Search PubMed⌕ Search

Biomedical subjects

J G Wong

Publications and source records attributed to J G Wong.

At least 19 recordsLinked to original sources
PubMed2003

A practical guide to capacity assessment and patient consent in Hong Kong.

A person's decision-making capacity is pivotal when a doctor determines whether a person has the ability to make his or her own decisions, and thus it has major clinical, ethical, and legal significance, especially in Hong Kong, where the Mental Health Ordinance has introduced Guardianship provisions and provisions for the treatment of mentally incapacitated persons. This paper examines the legal concept of decision-making capacity and its clinical assessment within the local context. It is important for doctors to be aware of the legal mechanisms under which both urgent and non-urgent treatment can be given to mentally incapacitated persons, provided that the treatment is necessary and given in the best interests of the patient.

Adult↗
PubMed2001

Effects of triamcinolone acetonide on microglial morphology and quantitative expression of MHC-II in exudative age-related macular degeneration.

Animal models, in vitro assays and pilot clinical studies suggest that intravitreal triamcinolone acetonide may be useful in the treatment of age-related macular degeneration. The present case study reports the effect of intravitreal triamcinolone acetonide injection on a subretinal neovascular lesion, microglial morphology and quantitative expression of MHC-II antigens. Triamcinolone acetonide significantly decreased MHC-II expression consistent with immunocytochemical observations which revealed condensed microglial morphology. The modulation of subretinal oedema and microglial morphology correlates with in vitro observations suggesting that downregulation of inflammatory markers and endothelial cell permeability are significant features of the mode of action of triamcinolone acetonide.

Aged↗
PubMed2001

Genetic discrimination and mental illness: a case report.

With advances in genetic technology, there are increasing concerns about the way in which genetic information may be abused, particularly in people at increased genetic risk of developing certain disorders. In a recent case in Hong Kong, the court ruled that it was unlawful for the civil service to discriminate in employment, for the sake of public safety, against people with a family history of mental illness. The plaintiffs showed no signs of any mental health problems and no genetic testing was performed. This was the first case concerning genetic discrimination in common law jurisdictions, therefore the court's judgment has implications for how genetic discrimination cases may be considered in the future. The court considered it inappropriate to apply population statistics or lifetime risks to individuals while examining fitness for work. It recommended an individualised assessment of specific risks within the job, relative to other risks posed by that workplace.

Adult↗
PubMed2001

The synchronisation of signal emission with wingbeat during the approach phase in soprano pipistrelles (Pipistrellus pygmaeus).

Previous studies have shown that, during search flight in bats, wingbeat, respiration and echolocation are synchronised in a 1:1 relationship. An efficiently integrated locomotor-respiratory system enables bats to produce intense echolocation signals at little or no cost above that required for flight. In this study, we investigated the coupling of wingbeat with echolocation in the laboratory during approach flight in soprano pipistrelles (Pipistrellus pygmaeus) using high-speed digital video at 250 and 500 frames s(-)(1). We found that soprano pipistrelles most commonly produce single or double pulses per wingbeat. Single pulses per wingbeat occurred in two alternative positions: immediately before the end of the upstroke or after the start of the downstroke. Double pulses per wingbeat were emitted in the same wingbeat positions on the upstroke and the downstroke, as in single pulses per wingbeat. We suggest that, during approach flight, the coupling of more than one echolocation signal with a single wingbeat and expiratory cycle allows echolocation to remain energetically economic. When soprano pipistrelles approached a Perspex disc target, an increase in mean repetition rate was achieved by producing an extra pulse per wingbeat. Finally, we hypothesise that the bat's approach to potentially interesting targets in the same horizontal plane as it's flight path, i.e. during flapping flight, may be characterised by the production of double pulses per wingbeat, resulting in a unique pattern of echolocation pulse intervals.

Animals↗
PubMed2000

The capacity of people with a 'mental disability' to make a health care decision.

BACKGROUND: Based on the developing clinical and legal literature, and using the framework adopted in draft legislation, capacity to make a valid decision about a clinically required blood test was investigated in three groups of people with a 'mental disability' (i.e. mental illness (chronic schizophrenia), 'learning disability' ('mental retardation', or intellectual or developmental disability), or, dementia) and a fourth, comparison group. METHODS: The three 'mental disability' groups (N = 20 in the 'learning disability' group, N = 21 in each of the other two groups) were recruited through the relevant local clinical services; and through a phlebotomy clinic for the 'general population' comparison group (N = 20). The decision-making task was progressively simplified by presenting the relevant information as separate elements and modifying the assessment of capacity so that responding became gradually less dependent on expressive verbal ability. RESULTS: Compared with the 'general population' group, capacity to make the particular decision was significantly more impaired in the 'learning disability' and 'dementia' groups. Importantly, however, it was not more impaired among the 'mental illness' group. All the groups benefited as the decision-making task was simplified, but at different stages. In each of the 'mental disability' groups, one participant benefited only when responding did not require any expensive verbal ability. CONCLUSIONS: Consistent with current views, capacity reflected an interaction between the decision-maker and the demands of the decision-making task. The findings have implications for the way in which decisions about health care interventions are sought from people with a 'mental disability'. The methodology may be extended to assess capacity to make other legally-significant decisions.

Adolescent↗
PubMed1999

The rational clinical examination. Does this adult patient have acute meningitis?

CONTEXT: Early clinical recognition of meningitis is imperative to allow clinicians to efficiently complete further tests and initiate appropriate therapy. OBJECTIVE: To review the accuracy and precision of the clinical examination in the diagnosis of adult meningitis. DATA SOURCES: A comprehensive review of English- and French-language literature was conducted by searching MEDLINE for 1966 to July 1997, using a structured search strategy. Additional references were identified by reviewing reference lists of pertinent articles. STUDY SELECTION: The search yielded 139 potentially relevant studies, which were reviewed by the first author. Studies were included if they described the clinical examination in the diagnosis of objectively confirmed bacterial or viral meningitis. Studies were excluded if they enrolled predominantly children or immunocompromised adults or focused only on metastatic meningitis or meningitis of a single microbial origin. A total of 10 studies met the criteria and were included in the analysis. DATA EXTRACTION: Validity of the studies was assessed by a critical appraisal of several components of the study design. These components included an assessment of the reference standard used to diagnose meningitis (lumbar puncture or autopsy), the completeness of patient ascertainment, and whether the clinical examination was described in sufficient detail to be reproducible. DATA SYNTHESIS: Individual items of the clinical history have low accuracy for the diagnosis of meningitis in adults (pooled sensitivity for headache, 50% [95% confidence interval [CI], 32%-68%]; for nausea/vomiting, 30% [95% CI, 22%-38%]). On physical examination, the absence of fever, neck stiffness, and altered mental status effectively eliminates meningitis (sensitivity, 99%-100% for the presence of 1 of these findings). Of the classic signs of meningeal irritation, only 1 study has assessed Kernig sign; no studies subsequent to the original report have evaluated Brudzinski sign. Among patients with fever and headache, jolt accentuation of headache is a useful adjunctive maneuver, with a sensitivity of 100%, specificity of 54%, positive likelihood ratio of 2.2, and negative likelihood ratio of 0 for the diagnosis of meningitis. CONCLUSIONS: Among adults with a clinical presentation that is low risk for meningitis, the clinical examination aids in excluding the diagnosis. However, given the seriousness of this infection, clinicians frequently need to proceed directly to lumbar puncture in high-risk patients. Many of the signs and symptoms of meningitis have been inadequately studied, and further prospective research is needed.

Acute Disease↗
PubMed1999

Capacity to make health care decisions: its importance in clinical practice.

BACKGROUND: Assessment of capacity plays a pivotal role in determining when decisions need to be made on behalf of an individual. It therefore has major clinical management implications for health care professionals and civil liberties implications for the person concerned. In many countries, there is a presumption that adults have the capacity to make health care decisions. However, in persons with a mental disability, capacity may be temporarily or permanently impaired. METHODS: A selective review is presented which considers: (i) the broad approaches taken to determining capacity; (ii) the abilities commonly assessed in determining capacity; and (iii) the principles underlying health care decision-making for adults who are without capacity. RESULTS: Capacity is a functional concept, determined by the person's ability to understand, retain, and weigh up information relevant to the decision in order to arrive at a choice, and then to communicate that choice. We have reviewed the studies that examined decision-making abilities in people with dementia, chronic mental illness or intellectual disabilities. Approaches to decision-making in adults who lack capacity include: anticipatory decisions made through advance health care statements or decisions by proxy based on 'best interests' or 'substituted judgement'. CONCLUSIONS: The understanding of clinical and legal aspects of capacity is still developing. This paper examines current concepts of capacity and decision-making on behalf of those without capacity. We propose a framework, in line with current ethical and legal guidelines, as an aid to clinicians when they are seeking consent for a health care intervention.

Adult↗