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Biomedical subjects

C T Tan

Publications and source records attributed to C T Tan.

At least 145 records · Page 8Linked to original sources
PubMed1980

alpha-fetoprotein binding specificity for arachidonate, bilirubin, docosahexaenoate, and palmitate. A spin label study.

A dianionic spin label, 1-L-glutamate-5-N-(1-oxyl-2,2,6,6-tetramethyl-4-aminopiperidinyl)-i,4-dinitrobenzene, has been used to probe the relative binding specificity of a single anionic ligand site on bovine alpha-fetoprotein (AFP) to arachidonate, bilirubin, docosahexaenoate, and plamitate. The binding isotherm of the spin label with AFP, as shown by a Scatchard plot, indicates the presence of a single high affinity binding site. The site-site relationship of the four endogenous ligands, arachidonate, bilirubin, docosahexaenoate, and palmitate, was determined by studying their effectiveness in competing for this anionic ligand binding site on AFP. Scatchard plots of the spin label in the presence of 1 to 3 molar equivalents of arachidonate, bilirubin, and docosahexaenoate and up to 6 molar equivalents of palmitate have been determined. The effectiveness of the four endogenous ligands in displacing the spin label from its primary binding site is bilirubin greater than or equal arachidonate approximately equal to docosahexaenoate greater than palmitate. These results indicate that polyunsaturated essential fatty acids and bilirubin share a high affinity binding site on AFP. We propose that the function of this anionic ligand binding site on AFP is for the transport of bilirubin and polyunsaturated fatty acids in fetal serum, as well as for the cross-placental transfer of this metabolite and of essential fatty acids.

Animals↗
PubMed1980

Osteosarcoma and acute myeloblastic leukemia after therapy for childhood Hodgkin disease - a case report.

A child diagnosed with Stage IVB Hodgkin disease at nine and one-half years of age subsequently developed osteosarcoma and acute myelogenous leukemia ten years after her initial diagnosis. She received multiple courses of radiotherapy and several single chemotherapeutic agents for her Hodgkin disease. Theraphy-induced multiple malignancies and intrinsic predisposition to carcinogenesis in this case is discussed.

Antineoplastic Agents↗
PubMed1980

Biochemical, pharmacological, and phase I clinical evaluation of pseudoisocytidine.

Pseudoisocytidine (psi ICyd) is a C-nucleoside with enhanced stability and resistance to enzymatic deamination when compared to 5-azacytidine and 1-beta-D-arabinofuranosylcytosine. Elimination kinetics in plasma using [14C]psi ICyd showed a beta-phase for t1/2 for 14C of 2 hr and a beta-phase t1/2 of unchanged psi ICyd of 1.5 hr. Net recovery of radioactivity in urine over 24 hr varied between 40 and 80% of the administered dose; 50 to 90% was unchanged drug and the rest was pseudouridine. Human leukemic cells in vitro deaminated psi ICyd very slowly, formed appreciable quantities of pseudoisocytidine triphosphate, and incorporated small amounts into RNA and DNA. Clinical trials were done using a daily i.v. injection for 5 consecutive days. Hematological or intestine toxicities were not seen, nor was depression of white blood cell count observed in leukemic patients. Hepatic toxicity proved to be dose limiting; this was characterized by an early phase with elevation of prothrombin time and aspartate aminotransferase. A later phase with cirrhosis was observed in two patients. Autopsy showed massive hepatic necrosis in patients dying of acute toxicity and micronodular cirrhosis in one patient dying with the chronic form.

Antineoplastic Agents↗
PubMed1979

Vindesine. A review of phase-II trials.

Vindesine is a new vinca alkaloid with broad-spectrum antineoplastic activity in experimental tumor models. Phase-I studies have shown that a weekly dosage regimen of 3--4 mg/m2 IV produces manageable toxicity, with leukopenia and peripheral neuropathy being dose-limiting. Two hundred seventy-five patients have been enlisted in Phase-II trials at the Memorial Sloan-Kettering Cancer Center. Major objective responses (complete and partial remissions) were seen in bronchogenic carcinomas, melanoma, testicular carcinoma, esophageal carcinoma, acute lymphocytic leukemia, malignant lymphoma (Hodgkin's and non-Hodgkin's) and Wilms' tumor. Patients with hematologic and germ cell neoplasms were treated on a daily administration schedule (1.0--1.3 mg/m2 IV for 5--7 days). Vindesine was well tolerated, with less than 5% of patients having a WBC nadir of less than 1000 cells/mm3 and with a platelet-sparing effect noted. Dose-related peripheral neuropathy occurred frequently and was generally mild to moderate in degree. Vindesine appears to be an active agent whose role will be further defined by completion of ongoing trials.

Blood Cell Count↗
PubMed1979

Gallium scan in recurrent Hodgkin's disease in children.

In 18 of 88 children with biopsy proven and previously untreated Hodgkin's disease, recurrence developed during a period from four to 53 months after therapy (median period, 22 months). In 16 patients in whom gallium scans were performed, 21 positive gallium scans were obtained during 26 episodes of recurrence. Abnormalities were noted in half of them during a period from one to 10 months prior to physical, laboratory, radiographic or histologic confirmation of recurrence (median period about 5 months). We have concluded that the gallium scan is very useful in initial workup and is sensitive in detecting early recurrence in children with Hodgkin's disease. Such scans are indicated when there is clinical suspicion of recurrence, when other modalities are unavailable or when the results of other studies are equivocal.

Adolescent↗
PubMed1979

Work performance of rehabilitated psychiatric patients--a comparative study.

View Road Hospital (VRH) was commissioned on 1st August 1975 with the main objective of providing intensive rehabilitation and training for male long-stay mental patients from Woodbridge Hospital. The aim was to train and prepare them for work outside the hospital. This paper examines the work performance of the 38 patients who have been phased out to work since the commissioning. A matched group of 38 male patients undergoing similar rehabilitative schemes in Woodbridge Hospital and placed in similar open employment was selected for comparison. Contrary to expectation, the VRH patients did not perform significantly better than the Woodbrige Hospital's patients. Some of the probable reasons for this discrepancy, and their implications for psychiatric rehabilitative services in general, are discussed.

Adult↗
PubMed1979

Phase I trial of chlorozotocin.

Chlorozotocin was given to 37 patients with advanced malignant tumors in a daily X 5 schedule at 6-week intervals. Total iv doses for each course ranged from 75 to 200 mg/m2. Myelosuppression was dose-limiting, with a platelet count depression regularly observed at doses of greater or equal to 150 mg/m2; leukopenia occurred only at the highest dose level. Nausea and vomiting were mild and uncommon. No hyperglycemia or adverse drug-related effects on renal or hepatic function were observed. No major antitumor activity occurred; however, three patients with renal cell carcinoma and one patient each with lung cancer, ovarian carcinoma, and Hodgkin's disease had minor objective decreases in tumor size. A dose range of 150--200 mg/m2 iv for each 5-day course is recommended for phase II studies.

Adolescent↗
PubMed1979

Phase I evaluation of tetrahydrouridine combined with cytosine arabinoside.

In conventional clinical use, cytosine arabinoside (ara-C) is rapidly deaminated by pyrimidine nucleoside deaminase to the nontoxic compound uracil arabinoside. Tetrahydrouridine (THU) effectively inhibits this enzymatic degradation but is by itself nontoxic. This study demonstrates that concomitant administration of THU markedly increases the myelosuppressive potency of ara-C. When 25 or 50 mg/kg of THU iv and 0.1--0.2 mg/kg of ara-C iv are given daily x 5 days, they produce moderate-to-severe leukopenia and mild-to-moderate thrombocytopenia. A dose of 25 mg/kg of THU with 0.1 mg/kg of ara-C iv daily x 5 days appears appropriate for phase II studies; it produces myelosuppression equivalent to that produced by 3 mg/kg/day x 5 days of ara-C alone. No toxicity occurred with this combination that would not have been expected from ara-C given alone in an equitoxic dose. Although THU and ara-C produced a reduction in peripheral blood and bone marrow blast cells in eight of nine patients with acute leukemia, bone marrow remission did not occur in any of these heavily pretreated patients.

Bone Marrow↗