RNA recognition by transcriptional antiterminators of the BglG/SacY family: functional and structural comparison of the CAT domain from SacY and LicT

Transcriptional antiterminators of the BglG/SacY family are regulatory proteins that mediate the induction of sugar metabolizing operons in Gram-positive and Gram-negative bacteria. Upon activation, these proteins bind to specific targets in nascent mRNAs, thereby preventing abortive dissociation of the RNA polymerase from the DNA template. We have previously characterized the RNA-binding domain of SacY from Bacillus subtilis and determined its three-dimensional structure by both NMR and crystallography. In the present study, we have characterized the paralogous domain from LicT and we present the first structural comparison between two BglG/SacY family members. Similar to SacY, the RNA-binding activity of LicT is contained within the 56 N-terminal amino acid residue fragment corresponding to the so-called co-antiterminator (CAT) domain. Surface plasmon resonance affinity measurements show that, compared to SacY-CAT, LicT-CAT binds more tightly and more specifically to its cognate RNA target, with a KD value of about 10(-8) M. The crystal structure of LicT-CAT has been determined at 1.8 A resolution and compared to that of SacY-CAT. Both molecules fold as symmetrical dimers, each monomer comprising a four-stranded antiparallel beta-sheet that stacks against the beta-sheet of the other monomer in a very conserved manner. Comparison of the proposed RNA-binding surfaces shows that many of the conserved atoms concentrate in a central region across one face of the CAT dimer, whereas variable elements are mostly found at the edges. Interestingly, the electrostatic potential maps calculated for the two molecules are quite different, except for the core of the RNA-binding site, which appears essentially neutral in both structures.

Determination of buprenorphine and norbuprenorphine in urine and hair by gas chromatography-mass spectrometry

Buprenorphine, which is used in France as a substitution drug for opioid addiction, is widely abused, and several fatal cases have been reported. In order to confirm a recent intoxication or to establish retrospectively chronic abuse, a simple and reliable gas chromatographic-mass spectrometric method was developed and validated for quantitation of buprenorphine and its active metabolite norbuprenorphine in urine and hair. Two milliliters of urine or 50 mg of pulverized hair was submitted to a pretreatment (enzymatic hydrolysis for urine and decontamination with dichloromethane followed by incubation in 0.1 M HCI for hair). Buprenorphine-d4 was chosen as the internal standard. Selective solid-phase extraction with Bond Elut Certify columns provided recoveries higher than 85% for urine and 43% for hair. By using a mixture of MSTFA/TMSIM/TMCS (100:2:5), buprenorphine and norbuprenorphine produced stable silylated derivatives. The detection was carried out with a quadrupole mass detector working in El selected ion monitoring mode. Ions at m/z 450 and 468 were chosen for the quantitation of buprenorphine and norbuprenorphine, respectively (m/z 454 was used for the internal standard). Limits of quantitation were 0.25 and 0.20 ng/mL, respectively, for buprenorphine and norbuprenorphine in urine and 0.005 ng/mg for the two compounds in hair. Calibration curves were linear from 0 to 50 ng/mL in urine and from 0 to 0.4 ng/mg in hair. Between-day and within-day precisions were less than 8.4% in hair and 6.1% in urine for both molecules in all cases. This method was applied to urine and hair samples collected from patients in a withdrawal treatment program and demonstrated its good applicability in routine analysis and its benefit for clinicians. This technique, which requires instruments already available to many toxicology laboratories, offers an attractive alternative to more sophisticated techniques.

[Evaluation of a series of 137 carcinomas of the endometrium of stage I TNM/UICC]

PURPOSE

To assess retrospectively the long-term results of the combination of surgery and radiotherapy in carcinoma classified cT1.

PATIENTS AND METHODS

From 1974 to 1993, 137 women suffering from endometrial carcinoma cT1Nx-0 M0 were entered into the study. The median age was 62 years (range: 39-85 years) and the median follow up was 67 months (range: 0-224 months).

RESULTS

Surgery was performal in 132 women (96.35%). For cT1, the 5-year overall and specific survivals were 81.1% and 84.5%, respectively. The 10-year overall and specific survivals were 68.8% and 82.2%, respectively. Concerning cT1pT1, the 5-year overall and specific survivals, were 83.9% and 87.4%. The 10-year overall and specific survivals were 71.1% and 85%, respectively. Histological grade, pelvic lymph node involvement and myometrial infiltration influence significantly the overall and specific survivals of cT1pT1 tumors. According to multivariate analysis, pelvic lymph node involvement was a powerful prognostic factor for both the overall and specific survivals. If we rule out pelvic lymph node involvement, WHO histological grade was a significant prognostic factor.

CONCLUSION

Combination of surgery and radiotherapy is still a common procedure for cT1 tumors. When surgery is done before radiotherapy, tailored irradiation may further take place, according to WHO histological grade and pelvic lymph node status.

[Simplified electroretinography protocol and diagnosis of retinal dystrophies in children]

PURPOSE

To report results of a simplified electroretinogram in children.

PATIENTS

124 children under 6 years of age with nystagmus, blindness, neurological disease, cone rod dystrophy in the family, or abnormal fundus appearance were examined.

METHOD

The electroretinogram was recorded by corneal electrodes in an awake state without sedation. A light-emitting orange diode stimulator was used. Stimulation was performed subsequently after 3 minutes of light adaptation and after 8 minutes of darkness. If the electroretinogram was abnormal, a second recording was done a few weeks later using the same method. In some cases, the children were re-examined, and a ganzfeld stimulation ERG was recorded.

RESULTS AND DISCUSSION

This method allowed a reliable diagnosis of photoreceptor dystrophy: Leber's congenital amaurosis with or without rare metabolic diseases, X link pigmentary retinopathy or retinal dystrophy with general disease in children. It helped to differentiate isolated retinal pigment changes with normal electroretinogram from functional retinal impairment and rod-cone dystrophy from other retinal dystrophies.

Thioridazine lengthens repolarization of cardiac ventricular myocytes by blocking the delayed rectifier potassium current

Proarrhythmia has been observed with the antipsychotic agent thioridazine (THIO). The mechanisms underlying these effects are unknown. The objectives of this study were 1) to characterize the effects of THIO on cardiac repolarization and 2) to determine whether lengthening of the Q-T interval could be explained by blocking major K+-repolarizing currents. Isolated, buffer-perfused guinea pig hearts (n = 32) were stimulated at various pacing cycle lengths (150-250 ms) and exposed to THIO at concentrations ranging from 300 nM to 3 microM. THIO increased monophasic action potential duration at 90% repolarization (MAPD90) in a concentration-dependent manner from 14.9 +/- 1.8 at 300 nM to 37.1 +/- 3.2 ms at 3 microM. Increase in MAPD90 was also reverse frequency-dependent; THIO (300 nM) increased MAPD90 by 14.9 +/- 1.8 ms at a pacing cycle length of 250 ms, but by only 7.7 +/- 1.2 ms at a pacing cycle length of 150 ms. Patch-clamp experiments demonstrated that THIO decreases the time-dependent outward K+ current elicited by short depolarizations (250 ms; IK250) in a concentration-dependent manner. Estimated IC50 for IK250, which mostly underlies IKr, was 1.25 microM. Time-dependent outward K+ current elicited in tsA201 cells expressing high levels of HERG protein was also decreased approximately 50% by 1.25 microM THIO. On the other hand, THIO was less potent (IC50 of 14 microM) to decrease time-dependent K+ current elicited by long pulses (5000 ms; IK5000). Under the latter conditions, IK5000 corresponds mainly to IKs. Thus, these results demonstrate block of K+ currents and lengthening of cardiac repolarization by THIO in a concentration-dependent manner. This may provide an explanation of Q-T prolongation observed in some patients treated with THIO.

cDNA cloning and expression analysis of flounder p53 tumour suppressor gene

The screening of a flounder cDNA library with a rainbow trout p53 probe allowed the isolation of a 2.8-kb fragment homologous to human (50%) and rainbow trout (57%) p53 coding sequences. The fragment contains a single open reading frame coding for a 366-amino acid protein. The predicted amino acid sequence is relatively divergent from other p53 proteins but it displays the main p53 features: five highly conserved domains, an acidic N-terminus, a hydrophilic and charged C-terminus, a penultimate serine residue and a putative nuclear localization signal. Furthermore, conservation of critical amino acids and comparable distribution of charge and hydrophobicity suggest that flounder p53 properties could be similar to those in mammals. Northern blot analysis revealed a single transcript of about 3 kb in the flounder ovary tissues. In fact, RT-PCR showed an ubiquitous but very low expression of p53 gene in all flounder tissues.

Production of a polyclonal antibody raised against recombinant flounder p53 protein

The cDNA encoding the wild type p53 protein from flounder, Platichthys flesus, was expressed in Escherichia coli using the GST fusion protein system. Several milligrams of recombinant p53 protein were purified. This protein displayed an apparent molecular weight of 45,000 Da, a value which is very similar to Xenopus p53, but significantly greater than was expected based on the length of the open reading frame. Immunization of rabbits against purified p53 protein allowed the production of high titre polyclonal antiserum. This new polyclonal antibody recognized recombinant flounder p53 protein in Western blot. Cross reaction was also observed with recombinant Xenopus p53 protein but not with human p53 protein. Immunoblotting of the total protein extract from normal flounder ovaries did not reveal any p53 expression.

Comparison of two serological methods and a polymerase chain reaction-enzyme immunoassay for the diagnosis of acute respiratory infections with Chlamydia pneumoniae in adults

Chlamydia pneumoniae is a common respiratory tract pathogen. Serological methods currently used for the diagnosis of C. pneumoniae infection lack specificity, give ambiguous results from a single serum sample and often provide only a retrospective diagnosis. A prospective study was undertaken to assess whether PCR could be a useful addition to the serological techniques routinely practised for diagnosis. This study investigated 68 adult patients with a diagnosis of acute respiratory infection. Acute and convalescent serological determination of antibodies to C. pneumoniae were performed by means of an rELISA test and a micro-immunofluorescence (MIF) test. Nasopharyngeal aspirates or bronchoalveolar lavage specimens and bronchial aspirates obtained from the 68 patients were evaluated by PCR-enzyme immunoassay (PCR-EIA) for the presence of C. pneumoniae and by immunofluorescence assay and cell culture for virus identification. Mycoplasma pneumoniae serology was also performed. Eight patients (11.8%) were positive by either rELISA or PCR-EIA, or both, with an infection rate of 5 (18.5%) of 27 in patients with community-acquired pneumonia, 2 (9%) of 22 in asthmatic patients and 1 (5%) of 19 in patients with an exacerbation of chronic obstructive pulmonary disease. Serological evidence of acute infection was found in four of these patients with the rELISA test and in three others with the MIF test. PCR-EIA detected C. pneumoniae DNA in four specimens, but there were concordant results with both rELISA and PCR-EIA in only one patient A positive PCR-EIA was also obtained in a patient who did not show an antibody response in acute serum. The discrepancy between serological and PCR-EIA results reflects the difficulties in routine laboratory diagnosis of C. pneumoniae infection and the necessity for further studies with optimised techniques.

hSmad5 gene, a human hSmad family member: its full length cDNA, genomic structure, promoter region and mutation analysis in human tumors

hSmad (mothers against decapentaplegic)-related proteins are important messengers within the Transforming Growth Factor-beta1 (TGF-beta1) superfamily signal transduction pathways. To further characterize a member of this family, we obtained a full length cDNA of the human hSmad5 (hSmad5) gene by rapid amplification of cDNA ends (RACE) and then determined the genomic structure of the gene. There are eight exons and two alternative transcripts; the shorter transcript lacks exon 2. We identified the hSmad5 promoter region from a human genomic YAC clone by obtaining the nucleotide sequence extending 1235 base pairs upstream of the 5' end of the cDNA. We found a CpG island consistent with a promoter region, and we demonstrated promoter activity in a 1232 bp fragment located upstream of the transcription initiation site. To investigate the frequency of somatic hSmad5 mutations in human cancers, we designed intron-based primers to examine coding regions by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis. Neither homozygous deletions or point mutations were found in 40 primary gastric tumors and 51 cell lines derived from diverse types of human cancer including 20 cell lines resistant to the growth inhibitory effects of TGF-beta1. These results suggest that the hSmad5 gene is not commonly mutated and that other genetic alterations mediate the loss of TGF-beta1 responsiveness in human cancers.

Two cases of ras mutation associated with liver hyperplasia in dragonets (Callionymus lyra) exposed to polychlorinated biphenyls and polycyclic aromatic hydrocarbons

ras gene activation in a naturally exposed feral fish population may prove to be a particularly sensitive genetic marker of malignancy. The aim of this study was to relate our current knowledge of polychlorinated biphenyl (PCB) bioactivation and polycyclic aromatic hydrocarbon (PAH)-induced DNA damage to ras gene activation in liver tumors from dragonets exposed to these environmental carcinogens. We identified a member of the ras gene family in the marine fish dragonet (Callionymus lyra). The first two exons of this new sequence showed a very high degree of homology with the human ras genes (81-86%) at the nucleic acid level and perfect homology at the amino-acid level. In a pilot study, we collected dragonets from the Seine estuary, an area highly contaminated with PAHs and PCBs. An increase in DNA adducts and an accumulation of ortho- and non-ortho-substituted chlorobiphenyls (CB-77, CB-126, and CB-169) were observed in the livers, a finding that correlates well with the levels of PAHs and PCBs in the sediment. Although liver neoplasia was uncommon, a codon 11 mutation was found in two fish with liver cell hyperplasia, suggesting a possible correlation between hepatic precancerous lesions and ras gene activation in dragonets.

[Relationships between p53 induction, cell cycle arrest and survival of normal human fibroblasts following DNA damage]

It is now well established that in response to genotoxic stresses mammalian cells show an increased p53 protein levels and undergo cell cycle arrest at G1/S and G2/M checkpoints. But, the consequences of these cell cycle arrests on cell survival are not yet elucidated. In this study, we have analysed the relationships between p53 protein induction, cell cycle arrest and cell survival following exposure of normal human fibroblasts (NHFs) to various genotoxic agents such as cisplatin, UV radiation and gamma radiation. p53 protein accumulation and G2/M arrest arose at the same time following exposure to DNA damaging agents, suggesting that p53 is responsible for the G2/M block. However, following inhibition of p53 induction by an antisense oligonucleotide, this G2/M arrest is even more important and correlates with an enhanced sensitivity of NHFs to UV radiation. In addition, there appears to be a threshold in the response of NHFs to DNA damaging agents, p53 induction and cell cycle arrest being observed only with lethal UV doses. We show that: 1) there appears to be a threshold in the cellular response to genotoxic agents, below which neither p53 induction, nor cell cycle arrest, nor cell survival alteration occur and beyond which p53 induction is accompanied by cell cycle arrest and decreased cell survival; 2) although there is a tight temporal relationship, the onset of which depends of the DNA damaging agent used, between the start of p53 induction and the occurrence of G2/M arrest, this latter is independent of p53; 3) p53 inhibition enhances NHFs' sensitivity to DNA damaging agents, the extent of the G2/M arrest correlating with decreased cell survival. Finally, the lack of obligatory correlation between p53 inactivation, apoptosis and radio- or chemoresistance is discussed.

[Pheochromocytoma mimicking septic shock]

A tumour arising from chromaffin cells, the pheochromocytoma may be associated or present with hypotension and result in a lethal shock. The authors report a rare case of pheochromocytoma simulating septic shock. They review the mechanisms by which hypersecretion of catecholamines may cause shock. The detection of pheochromocytoma in its atypical presentation is essential for early diagnosis and the reduction of mortality related to this condition.

[Combination of induction chemotherapy with surgery and/or radiotherapy in locally advanced head and neck cancers. A retrospective analysis of a series of 125 patients]

The prognosis of locally advanced cancers of the head and the neck is pejorative, particularly when nodal involvement is present. In order to improve local control and to reduce distant failures, we have treated stages III and IV patients with induction chemotherapy. From May 1986 to November 1992, 125 patients with squamous cell carcinoma of the head and neck were treated by induction chemotherapy: cisplatine (100 mg/m2 at J1) and 5FU (1 g/m2 from J1 to J5 in continuous infusion) every 21 days subsequent local therapy consisted of surgery for patients with resectable disease, and/or radiotherapy. One hundred and nineteen patients were assessable (110 men and 9 women) with a median age of 57 years (range: 36-78). All patients had performance status inferior or equal to 2. According to the TNM of UICC classification 50 patients were stage IV (42%), 61 stage III (51%), 7 stage II (6%) and a stage I (1%). One hundred (84%) patients have received at least 3 cycles of chemotherapy. Seventy-four patients (62%, IC: 60.4-63.5) had clinical objective response (complete response (CR) or partial response (PR)) with 24 patients (20%) CR and 50 patients (42%) PR. Local therapy included surgery in 81 patients (68%) and radiotherapy alone in 42 patients (35%). Overall, 103 patients (87%) were rendered clinically disease-free by treatment on this protocol. The toxicities of cisplatine and 5-FU chemotherapy consisted predominantly of myelosuppression (5%) and renal toxicities (4%) and were moderate as described for this combination. At a median follow-up of 32 months, the median survival is 38 months (CI 95%, 18-54 months), and the median time to progression is 62 months. The oropharynx localization reached statistical significance for survival rates (Log-rank test, p = 0.02).

Mutation analysis of the transforming growth factor-beta type II receptor in human cell lines resistant to growth inhibition by transforming growth factor-beta

The transforming growth factor-beta (TGF-beta) binds the type II TGF-beta growth factor receptor (RII) to inhibit the growth of most epithelial tissues. Most human colon and gastric cancers with microsatellite instability (MI) have frameshift mutations in polynucleotide repeats within the RII coding region; these mutations truncate the receptor protein and disable the serine/threonine kinase to produce TGF-beta resistance. To further investigate the type, frequency and tissue distribution of RII mutations, we selected 24 human cancer cell lines from various tissues which were previously reported to be resistant to the inhibitory effects of TGF-beta. We developed protocols for non-isotopic SSCP analysis of PCR products from genomic DNA samples, and we tested them for microsatellite instability. PCR-SSCP analysis followed by DNA sequencing identified deletion mutations in the exon 3 poly-adenine tract in three colon tumor cell lines: LS174T and SW48 had a single base deletion and LS411 had a two base deletion. Among the 24 previously unreported cell lines, only these three demonstrated microsatellite instability. These and other recent data indicate that RII mutations are essentially confined to colon and gastric cancers with microsatellite instability. The narrow spectrum of tissues containing RII mutations illustrates the complexity of genetic checkpoints in human carcinogenesis.

Gas chromatographic quantitation of dextropropoxyphene and norpropoxyphene in urine after solid-phase extraction

A gas chromatographic technique with flame ionization detection, which is based on a solid-phase extraction (SPE) procedure using mixed-mode SPE columns, for the simultaneous quantitation of dextropropoxyphene and norpropoxyphene in urine is presented. Urine is treated with sodium hydroxide in order to rearrange, by base catalysis, norpropoxyphene to norpropoxyphene amide, which is then extracted with these columns and chromatographed. The method is specific, linear over the range 0-2000 ng/mL, sensitive, and reproducible. The extracts are cleaner than those obtained with traditional liquid-liquid extraction procedure, which is an important feature in view of further mass spectrometric confirmation of narcotics and other drugs.

Successful treatment of severe hepatic veno-occlusive disease after allogeneic bone marrow transplantation by transjugular intrahepatic portosystemic stent-shunt (TIPS)

Severe veno-occlusive (VOD) disease is a major cause of morbidity and mortality in allogeneic bone marrow transplant recipients, and new approaches in managing patients who develop serious VOD is needed. In this report, we describe a patient who underwent transjugular intrahepatic portosystemic stent-shunt (TIPS) for life-threatening VOD are following allogeneic bone marrow transplantation for AML. Although the patient died of CMV-associated pneumonitis 5 weeks later, the TIPS functioned well until her death and permitted regression of the hepatic and renal symptoms. This report suggests that TIPS may be feasible and effective for managing patients with life-threatening liver dysfunction after marrow transplantation.

Mutation analysis of the transforming growth factor beta type II receptor in sporadic human cancers of the pancreas, liver, and breast

The transforming growth factor beta (TGF beta) binds the type II TGF beta growth factor receptor (TGF beta RII) to inhibit growth of most epithelial tissues. Most human colon cancers with microsatellite instability have frameshift mutations in two microsatellites within the TGF beta RII coding region; such mutations truncate the receptor to produce resistance to TGF beta. To investigate this pathway in other tissues, we surveyed sporadic human cancers of the pancreas, liver and breast to determine the frequency of microsatellite mutations in the TGF beta RII. We amplified genomic DNA segments containing two microsatellites plus 72% of domain XI of the serine-threonine kinase region. SSCP analysis showed no evidence of mutation in 32 sporadic cancers (12 pancreas, 10 liver, and 10 breast). We conclude that microsatellite mutations in TGF beta RII are uncommon in sporadic tumors of the pancreas, liver and breast.

Tumoricidal potential of human macrophages grown in vitro from blood monocytes

Adoptive transfer of activated autologous human macrophages obtained by in vitro differentiation of monocytes in culture has successfully undergone phase I clinical trials in patients with metastatic cancer. The efficacy of these autologous macrophages in the in vivo killing of human tumors has now to be demonstrated. GM-CSF was shown to increase the number of monocytes differentiating in culture into macrophages. These were then activated with IFN gamma which was reported as the best cytokine for tumoricidal activation of macrophages. The aim of this paper was to evaluate the in vitro tumoricidal activity of macrophages grown with GM-CSF and IFN gamma. This tumoricidal function was investigated by measurement of the cytolytic (chromium-51 release assay), cytostatic (anti-proliferative activity as measured by inhibition of [3H]-thymidine incorporation in two different assays) and cytotoxic (MTT assay) activities on two tumor cells lines, U937 and K562 (respectively highly sensitive and resistant to soluble TNF alpha). Our results demonstrated that GM-CSF-grown macrophages exhibited significant cytolytic, cytotoxic and cytostatic activities on U937 cells. These were partly enhanced by IFN gamma activation. In contrast, they had no lytic and lower cytotoxic and cytostatic activities on K562 cells, and these were not modified by IFN gamma activation. Our data provide valuable information for future in vivo studies using adoptively transferred autologous macrophages.