Evaluation of models predicting insignificant prostate cancer to select men for active surveillance of prostate cancer.

BACKGROUND: In an era of personalized medicine, individualized risk assessment using easily available tools on the internet and the literature are appealing. However, uninformed use by clinicians and the public raises potential problems. Herein, we assess the performance of published models to predict insignificant prostate cancer (PCa), using a multi-national low-risk population that may be considered for active surveillance (AS) based on contemporary practice. METHODS: Data on men suitable for AS but undergoing upfront radical prostatectomy were pooled from three international academic institutions in Cambridge (UK), Toronto (Canada) and Melbourne (Australia). Four predictive models identified from literature review were assessed for their ability to predict the presence of four definitions of insignificant PCa. Evaluation was performed using area under the curve (AUC) of receiver operating characteristic curves and Brier scores for discrimination, calibration curves and decision curve analysis. RESULTS: A cohort of 460 men meeting the inclusion criteria of all four nomograms was identified. The highest AUCs calculated for any of the four models ranged from 0.618 to 0.664, suggesting weak positive discrimination at best. Models had best discriminative ability for a definition of insignificant disease characterized by organ-confined Gleason score ⩽6 with a total volume ⩽0.5 ml or 1.3 ml. Calibration plots showed moderate range of predictive ability for the Kattan model though this model did not perform well at decision curve analysis. CONCLUSIONS: External assessment of models predicting insignificant PCa showed moderate performance at best. Uninformed interpretation may cause undue anxiety or false reassurance and they should be used with caution.

Plasmacytoma of the atlas presenting as hoarseness: a rare cause of unilateral vocal fold palsy.

INTRODUCTION: Solitary bone plasmacytoma is a rare haematological malignancy that can present in a variety of ways. This study aimed to present a case of plasmacytoma of the atlas, as a rare cause of unilateral vocal fold palsy. METHOD: Case report. RESULTS: Following diagnosis via imaging and direct biopsy through the posterior pharyngeal wall, the patient was referred to the haematologists for further treatment of his plasmacytoma. CONCLUSION: Solitary bony plasmacytoma of the cervical spine is a rare haematological malignancy. Its presentation with a unilateral vocal fold palsy has not been previously described.

First report of Parabacteroides goldsteinii bacteraemia in a patient with complicated intra-abdominal infection.

Using 16S rRNA sequence analysis, we report the first isolation of Parabacteroides goldsteinii as a monobacterial isolate from blood culture in a patient with abdominal sepsis. P. goldsteinii phenotypically resembles Parabacteroides merdae and Parabacteroides distasonis and may be misidentified by commonly used enzymatic systems, suggesting that it may be more frequently present in clinical specimens than previously appreciated but either misidentified or ignored.

Oxidation of cyanide in aqueous solution by chemical and photochemical process.

Cyanide waste is found predominantly in industrial effluents generated from metallurgical operations. The toxicity of cyanide creates serious environmental problems. In this paper, oxidation of cyanide in aqueous solution was investigated using chemical and photochemical process. Chemical oxidation was studied at room temperature using H2O2 as oxidant and Cu2+ as catalyst. Photochemical oxidation was studied in an annular type batch photoreactor of 1l capacity using 25 W low-pressure (81.7% transmission at 254 nm wavelength) ultraviolet (UV) lamp along with H2O2 as oxidant. The effect of Cu2+ catalysis was also studied. It was observed that in absence of UV source, the degradation of cyanide by H2O2 alone was very slow, whereas copper ions accelerated the rate of reaction thereby acting as catalyst. Copper formed a complex with cyanide ion, i.e. tetracyanocuprate which had greater affinity for H2O2. Cyanate hydrolysis was also favoured by copper ions. As Cu2+ ion concentration was increased, rate of degradation also increased. Photochemical oxidation by H2O2 and Cu2+ was found to be the best system for cyanide degradation. CN- (100 mg/l) was degraded to non-detectable level in 9 min at pH 10.0 with optimum H2O2 dose of 35.5 mM and Cu2+ dose of 19 mg/l. Reaction kinetics of cyanide oxidation was found to be pseudo-first order and the rate constant has been determined for different processes.

Studies on photo-degradation of 2,4-dinitro toluene in aqueous phase.

The efficiency of different photo-degradation processes was evaluated for degrading 2,4-dinitro toluene (DNT) in aqueous phase. The rate and extent of DNT degradation and removal of total organic carbon (TOC) and total nitrogen (TN) contents were compared for direct photolytic and photo-oxidative reactions using various concentrations of H2O2 and Fenton's reagent with a 125 W medium pressure UV lamp. DNT was degraded rapidly under photo-oxidative conditions. Complete destruction was obtained using Fenton's reagent, wherein 100 ppm of DNT was degraded within 60 min of irradiation time. Removal of TOC and TN contents in the photo-Fenton system was 96% and 57%, respectively, after 2 h of UV irradiation. Degradation of DNT followed first order reaction kinetics. Photo-Fenton oxidation is found to be the most suitable technique to degrade DNT in aqueous phase.

Development of adsorptive removal process for treatment of explosives contaminated wastewater using activated carbon.

The adsorption characteristics of nitro-organics such as trinitro-toluene (TNT), dinitro-toluene (DNT) and nitrobenzene (NB) on granular activated carbon (GAC) were studied to understand their dynamic adsorption behaviour for dilute aqueous solutions. A model was developed to predict the dynamics of the adsorption process and the effect of various design and operating parameters on adsorption characteristics. The model predictions would provide inputs to design of bench scale and pilot plant scale experiments. Section 2 of the paper describes the assumptions, predictions, development of the model and its validation with experimental data generated during bench scale and pilot plant trials. Section 3 presents the breakthrough characteristics obtained by conducting experimental runs for GAC of different surface areas from 650 to 1500 m(2)/g, hydraulic loading rates (HLR) ranging between 12 and 24 m(3)/h/m(2), feed concentrations from 50 to 130 mg/l and bed heights between 300 and 1000 mm for TNT, DNT and NB solutions. The effect of these independent parameters on the breakthrough time, adsorption capacity and the minimum concentration achieved in the effluent was studied and the results obtained are presented in this paper. These indicate that the adsorption capacity goes though a maximum when studied as a function of HLR and feed concentration. The adsorption capacity per unit surface area also shows a maximum around 1000 m(2)/g. The minimum bed height required for meeting environmental effluent discharge limit of 1 ppm was experimentally found to be about 800 mm. These results compare well with the predictions based on the model developed for column adsorption process. Data from these experimental runs and the model predictions have been used to optimise various parameters for the design of a pilot plant unit with 200 l per hour capacity.

Neurotransmitter/neuropeptide interactions in the regulation of neurohypophyseal hormone release.

Regulation of neurohypophyseal hormone release reflects the convergence of a large number of afferent pathways on the vasopressin (VP)- and oxytocin-producing neurons. These pathways utilize a broad range of neurotransmitters and neuropeptides. In this review, the mechanisms by which this information is coordinated into appropriate physiological responses is discussed with a focus on the responses to agents that are coreleased from A1 catecholamine nerve terminals in the supraoptic nucleus. The A1 pathway transmits hemodynamic information to the vasopressin neurons by releasing several neuroactive agents including ATP, norepinephrine, neuropeptide Y, and substance P. These substances stimulate VP release from explants of the hypothalamo-neurohypophyseal system and certain combinations of these agents elicit potent but selective synergism. Evaluation of the signal cascades elicited by these agents provides insights into mechanisms underlying these synergistic interactions and suggests mechanisms responsible for coordinated responses of the VP neurons to activation of a range of ion-gated ion channel and G-protein-coupled receptors.

Substance P and NPY differentially potentiate ATP and adrenergic stimulated vasopressin and oxytocin release.

The supraoptic nuclei are innervated by the A1 neurons of the caudal ventrolateral medulla. Substances colocalized in the A1 terminals include norepinephrine (NE), substance P (SP), ATP, and neuropeptide Y (NPY). ATP, acting at P(2x) receptors, caused rapid and unsustained stimulation of vasopressin (VP) and oxytocin (OT) release from perifused explants of the hypothalamo-neurohypophysial system. SP elicited a concentration-dependent stimulation of VP and OT release that was large and sustained compared with other stimuli. ATP, but not phenylephrine (PE, alpha(1)-adrenergic agonist), augmented the response to SP (1 microM). In contrast, NPY did not alter basal nor ATP-induced VP or OT release, but it did cause sustained potentiation of PE-induced VP and OT release. The Y(1)-agonist, [Leu(31),Pro(34)]-NPY, increased VP and OT release, suggesting that the ineffectiveness of NPY reflects opposing actions at pre- and postsynaptic receptors. However, [Leu(31),Pro(34)]-NPY did not potentiate hormone responses to ATP or PE. The differential responses to these colocalized neurotransmitters and neuropeptides illustrate the range of potential responses that stimulation of this pathway might elicit from supraoptic neurons.

'Free omental plug': a nostalgic look at an old and dependable technique for giant peptic perforations.

Peptic perforation is a serious complication of peptic ulcer disease. The defect in the intestinal wall usually does not present a difficult technical problem of surgical management, in most cases perforation can be closed primarily. On rare occasions an extremely large defect (giant peptic perforation - defined as any perforation greater than 2.5 cm in size) cannot be closed by these simple techniques. Modalities of treatment advocated for such an ulcer over the years are: free omental plug in the form of a mushroom; serosal patch technique; jejunal pedicle graft, partial gastrectomy, and finally the possible addition of proximal gastrojejunostomy. The omental plug is a simple procedure which does not require expertise and can even be performed in a very short time by a trainee general surgeon in a seriously ill patient in emergency. We review 7 cases of giant peptic perforations closed by a free omental plug.

Anorectal avulsion: an unusual rectal injury.

Traumatic injuries to the rectum although uncommon can result in virulent complications and even death. Diverting colostomy, presacral drainage, distal wash out and rectal repair, when feasible, have become the standard treatment for rectal injuries. We report an unusual case of rectal injury resulting in anorectal avulsion from skin and surrounding tissues.

Purinergic and adrenergic agonists synergize in stimulating vasopressin and oxytocin release.

The A1 catecholamine neurons of the caudal ventrolateral medulla transmit hemodynamic information to the vasopressin (VP) neurons in the hypothalamus. These neurons corelease ATP with norepinephrine. Perifused explants of the hypothalamoneurohypophyseal system were used to investigate the role of these substances on VP release. ATP (100 micrometer) increased VP release 1.5-fold (p = 0.027). The response was rapid but unsustained. It was blocked by the P(2) receptor antagonist pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid (PPADS). The alpha(1)-adrenergic agonist phenylephrine (PE; 100 micrometer) also increased VP release by 1.5-fold (p = 0.014). Again, the response was rapid and unsustained. However, simultaneous perifusion of explants with ATP (100 micrometer) and PE (100 micrometer) resulted in a threefold to fourfold increase in VP release, which was sustained for as long as 4 hr. There was a similar synergistic effect of ATP and PE on oxytocin release. Interestingly, the synergistic response was delayed approximately 40 min relative to the response to either agent alone. Several experiments were performed to elucidate the cellular mechanisms of this synergism. The effect was blocked by PPADS, a protein kinase C inhibitor (bisindolylmaleimide I HCl), and actinomycin, an inhibitor of gene transcription. These data suggest that P(2X) receptor activation, PKC-mediated phosphorylation, and gene transcription are required for the synergistic response. The marked synergism of these coreleased agents is probably important to achieve sustained increases in plasma VP in response to prolonged hypotension. These observations may also have broad applications to CNS function, because ATP may be coreleased at noradrenergic synapses throughout the CNS.

Simple and sensitive spectrophotometric determination of ziram, zineb and ferbam in commercial samples and foodstuffs using phenylfluorone.

A procedure has been developed for the determination of ziram, zineb and ferbam dithiocarbamate pesticides by converting ziram and zineb into a zinc-phenylfluorone complex and ferbam into an iron phenylfluorone complex, which are then dissolved in water in the presence of cetylpyridinium bromide and pyridine as a surfactant. The method is sensitive, highly selective and can be used for the determination of ziram, zineb and ferbam in commercial samples and in foodstuffs.

Primary extradural spinal melanoma.

Primary spinal melanoma is uncommon, with only 36 cases reported in the available literature. These lesions usually occur as diffuse melanomatosis. Solitary lesions are rare. Extradural locations is extremely rare, with only tow case reports in the literature. One such patient is reported and relevant literature reviewed.

Spectrophotometric determination of maneb by ternary complex formation with PAR and CTAB.

A rapid, simple, direct, and sensitive method has been developed for the determination of maneb (manganese ethylenebisdithiocarbamate) based on the formation of manganese-4-(2'-pyridylazo) resorcinol complex by a ligand displacement reaction, which is rendered water soluble by a cationic surfactant cetyltrimethylammonium bromide (CTAB) by the formation of an ion association complex. Beer's law is obeyed over the concentration range 0.08-2.4 mug/ml of the final solution at 500 nm in pH range 8-12. The molar absorptivity and Sandell's sensitivity are calculated to be 8.84 x 10(4) l.mol(-1).cm(-1) and 0.003 mug/cm(2), respectively. The developed method has been applied to the determination of maneb in commercial formulations, synthetic mixture, grain samples and vegetables.