Biomedical subjects
T Tan
Publications and source records attributed to T Tan.
[Hepatic carcinoma treated by hepatic arterial embolization using 131I and chemotherapeutic agent gelatin microspheres: report of 9 cases].
Nine patients with inoperable hepatoma were treated by using hepatic arterial embolization 131I and chemotherapeutic agent gelatin microsphere (131I-CA-GM). The emission CT after operation detected that the microspheres were concentrated on tumor area. The ratio between the radioactivity in tumor and that in liver was 4.1:1. A case died of ictopic embolization; the others survived 3, 4, 5, 19, 24, 7, 8, and 12 months respectively. Three of them were still alive. 131I-CA-GM has triple anticarcinogenic actions, including the arterial occlusion, targeting chemotherapy and internal radiation. The microspheres can selectively accumulate in the tumor artery and can be easily traced by gamma-camera or emission CT. 131I-CA-GM is a hopeful embolic agent for the treatment of liver cancer, but some problems about ectopic arterial embolization should be further studied.
Characterization of the performance of shoe insert materials.
It has been widely reported that shoe inserts are an effective interventional modality either for the relief of discomfort to the feet associated with a variety of orthopedic disorders or conditions or simply for comfort. Results from many types of experimental tests have been used to obtain the shock absorption capacity of shoe insert materials. The authors contend in this study that, while shock absorption is a highly desirable property, it is by no means the only that should be used to characterize these materials. Thus, a new index of performance of these materials is proposed. This index is computed from data, obtained in a simple experimental test, on both the shock absorption and energy return performances of the insert material.
[Study of the mechanism of gastrodin and derivatives of gastrodigenin].
The tritiated alpha-isobutylhydroxybenzyl alcohol (3H-G018) was found to be able to bind benzodiazepine (BZ) receptor on the rat brain membrane. The 125I labeled G-018 also had the similar binding activity with this receptor. In the present investigation, we observed that gastrodigenin and its derivatives inhibited the 125I-G018 binding of BZ receptor competitively, but no inhibition was observed with gastrodin. The results suggested that Gastrodigenin was bound to BZ receptor, and otherwise, gastrodin would have no direct interaction with BZ receptor. Probably, it might metabolize into gastrodigenin in vivo, and then got through the blood brain barrier and bound to BZ receptor, which mediated its pharmacological effects on the central nervous system.
[An experimental study on hepatic arterial embolization with 131I-MMC-GM].
We designed a new gelatin microsphere (GM, 65 micron in diameter), which could combine with mitomycin C and 131I. The test in vitro showed that the GM had excellent drug release effect. Hepatic arterial embolization was carried out in 6 dogs with 131I-MMC-GM. The dogs survived from 4 to 28 days before being killed. Scintigraphy indicated that high radioactivity was concentrated in the liver, but was very low in the blood and thyroid. Pathologic study found that the GM was trapped in hepatic arterioles. The GM was eliminated by foreign body giant cells and the lumen of arterioles was occupied by granulations 14-28 days after operation. 131I-MMC-GM is a multiple anticancer agent which can exert triple action of targeting chemotherapy, internal radiotherapy and arterial embolization.
[Synthesis of hexamethyl propylamine oxime and comparative study of its diastereoisomers].
This is a report on the synthesis of hexamethyl-propylene-amine oxime (HM-PAO), a new agent for regional cerebral blood flow (gamma CBF) imaging, the separation of its diastereoisomers (dl- and meso-HM-PAO), and a comparative study of three forms of Tc- 99m labelled HM-PAO (dl-, meso- and mixture-) in chromatography, mice biodistribution and rabbit imaging. The results showed that the Rf value of Tc-99m-dl-HM-PAO (0.8-1.0) on silica G thin layer chromatography with MEK as solvent was different from that of Tc-99m-meso-HM-PAO (0.6-0.8), and that the retention of dl- isomer in the brain was higher and more static than those of meso-and mixture HM-PAO but identical with Ceretec, a dl-HM-PAO kit manufactured by Amersham Inc., England. The primary clinical applications for gamma CBF SPECT imaging demonstrated a satisfactory result.
[Galactosyl neoglycoalbumin:preparation and studies of its binding with hepatic special receptor].
Galactosyl-neoglycoalbumin (NGA) can bind with the asialoglycoproteins receptor specifically on the surface of mammal's liver. We prepared NGA in different carbohydrate density and made some animal and clinical tests with technetium-99m labeled NGA. The maximum absorption of 99mTc-NGA-21 was 82.6% in liver. We also got the satisfactory radiographs of liver. NGA was synthesized by the covalent coupling of a carbohydrate bifunctional reagent, 2-imino-2-methoxyethyl-1-thio-galactose (4), to human serum albumin. The cyanomethyl-1-thio-glycoside of beta-D-galactose (3) was prepared from the pseudothiourea derivative (2) which was synthesized by acetylation, bromination and substitution of galactose (3) could be converted to (4) by treatment with sodium methoxide.
Enhanced penetration of zona-free hamster ova by sperm prepared by Nycodenz and Percoll gradient centrifugation.
The effect of sperm penetration capacity after selection procedures using Percoll (Pharmacia AB, Uppsala, Sweden) and Nycodenz (Nycomed Diagnostics, Oslo, Norway) gradient centrifugation was compared with double-washed and swim-up in 47 subfertile men. The results of sperm motility, velocity, and amplitude lateral head displacement showed no significant improvement with the centrifugation procedures. The sperm penetration assay results obtained with double-washed and swim-up technique were poor (2.7% +/- 1.7%), however, a significant enhancement was obtained by Percoll (16.3% +/- 3.7%) and Nycodenz (15.8% +/- 3.3%) processing. Nycodenz centrifugation allowed sperm penetration of zona-free hamster ova at comparable rates to Percoll separation.
The use of electroejaculation and zygote intrafallopian transfer to achieve a pregnancy after a major gunshot wound to the abdomen: a unique application.
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[Analgesic activity of morphine suppository in rats].
Analgesic activity of morphine administered rectally as a suppository was investigated in rats in order to ascertain analgesic activity of morphine suppository. Morphine hydrochloride given rectally as a suppository produced analgesic activity in a dose-related manner in the tail pressure and acetic acid-induced writhing tests, and its potency (ED50 = about 17 and 0.689 mg/kg, respectively) was approximately twice that of morphine hydrochloride administered orally as an aqueous solution. The analgesic action was as durable as that of oral morphine, but its onset was faster. The plasma and brain levels of morphine reached peak until 30 min after rectal administration of morphine suppository, and these time-courses approximately corresponded with that of the analgesic action. These results suggest that morphine given rectally to rats as a suppository produces analgesic action equivalent or superior to orally administered morphine after absorption from the rectum.
[Morphine hydrochloride suppositories. I. Bioavailability of morphine hydrochloride suppositories in rats].
Bioavailabilities of morphine after rectal administration of three different morphine-HCl suppositories (5 mg/kg) were evaluated in rats. The suppositories were prepared with three fatty bases (Witepsol H-15, Witepsol W-35, Suppocire AT) by the fusion method. The plasma and brain concentrations of morphine and its metabolites, morphine-3-glucuronide and morphine-6-glucuronide, were determined by high-performance liquid chromatography. The bioavailabilities of morphine after rectal administration were compared with those after intravenous and oral administration of morphine.HCl solution (5 mg/kg). The plasma levels of morphine after rectal administration of morphine.HCl solution were higher than those after oral administration, whereas the plasma levels of metabolite, morphine-3-glucuronide was lower than those after oral administration. Morphine after rectal administration of Witepsol H-15 suppository released more easily than other suppositories. The inter-animal variation in the plasma levels of morphine after rectal administration of Witepsol H-15 suppository was smaller than those of other suppositories. Results obtained in this study indicate that morphine.HCl suppository prepared with Witepsol H-15 is a promising material as preparation of suppositories.
[Morphine hydrochloride suppositories. II. Bioavailability of morphine hydrochloride suppositories in dogs].
Bioavailabilities of morphine after rectal administration of three different morphine.HCl suppositories were evaluated in dogs, whose rectum was lavaged or non-lavaged. The suppositories were prepared with three fatty bases (Witepsol H-15, Witepsol W-35, Suppocire AT) by the fusion method. The release of morphine from the suppositories was examined after stored for two weeks at 30 degrees C. The plasma concentrations of morphine and its metabolites, morphine-3-glucuronide and morphine-6-glucuronide, were determined by high-performance liquid chromatography. The bioavailabilities of morphine after rectal administration were compared with those after intravenous and oral administration of morphine++.HCl solution. In the case of rectal lavaged dogs, the plasma levels of morphine after rectal administration of morphine.HCl solution were higher than those after oral administration of morphine.HCl solution. The release of morphine from Witepsol H-15 suppository was more rapid than those from other suppositories. Morphine after rectal administration of Witepsol H-15 suppository was rapidly absorbed in the rectum, and the inter-animal variation of its plasma levels was smaller than those of other suppositories. In rectal non-lavaged dogs, the bioavailabilities of morphine after rectal administration of morphine.HCl solution and suppositories decreased more than those of rectal lavaged dogs. Although the bioavailability of morphine after rectal administration of morphine.HCl was decreased by the influence of contents in the rectum, morphine from Witepsol H-15 suppository was more rapidly absorbed in the rectum, and the inter-animal variation of its plasma levels was smaller. These results indicate that, among their suppositories, Witepsol H-15 suppository is available for the terminal care of malignant disease.
HLA and allopurinol drug eruption.
Strong HLA associations were found in Southern Chinese patients with skin eruptions due to allopurinol. The positive associations were with AW33 (Pc = 1.7 x 10(-5); relative risk [RR] = 15.0, 95% confidence limit 5.2-42.9) with B17/BW58 (Pc = 2.9 x 10(-9); RR = 46.3, 95% confidence limit 10.3-209.2). The negative association was with A2 (Pc = 8.3 x 10(-5), RR = 0). The findings suggested a genetic predisposition to cutaneous drug reactions.
Characteristics of the gastrointestinal absorption of morphine in rats.
The absorption characteristics of morphine were investigated by using rat gastrointestine. Absorption and transport experiments were carried out by the in situ loop and the in vitro everted sac methods, respectively. Brush border membrane vesicles (BBMVs) were used for uptake experiments. Morphine and its metabolites, morphine-3-glucuronide (M-3-G), and morphine-6-glucuronide (M-6-G), in biological samples were simultaneously determined by high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection and electrochemical detection. In the in situ loop method, morphine was well absorbed in the order of jejunal site greater than duodenal site greater than ileal site greater than middle intestinal site greater than rectal site, but it was poorly absorbed from the stomach. In each of the everted duodenal and jejunal sacs, 2,4-dinitrophenol, a metabolic inhibitor, inhibited the transport of morphine from the mucosal side to the serosal side. Further, HgCl2 pretreatment reduced the absorption of morphine from the duodenal and the jejunal loops. The initial uptake of morphine by BBMVs was stimulated in the presence of an H+ gradient (inner pH 7.5 and outer pH 5.0) and an overshoot phenomenon was observed. The initial uptake showed concentration dependence, i.e., it was saturable. Results obtained in this study indicate that carrier-mediated transport stimulated by the H+ gradient is partly involved in the duodeno-jejunal absorption of morphine, although morphine is passively absorbed from other sites.
Comparative double-blinded study between mupirocin and tetracycline ointments for treating skin infections.
A double-blinded study was conducted to compare the effects of mupirocin and tetracycline ointments in the treatment of skin infections. 111 patients were available for clinical assessment, of which 53 were treated with mupirocin and 58 treated with tetracycline. Clinically, both groups were improved, and there was no significant difference. Bacteriological assessment however revealed a better response to mupirocin. Staphylococcus aureus and Streptococcus pyogenes were the most common organisms isolated. 99% of Staphylococci were sensitive to mupirocin compared with 61% to tetracycline and 29% to penicillin G. 57% of Group A beta haemolytic Streptococci were resistant to tetracycline compared to 14% to mupirocin. Gram-negative organisms were mostly resistant to both preparations. No side effects were observed in both treatment groups. This study suggests that mupirocin is a safe and effective topical preparation for treating most of our common skin infections.
Endocervical chlamydial infection in female contacts of patients with nongonococcal urethritis.
Eighty-five female contacts of patients with nongonococcal urethritis attending Middle Road Hospital were examined. Chlamydia trachomatis was isolated from the cervix in 39% of them. Forty-five per cent of the chlamydia-positive patients were asymptomatic and 79% of them showed signs of a cervicitis. None of the patients developed complications. Neisseria gonorrhoeae was not isolated from any of the patients. Clinical markers other than cervicitis are not useful for detecting chlamydial infections in female contacts of NGU. Until such time when cheaper, more convenient and accurate methods of laboratory diagnosis of C. trachomatis are put to routine use, it would seem prudent to treat all female contacts of NGU patients after exclusion of other sexually transmitted diseases.
Levels of steroid and protein hormones in antral fluids of women treated with different combinations of gonadotropins, clomiphene citrate, and a gonadotropin-releasing hormone analog.
Levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol, progesterone (P), and total protein in follicular fluids collected from 18 patients pretreated with a gonadotropin-releasing hormone analog (GnRHa), in association with human menopausal gonadotropin (hMG) and FSH, were compared with values for 69 patients treated with FSH, hMG, FSH/hMG, or clomiphene citrate (CC)/hMG in an in vitro fertilization (IVF) program. The authors have established a number of significant differences in chemical and physical properties of follicular fluids of patients treated by different regimen, and concur with earlier evidence that the volume of a follicle, and its P and total protein content, are related to the maturity of the oocyte nested within the follicle. Overall, however, differences in concentrations of gonadotropins in follicular fluids between groups were not consistent with differences in follicular fluid steroid levels, and levels of immunoactive gonadotropins in follicular fluids were not in accord with dosages of exogenous immunoactive gonadotropin administered during hyperstimulation. The most favorable outcomes of IVF (greater than 70% of oocytes fertilized) were established with oocytes collected from patients treated with FSH only or with CC/hMG, and patients treated with FSH only yielded the highest average number of oocytes which fertilized in vitro (6.2 per patient).
Prophylaxis against infection in Singaporean prostitutes.
One hundred prostitutes were interviewed about the prophylactic measures they took against infection. The use of contraceptive diaphragms and clandestine antibiotics correlated significantly with fewer gonococcal infections.