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Biomedical subjects

D C Wu

Publications and source records attributed to D C Wu.

At least 55 records · Page 3Linked to original sources
PubMed1991

Age-dependent variation of zinc-65 metabolism in LACA mice.

Mice were gavaged with zinc-65 solution, 8.6-19.3 kBq per mouse, and the whole-body retention and organ content of zinc-65 were measured at different times after administration. The age-dependence of the fractional absorption of zinc-65 from the gastrointestinal tract (f1), the endogenous faecal excretion fraction of zinc-65 (EFEF), tissue distribution and whole-body retention were determined. The f1 values obtained were 0.86 +/- 0.15, 0.64 +/- 0.11, 0.52 +/- 0.07 and 0.39 +/- 0.02 in suckling, adolescent, young adult and older mice, respectively. The EFEF values determined were 0.083 +/- 0.008, 0.099 +/- 0.004, 0.122 +/- 0.018 and 0.144 +/- 0.005 of intraperitoneally injected zinc-65 in suckling, adolescent, young adult and older mice at administration. Zinc-65 mainly distributed in the liver, muscle, lung, kidneys and bone. In some tissues, there was an inverse relationship between the relative content of gavaged zinc-65 and the animal's age at administration. The whole-body biological half-lives of zinc-65 increased with animal age. The influence of the age-dependent variation of zinc-65 metabolism on internal dose and on radiation protection is discussed.

Administration, Oral↗
PubMed1991

Radiation effects on the immunological functions and membranes of alveolar macrophages of rats.

Alveolar macrophages (AM) from BCG activated Wistar rat were irradiated with different doses of Gamma rays in vitro. The effects of radiation on their immunological functions and membrane damage were studied. The non-specific cytotoxicity and specific phagocytosis of AM irradiated with dose of 0, 100, 300 and 500 Gy decreased with the increase in dose. The relative fractions of Lactate Dehydrogenase and Beta-glucuronidase (beta-glu) activity in supernatant increased with the increase in dose. There was a correlation between the suppression of immunological functions and the degree of damage of cytoplasmic and lysosomal membranes of AM after irradiation. Na2SeO3, a protective agent of cell membranes, alleviated this effect on the suppressive cytotoxicity indices of irradiated AM.

Animals↗
PubMed1990

Central nervous system infection after endoscopic injection sclerotherapy.

Central nervous system (CNS) infection is a rare complication of endoscopic injection sclerotherapy (EIS) for esophageal varices. We report two patients, one of whom developed a solitary brain abscess, and the other, acute meningitis, after EIS. They presented with high fever initially, and then with changes in mental status. In the case of the solitary brain abscess, the CSF revealed evidence of infection, and CT scan disclosed a brain abscess in the left temporo-parieto-occipital region. This patient received EIS six times and developed the CNS complication 4 wk after the last EIS. There was no growth in either the CSF or the abscess cultures in this case. The other patient with acute meningitis, which developed on the second day after the second session of EIS, had a positive CSF culture of Klebsiella pneumoniae. Both of these patients died despite antibiotic treatment, and craniotomy with drainage in the patient with a brain abscess.

Acute Disease↗
PubMed1990

[Cytostatic and growth-stimulating effects of alveolar macrophages of rats on tumor cells].

Cytostatic and growth-stimulating effects of alveolar macrophages (AM) of rats on tumor cells were studied. The experimental results are summarized as follows. 1. The cytotoxicity of AM activated with BCG to tumor cells was increasing with the increase of effector cells/target cells (E/T) ratio. AM without the treatment with BCG expressed slight cytotoxicity to tumor cells at a high E/T, and growth-stimulating effect on tumor cells, at a low E/T. 2. AM after 24-hour culture had a lower manifestation of cytotoxicity to human lung adenocarcinoma cell line than that of AM without 24-hour culture, and had a growth-stimulating effect on B-16 cell line. 3. Cytostatic and growth-stimulating effects of AM without or with 24-hour culture were decreasing with the increase of irradiation doses.

Adenocarcinoma↗
PubMed1989

Effect of inhaled 239PuO2 on alveolar type II cells.

Morphological changes of rat alveolar type II (AT-II) cells were studied at 8 and 10 months following inhalation of 239PuO2 to elucidate the biological role of AT-II cells in the induction of lung tumours. TEM micrographs of random sections of lung were analysed qualitatively and quantitatively using an automatic image analyser. Eighteen morphometric parameters were obtained according to stereological principles. The results showed that, following the inhalation of 239PuO2, AT-II cells became less differentiated and the metabolism of the pulmonary surfactant in AT-II cells was disturbed.

Aerosols↗
PubMed1989

Ocular injuries from accidental laser exposure.

This report presents 29 cases of ocular injury (31 eyes) caused by accidental laser exposure. Twenty-eight eyes were injured during laser adjustment and alignment. Nineteen eyes were damaged by Q-switched lasers at a wavelength of 1064 nm. Macula damage occurred in 25 eyes. During the early phase after injury, there were different degrees of retinal coagulation, edema or hemorrhage in exposed spots and there occurred immediate reduction of visual acuity. Effusion of blood and exudate was absorbed in most injured eyes under treatment lasting several weeks; meanwhile, gray-white scars appeared. Macular holes appeared in seven cases a week after injury, thus extending the course of the injury. Nine cases (10 eyes) were followed-up for 4-10 y, during which time the condition of eight cases (nine eyes) remained stable. The causes of the laser accidents and the relationship between the damage effects and exposure doses were analyzed.

Accidents, Occupational↗
PubMed1989

Microdosimetry of rat alveolar type II cells irradiated with alpha particles from 239PuO2.

The alveolar type II cell is one of the critical cells for radiation damage in the lungs after inhalation of radioactive aerosols. With the aid of a Quantimet-970 image analyzer and a VAX-11/780 computer, we calculated the radiation dose to rat alveolar type II cells from alpha particles emitted by 239PuO2. A series of dosimetric parameters for type II cells, including track length distribution, linear energy transfer (LET), values of the specific energy for a single hit of a spherical target (z1), cellular dose, hit number, and their spatial distributions were calculated. By comparing the volume density of type II cells and lung tissue with energy deposited in alveolar type II cells, we found that the energy deposited per unit volume of type II cells was larger than that of lung tissue excluding type II cells. The z1 for spherical targets and the LET across type II cells were less than those in lung tissue excluding type II cells. The age of the rat and damage to lung by inhalation may significantly influence some of the parameters. The neoplastic transformation probability for type II cells is also discussed. The results suggest that the type II cell is an important target cell in the rat lung for exposure to inhaled 239PuO2.

Aerosols↗
PubMed1989

[Radiation effects on expression of FC-receptor of alveolar macrophages of rat and their specific phagocytosis].

BCG-activated alveolar macrophages (AM) of Wistar rats were irradiated with different doses of gamma-ray in vitro. The effects of radiation on the expression of their Fc-receptor and specific phagocytic activity were observed. AM, after irradiation with doses of 0, 100, 300 and 500 Gy, showed decreasing phagocytic activity to chicken red blood cells (CRBC) opsonized with anti-CRBC antibody with no change in phagocytic indices. The expression of Fc-receptor of AM was, however, increased.

Animals↗
PubMed1987

Optic disk cupping and pallor measurements of patients with a disk hemorrhage.

We evaluated whether the rate of occurrence of glaucomatous disk damage in eyes with an optic disk hemorrhage differed from the rate of occurrence in control eyes. We compared 24 patients with a disk hemorrhage to 24 control patients, who had been matched for diagnosis, disk appearance, and visual fields. Cup volume and cup-to-disk area ratio of the optic disk were measured using the stereophotogrammetric technique, and area of pallor was measured using computerized image analysis. We found that diabetes increased the probability that a patient would have a disk hemorrhage, and that a hemorrhage was associated with progression of glaucomatous disk changes in half of the cases during the mean 3.1-year follow-up period. However, the mean rate of glaucomatous disk damage in patients with a hemorrhage was not different from matched control patients. A disk hemorrhage is a sign of later disk damage, but it does not alter the rate of glaucomatous disk progression.

Eye Hemorrhage↗
PubMed1987

Increase of pallor and fluorescein-filling defects of the optic disc in the follow-up of ocular hypertensives measured by computerized image analysis.

In 24 ocular hypertensive patients, two optic disc fluorescein angiograms were obtained a mean of 3.9 years apart. Using computerized image analysis, we measured the area of pallor and the fluorescein-filling defect area within the disc and the fluorescein circulation parameters representing the filling rates of optic disc, choroid, and retinal vessels. The results indicated that increase in pallor and fluorescein-filling defect areas, as well as a slowed filling rate of the retinal veins, correlated with glaucomatous progression.

Aged↗
PubMed1984

Current surgical interests in China.

Until recently, China had been isolated from Western countries for almost 30 years. Surgeons of Western countries, perhaps, are interested to know what is happening in surgery in China. This communication reviews the current interests in Chinese surgery. It is by no means complete, nor is that the intention. The intention is to introduce to our foreign colleagues a general overview of some highlights in Chinese surgery.

Bone and Bones↗
PubMed1982

Anomalous chordae tendinae. A source of echocardiographic confusion.

A unique instance of an anomalous chorda tendinae visualized in the left ventricular outflow tract during M-Mode and two-dimensional echocardiography, and subsequently confirmed during surgery for concomitant severe rheumatic valvular disease, is described. The M-Mode appearance can be confused with more serious forms of heart disease manifesting extraneous echoes in the outflow tract, and an approach to these echoes is described, based on a review of the literature.

Adult↗
PubMed1981

Primary carcinoma of the lung.

118 patients with carcinoma of the lung seen in the Department of Cardiovascular and Thoracic Surgery, Tan Tock Seng Hospital, Singapore were followed for five years. The aim was to determine the survival of these patients in relation to the stage of the disease as well as the histologic type of carcinoma. 22 patients were in stage 1, 13 in Stage II and 83 in Stage III. Thoracotomy was performed in 62 patients and the rest had biopsy of distal lymph nodes. 43.3% of the carcinoma were squamous cell, 25% adenocarcinoma, 27% large cell, anaplastic, 2.9% oat cell and 1.8% bronchoalveolar cell carcinoma. Survival of the patients were found to be closely related to stage of the disease but not with the histologic type.

Adult↗
PubMed1981

Surgical management of rheumatic heart disease in Singapore.

Over the last three decades there has been a world-wide decline in the incidence and severity of rheumatic fever and rheumatic heart disease, but the death rate in Singapore from chronic rheumatic heart disease has risen from 3.6 per 100,000 population in 1966 to 4.4 per 100,000 in 1977. Valvular lesions from rheumatic heart disease are very common, and between 1967 to 1979, 715 surgical procedures were performed for rheumatic valvular disease, and of these, 654 procedures involved the mitral valve which was most commonly affected by the disease process. Since many of the patients were female and in the child-bearing age, conservative procedures on the mitral valve were performed whenever possible. Mitral valvotomy for mitral stenosis relieved symptoms effectively; and for restenosis of the mitral valve, more than half of the patients underwent a second valvotomy with functional improvement. Mitral valve replacement was reserved for the severely distorted valve, sometimes calcified, and where there was stenosis associated with incompetence. Between 1971 to 1979, 162 mitral valves were replaced and actuarial studies showed 80% survival five years after surgery. 30 aortic and mitral valve replacements were performed in this same period with an operative mortality of 16.7%. Only 75 aortic valves were replaced for rheumatic valvular disease and 14 of these also had associated mitral and triscuspid valve disease. The prosthetic valves commonly used for replacement were the Starr-Edwards non-cloth covered valves, models 6120 and 1260. All patients that had valve replacements were treated with long-term anticoagulation with Warfarin. The incidence of thromboembolism was low, being 8% for mitral valve replacement and the majority of these episodes occurred in the first three months after surgery.

Adolescent↗