expression of microinjected DNA correlated with the 8- to 16-cell stage. This suggests that before this stage, there is a general negative control of gene expression. The arrest of in vitro development at the 2- to 8-cell stages did not inhibit LacZ expression, which still occurred at 33 hpf. In addition the inhibition of the first cleavage by nocodazole resulted in LacZ expression in 1-cell embryos. Expression of microinjected DNA thus occurs at a fixed time after fertilization and is independent of cleavages and of the second and subsequent DNA replications. Therefore, the changes in permissiveness for the expression of microinjected DNA in rabbit embryos are reminiscent of those in mouse embryos. Transcriptional selectivity in rabbit embryos was compared to that in early mouse embryos. In both species, Sp1-sensitive promoters were active and the promoter of simian virus 40 did not require far upstream enhancers before late cleavage stages; genes driven by the -447, +563 region of murine leukemia virus were repressed. In rabbit, however, the H-2Kb promoter active in mouse was silent. Altogether, the results illustrate a remarkable conservation of the characteristics of the transcription in early rabbit and mouse embryos and the independence of its resumption from the pattern of cleavage.

Transplacental passage of vancomycin during the second trimester of pregnancy

Pharmacokinetics and drug monitoring of vancomycin were studied at mid-pregnancy in a patient with chorioamnionitis due to Streptococcus agalactiae. The terminal half-life remained in the normal range (4-6 hours) because of an equivalent increase in both volume of distribution and total plasma clearance. Transplacental passage of the drug was observed. Monitoring is mandatory for prolonged vancomycin therapy, and the results should be available within 24 hours. The therapeutic regimen of 15-20 mg/kg every 12 hours was sufficient for this patient's chorioamnionitis. Serum drug levels and renal function should be measured before increasing the vancomycin dosage.

[Determination of the ratio of serum concentrations of tobramycin between fetus and mother at birth. A model of small scale pharmacokinetics]

Thirty women at term presenting with fever greater than or equal to 38 degrees C during labour were given a synergic combination of tobramycin-amoxicillin. Gestational ages ranged from 37 6/7 to 41 2/7 weeks. A single dose of 3 mg/kg of tobramycin was given every day intravenously. Feto-maternal tobramycin concentrations (F/M ratios) were systematically determined at birth and allowed to make a small scale pharmacokinetic study. Two curves were plotted from the pharmacokinetic analysis of maternal and fetal measurements, showing an intravenous and an intramuscular profile respectively. A high positive linear correlation (R = 0.82) was found between the F/M ratios and the time (delta T, -hours-) measured from the last administration to the mother to the time of delivery. Elimination of the aminoglycoside was slowed down in newborns (t1/2 lambda z = 5.1 hours). In newborns tobramycin levels were always less than or equal to 6 mg/l and still greater than or equal to 1 mg/l 6 hours after the last maternal injections. Measurement of F/M ratios allowed to study and compare the fetal and maternal pharmacokinetics facilitating (when necessary) the initial posologic adjustment in newborns. Such small scale pharmacokinetics could be extended, for a given gestational age, to other drugs with narrow therapeutic ranges. However, the size and the homogeneity of the population seem to be most important.

[Pharmacokinetics of methotrexate and clinical response associated in the medical treatment of ectopic pregnancies]

Methotrexate (MTX) is used in the medical treatment of unruptured ectopic pregnancy. This drug is administered by intramuscular (IM) or intrasaccular (IS) injection under sonographic control. No data are available concerning the pharmacokinetics of MTX in this new indication. This study compares the two administration routes in 12 patients (21 to 37 years) taken as their own control and presenting with ectopic pregnancy (51 +/- 12 days of amenorrhea). Our aim was to compare the pharmacokinetic profile of MTX for each route to facilitate its use in the future. The initial level of hCG was 4.474 +/- 4.184 mIU/ml. Each patient firstly received 1 mg/kg of MTX intrasaccularly under vaginal sonography. The same dose was injected intramuscularly 48 hours later. The pharmacokinetic profiles of MTX after IS and IM administrations were determined after both injections during 48 hours. MTX serum levels were measured by Fluorescence Polarization Immuno Assay. Data were analyzed by model independent methods and compared by a Wilcoxon T test (p 0.01 was considered as significant). All the unruptured ectopic pregnancy were cured and the hCG serum levels were normalized (10 mIU/ml) in 37 +/- 18 days. After IM administration, AUC0-infinity is significantly (p 0.01) increased i.e., 15.1 +/- 4.1 mumol.h/l versus 11.2 +/- 4.8 after IS injection. T1/2 lambda z and MRT remained unchanged whatever the route is i.e., 11.3 +/- 4.9 h and 8.6 +/- 3.9 h (IS) versus 12.1 +/- 5.9 h and 7.3 +/- 1.8 h (IM). The decrement of AUC0-infinity 8 determined after IS injection might be the consequence of the capture of the MTX by the trophoblastic cells (target cells).(ABSTRACT TRUNCATED AT 250 WORDS)

Establishment of porcine cell lines producing a murine recombinant retrovirus in order to transfer the nlslacZ gene into porcine cells

Swine testis (ST) cell lines producing a murine recombinant retrovirus (RRV) were established in order to transfer the bacterial lacZ gene fused to a nuclear location signal (nlslacZ) into animal cells. ST cells were infected with the supernatant of the cat G355.5LacZ2 cell line which produces amphotropic and xenotropic MMuLVSVnlslacZ-defective RRV and wild amphotropic and xenotropic MMuLV. Expression of the nlslacZ reporter gene was under the transcriptional control of both the SV40 early promoter and the retroviral LTR. ST cells expressing the reporter gene were sorted and cloned by limiting dilutions. Fourteen STLacZ-cell lines were isolated and subsequently tested for virus production. Depending on the host range of the retroviruses, two cell lines (STBF11 and STAA3) produced both a xenotropic recombinant pseudotype and wild retroviruses; another (STAB 10) produced both an amphotropic recombinant pseudotype and wild retroviruses. Southern blot analysis of the producer cell lines was carried out to verify proviral integration. The efficiency of the different pseudotypes in the transfer of the nlslacZ reporter gene to cultured animal cells, including porcine cells, was compared to the pseudotyped RRV produced by cat lines. Our results showed that the xenotropic RRV produced by the porcine STBF 11 cell line has a high titre for cells from different species and led to a higher number of porcine endothelial and lymphoblastoid cells expressing the reporter gene than did RRV produced by the cat packaging cell lines.

Pharmacokinetics of tobramycin in pregnant women. Safety and efficacy of a once-daily dose regimen

The pharmacokinetics of tobramycin, an aminoglycoside antibiotic, was investigated after a short intravenous infusion and once-daily dose regimen in two groups of nine pregnant women during the second (Group 1) and the third (Group 2) trimester of pregnancy. During these periods, the risk of infectious diseases is increased. Plasma concentrations of tobramycin were measured by fluorescence polarization immunoassay. The decrease in clearance (21%), at 28 weeks and more of gestation leads to an increase in half-life and the mean residence time (MRT) in the second group (33 and 29% respectively). The volume of distribution was unchanged in the two groups. No accumulation of the drug was observed in pregnant women. Pharmacokinetic disorders are correlated with the term and moreover with the weight deviation of women, i.e. the growth of the fetus. These findings suggest accumulation of the aminoglycoside antibiotic in the fetus. Moreover, the efficacy and the safety of this therapeutic regimen were excellent. To limit the potential nephrotoxicity and ototoxicity of tobramycin for the mother and the fetus, a once-daily dose regimen seems to be acceptable for the treatment of non-neutropenic pregnant women.

Mammalian cell lines can be efficiently established in vitro upon expression of the SV40 large T antigen driven by a promoter sequence derived from the human vimentin gene

The aim of this study was to investigate a new method to enhance the efficiency to create mammalian cell lines. Cell immortalization was achieved by intranuclear microinjection of a recombinant DNA construct composed of a constitutive promoter controlling the genes encoding immortalizing proteins; the sequences coding for the large T and small t antigens were fused downstream of regulatory elements from the vimentin gene, the activation of which characterizes the vast majority of cells growing in vitro. Data show that the efficiency of the immortalizing procedures using the SV40 early genes could be enhanced by the control elements derived from the human vimentin (HuVim) 5' sequences that contained nucleotides -878 to +93 from the CAP site. This HuVim 830-T/t recombinant was used to create cell lines from numerous primary cultures of different origins: rabbit, porcine and human endothelial cells, rabbit and bovine epithelial cells. A set of large T-expressing cells was derived, and these cells retained characteristics of differential cells: binding of Ulex europaeus lectin and synthesis of Factor VIII for human endothelial cells; network of cytokeratin for bovine oviductal cells and rabbit mammary cells.

Fetal levels of tobramycin following maternal administration

A single dose of tobramycin 2 mg/kg was given intravenously to a woman who presented a 22-week heterotopic pregnancy with both intrauterine and ovarian gestations and two living fetuses. After excision of the adnexum, tobramycin levels were measured in the maternal serum and in the fetal fluids and tissues. Antibiotic levels were especially high in the fetal spleen and kidney.

Xenotropic and amphotropic pseudotyped recombinant retrovirus to transfer genes into cells from various species

The ability to transfer genes into cells from different species with murine recombinant retroviruses was evaluated with the SVnls LacZ reporter gene. Mouse and cat packaging cell lines can be used to transfer amphotropic pseudotype, in human, mouse, cat, rabbit, sheep, horse and beef cells and with a very low efficiency in pig and avian cells. Xenotropic pseudotype recombinant retroviruses, produced in cat and rabbit packaging cell lines, transferred genes with the same efficiency as amphotropic retroviruses in human, cat, rabbit and sheep cells. In contrast to amphotropic retroviruses, xenotropic retroviruses infect beef, pig and horse cells with a high efficiency. These results emphasize the need to determine carefully the producer cell line (the type of helper virus and the species origin of the cell) for efficient transfer of genes in cells and embryos.

Evolution of prolactin and placental lactogen receptors in ewes during pregnancy and lactation

The present paper describes a method of membrane preparation from ewe mammary gland using a sucrose cushion (1.3 M) to select smooth membranes; this results in a membrane preparation richer in PRL receptors than the microsomal preparation classically used. This method was used for the characterization and measurement of PRL and ovine placental lactogen (oPL) receptors in three organs of the ewe (mammary gland, liver, and adipose tissue). PRL receptors were measured by competition of iodinated human GH ([125I]hGH) with ovine PRL (oPRL). This hormone, which has both growth and lactogenic activities, appears to interact with PRL receptors with a higher affinity than oPRL itself and is a good probe for the determination of PRL receptors in the ewe. oPL receptors were measured by the specific binding of [125I]oPL. This hormone appears to bind exclusively to a somatogenic site in the ewe, since various GHs compete efficiently for binding, whereas oPRL is without effect. The evolution of PRL and oPL receptors was determined during pregnancy and lactation and at different periods after an estradiol and progesterone treatment, which provokes growth of the mammary gland and milk secretion. During pregnancy, PRL receptors increased in the mammary gland up to day 100. During the last trimester, receptor content remained stable, and a second increase occurred during early lactation. No additional significant changes were observed either for PRL receptors in liver or adipose tissue or for oPL receptors in any of the organs studied (mammary gland, liver, adipose tissue). Injections of large doses of estradiol and progesterone to nonpregnant ewes were able to reproduce effectively the pattern of PRL receptors observed during pregnancy, but had no effect on oPL receptor levels. These studies demonstrate the independence of PRL and PL receptor sites in the ewe and suggest a different hormonal regulation for each type of receptor.

Mammary metabolism in the goat during normal or hormonally-induced lactation

Mammary metabolism was studied in 4 normal lactating goats (group N) and in 4 non-pregnant goats induced to lactate by hormonal treatment (group 1). Tissue was sampled by biopsy after 3, 9 and 18 weeks of lactation. Although milk potential was the same in both groups, group 1 produced 45% less milk than group N. The RNA-DNA ratio, activities of lipoprotein lipase (LPL), glucose-6-phosphate dehydrogenase and acetyl-CoA carboxylase, and the beta-casein % of in vitro protein synthesis were not significantly lower in the 1 than in the N goat mammary tissue. This suggests that differences in mammary cell hyperplasia during hormonal treatment, and not potential metabolic activities, partially accounted for the difference in milk yield levels. Milk composition was comparable in the two groups. However, milk fat in group N had a higher long-chain fatty acid content (stearic and oleic acids) during the first month of lactation due to the higher mobilization of body lipids in high-yielding animals. Another qualitative difference was the delayed increase in milk LPL secretion during the first 3 months of lactation in induced goats.

Comparative measurement of the lactogenic activity of ovine placental lactogen in rabbit and ewe mammary gland

Ovine placental lactogen is known to bind to prolactin receptors and to initiate milk synthesis in the rabbit mammary gland. However, this hormone exhibited a very low capacity of competing with 125I-labeled human growth hormone for the binding to membranes extracted from ewe mammary gland. Ovine placental lactogen was very efficient in provoking the accumulation of beta-casein mRNA in rabbit mammary explants but was much less active on ewe mammary explants. These data indicate that the placental hormone is not a potent lactogen in the homologous species and that its role in the control of mammary gland development and activity may have been previously overestimated.

Lactogenesis induced by ovariectomy in pregnant rats and its regulation by oestrogen and progesterone

Ovariectomy on day 19 of pregnancy augmented galactosyl transferase activity 24 h after surgery preceding by 6 h the significant alpha-lactalbumin accumulation. Progesterone, injected immediately after ovariectomy showed a clear inhibitory effect on both galactosyl transferase and alpha-lactalbumin concentration, measured 30 h after ovariectomy. However, once the synthesis of lactose has been induced, progesterone is no longer inhibitory. Oestrogen induced a significant increase in lactose synthetase activity but no effect was obtained on galactosyl transferase activity. Progesterone, in a time and dose dependent relationship, was capable of preventing the effect of estrogen on lactogenesis. The lactogenic action of oestrogen in ovariectomized pregnant rats might be due to a direct effect at the mammary gland level facilitating the action of prolactin or through an indirect effect mediated via an increase on prolactin release.

Hormonal control of casein synthesis in mammary explants from pregnant goats

The effects of insulin, cortisol, prolactin, 3,3',5-triiodo-L-thyronine (L-T3) and progesterone on the synthesis of total protein and casein in mammary explants from pregnant goats were studied. In the absence of hormones and in the presence of insulin plus cortisol the rate of incorporation of 14C-leucine into proteins that were precipitated with the anti-casein antibody decreased during culture. The addition of prolactin to hormonal combination of insulin and cortisol caused large stimulation of rates of casein synthesis. Maximum incorporation of leucine was attained between 3 and 5 days of culture in the presence of 0.5 microgram ml-1 of prolactin. Prolactin stimulated-casein and total protein synthesis were not consistently affected by the addition of L-T3 or progesterone. The inhibition of DNA synthesis by hydroxyurea or cytosine-arabinofuranoside had no effect on casein synthesis in mammary explants from pregnant goats.

Effect of bovine growth hormone on development of goat mammary tissue in organ culture

The effect of bovine growth hormone (bGH) on DNA, protein and casein synthesis in goat mammary explants was studied. Growth hormone was unable to stimulate DNA synthesis or potentiate insulin-stimulated DNA synthesis either in high or low oxygen concentrations. In the presence of insulin and cortisol bGH had no effect on the synthesis of explant cytosol proteins. Two preparations of bGH were tested for their effect on casein synthesis. The preparation NIH-GH-B17 at concentration 50 micrograms ml-1 increased casein synthesis similarly as about 0.5 micrograms ml-1 of prolactin. Our preparation, prepared by the method of Prusík and Braun [1967], at concentration 50 micrograms ml-1 had effect lower than 0.05 micrograms ml-1 of prolactin. The lactogenic activity of NIH-GH-B17 was decreased by treatment with specific antisera to bovine prolactin. When submaximum concentration of prolactin (0.05 microgram ml-1) was added, bGH at concentration as low as 0.5 microgram ml-1 had synergistic effect on prolactin stimulated casein synthesis.

Prolactin receptor turnover in explants of pseudopregnant rabbit mammary gland

Pseudopregnant rabbit mammary glands in organ culture were used to investigate prolactin (PRL) receptor turnover. Chloroquine (100 microM) results in an increase in prolactin receptor levels (15.7 +/- 1.2% to 35.9 +/- 3.5% specific binding), whereas cycloheximide (1 microgram/ml) induces a rapid decline (to 6.4 +/- 1.2%) suggesting a rapid synthesis and degradation of the receptor molecule. Inhibitors of cellular transcription have little effect on receptor levels. Neither actinomycin D nor dichlororibofuranosylbenzimidazole (DRB) diminish PRL receptor levels whereas total protein synthesis is almost completely inhibited, and chloroquine increases the binding even in the presence of transcriptional inhibitors. These results imply that receptor synthesis continues and that the mRNA for the receptor protein is particularly stable. Ouabain (3 micrometers), which blocks the ATP-dependent Na+/K+ pump, provokes a greater than 60% reduction in PRL receptor levels without modifying total protein synthesis. Dinitrophenol (DNP, 1 mM), an oxidative uncoupler, has little effect on receptor levels, possibly due to a blockage of both synthesis and degradation. Prolactin is capable of inducing a 60% down-regulation of its own receptor, and this phenomenon appears to be energy-dependent because it is partially inhibited by DNP. This process seems to involve an increased rate of receptor degradation. These studies suggest that, at any one time, the level of PRL receptors in a target cell is the result of a dynamic equilibrium between receptor synthesis and degradation and that the most frequent modulations occur at the level of translation and lysosomal degradation. In conclusion, in mammary glands of the pseudopregnant rabbit, the prolactin receptor molecule appears to have a short half-life; the mRNA for this protein, however, is relatively stable.

Hormone levels in plasma of ewes induced into lactation

A short-term treatment with estradiol-17 beta and progesterone induced mammary gland growth and lactogenesis in non-pregnant ewes. These events normally occur during the second half of pregnancy. In order to compare the hormonal environment during the treatment to that during pregnancy, the concentrations of total estrogens (TE), progesterone (P4), glucocorticoids (G) and prolactin (Prl) in the plasma were characterized in non-pregnant, intact ewes induced into lactation with subcutaneous injections of estradiol-17 beta (E2-beta) and P4 for 7 consecutive days (days 1 to 7). Eight non-pregnant, intact, multiparous ewes were divided into two groups (groups I and II, 4 ewes each), according to their milk yields recorded during the previous lactation. All the ewes received the short-term treatment with E2-beta and P4; the ewes of group II were also injected with hydrocortisone acetate (H) and growth hormone (GH) twice daily on days 18 to 20. Blood was collected twice daily for 21 days and milking was initiated 19 days after the first injection of E2-beta and P4. Concentrations of TE, P4, G and Prl were measured in the plasma of ewes in group I but only G and Prl were measured in the plasma of the ewes in group II. Two ewes of group I and one of group II failed to lactate. Mean milk yields (2.5 +/- 0.4 and 6.3 +/- 0.9 kg/34 days) were highest when injections of H and GH were included. Average pretreatment concentrations of plasma TE and P4 were 3.1 +/- 0.8 and 2.1 +/- 0.4 ng/ml, respectively; these increased to 10.2 +/- 1.3 and 5.6 +/- 0.6 ng/ml during the week of the E2-beta and P4 injections. Peak concentrations occurred on days 7 and 6, respectively, and the plasma levels had returned to pretreatment values by days 18 to 20. Concentrations of G in plasma were higher (13.0 +/- 1.0 ng/ml) during E2-beta and P4 injections than during pre- or post-injection (7.4 +/- 1.4 and 8.2 +/- 0.7 ng/ml, respectively). Plasma Prl showed biphasic two to six-fold increases on days 4 and 7 during E2-beta and P4 injections and thereafter declined to lower average daily concentrations on days 10 to 13. Plasma Prl began to increase, and its average concentration was 579 +/- 56 ng/ml by days 18 to 20. These results suggest that the amount of the P4 injections should be increased and that the treatment with E2-beta and P4 should last long enough to insure the induction of an endocrine balance which would correspond more accurately to the hormonal events occurring during the second half of pregnancy in the ewe.

Effects of insulin, cortisol and prolactin on lipid, protein and casein syntheses in goat mammary tissue in organ culture

The actions of insulin, prolactin and cortisol on protein, lipid and casein syntheses were examined in goat mammary explants in culture. The synthesis of the three products was stimulated by insulin and prolactin associated or not with cortisol. Casein synthesis was stimulated only when prolactin was present in the culture medium. Prolactin alone was able to significantly support the induction of casein synthesis. After preculture in the presence of insulin alone, the tissue lost part of its capacity to respond to the prolactin stimulus but, when precultured in the presence of insulin + cortisol, it retained its total sensitivity. These data suggest that insulin, prolactin and cortisol are involved in the maintenance of goat mammary tissue in culture but that prolactin essentially stimulates milk synthesis.

Effects of various hormone treatments on induction of lactation in the ewe

In Exp. I and II, 52 of 68 ewes were induced into lactation with twice-daily injections of estradiol-17 beta (E2-beta) and progesterone (P4; .5 and 1.25 mg/kg body weight/day) for 7 days. Additional treatments were twice-daily injections (days 18 to 20) of hydrocortisone, growth hormone, thyroxine and thyrotropin releasing hormone alone or in various combinations. In Exp. III, 12 ewes were induced into lactation. In this experiment, all ewes were injected with E2-beta and hydrocortisone, as previously, but four ewes (III-2) had P4 injections extended to day 20, and four ewes (III-3) were not injected with P4. Across experiments, lowest milk yields during lactation and the lowest percentage of ewes induced into lactation (58%) occurred when only E2-beta and P4 were injected. Inclusion of hydrocortisone injections (50 mg/day) induced the highest percentage of ewes into lactation (86%, 38 of 44), the highest peak daily yields of milk and the highest total yields during lactation. Including injections of growth hormone, thyroxine or thyrotropin releasing hormone alone or in combinations did not produce better results than injections of E2-beta and P4 alone. Injections of E2-beta and hydrocortisone without concurrent injections of P4 were less effective. Intramuscular injections of P4 (10 mg/day) from days 8 to 20 did not inhibit lactogenesis or subsequent lactation. Across all experiments, 76% of multiparous (52/68) and 50% of nulliparous (6/12) ewes produced greater than 100 ml milk/day during their lactation (34 to 95 days). However, yields of milk for ewes that lactated were only 25 to 50% of those from postpartum ewes. The importance of including injections of hydrocortisone in the induction procedure was established, but determination of optimum time to inject and potential importance of other hormones requires additional research.

Stimulation of milk synthesis in the rabbit by fish pituitary extract

The lactogenic properties of extracts of the pituitary glands of salmon and trout were evaluated by using the organ culture technique with rabbit mammary explants. Crude extracts and fractions obtained after chromatography on Ultrogel and selected for their capacity to compete with ovine prolactin in a rabbit mammary gland radioreceptor assay were added to the culture medium. The criteria of lactogenesis were lactose synthetase activity, casein synthesis, measurements of the concentration of casein messenger RNA and the histology of mammary glands. All these tests led to the conclusion that salmon and trout pituitary glands contain a prolactin-like principle capable of initiating milk synthesis in the rabbit mammary cell.

Role of spermidine in casein gene expression in the rabbit

Spermidine concentration in rabbit mammary gland was estimated during pregnancy, lactation and after the induction of milk synthesis by prolactin and glucocorticoids in vivo and in vitro. It was observed that mammogenesis and lactogenesis during preganancy and the initiation of milk secretion at parturition are accompanied by an enhancement of spermidine concentration in the mammary gland. By contrast, the initiation of these phenomena by hormone injections does not require such variations of spermidine concentration. In organ culture, a slight increase in spermidine concentration was obtained under the influence of an hormonal combination including insulin, prolactin and cortisol. Spermidine added to the culture medium was unable to mimic cortisol action. An amplification of casein synthesis and a parallel increase of casein mRNA concentration was provoked by cortisol even when spermidine synthesis was blocked. Thus, one of the major actions of glucocorticoids during lactogenesis in the rabbit is not mediated through an increase in spermidine concentration in the mammary gland.

Stabilization of casein mRNA by prolactin and glucocorticoids

Prolactin injected into pseudopregnant rabbits led to a parallel enhancement of casein synthesis and casein mRNA concentration. When this stimulation was followed by a withdrawal of prolactin obtained by injections of bromocriptine, the rate of casein synthesis progressively diminished. In the presence of endogenous prolactin after the initial stimulation, the decline of casein synthesis was delayed. Hydrocortisone acetate injected with bromocriptine after the initial stimulation by prolactin was able to maintain a high rate of casein synthesis. Measurements of casein mRNA concentration by hybridization with casein cDNA indicated that in all cases the amount of casein mRNA was correlated with the magnitude of casein synthesis. This suggests that the lactogenic hormones, prolactin and glucocorticoids, which were previously demonstrated to be responsible for the enhancement of casein mRNA concentration are involved in their stabilization.

Role of prolactin and glucocorticoids in the expression of casein genes in rabbit mammary gland organ culture. Quantification of casein mRNA

Milk synthesis is initiated solely by prolactin in the pseudopregnant rabbit and glucocorticoids potentiate this action of prolactin. In organ culture, prolactin, in the presence or in the absence of insulin, enhances casein synthesis and cortisol (inactive alone) amplifies this action. Measurements of casein mRNA concentration in total cellular RNA, by hybridization with DNA complementary to casein mRNA, revealed that the stimulation of casein synthesis by the glucocorticoid is accompanied by an increase in the amount of casein mRNA. A systematic comparison of variations of these two parameters indicated that the major effect of glucocorticoids on lactogenesis in the rabbit at this stage of mammary gland development is mediated through an increase in the quantity of casein mRNA available for translation. No simultaneous control of casein mRNA translation by cortisol was observed.

[Relationship between estrogens during gestation, birth weight, and later growth in Charolaise calves]

In Charolais breed linear relationships were found between the oestrogen level in plasma of cows at 220 days of pregnancy and the birth weight (r = .84) and the daily gain of weight from 1-180 days (r=.87).