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Biomedical subjects

M F Li

Publications and source records attributed to M F Li.

At least 19 recordsLinked to original sources
PubMed2006

Moderate to severe obstructive sleep apnoea patients is associated with a higher incidence of visual field defect.

PURPOSE: To compare the visual fields (VFs) and optic nerve head changes between obstructive sleep apnoea (OSA) in normotensive patients and an age-matched non-OSA population. DESIGN: Case-control study. PARTICIPANTS: A total of 41 ethnic Chinese patients diagnosed with moderate to severe OSA referred from the Sleep Laboratory, ENT Department, Tuen Mun Hospital. A total of 35 age-matched non-OSA subjects recruited from the Ophthalmology Department, North District Hospital. METHODS: Comprehensive ophthalmological and systemic history, complete ophthalmological examination, including central-30 computerized perimetry for all studied patients. MAIN OUTCOME MEASURES: Polysomnographic data, VF indices, optic disc changes. RESULTS: In the OSA arm, VF indices were significantly subnormal and the incidence of suspicious glaucomatous disc changes was four times higher than that of the control arm. None of the studied patients suffered from any form of anterior segment complications. CONCLUSIONS: Moderate to severe OSA is associated with a higher incidence of VF defect and glaucomatous optic nerve changes.

Adult↗
PubMed2005

Spectral features of LO phonon sidebands in luminescence of free excitons in GaN.

In the paper a combined experimental and theoretical investigation of the longitudinal optical phonon sidebands (PSBs) in the luminescence of free excitons in GaN at moderately high temperatures was reported. The spectral features, including line broadening, shift, and asymmetry of the one- and two-phonon PSBs, were revealed both experimentally and theoretically. It is found that the linewidth of the one-phonon PSB is surprisingly always larger than that of the two-phonon PSB in the interested temperature range. Moreover, the thermal broadening rates of the one- and two-phonon PSBs are considerably different. We adopted the Segall-Mahan theory [B. Segall and G. D. Mahan, Phys. Rev. 171, 935 (1968)] to compute the PSB spectra of the free excitons in GaN. Only one adjustable parameter, the effective mass of the holes, was used in the calculations. For the one-phonon PSB, an excellent agreement between theory and experiment is achieved when an adequate effective mass of the holes was used.

Journal Article↗
PubMed2002

Use of electroneurography as a prognostic indicator of Bell's palsy in Chinese patients.

OBJECTIVE: To evaluate the use of electroneurography (ENOG) as a prognostic indicator in Bell's Palsy for Chinese patients in Hong Kong. STUDY DESIGN: Prospective study. SETTING: Tertiary referral outpatient center. PATIENTS: Sixty-three consecutive patients with a diagnosis of Bell's Palsy in Tuen Mun Hospital, Hong Kong, from January 1995 to January 1998. INTERVENTIONS: ENOG, protective eye care, and exercise of the facial muscles. MAIN OUTCOME MEASURES: ENOG was performed 5 to 14 days after the onset of facial palsy. The recovery of facial nerve function was documented by House and Brackmann grading. All the patients were followed up monthly until recovery or up to 6 months. RESULTS: Sixty-three patients were randomly divided into two groups of 32 and 31 patients. The first part of the study was to analyze the correlation between ENOG values and the chance of recovery in Group 1 patients (n = 32) by means of a logistic regression model. The result showed that patients with ENOG values less than 72.63% had a greater than 90% chance of recovery to House Grade II or better within 2 months (Wald = 6.19, p < 0.05). The second part of the study was to assess the capability of this ENOG value to accurately predict the prognosis of Bell's Palsy in Group 2 patients (n = 31) using Fisher's exact test (p < 0.0001). The sensitivity and specificity of ENOG in predicting a good prognosis (recovery to House Grade III or better after 2 months) in patients with Bell's Palsy were 82% and 100%, respectively. CONCLUSION: The ENOG value as a useful prognostic indicator in Chinese patients with Bell's Palsy in Hong Kong was confirmed.

Adolescent↗
PubMed2001

[Cloning of secondary lymphoid-tissue chemokine (SLC) and its expression in prokaryotic system].

The total RNA from lymphoid tissue in Chinese was extracted, and the gene encoding the mature peptide of secondary lymphoid-tissue chemokine (SLC) was cloned by RT-PCR. Nucleotide sequence analysis showed that there is only one nucleotide different from that reported, but it doesn't alter the amino acid encoded. The SLC cDNA was inserted into an expression vector pET-28a(+) under T7 promoter and constructed recombinant plasmid pET28a-SLC. pET28a-SLC was transformed to E. coli BL21(DE3) and the expression strain was gotten. After inducing with IPTG for 3-5 hours the bacterium were sonicated. After centrifuging the supernatant was analysed by SDS-PAGE. An obvious expression band about 18 kD can be seen. The expressed product was purified by Ni2+ affinity chromatography column, and the purity is up to 90 percent.

Chemokine CCL21↗
PubMed2000

[Epidemiological investigation on an outbreak of angiostrongyliasis cantonensis in Wenzhou].

OBJECTIVE: To find out the cause and transmission factors of an outbreak of eosinophilic meningoradiculitis in Wenzhou City during October to November in 1997. METHODS: In addition to a retrospective cohort study on 182 persons who had dined at a same restaurant of the city, etiological and immunoserological investigations were conducted. RESULTS: Among 105 cases who had eaten the undercooked Ampullaria gigas in that restaurant, 47 cases were infected, the incidence rate was 44.8%; whereas none of the persons who did not eat the under-cooked Ampullaria gigas in that restaurant got the infection, the difference between the two groups being significant(P < 0.001). The incidence rate of the cases who had eaten 4 and more pieces of the undercooked Ampullaria gigas was 86.2%(25/29), while that of those who had eaten less than 4 pieces was 28.9%(22/76), the difference between the two being very significant (chi 2 = 27.83, P < 0.001, RR = 2.98). The third stage larvae of the Angiostrongylus cantonensis were found out from Ampullaria gigas living in the same locality, and the adult worms of Angiostrongylus contonensis were found out from the rats living in the locality else. The positive rate of serum anti-Angiostrongylus cantonensis antibody in the patients was 84.0%. CONCLUSION: On the basis of the clinical, epidemiological, immunoserological and etiological investigations, an outbreak of the angiostrongyliasis cantonensis caused by eating undercooked Ampullaria gigas was confirmed.

Adolescent↗
PubMed1998

p53 inactivating mutations in Chinese nasopharyngeal carcinomas.

Previously a low frequency of p53 mutations was detected in nasopharyngeal carcinoma (NPC) using molecular techniques to screen for mutations, yet immunohistochemical staining revealed a high frequency of p53 aberrant proteins. These findings might be attributed to the occurrence of p53 mutations outside the common hot spots and/or the inactivation of the protein through interactions with cellular or viral proteins. Using a previously established simple and sensitive p53 yeast functional assay, we blindly screened 25 nasopharyngeal biopsies for p53 mutations from exons 4 to 11. p53 was mutated in 27.3% of NPC specimens and in 0% of the nasopharyngeal biopsies from patients with non-malignant diseases. Two p53 mutations were detected in exon 7 and two were detected in exon 8. Interestingly, the exon 8 mutations observed in NPC lie in codons which appear to be hot spots for mutations in other head and neck cancers.

Adolescent↗
PubMed1996

[Cell cycle and apoptosis].

The progression of cell cycle in embryonic cells from oceanic bionts to mammalians is initiated, promoted and terminated under the regulation of cell cycle gene products, named cyclins, and a p34 (cdc 2). Besides, oncogene (proto-oncogene) products such as p53 and pRB also directly regulate the progression of cell cycle. However, the p34 (cdc 2) which promotes the mitotic cell division also initiates the apoptosis of certain cells. Therefore, mutations of genes that regulate the normal progression of cell cycle would cause cells in the cell cycle undergoing either apoptosis or uncontrollable proliferation.

Animals↗
PubMed1995

Faeces feeding by adult Phormia regina (Diptera: Calliphoridae): impact on reproduction.

Fresh beef liver, sugar, and five different types of faeces were evaluated as supportive diets for egg development in the blowfly Phormia regina. Females on a sugar diet were unable to develop follicles beyond stage 3, whereas liver proved to be the best diet for complete egg maturation. Some faecal diets were unable to support egg maturation when fed upon for a short period of time; however, longer periods of feeding produced complete egg maturation. The necessity to feed for longer periods of time in order to produce eggs on most of these diets was attributed to their low protein content. Males, in a shorter period of time than females, obtained enough protein from faeces to activate the neuroendocrine system involved in mating.

Animals↗
PubMed1993

Cloning, sequencing and expression in E. coli of interferon-omega 1 gene.

Human interferon omega 1 (huIFN-omega 1) gene was isolated and cloned from chromosome DNA derived from a Chinese fetal liver via polymerase chain reaction (PCR). By determining its nucleotide sequence we proved that the 88th codon should be GGA, coding for Gly. After engineering the original IFN-omega 1 gene clone to a form that may be expressed as a nonfused protein, we also took the IFN-omega 1 gene under the control of the PRPL promoter with an expression vector pBV220 in E. coli. The antivirus activity of the recombinant IFN-omega 1 is about 6.5 x 10(7) units/L CULTURE (OD600 = 0.75). Since IFN-omega 1 not only has antivirus activity but also shows considerably high homology with animal trophoblast proteins which have been proved antiluteolysins as a maternal recognition signal for pregnancy, we believe that study on it will be practically and theoretically significant.

Amino Acid Sequence↗
PubMed1992

A novel variant of human interferon alpha 1 gene.

A 520-base pair human IFN-alpha gene was isolated by PCR method twice from chromosome DNA of a Chinese (Han Nationality) fetal liver. The nucleotide sequences were determined. These two separately amplified DNA fragments shared the completely identical nucleotide sequence but possessed C and G at positions 410 and 541, respectively, which differ from those of IFN-alpha 1 and IFN-alpha D previously described. Therefore the deduced amino acid sequence would have an Ala at position 114 and a Val at position 158. At all other sites it has the same amino acids as those in IFN-alpha 1 and IFN-alpha D. We recommend that IFN-alpha D gene, IFN-alpha I gene and IFN-alpha I/158V gene found in our laboratory, be named IFN-alpha 1a gene, IFN-alpha 1b gene and IFN-alpha 1c gene.

Amino Acid Sequence↗
PubMed1991

[Studies on the chemical constituents of Dendrobium loddigesii rolfe].

According to IR, UV, MS and NMR spectra of the compounds isolated from the fresh stem of Dendrobium loddigesii Rolfe (a Chinese medicine), 3 constituents were identified. They are shihunidine, shihunine and dendrophenol (4,4'- dihydroxy-3,3',5-trimethoxybibenzyl). Chemical reactions showed that shihunidine was derived from shihunine during isolation. Shihunidine and shihunine were shown to be inhibitors of Na+, K+-ATPase of the rat kidney.

Animals↗
PubMed1991

[Bayesian and RFLP linkage analysis on a DMD family].

Three methods were applied to estimate the carrier risk of the daughter of an obligate carrier of the Duchenne gene in a pedigree of Duchenne muscular dystrophy (DMD). According to Mendel's law of segregation, the daughter (III-3) of the obligate carrier (II-2) has a 50% chance of being a carrier. III-3 is also found to have a normal value in a carrier test, creatine phosphate kinase (CPK), and so the Bayesian analysis in risk estimation shows that the posterior probability that she is a carrier (25%). The restriction fragment length polymorphism (RFLP) linkage analysis indicates that the probability that III-3 is a carrier less than 5%. This result can be included in the Bayesian analysis to give an even lower risk of less than 2%. Our study demonstrates that the best result of carrier risk estimation can be obtained by a simultaneous application of Mendel's law, RFLP linkage analysis and the Bayesian analysis.

Bayes Theorem↗
PubMed1991

[The dilatation effect of local anesthetics on the cervix during surgical termination of early pregnancy].

The dilatation effect of Anodyne-Lubricant Jelly (ALJ) containing Dicaini, Lidocaine and placebos on the cervix during surgical termination of the first trimester pregnancy was observed in 372 women. The results showed that there was no significant difference in the drug induced dilatation rates between ALJ and placebo (P less than 0.25), and between Lidocaine and placebo (P = 0.4287). However, when the ALJ and placebo were applied intracervically. The induced dilatation rate was significantly higher than those of lidocaine and placebo given by injection (P less than 0.005). The findings suggest that the effect of ALJ on cervical dilatation may not be associated with Dicaini, but rather with the lubricant applied into the cervical canal.

Abortion, Induced↗
PubMed1990

Randomized trial of the effect of drugs on cervical dilatation for termination of first trimester pregnancy.

A randomized triple-blind and placebo-controlled clinical trial on the effect of lidocaine and Anodyne-lubricant jelly (ALJ) containing dicaine on cervical dilatation is reported. Three-hundred-seventy-two consecutive cases were randomly allocated to 4 groups. The four groups were given: ALJ and placebo (placebo 1); and lidocaine and placebo (placebo 2). ALJ and placebo 1 treatment was by topical application, and lidocaine and placebo 2 by injection. In parous women, a significant difference was found for satisfactory dilatation (SD) rate (p less than 0.01) among four groups. It was unexpected that there were no significant differences between drug and placebo groups, neither between ALJ treatment group and placebo 1 group (p greater than 0.5), nor between lidocaine and placebo 2 (p greater than 0.75). However, the combined SD rate was 60.9% for the topical groups compared with 39.0% for the injection groups (p less than 0.005). The findings suggested that the effect of ALJ on cervical dilatation was not mainly due to dicaine, but associated with the lubricant and the topical treatment.

Abortion, Induced↗
PubMed1990

Preliminary study on the microbiology of Campylobacter pyloridis and gastric histopathology.

Biopsy samples were taken endoscopically from the antral-mucosa of 693 patients with peptic ulcer and chronic gastritis presenting dyspepsia symptoms. Campylobacter pyloridis cultures were positive in 59 of 98 (60.2%) cases and histopathologically the organisms were found in 411 of 693 cases (59.3%). Pathologically, Campylobacter pyloridis was positive in 273 out of 300 patients with chronic superficial gastritis (91.0%), in 102 of 249 patients with chronic atrophic gastritis (40.9%), in 36 out of 144 patients with chronic atrophic gastritis with intestinalization or dysplasia (25.0%). We found that there was a significant association between the presence of Campylobacter pyloridis and chronic superficial gastritis, also the degree of lymphocyte infiltration showed a strong inverse association with the presence of Campylobacter pyloridis, suggesting that a local immune response might exert an important action in the eradication of this organism. These findings support the view that Campylobacter pyloridis, may be etiologically related to chronic gastritis and peptic ulceration, even though its role still remains to be determined.

Campylobacter↗
PubMed1989

[Microscopical examination of leaf sheathes of the Chinese drug "Shihu", herba dendrobii].

"Shihu", a famous Chinese traditional drug, is used to replenish the vital essence of the lung and stomach, to clear up the excessive heat and to promote the secretion of the body fluid. The commercial crude drugs under the general name "Shihu" are mostly derived from a number of species of the genus Dendrobium. It is difficult to identify exactly the botanical origin of these crude drugs through macroscopical examination. In order to tackle this problem, the leaf sheathes of the stems of 16 species of the genus Dendrobium are examined microscopically and the characteristics of their epidermal cells and calcium oxalate crystals are compared. The diagnostic features found are proved to be useful for the identification of the botanical origin of commercial samples of the "Shihu". In this paper the microscopical characters of 16 Dendrobium species are described with illustration.

Calcium Oxalate↗