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Biomedical subjects

J Vale

Publications and source records attributed to J Vale.

At least 19 recordsLinked to original sources
PubMed2006

Use of zeolitised coal fly ash for landfill leachate treatment: a pilot plant study.

Treatment of municipal solid waste (MSW) landfill leachate generally results in low percentages of nutrient removal due to the high concentration and accumulation of refractory compounds. For this reason, individual physical, chemical and biological processes have been used for the treatment of raw landfill leachate and sometimes for the mixture of domestic wastewater and landfill leachate. In this work, the possibility of treating landfill leachate was tested in a bench-scale pilot plant by a two-step method combining adsorption and coagulation-flocculation. Zeolite synthesized from coal fly ash, a by-product of coal-fired power stations, was used in this study both as a decantation aid reagent and as an adsorbent of COD and NH4-N. The coagulation-flocculation step was performed by the use of aluminium sulphate and a polyelectrolyte (ACTIPOL A-401). The leachate was collected directly from a storage unit of the organic fraction of MSW, before it was composted. For this reason the raw leachate was diluted before treatment. The sludge was recirculated to enhance the removal efficiency of nutrients as well as to optimize flocculant saving and to decrease sludge production. The results showed that it is possible to remove 43%, 53% and 82% of COD, NH4-N, and suspended solids, respectively. Therefore, this method may be an alternative for ammonium removal, as well as a suitable pre- or post-treatment step, in combination with other processes in order to meet regulatory limits.

Alum Compounds↗
PubMed2004

Robot-assisted laparoscopic adrenalectomy: preliminary UK results.

OBJECTIVE: To describe the results of our first two cases of laparoscopic adrenalectomy using the da Vinci surgical system (Intuitive Surgical, Inc., Mountain View, CA, USA). PATIENTS AND METHODS: Amongst 75 robot-assisted procedures performed at our institution, two patients underwent robot-assisted laparoscopic adrenalectomy. The set-up time, procedure time, hospital stay, complications and outcomes were recorded. RESULTS: Both operations were completed successfully using the robot; the mean (range) set-up time was 31 (25-37) min and mean procedure time 118.5 (107-130) min. One patient had a postoperative pulmonary embolus and was discharged 5 days after surgery; the second patient was discharged after 3 days. There were no intraoperative complications; both patients were well at the 1-year follow-up. CONCLUSIONS: Robot-assisted laparoscopic adrenalectomy is technically feasible and can be conducted efficiently and safely with the da Vinci surgical system.

Adenoma↗
PubMed2002

Trinucleotide repeats in 202 families with ataxia: a small expanded (CAG)n allele at the SCA17 locus.

BACKGROUND: Ten neurodegenerative disorders characterized by spinocerebellar ataxia (SCA) are known to be caused by trinucleotide repeat (TNR) expansions. However, in some instances the molecular diagnosis is considered indeterminate because of the overlap between normal and affected allele ranges. In addition, the mechanism that generates expanded alleles is not completely understood. OBJECTIVE: To examine the clinical and molecular characteristics of a large group of Portuguese and Brazilian families with ataxia to improve knowledge of the molecular diagnosis of SCA. PATIENTS AND METHODS: We have (1) assessed repeat sizes at all known TNR loci implicated in SCA; (2) determined frequency distributions of normal alleles and expansions; and (3) looked at genotype-phenotype correlations in 202 unrelated Portuguese and Brazilian patients with SCA. Molecular analysis of TNR expansions was performed using polymerase chain reaction amplification. RESULTS: Patients from 110 unrelated families with SCA showed TNR expansions at 1 of the loci studied. Dominantly transmitted cases had (CAG)(n) expansions at the Machado-Joseph disease gene (MJD1) (63%), at SCA2 (3%), the gene for dentatorubropallidoluysian atrophy (DRPLA) (2%), SCA6 (1%), or SCA7 (1%) loci, or (CTG)(n) expansions at the SCA8 (2%) gene, whereas (GAA)(n) expansions in the Freidreich ataxia gene (FRDA) were found in 64% of families with recessive ataxia. Isolated patients also had TNR expansions at the MJD1 (6%), SCA8 (6%), or FRDA (8%) genes; in addition, an expanded allele at the TATA-binding protein gene (TBP), with 43 CAGs, was present in a patient with ataxia and mental deterioration. Associations between frequencies of SCA2 and SCA6 and a frequency of large normal alleles were found in Portuguese and Brazilian individuals, respectively. Interestingly, no association between the frequencies of DRPLA and large normal alleles was found in the Portuguese group. CONCLUSIONS: Our results show that (1) a significant number of isolated cases of ataxia are due to TNR expansions; (2) expanded DRPLA alleles in Portuguese families may have evolved from an ancestral haplotype; and (3) small (CAG)(n) expansions at the TBP gene may cause SCA17.

Adenine↗
PubMed2002

Idiopathic localised bladder amyloidosis: rare cause of haematuria.

Idiopathic Localised Bladder Amyloidosis is a rare cause of haematuria and urinary tract symptoms. A review of the literature highlights the varied presentations and the appropriate investigations for this condition, with emphasise on the exclusion of a secondary cause. In addition, the range of treatment options is fully discussed. Our report on a 65-year old gentleman illustrates that a high index of suspicion is required for its diagnosis. Furthermore, conservative management can be an effective strategy in selected patients.

Aged↗
PubMed2002

Progressive myoclonic ataxia and JC virus encephalitis in an AIDS patient.

A case of progressive myoclonic ataxia in an AIDS patient is described, which evolved over a 13 month period. The ataxia persisted as the only clinical finding for several months before the appearance of a severe tetraparesis and cachexia. Throughout the clinical progression, magnetic resonance imaging (MRI) revealed the presence of bilateral, progressive, isolated, and symmetrical lesions involving the red nuclei, subthalami, thalami, lenticular nuclei, and primary motor cortices. Neuropathological examination, supplemented by in situ hybridisation for JC virus DNA, confirmed that the lesions were those of progressive multifocal leucoencephalopathy (PML). The exceptional clinical presentation of PML in this case is the first report of progressive myoclonic ataxia caused by PML. The selective nature of the lesions confirms the role of the dentato-rubral-thalamo-cortical tract in the pathogenesis of progressive myoclonic ataxia. The atypical MRI findings further emphasise the need for expanded diagnostic criteria for PML in AIDS patients and support the use of more aggressive diagnostic methods as new treatments become available.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Solidification/stabilization of electric arc furnace dust using coal fly ash. Analysis of the stabilization process.

In this paper, the stabilization of electric arc furnace (EAF) dust containing hazardous metals such as Pb, Cd, Cr or Zn is described. The treatment involves a waste solidification/stabilization (S/S) process, using coal fly ash as the fundamental raw material and main binder. The article also contains a brief review of the most important recent publications related to the use of fly ash as S/S agents. The efficacy of the process has been evaluated mainly through leaching tests on the solidified products and compliance with some imposed leachate limits. The concentration of metals leaching from the S/S products was strongly leachate pH dependent; thus, the final pH of the leachate is the most important variable in reaching the limits and, therefore, in meeting the stabilization goals. In this study, the dependence relationship between the leachate pH and the concentrations of metals in the leachate are analyzed; in some cases, this allows us to estimate the speciation of contaminants in the S/S solids and to understand the mechanism responsible for reduced leachability of heavy metals from solidified wastes.

Coal↗
PubMed2000

Erectile dysfunction following radical therapy for prostate cancer.

With the earlier detection of prostate cancer and the increasing demand for treatment of organ-confined dizease, quality of life issues are becoming more important. Development of erectile dysfunction (ED) following radical therapy is a particular concern, and occurs in perhaps a third of patients treated by radiotherapy and 30-70% of patients treated by radical prostatectomy. Although it is assumed that the ED relates to damage to the nerves subserving erection, this view has been questioned recently and in at least a proportion of patients the cause appears to be vascular. Despite the likely cause of their ED, all patients presenting with ED after treatment for prostate cancer should undergo assessment by history and examination to ensure that there are no other correctable risk factors. Patients can then be considered for a number of treatment options, and currently sildenafil (Viagra, Pfizer) is usually used as first-line therapy assuming there are no contraindications, such as severe ischaemic heart disease or nitrate therapy. Sildenafil improves erectile function in 70% of patients with ED post-radiotherapy, but appears less effective in men after radical prostate surgery with a response rate of 40-50%. Other treatment options include self-injection or intra-urethral administration of alprostadil, and some patients are happy to use a vacuum erection device. Finally, if all else fails, patients may be suitable for penile implant surgery.

Erectile Dysfunction↗
PubMed2000

Symptomatic paroxysmal hemidystonia due to a demyelinating subthalamic lesion.

We present a case of paroxysmal hemidystonia in a patient with an isolated demyelinating lesion in the subthalamic region, involving the posterior arm of the internal capsule and extending to the subthalamic nucleus and mesencephalon, possibly due to multiple sclerosis. Compared with similar reports in the literature, in our case there was a paucity of lesions, permitting a more direct clinico-anatomical correlation. The role of the subthalamic region and basal ganglia circuitry in the genesis of symptomatic dystonia is discussed.

Adult↗
PubMed2000

Benign prostatic hyperplasia and erectile dysfunction--is there a link?

There is little evidence to support a link between benign prostatic hyperplasia (BPH) and erectile dysfunction (ED). Any apparent relationship may reflect the fact that both are common conditions with a similar gender and age distribution. However, the surgical treatment of BPH (e.g. TURP or open prostatectomy) may cause ED as a postoperative complication in some patients. Similarly, the medical treatment of BPH with finasteride may be associated with ED (< 5% in one study). However, alpha-blockade is not associated with this side-effect.

Adrenergic alpha-Antagonists↗
PubMed2000

Microcirculatory studies in erectile disorders.

Local microcirculatory disturbances and fibrosis are thought to contribute to the pathogenesis of erectile dysfunction (ED). The assessment of these disturbances is now possible using non-invasive techniques such as laser Doppler flowmetry (LDF) and measuring transcutaneous pO2 and pCO2. However, these techniques need standardisation (e.g. in terms of equipment, conditions in which the examination is carried out and duration of measurement). Nevertheless, these techniques have a qualitative value. Marked alterations are seen in smokers and hypertensive patients. LDF has also been used to monitor the effect of treatment (e.g. after intracavernosal PGE1). These techniques remain non-diagnostic in individual patients. However, in groups of patients they may produce useful information (e.g. to assess treatments for ED).

Blood Gas Monitoring, Transcutaneous↗
PubMed1998

Inhibitors of glutathione reductase as potential antimalarial drugs. Kinetic cooperativity and effect of dimethyl sulphoxide on inhibition kinetics.

We have developed inhibitors of glutathione reductase that improve on the inhibition of literature lead compounds by up to three orders of magnitude. Thus, analogues of Safranine O and menadione were found to be strong, reversible inhibitors of yeast glutathione reductase. Safranine O exhibited partial, uncompetitive inhibition with Ki and alpha values of 0.5 mM and 0.15, respectively. Thionine O was a partial (hyperbolic) uncompetitive inhibitor with Ki and alpha values of 0.4 microM and 0.15, respectively. LY83583 and 2-anilino-1,4-naphthoquinone also showed (hyperbolic) partial, uncompetitive inhibition with micromolar Ki values. For Nile Blue A a model for two-site binding with (parabolic) uncompetitive inhibition fitted the data with a Ki value of 11 microM and a kinetic cooperativity between the sites of 0.12, increased to 0.46 by preincubation of the enzyme and Nile Blue A in the presence of glutathione disulphide. Analysis of the effects of preincubation on the kinetics and cooperativity indicated the possibility of a slow conformational change in the homodimeric enzyme, the first such indication of kinetic cooperativity in the native enzyme to our knowledge. Further evidence of conformational changes for this enzyme came from studies of the effects of dimethyl sulphoxide which indicated that this co-solvent, which at low concentrations has no apparent effect on initial velocities under normal assay conditions, induced a slow conformational change in the enzyme. Thionine O, Nile Blue A and LY83583 were redox-cycling substrates producing superoxide ion, detectable by means of cytochrome c reduction, but leading to no loss of glutathione reductase activity, under aerobic or anaerobic conditions. The water-soluble Safranine analogues Methylene Blue, Methylene Green, Nile Blue A and Thionine O (5 mg/kg i.p. x 5) were effective antimalarial agents in vivo against P. berghei, but their effect was small and a higher dose (50 mg/kg i.p. x 1) was toxic in mice. Comparison was made with human glutathione reductase and its literature-reported interactions with several tricyclic inhibitors as studied by X-ray diffraction. It is possible that the conformational changes detected in the present study from alterations in detailed kinetic inhibition mechanisms may shed light on information transfer through the glutathione reductase molecule from the dimer interface ligand pocket to the active-site.

Animals↗