Newborn screening for congenital heart disease using echocardiography and follow-up at high altitude in China.

BACKGROUND: Pulse oximetry screening for critical congenital heart disease (CHD) is inapplicable to high altitude due to the variedly decreased arterial saturations and rare complex CHD. We examined the incidence and spectrum of CHD in newborns using echocardiography at high altitude and followed up their outcomes. METHODS: A total of 1337 babies were studied. Echocardiography was performed in 1002 asymptomatic newborns (3-5 days). In the same period, retrospectively studied 394 newborns (≤2 days) admitted to the NICU where echocardiograph was performed in 335. In both groups, follow-up was made at 1-3, 6 and 12-18 months. RESULTS: The incidence of CHD in asymptomatic newborns was 27.8%, consisting secundum atrial septal defect (ASD) [175 (62.7%)], patent ductus arteriosus (PDA) [61 (21.9%)], ventricular septal defect (VSD) [8 (2.9%)] and multiple defects [35 (12.6%)]. And 19.4% in NICU patients with similar spectrum, except for 2 with complex CHD who died before discharge. By 12-18 months of follow-up, 30% of CHD remained open. Thirteen patients developed mild to severe pulmonary arterial hypertension (PAH), and 2 of them died of heart failure. CONCLUSIONS: The incidence of CHD in newborns at high altitude is about 20 times higher than that at low altitude, consisting mostly of simple forms with left to right shunt, with rare complex CHD. By 12-18 months, the incidence of CHD is still about 10 times higher than that at low altitude. About 8% patients developed PAH or death. Follow-up must be reinforced in order to provide early intervention and prevent from PAH or death.

Anatomical and hemodynamic evaluations of the heart and pulmonary arterial pressure in healthy children residing at high altitude in China.

OBJECTIVES: Altitude-hypoxia induces pulmonary arterial hypertension and altered cardiac morphology and function, which is little known in healthy children at high altitude. We compared the cardiopulmonary measurements between the healthy children at 16 m and those at 3700 m in China and between the Hans and the Tibetans at 3700 m. METHODS: Echocardiography was assessed in 477 children (15 day-14 years) including 220 at 16 m and 257 at 3700 m. The dimensions and wall thickness of the left- and right-sided heart, systolic and diastolic functions including cardiac output index (CI) were measured using standard methods. Mean pulmonary arterial pressure (mPAP) was estimated by the Doppler waveforms in the main pulmonary artery. RESULTS: Compared to the 16 m-group, 3700 m-group had higher mPAP, increasing dilatation of the right heart, and slower decrease in right ventricular hypertrophy in 14 years (p < 0.05). The left heart morphology was not different (p > 0.20). Systolic and diastolic functions of both ventricles were significantly reduced, but CI was higher (p < 0.0001). There was no difference in any measurement between the Hans and the Tibetans (p > 0.05). CONCLUSIONS: Children living at high altitude in China have significantly higher mPAP, dilated right heart and slower regression of right ventricular hypertrophy in the first 14 years of life. Systolic and diastolic functions of both ventricles were reduced with a paradoxically higher CI. There was no significant difference in these features between the Hans and the Tibetans. These values provide references for the care of healthy children and the sick ones with cardiopulmonary diseases at high altitude.

Synthesis and properties of O-carboxymethyl chitosan/methoxy poly(ethylene glycol) graft copolymers.

O-carboxymethyl chitosan/methoxy poly(ethylene glycol) graft copolymers (OCMCS-g-MPEGs) with different degrees of substitution (DS) were synthesized by reductive N-alkylation of chitosan with poly(ethylene glycol) aldehyde. The properties of OCMCS-g-MPEGs, including the solubility, structure, hydrodynamic behaviors, isoelectric point (IEP) and interaction with water-soluble chitosan, were investigated. As a PEGylated polyampholyte, OCMCS-g-MPEGs can resolve in water over all pH range and the pH value at IEP (pH(IEP)) decreases when DS increases. The hydrodynamic behaviors of OCMCS-g-MPEGs in deionized H(2)O are markedly affected by DS and pH(IEP) in the experiment concentration range. The particle size of the complexes of OCMCS-g-MPEGs with water-soluble chitosan is strongly affected by the concentration of water-soluble chitosan and the pH value.

[Cross-sectional study of the relation between carboxypeptidase-H antibody and islet beta cell function in patients with latent autoimmune diabetes in adults].

OBJECTIVE: To explore the relation between carboxypeptidase-H antibody (CPH-Ab) and islet beta cell function in patients with latent autoimmune diabetes in adults (LADA) and to further confirm the diagnostic value of CPH-Ab for LADA. METHODS: Five hundred and forty-five patients who were initially diagnosed as Type 2 diabetes mellitus (T2DM) were tested with CPH-Ab and GAD-Ab by radioligand assay (RLA). T2DM patients, according to CPH-Ab and GAD-Ab status, were divided into CPH-Ab(+) group, GAD-Ab(+) group, and Ab(-) group to compare their islet beta cell function [represented by fasting C-peptide (FCP) and 2h postprandial C-peptide (2hCP)]. The relation between CPH-Ab and islet beta cell function in LADA was analyzed. RESULTS: The fasting C-peptide level in CPH-Ab(+) patients was between that of GAD-Ab(+) patients and that of Ab(-) patients (P<0.05), and the difference was still significant when the 3 groups were stratified with duration of disease (All P<0.05), but not with body mess index (all P>0.05). Corrected by concomitant variables including age, age at onset, duration of disease, and sex, the differences among the 3 groups were statistically significant (both P<0.001). Among the 3 groups FCP was lower than Ab(-) group in CPH-Ab(+) (P<0.05) and both FCP and PCP were lower than Ab(-) group in GAD-Ab(+) group (P<0.05 and P<0.01). The proportions of patients with insulin deficiency in CPH-Ab(+), GAD-Ab(+), and Ab(-) group were 27.6% (8/29), 48.1% (8/52) and 13.5% (54/400), respectively, which were significantly different among the 3 groups (P<0.001). GAD-Ab, BMI, and fasting blood glucose had effects on FCP and PCP in T2DM patients (All P<0.05), while CPH-Ab did not enter the equation in multivariable stepwise regressive analysis (P>0.05). CONCLUSION: The effect of CPH-Ab is less marked than that of GAD-Ab on islet beta-cell function in LADA patients. The value of CPH-Ab for the failure of islet beta-cell function in LADA should be determined prospectively.

[Comparitive [Comparative] study of the indexes of pulmonary arterial pressure of healthy children at different altitudes by Doppler echocardiography].

OBJECTIVE: Reduced oxygen availability at a high altitude is associated with increased pulmonary arterial pressure (PAP). With the altitude goes up the change of PAP in healthy children is still not clear. The difference of PAP in native Tibetan and Han children at a high altitude are also not clear. Many studies have shown that Doppler echocardiographic estimation of PAP correlates closely to the values obtained with the invasive measurement. Therefore the indexes of PAP in health children living at different altitudes were investigated and the indexes of PAP in Han and Tibetan children at the high altitude were compared by Doppler echocardiography. METHODS: A randomized survey was carried out on the indexes of PAP with Doppler echocardiography (HP-8500 and CAL-163 echocardiographic machine) by two doctors of Qinghai Provincial Women and Children Hospital from June 1998 to July 2002. The survey covering Jiuzhi Qinghai (at 3700 m above the sea level), Xining Qinghai (at 2260 m above the sea level) and Shanghai (at 16 m above the sea level) included a population of 1061 children aged 0 - 14 years. The population of 1061 composed of 218 Han children at Shanghai, 567 Han children at Xining Qinghai and 276 children at Jiuzhi, Qinghai including 118 migrated Han and 148 native Tibetan children. The physical, EKG and chest X-ray examination of each child were carried out to ensure all the subjects were healthy. A pulse oximeter was placed on each child's foot to provide measurements of arterial oxygen saturation (SO2) distal to the ductus arteriosus. The indexes of PAP included right ventricular systolic time interval (RSTI) and mean of pulmonary arterial pressure (mPAP) which was assessed by a multiple regression equation (mPAP=27.79 + 35.42 x PEP/AT-50.85 x AT/ETc). The AT/ETc was that AT/ET was divided by R-R. The RSTI included previous ejection period (PEP), ascending time (AT), ejection time (ET), PEP/AT and AT/ET. All subjects were divided into 7 age groups. The data of PAP indexes were compared among three different altitude groups and age groups. The data of PAP indexes were also compared in Han and Tibetan children living over 3700 m sea level in each age group. RESULTS: With the altitude increase the SO2 of the subjects obviously reduced and the indexes of PAP changed. The SO2 correlated closely with the PEP, AT, PEP/A, AT/ET and mPAP (r = 0.352, 0.144, -0.394, -0.166 and -0.363, respectively; P < 0.01). The AT and AT/ET in the groups of 2260 m and 3700 m were shorter than those in the group of 16 m (P = 0.03-0.000) in each age group. The PEP and PEP/AT in 3700 m group were longer than those in 2260 m and 16 m groups (P=0.006-0.000) in each age group. The mPAP in 3700 m group was higher than that in 2260 m and 16 m groups in each age group (mean [+/-SE] mmHg, 35.23 +/- 8.72 vs 17.99 +/- 8.78 and 15.86 +/- 8.96 aged 0 - 28 d, 32.06 +/- 13.38 vs 20.72 +/- 5.71 and 14.64 +/- 8.19 aged to 6 mo, 31.83 +/- 10.53 vs 20.89 +/- 10.12 and 14.69 +/- 5.89 aged to 1 yr, 27.58 +/- 13.55 vs 19.12 +/- 9.75 and 17.36 +/- 6.71 aged to 3 yr, 24.19 +/- 8.38 vs 19.64 +/- 9.36 and 16.43 +/- 4.68 aged to 6 yr, 23.90 +/- 11.35 vs 16.77 +/- 6.79 and 14.42 +/- 6.50 aged to 10 yr, 23.08 +/- 7.31 vs 18.53 +/- 7.25 and 15.45 +/- 6.12 aged to 14 yr, P=0.000). With the growth of the children the reduction of PAP was remarkable at 3700 m above sea level (F=5.638 P=0.000), the mPAP indexes of the first, second and third age groups were evidently higher than those of the other age groups. The SO2, RSTI and mPAP in the native Tibetan children were not different from those in the migrated Han children (P > 0.05) in each age group. CONCLUSION: The PAP of healthy children at the high altitude was different from that of healthy children at the low altitude. The PAP of the healthy children at 3700 m above sea level was remarkably increased. At 3700 m above sea level the PAP of newborns and infants increased much more compared with that of juvenile. The race may not significantly affect the PAP at the high altitude. The high altitude hypoxic environment might play a major role in the increase of PAP.

[Replacement of insulin by fasting C-peptide in modified homeostasis model assessment to evaluate insulin resistance and islet beta cell function].

OBJECTIVE: To investigate the possibility of using C-peptide to replace insulin in homeostasis model assessment (Homa) to evaluate insulin resistance and islet beta cell function. METHODS: Oral glucose tolerance test (OGTT) was performed in 21 normal subjects, whose venous blood was drawn before taking glucose and 30, 60, 120 minutes after taking glucose. Insulin and C-peptide were determined with radioimmune assay. Homa indices of insulin resistance and islet beta cell function were calculated. Multiple stepwise linear regression model of insulin resistance was measured using C-peptide x blood glucose as independent variables and Homa-IR was used as the dependent variable, while the model of islet beta cell function was determined using C-peptide/(fasting blood glucose - 3.5) as the independent variable and Homaislet as the dependent variable. RESULTS: The modified Homa formula were: Homa-IR (CP) = 1.5 + fasting blood glucose x fasting C-peptide/2800 (F = 5. 511, P = 0.029), Homa-islet (CP-Normal) = 0.27 x fasting C-peptide /(fasting blood glucose - 3.5) + 50, and Homa-islet (CP-DM) = 0.27 x fasting C-Peptide/(fasting blood glucose - 3.5) (F = 212.961, P = 0.000), respectively. The modified Homa-IR (CP) and Homa-IR, Homa-islet (CP) and Homa-islet were highly correlated (r =0.689 and r = 0.788; all P = 0.000). Using Homa and modified Homa formula to evaluate the insulin resistance and islet beta cell function both in the normal and diabetic subjects was similar. CONCLUSION: Fasting C-peptide can substitute insulin in Homa model to assess insulin resistance and islet beta cell function. The modified homeostasis model assessment may be applied in the diabetics using exogenous insulin.

[Clinical characteristics and classification of 2128 outpatients with diabetes].

OBJECTIVE: To determine the clinical characteristics of diabetic outpatients and their classification,and to provide some suggestions for diagnostics, education and follow-up of outpatients. METHODS: We analyzed the data of 2 128 outpatients recorded in the past year, and studied the clinical characteristics, distribution of types and relation between glutamate decarboxylase antibody (GADA) and age, sex and duration. RESULTS: Of all the patients, 918 (43.1%) were new-onset, and 1883 (88.6%) aged 40 or older. Altogether 782(36.7%) of the patients were done with GADA examination and 4.2% of them were GADA positive. Twelve patients were type 1 diabetes and 764 were type 2 diabetes, respectively with 33.3% and 3.8% GADA positive. The prevalence of GADA positive was 5.1% for men and 3.2% for women (P > 0.05). The frequencies of GADA positive in patients with different duration (1 year, 5 years, 10 years and more) were 4.4%, 4.8%, 1.7% and 4.9% (P >0.05) respectively. CONCLUSION: The new-onset population of the studied patients is dominated by 40-year olds or older. Type 2 diabetes is the main type in the diabetes spectrum. The frequency of GADA positive is irrelevant to sex and duration.