Psammaplin A, a natural bromotyrosine derivative from a sponge, possesses the antibacterial activity against methicillin-resistantStaphylococcus aureus and the DNA gyrase-inhibitory activity

Psammaplin A, a natural bromotyrosine derivative from an associated form of two sponges (Poecillastra sp. and Jaspis sp.) was found to possess the antimicrobial effect on the Gram-positive bacteria, especially on methicillin-resistant Staphylococcus aureus (MRSA). The minimal inhibitory concentration of psammaplin A against twenty one MRSAs ranged from 0.781 to 6.25 microg/ml, while that of ciprofloxacin was 0.391-3.125 microg/ml. Psammaplin A could not bind to penicillin binding protein, but inhibited the DNA synthesis and the DNA gyrase activity with the respective 50% (DNA synthesis) and 100% (DNA gyrase) inhibitory concentration 2.83 and 100 microg/ml. These results indicate that psammaplin A has a considerable antibacterial activity, although restricted to a somewhat narrow range of bacteria, probably by inhibiting DNA gyrase.     

Synthesis andin vitro antibacterial activity of quaternary ammonium cephalosporin derivatives bearing oxazolidinone moiety

Several oxazolidinones having amine moiety were prepared to form a quaternary ammonium salt with cephalosporin nucleus, and antibacterial activity of the quaternary ammonium cephalosporin derivatives bearing oxazolidinone moiety were examined particularly with expectation of dual activity. However, the cephalosporin-oxazolidinone compounds revealed rather weaker antibacterial activity in vitro than their parent oxazolidinone and cephalosporin without showing any characteristic activity as expected.     

Expression of the recombinantKlebsiella aerogenes UreF protein as a MalE fusion

Expression of the active urease of the enterobacterium, Klebsiella aerogenes, requires the presence of the accessory genes (ureD, ureE, ureF, and ureG) in addition to the three structural genes (ureA, ureB, and ureC). These accessory genes are involved in functional assembly of the nickel-metallocenter for the enzyme. Characterization of ureF gene has been hindered, however, since the UreF protein is produced in only minute amount compared to other urease gene products. In order to overexpress the ureF gene, a recombinant pMAL-UreF plasmid was constructed from which the UreF was produced as a fusion with maltose-binding protein. The MBP-UreF fusion protein was purified by using an amylose-affinity column chromatography followed by an anion exchange column chromatography. Polyclonal antibodies raised against the fusion protein were purified and shown to specifically recognize both MBP and UreF peptides. The UreF protein was shown to be unstable when separated from MBP by digestion with factor Xa.     

Synthesis of 4-hydroxy-1-thiocoumarin derivatives-1: An efficient synthesis of thioflocoumafen

An efficient procedure for the preparation of 4-hydroxy-3-{1,2,3,4-tetra-hydro-3-[4-(4-triflu-oromethylbenzyl oxy)phenyl]-1-naphthyl}thiocoumarin (thioflocoumafen, 1a and 1b) is described. The key step in the synthesis involves the condensation reaction of 3-(4-methoxyphenyl)-1-tetralol (2) with 4-hydroxy-1-thiocoumarin (3).     

Synthesis andin vitro antibacterial activity of C-3′ pyridinium cephalosporin derivatives

The quaternary ammonium cephalosporin derivatives were prepared with various pyridines substituted at the 3 or/and 4 position. Their in vitro antibacterial activities were determined and substituent effect on pyridine nucleus was studied. Preparation of substituted pyridines are also described.     

Cytotoxicity of urushiols isolated from sap of Korean lacquer tree (Rhus vernicifera stokes)

Cytotoxicities of four urushiols, congeners isolated from the sap of Korean lacquer tree (Rhus vernicifera Stokes), to 29 human cancer cell lines originated from 9 organs were evaluated. Their values of 50% growth inhibition were below 4 microg/ml, and showed cell line specific cytotoxicity. The present result is the first report on the cytotoxicity of urushiols suggesting that they would have an anticancer activity to human cancer cells.     

Intraoperative laparoscopic complications

PURPOSE: The aim of this study was to assess various intraoperative and postoperative complications associated with laparoscopic colorectal surgery. Specifically, the impact of surgical experience and procedure type on complications was analyzed. METHODS: All patients who underwent laparoscopic surgery were analyzed by age, sex, surgical indications, procedure performed, procedure length, intraoperative and postoperative complications, incidence and causes for conversion, duration of postoperative ileus, and length of hospital stay. Patients were classified for type of procedure and chronologically into four consecutive groups. Procedures were also categorized into four different groups: GI, total abdominal colectomies; GII, segmental resections; GIII, diverting procedures; GIV, others (abdominoperineal resection, Hartmann's creation or closure, anterior resection, and rectopexy). RESULTS: Between August 1991 and October 1995, 167 patients of a mean age of 49.6 (15–88) years underwent laparoscopic colorectal procedures. All procedures were electively performed. Common indications for surgery included inflammatory disease in 70 (42 percent), neoplasia in 56 (33 percent), functional bowel disorders in 30 (18 percent), and other forms of colorectal disorders in 11 (7 percent) patients. The most significant variable affecting intraoperative laparoscopic complication rate was surgical experience measured as the time interval during which surgery was performed (P=0.02). Total complication rate decreased from 29 percent during the first period to 11 percent by the second period (P<0.04) and 7 percent during the third period (P<0.005). Thus, the learning curve appeared to have required more than 50 cases to achieve. Moreover, even after performance of 94 (1991–1993) procedures in GI and GIV, these procedures were associated with higher complication rates than were those procedures in GII and GIII (P=0.04). CONCLUSION: Surgical experience and case selection are the most critical variables by which the surgeon can decrease the intraoperative laparoscopic complication rate.     

Interfractional variation in position of the uterus during radical radiotherapy for cervical cancer.

BACKGROUND AND PURPOSE: This study was conducted to investigate the positional change of the uterus during radiotherapy which can degrade the accuracy of three-dimensional conformal radiotherapy (3DCRT) and intensity modulated radiotherapy (IMRT). PATIENTS AND METHODS: Sixty-six patients received radical radiotherapy for cervical cancer in Samsung Medical Center. For each patient, two MRI scans were taken; one was before beginning radiotherapy and the other was in the third or fourth week of radiotherapy. In T2-weighted MRI images, the positional change of the uterus was quantified by measuring six parameters; the distance from the external uterine opening to the isthmus of the uterus (Dcx), the distance from the isthmus of the uterus to the uterine fundus (Dco), the perpendicular distance of the uterine body to the uterine corpus (Dco-per), the angle between the vertical line and the cervical canal in sagittal images (Acx), the uterine corpus angle from the vertical line in sagittal plan (Aco), the angle between the uterine corpus from an arbitrary bony landmark and a vertical mid line in axial images (Aco-axi) RESULTS: Mean value of change in Dcx+Dco of tumor size during treatment was 8.0 mm in small tumors and 17.9 mm in large tumors. Among 44 anteflexed uterus patients, 5 changed into a retroflexed position. 12 patients (18%) had a greater than 30 degrees variation in any angle. For patients under 60 years, the difference in Acx was statistically significant. CONCLUSIONS: Positional changes of the uterus during radiotherapy should be considered in the treatment planning of 3DCRT or IMRT, particularly in patients under 60 years or those with tumor size greater than 4 cm in diameter.     

Expression of placental growth factor gene in lung cancer.

Differences in the gene expression profiles in small cell lung cancers (SCLC) and non-small cell lung cancers (NSCLC) may explain their different clinical characteristics. The aims of this study were (1) to identify genes differentially expressed in SCLC and NSCLC using mRNA differential display, and (2) to determine the clinical relevance of such genes in lung cancer. RNA differential display using three SCLC and six non-SCLC cell lines was used to identify a differentially expressed gene. Differential expression of the gene was confirmed in additional lung cancer cell lines using RT-PCR. Immunohistochemical staining for the gene product was performed on paraffin-embedded tissue from lung cancer patients. We examined the relationship between the expression of the gene and clinical parameters, including disease stage, response to treatment and survival time. The placental growth factor (PGF) gene was identified as preferentially expressed in SCLC compared with NSCLC cell lines using mRNA differential display. Further analysis of 45 lung cancer cell lines using RT-PCR showed that the placental growth factor (PGF) gene was expressed in nine of 13 SCLC cell lines (69%) and five of 32 NSCLC cell lines (15.6%) (p < 0.001, Fisher's exact test). Immunohistochemistry using anti-PGF antibody on the paraffin blocks from lung cancer patients showed that PGF expression was significantly higher in SCLC than NSCLC tissue sections (32 vs. 5.6%, p = 0.041, Fisher's exact test). Expression of PGF protein did not correlate with disease stage, response to treatment or survival time in SCLC patients. The present study suggests there is higher expression of PGF in SCLC compared to NSCLC. It may be that higher expression of the angiogenic factor PGF contributes to differences between the progression of SCLC and NSCLC, especially in regard to the nature of SCLC metastasis.