Treatment of bacterial biofilms on polymeric biomaterials using antibiotics and ultrasound

New studies on the effect of frequency and duration of exposure upon the ultrasonic enhanced action of gentamicin against biofilms of Escherichia coli are presented in this paper. Ultrasound was applied at clinical levels which would not harm human tissue. The study on frequency indicated that lower frequencies produce higher levels of killing. The results of the timed experiment indicate that complete sterilization of a 14-h biofilm can be achieved after 6 h of exposure. These findings are significant because they show that biofilms can be reduced to zero reproductive ability as assessed by plate counting.     

Lower caliceal stone clearance after shock wave lithotripsy or ureteroscopy: the impact of lower pole radiographic anatomy

PURPOSE: We determine whether there is a significant relationship between the spatial anatomy of the lower pole, as seen on preoperative excretory urography (IVP), and the outcome after shock wave lithotripsy or ureteroscopy for a solitary lower pole caliceal stone 15 mm. or less. MATERIALS AND METHODS: Between January 1992 and June 1996, 34 patients with 15 mm. or less solitary lower pole stone underwent ureteroscopy with intracorporeal lithotripsy (13) or extracorporeal shock wave lithotripsy (ESWL) with a Dornier HM3 lithotriptor (21). On pretreatment IVP lower pole infundibular length and width, infundibulopelvic angle of the stone bearing calix were measured. Stone size and area were determined from an abdominal plain x-ray. A plain x-ray of the kidneys, ureters and bladder was obtained in all patients at a median followup of 12.3 and 8 months in the ureteroscopy and ESWL groups, respectively. RESULTS: After initial therapy the overall stone-free rate was 62 and 52% in the ureteroscopy and ESWL groups, respectively. Stone-free status after ESWL was significantly related to each anatomical measurement. Infundibulopelvic angle 90 degrees or greater, and infundibular length less than 3 cm. and width greater than 5 mm. were each noted to correlate with an improved stone-free rate after ESWL. In contrast, the stone-free rate after ureteroscopy was not statistically significantly impacted by these anatomical features, although a clinical stone-free trend was identified relating to a favorable infundibular length and infundibulopelvic angle. The infundibulopelvic angle was 90 degrees or greater in 4 stone-free patients (12% overall), including 2 who underwent ureteroscopy and 2 who underwent ESWL. On the other hand, in 2 and 4 stone-free patients (18% overall) who underwent ureteroscopy and ESWL, respectively, favorable radiographic features consisted of a short, wide but acutely angulated infundibulum with the infundibulopelvic angle less than 90 degrees, and infundibular length less than 3 cm. and width 5 mm. or greater. In contrast, in 4 and 6 patients (29% overall) who underwent ureteroscopy and ESWL, respectively, all 3 radiographic features were unfavorable with the infundibulopelvic angle less than 90 degrees, and infundibular length greater than 3 cm. and width less than 5 mm. In these cases the stone-free rate was 50 and 17% after ureteroscopy and ESWL, respectively. CONCLUSIONS: The 3 major radiographic features of the lower pole calix (infundibulopelvic angle, and infundibular length and width) can be easily measured on standard IVP using a ruler and protractor. Each factor individually has a statistically significant influence on stone clearance after ESWL. A wide infundibulopelvic angle or short infundibular length and broad infundibular width regardless of infundibulopelvic angle are significant favorable factors for stone clearance following ESWL. Conversely, these factors have a cumulatively negative effect on the stone clearance rate after ESWL when they are all unfavorable. In ureteroscopy spatial anatomy has less of a role in regard to stone clearance but it may have a negative impact when there is uniformly unfavorable anatomy.     

Benign breast changes and the risk for subsequent breast cancer: an update of the 1985 consensus statement. Cancer Committee of the College of American Pathologists

The Cancer Committee of the College of American Pathologists has prepared an update of the consensus statement on premalignant breast lesions and breast cancer risk that was originally published in the Archives of Pathology & Laboratory Medicine in 1986. The objective of this publication is to better define the relative breast cancer risk associated with specific histologic abnormalities by incorporating data derived from recent case-control studies. Explanatory notes are used to document and explain specific risk classifications. In addition to refining the degree of risk associated with individual lesions, such as fibroadenoma and atypical hyperplasia, this update includes a discussion of age-specific breast cancer risk and provides examples that can be used when counseling patients.     

TLS/FUS, a pro-oncogene involved in multiple chromosomal translocations, is a novel regulator of BCR/ABL-mediated leukemogenesis

The leukemogenic potential of BCR/ABL oncoproteins depends on their tyrosine kinase activity and involves the activation of several downstream effectors, some of which are essential for cell transformation. Using electrophoretic mobility shift assays and Southwestern blot analyses with a double-stranded oligonucleotide containing a zinc finger consensus sequence, we identified a 68 kDa DNA-binding protein specifically induced by BCR/ABL. The peptide sequence of the affinity-purified protein was identical to that of the RNA-binding protein FUS (also called TLS). Binding activity of FUS required a functional BCR/ABL tyrosine kinase necessary to induce PKCbetaII-dependent FUS phosphorylation. Moreover, suppression of PKCbetaII activity in BCR/ABL-expressing cells by treatment with the PKCbetaII inhibitor CGP53353, or by expression of a dominant-negative PKCbetaII, markedly impaired the ability of FUS to bind DNA. Suppression of FUS expression in myeloid precursor 32Dcl3 cells transfected with a FUS antisense construct was associated with upregulation of the granulocyte-colony stimulating factor receptor (G-CSFR) and downregulation of interleukin-3 receptor (IL-3R) beta-chain expression, and accelerated G-CSF-stimulated differentiation. Downregulation of FUS expression in BCR/ABL-expressing 32Dcl3 cells was associated with suppression of growth factor-independent colony formation, restoration of G-CSF-induced granulocytic differentiation and reduced tumorigenic potential in vivo. Together, these results suggest that FUS might function as a regulator of BCR/ABL leukemogenesis, promoting growth factor independence and preventing differentiation via modulation of cytokine receptor expression.     

Nitric oxide prevents IL-1beta and IFN-gamma-inducing factor (IL-18) release from macrophages by inhibiting caspase-1 (IL-1beta-converting enzyme)

Procytokine processing by caspase-1 is required for the maturation and release of IL-1beta and IFN-gamma-inducing factor (IGIF) (or IL-18) from activated macrophages (Mphi). Nitric oxide (NO) has emerged as a potent inhibitor of cysteine proteases. Here, we tested the hypothesis that NO regulates cytokine release by inhibiting IL-1beta-converting enzyme (ICE) or caspase-1 activity. Activated RAW264.7 cells released four to five times more IL-1beta, but not TNF-alpha, in the presence of the NO synthase inhibitor N(G)-monomethyl-L-arginine. Stimulated peritoneal Mphi from wild-type mice (inducible NO synthase (iNOS)+/+) also released more IL-1beta if exposed to N(G)-monomethyl-L-arginine, whereas Mphi from iNOS knockout mice (iNOS-/-) did not. Inhibition of NO synthesis in stimulated RAW264.7 cells also resulted in a threefold increase in intracellular caspase-1 activity. The NO donor S-nitroso-N-acetyl-DL-penicillamine inhibited caspase-1 activity in cells as well as the activity of purified recombinant caspase-1 and also prevented the cleavage of pro-IL-1beta and pro-IGIF by recombinant caspase-1. The inhibition of caspase-1 by NO was reversible by the addition of DTT, which is consistent with S-nitrosylation as the mechanism of caspase-1 inhibition. An in vivo role for the regulation of caspase-1 by NO was established in iNOS knockout animals, which exhibited significantly higher plasma levels of IL-1beta and IFN-gamma than their wild-type counterparts at 10 h following LPS injection. Taken together, these data indicate that NO suppresses IL-1beta and IGIF processing by inhibiting caspase-1 activity, providing evidence for a unique role for induced NO in regulating IL-1beta and IGIF release.     

Modification of the beta- and alpha2-adrenergic sensitivity of rat submandibular glands by environmental stimuli and stress

In man, the rate of resting salivary secretion can be influenced by environmental stimuli related to light dark cycles or by noxious stimuli (stressors) of psychological origin. The sympathetic branch of the autonomic nervous system and the adrenal medulla play an important part in homeostatic responses. Previous observations have shown that chronic exposure of rats to constant light promotes degranulation of parotid acini and desensitization of submandibular beta-adrenergic receptors. Now the submandibular secretory response elicited by beta- and alpha2-adrenergic agonists was studied in rats chronically exposed to environmental conditions that modified the activities of sympathetic efferents to the pineal, salivary and adrenal glands. Adult male rats were exposed to constant light (LL) or constant darkness (DD) for 20 days, or to stress (2 h daily immobilization) for 14 days. Control animals were kept under the usual lighting conditions and without immobilization. Dose response curves to isoproterenol (i.v), before and after administration (i.v.) of a dose (20 microg/kg) of clonidine were obtained. Beta-adrenergic desensitization was observed in all the experimental groups, while alpha2-adrenergic desensitization was only observed in the stress and LL groups. The results suggest that circulating catecholamines could mediate light and stress effects on submandibular beta-adrenergic secretory responses. Extrasynaptic alpha2-adrenoceptors might modulate the submandibular secretory response when predictable environmental stimuli (daily light phase) or unpredictable stressors raise the concentrations of circulating catecholamines.     

The dusty atmosphere of the brown dwarf Gliese 229B

The brown dwarf Gliese 229B has an observable atmosphere too warm to contain ice clouds like those on Jupiter and too cool to contain silicate clouds like those on low-mass stars. These unique conditions permit visibility to higher pressures than possible in cool stars or planets. Gliese 229B's 0.85- to 1.0-micrometer spectrum indicates particulates deep in the atmosphere (10 to 50 bars) having optical properties of neither ice nor silicates. Their reddish color suggests an organic composition characteristic of aerosols in planetary stratospheres. The particles' mass fraction (10(-7)) agrees with a photochemical origin caused by incident radiation from the primary star and suggests the occurrence of processes native to planetary stratospheres.     

The female athlete. The triad of disordered eating, amenorrhoea and osteoporosis

The value of routine follow-up programs for patients with early stage breast cancer remains an area of controversy. In recent years, the cost-effectiveness of routine investigations has been questioned, and 2 prospective randomized clinical trials have shown no survival advantage to more intensive diagnostic follow-up approaches. Under the auspices of the Ottawa Regional Cancer Centre, a national survey of the practice patterns of Canadian surgical, radiation and medical oncologists was undertaken to measure current Canadian standards of care and to determine average costs of 5-year follow-up for patients completing primary treatment for stage I and II breast cancer. Standardized questionnaires were sent out to 130 surgeons, 59 radiation oncologists and 89 medical oncologists. The overall response rate was 44%. Based on the frequency of follow-up visits and investigations recommended by respondents, an average cost per patient for a 5-year follow-up plan was derived for each subspecialist group: $791, $911 and $904 for surgeons, radiation oncologists and medical oncologists respectively. Use of a less interventionist follow-up program was estimated to result in a cost saving of $300 per patient over 5 years. The results indicate that, for the most part, Canadian oncologists have been influenced by the available literature concerning follow-up practices and are ordering fewer routine tests. Further cost savings to the Canadian health care system could be achieved with the adoption of even less interventionist follow-up programs.     

Ecomycins, unique antimycotics from Pseudomonas viridiflava

While insulin is known to promote vascular smooth muscle (VSM) relaxation, it also enhances endothelin-1 (ET-1) secretion and action in conditions such as NIDDM and hypertension. We examined the effect of insulin pretreatment on intracellular free calcium ([Ca2+]i) responses to ET-1 in cultured aortic smooth muscle cells (ASMCs) isolated from Sprague-Dawley (SD) rats and measured ET(A) receptor characteristics and ET-1-evoked tension responses in aorta obtained from insulin-resistant, hyperinsulinemic Zucker-obese (ZO) and control Zucker-lean (ZL) rats. Pretreatment of rat ASMCs with insulin (10 nmol/l for 24 h) failed to affect basal [Ca2+]i levels but led to a significant increase in peak [Ca2+]i response (1.7-fold; P < 0.01) to ET-1. The responses to IRL-1620 (an ET(B) selective agonist), ANG II, and vasopressin remained unaffected. ET-1-evoked peak [Ca2+]i responses were significantly attenuated by the inclusion of the ET(A) antagonist, BQ123, in both groups. The ET(B) antagonist, BQ788, abolished [Ca2+]i responses to IRL-1620 but failed to affect the exaggerated [Ca2+]i responses to ET-1. Saturation binding studies revealed a twofold increase (P < 0.01) in maximal number of binding sites labeled by 125I-labeled ET-1 in insulin-pretreated cells and no significant differences in sites labeled by 125I-labeled IRL-1620 between control and treatment groups. Northern blot analysis revealed an increase in ET(A) mRNA levels after insulin pretreatment for 20 h, an effect that was blocked by genistein, actinomycin D, and cycloheximide. Maximal tension development to ET-1 was significantly greater (P < 0.01), and microsomal binding studies using [3H]BQ-123 revealed a twofold higher number of ET(A) specific binding sites (P < 0.01) in aorta from ZO rats compared with that of ZL rats. These data suggest that insulin exaggerates ET-1-evoked peak [Ca2+]i responses via increased vascular ET(A) receptor expression, which may contribute to enhanced vasoconstriction observed in hyperinsulinemic states.     

Effects of high oxygen concentrations on microbial biosensor signals. Hyperoxygenation by means of perfluorodecalin

Amperometric biosensors register oxygen depletion in response to analyte catabolism, and thus are limited by the availability of dissolved oxygen. Microbial sensors containing immobilized cells of Gluconobacter oxydans were hyperoxygenated to 400% of control levels and the effects on sensor responses to glucose were determined. Oxygenated perfluorodecalin (a completely fluorinated organic substance) was as effective in hyperoxygenation as direct sparging with O2, increasing sensor base medium oxygen concentrations from 9.3 to 37 mg/l. Hyperoxygenation enhanced maximal biosensor response amplitudes, particularly at high cell loading densities. Maximal response rates were also improved, although less dramatically. Results suggest that hyperoxygenation may be a new general approach for modulating biosensor responses.