Die katalytische Wirkung des Isopestox auf die Chemiluminescenz des Luminols und die Inhibition dieser Reaktion

Ispitivano je kvantitativnim fotoelektričnim mjerenjima intenziteta emitiranog svijetla katalitičko djelovanje izopestoksa na kemiluminescenciju luminola u prisutnosti vodikova peroksida u lužnatim otopinama. Izopestoks u razmjerno malenim koncentracijama znatno povećava intenzitet Iuminescencije luminola. Određena je Michaelisova konstanta za tu reakciju, koja se može smatrati modelnom reakcijom enzimatskog (peroksidativnog) djelovanja organofosfornog spoja izopestoksa. Različite anorganske, odnosno organske tvari,djeluju efektorno na kemiluminescenciju luminola, koja je katalizirana dodavanjem izopestoksa. Efektorno djelovanje tuđih tvari (anorganskih soli, polifenola i aromatskih amina) većinom se manifestira kao inhibicija (gašenje luminescencije). Ima međutim i takvih tvari, koje znatno povisuju intenzitet luminescencije, odnosno koje u malenim koncentracijama povisuju, a u većim koncentracijama snizuju (gase) jakost luminescencije luminola. Značajno je, da izopestoks, kojem kao organofosfornom spoju pripada sposobnost da inhibira enzimatske reakcije, u konkretnom slučaju: djeluje in vitro identično kao i enzim peroksidaza, pri čemu vrijede glavni zakoni kinetike enzimatskih reakcija. Ali pri ispitivanju inhibicije ove reakcije dodavanjem tuđih tvari nisu potvrđene zakonitosti inhibicije enzimatskih reakcija. čini se, da je mehanizam luminolske reakcije tako zamršen, da tuđe tvari (efektori) u reakcijskoj smjesi mogu utjecati na tok reakcije u različitim smjerovima. Katalitički efekt izopestoksa na luminolsku reakciju može poslužiti za kvantitativno određivanje ove tvari primjenom fotoelektričnih mjerenja intenziteta luminescencije.Es wurde, durch photoelektrische Messungen der Intensität des ausgestrahlten Lichtes, die katalytische Wirkung des Isopestox auf die Chemiluminescenz des Luminols in Anwesenheit von Wasserstoffperoxyd in alkailischer Lösung untersucht. Isopestox erhöht in verhältnismässig geringer Konzentration wesentlich die Intensität der Luminiscenz des Luminols. Es wunde die Michaeliskonstante dieser Reaktion, die als Modellreaktion der enzymatischen Wirkung (Peroxydasewirkung) der Organe-phosphorverbindung Isopestox aufgefasst werden kann, bestimmt. Verschiedene anorganische und organische Stoffe wirken effektorisch auf die durch Isopestox katalysierlte Chemiluminescenz des Luminols. Die Effektorenwirkung der Fremdstoffe (anorganische Salze, Polyphenole, aromatische Amine) manifestiert sich zum grossen Teil als Inbibition (Löschung der Luminescenz]. Es gibt aber auch Stoffe, welche die Intensität der Luminescenz wesentlich erhöhen, oder die in kleiner Konzentration die Iutesidät der Luminescenz erhöhen, in grösserer Konzentration jedoch herabsetzen (löschen). Es ist von besonderem Interesse, dass das Isopestox, dem als Organophosphorverbindung die Fähigkeit zukommt enzymatische Reaktionen zu inhibieren, im konkreten Falle in vitro genau so wirkt wie das Enzym Peroxydase, wobei die wesentlichsten Gesetze der Kinetik enzymatischer Reaktionen Gültigkeit besitzen. Bei der näheren Prüfung der Inhibition dieser Reaktion durch Fremdstoffzusatz wurde jedoch Festgestellt, dass die Gesetemässigkeiten der Inhibition enzymatischer Reaktionen in diesem Ealle offenbar nicht erfüllt sind. Es kann angenommen werden, dass infolge des sehr komplexen Mechanismus der Luminolreaktion die Fremdstoffe (Effektoren) im Reaktionsgemisch in verschiedenen Richtungen wirksam sein können. Die katalytische Wirkung des Isopestox auf die Luminolreaktion kann zur quantitativen Bestimmung dieses Stoffes, mit Hilfe von lichtelektrischen Messungen der Lurninescenzintensität, benützt werden

Chronic bilateral heel pain in a child with Sever disease: case report and review of literature

We are presenting a case report of a 10-year-old male with a 1 year history of bilateral heel pain. Sever disease is self limiting condition of calcaneal apophysis. It is the most common cause of heel pain in the growing child. There is no documented case of this condition in this region. This case highlights the clinical features of this self limiting disorder as seen in this patient and reviews the current literature

The Effects of Serotonin Receptor Antagonists on Contraction and Relaxation Responses Induced by Electrical Stimulation in the Rat Small Intestine

Background: The main source of 5-HT in body is in enterchromafin cells of intestine, different studies mentioned different roles for endogenous 5-HT and receptors involved and it is not clearified the mechanism of action of endogenous 5-HT. Objectives: To study the role of endogenous 5-HT on modulation of contraction and relaxation responses induced by electrical field stimulation (EFS) in different regions of the rat intestine. Materials and Methods: Segments taken from the rat duodenum, jejunum, mid and terminal ileum were vertically mounted, connected to a transducer and exposed to EFS with different frequencies in the absence and presence of various inhibitors of enteric mediators i. e. specific 5-HT receptor antagonists. Results: EFS-induced responses were sensitive to TTX and partly to atropine, indicating a major neuronal involvement and a cholinergic system. Pre-treatment with WAY100635 (a 5-HT1A receptor antagonist) and granisetron up to 10.0 µM, GR113808 (a 5-HT4 receptor antagonist), methysergide and ritanserin up to 1.0 µM, failed to modify responses to EFS inall examined tissues. In the presence of SB258585 1.0 µM (a 5-HT6 receptor antagonist) there was a trend to enhance contraction in the proximal part of the intestine and reduce contraction in the distal part. Pre-treatment with SB269970A 1.0 µM (5-HT7 receptor antagonist) induced a greater contractile response to EFS at 0.4 Hz only in the duodenum. Conclusions: The application of 5-HT1A, 5-HT2, 5-HT3, 5-HT4, 5-HT6 and 5-HT7 receptor antagonists, applied at concentrations lower than 1.0 µM did not modify the EFS-induced contraction and relaxation responses, whichsuggests the unlikely involvement of endogenous 5-HT in mediating responses to EFS in the described test conditions. Keywords: Electric Stimulation Therapy; Serotonin 5-HT1 Receptor Antagonists; Intestine, Smal

Duration of shedding of respiratory syncytial virus in a community study of Kenyan children

Background: Our understanding of the transmission dynamics of respiratory syncytial virus (RSV) infection will be better informed with improved data on the patterns of shedding in cases not limited only to hospital admissions. Methods: In a household study, children testing RSV positive by direct immunofluorescent antibody test (DFA) were enrolled. Nasal washings were scheduled right away, then every three days until day 14, every 7 days until day 28 and every 2 weeks until a maximum of 16 weeks, or until the first DFA negative RSV specimen. The relationship between host factors, illness severity and viral shedding was investigated using Cox regression methods. Results: From 151 families a total of 193 children were enrolled with a median age of 21 months (range 1-164 months), 10% infants and 46% male. The rate of recovery from infection was 0.22/person/day (95% CI 0.19-0.25) equivalent to a mean duration of shedding of 4.5 days (95%CI 4.0-5.3), with a median duration of shedding of 4 days (IQR 2-6, range 1-14). Children with a history of RSV infection had a 40% increased rate of recovery i.e. shorter duration of viral shedding (hazard ratio 1.4, 95% CI 1.01-1.86). The rate of cessation of shedding did not differ significantly between males and females, by severity of infection or by age. Conclusion: We provide evidence of a relationship between the duration of shedding and history of infection, which may have a bearing on the relative role of primary versus re-infections in RSV transmission in the community

Src Dependent Pancreatic Acinar Injury Can Be Initiated Independent of an Increase in Cytosolic Calcium

Several deleterious intra-acinar phenomena are simultaneously triggered on initiating acute pancreatitis. These culminate in acinar injury or inflammatory mediator generation in vitro and parenchymal damage in vivo. Supraphysiologic caerulein is one such initiator which simultaneously activates numerous signaling pathways including non-receptor tyrosine kinases such as of the Src family. It also causes a sustained increase in cytosolic calcium- a player thought to be crucial in regulating deleterious phenomena. We have shown Src to be involved in caerulein induced actin remodeling, and caerulein induced changes in the Golgi and post-Golgi trafficking to be involved in trypsinogen activation, which initiates acinar cell injury. However, it remains unclear whether an increase in cytosolic calcium is necessary to initiate acinar injury or if injury can be initiated at basal cytosolic calcium levels by an alternate pathway. To study the interplay between tyrosine kinase signaling and calcium, we treated mouse pancreatic acinar cells with the tyrosine phosphatase inhibitor pervanadate. We studied the effect of the clinically used Src inhibitor Dasatinib (BMS-354825) on pervanadate or caerulein induced changes in Src activation, trypsinogen activation, cell injury, upstream cytosolic calcium, actin and Golgi morphology. Pervanadate, like supraphysiologic caerulein, induced Src activation, redistribution of the F-actin from its normal location in the sub-apical area to the basolateral areas, and caused antegrade fragmentation of the Golgi. These changes, like those induced by supraphysiologic caerulein, were associated with trypsinogen activation and acinar injury, all of which were prevented by Dasatinib. Interestingly, however, pervanadate did not cause an increase in cytosolic calcium, and the caerulein induced increase in cytosolic calcium was not affected by Dasatinib. These findings suggest that intra-acinar deleterious phenomena may be initiated independent of an increase in cytosolic calcium. Other players resulting in acinar injury along with the Src family of tyrosine kinases remain to be explored. © 2013 Mishra et al

Metabolomic and transcriptomic stress response of Escherichia coli

GC-MS-based analysis of the metabolic response of Escherichia coli exposed to four different stress conditions reveals reduction of energy expensive pathways.Time-resolved response of E. coli to changing environmental conditions is more specific on the metabolite as compared with the transcript level.Cease of growth during stress response as compared with stationary phase response invokes similar transcript but dissimilar metabolite responses.Condition-dependent associations between metabolites and transcripts are revealed applying co-clustering and canonical correlation analysis

Event-related potential studies of post-traumatic stress disorder: a critical review and synthesis

Despite the sparseness of the currently available data, there is accumulating evidence of information processing impairment in post-traumatic stress disorder (PTSD). Studies of event-related potentials (ERPs) are the main tool in real time examination of information processing. In this paper, we sought to critically review the ERP evidence of information processing abnormalities in patients with PTSD. We also examined the evidence supporting the existence of a relationship between ERP abnormalities and symptom profiles or severity in PTSD patients. An extensive Medline search was performed. Keywords included PTSD or post-traumatic stress disorder, electrophysiology or EEG, electrophysiology, P50, P100, N100, P2, P200, P3, P300, sensory gating, CNV (contingent negative variation) and MMN (mismatch negativity). We limited the review to ERP adult human studies with control groups which were reported in the English language. After applying our inclusion-exclusion review criteria, 36 studies were included. Subjects exposed to wide ranges of military and civilian traumas were studied in these reports. Presented stimuli were both auditory and visual. The most widely studied components included P300, P50 gating, N100 and P200. Most of the studies reported increased P300 response to trauma-related stimuli in PTSD patients. A smaller group of studies reported dampening of responses or no change in responses to trauma-related and/or unrelated stimuli. P50 studies were strongly suggestive of impaired gating in patients with PTSD. In conclusion, the majority of reports support evidence of information processing abnormalities in patients with PTSD diagnosis. The predominance of evidence suggests presence of mid-latency and late ERP components differences in PTSD patients in comparison to healthy controls. Heterogeneity of assessment methods used contributes to difficulties in reaching firm conclusions regarding the nature of these differences. We suggest that future ERP-PTSD studies utilize standardized assessment scales that provide detailed information regarding the symptom clusters and the degree of symptom severity. This would allow assessment of electrophysiological indices-clinical symptoms relationships. Based on the available data, we suggest that ERP abnormalities in PTSD are possibly affected by the level of illness severity. If supported by future research, ERP studies may be used for both initial assessment and treatment follow-up

Consumption experience, choice experience and the endowment effect

We report experiments investigating how experience influences the endowment effect. Our experiments feature endowments which are bundles of unfamiliar consumption goods. We examine how a subject’s willingness to swap items from their endowment is influenced by prior experiences of tasting the goods in question and by prior experiences of choosing between them. We do not find a statistically significant endowment effect in our baseline treatment and, because of this, we are unable to test for an effect of consumption experience. We do find an endowment effect when the endowment is acquired in two instalments and, in this setting, we find some evidence that choice experience increases trading. In a follow up experiment, we find evidence that the absence of an endowment effect in our baseline treatment is due to subjects being more willing to swap when they do not have to give up the last unit of their endowment