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Biomedical subjects

M Y Tan

Publications and source records attributed to M Y Tan.

10 recordsLinked to original sources
PubMed2001

Phenol-oxidizing peroxidases contribute to the protection of plants from ultraviolet radiation stress.

We have studied the mechanism of UV protection in two duckweed species (Lemnaceae) by exploiting the UV sensitivity of photosystem II as an in situ sensor for radiation stress. A UV-tolerant Spirodela punctata G.F.W. Meyer ecotype had significantly higher indole-3-acetic acid (IAA) levels than a UV-sensitive ecotype. Parallel work on Lemna gibba mutants suggested that UV tolerance is linked to IAA degradation rather than to levels of free or conjugated IAA. This linkage is consistent with a role for class III phenolic peroxidases, which have been implicated both in the degradation of IAA and the cross-linking of various UV-absorbing phenolics. Biochemical analysis revealed increased activity of a specific peroxidase isozyme in both UV-tolerant duckweed lines. The hypothesis that peroxidases play a role in UV protection was tested in a direct manner using genetically modified tobacco (Nicotiana sylvestris). It was found that increased activity of the anionic peroxidase correlated with increased tolerance to UV radiation as well as decreased levels of free auxin. We conclude that phenol-oxidizing peroxidases concurrently contribute to UV protection as well as the control of leaf and plant architecture.

Indoleacetic Acids↗
PubMed1999

Improvement of the in vitro dissolution of praziquantel by complexation with alpha-, beta- and gamma-cyclodextrins.

Although praziquantel (PZQ) is the primary drug of choice in the treatment of schistosomiasis, its poor solubility has restricted its delivery via the oral route. In spite of its poor solubility, PZQ is well absorbed across the gastrointestinal tract, but large doses are required to achieve adequate concentrations at the target sites. Improving the solubility would enable the parenteral route to be used, thereby avoiding significant first pass metabolism. The aqueous solubility of PZQ was improved by forming inclusion complexes with alpha-, beta- and gamma-cyclodextrins (CDs). These complexes were assessed and confirmed by solubility analysis, Fourier transform infrared analysis, elemental analysis, differential scanning calorimetry and mass spectrometry. Dissolution of PZQ from the alpha-, beta- and gamma-CD complexes was 2.6-, 5- and 8-fold greater, respectively, than that of the pure drug. However, only the beta-complex had a stability constant in the optimum range for pharmaceutical use, suggesting that the preferred complex for further development would be a water-soluble beta-CD derivative.

Antiplatyhelmintic Agents↗
PubMed1998

The Mitchell distal metatarsal osteotomy for hallux valgus--the Singapore General Hospital experience.

BACKGROUND: Fifty-five Mitchell distal metatarsal osteotomies for hallux valgus performed over a period of four years have been retrospectively reviewed. The 38 patients were followed for an average of 30 months (range 12 to 60 months). RESULTS: The preoperative hallux valgus angle averaged 30.9 degrees +/- 8.2 degrees SD (range 18 degrees to 60 degrees) and the postoperative angle averaged 12.2 degrees +/- 4.6 degrees (range 5 degrees to 20 degrees). CONCLUSION: Ninety-two percent of the patients were satisfied with the result of the procedure. They stated that, given the identical situation, they would undergo the operation again.

Adult↗
PubMed1998

Chevron osteotomy for hallux valgus--SGH experience.

Thirty-one chevron osteotomies for hallux valgus performed over a period of four years were reviewed. Their follow-up period ranged from one to five years. All the patients had pain over the bunion prior to operation. After operation, there was marked decrease of pain over the first matatarsophalangeal joint. The preoperative hallux valgus angle average 27 degrees and the postoperative angle averaged 12 degrees. The preoperative intermetatarsal angle averaged 13 degrees and the postoperative angle, 8 degrees. Ninety-one per cent of the patients were satisfied with the result of the procedure.

Adult↗
PubMed1997

Anterior cruciate ligament reconstruction using patellar tendon autografts--a review of results.

AIM: The aim of this retrospective study was to review the results of anterior cruciate ligament reconstruction using patellar tendon autografts. METHODS: Forty-one knees were available for evaluation at a minimum of 24 months follow-up. Objective, subjective, functional and KT-1000 arthrometric tests were performed. RESULTS: 92.7% had a negative or trace pivot shift at follow-up. None of the patients had rupture of the autografts at review. The mean post-operative single-legged hop was 81%. The KT-1000 arthrometric evaluation post-operatively revealed a mean maximum manual difference of 0.5 mm; 90.2% of these patients had a maximum manual difference of less than 4 mm. Five patients (12.2%) had a "tighter" reconstructed knee (a negative mean maximum manual difference). More than 70% of the patients in this series had good to excellent results on functional, subjective and objective evaluation scores. CONCLUSION: Excellent motion recovery, reliable stabilisation rates, good arthrometric results and encouraging post-operative functional, subjective and objective evaluation scores can be expected in patients undergoing anterior cruciate ligament reconstruction with patellar tendon autografts.

Adult↗
PubMed1994

[Pharmacognostical identification and investigation of commercial product of traditional Chinese drug jiuyanduhuo].

Through investigation on original plants and commercial products of the traditional Chinese drug Jiuyanduhuo, the authors have ascertained its botanical origin and present medicinal usage, and found out that Aralia cordata is the main species of Jiuyanduhuo, and A. fargesii is another species that has come into use due to short supply of the main species, and A. henyri is used only in Sichuan and Hubei Provinces. Principal identification features of the original plants and crude drugs with 2 keys have been given, and TLC identification for 3 kinds of Jiuyanduhuo have also been carried out.

China↗
PubMed1994

De Quervain's tenosynovitis and ganglion over first dorsal extensor retinacular compartment.

Between 1988 to 1991, 80 cases of de Quervain's disease were managed at the Department of Orthopaedic Surgery, Singapore General Hospital. Six of them had an associated ganglion over the first dorsal retinacular compartment. Five out of 6 cases had intracompartment injections of hydrocortisone and lignocaine but the treatment was not effective in relieving the pain of de Quervain's tenosynovitis. All 6 cases had excision of the ganglion and decompression of the first extensor compartment. All the lumps were found arising from the dorsal aspect of the retinaculum and no intracompartment extension of the ganglion was found.

Female↗