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Biomedical subjects

X Ming

Publications and source records attributed to X Ming.

13 recordsLinked to original sources
PubMed2006

Prenatal and birth complications in autism.

OBJECTIVES: Prenatal and birth history as potential sources of risk factors in relation to the onset of autism were examined. METHODS: A cohort of 164 families of autistic children referred to The Autism Center at New Jersey Medical School-UMDNJ, Newark, New Jersey, over a two-year period was studied. Intake prenatal and birth history information was obtained from each family and reviewed by a clinician. RESULTS: Prevalence rates in this cohort for vaginal bleeding, prolonged labor and prematurity were higher than comparable rates reported nationally and in New Jersey. Clustering of multiple prenatal risk factors was observed. This clustering was associated with the age of the mother, but uncorrelated with birth order. CONCLUSIONS: These findings support the general hypothesis that systemic problems at the prenatal stage may form a distinct dimension of risk associated with autism.

Adolescent↗
PubMed2005

Increased excretion of a lipid peroxidation biomarker in autism.

It is thought that autism could result from an interaction between genetic and environmental factors with oxidative stress as a potential mechanism linking the two. One genetic factor may be altered oxidative-reductive capacity. This study tested the hypothesis that children with autism have increased oxidative stress. We evaluated children with autism for the presence of two oxidative stress biomarkers. Urinary excretion of 8-hydroxy-2-deoxyguanosine (8-OHdG) and 8-isoprostane-F2alpha (8-iso-PGF2alpha) were determined in 33 children with autism and 29 healthy controls. 8-iso-PGF2alpha levels were significantly higher in children with autism. The isoprostane levels in autistic subjects were variable with a bimodal distribution. The majority of autistic subjects showed a moderate increase in isoprostane levels while a smaller group of autistic children showed dramatic increases in their isoprostane levels. There was a trend of an increase in 8-OHdG levels in children with autism but it did not reach statistical significance. There was no significant correlation between the levels of the biomarkers and vitamin intake, dietary supplements, medicine, medical disorders, or history of regression. These results suggest that the lipid peroxidation biomarker is increased in this cohort of autistic children, especially in the subgroup of autistic children.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2005

L-nucleosides containing modified nucleobases.

The synthesis of base modified L-nucleosides is described with pyrrolo[2,3-d]pyrimidines, pyrazolo[3,4-d]pyrimidines, benzimidazoles, and imidazo[1,2-a]-s-triazines as nucleobases. The conformation of the nucleosides is studied and the antiviral activity is evaluated.

Antiviral Agents↗
PubMed2002

Genetic transformation of two species of orchid by biolistic bombardment.

We report here the transformation of two species of orchid, Dendrobium phalaenopsis and D. nobile,by biolistic bombardment. Calli or protocorm-like bodies (PLBs) were used as target explants. Gold particles (1.0 microm) coated with plasmid DNA (pCAMBIA1301) encoding an intron-containing beta-glucuronidase gene (gus-int) and a hygromycin phosphotransferase (hpt) gene were introduced into the PLBs or calli using the Bio-Rad PDS-1000/He Biolistic Particle Delivery System. Calli and PLBs were then chopped up and pre-cultured in 1/2-strength MS medium supplemented with 0.4 M mannitol for a 1-h osmoticum treatment before bombardment. Immediately after bombardment, the calli and PLBs were transferred to 1/2-strength MS medium without mannitol for recovery. Putatively transformed plantlets were obtained by selection and regeneration on medium supplemented with 30 mg/l hygromycin. The highest efficiency of transformation was obtained when selection was conducted at 2 days post-bombardment. For D. phalaenopsis and D. nobile, respectively, about 12% and 2% of the bombarded calli or PLBs produced independent transgenic plants. Integration and expression of the transgenes were confirmed by Southern hybridization and Northern hybridization. No nontransformed plants were regenerated, indicating a tight selection scheme. However, separate incorporation of the gus gene and the hpt gene was observed, and in one transgenic line the gus gene was integrated into the genome of the transgenic plant, but not expressed.

Biolistics↗
PubMed2001

Proliferating oligodendrocytes are present in both active and chronic inactive multiple sclerosis plaques.

The proliferation marker Ki-67 labels cell nuclei in the G(1), S, M, and G(2) phases of the cell cycle. We used Ki-67 immunohistochemistry to quantify proliferating glial cells in brain tissue sections from twenty-four patients, comprised of multiple sclerosis, normal brains, and other neurological disease controls. Glial proliferation was greatly increased in MS lesions when compared with control brain white matter. Both actively demyelinating/early remyelinating plaques and chronic inactive plaques of long standing often displayed large numbers of glial cells in the proliferative cycle. The bulk of these proliferating cells were of oligodendroglial lineage in the MS plaques. Ki-67 positive macrophage/microglial lineage cells were largely restricted to acute lesions. The finding of increased numbers of proliferating oligodendroglia in most MS plaques, regardless of disease duration or activity state, indicates that the MS brain is capable of recruiting unexpectedly large numbers of new oligodendrocytes over long periods of time. The factors within the MS plaque microenvironment that provoke new oligodendrocyte generation and their subsequent loss still need to be identified.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed2001

Cavernous angioma of the brain stem simulating diffuse pontine glioma.

Brainstem vascular malformations can sometimes simulate other conditions such as multiple sclerosis and pontine glioma. We report a case of brainstem cavernous angioma for which clinical course and radiologic appearance were suggestive of a pontine glioma. The diagnosis was uncertain until the clinical and radiologic evolution made it clear that the patient had a cavernous angioma. We suggest that brainstem angioma be considered as a differential diagnosis for pontine glioma.

Adolescent↗
PubMed1999

Up-regulated p75NTR neurotrophin receptor on glial cells in MS plaques.

OBJECTIVE: To investigate the expression of the neurotrophin receptor p75NTR on glial cells within MS plaques. BACKGROUND: In recent studies on the pathogenesis of MS white matter plaques, we found large populations of inflammatory and resident glial cells, including oligodendrocytes undergoing cell death, and identified increased expression of Fas receptor and ligand death pathway signaling molecules on the same glial cell types. In another study, the p75NTR was shown to induce apoptotic death of maturing oligodendrocytes when exposed to NGF in vitro. METHODS: We used immunohistochemistry and in situ reverse-transcription PCR to detect p75NTR expression on inflammatory and resident glial cells in MS plaques and used TUNEL staining for fragmented DNA to detect cell death. RESULTS: Up-regulated p75NTR messenger RNA and protein were demonstrated in both oligodendrocytes and microglia/macrophages in MS plaques but not in control white matter. However, only a fraction of p75NTR expressing oligodendrocytes was also stained by TUNEL. CONCLUSIONS: Glial cell expression of p75NTR receptor is up-regulated during MS plaque formation. The exact role of this receptor in glial cell death and/or survival in MS remains to be elucidated.

Antigens↗
PubMed1998

Rice dwarf phytoreovirus segment S11 encodes a nucleic acid binding protein.

The function of rice dwarf virus segment 11 and the corresponding segments of other phytoreoviruses is not yet determined. The amino acid sequence of Pns11, encoded by segment 11, contains a putative zinc finger and five flanking basic regions at the C-terminus. The full-length Pns11 protein and three truncated derivatives, which lack the N-terminus, the zinc-finger or the C-terminal five basic regions were expressed in Escherichia coli and their nucleic acid binding properties were studied. Pns11 interacts with single- and double-stranded forms of DNA and RNA in a sequence-nonspecific manner. The truncated derivative which contains both the zinc-finger and the C-terminal basic regions has the same binding properties as the full-length Pns11. However, removal of either of these domains prevents binding activity. The binding activity of Pns11 was drastically reduced when the blots were treated with a high concentration of EDTA. Moreover, Pns11 extracted from infected rice also binds to single-stranded RNA. These data suggest that RDV Pns11 binding activity is structure-dependent and it may play an important role in virus replication and/or genome assortment.

Amino Acid Sequence↗
PubMed1998

Fixation-off and eyes closed catamenial generalized nonconvulsive status epilepticus with eyelid myoclonic jerks.

PURPOSE: Eyelid myoclonic jerks have been described in fixation-off-sensitive (FOS) epilepsy, but their relationship to nonconvulsive status epilepticus (NCSE) or to catamenial exacerbations is little reported. METHODS: We describe a woman of normal intelligence with catamenial periods of prolonged NCSE who exhibited various intra- and interseizure thresholds of polyspike suppression when her eyes were open, with particular visual inputs and with antiepileptic drug (AED) treatment. RESULTS: In one episode, on the first day of the woman's menstrual period, bursts of bilateral synchronous polyspike activity were briefly suppressed with visual fixation but were more lastingly suppressed after administration of lorazepam (LZP). During another period of NCSE, the SE was completely suppressed by visual fixation on objects and patterned checkerboard screens and by ocular convergence, was incompletely suppressed when her eyes were open in a dark room and when her eyes were open without visual fixation, but was not suppressed by mental activation alone. CONCLUSIONS: FOS polyspike bursts with eyelid myoclonic jerks may exhibit catamenial exacerbations, varying from completely suppressible with visual fixation to nonsuppressible during NCSE. These findings suggest an interplay between humoral factors, AEDs, and seizure threshold in this condition.

Adult↗
PubMed1998

[A preliminary report of the effect of levodopa and carbidopa for childhood amblyopia].

PURPOSE: To explore the short-term effect of levodopa and carbidopa in 36 children (4.5-14 years) with refractory amblyopia. METHODS: 36 cases of incurable childhood amblyopia treated with occlussion with visual acuity stably for 6 months were retreated by levodopa and carbidopa 1.5 mg/kg, 0.38 mg/kg respectively for 3 months. Visual acuity, fusional and stereoscopic function, retinal light sensitivity and scotomas were observed at 1 and 3 months after tablet taken. Medicine side effects were observed. RESULTS: At 3 months, the visual acuity of 88.89% eyes were improved(average 2.27 +/- 1.26 line), fusional and stereoscopic function were restored in 10 and 6 cases respectively. Retinal light sensitivity significantly increased, scotomas disappeared in 19 eyes and contracted in 6 eyes. The basic cure rate was 42.86% Less side effect were found. CONCLUSION: Average dose levels(1.5/0.38 mg/kg) of levodopa and carbidopa were an effective and secuity method to improve visual function of refractory childhood amblyopia.

Adolescent↗
PubMed1996

[Effect of dietary selenium and germanium on the precancerous lesion in rat glandular stomach induced by N-methyl-N'-nitro-N-nitrosoguanidine].

N-Methyl-N'-nitrosoguanidine (MNNG) was administered (100 mg/L) in drinking water in 100 Wistar rats for 24 weeks to induce the precancerous lesion in glandular stomach. 77 rats with the precancerous lesion in glandular stomach were divided into 3 groups randomly at the 25 thweek. Yeast selenium (Yse, 4 mg/L) and carboxyethyl germanium sesquioxide (Ge-132, 600 mg/L) in drinking water were administered respectively in the corresponding treatment groups: 100 ml/MNNG in drinking water was administered in the treatment group, and 100 ml/MNN in drinking water was administered in the treatment group and control group for another 5 weeks. The experiment ended at the end of the 37th week. The results showed that the incidence of glandular stomach cancer in the Yse group was significantly lower than that in the control group; the infiltrating depth of glandular stomach cancer in the Yse group and the Ge-132 group was remarkably shallower than that in the control group. These findings suggest that Yse and Ge-132 have some preventive effect on the precancerous lesion in rat glandular stomach induced by MNNG.

Animals↗
PubMed1985

Structure of a precursor to the yeast mitochondrial tRNAMetf. Implications for the function of the tRNA synthesis locus.

A transcript from the yeast mitochondrial tRNAMetf gene has been isolated from a petite deletion mutant, ND40. RNA sequence analysis demonstrates that it has a 5' unprocessed extension of 28 nucleotides, and capping experiments with guanylyltransferase reveal that the first nucleotide has a 5' di- or triphosphate. A comparison of the RNA sequence with the tRNAMetf gene sequence reported here shows that transcription initiation occurs at a sequence homologous to a nonanucleotide segment implicated as a promoter element of yeast mitochondrial DNA. The 3' end of this transcript is identical to the mature tRNAMetf and carries a CCA sequence. The transcript can be processed in vitro to yield a mature tRNAMetf and thus appears to be a bona fide tRNA precursor. This tRNA precursor accumulates in the absence of the mitochondrial tRNA synthesis locus whereas mature tRNAMetf can be made from the same gene in the presence of the locus. This data provides clear and convincing evidence that the synthesis locus codes for a 5' tRNA processing function.

Base Sequence↗