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Biomedical subjects

K M Chan

Publications and source records attributed to K M Chan.

At least 127 records · Page 7Linked to original sources
PubMed1998

Determinants of axial and peripheral bone mass in Chinese adolescents.

OBJECTIVE: To determine the relation of puberty, physical activity, physical fitness, and calcium intake with bone mineral content (BMC) of the distal radius, and on bone mineral density (BMD) of the L2 to L4 vertebrae in a group of healthy Chinese adolescents. DESIGN: Cross sectional survey. SUBJECTS: A group of 179 healthy Chinese adolescents (92 boys and 87 girls) aged 12 to 13 years enrolled in the first year of the Tii Junior High School in Shatin, Hong Kong. Ninety four of the pupils enrolled were in the physical education major class (PE), and the other 85 were in the art major class (ARTS). MAIN OUTCOME MEASURES: Correlation of BMC of the distal radius and BMD of the L2 to L4 vertebrae with level of physical activity, physical fitness (isometric and isokinetic), muscle strength of the upper and lower limb, and calcium intake. RESULTS: BMC of the distal radius and BMD of the L2 to L4 vertebrae were significantly positively correlated. Univariate and regression analysis showed that age, pubertal staging, physical fitness, and muscle strength were significantly associated with bone mass in a positive way. Calcium intake and type of sport practised did not exert a significant influence on BMC of the distal radius and BMD of the L2 to L4 vertebrae in boys. The results for the BMD of the L2 to L4 vertebrae were similar in girls and boys; however, in girls, the BMC of the distal radius had a negative correlation with calcium intake. Physical fitness was a significant positive predictor of BMD of the L2 to L4 vertebrae. CONCLUSIONS: Among Chinese adolescents bone mass was positively influenced by certain measures of physical fitness as well as by age, weight, and pubertal stage.

Adolescent↗
PubMed1998

The prescribing pattern of hospital doctors.

OBJECTIVE: There has been no local data on the prescribing habits of doctors over the last 25 years. This is a retrospective study done to examine the outpatient prescribing pattern of doctors at Alexandra Hospital over a one month period in 1995. METHOD: Six-thousand five-hundred and three scripts were analysed. A total of 16,642 items were prescribed. The distribution of prescription scripts by departments included Accident & Emergency 39.0%; Medical 23.5%; Orthopaedics 10.3%; Surgery 18.5%; Paediatrics 4.4%, and Geriatrics 4.3%. The overall mean number of drugs prescribed was 2.6 (median = 2, mode = 2, range = 14). RESULTS: Analysis of the overall results by age groups showed the following means for "total number of drugs prescribed": (> 0 to 20 years) = 2.23, (> 20 to 40 years) = 2.42, (> 40 to 60 years) = 2.61 and (> 60 years) = 3.18. Analysis of variance showed highly significant results between the means of each age-group. Post-hoc analysis revealed that the oldest age group (> 60 years) accounted for most of this significant result. The top 10 drugs used by the hospital were (in descending order): NSAIDs, antacids, analgesics (other than NSAID), antibiotics, topical medications, anti-diarrhoeal agents, anti-histamines, vitamins, anti-emetics and promethazine cough syrup. There was a high usage of NSAID-antacid combination. Similarly, amoxycillin was often given with cloxacillin. There was an underuse of anti-depressants. There were very few (0.15%) illegible prescriptions. Only one prescription had an adverse combination of drugs. CONCLUSION: This is the first local study of prescribing pattern of a hospital. While this data may vary from hospital to hospital, depending on the patient mix, it does provide some useful baseline data which hitherto never existed. Our findings suggested that the elderly do receive more medications.

Adolescent↗
PubMed1998

Knee injuries produced by recreational sports follow a different pattern than casual injuries.

Data was collected on 208 Chinese males who underwent knee arthroscopy following trauma in the period from January 1993 through December 1994. For the purpose of comparison and analysis, the patients were classified according to their sporting habits as sedentary patients, recreational athletes, or competitive athletes. There were no significant differences in age between the three groups (average age: 25.82 +/- 10.6; range: 12 to 73 years). A hemarthrosis was present in 122 patients, and an effusion in 35. The most common mechanism of injury was direct impact (105 patients), followed by a twisting injury (58 patients). The most common arthroscopic finding was an anterior cruciate ligament (ACL) tear (partial in-37 patients and complete in 43 patients). In both sedentary and athletic patients, a hemarthrosis was significantly associated with ACL and meniscal tears (p = 0.02). When comparing the pattern of arthroscopic pathology between sports and casual injuries, a significantly greater number of ACL tears (both complete and partial) were caused during sports activity (p = 0.032). Sports injuries also resulted in a significantly greater number of meniscal injuries (p = 0.028). However, sedentary patients suffered from a greater prevalence of tibial osteochondral fractures (10%) than did those in the sports group (5%) (p = 0.04).

Adolescent↗
PubMed1998

Self-perception of health among elderly community dwellers in Singapore.

Majority (90.5%) of the elderly living in the community in Singapore had a positive (satisfactory to good) perception of their health. This study found that age (70 years or older), recent hospitalisation, regular medical follow-up, hearing impairment, presence of chronic medical conditions (like musculo-skeletal problems, hypertension, ischaemic heart disease and chronic obstructive lung disease), impairment in activities of daily living, history of falls, those on regular medications and those with financial difficulties all adversely influenced perception of health. Those able to participate in regular outdoor leisure activities have a positive influence. Factors that did not significantly influence perception of health were gender, health-promoting activities, work, poor eyesight, cognitive impairment, urinary incontinence, diabetes, history of stroke and the ability to use public transport.

Activities of Daily Living↗
PubMed1998

Day hospital rehabilitation for the elderly: a retrospective study.

Alexandra Hospital has the first day hospital for rehabilitation of the elderly in Singapore. To determine if functional skills and mobility improved significantly with a Day Hospital rehabilitation programme, and the factors influencing the outcome, a pre-test/post-test study was conducted on 30 male and 34 female patients discharged from the programme between 1 October 1995 and 30 June 1996. The Barthel Index was used to assess functional status and the Elderly Mobility Scale was used to assess mobility. All patients were assessed by trained therapists and scored on admission to and at discharge from the programme. We found a significant difference in the mean Barthel Index scores of 59.7 (SD 18.7) on admission and 71.4 (SD 20.5) at discharge (P < 0.001). The difference in the mean Elderly Mobility Scale of 7.1 (SD 4.3) on admission and 11.8 (SD 4.7) at discharge was also significant (P < 0.001). Improvement in functional skills and mobility were both inversely correlated with age. Multiple linear regression analysis showed that age and Barthel Index on admission were significant independent determinants of the Barthel Index at discharge, while age, Barthel Index and Elderly Mobility Score on admission significantly determined the Elderly Mobility Scale at discharge. This study showed that functional skills and mobility improved with rehabilitation in the elderly population, but younger and less severely disabled individuals tended to fare better.

Activities of Daily Living↗
PubMed1998

Nursing home applications--reasons and possible interventions.

BACKGROUND: With a rapidly ageing population like Singapore, the need for nursing homes will increase. Admission to a nursing home may be for medical and/or social reasons. We carried out case studies with the Care Liaison Service (CLS) of the Ministry of Health to determine reasons why the elderly applied for nursing home admission, and whether it was possible to prevent an admission. PATIENTS: During the 6-month study period, 331 applications were received, of which 280 (84.6%) were > or = 60 years. There was an equal distribution of male (50.4%) and female (49.6%) applicants. Applicants were predominantly Chinese (86.0%), followed by Indians (8.0%), Malays and other races (3.0% each). Most of the applicants were semi-ambulant (50.0%), fully ambulant (31.4%) and non-ambulant (18.6%). The most common medical problems of the applicants were neurological (e.g. stroke, normal pressure hydrocephalus, epilepsy), heart diseases (e.g. hypertension, ischaemic heart disease, heart failure), orthopaedic conditions (e.g. osteoarthritis, fractures neck of femur and other fractures), and psychiatric problems (e.g. dementia, depression and history of schizophrenia/paranoid psychosis). METHOD: Fifty-seven applicants (20.4%) were selected for intervention. They were 'non-psychiatric' patients whose caregivers were willing but unable to look after them. About half (28, 49.1%) of these applicants required nursing home care. The remaining 29 patients (50.9%) had the potential of improving or able to remain at home with appropriate community services. These 29 patients were contacted by the CLS nurse and the following recommendations were made: 1) inpatient rehabilitation in a community hospital (7 patients); 2) rehabilitation and day care in a community-based day care centre (17 patients); 3) domiciliary medical care (4 patients), and 4) reassessment by psychiatrist to control psychotic symptoms (1 patient). Only 6 patients were willing to accept the new recommendations. This poor result may imply that attempts at intervention at this stage may be too late. CONCLUSION: We need to identify the group at risk for nursing home admissions early, take a proactive stance towards them, increase support to their caregivers to prevent burnt-out and continue to develop and publicize community-based services. More studies need to be done in this area.

Aged↗
PubMed1998

Care of elderly patients with DNR orders in Singapore--a descriptive study.

OBJECTIVE: To describe the demographic profile of a cohort of elderly patients with a 'do-not-resuscitate' (DNR) order at death and to study the specific supportive measures instituted or withdrawn during the DNR period and those in force at the time of death. METHODS: The case notes of patients who died between October 1996 and March 1997 in the Department of Geriatrics, Alexandra Hospital were studied retrospectively by a single observer. RESULTS: Only 95 out of an eligible 102 patients' case notes could be retrieved. Seventy-two (75.8%) patients had a DNR status at death. The racial distribution was as follows: 90.3% Chinese, 5.6% Indians, 2.8% Malays and 1.4% Others while their pre-admission domicile were: own home 79.2%, nursing home 19.4% others 1.4%. Those bedbound constituted 48.6% of the cohort while 29.2% had dementia and 43.1% were totally dependent for their activities of daily living. The commonest cause of death was pneumonia while the average duration patients were on the DNR status was 5.1 days before death. The commonest measures instituted during DNR period were as follows: oxygen therapy (38.9%), nasogastric tube insertion and feeding (30.6% and 33.3% respectively), intravenous fluid administration (33.3%), blood investigations (33.3%), opioid use (33.3%) and antibiotic use (29.2%). Measures withdrawn were intravenous fluid administration (36.1%), hourly monitoring of parameters (22.2%), antibiotics (13.9%), high dependency care (12.5%) and nasogastric tube feeding (6.9%). CONCLUSION: The DNR status is decided late in the course of a patient's illness when he may have been too ill to partake in the decision making process. Even if a DNR status was ordered, a patient might still be subjected to CPR at death.

Aged↗
PubMed1997

Characterization of rainbow trout (Oncorhynchus mykiss) growth hormone 1 gene and the promoter region of growth hormone 2 gene.

Studies by Agellon et al. (Mol. Reprod. Dev. 1, 11-17) showed the presence of two growth hormone (rtGH1 and rtGH2) mRNA species in pituitary glands of adult rainbow trout (Oncorhynchus mykiss). In this study, we have detected rtGH1 and rtGH2 mRNAs in pituitary glands of rainbow trout from fry to 2 years of age. The level of rtGH1 mRNA is notably higher than that of rtGH2 mRNA in 10-day-old fry and 2-year-old females. These results suggest differential expression of rtGH1 and rtGH2 genes in different sexes and developmental stages. As a step toward elucidating the mechanism of differential expression of both GH genes, DNA fragments encoding rtGH1 gene and the promoter/regulatory region of rtGH2 gene were isolated and characterized. Rainbow trout GH genes span approximately 4.5 kb and are composed of six exons and five introns. The 5'-flanking region of both genes contain consensus sequences for TATA boxes and several Pit-1 binding sequences. Consensus sequences related to the cAMP response element, thyroid hormone response element, retinoic acid response element, estrogen response element (ERE), and glucocorticoid response element are present not only in the 5'-flanking region, but also in introns and exons in rtGH1 gene. These hormone response elements, except ERE, are also present in rtGH2 gene.

Animals↗
PubMed1997

Sequence of a cDNA clone encoding a novel somatolactin in goldfish, Carassius auratus.

As a first step towards the development of a sensitive ribonuclease protection assay to study the regulation of somatolactin (SL) mRNA expression in pituitary cells of goldfish, we have isolated a complementary DNA (cDNA) clone encoding precursor sequence of SL from a cDNA library prepared from goldfish pituitary poly(A)+ RNA. The 843-bp goldfish SL (gfSL) cDNA has an open reading frame of 693 nucleotides with two possible start codons of AUG. Amino acid sequence alignment revealed that gfSL has the characteristics of four conserved domains (A, B, C and D) common to all SLs with the domain B being the most conserved region among all the characterized SLs. Similar to other teleost SLs, this gfSL is similarly related but clearly distinct from growth hormone and prolactin of goldfish and other teleosts. However, unlike most other known teleost SLs which have more than 70% amino acid sequence identity to each other, the overall amino acid sequence identity of this novel gfSL with other previously characterized SLs ranges from only 36% to 51%. Moreover, this gfSL contains only six cysteine residues, rather than seven in most other SLs, in conserved positions. Northern blot analysis revealed a single gfSL mRNA transcript of approximately 1 kb in the pituitaries of both sexually regressed and maturing male and female goldfish.

Amino Acid Sequence↗
PubMed1997

Stabilization of osteochondral fractures: an experimental study comparing polyglycollic acid degradable pin with K-wire stabilization in rabbits.

Conventional metal implants may be unsuitable for the stabilization of osteochondral fractures as they may interfere with joint function and eventually require implant removal. We therefore compared the use of biodegradable implants with conventional metal ones in an animal experimental study conducted in skeletally mature rabbits. Biodegradable polyglycollic acids pins (PGA) 1.5 mm in diameter were used to stabilize an osteochondral fragment surgically created in the distal femur of rabbits. In another group of 36 animals, conventional metal K-wire of the same diameter was used for stabilization. The animals were killed at intervals of 3 to 24 weeks. Satisfactory union of the fragments was noted in 92% of the PGA implants as compared with 50% with the metal implants group. No implant migration was seen in the PGA group, while migration was noted in all animals with the metal implants. Histological studies showed that in 80% of the cases fixed with PGA implants, the fragment was viable. In the metal group 33% of the fragments underwent fragmentation and necrosis.

Animals↗
PubMed1997

Electrical stimulation prevents immobilization atrophy in skeletal muscle of rabbits.

OBJECTIVE: To investigate the effect of unilateral cast immobilization with and without surface electrical stimulation (ES) on the tibialis anterior (TA) muscle of rabbits. DESIGN: Prospective randomized trial. SETTING: University medical school. ANIMALS: 53 New Zealand White rabbits (aged 54 to 63 days, weight 1.73 to 1.91 kg). METHODS AND INTERVENTION: Random assignment, for a 3-week period, to one of four groups: C group (control group), I group (immobilization group), S group (group of electrical stimulation which was stimulated isometrically at 50 Hz, 30 minutes per day, 5 times a week), and IS group (immobilization group which, like the S-group, received electrical stimulation). OUTCOME MEASURES: Muscle wet wight, muscle fiber cross-sectional area, muscle fiber types, and muscle capillary supply. RESULTS: Muscle wet weight decreased significantly in the I group by 19% (p < or = .05), with a corresponding significant reduction in the total muscle fiber cross-sectional area of 26% (p < or = .05). No significant changes were observed in muscle wet weight and muscle fiber cross-sectional area in the S and IS groups. Interstitial fibrosis was observed in the I group and occasionally in the IS group. No significant changes in the total number of muscle fiber types I and II were found in all experimental groups. The capillary supply of the S and IS groups did not change significantly. However, capillary-to-fiber ratio was significantly reduced by 20% with a simultaneously nonsignificant increase in capillary density (capillaries/mm2) of 11% (p > .05) in the I group. Furthermore, muscle fiber regeneration was observed predominantly in the I group. CONCLUSIONS: In this experimental model, ES effectively prevented immobilization-induced muscle atrophy by minimizing reduction of muscle fiber cross-sectional area, interstitial fibrosis, and impaired blood supply.

Animals↗
PubMed1997

Pulsed magnetic and electromagnetic fields in experimental achilles tendonitis in the rat: a prospective randomized study.

OBJECTIVE: To investigate the effects of pulsed magnetic fields (PMF) and pulsed electromagnetic fields (PEMF) on healing in experimental Achilles tendon inflammation in the rat. DESIGN: Prospective randomized trial. SETTING: University medical school. METHODS: Exposure of the Achilles tendon and injury by a weight of 98.24 g falling from a height of 35cm in 180 male Sprague-Dawley rats. INTERVENTION: A daily 15-minute session with PMF of 17Hz or 50Hz, or PEMF of 15Hz or 46Hz, or a sham session. OUTCOME MEASURES: Random sacrifice 2 hours after the operation, and at 1, 3, 7, 14, or 28 days. Assessment of water content, weight, and histological appearance of the tendons. RESULTS: The time from injury and the various treatment modalities exerted a significant influence on the water content of the tendon after the injury (two-way ANOVA, p = .02). At day 3, the water content of the PEMF 46Hz group was significantly higher than in the other groups, decreasing sharply by day 7, and being similar to the other groups thereafter. By the end of the experiment, the PEMF 15Hz group was not significantly different from the control group. At day 7, the PMF 50Hz group showed significantly lower water content than the control group (p = .03), but at 14 days the PMF 50Hz group was not significantly different from the control group. PMF 50Hz suppressed the extravascular edema during early inflammation. PMF 17Hz showed a similar initial trend, producing a consistent lower water content throughout the experiment, reaching statistical significance by the end of treatment. By the end of the experiment, the collagen fibers had nearly regained their normal alignment in all groups, with a more physiological alignment seen in the PEMF 17Hz group. CONCLUSIONS: The tendon returned to histological normality in all groups, but the PMF 17Hz group showed better collagen alignment by the end of the study. PMF 17Hz resulted in a greater reduction of inflammation, with a better return of the tendon to histological normality. Different PMF and PEMF could be applied according to when treatment is started after the injury. If there is no delay between injury and beginning of pulsed magnetic treatment, PMF 17 should be used.

Achilles Tendon↗
PubMed1997

Effect of arsenite, arsenate, and the herbicide monosodium methyl arsonate (MSMA) on hepatic metallothionein expression and lipid peroxidation in channel catfish.

Arsenic exerts its toxicity by the generation of reactive oxygen intermediates which caused lipid peroxidation and cellular damage. Metallothioneins (MTs) have been shown to be induced by oxidative stress and act as scavengers of reactive oxygen intermediates. Thus, hepatic MT was examined in channel catfish treated with the herbicide monosodium methyl arsonate (MSMA) and compared to equal doses of trivalent and pentavalent arsenic. Fish were exposed to 0.01, 0.1, and 1.0 mg/L of each compound for 1 week by static renewal. Hepatic MT was measured by the cadmium/hemoglobin (Cd/Hb) saturation assay, ELISA using antibodies raised against the first 10 amino acids of piscine MT, and Northern blot analysis using a cDNA encoding winter flounder hepatic MT. Cd/Hb and ELISA measurements of low molecular weight fractions from the hepatic cytosolic component of fish exposed to MSMA revealed a dose dependent increase in MT. MTs and MT mRNA of fish receiving the 1.0 mg/L dose were significantly induced vs control. Responses to arsenate exposure were more variable, but showed a trend toward a dose-dependent induction of MT and MT mRNA. MT mRNA and protein also showed a dose-dependent increase with arsenite exposure with no significant differences with untreated animals. Hepatic lipid peroxidation (as determined by TBARS) and glutathione was unaltered by any of the arsenical treatments. Thus, the lack of correlation between oxidative stress and MT expression suggest MT may not be a reliable indicator of oxidative stress. In addition, the induction of hepatic MT by various forms of As does not appear to be mediated through an oxidative stress mechanism in the liver.

Animals↗
PubMed1997

Knee arthroscopy in Chinese children and adolescents: an eight-year prospective study.

In the period January 1985 to December 1992, 69 Chinese boys and 20 Chinese girls (average 14.6 years, age range 6 to 16 years) with a total of 92 involved knees underwent examination under anaesthesia and knee arthroscopy. Two thirds of the patients were engaged in sports activities. A haemarthrosis was present in 51 patients. In one patient, Staphylococcus aureus was shown, and in two children a serous-purulent aspirate grew Mycobacterium tuberculosis. The lateral meniscus was torn in four knees and the medial meniscus in six. An intact discoid lateral meniscus was found in five girls. Three partial anterior cruciate ligament (ACL) tears, three complete ACL tears and two posterior cruciate ligament tears were diagnosed. One child had an osteochondral defect of the lateral femoral condyle accompanying an ACL and a lateral meniscal tear. Nonspecific synovitis of unknown etiology was diagnosed in six patients who had presented subacutely with at least a 2-month history of a symptomatic monoarticular knee effusion with low grade local inflammation and no history of major trauma. The synovitis gradually resolved over a 6- to 10-month period after arthroscopy. Knee arthroscopy in children and adolescent patients is safe, gives a high diagnostic accuracy, and allows treatment of a variety of intraarticular conditions. This study also demonstrates that the range of intraarticular knee problems found in Chinese children and adolescents differs from that described in their Western counterparts.

Adolescent↗
PubMed1997

Experience with primary exeter total hip arthroplasty in patients with small femurs. Review at average follow-up period of 6 years.

One hundred twelve hips in 101 Chinese patients received a primary cemented Exeter total hip arthroplasty (Howmedica, Hong Kong). Average age was 65 years. The most common diagnosis was avascular necrosis. Average follow-up period was 6 years (range, 3 years to 9 years, 6 months). The Harris hip score improved from a preoperative average of 41.2 to 82.2 at the last follow-up visit. Stem subsidence within the cement mantle occurred in 9% of the cases, and none of these stems had other evidence of loosening. Three hips in two patients were revised because of loosening at 5 to 8 years after surgery. Because of the small size of the femurs, stem oversizing was common. Oversizing of the stem and an incomplete cement mantle might account for the early loosening. Stems of a smaller size should be made available to this population.

Adult↗
PubMed1997

Osteonecrosis of the femoral head treated with cementless total hip arthroplasty. A comparison with other diagnoses.

Primary cementless Porous Coated Anatomic total hip arthroplasty was carried out in 36 hips in 29 patients with osteonecrosis (ON) patients and in 36 hips in 33 patients without ON. The ON was alcohol related in 11. steroid induced in 5, post-traumatic in 4, and idiopathic in 16 patients. The average follow-up period was 6 years. Clinical evaluation demonstrated 77.8% excellent or good results in the patients with ON, with the average Harris hip scores improved from 36.8 to 83.5. No revision of a prosthesis has yet been performed in the patients with ON. The patients with alcohol-related and steroid-induced ON had inferior clinical results when compared with the patients without ON. There were no statistically significant differences in the clinical results between the patients with post-traumatic or idiopathic ON and the patients without ON.

Adult↗