Suppression of nitric oxide-induced apoptosis by N-acetyl-L-cysteine through modulation of glutathione, bcl-2, and bax protein levels

It has been demonstrated that nitric oxide (NO) can promote apoptosis in human cancer cells. To test the protective effects of antioxidants (N-acetyl-L-cysteine (LNAC) and free-radical spin traps (5,5-dimethyl-1-pyrroline N-oxide and 2,2,6,6,-tetramethyl-1-piperidinyloxy) against NO-induced apoptosis, a human colon cancer cell line (COLO 205) was treated with NO, and its survival rate was evaluated both with and without antioxidant therapy. LNAC arrested the development of progression of apoptosis in COLO 205 cells in a dose-dependent manner, promoted long-term survival, and prevented the internucleosomal DNA cleavage induced by NO. The intracellular level of glutathione (GSH) was found to be elevated in cells after exposure to LNAC. The bax protein levels were elevated by NO treatment, and this effect was blocked by LNAC. On the other hand, the bcl-2 oncoprotein level in the LNAC-pretreated cells was significantly elevated in a time-dependent manner compared to cells that received NO pretreatment. In summary, our results suggest that the protective effect of LNAC may be linked to its inducement of increases in cellular GSH and bcl-2 protein levels and to its suppression of cellular bax protein in treated cells.

Overexpression of cellular glutathione peroxidase does not affect expression of plasma glutathione peroxidase or phospholipid hydroperoxide glutathione peroxidase in mice offered diets adequate or deficient in selenium

Selenium-dependent cellular glutathione peroxidase (GPX1) overexpressing [GPX1(+)] mice were derived by microinjecting a 5.3-kb cloned entire mouse GPX1 genomic DNA into fertilized eggs. The objective of this study was to determine the effect of GPX1 overexpression and dietary selenium on the expression of selenoperoxidases and the status of lipid peroxidation of these transgenic animals. An experiment with a 2 x 2 factorial arrangement of treatments with 15 GPX1(+) and 15 control mice (2 mo old) was conducted for 8 wk. Ten mice of each group (half males and females) were fed a Se-deficient, Torula yeast basal diet (0.02 mg Se/kg, no supplemental vitamin E) and five mice (three males and two females) were fed the basal diet supplemented with 0.51 mg Se/kg as Na2SeO3. The GPX1(+) mice had greater GPX1 activities (one- to sixfold, P < 0.0001) than the control mice at both levels of dietary selenium in all tissues except for liver, in which such difference (100%, P < 0.05) was observed only in Se-deficient mice. The GPX1 mRNA level in kidney and in lung of the Se-deficient GPX1(+) mice was 81% and 7.5-fold greater (P < 0.003) than the respective control level. Overexpression of GPX1 did not alter phospholipid hydroperoxide glutathione peroxidase (GPX4) activities and mRNA levels or glutathione S-transferase (GST) activities in most of the tissues, plasma glutathione peroxidase (GPX3) activity or plasma Se concentrations. No differences in lipid peroxidation in kidney, lung or intestine were observed between the Se-deficient GPX1(+) and control mice. In conclusion, the overexpression of the GPX1 gene in these mice was tissue specific and did not affect the expression of GPX3, GPX4 or GST and plasma Se levels; dietary Se appeared to affect the GPX1 overexpression at its mRNA level.

The Gpx1 gene encodes mitochondrial glutathione peroxidase in the mouse liver

Mitochondria have GPX and PHGPX activity. It has been an unsettled issue whether mitochondrial GPX is encoded by Gpx1. Unlike the Gpx4 gene which encodes PHGPX with alternative transcription and translation start sites determining the subcellular localization of PHGPX, the Gpx1 gene appears to have a single translation start site. Additionally, mitochondrial GPX has been shown to have different chromatographic and kinetic properties from the cytosolic GPX1. We studied mouse liver mitochondrial GPX activity in homozygous Gpx1-knockout mice. Mitochondria were enriched at the density of 1.10 g/ml in the Percoll gradients as shown by electron microscopy. The H2O2-reducing GPX activity in the highly enriched mitochondrial fraction of wild-type mouse liver is 2700 mU/mg which is about one-half of specific activity found in cytosol. There is less than 0.5% GPX activity in the cytosol and no GPX activity in the mitochondria of Gpx1-knockout mouse liver compared to the cytosol of wild-type mouse liver using H2O2 or cumene hydroperoxide as the substrate. The fact that the knockout mice express normal levels of plasma GPX as well as testis and liver PHGPX activity indicates that animals are not selenium-deficient. Based on these observations, we concluded that mitochondrial GPX is the product of the Gpx1 gene.

Skull metastasis with brain invasion from thyroid papillary microcarcinoma

Thyroid papillary microcarcinoma has a notably benign clinical course among carcinomas. The occurrence of distant metastases is exceptional, but significantly increases the risk of mortality. We report the case of a 75-year-old woman with a 1.0 cm primary thyroid papillary microcarcinoma with skull metastases and brain invasion. The clinical presentation was a large mass over the occipital area which progressively grew over the course of 1 year. No thyroid nodule or lymph nodes were palpable. The metastatic mass and primary tumor were surgically removed. The serum thyroglobulin level was 163 ng/mL 1 month after surgery. There was no further management because the patient refused follow-up. She returned to the hospital 15 months later due to a seizure. The tumor had further extended into the brain tissue. Her condition progressively deteriorated and she died 2 months later due to uncontrollable seizures.

The contribution of GSH peroxidase-1, catalase and GSH to the degradation of H2O2 by the mouse lens

Utilizing cultured lenses from normal and homozygous glutathione peroxidase (GSHPx-1) knockout mice and inhibitors for GSSG Reductase (GSSG Red), 1,3-bis(2-chlorethyl)-1-nitrosourea (BCNU) and catalase (Cat), 3-aminotriazole (3-AT), the ability to degrade H2O2 was examined at two H2O2 concentrations, 300 microM and 80 microM. It was found that GSHPx-1 contributed about 15% to the H2O2 degradation. The Cat contribution was concentration dependent being about 30% at 300 microM H2O2 and approximately 8% to 15% at 80 microM H2O2. GSH loss measured as nonprotein thiol (NP-SH) was shown to be linked to most of the remaining H2O2 degradation accounting for about 54% to 72% of the H2O2 degradation at 300 microM and 80 microM, respectively. However, based on evaluation of the ability of GSH to nonenzymatically degrade H2O2, it can only account for about 36% at 300 microM and 19% at 80 microM H2O2 of the observed lens H2O2 degradation. It is, therefore, concluded that lens GSH must be involved in other reactions either directly or indirectly related to H2O2 degradation.

Immunohistochemical analysis of insulin-like growth factor I, insulin-like growth factor I receptor and insulin-like growth factor II in endometriotic tissue and endometrium

BACKGROUND

The purpose of this study was to investigate unprecedentedly immunohistochemical localization of insulin-like growth factor I, insulin-like growth factor I receptor and insulin-like growth factor II in endometriotic tissue, and to compare staining intensity with that of endometrium obtained simultaneously.

METHODS

Endometriotic and corresponding endometrial tissue samples were obtained during operative laparoscopy from eighteen infertile patients for the problem of infertility. Semiquantitative scoring was used for analysis of results.

RESULTS

It was demonstrated that insulin-like growth factor I and insulin-like growth factor I receptor were present in both endometriotic and endometrial tissues. In contrast, there was little insulin-like growth factor II present in either ectopic or eutopic endometrial tissue. For insulin-like growth factor I and insulin-like growth factor I receptor, the immunostaining score was similar between ectopic and eutopic endometrial tissues. There was no significant difference in immunostaining score between glandular epithelium and stromal cells.

CONCLUSIONS

insulin-like growth factor I and insulin-like growth factor I receptor could be demonstrated immunohistochemically in both endometriotic and endometrial tissues.

Brain acetylhydrolase that inactivates platelet-activating factor is a G-protein-like trimer

The platelet-activating factor PAF (1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) is a potent lipid first messenger active in general cell activation, fertilization, inflammatory and allergic reactions, asthma, HIV pathogenesis, carcinogenesis, and apoptosis. There is substantial evidence that PAF is involved in intracellular signalling, but the pathways are poorly understood. Inactivation of PAF is carried out by specific intra- and extracellular acetylhydrolases (PAF-AHs), a subfamily of phospholipases A2 that remove the sn-2 acetyl group. Mammalian brain contains at least three intracellular isoforms, of which PAF-AH(Ib) is the best characterized. This isoform contains a heterodimer of two homologous catalytic subunits alpha1 and alpha2, each of relative molecular mass 26K, and a non-catalytic 45K beta-subunit, a homologue of the beta-subunit of trimeric G proteins. We now report the crystal structure of the bovine alpha1 subunit of PAF-AH(Ib) at 1.7 A resolution in complex with a reaction product, acetate. The tertiary fold of this protein is closely reminiscent of that found in p21(ras) and other GTPases. The active site is made up of a trypsin-like triad of Ser 47, His 195 and Asp 192. Thus, the intact PAF-AH(Ib) molecule is an unusual G-protein-like (alpha1/alpha2)beta trimer.

Peroxide-induced damage in lenses of transgenic mice with deficient and elevated levels of glutathione peroxidase

Transgenic mice with elevated glutathione peroxidase (GSHPx) activity and gene knockout animals with a deficiency of the enzyme were used to investigate the role of GSHPx in defending the lens against H2O2-induced damage. The effects of peroxide on cultured lenses were determined by using light and transmission electron microscopy to evaluate morphological changes occurring in the epithelium and superficial cortex of the central and equatorial regions of the lens. DNA single-strand breaks in the epithelium were also examined. Following a 30-min exposure to 25 microM H2O2, lenses from normal animals showed distinct changes in the morphology of both the epithelium and superficial cortex. The damage to these cells was extensive in lenses of gene knockout mice in which activity of GSHPx was undetectable. In marked contrast, lenses of transgenic mice, which had 5-fold higher activities of GSHPx, were able to resist the cytotoxic effects. Similar to damage to cell morphology, the extent of DNA strand breaks was significantly lower (40% of control) in H2O2-exposed lenses as compared to normal lenses while DNA damage in gene knockout lenses was 5 times greater than that of GSHPx-rich transgenic lenses. The present studies extend our previous findings on the role of the glutathione redox cycle in the detoxification of peroxide and demonstrate that an increase in GSHPx activity protects the lens against peroxide-induced changes in cell morphology and DNA strand breaks.

Effects of hypoxia on expression of superoxide dismutases in cultured ATII cells and lung fibroblasts

This study investigated whether hypoxia affected the expression of mitochondrial manganese-containing superoxide dismutase (Mn-SOD) and the cytosolic copper and zinc-containing superoxide dismutase (Cu,Zn-SOD) in alveolar type II epithelial (ATII) cells and lung fibroblasts. Cells were exposed in vitro to air (controls) or to 2.5% oxygen (hypoxia) for 24 h. Mn-SOD and Cu,Zn-SOD mRNA expression was measured by quantitative reverse transcriptase-polymerase chain reaction. Both Mn-SOD and Cu,Zn-SOD mRNA expression in ATII cells decreased significantly after 1 day in hypoxic conditions. The decrease in Mn-SOD mRNA (-69%) was greater than that in Cu,Zn-SOD mRNA (-48%). ATII cell surfactant protein A transcript expression remained constant. Mn-SOD (-52%) and Cu,Zn-SOD (-54%) mRNA expression decreased similarly in lung fibroblasts cultured during hypoxia. The half-life of the Mn-SOD mRNA measured in lung fibroblasts exposed to air or hypoxia for 24 h decreased significantly from 5.8 +/- 0.1 to 3.8 +/- 0.7 h (-34%). The half-life for the Cu,Zn-SOD decreased significantly from 4.0 +/- 0.3 to 2.4 +/- 0.1 h (-40%). Neither Mn-SOD nor Cu,Zn-SOD protein expression in ATII cells changed significantly during hypoxia. Hypoxia decreases expression of Mn-SOD and Cu,Zn-SOD mRNA in ATII cells and lung fibroblasts in part by decreasing stability of the mRNA transcripts.

Nasopharyngeal Castleman's disease

A 19-year-old male was admitted to our clinic because of nasal obstruction and intermittent postnasal drip of 3 to 4 years' duration. Physical examination revealed a wide-based, smooth-surfaced nasopharyngeal tumor which was suspected to be a nasopharyngeal angiofibroma after examination of computed tomographic scans and an angiogram. However, after the tumor was removed by surgical excision via a transpalatal approach, the pathologic examination revealed Castleman's disease of the hyaline-vascular type. There was neither evidence of recurrence nor nasal problems at 4 years' follow-up. To our knowledge, Castleman's disease, or angiofollicular lymph node hyperplasia, may present as a local or generalized tumor-like condition, usually in the chest or abdomen, and may involve both the lymph nodes and non-nodal tissues. A review of previous articles reveals that there has not been any report of Castleman's disease found in the nasopharynx. This rare disorder is presented and discussed.

Establishment of xenografts and cell lines from well-differentiated human thyroid carcinoma

BACKGROUND

Our aim was to establish Chinese human thyroid cancer cell lines and to provide the material for thyroid cancer research.

METHODS

We collected thyroid cancer tissues from 93 patients with thyroid cancer for developing the primary culture. Thyroid cancer tissues were verified by frozen sections during the operations, then subjected to primary cell culture. During the first several passages, fibroblasts were removed by selective attachment.

RESULTS

From the 93 cancer tissues used, two follicular cancer tissues from the metastatic area (CGTH W-1, CGTH W-2) and one papillary thyroid cancer tissue (CGTH W-3) could be passed over 50 times. Cellular transformation with loss of contact inhibition occurred during passages 5-8. Electron microscopic studies of the CGTH W-1 cell line showed the presence of an abundance of mitochondria and Golgi complex. Presence of microvilli with interdigitations between neighboring cells were found in CGTH W-2 and CGTH W-3 cell lines. Severe combined immunodeficient (SCID) mice were used to determine whether these cells were tumorigenic. Two months after transplantation of 1 x 10(7) CGTH W-1, 2, and 3 cells into SCID mice, subcutaneous tumors approximately 2-2.5 cm in size were clearly visible. After affinity cross-linking an IGF-I with insulin-like growth factor binding proteins complex corresponding to a molecular size of 41 kDa was observed in culture media collected from CGTH W-1, SW 579, and RO82 W-1 cells.

CONCLUSIONS

Three thyroid cancer cell lines were established, which may provide material for future thyroid cancer research.

Clinical presentations and treatment for 74 occult thyroid carcinoma. Comparison with nonoccult thyroid carcinoma in Taiwan

There is limited clinical information of Chinese patients with occult well-differentiated thyroid cancer (OTC). The purposes of this study were to elucidate the clinical presentations and results of treatment in the patients with OTC in Taiwan. The data of 568 patients with pathologically verified papillary and follicular thyroid carcinomas who received primary treatment in Chang Gung Memorial Hospital were retrospectively reviewed. Seventy-four of 568 patients with well-differentiated thyroid carcinoma were OTC; those included 71 papillary thyroid carcinomas and three follicular carcinomas. Among the 74 OTC patients, five cases (6.8%) presented with distant metastases, but 41 cases (10.1%) were found with distant metastases in 416 nonoccult thyroid cancer (NOTC) (p = 0.509). In the five OTC with distant metastases, there were three papillary carcinomas and two follicular carcinomas. Only one case (1.4%) died of distant metastasis of the occult papillary thyroid carcinoma versus 20 cases out of the total 568 (4.1%) well-differentiated thyroid carcinomas. After statistical analysis, there were no differences between the survival rates of OTC and NOTC patients. In the present study, 1 month postoperative serum thyroglobulin level could be used as prognostic factor in both OTC and NOTC patients. Only 54.17% of OTC patients were diagnosed as thyroid cancer by thyroid ultrasonography with the fine needle aspiration cytology. In conclusion, most OTC had relatively benign clinical courses, but distant metastases may result in mortality still observed. Therefore, OTC should be treated as NOTC, since relatively high rate of distant metastases were found in the patients with OTC.

Serial MRI studies in pathologically verified Balò's concentric sclerosis

We report serial MRI studies in a patient with Balò's concentric sclerosis, who presented with a progressive weakness in the right limbs of 10 day duration. Serial MR images revealed several concentric lesions characterized by layer by layer of demyelinated and myelinated appearance and multiple plaques in the white matter. Pathological study of a biopsy of a concentric lesion (which was performed to rule out neoplasm) further confirmed this diagnosis. These MR findings resolved in correspondence with clinical improvement. The patient was almost completely normal 1 year later. In conclusion, in this case, we found that MRI could show the striking feature reminiscent of the histopathologic findings of Balò's concentric sclerosis and played an important role in antemortem diagnosis of this rare demyelinating disease.

The protective role of manganese superoxide dismutase against adriamycin-induced acute cardiac toxicity in transgenic mice

Adriamycin (ADR) is a potent anticancer drug known to cause severe cardiac toxicity. Although ADR generates free radicals, the role of free radicals in the development of cardiac toxicity and the intracellular target for ADR-induced cardiac toxicity are still not well understood. We produced three transgenic mice lines expressing increased levels of human manganese superoxide dismutase (MnSOD), a mitochondrial enzyme, as an animal model to investigate the role of ADR-mediated free radical generation in mitochondria. The human MnSOD was expressed, functionally active, and properly transported into mitochondria in the heart of transgenic mice. The levels of copper-zinc SOD, catalase, and glutathione peroxidase did not change in the transgenic mice. Electron microscopy revealed dose-dependent ultrastructural alterations with marked mitochondrial damage in nontransgenic mice treated with ADR, but not in the transgenic littermates. Biochemical analysis indicated that the levels of serum creatine kinase and lactate dehydrogenase in ADR-treated mice were significantly greater in nontransgenic than their transgenic littermates expressing a high level of human MnSOD after ADR treatment. These results support a major role for free radical generation in ADR toxicity as well as suggesting mitochondria as the critical site of cardiac injury.

Transgenic mice overexpressing glutathione peroxidase are resistant to myocardial ischemia reperfusion injury

To test the authors' hypothesis that cellular antioxidant enzymes constitute a cellular defense against acute stress, myocardial ischemia reperfusion injury in transgenic mice overexpressing the cellular glutathione peroxidase (GSHPx-1) was studied. Transgenic mice were generated using the entire mouse GSHPx-1 gene including approximately 2.0 kb 5'flanking sequence. A 400% increase of GSHPx activity was found in the hearts of transgenic mice compared with non-transgenic controls. Isolated perfused hearts were prepared from two groups of mice: transgenic overexpressed; non-transgenic controls. Hearts were perfused by Langendorff mode, and after 10 min of stabilization subjected to 30 min of ischemia followed by 20 min of reperfusion. In addition, a group of hearts were perfused for 50 min without subjecting them to ischemia and reperfusion to demonstrate the stability of heart preparation. Transgenic mouse hearts demonstrated significantly improved recovery of contractile force and the rate of contraction, compared to non-transgenic control mouse hearts. The infarct size was also lower in transgenic mouse hearts compared to those of non-transgenic controls. In concert, following ischemia, release of creatine kinase from the transgenic hearts was significantly lower than the control group. The results of this study indicate that increased GSHPx-1 expression renders the heart more resistant to myocardial ischemia reperfusion injury.

p53 gene mutation in cerebral primitive neuroectodermal tumor in Taiwan

p53 mutation has been rarely reported in cerebral primitive neuroectodermal tumors (PNET). To determine the significance of p53 mutations in the development of cerebral PNET, we studied cerebral PNET samples from 14 patients, 8 females and 6 males with a mean age of 38 years (range 10 months to 77 years) who had total or subtotal surgical resection. Histological typing of PNET with neuronal (N) and non-neuronal (NN) differentiation groups revealed 8 and 6 cases, respectively. Six (43%) of the 14 patients had p53 mutation. The p53(+) and p53(-) groups had an age range of 19-77 with a mean of 49 years and 10 months to 57 years with a mean of 30 years, respectively. p53 expression between the PNET-N and PNET-NN groups was 5 of 8 (62.5%) and 1 of 6 (16.7%), respectively. The mutations contained 3 transitions, 2 transversions and 1 frameshift; none of them occurred at the site of 'hot-spot' residues (codons 175, 248, 273). The results suggest that: (1) p53 mutation in cerebral PNET tends to show a higher incidence of neuronal differentiation and occurs in the older age group in Taiwan, (2) there was no difference in survival time between the PNET-N and PNET-NN groups (7 months and 6 months) (P = 0.54), and between p53(+) and p53(-) groups (6 months and 7 months) (P = 0.57), and (3) PNET may be an entity of a heterogenous group of tumors with different genetic mechanisms controlling their trends of differential lineage. Further studies are needed to determine the significance of p53 mutations in PNET development, especially the role of carcinogens in the genesis of PNET in Taiwan.

Effect of selenium on 1,2-dimethylhydrazine-induced intestinal cancer in rats

PURPOSE

This study was designed to determine the cancer prevention and therapeutic effects of selenium on rats treated with 1,2-dimethylhydrazine (DMH).

METHODS

One hundred sixty Spraque-Dawley male rats were divided into seven groups and received 20 mg/kg/week DMH, subcutaneously for 20 weeks. Two different dosages of selenium (8 and 4 ppm) were administered to the rats through drinking water during DMH treatment (B and C groups) or one month before and during DMH treatment (D and E groups). The rats of Groups A (control group), B, C, D, and E were killed immediately after the last DMH injection. The incidence of intestinal cancer in each group was compared. Eight ppm selenium was also administered to rats after DMH treatment (Group F), and survival times were observed and compared with Group G (treated with DMH only).

RESULTS

Rats of Groups B and D received 8 ppm selenium and had a significantly decreased incidence of intestinal cancer (from 65.8 percent (Group A) to 33.3 percent (Group B) and 27.8 percent (Group D); P = 0.0225 and 0.0038). Rats receiving 4 ppm selenium had a relatively decreased incidence of intestinal cancer (from 65.8 percent (Group A) to 44.4 percent (Group C) and 47.1 percent (Group E) but P > 0.05). Survival time of Groups F and G showed no difference.

CONCLUSIONS

Eight ppm selenium provided via drinking water has a significant intestinal cancer prevention effect in the presence of a high dose of DMH (20 mg/kg x 20 weeks), and the cancer therapeutic effect of selenium is doubtful in this animal model.

p53 gene mutation in thyroid carcinoma

The pattern of p53 protein expression was examined in 92 cases of thyroid carcinoma. When the cases were divided into two groups with regard to their cytoplasmic staining only or nucleus staining only, the frequency of the nucleus staining group was significantly higher in the poorly differentiated carcinoma (PDC) and undifferentiated carcinoma (UDC) groups (10.5% and 25%) compared with the other groups of histologic subtype (0%). The results suggest positivity in nucleus staining for p53 may be a marker for the biologically worse carcinomas, PDC and UDC, however, tumors showing only cytoplasmic staining of p53 favor a fair prognosis. In this paper, we also elucidate the spectrum of genotypic aberrations of p53 in each histological subtype. Of 92 thyroid tumor samples analyzed, the overall frequency of p53 mutation was 8.5%. The mutations occurred in 4.35% (2/46) ot WDC, 17.2% (5/29) of PDC, and 16.7% (1/6) of oncocytic carcinoma. Two of five PDC cases and one papillary carcinoma revealed point mutations in exon 8 as follows; GTG (val) to CTG (leu) at codon 272 in case 23T, CGA (arg) to CCA (pro) at codon 306 in case of 30T, and CGG (arg) to AGG (arg) at codon 282 in case 28T. All of the p53 mutations detected were represented by single nucleotide changes including two missense and one silent mutation. In contrast to the missense mutations found in PDC, it is interesting to note that the silent mutation was checked in 28T of well differentiated papillary carcinoma. These results represents molecular evidence that p53 gene aberration associated with overexpression of the mutant form of p53 protein plays a crucial role in the biologically aggressive subtypes of thyroid carcinoma, and point mutation only was not sufficient to be a prognostic marker for the biologically aggressive malignancy of thyroid tumors. There was no p53 gene aberration found in four cases of undifferentiated carcinoma (UDC) studied. The results suggest that other unknown factors should be responsible for the aggressiveness in some UDC of thyroid carcinoma except overexpression of p53.

Antioxidant enzyme expression in rat lungs during hyperoxia

To understand the molecular mechanisms that upregulate the activities of pulmonary antioxidant enzymes in adult rats during exposure to 85% oxygen, the relative contents of corresponding mRNA in normal and hyperoxic lungs were determined. Hyperoxic exposure drastically induced the expression of lung manganese-containing superoxide dismutase (MnSOD) mRNA. Maximal induction of MnSOD mRNA occurred at days 3 and 5 of exposure to hyperoxia, reaching a 600 and a 340% increase over the levels of air-exposed rats, respectively. In addition, hyperoxia induced lung mRNA for glucose-6-phosphate dehydrogenase, glutathione peroxidase, glyceraldehyde-3-phosphate dehydrogenase, alpha-tubulin, and gamma-actin to different extends at various days of exposure. Hyperoxia had little or no effect on the levels of mRNA for copper/zinc-containing superoxide dismutase (CuZnSOD), catalase, heat shock protein (HSP70), and creatine kinase. Nuclear run-on experiments showed that the transcriptional rate of the MnSOD gene is enhanced in hyperoxic rat lungs by approximately 400% at day 3 of exposure compared with that of controls. The specific activities of CuZnSOD and MnSOD in these lung samples per unit of lung protein or DNA were also determined. The activity of CuZnSOD in hyperoxic lungs was found to be unchanged compared with controls, except a 20% decrease at day 7 of exposure when standardized against protein content of lung homogenate. Changes of CuZnSOD activity were more dramatic in hyperoxic lungs (a 40% increase at days 3, 5, 7, and 14 of exposure) when enzyme activity was normalized using lung DNA content. Surprisingly, no proportional increase of lung MnSOD enzyme activity was observed at days 3 and 5 of oxygen exposure. The increase of MnSOD activity per unit of lung protein also did not parallel the increase in MnSOD protein content at days 5, 7, and 14 of exposure. These data suggest that, in addition to transcriptional activation, translational and/or posttranslational regulation of the MnSOD gene expression may play a critical role in controlling lung MnSOD activity on hyperoxic exposure.

Primary cardiac chondrosarcoma

A case of primary cardiac chondrosarcoma in a 41-year-old woman who presented with cardiac tamponade and cardiac intracavitary obstruction is described. The tumor originated from the right atrium and invaded the adjacent right ventricular wall and interatrial septum. Primary cardiac chondrosarcoma is extremely rare, and its clinical, computed tomographic, echocardiographic, and magnetic resonance imaging findings are described.

Induction of p53 and p21/WAF1/CIP1 expression by nitric oxide and their association with apoptosis in human cancer cells

In this study, human and rat cancer cells were used to investigate the expression of p53 and p21/WAF1/CIP1 and their association with apoptosis after exposure to nitric oxide (NO). It was found that NO induced nuclear accumulation of p53 protein in a dose- and time-dependent manner. The level of p53 protein was elevated by about fivefold compared with that of mock-treated cells 48 h after exposure to 300 ppm NO. The induction of p53 by NO was found by pulse-chase analysis to be mainly regulated by post-translational modification. The correlation between p53 status and apoptosis induced by NO in human cancer cells was also investigated in this study. We found that apoptosis was easily induced in cells containing wild-type p53 (COLO 205 and Hep G2) after exposure to NO. The p21/WAF1/CIP1 protein was induced by NO in cells containing wild-type p53 (Hep G2) but not in cells without p53 (Hep 3B) or with mutated p53 (HT-29). Our results indicate that wild-type p53 and p21/WAF1/CIP1 expression was elevated in human cancer cells by exposure to NO and suggest that this may eventually promote apoptosis.

Variation in cellular glutathione peroxidase activity in lens epithelial cells, transgenics and knockouts does not significantly change the response to H2O2 stress

This investigation examines the contribution of glutathione peroxidase (GSHPx-1) in degrading H2O2 in lens preparations. Rabbit (N/N1003A) and normal and GSHPx-1 transfected mouse (alpha TN4-1) lens epithelial cell lines and normal and GSHPx-1 transgenic and knockout mouse lenses were utilized. GSHPx-1 activity in the cell lines was increased from two-fold to about four-fold, in the lenses from transgenics more than four-fold and the lenses from knockouts had less than 3% of normal GSHPx-1 activity. The transgenic and knockout mice as well as their lenses appeared normal for up to 3 to 4 months, the longest period of observation. The preparations were subjected to oxidative stress by placing them either in a medium containing 120 or 300 microM H2O2 or utilizing photochemical stress where the H2O2 levels normally rise to about 100 microM over a few hours in the presence of a normal lens. With all preparations, it was found that either markedly increasing or eliminating GSHPx-1 activity had only a small effect on the system's ability to metabolize H2O2, 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), an inhibitor of GSSG reductase (GSSG Red) and 3-aminotriazole (3-AT), an inhibitor of catalase, also had little effect. However, the addition of both inhibitors caused a marked decrease in H2O2 degradation. Examination of the distribution of GSHPx-1 in the lens indicated that the activity per milligram of protein was evenly distributed between the epithelium and the remainder of the lens in the normal lens and was about 1.7-fold greater in the epithelium of transgenic lenses than in the remainder of the lens. Surprisingly, the distribution of GSSG Red was quite different with eight- to ten-fold more activity in the epithelium. Catalase was also found to be concentrated in the epithelium. With H2O2 exposure, a rapid loss of non-protein thiol (NP-thiol) was found in cell cultures and in the epithelia of cultured lenses. However, the remainder of the lens showed little change in NP-thiol. The variation of GSHPx-1 activity did not influence the NP-thiol changes which occurred more rapidly and to a greater extent in the presence of BCNU. The addition of BCNU also caused a decrease in total lens NP-thiol. Examination of thymidine incorporation and choline transport, indicators of nuclear and membrane function, also reflects the H2O2 degradation data, showing little difference in the degree to which H2O2 effects these parameters in lenses from normal and transgenic animals. Catalase activity is four- to six-fold greater than GSHPX-1 activity in the alpha TN4-1 cell lines, about three-fold lower in the rabbit cell line and, remarkably, about 18-fold lower than the peroxidase in the normal mouse lens. In spite of such observations, the consistent overall conclusion is that GSHPx-1 and catalase function together but when GSHPx-1 is knocked out or GSSG Red is inhibited, catalase is able to protect the system from H2O2 stress. Indeed, the young mouse does not appear to require GSH Px-1 for normal function.

Newly established MST-1 tumour cell line and tumour-infiltrating lymphocyte culture from a patient with soft tissue melanoma (clear cell sarcoma) and their potential applications to patient immunotherapy

The establishment and characterisation of paired autologous tumour cell line (MST-1) and tumour-infiltrating lymphocyte (TIL) culture from a tumour mass of a 14-year-old Taiwanese girl with soft tissue melanoma are described. MST-1 cells grown in vitro were heterogeneous in morphology, ranging from floating round cells, loosely attached round/oval or elongated cells with prominent pseudopod-like processes, to well-attached spindle and elongated dendritic cells without obvious pseudopods. Immunostaining revealed that major melanoma-associated antigens, such as S100 protein, HMB-45, melanotransferrin, chondroitin sulphate proteoglycan, and the gangliosides GD2 and GD3, were consistently expressed by the tumour tissue, severe combined immunodeficiency (SCID) mouse xenograft and derived cell lines. Flow cytometric analysis of the tumour DNA content showed an index of 1.8 relative to normal peripheral blood lymphocyte DNA. Chromosome analysis revealed all cells at a hypotetraploid level with several clonal chromosome aberrations, including deletions at 10p and 12q, an addition at 12q, translocations t(1;14) and t(5;6). Electron microscopy showed melanosome structures. This observation and the expression of the major melanoma-associated antigens were all indicative of the melanocytic origin of MST-1 tumour. Interleukin-2 (IL-2) expanded TILs had the predominant CD8+ phenotype and the capacity to lyse cells of the cultured autologous tumour. The availability of the soft tissue melanoma cell line, the SCID mouse xenograft tumour system as well as autologous TILs described herein would provide useful materials for identifying T-cell-defined antigens as well as a model system for devising individualised cancer biotherapeutic strategies. This cell line can also be used for further studies aimed at uncovering the histogenesis of this rare cancer.