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Biomedical subjects

C L Ho

Publications and source records attributed to C L Ho.

101 records · Page 6Linked to original sources

Renaturation of a reduced Taiwan cobra cardiotoxin.

Refolding of a denatured protein obtained by reducing cardiotoxin from the Taiwan cobra with mercaptoethanol has been carried out in aqueous and non-aqueous solutions. Oxidation of the reduced protein in 0.05 M phosphate buffer (pH 7.2) resulted in isolating an active protein which showed, as compared to native cardiotoxin, identical conformation and biological activities such as lethality, antigenicity and muscle contracture inducing activity. On the other hand, the reduced protein was undergoing incorrect SS-pairing and several inactive products were formed in a mixture of 1,2-ethanediol and 1-propanol (1 : 1; v/v).

Animals↗

Rapid determination of alkaline phosphatase reactivation.

A study was conducted to determine the feasibility of using the qualitative screening method specifying phenolphthalein monophosphate for differentiating reactivated and residual alkaline phosphatase activity. The relative increase in activity of the enzyme in the presence of MgCl2 serves to distinguish reactivated and residual alkaline phosphatase activity. Ten samples each of pasteurized (172 degrees F for 24 sec), sterilized (about 300 degrees F for a minimum of 2 sec) half-and-half and heavy cream were analyzed. Most samples yielded negative results initially but demonstrated activity after incubation 1 hr at 34 degrees C. The average values in terms of + marks, for the half and half and heavy cream in samples without MgCl2 were less than 1 and 2.4, respectively; for samples treated with MgCl2, the values were 2.18 and 4.6, respectively, indicating reactivated phosphatase activity. In samples containing various levels of raw milk, the activity observed in the diluted, Mg2+-containing samples was less than in the undiluted samples containing no Mg, indicating residual phosphatase activity.

Alkaline Phosphatase↗

T3 toxicosis and its relation to the iodide status in Singapore.

Baseline thyroid function tests (including total serum thyroxine iodide-T4I, total serum tri-iodothyronine T3 as well as T3 Sephadex Uptake Studies (T3U)) were determined in 82 normal Asian subjects. In addition, another group of normal volunteers (39) were assessed as regard serum and 24-hour urinary iodide levels to gauge the iodide status of the community; the results were comparable to that of goitre-free regions of the world. Having established the range of values of normal thyroid function tests, 103 consecutive clinically thyrotoxic patients (both new and relapsed cases) were similarly studied in an attempt to elucidate the magnitude of the problem of T3 toxicosis, and its relation to the iodide status in Singapore. Only three clinically hyperthyroid patients were foudn to have normal PBI T3 levels. A detailed analysis and discussion of the data is presented. It is concluded that T3 toxicosis is a rarity in Singapore.

Adult↗

Acute angle-closure glaucoma resulting from spontaneous hemorrhagic retinal detachment in age-related macular degeneration: case reports and literature review.

PURPOSE: Acute angle-closure glaucoma resulting from massive subretinal hemorrhage is a rare and catastrophic complication in age-related macular degeneration. Anticoagulant usage had been strongly correlated with this complication in previously reported cases. METHODS: Four patients (4 eyes), 3 men and 1 woman, developed angle-closure glaucoma with diffuse subretinal hemorrhage and total hemorrhagic retinal detachment. RESULTS: Serial funduscopic examinations and echographic studies in 2 eyes showed that the blood gradually accumulated in the subretinal space. It took more than 10 days for the bleeding to build up to bullous hemorrhagic retinal detachment and secondary glaucoma. Anti-glaucomatous agents were given and sclerotomy was performed in 3 of the 4 patients. Phthisical changes were observed subsequently in these 3 eyes. The eye that received early drainage of blood was an exception, and a small degree of residual acuity was retained. Three of the 4 patients had diabetes mellitus, and hypertension and vascular diseases were also present in the same 3 patients. CONCLUSIONS: Diabetes mellitus might be a predisposing factor for the impaired hemostasis. Anti-glaucomatous agents were of no effect in the management of intraocular pressure. Sclerotomy and drainage of blood help control intraocular pressure and relieve ocular pain. Poor final visual acuity is inevitable. However, phthisical changes might be prevented with early sclerotomy and drainage of blood.

Acute Disease↗

Epstein-Barr virus early ribonucleic acids as a diagnostic adjunct for relapsed metastatic tumors in patients with cured primary undifferentiated nasopharyngeal carcinoma.

PURPOSE: Epstein-Barr virus (EBV) has been consistently shown to be associated with undifferentiated nasopharyngeal carcinoma (NPC). In this article, the authors attempt to detect Epstein-Barr virus in distant relapsed metastatic sites in undifferentiated NPC patients with cured primary cancer. MATERIALS AND METHODS: In situ hybridization (ISH) technique is a reliable method to detect EBV early RNAs (EBERs) within NPC cells. We used a nonisotopical ISH technique to examine the presence of EBERs in paraffin-embedded tissues obtained from 1 paired specimen of primary NPC and its metastatic counterpart at liver and 2 metastatic specimens of retroperitoneal lymph nodes and bone. RESULTS: All the primary lesions and the metastatic tumors of NPC with undifferentiated histology contained EBERs that could be clearly detected in the nuclei of cancer cells. CONCLUSIONS: This article shows that EBERs can be successfully detected in cells of the distant relapsed metastatic sites. These results suggest that this nonisotopical ISH method of EBERs can be potentially used to diagnose NPC patients developing distant relapsed metastatic lesions with cured primary cancer early. It can offer quick information as to institute suitable salvage chemotherapy for these patients.

Adult↗

Ultrastructure of the skeletal muscles in acromegaly--before and after hypophysectomy.

Electron microscopic examination of the skeletal muscles in a patient with acromegaly and marked elevation of the serum growth hormone reveals altered mitochondria (pleomorphism, elongation, matrical pallor, and cristae abnormalities), glycogen granules infiltration, inclusion bodies, and vesicular dilatations. Nine months after surgical removal of the pituitary tumor, the serum growth hormone levels were markedly diminished. A repeat examination of the skeletal muscle shows that the previous ultrastructural changes in the muscles are related to the growth hormone levels.

Acromegaly↗

FDG-PET evaluation of indeterminate pancreatic masses.

PURPOSE: The purpose of this study was to assess the ability of PET with 2-[18F]fluoro-2-deoxy-D-glucose (FDG) to differentiate benign from malignant pancreatic masses in patients with indeterminate findings on CT. METHOD: We performed FDG-PET on 12 patients with indeterminate mass lesions and 2 patients with CT findings typical for malignancy. Eight were found to have pancreatic carcinoma and six had benign lesions. The final diagnosis was histopathologically confirmed in all patients but two with a presumed diagnosis of focal pancreatitis based on stable clinical follow-up for at least 12 months. Lesion uptake of FDG was evaluated qualitatively and semiquantitatively by determination of the standardized uptake value (SUV) RESULTS: With use of a 2.5 cutoff value for SUV, all eight malignant and four of six benign lesions were correctly categorized. Qualitative evaluation gave the same results. The two false-positive lesions had elevated SUV values of 3.4 and 3.8, respectively. CONCLUSION: Our results indicate that FDG-PET has potential value for assessing patients with CT findings that are indeterminate for pancreatic carcinoma. FDG-PET may obviate invasive diagnostic procedures in many patients with benign disease.

Adult↗

Expression of nm23-H1 in transitional cell carcinoma of the upper urinary tract.

Transitional cell carcinoma of the upper urinary tract is an uncommon neoplasm. Relatively little information is available regarding the clinical relevance of molecular markers. This study was performed to examine the importance of nm23-H1 gene expression (NM23-H1) in this type of tumors. Immunohistochemical expression of NM23-H1 was analyzed in 90 cases of upper urinary tract cancer, and was compared for its prognostic significance with conventional biological indicators. High expression of NM23-H1 was found in 7 cases (8%), intermediate expression in 32 cases (36%), and low expression in 51 cases (57%). Reduced NM23-H1 (defined as intermediate or low level of expression) was associated with a higher histological grading (p=0.002), invasive tumor growth (p=0. 002), or an increased proliferating cell nuclear antigen labeling index (p=0.004). NM23-H1 tended to inversely relate to later recurrence or long-term survival (p=0.06), but, only tumor staging was found to be significant in predicting clinical outcome (p=0.002). nm23-H1 appears to function as a tumor suppressor for upper urinary tract cancer, however, evaluation of NM23-H1 provides limited prognostic information.

Adult↗