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Biomedical subjects

S X Hu

Publications and source records attributed to S X Hu.

71 records · Page 4Linked to original sources
PubMed1990

Increased glutamate uptake and glutamine synthetase activity in neuronal cell cultures surviving chronic hypoxia.

To examine the neurochemical effects of chronic hypoxia on immature nervous tissue in vitro, mixed neuronal-glial cell cultures derived from fetal mice were exposed to 5% O2 for 24 or 48 h. Those cultures subjected to longer hypoxia manifested improved neuronal survival compared to those with the shorter insult, both with respect to neuronal morphology and also cell counts. Neurochemical assays were performed on living cells in situ to determine the possible basis for differential cell survival. After both exposure conditions. Ro5-4864-displaceable benzodiazepine (BDZ) binding, reflecting nonneuronal BDZ binding sites, was either not reduced or was elevated. Although initially reduced, binding of the excitatory amino acid (EAA) glutamate was progressively increased after both insults and, within 2 days after return to normoxia, was increased relative to control values (121 and 128% of controls, P less than 0.05). The most impressive neurochemical differences between the two conditions related to changes in the predominantly or exclusively glial functions of glutamate uptake and glutamine synthetase activity. In those cultures with relatively preserved neuronal morphology: 1) high affinity uptake of glutamate was elevated compared to the shorter hypoxic insult by 3 days of recovery (104 vs 70%, P less than 0.001) and 2) glutamine synthetase, an enzyme localized primarily within astrocytes, was significantly elevated even when compared to absolute control values (148%, P less than 0.001). These data suggest that longer periods of hypoxia may be less deleterious to neurons than shorter hypoxic events because of a time-dependent stimulation of specific glial cell functions which relate to increased metabolism of potentially neurotoxic EAAs such as glutamate.

Alanine↗
PubMed1989

The retinoblastoma susceptibility gene product: a characteristic pattern in normal cells and abnormal expression in malignant cells.

Immunoprecipitation and Western immunoblotting studies were undertaken using purified high-affinity antibodies against a synthetic peptide corresponding to a portion of the deduced retinoblastoma (RB) protein. On SDS-PAGE, normal human cells showed an RB protein pattern consisting of a lower sharp band with a Mr of 110 kD and a more variable region above this band with a Mr ranging from 110 kD to 116 kD. The 110 kD band represents the unphosphorylated Rb protein whereas the broader, less well defined region is the phosphorylated RB protein in which molecular mass heterogenicity results from varying amount of phosphorylation. This pattern repeats once at a lower Mr in which a 98 kD band and 98-104 kD variable region can be visualized. This latter conformation seems to represent the unphosphorylated and phosphorylated RB protein translated from the second AUG codon of the RB mRNA. Cellular RB mRNA extracted from normal fibroblasts was translated in vitro reinforcing the usage of this second start codon. A higher ratio of phosphorylated to unphosphorylated Rb protein was seen in cells growing in log phase compared to those arrested in G1 phase. Our present studies also detected two candidates for RB-associated cellular proteins with a Mr of 124 kD and 55 kD respectively. In addition, shortened versions of RB-isoantigenic proteins were found in retinoblastoma and osteosarcoma cell lines.

Antibodies, Neoplasm↗
PubMed1989

Landau-Kleffner syndrome with unilateral EEG abnormalities--two cases from Beijing, China.

We reported 2 cases of Landau-Kleffner syndrome from Beijing whose clinical manifestations were very similar to ones previously reported. The onset of symptoms in these 2 cases was at 3 and 4 years of age, respectively, and both were characterised by unilateral focal epileptiform EEG discharges, without remarkable clinical seizures. One patient had normal SPECT study in addition to normal CT scan, BAER and VER results; the other had a family history of epilepsy. Since this syndrome may involve a primary brain disturbance responsible for both the epilepsy and aphasia without clear structural brain lesions, we wonder whether it can be classified as one of the benign functional partial epilepsies with genetic factors.

Aphasia↗
PubMed1989

Double-blind crossover controlled study on antiepilepsirine.

Antiepilepsirine (AES) is one of the derivatives of a Chinese folk prescription. It is a new antiepileptic drug (AED) synthesized in cooperation by Chinese medical and pharmaceutical workers. Pharmacological experiments on animal models prove that its antiepileptic action is marked, but there has been little evaluation of its clinical effects. We used the double-blind placebo-controlled crossover study which is generally acceptable as a proper method for new drug study. This study covered 58 epileptic children treated with classical AEDs and observed 6.5 months. Every patient took AES and placebo for 3 months each by random crossover on the basis of add-on therapy. The blood levels of AES and other antiepileptic drugs were determined regularly. The results show that there are no significant differences in clinical effects between AES and placebo in pediatric epilepsies as a whole, but AES is effective in tonic-clonic seizures (P less than 0.05), the most common type of seizure in the series. There are no significant differences in AED blood levels between the AES effective and ineffective groups. AES has no effect on the blood levels of other AEDs. AES is very safe, children given large doses (10 mg/kg/day) demonstrate no serious side-effects. It is suggested that there is potential improvement in patient psychological and cognitive status. This article also discusses the evaluation of new drugs for clinical effects, subject sampling, the criteria for efficacy evaluation and relationship between animal information and human outcome. The AES chemical structure is different from other well-known AEDs, this is a unique advantage.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

[Studies on the introduction and cultivation of Kaempferia galanga L].

This paper reports a systematic survey of the biological character istics of K. galanga. As a result of investigations on plant density, planting season, fertilization, storage of maternal tubers in winter and qualitative analysis of tubers, etc, cultural measures have been brought forth that suit the local climatic conditions and thus give high yield and quality of products.

Medicine, Chinese Traditional↗
PubMed1989

Cloning of apoprotein AI gene and observation on DNA polymorphism of apoprotein AI/CIII gene-loci in genomic library from a liver of Chinese.

For the research on the structure and function of the HDL apoproteins, we have successfully constructed a complete genomic library, in self-prepared EMBL3 lambda vector and the packaging extracts of lysogenic strains BHB2688, BHB2690, from a Chinese fetal liver, which will be widely used in the research on the structure and function of apoproteins. In this study, a DNA sequence polymorphism, revealed by digestion of human DNA with the restriction endonuclease Sst1 and hybridization with an apoprotein AI cDNA probe, has been shown to be located at apoAI/CIII gene-loci. Three gene related fragments (5.7 Kb, 4.0 Kb and 3.0 Kb) were detected. The 5.7 Kb fragment is common and the polymorphism is demonstrated by the presence of either a 4.0 Kb fragment (S1 allele) or the 3.0 Kb fragment (S2 allele). Individuals were genotyped S1S1 or S1S2. Our result showed that the frequency of genotype S1S2 was higher in hypertriglyceridemic subjects than that in normolipidemic subjects.

Apolipoprotein A-I↗
PubMed1986

Abnormal composition of apoproteins C-I, C-II, and C-III in plasma and very-low-density lipoproteins of non-insulin-dependent diabetic Chinese.

Apoprotein (apo) C-I, C-II, and C-III were measured in plasma from 35 white American non-diabetic subjects. The mean concentrations (mg/L) in plasma from normolipidemic and hypertriglyceridemic subjects, respectively, were apo C-I, 78 and 311; apo C-II, 37 and 200; and apo C-III, 98 and 529. These concentrations were strongly correlated with the concentrations of plasma triglyceride (TG). We also measured these apoproteins in 23 Chinese non-insulin-dependent diabetic patients (13 men, 10 women) and in eight male and 10 female non-diabetic Chinese controls. The male diabetics had significantly lower concentrations of apo C-I in plasma, and lower apo C-I/TG, apo C-II/TG, apo C-III/TG, and apo C-I/C-III ratios than did the controls. The female diabetics had significantly higher apo C-II concentrations than the controls. The median value for plasma glucose during fasting was 1400 mg/L in the male diabetic subjects, similar to the 1370 mg/L value in female diabetics. Therefore, the higher concentrations of very-low-density lipoprotein in male diabetics may not reflect hyperglycemia per se.

Adult↗
PubMedDate not supplied

Comparison of plasma lipoproteins and apoproteins in Chinese and American non-insulin-dependent diabetic subjects and controls.

Plasma lipoproteins and apoproteins were compared among Chinese and American controls and non-insulin-dependent diabetic (NIDDM) subjects in the same laboratory. Apoprotein AI concentrations in Chinese subjects, both NIDDM subjects and controls (men, 147 and 158 mg/dl, respectively), were significantly higher than those in American subjects (men, 104 and 124 mg/dl, respectively). Apoprotein AII concentrations, however, were comparable between Chinese and American subjects. Chinese NIDDM subjects had lower high-density lipoprotein cholesterol (HDLC), higher low-density lipoprotein cholesterol (LDLC), and higher apoprotein B levels than Chinese controls. Chinese subjects with NIDDM had HDLC and LDLC levels similar to those of American controls but trends of higher HDLC and lower LDLC compared with American subjects with NIDDM. These differences may in part explain the relatively higher incidence of atherosclerotic vascular disease in Americans.

Apolipoproteins↗
PubMedDate not supplied

Immortalization of fibroblasts from two patients with hereditary retinoblastoma.

Two RB fibroblastic strains from patients with hereditary retinoblastoma (RB), namely, RB80F/250R and RB110F, were transfected with plasmid DNAs encoding SV-40 large T-antigen at passage 31 and 10, respectively, These transfected fibroblasts developed into two immortalized cell lines. RB80F/250R/ori- and RB110F/gpt. RB110F/gpt had a similar doubling time as the parental cells, whereas RB80F/250R/ori- grew more rapidly with a doubling time of 19 hours compared to the parental cells which had a doubling time of 50 hours. The RB80F/250R/ori- cell line was particularly interesting cytogenetically since no normal chromosome 13 was present, although a marker chromosome 13 was found. In contrast, two apparently normal chromosome 13s were present in RB110F/gpt cells, but these cells had a marker chromosome which involved chromosome 14 (14 p+). Both the cell lines also had an abnormal chromosome 1 (1q-). RFLP analysis using the chromosome 13 specific VNTR probe, pTH162, assigned to 13q14.1 showed that the DNA from the RB80F/250R/ori- cells contained only a 6.1kb allelic fragment whereas the DNAs from parental RB80F/250R and RB80F cultures demonstrated both the polymorphic 8.0kb and 6.1kb allelic fragments. However, the RB gene per se was normal at the DNA level. Both cell lines expressed SV-40 large T-antigen together with elevated levels of p53 protein. In addition, levels of RB protein were the same in exponentially growing nontransformed parental cell strains and their immortalized cell lines. However, at confluency the levels of RB protein were greatly reduced in nontransformed cells but not in immortalized cell lines under similar conditions. In future studies using these immortalized cell lines, we shall make an attempt to discern the role of the RB gene and other tumor suppressor genes in the regulation of normal and malignant growth.

Cell Division↗