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Biomedical subjects

C H Chang

Publications and source records attributed to C H Chang.

At least 631 records · Page 35Linked to original sources
PubMed1982

The surface morphology and ultrastructure of renal arterial smooth muscle cells in patients with renovascular hypertension.

The surface and internal ultrastructure of renal arterial smooth muscle cells were investigated in 3 patients with renovascular hypertension. The most characteristic features of the surface pathology in hypertrophied smooth muscle cells consisted of various degrees of surface defects, including both extensive loss of surface details and an irregular thickening and disruption of the basement membrane, which was widely separated from the plasma membrane by a clear space. Ultrastructural changes include the appearance of highly lobulated nuclei, multinucleation, disorganization of myofilaments and increased numbers of rough-surfaced sarcoplasmic reticulum and mitochondria, which are usual manifestations of cellular hypertrophy. These results suggest that ionic movement across the cell membranes, particularly of Ca2+, is probably abnormal in hypertrophied smooth muscle cells. This may result in functional disorders of hypertensive arteries.

Adolescent↗
PubMed1982

Scanning electron microscopy of human lungs in various forms of heart disease.

The surface morphologic features of the lung obtained from 21 patients with various forms of heart disease were investigated by scanning electron microscopy, with particular emphasis on the correlation between the surface pathology and cardiopulmonary hemodynamics. There were almost no pathologic findings on the bronchiolar and alveolar surfaces in patients with normal pulmonary arterial wedge pressure (PAWP). The characteristic changes of the surface morphology of the lung parenchyma in patients with abnormal elevation of PAWP included various degrees of desquamating loss of the bronchiolar epithelium associated with inflammatory cell infiltration and fibrotic changes and focal epithelial disruption of the individual alveoli which often extended to involve the surface of the entire alveoli with perforated rupture of the alveolar septa. The severity of abnormal surface morphologic findings of the lung seemed to correlate to the degree of PAWP. From our results it is concluded that chronic lung congestion plays a major role in the pathogenesis of the surface pathologic changes of the lung in patients with heart disease of various etiologies. Our findings may provide a clearer understanding of the structural and functional relationship of congestive lung and a clinical explanation for pulmonary manifestations in patients with chronic congestive heart failure.

Adolescent↗
PubMed1982

Computed tomographic mammography using a conventional body scanner.

The technique for computed tomographic (CT) examination of the breasts using a conventional body scanner is described, and experience with 67 patients is reported. In the diagnosis of both malignant and benign breast lesions, the results with a body scanner were equal to those of a dedicated CT/M mammographic unit. Although the CT study of the breast cannot replace conventional mammography in screening or in routine diagnostic workup, the unique capability of demonstrating both anatomic changes and increased iodide concentration in a cancer provides many advantages over conventional mammography. CT mammography appears to have the capability to detect breast cancers that are occult to other methods. Indications for a CT study of the breasts are: (1) clinically suspected breast cancer, especially with a mammographically occult lesion; (2) questionable mammographic findings, including microcalcifications, tumor shape, architectural distortion, and uncertain lesion location; and (3) evaluation of postbiopsy or postlumpectomy breast cancers when a primary irradiation therapy is contemplated. Breast CT also appears to be a valuable diagnostic tool in searching for a second primary breast cancer, follow-up study of postirradiation of breast cancer, followup study for postmastectomy patients, and screening procedure for genetically high-risk patients, especially those with dense breasts.

Adult↗
PubMed1982

Studies on the anaemia of Asian patients with chronic renal failure undergoing regular haemodialysis.

Studies of ferrokinetics, iron status and serum erythropoietin levels were undertaken in 28 Asian patients on RDT as they appeared to be more anaemic and to have a poorer response to treatment than their Western counterparts. The main aetiological factor seemed to be inadequate bone marrow function which tended to be worst in those who had been on dialysis the longest. In addition it is possible that there was also a relative lack of erythropoietin. Dietary factors and iron deficiency were not important. The possible roles of a progressive accumulation of a toxic factor, or of relative underdialysis in patients who were profoundly uraemic prior to the institution of regular haemodialysis, are discussed.

Anemia↗
PubMed1981

Computed tomographic mammography. Diagnosis of mammographically and clinically occult carcinoma of the breast.

If breast cancer can be detected early, while it is still localized and before it can be palpated, the prognosis for cure is excellent. Heretofore, conventional mammography has been the only means available to detect cancer at such an early stage. Two cases of minimal breast carcinoma measuring less than 5 mm in diameter have been detected and correctly diagnosed using computed tomographic mammography (CT/M). Both cases occurred in fatty breasts and were clinically and mammographically occult. These cases demonstrate the value of CT/M in the diagnosis of minimal breast carcinoma that would have been missed otherwise.

Adult↗
PubMed1981

Epithelial lesions of bladder mucosa following ureteral reimplantation.

We report on 3 children who underwent ureteral reimplantation. Postoperatively, each patient had persistent, irritative, lower tract symptoms and continuous or recurring urinary infections, with or without gross hematuria. Because of these symptoms cystoscopy was done in 2 children and the third child under went repeat ureteral reimplantation because of persistent vesicoureteral reflux. At operation single or multiple hyperplastic, sessile lesions of the urothelium, not evident at the time of initial ureteral reimplantation, were discovered in each child. Histologically, these lesions showed proliferative and metaplastic glandular epithelial changes. Treatment consisted of transurethral fulguration and long-term antimicrobial medication plus partial cystectomy and topical intravesical chemotherapy for recurrent lesions in 1 child. The etiology of these epithelial lesions, although uncertain, is believed to be a response to long-standing inflammation.

Adolescent↗
PubMed1981

Lateral mobility of erythrocyte membrane proteins studied by the fluorescence photobleaching recovery technique.

Erythrocyte membrane peripheral and integral proteins have been isolated and purified, and the lateral diffusion of these proteins in a well-defined phospholipid bilayer matrix (dimyristoylphosphatidylcholine) has been studied by fluorescence photobleaching recovery measurements. Our own instrument for the recovery measurements is described and some data for lipid diffusions are compared with those previously reported by other investigators. The peripheral proteins (spectrin and band 4.1) diffuse rapidly on the lipid membrane in its fluid phase. The diffusion constant of approximately 5 x 10(-8) cm2 . s-1 (30 degrees C) was only a little smaller than that for lipid diffusion. The diffusion was greatly slowed down when the host lipid matrix became solid. The integral protein band 3 also diffuses rapidly in the fluid membrane. The diffusion constant of 1.6 x 10(-8) cm2 . s-1 (30 degrees C) was smaller than those for lipids and for the peripheral proteins. The lateral motion is compatible with diffusion of a cylinder with radius 3 nm in a two dimensional matrix with an inner viscosity of 2 poises and an inner thickness of 4 nm. The band 3 lateral motion was restricted by binding of the cytoskeletal component proteins (ankyrin, spectrin, actin, and band 4.1) to the reconstituted membranes. The diffusion constant decreased to half. The results provide a basis for the elucidation of transmembrane control mechanisms in more complex cellular systems.

Anion Exchange Protein 1, Erythrocyte↗
PubMed1981

Preoperative and postoperative echocardiographic studies of pulmonic valvular endocarditis.

The echocardiographic manifestations of pulmonic valvular endocarditis in a patient with underlying heart disease consisting of a ventricular septal defect and infundibular stenosis are reported. The abnormal shaggy echoes observed on the pulmonic valve were confirmed to be vegetations based on surgical and pathologic findings. This was further proven by the disappearance of the shaggy echoes after surgical excision of the vegetations. We conclude that echocardiograms can detect the presence and disappearance of pulmonic valvular vegetations, which may be of aid in the diagnosis of pulmonic valvular endocarditis.

Adult↗
PubMed1981

Modulation of reproductive hormones by suckling and exogenous gonadal hormones in young beef cows post partum.

Plasma concentrations of LH, prolactin, progesterone and oestradiol-17 beta were measured during post-partum anoestrus in 12 young beef cows (6 suckling, 6 not suckling). A progesterone-releasing intravaginal device (PRID) was inserted on Day 60 post partum for 12 days in 3 cows in each group. Two of three suckling cows exhibited oestrus within 2 days after PRID removal (Day 73) whereas none of the untreated cows showed oestrus before Day 93. Five of six non-suckling cows showed oestrus before Day 60. Intensive bleeding periods on Days 45, 58, 70 and 72 provided plasma samples for LH and prolactin measurements. Suckling did not affect the LH baseline or the number of LH spikes but did decrease the mean value of the spikes; all three of these characteristics were increased for prolactin. The number of prolactin spikes and the length of anoestrus in suckling cows were correlated (r = +0.87, P less than 0.05) as were mean basal LH level and length of anoestrus (r = -0.89, P less than 0.05). A decrease in plasma LH occurred in suckling and non-suckling cows during the period (Days 60-72) they were treated with gonadal hormones.

Anestrus↗
PubMed1981

The surface morphology of the infundibular muscle in patients with tetralogy of fallot.

The surface morphology of the infundibular muscles obtained from open heart surgery was investigated in 10 patients with tetralogy of Fallot. Various degrees of abnormal surface morphological changes were observed from the endocardium to the myocardium. In the endocardium striking proliferation of the endothelial cells was usually accompanied by focal loss of the endothelium with fibrotic change. Based on the characteristic alterations of the surface morphology 4 different groups of myocardial cells could be identified: normal myocytes, defective myocytes, sclerotic myocytes, and necrotic myocytes. Because intact surface morphology is responsible for integrated cellular function these pathological findings observed on the surface morphology of the endocardium and myocardium can provide a valuable reference to further understanding of functional disorders of the infundibular muscle in patients with tetralogy of Fallot.

Adolescent↗