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Biomedical subjects

T W Chang

Publications and source records attributed to T W Chang.

191 records · Page 11Linked to original sources

An HTLV-III peptide produced by recombinant DNA is immunoreactive with sera from patients with AIDS.

Human T-cell lymphotropic retrovirus type III (HTLV-III), also called lymphadenopathy-associated virus (LAV), has been identified as the aetiological agent of acquired immune deficiency syndrome (AIDS). The sera of most patients with AIDS or AIDS-related complexes, and of asymptomatic individuals infected with HTLV-III, contain antibodies against antigens of HTLV-III. The characterization of these antibodies and their corresponding viral antigens is important not only for understanding immunity against HTLV-III and the pathology of AIDS, but also for the development of diagnostic methods and preventive vaccine for AIDS. Following the successful establishment of a long-term T-cell line permissive for HTLV-III replication, large quantities of virus have been produced, facilitating the purification of viral proteins and the development of mouse monoclonal antibodies against several viral antigens. More recently, the structure of HTLV-III proviral DNA has been elucidated. We now report the production, by genetic engineering methods, of a peptide encoded by a gene segment of HTLV-III. A 1.1-kilobase (kb) EcoRI DNA segment from an isolate of HTLV-III was inserted into a lpp and lac promoter-coupled expression vector, pIN-III-ompA. Escherichia coli transformants of this plasmid produced a peptide of relative molecular mass (Mr) 15,000 (15K) which was strongly immunoreactive with anti-HTLV-III antibodies present in sera from AIDS patients. Lysates of the clones expressing this 15K peptide inhibited the reactivity of the p31 virion protein with AIDS sera, suggesting that it is a fragment of the viral p31 protein. The peptide reacted with sera from all 20 AIDS patients but none of the 8 normal controls tested. These results suggest that the peptide may be useful for detecting anti-HTLV-III antibodies in blood samples.

Acquired Immunodeficiency Syndrome↗

Effect of bismuth subsalicylate on Clostridium difficile colitis in hamsters.

The therapeutic effect of bismuth subsalicylate (BSS, Pepto-Bismol) in Clostridium difficile colitis was studied in golden Syrian hamsters. C. difficile was fed to the hamsters by orogastric intubation 2-3 days after their arrival. Clindamycin (1.5 mg per animal) was given intraperitoneally 4 days later. Twenty-four hours after challenge with clindamycin, animals were given BSS at dosages of 5, 10, and 15 mg twice daily for 5 days by orogastric intubation. Controls included untreated animals and those given 5 mg of vancomycin once daily by intubation. Delay in the time of death was observed in all BSS-treated animals and was statistically significant on days 4-6 in those receiving 15 mg twice daily. Vancomycin produced a greater delay in death than did BSS. Our study suggests that BSS at a dosage of 15 mg twice daily has some therapeutic effect on C. difficile colitis in hamsters.

Animals↗

Genital herpes: Treatment with methylene blue and light exposure.

Fifty-six patients with genital herpes were treated by photodynamic inactivation of herpesvirus by methylene blue (36 patients), proflavine (101 or neutral red (10). The first 35 patients were randomly selected for treatment with one of the three dyes. All the others were initially treated with methylene blue. The disease was temporarily eradicated in about 70% of instances by exposure of the lesions to light plus topically applied methylene blue, neutral red or proflavine. Relapses, however, were not prevented or appreciably reduced.

Acridines↗

Diagnosing invasive cystic hypersecretory duct carcinoma of the breast with fine needle aspiration cytology. A case report.

BACKGROUND: Cystic hypersecretory duct carcinoma (CHC) of the breast, first described in 1984, is a rare variant of duct carcinoma. Histologically it is characterized by the formation of dilated ducts and cysts containing an eosinophilic secretory product resembling thyroid colloid. The lining epithelium of the cysts atypically proliferates to form intraductal carcinoma. Only four cases of invasive cystic hypersecretory carcinoma have been reported. CASE: We present a case of invasive CHC with tumor emboli in many lymphatic spaces and axillary nodal metastases. The lesion was also evaluated by fine needle aspiration. Direct smears with Papanicolaou stain were highly cellular and had abundant, intensely staining, orange-to-gray-green thyroid colloid-like material. Epithelial cells, showing a variety of cellular patterns, were indistinguishable from usual ductal carcinoma cells. These cytologic findings may be characteristic enough to suggest cystic hypersecretory carcinoma. CONCLUSION: The cytologic features of CHC are distinctive and correlate with histology. This was the first presentation of colloidlike secretory material in cytologic material with Papanicolaou stain in such a case. Invasive CHC tends to have aggressive behavior. Cystic hypersecretory hyperplasia coexisted in this case.

Adult↗

Fine needle aspiration cytology of malignant phyllodes tumor with liposarcomatous stroma of the breast. A case report.

BACKGROUND: Liposarcoma arising within a phyllodes tumor is extremely rare. To the best of our knowledge, a malignant phyllodes tumor with liposarcomatous stroma diagnosed by fine needle aspiration (FNA) has not been reported before. CASE: A 39-year-old female had a malignant phyllodes tumor with liposarcomatous stroma diagnosed by FNA cytology. Two subtypes of liposarcomatous stroma, including lipomalike differentiated and myxoid, were found in the aspirates. The cytologic findings were very representative of the histologic features. CONCLUSION: It is very important to recognize the cytologic features of such rare tumors. An accurate diagnosis preoperatively by FNA permits better therapy planning.

Adult↗

Inhibition of antigen-specific IgE production by antigen coupled to membrane IgE peptide.

The membrane IgE peptide (MEP) encompassing 20 amino acids proximal to the C terminus of membrane IgE molecules, and secretory IgE peptides (SEP), spanning CH epsilon 1 to 4 domain were synthesized according to IgE genomic and cDNA sequences. Inhibition of anti-KLH and anti-BGG IgE, but not IgG responses was observed in mice treated with MEP-protein but not SEP-protein conjugates in complete/incomplete Freund's adjuvant. Only IgE responses directed toward proteins to which MEP was conjugated, were inhibited, while IgE responses to a concomitantly injected, unrelated antigen were not. Inhibition of antigen-specific IgE was also not correlated with levels of anti-MEP or anti-IgE antibodies, moreover, levels of total IgE remained comparable among mice treated with MEP-protein conjugates, native or glutaraldehyde-modified protein carriers. This observation may have significant import on future design of IgE immunotherapy. Treatment of MEP conjugated allergens prevents formation of IgE-anti-IgE complexes because the MEP sequence is absent from the secretory IgE.

Amino Acid Sequence↗

Bezoar manifested with digestive and biliary obstruction.

BACKGROUND/AIMS: Gastrointestinal obstructions caused by bezoars are uncommon but are encountered with increasing frequency in general surgery. METHODOLOGY: We made a retrospective review of 30 cases treated in the National Cheng Kung University hospital between July 1988 and December 1994. RESULTS: Fourteen patients had either prior gastric surgery (9) or peptic ulcer disease (5) and were categorized as group I. The remaining 16 patients without above conditions were categorized as group II; and seven of them had history of ingestion of Pho Pu Zi (Cordia dichotoma Frost. f.), three had food bolus ingestion, two had diverticulum, two had adhesion and the remaining two had no significant features. Two patients, who received endoscopic removal of gastric bezoar and subsequently developed bowel obstruction, needed operation. Sixteen of 30 who underwent operation within 24 hours after arrival, recuperated uneventfully and most were discharged within a week. Eleven patients who received operation after 24 hours resulted in prolonged hospitalization in 9 and death in two. Re-operation was performed in one case for the recurrence of obstruction by the residual bezoar. CONCLUSION: Dietary factors (Pho Pu Zi or bolus ingestion), and gastrointestinal (GI) anatomical lesion (diverticulum or adhesion) are the profound etiologies for formation of bezoars in cases without previous gastric surgery. On the other hand, gastric factors (previous ulcer surgery or peptic ulcer) play a major role even after ingestion of nonspecific high fiber diet. Early diagnosis, surgical intervention without delay and thorough exploration of the entire GI tract are essential for good postoperative results.

Adolescent↗