Cyclopiazonic acid增加SHR和WKY血管平滑肌细胞Ca~(2+)-依赖性外向K~+-电流

采用全细胞及细胞贴附式斑片钳技术记录自发性高血压大鼠(SHR)和Wistar-Kyoto对照鼠(WKY)培养主动脉平滑肌细胞的Ca~(2+)-依赖性外向K~+电流[I_(k(Ca))],测定肌浆网Ca~(2+)泵抑制剂CPA对其影响.CPA能增加I_K(Ca))单通道开放时间,缩短关闭时间,增加全细胞I_(K(Ca))幅度,这些作用与Ca~(2+)相关并可被K~+通道阻断药glybenclamide阻断。CPA作用在SHR和WKY之间无明显差异。结果提示高血压状态下血管平滑肌的功能改变可能与I_(K(Ca))无关。     

Assessment of gastric acidity in intensive care patients: Intermittent pH registration cannot replace continuous pH monitoring

Objective To test the accuracy of colour-scaled indicator papers to measure pH values and to study the correlation between this method of measuring gastric juice pH once daily and 24-h continuous intragastric pH monitoring in intensive care patients.Design The accuracy of indicator papers was tested in the laboratory using colourless solutions and aspirated gastric juice and was then verified with a laboratory pH meter. Continuous intragastric pH monitoring was performed in mechanically ventilated ICU patients. Percentages of time with a pH value <3.0 and median pH values by 24-h continuous intragastric pH monitoring were compared to pH values measured once daily with indicator paper.Setting A mixed ICU.Patients A total of 150 measurements were taken by continuous pH monitoring in 91 mechanically ventilated ICU patients.Measurements and results The correlation between the pH measured with the indicator paper and subsequently verified with a laboratory pH meter in colourless solutions was 0.96 [regression coefficient (RC) 0.98, 95% confidence interval (CI) 0.91–1.05]. Measured in gastric juice it was 0.95 (RC 0.95, 95% CI 0.88–1.01). The correlation between median pH values, determined with 24-h continuous intragastric pH monitoring, and values measured with indicator papers was 0.39 (RC 0.43, 95% CI 0.26–0.59). The mean difference in pH, as determined by the analysis of Bland and Altman [22], was 0.9 with a SD of 4.7. The correlation between the percentage of time with pH<3.0, as obtained with continuous registration, and median gastric pH values (also obtained with continuous registration) was–0.94 (RC–0.06, 95% CI–0.06-–0.05); the correlation between the time and gastric pH values (measured with indicator paper) was–0.40 (RC–0.02, 95% CI–0.03-–0.02).Conclusion The colour-scaled indicator paper is an accurate method of measuring pH values, but there is a poor correlation between gastric pH values measured once daily and a total measurement derived from 24-h continuous intragastric pH monitoring. Changes in intragastric pH values cannot be accurately studied when measuring acidity once daily. The influence of various treatment regimens on intragastric acidity in relation to the development of gastric colonization and nosocomial pneumonia should be investigated either with continuous intragastric monitoring or with frequent measurements in aspirated gastric juice.This study was made possible by a grant (28-2125) from the Praevention Foundation     

Diffuse Conduction Abnormalities in an Adolescent with Familial Sinus Node Disease

We report a case of familial sinus node disease with associated conduction abnormalities in the atrioventricular node and distal conduction system Spontaneous atrial pacemaker activity was absent though the atrium could be depolarized. The pacemaker activity of the heart resided in the atrioventricular junction. The AV node showed impaired automaticity and abnormal conduction properties which partially improved after vagal blockage.     

Carriage of antibiotic-resistantEscherichia coli by healthy volunteers during a 15-week period

Summary Escherichia coli strains (n=678 and n=670) isolated from faecal samples from 90 and 93 healthy volunteers of two cities, Weert and Roermond respectively, were analysed for their susceptibility to 12 antimicrobial agents during a 15-week period. Significant differences between both cities in the distribution of the MIC values were observed for apramycin, chloramphenicol, kanamycin, neomycin, nitrofurantoin, sulfamethoxazole and trimethoprim. For Weert (n=678) the antibiotic resistance percentages varied from 0.4% for nalidixic acid to 26.7% for sulfamethoxazole. For Roermond (n=670) the figures varied from 0.6% for nitrofurantoin to 37.5% for sulfamethoxazole. Resistance to amoxicillin/clavulanate was not found in either city. The most frequent pattern was resistance to sulfamethoxazole only, followed by resistance to oxytetracycline, streptomycin and sulfamethoxazole. In each individual there was only a small variation in resistance patterns of the isolates, i. e. the majority had one (n=51) or two (n=63) patterns with a maximum of five during the 15-week period. A fully susceptible pattern was found in the strains from 38 individuals.

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Trägertum Antibiotika-resistenterEscherichia coli bei gesunden Freiwilligen während 15 Wochen

Zusammenfassung Stämme vonEscherichia coli, (n=678 und n=670), die aus Stuhlproben von jeweils 90 und 93 gesunden Freiwilligen aus zwei Städten, Weert und Roermond, gewonnen wurden, wurden auf ihre Empfindlichkeit gegenüber 12 antimikrobiellen Substanzen geprüft. Die Untersuchung lief über 15 Wochen. Für Apramycin, Chloramphenicol, Kanamycin, Neomycin, Nitrofurantoin, Sulfamethoxazol und Trimethoprim fanden sich zwischen den beiden Städten signifikante Unterschiede in den MHK-Werten. Für Weert (n=678) fanden sich Resistenzraten, die von 0,4% bei Nalidixinsäure bis 26,7% für Sulfamethoxazol reichten. In Roermond (n=670) variierten die Resistenzraten von 0,6% für Nitrofurantoin bis 37,5% für Sulfamethoxazol. In keiner der beiden Städte fand sich Resistenz gegenüber Amoxicillin-Clavulansäure. Als häufigstes Muster fand sich Resistenz gegen Sulfamethoxazol allein, es folgten Resistenz gegen Oxytetracyklin, Streptomycin und Sulfamethoxazol. Die intraindividuellen Resistenzmuster der Isolate variierten nur sehr wenig, das heißt, die meisten hatten Resistenz gegen ein (n=51) oder zwei (n=63) Antibiotika, maximal fünf während der 15 Wochen. Bei 38 Personen zeigten alle Stämme volle Empfindlichkeit gegen die Testsubstanzen.

     

Resistance transfer in mixed cultures of Staphylococcus aureus

Transfer of resistance markers was regularly observed in mixed cultures of pairs of constructed strains of Staphylococcus aureus. This transfer was shown to be due to general transduction and required a lysogenic donor strain, carrying a transducing phage of serotype B and a transducible plasmid, and an acceptor strain without either strong restriction or an incompatible plasmid. Transfer was sometimes bidirectional when both strains carried a transducing phage. Unidirectional transfer occurred when the acceptor strain was immune. When the acceptor was sensitive to the donor phage, reversed transfer of a marker from the acceptor to the donor could take place. The kinetics of transfer are governed by the rate of phage production, the rate of phage adsorption and the frequency of transduction. A mathematical model has been developed to describe the interplay of these factors. The numbers of transductants observed in mixed cultures agreed with those expected from the model. Transfer was also observed in mixed cultures of constructed strains and wild-type strains. Transfer between wild-type strains is also possible, but was not observed in many combinations because of lack of transducing phage, strong restriction or other factors. Transfer was also observed in local lesions in mice infected with two strains and in mixtures inoculated on to human skin.