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Biomedical subjects

L Z Huang

Publications and source records attributed to L Z Huang.

8 recordsLinked to original sources
PubMed2006

Chronic neonatal nicotine upregulates heteromeric nicotinic acetylcholine receptor binding without change in subunit mRNA expression.

Smoking during pregnancy chronically exposes the fetus to nicotine resulting in long-term behavioral and cognitive deficits. Nicotine binds to neuronal nicotinic acetylcholine receptors (nAChRs), pentameric ligand-gated ion channels widely expressed in the nervous system. Chronic nicotine upregulates high-affinity nAChRs in animals and smokers. Here we determined if chronic nicotine treatment during a developmental period corresponding to the human third trimester regulates nAChR expression. Rat pups were intubated orally three times per day with or without nicotine (6 mg/kg/day) from postnatal day 1 to 8. Subunit mRNA expression was assessed by in situ hybridization. Expression of heteromeric and homomeric nAChR receptor was evaluated by autoradiography using (125)I-epibatidine and (125)I-alphabungarotoxin, respectively. nAChR expression was analyzed in cortex, hippocampus, thalamus and medial habenula from autoradiograms using computer assisted image analysis. Nicotine induced significant upregulation of heteromeric but not homomeric nAChRs in hippocampus, cortex and thalamus without changes in subunit mRNA expression. No effect of chronic nicotine on receptor expression was detected in the medial habenula, suggesting that nicotine's effect was mainly on alpha4beta2-type heteromeric nAChRs. The nicotine-induced upregulation was reversed after nicotine withdrawal. Receptor blockade by DHbetaE, an antagonist for heteromeric alpha4/beta2 nAChRs, did not prevent upregulation but increased expression to a similar degree as nicotine. Combination of both drugs had a cumulative effect. Thus, although transient, intermittent nicotine exposure as seen in smoking mothers is sufficient to upregulate heteromeric nAChRs during a critical period of brain development and could contribute to the behavioral deficits found in children whose mother smoked.

Age Factors↗
PubMed2000

[Influence of cleftpalate on middle ear conduction and eustachian function].

OBJECTIVE: To explore the influence and its degree of cleftpalate on middle ear conduction and eustachian function. METHOD: 41 cleftpalate patients (82 ears) were performed with otopharyngeal examinations, form of the ostium pharyngeum tubae auditivae observations and acoustic impedance measurements. The results were compared with healthy persons of normal hearing. RESULT: In the cases with cleftpalate, tympanic membrane pathological change incidence was 89.0% (73/82), ostium pharyngeum tubae auditivae of cracked shape was 59.5% (25/42), abnormal tympanogram was 83.1% (64/77), the negative rate of stapedius muscle reflex was 84.4% (65/77). There are significant different in comparison with healthy persons. In synthetic analyses, the rate of secretory otitis media with varied degree in the cleftpalate cases was 74.0% (57/77). CONCLUSION: There was a high incidence of middle ear pathological change and secretory otitis media in the cleftpalate patients. This high incidence was due to susceptivity of the nasopharynx on the infection, weak strength of the dilator tubae eustachii and the deformed shape of the ostium pharyngeum tubae auditivae.

Acoustic Impedance Tests↗
PubMed1999

[Calcium and chronic diseases].

Calcium plays a role in physiological functions in our body. Many diseases are associated with physiological dysfunction caused by abnormal calcium homeostasis. In this review, we discussed the relationships between calcium and some common chronic diseases including cardiovascular diseases. Here we put emphasis on hypertension and atherosclerosis, tumor, osteoporosis and osseous hyperostosis. The most appropriate daily calcium intake and adverse effects of high-calcium diets are also mentioned in this article.

Animals↗
PubMed1992

Variables affecting electronic root canal measurement.

This study was conducted in two parts. In the first part, 20 single-rooted teeth that had been scheduled for extraction were investigated. The electronic root canal lengths were measured in vivo with a Dental Sono-Explorer type Y-III, and the actual canal lengths were measured after extraction of the teeth. The rate of agreement of the two measurements was 77.5% within a range of +/- 0.5 mm, while it was 100% at +/- 2.0 mm, which is acceptable clinically. In the second part, there were 19 simulated canals whose lengths and apical foramen sizes were known beforehand. Experiments revealed a negative correlation between the areas of the apical foramina and the difference between the electronic and the actual root canal lengths. This relationship was shown by the linear regression equation: ŷ = 0.6-1.6x. With the exception of the smallest areas of foramina, electronic root canal length measurements were less than the actual lengths.

Analysis of Variance↗
PubMed1991

[Synthesis of muscopyridine and its analogs].

Muscopyridine (1) is one of the odoriferous constituents of natural musk. 1 was prepared previously in very low yield in multisteps. We report here one-step preparation of muscopyridine and its analogs by the cross-coupling method. The cyclocoupling is effected by slow dropwise addition of a THF solution of di-Grignard reagent under nitrogen to a well stirred mixture of an equimolar quantity of a dichloropyridine in THF containing a catalytic amount of Ni (dppp)Cl2. The reaction mixture is stirred at 35-40 degrees C for up to 20 h. Analogs 2, 3 and 4 have also been prepared by this method. The structure of these products and intermediates are determined by UV, IR, MS, and 1HNMR spectral data.

Odorants↗