Biomedical subjects

Y L Chan

Publications and source records attributed to Y L Chan.

At least 91 records · Page 5Linked to original sources

PubMed1998

Operating in turbulent times: how Ontario's hospitals are meeting the current funding crisis.

With the escalation of the cost of providing health care in Ontario, politicians have begun to attempt to stay the increase by curtailing hospital funding. This article reports on an interview survey of 15 randomly chosen Ontario hospitals that are attempting to cope in the current funding cutbacks. Overall, we found our sample hospitals to be an innovative group on the whole, which were willing to try out new ideas and adapt to the changing environment while protecting quality of patient care.

Cost Control↗

PubMed1998

Comparison of local infiltration of tenoxicam and intravenous tenoxicam for postoperative analgesia in herniorrhaphy.

BACKGROUND: The major complaint of herniorrhaphy is postoperative pain which occurs during the first 24 h after operation. Tenoxicam has a long half-life of 60-80 h. Local infiltration of the drug concentrates the pain control effects in the local area. The local infiltration dose can be smaller than the recommended systemic dose needfully to reach the target area to be effective. Therefore we studied the effect of preoperative local infiltration of tenoxicam on postoperative pain. METHODS: Sixty patients, belonging to ASA classes I and II, undergoing unilateral herniorrhaphy, were randomly assigned to 4 groups. General anesthesia was induced with thiamylal 5 mg/kg, fentanyl 2 micrograms/kg, and atracurium 5 mg/kg. Group 1 (G1) patients were preoperatively injected with 10 mg of tenoxicam in 10 ml normal saline or distilled water, in the operative area. Group 2 (G2) and Group 3 (G3) patients were preoperatively given intravenous tenoxicam, 20 mg and 10 mg, respectively. Group 4 (G4) patients were not given preoperative local infiltration or intravenous tenoxicam to serve as control group. The pain score was assessed at 2 h, 9 h, 24 h postoperatively in all groups. We recorded the total amount of acetaminophen used and the form of administration of the analgesic drug. All patients received general anesthesia in uniform technique. RESULTS: Pain score and amount of analgesic drug required in G1 (local infiltration group) patients were significantly decreased compared with the other groups. The postoperative pain score of Visual Analog Scale (VAS) and analgesic requirement in the four groups were ranked as follows: G1 < G2 < G3 < G4. No significant difference was observed between G2, G3 and G4. Only the pain score in G2 patients significantly decreased (p < 0.05) during the late postoperative period (24 h) when compared with G4 patients. CONCLUSIONS: Preoperative local infiltration of tenoxicam can decrease postoperative pain score significantly during the most painful period (24 h) in herniorrhaphy.

Adult↗

PubMed1998

Views of obstetric patients who refuse regional anesthesia in cesarean section.

BACKGROUND: Regional anesthesia for cesarean section has gained widespread popularity. However, there are still a good few of obstetric patients who refuse it. This study was to investigate the reasons for refusing regional anesthesia in order to gain some insights into the attitudes and concerns of patients. METHODS: Three hundred and twenty-four obstetric patients scheduled for Cesarean section were interviewed just before entering the operating room. They were asked to give one or two reasons for refusing regional anesthesia. RESULTS: Two hundreds of them refused regional anesthesia. The most frequent reasons were apprehension of witnessing the operation (auditory or visional) (45.42%) and fear of backache following regional anesthesia (14.58%). CONCLUSIONS: Anesthesiologists should be aware of patients' feeling or concern and could be capable and willing to discuss with them the relevant problems.

Adolescent↗

PubMed1998

Cranial actinomycosis.

A 67-year-old man presented with actinomycotic osteomyelitis of the skull and underlying central nervous system (CNS) involvement. The computed tomography (CT) and magnetic resonance imaging (MRI) findings are discussed and the radiological literature is reviewed.

Actinomycosis↗

PubMed1997

Retropharyngeal lymphadenopathy in nasopharyngeal carcinoma.

BACKGROUND: This study was done to investigate the size of normal retropharyngeal lymph nodes (RLN) and the incidence of retropharyngeal lymph node involvement in patients with nasopharyngeal carcinoma (NPC). METHODS: Forty-four NPC patients who had not yet received treatment and 20 control subjects underwent MRI scanning. The number and the maximum diameter of the short axis of the cervical lymph nodes were measured. The number of nasopharyngeal walls involved and the maximum diameter of the tumor were recorded. RESULTS: In 5 of 20 control subjects lateral RLN were identified; none of these nodes was greater than 2.5 mm. In the NPC patients, taking 4 mm as the upper limit of normal RLN, 89% of the patients had enlarged RLN. The number of nasopharyngeal walls involved and the maximum diameter of the primary tumor showed no statistical relationship with the involvement of RLN. There was a statistical association between RLN and level II node involvement, but not with other groups of neck nodes. CONCLUSION: Of all patients with NPC, 89% showed enlarged RLN. Its involvement was related to level II nodes but not to the number of nasopharyngeal sites involved nor with the maximum diameter of the tumor.

Adult↗

PubMed1997

Detectability and appearance of bile duct calculus on MR imaging of the abdomen using axial T1- and T2-weighted sequences.

This is a retrospective study with the objective of assessing the appearance and detectability of bile duct calculi on axial abdominal magnetic resonance imaging (MRI). Axial spin-echo (SE) T1-weighted and Turbo-spin-echo (TSE) T2-weighted images of the upper abdomen of 23 patients suffering from acute cholangitis with known bile duct calculi were retrospectively analysed. Bile duct calculi could be visualized on a T1-weighted SE sequence in 10 (47%) patients. T2-weighted TSE images identified bile duct calculi in 20 (87%) patients. On the T1-weighted sequence, eight out of 10 (80%) visualized common duct stones were slightly hyperintense compared to bile. On T2-weighted sequence, 27 out of 34 (79%) detectable common duct stones were uniformly hypointense compared to bile, but seven stones (21%) had mixed signal intensity.

Adolescent↗

PubMed1997

MRI and CT of metastatic hepatocellular carcinoma causing spinal cord compression.

We report the imaging features in five patients with metastatic hepatocellular carcinoma causing spinal cord compression, three of which were biopsy proven and two were in patients with known diagnosis of hepatocellular carcinoma. The radiographic, magnetic resonance imaging (MRI) and computed tomography (CT) features are highlighted. Although the occurrence of metastatic disease in hepatocellular carcinoma is exceedingly rare, it may be increasingly encountered as survival of patients is improved with advancing methods of therapy, both surgical and palliative. It often accompanies local recurrence, and invariably signals a grave prognosis with extremely short life expectancy. Unusually, two of the five patients in this series presented initially with skeletal metastases which led to the diagnosis of hepatocellular carcinoma.

Adult↗

PubMed1997

Sonographic appearance of hepatic Langerhans cell histiocytosis.

Periportal lesions were detected on ultrasound in two cases of Langerhans cell histiocytosis with liver involvement. Hypoechoic or hyperechoic lesions were detected in different stages of evolution. Hyperechoic lesions probably corresponded to periportal inflammation whilst hyperechogenicity suggested xanthomatous change.

Disease Progression↗

PubMed1997

Sonographic evaluation of hip effusion in children. Improved visualization with the hip in extension and abduction.

PURPOSE: To assess the difference in the sonographic appearance of hip effusions when the hip was placed in the extended and abducted position as compared to a neutral position. MATERIAL AND METHODS: Twenty-one consecutive children (aged 2-14 years) with hip pain or limping were examined for hip effusions by means of ultrasound. The capsule-femoral-neck distance, the presence of joint fluid, and the shape of the anterior capsule were compared in hips in slight extension and abduction with those in hips in a neutral position. RESULTS: Of the 11 positive hip effusions, the maximal distance between the capsule and femoral neck was significantly larger (p < 0.005) in the extended and abducted hip position than in the neutral hip position, with a mean difference of 1.6 mm. Convex bulging of the anterior capsule was more confidently diagnosed in 3 hip effusions in the extended and abducted hip, and better visualization of fluid between the capsule and femoral neck was achieved in 4 joint in this posture. CONCLUSION: The study demonstrated an improvement in the sonographic detection of hip effusion in the extended and abducted position compared to the neutral position.

Adolescent↗

PubMed1997

Central diabetes insipidus in a newborn with deletion of chromosome 7q.

We report an infant with midline craniofacial defects and holoprosencephaly due to chromosome 46, XY, del (7) (pter-->q34) who presented at 1 week of age with central diabetes insipidus. The importance of hypothalamic-pituitary endocrine investigation in patients with this syndrome, and more generally, in patients with midline craniofacial malformation or holoprosencephaly is emphasized. As infants with chromosome 7q deletion bear close phenotypic resemblance to infants of Trisomy 13, chromosomal confirmation and karyotype banding is mandatory to establish an accurate diagnosis and for genetic counselling of their parents.

Abnormalities, Multiple↗

PubMed1997

Comparison of T2 weighted fat suppressed turbo spin echo and contrast enhanced T1 weighted spin echo MRI in nasopharyngeal carcinoma.

Fat suppressed T2 weighted fast imaging sequences have recently been favoured in MRI of head and neck tumours. The purpose of this study was to evaluate the use of T2 weighted fat suppressed turbo spin echo (T2W SPIR) and compare it with our standard technique, the gadolinium-enhanced T1 weighted spin echo (Gd-T1W SE). The MR images of 36 patients with nasopharyngeal carcinoma were analysed for local tumour extent. T2W SPIR was better in evaluating tumour extension into the clivus and fascia. In all other regions Gd-T1W SE was either better (nasopharyngeal walls, small parapharyngeal muscles, parapharyngeal fat space, paranasal sinuses, pterygomaxillary fissure and pterygoid process) or equal (nasal cavity, oropharynx, cranial fossa and cavernous sinus) to T2W SPIR. T2W SPIR was unable to replace Gd-T1W SE in evaluation of tumour extent because of loss of signal from magnetic susceptibility artefact, poor delineation of anatomical detail and reduced tumour conspicuity. The use of T2W SPIR as an additional sequence may be warranted in selected cases but cannot replace Gd-T1W SE.

Adult↗

PubMed1997

Visceral fat and cardiovascular risk factors in Chinese NIDDM patients.

OBJECTIVE: The interrelations between obesity, glucose intolerance, hypertension, dyslipidemia, and insulin resistance are well recognized. These relationships are of particular interest in Hong Kong's Chinese population, in whom increasing affluence has coincided with a marked increase in the prevalence of NIDDM. We designed a pilot study to examine the relationships between visceral fat and cardiovascular risk factors in Chinese NIDDM patients. RESEARCH DESIGN AND METHODS: We studied 21 Chinese NIDDM patients whose visceral fat was quantified by magnetic resonance imaging. Cardiovascular risk factors including plasma lipids and 24-h ambulatory blood pressure (BP) were measured. In addition, insulin resistance was determined by a short insulin tolerance test (SITT). RESULTS: Increased visceral adiposity was significantly correlated with plasma triglycerides (r = 0.63, P = 0.004), the total cholesterol/HDL cholesterol ratio (r = 0.61, P = 0.008), the urinary albumin/creatinine ratio (r = 0.49, P = 0.04), and decreased insulin sensitivity as measured by the SITT (r = 0.47, P = 0.03). When the data were analyzed by tertiles, increasing visceral fat area was associated with higher plasma triglycerides, lower HDL cholesterol, and a smaller plasma glucose decrement during the SITT. In addition, the diurnal rhythm in BP and heart rate tended to be best preserved in those with the least visceral obesity. CONCLUSIONS: This pilot study demonstrates that visceral fat accumulation is associated with dyslipidemia, hypertension, insulin resistance, and albuminuria in Chinese patients with NIDDM.

Adipose Tissue↗

PubMed1997

Dyspnea resulting from phrenic nerve paralysis after interscalene brachial plexus block in an obese male--a case report.

Phrenic nerve paralysis is a common complication in interscalene brachial plexus block. This complication is often ignored by most anesthesiologists because no clinical symptoms occur in patients who have no underlying lung disease. We present a case of an obese male suffering from dyspnea due to phrenic nerve block after interscalene brachial plexus block. The decreased respiratory reserve and direct compressing effect of the abdominal organs on the diaphragm in the supine position are thought to be the risk factors in this obese patient. Also discussed are the incidence, diagnostic methods, clinical presentation and treatments of phrenic nerve paralysis during interscalene brachial plexus block.

Adult↗

PubMed1997

Clinics in diagnostic imaging (29). Thalassaemia major with iron overload.

A 5-year-old girl presented with lethargy, anaemia and facial distortion. Both parents had beta-thalassaemia minor. Radiographs confirmed the characteristic features of thalassaemia major. A treatment regime comprising regular blood transfusions was commenced. The basis of the radiographic changes and the current role of magnetic resonance imaging, particularly with respect to assessing iron overload, are emphasized.

Blood Transfusion↗

PubMed1996

The primary structures of rat ribosomal proteins S3a (the V-Fos transformation effector) and of S3b.

The amino acid sequence of the rat 40S ribosomal subunit protein S3a was deduced from the sequence of nucleotides in two recombinant cDNAs and confirmed by the determination of the NH2-terminal sequence by Edman degradation. Ribosomal protein S3a has 263 amino acids (the NH2-terminal methionine is removed after translation of the mRNA) and the molecular weight is 29,794. The protein designated S3b has the same amino acid sequence as S3a except that it lacks the carboxyl-terminal 12 residues. We are unable to determine whether there are separate genes for S3a and S3b, or whether there is a single gene and alternate splicing of the precursor to yield separate mRNAs for S3a and S3b, or whether there is a single gene and a single mRNA whose translation yields S3a which is converted by proteolysis, either physiological or fortuitous, to S3b. The mRNA for S3a is about 1000 nucleotides in length. Hybridization of cDNA to digests of nuclear DNA suggests that there are 8-13 copies of the S3a gene. Rat ribosomal protein S3a is identical to the product of the rat Fte-1 gene which encodes the V-Fos transformation effector; S3a is also related to the plant protein cyc07, which is encoded by a cell cycle S-phase specific gene.

Alternative Splicing↗

PubMed1996

The primary structure of rat ribosomal protein L10: relationship to a Jun-binding protein and to a putative Wilms' tumor suppressor.

The amino acid sequence of the rat 60S ribosomal subunit protein L10 was deduced from the sequence of nucleotides in two recombinant cDNAs and confirmed by determination of the NH2-terminal amino acid sequence in the protein. Ribosomal protein L10 has 213 amino acids (the NH2-terminal methionine is removed after translation of the mRNA); the molecular weight is 24,456. Hybridization of the cDNA to digests of nuclear DNA suggests that there are 8 to 10 copies of the L10 gene. The mRNA for the protein is about 900 nucleotides in length. Rat L10 is related to ribosomal proteins from other eukaryotes. Ribosomal protein L10 is, in addition, the mammalian homolog of the chicken Jun-binding protein and is nearly identical to a putative Wilms' tumor suppressor. This is a presumptive example, of which there are many others, of an extraribosomal function of a ribosomal protein.

Amino Acid Sequence↗

PubMed1996

The primary structure of rat ribosomal protein L14.

The amino acid sequence of the rat 60S ribosomal subunit protein L14 was deduced from the sequence of nucleotides in two recombinant cDNAs. Ribosomal protein L14 has 213 amino acids (the NH2-terminal methionine is removed after translation of the mRNA); the molecular weight is 23,193. Hybridization of the cDNA to digests of nuclear DNA suggests that there are 6 to 8 copies of the L14 gene. The mRNA for the protein is about 800 nucleotides in length. Rat L14 is related to a number of previously unidentified ribosomal proteins from other eukaryotes but not to any from archaebacteria or eubacteria. The carboxyl-terminal amino acid sequences of rat L14 and of chicken histone H1 are related. Mutation of the Drosophila melanogaster homolog of rat L14 causes a severe Minute phenotype.

Amino Acid Sequence↗

PubMed1996

Detection of axillary lymph node metastases in breast carcinoma by technetium-99m sestamibi breast scintigraphy, ultrasound and conventional mammography.

Axillary lymph node status is important in the staging of breast carcinoma. To evaluate the accuracy of technetium-99m sestamibi breast scintigraphy in detecting metastatic axillary lymph nodes as compared with other accepted imaging modalities, we performed 99mTc-sestamibi breast scintigraphy, conventional mammography and ultrasound in 36 patients with primary untreated breast carcinoma. With histopathology as the gold standard, 99mTc-sestamibi breast scintigraphy was found to yield true-positive results in 7 of 11 cases (64%) of axillary lymph node metastases and true-negative results in 18 of 20 cases (90%); it has an accuracy of 81%, a positive predictive value of 77.8% and a negative predictive value of 81.8%.

Axilla↗