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Biomedical subjects

Zhu Li

Publications and source records attributed to Zhu Li.

67 records · Page 4Linked to original sources
PubMed2003

[Sex distribution of neural tube defects and their birth outcome in high- and low-prevalence areas of China].

OBJECTIVE: To describe and analyze epidemiological characteristics of babies with neural tube defects (NTD) by sex and birth outcome in a high-prevalence and a low-prevalence areas of China. METHODS: Birth defects surveillance data collected from 1992 through 1994, as a part of the Sino-American cooperative project on NTD prevention, were used to classify NTD as four categories, i.e., anencephaly, encephalocele, high-level and low-level spina bifida according to the sites of lesion (high vs. low level lesion were cervicothoracic and lumbosacral, respectively). Each category was sub-classified, according to single or compound defect, as isolated external defects (including those with NTD only) or multiple external defects (including those with NTD and another major external birth defects that is not the sequence of a defect such as cleft lip with or without cleft palate). The rates of anencephalus, encephalocele, high- and low-level spina bifida (SB) in males and females and their sex ratios were calculated, adjusted for urban and rural areas, season, category and birth outcome by sex and sites of lesions (high vs. low). RESULTS: Totally, 784 NTD cases were identified from 326 874 recorded births (including live births, stillbirths and fetal deaths with a gestation age of at least 20 weeks). The prevalence rates of anencephalus (1.30 per 1 000 female births) and high-level SB (3.99) in females were higher than those (0.66 and 1.66 per 1 000 male births) in males in the high-prevalence northern regions; with adjusted prevalence rates of females 1.8 - 2.1 times greater than those of males. In the low-prevalence southern regions, the prevalence of high- (0.32 per 1 000 female births) and low-level SB (0.21) in female were higher than those in males, with high- and low-level SB rate of 0.10 and 0.09 per 1 000 male births), with adjusted rates for females of 1.3 - 1.6 times higher than in males. Isolated NTD accounted for more than 80% of all NTD cases, and the prevalence of isolated NTD in females (2.57) was higher than that in males (1.40). CONCLUSIONS: The sex differences in NTD existed between north and south, in accordance with the phenotype of NTD. It suggested that proportion of high level SB and anencephalus in females could increase as the prevalence of NTD going up, anencephaly, high- and low-level SB had the different genetic and environmental background.

China↗
PubMed2003

[Premature, low birth weight, small for gestational age and childhood cerebral palsy].

OBJECTIVE: To investigate the relationship between perinatal risk factors such as premature, low birth weight, small for gestational age and childhood cerebral palsy (CP). METHODS: A cross sectional survey was carried out among 305,263 children aged 1 - 6 years old in seven cities of Jiangsu Province, China from May to July 1997. The perinatal risk factors were analysed. RESULTS: Four hundred and eighty-four cases of CP were found among this population. The prevalence of CP for children aged 1 - 6 years old was 1.59 per thousand. The prevalence of CP were strongly correlated to prematurity (RR = 25.16), low birth weight (RR = 19.63), and also highly correlated to small for gestational age (RR = 4.34). For smaller groups divided by small for gestational age (SGA), appropriate for gestational age (AGA), large for gestational age (LGA) and then by gestational age, prematurity was found to be at high risk in SGA (RR = 9.29), AGA (RR = 28.34) and LGA (RR = 21.41) groups. For groups divided by gestational age and then by SGA, AGA and LGA, SGA was found to have significantly high risk in premature (RR = 1.45), mature (RR = 4.41) and postmature (RR = 3.19) groups. Nine groups were divided by the gestational age along with SGA, AGA and LGA, rates of CP were found to be significantly higher in most groups than in the term AGA group. Compared with the rate of CP in the term AGA group, the RR were calculated and showed as followings (from higher to lower), premature SGA (RR = 40.99), premature AGA (RR = 28.34), premature LGA (RR = 21.08), postmature SGA (RR = 8.39), mature SGA (RR = 4.41) and postmature AGA (RR = 2.63). CONCLUSION: Prematurity and small for gestational age are both independent risk factors for cerebral palsy. Postmaturity and large for gestational age are not risk factors.

Cerebral Palsy↗
PubMed2002

Cholinergic modulation of basal and amphetamine-induced dopamine release in rat medial prefrontal cortex and nucleus accumbens.

Behavioral evidence suggests that muscarinic/cholinergic inhibition of brain dopaminergic activity may be a useful principle for developing novel antipsychotic drugs (APDs). Thus, oxotremorine, a muscarinic agonist, attenuates amphetamine-induced locomotor activity in rodents, an effect also produced by a wide variety of proven APDs, whereas scopolamine, a muscarinic antagonist, has the opposite effect. Since atypical APDs such as clozapine, olanzapine, risperidone, ziprasidone and quetiapine, increase brain acetylcholine as well as dopamine (DA) release in a region-specific manner, their effects on cholinergic and dopaminergic neurotransmission may also contribute to various actions of these drugs. Oxotremorine (0.5-1.5 mg/kg) dose-dependently and preferentially increased DA release in rat medial prefrontal cortex (mPFC), compared to the nucleus accumbens (NAC). However, S-(-)-scopolamine (0.5-1.5 mg/kg) produced similar increases in DA release in the mPFC, but the effect was much less than that of oxotremorine. Whereas a dose of S-(-)-scopolamine of 0.5 mg/kg comparably increased DA release in the mPFC and NAC, 1.5 mg/kg had no effect on DA release in the NAC. Oxotremorine-M (0.5 mg/kg), a M(1/4)-preferring agonist, also increased DA release in the mPFC, but not the NAC, an effect completely abolished by telenzepine (3 mg/kg), a M(1/4)-preferring antagonist, which by itself had no effect on DA release in either region. Oxotremorine (0.5, but not 1.5, mg/kg) attenuated amphetamine (1 mg/kg)-induced DA release in the NAC, whereas S-(-)-scopolamine did not. Oxotremorine (1.5 mg/kg) and S-(-)-scopolamine (0.5 mg/kg) modestly but significantly potentiated amphetamine (1 mg/kg)-induced DA release in the mPFC. These results suggest that stimulation of muscarinic receptors, in particular M(1/4), as indicated by the effect of oxotremorine-M and telenzepine, may preferentially increase cortical DA release and inhibit amphetamine-induced DA release in the NAC.

Acetylcholine↗
PubMed2002

Atypical antipsychotic drugs, quetiapine, iloperidone, and melperone, preferentially increase dopamine and acetylcholine release in rat medial prefrontal cortex: role of 5-HT1A receptor agonism.

Preferential increases in both cortical dopamine (DA) and acetylcholine (ACh) release have been proposed to distinguish the atypical antipsychotic drugs (APDs) clozapine, olanzapine, risperidone and ziprasidone from typical APDs such as haloperidol. Although only clozapine and ziprasidone are directly acting 5-HT(1A) agonists, WAY100635, a selective 5-HT(1A) antagonist, partially attenuates these atypical APD-induced increases in cortical DA release that may be due to combined 5-HT(2A) and D(2) blockade. However, WAY100635 does not attenuate clozapine-induced cortical ACh release. The present study determined whether quetiapine, iloperidone and melperone, 5-HT(2A)/D(2) antagonist atypical APDs, also increase cortical DA and ACh release, and whether these effects are related to 5-HT(1A) agonism. Quetiapine (30 mg/kg), iloperidone (1-10 mg/kg), and melperone (3-10 mg/kg) increased DA and ACh release in the medial prefrontal cortex (mPFC). Iloperidone (10 mg/kg) and melperone (10 mg/kg), but not quetiapine (30 mg/kg), produced an equivalent or a smaller increase in DA release in the nucleus accumbens (NAC), respectively, compared to the mPFC, whereas none of them increased ACh release in the NAC. WAY100635 (0.2 mg/kg), which alone did not affect DA or ACh release, partially attenuated quetiapine (30 mg/kg)-, iloperidone (10 mg/kg)- and melperone (10 mg/kg)-induced DA release in the mPFC. WAY100635 also partially attenuated quetiapine (30 mg/kg)-induced ACh release in the mPFC, but not that induced by iloperidone (10 mg/kg) or melperone (10 mg/kg). These results indicate that quetiapine, iloperidone and melperone preferentially increase DA release in the mPFC, compared to the NAC via a 5-HT(1A)-related mechanism. However, 5-HT(1A) agonism may be important only for quetiapine-induced ACh release.

Acetylcholine↗
PubMed2002

Multiecho segmented EPI with z-shimmed background gradient compensation (MESBAC) pulse sequence for fMRI.

A MultiEcho Segmented EPI with z-shimmed BAckground gradient Compensation (MESBAC) pulse sequence is proposed and validated for functional MRI (fMRI) study in regions suffering from severe susceptibility artifacts. This sequence provides an effective tradeoff between spatial and temporal resolution and reduces image distortion and signal dropout. The blood oxygenation level-dependent (BOLD)-weighted fMRI signal can be reliably obtained in the region of the orbitofrontal cortex (OFC). To overcome physiological motion artifacts during prolonged multisegment EPI acquisition, two sets of navigator echoes were acquired in both the readout and phase-encoding directions. Ghost artifacts generally produced by single-shot EPI acquisition were eliminated by separately placing the even and odd echoes in different k-space trajectories. Unlike most z-shim methods that focus on increasing temporal resolution for event-related functional brain mapping, the MESBAC sequence simultaneously addresses problems of image distortion and signal dropout while maintaining sufficient temporal resolution. The MESBAC sequence will be particularly useful for pharmacological and affective fMRI studies in brain regions such as the OFC, nucleus accumbens, amygdala, parahippocampus, etc.

Adult↗
PubMed2002

Transient relationships among BOLD, CBV, and CBF changes in rat brain as detected by functional MRI.

The transient relationship between arterial cerebral blood flow (CBF(A)) and total cerebral blood volume (CBV(T)) was determined in the rat brain. Five rats anesthetized with urethane (1.2 g/kg) were examined under graded hypercapnia conditions (7.5% and 10% CO(2) ventilation). The blood oxygenation level-dependent (BOLD) contrast was determined by a gradient-echo echo-planar imaging (GE-EPI) pulse sequence, and CBV(T) changes were determined after injection of a monocrystalline iron oxide nanocolloid (MION) contrast agent using an iron dose of 12 mg/kg. The relationship between CBV(T) and CBF(A) under transient conditions is similar to the power law under steady-state conditions. In addition, the transient relationship between CBV(T) and CBF(A) is region-specific. Voxels with > or =15% BOLD signal changes from hypercapnia (7.5% CO(2) ventilation) have a larger power index (alpha = 3.26), a larger maximum possible BOLD response (M = 0.85), and shorter T(*)(2) (32 ms) caused by deoxyhemoglobin, compared to voxels with <15% BOLD signal changes (alpha = 1.82, M = 0.16, and T(*)(2) = 169 ms). It is suggested that the biophysical model of the BOLD signal can be extended under the transient state, with a caution that alpha and M values are region-specific. To avoid overestimation of the cerebral metabolic rate of oxygen changes seen using fMRI, caution should be taken to not include voxels with large veins and a large BOLD signal.

Animals↗
PubMed2002

SR46349-B, a 5-HT(2A/2C) receptor antagonist, potentiates haloperidol-induced dopamine release in rat medial prefrontal cortex and nucleus accumbens.

The combination of M100907, a putative antipsychotic drug (APD) and serotonin (5-HT)(2A) antagonist, and the typical APD haloperidol, can enhance dopamine (DA) release in rat medial prefrontal cortex (mPFC), an effect which has been postulated to be of value to improve cognition and negative symptoms. The present study demonstrated that another putative APD and 5-HT(2A/2C) antagonist, SR46349-B (10 mg/kg, but not 1-3 mg/kg) alone, but not M100907 (0.1 and 3 mg/kg) alone, increased mPFC DA release, whereas neither drug alone affected nucleus accumbens (NAC) DA release. Neither SR46349-B nor M100907 alone affected nucleus accumbens (NAC) DA release. Neither SR46349-B nor M100907 alone affected nucleus accumbens (NAC) DA release. SR46349-B (3 mg/kg) potentiated haloperidol-induced DA release in both regions, whereas M100907 (0.1 mg/kg) potentiated haloperidol (0.1 mg/kg)-induced mPFC DA release and inhibited it in the NAC. WAY100635 (0.2 mg/kg), a 5-HT(1A) antagonist, abolished the effects of haloperidol plus M100907 as well as SR46349-B on DA release in the mPFC, but did not do so in the NAC. Thus, 5-HT(2A) and 5-HT(2A/2C) antagonism together with haloperidol-induced D(2) antagonism may potentiate mPFC DA release via 5-HT(1A) agonism, whereas the combined effects of these agents on NAC DA release is not dependent upon 5-HT(1A) receptor stimulation. Interestingly, similar to the effect of SR46349-B, high dose M100907 (3 mg/kg), which might have antagonist activity at 5-HT(2C) receptors, potentiated 1 mg/kg haloperidol-induced DA release in the mPFC and NAC. These results suggest that 5-HT(2A/2C) antagonism may be more advantageous than selective 5-HT(2A) antagonism as an adjunct to D(2) antagonists to improve cognition and negative symptoms in schizophrenia.

Analysis of Variance↗
PubMed2002

Alzheimer Disease: evaluation of a functional MR imaging index as a marker.

PURPOSE: To measure changes in functional synchrony in the hippocampus in patients with mild cognitive impairment (MCI) and Alzheimer disease (AD). MATERIALS AND METHODS: Three subject groups (nine cognitively healthy elderly control subjects, 10 patients with probable AD, and five subjects with MCI) underwent resting-state functional magnetic resonance (MR) imaging for measurement of functional synchrony in the hippocampus. Functional synchrony was defined and quantified as the mean of the cross-correlation coefficients of spontaneous low frequency (COSLOF) components between possible pairs of voxel time courses in a brain region, or the COSLOF index. The two-tailed Student t test was used to determine differences in the COSLOF index between the control group, the probable AD group, and the MCI group. An operating characteristic curve was calculated to graphically depict the tradeoff between sensitivity and specificity of the COSLOF index. RESULTS: Functional synchrony quantified with the COSLOF index was obtained in AD, MCI, and control subjects. COSLOF index values were significantly lower in AD patients than in control subjects (t = 4.32, P <.0012). For MCI subjects, COSLOF index values were significantly higher than those of AD patients (t = -2.4052, P <.047) but significantly lower than those of control subjects (t = 2.257, P <.043). The exponential-class curve significantly fits the relationship between the COSLOF index and the Mini-Mental Status Examination score (chi(2) = 20.4), indicating the rapid decrease in cognitive capacity below a threshold of the COSLOF index. CONCLUSION: Our results suggest that the COSLOF index could be used as a noninvasive quantitative marker for the preclinical stage of AD.

Aged↗
PubMed2002

Improved insulin sensitivity is associated with restricted intake of dietary glycoxidation products in the db/db mouse.

Advanced glycation end products (AGEs), known promoters of diabetic complications, form abundantly in heated foods and are ingested in bioreactive forms. To test whether dietary AGEs play a role in the progression of insulin resistance, C57/BL/KsJ db/db mice were randomly placed for 20 weeks on a diet with either a low AGE content (LAD) or a 3.4-fold higher content of AGE (high AGE diet [HAD]), including (epsilon)N-carboxymethyllysine (CML) and methylglyoxal (MG). LAD-fed mice showed lower fasting plasma insulin levels throughout the study (P = 0.01). Body weight was reduced by approximately 13% compared with HAD-fed mice (P = 0.04) despite equal food intake. LAD-fed mice exhibited significantly improved responses to both glucose (at 40 min, P = 0.003) and insulin (at 60 min, P = 0.007) tolerance tests, which correlated with a twofold higher glucose uptake by adipose tissue (P = 0.02). Compared with the severe hypertrophy and morphological disorganization of islets from HAD-fed mice, LAD-fed mice presented a better-preserved structure of the islets. LAD-fed mice demonstrated significantly increased plasma HDL concentrations (P < 0.0001). Consistent with these observations, LAD-fed mice exhibited twofold lower serum CML and MG concentrations compared with HAD-fed mice (P = 0.02). These results demonstrate that reduced AGE intake leads to lower levels of circulating AGE and to improved insulin sensitivity in db/db mice.

Adipose Tissue↗
PubMed2002

[Variation of plasma folate levels in adults between some areas and different seasons in China].

OBJECTIVE: To describe the distribution of plasma folate concentrations and prevalence of folate deficiency in adults aged 35 to 64 years in some areas and different seasons in China. METHODS: Study subjects were sampled from the representative rural and urban areas in the south and north of China aged 35 to 64 years totaling 2 545, and their plasma folate concentrations were determined and analyzed. RESULTS: Plasma concentrations of folate in the southern population were significantly higher (16.9 nmol/L) than those in the north (8.3 nmol/L), and the prevalence of folate deficiency in the south (5.8%) was significantly lower than that in the north (37.1%). Plasma folate concentration varied with season either in the south or north. Plasma concentrations of folate were lower during the summer and the fall (15.0 nmol/L) than those during the winter and the spring (18.8 nmol/L) in the south, but without significant changes in the prevalence of folate deficiency in different seasons. However, the plasma folate concentrations were significantly higher during the summer and the fall (9.7 nmol/L) than those during the winter and the spring (7.1 nmol/L) in the north. And the prevalence of folate deficiency in the north was significantly higher in winter and spring (48.0%) than that in summer and fall (26.2%). CONCLUSIONS: There existed significant difference in plasma folate concentrations in adults between varied geographic areas in China, which differed from their seasonal changes.

Adult↗
PubMed2002

[Progress in researches on neural tube defects related the genes].

Neural tube defects are common birth defects which are ascribed to the combination of genetic and environmental factors. The genetic factors include cell growth factors,transformation factors and key enzymic genes involved in folate metabolism. This paper reviews the genes as focus of current investigation and the relationship between the genetic polymorphism on the specific sites and neural tube defects based on animal model and population epidemiological study. It indicates that the multifactors play an important role in the etiology of neural tube defects.

English Abstract↗