On understanding proton transfer to the biocatalytic [Fe-Fe](H) sub-cluster in [Fe-Fe]H(2)ases: QM/MM MD simulations.

Proton transfer to the [Fe-Fe](H) sub-cluster in the Desulfovibrio desulfuricans (DdH) and Clostridium pasteurianum (CpI) [Fe-Fe] hydrogenases was investigated by a combination of first principles and empirical molecular dynamics simulations. Pathways that can be inferred from the X-ray crystal structures of DdH and CpI, i.e., (Glu159→Ser198→Glu156→water460→Cys178→DTMA([Fe-Fe](H)) and (Glu282→Ser319→Glu279→water612→Cys299), respectively, were considered. Proton transfer from Cys178 to DTMA in the [Fe-Fe](H) sub-cluster in DdH was readily observed in our results, specifically when [Fe-Fe](H) was in the reduced state ([Fe(I)-Fe(I)]) or in the mixed valence state for the protonated distal iron Fe(d) ([Fe(I)-Fe(II)-H(-)](H)). A concerted mechanism is proposed, where proton transfer in DdH from Glu159 to Glu156 via Ser198 and Glu156 to Cys178 via water460 readily occurred, as well as from Glu282 to Glu279 via Ser319 and Glu279 to Cys299 via water612 in CpI. The theoretical prediction of the proton transfer characteristics is consistent with the assumed biocatalytic mechanism of the [Fe-Fe] hydrogenases in which the proton binds at Fe(d), providing confirmation that has not been explored so far. The computational results were qualitatively validated by the agreement with experimental hydrogen production activity data for mutated CpI enzymes, relative to the wild-type protein. Finally, the insight provided by the simulations, combined, in part, with experimental validation, are important for establishing an approach in future exploration of proton transfer to the active site in this class of enzymes, and possibly also for biomimetic analogs.

Vaginal repair with mesh versus colporrhaphy for prolapse: a randomised controlled trial.

OBJECTIVE: To compare vaginal repair augmented by mesh with traditional colporrhaphy for the treatment of pelvic organ prolapse. DESIGN: Prospective randomised controlled trial. SETTING: Tertiary teaching hospital. POPULATION: One hundred and thirty-nine women with stage >or=2 prolapse according to the pelvic organ prolapse quantification (POP-Q) system requiring both anterior and posterior compartment repair. METHODS: Subjects were randomised to anterior and posterior vaginal repair with mesh augmentation (mesh group, n = 69) or traditional anterior and posterior colporrhaphy (no mesh group, n = 70). MAIN OUTCOME MEASURES: The primary outcome was the absence of POP-Q stage >or=2 prolapse at 12 months. Secondary outcomes were symptoms, quality-of-life outcomes and satisfaction with surgery. Complications were also reported. RESULTS: For subjects attending the 12-month review, success in the mesh group was 81.0% (51 of 63 subjects) compared with 65.6% (40/61) in the no mesh group and was not significantly different (P-value = 0.07). A high level of satisfaction with surgery and improvements in symptoms and quality-of-life data were observed at 12 months compared to baseline in both groups, but there was no significant difference in these outcomes between the two groups. Vaginal mesh exposure occurred in four women in the mesh group (5.6%). De novo dyspareunia was reported by five of 30 (16.7%) sexually active women in the mesh group and five of 33 (15.2%) in the no mesh group at 12 months. CONCLUSION: In this study, vaginal surgery augmented by mesh did not result in significantly less recurrent prolapse than traditional colporrhaphy 12 months following surgery.

Vaginal surgery for pelvic organ prolapse using mesh and a vaginal support device.

OBJECTIVES: To describe a new surgical procedure for pelvic organ prolapse using mesh and a vaginal support device (VSD) and to report the results of surgery. DESIGN: A prospective observational study. SETTING: Two tertiary referral Urogynaecology practices. POPULATION: Ninety-five women with International Continence Society pelvic organ prolapse quantification stage 2 or more pelvic organ prolapse who underwent vaginal surgery using mesh augmentation and a VSD. METHODS: Surgery involved a vaginal approach with mesh reinforcement and placement of a VSD for 4 weeks. At 6 and 12 months, women were examined for prolapse recurrence, and visual analogue scales for satisfaction were completed. Women completed quality-of-life (QOL) questionnaires preoperatively and at 6 and 12 months. MAIN OUTCOME MEASURES: Objective success of surgery at 6 and 12 months following surgery. Secondary outcomes were subjective success, complications, QOL outcomes and patients' satisfaction. RESULTS: Objective success rate was 92 and 85% at 6 and 12 months, respectively. Subjective success rate was 91 and 87% at 6 and 12 months, respectively. New prolapse in nonrepaired compartments accounted for 7 of 12 (58%) failures at 12 months. Two of 4 mesh exposures required surgery. Sexual dysfunction was reported by 58% of sexually active women preoperatively and 23% at 12 months. QOL scores significantly improved at 12 months compared with baseline (P < 0.0001). CONCLUSION: Vaginal surgery using mesh and a VSD is an effective procedure for pelvic organ prolapse. However, further studies are required to establish the role of the surgery described in this study.

Clinical and quality-of-life outcomes in women treated by the TVT-O procedure.

OBJECTIVES: To objectively assess the success rate at 6 months after tension-free vaginal tape obturator (TVT-O) procedure. To assess subjective success rates, complications, patient satisfaction, and quality of life (QOL). DESIGN: A prospective observational study. SETTING: A tertiary referral urogynaecology practice. POPULATION: A cohort of 100 consecutive women who underwent the TVT-O procedure between March and October 2004. METHODS: The TVT-O technique was performed as described. Three standardised QOL questionnaires were completed preoperatively at 6 months and 12 months. At 6 months, a urogenital history, visual analogue scale score (VAS) for patient satisfaction, uroflow, and urinary stress test were performed. After 12 months, a urogenital history and patient satisfaction verbal analogue score (VeAS) were obtained by telephone interview. MAIN OUTCOME MEASURE: Objective success rate of the TVT-O procedure was measured by negative stress test. Secondary outcomes were subjective success rates at 6 and 12 months, pre- and postoperative comparison of urodynamic parameters, complications, postoperative symptomatology, QOL analysis, and patient satisfaction. RESULTS: Mean follow up was 18.5 months. Objective success rate was 95%. Subjective success rates were 92 and 84% at 6 and 12 months. Complications included recurrent urinary tract infection (six), voiding difficulty (two), persistent groin discomfort (three), haematoma (one), wound infection (one), vaginal tape erosion (one), and urethral irritation (one). Prevalence of de novo urge incontinence was 4.1 and 4.8% at 6 and 12 months. QOL analysis showed significant improvements in QOL scores postoperatively. Visual and verbal analogue scores indicated high patient satisfaction (VAS, VeAS >or= 80%) in 77 and 67% at 6 and 12 months. CONCLUSION: The TVT-O is a safe and effective treatment for female stress urinary incontinence.

Laparoscopic versus open Burch colposuspension: a randomised controlled trial.

OBJECTIVE: To compare perioperative characteristics, short-term, and long-term outcomes for laparoscopic Burch colposuspension (LBC) and open Burch colposuspension (OBC) for the treatment of urinary stress incontinence. DESIGN: Randomised surgical trial with single blinding. SETTING: Three tertiary level teaching hospitals involving seven surgeons of varying skill levels. POPULATION: Two hundred women with urodynamic stress incontinence (USI). METHODS: The two groups were treated in identical fashion, except for the laparoscopic or open approach to surgery. Attempts were made to blind the subjects and the observers obtaining outcome data to treatment group. Analyses were adjusted for surgeon experience. MAIN OUTCOME MEASURES: Absence of USI 6 months following surgery, postoperative pain, time spent in hospital, and time to return to activities of normal daily living. RESULTS: There were no significant differences in objective and subjective measures of cure and in patient satisfaction at 6 months, 24 months, or 3-5 years of follow up between laparoscopic and open colposuspension groups. Laparoscopic colposuspension took longer time to perform (87 versus 42 minutes, P< 0.0001) but was associated with less blood loss (P = 0.03), less pain (P = 0.02), and quicker return to normal activities (P = 0.01). CONCLUSION: LBC has significant advantages over traditional OBC, without any apparent compromise in short-term and long-term outcomes. To compare perioperative characteristics, short-term, and long-term outcomes for laparoscopic Burch colposuspension (LBC) and open Burch colposuspension (OBC) for the treatment of urinary stress incontinence. Randomised surgical trial with single blinding. Three tertiary level teaching hospitals involving seven surgeons of varying skill levels. Two hundred women with urodynamic stress incontinence (USI). The two groups were treated in identical fashion, except for the laparoscopic or open approach to surgery. Attempts were made to blind the subjects and the observers obtaining outcome data to treatment group. Analyses were adjusted for surgeon experience. Absence of USI 6 months following surgery, postoperative pain, time spent in hospital, and time to return to activities of normal daily living. There were no significant differences in objective and subjective measures of cure and in patient satisfaction at 6 months, 24 months, or 3-5 years of follow up between laparoscopic and open colposuspension groups. Laparoscopic colposuspension took longer time to perform (87 versus 42 minutes, P < 0.0001) but was associated with less blood loss (P= 0.03), less pain (P= 0.02), and quicker return to normal activities (P= 0.01). LBC has significant advantages over traditional OBC, without any apparent compromise in short-term and long-term outcomes.

Probiotic bacteria enhance murine and human intestinal epithelial barrier function.

BACKGROUND & AIMS: The probiotic compound, VSL#3, is efficacious as maintenance therapy in pouchitis and ulcerative colitis. The aim of this study was to determine the efficacy of VSL#3 as a primary therapy in the treatment of colitis in the interleukin (IL)-10 gene-deficient mouse. Mechanisms of action of VSL#3 were investigated in T(84) monolayers. METHODS: IL-10 gene-deficient and control mice received 2.8 x 10(8) colony-forming units per day of VSL#3 for 4 weeks. Colons were removed and analyzed for cytokine production, epithelial barrier function, and inflammation. VSL#3 or conditioned media was applied directly to T(84) monolayers. RESULTS: Treatment of IL-10 gene-deficient mice with VSL#3 resulted in normalization of colonic physiologic function and barrier integrity in conjunction with a reduction in mucosal secretion of tumor necrosis factor alpha and interferon gamma and an improvement in histologic disease. In vitro studies showed that epithelial barrier function and resistance to Salmonella invasion could be enhanced by exposure to a proteinaceous soluble factor secreted by the bacteria found in the VSL#3 compound. CONCLUSIONS: Oral administration of VSL#3 was effective as primary therapy in IL-10 gene-deficient mice, and had a direct effect on epithelial barrier function.

Identification, characterization and leucocyte expression of Siglec-10, a novel human sialic acid-binding receptor.

Here we characterize Siglec-10 as a new member of the Siglec family of sialic acid-binding Ig-like lectins. A full-length cDNA was isolated from a human spleen library and the corresponding gene identified. Siglec-10 is predicted to contain five extracellular Ig-like domains and a cytoplasmic tail containing three putative tyrosine-based signalling motifs. Siglec-10 exhibited a high degree of sequence similarity to CD33-related Siglecs and mapped to the same region, on chromosome 19q13.3. The expressed protein was able to mediate sialic acid-dependent binding to human erythrocytes and soluble sialoglycoconjugates. Using specific antibodies, Siglec-10 was detected on subsets of human leucocytes including eosinophils, monocytes and a minor population of natural killer-like cells. The molecular properties and expression pattern suggest that Siglec-10 may function as an inhibitory receptor within the innate immune system.

Role of molybdate and other transition metals in the accumulation of protochelin by Azotobacter vinelandii.

Both molybdate and iron are metals that are required by the obligately aerobic organism Azotobacter vinelandii to survive in the nutrient-limited conditions of its natural soil environment. Previous studies have shown that a high concentration of molybdate (1 mM) affects the formation of A. vinelandii siderophores such that the tricatecholate protochelin is formed to the exclusion of the other catecholate siderophores, azotochelin and aminochelin. It has been shown previously that molybdate combines readily with catecholates and interferes with siderophore function. In this study, we found that the manner in which each catecholate siderophore interacted with molybdate was consistent with the structure and binding potential of the siderophore. The affinity that each siderophore had for molybdate was high enough that stable molybdo-siderophore complexes were formed but low enough that the complexes were readily destabilized by Fe(3+). Thus, competition between Fe(3+) and molybdate did not appear to be the primary cause of protochelin accumulation; in addition, we determined that protochelin accumulated in the presence of vanadate, tungstate, Zn(2+), and Mn(2+). We found that all five of these metal ions partially inhibited uptake of (55)Fe-protochelin and (55)Fe-azotochelin complexes. Also, each of these metal ions partially inhibited the activity of ferric reductase, an enzyme important in the deferration of ferric siderophores. Our results suggest that protochelin accumulates in the presence of molybdate because protochelin uptake and conversion into its component parts, azotochelin and aminochelin, are inhibited by interference with ferric reductase.

Siglec-8. A novel eosinophil-specific member of the immunoglobulin superfamily.

We describe the characterization of siglec-8, a novel sialic acid-binding immunoglobulin-like lectin that is expressed specifically by eosinophils. A full-length cDNA encoding siglec-8 was isolated from a human eosinophil cDNA library. Siglec-8 is predicted to contain three extracellular immunoglobulin-like domains, a transmembrane region, and a cytoplasmic tail of 47 amino acids. The siglec-8 gene mapped on chromosome 19q13.33-41, closely linked to genes encoding CD33 (siglec-3), siglec-5, siglec-6, and siglec-7. When siglec-8 was expressed on COS cells or as a recombinant protein fused to the Fc region of human IgG(1), it was able to mediate sialic acid-dependent binding to human erythrocytes and to soluble sialoglycoconjugates. Using specific monoclonal antibodies, siglec-8 could be detected only on eosinophils and hence appears to be the first example of an eosinophil-specific transmembrane receptor.

SOCS1 is a critical inhibitor of interferon gamma signaling and prevents the potentially fatal neonatal actions of this cytokine.

Mice lacking suppressor of cytokine signaling-1 (SOCS1) develop a complex fatal neonatal disease. In this study, SOCS1-/- mice were shown to exhibit excessive responses typical of those induced by interferon gamma (IFNgamma), were hyperresponsive to viral infection, and yielded macrophages with an enhanced IFNgamma-dependent capacity to kill L. major parasites. The complex disease in SOCS1-/- mice was prevented by administration of anti-IFNgamma antibodies and did not occur in SOCS1-/- mice also lacking the IFNgamma gene. Although IFNgamma is essential for resistance to a variety of infections, the potential toxic action of IFNgamma, particularly in neonatal mice, appears to require regulation. Our data indicate that SOCS1 is a key modulator of IFNgamma action, allowing the protective effects of this cytokine to occur without the risk of associated pathological responses.

EMS1 gene expression in primary breast cancer: relationship to cyclin D1 and oestrogen receptor expression and patient survival.

The EMS1 and CCND1 genes at chromosome 11q13 are amplified in about 15% of primary breast cancers but appear to confer different phenotypes in ER positive and ER negative tumours. Since there are no published data on EMS1 expression in large series of breast cancers we examined the relationship of EMS1 expression with EMS1 gene copy number and expression of mRNAs for cyclin D1 and ER. In a subset of 129 patients, where matched tumour RNA and DNA was available, EMS1 mRNA overexpression was associated predominantly with gene amplification (P = 0.0061), whereas cyclin D1 mRNA overexpression was not (P = 0.3142). In a more extensive series of 351 breast cancers, there was no correlation between cyclin D1 and EMS1 expression in the EMS1 and cyclin D1 overexpressors (P = 0.3503). Although an association between EMS1 mRNA expression and ER positivity was evident (P = 0.0232), when the samples were divided into quartiles of EMS1 or cyclin D1 mRNA expression, the increase in the proportion of ER positive tumours in the ascending EMS1 mRNA quartiles was not statistically significant (P = 0.0951). In marked contrast there was a significant stepwise increase in ER positivity in ascending quartiles of cyclin D1 mRNA (P = 0.030). A potential explanation for this difference was provided by the observation that in ER positive breast cancer cells oestradiol treatment resulted in increased cyclin D1 gene expression but was without effect on EMS1. The relationship between EMS1 expression and clinical outcome was examined in a subset of 234 patients with median follow-up of 74 months. High EMS1 expression was associated with age > 50 years (P = 0.0001), postmenopausal status (P = 0.0008), lymph node negativity (P = 0.019) and an apparent trend for worse prognosis in the ER negative subgroup. These data demonstrate that overexpression of EMS1 mRNA is largely due to EMS1 gene amplification, is independent of cyclin D1 and ER expression and, in contrast to cyclin D1, is not regulated by oestrogen. Independent overexpression of these genes may confer different phenotypes and disease outcomes in breast cancer as has been inferred from recent studies of EMS1 and CCND1 gene amplification.

Characterization of siglec-5, a novel glycoprotein expressed on myeloid cells related to CD33.

We describe the characterization of siglec-5 (sialic acid-binding Ig-like lectin-5), a novel transmembrane member of the immunoglobulin superfamily, highly related to the myeloid antigen, CD33. A full-length cDNA encoding siglec-5 was isolated from a human activated monocyte cDNA library. Sequencing predicted that siglec-5 contains four extracellular immunoglobulin-like domains, the N-terminal two of which are 57% identical to the corresponding region of CD33. The cytoplasmic tail is also related to that of CD33, containing two tyrosine residues embodied in immunoreceptor tyrosine-based inhibitory motif-like motifs. The siglec-5 gene was shown to map to chromosome 19q13.41-43, closely linked to the CD33 gene. When siglec-5 was expressed on COS cells or as a recombinant protein fused to the Fc region of human IgG1, it was able to mediate sialic acid-dependent binding to human erythrocytes and soluble glycoconjugates, suggesting that it may be involved in cell-cell interactions. By using specific antibodies, siglec-5 was found to have an expression pattern distinct from that of CD33, being present at relatively high levels on neutrophils but absent from leukemic cell lines representing early stages of myelomonocytic differentiation. Western blot analysis of neutrophil lysates indicated that siglec-5 exists as a disulfide-linked dimer of approximately 140 kD.

Combined analysis of studies of the effects of the matrix metalloproteinase inhibitor marimastat on serum tumor markers in advanced cancer: selection of a biologically active and tolerable dose for longer-term studies.

This combined analysis investigated the effect of marimastat, a specific inhibitor of matrix metalloproteinases, on markers of tumor progression measured in patients with advanced cancer. By defining the tolerability and biological activity of the drug, it aimed to establish an appropriate dose range for use in Phase III trials. Patients with advanced, serologically progressive ovarian, prostatic, pancreatic, and colorectal cancer were recruited into six nonrandomized, dose ranging, multicenter clinical trials in North America and Europe. The biological activity of marimastat was assessed by serial measurements of the serum tumor markers carcinoembryonic antigen, CA125, CA19-9, and prostate-specific antigen. Patients were recruited with tumor markers rising by more than 25% averaged over a 4-week screening period. A biological effect was defined as a level of tumor marker at the end of treatment no greater than at study entry; a partial biological effect was defined as a rise in the level of tumor marker over the treatment period of 0-25% per 4 weeks. Pharmacokinetic and safety data were collected and assessed as the studies progressed. All patients were followed up for survival.

Mechanisms of cyclin-dependent kinase inactivation by progestins.

The steroid hormone progesterone regulates proliferation and differentiation in the mammary gland and uterus by cell cycle phase-specific actions. In breast cancer cells the predominant effect of synthetic progestins is long-term growth inhibition and arrest in G1 phase. Progestin-mediated growth arrest of T-47D breast cancer cells was preceded by inhibition of cyclin D1-Cdk4, cyclin D3-Cdk4, and cyclin E-Cdk2 kinase activities in vitro and reduced phosphorylation of pRB and p107. This was accompanied by decreases in the expression of cyclins D1, D3, and E, decreased abundance of cyclin D1- and cyclin D3-Cdk4 complexes, increased association of the cyclin-dependent kinase (CDK) inhibitor p27 with the remaining Cdk4 complexes, and changes in the molecular masses and compositions of cyclin E complexes. In control cells cyclin E eluted from Superdex 200 as two peaks of approximately 120 and approximately 200 kDa, with the 120-kDa peak displaying greater cyclin E-associated kinase activity. Following progestin treatment, almost all of the cyclin E was in the 200-kDa, low-activity form, which was associated with the CDK inhibitors p21 and p27; this change preceded the inhibition of cell cycle progression. These data suggest preferential formation of this higher-molecular-weight, CDK inhibitor-bound form and a reduced number of cyclin E-Cdk2 complexes as mechanisms for the decreased cyclin E-associated kinase activity following progestin treatment. Ectopic expression of cyclin D1 in progestin-inhibited cells led to the reappearance of the 120-kDa active form of cyclin E-Cdk2 preceding the resumption of cell cycle progression. Thus, decreased cyclin expression and consequent increased CDK inhibitor association are likely to mediate the decreases in CDK activity accompanying progestin-mediated growth inhibition.

Results of single and repeat dose studies of the oral matrix metalloproteinase inhibitor marimastat in healthy male volunteers.

AIMS: To assess the tolerability and pharmacokinetic profile of single and repeat doses of the oral matrix metalloproteinase inhibitor marimastat in healthy male volunteers. METHODS: A total of 31 subjects participated in two placebo-controlled, rising-dose studies. The first study assessed the pharmacokinetics and tolerability of single doses of marimastat of 25, 50, 100, 200, 400 and 800 mg. In the second study, continuous dosing over 6.5 days with three incremental dose levels of 50, 100 and 200 mg twice daily was assessed. Full pharmacokinetic profiles were obtained on days 0 and 6, and trough concentrations were measured on all days. For each pharmacokinetic profile in the studies, summary measures including Cmax, tmax, elimination half-life and AUC were calculated. Urinary drug weights were also measured. All adverse events were documented, and haematological and biochemical variables, vital signs and ECGs were monitored throughout the study. RESULTS: Peak plasma concentrations were observed at 1.5-3 h for all subjects at all doses. Peak levels were approximately proportional to dose, as was drug exposure as calculated by AUC. Data from both studies indicate that the terminal elimination half-life is of the order of 8-10 h, and that there is no unexpected drug accumulation. Marimastat was well-tolerated, with adverse effects being mild and occurring with similar frequency to placebo. Small but reversible elevations in liver transaminases were noted with repeat dosing of marimastat, the most significant of these occurring at a dose of 200 mg twice daily. CONCLUSION: Single and repeat oral doses of marimastat in healthy male subjects appear to be well-tolerated. The drug is rapidly absorbed with high peak levels achieved. It has a terminal elimination half-life of 8-10 h which would support twice daily dosing in further clinical trials.

Antiprogestin inhibition of cell cycle progression in T-47D breast cancer cells is accompanied by induction of the cyclin-dependent kinase inhibitor p21.

Progestin antagonists inhibit the proliferation of progesterone receptor-positive cells, including breast cancer cells, by G1 phase-specific actions, but the molecular targets involved are not defined. Reduced phosphorylation of pRB, a substrate for G1 cyclin-dependent kinases (CDKs) in vivo, was apparent after 9 h treatment of T-47D breast cancer cells with the antiprogestins RU 486 or ORG 31710, accompanying changes in S phase fraction. Although the abundance of cyclin D1, Cdk4, and Cdk6 did not decrease cyclin D1-associated kinase activity was reduced by approximately 50% at 9-18 h. Similarly, cyclin E-associated kinase activity decreased by approximately 60% at 12-24 h in the absence of significant changes in the abundance of cyclin E and Cdk2. The CDK inhibitor p21 increased in mRNA and protein abundance and was present at increased levels in cyclin D1 and cyclin E complexes at times when their kinase activity was decreased. Increased p21 protein abundance was observed in another antiprogestin-sensitive cell line, BT 474, but not in two breast cancer cell lines insensitive to antiprogestins. These data suggest increased p21 abundance and concurrent inhibition of CDK activity as a mechanism for antiprogestin induction of growth arrest. Antiprogestin effects on proliferation were markedly reduced after ectopic expression of cyclin D1, indicating that inhibition of cyclin D1 function is a critical element in antiprogestin inhibition of proliferation. However, these data also implicate regulation of cyclin E function in antiprogestin regulation of cell cycle progression.

Haloalkanoate dehalogenase II (DehE) of a Rhizobium sp.--molecular analysis of the gene and formation of carbon monoxide from trihaloacetate by the enzyme.

A 3-kb EcoRI fragment of genomic DNA from a Rhizobium sp. cloned into pUC19 endowed Escherichia coli K-12 with the ability to grow, albeit slowly, with 2-chloropropionic acid as substrate. The construct expressed weakly a gene that encoded a non-stereospecific 2-chloropropionic acid dehalogenase (dehalogenase II; DehE). The dehE gene was not closely linked to the organism's other two dehalogenase genes, dehD and dehL. The derived amino acid sequence of DehE showed little identity with DehD or DehL, but there was significant identity to two other dehalogenases that act non-selectively on 2-chloropropionic acid. The fragment carried a truncated ORF upstream of dehE that was 51% identical to a positively acting regulatory protein, DehR, required for expression of a Pseudomonas putida dehalogenase gene. In its complete form this gene could encode the Rhizobium sp. dehalogenase-regulatory protein. DehE dehalogenated tribromoacetic acid completely, forming stoichiometric amounts of carbon monoxide and carbon dioxide as the other products.

Cyclin D1 and estrogen receptor messenger RNA levels are positively correlated in primary breast cancer.

The CCND1 gene, encoding the cell cycle regulatory protein cyclin D1, maps to chromosome 11q13, a locus that is amplified in about 13% of breast cancers. Because several studies have indicated a relationship between 11q13 amplification and markers of phenotype including estrogen receptor (ER) status, we tested the relationship between CCND1 and ER gene expression in 364 primary breast cancers using Northern blot analysis. Seventy-three % of samples were positive for ER mRNA, and cyclin D1 mRNA levels in the ER-positive group were significantly higher than those in the ER-negative group (P = 0.0001). When the samples were divided into quartiles of cyclin D1 expression, 58% of samples were ER positive in the lowest quartile and 87% in the highest quartile. The tumors expressing the highest levels of cyclin D1 (7%) were all ER positive. Furthermore, ER mRNA levels in the half with lower cyclin D1 mRNA were significantly less than in the half with higher cyclin D1 levels (P = 0.0001). Using simple regression analysis, there was a significant positive correlation between cyclin D1 and ER mRNA levels in the total population (P = 0.0001). This study demonstrates that cyclin D1 mRNA and ER mRNA are positively correlated in primary breast cancer, but the functional relationship between these genes remains to be elucidated.

Cloning, sequencing and expression in Escherichia coli of two Rhizobium sp. genes encoding haloalkanoate dehalogenases of opposite stereospecificity.

A 6.5-kp EcoRI fragment of genomic DNA from a Rhizobium sp. cloned into pUC19 was able to endow Escherichia coli K-12 with the novel ability to grow at the expense of 2-chloropropionic acid. Subcloning showed that this property was a consequence of two dehalogenases encoded on a 2.2-kb PstI fragment. Further subcloning of the PstI fragment led to two constructs that encoded, separately, dehalogenase activity that acted stereospecifically on D-2-chloropropionic acid and L-2-cloropropionic acid, respectively. The genes encoding these two stereospecific dehalogenases have been sequenced and shown to be separated by 177 bp of non-coding DNA. Expression of the dehalogenase genes involved the vector promoter, suggesting that the anticipated Rhizobium sp. regulatory sequences were not functional in E. coli. Comparison of the deduced amino acid sequences of the two dehalogenases (18% identity) indicated with any other 2-chloropropionic acid dehalogenase studied so far.

Expression of the cyclin-dependent kinase inhibitors p16INK4, p15INK4B and p21WAF1/CIP1 in human breast cancer.

Aberrant cyclin expression has been implicated in oncogenesis in a number of human cancers. Since altered function of regulators of cyclin-dependent kinase (CDK) activity other than cyclins, in particular CDK inhibitors, might play a similar role in oncogenesis, we examined the expression and regulation of the CDK inhibitors p16INK4, p15INK4B and p21WAF1/CIP1 in human breast cancer cell lines. Both the INK4 and INK4B genes were homozygously deleted in 3 cell lines, while INK4 alone was deleted in 2 cell lines. A further 2 cell lines displayed loss of an allele at this locus, and in 1 of these the remaining allele contained a mis-sense mutation within the coding region of the p16INK4 protein. The majority of cell lines examined, including 2 normal mammary epithelial cell strains, expressed low levels of INK4 mRNA and low or undetectable levels of INK4B mRNA. However, INK4 mRNA was expressed at high levels in 5 cell lines, and this was associated with deletion or inactivation of the retinoblastoma susceptibility gene product pRB but not with mutation of TP53. No deletions of the WAF1/CIP1 gene were observed, but WAF1/CIP1 mRNA levels were reduced in cell lines with TP53 mutation. Transfection of a p16INK4 expression vector into MDA-MB-231 cells lacking the INK4 gene failed to produce any p16INK4-expressing cell lines, suggesting that such cells were selected against in continuous culture. Despite the frequent deletion of INK4 in breast cancer cell lines, no evidence was obtained for INK4 deletions in DNA from 45 primary breast carcinomas. Thus, homozygous deletion of the INK4 gene appears to be a rare event in primary breast cancer.