Interlaboratory proficiency tests for the detection of staphylococcal enterotoxin type A in food.

Staphylococcal enterotoxins (SEs) are among the leading causes of food intoxications, affecting consumer health even in nanogram (ng) amounts. In the European Union, certain food safety criteria are specified, including the absence of SEs in cheeses, milk powder and whey powder. Until 2019, the analytical reference method used was the European Screening Method, which was replaced by EN ISO 19020. For the official laboratories involved in food control, the German Reference Laboratory for coagulase-positive staphylococci including Staphylococcus aureus organized three interlaboratory proficiency tests (ILPTs) to detect SE type A in food during the years 2013-2018. The selected food products (cream cheese and vanilla pudding) were successfully tested beforehand with regard to easy handling, homogeneity and stability of the added toxin. In 2013, ILPT participants overall were not competent in detecting SE type A in food. The following factors were identified to improve the performance: (i) concentration of sample extract using dialysis; (ii) selection of a sensitive detection kit; and (iii) proper sample handling. By taking these factors into account and instructing and training the laboratories, their competence greatly improved. In 2018, all performance criteria (specificity, sensitivity and accuracy) were >90%, even at very low concentrations of SE type A of approximately 0·01 ng g-1 food.

Potential of Hymenopteran larval and egg parasitoids to control stored-product beetle and moth infestation in jute bags.

The control of stored-product moths in bagged commodities is difficult because the developmental stages of the moths are protected by the bagging material from control measures such as the application of contact insecticides. Studies were carried out to assess the ability of Hymenopteran parasitoids to locate their hosts inside jute bags in the laboratory. The ability of different parasitoids to penetrate jute bags containing rice was investigated in a controlled climate chamber. Few Habrobracon hebetor (Say) (Hymenoptera: Braconidae) passed through the jute material while a high percentage of Lariophagus distinguendus (Förster), Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae), Theocolax elegans (Westwood) (Hymenoptera: Pteromalidae) and Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) were able to enter the Petri-dishes. Significantly more L. distinguendus and T. elegans entered compared to H. hebetor. There was significant difference in the mean percentage parasitoids invading depending on species. Head capsules and/or thorax widths were measured in order to determine whether the opening in the jute material would be large enough for entry of the parasitoids. These morphometric data differed depending on parasitoid species and sex. The parasitoid Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae) did not enter the bags, but located host larvae inside the jute bags and parasitized rice moths Corcyra cephalonica larvae by stinging through the jute material. Venturia canescens significantly reduced the number of C. cephalonica adults emerging from the bagged rice; therefore, it could be released in storage rooms containing bagged rice for biological control of C. cephalonica. The use of parasitoids to suppress stored-product insect pests in bagged commodities could become a valuable supplement to the use of synthetic pesticides.

Infarct size measurement by triphenyltetrazolium chloride staining versus in vivo injection of propidium iodide.

Infarct size delineation by triphenyltetrazolium chloride (TTC) staining is dependent on sufficient reperfusion. We therefore evaluated the possibility of using propidium iodide (PI), a reagent conventionally used in flow cytometry to fluorescently stain dead cells, for infarct size analysis after short periods of reperfusion. Forty-five rabbits were subjected to either 15 min, 2 h or 4.5 h of coronary artery occlusion without reperfusion, or to 15 min, 30 min and 2 h of coronary artery occlusion followed by 30 min, 1 h and 3 h of reperfusion. Fifteen min before terminating the experiment, PI was injected into the left atrium. Patent blue violet was used to delineate the area at risk. Following incubation in TTC, the area at risk was excised and cross sections obtained for microscopical infarct size quantification by PI fluorescence. PI fluorescence was absent after permanent occlusion and in control areas. Infarct sizes measured by TTC staining were significantly smaller after 1 h of reperfusion as compared to 3 h of reperfusion (30 min occlusion: 1+/-1 v 34+/-9%; P<0.05; 2 h occlusion: 9+/-6 v 47+/-8%; P<0.01). In contrast, infarct sizes determined by PI fluorescence reached values comparable to those measured by TTC staining or conventional histology after longer times of reperfusion already after 30 min of reperfusion (30 min occlusion: 35+/-16.5%; 2 h of occlusion: 61+/-8%). Therefore, after short times of reperfusion infarct size measurement by PI fluorescence is more reliable than by TTC staining.

[Acute theophylline intoxication as differential diagnosis of pneumothorax in an asthma patient]. / Akute Theophyllin-Intoxikation als Differentialdiagnose zum Pneumothorax beim Asthmapatienten.

The ambulance was called to a known asthmatic patient. On arrival, the team found a massively dyspnoeic, diaphoretic, non-cyanotic and somnolent patient. His medication consisted of oral theophylline (unknown dosage), fenoterol (metered-dose inhaler), as well as 8 mg oral prednisolone. On the day of emergency, the patient had been treated by two physicians who applied two doses of i.v. theophylline and one dose of s.c. terbutaline because of bronchoconstriction (dosage not documented). The patient's pulse was frequent with 200 beats/min, the blood pressure not measurable. Careful i.v. titration of metoprolol was started to decrease the patient's heart rate and increase diastolic filling and stroke volume. However, the patient showed a progressive circulatory collapse. Following diagnostic thoracocentesis to rule out a left-side pneumothorax, the patient required intubation and mechanical ventilation because of increasing cardiovascular instability. A tension pneumothorax developed immediately after mechanical ventilation and required rapid treatment with a chest tube. Nevertheless, CPR and intravenous infusion of catecholamines were necessary before the patient was referred to a medical intensive care unit where he died the same day in cardiogenic shock. Clinical signs and symptoms associated with an elevated theophylline plasma level make theophylline toxicity the probable causative event for the patient's emergency condition of acute theophylline intoxication.

Influence of the terminal complement-complex on reperfusion injury, no-reflow and arrhythmias: a comparison between C6-competent and C6-deficient rabbits.

OBJECTIVE: The complement system has been suggested to play a role in reperfusion injury which may result from an enhanced destruction of myocardial tissue or from an impairment of reflow. We investigated the influence of the C5b-9 complement complex on infarct size, reflow and arrhythmogenesis. METHODS: Twenty-eight C6-competent rabbits and 18 rabbits with congenital C6 deficiency were subjected to either 30 min or 2 h of coronary artery occlusion followed by reperfusion. C6 deficiency was confirmed by the complement titration test and immunohistology. The triphenyl tetrazolium chloride method was used to delineate infarct size. Reflow into infarcted areas was evaluated histologically after an in vivo injection of propidium iodide which served as an early fluorescence microscopic marker of damaged myocardium subjected to reflow. Continuous ECG monitoring allowed the recording of arrhythmias. RESULTS: After 30 min of coronary artery occlusion infarct size was significantly smaller in C6-deficient rabbits (5.0 +/- 2% of the risk region) as compared to C6-competent rabbits (28.4 +/- 8.5%, P = 0.0371). The extent of reflow into damaged myocardium was nearly the same in both animal groups at this time (38 +/- 9 vs. 39 +/- 7% of the risk region). After 2 h of coronary artery occlusion, infarct size was not different between both animal groups, but the extent of reflow into damaged myocardium was significantly smaller in C6-competent rabbits than in C6-deficient rabbits (25 +/- 4 vs. 40 +/- 4%; P = 0.0185). Two of the 18 C6-deficient rabbits had ventricular arrhythmias (Lown II-IV), none of which was fatal. Eleven of the 28 C6-competent animals had major ventricular arrhythmias which were fatal in 6 rabbits. CONCLUSIONS: These results suggest that the lytic C5b-9 complement complex leads to reperfusion injury in the early phase (30 min) of ischaemia, resulting in a larger infarct. After 2 h of ischaemia, complement activation enhances the no-reflow phenomenon but does not affect infarct size. Finally, the C6 status seems to influence the susceptibility to ventricular arrhythmias after coronary artery occlusion, independent of reperfusion.