X-ray photoelectron spectroscopy analysis of whole cells and isolated cell walls of gram-positive bacteria: comparison with biochemical analysis

The surface chemical composition of whole cells and isolated cell walls of four coryneform bacteria and of a Bacillus brevis strain has been determined by X-ray photoelectron spectroscopy (XPS). The XPS data were converted into concentrations of model compounds: peptides, polysaccharides, and hydrocarbonlike compounds. The composition of the surface of B. brevis differed markedly from that of coryneforms: the peptide concentration was about twice higher in the former case, which is attributed to the presence of an S-layer at the cell surface; in contrast, the surface of coryneforms was rich in hydrocarbonlike compounds (about 40%), which was concomitant with a high water contact angle. The peptide surface concentration of the isolated cell walls of the five strains deduced from XPS data fitted well with the total peptide content determined by biochemical analysis, which supports the validity of XPS to determine the overall macromolecular composition of the bacterial cell surface. Compared to biochemical analysis of isolated cell walls, XPS analysis of whole cells provides information which concerns directly the cell surface (2- to 5-nm-thick layer) and is less subject to alteration via losses of cell wall constituents or contamination by intracellular compounds.     

Gemcitabine: a cytidine analogue active against solid tumors

The pharmacology, pharmacokinetics, clinical efficacy, adverse effects, and dosage and administration of gemcitabine are reviewed. Gemcitabine is a deoxycytidine-analogue antimetabolite with activity against some solid tumors. Gemcitabine is phosphorylated intracellularly to difluorodeoxycytidine triphosphate, which terminates DNA-chain elongation and competitively inhibits DNA polymerase and ribonucleotide reductase. After i.v. administration, gemcitabine is rapidly distributed into total body water. The drug is deaminated in the plasma to inactive difluorodeoxyuridine; both gemcitabine and difluorodeoxyuridine are primarily renally eliminated. In clinical studies, gemcitabine reduced pain and improved function in patients with advanced pancreatic cancer. Gemcitabine has shown some activity against non-small-cell lung cancer, particularly when combined with cisplatin or ifosfamide. The agent has also shown modest activity against advanced ovarian and breast cancer. Adverse effects include dose-limiting myelosuppression, flu-like symptoms, nausea, vomiting, and rash. Gemcitabine has FDA-approved labeling for use in the treatment of locally advanced and metastatic pancreatic cancer. The recommended dosage for this indication is 1000 mg/m2 (as the hydrochloride salt) i.v. given over 30 minutes weekly for seven weeks, followed after one week of rest by 1000 mg/ m2 i.v. given over 30 minutes weekly for three weeks every four weeks. Gemcitabine palliates symptoms in patients with advanced or metastatic pancreatic cancer. More study is needed to determine gemcitabine's role in the treatment of non-small-cell lung cancer, ovarian cancer, and breast cancer.     

Experimental study on effect of shenyi xieli mixture on nature killer cell activity and lymphocyte reactivity to IL-2 in tumor mice

OBJECTIVE: To explore therapeutic mechanism of Shengyi Xieli Mixture (SYXLM) on malignant tumor. METHODS: Chemotherapy, radiotherapy and different doses of SYXLM were used to treat tumor mice [correction of rats]. RESULTS: SYXLM could enhance the nature killer (NK) cell activities of the tumor mice [correction of rats], and this effect was dose dependent (control group 52.70 +/- 6.01, SYXLM No. 1 group 59.01 +/- 10.00, SYXLM No. 2 group 78.33 +/- 10.90, P < 0.01). The NK cell activities of the tumor mice [correction of rats] were inhibited in the chemotherapy group alone, but they were enhanced in the group of chemotherapy combined with SYXLM (P < 0.05), the results were the same in the radiotherapy group alone and the group of radiotherapy combined with SYXLM (P < 0.05). The response of lymphocyte of the tumor mice [correction of rats] to IL-2 was enhanced significantly in SYXLM group compared with the control group. This response was enhanced insignificantly in the group in which radiotherapy combined with the SYXLM. CONCLUSION: The SYXLM could enhance the function of immune system of the tumor mice [correction of rats] and diminish or reduce the side effect of radiotherapy, chemotherapy to the immune system of the tumor mice [correction of rats].     

Chlorination and dechlorination of nuclear reactor cooling water

Effects from chlorination and dechlorination of Savannah River water were studied during the development of biofouling countermeasures for a proposed cooling tower system required for thermal mitigation of nuclear reactor cooling water effluent. Testing was conducted to assess chlorine demand and dissipation rates as well as the environmental acceptability of using sodium sulfite as a dechlorinating agent. Chlorine demand varied significantly, but in an unpredictable manner during seven seasonal sampling dates. A chlorine dosage of 3–5 mg/l was generally adequate to provide a free chlorine residual of 1 mg/l. Static 48-h bioassays with bluegill showed no acute toxicity for chlorinated/dechlorinated cooling water containing up to 64 times the calculated stoichiometric concentration of sodium sulfite required for dechlorination. Experiments measuring the depletion of dissolved oxygen and flow-through (96-h) bioassays with bluegill and largemouth bass further substantiated the environmental acceptability of using sodium sulfite as a dechlorinating agent.     

Involvement of calmodulin-dependent protein kinases-I and -IV in long-term potentiation

BACKGROUND: The Hemopump (DLP/Medtronic) has been in clinical use for about 7 years. There is still no adequate way of determining actual output from the three available pump systems in the clinical situation. If the pump is completely stopped during weaning from the device, there is a possibility of back-leakage through the pump, endangering the patient from regurgitation into the left ventricle. It can also make it more difficult to judge the recovery of heart function because of a volume load of the left ventricle. The aim of this study was to evaluate in a standardized, experimental in vitro model the output from three different-sized Hemopump catheters at various pressure levels and to quantify the back-flow through the pumps. METHODS: The Hemopump models were tested in an in vitro study regarding total outflow at various speeds at three pressure levels. The back-flow through the pumps was also measured with the pumps at a complete stop. RESULTS: The outflow from the Hemopumps ranged from 0.4 to 4.5 L/min, depending on which pump and speed were used. Variations in total output, depending on speed and various pressure settings, could be up to 0.4 L/min. Back-flow through the pump into the left ventricle may be as great as 1.6 L/min. CONCLUSIONS: The flow outputs from the different Hemopump models were reproducible over time and were closely related to the resistance of the model. The Hemopump, if not running, can induce substantial regurgitation through the pump into the left ventricle.     

Truncated human endothelin receptor A produced by alternative splicing and its expression in melanoma

PURPOSE: Traumatic sphincter disruption frequently is associated with a rectovaginal fistula, but the effect of a persistent sphincter defect on the outcome of rectovaginal fistula repair is poorly documented. We analyzed the outcome of rectovaginal fistula repairs based on preoperative sphincter status. PATIENTS AND METHODS: We identified 52 women who underwent 62 repairs of simple obstetrical rectovaginal fistulas between 1992 and 1995. Fourteen patients (27 percent) had preoperative endoanal ultrasound studies and 25 (48 percent) had anal manometry studies. Follow-up was by mailed questionnaire in 36 patients (69 percent) and by telephone interview in 12 (23 percent), for a total response rate of 92 percent. Median age was 30.5 (range, 18-70) years, and median follow-up was 15 (range, 0.5-123) months. Twenty-five patients (48 percent) complained of varying degrees of fecal incontinence before surgery. There were 27 endorectal advancement flaps and 35 sphincteroplasties (28 with and 8 without levatoroplasty). RESULTS: Success rates were 41 percent with endorectal advancement flaps and 80 percent with sphincteroplasties (96 percent success with and 33 percent without levatoroplasty; P = 0.0001). Endorectal advancement flap was successful in 50 percent of patients with normal sphincter function but in only 33 percent of patients with abnormal sphincter function (P = not significant). For sphincteroplasties, success rates were 73 vs. 84 percent for normal and abnormal sphincter function, respectively (P = not significant). Results were better after sphincteroplasties vs. endorectal advancement flaps in patients with sphincter defects identified by endoanal ultrasound (88 vs. 33 percent; P = not significant) and by manometry (86 vs. 33 percent; P = not significant). Poor results correlated with prior surgery in patients undergoing endorectal advancement flaps (45 percent vs. 25 percent; P = not significant) but not sphincteroplasties (80 vs. 75 percent; P = not significant). CONCLUSIONS: All patients with rectovaginal fistula should undergo preoperative evaluation for occult sphincter defects by endoanal ultrasound or anal manometry or both procedures. Local tissues are inadequate for endorectal advancement flap repairs in patients with sphincter defects and a history of previous repairs. Patients with clinical or anatomic sphincter defects should be treated by sphincteroplasty with levatoroplasty.     

Detection of nivalenol genotoxicity in cultured cells and multiple mouse organs by the alkaline single-cell gel electrophoresis assay

The effects of upper airway (UAW) flows and pressures on breathing pattern and respiratory muscle activities were studied in anesthetized rats breathing through a tracheostomy. A steady flow (approximately 1000 ml/kg/min) of cold dry air, or cold wet air, or warm wet air was passed through the UAW, in the expiratory direction for approximately 20 sec (20-40 sec). In other trials positive or negative pressure was applied to the isolated UAW for a similar duration. There was a marked prolongation of the expiratory duration and decreases in peak inspiratory flow, tidal volume, and peak diaphragm electromyogram (EMG) activity in response to cold dry airflow. The responses to cold wet air were reduced but still significant. Warm wet air had no effect on breathing. These responses show that UAW cooling and drying depress breathing in the rat and that cooling itself could cause the inhibition of breathing. Negative pressure induced substantial increases in genioglossus and laryngeal inspiratory activity while positive pressure caused a decrease in genioglossus activity. Positive pressure also increased expiratory time while negative pressure increased inspiratory time. These results confirm the functional role of the UAW dilating muscles in preventing UAW from collapse in rats.