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Biomedical subjects

S Y Ying

Publications and source records attributed to S Y Ying.

At least 37 records · Page 2Linked to original sources
PubMed2001

Assault by burning--a reappraisal.

Assault by burning is a serious form of trauma that often results in higher incidence of inhalation injury, longer intensive care unit (ICU) and hospital stay, and higher mortality rate than is observed in the general burn population. We evaluated the epidemiology and outcome of assault burn victims treated in a tertiary burn center over a 6-year period. Among the 1063 acute burn patients who had been admitted to the Burns Unit between March 1993 and February 1999, 28 (2.6%) had assault burn injuries either by scald, chemical or fire. The mean extent of burn was 21.9%+/-20.8% (range 2-90%) total body surface area and the mean length of hospital stay was 65.2+/-107.3 days (range 1-565). Nineteen out of 25 patients (67.9%) underwent 76 operations. Nine patients had inhalation injuries requiring intubation and ICU admission. Three patients died in the series, which yielded a mortality rate of 10.7%. Compared to the general burn population, the assault burn group had significantly larger burn size (P<0.001), higher incidence of inhalation injury (P<0.001), longer ICU and hospital stay (P<0.001), and higher mortality rate (P<0.005). When these 28 victims were grouped according to the type of assault burn injury into a fire group, chemical group and scald group, all the 9 ICU admission and the 3 mortalities belonged to the fire group. Assault by fire resulted in larger burn size (P=0.03), more inhalation injury (P<0.001) and longer ICU stay (P=0.02). Although the fire group had a longer hospital stay and higher mortality rate, this was statistically insignificant.

Adolescent↗
PubMed2001

Skin care in burn patients: a team approach.

Skin care is an important but often neglected issue in burn management. Newly healed burn skin is fragile, itchy, dry, and susceptible to sunburn. Without proper skin care in burn patients, they may suffer from sleep and mood disturbances, depression, and poor compliance to treatment that can jeopardize the rehabilitation process. At the Prince of Wales Hospital, skin care has been managed since February 1996 by a team consisting of plastic surgeon, dermatologist, occupational therapist and nursing specialist. The purpose of this study was to evaluate the impact of a skin care program run by a Skin Care Team on the rehabilitation of burn patients in a tertiary burn centre. The role of different members of the team was also discussed.

Adolescent↗
PubMed2001

A prospective controlled clinical study of skin donor sites treated with a 1-4,2-acetamide-deoxy-B-D-glucan polymer: a preliminary report.

The effect of Hyphecan (1-4,2-acetamide-deoxy-B-D-glucan) on skin donor site healing was compared with the standard skin donor site dressing Kaltostat (calcium sodium alginate) in 35 burn patients with 70 skin donor sites prospectively. The median time of wound healing for the Hyphecan group was 12 days with an average of 13.1+/-4.0 days (ranged from 9 to 28 days) while the Kaltostat group had a median healing time of 12 days (ranged from 8 to 28 days) with a mean of 13.0+/-4.1 days. The difference in healing time between these two groups was statistically insignificant with a P-value of 0.95. The infection rate was 2.9% for both Hyphecan and Kaltostat. These 35 patients had been followed up from 10 to 16 months and no difference in long-term donor site morbidity between Hyphecan and Kaltostat had been observed. This finding was encouraging because the cost of Hyphecan is less than 50% of Kaltostat and it may be worthwhile to explore the clinical application of Hyphecan in other area of burns treatment.

Adolescent↗
PubMed2001

An in vivo study comparing the efficacy and complications of diode laser and long-pulsed Nd:YAG laser in hair removal in Chinese patients.

BACKGROUND: Lasers with long wavelengths are less well absorbed by melanin and are considered to be particularly suitable for hair removal in dark-skinned patients. OBJECTIVE: To compare the efficacy and complications of 800 nm diode and long-pulsed 1064 nm Nd:YAG lasers in laser-assisted hair removal in Chinese patients. METHODS: Fifteen women had hair removal treatments (13 axillae and 2 legs) with diode laser on one side and Nd:YAG laser on the other. They were followed up for 36 weeks. Subjective assessments included the degree of immediate pain and the degree of hair regrowth. Clinical photographs were taken for evaluation by two independent observers to assess complications and the degree of hair regrowth. RESULTS: Long-pulsed Nd:YAG laser was found to be significantly associated with a greater degree of immediate pain after laser surgery (P =.0001, independent sample t-test) and also had a longer laser time (P =.0001, independent sample t-test). Besides transit adverse effects such as erythema and perifollicular edema, only one patient developed hypopigmentation at week 6 which resolved by week 36. Although regrowth rates were low at week 6 (subjective rates were 23% and 19% for Nd:YAG and diode laser, respectively), most patients had significant regrowth at week 36 (subjective regrowth rate 91% for both long-pulsed Nd:YAG and diode lasers). CONCLUSION: Diode 800 nm and Nd:YAG 1064 nm lasers are safe in laser-assisted hair removal in Chinese patients, and besides immediate pain, there was no other significant adverse effect. Most patients experienced regrowth 36 weeks after a single treatment. Further study is necessary to determine the long-term clinical efficacy and complications of laser-assisted hair removal with these systems in dark-skinned patients.

Adult↗
PubMed2001

D-RNAi (messenger RNA-antisense DNA interference) as a novel defense system against cancer and viral infections.

D-RNAi (Messenger RNA-antisense DNA interference), a novel posttranscriptional phenomenon of silencing gene expression by transfection of mRNA-aDNA hybrids, was originally observed in the effects of bcl-2 on phorbol ester-induced apoptosis in human prostate cancer LNCaP cells. This phenomenon was also demonstrated in chicken embryos and a human CD4(+) T cell line, H9. The in vivo transduction of beta-catenin D-RNAi was shown to knock out more than 99% endogenous beta-catenin gene expression, while the in cell transfection of HIV-1 D-RNAi homolog rejected viral gene replication completely. D-RNAi was found to have long-term gene knockout effects resulting from a posttranscriptional gene silencing mechanism that may involve the homologous recombination between intracellular mRNA and the mRNA components of a D-RNAi construct. These findings provide a potential intracellular defense system against cancer and viral infections.

DNA, Antisense↗
PubMed2000

Bizarre paediatric facial burns.

Child abuse and neglect account for a significant number of paediatric burn injuries. It is of great importance because of the high mortality, high frequency of repeated abuse, as well as the physical, psychological and social sequelae that it causes. Burn abuse is often under-recognized and under-reported because it is difficult to define non-accidental injury. On the other hand, false accusation of burn abuse is extremely damaging to the family. Bizarre and unusual burn injuries can be caused by accident and should not automatically be assumed to be deliberate injury. Three boys of age 1-7 years with bizarre facial burns were admitted to the Burns Unit at the Prince of Wales Hospital between February 1995 and July 1999. One was burned by his baby-sitter with hot water steam and the other two were burned by their mothers with hot boiled eggs. The unusual causes of their burns raised the suspicion of child abuse and formal investigations were carried out by the Social Services Department. Detail assessment including a developmental history of the child and the psychosocial assessment of the family revealed that these three boys were burned because of poor medical advice and innocent cultural belief.

Burns↗
PubMed2000

Iatrogenic burn caused by an alcohol lamp.

Iatrogenic injury is an intrinsic risk of all medical procedures. Various kinds of iatrogenic complications have been extensively reported and recognized. Two patients were referred to the Prince of Wales Hospital for iatrogenic flame burn caused by the breakage of an alcohol lamp during ENT examination. They were 8 and 9 years old and sustained 12 and 17% intermediate to deep dermal burns respectively. There was no eye or inhalation injury. They were treated initially at the referring hospital. Despite having the best possible treatment, the parents were hostile to and demanding of the medical attendants and the patients were uncooperative throughout the whole treatment period. Rehabilitation of the two children was jeopardized. The situation was very difficult when they were first seen at the Prince of Wales Hospital. The burn surgeon at the Prince of Wales Hospital, as a third party, managed to act as a bridge between the referring hospital and the patients and their families. Several meetings were held and the best interests of the two patients was addressed. The compensation issue was also settled without formal legal prosecution.

Alcohols↗
PubMed2000

The use of variable pulse width frequency doubled Nd:YAG 532 nm laser in the treatment of port-wine stain in Chinese patients.

BACKGROUND: Variable pulse width frequency doubled Nd:YAG 532 nm laser has previously been shown to be effective in the treatment of vascular lesions in Caucasians. For dark-skinned patients, such as Asians, its role has not been determined. OBJECTIVE: To assess the clinical efficacy and complication rate of the 532 nm Nd:YAG laser in the treatment of port-wine stain in Chinese patients. METHODS: Chinese patients with port-wine stain who had undergone Nd:YAG laser treatment were called for questionnaire assessment of their degree of clearing and clinical examination for complications by two independent observers. For 22 patients with pre- and posttreatment photographs, the two independent observers further assessed the degree of clearing. RESULTS: Assessment of the questionnaire indicated that 62.9% of the patients subjectively considered that they had more than 25% clearing, with 33.3% having more than 50% clearing. For those with pre- and posttreatment photographs, the objective degree of improvement was less impressive with 18.1% of patients having at least 25% improvement and only 13.6% having more than 50% improvement. Pigmentary and texture changes were seen in both groups (33% in group I and 11% in group II). The number of treatment sessions rather than previous use of pulsed dye laser therapy was an important risk factor for complications. CONCLUSION: Nd:YAG laser is only partially effective for the treatment of port-wine stain in Chinese patients. Although most patients recorded some degree of subjective improvement, many did not improve by objective assessment. High fluence is necessary to achieve the desirable clinical response, and while contact cooling reduces the risk of epidermal damage, texture changes can still occur. Further study is necessary to compare its use with other similar devices, such as a pulsed dye laser with cryogen spray cooling.

Adult↗
PubMed2000

An in vivo trial comparing the use of different types of 532 nm Nd:YAG lasers in the treatment of facial lentigines in Oriental patients.

BACKGROUND: Versapulse is a system that consists of four laser modalities and was developed with the aim of increasing cost-effectiveness. However, as these lasers share a common power supply, for the Q-switched (QS) Nd:YAG 532 nm laser a large spot diameter is necessary to lower the fluence to a suitable level. This can increase the risk of hyperpigmentation when used for the treatment of lentigines in dark-skinned patients. OBJECTIVE: The aim of our study was to access the clinical efficacy and the complication rate of the Versapulse QS Nd:YAG 532 nm laser, the Versapulse long-pulsed Nd:YAG 532 nm laser (without the chill tip), and a conventional QS Nd:YAG 532 nm laser in the treatment of lentigines in Chinese patients. METHODS: Thirty-four Chinese patients with lentigines were randomized to receive laser surgery, with one side of the face treated by one laser and the other side treated by a different system. Patients were monitored for 6 weeks to assess the degree of clearing, hyperpigmentation, hypopigmentation, and erythema. Assessments involved patients interviewed using a visual analog questionnaire and two blinded observers who evaluated the pre- and posttreatment clinical photographs. RESULTS: The Versapulse QS Nd:YAG 532 nm laser was associated with a statistically higher risk of complications. The Versapulse long-pulsed Nd:YAG 532 nm laser was compatible with the conventional QS Nd:YAG 532 nm laser in terms of clinical efficacy and complication rates. CONCLUSION: The Versapulse long-pulsed 532 nm laser is more effective and should be used instead of the Versapulse QS Nd:YAG 532 nm laser for the treatment of lentigines in dark-skinned patients.

Adult↗
PubMed2000

An in vivo trial comparing the clinical efficacy and complications of Q-switched 755 nm alexandrite and Q-switched 1064 nm Nd:YAG lasers in the treatment of nevus of Ota.

BACKGROUND: Q-switched 755 nm alexandrite (QS alex) and Q-switched 1064 nm Nd:YAG lasers are effective in the treatment of nevus of Ota. Our previous in vivo study indicated that patients better tolerate QS alex than QS 1064 nm Nd:YAG laser. However, in terms of clinical efficacy and long-term complications, the study did not indicate which laser is superior. Although both machines may appear to be similar in effectiveness, the low number of treatment sessions may contribute to this apparent lack of difference. OBJECTIVE: The aim of this study was to compare the clinical efficacy and complications of QS 755 nm alex and QS 1064 nm Nd:YAG lasers in the treatment of nevus of Ota after three or more treatment sessions. METHOD: Forty patients were recruited for this study and all had received three or more laser treatment sessions with an interval of at least 2 months between each. Half of the lesion was treated with QS alex and the other half with QS 1064 nm Nd:YAG laser. The degree of lightening was assessed subjectively by the patient using a visual analog scale and objectively by two independent clinicians. Patients were called back to be examined for evidence of complications. RESULTS: In terms of subjective degree of lightening, QS 1064 nm Nd:YAG laser was found to be significantly more efficacious than QS alex (P = 0.018). Both clinicians also found QS 1064 nm Nd:YAG laser to be more effective, but statistical significance was only detected in one, not both of their scores (P = 0.005 and 0.414 for observers 1 and 2, respectively). More patients that received QS Alex developed complications (4 for QS alex and 2 for QS Nd:YAG), but the difference was not statistically significant. CONCLUSION: QS 1064 nm Nd:YAG laser appears to be more effective than QS alex in the lightening of nevus of Ota after three or more laser treatment sessions. However, the majority (55%) of the patients reported no differences in results between the two lasers, and only one of the two observers noted statistically significant improvement of QS 1064 nm Nd:YAG over QS alex.

Adolescent↗
PubMed2000

A retrospective analysis of complications in the treatment of nevus of Ota with the Q-switched alexandrite and Q-switched Nd:YAG lasers.

BACKGROUND: Studies on the use of Q-switched alexandrite (QS alex) and QS Nd:YAG lasers in the treatment of nevus of Ota were limited to case reports and small series. There was no study that looked at the complication rate of these systems. OBJECTIVE: To retrospectively study the complication rate of nevus of Ota patients that were treated with QS alex laser, QS Nd:YAG laser, or a combination of both. METHODS: The study was performed in a teaching hospital and a private hospital, where 513 patients with nevus of Ota had been treated since 1993. The 171 patients with 211 treatment sites were evaluated retrospectively following treatment with QS alex laser only (n = 58), QS Nd:YAG laser (n = 105) only, or a combination of both systems (n = 48). Patients were called back to be interviewed and examined by two independent clinicians to look for evidence of complications. RESULTS: Of the treatment sites, 15. 3% had hypopigmentation, 2.9% had hyperpigmentation, and texture changes and scarring were seen in 2.9% and 1.9%, respectively. The combined treatment group was associated with a significantly higher risk of complications. Thirteen patients had recurrence of their nevus after complete or near-complete clearance with laser treatment. CONCLUSION: Hypopigmentation is common after the use of QS laser for lightening of nevus of Ota. This particularly applies when alternate treatment with QS alex and QS Nd:YAG is used. Recurrence is an important issue and must be taken into consideration, especially when children are treated.

Adolescent↗
PubMed1999

In vivo analysis of cancerous gene expression by RNA-polymerase chain reaction.

An easy and routine procedure to amplify messenger RNA (mRNA) libraries from a few tissue cells can provide molecular gene expression profiles at high resolution. A novel PCR-like method, the RNA-PCR, was developed to generate high quality and quantity mRNAs from as few as 20 cells (2 pg mRNAs). The principle relies upon the cycling steps of promoter-linked double-stranded cDNA synthesis and promoter-driven transcription to amplify mRNAs up to 250-fold/cycle with good representation of high and low copy mRNAs. The amplified mRNA libraries were shown to possess high fidelity, purity, specificity and reproducibility for in vivo analyses of cancerous gene expression in human prostate cancers.

Base Sequence↗
PubMed1999

Suppression of activin-induced apoptosis by novel antisense strategy in human prostate cancer cells.

Apoptosin, a novel gene encoding a mitotic kinase-motif protein, is stimulated by activin, a member of TGF-beta family, in human LNCaP prostate cancer cells and in patient tissues. We employed a gene knockout methodology based on the covalent bonding of chemically modified antisense probes to apoptosin mRNAs in LNCaP cells. The mRNA-antisense hybrid duplexes were neither translated nor post-transcriptionally modified, resulting in no protein synthesis. Introducing antisense apoptosin into activin-induced apoptotic LNCaP cells prevented apoptosis, interfered with genomic DNA fragmentation and released cell cycle checkpoint. These findings suggest that the apoptosin, in addition to p53, is important in apoptotic regulation of human prostate cancers.

Activins↗
PubMed1999

Differentially expressed genes in activin-induced apoptotic LNCaP cells.

Gene transcripts differentially expressed in activin-induced human prostatic LNCaP apoptotic cells have been discovered by an improved subtractive hybridization method, uracil-DNA subtraction assay (USA), which involves digestion with uracil-DNA glycosylase and mung-bean nuclease. Among the five up-regulated and seven down-regulated genes, we have identified six known (>95% homology and similar size; p16, p53, Siva, RHAMM, Pax2, and eIF-4a1), three homologues (>95% homology but different size; myosin, a helicase motif, and a kinase motif), and three novel genes (no homology). In addition, anti-sense knock-out of a resulting novel kinase-like gene was found to abolish the apoptotic DNA fragmentation in activin-treated LNCaP cells. These findings indicate a new potential mechanism in DNA fragmentation of activin-induced cell-cycle arresting and apoptosis.

Activins↗
PubMed1999

High-performance subtractive hybridization of cDNAs by covalent bonding between specific complementary nucleotides.

We have developed an improved subtractive hybridization method that provides a fast, simple and reliable isolation of desired different sequences from two compared DNA libraries, one of which contains all unwanted homologues (subtracter) and another contains certain desired heterologues (tester). The DNA library can be made from either mRNA or genomic DNA. An excess amount of modified subtracter DNA from control cells was generated by chemical carboxylation of the pyrimidines to provide covalent affinity to the purines of a natural tester DNA. Hybridization of the control subtracter and the experimental tester DNA was performed with a heat-melting and then cool-reassociation technique. The desired different sequences remained in the form of hydrogen-bonded, homologous sequences of both libraries covalently bonded to each other, resulting in no separation during PCR and cloning. Consequently, the DNA sequences obtained from the covalent homology subtraction represent the nucleotide sequences abundant in the tester but rare in the subtracter library.

Activins↗
PubMed1999

Detection of small lesions in alveolar bone by digital subtraction radiography.

OBJECTIVE: To evaluate the effectiveness of digital subtraction radiography (DSR) system for diagnosis of small artificial alveolar bone lesions. METHODS: Seventy-two 0.2-0.9 mm3 lesions were produced in premolar and molar areas of dry human mandibles. Reference and subsequent radiographs were taken before and after lesions were made. The small lesions were detected by conventional radiography and DSR respectively. RESULTS: For 0.2-0.5 mm3 lesions, detection by both DSR and conventional methods was less than 50%. For 0.7 mm3 lesions, the detection by DSR and conventional methods was 57.5% and 38.7%, respectively (P < 0.01). For 0.9 mm3 lesions, the accuracy of the detection by DSR and conventional methods was 89.3% and 57.3% (P < 0.01). CONCLUSION: The detectability of small alveolar bone lesions by DSR was superior to that of the conventional method.

Alveolar Bone Loss↗