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Biomedical subjects

J C Chang

Publications and source records attributed to J C Chang.

At least 109 records · Page 6Linked to original sources
PubMed1994

CD8+ T cells in psoriatic lesions preferentially use T-cell receptor V beta 3 and/or V beta 13.1 genes.

Psoriasis is an inflammatory skin disorder characterized by epidermal keratinocyte hyperproliferation in association with a cellular infiltrate. There is evidence that activated T cells play a role in psoriatic plaque formation. We examined the T-cell receptor beta-chain variable gene segment (V beta) use of epidermal T cells in shave biopsies of psoriatic lesions. Our results show increased expression of V beta 3 and/or V beta 13.1 messages in the CD8+, but not CD4+, T cells in the lesions of a majority of patients studied. Sequence analysis of complementarity-determining region 3 (CDR3) of these two V beta genes from the skin demonstrated monoclonality or marked oligoclonality. A second biopsy from the same or different lesions, performed 3.5-8 months later in four patients, again revealed increased V beta 3 and/or V beta 13.1 expression and clonality. Moreover, in three of the four patients, the same V beta CDR3 rearrangement was found in both biopsies, although there was no V beta CDR3 homology between patients. In two patients in which V beta 3 and/or V beta 13.1 was not increased, an increase in V beta 17 gene use and clonality was found. The clonality of V beta sequence data indicates these cells are recruited and expanded in situ. The persistence of V beta 3-and/or V beta 13.1-bearing CD8+ T cells in lesions that did not undergo resolution suggests their role as effector cells rather than as regulatory cells.

Adult↗
PubMed1994

Coffee-associated osteoporosis offset by daily milk consumption. The Rancho Bernardo Study.

OBJECTIVE: To describe the association of lifetime intake of caffeinated coffee, in cup-years, to bone mineral density (BMD) of the hip and spine in postmenopausal women; and to determine the effect of regular milk intake on this association. DESIGN: Women from an established epidemiologic cohort had measures of BMD and gave a medical and behavioral history that included caffeinated coffee and daily milk intake between the ages of 12 and 18 years, 20 and 50 years, and 50 years of age and older. SETTING: A community-based population of older women, Rancho Bernardo, Calif. PARTICIPANTS: All 980 postmenopausal women aged 50 to 98 years (mean age, 72.7 years) who participated between 1988 and 1991. MAIN OUTCOME MEASURES: Bone density at the hip and lumbar spine measured by dual energy x-ray absorptiometry. MAIN RESULTS: There was a statistically significant graded association between increasing lifetime intake of caffeinated coffee and decreasing BMD at both the hip and spine, independent of age, obesity, parity, years since menopause, and the use of tobacco, alcohol, estrogen, thiazides, and calcium supplements. Bone density did not vary by lifetime coffee intake in women who reported drinking at least one glass of milk per day during most of their adult lives. CONCLUSIONS: Lifetime caffeinated coffee intake equivalent to two cups per day is associated with decreased bone density in older women who do not drink milk on a daily basis.

Aged↗
PubMed1994

Serotypes and mating types of clinical strains of Cryptococcus neoformans isolated in Taiwan.

Twenty-one strains of Cryptococcus neoformans isolated from patients in Taiwan were characterized for serotypes and mating types. Slide agglutination test was performed with 8 factor-specific sera (Iatron Company, Japan) to determine the serotypes. Wheat bran agar (WBA) and malt extract agar (MEA, Wickerham) media were used for the mating tests. Twenty of the isolates were of serotype A, and one was serotype B. Except for 2 strains of serotype A, all of the serotype A strains mated with Filobasidiella neoformans var. neoformans, mating type a. The only serotype B strain mated with F. neoformans var. bacillispora mating type a in MEA medium. These data revealed the low prevalence (1/21; 4.8%) of C. neoformans var. gattii in Taiwan, a subtropically located isoland.

Cryptococcosis↗
PubMed1994

Study of efficacies of leukocyte-depleted terminal blood cardioplegia in 24-hour preserved hearts.

To evaluate the effect of leukocyte-depleted terminal blood cardioplegia on prolonged preservation, 41 canine hearts were stored in modified Collins' solution and transplanted heterotopically. Hearts were transplanted soon after harvesting in group 1 and after 24-hour preservation in groups 2, 3, and 4. Blood cardioplegia was applied just before aortic unclamping in groups 3 and 4; group 3 received simple blood cardioplegia and group 4 received leukocyte-depleted cardioplegia. The percentage of the preload recruitable stroke work and diastolic compliance after transplantation compared with the preharvesting value in group 4 did not differ from those in group 1, but the percentage of the preload recruitable stroke work in groups 2 and 3 was significantly lower than that in groups 1 and 4. The percentage of diastolic compliance in groups 2 and 3 was significantly higher than that in groups 1 and 4. Coronary blood flow 40 minutes after aortic unclamping in group 4 did not differ from that in group 1, but was significantly higher than the blood flows in groups 2 and 3. Significant production of malondialdehyde was detected during terminal blood cardioplegia and 10 minutes after aortic unclamping in groups 2 and 3, but never in groups 1 and 4. After leukocyte-depleted terminal cardioplegia, the myocardial adenosine triphosphate content increased to the preharvesting value in group 4. Our results suggest that leukocyte-depleted terminal blood cardioplegia may be effective in replenishing the energy-depleted myocardium and reducing reperfusion injury, resulting in adequate cardiac function.

Adenosine Triphosphate↗
PubMed1994

Composite denture teeth made on a removable partial metal framework.

Most denture teeth and denture bases are made of polymethyl methacrylate, which does not chemically bond with a metal framework. The absence of a chemical bond leads to weak retention and high microleakage between the resin and metal interface. With a 4-META bonding agent, a chemical bond that increases retention and decreases microleakage can be created between the composite and the metal interface. This article describes a method for making composite denture teeth with a 4-META bonding agent. It can be done without costly equipment and can also be used to repair acrylic resin denture teeth.

Composite Resins↗
PubMed1994

A soldering index made with 4-META adhesive resin.

Soldering indexes are most often made of fast-setting impression plaster or autopolymerizing resin. Lack of adhesive bonding between these materials and the casting requires the use of a bulky index to support the fixed partial denture components. The advent of adhesive resins improves the quality of the index and simplifies the procedure. A procedure for making a soldering index with 4-META adhesive resin is described that involves direct bonding of the resin to the metal castings. This procedure is accurate, simple, and time-saving. It can be used inside or outside the mouth, in prosthodontic or implant dentistry.

Acrylic Resins↗
PubMed1994

SV40 T antigen directed by a powerful erythroid enhancer-promoter produced sarcomas and pancreatic tumors but not erythroid-specific tumors in transgenic mice.

We have expressed the simian virus 40 (SV40) large T antigen oncogene in erythroid tissues of mice to test its ability to immortilize erythroid cells. A transgene construct was built in which the SV40 large T antigen structural gene was linked to erythroid-specific enhancer and promoter sequences. The enhancer employed was the human beta-globin family microlocus control region, and the promoter sequences were derived from the human beta-globin promoter. Transgenic mice were generated and they expressed T antigen in the bone marrow and spleen cells. Yet, no hematopoietic neoplasia arose in these mice. Instead, after a lag period of 2-6 months, the mice developed soft tissue sarcomas and pancreatic islet-cell tumors that expressed high levels of T antigen.

Animals↗
PubMed1994

Acute lymphoblastic leukaemia following Hodgkin's disease is associated with a good prognosis.

Acute leukaemia, both myeloid and lymphoblastic, in patients treated for Hodgkin's disease (HD) is thought to have a poor prognosis. We report four adults who developed secondary acute lymphoblastic leukaemia (ALL) following chemoradiotherapy for HD. The chromosomal translocation t(4;11) (q21;q23) was found in two patients who received a chemotherapeutic regimen containing the DNA topoisomerase II inhibitor etoposide. Three of the four patients are alive and in unmaintained first remission at 3, 5 and 9 years from diagnosis of ALL, two following autologous bone marrow transplantation. These results suggest that ALL following HD may have a good prognosis when treated aggressively.

Adult↗
PubMed1994

Idiopathic autoimmune hemolytic anemia during pregnancy.

A case of idiopathic autoimmune hemolytic anemia occurring during the third trimester of pregnancy is presented. The hemolytic process was quite severe in the mother but responded to steroid therapy. A healthy baby without evidence of hemolysis was delivered uneventfully through the vagina. We postulate the mechanism of the discuss the clinical picture, management of the disease and the possible effect on the fetus.

Adult↗
PubMed1994

[Drug resistance and plasmid analysis in Pseudomonas aeruginosa].

One hundred and ninety seven strains of Pseudomonas aeruginosa were isolated from urine (59 strains), wound pus (60 strains), sputum (30 strains), stool (30 strains) and eye discharge (18 strains) at Kaohsiung medical College Hospital. These strains were serotyped with antisera against O antigens and tested with twelve different antimicrobial agents. The results showed that the most frequently isolated strains were serotype E (41.1%), followed by serotype B (20.3%), serotype F (10.7%) and serotype L (9.1%). In in vitro susceptibility testing, all isolated strains were resistant to chloramphenicol and tetracycline. Otherwise, these isolates were highly susceptible to ceftazidime (95.4%), enoxacin (89.3%) and piperacillin (87.8%). The isolates from urine exhibited more multiple drug resistance patterns than those of other specimens. When plasmid content was analysed from pseudomonas aeruginosa, only 15.2% (30/197) of isolates carried plasmids. By conjugation, transformation and mobilization experiments, it was shown that 13.3% (4/30) of plasmid carrying strains contained R plasmids.

Chloramphenicol↗
PubMed1994

[Obstruction of the left ventricular outflow tract due to an anomalous muscle bundle and an accessory tissue on the mitral valve associated with mitral stenosis].

This paper details a rare cause of subaortic obstruction, a discrete membrane combined with an anomalous muscle bundle and an accessory tissue on the mitral valve. A 13-year-old boy was referred to our hospital for surgical relief of subaortic obstruction and mitral stenosis. He had received two additional operations, the first was for coarctation of aorta when 5 years old and the second was for discrete subaortic stenosis when 6 years old. Recatheterization at this time revealed an peak systolic gradient of 44 mmHg across the left ventricular outflow tract, and an peak diastolic gradient of 7 mmHg across the mitral valve. An echocardiogram revealed two longitudinally anomalous tissues in the left ventricular outflow tract. Excision of both anomalous tissue and mitral valve replacement were performed. The macroscopic findings and histological reports of the excised specimens showed that one was the accessory mitral valve tissue and another was the anomalous muscle bundle. Intraoperative epicardial echocardiography is beneficial for evaluating the obstructive status of the LV outflow tract before and after excision of the anomalous tissues in this case.

Adolescent↗
PubMed1994

Hemoptysis in a patient with congestive heart failure and pulmonary emboli.

This article reports a case of profuse hemoptysis in pulmonary embolism and reviews the literature. A 74-year-old patient with hypertension and dilated cardiomyopathy was admitted to the hospital for exacerbation of congestive heart failure and hemoptysis. During hospitalization, the patient had hemoptysis of 270 cc during a 24-hour period. Chest radiograph showed bilateral lower lobe infiltration. Fiberoptic bronchoscopy was performed and revealed active bleeding from both lower lobes of the lungs. An endobronchial lesion was not seen, and the patient had an open lung biopsy. Histological examination of the lung tissue revealed an organized thrombus.

Aged↗
PubMed1993

Molecular cloning of rat cytokine synthesis inhibitory factor (IL-10) cDNA and expression in spleen and macrophages.

Rat cytokine synthesis inhibitory factor (IL-10) was cloned. Like mouse and human IL-10 (mIL-10, hIL-10), rat IL-10 exhibits strong DNA and amino acid sequence homology to the open reading frame in the Epstein-Barr virus, BCRFI. The supernatant of COS-7 transfectants with rat IL-10 was found to inhibit the production of IFN-gamma by murine Th1 cells. A probe from the rat IL-10 was used in an RNase protection assay to demonstrate that IL-10 was expressed in LPS-stimulated rat spleen and FACS-purified OX-42-reactive peritoneal macrophages. The production of IL-10 by macrophages, as shown in the current study, suggests that IL-10 may have an autocrine function in inflammation.

Amino Acid Sequence↗
PubMed1993

Rhabdomyosarcoma arising in transgenic mice harboring the beta-globin locus control region fused with simian virus 40 large T antigen gene.

The beta-globin locus control region (LCR) confers a high level of erythroid-specific and copy-number-dependent expression to human globin genes in transgenic mice. Simian virus 40 T (tumor) antigen (Tag) with its own natural enhancer causes choroid plexus tumors in mice. We investigated the effect of the LCR on Tag gene expression, reasoning that mice harboring a LCR-Tag fusion gene might develop hematopoietic malignancies. To test this hypothesis we introduced an enhancerless Tag gene downstream of a LCR cassette into the germ lines of mice. The phenotypes of the transgenic mice depended on the copy number of the transgene. While mice with 1-2 copies matured normally, those with 3-7 copies developed rhabdomyosarcomas in different anatomic sites at high frequency and showed hyperplasia of the pancreatic islet cells which progressed to pancreatic islet tumors. In addition, the mice bearing 7 copies of the transgene had hypoglycemia and were stunted in growth. Mice with more than 10 copies were markedly stunted in growth and died within 2-4 weeks. Tag expression was detected at high levels in the mouse tumors but not in any other tissues, including the hematopoietic cells.

Animals↗
PubMed1993

Occupational risk factors for lung cancer among nonsmoking women: a case-control study in Missouri (United States).

Occupationally related risk of lung cancer among women and among nonsmokers has not been widely studied. A recently conducted population-based, case-control study in Missouri (United States) provided the opportunity to evaluate risk of lung cancer associated with several occupational factors. Incident cases (n = 429) were identified through the Missouri Cancer Registry for the period 1986 through 1991, and included 294 lifetime nonsmokers and 135 ex-smokers who had stopped at least 15 years prior to diagnosis or had smoked for less than one pack-year. Controls (n = 1,021) were selected through driver's license and Medicare files. Risk was elevated among women exposed to asbestos (ever: odds ratio [OR] = 3.5, 95 percent confidence interval [CI] = 1.2-10.0; > 9 yrs: OR = 4.6, CI = 1.1-19.2) and pesticides (ever: OR = 2.4, CI = 1.1-5.6; > 17.5 yrs: OR = 2.4, CI = 0.8-7.0). Risk also was elevated among dry cleaning workers (ever: OR = 1.8, CI = 1.1-3.0; > 1.125 yrs: OR = 2.9, CI = 1.5-5.4). Occupational risks for lung cancer among women merit further study.

Adult↗