PubMed Health⌕ Search

Biomedical subjects

K L Chan

Publications and source records attributed to K L Chan.

At least 199 records · Page 11Linked to original sources
PubMed1991

Efficacy of diethylcarbamazine and pirimiphos-methyl residual spraying in controlling brugian filariasis.

A control programme against subperiodic brugian filariasis was implemented in three villages, (Kg. Ampungan, Kg. Sebangkoi and Kg. Sebamban) in Sarawak, Malaysia. In Kampong Ampungan, the mass administration of diethylcarbamazine (DEC-citrate) combined with residual house spraying of pirimiphos-methyl reduced microfilarial rate to 8% of the pre-treatment level and microfilarial density (MfD50) to 44% of the pre-treatment level over a period of four years. In Kampong Sebangkoi and Kampong Sebamban, where only mass DEC therapy was applied, the microfilarial rate and MfD50 declined distinctly in the second blood survey but increased gradually in two subsequent follow-up blood surveys. In Kg, Ampungan, we observed a significant reduction of infective biting rate (88.3%), infection rate (62.5%) and transmission potential (88.1%) of Mansonia bonneae at the fourth spray round. The corresponding reduction rates in Kg. Sebangkoi and Kg. Sebamban were 35.3%, 26.7%, 42.2% and 24%, 30.8% and 15.4% respectively. The biting density of the vector was reduced by 79.8% indoors and 31.8% outdoors at the sprayed village, while only a slight decrease in densities (17.9% indoors and 12.4% outdoors) was observed at the unsprayed village. Bioassay tests revealed that pirimiphos-methyl had a substantial fumigant effect on the vector. The integrated control measure in controlling subperiodic brugian filariasis is discussed.

Adolescent↗
PubMed1990

Anatomic correlations of the long-axis views in biplane transesophageal echocardiography.

The number of views obtainable during transesophageal echocardiography (TE) has been limited by the fixed position of the transducer at the end of the probe. This has confined standard TE studies to short-axis tomography of the heart and aorta. Recently, a biplane TE probe has become available that is capable of both long- and short-axis imaging. This study prospectively assessed the application of the long-axis plane of the biplane probe in providing complementary long-axis views in ambulatory patients. Six standard long-axis views could be obtained and were compared with corresponding anatomic sections to illustrate anatomic relations and facilitate structure identification. The long-axis views provide a better appreciation of the 3-dimensional nature of cardiac anatomy and function, especially in demonstrating the relation of vertically aligned structures.

Adult↗
PubMed1990

Physical examination and echo Doppler study in the assessment of femoral arterial complications following cardiac catheterization.

Femoral arterial complications following cardiac catheterization have been well recognized. The development of an inguinal mass in these patients can represent a simple hematoma, a pseudoaneurysm, or an arteriovenous fistula. The utility of the physical examination in diagnosing these complications was assessed by using the echo Doppler study for comparison. This study shows that any single clinical sign should not be used in isolation, but a constellation of physical findings can suggest the correct diagnosis.

Aged↗
PubMed1990

Oleosin isoforms of high and low molecular weights are present in the oil bodies of diverse seed species.

Oleosins are unique and major proteins localized on the surface of oil bodies in diverse seed species. We purified five different oleosins (maize [Zea mays L.] KD 16 and KD 18, soybean [Glycine max L.] KD 18 and KD 24, and rapeseed [Brassica campestris L.] KD 20), and raised chicken antibodies against them. These antibodies were used to test for immunological cross-reactivity among oleosins from diverse seed species. Within the same seed species, antibodies raised against one oleosin isoform did not cross-react with the other oleosin isoform (i.e. between maize oleosins KD 16 and KD 18, and between soybean oleosins KD 18 and KD 24). However, the respective antibodies were able to recognize oleosins from other seed species. Where interspecies cross-reactivity occurred, the results suggest that there are at least two immunologically distinct isoforms of oleosins present in diverse seed species, one of lower M(r), and another one of higher M(r). This suggestion is also supported by the relative similarities between the amino acid sequence of a small portion of rapeseed oleosin KD 20 and those of maize oleosins KD 16 and KD 18. In maize kernel, there was a tissue-specific differential presentation of the three oleosins, KD 16, KD 18, and KD 19, in the oil-storing scutellum, embryonic axis, and aleurone layer. The phylogenetic relationship between the high and low M(r) isoforms within the same, and among diverse, seed species is discussed.

Journal Article↗
PubMed1990

The effect of Bacillus thuringiensis israelensis [H-14] on emergence of Mansonia mosquitos from natural breeding habitat.

The measurement of the ultimate effects of the microbial insecticides on mosquito density is best obtained by assessment of adult populations. The main aims of this study are: (1) to assess the effect of Bacillus thuringiensis israelensis (Bti) FC Skeetal and Bactimos briquettes on the emergence rate of Mansonia bonneae developed from the introduced first-instar stage larvae and (2) to measure the effect of these two formulations of insecticides on Mansonia adult populations emerging from the natural breeding plots. Bti Skeetal and Bactimos briquettes at the lower applied dosages of 2.3 kg/ha and 1 briquette case/20 m2 respectively achieved 39-40% pupation rates and 31.5-34.2% adult emergence rates. At these low applied dosages, there was little or no direct effect on pupation from the surviving larvae and thereafter on the emergence of adults from the pupae. A two-fold increase in dosage, however, produced a drastic decline in the pupation rate and adult emergence rate. The rates dropped to 6.5% (pupation) and 4.3% (adult emergence) of the total larvae for Bactimos briquettes and to merely 1.5% (pupation) and 1.3% (adult emergence) of the total larvae for Skeetal. In studying the effect of Bti on the field populations of Mansonia mosquitos, two plots each were treated with Bactimos at 1 briquette case/10 m2 and Skeetal at 4.6 kg/ha. A wooden pyramid-shaped screened cage was placed on a cluster of host plants for a period of 2 weeks to trap the emerging adult mosquitoes. There were a total of 24 clusters of host plants in each plot.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Double-blind randomized study of prolonged higher-dose oral amoxycillin in purulent bronchiectasis.

Thirty-eight patients with bronchiectasis and daily expectoration of purulent sputum despite conventional antibiotic courses were randomly allocated to receive a sachet of amoxycillin (3 g) or matched placebo twice daily for 32 weeks in a double-blind study. Nine patients (four amoxycillin, five placebo) were withdrawn from the study treatment; the response of the two patients (both on amoxycillin) withdrawn within the first six weeks was not assessed. The pretreatment characteristics of the two groups were similar. Independent assessment of overall response based on patients' diary cards showed that a higher proportion improved in the amoxycillin group (11 of 17) than in the placebo group (four of 19; p = 0.02). Patients in the amoxycillin group spent significantly less time confined to bed and away from work during treatment. The frequency of exacerbations during the study treatment phase was similar in the two groups but they were less severe than before study treatment in the amoxycillin group. There was a greater reduction in purulent sputum volume between exacerbations during the study treatment in the amoxycillin group to 20 per cent of pretreatment volume than in the placebo group (88 per cent of pretreatment volume, p = 0.008), although the concentrations of Haemophilus spp. in sputum between exacerbations was similar in the two groups. Adverse effects experienced were minor except in one patient (amoxycillin) withdrawn after developing a rash and in six patients (three amoxycillin, three placebo) who had diarrhoea lasting more than one week necessitating withdrawal of two patients (one amoxycillin, one placebo) from study treatment. Sputum and stool cultures collected regularly during the study showed no important changes in the bacterial flora in either group. Prolonged higher-dose antibiotic therapy in these patients with severe purulent bronchiectasis significantly reduced the host (patient) inflammatory response to colonizing microorganisms and reduced morbidity.

Adult↗
PubMed1990

Upper urinary tract tumours in Hong Kong (1972-1987).

A retrospective analysis of all primary upper urinary tract tumours (300) filed in the pathology department of a regional hospital in Hong Kong during 1972-87 showed that renal cell carcinoma (143) was the commonest malignant tumour. Transitional cell carcinoma of the renal pelvis (62) was the next most frequent. Fibromas, which occurred as frequently as angiomyolipomas (28) and outnumbered tumours such as squamous cell carcinoma (13) and nephroblastoma (12), were of little clinical significance since they were invariably incidental findings. Nephrectomies were seldom performed for kidneys involved in secondary malignancies. Rare tumours encountered were adenocarcinoma of the renal pelvis, leiomyosarcoma, malignant fibrous histiocytoma, adenoma, oncocytoma, mesoblastic nephroma and multilocular cystic nephroma. Angiomyolipomas were responsible for most cases of surgical emergency.

Adolescent↗
PubMed1988

Thrombin enhances opsonized zymosan-induced chemiluminescence of neutrophils.

We examined the effects of alpha-thrombin (the native enzyme) on neutrophil activation as assessed by the measurement of chemiluminescence. alpha-Thrombin in physiological concentrations (10(-9)-10(-8)M) did not induce neutrophil chemiluminescence. However, when neutrophils were coincubated with opsonized zymosan and alpha-thrombin, the chemiluminescence response to opsonized zymosan was enhanced in a concentration-dependent manner. The neutrophil chemiluminescence responses to opsonized zymosan and to opsonized zymosan plus alpha-thrombin were dependent on the generation of oxygen-derived free radicals since the chemiluminescence was inhibited by superoxide dismutase. The results indicate that thrombin per se does not induce neutrophil chemiluminescence. However, thrombin enhances the chemiluminescence response to opsonized zymosan suggesting an interaction between thrombin and complement receptors in inducing neutrophil activation. The chemiluminescence response to thrombin and opsonized zymosan is the result of oxygen-derived free radicals.

Animals↗
PubMed1988

Multilocular cyst of the kidney.

Four examples of multilocular cyst of the kidney occurring in adult Chinese women are reported. This uncommon lesion has distinctive sonographic and clinicopathological features. The aetiology and pathogenesis are unknown. The differential diagnosis, pre-operative evaluation, and treatment are discussed.

Adult↗
PubMed1988

Doppler demonstration of the mechanism of mitral regurgitation mimicking aortic stenosis.

Seven patients with prolapsed posterior mitral leaflet were identified in whom the clinical findings were suggestive of aortic stenosis. In each instance, the murmur was best appreciated at the parasternal area. The murmur radiated to the carotids in two patients. Spatial mapping with pulsed-wave Doppler as well as continuous-wave Doppler examination demonstrated the presence of mitral regurgitation and also that the regurgitant stream was directed to the anterior left atrial wall near the base of the aorta.

Adult↗