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Biomedical subjects

H D Chen

Publications and source records attributed to H D Chen.

At least 37 records · Page 2Linked to original sources
PubMed1994

A semi-automated method for edge detection in the evaluation of left ventricular function using ECG-gated single-photon emission tomography.

Thallium-201 gated single-photon emission tomography (GSPET) of myocardium was performed at rest in 18 patients. Images were reconstructed to obtain end-diastolic (ED) and end-systolic (ES) images. The endocardial and epicardial edges of the left ventricle (LV) for the ED and ES images were defined for the mid-ventricular images of the short-axis slices, using a semi-automated method. LV wall thickness was measured for ED and ES images at 10 degrees intervals. Mean LV thickness was derived as the mean of the LV thickness for the three mid-ventricular slices. The systolic thickening (ST) was derived as: mean LV thickness (ES)--mean LV thickness (ED). The systolic thickening ratio (STR) was defined as: ST/mean LV thickness (ED). LV cavity area was measured. The dilation ratio (DR) was defined as: [mean cavity area (ED)--mean cavity area (ES)]/mean cavity area (ED). LV ejection fraction (LVEF) was estimated using technetium-99m gated blood pool study. There was a linear correlation between LVEF and ST (r = 0.85), LVEF and STR (r = 0.77) and LVEF and DR (r = 0.81). There was a strong correlation (r = 0.85) between regional STR and regional percent count increase in 52 segments which did not have perfusion defects. As well as for the evaluation of myocardial perfusion, GSPET images can be of use for the assessment of LV function using an appropriate method for LV edge detection.

Algorithms↗
PubMed1993

Familial medullary thyroid carcinoma: report of three cases in a family.

Familial medullary thyroid carcinoma is a distinct clinical entity in which early diagnosis by screening of family members for elevated calcitonin levels can be useful. A 33-year-old female was hospitalized because of an enlarging left thyroid mass. Resected thyroid showed medullary thyroid carcinoma. Her mother had received a total thyroidectomy due to the same disease 10 years previously, and her younger brother had an elevated basal calcitonin level of 468 pg/mL when the index case was diagnosed. The younger brother was advised to undergo surgery; a total thyroidectomy also revealed medullary thyroid carcinoma. There was no evidence of multiple endocrine neoplasia in the family. Recognition of new cases by screening with a basal or provocative test in families of patients with medullary thyroid carcinoma should be mandatory.

Adult↗
PubMed1991

Usefulness of Tl-201 SPECT imaging in evaluation of left ventricular hypertrophy and dilation in patients with previous myocardial infarction.

Using short axis slices of Tl-201 myocardial SPECT images, total left ventricular (LV) mass, perfused LV mass, defect size, defect mass, ratio of total LV area to cavity area (T/C), ratio of radius of total LV area to radius of cavity area (TR/CR), and ratio of wall thickness to radius of cavity area (W/R) were obtained. The left ventricular ejection fraction (LVEF) was calculated using blood pool imaging studies. A total of 33 patients with old myocardial infarctions were studied. The patients were divided into group 1 (n = 16) with no history of heart failure, and group 2 (n = 17) with a history of heart failure. The LVEF (P less than 0.001), T/C (P less than 0.005), TR/CR (P less than 0.005) and W/R (P less than 0.001) were significantly lower, while the total LV mass (P less than 0.001) and perfused LV mass (P less than 0.01) were significantly higher in group 2. In the whole group of 33 patients, there was inverse linear correlation between the total LV mass and LVEF (r = -0.82), perfused LV mass and LVEF (r = -0.67), and defect mass and LVEF (r = -0.59). There was linear correlation between W/R and LVEF (r = 0.64). Nonlinear correlations were found between T/C and LVEF (r = 0.81) and TR/CR and LVEF (r = 0.80). Tl-201 myocardial SPECT imaging is useful for the evaluation of LV hypertrophy and cavity dilation in patients with previous myocardial infarction.

Adult↗
PubMed1991

Major histocompatibility complex restriction and cross-priming of H-Y antigen in rats.

Although female rats can be sensitized to H-Y-incompatible male skin isografts following exposure to MHC-incompatible male lymphoid cells, these cells are not as effective as MHC-compatible male cells. Evidence is presented that the effectiveness of the MHC-incompatible cells is a consequence of crosspriming and that such crosspriming only occurs if these cells are rejected.

Animals↗
PubMed1991

Expression of OKM5 antigen on keratinocytes in some dermatoses.

Employing an avidin-biotin complex immunoperoxidase technique, it was found that there was OKM5 but no OKM1 antigen expression on the keratinocytes of the upper epidermis from all the studied specimens of seborrheic keratosis, verrucous nevus, Bowen's disease, BCC, SCC, MM, lichen planus, psoriasis vulgaris, condyloma acuminatum, and sporotrichosis as well as in two of eight cases of nevus pigmentosus. Our findings indicate that OKM5 antigen expression on epidermal keratinocytes is usually associated with dermal infiltration. It is assumed that human keratinocytes in cutaneous lesions, like the OKM1- OKM5+ monocyte/macrophage lineages, might play certain roles in immune responses and possibly function as antigen-presenting cells.

Adolescent↗
PubMed1991

Reactivity of monoclonal antibody OKM5 with sebaceous carcinoma.

Two cases of sebaceous carcinoma (SC), as well as epithelial tumours, melanoma, and lymphoma, were examined using immunoperoxidase and a panel of monoclonal antibodies on cryostat sections. The results showed that, whereas all SC cells in both cases reacted strongly with monoclonal antibody OKM5, other tumour cells (except juvenile xanthogranuloma cells) did not. The pagetoid cells within the epidermis of SC also reacted with OKM5 antibody. Although the nature of the phenomenon merits further study, this reactivity, or cross-reactivity, might possibly aid diagnosis of SC.

Adenocarcinoma↗
PubMed1991

Change of circulating thyroid autoantibody titers in Graves' hyperthyroidism after antithyroid drugs therapy.

Parallel measurements of circulating thyroglobulin (Tg), microsomal [TPO(mic)] and TSH-receptor antibodies [TSH-R(rr)] were performed in 30 cases of Graves' hyperthyroid patients who received antithyroid drug (ATD) therapy for 2.8 +/- 1.7 years (range: 0.5-5.0 years). Before ATD therapy, positive Tg, TPO(mic) and TSH-R(rr) antibodies were found in 33.3%, 83.3% and 86.7% of our patients with Graves' disease, respectively. The titers of Tg and TPO(mic) antibodies remained unchanged in most patients after ATD treatment. However, the TSH-R(rr) antibody titers decreased in 46.7%, elevated in 26.7% and unchanged in 26.7% after ATD therapy. Six cases got long-term remission. Measurements of Tg and TPO antibodies have no value in forecasting the outcome of the disease. The change of circulating TSH-R(rr) antibody from positive to negative is more predictive of remission after ATD therapy than the decrease of thyrotropin-binding inhibiting immunoglobulin index only. However, the former change indicating a persistent remission is not certain.

Adult↗
PubMed1990

[Effect of topical fluoridation on post-radiation caries in patients with head and neck cancer].

Post-radiation caries, a rapidly progressing and highly destructive type of dental caries, is one of the most common post- radiation complications in patients with head and neck cancer. Topical fluoride application has been shown in clinical studies to reduce post-radiation caries in irradiated patients. This study reviewed 148 patients who had received radiation for head and neck cancer. All the subjects received pre-radiation dental care. After radiation, the first group consisted of 53 patients who were under regular 3 months dental recall and received topical fluoride applications. The second group consisted of 95 patients who did not return for regular dental recall. Result from clinical examination and bitewing radiographs revealed that the caries indexes were 7% and 31% for the first and second groups, respectively. Chi-Square test showed significant difference between the two groups (P value less than 0.005). Regular topical fluoride application is valuable in reducing dental caries after radiation for head and neck cancer.

Administration, Topical↗
PubMed1990

[Evaluation of effects of dust prevention in the principal tungsten mines in Jiangxi].

An evaluation of the effects of dust prevention in the Jiangxi tungsten mines has been carried out. The rate of silicosis morbidity in most mines was under 1%. Up to 1983, the rate in individual mines is 1.95%. According to the data from those mines, the forecasting of cumulative probability of morbidity of mine workers having been in contact with dust for 30 years is up to 7.5%. From those data, the authors suggest that the maximum permissible concentration of dust should be 1.0 mg/m3 in the mines with concentration of silicon dioxide dust over 70%.

Dust↗
PubMed1989

Occurrence of Langerhans cells and expression of class II antigens on keratinocytes in malignant and benign epithelial tumors of the skin: an immunohistopathologic study with monoclonal antibodies.

We used an avidin-biotin complex immunoperoxidase technique with various monoclonal antibodies to determine Langerhans cell densities, class II antigen expression on keratinocytes, and phenotypes of other infiltrating cells in several malignant and benign epithelial tumors of the skin. Our observations indicate (1) there are few Langerhans cells in nests of basal cell carcinoma and squamous cell carcinoma; (2) there are increased Langerhans cell densities in seborrheic keratoses, verrucous epidermal nevus, and Bowen's disease; (3) there is an expression of class II molecules on the keratinocytes and cancer cells of basal cell carcinoma, squamous cell carcinoma, Bowen's disease, seborrheic keratosis, and verrucous epidermal nevus; and (4) there is a netlike staining of the keratinocyte surface with OKM5 in the epidermal lesion of seborrheic keratosis, verrucous epidermal nevus, and Bowen's disease, as well as in the epidermis adjacent to the basal cell carcinoma and squamous cell carcinoma nests.

Adolescent↗
PubMed1987

Influence of the major histocompatibility complex (MHC) on the response to and expression of H-Y in rats.

The influence of the major histocompatibility complex (MHC) on the survival of H-Y-incompatible skin grafts in rats has been determined by challenging normal and previously sensitized females of various isogenic and congenic strains with male trunk or ear skin isografts. The MHC's influence on the potency of H-Y has also been evaluated by determining the survival of male parental strain ear skin grafts on sensitized (with F1 hybrid male cells) F1 hybrid females of two different MHC congenic strains. The results indicate that, as in mice, the MHC has a dual affect on H-Y; it is involved in determining the ability of females to respond to the antigen as well as influencing its potency.

Animals↗