Distribution of apolipoprotein E genotypes in fragile X syndrome and Batten disease.
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Adolescent↗
Biomedical subjects
N Zhong
Publications and source records attributed to N Zhong.
Prenatal fragile X detection using cytoplasmic and nuclear-specific monoclonal antibodies.
We have been carrying out studies aimed at improving prenatal detection of the fragile X chromosome/mutation. Our current protocol requires a turnaround time (TAT) of several days. In an attempt to reduce the TAT, we have turned to the use of monoclonal antibodies (mAbs). Monoclonal antibody 1A1 (provided by Dr. Mandel of INSERM) immunostaining was performed according to a modified three-step immunocytochemical procedure. We found that cytoplasmic staining intensities, using mAb 1A1/avidin biotinylated complex/diaminobenzidine, varied from light to heavy within each sample, with controls exhibiting a majority of heavily stained cells in both chorionic villus (CV) sample and amniotic fluid cultured cells. Using mAb 1A1 and a new nuclear-specific antibody, mAb 3F11, we found that CV cultured cells harboring the FMR1 full mutation could be distinguished from controls as early as 10 weeks of gestation in both male and female specimens. Western blot analysis showed that the antibodies have similar staining patterns but that mAb 3F11 has fewer background/nonspecific bands. Our results demonstrate that it is feasible to detect fragile X full mutations within one day after obtaining cells from CV specimens taken as early as 10 weeks of gestation.
Amino Acid Sequence↗
Accelerated prenatal diagnosis of fragile X syndrome by polymerase chain reaction restriction fragment detection.
Prenatal diagnosis of fragile X syndrome requires detection of the full FMR1 mutation in chorionic villus or amniotic fluid cell samples. Although analysis of genomic DNA restriction fragment pattern is a highly reliable technique for identification of the full FMR1 mutation, standard Southern blot determination of this pattern requires significantly more genomic DNA than is initially available from a prenatal sample. To overcome this limitation we developed a method that determines the diagnostic pattern of genomic restriction fragments from a fraction of a prenatal specimen. The prenatal DNA sample is first digested with EcoRI and EagI, and after agarose gel electrophoresis, the 2- to 10-kb region of the gel is serially sectioned and amplified by polymerase chain reaction. Analysis of prenatal samples from an unaffected male and from a full mutation male showed that this approach generated a diagnostic pattern comparable with a Southern blot of 100-fold more material. This innovation enables laboratories to prenatally diagnose the full FMR1 mutation sooner than standard techniques.
Blotting, Southern↗
Reevaluation of neuronal ceroid lipofuscinoses: atypical juvenile onset may be the result of CLN2 mutations.
This study describes the phenotype/genotype analyses of 56 probands with a juvenile onset, some of which had atypical features of neuronal ceroid lipofuscinosis, collected at the New York State Institute for Basic Research (IBR). In this group, we found probands with abundant curvilinear profiles in lysosomal storage material, deficiency of pepstatin-insensitive peptidase, and mutations in the CLN2 gene, as well as patients with a predominance of granular osmiophilic deposits in the lysosomal storage material, deficiency of palmitoyl-protein thioesterase, and mutations in the CLN1 gene. We have divided the probands into two categories: typical (or classic) and atypical. Most of the typical and atypical probands had onset of symptoms about or after 4 years of age. Interfamiliar and intrafamiliar variations were found, especially in the speed of becoming practically blind. Thus, our study indicates that some mutations in the CLN1, CLN2, and CLN3 genes may be associated with late onset of the disease process, may have a more benign clinical course, and clinic overlap with other forms of neuronal ceroid lipofuscinosis.
Adolescent↗
Late infantile neuronal ceroid lipofuscinosis is due to splicing mutations in the CLN2 gene.
Late infantile neuronal ceroid lipofuscinosis, LINCL, is one of the most common pediatric neurodegenerative disorders. It is caused by mutations in the CLN2 gene, which encodes a lysosomal pepstatin-insensitive peptidase (LPIP). We have identified a novel mutation, T523-1G --> A, by molecular analyses of three unrelated LINCL cases. The mutation was found to affect a 3' intronic splicing acceptor site, resulting in an aberrant mRNA with an insertion of 146 bp of intronic sequence. This causes a frame shift, produces a nonfunctional truncated protein, and results in LINCL.
Adenine↗
5-HTTLPR variants not associated with autistic spectrum disorders.
To determine whether there is an association of polymorphic variants of the serotonin transporter (5-HTT) gene-linked polymorphic region (5-HTTLPR) and autistic spectrum disorders, we analyzed the 5-HTTLPR genotypes of 72 autistic subjects, 11 fragile X syndrome patients with autistic behavior, 43 normal subjects, and 49 fragile X syndrome non-autistic subjects. The distribution frequency of 5-HTTLPR long allele (L) and the short allele (S) variants showed no differences between subjects. Our findings do not support the hypothesis that polymorphic 5-HTTLPR variants are a susceptibility factor for autistic disorders.
Alleles↗
Comparison of the capacity of beta-cyclodextrin derivatives and cyclophanes to shuttle cholesterol between cells and serum lipoproteins.
Previous studies from this laboratory have demonstrated that low concentrations of cyclodextrins (<1.0 mm), when added to serum, act catalytically as cholesterol shuttles to accelerate the exchange of free cholesterol between cells and serum lipoproteins. As cholesterol shuttles, cyclodextrins have the potential to serve as pharmacological agents for modifying cholesterol metabolism. In the present study, we have quantitated the cholesterol-shuttling capacity of a series of newly synthesized beta-cyclodextrin derivatives (betaCDs), with varying structure, and two double-decker cyclophanes. The general protocol is as follows. [(3)H]cholesterol-labeled CHOK1 cells are incubated for 2 h with the test compounds alone or together with 5% human serum, and efflux of the cellular [(3)H]cholesterol is measured. As methyl beta-cyclodextrin (MbetaCD) served as the basis for comparison, initial experiments were conducted that demonstrated there was a dose-dependent stimulation of cell cholesterol efflux as the concentration of MbetaCD increased, with an EC(50) that was calculated to be 0.05 mm. To determine the cholesterol-shuttling capacity of the newly synthesized compounds, cell cholesterol efflux is measured when the compounds are present alone, at a concentration of 0.05 mm, or together with 5% human serum. Our results demonstrate that the double-decker cyclophanes are the most efficient cholesterol shuttles. Under our experimental conditions, methyl beta-cyclodextrin (MbetaCD) approximately doubles the efflux of cell cholesterol to serum, whereas one of the double-decker cyclophanes produces a 4-fold stimulation in efflux. Four of the beta-cyclodextrin derivatives (betaCDs) display shuttling ability similar to that of MbetaCD. Furthermore, there does not appear to be a structural pattern among the other betaCDs which could explain their shuttling capacity.
Animals↗
Modulation by muscarinic receptor antagonists on negative chronotropic effects of tetrandrine.
AIM: To investigate the influence of selective antagonist for muscarinic (M) receptor subtype on tetrandrine (Tet) reducing heart rate, inhibiting sinoatrial node (SAN) function, and its ionic mechanism. METHODS: Effects of reducing heart rate of Tet were maintained in isolated right atrium and pithed rats. Modification on action potentials (AP) of SAN cells and L-type calcium current (ICa-L) by Tet were recorded by means of standard microelectrode and patch-clamp whole cell recording techniques. RESULTS: Tet inhibited spontaneous beating rate of isolated right atrium (EC50, 23.7 mumol.L-1) and reduced heart rates in pithed rats in a concentration-dependent manner (EC50, 18.6 mg.kg-1). Automaticity of SAN was inhibited by Tet. AP upstroke velocity (Vmax), spontaneous depolarization rates in phase 4 (SP4) were decreased and sinus cycle length (SCL) was prolonged when treated with Tet. Tet (30 mumol.L-1) caused a reduction in peak value of ICa-L from (1275 +/- 190) pA to (498 +/- 94) pA in isolated single cardiomyocyte. Atropine and AF-DX 116 (M2 subtype selective antagonist) could attenuate such effects of Tet in a competitive mode. CONCLUSION: Negative chronotropic effects of Tet are due to its inhibition of ICa-L. Modification on ICa-L is the major mechanism of M receptor modulating Tet effects.
Action Potentials↗
[Effect of antisense oligonucleotides on endothelin converting enzyme expression and endothlin-1 release from airway smooth muscle cells].
OBJECTIVE: To explore the mechanism of TNF-alpha induced ET-1 release and evaluate the effects of endothelin converting enzyme (ECE) antisense oligonucleotides (oDNS) on TNF-alpha induced ET-1 release from airway smooth muscle cells (ASMC). METHODS: ASMC transfected with the antisense oligonucleodides of ECE vectored with lipofectin were established. TNF-alpha induced ECE-mRNA expression and ET-1 release from above cultured cells were determined by RT-PCR and ELISA. RESULTS: ET-1 levels (10.1 +/- 0.3) ng/L and ECE expression (ECE/beta-actin: 0.228 +/- 0.015) in cultured ASMC incubated with 1,000 U/ml TNF-alpha were significantly higher than those in controls without TNF-alpha incubation (7.3 +/- 0.8) ng/L, (0.132 +/- 0.032, all P < 0.01). However, after transfecting antisence ECE-oDNS in those cells, ET-1 levels and ECE expressions were significantly lower than those in control cells without antisense transfection. The inhibition rates were (29 +/- 5)% and (35 +/- 12)% respectively. CONCLUSIONS: Abnormal expression of ECE mRNA may be a keypoint responsible for TNF-alpha induced ET-1 release in human ASMC; TNF-alpha induced ET-1 release and ECE mRNA expression from human ASMC are inhibited by antisense oligonucleotide of ECE.
Aspartic Acid Endopeptidases↗
[Analysis of measured results of transient-evoked otoacoustic emissions].
OBJECTIVE: In order to provide grounds for clinical diagnosis, the normal sensitive parameters of the transient evoked otoacoustic emissions (TEOAE) in normal ears were studied. METHOD: 60 ears with normal hearing subjects using ILO-88 otodynamic analyzer system were measured, the click stimuli level is 80 dB SPL and the stimuli pattern used non-linear model. RESULT: Analysis of the normal values of the stability, A-B difference, response amplitude, wave reproducibility, band reproducibility and band SNR, dominant frequencies were obtained. CONCLUSION: The findings from comprehensive analysis of spectrum, response amplitude and reproducibility can be used as main sensitive parameters to evaluated whether or not of normal-hearing.
Acoustic Stimulation↗
[Effect of ear-canal air pressure variation on tempanometry using a sweep-frequency probe tone].
OBJECTIVE: By observing the effect of ear-canal pressure variation (ECPV) on tempanometry using a sweep-frequency probe tone, the roles of sweep-frequency tempanograms changes were studied. METHOD: Tympanograms using a sweep-frequence probe tone were measured for 60 ears of 30 subjects at ECPV by admittance (Y), susceptance (B), conductance (G) with GSI33 middle ear analyzer. RESULT: There was not obviously difference about phase angle and resonance frequency among 3 measured conditions (P > 0.05); Resonance frequency became higher with higher positive pressure and lower with lower negative pressure in ear-canal; delta Y, delta G got lower with higher positive and lower negative pressure at resonance frequency; delta B is about 0 mmhos and almost didn't change with ECPV; phase angle decreased with higher positive or lower negative pressure. delta Y, delta G and delta phi were the highest at the peak pressure. CONCLUSION: The higher the ear-canal positive pressure or the lower the negative pressure is, the higher the compliance and the lower the mass of middle ear is comparatively. The rub of middle ear is the lowest at normal peak pressure.
Acoustic Impedance Tests↗
[Diagnostic significance of transiently evoked otoacoustic emissions in meniere's disease].
OBJECTIVE: To judge the diagnostic significance of TEOAE by glycerol test in Meniere's disease. METHOD: TEOAE were recorded from all testing ears with or without Meniere's disease. RESULT: The wave reproducibility, amplitude of response, band reproducibility, band SNR in ears of affected ears with meniere's disease after administration of glycerol were increased, about which the parameters of affected ears in positive glycerol test were obviously higher than that in negative glycerol test. All parameters in normal ears with Meniere's disease increased too, and there have the changes of main frequency. CONCLUSION: TEOAE records of glycol test may be more sensitive and more simple than pure tone audiometry in diagnosing meniere's disease, and should be used more extensively.
Audiometry, Pure-Tone↗
[Characteristics of outward potassium currents of outer hair cell isolated from the guinea pig cochlea].
OBJECTIVE: To study the normal values and characteristics of potassium currents (Ik) of outer hair cell (OHC) isolated from the guinea pig cochlea. METHOD: With the patch-clamp whole cell recording technique and several supplementary methods, the Ik potassium tail current (Iktail) and reverse potential were recorded under the conditions of the various intra and extracellular solutions and various command voltage stimuli. RESULT: Ik possessed evident voltage and time-dependence. The peak current appeared within 20 ms. The average activated potential was approximately -32.7 mV. Ik increased fastestly and greatestly in the voltage range from the activating voltage to 0 mV, and it approached saturation approximately at 40 mV. In normal status, no distinct "rundown phenomenon" of Ik appeared. When 10 mmol/L KCl was put in extracellular solution, Ik would increased. Nevertheless, when K+ was substituted by Cs+ in the intracellular solution, Ik would disappear. The reversal potential, -64.0 mV in average approximately, could be measured by means of Iktail. Furthermore, by means of slope command voltage stimuli, the processes of Ik activation, increment or decrement and saturation could be observed. CONCLUSION: As showing by the above described features, Ik possessed the characteristics of both an inward rectifier and rapid element of a delay rectifier, which would play important role in frequency tuning, mechanic-electrical transduction, maintenance of resting potential and excitement in OHC.
Animals↗
[The influence of short-term pure tone exposure on amplitude of distortion-product otoacoustic emissions and spectral history].
OBJECTIVE: To observe the changs of the amplitude and the spectral history of DPOAE in the slightly damaged cochlea. METHOD: Fifteen of young person with normal hearing were exposed to 4 kHz short-term pure tone (Level = 130 dB SPL) for 3 minutes to analysis the change of DPOAE in details after Temporary Threshold Shift (TTS). RESULT: The comparison of pre- and postexposure showed that the thresholds of sound reflex is 9.78 +/- 6.98, 8.04 +/- 5.58, 13.0 +/- 5.58 dB HL and 8.82 +/- 6.23, 5.75 +/- 4.42, 9.05 +/- 2.27 dB HL in 0.5, 1, 2 kHz, respectively. The amplitude of DPOAE decreased 4.28 dB SPL in 6 kHz, and the spectral history rippled significantly. The coefficience of variance is 5.18 +/- 1.63%. The combination of the amplitude and the coefficience of variance indicated that 80.0% of those is abnormal. CONCLUSION: The results confirmed that the spectral history of DPOAE is a sensible tool to assess the slightly cochlear lesion together with the amplitude of DPOAE.
Adolescent↗
[TCD functional test for vertigo induced by ischemic cerebrovascular disorders].
OBJECTIVE: To diagnose differentially the vetigo induced by some ischemic cerebrovascular disorder. METHOD: Patients with vertebrobasilar artery transient ischemic vertigo (group A), migraine (group B), hyperventilation syndrome (group C), hypertension (group D) are measured by using TCD functional examination which included blood peak velocity of systolic (Vs) and diastolic (Vd) end-period of vertibrobasilar artery of routine TCD (TCD-R), one minute hyperventilation TCD (TCD-HV) and one minute voluntary apnea TCD (TCD-B) respectively. RESULT: It showed that the Vs, Vd are decreased under the three conditions in A, B and D groups. The most apparent decrease are obversed in D group. The values of the decrease are similar between group A and B. No changes are found in C group. The abnormal Vs incidences of TCD-B measurement in group A are higher than those in group B and C, but significant lower than those in group D; and in TCD-HV test lower than group D and C, higher than group B; in TCD-R test, lower than group D, and no difference with group B and C. The abnormal incidences of Vd in group A are lower than group D and higher than group B in TCD-B test. In TCD-HV test, the group A abnormol incidences are lower than group D but higher than group B and C. In TCD-R test, the abnormal incidences are lower than group D and no difference between group B and C. CONCLUSION: The TCD measuremen is useful for differential diagnosis of vertigo induced by ischemic cerebrovascular disorders.
Brain Ischemia↗
[Clinical value of distortion product otoacoustic emission (DPOAE) and their contralateral suppression effects].
OBJECTIVE: The present paper aimed at examining the role of DPOAE and their contralateral suppressive effects in evaluation medial olivocochlear system (MOCS) function status in human. METHOD: Seventeen subjects (34 ears) with normal hearing, 13 ears with cochlear hearing loss and 9 ears with retrocochlear hearing loss were studied on their DPOAE and contralateral suppression. RESULT: The results revealed that DPOAE amplitude significantly reduced in ears with cochlear hearing loss, contralateral suppression was smaller than normal ears but there was no significant difference between two groups. By contrast, DPOAE amplitude was much higher in ears with retrocochlear hearing loss than that in the other two groups. Contralateral suppression was significantly reduced or disappeared, and contralateral acoustic stimulus (CAS) even increased DPOAE amplitude in ears with retrocochlear hearing loss. CONCLUSION: DPOAE and suppression induced by CAS can be used as an index of medial olivocochlear system (MOCS) function in patients with sensori-neuaral hearing loss, and can differentiate cochlear hearing loss from retrocochlear hearing loss. The tests of DPOAE and contralateral suppression may have much more advantages in clinical application over any other audiological test.
Acoustic Stimulation↗
[Effects of sodium salicylate on outward potassium current, resting potential and membrane electric capacitance of the outer hair cell isolated from guinea pig cochlea].
OBJECTIVES: To study effects of sodium salicylate on the outward potassium current (IK), resting potential (RP) and membrane electric capacitance (MEC) of outer hair cells isolated from guinea pig cochleas and the cytoelectrophysiological mechanisms of effects of sodium salicylate on functions of hair cells. METHODS: Using the patch-clamp whole cell recording technique, IK, RP and MEC were measured before and after the administration of sodium salicylate at concentration of 0.1 or 1.0 mmol/L. The effects of sodium salicylate on IK, RP and MEC were observed. RESULTS: The effects of sodium salicylate on IK had time- and dosage-effect relations, of which the former mean IK increasing and then decreasing after administration, the later meant that the effects of sodium salicylate being much more dominant during either increasing or decreasing IK in higher concentration than in lower concentration. The mean RP was approximately--60 mV and the mean MEC was approximately 39 pF. Sodium salicylate could decrease RP and MEC, which possessed a dosage-effect relation, that is, the effect was stronger in higher concentration than in lower concentration, and there was no clear evidence for time-effect relation. CONCLUSIONS: The sodium salicylate might affect the K+ conduction at the lateral membrane and internal and external distribution of K+ in the outer hair cell. Sodium salicylate might affect the excitability and mechanical activity of the outer hair cell by means of affecting IK, RP and MEC, which might be one of the cochlear mechanisms of the effects of sodium salicylate on the functions of hair cells.
Animals↗
[Modification of cochlear active micromechanism by auditory cortex].
OBJECTIVE: To investigate the modification of active micromechanism of outer hair cells by auditory cortex. METHODS: 1. Effects of selective attention on distortion product otoacoustic emissions (DPOAE) were analyzed in 9 human subjects with normal hearing. Visual tasks, two letters, O and Q, were alternatively displayed on a computer screen. Letter Q was target stimulus flashing randomly (probability was 20%), and letter O was non-target stimulus occurring regularly (probability was 80%). 2. In 13 guinea pigs, DPOAEs were measured before and after decerebration. RESULTS: 1. Visual tasks suppressed DPOAE significantly in both 1 kHz and 2 kHz (P < 0.05). 2. DPOAE reduced significantly in decerebrated guinea pigs. CONCLUSION: The study further demonstrates that the efferents from the auditory cortex do innervate the cochlea, and the efferent pathway passes from the auditory cortex, the super olive complex to the cochlea. Through this pathway the auditory cortex modulates the cochlear active micromechanism. The underlying mechanism was discussed.
Acoustic Impedance Tests↗