Portable fiber-optic immunosensor for detection of methsulfuron methyl.

This fiber optic sensor, based on competitive immunoreactions between coating-haptens and free haptens in solutions with corresponding antibodies, was developed to determine the concentration of the free hapten, methsulfuron-methyl. The ovalbumin (OVA)-methsulfuron-methyl conjugate was immobilized on a microscope slide. Horseradish peroxidase (HRP) labeled goat anti-rabbit IgG was used to generate an optical signal. The portable optical device consisted of a 0.25-W tungsten-halogen light source and a photosensitive diode detector. A typical competitive-binding calibration curve was seen between 0.3 and 100 ng/ml of methsulfuron-methyl. The detection limit for methsulfuron-methyl was 0.1 ng/ml.

[Study on the separation of optical chromatography].

The relationship between the particle radius with the intensity of the applied laser radiation force is theoretically studied using a ray-optics model by analyzing the forced-status of the separated particles in the mobile phase. The laser radiation force is proportional to the square of the particle radius when the particle radius is much smaller than the laser beam radius under the condition of using a single-transverse-mode laser beam with a Gaussian intensity distribution and the particle refractive index being larger than that of the mobile phase. The retention distance is calculated and the dynamic range is discussed. Theoretically, the dynamic range of the optical chromatography can be extended by increasing laser power, decreasing the flow rate of mobile phase and focusing the laser beam.

Helicobacter pylori infection and risk of peptic ulcer among cirrhotic patients.

There is a higher prevalence of peptic ulcer disease in cirrhotic patients than in the general population. Whether Helicobacter pylori is a risk factor for peptic ulcer in cirrhosis remains controversial. The aim of this study was to determine whether there is a significant correlation between H.pylori infection and peptic ulcer in liver cirrhosis. In a cross-sectional study, 49 cirrhotic patients underwent upper gastrointestinal endoscopy and 75 controls (health examinees) without liver disease were also examined by endoscopy. The presence of H. pylori was assessed by culture, histologic findings and rapid urease test of gastric antrum biopsy specimens. Thirty of the 49 (61%) cirrhotic patients had peptic ulcers as compared to 24 of the 75 (32%) controls. The frequency of H. pylori in the antrum in the cirrhotic group was significantly lower than in the control group (39% vs 69%). The presence of H. pylori was more frequent in control patients with gastric (75%) and duodenal ulcers (95%) than nonulcer control patients (59%) whereas the difference between patients with peptic ulcer and nonulcer (40% vs 37%) was not significant in cirrhotic patients. H. pylori was identified in 40% of the cirrhotic patients with duodenal ulcers compared with 95% of controls with duodenal ulcers (p < 0.05). Nevertheless, this difference was not significant among patients with a gastric ulcer between the two groups (40% vs 75%). There was no significant difference in the frequency of H. pylori infection among nonulcer patients between the cirrhotic and control groups (37% vs 59%). In conclusion, we found no evidence to substantiate an etiologic role of H. pylori in the development of a duodenal ulcer in cirrhotic patients.

[Two new steroidal saponins from Allium sativum and their inhibitory effects on blood coagulability].

Six compunds were isolated from the fresh bulbs of Allium sativum L (garlic). Their structures were elucidated as proto-iso-eruboside-B (I), eruboside-B (II), iso-eruboside-B (III), sativioside C (IV), adenosine (V) and tryptophan (VI). I and III are new steroidal saponins. This paper deals with the structural determination of I and III and their effects on platelet aggregation, blood coagulation and fibrinolysis in vitro.