Concentration dependent effects of commonly used pesticides on activation versus inhibition of the quince (Cydonia Oblonga) polyphenol oxidase

Polyphenol oxidase (PPO) catalyzes the oxidation of o-diphenols to their respective quinones which undergo autopolymerization and form dark pigments. The interaction of PPO with various substrates and effectors remains the focus of intensive investigations due to the enzyme’s key role in pigments biosynthesis including animal melanogenesis and fruit/fungi enzymatic browning. In this study, the effect of a range of commonly used pesticides on the enzyme activity has been evaluated using the purified quince (Cydonia oblonga Miller) PPO. The biochemical analysis showed that, in the presence of high pesticide concentrations, the enzyme was competitively inhibited, particularly with benomyl, carbaryl, deltamethrine and parathion methyl for which inhibition constants (K_i) were 8.3, 5.7, 12 and 4 μM, respectively. At lower pesticide concentrations (2–10 μM), however, the catecholase activity was significantly activated (p < 0.01), suggesting a homotropic behavior of these chemical compounds. Furthermore, the use of in silico structure-based analyses, known as computational docking, highlighted the nature of the PPO-pesticides interactions and confirmed the in vitro observations. Catechol substrate and parathion methyl inhibitor showed lower total energy scores of −120.06 and −117.43 kcal mol⁻¹, indicating that these ligands had higher PPO-binding affinities. The obtained data bring to light new pesticide functional features of great interest in the medicinal, agro-chemical and environmental circles.     

Carbendazim impends hepatic necrosis when combined with imazalil or cypermethrin

Imazalil, cypermethrin and carbendazim are detected in plants for human nutrition. To explore whether their combinations, applied orally in low doses, would induce changes in metabolic patterns and hepatotoxicity, a subchronic in vivo experiment was conducted. Doses of 10mg/kg of imazalil (im) and cypermethrin (cy) and 20 mg/kg of carbendazim (car) and their combinations (im, 10 mg/kg+cy, 10mg/kg; im, 10mg/kg+car, 20mg/kg; car, 20 mg/kg + im, 10 mg/kg) were given to Swiss mice daily over 28 days. After 24 hr from the last dose, the relationships of cytotoxicity biomarkers were analysed: serum lactate dehydrogenase, aspartate transaminase, alanine transferase, amylase, alkaline phosphatase, creatine kinase, creatinine and total proteins. Individual pesticides showed different toxic potential (cy>im car) generally characterized by increase in enzyme activities. Histological analysis showed that cypermethrin, but not imazalil or carbendazim, alone can cause mild necrosis. Combinations generally caused decrease in the activity of enzymes, indicating liver damage. Low doses of carbendazim in combination with low doses of imazalil or cypermethrin caused very pronounced hepatic necrosis, more than any of the three individually applied pesticides or combination of imazalil and cypermethrin. In fruits and vegetables for human consumption, residues of these three pesticides and prolonged combined intake of low doses, which by themselves acutely would not cause any effect, may have similar hepatotoxic effects.     

Effects of clozapine and olanzapine on cytokine systems are closely linked to weight gain and drug-induced fever

The second generation antipsychotics clozapine and olanzapine are known to cause weight gain. However, only clozapine is associated with drug-induced fever. Cytokines have been linked to the induction of both weight gain and drug-induced fever. We investigated these potential side effects of clozapine and olanzapine and studied their differential effects on cytokine secretion. Thirty patients suffering from schizophrenia, schizophreniform disorder or schizoaffective disorder were treated with either clozapine (mean modal dose: 266.7+/-77.9mg) or olanzapine (21.2+/-2.5mg) in a randomized, double-blind, 6-week study. Body mass index (BMI), tympanic temperature, and plasma levels of leptin and cytokines (tumor necrosis factor-alpha (TNF-alpha), soluble TNF receptor 1 and 2 (sTNFR-1/2), soluble interleukin-2 receptors (sIL-2R), interleukin-6) were determined weekly. BMI, leptin and cytokines significantly increased over time, except interleukin-6 and sTNFR-1 in the olanzapine group. All cytokines numerically increased compared to baseline already during the first week of treatment in both groups. Leptin, TNF-alpha, sTNFR-1, sTNFR-2 and sIL-2R levels correlated with the BMI. Five patients who received clozapine (33%) developed drug-induced fever (>/=38 degrees C). In these, interleukin-6 peak levels were significantly (p<0.01) higher than in those patients treated with clozapine who did not develop fever. In conclusion, increase of BMI appears to be related to clozapine's and olanzapine's similar effects on cytokine systems, whilst drug-induced fever appears to be related to clozapine's differential effects on interleukin-6.     

Novel pharmacological chaperones that correct phenylketonuria in mice

Phenylketonuria (PKU) is caused by inherited phenylalanine-hydroxylase (PAH) deficiency and, in many genotypes, it is associated with protein misfolding. The natural cofactor of PAH, tetrahydrobiopterin (BH(4)), can act as a pharmacological chaperone (PC) that rescues enzyme function. However, BH(4) shows limited efficacy in some PKU genotypes and its chemical synthesis is very costly. Taking an integrated drug discovery approach which has not been applied to this target before, we identified alternative PCs for the treatment of PKU. Shape-focused virtual screening of the National Cancer Institute's chemical library identified 84 candidate molecules with potential to bind to the active site of PAH. An in vitro evaluation of these yielded six compounds that restored the enzymatic activity of the unstable PAHV106A variant and increased its stability in cell-based assays against proteolytic degradation. During a 3-day treatment study, two compounds (benzylhydantoin and 6-amino-5-(benzylamino)-uracil) substantially improved the in vivo Phe oxidation and blood Phe concentrations of PKU mice (Pah(enu1)). Notably, benzylhydantoin was twice as effective as tetrahydrobiopterin. In conclusion, we identified two PCs with high in vivo efficacy that may be further developed into a more effective drug treatment of PKU.     

Pollicization of the index finger in hypoplasia of the thumb. Experience with the method of Buck-Gramcko and retrospective analysis of the clinical outcome in a series of 19 pollicizations

Background

In congenital malformation of the thumb index finger pollicization is a proven method for constructing a new thumb all over the world.

Methods

A series of 19 pollicizations in 15 patients is presented. In all cases of index finger pollicization the method of Buck-Gramcko is used and the functional outcome is evaluated after Percival’s method. Three special cases are described in detail and the preoperative evaluation with a CT-angiography in cases of complex malformations (case 3) for better planning of the surgical steps is recommended. The importance of parent’s information soon after giving birth to a child with thumb hypoplasia is described in detail as the postoperative management.

Results

In children with bilateral deformities of the hand the surgery can be performed in one session, in only 2 cases a second operation was necessary. The postoperative results were excellent and good (Percival’s measurement) and the children are now able to perfectly use their affected hand in their day-to-day activities.

Conclusion

Buck-Gramcko’s method of pollicization in congenital thumb malformation gives excellent results. The preoperative planning and exactly following the four key steps is as important as the postoperative management.     

Evaluation of the Konelab 20XT clinical chemistry analyzer.

The Konelab 20XT (Thermo Electron Oy, Finland) is a clinical chemistry analyzer for colorimetric, immunoturbidimetric and ion-selective electrode measurements. The aim of our work was to evaluate the analytical performances of the Konelab 20XT according to the European Clinical Chemistry Laboratory Standards Guidelines. A total of 30 analytes including substrates, enzymes, electrolytes and specific proteins were tested. Investigation results showed low imprecision (within-run coefficient of variation was below 3.5% and between-day coefficient of variation was less than 2.5% for most analytes at all three levels studied) and acceptable accuracy of the analyzer. No significant sample- or reagent-related carry-over was found. It was demonstrated that the analytical system operates within the claimed linearity ranges. The results compared well with those obtained by instruments routinely used in our laboratory (Olympus AU2700, Behring Nephelometer II). In general, the data on interference by hemoglobin, hyperbilirubinemia and turbidity are in accordance with known facts. However, slight hemolysis was found to interfere with the alkaline phosphatase (ALP) assay and mild lipemia affected the glucose assay. The Konelab 20XT is an easy-to-use analyzer that is suitable for routine and emergency analyses in small laboratories.     

Tramadol premedication in operative extraction of the mandibular third molar: a placebo-controlled crossover study

Anxiolytic drugs are widely used for premedication in oral surgery. Since anxiety is usually associated with the fear of pain, we tested the effects of the analgesic tramadol in premedication before operative extraction of the mandibular third molar under local anesthesia. In a double-blind crossover study, 20 patients were randomized to receive 100?mg oral tramadol or placebo 1?h before operation. Anxiety, nausea, dryness of the mouth, pain and discomfort were recorded before administration of the drug, immediately before and after operation, and 0.5, 1, and 2?h postoperatively using ungraded 0–100?mm VAS scales. Blood pressure and heart rate were measured at the same times; vigilance was tested using the Maddox Wing Test and sensorimotor performance using the Trieger Dot Test; hemoglobin oxygen saturation (SpO₂) was measured using a pulse oximeter. In addition, SpO₂ and heart rate were recorded continuously in nine patients using a pulse oximeter connected to a computer. The surgeon assessed the quality of operating conditions on the VAS scale. Tramadol delayed and decreased the need of analgesics on the day of operation (p<0.05). The operating conditions were better in patients on tramadol premedication than in those on placebo during the first operation (p<0.05), but no differences were seen in patient well-being between treatments. The second operation was less stressful than the first. Tramadol is recommended only with special indications for premedication of patients undergoing third molar extraction under local anesthesia.     

Simultaneous exposure to airborne flour particles and thermal load as cause of respiratory impairment

Summary In order to estimate whether only simultaneous exposure to both airborne flour particles and unfavorable thermal environment alone cause the development of nonspecific respiratory disease or whether sole exposure to flour aerosols is likely to cause impairment of the respiratory system, a group of 80 millers and 130 bakers, all nonsmokers, were examined. Both millers and bakers were exposed to approximately the same concentration of airborne flour particles but the latter worked under considerable thermal load. It was found that between millers and bakers the difference in the prevalence of respiratory symptoms was not statistically significant. Although the differences between the mean measured and the mean predicted ventilatory function parameters (FVC, FEV₁, PEF, MEF 50%, MEF 75%) were significant both in millers and bakers, they did not differ significantly between these two groups. This finding suggests that exposure to flour dust may cause the development of chronic nonspecific respiratory disease and a reduction of ventilatory lung capacity irrespective of simultaneous heat load.