Is glycaemic control associated with dietary patterns independent of weight change in people newly diagnosed with type 2 diabetes? Prospective analysis of the Early-ACTivity-In-Diabetes trial

BACKGROUND

It is unclear whether diet affects glycaemic control in type 2 diabetes (T2D), over and above its effects on bodyweight. We aimed to assess whether changes in dietary patterns altered glycaemic control independently of effects on bodyweight in newly diagnosed T2D.

METHODS

We used data from 4-day food diaries, HbA1c and potential confounders in participants of the Early-ACTivity-In-Diabetes trial measured at 0, 6 and 12 months. At baseline, a 'carb/fat balance' dietary pattern and an 'obesogenic' dietary pattern were derived using reduced-rank regression, based on hypothesised nutrient-mediated mechanisms linking dietary intake to glycaemia directly or via obesity. Relationships between 0 and 6 month change in dietary pattern scores and baseline-adjusted HbA1c at 6 months (n = 242; primary outcome) were assessed using multivariable linear regression. Models were repeated for periods 6-12 months and 0-12 months (n = 194 and n = 214 respectively; secondary outcomes).

RESULTS

Reductions over 0-6 months were observed in mean bodyweight (- 2.3 (95% CI: - 2.7, - 1.8) kg), body mass index (- 0.8 (- 0.9, - 0.6) kg/m²), energy intake (- 788 (- 953, - 624) kJ/day), and HbA1c (- 1.6 (- 2.6, -0.6) mmol/mol). Weight loss strongly associated with lower HbA1c at 0-6 months (β = - 0.70 [95% CI - 0.95, - 0.45] mmol/mol/kg lost). Average fat and carbohydrate intakes changed to be more in-line with UK healthy eating guidelines between 0 and 6 months. Dietary patterns shifting carbohydrate intakes higher and fat intakes lower were characterised by greater consumption of fresh fruit, low-fat milk and boiled/baked potatoes and eating less of higher-fat processed meats, butter/animal fats and red meat. Increases in standardised 'carb/fat balance' dietary pattern score associated with improvements in HbA1c at 6 months independent of weight loss (β = - 1.54 [- 2.96, - 0.13] mmol/mol/SD). No evidence of association with HbA1c was found for this dietary pattern at other time-periods. Decreases in 'obesogenic' dietary pattern score were associated with weight loss (β = - 0.77 [- 1.31, - 0.23] kg/SD) but not independently with HbA1c during any period.

CONCLUSIONS

Promoting weight loss should remain the primary nutritional strategy for improving glycaemic control in early T2D. However, improving dietary patterns to bring carbohydrate and fat intakes closer to UK guidelines may provide small, additional improvements in glycaemic control.

TRIAL REGISTRATION

ISRCTN92162869 . Retrospectively registered on 25 July 2005.

Development of a group structured education programme to support safe exercise in people with Type 1 diabetes: the EXTOD education programme

AIM

To develop a structured education programme for individuals with Type 1 diabetes who are engaging in regular exercise.

METHOD

A multidisciplinary team of experts in supporting exercise and physical activity for people with Type 1 diabetes, alongside researchers with experience of developing self-management education, developed an exercise programme using the Medical Research Council framework. The programme was informed by a review of the evidence relating to Type 1 diabetes and exercise, the behaviour change literature (including the behaviour change taxonomy), and qualitative interviews with stakeholders. The programme and supporting resources were refined using an iterative process of testing, delivery and collecting feedback from participants and the wider development team.

RESULTS

The outcome of the intervention development was the design of a feasible and acceptable intervention for people with Type 1 diabetes to support safe exercise. The pilot allowed refinement of the intervention prior to testing in a two-site feasibility randomized controlled trial. Key findings from the pilot informed minor restructuring of the timetable (timings and order) and adaptation of supporting educational materials (participant handbook and teaching materials).

CONCLUSION

The 'EXercise in people with Type One Diabetes' (EXTOD) education programme has been developed using robust methodology for the generation of educational interventions. It now needs testing in a randomized controlled trial.

James Lind Alliance research priorities: should diet and exercise be used as an alternative to drugs for the management of type 2 diabetes or alongside them?

AIM

To review evidence on whether diet and exercise should be used as an alternative to drug therapy for the management of type 2 diabetes or alongside.

METHOD

We present a narrative review that draws on evidence from other systematic reviews and meta-analyses, narrative reviews, trials and cohort studies. We focused mainly on glycaemic control rather than control of blood pressure or cholesterol.

RESULTS

Good-quality dietary advice that results in weight loss of >5% and physical activity interventions of >150 min/week of moderate to vigorous physical activity, combined with resistance exercise, can produce improvements in HbA_1c similar to those produced by the addition of glucose-lowering drugs. These improvements can be seen at all stages of the disease. There are recognized interactions between glucose-lowering drugs and physical activity which may not be synergistic, but these are not well understood, and it is not clear if they are considered in clinical practice. Studies that explicitly compare drugs with diet or physical activity or control for drug use found that lifestyle could delay or reduce medication use, but most people eventually needed to progress to drug treatment. There are few studies, however, that provide strategies for the long-term maintenance of weight loss or physical activity.

CONCLUSION

Diet and physical activity are of key importance in type 2 diabetes management, and attention to them improves glycaemic control and cardiovascular disease risk, but it is not yet known whether maintained lifestyle changes provide an alternative to drug therapy in the long term.

Exercise to preserve β-cell function in recent-onset Type 1 diabetes mellitus (EXTOD) - a randomized controlled pilot trial

AIM

Residual β-cell function is present at the time of diagnosis with Type 1 diabetes. Preserving this β-cell function reduces complications. We hypothesized that exercise preserves β-cell function in Type 1 diabetes and undertook a pilot trial to address the key uncertainties in designing a definitive trial to test this hypothesis.

METHODS

A randomized controlled pilot trial in adults aged 16-60 years diagnosed with Type 1 diabetes within the previous 3 months was undertaken. Participants were assigned to control (usual care) or intervention (exercise consultation every month), in a 1 : 1 ratio for 12 months. The primary outcomes were recruitment rate, drop out, exercise adherence [weeks with ≥ 150 min of self-reported moderate to vigorous physical activity (MVPA)], and exercise uptake in the control group. The secondary outcomes were differences in insulin sensitivity and rate of loss of β-cell function between intervention and control at 6 and 12 months.

RESULTS

Of 507 individuals who were approached, 58 (28 control, 30 intervention) entered the study and 41 completed it. Participants were largely white European males, BMI 24.8 ± 3.8 kg/m² , HbA_1c 75 ± 25 mmol/mol (9 ± 2%). Mean level of objectively measured MVPA increased in the intervention group (mean 243 to 273 min/week) and 61% of intervention participants reached the target of ≥ 150 min/week of self-reported MVPA on at least 42 weeks of the year. Physical activity levels fell slightly in the control group (mean 277 to 235 min of MVPA/week). There was exploratory evidence that intervention group became more insulin sensitive and required less insulin. However, the rate of loss of β-cell function appeared similar between the groups, although the change in insulin sensitivity may have affected this.

CONCLUSION

We show that it is possible to recruit and randomize people with newly diagnosed Type 1 diabetes to a trial of an exercise intervention, and increase and maintain their exercise levels for 12 months. Future trials need to incorporate measures of greater adherence to exercise training targets, and include more appropriate measures of β-cell function. (Clinical Trials Registry No; ISRCTN91388505).

Adaptation of the By-Band randomized clinical trial to By-Band-Sleeve to include a new intervention and maintain relevance of the study to practice

Background

Recruitment into surgical RCTs can be threatened if new interventions available outside the trial compete with those being evaluated. Adapting the trial to include the new intervention may overcome this issue, yet this is not often done in surgery. This paper describes the challenges, rationale and methods for adapting an RCT to include a new intervention.

Methods

The By‐Band study was designed in the UK in 2009–2010 to compare the effectiveness of laparoscopic adjustable gastric band and Roux‐en‐Y gastric bypass for severe obesity. It contained a pilot phase to establish whether recruitment was possible, and the grant proposal specified that an adaptation to include sleeve gastrectomy would be considered if practice changed and recruitment was successful. Information on changing obesity surgery practice, updated evidence and expert opinion about trial design were used to inform the adaptation.

Results

The pilot phase recruited over 13 months in 2013–2014 and randomized 80 patients (79 anticipated). During this time, major changes in obesity practice in the UK were observed, with gastric band reducing from 32·6 to 15·8 per cent and sleeve gastrectomy increasing from 9·0 to 28·1 per cent. The evidence base had not changed markedly. The British Obesity and Metabolic Surgery Society and study oversight committees supported an adaptation to include sleeve gastrectomy, and a proposal to do so was approved by the funder.

Conclusion

Adaptation of a two‐group surgical RCT can allow evaluation of a third procedure and maintain relevance of the RCT to practice. It also optimizes the use of existing trial infrastructure to answer an additional important research question. Registration number: ISRCTN00786323 (http://www.isrctn.com/).

Something to consider

Identification of educational needs in the management of overweight and obesity: results of an international survey of attitudes and practice

Despite the availability of a growing range of interventions to assist control of body weight for people with excess weight or obesity, only a small proportion of people achieve their weight loss goals and are able to maintain body weight reductions in the long term. Negative attitudes and beliefs are often found among physicians and others involved in treating obesity and may adversely impact the effectiveness of management. In this international study, healthcare professionals were invited to complete an online survey of their attitudes and practice in the management of excess body weight. A total of 335 clinicians completed the survey of whom approximately half were based in Europe. A key finding from the survey is that, while participants are generally confident in their ability to manage overweight and obesity effectively, they also report that most of their patients are not successful in achieving their weight loss goals. At the same time, participants tended to overestimate the effectiveness of current medical management in maintaining reductions in body weight. Educational initiatives addressing the real-life effectiveness of different weight control interventions may help to close the gap between clinicians' perceptions and reality in the management of excess body weight.

Outcome reporting in bariatric surgery: an in-depth analysis to inform the development of a core outcome set, the BARIACT Study

Outcome reporting in bariatric surgery needs a core outcome set (COS), an agreed minimum set of outcomes reported in all studies of a particular condition. The aim of this study was to summarize outcome reporting in bariatric surgery to inform the development of a COS. Outcomes reported in randomized controlled trials (RCTs) and large non-randomized studies identified by a systematic review were listed verbatim and categorized into domains, scrutinizing the frequency of outcome reporting and uniformity of definitions. Ninety studies (39 RCTs) identified 1,088 separate outcomes, grouped into nine domains with most (n = 920, 85%) reported only once. The largest outcome domain was 'surgical complications', and overall, 42% of outcomes corresponded to a theme of 'adverse events'. Only a quarter of outcomes were defined, and where provided definitions, which were often contradictory. Percentage of excess weight loss was the main study outcome in 49 studies, but nearly 40% of weight loss outcomes were heterogeneous, thus not comparable. Outcomes of diverse bariatric operations focus largely on adverse events. Reporting is inconsistent and ill-defined, limiting interpretation and comparison of published studies. Thus, we propose and are developing a COS for the surgical treatment of severe and complex obesity.

Sedentary time and markers of inflammation in people with newly diagnosed type 2 diabetes

BACKGROUND AND AIMS

We investigated whether objectively measured sedentary time was associated with markers of inflammation in adults with newly diagnosed type 2 diabetes.

METHODS AND RESULTS

We studied 285 adults (184 men, 101 women, mean age 59.0 ± 9.7) who had been recruited to the Early ACTivity in Diabetes (Early ACTID) randomised controlled trial. C-reactive protein (CRP), adiponectin, soluble intracellular adhesion molecule-1 (sICAM-1), interleukin-6 (IL-6), and accelerometer-determined sedentary time and moderate-vigorous physical activity (MVPA) were measured at baseline and after six-months. Linear regression analysis was used to investigate the independent cross-sectional and longitudinal associations of sedentary time with markers of inflammation. At baseline, associations between sedentary time and IL-6 were observed in men and women, an association that was attenuated following adjustment for waist circumference. After 6 months of follow-up, sedentary time was reduced by 0.4 ± 1.2 h per day in women, with the change in sedentary time predicting CRP at follow-up. Every hour decrease in sedentary time between baseline and six-months was associated with 24% (1, 48) lower CRP. No changes in sedentary time between baseline and 6 months were seen in men.

CONCLUSIONS

Higher sedentary time is associated with IL-6 in men and women with type 2 diabetes, and reducing sedentary time is associated with improved levels of CRP in women. Interventions to reduce sedentary time may help to reduce inflammation in women with type 2 diabetes.

Dietary changes and associations with metabolic improvements in adults with type 2 diabetes during a patient-centred dietary intervention: an exploratory analysis

OBJECTIVES

Describe dietary intake of participants enrolled in a non-prescriptive dietary intervention and dietary changes at 6 months and explore whether these changes had a role in observed improvements in glycated haemoglobin (HbA1c), weight, lipids and blood pressure.

DESIGN

Secondary analysis of data from the Early ACTivity in Diabetes randomised controlled trial.

PARTICIPANTS

262 patients with newly diagnosed type 2 diabetes randomised to the dietary intervention.

OUTCOMES AND ANALYSIS

Changes in energy intake, macronutrients, fibre and alcohol and in weight, waist circumference, lipids, HbA1c and blood pressure at baseline and 6 months. Multivariate models were used to examine associations between dietary changes and metabolic variables.

RESULTS

Men reported reducing mean energy intake from 1903±462 kcal to 1685 kcal±439 kcal (p<0.001), increasing carbohydrate intake from 42.4±6.6% to 43.8±6.6% (p=0.002) and reducing median alcohol intake from 13 (0-27) g to 5 (0-18) g (p<0.001). Women reported reducing mean energy intake from 1582±379 kcal to 1459±326 kcal (p<0.001) with no change to macronutrient distribution and alcohol. Fibre intake was maintained. In men (n=148), weak and clinically insignificant associations were found between increased carbohydrates and reduction in HbA1c (β=-0.003 (-0.006, -0.001); p=0.009), increased fibre and reduction in total cholesterol (β=-0.023 (-0.044, -0.002); p=0.033), decreased total fat and reduction in low-density lipoprotein (LDL)-cholesterol (β=0.024 (0.006, 0.001); p=0.011), and decreased alcohol and reduction in diastolic blood pressure (β=0.276 (0.055, 0.497); p=0.015). In women (n=75), associations were found between a decrease in transfats and reductions in waist circumference (β=-0.029 (0.006, 0.052); p=0.015), total cholesterol (β=0.399 (0.028, 0.770); p=0.036) and LDL cholesterol (β=0.365 (0.042, 0.668); p=0.028).

CONCLUSIONS

Clinically important metabolic improvements observed in a patient-centred dietary intervention were not explained by changes in macronutrients. However, a non-prescriptive approach may promote a reduction in total energy intake while maintaining fibre consumption.

TRIAL REGISTRATION NUMBER

The Early ACTID trial number ISRCTN92162869.

Patient-reported outcomes in bariatric surgery: a systematic review of standards of reporting

Bariatric surgery is increasingly being used to treat severe obesity, but little is known about its impact on patient-reported outcomes (PROs). For PRO data to influence practice, well-designed and reported studies are required. A systematic review identified prospective bariatric surgery studies that used validated PRO measures. Risk of bias in randomized controlled trials (RCTs) was assessed, and papers were examined for reporting of (i) who completed PRO measures; (ii) missing PRO data and (iii) clinical interpretation of PRO data. Studies meeting all criteria were classified as robust. Eighty-six studies were identified. Of the eight RCTs, risk of bias was high in one and unclear in seven. Sixty-eight different PRO measures were identified, with the Short Form (SF)-36 questionnaire most commonly used. Forty-one (48%) studies explicitly stated measures were completed by patients, 63 (73%) documented missing PRO data and 50 (58%) interpreted PRO data clinically. Twenty-six (30%) met all criteria. Although many bariatric surgery studies assess PROs, study design and reporting is often poor, limiting data interpretation and synthesis. Well-designed studies that include agreed PRO measures are needed with reporting to include integration with clinical outcomes to inform practice.

Sedentary time, breaks in sedentary time and metabolic variables in people with newly diagnosed type 2 diabetes

AIMS/HYPOTHESIS

We investigated whether objectively measured sedentary time and interruptions in sedentary time are associated with metabolic factors in people with type 2 diabetes.

METHODS

We studied 528 adults (30-80 years) with newly diagnosed type 2 diabetes, who were participants in a diet and physical activity intervention. Waist circumference (WC), fasting HDL-cholesterol, insulin and glucose levels, HOMA of insulin resistance (HOMA-IR) and physical activity (accelerometer) were measured at baseline and at 6 months follow-up. Linear regression models were used to investigate cross-sectional and longitudinal associations of accelerometer-derived sedentary time and breaks in sedentary time (BST) with metabolic variables.

RESULTS

In cross-sectional analyses each hour of sedentary time was associated with larger WC (unstandardised regression coefficient [B] [95% CI] 1.89 cm [0.94, 2.83]; p < 0.001), higher insulin (B = 8.22 pmol/l [2.80, 13.65]; p = 0.003) and HOMA-IR (B = 0.42 [0.14, 0.70]; p = 0.004), and lower HDL-cholesterol (B = -0.04 mmol/l [-0.06, -0.01]; p = 0.005). Adjustment for WC attenuated all associations. Each BST was associated with lower WC (B = -0.15 cm [- 0.24, -0.05]; p = 0.003) and there was evidence of a weak linear association with HDL-cholesterol, but no association with insulin levels or HOMA-IR. Volume of sedentary time at baseline predicted HDL-cholesterol (B = -0.05 mmol/l [-0.08, -0.01]; p = 0.007), insulin levels (B = 8.14 pmol/l [0.1.51, 14.78]; p = 0.016) and HOMA-IR (B = 0.49 [0.08, 0.90]; p = 0.020) at 6 months, though not WC. Baseline BST did not substantially predict any metabolic variables at follow-up. No change was seen in sedentary time or BST between baseline and 6 months follow-up.

CONCLUSIONS/INTERPRETATION

Higher sedentary time is associated with a poorer metabolic profile in people with type 2 diabetes.

Diet or diet plus physical activity versus usual care in patients with newly diagnosed type 2 diabetes: the Early ACTID randomised controlled trial

BACKGROUND

Lifestyle changes soon after diagnosis might improve outcomes in patients with type 2 diabetes mellitus, but no large trials have compared interventions. We investigated the effects of diet and physical activity on blood pressure and glucose concentrations.

METHODS

We did a randomised, controlled trial in southwest England in adults aged 30-80 years in whom type 2 diabetes had been diagnosed 5-8 months previously. Participants were assigned usual care (initial dietary consultation and follow-up every 6 months; control group), an intensive diet intervention (dietary consultation every 3 months with monthly nurse support), or the latter plus a pedometer-based activity programme, in a 2:5:5 ratio. The primary endpoint was improvement in glycated haemoglobin A(1c)(HbA(1c)) concentration and blood pressure at 6 months. Analysis was done by intention to treat. This study is registered, number ISRCTN92162869.

FINDINGS

Of 593 eligible individuals, 99 were assigned usual care, 248 the diet regimen, and 246 diet plus activity. Outcome data were available for 587 (99%) and 579 (98%) participants at 6 and 12 months, respectively. At 6 months, glycaemic control had worsened in the control group (mean baseline HbA(1c) percentage 6·72, SD 1·02, and at 6 months 6·86, 1·02) but improved in the diet group (baseline-adjusted difference in percentage of HbA(1c) -0·28%, 95% CI -0·46 to -0·10; p=0·005) and diet plus activity group (-0·33%, -0·51 to -0·14; p<0·001). These differences persisted to 12 months, despite less use of diabetes drugs. Improvements were also seen in bodyweight and insulin resistance between the intervention and control groups. Blood pressure was similar in all groups.

INTERPRETATION

An intensive diet intervention soon after diagnosis can improve glycaemic control. The addition of an activity intervention conferred no additional benefit.

FUNDING

Diabetes UK and the UK Department of Health.

Biostability and disinfectant by-product formation in drinking water blended with UF-treated filter backwash water

The overall objective of this study was to investigate the impact of blending membrane-treated water treatment plant (WTP) residuals with plant-filtered water on finished water quality in terms of biostability and disinfectant by-product (DBP) formation. Filter backwash water (FBWW) was treated with a pilot-scale ultrafiltration (UF) membrane to produce permeate that was blended with plant-finished water. The batch studies involved storing samples for a specified time with a disinfectant residual to simulate residence time in the distribution system. Both chlorinated and non-chlorinated FBWW streams were evaluated, and the experimental design incorporated free chlorine, monochloramine, and chlorine dioxide in parallel to a model system that did not receive a disinfectant dose. The results of the study found that blending 10% UF-treated FBWW with plant-filtered water did not have an impact on water biostability as monitored with heterotrophic plate counts (HPCs) or DBP concentrations as monitored by TTHM and HAA5 concentrations. However, the presence of preformed THM and HAA species found in chlorinated FBWW streams may result in higher levels of initial DBP concentrations in blended water matrices, and could have a significant impact on finished water quality in terms of meeting specific DBP guidelines or regulations.

A field study evaluation for mitigating biofouling with chlorine dioxide or chlorine integrated with UV disinfection

The drinking water industry is continually seeking innovative disinfection strategies to control biofouling in transmission systems. This research, conducted in collaboration with the East Bay Municipal Utility District (EBMUD) in California, compared the efficacy of chlorine dioxide (ClO2) to free chlorine (Cl2) with and without pre-treatment with low-pressure ultraviolet (UV) light for biofilm control. An additional goal was to determine disinfection by-product (DBP) formation with each disinfection strategy. Annular reactors (ARs) containing polycarbonate coupons were used to simulate EBMUD's 90-mile aqueduct that transports surface water from a source reservoir to treatment facilities. ARs were dosed with chemical disinfectants to achieve a residual of 0.2 mg/L, which is a typical value mid-way in the aqueduct. The experiment matrix included four strategies of disinfection including UV/ClO2, ClO2, UV/Cl2 and Cl2. Two ARs acted as controls and received raw water (RW) or UV-treated water. The data presented show that the UV/ClO2 combination was most effective against suspended and attached heterotrophic (heterotrophic plate count, HPC) bacteria with 3.93 log and 2.05 log reductions, respectively. ClO2 was more effective than Cl2 at removing suspended HPC bacteria and similarly effective in biofilm bacterial removal. UV light alone was not effective in controlling suspended or biofilm bacteria compared to treatment with ClO2 or Cl2. Pre-treatment with UV was more effective overall for removal of HPC bacteria than treating with corresponding chemical disinfectants only; however, it did not lower required chemical dosages. Therefore, no significant differences were observed in DBP concentrations between ARs pre-treated with UV light and ARs not pre-treated. Disinfection with ClO2 produced fewer total trihalomethanes (TTHMs) and haloacetic acids (HAAs) than chlorination but did produce low levels of chlorite. These data indicate that replacing Cl2 with ClO2 would further control microbiological re-growth and minimize TTHM and HAA formation, but may introduce other DBPs.

Impact of iron particles in groundwater on the UV inactivation of bacteriophages MS2 and T4

AIMS

To investigate the impact of iron particles in groundwater on the inactivation of two model viruses, bacteriophages MS2 and T4, by 254-nm ultraviolet (UV) light.

METHODS AND RESULTS

One-litre samples of groundwater with high iron content (from the Indianapolis Water Company, mean dissolved iron concentration 1.3 mg l(-1)) were stirred vigorously while exposed to air, which oxidized and precipitated the dissolved iron. In parallel samples, ethylenediaminetetra-acetic acid (EDTA) was added to chelate the iron and prevent formation of iron precipitate. The average turbidity in the samples without EDTA (called the 'raw' samples) after 210 min of stirring was 2.7 +/- 0.1 NTU while the average turbidity of the samples containing EDTA (called the 'preserved' samples) was 1.0 +/- 0.1 NTU. 'Raw' and 'preserved' samples containing bacteriophage MS2 were exposed to 254-nm UV light at doses of 20, 40, or 60 mJ (cm(2))(-1), while samples containing bacteriophage T4 were exposed to 2 or 5 mJ (cm(2))(-1), using a low pressure UV collimated beam. The UV inactivation of both phages in the 'raw' groundwater was lower than in the EDTA-'preserved' groundwater to a statistically significant degree (alpha = 0.05), due to the association of phage with the UV-absorbing iron precipitate particles. A phage elution technique confirmed that a large fraction of the phage that survived the UV exposures were particle-associated.

CONCLUSIONS

Phages that are associated with iron oxide particles in groundwater are shielded from UV light to a measurable and statistically significant degree at a turbidity level of 2.7 NTU when the phage particle association is induced under experimental conditions.

SIGNIFICANCE AND IMPACT OF THE STUDY

While the particle association of the phage in this study was induced experimentally, the findings provide further evidence that certain particles in natural waters and wastewaters (e.g. iron oxide particles) may have the potential to shield viruses from UV light.

Effect of disinfectants on microbial ecology in model distribution systems

This research was conducted to assess the impact of various disinfectants on bacterial water quality within model distribution systems (i.e. annular reactors). After colonization with non-disinfected water, annular reactors were treated with relatively low doses of chlorine (0.4 mg/l), chlorine dioxide (0.15 mg/l), or chloramines (0.9 mg/l). Under the tested conditions, bacterial inactivation varied as a function of disinfectant type (ranking by efficiency per mg of oxidant: ClO2 > Cl2 > ClNH2) and sample type (bulk water vs. biofilm). Depending on the disinfectant, the log inactivation of suspended and attached bacteria were 0.7-1.2 and 0.5-1.0, respectively. The characterization of microbial communities in drinking water can be performed using biochemical and/or molecular methods. In this study, biochemical tests were used, showing that pseudomonad and pseudomonad-like bacteria, as in other studies, were the most predominant micro-organisms (e.g. Pseudomonas fluorescens, Brevundimonas vescularis). The ratio Gram-positive to Gram-negative organisms was 1 to 3. No drastic differences were observed between the non-treated and disinfected pipes. Based on the bacteriological data presented in these experiments, chlorine dioxide represents an alternative to chlorine for certain distribution systems.

Disinfectant efficacy of chlorite and chlorine dioxide in drinking water biofilms

The drinking water industry is closely examining options to maintain disinfection in distribution systems. In particular this research compared the relative efficiency of the chlorite ion (ClO2-) to chlorine dioxide (ClO2) for biofilm control. Chlorite levels were selected for monitoring since they are typically observed in the distribution system as a by-product whenever chlorine dioxide is applied for primary or secondary disinfection. Previous research has reported the chlorite ion to be effective in mitigating nitrification in distribution systems. Annular reactors (ARs) containing polycarbonate and cast iron coupons were used to simulate water quality conditions in a distribution system. Following a 4 week acclimation period, individual ARs operated in parallel were dosed with high (0.25mg/l) and low (0.1mg/l) chlorite concentrations and with high (0.5 mg/l) and low (0.25mg/l) chlorine dioxide concentrations, as measured in the effluent of the AR. Another set of ARs that contained cast iron and polycarbonate coupons served as controls and did not receive any disinfection. The data presented herein show that the presence of chlorite at low concentration levels was not effective at reducing heterotrophic bacteria. Log reductions of attached heterotrophic bacteria for low and high chlorite ranged between 0.20 and 0.34. Chlorine dioxide had greater log reductions for attached heterotrophic bacteria ranging from 0.52 to 1.36 at the higher dose. The greatest log reduction in suspended heterotrophic bacteria was for high dose of ClO2 on either cast iron or polycarbonate coupons (1.77 and 1.55). These data indicate that it would be necessary to maintain a chlorine dioxide residual concentration in distribution systems for control of microbiological regrowth.

Design of selective and soluble inhibitors of tumor necrosis factor-alpha converting enzyme (TACE)

A program to improve upon the in vitro, in vivo, and physicochemical properties of N-hydroxyformamide TACE inhibitor GW 3333 (1) is described. Using the primary structure of pro-TNF-alpha, along with a homology model of the catalytic domain of TACE based on the X-ray diffraction coordinates of adamalysin, we synthesized N-hydroxyformamide TACE inhibitors containing a P2' arginine side chain. Introduction of nitro and sulfonyl electron-withdrawing groups covalently bound to the P2' guanidine moiety rendered the inhibitors electronically neutral at cellular pH and led to potent inhibition of TNF-alpha release from stimulated macrophages. Inhibitors containing these arginine mimetics were found to have increased solubility in simulated gastric fluid (SGF) relative to 1, allowing for the incorporation of lipophilic P1' side chains which had the effect of retaining potent TACE inhibition, but reducing potency against matrix metalloproteases (MMPs) thus increasing overall selectivity against MMP1, MMP3, and MMP9. Selected compounds showed good to excellent in vivo TNF inhibition when administered via subcutaneous injection. One inhibitor, 28a, with roughly 10x selectivity over MMP1 and MMP3 and high solubility in SGF, was evaluated in the rat zymosan-induced pleuisy model of inflammation and found to inhibit zymosan-stimulated pleural TNF-alpha elevation by 30%.

Inhibition of tumor necrosis factor-alpha (TNF-alpha) production and arthritis in the rat by GW3333, a dual inhibitor of TNF-alpha-converting enzyme and matrix metalloproteinases

Tumor necrosis factor-alpha (TNF)-converting enzyme (TACE) cleaves the precursor form of TNF, allowing the mature form to be secreted into the extracellular space. GW3333, a dual inhibitor of TACE and matrix metalloproteinases (MMPs), was compared with an anti-TNF antibody to evaluate the importance of soluble TNF and MMPs in rat models of arthritis. Oral administration of GW3333 completely blocked increases in plasma TNF after LPS for up to 12 h. In a model wherein intrapleural zymosan injection causes an increase in TNF in the pleural cavity, GW3333 completely inhibited the increase in TNF in the pleural cavity for 12 h. Under these dosing conditions, the plasma levels of unbound GW3333 were at least 50-fold above the IC(50) values for inhibition of individual MMPs in vitro. In a model wherein bacterial peptidoglycan polysaccharide polymers reactivate a local arthritis response in the ankle, a neutralizing anti-TNF antibody completely blocked the ankle swelling over the 3-day reactivation period. GW3333 administered b.i.d. over the same period also inhibited ankle swelling, with the highest dose of 80 mg/kg being slightly less active than the anti-TNF antibody. In a 21-day adjuvant arthritis model, the anti-TNF antibody did not inhibit the ankle swelling or the joint destruction, as assessed by histology or radiology. GW3333, however, showed inhibition of both ankle swelling and joint destruction. In conclusion, GW3333 is the first inhibitor with sufficient duration of action to chronically inhibit TACE and MMPs in the rat. The efficacy of GW3333 suggests that dual inhibitors of TACE and matrix metalloproteinases may prove therapeutic as antiarthritics.

N-hydroxyformamide peptidomimetics as TACE/matrix metalloprotease inhibitors: oral activity via P1' isobutyl substitution

N-Hydroxyformamide-class metalloprotease inhibitors were designed and synthesized, which have potent broad-spectrum activity versus matrix metalloproteases and TNF-alpha converting enzyme (TACE). Compound 13c possesses good oral and intravenous pharmacokinetics in the rat and dog.

Chlorine dioxide inactivation of Cryptosporidium parvum oocysts and bacterial spore indicators

Cryptosporidium parvum, which is resistant to chlorine concentrations typically used in water treatment, is recognized as a significant waterborne pathogen. Recent studies have demonstrated that chlorine dioxide is a more efficient disinfectant than free chlorine against Cryptosporidium oocysts. It is not known, however, if oocysts from different suppliers are equally sensitive to chlorine dioxide. This study used both a most-probable-number-cell culture infectivity assay and in vitro excystation to evaluate chlorine dioxide inactivation kinetics in laboratory water at pH 8 and 21 degrees C. The two viability methods produced significantly different results (P < 0.05). Products of disinfectant concentration and contact time (Ct values) of 1,000 mg. min/liter were needed to inactivate approximately 0.5 log(10) and 2.0 log(10) units (99% inactivation) of C. parvum as measured by in vitro excystation and cell infectivity, respectively, suggesting that excystation is not an adequate viability assay. Purified oocysts originating from three different suppliers were evaluated and showed marked differences with respect to their resistance to inactivation when using chlorine dioxide. Ct values of 75, 550, and 1,000 mg. min/liter were required to achieve approximately 2.0 log(10) units of inactivation with oocysts from different sources. Finally, the study compared the relationship between easily measured indicators, including Bacillus subtilis (aerobic) spores and Clostridium sporogenes (anaerobic) spores, and C. parvum oocysts. The bacterial spores were found to be more sensitive to chlorine dioxide than C. parvum oocysts and therefore could not be used as direct indicators of C. parvum inactivation for this disinfectant. In conclusion, it is suggested that future studies address issues such as oocyst purification protocols and the genetic diversity of C. parvum, since these factors might affect oocyst disinfection sensitivity.

Endothelium-derived hyperpolarizing factor and potassium use different mechanisms to induce relaxation of human subcutaneous resistance arteries

This investigation examined the hypothesis that release of K(+) accounts for EDHF activity by comparing relaxant responses produced by ACh and KCl in human subcutaneous resistance arteries. Resistance arteries (internal diameter 244+/-12 microm, n=48) from human subcutaneous fat biopsies were suspended in a wire myograph. Cumulative concentration-response curves were obtained for ACh (10(-9) - 3x10(-5) M) and KCl (2.5 - 25 mM) following contraction with noradrenaline (NA; 0.1 - 3 microM). ACh (E(max) 99.07+/-9.61%; -LogIC(50) 7.03+/-0.22; n=9) and KCl (E(max) 74.14+/-5.61%; -LogIC(50) 2.12+/-0.07; n=10)-induced relaxations were attenuated (P<0.0001) by removal of the endothelium (E(max) 8.21+/-5.39% and 11.56+/-8.49%, respectively; n=6 - 7). Indomethacin (10 microM) did not alter ACh-induced relaxation whereas L-NOARG (100 microM) reduced this response (E(max) 61.7+/-3.4%, P<0.0001; n=6). The combination of ChTx (50 nM) and apamin (30 nM) attenuated the L-NOARG-insensitive component of ACh-induced relaxation (E(max): 15.2+/-10.5%, P<0.002, n=6) although these arteries retained the ability to relax in response to 100 microM SIN-1 (E(max) 127.6+/-13.0%, n=3). Exposure to BaCl(2) (30 microM) and Ouabain (1 mM) did not attenuate the L-NOARG resistant component of ACh-mediated relaxation (E(max), 76.09+/-8.92, P=0.16; n=5). KCl-mediated relaxation was unaffected by L-NOARG+indomethacin (E(max); 68.1+/-5.6%, P=0.33; n=5) or the combination of L-NOARG/indomethacin/ChTx/apamin (E(max); 86.61+/-14.02%, P=0.35; n=6). In contrast, the combination of L-NOARG, indomethacin, ouabain and BaCl(2) abolished this response (E(max), 5.67+/-2.59%, P<0.0001, n=6). The characteristics of KCl-mediated relaxation differed from those of the nitric oxide/prostaglandin-independent component of the response to ACh, and were endothelium-dependent, indicating that K(+) does not act as an EDHF in human subcutaneous resistance arteries.

Ammoniacal bromamines: a review of their influence on bromate formation during ozonation

Ammonia can inhibit the formation of bromate in ozonated drinking water by reacting with free bromine (HOBr/OBr-), an intermediate in bromate formation, to form bromamines. Bromamines do not participate in bromate formation, however, they will decay due to autonomous decomposition and through reaction with ozone and hydroxyl radicals. The reaction with ozone controls the overall decay rate. This reaction also results in a net loss of ammonia from the system, leading to the possibility that all ammonia may be oxidized before the ozone residual in the water is eliminated, allowing bromate formation to resume. This paper presents a review of our understanding of bromamine chemistry and identifies areas that are not adequately understood, which may prevent an accurate estimation of ammonia's impact on bromate formation.

Cortisol metabolism in healthy young adults: sexual dimorphism in activities of A-ring reductases, but not 11beta-hydroxysteroid dehydrogenases

Cortisol is metabolized irreversibly by A-ring reductases (5alpha- and 5beta-reductases) and reversibly (to cortisone) by 11beta-hydroxysteroid dehydrogenases (11betaHSDs). In rats, estradiol down-regulates 11betaHSD1 expression. In humans, ratios of urinary cortisol/cortisone metabolites differ in men and women. In this study, urinary cortisol metabolites and hepatic 11betaHSD1 activity were measured in healthy young men and women at different phases of the menstrual cycle. Ten men and 10 women with regular menstrual cycles collected a 24-h urine sample, took 250 microg oral dexamethasone at 2300 h, took 25 mg oral cortisone at 0900 h (after fasting), and had blood sampled for plasma cortisol estimation over the subsequent 150 min. Women repeated the tests in random order in menstrual, follicular, and luteal phases. Women excreted disproportionately less A-ring-reduced metabolites of cortisol [median 5alpha-tetrahydrocortisol, 1811 (interquartile range, 1391-2300) microg/day in menstrual phase vs. 2723 (interquartile range, 2454-3154) in men (P = 0.01); 5beta-tetrahydrocortisol, 1600 (interquartile range, 1419-1968) vs. 2197 (interquartile range, 1748-2995; P = 0.03)] but similar amounts of cortisol, cortisone, and tetrahydrocortisone. Analogous differences were observed in urinary excretion of androgen metabolites. Conversion of cortisone to cortisol on hepatic first pass metabolism was not different (peak plasma cortisol, 733 +/- 60 nmol/L in women vs. 684 +/- 53 nmol/L in men; mean +/- SEM; P = 0.55). There were no differences in cortisol or androgen metabolism between phases of the menstrual cycle. We conclude that sexual dimorphism in cortisol metabolite excretion is attributable to less A-ring reduction of cortisol in women, rather than less reactivation of cortisone to cortisol by 11betaHSD1. This difference is not influenced acutely by gonadal steroids. 11BetaHSD1 has been suggested to modulate insulin sensitivity and body fat distribution, but caution must be exercised in extrapolating inferences about its regulation from rodents to man. A-Ring reductases may have an equally important influence on metabolic clearance of cortisol and intracellular cortisol concentrations.

Glucocorticoids and insulin resistance: old hormones, new targets

Insulin resistance has been proposed as a mediator of the association between risk factors for cardiovascular disease in the population. The clinical syndrome of glucocorticoid excess (Cushing's syndrome) is associated with glucose intolerance, obesity and hypertension. By opposing the actions of insulin, glucocorticoids could contribute to insulin resistance and its association with other cardiovascular risk factors. In this review, we describe briefly the known mechanisms of insulin resistance and highlight the potential mechanisms for the effect of glucocorticoids. We then discuss factors which modulate the influence of glucocorticoids on insulin sensitivity; this highlights a novel therapeutic strategy to manipulate glucocorticoid action which may prove to be a useful tool in treating subjects with insulin resistance. Finally, we describe evidence from human studies that glucocorticoids make an important contribution to the pathophysiology of insulin resistance in the population.

Discovery of bioavailable inhibitors of secretory phospholipase A2

Substrate-mimetic inhibitors of sPLA2 with submicromolar in vitro potency were discovered by use of a novel dual substrate screening strategy. In vivo evaluation of selected inhibitors in the rat carrageenan paw edema model of inflammation, however, indicated that in vitro potency was not a good predictor of in vivo activity. Studies of the metabolic stability of early examples of these inhibitors suggested that the metabolic lability of these compounds was a major contributing factor to the observed weak in vivo activity. In an attempt to achieve improved in vivo activity, we prepared and tested compounds designed to overcome the observed metabolic instability. The design of the new compounds involved two types of changes in the inhibitor molecules. First, the C-2 ester moiety was replaced with an amide function so that direct cleavage by stomach acid and blood esterases at this site was minimized. Second, omega-oxidation of the decanamide moiety was eliminated by substitution of hydrogen with fluorine in this position. Compounds containing fluorine in the terminal positions of the alkyl chain retained sPLA2 inhibitory activity and also possessed improved in vitro metabolic stability and pharmacokinetic parameters relative to nonfluorinated inhibitors in this series. As exemplified by GW 4776, improvements in metabolic stability alone, however, were not sufficient to ensure oral activity. Thus, GW 4776 did not show oral activity in the carrageenan edema model and had only modest activity after i.v. dosing in the same model. In fact, the results for GW 9624 and GW 8219 suggested that factors in addition to potency of sPLA2 inhibition and metabolism affect the observed in vivo activity. Despite the fact that these two compounds varied only by a single oxygen-to-sulfur substitution, one was active whereas the other was not. One possible explanation for the observed variability is a compound-dependent difference in the rate of equilibration into tissue. This possibility is relevant as both the carrageenan paw edema model and the phorbol ester edema model involve a localized inflammation. No measurements were made to assess differences in the distribution of the different inhibitors between the blood and the localized site of inflammation. In summary, a series of bioavailable inhibitors of sPLA2 was prepared using an iterative approach that combined medicinal chemistry, in vitro and in vivo evaluation of biological activity, and metabolic and pharmacokinetic studies. Although some compounds in the series showed in vivo activity, the anti-inflammatory effect observed in animal models was modest and a decision was made to abandon sPLA2 as a molecular target for the development of anti-inflammatory agents.

Substrate specificity in short-chain phospholipid analogs at the active site of human synovial phospholipase A2

The substrate specificity at the active site of recombinant human synovial fluid phospholipase A2 (hs-PLA2) was investigated by the preparation of a series of short-chain phospholipid analogs and measurement of their enzymatic hydrolysis at concentrations well below the critical micelle concentration. Substrates used in the study included 1,2-dihexanoylglycerophospholipids, 1,2-bis(alkanoylthio)glycerophospholipids, and 1-O-alkyl-2-(alkanoylthio)phospholipids. Turnover was observed for only a few of the 1,2-dihexanoylglycerophospholipids, and the rate of hydrolysis was very low, near the limit of detection of the assay. In contrast, selected 2-(alkanoylthio)-glycerophospholipids were hydrolyzed by hs-PLA2 at much higher rates at concentrations well below their critical micelle concentration (cmc). Thus, the 1,2-bis(hexanoylthio)glycerophosphatidylmethanol exhibits a k(cat)/K(M) = 1800 L mol-1 s-1. Over the calculated log P (cLogP) range of 3-9, cLogP and log(k(cat)/K(M) were linearly related for compounds with straight-chain sn-1 and sn-2 substituents. At comparable cLogP's, the sn-1 ethers and thioesters were hydrolyzed at comparable rates. A negative charge in the phosphate head group was required for enzyme activity. Unsaturation, aromaticity, and branching in the sn-2 substituent reduce turnover dramatically. The same structural modifications in the sn-1 substituent have less effect on turnover. Certain of these substrates, e.g., 1,2-bis(hexanoylthio)glycerophosphatidylmethanol, may be useful in assaying for active site inhibitors of PLA2. The structure--activity relationships established here for substrates should serve as a reference for the structure--activity relationships of substrate-based inhibitors.

6-Azasteroids: structure-activity relationships for inhibition of type 1 and 2 human 5 alpha-reductase and human adrenal 3 beta-hydroxy-delta 5-steroid dehydrogenase/3-keto-delta 5-steroid isomerase

6-Azaandrost-4-en-3-ones were synthesized and tested versus human type 1 and 2 steroid 5 alpha-reductase (5AR) and human adrenal 3 beta-hydroxy-delta 5-steroid dehydrogenase/3-keto-delta 5-steroid isomerase (3BHSD) to explore the structure-activity relationship of this novel series in order to optimize potency versus both isozymes of 5AR and selectivity versus 3BHSD. Compounds with picomolar IC50's versus human type 2 5AR and low nanomolar Ki's versus human type 1 5AR with 100-fold selectivity versus 3BHSD were identified (70). Preliminary in vivo evaluation of some optimal compounds from this series in a chronic castrated rat model of 5AR inhibitor-induced prostate involution and dog pharmacokinetic measurements identified a series of 17 beta-[N-(diphenylmethyl)carbamoyl]-6-azaandrost-4-en-3-ones (compounds 54, 66, and 67) with good in vivo efficacy and half-life in the dog. Inhibitors with, at the minimum, low nanomolar potency toward both human 5AR's and selectivity versus 3BHSD may show advantages over previously known 5AR inhibitors in the treatment of disease states which depend upon dihydrotestosterone, such as benign prostatic hyperplasia.

An update of the zinc deficiency theory of schizophrenia. Identification of the sex determining system as the site of action of reproductive zinc deficiency

The following article updates the GZD theory of schizophrenia (1) by showing that male transmission of risk, the parental age effect, racial differences in birth seasonality, the disturbed sex ratios in the offspring of schizophrenic mothers and the association between diabetes and schizophrenia are explained by changes to zinc homeostasis. A genetic component to the disorder is now seen as unnecessary, transmission of risk by either parent, and twin concordance differences can be explained by other means. The primary site of action of GZD is identified as the putative ZFY sex determining system. Evidence suggesting that other mental disorders might be caused by GZD is also discussed.

Unification of the findings in schizophrenia by reference to the effects of gestational zinc deficiency

The hypothesis presented here suggests that schizophrenia is caused by the action of gestational zinc deficiency on genetically susceptible foetuses. The psychosis seen is suggested to be due to a combination of dietary or otherwise induced zinc deficiency and lack of zinc releasing capacity in the hippocampus. A non genetic but transmissable immune defect is suggested to be relevant to psychosis and to the nonmendelian pattern of inheritance of the disorder.

The side effects of antimalarial drugs indicates a polyamine involvement in both schizophrenia and depression

The nature of the side effects produced by the antimalarials and a common moiety present in these drugs (spermidine) links the polyamines to both schizophrenia and depression. The raised incidence of psychosis in systemic lupus erythematosus and during pregnancy both associated with raised blood polyamine levels, makes the involvement of the polyamines in psychosis more likely.

The Hawkins needle-guide system for percutaneous catheterization: 1. Instrumentation and procedure

In 1979, a new 22 gauge "skinny"-needle cannula system was introduced for combined percutaneous transhepatic cholangiography and drainage procedures. This small-bore system safely permits multiple passes when searching for small targets. Once the area of interest is entered, drainage can be accomplished with the same needle insertion by advancing either a 5 French straight Teflon or 6.5 French Teflon retention catheter over the stiff 22 gauge cannula. The distal tip of a catheter is looped using a continuous strand of monofilament, which helps to prevent catheter dislodgment. For 103 cholangiograms attempted, the overall success rate was 97%, including 95% in nondilated intrahepatic biliary tracts, with no major complications.

The Hawkins needle-guide system for percutaneous catheterization: 2. Clinical experience in biliary tract and abscess drainage

In 1979, a new, 22 gauge needle guide was introduced for combined percutaneous transhepatic cholangiography and biliary drainage procedures. In 103 biliary procedures and 29 abscess drainages using this needle guide, there were no major complications. The use of a small-volume (1-2 ml), low-pressure contrast injection followed by 24 hr of external decompression using self-retaining catheters (Cope loop, accordion) has reduced sepsis as a problem in biliary procedures. Small targets (1-2 cm abscess cavities) can be safely searched for with this 22 gauge needle guide. Two multiloculated abscesses were successfully drained by applying the surgical principle of ingress-egress irrigation catheters for infected cavities.

A Limited Comparison of the Mechanical Strength of Austenitic Steel in 1200 F Sodium, Air, and Helium

The mechanical properties of 316 stainless steel were measured at room temperature and at 1200 F during exposure to environments of air, helium and “clean” sodium. The test results were: Test: Cyclic strain / Environment: Air - Least cycles to failure; Environment: Helium - Most cycles to failure; Environment: Sodium - Between air and helium values. Test: Rupture / Environment: Air/Helium - No significant difference in rupture strenth; Environment: Sodium - Possible increase in ductility compared to air. Test: Creep / Environment: Air - Lowest rate; Environment: Helium - Highest rate; Environment: Sodium - Between air and helium values. Test: Tensile / Environment: Air/Helium/Sodium - 5 percent or less difference in tensile strength; 6 percent or less difference in yield strength. The small changes seen in the rupture, creep, and tensile tests, due to different environments, are considered insignificant when compared to overall variations between heats of stainless steel. The differences seen in cyclic strain tests reflect changes in material surface condition produced by environment.