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Biomedical subjects

C C Wong

Publications and source records attributed to C C Wong.

At least 55 records · Page 3Linked to original sources
PubMed1989

Biochemical and cellular changes in bronchoalveolar lavaged samples from rats after inhalation of mosquito-coil smoke.

A group of 30 female albino rats were exposed to mosquito-coil smoke, 8 hours a day, 6 days per week, for 6 months. Another group which was exposed to air served as control. At the end of the experiment, the enzyme activities, total protein and lecithin contents as well as cellular responses in the lung lavage between the control and smoke-exposed rats were compared. Morphological observations using scanning and transmission electron microscopy demonstrated that the alveolar macrophages of smoke-exposed rats lost their typical ruffled membranes. They possessed small cytoplasmic processes on their smooth cell surfaces, small particles in phagolysosomes and mitochondria with a very electron-dense matrix. The levels of total protein and lecithin and the activities of lactate dehydrogenase, acid phosphatase and beta-glucuronidase in the lung-lavage fluid of smoke-exposed rats were significantly (P less than 0.05) higher than those of the controls. Increases (P less than 0.05) of serum enzymes, including lactate dehydrogenase, aspartate aminotransferase, isocitrate dehydrogenase and aldolase, indicated damage of liver tissues, but the levels of serum urea and urea nitrogen remained at the control levels implying normal functions of the kidneys of the mosquito-coil smoke-exposed rats. The level of serum tri-iodothyronine also increased significantly (P less than 0.05), but thyroxine remained at the control level.

Animals↗
PubMed1989

Immunomodulatory effect of methimazole on inbred mice.

The effects of antithyroid drug, methimazole (MMI, 1-methyl-2-mercaptoimidazole), on the immune system of inbred mice, C57BL/6, were studied. The proliferative response of splenic lymphocytes to concanavalin A (Con A) and allogeneic stimulator cells was reduced when the mice were provided with 0.1% MMI in tap water ad libitum for two to four weeks. The reduction of proliferative response was correlated with a lower frequency of proliferative spleen cells in the MMI-treated mice. The ability to produce macrophage activating factor of these spleen cells and the levels of hemolytic plaque-forming cells were also reduced. However, the mitogenic response of the splenic lymphocytes to lipopolysaccharide (LPS) was enhanced. In order to investigate whether the impaired cell-mediated and humoral immune systems would increase the susceptibility of the MMI-treated animal to the growth of tumor cells, mice were challenged with a lethal dose of Moloney virus-induced T cell lymphoma of C57BL/6 mice (MBL-2). The time required for 50% of the animals to die was reduced from 15 days for the normal mice to 10 days for the MMI-treated mice.

Adjuvants, Immunologic↗
PubMed1988

Effect of neonatal monosodium-L-glutamate treatment on the response of isolated uterine preparation to various uterine contraction stimulators.

1. The uterine activity of rats treated neonatally with MSG was examined in vitro by measuring the contractile response of the tissue to hormone/chemical stimulation. 2. The uterine responses to ACh and ANG II remained unchanged following neonatal MSG treatment while those to PGF2 alpha were sensitized. 3. The responses to OT and 5-HT were characterized by a reduction of the maximal contractile force and the rate of change in tension increased and decreased compared with the control with OT and 5-HT respectively. 4. Data suggested that these changes on uterine contractility could be ascribed to various possible mechanisms of action of MSG.

Acetylcholine↗
PubMed1988

Neonatal monosodium-L-glutamate treatment reduced lipolytic response of rat epididymal adipose tissue.

1. The effect of neonatal monosodium-L-glutamate (MSG) treatment on lipolysis in rat epididymal adipose tissue was studied. A reduction in the basal lipolysis was observed in the MSG-treated rats. 2. This was accompanied by a decrease lipolytic response to isoprenaline, adrenocorticotropic hormone, forskolin, isobutylmethylxanthine and dibutyryl-cAMP. 3. The addition of adenosine deaminase, which inactivates endogenous adenosine in the medium, did not normalize the basal and the hormone stimulated lipolytic responses. 4. The maximal lipolysis stimulated by adenosine deaminase or 8-(p-sulfophenyl)-theophylline (8-SPT), an adenosine antagonist, was significantly lower in the MSG-treated rats. 5. Moreover, there was no change in the sensitivity of adenosine receptors to its antagonist as reflected by the similar potency of 8-SPT in eliciting the lipolytic response in both the control and MSG-treated rats. 6. In conclusion, neonatal MSG treatment in rats induced a general reduction of lipolytic response in the epididymal adipocytes which cannot be explained by an enhancement of the adenosine inhibitory system.

Adenosine Deaminase↗
PubMed1988

Surgical treatment of primary tumours of the innominate bone.

9 cases of primary malignant tumours of the pelvis were treated in our department from 1981 to 1987. There was three chondro-sarcomas, one giant cell tumour and five had soft tissue tumours. One has a classical hemipelvectomy while eight had limb preservation surgery performed. In this later group., three had type I (Enneking) resection, three combined type II/III and one a type III resection. Four patients have died since and three deaths were related to surgery and its complications. As to date, no local recurrences has occurred in those living (up to 7 years' follow up). We feel that local resection with limb preservation provides adequate local control of tumour. Various reconstructive procedures to cover skin defects, and reconstruct stability of the pelvis or create hip stability were also performed. Patients with no previous irradiation has less mobidity and tend to do well.

Adolescent↗
PubMed1987

Putative thyroid hormone receptors in red blood cells of some reptiles.

Putative triiodothyronine (T3) receptors have been detected in the nuclei of red blood cells (RBC) in a number of reptile species. The binding characteristics of T3 receptors in vitro were dissociation constant (Kd) 9.1 to 28.58, 36.8 and 40, and 11.12 and 11.36 pM, and binding capacity (Bmax) 0.12 to 0.37, 0.17 and 0.24, and 0.19 and 0.28 fmol per million cells in the rat snake (Ptyas korros), soft-shelled turtle (Trionyx sinensis), and tokay gecko (Gekko gecko), respectively. These data were obtained in all species using in vitro incubation of whole cell according to current receptor studies on living cells. With modified technique in subsequent experiments, these values of the binding characteristics were seemingly low. The discrepancy was ascribed to the assessment of "free" fraction of hormone which would be used in subsequent calculation.

Animals↗
PubMed1987

Management of colorectal adenoma: a Singapore experience.

The racial distribution and pathology of 115 colorectal polyps from 72 patients were analysed. There were 88 (77%) adenomas. 90.9% of these were from Chinese and none from Malay patients. 79% were found in the sigmoid colon and rectum. The racial and site distributions of adenomas reflect the patterns of carcinoma seen in Singapore. The management of adenoma was discussed. Annual surveillance for high-risk and three yearly surveillance of low-risk patients up to an arbitrary age of 75 years is recommended.

Adenoma↗
PubMed1984

Pathologic hip fractures secondary to amyloidoma. Case report and review of the literature.

Amyloidoma primarily involving bone and lymph node is described in a 60-year-old male patient. The patient had pathologic fractures of both hips through a deposit of amyloid in the neck of the femur. The prolonged insidious course of the disease was uncomplicated by hypercalcemia, hematologic abnormalities, or renal failure so characteristic of untreated myeloma. The bone marrow contained less than 10 percent plasma cells in different stages of maturity. Radionuclide bone scanning demonstrated other osseous amyloid lesions that were not detected by routine radiologic examination. This is the first reported case of pathologic fractures of both hips secondary to amyloidoma.

Amyloidosis↗
PubMed1983

Influence of age, strain and season on circadian periodicity of pituitary, gonadal and adrenal hormones in the serum of male laboratory rats.

The influence of age, strain and season on the circadian pattern of serum levels of LH, FSH, prolactin androgens and corticosterone was studied in five groups of male laboratory rats. Significant 24-hour periodicity was observed for serum levels of corticosterone in all five groups, for androgen levels in four, for prolactin levels in three, for LH levels in two and for FSH levels in one group of rats. There were significant influences of age, strain and season on the temporal patterns and/or on 24-hour mean serum hormone levels. The results indicate that some of the disagreements on existence or nonexistence of circadian rhythms and on rhythm patterns in serum hormone levels may be explained by the fact that animals of different ages or strains had been used or that experiments were performed at different times of the year.

Adrenal Cortex Hormones↗
PubMed1983

Influence of age, strain and season on diurnal periodicity of thyroid stimulating hormone, thyroxine, triiodothyronine and parathyroid hormone in the serum of male laboratory rats.

The influence of age, strain and season on the diurnal pattern of serum hormone levels from the pituitary-thyro-parathyroid complex was studied in male laboratory rats. Distinct 24 h periodicity in the serum levels of thyroid stimulating hormone (TSH) and triiodothyronine (T3) was observed in all groups of rats. There was no influence of age (40, 60 and 90 days old Sprague-Dawley rats), but a significant influence of strain (Sprague-Dawley vs. BH/Ztm rats) and season (summer vs. winter) on the diurnal pattern of serum TSH and T3 levels. Significant 24 h periodicity in serum thyroxine (T4) levels existed during winter in BH/Ztm rats, but not in Sprague-Dawley (SD) rats of any age. Adult SD rats demonstrated 24 h periodicity in serum levels of T4 only in summer. No diurnal periodicity in serum levels of parathyroid hormone (PTH) was observed in any group of rats. There were significant changes in 24 h mean serum levels of TSH and T3 throughout pubertal development. Twenty-four h mean serum levels of T3 and T4 were significantly higher in summer than in winter. Twenty-four h mean serum levels of T4 were significantly lower in BH/Ztm rats than in SD rats. Significant correlation was observed between serum concentrations of T3 and T4, TSH and T4, and between TSH and T3 in some groups of rats, but not in all. The results indicate that 24 h periodicity of serum hormone levels from the pituitary-thyroid complex of male laboratory rats may vary with age and strain of the animals and with the season of experiment performance.

Age Factors↗
PubMed1983

Circannual variations in serum concentrations of pituitary, thyroid, parathyroid, gonadal and adrenal hormones in male laboratory rats.

Seasonal effects were studied on basal levels of hormones in the serum of adult male Sprague-Dawley rats, which were born and raised under rigorously controlled laboratory conditions. Groups of 90-day-old rats were killed at monthly intervals by rapid decapitation. Significant fluctuations were observed throughout the observation period of 19 months in serum levels of TSH, prolactin, androgens, tri-iodothyronine and LH. Minor fluctuations were observed in serum levels of FSH, corticosterone, parathyroid hormone and thyroxine. The results indicate that male laboratory rats exhibit circannual and semi-annual fluctuations in serum levels of several hormones even though the animals were born, raised and maintained in constant laboratory conditions.

Androgens↗
PubMed1980

Transcutaneous electrostimulation in the management of postoperative pain: initial report.

A study was undertaken to investigate recent reports concerning the use of transcutaneous electrostimulation (TES) for relief of postoperative pain. Thirty patients undergoing elective herniorrhaphy were subjected to a standard perianaesthetic protocol. The patients were divided into three groups of ten, designated control, sham TES and TES. Postoperative analgesic requirements for each group were compared. The number of intravenous doses of meperidine given to each group in the first three hours after operation was control group 46 doses; sham TES group 38 doses; TES group 10 doses (p less than 0.0005). The number of intramuscular doses of meperidine in the 3-24-hour period was control group 21 doses; sham TES 22 doses; TES group 17 doses (no statistical difference between groups). A subjectively beneficial effect of TES was also established. Despite a number of difficulties encountered during this study, primarily concerned with the subjective nature of pain and its assessment, a useful trend which warrants further investigation has been established in the use of transcutaneous electrostimulation (TES) for postoperative analgesia.

Adult↗
PubMed1980

Effects of tri-iodothyronine, thyroxine and isopropyl-di-iodothyronine on thyroid-stimulating hormone in serum and pituitary gland and on pituitary concentrations of prolactin, growth hormone, luteinizing hormone and follicle-stimulating hormone in hypothyroid rats.

Replacement of the 3'-halogen of the tri-iodothyronine (T3) molecule by a propyl-group produces a thyromimetic analogue, 3'-isopropyl-3,5-di-iodo-L-thyronine (T2iPr), with high biological potency. A serum thyroid-stimulating hormone (TSH) suppression test with one single intraperitoneal injection of 3 or 30 nM-T3 or T2iPr or with 30 or 300 nM-thyroxine (T4) per kg body weight was performed on 56 adult male Lewis rats which were maintained for 3 weeks on an iodine-deficient diet containing 0.2% 6n-propyl-2-thiouracil (PTU). Blood was withdrawn from each rat by cardiac puncture 24 h before and 3, 7, 24 and 48 h after application of the iodothyronines. Raised serum levels of TSH, due to the treatment with PTU, were significantly reduced within 3 h of treatment with 30 nM-T3, 300 nM-T4, 3 or 30 nM-T2iPr and they remained low throughout the observation period. Treatment with 3 nM-T3, or 30 nM-T4 per kg body weight was less effective. Pituitary concentrations of growth hormone, TSH, prolactin and FSH were significantly reduced by the treatment with PTU. There was also a slight, but insignificant reduction of pituitary concentrations of LH. Treatment with T3, T4 or T2iPr stimulated the reaccumulation of growth hormone, TSH, prolactin, LH and FSH in the pituitary gland.

Animals↗
PubMed1979

Myocardial infarct imaging after cardiac surgery.

One hundred and nineteen patients undergoing cardiac surgery had postoperative myocardial imaging performed with technetium pyrophosphate in order to assess the incidence of perioperative myocardial infarction. Fifty-six patients had only coronary artery bypass graft (CABG) surgery, of whom 13(23%) had a positive scintigram. Thirteen patients had CABG with other cardiac surgery and six (46%) had a positive scintigram. Fifty patients had other cardiac surgery but no CABG, and of these eight (16%) had a positive scintigram. The overall incidence of positive scintigrams was 23%, whereas definite or probable ECG diagnosis of infarction was present in 14 patients (12%). Serum levels of cardiac enzymes were higher in patients with positive scintigrams, but this finding did not consistently reach statistical significance. The use of a left ventricular vent during surgery did not correlate with a positive scintigram, nor did the total time on cardiopulmonary bypass or aortic cross-clamping. Patients having cardiac surgery, including CABG and valve replacement, have a 23% overall incidence of positive scintigrams. This suggests that the incidence of infarction after cardiac surgery is higher than can be recognized from the conventional criteria of ECG and enzyme changes.

Cardiac Surgical Procedures↗
PubMed1977

Imaging of acute myocardial infarction using technetium 99m labelled phosphate compounds.

Technetium 99m pyrophosphate or polyphosphate administered intravenously soon after acute myocardial infarction produces positive images of the area and extent of myocardial necrosis. Forty-four patients have been studied of whom 39 had myocardial infarction. There was good correlation of the site and extent of infarction as indicated by the scintigram with electrocardiogram and cardiac enzyme criteria.

Acute Disease↗