Hepatic Huwe1 loss protects mice from non-alcoholic fatty liver disease through lipid metabolic rewiring

Non-alcoholic fatty liver disease (NAFLD) is the most pervasive liver pathology worldwide. Here, we demonstrate that the ubiquitin E3 ligase Huwe1 is vital in NAFLD pathogenesis. Using mass spectrometry and RNA sequencing, we reveal that liver-specific deletion of Huwe1 (Huwe1LKO) in 1-year-old mice (approximately middle age in humans) elicits extensive lipid metabolic reprogramming that involves downregulation of de novo lipogenesis and fatty acid uptake, upregulation of fatty acid β-oxidation, and increased oxidative phosphorylation. ChEA transcription factor prediction analysis inferred these changes result from attenuated PPARɑ, LXR, and RXR activity in Huwe1LKO livers. Consequently, Huwe1LKO mice fed chow diet exhibited significantly reduced hepatic steatosis and superior glucose tolerance compared to wild-type mice. Huwe1LKO also conferred protection from high-fat diet-induced hepatic steatosis by 6-months of age, with increasingly robust differences observed as mice reached middle age. Together, we present evidence that Huwe1 plays a critical role in the development of age- and diet-induced NAFLD.

X-Linked Huwe1 Is Essential for Oocyte Maturation and Preimplantation Embryo Development

HUWE1 is a HECT-domain ubiquitin E3 ligase expressed in various tissues. Although HUWE1 is known to promote degradation of the tumor suppressor p53, given a growing list of its substrates, in vivo functions of HUWE1 remain elusive. Here, we investigated the role of HUWE1 in the female reproductive system. Homozygous deletion of Huwe1 in mouse oocytes of primary follicles caused oocyte death and female infertility, whereas acute depletion of HUWE1 protein by Trim-Away technology did not impact oocytes from antral follicles. Interestingly, oocytes from Huwe1 heterozygous females matured and fertilized normally, but the majority of embryos that lacked maternal Huwe1 were arrested at the morula stage after fertilization. Consequently, Huwe1 heterozygous females only produced wild-type pups. Concomitant knockout of p53 did not recover fertility of the Huwe1 knockout females. These findings make HUWE1 a unique and critical maternal factor indispensable for maintaining the quality of oocytes and embryos.

CD36-Mediated Metabolic Rewiring of Breast Cancer Cells Promotes Resistance to HER2-Targeted Therapies

Although it is established that fatty acid (FA) synthesis supports anabolic growth in cancer, the role of exogenous FA uptake remains elusive. Here we show that, during acquisition of resistance to HER2 inhibition, metabolic rewiring of breast cancer cells favors reliance on exogenous FA uptake over de novo FA synthesis. Through cDNA microarray analysis, we identify the FA transporter CD36 as a critical gene upregulated in cells with acquired resistance to the HER2 inhibitor lapatinib. Accordingly, resistant cells exhibit increased exogenous FA uptake and metabolic plasticity. Genetic or pharmacological inhibition of CD36 suppresses the growth of lapatinib-resistant but not lapatinib-sensitive cells in vitro and in vivo. Deletion of Cd36 in mammary tissues of MMTV-neu mice significantly attenuates tumorigenesis. In breast cancer patients, CD36 expression increases following anti-HER2 therapy, which correlates with a poor prognosis. Our results define CD36-mediated metabolic rewiring as an essential survival mechanism in HER2-positive breast cancer.

Engineering liposomal nanoparticles of cholesterol-tethered amphiphilic Pt(iv) prodrugs with prolonged circulation time in blood

Cisplatin is a platinum-based chemotherapeutic agent widely used in the treatment of various solid tumors. However, a major challenge in the use of cisplatin and in the development of cisplatin derivatives, namely Pt(iv) prodrugs, is their premature reduction in the bloodstream before reaching cancer cells. To circumvent this problem, we designed liposomal nanoparticles coupled with a cholesterol-tethered amphiphilic Pt(iv) prodrug. The addition of cholesterol served to stabilize the formation of the liposome, while selectively incorporating cholesterol as the axial ligand also allowed the Pt(iv) prodrug to readily migrate into the liposomal bilayer. Notably, upon embedding into the nanoparticles, the Pt(iv) prodrug showed marked resistance against premature reduction in human plasma in vitro. Pharmacokinetic analysis in a mouse model also showed that the nanoparticles significantly extend the half-life of the Pt(iv) prodrug to 180 min, which represents a >6-fold increase compared to cisplatin. Importantly, such lipid modification did not compromise the genotoxicity of cisplatin, as the Pt(iv) prodrug induced DNA damage and apoptosis in ovarian cancer cell lines efficiently. Taken together, our strategy provides a novel insight as to how to stabilize a platinum-based compound to increase the circulation time in vivo, which is expected to enhance the efficacy of drug treatment.

Direct regulation of Chk1 protein stability by E3 ubiquitin ligase HUWE1

The HECT E3 ubiquitin ligase HUWE1 is required for a wide array of important functions in cell biology. Although HUWE1 is known to play a role in DNA damage signaling, the mechanism(s) that underlie this function remain elusive. HUWE1 regulates effectors of DNA replication and genotoxic stress tolerance. However, the loss of HUWE1 can also result in the accrual of significant endogenous DNA damage due to insufficient remediation of replication stress induced by an overabundance of key substrates. We discovered that HUWE1 depletion leads to a significant increase in levels of the single-strand break effector kinase Chk1, independent of the DNA damage response, activation of apical DNA damage repair (DDR) signaling kinases (ATM and ATR), and the tumor suppressor p53. We also identified multiple lysine residues on Chk1 that are polyubiquitinated by HUWE1 in vitro, many of which are within the kinase domain. HUWE1 knockdown also markedly prolonged the protein half-life of Chk1 in steady-state conditions and resulted in greater stabilization of Chk1 protein than depletion of Cul4A, an E3 ubiquitin ligase previously described to control Chk1 abundance. Moreover, prolonged replication stress induced by hydroxyurea or camptothecin resulted in a reduction of Chk1 protein levels, which was rescued by HUWE1 knockdown. Our study indicates that HUWE1 plays a significant role in the regulation of the DDR signaling pathway by directly modulating the abundance of Chk1 protein.

CD36: a key mediator of resistance to HER2 inhibitors in breast cancer

Acquired resistance to anti-HER2 therapy is a significant clinical challenge in breast cancer. We recently discovered that during acquisition of resistance to HER2 inhibition, upregulation of the fatty acid transporter CD36 takes place, playing a key role in metabolic rewiring and resistance to anti-HER2 therapy.

Regulation of the p53 Family Proteins by the Ubiquitin Proteasomal Pathway

The tumor suppressor p53 and its homologues, p63 and p73, play a pivotal role in the regulation of the DNA damage response, cellular homeostasis, development, aging, and metabolism. A number of mouse studies have shown that a genetic defect in the p53 family could lead to spontaneous tumor development, embryonic lethality, or severe tissue abnormality, indicating that the activity of the p53 family must be tightly regulated to maintain normal cellular functions. While the p53 family members are regulated at the level of gene expression as well as post-translational modification, they are also controlled at the level of protein stability through the ubiquitin proteasomal pathway. Over the last 20 years, many ubiquitin E3 ligases have been discovered that directly promote protein degradation of p53, p63, and p73 in vitro and in vivo. Here, we provide an overview of such E3 ligases and discuss their roles and functions.

Clinical outcomes and the role of adjuvant therapy sequencing in Type II uterine cancer following definitive surgical treatment

PURPOSE OF INVESTIGATION

Because of rarity, consensus on adjuvant therapies for Type II endometrial cancers (BC) remains undefined. Reporting their institutional outcomes, the present authors assessed the impact of adjuvant therapies on recurrence and overall survival in women with 2009 FIGO Stage I-III Type II BC.

MATERIAL AND METHODS

The authors identified 108 women, treated with definitive surgery between 2000-2013, with pathologically-confirmed Type II EC (non-endometrioid [NEM, n=801 and high grade endometrioid [G3EEC, n=28]) Cox proportional hazard models were used to assess the effect of prognostic variables on disease-free (DFS) and overall survival (OS). Kaplan-Meier method was used to assess survival.

RESULTS

Of the 108 women, 83 (77%) were African American (AA). Fifty-nine (55%), 12 (11%), and 37 (34%) were Stage I, II, and III, respectively. Ninety-seven patients received adjuvant therapy: 52 (radiation only), four (chemotherapy only), and 40 (combined). During follow-up (median 41 months), 44 patients (41%) recurred. Five-year DFS was 53% overall (48% [NEM], 80% [G3EEC]). Five-year OS was 75% overall (68% [NEM], 95% [G3EEC]). On multivariate analysis, lower stage and adjuvant radiation improved DFS. Higher stage, NEM, and increasing age were poor prognostic indicators of OS.

CONCLUSION

Representing a large single institutional cohort for Type II BC, the present study's observed sur- vival rates are consistent with previous studies, despite the relatively high frequency of carcinosarcoma and Stage III/nodal disease. The protective effect on recurrence was not lost when radiation was delayed for chemotherapy. The present results support a multimodal adjuvant approach for treating all stages of invasive NEM EC.

Nociceptive and pro-inflammatory effects of dimethylallyl pyrophosphate via TRPV4 activation

BACKGROUND AND PURPOSE

Sensory neuronal and epidermal transient receptor potential ion channels (TRPs) serve an important role as pain sensor molecules. While many natural and synthetic ligands for sensory TRPs have been identified, little is known about the endogenous activator for TRPV4. Recently, we reported that endogenous metabolites produced by the mevalonate pathway regulate the activities of sensory neuronal TRPs. Here, we show that dimethylallyl pyrophosphate (DMAPP), a substance produced by the same pathway is an activator of TRPV4.

EXPERIMENTAL APPROACH

We examined the effects of DMAPP on sensory TRPs using Ca²⁺ imaging and whole-cell electrophysiology experiments with a heterologous expression system (HEK293T cells transfected with individual TRP channels), cultured sensory neurons and keratinocytes. We then evaluated nociceptive behavioural and inflammatory changes upon DMAPP administration in mice in vivo.

KEY RESULTS

In the HEK cell heterologous expression system, cultured sensory neurons and keratinocytes, µM concentrations of DMAPP activated TRPV4. Agonistic and antagonistic potencies of DMAPP for other sensory TRP channels were examined and activation of TRPV3 by camphor was found to be inhibited by DMAPP. In vivo assays, intraplantar injection of DMAPP acutely elicited nociceptive flinches that were prevented by pretreatment with TRPV4 blockers, indicating that DMAPP is a novel pain-producing molecule through TRPV4 activation. Further, DMAPP induced acute inflammation and noxious mechanical hypersensitivities in a TRPV4-dependent manner.

CONCLUSIONS AND IMPLICATIONS

Overall, we found a novel sensory TRP acting metabolite and suggest that its use may help to elucidate the physiological role of TRPV4 in nociception and associated inflammation.

17(R)-resolvin D1 specifically inhibits transient receptor potential ion channel vanilloid 3 leading to peripheral antinociception

BACKGROUND AND PURPOSE

Transient receptor potential ion channel vanilloid 3 (TRPV3) is expressed in skin keratinocytes and plays an important role in thermal and chemical nociceptions in the periphery. The presence of TRPV3 inhibitors would improve our understanding of TRPV3 function and help to develop receptor-specific analgesics. However, little is known about physiological substances that specifically inhibit TRPV3 activity. Here, we investigated whether 17(R)-resolvin D1 (17R-RvD1), a naturally occurring pro-resolving lipid specifically affects TRPV3 activity.

EXPERIMENTAL APPROACH

We examined the effect of 17R-RvD1 on sensory TRP channels using Ca(2+) imaging and whole cell electrophysiology experiments in a HEK cell heterologous expression system, cultured sensory neurons and keratinocytes. We also examined changes in sensory TRP agonist-specific acute licking/flicking or flinching behaviours and mechanical and thermal pain behaviours using Hargreaves, Randall-Selitto and von Frey assay systems in the absence and presence of inflammation.

KEY RESULTS

We showed that 17R-RvD1 specifically suppresses TRPV3-mediated activity at nanomolar and micromolar concentrations. The voltage-dependence of TRPV3 activation by camphor was shifted rightwards by 17R-RvD1, which indicates its inhibitory mechanism is as a result of a shift in voltage-dependence. Consistently, TRPV3-specific acute pain behaviours were attenuated by locally injected 17R-RvD1. Moreover, the administration of 17R-RvD1 significantly reversed the thermal hypersensitivity that occurs during an inflammatory response. Knockdown of epidermal TRPV3 blunted these antinociceptive effects of 17R-RvD1.

CONCLUSIONS AND IMPLICATIONS

17R-RvD1 is a novel natural inhibitory substance specific for TRPV3. The results of our behavioural studies suggest that 17R-RvD1 has acute analgesic potential via TRPV3-specific mechanisms.

Resolvin D1 attenuates activation of sensory transient receptor potential channels leading to multiple anti-nociception

BACKGROUND AND PURPOSE

Temperature-sensitive transient receptor potential ion channels (thermoTRPs) expressed in primary sensory neurons and skin keratinocytes play a crucial role as peripheral pain detectors. Many natural and synthetic ligands have been found to act on thermoTRPs, but little is known about endogenous compounds that inhibit these TRPs. Here, we asked whether resolvin D1 (RvD1), a naturally occurring anti-inflammatory and pro-resolving lipid molecule is able to affect the TRP channel activation.

EXPERIMENTAL APPROACH

We examined the effect of RvD1 on the six thermoTRPs using Ca(2+) imaging and whole cell electrophysiology experiments using the HEK cell heterologous expression system, cultured sensory neurons and HaCaT keratinocytes. We also checked changes in agonist-specific acute licking/flicking or flinching behaviours and TRP-related mechanical and thermal pain behaviours using Hargreaves, Randall-Selitto and von Frey assay systems with or without inflammation.

KEY RESULTS

RvD1 inhibited the activities of TRPA1, TRPV3 and TRPV4 at nanomolar and micromolar levels. Consistent attenuations in agonist-specific acute pain behaviours by immediate peripheral administration with RvD1 were also observed. Furthermore, local pretreatment with RvD1 significantly reversed mechanical and thermal hypersensitivity in inflamed tissues.

CONCLUSIONS AND IMPLICATIONS

RvD1 was a novel endogenous inhibitor for several sensory TRPs. The results of our behavioural studies suggest that RvD1 has an analgesic potential via these TRP-related mechanisms.

Pre and post-interventional pattern of self medication in three common illnesses in staff of a tertiary hospital

Objective:

To find the pattern of self medication in three common illnesses (diarrhea, sore throat, common cold) in nonmedical staff of a tertiary care teaching hospital and to study the effect of IEC.

Materials and Methods:

This was a cross sectional study carried out in 100 randomly selected nonmedical staff members. Participants were interviewed by a semi structured questionnaire to obtain information about practice of self medication in the three illnesses. In the second phase participants were educated about proper self medication using Information, Education, and Communication (IEC) intervention. In post test the same information was obtained from the participants using the same questionnaire. Pre and post intervention data was compared to see whether intervention has resulted in any change in the pattern of self medication.

Results:

For all the three diseases the use of medicines including anti microbials did not decrease significantly after intervention. During post test significantly more number of participants were aware about warning symptoms of the disease and precautions to be taken in children and pregnant women. Even during pre intervention many participants were aware about non-pharmacological measures to be adopted in the treatment of these diseases which increased after intervention, though not significantly.

Conclusion:

It is possible to improve self medication practices for the treatment of common illnesses if appropriate IEC intervention is adopted. This requires that all related stakeholders should intensify efforts to educate the general public and ensure appropriate use of OTC medicines.

Laser modulation of heat and capsaicin receptor TRPV1 leads to thermal antinociception

Er,Cr:YSGG lasers are used clinically in dentistry. The advantages of laser therapy include minimal thermal damage and the alleviation of pain. This study examined whether the Er,Cr:YSGG laser has in vivo and in vitro antinociceptive effects in itself. In capsaicin-evoked acute licking/shaking tests and Hargreaves tests, laser irradiation with an aerated water spray suppressed nociceptive behavior in mice. Laser irradiation attenuated TRPV1 activation by capsaicin in Ca(2+) imaging experiments with TRPV1-overexpressing cells and cultured trigeminal neurons. Therefore, the laser-induced behavioral changes are probably due to the loss of TRPV1 activity. TRPV4 activity was also attenuated, but limited mechanical antinociception by the laser was observed. The laser failed to alter the other receptor functions, which indicates that the antinociceptive effect of the laser is dependent on TRPV1. These results suggest that the Er,Cr:YSGG laser has analgesic effects via TRPV1 inhibition. Such mechanistic approaches may help define the laser-sensitive pain modality and increase its beneficial uses.

Lack of association between ACE and bradykinin B2 receptor gene polymorphisms and ACE inhibitor-induced coughing in hypertensive Koreans

BACKGROUND & OBJECTIVE

Angiotensin converting enzyme (ACE) inhibitors are used widely in therapy for hypertension, congestive heart failure and myocardial infarction. However, coughing, one of their major adverse effects limits their use. It is documented that Asians are more liable to coughing than Europeans. The aim of this study was to investigate genetic polymorphism involved in ACE inhibitor-induced coughing.

METHODS

We monitored hypertensive subjects (n = 110) treated with ACE inhibitors, and tested for any associations between ACE inhibitor-induced coughing and polymorphisms in the genes for ACE and the bradykinin B2 receptor, which are suspected to be related to coughing.

RESULTS & DISCUSSION

We found no significant differences between the groups with coughing and without coughing in the frequency of ACE I/D (Insertion/Deletion) polymorphisms. One single nucleotide polymorphism was discovered in the promoter (-58T/C) and, one in intron-exon junction upsteam of exon 2 (-59C/A), of the bradykinin B2 receptor gene. However, no significant correlation was found between those genotypes or allele distributions and ACE inhibitor-induced coughing.

CONCLUSION

We found no significant links between polymorphisms of the ACE gene or bradykinin B2 receptor gene with ACE inhibitor-induced coughing in hypertensive Koreans. But, the topic remains controversial and requires more study.

Septicaemia in scald and flame burns: appraisal of significant differences

One hundred and sixty burn patients suffering from septicaemia, hospitalized in the Al-Babtain Centre burns unit, Kuwait, between June 1992 and May 2001, were studied. Thirty-two patients (20%) had scalds and 128 (80%) flame burns, thus representing a ratio of 1:4 among septicaemic patients. There were 20 males (62.5%) in the scald group, compared to 73 (57%) with flame burns. Flame burns were significantly higher (p &lt; 0.01) among non-Kuwaiti patients. The mean ages of the scald and flame burn patients were respectively 6.2 and 31.5 yr. The mean total body surface area burn in scalds was 20% and in flame burns 49%, which was significantly higher (p < 0.001). The 34 septicaemic episodes in 32 scald patients and 212 such episodes in 128 flame burn patients showed a significantly higher incidence in the latter group. The majority of septicaemic episodes, in scalds (82.4%) and flame burns (57.6%), were due to gram-positive organisms, mainly methicillin-resistant Staphylococcus aureus and methicillin-resistant Staphylococcus epidermidis. A significantly increased number of episodes were due to S. aureus (p < 0.001) and Enterococcus (p < 0.05) in scald patients. More surgical operations were performed in flame burn patients and survival increased significantly with an increasing number of grafting sessions (p < 0.001). The mean hospital stay in flame burn patients (56 days) was significantly higher than in scald patients (23 days) (p < 0.001). It is significant to record that all the 38 deaths (29.7%) were in flame burn septicaemic patients (p < 0.001). The scald and flame burn patients were quite distinct in their demographic and clinical characteristics. The flame burn patients were more vulnerable to septicaemia, with a high risk of mortality.

Two different schedules of docetaxel plus cisplatin as first-line therapy in advanced non-small cell lung cancer: A preliminary result from a randomized phase II study

7135

Background: There has been increasing interest in the use of a weekly administration of docetaxel as a way of reducing its hematologic toxicity. The purpose of this randomized study is to evaluate the toxicity and efficacy of docetaxel and cisplatin combination on two schedules in patients with previously untreated, advanced non-small cell lung cancer (NSCLC). Methods: Consenting patients with stage IIIB/IV or recurrent NSCLC were randomized to receive first-line chemotherapy with cisplatin 75 mg/m2 on day 1, plus either weekly (35 mg/m2 on day 1, 8, 15 of a 4-week cycle) or 3-weekly (75 mg/m2 on day 1 of a 3-week cycle) docetaxel, both for up to 6 cycles. Objectives of this randomized phase II trial were response, toxicity and quality of life (QOL; measured with EORTC QLQ-C30). With a two-stage phase II design, the required number of patients was 39 per each arm. Results: Of 85 patients accrued, 71 patients were evaluable for response and 83 for safety. Baseline characteristics were well-balanced between the two arms: male (56 patients); median age (64 years); adenocarcinoma/squamous cell carcinoma (53/32); stage IIIB/IV/recurrent (12/63/10); ECOG performance status 0/1/2 (20/44/21). Median number of chemotherapy cycles was 3 (1–6) for both arms. Median dose intensities were docetaxel 88%, cisplatin 98% in weekly arm, and docetaxel 97%, cisplatin 98% in 3-weekly arm. The objective responses of weekly and 3-weekly arm were 38% (95% CI, 23–53) and 42% (95% CI, 27–57), respectively. There was significantly more grade 3/4 neutropenia (66% v 12%; P < .001) and febrile neutropenia (40% v 7%; P < .001) on 3-weekly arm but less grade 3/4 diarrhea (2% v 14%; P = .05) and severe skin/nail toxicity (5% v 29%; P = .003). No difference in the rates of treatment delay or dose reduction for both arms; however, 19% of day 15 docetaxel were omitted in weekly arm due to toxicity. Conclusions: Both weekly and 3-weekly docetaxel plus cisplatin appear to be active as first-line chemotherapy for advanced NSCLC, with different safety profiles. Updated results and QOL data, including a prolonged follow-up, will be presented.

No significant financial relationships to disclose.

Second-line chemotherapy with mitomycin C and S-1 in patients with advanced gastric cancer

14083

Background: S-1, a fourth generation oral fluoropyrimidine that mimics infusional 5-fluorouracil, has demonstrated activity against advanced gastric cancer. Based on a single agent activity and in vitro synergy between mitomycin C (MMC) and 5-fluorouracil, we conducted a phase II study to assess the efficacy and tolerability of the combination of S-1 and MMC as second-line chemotherapy for previously treated, advanced gastric cancer. Methods: Patients with measurable gastric cancer, progressive after at least one prior chemotherapy for metastatic disease, were treated with MMC 7 mg/m2 on day 1 and S-1 40 mg/m2 twice daily as an intermittent regimen of 4 weeks of treatment followed by a 2-week rest. Treatment was repeated every 6 weeks, for up to 4 cycles. Objective response rate was the primary endpoint and was evaluated every 2 cycles of chemotherapy. With a single-stage phase II design, at least 25 patients were required. Results: Of the 26 patients registered, 24 patients were evaluable for response and 26 for safety. Eighteen patients (69%) were previously treated with 5-fluorouracil-based chemotherapy, and 10 (39%) were treated with taxanes. The patients’ median age was 55 years (range, 38–73) and 7 (27%) had an ECOG performance status of 2. A total of 64 chemotherapy cycles were delivered (median, 2; range, 1–4). In an intent-to-treat analysis, 6 patients (23%) achieved a partial response, which maintained for 3.5 months. The median progression-free and overall survivals were 4.4 months (95% CI, 1.7–7.2) and 5.4 months (95% CI, 3.4–7.4), respectively. Major toxic effects included stomatitis, diarrhea and fatigue, but were generally mild and manageable. No patient developed hemolytic reaction. Conclusions: Second-line chemotherapy with MMC and S-1 is an effective regimen for advanced gastric cancer with an acceptable toxicity profile and a convenient administration schedule.

No significant financial relationships to disclose.

Prolonged restaurant-associated outbreak of multidrug-resistant Salmonella Typhimurium among patients from several European countries

This report concerns a prolonged restaurant-associated outbreak of infection caused by a multidrug-resistant (ASSuT) strain of Salmonella Typhimurium, phage-type U302, which took place during July and August 2003 and affected people from Denmark and neighbouring countries who had attended a specific restaurant. The outbreak comprised 67 laboratory-verified cases and ten probable cases; however, the actual number of patients was estimated to be more than 390. The outbreak strain was isolated from a buffet which was probably contaminated by an assistant chef who was found to excrete the epidemic strain. An attack rate of 7.3% was estimated and long incubation periods were observed, including one extreme instance of 27 days. This outbreak underscores the importance of conscientious personal hygiene, including frequent washing of hands, for professionals handling food.

Treatment of arsenic in Bangladesh well water using a household co-precipitation and filtration system

Laboratory and field tests were conducted to evaluate the effectiveness of a household filtration process and investigate the effects of phosphate and silicate on the removal of arsenic from Bangladesh groundwater by ferric hydroxides. Fe/As ratios of greater than 40 (mg/mg) were required to reduce arsenic to less than 50 microg/L in Bangladesh well water due to the presence of elevated phosphate and silicate concentrations. The household filtration process included co-precipitation of arsenic by adding a packet (approximately 2 g) of ferric and hypochlorite salts to 20 L of well water and subsequent filtration of the water through a bucket sand filter. A field demonstration study was performed to test the treatment system in seven households in Bangladesh in March and April 2000. Experimental results obtained from the participating families proved that the household treatment process removed arsenic from approximately 300 microg/L in the well water to less than 50 microg/L. The participating families liked this simple and affordable process and used it to prepare clean water for drinking and cooking. A larger scale field test is currently underway.

Fas- and tumor necrosis factor-mediated apoptosis uses the same binding surface of FADD to trigger signal transduction. A typical model for convergent signal transduction

FADD is known to function as a common signaling conduit in Fas- and tumor necrosis factor (TNF)-mediated apoptosis. The convergent death signals from the Fas receptor and TNF receptor 1 are transferred to FADD by death domain interactions triggering the same cellular event, caspase-8 activation. In this work, we investigated whether the same binding surface of FADD is used for both signaling pathways by using FADD death domain mutants. Mutations in helices alpha2 and alpha3 of the FADD death domain, the interacting surface with the Fas death domain, affected TNF-mediated apoptosis to various extents. This indicated that TNF-mediated apoptosis uses the same binding surface of the FADD death domain as Fas-mediated apoptosis. The binding specificity is not the same, however. Some mutations affected the binding affinity of the Fas death domain for the FADD death domain, but did not influence TNF-mediated apoptosis and vice versa. Interestingly, all mutants tested that affected TNF-mediated apoptosis have structural perturbations, implying that the structural integrity, involving helices alpha2 and alpha3 in particular, is critical in TNF-mediated apoptosis. Our results suggest that different signaling molecules use a similar structural interaction to trigger the same cellular event, such as caspase-8 recruitment, which could be typical in convergent signal transduction.

Accelerated ultraviolet radiation-induced carcinogenesis in hepatocyte growth factor/scatter factor transgenic mice

The dramatic rise in incidence of malignant melanoma experienced by populations both within the United States and throughout the world over the last several decades has been attributed to enhanced exposure to the UV spectrum of sunlight radiation. This hypothesis can now be tested using genetically engineered mouse models predisposed to malignant melanoma. Here we use melanoma-prone transgenic mice inappropriately expressing hepatocyte growth factor/scatter factor (HGF/SF) in the skin as an experimental model system to ascertain the consequences of a chronic regimen of suberythemal UV radiation on melanoma genesis. HGF/SF is a multifunctional regulator capable of stimulating growth, motility, invasiveness, and morphogenetic transformation in cells, including melanocytes, expressing its receptor tyrosine kinase Met. HGF/SF transgenic mice demonstrate ectopic interfollicular localization and accumulation of melanocytes within the truncal dermis, epidermis, and junction and if untreated develop primary cutaneous melanoma with a mean onset age of approximately 21 months. Transgenic mice and their wild-type littermates subjected to UV radiation three times weekly using FS40 sunlamps (60% UVB and 40% UVA), with daily UV doses graded from 2.25 to 6.0 kJ/m2, developed skin tumors with a mean onset age of 26 and 37 weeks, respectively (P < 0.001, Kaplan-Meier log rank test). However, the repeated doses of suberythemal UV radiation used in this study failed to accelerate melanoma genesis, instead inducing the development of nonmelanoma tumors that included squamous cell carcinomas, squamous papillomas, and sarcomas. The conspicuous absence of melanocytic tumors occurred despite the immunohistochemical detection of a significant stimulation (P < 0.001) in melanocyte-specific bromodeoxyuridine incorporation in response to only 2 weeks of UV irradiation (total UV dose of 13.5 kJ/m2), resulting in 2.6- and 4.6-fold increases in the number of melanocytes in the dermis and epidermis, respectively. These data indicate that chronic suberythemal UV radiation preferentially favors the development of nonmelanocytic over melanocytic neoplasms in this transgenic animal, consistent with the pathogenesis proposed for sun exposure-associated skin cancer based on retrospective studies in the human population. Our findings suggest that the HGF/SF transgenic mouse will be useful as an experimental model for determining the consequences of exposure to various regimens of UV radiation and for elucidating the mechanisms by which such consequences are realized.

Death effector domain of a mammalian apoptosis mediator, FADD, induces bacterial cell death

FADD is a mammalian pro-apoptotic mediator consisting of the N-terminal death effector domain (DED) and the C-terminal death domain (DD). The N-terminal 88-residue fragment of murine FADD was defined as the stable structural unit of DED, as determined by proteolytic digestion and conformational analysis. This domain induced bacterial as well as mammalian cell death, whereas the full-length or DD of FADD did not. The Escherichia coli cells expressing FADD-DED showed elongated cell morphology and an increased level of nicked chromosomal DNA and mutation. The lethality of FADD-DED was abolished by co-expression of thioredoxin and superoxide dismutase or relieved by the addition of vitamin E as a reducing agent and under anaerobic growth conditions. The toxicity of FADD-DED was genetically suppressed by various oxidoreductases of E. coli. All these results suggest that the death effector domain of mammalian FADD induced bacterial cell death by enhancing cellular levels of reactive oxygen species (ROS).

The solution structure of FADD death domain. Structural basis of death domain interactions of Fas and FADD

A signal of Fas-mediated apoptosis is transferred through an adaptor protein Fas-associated death domain protein (FADD) by interactions between the death domains of Fas and FADD. To understand the signal transduction mechanism of Fas-mediated apoptosis, we solved the solution structure of a murine FADD death domain. It consists of six helices arranged in a similar fold to the other death domains. The interactions between the death domains of Fas and FADD analyzed by site-directed mutagenesis indicate that charged residues in helices alpha2 and alpha3 are involved in death domain interactions, and the interacting helices appear to interact in anti-parallel pattern, alpha2 of FADD with alpha3 of Fas and vice versa.

Effects of the prostaglandin E2 analogue enprostil on the carbon tetrachloride-induced necrosis of liver cells in mice

Female mice, eight weeks old, were injected with carbon tetrachloride (CCl4) (10 mg subcutaneously). Groups of mice (n = 10-30) were then injected with enprostil (E) 2, 20 or 50 micrograms/kg body weight (bw) intraperitoneally 15 min and two h after, or E 100 micrograms/kg bw two h after the CCl4 injection. The mice were killed after 24, 48 or 72 h. Plasma activity concentrations of alanine aminotransferase (ALAT) were determined in blood specimens from the iliac veins. The extent of liver cell necrosis in histological sections was recorded on a 100 mm Visual Analogue Scale (VAS) and measured using the electronic Mini Mop method. In the group given the highest single dose of E (100 micrograms/kg) a significant lowering of the CCl4-induced liver cell necrosis was found after 24 h. No significant differences were found after 48 and 72 h. In the other groups injected with lower doses of E after CCl4, no significant differences were found compared to groups injected with CCl4 alone.

Implicit and explicit memory in young, old, and demented adults

Previous study of scopolamine and memory (Grober et al., 1989) showed that young adults given moderate or high doses of scopolamine maintained maximum cued recall in spite of a dose-dependent decrement in free recall when memory was assessed by cued selective reminding (CSR), a procedure which circumvents inattention and induces semantic processing. Intact recall by CSR indicates either that scopolamine impairs memory indirectly through effects on attention and information processing or that it impairs explicit memory but not implicit memory. In the present study which was done to determine if CSR reflects explicit or implicit memory, a free association test was used to estimate implicit memory after CSR was administered; explicit memory was estimated with a final trial of cued recall. Data from young, nondemented, and demented adults indicate that CSR reflects explicit memory supporting the interpretation of the previous study that scopolamine does not produce direct impairment of explicit memory.

Validation of a semiquantitative food frequency questionnaire developed in Denmark

In 1989, a self-administered food frequency questionnaire, including 92 food items and 40 portion-size photographs, was validated against two times seven days of weighed diet records. A total of 144 subjects, aged 40-64 years, from the general population in Copenhagen were included. Correlations between mean calorie-adjusted intakes from the two-week diet records and the food-frequency questionnaire ranged from 0.27 for vitamin A to 0.71 for calcium. In general, higher correlation coefficients were observed for men than for women. On average, about 70% of subjects were classified in the same (+/- 1) quintile in the food frequency questionnaire and the diet records. Of those subjects belonging to the lowest quintile, estimated from the diet records, 42% fell in the same quintile and 68% into the lowest two quintiles in the food frequency questionnaire. Findings were similar for the upper tail of the distribution. Gross misclassification, observed in the highest and lowest quintile, was found for 4% and 7% of the subjects, respectively. It is concluded that this food frequency questionnaire is a useful instrument for categorizing individuals according to their intake of nutrients and energy.

Effect of the prostaglandin E1 analogue misoprostol on the carbon tetrachloride-induced injury of rat liver cells in culture

Previous investigators have reported a protective effect of some prostaglandins and of the prostaglandin E2 analogue enprostil on carbon tetrachloride (CCl4)-induced injury of liver cells. In the present study liver cells were isolated from the rat liver by collagenase perfusion and suspended in F-10 medium, containing 20% foetal bovine serum, 1% gentamicin, and 1% glutamine. In the first study cells were cultured in T-flasks with 3 ml suspension of 6 x 10(6) cells/ml, and in the second study (extended dose response) cells were cultured in tissue culture wells with 0.5 ml cell suspension. Misoprostol was added to groups of cultures 15 min before CCl4, 2 microliters/ml, and the number of living cells was counted 45 min after the first addition. The number of living cells was compared with those of other groups with CCl4 only and control groups. In the first experiment misoprostol was given in doses of 200, 400, and 800 ng/ml medium and in the second experiment in 0.1, 1, 10, 100, and 1000 ng/ml medium. CCl4 is an agent well known to be toxic to liver cells, and in cultures to which only CCl4 was added, the number of living cells was significantly reduced compared with controls. When 0.1 ng misoprostol was added before CCl4, no significant difference in the number of living cells was shown compared with cultures with CCl4 only. On the other hand, misoprostol given in doses from 1 ng to 1000 ng before CCl4 resulted in a higher number of living cells, indicating a protective effect.

[The evolution of carboxyhemoglobin during long-term closed-circuit anesthesia]

In 40 patients who underwent protracted orthodontic operations, the accumulation of carboxyhemoglobin (COHb) in the blood was studied. Mechanical ventilation during anesthesia was carried out in a closed system (group I, n = 20). Patients in a control group received mechanical ventilation with a constant fresh gas flow of 6 l/min (group II, n = 20). During closed-system ventilation, a constant rise of COHb was observed. Smokers had much higher COHb values than nonsmokers at the beginning of and during anesthesia. The relative increase of COHb in a defined time period was of the same magnitude for smokers and nonsmokers. Critical values for carbon monoxide (CO) intoxication were not measured. The mean rise was 0.05 g/100 ml COHb over 6 h. Two female patients had COHb rises of 0.29 g/100 ml and 0.18 g/100 ml over the same period. During ventilation with a high flow of fresh gas, the COHb level decreased in all patients. In nonsmokers, the value approached the physiological range of 0.4% to 0.8% COHb. A marked fall of COHb could also be observed in smokers; however, normal physiological values were not reached. Patients with low COHb tolerance (anemia, severe coronary heart disease, peripheral vascular disease) or with increased endogenous CO production (pregnancy, newborns, hemolytic disease, porphyria cutanea) should not undergo protracted ventilation in a closed circle system.

Topographical distribution of fluoride in iliac bone of a fluoride-treated osteoporotic patient

The electron microprobe was used to display the topographical distribution pattern of fluoride (F) at the microscopical level in the iliac bone of an osteoporotic patient treated with fluoride. Composite x-ray image of F K alpha emission revealed a high concentration of fluoride in the periosteal and endosteal bone layers, in the cancellous bone, and in certain osteons, which corresponded to the bone formed during the period of fluoride treatment. Fluoride was also concentrated around the Haversian canals in the vicinity of the capillary blood vessels by a diffusion process. Morphometric analysis showed that more cancellous bone than cortical bone is formed.

Liver cell necrosis and regeneration following injections of carbon tetrachloride. Effects of the thyrotropin-releasing hormone and somatostatin

Mice were given 10 micrograms somatostatin or 25 micrograms TRH intraperitoneally 10 min before s.c. injection of 2 or 20 mg CCl4. The extent of liver cell necrosis and nuclear size were measured by the electronic Mini Mop method and the extent of necrosis and nuclear pleomorphism were estimated by a visual linear analogue scale of 100 mm, and compared to plasma concentrations of ASAT and ALAT. Pre-treatment with TRH or somatostatin resulted in significant reduction in the extent of necrosis 24 h after CCl4-injections (25%), with a lowering of ASAT from 13209 +/- 2955 U/l to 5144 +/- 924 after TRH and to 6186 +/- 966 after somatostatin, and of ALAT from 14343 +/- 3209 to 7718 +/- 1727 and 6494 +/- 1253 U/l, respectively. After 3 days the necroses were reduced from 16.5 +/- 1.7% by the Minimop method to 1.4 +/- 0.5% (90%) in mice given CCl4 alone, and from 12.3 +/- 1.7% to 3.8 +/- 1.2% in mice pretreated with TRH, and from 12.3 +/- 1.8% to 3.8 +/- 1.7% (70%) in mice pretreated with somatostatin. The plasma concentrations of ASAT and ALAT were reduced correspondingly. After 5 days no necroses were seen, and the plasma ASAT and ALAT were normal. After 6 months of weekly injections of TRH or somatostatin before 20 mg CCl4 the liver cell nuclear size (10.5 and 9.7 0.3 mu 2) was similar to that after CCl4 alone (9.7 0.3 mu 2), and twice that of controls (4.6-5.4 0.1 mu 2). Liver cell necrosis was not seen. The plasma concentrations of ASAT (131 8.6-162 11.3) and ALAT (98 8-104 9 Iu/l) were similarly 2-3 times those in controls. TRH and somatostatin thus reduced liver cell injury and delayed regeneration after single injections of CCl4. After 6 months of weekly injections no effects were observed.

Prostaglandins and CCl4-induced liver cell mortality. The effect of the prostaglandin analogue enprostil

Prostaglandins have been reported to reduce the carbon tetrachloride (CCl4)-induced liver cell injury in rats. The object of the present experiments was to examine the effect of the prostaglandin E2 analogue enprostil on the survival of isolated liver cells exposed to CCl4. Liver parenchymal cells were isolated from rat livers by collagenase perfusion and released into a 'suspension' buffer. Aliquots of the cell suspension were incubated with 1 micrograms or 0.5 microgram CCl4, and to parallel test suspensions 20 ng enprostil was added 5-10 min before CCl4. Incubation was performed on ice, at room temperature, and at 37 degrees C. The average percentage of dead cells after CCl4 treatment was significantly reduced by pretreatment with enprostil at room temperature (1 microgram CCl4: 69 +/- 21% and 44 +/- 13%, respectively) and after 10 min of incubation at 37 degrees C (1 microgram Cl4: 56 +/- 25% and 37 +/- 27%; 0.5 microgram CCl4: 51 +/- 33% and 29 +/- 18%, respectively). When the liver cell mortality approximated 100% after long-term incubation at 37 degrees C, no protective effect of enprostil was observed.