Hole Hopping through Cytochrome P450.

High-potential iron-oxo species are intermediates in the catalytic cycles of oxygenase enzymes. They can cause heme degradation and irreversible oxidation of nearby amino acids. We have proposed that there are protective mechanisms in which hole hopping from oxidized hemes through tryptophan/tyrosine chains generates a surface-exposed amino-acid oxidant that could be rapidly disarmed by reaction with cellular reductants. In investigations of cytochrome P450BM3, we identified Trp96 as a critical residue that could play such a protective role. This Trp is cation-π paired with Arg398 in 81% of mammalian P450s. Here we report on the effect of the Trp/Arg cation-π interaction on Trp96 formal potentials as well as on electronic coupling strengths between Trp96 and the heme both for wild type cytochrome P450 and selected mutants. Mutation of Arg398 to His, which decreases the Trp96 formal potential, increases Trp-heme electronic coupling; however, surprisingly, the rate of phototriggered electron transfer from a Ru-sensitizer (through Trp96) to the P450BM3 heme was unaffected by the Arg398His mutation. We conclude that Trp96 has moved away from Arg398, suggesting that the protective mechanism for P450s with this Trp-Arg pair is conformationally gated.

Mercury emissions from Peruvian gold shops: Potential ramifications for Minamata compliance in artisanal and small-scale gold mining communities.

Ratification of the Minamata Convention on Mercury has led to the establishment of Peruvian regulations limiting mercury concentrations in air to 2000 ng/m3over a 24-hr measurement period. As a result, three communities in Madre de Dios, Peru were mapped during October 2017 to determine Hg0 vapor concentrations in the air. The town of Tres Islas exhibited Hg0 concentrations less than 200 ng/m3: the minimum risk level defined by the Agency for Toxic Substances and Disease Registry. These low concentrations were reflective of a town in the region with limited exposure to artisanal and small-scale gold mining (ASGM). However, the ASGM communities of Laberinto and Delta One exhibited concentrations of Hg0 vapor that exceeded 2,000,000 ng/m3 surrounding active gold shops, where amalgams and processed amalgams were heated with open flames. Laberinto was reevaluated in May 2018 during which time Hg0 levels on the sidewalks in front of gold shops again exceeded 2,000,000 ng/m3. Within the scope of this paper a rapid mapping technique allows for the detection of sources of Hg0 pollution and identifies neighborhoods that require intervention to decrease Hg0 emissions. In addition, this work highlights the difficulties of measuring total gaseous mercury in ASGM communities with gold shops according to the Peruvian law.

Rituximab in Lymphoma and Chronic Lymphocytic Leukaemia: A Practice Guideline.

Rituximab is the first monoclonal antibody to be approved for use by the US Food and Drug Administration in cancer. Its role in the treatment of non-Hodgkin lymphoma, including chronic lymphocytic leukaemia (CLL), has evolved significantly. We aimed to systematically review and update the literature on rituximab in lymphoma and CLL, and provide evidence-based consensus guidelines for its rational use. Validated methodology from the Cancer Care Ontario Program in Evidence-based Care was used. A comprehensive literature search was completed by a methodologist from the Hematology Disease Site Group of Cancer Care Ontario. Data were extracted from randomised controlled trials of rituximab-containing chemotherapy regimens for patients with lymphoma or CLL. Fifty-six primary randomised controlled trials were retrievable and met all inclusion criteria. Clinically important benefits in progression-free survival or overall survival were seen in the following settings: (i) addition of rituximab to combination chemotherapy for initial treatment of aggressive B-cell lymphomas, including diffuse large B-cell lymphoma, Burkitt lymphoma and HIV-related lymphoma with CD4 count ≥50/mm3; (ii) addition of rituximab to combination chemotherapy for initial and subsequent treatment of follicular lymphoma and other indolent B-cell lymphomas; (iii) use of rituximab maintenance in patients with indolent B-cell lymphomas who have responded to chemoimmunotherapy; (iv) addition of rituximab to fludarabine-based chemotherapy or chlorambucil for initial treatment of CLL. The consensus opinion of the Hematology Disease Site Group is that rituximab is recommended for these indications.

Follow-up care for survivors of lymphoma who have received curative-intent treatment.

OBJECTIVE: This evidence summary set out to assess the available evidence about the follow-up of asymptomatic survivors of lymphoma who have received curative-intent treatment. METHODS: The medline and embase databases and the Cochrane Database of Systematic Reviews were searched for evidence published between 2000 and August 2015 relating to lymphoma survivorship follow-up. The evidence summary was developed by a Working Group at the request of the Cancer Care Ontario Survivorship and Cancer Imaging programs because of the absence of evidence-based practice documents in Ontario for the follow-up and surveillance of asymptomatic patients with lymphoma in complete remission. RESULTS: Eleven retrospective studies met the inclusion criteria. The proportion of relapses initially detected by clinical manifestations ranged from 13% to 78%; for relapses initially detected by imaging, the proportion ranged from 8% to 46%. Median time for relapse detection ranged from 8.6 to 19 months for patients initially suspected because of imaging and from 8.6 to 33 months for those initially suspected because of clinical manifestations. Only one study reported significantly earlier relapse detection for patients initially suspected because of clinical manifestations (mean: 4.5 months vs. 6.0 months, p = 0.042). No benefit in terms of overall survival was observed for patients depending on whether their relapse was initially detected because of clinical manifestations or surveillance imaging. SUMMARY: Findings in the present study support the importance of improving awareness on the part of survivors and clinicians about the symptoms that might be associated with recurrence. The evidence does not support routine imaging for improving outcomes in this patient population.

Hepatitis B reactivation in HBsAg-negative/HBcAb-positive patients receiving rituximab for lymphoma: a meta-analysis.

Patients with chronic hepatitis B (HBsAg-positive) are at risk of viral reactivation if rituximab is administered without antiviral treatment, a potentially fatal complication of treatment. Patients with so-called 'resolved hepatitis B virus infection' (HBsAg-negative/cAb-positive) may also be at risk. We performed a systematic review of the English and Chinese language literature to estimate the risk of hepatitis B virus (HBV) reactivation in HBsAg-negative/cAb-positive patients receiving rituximab for lymphoma. A pooled risk estimate was calculated for HBV reactivation. The impact of HBsAb status and study design on reactivation rates was explored. Data from 578 patients in 15 studies were included. 'Clinical HBV reactivation', (ALT >3 × normal and either an increase in HBV DNA from baseline or HBsAg seroreversion), was estimated at 6.3% (I(2) = 63%, P = 0.006). Significant heterogeneity was detected. Reactivation rates were higher in prospective vs retrospective studies (14.2% vs 3.8%; OR = 4.39, 95% CI 0.83-23.28). Exploratory analyses found no effect of HBsAb status on reactivation risk (OR = 0.083; P = 0.151). Our meta-analysis confirms a measurable and potentially substantial risk of HBV reactivation in HBsAg-negative/cAb-positive patients exposed to rituximab. However, heterogeneity in the existing literature limits the generalizability of our findings. Large, prospective studies, with uniform definitions of HBV reactivation, are needed to clarify the risk of HBV reactivation in HBsAg-negative/cAb-positive patients.

Prolonged clinical remissions in patients with relapsed or refractory follicular lymphoma treated with autologous stem cell transplantation incorporating rituximab.

Three sequential phase II trials were conducted with different immunotherapy approaches to enhance the outcome of autologous transplant (high-dose therapy and autologous stem cell transplantation (HDT/ASCT)) for recurrent follicular lymphoma. Seventy-three patients were enrolled from 1996 to 2009. Patients received HDT/ASCT combined with (1) interferon-α 3 MU/m(2) subcutaneously (SC) three times per week (TIW) for 2 years post-ASCT, (2) rituximab (R) 375 mg/m(2) for in vivo purging 3-5 days pre-stem cell collection and 2 × 4 weekly R at 2 and 6 months post-ASCT, respectively, or (3) three infusions of R pre-stem cell collection followed by 6× R weekly and interferon-α 3 MU/m(2) SC TIW. Although not statistically significant, progression-free survival (PFS) for patients who received rituximab was 56.4 and 49.1% at 5 and 10 years compared to 36 and 21% in those who did not receive rituximab. Molecular relapse post-HDT/ASCT was the strongest predictor of PFS in a multivariate analysis. Molecular relapse was coincident with or preceded clinical relapses in 84% of patients who relapsed­median of 12 months (range 0-129 months). Adverse events included secondary malignancy, transformation to diffuse large B cell lymphoma, prolonged mostly asymptomatic hypogammaglobulinemia, and pulmonary fibrosis. The long-term toxicity profile must be considered when selecting patients for this treatment.

Large outbreak of Legionnaires' disease and Pontiac fever at a military base.

We investigated a mixed outbreak of Legionnaires' disease (LD) and Pontiac fever (PF) at a military base to identify the outbreak's environmental source as well as known legionellosis risk factors. Base workers with possible legionellosis were interviewed and, if consenting, underwent testing for legionellosis. A retrospective cohort study collected information on occupants of the buildings closest to the outbreak source. We identified 29 confirmed and probable LD and 38 PF cases. All cases were exposed to airborne pathogens from a cooling tower. Occupants of the building closest to the cooling tower were 6·9 [95% confidence interval (CI) 2·2-22·0] and 5·5 (95% CI 2·1-14·5) times more likely to develop LD and PF, respectively, than occupants of the next closest building. Thorough preventive measures and aggressive responses to outbreaks, including searching for PF cases in mixed legionellosis outbreaks, are essential for legionellosis control.

CAH to CAH: EHR implementation advice to critical access hospitals from peer experts and other key informants.

UNLABELLED: The US government allocated $30 billion to implement electronic health records (EHRs) in hospitals and provider practices through policy addressing Meaningful Use (MU). Most small, rural hospitals, particularly those designated as Critical Access Hospitals (CAHs), comprising nearly a quarter of US hospitals, had not implemented EHRs before. Little is known about implementation in this setting. Socio-technical factors differ between larger hospitals and CAHs, which continue to lag behind other hospitals in EHR adoption. OBJECTIVE: The main objective is to provide EHR implementation advice for CAHs from a spectrum of experts with an emphasis on recommendations from their peers at CAHs that have undertaken the process. The secondary objective is to begin to identify implementation process differences at CAHs v. larger hospitals. METHODS: We interviewed 41 experts, including 16 CAH staff members from EHR teams at 10 CAHs that recently implemented EHRs. We qualitatively analyzed the interviews to ascertain themes and implementation recommendations. RESULTS: Nineteen themes emerged. Under each theme, comments by experts provide in-depth advice on all implementation stages including ongoing optimization and use. We present comments for three top themes as ranked by number of CAH peer experts commenting - EHR System Selection, EHR Team, and Preparatory Work - and for two others, Outside Partners/Resources and Clinical Decision Support (CDS)/Knowledge Management (KM). Comments for remaining themes are included in tables. DISCUSSION: CAH experts rank the themes differently from all experts, a likely indication of the differences between hospitals. Comments for each theme indicate the specific difficulties CAHs encountered. CAH staffs have little or no EHR experience before implementation. A factor across themes is insufficient system and process knowledge, compounded by compressed implementation schedules. Increased, proactive self-education, via available outside partners and information resources, will mitigate difficulties and aid CAHs in meeting increased CDS requirements in MU Stages 2 and 3.

Lenalidomide in multiple myeloma-a practice guideline.

BACKGROUND: Promising new drugs such as lenalidomide, an immunomodulatory agent, are available for the treatment of multiple myeloma. We describe the process of creating a provincial guideline for the use of lenalidomide, alone or in combination with other drugs, in relapsed, refractory, or newly diagnosed disease (including smoldering and symptomatic patients, and candidates and non-candidates for transplant) and in maintenance treatment (after transplant or non-transplant therapy); and for strategies to manage lenalidomide-related toxicities. METHODS: Outcomes of interest included overall survival, event-free survival, progression-free survival, time to progression, time to next treatment, response rate, and incidence of serious toxicity. The medline, embase, and Cochrane Library databases, as well as meeting abstracts and the Web sites of relevant organizations, were systematically searched for relevant literature. RESULTS: Recommendations were developed using the evidence from published studies and the clinical expertise of the working group and of the Cancer Care Ontario Hematology Disease Site Group. CONCLUSIONS: Lenalidomide in combination with dexamethasone can be recommended for both previously untreated and treated patients with multiple myeloma. Guidelines for the management of cytopenias, venous thromboembolism, and second primary malignancies are discussed.

Eight years of Legionnaires' disease transmission in travellers to a condominium complex in Las Vegas, Nevada.

Travel is a risk factor for Legionnaires' disease. In 2008, two cases were reported in condominium guests where we investigated a 2001 outbreak. We reinvestigated to identify additional cases and determine whether ongoing transmission resulted from persistent colonization of potable water. Exposures were assessed by matched case-control analyses (2001) and case-series interviews (2008). We sampled potable water and other water sources. Isolates were compared using sequence-based typing. From 2001 to 2008, 35 cases were identified. Confirmed cases reported after the cluster in 2001-2002 were initially considered sporadic, but retrospective case-finding identified five additional cases. Cases were more likely than controls to stay in tower 2 of the condominium [matched odds ratio (mOR) 6·1, 95% confidence interval (CI) 1·6-22·9]; transmission was associated with showering duration (mOR 23·0, 95% CI 1·4-384). We characterized a clinical isolate as sequence type 35 (ST35) and detected ST35 in samples of tower 2's potable water in 2001, 2002, and 2008. This prolonged outbreak illustrates the importance of striving for permanent Legionella eradication from potable water.

Direct healthcare costs of selected diseases primarily or partially transmitted by water.

Despite US sanitation advancements, millions of waterborne disease cases occur annually, although the precise burden of disease is not well quantified. Estimating the direct healthcare cost of specific infections would be useful in prioritizing waterborne disease prevention activities. Hospitalization and outpatient visit costs per case and total US hospitalization costs for ten waterborne diseases were calculated using large healthcare claims and hospital discharge databases. The five primarily waterborne diseases in this analysis (giardiasis, cryptosporidiosis, Legionnaires' disease, otitis externa, and non-tuberculous mycobacterial infection) were responsible for over 40 000 hospitalizations at a cost of $970 million per year, including at least $430 million in hospitalization costs for Medicaid and Medicare patients. An additional 50 000 hospitalizations for campylobacteriosis, salmonellosis, shigellosis, haemolytic uraemic syndrome, and toxoplasmosis cost $860 million annually ($390 million in payments for Medicaid and Medicare patients), a portion of which can be assumed to be due to waterborne transmission.

The California Pertussis Epidemic 2010: A Review of 986 Pediatric Case Reports From San Diego County.

BACKGROUND: The California Department of Public Health (CDPH) declared a pertussis epidemic on 23 June 2010. More cases were reported in 2010 (9146) than in any year since 1947. We describe the characteristics of pertussis epidemiology and disease from 986 reported cases in children in San Diego County (population 3.2 million). METHODS: Descriptive statistics were abstracted from CDPH pertussis case report forms that were completed by public health nurses investigating reports of positive laboratory results for pertussis and reports of illnesses compatible with pertussis. RESULTS: Of 1144 reported adult and pediatric cases, 753 (66%) were confirmed and 391 were probable/suspect. Children aged <19 years comprised 86% of all reported cases in San Diego County; of these, 22% were aged 11-18 years, 29% were aged 6-10 years, 27% were aged 1-5 years, and 22% were aged <1 year (with 70% aged <6 months). Case rates were highest in infants aged <6 months (651 per 100 000 population). Of those aged >1 year, the highest attack rates were in preschool children aged 1-5 years (114 per 100 000) and elementary school children aged 6-10 years (141 per 100 000). Of 51 children hospitalized, 82% were aged <6 months; 2 deaths occurred in these young infants. Paroxysmal cough was noted in over 70% of children in all age groups; post-tussive vomiting occurred in 36% (aged 11-18 years) to 57% (aged <6 months) of children. CONCLUSIONS: Pertussis vaccine efficacy may decrease more rapidly than previously believed, facilitating spread of pertussis in elementary school-aged children. The highest case rates and the only mortality occurred in infants aged <6 months.

HIV-Associated Burkitt Lymphoma: Good Efficacy and Tolerance of Intensive Chemotherapy Including CODOX-M/IVAC with or without Rituximab in the HAART Era.

Background. The outcome of HIV-associated non-Hodgkin lymphoma (NHL) has improved substantially in the highly active antiretroviral therapy (HAART) era. However, HIV-Burkitt lymphoma (BL), which accounts for up to 20% of HIV-NHL, has poor outcome with standard chemotherapy. Patients and Methods. We retrospectively reviewed HIV-BL treated in the HAART era with the Magrath regimen (CODOX-M/IVAC±R) at four Canadian centres. Results. Fourteen patients with HIV-BL received at least one CODOX-M/IVAC±R treatment. Median age at BL diagnosis was 45.5 years, CD4 count 375 cells/mL and HIV viral load (VL) <50 copies/mL. Patients received PCP prophylaxis and G-CSF, 13 received HAART with chemotherapy and 10 rituximab. There were 63 episodes of toxicity, none fatal, including: bacterial infection, n = 20; grade 3-4 hematologic toxicity, n = 14; febrile neutropenia, n = 7; oral thrush; and ifosfamide neurological toxicity, n = 1 each. At a median followup of 11.7 months, 12 (86%) patients are alive and in remission. All 10 patients who received HAART, chemotherapy, and rituximab are alive. CD4 counts and HIV VL 6 months following BL therapy completion (n = 5 patients) were >250 cells/mL and undetectable, respectively, in 4. Conclusion. Intensive chemotherapy with CODOX-M/IVAC±R yielded acceptable toxicity and good survival rates in patients with HIV-associated Burkitt lymphoma receiving HAART.

Screening for hepatitis B surface antigen before chemotherapy: current practice and opportunities for improvement.

INTRODUCTION: Hepatitis B virus (hbv) reactivation is a recognized complication of chemotherapy. The U.S. Centers for Disease Control and Prevention recommend that all patients be screened for the hbv surface antigen (hbsag) before chemotherapy. We sought to determine the frequency of hbsag testing before chemotherapy at our hospital and to increase the frequency of testing to more than 90% of patients starting chemotherapy. METHODS: Using a retrospective electronic chart review, we identified the frequency of hbsag testing for patients initiated on intravenous chemotherapy at out institution between March 2006 and March 2007. The frequency of left ventricular function testing in the subgroup of patients receiving potentially cardiotoxic chemotherapy was identified as a comparator. An educational intervention was developed and delivered to the multidisciplinary oncology team. The frequency of hbsag testing was determined post intervention. Qualitative interviews were conducted with the members of the oncology team to identify risk perception and barriers to testing. RESULTS: Of 208 patients started on intravenous chemotherapy between March 2006 and March 2007, only 28 (14%) were tested for hbsag. All 138 patients scheduled for cardiotoxic chemotherapy (100%) underwent left ventricular function testing. In the post-intervention phase, of 74 patients started on intravenous chemotherapy, 24 (31%) underwent hbsag testing, with 1 patient testing positive. CONCLUSIONS: The frequency of testing for hbsag before chemotherapy was very low at our institution. An educational intervention resulted in only a modest improvement. Potential barriers to routine screening include lack of awareness about existing guidelines, controversy about the evidence that supports hbsag testing guidelines, and a perception by physicians that hbv reactivation does not occur with solid tumours.

Biochemical and molecular analysis of carboxylesterase-mediated hydrolysis of cocaine and heroin.

BACKGROUND AND PURPOSE: Carboxylesterases (CEs) metabolize a wide range of xenobiotic substrates including heroin, cocaine, meperidine and the anticancer agent CPT-11. In this study, we have purified to homogeneity human liver and intestinal CEs and compared their ability with hydrolyse heroin, cocaine and CPT-11. EXPERIMENTAL APPROACH: The hydrolysis of heroin and cocaine by recombinant human CEs was evaluated and the kinetic parameters determined. In addition, microsomal samples prepared from these tissues were subjected to chromatographic separation, and substrate hydrolysis and amounts of different CEs were determined. KEY RESULTS: In contrast to previous reports, cocaine was not hydrolysed by the human liver CE, hCE1 (CES1), either as highly active recombinant protein or as CEs isolated from human liver or intestinal extracts. These results correlated well with computer-assisted molecular modelling studies that suggested that hydrolysis of cocaine by hCE1 (CES1), would be unlikely to occur. However, cocaine, heroin and CPT-11 were all substrates for the intestinal CE, hiCE (CES2), as determined using both the recombinant protein and the tissue fractions. Again, these data were in agreement with the modelling results. CONCLUSIONS AND IMPLICATIONS: These results indicate that the human liver CE is unlikely to play a role in the metabolism of cocaine and that hydrolysis of this substrate by this class of enzymes is via the human intestinal protein hiCE (CES2). In addition, because no enzyme inhibition is observed at high cocaine concentrations, potentially this route of hydrolysis is important in individuals who overdose on this agent.

Is age-dependent, ketamine-induced apoptosis in the rat somatosensory cortex influenced by temperature?

General anesthetics have long been thought to be relatively safe but recent clinical studies have revealed that exposure of very young children (4 years or less) to agents that act by blocking the N-methyl-D-aspartate receptor (NMDAR) can lead to cognitive deficits as they mature. In rodent and non-human primate studies, blockade of this receptor during the perinatal period leads to a number of molecular, cellular and behavioral pathologies. Despite the overwhelming evidence from such studies, doubt remains as to their clinical relevance. A key issue is whether the primary injury (apoptotic cell death) is specific to receptor blockade or due to non-specific, patho-physiological changes. Principal to this argument is that loss of core body temperature following NMDAR blockade could explain why injury is observed hours later. We therefore examined the neurotoxicity of the general anesthetic ketamine in P7, P14 and P21 rats while monitoring core body temperature. We found that, at P7, ketamine induced the pro-apoptotic enzyme activated caspase-3 in a dose-dependent manner. As expected, injury was greatly diminished by P14 and absent by P21. However, contrary to expectations, we found that core body temperature was not a factor in determining injury. Our data imply that injury is directly related to receptor blockade and is unlikely to be overcome by artificially changing core body temperature.

Rituximab purging and maintenance combined with auto-SCT: long-term molecular remissions and prolonged hypogammaglobulinemia in relapsed follicular lymphoma.

We enrolled 23 patients with relapsed follicular lymphoma (FL) in a prospective single-arm study of auto-SCT combined with in vivo rituximab graft purging and post transplant rituximab maintenance. Minimal residual disease was monitored with quantitative PCR testing. With a median follow-up of 74.2 months, neither median overall survival (OS) nor PFS has been reached. Here, 5-year OS and 5-year PFS are 78% (95% confidence interval (CI) 61-95%) and 59% (95% CI 38-80%), respectively. Time to progression (TTP) with the experimental regimen was significantly improved compared with TTP with the last prior treatment (P<0.001). Durable molecular remissions occurred in 11 of 13 assessable patients. PFS was significantly longer in patients who achieved a molecular remission by 3 months post-auto-SCT (P=0.001). Prolonged hypogammaglobulinemia occurred in most patients; however, no increase in major infections was observed.

The preservation of quartz grain surface textures following vehicle fire and their use in forensic enquiry.

During a terrorist trial, dispute arose as to whether the temperature produced in a car fire was sufficient to destroy quartz grain surface textures. A series of seven sequential experiments showed that the temperature for quartz surface texture modification/destruction and the production of vugs, vesicles and glassy precipitation ('snowdrifting') occurred at 1200 degrees C under normal atmospheric conditions. By adding a number of man-made and natural substances, it was found that only the presence of salts depressed this modification temperature (to 900 degrees C). Experiments to determine the temperature of fire in a car indicated that the maximum temperature produced under natural conditions (810 degrees C) was insufficient to affect the quartz grain surface textures. These results confirm the use of surface texture analysis of quartz grains recovered from the remains of cars subjected to fire and their use as a forensic indicator.

Increased rainfall is associated with increased risk for legionellosis.

Legionnaires' disease (LD) is caused by Legionella species, most of which live in water. The Mid-Atlantic region experienced a sharp rise in LD in 2003 coinciding with a period of record-breaking rainfall. To investigate a possible relationship, we analysed the association between monthly legionellosis incidence and monthly rainfall totals from January 1990 to December 2003 in five Mid-Atlantic states. Using negative binomial model a 1-cm increase in rainfall was associated with a 2.6% (RR 1.026, 95% CI 1.012-1.040) increase in legionellosis incidence. The average monthly rainfall from May to September 1990-2002 was 10.4 cm compared to 15.7 cm from May to September 2003. This change in rainfall corresponds to an increased risk for legionellosis of approximately 14.6% (RR 1.146, 95% CI 1.067-1.231). Legionellosis incidence increased during periods of increased rainfall; identification of mechanisms that increase exposure and transmission of Legionella during rainfall might lead to opportunities for prevention.