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Biomedical subjects

J Ran

Publications and source records attributed to J Ran.

9 recordsLinked to original sources
PubMed2001

[Estimation of insulin secretion rate in multiple sampled intravenous glucose tolerance test].

OBJECTIVE: To measure and calculate insulin secretion rate(ISR) in multiple sampled intravenous glucose tolerance test (FSIVGTT) according to the two compartment model and standard parameters of the kinetics of connecting peptide (C-P) in vivo. METHODS: 15 subjects with normal glucose tolerance and 11 type 2 diabetic patients took part in the study. Oral glucose tolerance test (OGTT) and FSIVGTT were performed. Glucose concentrations were measured by hexokinase method. Insulin (INS) and C-P concentrations were measured by radioimmunoassay. A computer procedure devised by our laboratory was used to calculate the value of ISR at each time point. RESULTS: In the control group, serum INS and C-P concentrations reached the peak at 4 min, the second peak was not obvious. In type 2 diabetes, only 5 subjects had a small peak within 4 min, two curves reached its peak between 60 and 80 min. In the control group, ISR reached its peak 2 min after injection of glucose, that was earlier than INS and C-P curves in time sequence (P = 0.000), the second obvious peak was shown at 22 min. In type 2 diabetes, an obvious but small peak of ISR was shown at 2 min and all the patients had this peak. CONCLUSIONS: It is necessary to take the process of metabolic clearance of INS and C-P into consideration, when blood concentration of INS and C-P were used as indexes to evaluate the secretion function of beta-cells. The ISR profile is more sensitive for investigation of the second phase of insulin secretion in the control group and the first phase in type 2 diabetes group.

Blood Glucose↗
PubMed2000

[Studies on properties of biofriction and wear for friction pairs of UHMWPE and Ti matrix-TiN-TiC gradient film materials].

In order to search the possible application of friction pairs of UHMWPE and Ti6Al4V-TiN-TiC etc. gradient materials to total hip joint replacements, we have prepared Ti6Al4V-TiN-TiC etc. gradient film materials by using N ion implant, d. c plasma CVD(PCVD). The properties of biological friction and wear for friction pairs of HUMWPE and Ti6Al4V-TiN-TiC etc. gradient film materials were investigated. The friction coefficient of friction paris and the wear loss of worn UHMWPE were measured; the surface morphology was observed by SEM. It has been shown that in human serum lubrication the wear loss of HUMWPE decreases with the increase in the surface hardness of its pairing ceramic film material. The pairing Ti6Al4V-TiN-TiC gradient film material possesses highest surface hardness, compared with other materials studied; UHMWPE wear loss in lowest. The wear mechanism of studied pairs has been analysed as well in the present paper.

Biocompatible Materials↗
PubMed2000

[Primary study on characteristics of insulin secretion rate, metabolic clearance rate and sensitivity in non-insulin-dependent diabetic subjects from multiplex diabetic pedigrees].

OBJECTIVE: To investigate the characteristics of insulin secretion rate (ISR), metabolic clearance rate (MCR-I) and sensitivity and to explore their relationship with obesity in non-insulin-dependent diabetic subjects from multiplex diabetic pedigrees (MDP). METHODS: Fifteen subjects with normal glucose tolerance and 11 non-insulin-dependent diabetic patients from MDP were included in the study. Frequently sampled intravenous glucose tolerance test (FSIVGTT) was performed. Glucose, insulin (INS) and connecting-peptide (C-P) concentrations were measured. A computer procedure devised by our laboratory was used to calculate the value of ISR at each time point, then MCR-I was acquired. Insulin sensitivity index (SI) was calculated according to minimal model technique about glucose in FSIVGTT. RESULTS: The ISR curve in control group was biphasic, while in non-insulin. In non-insulin-dependent diabetic group, areas under the curves of C-P (AUCC) and ISR level (AUCS) measured during 0 approximately 16 min were 7.9 nmol.min(-1).L(-1) +/- 2.8 nmol.min(-1).L(-1), and 6.1 nmol +/- 2.2 nmol, respectively, which were significantly lower than those in control group 17.7 nmol.min(-1).L(-1) +/- 4.92 nmol.min(-1).L(-1) and 12.3 nmol +/- 3.9 nmol (P < 0.01). The two parameters were slightly higher than those in control group 155 nmol.min(-1).L(-1) +/- 44 nmol.min(-1).L(-1) vs 101 nmol.min(-1).L(-1) +/- 30 nmol.min(-1).L(-1) and 76 nmol +/- 26 nmol vs 54 nmol +/- 20.0 nmol (P < 0.05)measured during 16 approximately 180 min. There was no significant difference, between the two groups about the amount of insulin secretion during 3 hours (82 nmol +/- 28nmol vs 68 nmol +/- 21 nmol, P = 0.2). In control group, there were significant positive correlation, between AUCS, waist-hip ratio (WHR), and body surface area, (BSA) and significant negative correlation between MCR-I, SI and WHR, BSA (P < 0.01), and also between MCR-I and SI. In non-insulin-dependent diabetic group, AUCS were significantly correlated with body mass index (BMI) (P < 0.01), and MCR-I had significant negative correlation with AUCC (P < 0.01). CONCLUSIONS: There are obvious impaired first phase insulin secretion after glucose challenge in non-insulin-dependent diabetic subjects from MDP. Decrease in endogenous MCR-I might be an important factor to hyperinsulinemia and insulin resistance. Increased insulin secretion, decreased MCR-I and insulin sensitivity can be observed in abdominal obese subjects of control group.

Blood Glucose↗
PubMed1999

[Modification of the surface of prosthetic valve material by LGDP for protection against microbial adhesion].

This study aimed at the surface modification of prosthetic valve materials by means of cold glow discharge plasma. Orthogonal design was adopted to select the optimal scheme by the experiments of the singular factor, such as output power, gas flow rate, treatment time etc. The PEG-200 was introducted to the surface. Grafting a layer of heparin onto the surface; coating a layer of PEG-like onto the surface first, and then the grafting heparin. Comparing the adhesive amounts of staphylococcus epidermidis (SE), the adhesive curves for Dacron, which was treated by the above methods; the last one is the best.

Bacterial Adhesion↗
PubMed1998

[Self-organization neural network based ultrasonic heart image segmentation].

Segmentation is one of the most difficult problems in multidimensional reconstruction of ultrasonic heart image. In the present paper, a segmentation method of ultrasonic heart image using the self-organization neural network has been studied. This is an unsupervised segmentation method, which can segment images through clustering automatically. The results show that the present method has significant benefits over the traditional K-means algorithm.

Algorithms↗
PubMed1997

[Materials for joint replacement and friction and wear].

Debilitating diseases such as osteo- and rheumatoid arthritis, trauma and bone cancer can be treated by using prostheses. The wear resistance of materials for joint replacement can affect the service-quality and service-life of prostheses. Materials for joint replacement and friction and wear were briefly reviewed in this paper.

Alloys↗
PubMed1995

[Megaloblastic changes in cervical epithelium associated with oral contraceptives and changes after treatment with folic acid].

OBJECTIVE: To study the influence of oral contraceptives on cervical epithelium, serum and red blood cell folate levels of users and to observe the changes after treatment with folic acid. METHODS: Morphology of cervical epithelium, serum folate and red blood cell folate levels were studied in 101 women who had used oral contraceptives for over 6 months and 33 intrauterine devices users served as controls, 29 women using oral contraceptives with cervical megaloblastic changes were treated with folic acid (5mg daily) for 3-4 weeks and followed up for observation on morphological changes of cervical epithelium. RESULTS: The mean nuclear diameter of cervical epithelial cells was larger in the oral contraceptive group than that in the control group (P < 0.001). Megaloblastic changes in cervical epithelium occurred in 29 women in the oral contraceptive group (28.7%). There was significant difference in the occurrence of cervical megaloblastic changes between the two groups (P < 0.01). The level of red blood cell folate was lower in the oral contraceptive group than that in the control group (P < 0.05). There was no difference in serum folate, hemoglobin and neutrophil nuclear index between the two groups (P > 0.05). The mean nuclear diameter of cervical epithelial cells decreased significantly (P < 0.001) and multinuclear and vacuolar changes disappeared after folic acid therapy in 26 women with megaloblastic changes. CONCLUSIONS: Oral contraceptives reduced folate storage in the body and resulted in megaloblastic changes in cervical epithelium. This condition was improved with folic acid therapy.

Adult↗