Biomedical subjects

W S Ho

Publications and source records attributed to W S Ho.

At least 37 records · Page 2Linked to original sources

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

Mechanisms of anandamide-induced vasorelaxation in rat isolated coronary arteries.

1. The cannabinoid arachidonyl ethanolamide (anandamide) caused concentration-dependent relaxation of 5-HT-precontracted, myograph-mounted, segments of rat left anterior descending coronary artery. 2. This relaxation was endothelium-independent, unaffected by the fatty acid amide hydrolase inhibitor, arachidonyl trifluoromethyl ketone (10 microM), and mimicked by the non-hydrolysable anandamide derivative, methanandamide. 3. Relaxations to anandamide were attenuated by the cannabinoid receptor antagonist, SR 141716A (3 microM), but unaffected by AM 251 (1 microM) and AM 630 (1 microM), more selective antagonists of cannabinoid CB(1) and CB(2) receptors respectively. Palmitoylethanolamide, a selective CB(2) receptor agonist, did not relax precontracted coronary arteries. 4. Anandamide relaxations were not affected by inhibition of sensory nerve transmission with capsaicin (10 microM) or blockade of vanilloid VR1 receptors with capsazepine (5 microM). Nevertheless capsaicin relaxed coronary arteries in a concentration-dependent and capsazepine-sensitive manner, confirming functional sensory nerves were present. In contrast, capsazepine and capsaicin did inhibit anandamide relaxations in methoxamine-precontracted rat small mesenteric arteries. 5. Relaxations to anandamide were inhibited by TEA (1 mM) or iberiotoxin (50 nM), blockers of large conductance, Ca(2+)-activated K(+) channels (BK(Ca)). Gap junction inhibition with 18alpha-glycyrrhetinic acid (100 microM) did not affect anandamide relaxations. 6. This study shows anandamide relaxes the rat coronary artery by a novel mechanism. Anandamide-induced relaxations do not involve the endothelium, degradation into active metabolites, or activation of cannabinoid CB(1) or CB(2) receptors, but may involve activation of BK(Ca). Vanilloid receptor activation also has no role in the effects of anandamide in coronary arteries, even though functional sensory nerves are present.

Amides↗

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

A retrospective study on the efficacy and complications of Q-switched alexandrite laser in the treatment of acquired bilateral nevus of Ota-like macules.

BACKGROUND: Acquired bilateral nevus of Ota-like macules (ABNOM), or Hori's macules, is a common Asian condition that is characterized by bluish hyperpigmentation in the bilateral malar regions. Unlike nevus of Ota, ABNOM is an acquired condition that often develops after 20 years of age and involves both sides of the face, but there is no mucosal involvement. Recently Q-switched (QS) 1064 nm Nd:YAG lasers have been effective in clearing this condition. The effectiveness of QS alexandrite lasers has not yet been studied. OBJECTIVE: To retrospectively assess the efficacy and complications of QS alexandrite lasers in the treatment of ABNOM. METHODS: Thirty-two Chinese women with ABNOM ranging in age from 28 to 66 years were involved in the study. All underwent QS alexandrite laser treatment (755 nm, spot size 3 mm, 8 J/cm(2)). Topical hydroquinone and tretinoin cream were given to those with hyperpigmentation after the laser surgery. Clinical photographs were taken before and after laser surgery and assessed by two independent observers. The degree of clearing was scored and complications, including hypopigmentation, hyperpigmentation, scarring, and erythema, were assessed. RESULTS: The mean number of treatment sessions was 7 (range 2-11) and the mean treatment interval was 33 days. Both observers identified more than 80% of the patients as having more than a 50% degree of clearing, and complete clearance was seen in more than 28% of patients. Although most patients had postlaser hyperpigmentation and were on depigmentary regimes, the hyperpigmentation was seen in only 12.5% of the patients during photographic evaluation. Hypopigmentation was seen in 50% of patients and erythema in 41%. CONCLUSION: QS alexandrite appears to be effective in the treatment of ABNOM. Postoperative pigmentary changes were frequent and the use of topical depigmentary agents was necessary to achieve a satisfactory result. Transient hypopigmentation risk was high, affecting up to 50% of the patients. Further study is warranted to compare the efficacy and complications of different laser systems in the treatment of this condition.

Adult↗

PubMed2001

A prospective study of the effect of botulinum toxin A on masseteric muscle hypertrophy with ultrasonographic and electromyographic measurement.

We evaluated the effect of botulinum toxin A on masseteric muscle hypertrophy by using ultrasound and electromyography. Five patients (four with bilateral and one with unilateral masseteric muscle hypertrophy) were studied prospectively. In each patient, ultrasound-guided percutaneous intramuscular injection of botulinum toxin A was carried out. The change in muscle bulk was evaluated using serial ultrasonography and the electrical activity was assessed with electromyography. All five patients (nine hypertrophic muscles) showed a good response, with the maximal effect of a 31% reduction in muscle bulk seen 3 months after treatment. The effect remained stable one year after injection for six of the hypertrophic muscles, whereas three muscles needed a second injection to maintain the atrophy. This preliminary prospective study suggests that botulinum toxin A is a safe alternative method of treating masseteric muscle hypertrophy. However, the effect may be temporary and further intramuscular injection may be required to maintain atrophy.

Adolescent↗

PubMed2001

Management of paraffinoma of the breast: 10 years' experience.

Paraffin injection was regarded as a simple and effective method of improving body contour. It was widely used in breast augmentation until the long-term complication of paraffinoma was recognised. Paraffinoma of the breast can present as a spectrum of disease ranging from a painless mass to a destructive ulcer simulating breast cancer. This makes it difficult to make the correct diagnosis and provide suitable treatment. Eight patients with paraffinoma of the breast have been managed at a teaching hospital over a 10 year period. All were females, with a mean age of 65.6 years (range: 57-73 years). The average time between paraffin injection and the onset of symptoms was 24 years (range: 11-30 years). These patients have been followed up for between 3 and 10 years (mean: 6.1 years). One patient died of congestive heart failure 4 years after bilateral mastectomy for painful paraffinomas of the breasts. Another patient had a coexisting infiltrative ductal carcinoma of the breast. The clinical presentations, radiological appearances, histopathological features and the treatment are discussed.

Aged↗

PubMed2001

Odontogenic subperiosteal abscess of orbit: a case report.

Subperiosteal abscess of orbit is an uncommon but serious complication of orbital infection. We report a case of a 78 year old gentleman who presented with bilateral periorbital oedema and proptosis. Computerised tomography of orbit revealed bilateral dilated superior ophthalmic veins. Bilateral carotid-cavernous fistula was initially suspected. Serial imaging showed an increasing bilateral subperiosteal lesion of the orbit. Fine needle aspiration confirmed subperiosteal abscess. A high level of awareness is necessary in diagnosing subperiosteal abscess.

Abscess↗

PubMed2001

Effect of the blood substitute diaspirin crosslinked hemoglobin in rat mesenteric and human radial collateral arteries.

The actions of the blood substitute diaspirin crosslinked hemoglobin (DCLHb) were investigated in rat (small mesenteric artery) and human (radial collateral artery) resistance vessels mounted in a wire myograph for isometric tension recording. DCLHb did not contract resting vessels from rats, but vasoconstrictor responses were observed in isolated arteries and perfused mesenteric beds prestimulated with threshold concentrations of methoxamine. The DCLHb contractile responses were greatly attenuated by N(G)-nitro-L-arginine methyl ester hydrochloride (L-NAME) or endothelial removal, whereas BQ-123 (endothelin A receptor antagonist), prazosin (alpha1-adrenoceptor antagonist), or indomethacin (cyclooxygenase inhibitor) had no effect. Endothelium-dependent relaxations to carbachol in both rat mesenteric and human radial collateral artery were inhibited by DCLHb. Relaxations to carbachol were studied in the presence of L-NAME or 25 mM KCl to investigate the effect of DCLHb on endothelium-derived hyperpolarizing factor (EDHF) and nitric oxide, respectively. In both rat and human vessels, EDHF-mediated relaxations were not affected by DCLHb preincubation, whereas the nitric oxide component of carbachol-induced relaxations was practically abolished. In conclusion, inhibition of the effects of basal nitric oxide release underpins the vasoconstrictor effects of DCLHb. DCLHb effectively abolishes the nitric oxide component of carbachol-induced relaxation, with no effect on the EDHF-mediated component in both isolated rat mesenteric and human radial collateral arteries.

Animals↗

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

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↗

PubMed2000

The use of liposucker for spleen retrieval after laparoscopic splenectomy.

The retrieval of spleen after laparoscopic splenectomy has long been a problem. Frequently, it is necessary to extend the wound for retrieving the spleen intact and to prevent potential spillage of splenic tissue into the peritoneal cavity. We describe the application of the liposuction unit to remove the spleen piecemeal after laparoscopic splenectomy. We have found this technique easy to apply and safe, without the necessity of excessive wound extension, while preserving splenic tissue for histologic examination.

Adult↗

PubMed1999

In vivo trial comparing patients' tolerance of Q-switched Alexandrite (QS Alex) and Q-switched neodymium:yttrium-aluminum-garnet (QS Nd:YAG) lasers in the treatment of nevus of Ota.

BACKGROUND AND OBJECTIVES: Different types of Q-switched lasers have been found to be effective in the treatment of nevus of Ota. However, a clinical trial involving in vivo comparison of the use of different laser systems has not been performed. The aim of the present study was to compare the patient tolerance of Q-switched Alexandrite (QS Alex) and Q-switched neodymium:yttrium-aluminum-garnet (QS Nd:YAG) lasers in the treatment of nevus of Ota. STUDY DESIGN/MATERIALS AND METHODS: Thirty-three patients (11 male, 22 female) were recruited for this study, and 45 treatment sessions were performed. Half of each lesion was treated with QS Alex and the other half with QS Nd:YAG laser. Patients were interviewed with a visual analog scale questionnaire immediately after treatment and 1 week later. Questions included the degree of pain, swelling, and bleeding. RESULTS: The immediate pain after treatment was more severe for QS Alex than for QS Nd:YAG laser. However, 1 week after laser therapy, most patients found QS Alex to be superior. CONCLUSION: Patients tolerate QS-Alex better than QS Nd:YAG. This finding is important because patients with nevus of Ota are often children, and multiple laser sessions are necessary for complete resolution of the lesion.

Activities of Daily Living↗

PubMed1998

Burn injuries during paint thinner sniffing.

Thinner sniffing is popular among school children in Asian countries because it is readily available at low cost. Besides its toxicity to major organs, thinner inhalation is associated with various burn accidents. Four teenagers were admitted to the Burns Unit of the Prince of Wales Hospital over the period of 1996-1997. They sustained 3-25% TBSA flame burn and two of them had inhalation injuries as a result of the ignition of a cigarette during thinner sniffing. None of them had evidence of thinner intoxication as shown by blood tests. In the management of their acute burn injuries, their hidden social and family problems were explored. With the cooperation of different disciplines, early psychosocial intervention was given and their behavioral and psychological disturbances were successfully managed.

Adolescent↗

PubMed1998

Single-dose tropisetron for preventing postoperative nausea and vomiting after breast surgery.

UNLABELLED: In this randomized, double-blind, placebo-controlled study, we compared the efficacy of tropisetron 5 mg with tropisetron 2 mg for the prevention of postoperative nausea and vomiting (PONV) after breast surgery. One hundred forty-eight female patients were randomized to receive either tropisetron 5 mg (n = 49), tropisetron 2 mg (n = 49), or saline (n = 50) before the induction of anesthesia with thiopental and morphine. Anesthesia was maintained with nitrous oxide and isoflurane. Postoperative analgesia was provided by patient-controlled analgesia with i.v. morphine. The incidence of PONV, the pain score, and the analgesic requirement were recorded for 48 h. There was no difference among groups in patient characteristics, risk factors for PONV, morphine consumption, or side effects. During the first 6 h postoperatively, the incidence of PONV after tropisetron 2 mg and 5 mg were similar and were superior to placebo (P < 0.001). After 6 h, the incidence of PONV increased significantly in patients who had received tropisetron 2 mg (P = 0.01) and was greater than that in patients who had received tropisetron 5 mg (P = 0.001). We conclude that single-dose tropisetron 5 mg is more effective than tropisetron 2 mg in the prevention of PONV after breast surgery. IMPLICATIONS: Breast surgery is associated with a high incidence of postoperative nausea and vomiting. A single dose of i.v. tropisetron 5 mg is well tolerated and decreases the number of vomiting and nausea episodes after surgery.

Adolescent↗

PubMed1997

Evaluation of artificial skin (Integra) in a rodent model.

The biocompatibility of artificial skin (Integra) has been investigated in clean surgical wounds of 20 guinea-pigs. A rectangular 3 x 3 cm full-thickness skin defect with excision carried down to the panniculus carnosus was prepared on the dorsal area of the guinea-pig. A thin layer of silver sulfadiazine cream was applied and artificial skin was placed to cover the wound. At day 14, the uppermost silicone layer was removed. Good take of the artificial skin was observed in 18 of 20 animals. Microscopy showed good vascular ingrowth in 14 of the 18 animals. The remaining four animals showed necrotic tissue, absence of vascularization and haemorrhage in the wound bed. Two of the 20 wounds showed purulent discharge. In this animal model, clinical 'take' of the neodermis was achieved in 18/20 animals (90 per cent), while vascular ingrowth was observed in only 14/20 animals (70 per cent). These results suggested that artificial skin in clean surgical wound is readily biologically incorporated into surrounding viable tissue.

Animals↗