Biomedical subjects

W F Cheng

Publications and source records attributed to W F Cheng.

16 recordsLinked to original sources

PubMed1992

[Efficacy of ivermectin for control of microfilaremia recurring after treatment with diethylcarbamazine. I. Clinical and parasitological observations].

We compared the efficacy of a single dose of ivermectin with that of a standard course of deithylcarbamazine (DEC) for the control of microfilaremia in 60 patients with banrroftian filariasis who had developed recurrent microfilaremia after each of three or more prior treatments with DEC. The study was done as a randomized, double-blind trial. Complete, but transient clearance of microfilaremia was observed in both treatment groups. One year later, recurrent microfilaremia was present in 7 patients treated with ivermectin and in 5 treated with DEC. Pretreatment levels of microfilaremia were significantly higher in patients who relapsed within one year after treatment than in those who remained amicrofilaremia. Side effects of either treatment were common but mild. Febrile reactions were more frequent in the ivermectin group: while localized reactions consistent with a flare up of acute filarial disease occurred mostly in the DEC group. We conclude that ivermectin is an effective and practical alternative to DEC for treatment of recurrent microfilaremia due to bancroftian filariasis.

Adolescent↗

PubMed1991

An approach to establishing N-nitroso compounds as the cause of gastric cancer.

Although gastric cancer is the most common cause of mortality from cancer, its etiology is not yet clear. To elucidate the role of N-nitroso compounds, we investigated 30 cases of gastric cancer by determination of the contents of nitrate and ascorbic acid and by detection of mutagens in urine. Cases were paired 1:1 with patients with dysplasia and normal controls of the same sex and age group. In comparison with normal controls, the gastric cancer group had higher nitrate and lower ascorbic acid levels in urine. Mutagenicity was observed in the urines of 83.3% of the gastric cancer cases and in 16.6% of the dysplasia group, but in none of those from normal controls. When the N-nitroso compound content of gastric juice was determined, the levels in control subjects were significantly lower than those in persons with gastric cancer. These results support the hypothesis that the cause of gastric cancer may be N-nitroso compounds.

Ascorbic Acid↗

PubMed1991

Efficacy of ivermectin for control of microfilaremia recurring after treatment with diethylcarbamazine. I. Clinical and parasitologic observations.

We compared the efficacy of a single dose of ivermectin with that of a standard course of diethylcarbamazine (DEC) for the control of microfilaremia in 60 patients with bancroftian filariasis who had developed recurrent microfilaremia after each of three or more prior treatments with DEC. The study was done as a randomized, double-blind trial. Complete, but in some cases, transient clearance of microfilaremia was observed in both treatment groups. At one year, recurrent microfilaremia was present in seven patients treated with ivermectin and in five treated with DEC. Pretreatment levels of microfilaremia were significantly higher in patients who relapsed within one year after treatment than in those who remained amicrofilaremic. Side effects with both treatments were common, but mild. Febrile reactions were more frequent in the ivermectin group; localized reactions consistent with a flare-up of acute filarial disease occurred mostly in the DEC group. We conclude that ivermectin is an effective and practical alternative to DEC for treatment of recurrent microfilaremia due to bancroftian filariasis.

Adolescent↗

PubMed1991

Efficacy of ivermectin for control of microfilaremia recurring after treatment with diethylcarbamazine. II. Immunologic changes following treatment.

We compared the effect of a single dose of ivermectin with that of a standard course of diethylcarbamazine (DEC) on several parameters of the host's antifilarial immune response in 60 patients with bancroftian filariasis enrolled in a double-blind drug trial. All participants had measurable serum levels of antifilarial antibodies and parasite antigens at the onset of the study. Drug-induced clearance of microfilaremia was associated with a temporary increase in HC 11 antigenemia and a decrease in serum levels of antibodies to soluble filarial antigens. Antigenemia progressively declined in patients who remained amicrofilaremic after treatment, but declined and then increased in persons with recurrent microfilaremia. Treatment triggered a sustained increase in serum levels of interleukin-1, tumor necrosis factor, and interleukin-6 in all patients studied. Although ivermectin and DEC are believed to exert their antiparasite activity via different mechanisms, the same pattern of serologic changes was observed in patients treated with either drug.

Adolescent↗

PubMed1991

Monitoring of filarial antigens in jirds and patients after treatment.

We developed a sandwich ELISA with monoclonal antibodies to monitor filarial antigens in animals and patients after infection and treatment. Levels of antimicrofilarial antibodies and parasite antigens were measured periodically in 40 B. malayi infected jirds. In all animals L3 HC11 antigen was detected earlier than Mf ES34 antigen, while antimicrofilarial antibodies appeared much more slowly. These serologic changes precede the onset of patent infections. After 3 courses of treatment with DEC and M170, the levels of parasite antigen in sera and of Mf in peritoneal cavities were monitored in 23 infected jirds. In 8 jirds Mf became negative, no adult worms were found in 7 jirds and a single degenerating female worm was present in 1 jird. ES34 and HC11 were undetectable in 8/8 and 6/8 necropsy sera. Mf persisted in 11 animals, 9 jirds were necropsied, 8 contained adult worms. Detectable levels of ES34 or HC11 antigen were present in 7/9 and 8/9 from these animals. In sham-treatment, few changes were noted in control animals. Thus, parasitological findings at necropsy are correlated with the results of antigen detection assay. We analyzed serial serum samples from 32 bancroftian microfilaremia collected 1-42 months after DEC therapy. Mf resolved rapidly in all treated individuals. ES34 disappeared faster than HC11, 3 months after treatment. Levels of ES34 and HC11 antigens remained detectable or rising after treatment in 8 and 10 individuals. Four patients' Mf recurred 20-42 months after treatment. These findings show that the remaining or a rise in serum levels of antigen after therapy predicts recurrent microfilaremia in patients and additional treatment is needed.

Animals↗

PubMed1990

Malignant mesothelioma with bone metastases.

Malignant mesothelioma has rarely been reported to metastasize to bone. This is a report of a 71-year-old man who presented with pleural mesothelioma. After a course of chemotherapy, the patient developed lower back pain. Plain X-ray and bone scan were negative for metastases, but magnetic resonance imaging (MRI) revealed multiple metastatic lesions to the thoracolumbar vertebrae. Subsequent lumbar spine biopsy confirmed the presence of malignant mesothelioma. The patient then received radiation therapy. This report illustrates an unusual presentation for malignant mesothelioma and shows that, in addition, when bone metastases are clinically suspected, MRI may be a useful adjunct to more conventional imaging approach.

Aged↗

PubMed1990

Comparison of Dot-ELISA with Sandwich ELISA in detecting circulating antigen in patients with bancroftian filariasis.

Dot-ELISA assay was compared with standard Sandwich ELISA in detecting parasite antigen in sera from patients with bancroftian filariasis. The same monoclonal antibody and the same serum samples were used in both assays. With Dot-ELISA, 67 of 70 serum samples from microfilaremic patients were positive at a dilution of 1:50. End titers ranged from 1:80 to 1:1 280. While with Sandwich ELISA, 64 of the 70 serum samples were positive at a dilution of 1:10. End titers ranged from 1:10 to 1:320. The specificity of both assays was over 91%, but their sensitivity was markedly different. Dot-ELISA could detect as little as 0.055 ng/ml microfilarial antigen added to normal human serum, whereas the lower limit of detection by Sandwich-ELISA was 10 ng/ml parasite antigen. An additional advantage of Dot-ELISA is that it does not require radioactivity or sophisticated equipment and, therefore, can be performed in virtually all filariasis-endemic areas.

Animals↗

PubMed1990

Comparison of Dot-ELISA with Sandwich-ELISA for the detection of circulating antigens in patients with bancroftian filariasis.

We compared the performance of a newly developed Dot-ELISA with that of a previously described Sandwich-ELISA to detect parasite antigens in sera from patients with bancroftian filariasis. The same monoclonal antibody and the same sera were used in both tests. In the Dot-ELISA, 67 of 70 sera from microfilaremic donors were deemed to contain filarial antigens when screened at a dilution of 1:50. End titers were 1:80-1:1280. With the Sandwich-ELISA, 64 of the same sera were positive at a dilution of 1:10 and 42 were positive at a dilution of 1:50. End titers were 1:10-1:320. The specificity of both assays was greater than 95%, but their sensitivity was remarkably different. The Dot-ELISA could detect as little as 0.055 ng/ml microfilarial antigen added to normal human sera, whereas the lower limit with the Sandwich-ELISA was 10 ng/ml parasite antigen. Additionally, the Dot-ELISA does not require radioactivity or sophisticated equipment and, therefore, can be performed in virtually all filariasis-endemic areas.

Animals↗

PubMed1990

Parasite antigenemia in untreated and treated lymphatic filarial infections.

To evaluate the merit of antigen detection assays as a tool to monitor the efficacy of chemotherapy for lymphatic filariasis, we serially measured antigen levels in sera from jirds infected with Brugia malayi and from humans with bancroftian filariasis. Antigenemia was detected in all animals with parasitologically proven infection and was present in jirds with prepatent or occult filariasis. Antigen levels correlated with worm burdens, and progressively declined in drug-cured animals. Treatment with diethylcarbamazine (DEC) triggered a transient increase in serum levels of filarial antigens bearing the epitope recognized by the monoclonal antibody HC 11. All patients with bancroftian filariasis became amicrofilaremic within one week after DEC treatment. Antigenemia levels slowly declined over a period of several months in all but one treated individual. Forty-two months after treatment, progressively rising antigen levels are present in 10 patients. Six of these remain amicrofilaremic; in the other 4, elevated antigenemia levels preceded or were detected at the same time as recurrent parasitemia. Periodic monitoring of antigenemia levels after treatment of patients with lymphatic filariasis can be used to identify individuals who are likely to develop recurrent microfilaremia before the parasites become detectable in blood samples, thereby allowing timely retreatment.

Animals↗

PubMed1987

[Pattern recognition on the trace element spectrum in gastric cancer and peptic ulcer].

The trace element spectrum of gastric tissue and whole blood specimens from gastric cancer and peptic ulcer patients was recognized with pattern recognition technique in order to obtain the chemical information of gastric cancer. Thirty specimens were obtained from cancer patients in each of the 58 gastric tissues and 54 whole blood specimens. Five pathological types were divided into two groups: peptic ulcer and dysplasia as the ulcer group; well-differentiated, undifferentiated and mucinous carcinoma as the cancer group. The accuracy of recognizing the several spectra was 90%: nine trace element spectra (Cu, Zn, Ni, Co, Cr, Cd, Mn, Fe and Mg) for the tissue specimens from the cancer and ulcer groups; six (Cu, Zn, Mn, Co, Cr and Cd) for dysplasia and well-differentiated adenocarcinoma tissues; five (Cu, Ni, Cr, Cd and Fe) for the whole blood specimens from these two groups and six (Cu, Zn, Cr, Cd, Fe and Ni) for the whole blood specimens from dysplasia and peptic ulcer (including 10 normal individuals). The data were treated by non-linear mapping method and calculated by TRS-80 III type microcomputer.

Adenocarcinoma↗

PubMed1985