Biomedical subjects

L J Zeng

Publications and source records attributed to L J Zeng.

6 recordsLinked to original sources

PubMed2005

Progressive decrease of proinsulin secretion in sulphonylurea-treated type 2 diabetes.

Progressive deterioration of beta-cell function is proposed as a disease-related factor of sulphonylurea (SU) failure in type 2 diabetes. If it gradually worsens over time then disease duration may mirror the progressive beta-cell deterioration. The aim of the present study is to assess whether or not disease duration is influential in remodelling the secretion pattern of insulin-like molecules and in glucose control of SU-treated type 2 diabetes. A research model is used to investigate proinsulin secreting capacity over time, using two groups of patients: i) disease duration <5 years (n=62), comprising SU responders (SUr; n=48) and SU failures (SUf; n=14); and ii) disease duration > or = 5 years (n= 37), comprising an SUr group (n=17) and an SUf group (n=20). Blood samples are taken at 0 h, 0.5 h 1 h, 2 h and 3 h during a standard oral glucose tolerance test and measured for glucose, total proinsulin (TPI), intact proinsulin (IPI) and specific insulin (SI) concentrations. Pairwise comparison of estimated marginal means of blood glucose, SI, IPI and TPI levels at each time point are carried out between groups and subgroups. (SUr vs. SUf). Homa insulin resistance index (IR index) is applied to analyse IR between the groups. It was found that patients with shorter disease duration had higher proinsulin (TPI and IPI) levels at all time points (P<0.05), together with a lower glucose level at 2 h and 3 h (P<0.05). Homa insulin index analysis showed no difference between the two groups (P=0.26). Results also showed that the SUr group had a significantly lower glucose level at Oh and 3h (P<0.05), although no significant difference in insulin and proinsulin levels was found between the SUr and SUf groups. In conclusion, proinsulin may play an important role in glucose control in SU-treated type 2 diabetes, but the effect is reduced in SUf patients.

Adult↗

PubMed2003

Secondary sulphonylurea failure: what pathogenesis is responsible?

Sulphonylurea (SU) stimulates insulin secretion by pancreatic beta-cells and is generally used as a first-line treatment for type 2 diabetes. However, after long-term SU treatment (six months or over), some patients begin to show an increase in blood glucose once again (secondary SU failure). Two theories have been put forward to explain this failure--dysfunction of the proinsulin conversion machinery or insulin resistance. However, the primary pathogenesis behind secondary SU failure still needs to be investigated. Using a reliable technique that specifically identifies intact proinsulin (IPI), total proinsulin (TPI) and specific insulin (SI), this study aims to discover if a defect in the proinsulin converting mechanism plays a role in SU failure. Three groups were recruited for this study: healthy controls (n=8), SU responders (n=38) and secondary SU failures (n= 46). Serum concentrations of insulin-related molecules released in response to a standard glucose challenge test were compared between the groups. It was found that total SI was lower in the patient groups (P<0.05 compared to the control group), while TPI and IPI showed no distinct difference between the three groups (P>0.05). TPI:SI ratio and IPI:SI ratio showed marked increases in the patient groups (P<0.05 compared to control group), with no obvious quantitative difference between SU responders and secondary SU failures (P>0.05). Similar results for the Homa Insulin Resistant Index were found between the two patient groups. Interestingly, blood glucose at 180 mins after glucose challenge was significantly higher in the secondary SU failure group (P<0.05), with no correlation to SI, while the SU responder group showed good correlation between the parameters (P<0.05). We conclude that type 2 diabetes is associated with obvious dysfunction in the proinsulin-converting process and shows severe SI deficiency in responding to glucose challenge. Dysfunction of the proinsulin conversion mechanism was not an extra cause responsible for SU failure.

Adult↗

PubMed2000

Cardiac troponin I: a marker for post-burn cardiac injury.

Cardiac troponin I (cTnI) was measured by chemiluminescent immunoassay following burn injury. Thirty patients [total body surface area (TBSA) of burn 15-98%] were included in this study and each had four to six blood samples collected at 2-day intervals between the 5th and 14th days post-burn. All patients were found to have increased cTnI on two or more occasions. The mean cTnI concentration was significantly higher in patients with TBSA of burn > 30% (0.34 microg/L compared with 0.09 microg/L, P<0.001) and in those with obvious burn wound exudation (0.32 microg/L compared with 0.12 microg/L, P<0.01). cTnI concentrations peaked at the time when there was obvious burn wound exudation or spontaneous separation of eschar, then decreased after surgical excision. Two patients with persistently high cTnI concentrations developed tachycardia. We conclude that burned patients have varying degrees of non-ischaemic cardiac injury, manifesting as leakage of cTnI from myocytes into the circulation.

Adolescent↗

PubMed2000

[Preliminary studies on chemotaxonomy of Caprifoliaceae L].

OBJECTIVE: To study the taxonomy of Caprifoliaceae. METHOD: Using chemotaxonomical methods to discuss the distribution characteristics of chemical constituents in Caprifoliaceae family. RESULTS: Iridoids and flavonoids were confirmed as the characteristic constituents of Caprifoliaceae family. CONCLUSION: Though there are great deviations among the genera of Caprifoliaceae family, it is not recommended to separate genus Sambucus and genus Viburnum from Caprifoliaceae family.

Caprifoliaceae↗

PubMed1999

Monitoring of cardiac troponin I in patients with acute heart failure.

Cardiac troponin I (cTnI) and creatine kinase MB isoenzyme (CK-MB) were measured in the plasma of 37 patients with acute heart failure. Elevated plasma cTnI concentrations were found in 89% of acute heart failure patients (P < 0.001 compared with a normal population), while plasma CK-MB showed no significant difference (P = 0.09). During follow-up, serial measurements of cTnI and CK-MB were performed. In acute heart failure patients, improvement of the clinical profile was associated with declining cTnI concentrations, while deterioration of heart function was closely related to increasing cTnI. Plasma CK-MB activities remained within the normal range throughout the observation period. This preliminary study provides evidence of cardiac damage to functionally overloaded myocytes. cTnI may be a sensitive marker both for early detection of myocyte damage and for monitoring of function in patients with acute heart failure.

Aged↗

PubMed1999

Monitoring human chorionic gonadotrophin level: evaluation of urine as an alternative specimen type.

Although urine has been used widely for the qualitative detection of human chorionic gonadotrophin (hCG), serum is chosen conventionally for the serial quantification of the hormone to monitor trophoblastic activity. In response to requests from both clinicians and patients regarding the use of urine as an alternative specimen type, we designed this comparative study to evaluate the possibility, taking into account both laboratory technique and the distribution of hCG within different body fluids. Using the Access Chemiluminescent Immunoassay System, total beta-hCG was measured in serum and urine (n = 30) collected from patients hospitalised for first-trimester abnormal pregnancy. Results obtained with normalised urine (corrected with urinary creatinine) and serum total beta-hCG correlated well (r = 0.98, P < 0.001), and we concluded that urine could be used as an alternative specimen type for the serial quantitation of hCG to monitor trophoblastic activity. However, the assay used must detect the common beta 2 epitope.

Biomarkers↗