Biomedical subjects
Publications and source records attributed to S H Woo.
A new bithiazole, KR-025 (1), was isolated from Myxococcus fulvus. Its structure was elucidated by spectroscopic analysis. In addition to 1, the strain produced relatively large quantities of a second, closely related antibiotic, myxothiazol. These compounds demonstrated potent cytotoxicity against human tumor cells.
We have reconstructed thumb defects using microsurgical techniques in 43 patients. The flap survival was 100% and functional improvement with near normal appearance was obtained in the reconstructed thumbs. In order to obtain satisfactory results, donor sites were confined to the great toe and its adjacent structures and adventitia was removed from the vascular pedicle, which was transferred by subcutaneous tunnelling to minimize scar formation in the reconstructed thumb. The width of transferred nail and pulp volume were matched to the defect in the thumb before transfer.
Owing to its unique anatomic arterial supply and dual nerve innervation, the first web space of the foot can be used to harvest various sizes and shapes of flaps, which the authors have classified into four types according to their usage in hand reconstruction. This in turn depends on the site, shape, and size of the soft-tissue defect in the hand. Web skin flaps (n = 8) were used in prevention of contracture in the first web space and for proximal finger reconstruction. Two-island skin flaps (n = 4) were used to resurface the pulp defect in two adjacent fingers. In severe adduction contracture of the first web space, fill-up web flaps (n = 10) were used to replace the volume defect after a release procedure in the hand. Adjuvant web flaps (n = 9) were used in wrap-around procedures, in dorsalis pedis flap transfer, and in vascularized joint transfer to supplement the main flaps and to restore sensation in the reconstructed area. In the past 10 years up to February of 1998, a total of 31 patients with soft-tissue defects in the hand and fingers were reconstructed using the web space free flap with flap survival rate of 100 percent. The mean static 2-point discrimination was 8.5 (7.2 to 10) mm, and the mean first web angle was 86 degrees. The advantage of the first web space flap from the foot is that it can easily be harvested to match various sizes and shapes of defects in the hand and fingers. In addition, because of the anatomic similarity in contour, thickness, texture, and nerve innervation with the hand, the sensory restoration is excellent with minimal morbidity at the donor site. By classifying the flaps into four types according to various sizes, shapes, and the site from which the flap are harvested, clinical usefulness in various types of hand and finger reconstruction was confirmed.
On the basis of a mechanistic understanding of the mode of action of artemisinin-like antimalarials, a series of structurally simple 3-aryl-1,2,4-trioxanes 5 was designed and was prepared in three to five operations from commercial reactants. The 3-aryl group was attached in each case as a nucleophile. In an electronically complementary fashion, 3-(fluoroalkyl)-trioxanes 6 were prepared via attachment of electrophilic fluoroalkyl esters. Both in vitro and in vivo antimalarial evaluations of these new trioxanes showed 12 beta-methoxy-3-aryltrioxanes 5g, 5j, 5k, and 51 to be highly potent, with crystalline fluorobenzyl ether trioxane 5k especially potent even when administered to rodents orally. As shown by rearrangement of hexamethyl Dewar benzene into hexamethylbenzene, iron-induced degradation of some of these 3-aryltrioxanes 5 involves generation of high-valent iron oxo species that might kill malaria parasites.
An ethanol extract of Psoralea corylifolia caused strong DNA polymerase inhibition in a whole cell bioassay specific for inhibitors of DNA replication enzymes. Bioassay-directed purification of the active compounds led to the isolation of the new compound corylifolin (1) and the known compound bakuchiol (2) as DNA polymerase inhibitors. On the basis of the structures of 1 and 2, resveratrol (3) was tested and found to be active as a DNA polymerase inhibitor in this bioassay. Neobavaisoflavone (4) was isolated as a DNA polymerase inhibitor, daidzein (5) as a DNA polymerase and topoisomerase II inhibitor, and bakuchicin (6) as a topoisomerase II inhibitor.
The great toe partial-nail preserving transfer technique is another modification for distal thumb reconstruction in composite defects at or below the interphalangeal joint of the thumb. Noting the size difference of the nail width between the great toe and thumb, the authors dissected only a thumb nail width and skin flap from the great toe, leaving the remainder of the medial skin flap and nail of the great toe at the donor site. A total of 25 cases between 1993 and 1996 were performed using this technique, and the mean follow-up period was more than 12 months. The reconstructed thumb had a better cosmesis with a more natural appearance. At long-term follow-up, the thumb nail width decreased an average of 1.8 mm, but the pulp volume was almost the same as that of the normal contralateral side. The average static 2-point discrimination was less than 9.0 mm. In cases with preserved interphalangeal joint, an average of 48 degrees of range of motion with key-pinch of 80 percent of that of the normal contralateral thumb was achieved. The final appearance of the donor site with partial nail looks like a brachymetatarsia.
The purpose of this study was to evaluate further factors that could explain the survival mechanism in the arterialized venous flap. The authors used 16 canines to investigate the survival rate and pattern of the arterialized venous flap and compared the results with those of the conventional saphenous flap. The number and distribution of draining veins in the arterialized venous flap group were varied to observe their impact on the survival rate and pattern. Gross examination of venous network, blood gas, venogram, blood pressure, and histologic study were also carried out. Although there was no significant difference in final survival rate between conventional flap and arterialized venous flap with two efferent veins (p > 0.01), that of the arterialized venous flap increased significantly as the number of draining veins increased. Blood gas analysis showed that more effective oxygen consumption took place when the number of draining veins increased. By measuring the blood flow and volume at 8 hours after the operation with a laser Doppler flowmeter, it was possible to predict the necrosis of the arterialized venous flap. Attachment to a high pressure arterial blood flow system induced smooth muscle proliferation and neogrowth of elastic fibers in the veins. Furthermore, progressive narrowing of the lumen hastened the development of a collateral circulation, demonstrated on a venogram by the tortuous vessels and neovascularization up to the flap margin. To make it possible to predict and achieve complete survival of the arterialized venous flap, the following criteria must be considered: (a) an arterialized venous flap should be designed to contain most of the venous network in the center, (b) the arterial inflow has to be anastomosed to one afferent vein, (c) two or more efferent veins should drain the arterialized venous flap.
The cytotoxic oxoaporphine alkaloid liriodenine, isolated from Cananga odorata, was found to be a potent inhibitor of topoisomerase II (EC 5.99.1.3) both in vivo and in vitro. Liriodenine treatment of SV40 (simian virus 40)-infected CV-1 cells caused highly catenated SV40 daughter chromosomes, a signature of topoisomerase II inhibition. Strong catalytic inhibition of topoisomerase II by liriodenine was confirmed by in vitro assays with purified human topoisomerase II and kinetoplast DNA. Liriodenine also caused low-level protein-DNA cross-links to pulse-labeled SV40 chromosomes in vivo, suggesting that it may be a weak topoisomerase II poison. This was supported by the finding that liriodenine caused topoisomerase II-DNA cross-links in an in vitro assay for topoisomerase II poisons. Verapamil did not increase either liriodenine-induced protein-DNA cross-links or catalytic inhibition of topoisomerase II in SV40-infected cells. This indicates that liriodenine is not a substrate for the verapamil-sensitive drug efflux pump in CV-1 cells.
The bis(2,6-dioxopiperazine)s are a structurally and mechanistically unique class of topoisomerase II inhibitors that do not bind DNA and that do not stabilize topoisomerase II-DNA strand passing intermediates ("cleavable complexes"). The most effective topoisomerase II inhibitor in the bis(2,6-dioxopiperazine) series is ICRF-193 (meso or S*, R* isomer), with a meso 2,3-butanediyl linker connecting the dioxopiperazine rings. The two enantiomeric diastereomers, (R,R) and (S,S), of ICRF-193 possessing the two optically active 2,3-butanediyl linkers have been prepared from their respective optically pure 2,4-diaminobutanes via 2,3-diaminobutane-N,N,N',N'-tetraacetic acid, esterification, and imide formation. Both in vivo and in vitro assays for catalytic inhibition of topoisomerase II were employed to show that the (S,S)- and (R,R)-isomers are almost inactive as topoisomerase II inhibitors. The data indicate that the meso stereochemistry of the alkanediyl linker is crucial for activity and provides additional evidence that the cytotoxicity of the bis(2,6-dioxopiperazine)s is due to their ability to inhibit topoisomerase II.
Skin flaps nourished by arterial blood entering through the venous network were applied in 12 cases of relatively large skin defects of the hand. The flaps showed remarkable oedema and multiple bullae on their surface from the second to the 14th postoperative day, but partial necrosis of the flap only developed in three cases. The free arterialized venous flap is a useful procedure for resurfacing relatively large skin defects of the hand.
Although worldwide incidence is not well known, foreign-body injection is often attempted in order to increase the circumference of the penile shaft. Paraffin, Vaseline, and other materials are injected into the penile skin by the patient himself or by untrained persons who practice medicine fraudulently. Complications usually follow, such as penile deformity, skin necrosis, limited erectile function, and the inability to have intercourse. Definitive treatment of these patients includes the complete removal of skin and subcutaneous tissue infiltrated by the foreign material. Sometimes, complete removal of the foreign material may not be possible and may leave permanent foreign-body granuloma on the corpus cavernosum and/or corpus spongiosum. The remaining foreign material does not permit skin-graft coverage, which is a simple and effective method of resurfacing. In such cases, we tried a new technique comprised of bilateral scrotal flaps to provide for reliable and stable coverage. The scrotal skin, which has high elasticity, seems to be a good material for penile coverage, despite its hairy nature. In our experience, exclusively with Korean males, the scrotal hair has a low density and does not seem to cause serious problems, but patients with hirsute scrotal may be contraindicated. Since 1993, 17 patients with penile paraffinoma have been treated using the bilateral scrotal flap method. All 34 flaps survived completely and the reconstructed penis had immediate postoperative tactile sensibility. The results were successful and without any major complications.
This study was done to gather the basic information needed to identify how the home nursing care needs and implementation of self care is being carried out for chronically ill patients. The subjects of the study were 294 from chronically ill patients in a general hospital, a university hospital and seven primary health care center and the data was collected by a nurses, public health nurse practitioners using questionnaires from July 30 to September 30, 1993. The data were analyzed using percentage, mean, and T-test, ANOVA. Our objectives were to understand basic nursing information general characteristics, implementation of self care, home nursing care needs, implementation of self care depend on general characteristics. The results of the study were as follows 1) General characteristics of subjects. The majority of subjects are female (54.8%); 66.7% of residence are fishing and agrarian villages. 20.1% of disease are neurologic system (backache, neuralgia, HIVD, C.V.A). 2) Environmental offord reveals high point in implementation of self care (2.76 +/- 1.37); 3) B.P check reveals high percentage in home nursing care needs. (84.7%); 4) Implementation of self care depend on general characteristics reveals significantly different by sex*, educational level**, monthly income**, number of family*, disease*, and reason of untreatment** (* < 0.05, ** < 0.01). In conclusion the study requires efforts of nurse practitioners, and the support of useful resources by government.