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Biomedical subjects

K L Chan

Publications and source records attributed to K L Chan.

At least 163 records · Page 9Linked to original sources
PubMed1995

A study of post-stroke depression in a rehabilitative center.

This was a prospective study of 52 stroke patients. The incidence of post-stroke depression was 55%. A past history of depression was significantly associated with the clinical assessment of depression. There was no association between the clinical assessment of depression and type and site of lesion and intellectual impairment. The clinical assessment of depression was significantly associated with the degree of functional impairment. The clinical assessment of depression also correlated well with Hamilton Depression Rating Scale score. We conclude that post-stroke depression is unlikely to be caused by neuronal injury due to the cerebrovascular accident. There is also a significant reactive component to it. The Hamilton Depression Rating Scale is suitable for assessing the severity of depression in stroke patients.

Activities of Daily Living↗
PubMed1995

Reduced in-hospital mortality from acute myocardial infarction with general adoption of thrombolytic treatment in the North West Thames health region 1979-1991.

OBJECTIVE: To determine the impact of studies of thrombolytic treatment in acute myocardial infarction on inhospital mortality. DESIGN: Retrospective study. SETTING: All 21 major hospitals in the North West Thames health region. PATIENTS: 63,903 patients with acute myocardial infarction. STUDY PERIOD: 1979-1991. MAIN OUTCOME MEASURES: in-hospital mortality. RESULTS: Overall mortality decreased by 5.2% from 25.4% to 20.2% (P < 0.0001) (95% confidence interval (CI) 3.4 to 6.6). Male mortality decreased by 6.5% from 22.3% to 15.8% (P < 0.0001) (95% CI 4.8 to 8.4); female mortality decreased by 4.3% from 32.6% to 28.3% (P < 0.01) (95% CI 1.3 to 7.4). Reductions in mortality occurred in all age and sex groups but were greater in younger patients. Logistic regression analysis of death rates showed that the odds ratio of death in 1991 compared with that in 1979 was 0.75 (95% CI 0.69 to 0.82). After allowing for the effects of age and sex, this odds ratio became 0.54 (95% CI 0.49 to 0.59), as more elderly patients were treated in 1991. Purchase of streptokinase increased 31-fold from 116 doses in 1983 to 3554 doses in 1991. There was a pronounced negative association between annual purchases of streptokinase and mortality (Kendall's rank correlation = -0.86, P = 0.003). Changes in clinical practice resulted in the saving of the lives of an estimated 600 patients with acute myocardial infarction in 1991. This extrapolates to an annual saving of 10,500 lives in the United Kingdom. CONCLUSIONS: In the past few years thrombolytic treatment has been widely adopted for the management of acute myocardial infarction. This has been paralleled by a substantial reduction in in-hospital mortality.

Adult↗
PubMed1995

The association of the amoebic colitis and chronic ulcerative colitis.

Three patients with idiopathic ulcerative colitis and infection of Entamoeba histolytica were reviewed. They represented three different relationships between the two conditions, vis asymptomatic carrier, coexisting infection and superinfection causing exacerbation of colitis. A two-way relationship between amoebic colitis and ulcerative colitis has been discussed and the possible mechanisms in the literature have been reviewed. In patients with a short history of diarrhoea and in tropical countries where amoebic infection is endemic, it is important to role out amoebic colitis before commencing steroid therapy for inflammatory disease.

Adrenal Cortex Hormones↗
PubMed1995

Clinics in diagnostic imaging (6).

A nine-month-old Chinese girl presented with a large buttock mass. Serum alpha-fetoprotein level was elevated. Plain radiographs, computerised tomography and magnetic resonance imaging demonstrated a solid heterogeneous presacral mass. A sacrococcygeal teratoma was excised using the abdominoperineal approach. The patient responded well to multiagent chemotherapy. The features of this tumour are discussed, with emphasis on the role of imaging.

Antineoplastic Agents↗
PubMed1994

Measurement of left ventricular ejection fraction by acoustic quantification and comparison with radionuclide angiography.

Left ventricular (LV) ejection fraction (EF) is an important measure of systolic function, with radionuclide angiography being the accepted standard for its determination. Echocardiography is ideal for repeated measurements of EF, but most methods are either subject to error in the presence of regional wall abnormalities or require cumbersome off-line analysis. Acoustic quantification is a recently introduced method that allows for the continuous on-line display of LV cavity dimensions, but the on-line algorithm for the measurement of EF has not been validated against an independent standard in the clinical setting. This study attempted to validate acoustic quantification in the determination of EF by comparison with off-line echocardiographic analysis and radionuclide angiography in 54 patients referred for this latter procedure. Acoustic quantification correlated well with off-line analysis in both the apical 4-chamber (r = 0.89, n = 43) and 2-chamber (r = 0.86, n = 26) views. Similarly, it also correlated well with radionuclide angiography in the 4-chamber (r = 0.81, n = 44) and 2-chamber (r = 0.83, n = 26) views. The correlation between the 2 methods was further improved when only the last 30 patients were assessed (r = 0.91, n = 25 for 4-chamber views; r = 0.86, n = 16 for 2-chamber views). The correlation was worse in patients with regional asynergy (r = 0.69, n = 17 for 4-chamber views; r = 0.76, n = 10 for 2-chamber views). Moreover, acoustic quantification tended to underestimate EF when compared with radionuclide angiography.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Somatostatin therapy in L-asparaginase-induced pancreatitis.

L-Asparaginase-induced pancreatitis is an uncommon but potentially lethal complication. An 8-year-old girl with acute lymphoblastic leukaemia developed acute pancreatitis following treatment with asparaginase. Clinical and laboratory improvements were evident after treatment with somatostatin, with no complications of pancreatitis. Induction therapy for the leukaemia was able to be continued and complete remission was documented during the course of pancreatitis and somatostatin treatment, suggesting a beneficial role of somatostatin in the management of asparaginase-induced pancreatitis.

Acute Disease↗
PubMed1994

Pancreatic pleural effusion: an indication for emergency distal pancreatectomy and Roux-en-Y pancreatico-jejunostomy.

A previously healthy 2-year-old boy was admitted because of shortness of breath, cough, and fever; there was minimal abdominal pain. He had recurrent right, followed by left pleural effusions, which contained markedly elevated amylase levels and high protein content. The pleural fluid amylase levels were disproportionately higher than the serum amylase levels. His abdominal signs were minimal. Surgical exploration showed a disruption of the proximal pancreatic duct. Distal pancreatectomy and Roux-en-Y pancreatico-jejunostomy were performed. After a complicated postoperative course he was discharged well and has remained so for more than 2 years.

Anastomosis, Roux-en-Y↗
PubMed1994

Recurrent acute pancreatitis induced by isoniazid.

A 31-year-old man on haemodialysis who developed recurrent attacks of acute pancreatitis during the treatment of pulmonary tuberculosis is presented. The pancreatitis rapidly subsided once isoniazid was withdrawn, but the problem recurred again upon reintroduction of the drug. There was no further recurrence during successful treatment with full doses of rifampicin and pyrazinamide for 1 year.

Acute Disease↗
PubMed1994

Histopathological and adhesion formation after incision using ultrasonic vibrating scalpel and regular scalpel in the rat.

OBJECTIVE: To evaluate and to compare changes that occur in the uterine tissue of the rat after a standard incision with an ultrasonic vibrating scalpel and with a regular scalpel. SETTING: Sprague-Dawley white rats (Charles River Canada Inc., St. Constant, Quebec, Canada) in a conventional laboratory setting. INTERVENTIONS: A standardized incision was performed on the uterine horn with a regular scalpel on one uterine horn and with an ultrasonic scalpel on the opposite horn. MAIN OUTCOME MEASURES: Degree of adhesions and histopathological changes of the uterine horns. RESULTS: The degree of adhesion formation was similar, but the uterine horn distal to the incision was dilated in most uterine horns that were incised with ultrasonic scalpel. The degree of coagulation necrosis was significantly higher 7 and 14 days after incision with an ultrasound scalpel than after incision with a regular scalpel. CONCLUSION: The use of an ultrasonic vibrating scalpel is associated with more tissue injury than that of a regular scalpel, but it does not produce more adhesion formation.

Animals↗
PubMed1994

Balloon catheter dilatation of peptic pyloric stenosis in children.

In the past 3 years, three children (ages 2, 4, and 8 years) suffering from peptic pyloric stenosis and repeated vomiting were treated in our department with balloon dilatation followed by H2-receptor antagonist therapy. After the dilatation, all three patients could take solid food without vomiting. There were no complications as a result of the procedures. During a mean follow-up of 17 months (range, 5-30) there was no recurrence of symptoms. The method of dilatation is described, and we recommend it as an option for the initial nonoperative treatment of pediatric peptic pyloric stenosis. The long-term results of balloon dilatation of peptic pyloric stenosis will, however, require further evaluation.

Barium↗
PubMed1994

A study of pre-antibiotic bacteriology in 125 patients with necrotizing enterocolitis.

Over a five-year period, 125 newborns with necrotizing enterocolitis (NEC) were managed by us. Their mean birthweight was 1700 g and mean maturity was 32 weeks. Before commencement of antibiotics, routine septic work-up was done in order to define the bacterial spectrum and antibiotic sensitivity. The study includes aerobic and anaerobic cultures of gastric and pharyngeal aspirates, blood cultures, umbilical swabs and culture of umbilical catheter tips in relevant cases. Peritoneal swab results were also analyzed if laparatomy was performed. Positive cultures were present in 45 patients (36%) with 55 positive specimens. Fifteen types of organism were isolated: the commonest was Enterobacter (29%), followed by E. coli (14.5%) and Klebsiella (13%). They were resistant to ampicillin and first-generation cephalosporin. These organisms were usually opportunistic pathogens. Overgrowth of them may be the cause of NEC. Regular review of the antibiotic sensitivity of these organisms allows prompt and appropriate choice of antibiotics. At the same time, antibiotic sensitivity for these organisms was analyzed to guide us in the choice of antibiotic therapy.

Ampicillin Resistance↗
PubMed1994

Congenitally bicuspid aortic valves: study of a variant with fenestrated raphe.

OBJECTIVE: To illustrate and describe a variant of the congenitally bicuspid aortic valve (BAV) in the context of previous reports of the morphology of BAVs. SETTING: Retrospective review of surgically excised aortic valves at The University of Ottawa Heart Institute in Ottawa, Ontario. DESIGN AND PATIENTS: The clinical, echocardiographic and pathological features of 17 cases with a variant of BAV were examined from patients who had valve replacements performed in the period from January 1, 1986 to December 31, 1992. MAIN RESULTS: A total of 865 patients had native aortic valve replacements during the study period and 291 patients had BAVs. One hundred and eighty-one patients were male (62%) (mean age 60 years) and 110 were female (38%) (mean age 64 years). There were 17 BAVs (6%) where either: the raphe was fenestrated so that only a thin fibrous band (or bands) joined the valve cusp to aortic wall-type A valves (seven cases); or a similar fibrous band (or bands) was seen, but was associated with other usual appearing raphal tissue--type B valves (10 cases). These patients included 15 males (mean age 63 years) and two females (mean age 63 years); they presented with dyspnea and/or angina. Distinction of the number of cusps with this variant was incorrect in six of nine transthoracic echocardiograms, and three of four transesophageal echocardiograms. CONCLUSION: This variant of BAV, with fenestrated raphe, is not well described in the literature, is difficult to diagnose clinically and may present in unusual ways.

Aged↗
PubMed1993

Two approaches to motion analysis of the ultrasound image sequence of carotid atheromatous plaque.

It has been observed, with a sequence of ultrasonic images, that a significant number of carotid atheromatous plaques moved under the influence of cardiovascular forces. The aim of this project was to analyse the movement of the heterogeneous and homogeneous plaques using both the discrete approach and the continuous approach. In order to verify that the movement of plaque is not due to the movement of the transducer or the respiration of the patient, global movement estimation was also carried out. Experimentation on an artificial image sequence showed that both approaches can track the target accurately. These approaches were then applied on clinical image sequences and the results showed that carotid plaque was locally moved as a result of the momentum transfer rather than the global movement of the surrounding normal tissue.

Arteriosclerosis↗
PubMed1993

Implication of negative results on a monoplane transesophageal echocardiographic study in patients with suspected infective endocarditis.

OBJECTIVES: This study was conducted to determine the implications of negative findings on a transesophageal echocardiographic study in which neither a vegetation nor an abscess is identified in patients with clinically suspected infective endocarditis. BACKGROUND: Echocardiography is the procedure of choice for evaluating suspected infective endocarditis in patients. Transesophageal echocardiography has been shown to be superior to transthoracic imaging. Although the importance of positive results or a diagnostic study is known, the significance of negative findings on a transesophageal study is not clear. METHODS: All transesophageal echocardiographic studies performed over a 2-year period for suspected infective endocarditis were reviewed and the clinical course of patients with an initially negative study result was assessed to determine their final diagnosis. RESULTS: Of the 105 patients identified, 65 had a negative transesophageal study result. In the majority of this group (56 of 65), an alternate diagnosis was made or there was no infective endocarditis on follow-up examination, or both. Of the remaining nine patients, four were treated for endocarditis without a definite diagnosis and five had infective endocarditis proved by either repeat transesophageal study (n = 3), pathologic findings (n = 1) or a diagnostic clinical course (n = 1). Gram-positive bacteremia and the presence of a prosthetic valve in the aortic position tended to be more common in the latter group. CONCLUSIONS: A negative transesophageal study result reduces the likelihood that endocarditis is present. Repeat examination, however, should be considered in high risk patients, such as those with prosthetic valves or unexplained bacteremia, to avoid a missed diagnosis.

Adult↗
PubMed1993

Extra-articular manifestations are uncommon in southern Chinese with rheumatoid arthritis.

Rheumatoid arthritis is characterized by both articular and extra-articular manifestations. Few studies have addressed the prevalence of extra-articular manifestations in non-Caucasoid races. We have studied 153 Southern Chinese patients with RA and found that such features are uncommon when compared with previous reports in Caucasoids. The only extra-articular manifestations were rheumatoid nodules which were present in 4.6%, and episcleritis and cutaneous vasculitis in 0.7% each. A further 12.4% had mild sicca symptoms. These findings were in direct contrast with the severity of articular disease as 73% of patients had erosive disease which was graded as severe in 37%. The reason for the low prevalence of extra-articular manifestations is not known but may be due, in part, to the rarity of the HLA-DR4 subtype, HLA-Dw4 in the Southern Chinese population.

Adult↗
PubMed1993

Evidence for a single gene effect causing polycystic ovaries and male pattern baldness.

OBJECTIVE: Polycystic ovary syndrome is one of the most common endocrine disorders but its aetiology remains unknown. It is highly prevalent within families, suggesting a genetic basic for the syndrome, but the mode of inheritance is unclear. The purpose of this study was to determine the mode of inheritance of polycystic ovary syndrome, within the families of affected individuals, by classic segregation analysis. DESIGN: All first degree relatives of affected individuals were screened for the presence or absence of polycystic ovaries in post-menarchal-premenopausal women and early onset male pattern baldness (MPB) in the males. In extended pedigrees, assignment of affected status in post-menopausal women was made by consideration of the clinical history alone. PATIENTS: Fourteen women (probands), presenting with a variety of clinical symptoms, were identified sequentially as having polycystic ovaries (PCO) by ultrasound scan. They were examined in detail to determine their family structure, clinical and endocrine status. Ten families were found to have sufficient members for further study. MEASUREMENTS: All family members had their body mass index calculated, their degree of hirsutism assessed using the Ferriman and Gallwey score and serum levels of gonadotrophins (FSH and LH), testosterone, prolactin and 17 alpha-hydroxyprogesterone measured by radioimmunoassay. A careful reproductive history was taken for each woman and any menstrual disturbance was noted. Obese probands had their glucose and insulin response to a standard 75-g oral glucose tolerance test determined. Each male family member was also assessed for the degree and time of onset of balding. RESULTS: First degree female relatives of affected individuals had a 51% chance of being affected. Early onset male pattern baldness (MPB) was found to be an accurate phenotype for obligate male carriers. Each family showed autosomal dominant inheritance for PCO with greater than 90% penetrance. CONCLUSIONS: We postulate that PCO and male pattern baldness are caused by alleles of the same gene which affect androgen production or action. The different frequencies of PCO and male pattern baldness arise from differing thresholds for phenotypic expression in females and males respectively. The modifying effects of other genes is the most likely explanation of the somewhat variable phenotype.

Adult↗