Lignor process for acidic rock drainage treatment

The process using lignosulfonates for acidic rock drainage (ARD) treatment is referred to as the Lignor process. Lignosulfonates are waste by-products produced in the sulfite pulping process. The present study has shown lignosulfonates are able to protect lime from developing an external surface coating, and hence to favor its dissociation. Further, the addition of lignosulfonates to ARD solutions increased the dotting and settling rate of the formed sludge. The capability of lignosulfonates to form stable metal-lignin complexes makes them very useful in retaining metal ions and thus improving the long-term stability of the sludge against leaching. The Lignor process involves metal sorption with lignosulfonates, ARD neutralization by lime to about pH 7, pH adjustment with caustic soda to 9.4 - 9.6, air oxidation to lower the pH to a desired level, and addition of a minimum amount of FeCl3 for further removal of dissolved metals. The Lignor process removes all concerned metals (especially Al and Mn) from the ARD of the Britannia Mine (located at Britannia Beach, British Columbia, Canada) to a level lower than the limits of the B.C. Regulations. Compared with the high-density sludge (HDS) process, the Lignor process has many advantages, such as considerable savings in lime consumption, greatly reduced sludge volume, and improved sludge stability.

Improved survival in steroid-refractory acute graft versus host disease after non-myeloablative allogeneic transplantation using a daclizumab-based strategy with comprehensive infection prophylaxis

Approximately 15% of patients undergoing non-myeloablative allogeneic haematopoietical cell transplantation (NMHCT) develop steroid-refractory acute-graft versus host disease (aGVHD), a usually fatal complication. We encountered 18 cases of steroid-refractory aGVHD in 146 patients, undergoing NMHCT from a related human leucocyte antigen-compatible donor following cyclophosphamide/fludarabine-based conditioning. Our initial cohort of steroid-refractory aGVHD patients treated with antithymocyte globulin (ATG) and mycophenolate mofetil (regimen-1: n = 6) had high GVHD-related mortality. Therefore, we investigated an alternative strategy for subsequent patients developing this complication (regimen-2: n = 12), consisting of daclizumab (alone or combined with infliximab/ATG) and targeted broad spectrum antibacterial and aspergillus prophylaxis in conjunction with rapid tapering of steroids to minimize opportunistic infections. In a retrospective analysis, patients receiving regimen-2 were significantly more likely to have complete resolution of GVHD compared with those receiving regimen-1 [12/12 (100%) vs. 1/6 (17%); P < 0.001]. When compared with those receiving regimen-1, regimen-2 patients also had a higher probability of survival at day 100 (100% vs. 50%) and day 200 (73% vs. 17%) post-transplant, and improved overall survival (median 453 d vs. 42 d from aGVHD onset; P < 0.0001). GVHD-related mortality was 89% for regimen-1 patients vs. 17% for regimen-2 patients (P < 0.0001). These data suggest that a co-ordinated approach using immunoregulatory monoclonal antibodies, pre-emptive antimicrobial therapy and judicious steroid withdrawal can dramatically improve outcome in steroid-refractory aGVHD.

Homozygosity at the MTL locus in clinical strains of Candida albicans: karyotypic rearrangements and tetraploid formation†

One hundred and twenty Candida albicans clinical isolates from the late 1980s and early 1990s were examined for homozygosity at the MTL locus. Of these, 108 were heterozygous (MTLa/MTLalpha), whereas seven were MTLa and five were MTLalpha. Five of the homozygous isolates were able to switch to the opaque cell morphology, while opaque cells were not detectable among the remaining seven. Nevertheless, all but one of the isolates homozygous at the MTL locus were shown to mate and to yield cells containing markers from both parents; the non-mater was found to have a frameshift in the MTLalpha1 gene. In contrast to Saccharomyces cerevisiae, C. albicans homozygotes with no active MTL allele failed to mate rather than mating as a cells. There was no correlation between homozygosity and fluconazole resistance, mating and fluconazole resistance or switching and fluconazole resistance, in part because most of the strains were isolated before the widespread use of this antifungal agent, and only three were in fact drug resistant. Ten of the 12 homozygotes had rearranged karyotypes involving one or more homologue of chromosomes 4, 5, 6 and 7. We suggest that karyotypic rearrangement, drug resistance and homozygosity come about as the result of induction of hyper-recombination during the infection process; hence, they tend to occur together, but each is the independent result of the same event. Furthermore, as clinical strains can mate and form tetraploids, mating and marker exchange are likely to be a significant part of the life cycle of C. albicans in vivo.

Dual Modelling of Permutation and Injection Problems

When writing a constraint program, we have to choose which variables should be the decision variables, and how to represent the constraints on these variables. In many cases, there is considerable choice for the decision variables. Consider, for example, permutation problems in which we have as many values as variables, and each variable takes an unique value. In such problems, we can choose between a primal and a dual viewpoint. In the dual viewpoint, each dual variable represents one of the primal values, whilst each dual value represents one of the primal variables. Alternatively, by means of channelling constraints to link the primal and dual variables, we can have a combined model with both sets of variables. In this paper, we perform an extensive theoretical and empirical study of such primal, dual and combined models for two classes of problems: permutation problems and injection problems. Our results show that it often be advantageous to use multiple viewpoints, and to have constraints which channel between them to maintain consistency. They also illustrate a general methodology for comparing different constraint models.

Application of ferric sludge to immobilize leachable mercury in soils and concrete

A Hg-contaminated site in B.C. Province, Canada was caused by the previous operation of Hg-cell in chlor-alkali process for over 25 years. The soils and groundwater at the site are highly contaminated with mercury. An analysis of groundwater at the site has shown that most of the mercury is bonded with humic and fulvic acids (HFA) in colloidal form. The Hg-HFA colloids can be completely removed from the groundwater with ferric chloride treatment under optimized process conditions to form ferric sludge (FS), which is rendered non-leachable by standard TCLP (Toxicity Characteristic Leaching Procedure) test. The effluent discharged from a clarifier has achieved mercury levels of < 0.5 microkg l(-1). The studies of mercury adsorption characteristics of FS show it has low mercury leachability by TCLP, and great mercury adsorption capability. This feature is the basis for the application of FS to immobilization of leachable Hg-contaminants in solid wastes. Full-scale stabilization tests of Hg-contaminated soil have been carried out, and the time-based stability of the treated soil has been monitored by TCLP over a period of 60 days. All the results have shown a small variation in TCLP mercury levels within a range of 10-40 microg l(-1). Based on these results and with the approval of the B.C. Ministry of the Environment, 1850 tons of Hg-contaminated soils and 260 tons of Hg-contaminated concrete fines have been treated, stabilized with FS, and disposed in a non-hazardous waste disposal site.

A new technology for the treatment of mercury contaminated water and soils

A new technology has been developed for the treatment of contaminated water and soils with lignin derivatives. It has been demonstrated that this technology can be used in the process of removal of high levels of mercury from water, and in the immobilization of leachable mercury in contaminated soils. Lignin derivatives contain an abundance of oxygen-containing functional groups such as phenolic, carboxyl, sulfonyl, alcoholic and enolic structures, which will form lignin-metal macromolecular complexes with high stability through ionic and coordinate covalent bonding. This feature is the basis for the application of lignin derivatives in the removal of metal contaminants from water and in the immobilization of leachable metal in soils or sediments. Tests have confirmed that lignin derivatives are capable of combining with a variety of metal ions including chromium, copper, lead, zinc, mercury, nickel and aluminum. In the new water treatment process, lignin derivatives are dissolved in mercury contaminated water to complex mercury in an exceptionally stable form of a lignin-mercury colloid. The lignin-mercury colloid is then coagulated through the addition of a flocculating agent such as ferric chloride. Under optimized conditions, a dean effluent is produced with a residual mercury level of less than 1 microg l(-1), together with a ferric sludge that is not leachable by TCLP, EPA Method 1311. In the new soil stabilization process, a new solid adsorbent of ferric-lignin is blended with mercury contaminated soil. This solid adsorbent can stabilize the soil by complexing with mercury and, thereby, greatly reduce the TCLP mercury of soil.

Effect of H. pylori infection on the expression of cyclooxygenase-2 in human gastric mucosa

Cyclooxygenase-1 is the primary isoform responsible for the production of cytoprotective prostaglandins (PGE(2) and PGI(2)) in the stomach. In contrast COX-2 is induced at the sites of inflammation. Using Helicobacter pylori infection as a model of inflammation, this study was designed to evaluate the effects of H. pylori infection on prostanoid synthesis and expression of COX-2 in human gastric mucosa. Prostaglandin (PGE(2)) and prostacyclin (PGI(2)) synthesis in gastric biopsies obtained from 21 patients undergoing diagnostic endoscopy, were determined. H. pylori was detected by CLO test, histology and culture. Biopsy samples were incubated either with NS-398, selective COX-2 inhibitor or aspirin. Samples were also treated with endotoxin (LPS) in order to induce COX-2 expression. Tissue was also analysed for COX-2 expression in vivo by immunohistochemistry. In 15 out of 21 patients, H. pylori was detected by at least two of the three methods. Higher levels of PGE(2) and PGI(2) were seen in patients infected with H. pylori (191+/-30 and 245+/-88ng/mg protein, respectively) compared with non-infected patients (77+/-17 and 120+/-36ng/mg protein, respectively). There was significant inhibition of PGE(2) and PGI(2) with aspirin in both H. pylori infected (28+/-6.6 and 53+/-43ng/mg, respectively) and in non-infected patients (16+/-7 and 12.5+/-3.5ng/mg protein, respectively). However, NS-398 and LPS did not alter prostaglandin function significantly. Immunohistochemistry in all patients irrespective of Hp status demonstrated expression of COX-2.Lower concentration of constitutive expression of COX-2 was detected in human gastric mucosa by immunohistochemistry, however, H. pylori infection failed to induce COX-2 protein. In addition, increased prostaglandin synthesis in Hp-infected patients appears to be COX-1 mediated rather than COX-2. Furthermore, failure of endotoxaemia-treated sample to produce more PGE(2) in the face of enhanced COX-2 expression in gastric mucosa further suggests that increased prostanoids in human gastric stomach are COX-1 mediated.

The founder mutation MSH2*1906G-->C is an important cause of hereditary nonpolyposis colorectal cancer in the Ashkenazi Jewish population

Hereditary nonpolyposis colorectal cancer (HNPCC) is caused by mutations in the mismatch-repair genes. We report here the identification and characterization of a founder mutation in MSH2 in the Ashkenazi Jewish population. We identified a nucleotide substitution, MSH2*1906G-->C, which results in a substitution of proline for alanine at codon 636 in the MSH2 protein. This allele was identified in 15 unrelated Ashkenazi Jewish families with HNPCC, most of which meet the Amsterdam criteria. Genotype analysis of 18 polymorphic loci within and flanking MSH2 suggested a single origin for the mutation. All colorectal cancers tested showed microsatellite instability and absence of MSH2 protein, by immunohistochemical analysis. In an analysis of a population-based incident series of 686 Ashkenazi Jews from Israel who have colorectal cancer, we identified 3 (0.44%) mutation carriers. Persons with a family history of colorectal or endometrial cancer were more likely to carry the mutation than were those without such a family history (P=.042), and those with colorectal cancer who carried the mutation were, on average, younger than affected individuals who did not carry it (P=.033). The mutation was not detected in either 566 unaffected Ashkenazi Jews from Israel or 1,022 control individuals from New York. In hospital-based series, the 1906C allele was identified in 5/463 Ashkenazi Jews with colorectal cancer, in 2/197 with endometrial cancer, and in 0/83 with ovarian cancer. When families identified by family history and in case series are included, 25 apparently unrelated Ashkenazi Jewish families have been found to harbor this mutation. Although this pathogenic mutation is not frequent in the Ashkenazi Jewish population (accounting for 2%-3% of colorectal cancer in those whose age at diagnosis is <60 years), it is highly penetrant and accounts for approximately one-third of HNPCC in Ashkenazi Jewish families that fulfill the Amsterdam criteria.

Performance of a hybrid central venous catheter utilized for both peripheral blood stem cell harvest and transplant support of patients undergoing autologous peripheral blood stem cell transplantation

Patients undergoing autologous peripheral blood stem cell transplantation (PBSC) frequently require the sequential insertion of two central venous catheters, one for leukapheresis and one for transplant support. Hybrid catheters suitable for leukapheresis and long-term use have been increasingly used, but there is limited information regarding their performance and complication rate. The purpose of this study was to determine the performance of the Pheres-Flow hybrid catheter when utilized for both leukapheresis and transplant support, with particular emphasis on the incidence of infectious and occlusive complications. We prospectively analyzed the performance of 92 catheters in 82 consecutive patients who underwent autologous peripheral blood stem cell (PBSC) transplantation. Occlusion was the most frequent complication of this catheter with 29% of the patients experiencing difficulty drawing blood or infusing fluids. Infection was another frequent complication. Twenty-two percent of patients developed catheter-related bloodstream infections and 15 catheters had to be removed because of proven or suspected infection that did not respond to antibiotic therapy. Nevertheless, 77% of patients were able to complete leukapheresis and transplant support with only one catheter. We conclude that the utilization of the Pheres-Flow catheter for both leukapheresis and transplant support is feasible, but that new strategies need to be developed to decrease the incidence of occlusive and infectious complications of hybrid catheters.

Human factors error and patient monitoring

A wide range of studies have shown that human factors errors are the major cause of critical incidents that threaten patient safety in the medical environments where patient monitoring takes place, contributing to approximately 87% of all such incidents. Studies have also shown that good cognitively ergonomic design of monitoring equipment for use in these environments should reduce the human factors errors associated with the information they provide. The purpose of this review is to consider the current state of knowledge concerning human factors engineering in its application to patient monitoring. It considers the prevalence of human factors error, principles of good human factors design, the effect of specific design features and the problem of the measurement of the effectiveness of designs in reducing human factors error. The conclusion of the review is that whilst the focus of human factors studies has, in recent years, moved from instrument design to organizational issues, patient monitor designers still have an important contribution to make to improving the safety of the monitored patient. Further, whilst better psychological understanding of the causes of human factors errors will in future guide better human factors engineering, in this area there are still many practical avenues of research that need exploring from the current base of understanding.

Comparison between the Datex-Ohmeda M-COVX metabolic monitor and the Deltatrac II in mechanically ventilated patients

OBJECTIVE

To compare the M-COVX and the Deltatrac II metabolic monitors under clinical conditions.

DESIGN

Prospective clinical comparison.

SETTING

A general Intensive Care Unit of a university hospital.

PATIENTS

Twenty mechanically ventilated critically ill patients.

INTERVENTIONS

The monitors were compared at FiO(2) 0.3, 0.5, and 0.7 in each patient where possible.

MEASUREMENTS AND RESULTS

Pulmonary gas exchange measurements were recorded using the two monitors sequentially (Deltatrac(before), M-COVX, Deltatrac(after)). Each measurement consisted of five consecutive 1-min readings of VO(2) and VCO(2). We compared the Deltatrac(before) with the Deltatrac(after) and the mean of the Deltatrac with the M-COVX. There was no clinically significant bias between the two monitors for VO(2) or VCO(2) but the limits of agreement (LOA) were wide (bias +/-95% LOA: VCO(2) -13 +/- 30 ml/min, -8 +/- 36 ml/min, 7 +/- 50 ml/min; VO(2) -7 +/- 50 ml/min, -5 +/- 56 ml/min, 6 +/- 64 ml/min, at FiO(2) 0.3, 0.5, and 0.7, respectively). The Deltatrac before and after measurements displayed good agreement for VCO(2) but poorer agreement for VO(2) (bias +/- 95% LOA: VCO(2) 0 +/- 18 ml/min, -6 +/- 16 ml/min, -1 +/- 12 ml/min; VO(2) 2 +/- 12 ml/min, 3 +/- 38 ml/min, 10 +/- 42 ml/min, at FiO(2) 0.3, 0.5, and 0.7, respectively). Using within-patient standard deviation as a measure of reproducibility suggested that for VO(2) the M-COVX performed better than the Deltatrac at high FiO(2), and for VCO(2) Deltatrac was better at lower FiO(2).

CONCLUSIONS

The M-COVX is a suitable integrated device for measuring metabolic gas exchange in ventilated patients.

Primary healthcare provider's lost opportunity to help abused women

PURPOSE

To determine how often primary care providers have the opportunity to assess and intervene for intimate partner violence (IPV) in a population of women who are known to be experiencing IPV.

DATA SOURCES

A convenience sample of 149 abused women presenting to the justice system for protection orders or to file assault charges against in intimate partner were interviewed about the date and reason for her last healthcare visit, whether she had been screened for IPV, and the presence of selected conditions, medication use, and hospitalizations.

CONCLUSIONS

Although 86% (n = 128) of the women had sought healthcare services within the previous year, only 24% (n = 36) had been assessed for IPV.

IMPLICATIONS FOR PRACTICE

Abused women use healthcare services at higher rates and have more health conditions than non-abused women. Despite recommendations of professional organizations, health providers have low rates of screening for IPV. Universal screening for IPV by nurse practitioners could substantially interrupt ongoing abuse.

Cellulose sulfate: tolerance and acceptability of penile application

Sodium cellulose sulfate (CS) is under development as a vaginal microbicide and spermicide. This was a Phase I, randomized, double-blind study of men to assess acceptability, safety, and degree of penile irritation of seven consecutive daily doses of CS compared to an active control containing nonoxynol-9 (Conceptrol). The data suggest that CS gel is not more irritating to the male genitalia than Conceptrol. This, along with the minimal irritation seen in a Phase I safety study in women following 6 consecutive days of vaginal administration, suggests that CS could be used in future studies, without undue risk, where couples engage in vaginal intercourse. Male volunteers in future studies should be informed that 1 out of 24 participants in the CS group in this study experienced tingling and slight stinging for a brief time after exposure compared with 3 out of 12 in the Conceptrol group who reported similar symptoms.

Tamoxifen and breast cancer incidence among women with inherited mutations in BRCA1 and BRCA2: National Surgical Adjuvant Breast and Bowel Project (NSABP-P1) Breast Cancer Prevention Trial

CONTEXT

Among cancer-free women aged 35 years or older, tamoxifen reduced the incidence of estrogen receptor (ER)-positive but not ER-negative breast cancer. The effect of tamoxifen on breast cancer incidence among women at extremely high risk due to inherited BRCA1 or BRCA2 mutations is unknown.

OBJECTIVE

To evaluate the effect of tamoxifen on incidence of breast cancer among cancer-free women with inherited BRCA1 or BRCA2 mutations.

DESIGN, SETTING, AND PARTICIPANTS

Genomic analysis of BRCA1 and BRCA2 for 288 women who developed breast cancer after entry into the randomized, double-blind Breast Cancer Prevention Trial of the National Surgical Adjuvant Breast and Bowel Project (between April 1, 1992, and September 30, 1999).

MAIN OUTCOME MEASURE

Among women with BRCA1 or BRCA2 mutations, incidence of breast cancer among those who were receiving tamoxifen vs incidence of breast cancer among those receiving placebo.

RESULTS

Of the 288 breast cancer cases, 19 (6.6%) inherited disease-predisposing BRCA1 or BRCA2 mutations. Of 8 patients with BRCA1 mutations, 5 received tamoxifen and 3 received placebo (risk ratio, 1.67; 95% confidence interval, 0.32-10.70). Of 11 patients with BRCA2 mutations, 3 received tamoxifen and 8 received placebo (risk ratio, 0.38; 95% confidence interval, 0.06-1.56). From 10 studies, including this one, 83% of BRCA1 breast tumors were ER-negative, whereas 76% of BRCA2 breast tumors were ER-positive.

CONCLUSION

Tamoxifen reduced breast cancer incidence among healthy BRCA2 carriers by 62%, similar to the reduction in incidence of ER-positive breast cancer among all women in the Breast Cancer Prevention Trial. In contrast, tamoxifen use beginning at age 35 years or older did not reduce breast cancer incidence among healthy women with inherited BRCA1 mutations. Whether tamoxifen use at a younger age would reduce breast cancer incidence among healthy women with BRCA1 mutations remains unknown.

Kirsten ras mutations in patients with colorectal cancer: the 'RASCAL II' study

Researchers worldwide with information about the Kirsten ras (Ki-ras) tumour genotype and outcome of patients with colorectal cancer were invited to provide that data in a schematized format for inclusion in a collaborative database called RASCAL (The Kirsten ras in-colorectal-cancer collaborative group). Our results from 2721 such patients have been presented previously and for the first time in any common cancer, showed conclusively that different gene mutations have different impacts on outcome, even when the mutations occur at the same site on the genome. To explore the effect of Ki-ras mutations at different stages of colorectal cancer, more patients were recruited to the database, which was reanalysed when information on 4268 patients from 42 centres in 21 countries had been entered. After predetermined exclusion criteria were applied, data on 3439 patients were entered into a multivariate analysis. This found that of the 12 possible mutations on codons 12 and 13 of Kirsten ras, only one mutation on codon 12, glycine to valine, found in 8.6% of all patients, had a statistically significant impact on failure-free survival (P = 0.004, HR 1.3) and overall survival (P = 0.008, HR 1.29). This mutation appeared to have a greater impact on outcome in Dukes' C cancers (failure-free survival, P = 0.008, HR 1.5; overall survival P = 0.02, HR 1.45) than in Dukes' B tumours (failure-free survival, P = 0.46, HR 1.12; overall survival P = 0.36, HR 1.15). Ki-ras mutations may occur early in the development of pre-cancerous adenomas in the colon and rectum. However, this collaborative study suggests that not only is the presence of a codon 12 glycine to valine mutation important for cancer progression but also that it may predispose to more aggressive biological behaviour in patients with advanced colorectal cancer.

Assessing African American adolescents' risk for suicide attempts: attachment theory

The threat of separation from a parent theoretically increases the risk of adolescent suicide attempts. The present study evaluated this and other hypothesized risk factors in a sample of adolescent suicide attempters and nonsuicidal controls, using the Psychiatric Consultation Checklist (Lyon, 1987). Stepwise logistic regression was used to predict group membership. It was found that threat of separation from a parental figure, insomnia, neglect, substance abuse, suicidal ideation, and failing grades were the strongest predictors of suicide attempt. Ten predictor variables correctly identified 97% of suicide attempters and 86% of nonattempters. Unexpected findings included high levels of truancy, threatening others, and separation from a parent before the age of 12 among nonattempters.

Synthetic peptides which inhibit the interaction between C1q and immunoglobulin and prolong xenograft survival

BACKGROUND

Acute vascular xenograft rejection (AVXR), also termed delayed xenograft rejection (DXR), occurs when hyperacute rejection (HAR) is prevented by strategies directed at xenoreactive natural antibodies and/or complement activation. We have hypothesized that AVXR/DXR is initiated in part by early components of the complement cascade, notably C1q. We have developed synthetic peptides (termed CBP2 and WY) that interfere with the interaction between C1q and antibody.

METHODS

CBP2 and the WY-conjugates were used as inhibitors of immunoglobulin aggregate binding to solid phase C1q. Inhibition of complement activation by the peptides of the classical system was determined using lysis assays with sensitized sheep red blood cells or porcine aortic endothelial cells as targets and of the alternate complement pathway using guinea pig red blood cells as targets. Two transplant models were used to study the effects of administering peptides to recipients: rat heart transplant to presensitized mouse, and guinea heart transplant to PVG C6-deficient rats.

RESULTS

CBP2 and WY-conjugates inhibited immunoglobulin aggregate binding to C1q. The peptides also inhibited human complement-mediated lysis of sensitized sheep red blood cells and porcine aortic endothelial cells in a dose-dependent manner and the WY-conjugates prevented activation of the alternate complement pathway as shown by inhibition of guinea pig red blood cells lysis with human serum. In addition, the use of the peptides and conjugates resulted in significant prolongation of xenograft survival.

CONCLUSIONS

The CBP2 and WY peptides exhibit the functional activity of inhibition of complement activation. These peptides also prolong xenograft survival and thus provide reagents for the study of the importance of C1q and other complement components in transplant rejection mechanisms.