A new diagnostic work-up for defining anemia etiologies: a cohort study in patients ≥ 50 years in general practices.

BACKGROUND: To study etiologies of anemia using an extensive laboratory analysis in general practices. METHOD: An extensive laboratory analysis was performed in blood of newly diagnosed anemia patients aged ≥50 years from the general population in the city of Dordrecht area, the Netherlands. Eight laboratory-orientated etiologies of anemia were defined. Patients were assigned one or more of these etiologies on the basis of their test results. RESULTS: Blood of 4152 patients (median age 75 years; 49% male) was analyzed. The anemia etiology was unclear in 20%; a single etiology was established in 59%; and multiple etiologies in 22% of the patients. The most common etiologies were anemia of chronic disease (ACD) (54.5%), iron deficiency anemia (IDA) (19.1%) and renal anemia (13.8%). The most common single etiologies were IDA (82%) and ACD (68%), while the multiple etiologies most commonly included folic acid deficiency (94%) and suspected bone marrow disease (88%). Older age was associated with a lower incidence of IDA and a higher incidence of renal anemia. Mild anemia was more often associated with ACD and uncertain anemia, while severe anemia was mainly seen in patients with IDA. CONCLUSION: Extensive laboratory analysis in anemic patients from the general population helped clarify the etiology of anemia and revealed many various combinations of etiologies in a significant proportion of patients. Age, sex and the severity of anemia are predictive of the underlying etiology.

Decision-making by the NICE Interventional Procedures Advisory Committee.

BACKGROUND: This study explored the evidence base for recommendations by the National Institute of Health and Care Excellence (NICE) Interventional Procedures Advisory Committee, the only NICE committee not to consider cost. The four potential recommendations are: Standard Arrangements (can be performed as routine practice in the NHS); Special Arrangements (can be done under certain conditions); Research Only; and Do Not Do. METHODS: Quantitative content analysis of data extracted from all published Interventional Procedure Guidance (IPG) for 2003-2018 (n = 496) was undertaken. All data were extracted independently by two researchers; disagreements were clarified by consensus. Data were tabulated, descriptive statistics produced, and regression analyses performed. RESULTS: The proportion of IPGs by recommendation was: 50·0 per cent Standard Arrangements; 37·2 per cent Special Arrangements; 11·1 per cent Research Only; and 1·6 per cent Do Not Do. There was a clear trend over time: the proportion of recommendations for Standard Arrangements decreased, whereas the evidence threshold increased. Adjusted mean numbers of patients in the evidence base by recommendation type were: Standard, 4867; Special, 709; Research Only, 386. Regression analyses confirmed that the year of recommendation, numbers of patients and levels of evidence all affected the likely recommendation. CONCLUSION: This study suggests that the likelihood of achieving the most positive recommendation (Standard Arrangements) is decreasing, and that this is most likely due to evidential requirements becoming more demanding. These findings are distinct from those reported for other NICE committees, for which the cost and statistical superiority of new therapies are among the drivers of recommendations.

ANTECEDENTES: Este estudio analiza los niveles de evidencia de las recomendaciones propuestas por el Interventional Procedures Advisory Committee del National Institute of Health and Care Excellence (NICE), el único comité NICE que no tiene en consideración los costes en la guía para los procedimientos de intervención. Las cuatro recomendaciones potenciales son: disposiciones estándar (se pueden efectuar sin restricciones en el marco del NHS); disposiciones especiales (se pueden efectuar bajo ciertas condiciones), en el ámbito de la investigación solo; y no intervenir. MÉTODOS: Se realizó un análisis cuantitativo del contenido de todas las Interventional Procedure Guidance (IPG) publicadas entre 2003-2018 (n = 496). Se obtuvieron todos los datos de forma independiente por dos investigadores y los desacuerdos entre ellos se decidieron por consenso. Se tabularon los datos y se realizaron estadísticas descriptivas y análisis de regresión. RESULTADOS: La proporción de las IPG según el tipo de recomendación eran estándar en el 50% de los casos, especial en el 37%, solo investigación en el 11% y no intervenir en el 2%. Se observó una clara tendencia a lo largo del tiempo: la proporción de recomendaciones del tipo de disposiciones estándar disminuía, mientras que el umbral para la evidencia aumentaba. La media ajustada del número de pacientes para cada tipo de recomendación (estándar, específica y solo investigación) fue de 4.867, 709 y 386, respectivamente. Los análisis de regresión confirmaron que el año de la recomendación, el número de pacientes y los niveles de evidencia afectaban el tipo de recomendación. Estos resultados son diferentes a los relativos a otros comités de NICE, en los que el coste y la superioridad estadística de las nuevas terapias son los motores de las recomendaciones. CONCLUSIÓN: Este estudio sugiere que la probabilidad de lograr la recomendación más positiva (disposición estándar) está disminuyendo, y ello con toda probabilidad es debido a que los requerimientos relacionados con la evidencia son cada vez más exigentes.

The impact of continuous haemofiltration with high-volume fluid exchange during cardiopulmonary bypass surgery on the recovery of patients with impaired renal function: a pilot randomised trial.

BACKGROUND: There is widespread variability in clinical practice within cardiac surgery units worldwide on the use of haemofiltration. The clinical impact and safety of this modality is, however, unknown. OBJECTIVES: The primary pilot trial objectives were as follows: to assess the feasibility of randomising 60 patients with impaired kidney function undergoing on-pump coronary artery bypass graft (CABG) surgery within 6 months; to assess the suitability and reliability of our chosen outcome measures; to explore issues that may impact on recruitment into a definitive trial; and to undertake an exploratory economic evaluation. DESIGN: A pilot, single-centre, open-label randomised trial. SETTING: Liverpool Heart and Chest Hospital NHS Foundation Trust between November 2010 and March 2012. PARTICIPANTS: Men and women, aged > 18 years of age, undergoing on-pump CABG surgery, who had pre-operative impaired kidney function indicated by an estimated glomerular filtration rate (eGFR) of < 60 ml/minute adjusted for 1.73 m(2) of body surface area. INTERVENTIONS: Group 1: patients who received haemofiltration during bypass (experimental group). Group 2: patients who did not receive haemofiltration during bypass (control group). MAIN OUTCOME MEASURES: (1) Feasibility outcome measures: barriers to recruitment to a larger trial were documented as observations made during the recruitment period of the trial. Reliability of data collection methods was monitored using a 13-point case record form validation check for data entry against the patient clinical notes and the trial database. (2) The main clinical outcomes were frequency of intensive care unit (ICU) stay of duration > 3 days and the length of ICU stay days. (3) Other clinical outcomes were the need for postoperative haemofiltration in the ICU, mechanical ventilation time, hospital stay, composite of outcome of unfavourable perioperative events and eGFR values at 6 weeks' follow-up. (4) Secondary health economic feasibility outcomes. RESULTS: Recruitment into the pilot trial was from 21 November 2010 to 30 March 2012. Thirty-seven eligible patients were consented and successfully randomised into the trial arms (30%). The main issues impacting on recruitment were the high volume of off-pump CABG surgery within the centre; recruitment being restricted to research nurses' working hours of the week; issues arising associated with the screening process for identifying prospective eligible patients based on eGFR values; protocol deviations/treatment crossovers; and unexpected outbreaks of pandemic influenza and other infectious conditions. The data collection process was sufficiently robust, with few errors detected. The length of ICU stay days was deemed a suitable primary outcome. There was an overall trend towards reduction in the length of ICU stay for patients who were given intraoperative haemofiltration, more so for those with diabetes. The economic evaluation estimated that the incremental costs per person were £1744 lower for the intraoperative haemofiltration group, while the incremental benefits per person increased by 0.11. CONCLUSION: Given sufficient resources and broadening of the inclusion criteria, the recruitment into a larger multicentre trial is feasible and may demonstrate potential clinical and cost benefits of using intraoperative haemofiltration in this group of patients. However, owing to the small sample size in this pilot trial, no firm conclusions can be drawn from the findings at this stage. The outcomes of this pilot study are very encouraging and suggest that it is feasible to design a continuous superiority trial with the length of ICU stay days or time to tracheal extubation as the primary outcome measure, provided that guidelines for avoiding bias are implemented. An alternative primary outcome measure that avoids bias is mortality. The inclusion criteria should also be widened to include all cardiac surgery patients with impaired renal function. TRIAL REGISTRATION: ISRCTN49513454. FUNDING: This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 17, No. 49. See the HTA programme website for further project information.

A pilot randomised controlled trial in intensive care patients comparing 7 days' treatment with empirical antibiotics with 2 days' treatment for hospital-acquired infection of unknown origin.

BACKGROUND: Management of cardiac intensive care unit (ICU) sepsis is complicated by the high incidence of systemic inflammatory response syndrome, which mimics sepsis but without an infective cause. This pilot randomised trial investigated whether or not, in the ICU, 48 hours of broad-spectrum antibiotic treatment was adequate to safely treat suspected sepsis of unknown and unproven origin and also the predictive power of newer biomarkers of sepsis. OBJECTIVE: The main objective of this pilot study was to provide preliminary data on the likely safety and efficacy of a reduced course of antibiotics for the treatment of ICU infections of unknown origin. DESIGN: A pilot, single-centre, open-label randomised trial. SETTING: This study was carried out in the ICU of a tertiary heart and chest hospital. PARTICIPANTS: Patients being treated within the ICU were recruited into the trial if the intensivist was planning to commence antibiotics because of evidence of systemic inflammatory response syndrome and a strong suspicion of infection but there was no actual known source for that infection. INTERVENTIONS: Broad-spectrum antibiotic treatment administered for 48 hours (experimental) compared with treatment for 7 days (control). MAIN OUTCOME MEASURES: The primary outcome was a composite outcome of the rate of death or initiation of antibiotic therapy after the completion of the treatment schedule allocated at randomisation. Secondary outcomes included the duration of mechanical ventilation and ICU and hospital stay; the incidence of infection with Clostridium difficile (B. S. Weeks & E. Alcamo) Jones & Bartlett International Publishers, 2008, or methicillin-resistant Staphylococcus aureus (MRSA) (B. S. Weeks & E. Alcamo) Jones & Bartlett International Publishers, 2008; resource utilisation and costs associated with each of the two pilot arms; the ratio of patients screened to patients eligible to patients randomised; the incidence of crossover between groups; and the significance of newer biomarkers for sepsis for predicting patients' need for further antibiotics. RESULTS: A total of 46 patients were recruited into the trial, with 23 randomised to each group. There was no significant difference between the two groups in terms of the composite primary outcome measure. The risk difference was 0.12 [95% confidence interval (CI) 0.11 to 0.13; p = 0.3]. In the 2-day group, four patients (17.4%) required further antibiotics compared with three (13%) in the 7-day group. Four patients died within the trial period and the deaths were not trial related. Patients who died during the trial period received no additional antibiotics in excess of their trial allocation. There were no documented incidences of MRSA or C. difficile infection in either group. No significant differences in adverse events were observed between the groups. Key economic findings were mean antibiotic costs per patient of £168.97 for the 2-day group and £375.86 for the 7-day group. The potential per annum cost saving for the ICU of 2-day treatment was estimated to range from £108,140 to £126,060. Patient screening was considered the biggest barrier to recruitment. There was no crossover between the two randomised groups. Data verification ascertained > 98% accuracy in data collection. Baseline procalcitonin was found to be predictive of the composite outcome (death and needing further antibiotics) (odds ratio 1.79, 95% CI 1.20 to 2.67; p = 0.005). Analysis of baseline procalcitonin also indicated a trend towards it being a predictor of restarting antibiotics, with an odds ratio of 1.45 (95% CI 1.04 to 2.02; p = 0.01). CONCLUSIONS: Data from this pilot study suggest that there could be significant benefits of reducing broad-spectrum antibiotic use in the ICU without it undermining patient safety, with a potential cost saving in our unit of over £100,000 per year. Evidence from this pilot trial is not definitive but warrants further investigation using a large randomised controlled trial. TRIAL REGISTRATION: Current Controlled Trials ISRCTN82694288. FUNDING: This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 16, No. 36. See the HTA programme website for further project information.

[Tick-borne disease or not? Do not let yourself be fooled]. / Tekenbeetziekte ofniet? Laat u niet beetnemen.

Confusion among physicians and patients is increasing regarding the diagnosis and treatment ofLyme borreliosis due to the enormous amount ofambiguous information available and media attention. Some of the dilemmas that physicians encounter are illustrated by 3 patients with a range of symptoms, one of whom was convinced she had Lyme borreliosis. However none of these patients had significant evidence that suggested Lyme borreliosis. Physicians should follow the guidelines developed by the Dutch Institute for Health Care Improvement (CBO) or the Infectious Diseases Society of America rather than 'alternative' guidelines, which are not evidence-based.

Refinement of the chromosome 16 locus for benign familial infantile convulsions.

Benign familial infantile convulsions (BFIC) is an autosomal dominantly inherited partial epilepsy syndrome of early childhood with remission before the age of 3 years. The syndrome has been linked to loci on chromosomes 1q23, 2q24, 16p12-q12, and 19q in various families. The aim of this study was to identify the responsible locus in four unrelated Dutch families with BFIC. Two of the tested families had pure BFIC; in one family, affected individuals had BFIC followed by paroxysmal kinesigenic dyskinesias at later age, and in one family, BFIC was accompanied by later-onset focal epilepsy in older generations. Linkage analysis was performed for the known loci on chromosomes 1q23, 2q24, 16p12-q12, and 19q. The two families with pure BFIC were linked to chromosome 16p12-q12. Using recombinants from these and other published families, the chromosome 16-candidate gene region was reduced from 21.4 Mb (4.3 cm) to 2.7 Mb (0.0 cm). For the other two families, linkage to any of the known loci was unlikely. In conclusion, we confirm the linkage of pure BFIC to chromosome 16p12-q12, with further refinement of the locus. Furthermore, the lack of involvement of the known loci in two of the families indicates further genetic heterogeneity for BFIC.

[Back pain? Don't forget the abdomen]. / Pijn in de rug? Vergeet de buik niet.

Three patients, men aged 62, 57 and 44 years, had suffered for 6-24 months from low back pain, which after an acute moment had worsened with pain radiating to one leg. In all 3 patients, a neurological cause was considered first, but investigations revealed that they had a large abdominal aortic aneurysm (AAA) resulting in emergency surgery. The oldest man died from late complications; the younger men made a good recovery. An AAA should be considered in patients with low back pain and risk factors such as male gender, older age, cigarette smoking, hypertension and previous manifestations of vascular disease. Making the diagnosis as early as possible can be lifesaving.

[Two children seriously weakened by myasthenia]. / Twee ernstig verzwakte kinderen door myasthenie.

Two boys, aged 2 and 11 years, presented with fever and muscle weakness that resulted in respiratory insufficiency. A physical examination and additional tests confirmed the diagnosis 'myasthenia'. Acetyl cholinesterase-inhibitor therapy had a favourable effect. Myasthenia is a diagnosis that should be considered for every child presenting with muscle weakness of unknown origin.

Membrane-aerated biofilm reactor for the removal of 1,2-dichloroethane by Pseudomonas sp. strain DCA1.

A membrane-aerated biofilm reactor (MBR) with a biofilm of Pseudomonas sp. strain DCA1 was studied for the removal of 1,2-dichloroethane (DCA) from water. A hydrophobic membrane was used to create a barrier between the liquid and the gas phase. Inoculation of the MBR with cells of strain DCA1 grown in a continuous culture resulted in the formation of a stable and active DCA-degrading biofilm on the membrane. The maximum removal rate of the MBR was reached at a DCA concentration of approximately 80 micro M. Simulation of the DCA fluxes into the biofilm showed that the MBR performance at lower concentrations was limited by the DCA diffusion rate rather than by kinetic constraints of strain DCA1. Aerobic biodegradation of DCA present in anoxic water could be achieved by supplying oxygen solely from the gas phase to the biofilm grown on the liquid side of the membrane. As a result, direct aeration of the water, which leads to undesired coagulation of iron oxides, could be avoided.

A comparison of the recognition distance of several types of pedestrial signals with low-vision pedestrians.

Although approximately 80-85% of the legally blind population has some residual vision, little research has examined the relative conspicuity of various types of visual pedestrian signals currently used by cities with this group of pedestrians. This research compared the relative conspicuity of an incandescent WALK sign, a white LED WALK sign, a blue LED WALK sign, and white and blue LED WALK signs that included an animated "eyes" display with legally blind participants who had some vision. All WALK signals were equated for brightness with the use of a N.I.S.T.-certified illuminance meter. Participants had to discriminate whether the test stimulus was a blue/white WALK sign or a blue/white DON'T WALK sign. Test stimuli were presented in randomized blocks of trials, and recognition distances were determined by having participants approach the test stimuli until they could identify them. Results indicated that there were no significant differences between the incandescent and LED signals without the animated eyes or between the blue and white LED signals. However, Tukey's method showed a significant contrast between the signals with the animated eyes display and signals without this display (F=149.88, P value<0.0001). Participants could identify the Walk signal 62% further away when it also contained the animated "eyes" display. These results show that the addition of an animated "eyes" display to the WALK sign significantly improves recognition distance for a large segment of persons with visual impairment.

Increasing motorist compliance and caution at stop signs.

This study evaluated strategies to improve motorist compliance and caution at three stop-sign-controlled intersections with a history of motor vehicle crashes. The primary intervention was a light-emitting diode (LED) sign that featured animated eyes scanning left and right to prompt drivers to look left and right for approaching traffic. Data were scored from videotape on the percentage of drivers coming to a complete stop and the percentage of drivers looking right before entering the intersection. Observational data were collected on the percentage of right-angle conflicts (defined as braking suddenly or swerving from the path to avoid an intersection crash). The introduction of the LED sign according to a multiple baseline across the three intersections was associated with an increase in the percentage of vehicles coming to a complete stop at all three intersections and a small increase in the percentage of drivers looking right before entering the intersections. Conflicts between vehicles on the major and minor road were also reduced following the introduction of the animated eyes prompt.

Thermophilic sulphate and sulphite reduction in lab-scale gas-lift reactors using H(2) and CO(2) as energy and carbon source.

Feasibility of thermophilic (55 degrees C) sulphate and sulphite reduction with H(2) and CO(2) gas-mixtures was studied in gas-lift reactors, which contained pumice particles as carrier material. Particular attention was paid to biomass retention and the competition between hydrogenotrophic sulphate-reducers and other hydrogenotrophic thermophiles. A model medium with defined mineral nutrients was used.The results of the experiments clearly demonstrate that sulphate conversion rates up to 7.5 g SO(4) (2-)/L per day can be achieved. With sulphite, a reduction rate of 3.7 g S/L per day was obtained, which equals a sulphate conversion rate of 11.1 g SO(4) (2-)/L per day. Under the applied conditions, a strong competition for hydrogen between hydrogenotrophic sulphate-reducers, tentatively designated as Desulfotomaculum sp., and hydrogenotrophic methanogens was observed. The outcome of the competition could not be predicted. Growth of the mixed culture was totally inhibited at an H(2)S concentration of 250 mg/L. Poor attachment of sulphate-reducing bacteria was observed in all experiments. The biomass concentration did not exceed 1.2 g/L, despite the presence of 50 g/L of pumice. The reason for this phenomenon remains to be understood. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55: 807-814, 1997.

[Prader-Willi syndrome in a young infant]. / Het Prader-Willi-syndroom bij de jonge zuigeling.

Four children aged 2.5 years, 15.7 and 7 months, including a pair of twins, after birth displayed hypotonia which necessitated tube feeding. Other features were a narrow forehead and a thin triangular upper lip, but these abnormalities were not conspicuous. An extensive supplementary examination for cerebral and muscular disorders initially failed to produce a diagnosis. It was only when the Prader-Willi syndrome was suspected and a corresponding abnormality on chromosome 15 was looked for that this diagnosis could be made. Early diagnosis of this syndrome will avoid further invasive diagnostic procedures and make early treatment possible.

The use of feedback signs to increase observed daytime seat belt use in two cities in North Carolina.

Well publicized enforcement programs in North Carolina have raised seat belt use to about 80%. In an effort to find techniques to raise belt use further, signs providing feedback to drivers on belt use rates were introduced in two communities, Asheboro (population 18,000) and Greensboro (population 183,000). Feedback signs remind motorists about belt use and imply a constant and vigorous enforcement presence. The signs were prominently posted by the roadside at high volume locations; belt use information was changed weekly based on observational surveys. Observed daytime driver belt use in Asheboro increased from an average of 75% before the signs to 89% after the signs were established. At urban sites in Greensboro, driver belt use increased from 80% to 86%. Right front passenger belt use increased significantly in Asheboro but not in Greensboro. There were no changes in belt use at two interstate exit sites in Greensboro. Reasons for the differential success rates may relate to differences in initial belt use rates, community size, amount of publicity, and numbers of encounters with the signs. It is clear, however, that feedback signs can be an important supplement to belt use enforcement programs.

A comparison of the characteristics of self-stimulatory behaviors in "normal" children and children with developmental delays.

We examined the occurrence and characteristics of self-stimulatory behaviors in 10 nonhandicapped children and 5 children with developmental delays. Each child with a developmental delay was matched with two normal comparison children, one for chronological age and the other for mental age. The subjects were videotaped in four everyday settings. It was found that few differences existed between the children with developmental delays and their age-matched pairs in the percentage of time they engaged in self-stimulatory behavior, the variety of self-stimulatory behavior, how fast or slowly a behavior was preformed, or the degree of perseveration of each of the behaviors. However, the children with developmental delays and their mental age matches displayed higher levels of obvious and gross motor behavior than the chronological age matches, and the children with developmental delays were more likely to be visually oriented towards their behavior than their age-matched pairs. A measure of judged bizarreness of various self-stimulatory behaviors indicated that obvious gross motor behaviors received the highest bizarreness ratings.

Biological sulfate reduction using synthesis gas as energy and carbon source.

Biological sulfate reduction was studied in laboratory-scale gas-lift reactors. Synthesis gas (gas mixtures of H(2)/CO/CO(2)) was used as energy and carbon source. The required biomass retention was obtained by aggregation and immobilization on pumice particles. Special attention was paid to the effect of CO addition on the sulfate conversion rate, aggregation, and aggregate composition.Addition of 5% CO negatively affected the overall sulfate conversion rate; i.e., it dropped from 12-14 to 6-8 g SO(2-) (4)/L day. However, a further increase of CO to 10 and 20% did not further deteriorate the process. With external biomass recycling the sulfate conversion rate could be improved to 10 g SO(2-) (4)/L day. Therefore biomass retention clearly could be regarded as the rate-limiting step. Furthermore, CO affected the aggregate shape and diameter. Scanning electron microscopy (SEM) photographs showed that rough aggregates pregrown on H(2)/CO(2) changed into smooth aggregates upon addition of CO. Addition of CO also changed the aggregate Sauter mean diameter (d(32)) from 1.7 mm at 5% CO to 2.1 mm at 20% CO. After addition of CO, a layered biomass structure developed. Acetobacterium sp. were mainly located at the outside of the aggregates, whereas Desulfovibrio sp. were located inside the aggregates.

Topical active H1-antihistamines and their effect on nasal airway resistance.

The introduction of a topically active H1-antihistamine nasal spray Azelastine, has given an extra dimension in the management of allergic rhinitis. The drug acts rapidly and avoids the systemic adverse effects of antihistimines. An objective prospective study was performed to detect the effect of Azelastine nasal spray on nasal airway resistance. Twelve healthy adult volunteers with no rhinological problems were included in the study. Nasal cavities were sprayed with 280 micrograms (two puffs) of Azelastine nasal spray and the nasal airway resistance was measured with anterior rhinomanometry at intervals of 30 minutes for up to two hours. Our study has shown a statistically significant increase in the total nasal airway resistance following the use of Azelastine nasal spray in the absence of a subjective change in nasal airway resistance. There are substances when inhaled which can cause subjective improvement in nasal airway patency without changing the measured nasal airway resistance. However this medication gives no subjective change in nasal airway patency in spite of increasing nasal airway resistance.

The effects of low alcohol beverages on alcohol consumption and impairment.

We examined the effects of providing drinks with half the alcohol level on alcohol consumption and blood alcohol concentration (BAC) of 4 patrons of a private club. Alcohol consumption was measured by observers and level of impairment was determined from breath samples obtained by digitalized ALERT (Alcohol Level Evaluation Road Tester) breath testing devices. An alternating treatments design was employed to compare the sessions during which people drank mixed drinks with their usual alcohol concentration with sessions during which they drank mixed drinks with half the alcohol concentration that cost half as much as the regular drinks. All 4 participants consumed less alcohol during sessions when they received drinks with the lower alcohol content. BAC was also less on all but two sessions during the low alcohol condition.

Biological sulphate reduction using gas-lift reactors fed with hydrogen and carbon dioxide as energy and carbon source.

Feasibility and engineering aspects of biological sulphate reduction in gas-lift reactors were studied. Hydrogen and carbon dioxide were used as energy and carbon source. Attention was paid to biofilm formation, sulphide toxicity, sulphate conversion rate optimization, and gas-liquid mass transfer limitations. Sulphate-reducing bacteria formed stable biofilms on pumice particles. Biofilm formation was not observed when basalt particles were used. However, use of basalt particles led to the formation of granules of sulphate-reducing biomass. The sulphate-reducing bacteria, grown on pumice, easily adapted to free H(2)S concentrations up to 450 mg/L. Biofilm growth rate then equilibrated biomass loss rate. These high free H(2)S concentrations caused reversible inhibition rather than acute toxicity. When free H(2)S concentrations were kept below 450 mg/L, a maximum sulphate conversion rate of 30 g SO(4) (2-)/L x d could be achieved after only 10 days of operation. Gas-to-liquid hydrogen mass transfer capacity of the reactor determined the maximum sulphate conversion rate.

Late effects of locally delivered mitomycin C on formation of neointima and on vasomotor response to acetylcholine.

BACKGROUND: Balloon angioplasty damages endothelial cells and stimulates smooth muscle cell proliferation. The effects of local cytotoxic drug therapy on formation of neointima and late endothelial function are not known. This study was designed to determine whether direct infusion of mitomycin C via a microporous balloon catheter could significantly reduce formation of neointima after angioplasty. Furthermore, we investigated whether endothelial cell function is normal 7 weeks after the initial microporous angioplasty procedure. METHODS: In 34 New Zealand white rabbits, bilateral external iliac arteries underwent balloon angioplasty, followed by either high-dose (0.66 mg/kg) or low-dose (0.025 mg/kg) mitomycin C in one iliac artery and saline infusion in the contralateral artery, and a control group was given saline in both vessels. Formation of neointima was measured in the iliac arteries after 7 weeks by morphometry. Before sacrifice of 17 'angioplasty' rabbits and three undamaged rabbits, graded doses of acetylcholine and isosorbide dinitrate were infused in the distal aorta, and the iliac artery diameter was measured by computerized quantitative angiography. RESULTS: No significant differences in the absolute area of the intima or the intima: media ratio were demonstrated between control arteries and arteries that were directly infused with either high-dose or low-dose mitomycin. However, within the high-dose group, the mitomycin-treated vessel had a significantly lesser extent of formation of intimal hyperplasia (0.17 +/- 0.03 versus 0.27 +/- 0.03 mm2, P < 0.03) and lower intima: media area ratio (0.60 +/- 0.31 versus 1.09 +/- 0.42, P < 0.03) than the contralateral saline-treated vessel. Significant increases in mean luminal iliac artery diameter [0.18 mm (10.5%) at 1 min and 0.23 mm (13%) at 3 min, P < 0.05)] from baseline values following acetylcholine were observed in previously damaged iliac arteries. This vasodilatory response was not different from that in undamaged arteries. CONCLUSIONS: Local delivery of mitomycin C had no favorable effect on the inhibition of intimal hyperplasia compared with control saline-treated arteries. Normal endothelial function, determined on the basis of dilatory response to acetylcholine, can be demonstrated 7 weeks after balloon angioplasty injury.