Search PubMed⌕ Search

Biomedical subjects

M S Chan

Publications and source records attributed to M S Chan.

At least 55 records · Page 3Linked to original sources
PubMed1994

The evaluation of potential global morbidity attributable to intestinal nematode infections.

This paper presents a method of estimating the potential global morbidity due to human intestinal nematode infections (Ascaris lumbricoides, Trichuris trichiura and hookworms), based on the observed prevalence of infection. The method relies on the observed relationships between prevalence and intensity of infection, and between worm burden and potential morbidity. This approach is shown to be sensitive to the precision of the original prevalence estimates and, in particular, to the degree of spatial heterogeneity in levels of infection. The estimates presented here indicate that several tens of millions of children are likely to suffer developmental consequences from infection, and suggest that the global disease burden of geohelminthiasis may be significantly greater than was supposed.

Adolescent↗
PubMed1994

The development and validation of an age-structured model for the evaluation of disease control strategies for intestinal helminths.

Epidemiological modelling can be a useful tool for the evaluation of parasite control strategies. An age-structured epidemiological model of intestinal helminth dynamics is developed. This model includes the explicit representation of changing worm distributions between hosts as a result of treatment, and estimates the morbidity due to heavy infections. The model is used to evaluate the effectiveness of different programmes of age-targeted community chemotherapy in reducing the amount of morbidity due to helminth infection. The magnitude of age-related heterogeneities is found to be very important in determining the results of age-targeted treatment programmes. The model was verified using field data from control programmes for Ascaris lumbricoides and Trichuris trichiura, and was found to provide accurate predictions of prevalence and mean intensities of infection during and following different control regimes.

Adult↗
PubMed1991

A radiological-pathological correlation of hepatocellular carcinoma (HCC).

The histological distribution of lipiodol within hepatocellular carcinoma (HCC) was correlated with that seen on computed tomography (CT), arteriography and high resolution plain films of 15 resected specimens. By means of special stains, the arterially administered lipiodol was shown to be maximally distributed at the periphery of large tumours and nodules. The centre of large lesions often remained unopacified. In multinodular tumours some nodules were heavily stained while others contained little or no contrast medium. In small tumours there was a more uniform distribution. In large tumours, those areas where there are large arteries (and slow flow) contained little or no lipiodol. There was also no consistent match of areas of angiographic blush with lipiodol deposition. The lipiodol patterns were poorly shown by CT when compared with high resolution films taken on a mammography unit. We conclude from this study that lipiodol on its own as an embolic agent or as a chemotherapeutic carrier has great limitations because of its peripheral and otherwise haphazard distribution in large tumours. However, such treatments might be more effective in small tumours where a greater concentration of lipiodol is likely. Nevertheless, lipiodol staining of tumours remains a useful diagnostic aid as small HCC can be difficult to visualize both on arteriography and conventional CT.

Adult↗
PubMed1989

Therapeutic embolization of pulmonary arteriovenous malformation.

A 49-year old man presented with recurrent transient ischaemic attacks and a pulmonary arteriovenous malformation (PAM) was found in his lower left lobe. Left lower lobectomy was performed, and the attacks ceased. However, 18 months later, a fresh PAM was detected in the right lower lobe. In order to avoid further lung resection, therapeutic embolization with metal-dacron coils and gelfoam was performed, resulting in complete occlusion of the PAM. The patient remained well at follow-up 6 months later. Therapeutic embolization is an effective alternative to surgery in the treatment of PAM, especially in the presence of multiple lesions when it is important to conserve functional lung tissue.

Arteriovenous Malformations↗
PubMed1976

Hematologic values for free-ranging urban gray squirrels (Sciurus c carolinensis).

Gray squirrels (Sciurus carolinensis carolinensis) (N=180) from Jacksonville, Fl, were examined for hematologic values: erythrocyte sedimentation rate, packed cell volume, hemoglobin (Hb) concentration, erythrocyte and leukocyte counts, differential leukocyte counts, blood platelet counts, Hb electrophoresis, and erythrocyte fragility. Results were compared by age and by sex of the squirrels and by month of capture.

Animals↗
PubMed1976

Electrophoretic separation of serum proteins from gray squirrels.

Serum proteins of gray squirrels were electrophoretically separated into 7 fractions as compared with the 5 fractions obtained from human serum. The mobility of the albumin fraction was approximately the same for both human and squirrel serums. The prealbumin fraction did not vary significantly in the percentage for squirrels bled at different times of the year. Immunoelectrophoresis patterns showed squirrel serum had a small number of fractions with the same antigenic characteristics as human serum.

Animals↗
PubMed1975

Laboratory screening of hemoglobinopathies.

A procedure for the laboratory screening of hemoglobinopathies is described. The procedure employs hemoglobin electrophoresis followed by solubility testing to confirm presence of sickling hemoglobins. All initial screening tests are carried out on whole blood specimens collected on filter paper. The use of filter paper facilitates collection and results in considerable saving in time and mailing cost. The results of the first year screening confirm the findings of earlier studies that blood specimens collected on filter paper are satisfactory for electrophoresis and solubility tests. All tests are relatively easy to perform using readily available commercial reagents. The procedure is particularly suitable for public health laboratories in carrying out hemoglobinopathy screening programs.

Electrophoresis, Agar Gel↗
PubMed1975

The presence of hemoglobin S and C Harlem in an individual in the United States.

The first reported case of hemoglobin S and C Harlem in an individual is described. The patient, a 35-yr-old female, had numerous crises during adolescence and early adulthood, but these occurred more infrequently as she grew older. Chemical evidence is presented for the characterization of both variant hemoglobins. The clinical course of this individual with Hb S in combination with Hb C Harlem appears to be similar to that for persons with sickle cell anemia.

Adult↗