[Study of thermal injury effects on human HaCaT cells under simulated microgravity environment]

Objective: To investigate the thermal injury effects on human HaCaT cells under simulated microgravity environment. Methods: The human HaCaT cells were collected and divided into simulated microgravity thermal injury (SMGTI) group, normal gravity thermal injury (NGTI) group, and normal gravity false injury (NGFI) group according to the random number table. Cells in NGTI and NGFI groups were cultured routinely in culture bottle, and cells in SMGTI group were cultured in the rotary cell culture system to simulate microgravity environment. Cells in SMGTI and NGTI groups were bathed in hot water of 45 ℃ for 10 minutes to make thermal injury model, and cells in NGFI group were bathed in warm water of 37 ℃ for 10 minutes to simulate thermal injury. At post injury hour (PIH) 12, cell morphology of 3 groups was observed under inverted phase contrast electron microscope. At PIH 2, 6, and 12, single cell suspension in the 3 groups was collected to detect the cell cycle by flow cytometer and the mRNA expressions of heat shock protein 70 (HSP70), matrix metalloproteinase 9 (MMP-9), and cysteine-aspartic protease 3 (caspase-3) by real time fluorescence quantitative reverse transcription polymerase chain reaction, and the experiments were repeated for 3 times. At PIH 2, 6, and 12, cell culture supernatant in the 3 groups was collected to detect the concentration of heparin-binding epidermal growth factor (HB-EGF) by enzyme linked immunosorbent assay method, the experiment was repeated for 3 times. The sample in each group and each time point was 3. Data were statistically analyzed with analysis of variance for factorial design, one-way analysis of variance, least significant difference test, Kruskal-Wallis H test, and Mann-Whitney U test. Results: (1) At PIH 12, cells in NGFI group showed regular shape and regular arrangement, with no cell debris. The cell shape in NGTI group was generally regular, with fewer cell debris and closer arrangement than that in NGFI group. The cells in SMGTI group showed more irregular shapes, different sizes, and dead cell debris. (2) The percentage of G1 phase cells in NGTI group was significantly higher than that in NGFI group and SMGTI group at PIH 2, respectively (P<0.05), and the percentage of G1 phase cells in NGTI group was significantly lower than that in NGFI group and SMGTI group at PIH 6 and 12, respectively (P<0.05). The percentage of G2/M phase cells in NGTI group was significantly lower than that in SMGTI group at PIH 2 (P<0.05), and the percentage of G2/M phase cells in NGTI group was significantly higher than that in NGFI group and SMGTI group at PIH 6 and 12, respectively (P<0.05). The percentage of S phase cells in NGTI group at PIH 2, 6, and 12 was significantly higher than that in SMGTI group (P<0.05), and the percentage of S phase cells in NGTI group at PIH 2 and 6 was significantly lower than that in NGFI group (P<0.05). (3) The HSP70 mRNA expressions of cells in NGTI group were 2.50±0.30 and 3.99±0.35 at PIH 2 and 6, which were significantly higher than 1.14±0.15 and 0.82±0.27 in NGFI group (P<0.05), and 1.17±0.53 and 1.65±0.59 in SMGTI group (P<0.05). The MMP-9 mRNA expression of cells in SMGTI group was significantly higher than that in NGTI group at PIH 2, 6, and 12, respectively (Z=-2.319, -2.882, -2.908, P<0.05). At each time point after injury, the mRNA expression of caspase-3 of cells in NGTI group was similar to that in NGFI group and SMGTI group, respectively (P>0.05). (4) The concentration of HB-EGF in cell culture supernatant of NGTI group was significantly lower than that in NGFI group at PIH 2, 6 and 12 (P<0.05), and the concentration of HB-EGF in cell culture supernatant of SMGTI group was significantly higher than that in NGTI group at PIH 2 and 6 (P<0.05). Conclusions: The proliferation and secretion functions and expression of wound repair related protein of human HaCaT cells inflicted with thermal injury in simulated microgravity environment showed complex and diversified changes, which provide theoretical basis for further research on damage repair under weightlessness.

Edi-3, a new independent prognostic factor in ovarian cancer

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Background: Recently, we have identified for the first time a new putative phosphodiesterase named edi-3 that correlates with tumorigenesis in endometrial cancer. In the present study we analyzed the prognostic relevance of edi-3 in ovarian cancer. Methods: Edi-3 mRNA expression was measured by quantitative RT-PCR (TaqMan) in 62 patients with primary ovarian cancer. All patients signed informed consent, approved by the Clinical Review Board and Ethics Committee of the Medical University Berlin, Charité, Germany. The tumor specimens were collected according to the Tumor Bank Ovarian Cancer standard operating procedures. A validated systematic intraoperative documentation tool was used for the detailed documentation of all surgical procedures. Using the multivariate proportional hazard model we analyzed whether edi-3 predicts survival independent from FIGO-stage, grading, postoperative residual disease and histological type. Results: Edi-3 expression is associated with survival in the univariate Cox model (hazards ratio [HR]: 1.488, 95% confidence interval [CI]: 1.131 - 1.959, P=0.005). Interestingly, edi-3 was also predictive in the multivariate proportional hazard model adjusted for the conventional clinical factors (HR: 1.521, CI: 1.107 - 2.090, P=0.010). Conclusions: Edi-3 is a new independent prognostic factor in primary ovarian cancer with HR=1.5 (P=0.010). Its function, a possible role in inositol phosphate metabolism, will be further explored in a multi-instutional setting.

No significant financial relationships to disclose.

Overexpression of the plasminogen activator inhibitor type-1 in epithelial ovarian cancer

BACKGROUND

The plasminogen activator-plasmin cascade plays a central role in the progression of solid tumors. The type-1 plasminogen activator inhibitor (PAI-1) is the major physiological regulator of plasminogen activation. PAI-1 is suggested to play a crucial role in tumor cell invasion and metastasis of various solid tumors. The aim of this study was to analyze the clinical and prognostic roles of PAI-1 in epithelial ovarian cancer (OC).

MATERIALS AND METHODS

Expression analysis was conducted by immunohistochemistry and ELISA. Tissue sections of paraffin-embedded tumor specimens and fresh-frozen tumor samples from patients with benign and malignant ovarian tumors (OT), who had undergone surgical intervention in the Department of Gynaecology and Obstetrics, Charité, Germany, from 02/01 to 06/02, were used. Correlation analysis with conventional clinical factors, univariate and multivariate analyses were performed using SPSS (SPSS Inc., V.11.0).

RESULTS

Sixty-five patients (31 primary OC, 20 recurrent OC, 4 low-malignant potential OT, 6 benign OT, 4 normal ovary) were allocated to this trial. The median age was 57 years (range, 34-86) and the median follow-up was 20 months (range, 0-64). The distributions of (FIGO) tumor stage of all primary OC were: I = 16.1%, II = 3.2%, III = 45.2% and IV = 35.5%. PAI-1 was significantly overexpressed in the tumor epithelium of OC in comparison to the ovarian epithelium of benign OT and normal ovary (p < 0.001). The median PAI-1 level was 1.92-fold higher in malignant OT than in benign OT. Statistical analyses showed no significant correlation between the expression of PAI-1 and clinical parameters. The expression of PAI-1 and the PAI-1 level, according to 3 different cut-off values, showed no prognostic impact in univariate analysis. In multivariate analysis, only tumor stage (FIGO) (p = 0.003) and residual tumor (p = 0.009) remained independent prognostic factors for post-operative survival.

CONCLUSION

PAI-1 is significantly overexpressed in OC.

Genome of the bacterium Streptococcus pneumoniae strain R6

Streptococcus pneumoniae is among the most significant causes of bacterial disease in humans. Here we report the 2,038,615-bp genomic sequence of the gram-positive bacterium S. pneumoniae R6. Because the R6 strain is avirulent and, more importantly, because it is readily transformed with DNA from homologous species and many heterologous species, it is the principal platform for investigation of the biology of this important pathogen. It is also used as a primary vehicle for genomics-based development of antibiotics for gram-positive bacteria. In our analysis of the genome, we identified a large number of new uncharacterized genes predicted to encode proteins that either reside on the surface of the cell or are secreted. Among those proteins there may be new targets for vaccine and antibiotic development.

Sickle cell disease in pregnancy: twenty years of experience at Grady Memorial Hospital, Atlanta, Georgia

OBJECTIVE

We compared pregnancy outcomes among women with sickle cell disease with outcomes for African American women without the disease.

STUDY DESIGN

We selected 127 deliveries in women with sickle cell disease (hemoglobin SS or hemoglobin SC) that occurred between 1980 and 1999. A control group of 129 deliveries by African American women with normal hemoglobin (hemoglobin AA) was also selected. Evaluated pregnancy outcomes included low birth weight, prematurity, intrauterine growth restriction, antepartum hospital admission, preterm labor or preterm premature rupture of membranes, postpartum infection, preeclampsia, pyelonephritis, intrauterine fetal death, perinatal mortality, and maternal mortality.

RESULTS

Compared with deliveries among women with hemoglobin AA, deliveries among women with hemoglobin SS or hemoglobin SC were at increased risk for intrauterine growth restriction, antepartum hospital admission, and postpartum infection. In addition, deliveries among women with Hb SS were more likely to be complicated by low birth weight, prematurity, and preterm labor or preterm premature rupture of membranes when compared with deliveries among women with hemoglobin AA. There were no significant differences among the groups (hemoglobin SS, hemoglobin SC, and hemoglobin AA) in terms of perinatal deaths; there were no maternal deaths in the study population.

CONCLUSION

Those caring for women with sickle cell disease should be aware that they are at increased risk for pregnancy complications, although overall pregnancy outcome is favorable.

Biochemical characterization of signal peptidase I from gram-positive Streptococcus pneumoniae

Bacterial signal peptidase I is responsible for proteolytic processing of the precursors of secreted proteins. The enzymes from gram-negative and -positive bacteria are different in structure and specificity. In this study, we have cloned, expressed, and purified the signal peptidase I of gram-positive Streptococcus pneumoniae. The precursor of streptokinase, an extracellular protein produced in pathogenic streptococci, was identified as a substrate of S. pneumoniae signal peptidase I. Phospholipids were found to stimulate the enzymatic activity. Mutagenetic analysis demonstrated that residues serine 38 and lysine 76 of S. pneumoniae signal peptidase I are critical for enzyme activity and involved in the active site to form a serine-lysine catalytic dyad, which is similar to LexA-like proteases and Escherichia coli signal peptidase I. Similar to LexA-like proteases, S. pneumoniae signal peptidase I catalyzes an intermolecular self-cleavage in vitro, and an internal cleavage site has been identified between glycine 36 and histidine 37. Sequence analysis revealed that the signal peptidase I and LexA-like proteases show sequence homology around the active sites and some common properties around the self-cleavage sites. All these data suggest that signal peptidase I and LexA-like proteases are closely related and belong to a novel class of serine proteases.

Antihelicase action of CI-958, a new drug for prostate cancer

CI-958, a new DNA-intercalating drug derived from a series of substituted 2H-[1] benzothiopyrano[4,3,2-cd]indazoles, is being tested in clinical trails because of its curative properties against murine solid tumor models and because it has demonstrated activity in a pilot phase II study of patients with hormone-refractory prostate cancer. However, the mechanism of anticancer action of CI-958 has not been established. Because CI-958 binds to DNA and DNA helicases are profoundly affected by DNA-binding drugs, we examined the effects of CI-958 on human DNA helicase action. DNA helicase activity was measured by strand dissociation of double-stranded (ds) DNA with a gel electrophoresis assay, and ATPase activities were determined on thin-layer chromatography by measurement of the conversion of ATP to ADP. For human helicase blockade, CI-958 is slightly more potent than doxorubicin (EC50 values 0.17 and 0.26 microM, respectively). We observed no difference in helicase-blockade EC50 values recorded for three helicase substrates containing A-T rich, G-C rich, and both types of oligonucleotide sequences. The effects of CI-958 helicase blockade and DNA-dependent ATPase activities were similar for the two reactions. The kinetics of the blockade by CI-958 of the human DNA helicase indicates that it involves a reversible ternary complex of helicase-drug-dsDNA. CI-958 produces potent blockade of human DNA helicases with no apparent strong DNA sequence-binding preference. Similar potency against helicase strand dissociation and DNA-dependent ATPase suggests that the mechanism against these reactions is the same. The blockade of DNA helicases by CI-958 may be central in its mechanism of action as an anticancer drug.

Anthracycline antibiotic blockade of SV40 T antigen helicase action

We previously showed that anthracycline antibiotics potently block SV40 large T antigen helicase; in the present study, we describe the kinetics and the structure-activity characteristics of this process. The concentration vs effect data for helicase blockade were fitted by the Hill equation to yield nearly parallel log-concentration effect curves for a series of active anthracycline antibiotics. The effective concentration for 50% helicase blockade (EC50) values ranged from 0.34 microM for daunorubicin to 40.8 microM for 3'-deaminodaunorubicin. Clinically inactive 3'-N-acyl anthracyclines produced no blockade. The Hill constants for the blockade ranged from 1.1 to 1.6 for the entire series of active anthracyclines, indicating no positive cooperativity and suggesting that a single molecule of bound drug is sufficient to block helicase action. The EC50 values for several clinically effective anthracyclines showed a relationship to the average DNA binding constants for these drugs, and Lineweaver-Burk analysis of the blockade kinetics indicated non-competitive inhibition. The kinetics of the blockade indicated that the anthracycline, DNA, and helicase form a ternary complex that is irreversible under the reaction conditions. This mechanism may be central to the cytotoxic and anti-cancer activities of anthracycline antibiotics and may be useful in understanding the enzymatic mechanism of DNA helicase action.

Madelung disease: distribution of cervical fat and preoperative findings at sonography, MR, and CT

PURPOSE

Our goal was to document the distribution of excess fat in the neck and to determine the preoperative role of sonography, CT, and MR imaging in patients with Madelung disease.

METHODS

Eight patients with Madelung disease were examined preoperatively with sonography, CT, and MR imaging of the neck, and the extent to which each technique provided answers to the surgeons' questions--such as distribution of fat, course of the major vessels within the fat, and presence of tracheal compression and nonlipomatous lesions--was studied.

RESULTS

Excess fat was seen predominantly in the posterior part of the neck (eight patients), under the trapezius (eight patients) and sternomastoid (six patients) muscles, in the supraclavicular fossa (five patients), between the paraspinal muscles (five patients), in the anterior part of the neck (suprahyoid in seven patients and infrahyoid in three patients), in the superior mediastinum (three patients), and in the prevertebral space (two patients). Excess fat deposition was also seen in the pretracheal space (one patient), extrapleural space (two patients), and over the cheeks (one patient), sites previously not described.

CONCLUSION

As a preoperative investigative tool for Madelung disease, both MR imaging and noncontrast CT provide the surgeon with adequate information; sonography is less helpful.