The modification of a radiation lesion in animals with an aqueous extract of Hypericum perforatum L. 2.]

The preparation Hypericum perforatum L. has been shown to decrease the intensity level of enzymatic and non-enzymatic processes of lipid peroxidation of rat liver microsomes in vitro and in vivo. In the mucus of the this intestine in vivo the increase of the number of non-enzymatic SH-groups is observed. Possible mechanisms of radioprotective action of the preparation is under discussion.     

An immunofluorescence study of the effects of ultraviolet radiation on the organization of microfilaments, keratin intermediate filaments, and microtubules in human keratinocytes.

Indirect immunofluorescence microscopy has been used to investigate the ultraviolet (UV) radiation induced disruption of the organization of microfilaments, keratin intermediate filaments, and microtubules in cultured human epidermal keratinocytes. Following irradiation, concurrent changes in the organization of the three major cytoskeletal components were observed in cells incubated under low Ca2+ (0.15 mM) conditions. UV irradiation induced a dose-dependent condensation of keratin filaments into the perinuclear region. This collapse of the keratin network was accompanied by the reorganization of microfilaments into rings and a restricted distribution of microtubules, responses normally elicited by exposure to high Ca2+ (1.05 mM) medium. The UV induced alteration of the keratin network appears to disrupt the interactions between keratin and actin, permitting the reorganization of actin filaments in the absence of Ca2+ stimulation. In addition to the perinuclear condensation of keratin filaments, UV irradiation inhibits the Ca2+ induced formation of keratin alignments at the membrane of apposed cells if UV treatment precedes exposure to high Ca2+ medium. Incubation of keratinocytes in high Ca2+ medium for 24 hours prior to irradiation results in the stabilization of membrane associated keratin alignments and a reduced susceptibility of cytoplasmic keratin filaments to UV induced disruption. Unlike results from investigations with isogenic skin fibroblasts, no UV induced disassembly of microtubules was discernible in irradiated human keratinocytes.     

A case of anisakiasis causing intestinal obstruction

A 31-year old salesman living in Seoul developed suddenly abdominal pain due to intestinal obstruction. Exploratory laparotomy exhibited segmental jejunal cellulitis caused by penetrating Anisakis larva. The patient had eaten raw fish. The typical history of intestinal anisakiasis was presented with a short review of Korean patients of anisakiasis.     

A single-stage two-flap method of total ear reconstruction

A single-stage two-flap method of total ear reconstruction in congenital microtia is reported. This method was derived from the one-stage reconstruction described by Song and Song. Two flaps defined by vascular basis were elevated on the mastoid area: the superficial skin flap supplied mainly by subcutaneous pedicled arteriole perforators from the posterior auricular artery and the deeper axial-pattern fascial flap including the posterior auricular artery itself. The ear framework, exaggeratedly carved using autologous rib cartilage, could be inserted easily between the two flaps, simultaneously producing the auriculocephalic angle and the conchal wall. Intraoperative expansion of the skin flap and postoperative external ear molding also were performed to create aesthetically pleasing ears.     

High level expression of human tissue-type plasminogen activator gene in mouse C127 cell.

We have expressed human tissue plasminogen activator (t-PA) gene at high levels in a mouse cell line. The t-PA cDNA with deletion of the long 3' untranslated region was inserted into a bovine papilloma virus (BPV) derived vector under the control of a mouse metallothionein promoter. The mouse metallothionein (mMT) gene also provided signals for splicing and polyadenylation. Mouse C127 cells transfected with this construct secreted t-PA at high levels into the cell culture medium. When an SV40 polyadenylation signal was inserted between the t-PA cDNA and the mMT splicing signals, the expression level increased by several fold. The expression levels did not increase further upon either introduction of Rous sarcoma virus LTR into the plasmid or mutation of the translation initiation context sequence to conform with the consensus one. Most of the plasmid appears to be integrated into the host chromosome. Cells producing high levels of t-PA tend to detach from the dish in a few days after passage. When grown on porous microcarriers, however, such cells can be maintained in culture for months and t-PA can be harvested continuously.     

Recent data on estrogen sulfatases and sulfotransferases activities in human breast cancer

Of the total number of breast cancers approx. 30-50% are hormone-dependent and estradiol is one of the main factors of cancerization. Consequently, the control of this hormone inside the cancer cell is of capital importance because it is well established that the inhibition of estradiol biosynthesis can have a positive effect on the evolution of the disease. The blockage of estradiol can be obtained by the action of anti-aromatases, anti-sulfatases, the control of the 17 beta-hydroxysteroid dehydrogenase activity or by the stimulation of the sulfotransferase which converted the estrogens in their sulfates. In breast cancer tissue estrone sulfate is quantitatively the most important source of estradiol. In the intact cell, estrone sulfatase activity is very intense in the hormone-dependent cell lines (e.g. MCF-7, T-47D) but very small activity is observed in the hormone-independent (e.g. MDA-MB-231, MDA-MB-436) cell lines. However, this activity became very strong after homogenization in the hormone-independent cells, suggesting the presence of repressive factor(s) for this enzyme or its sequestering in an inactive form, in the intact cells of these cell lines. In a series of previous studies it was found that in hormone-dependent cell lines different anti-estrogens: tamoxifen and derivatives, ICI 164,384, very significantly decrease the estradiol concentration originated from estrone sulfate, and recently it was observed that Decapeptyl (D-Trp6-gonadotropin-releasing hormone) in the presence of heparin can also decrease the conversion of estrone sulfate into estradiol. No significant effect was obtained in the presence of heparin or Decapeptyl alone. The estrone sulfatase activity can be inhibited by progesterone, the progestagen R-5020, and testosterone. In another series of recent studies the presence of very strong estrogen sulfotransferase activity has been shown in one breast cancer cell line, the MDA-MB-468. We can conclude that: (1) the control of estradiol concentration can be carried out in the breast cancer tissue itself; (2) estrone sulfate can play an important role in the bioavailability of estradiol in the breast cancer cell; and (3) as is the case for the aromatase, the control of: the estrogen sulfatase, estrogen sulfotransferase, and 17 beta-hydroxysteroid dehydrogenase can be new targets for therapeutic applications in breast cancer.     

Effects of T-2 toxin and its congeners on membrane functions of cultured human fibroblasts

Cytotoxicity of T-2 toxin, HT-2 toxin, acetyl T-2, neosolaniol, and T-2 tetraol was compared between normal human fibroblasts and mutant I-cell human fibroblasts, which only produce 10 to 15% of lysosomal hydrolases present in normal fibroblasts. Both cleavage of 3-(4, 5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and cell count by hemocytometer were used for evaluations. For all toxins, dose-related effects on both types of cultures were evident. Cytotoxicity of the above mycotoxins on both cell lines were similar, indicating that lysosomal enzymes were not involved in the toxicity of T-2 toxin and its congeners. An inhibitor of lysosomal cysteine proteases (E-64) did not alter the cytotoxicity of T-2 toxin. The decreasing order of toxicity was T-2 toxin, HT-2 toxin, neosolaniol, acetyl T-2 toxin, and T-2 tetraol in both cell lines. When normal human fibroblasts were loaded with the fluorescent dye Lucifer yellow CH (LY), a subsequent treatment of T-2 toxin did not disrupt lysosomal membranes. The uptake of LY was not affected by T-2 toxin, which indicated that T-2 toxin did not interfere with the endocytic pathway. Results indicate that T-2 toxin and its congeners do not exert their primary toxic effect through lysosomal enzymes, membranes, or via the endocytic pathway.