Inhibiting sorbent stripping by designing a sorbent-packed porous probe for headspace solid-phase microextraction.

To prevent the stripping of coating sorbents in headspace solid-phase microextraction, a porous extraction probe with packed sorbent was introduced by using a porous stainless steel needle tube and homemade sol-gel sorbents. The traditional stainless-steel needle tube was punched by a laser to obtain two rows of holes, which supply a passageway for analyte vapor during extraction and desorption. The sorbent was prepared by a traditional sol-gel method with both poly(ethylene glycol) and hydroxy-terminated silicone oil as coating ingredients. Eight polycyclic aromatic hydrocarbons and six benzene series compounds were used as illustrative semi-volatile and volatile organic compounds in sequence to verify the extraction performance of this porous headspace solid-phase microextraction probe. It was found that the analysis method combining a headspace solid-phase microextraction probe and gas chromatography with mass spectrometry yielded determination coefficients of no less than 0.985 and relative standard deviations of 4.3-12.4%. The porous headspace solid-phase microextraction probe showed no decrease of extraction ability after 200 uses. These results demonstrate that the packed extraction probe with porous structure can be used for headspace solid-phase microextraction. This novel design may overcome both the stripping and breakage problems of the conventional coating fiber.

Cholesteryl ester transfer protein levels and gene deficiency in Chinese patients with cardio-cerebrovascular diseases / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To detect cholesteryl ester transfer protein (CETP) levels, frequencies of CETP D442G and I 14A mutations and characteristics of abnormal lipids in patients with cardio-cerebro vascular diseases.</p><p><b>METHODS</b>Ninety-four myocardial infarction (MI) patients, 110 stroke patients and 335 healthy controls were selected. The CETP concentration was determined using ELISA. The CETP activity was measured using a substrate of (14)C-radiolabeled discoidal bilayer particles. The CETP gene mutations were detected by PCR-RFLP.</p><p><b>RESULTS</b>The CETP concentrations in the MI and stroke group, were higher than those in the controls. The gene mutation frequencies of D442G in the MI, stroke and control group were 3.5%, 3.6% and 5%, respectively, and the frequencies of I 14A were 1.05%, 0.91% and 1%, respectively. One case of D442G homozygote was detected in the healthy group. The frequency of two CETP gene mutations showed no significant difference among the patients and controls. The CETP concentration and activity in subjects with CETP mutations were one-third of those in the control group. The level of HDL-C, apo-A1 increased in the mutation subjects, while the TG level decreased.</p><p><b>CONCLUSIONS</b>The CETP level increased significantly in patients with cardio-cerebrovascular diseases. The carriers of CETP deficiency had CETP and lipid abnormalities.</p>

CLINICAL SIGNIFICANCE OF ANALYSIS OF URINE TRACE PROTEINS AND PROTEIN CONSTITUENTS OF CASTS IN ESSENTIAL HYPERTENSION PATIENTS / 解放军医学杂志

The trace Alb, IgG, and IgM in urine were determined with ELISA, and urinary casts protein romposition was analysed by means of immunoenzyme stain methods, in 123 cases of primary hypertension patients. A significant high level of urine Alb and Ig were found in these patients, and a positive correlation existed between urinary trace proteins and disease severity, blood pressure and disease course. These increased proteins fell to normal level after giving treatment. Besides TH (Tamm-horsfall glycoprotein), no IgG, IgA, IgM and Alb were detected in urinary casts. These results suggested that the conbined use of both methods would be benefirial to distinguish primary hypertension from renal hypertension as well as to make early prognosis and monitor of renal function.