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Y F Chan

Publications and source records attributed to Y F Chan.

At least 19 recordsLinked to original sources
PubMed2006

A novel carbon nanotube structure formed in ultra-long nanochannels of anodic aluminum oxide templates.

We report the fabrication of a novel carbon structure consisting of uniform carbon nanotubes formed in the nanochannels of anodic aluminum oxide (AAO) templates, with the surface side open and connected by a uniform carbon sheet. The uniformity of the fabricated CNT arrays, plus the carbon film on the AAO surface interconnecting the open ends of all CNTs, constitute the major characteristics unique to our carbon structures. Some potential applications of such structures are noted.

Journal Article↗
PubMed2005

Massive myocardial calcification in second-trimester fetuses: antenatal detection and causes.

Massive myocardial calcifications were detected by antenatal ultrasound examination in four second-trimester fetuses. In one fetus, multiple cardiac rhabdomyomas were the initial diagnosis. One fetus presented with arthrogryposis and the brain and spinal cord showed severe hypoxic-ischemic damage. One fetus was hydropic and had severe cardiac malformations. The fourth fetus had congenital heart block and maternal serum was positive for anti-Ro and anti-La antibodies. Myocardial calcifications in the first three fetuses were most likely to be caused by hypoxic-ischemic damage to the heart, and immunological mechanisms were responsible in the other fetus. Antenatally detected myocardial echogenic foci in a fetus leading to a termination of pregnancy or associated with fetal death should be investigated with a full postmortem examination. It is important to confirm the presence of calcifications as distinct from a rhabdomyoma as genetic counseling is completely different. The demonstration of associated lesions in other organs also helps to explain the pathogenesis underlying this condition.

Adult↗
PubMed2005

Transcatheter embolisation of visceral pseudoaneurysms--technical difficulties and modification of embolisation technique.

We report 13 successful emergency embolisations for 12 pseudoaneurysms performed in 10 patients. For five pseudoaneurysms the embolisation technique was modified according to number of supplying vessels, flow rate of pseudoaneurysms, vascular anatomy and whether there was clinical evidence of re-bleeding or not. Apart from traditional embolisation technique, modified embolisation techniques are also useful for endovascular therapy of pseudoaneurysms.

Adult↗
PubMed2005

Predictive value of the user seal check in determining half-face respirator fit.

Guidelines issued by the Centers for Disease Control and Prevention and the World Health Organization state that healthcare workers should wear N95 masks or higher-level protection during all contact with suspected cases of severe acute respiratory syndrome. Before use, the manufacturer recommends performing a user seal check to ensure that the mask is fitted correctly. This study aimed to test the ability of the user seal check to detect poorly fitting masks. This study is a retrospective review of a mask-fitting programme carried out in the intensive care unit of the Prince of Wales Hospital in Hong Kong. In this programme, all staff were tested with two types of N95 mask and one type of N100 mask. The results of the documented user seal check were then compared with the formal fit-test results from a PortaCount. Using a PortaCount reading of 100 as the criterion for a correctly fitted mask, the user seal check wrongly indicated that the mask fitted on 18-31% of occasions, and wrongly indicated that it did not fit on 21-40% of occasions. These data indicate that the user seal check should not be used as a surrogate fit test. Its usefulness as a pre-use test must also be questioned.

Female↗
PubMed2005

Virucidal activity of Virkon S on human enterovirus.

The efficacy of Virkon S, a commercial disinfectant as a virucidal spray against human enterovirus 71 (HEV71), the causative agent of the fatal form of hand, foot and mouth disease was examined. At least one log10 reduction of HEV71 titer was achieved when one spray of Virkon (1% or 2%) with ten minutes of contact time was applied. The infectivity was completely lost when four sprays of 1% or 2% Virkon were applied, suggesting that at least four sprays of 1% Virkon to the surface bound HEV71 was necessary to completely inactivate the virus. These findings suggest that Virkon S at the proper concentration is suitable to be used as an effective and easy to use disinfectant against HEV71.

Administration, Topical↗
PubMed2000

Pleuropulmonary blastoma: four cases.

Pleuropulmonary blastoma (PPB) is a rare malignant neoplasm affecting children. A retrospective review was carried out of patients diagnosed as having PPB at one institute over a period of 16 years. The presentation, diagnosis, treatment, and family history were studied. PPB usually presents with symptoms and signs of respiratory tract infection, and the diagnosis may be delayed. There are no distinguishing clinical features or imaging studies. The diagnosis is made on histologic examination of tumour material and is sometimes difficult to differentiate from benign cystic lung lesions. The treatment is primarily complete excision of the tumour, followed in some cases by intense chemotherapy. PPB is a strong predictor of the presence of tumours in close relatives. Four patients treated at our institute are discussed along with a review of the literature.

Child, Preschool↗
PubMed2000

Pulmonary sequestration presenting as a prenatally detected suprarenal lesion in a neonate.

An echogenic suprarenal mass was detected antenatally in the fetus by routine ultrasound scan. Resection of the mass after delivery confirmed an extralobar pulmonary sequestration with features of a type II congenital cystic adenomatoid malformation of the lung. The lesion should be considered in all neonates presenting with a suprarenal or upper abdominal mass particularly when the mass has been detected antenatally. Ultrasound-guided needle biopsy if feasible could provide a reasonably confident diagnosis. Congenital anomalies in other organs should be looked for carefully.

Abdominal Neoplasms↗
PubMed2000

Temporary hearing impairment after general anesthesia--a case report.

The incidence of hearing impairment after anesthesia is rare. We report a case who received left total knee and hip replacement and developed severe hearing impairment of the left ear after general anesthesia. Examination of the left ear by an otolaryngologist showed that there was no noticeable abnormality. The hearing acuity recovered gradually and returned to normal 3 days later. The use of nitrous oxide during anesthesia was incriminated as the possible cause.

Anesthesia, General↗
PubMed2000

Chinese attitudes to institutional care of their aged. A study of members from the Chung Wah Association, Western Australia.

OBJECTIVE: To examine Chinese attitudes to institutional care of their aged and to identify the factors that influence these attitudes. METHOD: A cross sectional survey of 815 randomly selected members of the Chung Wah Association, Western Australia was undertaken in 1997 using a mailed self administered questionnaire. The survey instrument was developed through a literature review, interviews and pilot testings and consisted of categorical and noncategorical items. The data were analysed using the SAS (V 6.12) software package. Factor analysis, logistic regression and Chi-square analysis were used on the data. The statistical significance level was set at p < or = 0.05. RESULTS: A total of 431 (53%) completed responses were received. The study showed that 86% of the respondents agreed that the disabled elderly should be institutionalised. Age contributed mainly to the respondents' attitudes to institutionalising the disabled elderly, while the respondents' sex, education, occupation, country of origin and length of residence in Australia did not. Social responsibilities together with the health factors of the elderly had important effects on these attitudes. About 55% of respondents agreed that their Chinese culture influenced their attitude. Only 21% of the respondents agreed that the nondisabled elderly should be institutionalised, 54% disagreed, while 24% remained neutral. Respondents who were likely to institutionalise their disabled elderly were also unlikely to live with their children when they became disabled. A majority of respondents were in favour of government funding of institutions and care givers of the elderly. CONCLUSION: The study provided several important observations and information for health planners and general practitioners to identify the aged at risk of institutionalisation and make arrangements for community support for effected families so that the aged can be encouraged to remain with their families.

Adolescent↗
PubMed2000

Subcutaneous primitive neuroectodermal tumour in the abdominal wall of a child: long-term survival after local excision.

Tumours of the peripheral primitive neuroectodermal tumour/Ewing's sarcoma (PNET/ES) family can rarely occur as primary lesions within the skin and subcutis. We present a case of subcutaneous PNET within the abdominal wall of a 33-month-old child. Histologically it was a small round cell tumour that marked strongly for CD99 and displayed ultrastructual evidence of neural differentiation. The tumour was completely excised, but due to an initial misdiagnosis no adjuvant therapy was given. Despite this, the patient is well without evidence of disease 10 years and 3 months after surgery. A review of similar cases reveals not all patients are as fortunate, suggesting combination therapy, including chemotherapy, is still the best treatment for these tumours, even when small and superficial. Our report therefore highlights the importance of recognising PNET/ES in the skin and subcutis so appropriate therapy can be administered.

12E7 Antigen↗
PubMed1999

Childhood cancer in New Zealand 1990 to 1993.

An epidemiological study of childhood cancer in New Zealand identified 409 children aged 0 to 14 years with malignant neoplasms newly diagnosed between 1990 and 1993 inclusive. The original microscopic material on which the diagnoses were based was reviewed in 398 cases and the neoplasms were allocated into the 12 major groupings and 48 further subcategories of the International Classification of Childhood Cancer (ICCC). The pathology reviewers agreed with group and subcategory classification of the confirmed cancers in all but one case of acute leukemia and three cancers of the central nervous system. Changes were also made in the FAB classification of three cases of acute non-lymphocytic leukemia and in the further subcategorisation of three Hodgkin's lymphomas and ten astrocytomas. The results show a high level of diagnostic accuracy for confirmed childhood neoplasms in that time period. Nine of 15 cases of malignant melanoma notified to the study were not confirmed for various reasons, which included a change in the pathological diagnosis in four cases. Compared with Victoria (Australia), New Zealand has a high incidence rate of lymphomas in boys and an unusual female preponderance of Wilms' tumor cases.

Adolescent↗
PubMed1999

Low dose ketamine and midazolam as supplements for spinal anesthesia.

BACKGROUND: Low dose ketamine and midazolam together were used as supplements during spinal anesthesia to provide analgesia for insertion of spinal needle and intraoperative sedation. METHODS: Two regimens of drug combination (ketamine 0.5 mg/kg and midazolam 0.05 mg/kg in group I, n = 30; ketamine 0.5 mg/kg and midazolam 0.1 mg/kg in group II, n = 30) were administered intravenously before proceeding lumbar puncture. RESULTS: Systolic and diastolic arterial blood pressure, heart rate, and arterial oxygen saturation did not change significantly before and after the administration of drugs. Most patients in both groups showed good analgesic response to the lumbar puncture. The medications induced a brief unconsciousness (4.1 min in group I; 8.5 min in group II). The time from drug administration to recovery of mental orientation was 8.8 min in group I and 15.1 min in group II. The regimens also provided intraoperative sedation. Patients in group II appeared to be more depressed than group I in the first 30 min. None of the patients had significant respiratory disturbance, involuntary movement, or recall to spinal puncture. There were 7 patients in group I and 4 patients in group II who experienced dreaming. CONCLUSIONS: The use of low dose ketamine together with midazolam as supplement for spinal anesthesia is helpful in anesthetic practice.

Adolescent↗
PubMed1997

Juvenile granulosa cell tumor of the testis: report of two cases in newborns.

Two juvenile granulosa cell tumors in the testes of two newborns are described. The lesion, though rare, should be considered whenever a cystic testicular mass is encountered in newborns or young infants. Orchidectomy is the only treatment required because local recurrence or metastases have never been observed. Karyotyping of the patient is essential when the external genitalia are abnormal.

Granulosa Cell Tumor↗
PubMed1997

Utilisation of Australian health care services by ethnic Chinese.

Australia is a multicultural society in which migrants from non-English-speaking backgrounds may be more vulnerable to illness after their new settlement, and language difficulties and cultural differences may affect their use of health services. The present qualitative study used focus group interviews to explore the health services used by Chinese migrants from Hong Kong and China. The general findings included strong preference for Chinese-speaking general practitioners, insufficient interpreter services, low use of preventive services, and lack of knowledge about the existence and role of ethnic health workers. The paper reports specific differences between migrants from China and Hong Kong, and by age group. It discusses reasons for these findings and notes the implications.

Adult↗
PubMed1996

Assessment of invasive growth pattern and lymphocytic infiltration in colorectal cancer.

A total of 122 specimens of colorectal cancer were re-assessed in relation to the reporting of invasive growth pattern (expanding vs. infiltrating) and presence or absence of peritumoral lymphocytic infiltrate as used in the Jass prognostic classification. Jass agreed with 69% of cases reported as infiltrating and 90% of reported as expanding. This parameter was distributed similarly amongst Dukes B and C cases in the original assessment (P = 0.27), whereas in the reviewed data infiltrating cases were more likely to be staged as Dukes C (P = 0.04). Jass agreed with 44% of lymphocyte present and 94% of lymphocyte absent assessments. The original lymphocyte assessments showed no significant differences in distribution between Dukes A and B cases (P = 0.12) or B and C cases (P = 0.75), whereas the reviewed data showed significant differences for A vs. B (P = 0.015) and B vs. C cases (P = 0.0025). Criteria for assessment were circulated to eight observers who revisited 20 of the cases in which there was disagreement. Consensus agreement with Jass was achieved in nine of 10 cases for invasive growth pattern and seven of 10 cases for lymphocyte infiltration (with two being evenly split). Most observers showed at least fair levels of agreement with Jass and some achieved excellent levels of agreement. This study indicates that assessment of criteria used in the Jass prognostic system for colorectal cancer is less than optimal in routine practice, but is improved through the provision of simple guidelines.

Colorectal Neoplasms↗