Biomedical subjects

D L Cheng

Publications and source records attributed to D L Cheng.

At least 37 records · Page 2Linked to original sources

PubMed1995

LAK cell mediated apoptosis of human bladder cancer cells involves a pH-dependent endonuclease system in the cancer cell: possible mechanism of BCG therapy.

Intravesical bacillus Calmette-Guerin (BCG) is an effective treatment for superficial bladder cancer. However, its mechanism has been only partially elucidated. We studied whether LAK cell killing of human bladder cancer cells occurs via apoptosis (programmed cell death) or necrosis. Fluorescent dye labeled T24 cells were observed to undergo morphologic changes associated with apoptosis in the presence of LAK cells when analyzed under a fluorescence microscope. Furthermore, analysis of the DNA isolated from the cytotoxic assay confirmed that the LAK cell induced death of the T24 cells occurred via apoptosis. By pretreating the LAK cells with antifibronectin antibodies, we were able to significantly inhibit the LAK cell killing of the T24 cells. The percentage of cytotoxicity was reduced from 50% to 13% (p = 0.001), and the apoptotic pattern seen on agarose gel electrophoresis was significantly diminished. There was no significant change in the viability of the LAK cells following treatment with the antibodies. Endonuclease isolation from human bladder cancer T24 cells demonstrated that these cells express a pH-dependent and not a Ca++/Mg++ dependent endonuclease. Significant degradation of a target DNA was observed only in pH 4 to pH 5.6 buffers containing endonuclease from T24 cells and not in pH 6 to pH 8 buffers containing endonuclease from T24 cells. The presence or absence of Ca++/Mg++ in the various pH buffers did not alter the endonuclease activity. Finally, we demonstrated that death of T24 cells can be induced by altering the intracellular pH of the cells to 5.6 or lower with the proton ionophore nigericin. We conclude that LAK cells induce T24 cells to undergo apoptosis and that this process involves the fibronectin molecule present on the LAK cell membrane. Furthermore, the cleavage postulate that, in vivo, LAK cells activated by IL-2 produced by BCG activated CD4+ cells may induce bladder cancer cells to undergo apoptosis. This may partially explain the mechanism whereby BCG achieves its therapeutic effect.

Antibodies↗

PubMed1994

Bacillus Calmette-Guérin interacts with the carboxyl-terminal heparin binding domain of fibronectin: implications for BCG-mediated antitumor activity.

Intravesical bacillus Calmette-Guérin (BCG) has been shown to be an effective treatment for superficial transitional cell carcinoma of the bladder. The mechanisms by which BCG achieves this effect remain unclear. Reports have attributed an important role to fibronectin both in the initial attachment of BCG to bladder surfaces and in the limitation of tumor cell motility. In the present study, using limited protease cathepsin B degradation followed by Western blot analyses with antibodies to various domains of the fibronectin molecule, we showed that BCG appears to bind to fibronectin near the carboxyl terminal and adjacent to the heparin binding domain. Furthermore a 51-chromium release assay with human bladder cancer cell line T24 as target cells and lymphokine activated killer (LAK) cells as effector cells showed that fibronectin was needed for tumor cytotoxicity by the LAK cells. By using antibodies and peptides to various domains of the fibronectin molecule, the heparin binding domain, but not the cell binding domain, carboxyl terminal region, or the amino terminal region of the fibronectin molecule, was identified as essential to tumor cell lysis by the LAK cells. Flow cytometric analysis showed that both peripheral blood lymphocytes and the LAK cells express fibronectin receptors VLA-3, VLA-4 and VLA-5 on their surfaces. However, the numbers of receptors are not significantly different in the two cell populations. We conclude that, by binding near the carboxyl terminal region and adjacent to the heparin-binding domain of the fibronectin molecule, BCG may protect this region of the molecule from tumor proteases, and may thus allow the antitumor activity of the host immune cells to take place.

BCG Vaccine↗

PubMed1994

Conservative treatment of type III renal trauma.

Type III renal injuries, deep cortical lacerations with or without urinary extravasation, have traditionally been managed by exploration and surgical repair. With improved and readily available radiologic imaging modalities such as computed tomography and intravenous pyelography, we propose that the majority of these injuries can be followed expectantly with delayed intervention as needed. The records of 71 patients with both blunt abdominal and penetrating trauma with suspected significant renal injuries were reviewed. Eighteen patients (nine blunt and nine penetrating trauma) with type III injury were identified. Thirteen patients had their renal injuries treated conservatively and three patients underwent immediate surgical repair. Two patients died of associated injuries shortly after arrival at the emergency room. Two of the conservatively treated patients and one who had initial repair needed subsequent intervention, but no renal unit was lost because of delayed intervention. Thus, of the 16 surviving patients with type III injuries, 13 (81%) were successfully managed conservatively without the need for surgical intervention. With the aid of computed tomography, conservative therapy for severely injured kidneys can yield favorable results and save patients from unnecessary exploration and possible renal loss.

Adult↗

PubMed1994

Antibacterial activity of cefepime in vitro.

Cefepime is a new parenterally active fourth-generation cephalosporin which is undergoing in vitro and in vivo evaluations. Using the standard agar dilution method we compared the in vitro activity of this drug with other cephalosporins and ciprofloxacin against clinical isolates of Escherichia coli (98 strains), Klebsiella pneumoniae (99 strains), Acinetobacter spp. (24 strains), Pseudomonas aeruginosa (98 strains), Haemophilus influenzae (108 strains), Staphylococcus aureus (100 strains), Enterococcus spp. (45 strains), Streptococcus pneumoniae (10 strains), Streptococcus pyogenes (group A; 19 strains) and Streptococcus agalactiae (group B; 36 strains). Cefepime showed excellent activity against E. coli and K. pneumoniae, inhibiting 90% of these isolates at 0.12 mg/l. The in vitro activity of cefepime was superior to or comparable to the third-generation cephalosporins tested but was inferior to ciprofloxacin against Acinetobacter spp. and P. aeruginosa. Against H. influenzae, whether or not the strains produced beta-lactamase, its activity was similar to comparable drugs. All 84 isolates of methicillin-susceptible S. aureus were inhibited by 8 mg/l of cefepime whereas, like other cephalosporins, it had little activity against methicillin-resistant S. aureus. Of the 45 enterococci isolates tested, 44.4% were inhibited by 8 mg/l of cefepime. Against streptococci, its activity was superior to any drug tested. This in vitro study indicates that cefepime has the potential to be a valuable agent for the treatment of community- and hospital-acquired cutaneous, respiratory and urinary tract infections.

Cefepime↗

PubMed1994

Azithromycin in the treatment of pneumonia caused by Chlamydia pneumoniae: report of a case.

We report a 67-year-old male with pneumonia in which Chlamydia pneumoniae was identified by serologic studies as the causative agent. After initial treatment failure with amoxicillin + clavulanic acid, pneumonia was successfully treated with the administration of oral azithromycin, 500 mg per day, for three days. Azithromycin is a new macrolide which has a long half-life and superior action to erythromycin. It provides a new and alternative choice in the treatment of Chlamydia pneumoniae infection in the future.

Aged↗

PubMed1994

Streptococcus suis meningitis complicated with permanent perceptive deafness: report of a case.

A 61-year-old pig farmer was found to be suffering from meningitis caused by Streptococcus suis type II. He was successfully treated with intravenous penicillin G but was left with permanent deafness. B-cell lymphoma was also diagnosed one year later. S. suis is a zoonotic pathogen which causes meningitis, septicemia and endocarditis in pigs. Human infection is rare and often presents as meningitis with the sequela of permanent deafness. It has previously been reported in pig rearing countries such as Holland or Hong Kong. This is the second documented case of human meningitis caused by S. suis in Taiwan, which is also a major pig rearing country in Asia. Infections caused by viridans streptococci or other beta-hemolytic streptococci in Taiwan may therefore actually be due to S. suis. Further investigation of the possibility of the underlying deficiency of humoral immunity is warranted.

Agricultural Workers' Diseases↗

PubMed1993

The lung contents of endothelin are altered by thyroid hormone status in rat.

Endothelin-1 (ET-1) is a 21-residue peptide isolated from the conditioned medium of cultured porcine endothelial cells and is widely distributed throughout the body, with relatively high levels in the kidney and lung. Animal studies have revealed that the lung appears to have the largest capacity for ET-1 removal from the blood stream. In this study we have examined the possible influence of thyroid status on immunoreactive endothelin (IR-ET) levels in the plasma and lung of the male rats. 3 weeks after the surgical removal of the thyroid gland from male rats, the IR-ET levels in the lung were reduced by 39%. Similarly, IR-ET levels were decreased 46% in the lung of rats rendered hypothyroid by treatment with 0.1% (w/w) PTU in the drinking water for 30 days, and replacement with daily L-thyroxine (T4) injections (5 micrograms/100 g) prevented this decrease. However, thyrotoxicosis induced by daily L-T4 injections (10 micrograms/100 g) also caused a decrease of the lung IR-ET levels by 49%. Nevertheless, the plasma IR-ET levels are similar in each group. Fast protein liquid chromatography study verified the presence of ET-1 immunoreactivity in both rat plasma and lung tissue extracts. This study demonstrates that euthyroid status is required for the maintenance of physiological concentrations of IR-ET in the lung of male rats.

Animals↗

PubMed1993

Tissue contents of endothelin vary according to thyroid hormone status in rat.

Endothelin-1 (ET-1) is a 21-residue peptide isolated from the conditioned medium of cultured porcine endothelial cells and is widely distributed throughout the body, with relatively high levels in the kidney and lung. In this study we examined the influence of thyroid hormone status on immunoreactive endothelin (ir-ET) levels in the plasma, lung, and kidney tissues of rats. Three weeks after surgical removal of the thyroid gland from male rats, the ir-ET levels in the lung and kidney were reduced by 39% and 42%, respectively. Similarly, ir-ET levels were decreased by 46% in the lung and 45% in the kidney of rats rendered hypothyroid by treatment with 0.1% (wt/wt) n-propylthiouracil (PTU) in the drinking water for 30 days. Replacement with daily L-thyroxine (T4) injections (5 micrograms/100 g) prevented this decrease. However, thyrotoxicosis induced by daily L-T4 injections (10 micrograms/100 g) also caused a decrease of the lung ir-ET levels by 49%, but had no significant effect on the renal ir-ET levels. However, the plasma ir-ET levels were similar in each group. Fast protein liquid chromatography study verified the presence of ir-ET-1 in the plasma and tissue extracts. This study demonstrates that thyroid hormone status affects tissue levels of ir-ET differently and that a euthyroid status is required for the maintenance of physiologic concentrations of ir-ET in the lung of male rats.

Animals↗

PubMed1993

Seroprevalence of Chlamydia pneumoniae in Taiwan.

Chlamydia pneumoniae (TWAR) is a relatively newly discovered respiratory tract pathogen which was first isolated in Taiwan. In order to describe the seroepidemiology of C. pneumoniae in Taiwan, we evaluated 1,085 stored serum samples: 904 from patients, 97 from umbilical cord blood samples, and 84 from medical personnel at the Veterans General Hospital-Kaohsiung, between January 1 and April 30, 1991. Antibodies were determined by the use of a microimmunofluorescence test using elementary bodies of C. pneumoniae AR-39 as antigen. Sera were tested with screening titres of 16 and 512 for immunoglobulin G antibody. The antibody prevalence was found to be 23.1% in young children (6 months to 10 years old), rising to 66.7% in teenagers, and to 96.2% in older age groups. These rates were higher than any reported earlier. The progressively increasing rates of seropositivity found in older individuals indicated a surge of reinfection in these age groups. Only 5 cases were found with micro-IF IgG titres equal to or greater than 512. All were asymptomatic according to the hospital records. In addition to a high prevalence rate in Taiwan, the data also showed high infection rates in teenagers and elderly people.

Adolescent↗

PubMed1993

Acute Q fever: first case report in Taiwan.

A 70-year-old retired fisherman presented with fever, chills and headache for four days. The clinical presentation was mild, including a self-limiting fever, pneumonia and elevated liver enzyme levels. Acute Q fever was proved by a four-fold rise of phase II IgG antibodies. Interestingly, the man denied any animal contact or travelling over the past year. This case may suggest that Q fever should be added to the list of differential diagnoses for acute febrile disease in Taiwan.

Acute Disease↗

PubMed1993

[Chemical constituents of Emilia sonchifolia L. DC].

Five known compounds were obtained from the whole plant of Emilia sonchifolia. By means of chemical and spectral methods, they were identified to be simiral, beta-sitosterol, stigmasterol, palmitic acid and honey acid.

Drugs, Chinese Herbal↗

PubMed1993

Five-year experience of human immunodeficiency virus type 1 national screening program implemented at Veterans General Hospital-Taipei.

From July 1986 through June 1990, 33,199 sera from various risk groups were collected in Veterans General Hospital-Taipei for detection of antibody against human immunodeficiency virus, type 1 (HIV-1). Sixty-five samples were proved positive by Western blot analysis. Among individual high risk groups, hemophiliacs had the highest positive rate of 20/60 (29.41%), followed by homosexual/bisexual males (41/1,264, 3.24%). The overall positive rate was 65/33,199 (0.19%). Ten cases were recognized as acquired immunodeficiency syndrome (AIDS), 1 case had AIDS-related complex (ARC) and 4 case had other apparently symptomatic infections. Among these 15 cases, 7 expired, 1 lost of follow-up and 7 surviving cases are being treated with zidovudine (AZT). Most of symptomatic HIV-1 antibody positive cases had abnormal T4/T8 ratio of 0.39 +/- 0.54 as compared with the asymptomatic HIV-1 carriers at a ratio of 0.81 +/- 0.69. The opportunistic infections included Pneumocystis carinii pneumonia (PCP) in 6 case, disseminated cytomegalovirus infection in 6 cases, herpes zoster virus infection in 3 case, candidiasis in 4 cases, syphilis in 3 cases, pulmonary tuberculosis in 2 cases, and others with cryptococcosis, salmonellosis, Mycobacterium avium-intracellulare infection, gonorrhea, Staphylococcus aureus endocarditis and bacterial sepsis, etc. The natural history of HIV-1 infection to AIDS involved acute and persistent multiple infections. Although prevalence of HIV-1 infection was low in Taiwan, nationwide surveillance of HIV-1 infection in various risk groups is still needed.

AIDS-Related Opportunistic Infections↗

PubMed1992

Four saponins from Oxytropis ochrocephala.

From Oxytropis ochrocephala Bunge, four saponins 1, 2, 3, and 4 were isolated. Saponins 1 and 2 are new compounds. The common genuine aglycone of the saponins is soyasapogenol B. The structures of those saponins were established by means of 13C-NMR, MS analyses, and chemical methods. In addition, a new interesting artifact aglycone 6 was obtained from the hydrolysate of these saponins and its structure was elucidated by spectral analyses and chemical transformations.

Carbohydrate Sequence↗

PubMed1992

Status and trend of HIV-1 infection and AIDS in Taiwan, December, 1991.

From May 1, 1985 to December 31, 1991, a total of 4,962,707 serum samples from 8 population groups in Taiwan were tested for anti-human immunodeficiency virus type 1 (anti-HIV-1). In total, 256 samples were seropositive; of these individuals, 43 developed acquired immunodeficiency syndrome (AIDS): 29 were homosexuals; 5 were hemophiliacs; 8 were heterosexuals and 1 was of unknown risk. Although the prevalence of HIV-1 infection and AIDS remains low compared with other countries, since 1988 the increase has been rapid. Before 1977 the majority were homosexuals and hemophiliacs; thereafter the risk groups diversified, with a trend away from homosexuals and hemophiliacs towards heterosexuals and intravenous drug abusers (IVDAs). A few patients have caused serious social problems for the public, health care workers and families. Active community efforts are needed to achieve future success in the control of HIV-1 infection and AIDS in Taiwan.

Acquired Immunodeficiency Syndrome↗

PubMed1992

Clinical evaluation of fleroxacin in the treatment of bone and joint infections.

The objective of this open label, non-comparative study was to evaluate the efficacy and safety of fleroxacin 400mg administered orally once daily to patients with acute osteomyelitis and/or acute septic arthritis. Nineteen patients (10 males and 9 females) were evaluable for the analysis of clinical efficacy and safety. Of these, 7 (36.8%) had osteomyelitis and 12 (63.2%) had septic arthritis. Bacteriological cures were reported in 6 of 7 patients (85.7%) with osteomyelitis and in 8 of 11 patients (72.7%) with septic arthritis. The median duration of treatment for the clinical cures in osteomyelitis and septic arthritis were 29.5 days and 46 days respectively. The eradication rate for the most common pathogens, Salmonella enteritidis and Staphylococcus aureus were 77.7% and 80.0%, respectively. The clinical response was cure in 4 of 7 patients (57.1%) evaluable for osteomyelitis, and in 9 of 12 patients (75.0%) evaluable for septic arthritis at the three-month follow-up after treatment. Adverse reactions were minimal. It is concluded that fleroxacin appears to be an effective and safe in the treatment of acute osteomyelitis and acute septic arthritis.

Acute Disease↗

PubMed1991

Endometriosis of the perineum; report of two new cases and a review of literature.

The incidence of endometriosis at the episiotomy site is quite rare. We have experienced two cases of perineal endometriosis over a 9 year period. The typical clinical history and local findings enable us to make the correct diagnosis of both cases. The treatment of choice is complete surgical excision of endometrial tissue and usually obtains permanent cure. A review of the English literature showed there were 66 cases reported previously. The possible pathogensis of endometriosis and various modality of treatment were also discussed.

Adult↗

PubMed1991

Three saponins from Oxytropis species.

Three flavonoids and three saponins have been isolated from Oxytropis species. Their structures were determined as isorhamnetin-3-O-beta-D-glucoside, rhamnetin-3-O-beta-D-galactoside, apigenin, 3-O-[alpha-L-rhamnopyranosyl (1----2)-beta-D-glucopyranosyl(1----4)-beta-D-glucuronopyranosyl]+ ++soyasapogenol B, 3-O-[beta-D-glucopyranosyl(1----2)-beta-D-glucuronopyranosyl] azukisapogenol and a new saponin 3-O-[beta-D-glucopyranosyl(1----2)-beta-D-glucopyranosyl]-25-O-alpha-L- rhamnopyranosyl-(20S,24S)-3 beta,16 beta, 20,24,25-pentahydroxy-9,19-cycloanostane.

Carbohydrate Sequence↗

PubMed1991

Isolated cryptococcosis of the adrenal gland.

A case of isolated adrenal cryptococcosis is reported. A patient with a history of diabetes mellitus had symptoms of left flank pain. Roentgenological and sonographic findings of the adrenal gland were indicative of a malignant tumour. Tissue obtained from surgery showed fungal granuloma and a poorly encapsulated cryptococcal organism was identified by special stains. A post-operative serum cryptococcal antigen test was positive, and the patient was successfully treated with surgery and a course of amphotericin B. After a 7-month follow-up period, there is no evidence of recurrence or dissemination.

Adrenal Gland Diseases↗