[Upper urinary tract MRI]

New MRI modalities today available allow exploration of many kidney diseases. Main developments have been made in the diagnosis of small tumors and tumoral extension of huge masses. The other important way of application is MR urography which perfectly show the dilated urinary tract in few seconds. Their potential application are for renal insufficiency, allergic reaction to iodine contrast media and in cases of contra indication to ionised radiations. It is a complementary sequence to assess the urinary tract in pelvic exploration. The evaluation of kidney function will be possible in the near future.

Duplex Doppler sonography of the flaccid penis: potential role in the evaluation of impotence

PURPOSE

Duplex Doppler sonography of the cavernosal arteries of the penis with intracavernous injection (ICI) of vasoactive agents has been widely used to evaluate arterial insufficiency in impotence. Our goal was to assess the potential value of peak systolic velocity (PSV) measurements on the flaccid penis in the diagnosis of arteriogenic impotence.

METHODS

Forty-four men underwent duplex Doppler sonography with PSV measurements before and after ICI of prostaglandin E(1). Three different cutoff values for lowest normal PSV before injection-5 cm/second, 10 cm/second, and 15 cm/second-were tested.

RESULTS

Thirteen patients had arteriogenic insufficiency based on post-ICI duplex sonography and clinical response. Results for our different cutoff PSV values of 5 cm/second, 10 cm/second, and 15 cm/second in diagnosing arteriogenic impotence were, respectively: sensitivity 29%, 96%, and 100%; specificity 100%, 92%, and 23%; negative predictive value 80%, 92%, and 100%; positive predictive value 100%, 81%, and 41%; and overall accuracy 79%, 93%, and 44%. In the flaccid state, there was a significant difference in mean PSV between the "normal" group (12.6 +/- 0.9 cm/second) and the arteriogenic impotence group (7.7 +/- 1.1 cm/second). Twenty-nine patients with a bilateral PSV of 10 cm/second or less before ICI had a normal clinical response.

CONCLUSIONS

A cutoff PSV value of 10 cm/second in the flaccid state had the best accuracy in predicting arterial insufficiency. Duplex Doppler sonography is proposed as the initial test to evaluate the penile arterial supply and to determine whether patients are good candidates for therapy with ICI.

Surface Activity and Chemistry of Thermal Carbon Blacks

The surface energy of thermal and furnace carbon blacks was determined by inverse gas chromatography (IGC) at infinite dilution. In general, the specific surface energy decreases with decreasing carbon black specific surface area. However, there is also an influence of the concentration of impurities during the carbon black production. The surface energy decreases with decreasing concentration of impurities. The carbon black surface and bulk chemistry was studied by electron spectroscopy for chemical analysis (ESCA), secondary ion mass spectroscopy (SIMS) and Raman spectroscopy. Scanning tunnelling microscopy (STM) was used for characterization of the surface morphology. Thermal grades of carbon black produced from high purity natural gas feedstock do not contain fewer surface functional groups than the other grades. No correlation between the concentration and nature of the oxygen and sulphur surface groups and the carbon black surface energy was found. Instead, a correlation between the surface energy and the polyaromatic character of the carbon black surface exists. Both increased in the order: thermal blacks from high purity natural gas feedstock < thermal black from oil feedstock < furnace blacks. The increase of the surface energy might be related to the formation of active sites which are formed upon removal of non-carbon elements during the carbon black formation. There was no principal difference in the surface morphology of thermal blacks from high purity gas feedstock and other blacks.

The TSC1 tumour suppressor hamartin regulates cell adhesion through ERM proteins and the GTPase Rho

Loss of the tumour-suppressor gene TSC1 is responsible for hamartoma development in tuberous sclerosis complex (TSC), which renders several organs susceptible to benign tumours. Hamartin, the protein encoded by TSC1, contains a coiled-coil domain and is expressed in most adult tissues, although its function is unknown. Here we show that hamartin interacts with the ezrin-radixin-moesin (ERM) family of actin-binding proteins. Inhibition of hamartin function in cells containing focal adhesions results in loss of adhesion to the cell substrate, whereas overexpression of hamartin in cells lacking focal adhesions results in activation of the small GTP-binding protein Rho, assembly of actin stress fibres and formation of focal adhesions. Interaction of endogenous hamartin with ERM-family proteins is required for activation of Rho by serum or by lysophosphatidic acid (LPA). Our data indicate that disruption of adhesion to the cell matrix through loss of hamartin may initiate the development of TSC hamartomas and that a Rho-mediated signalling pathway regulating cell adhesion may constitute a rate-limiting step in tumour formation.

A theorist envisions the future and speaks to nursing administrators

Planning for a preferred future for nursing is based on a vision of the world of the 21st century. A theorist shares her vision that stems from themes of scientific changes in cosmology and quantum theory, as well as her thoughtful reconsideration of the assumptions of her work for the future. These insights provide principles for planning that the nursing administrator can use for change at individual, institutional, and societal levels.

Murine CD1d-restricted T cell recognition of cellular lipids

NKT cells are associated with immunological control of autoimmune disease and cancer and can recognize cell surface mCD1d without addition of exogenous antigens. Cellular antigens presented by mCD1d have not been identified, although NKT cells can recognize a synthetic glycolipid, alpha-GalCer. Here we show that after addition of a lipid extract from a tumor cell line, plate-bound mCD1d molecules stimulated an NKT cell hybridoma. This hybridoma also responded strongly to three purified phospholipids, but failed to recognize alpha-GalCer. Seven of sixteen other mCD1d restricted hybridomas also showed a response to certain purified phospholipids. These findings suggest NKT cells can recognize cellular antigens distinct from alpha-GalCer and identify phospholipids as potential self-antigens presented by mCD1d.

Use of antibodies in the analysis of connexin 43 turnover and phosphorylation

A series of antipeptide antibodies designed to recognize specific sequences of the gap junction protein connexin 43 (Cx43) were developed and characterized immunochemically and immunohistologically. These antibodies bound to gap junctions and, on Western blots, to 43-kDa (often resolved as a doublet) and 41-kDa proteins in samples from heart, leptomeningeal cells, and brain. Relatively little of the 41-kDa protein was detectable in heart homogenates. Cultured rat leptomeningeal cells expressed high levels of the gap junction protein Cx43 and were used to analyze its turnover and phosphorylation. Pulse-chase experiments in leptomeningeal cells with [(35)S]methionine indicated that the 41-kDa form of connexin 43 was the first immunoprecipitable translation product. Radiolabel subsequently appeared in the lower band of the doublet at 43 kDa, followed by a shift into the higher band and turnover of the protein with a t(1/2) of 2.7 h. Pulse-chase labeling with [(32)P]P(i) indicated that phosphorylation of connexin 43 was limited to the 43-kDa protein, with a t(1/2) of 1.7 h. Treatment with alkaline phosphatase shifted the apparent molecular mass of the 43-kDa protein doublet such that it comigrated with the 41-kDa form. Hence, the 43-kDa protein observed on Western blots of both leptomeningeal cells and heart arises by phosphorylation of the 41 kDa precursor. Phosphorylation of serine residues accounts for most, if not all, of Cx43 phosphorylation in this system.

A preventive program for community-dwelling elderly at risk of functional decline: a pilot study

A program has been designed to assess and survey community-dwelling elderly over 75, identified at risk of functional decline by a postal questionnaire. The objectives were to verify the acceptability and the feasability of the program and to explore its impact, mainly on the functional status. A randomized controlled study took place in an urban community where 99 participants were drawn from those having responded positively to two or more of the six questions asked in the postal questionnaire, previously studied in Sherbrooke, in 1992. The program consisted in a home visit by a nurse who administered a standardized assessment battery on risk factors identified specifically for functional decline. When problems were identified, experimental subjects were referred to their general practitioner or to other health professionals for diagnosis and interventions. The control subjects received the usual health services. Both process and outcome measures were utilized in the study. The process measures allowed to know whether the program was acceptable or not to subjects and if it was feasible when using the existing health care services. The outcome measures included the number of eliminated risk factors, the functional autonomy level, the general well-being, the perceived state of health and the social support. The results showed that the program was feasible to implement and acceptable by the subjects and by health professionals. After 6 months, study subjects did not loose autonomy whereas the control ones significantly declined (P<0.001). If preventive programs could be effective in reducing the loss of autonomy, the use and cost of health care services could also be reduced and the other health and wellfare problems could be also prevented.

Involvement of ezrin/moesin in de novo actin assembly on phagosomal membranes

The current study focuses on the molecular mechanisms responsible for actin assembly on a defined membrane surface: the phagosome. Mature phagosomes were surrounded by filamentous actin in vivo in two different cell types. Fluorescence microscopy was used to study in vitro actin nucleation/polymerization (assembly) on the surface of phagosomes isolated from J774 mouse macrophages. In order to prevent non-specific actin polymerization during the assay, fluorescent G-actin was mixed with thymosin beta4. The cytoplasmic side of phagosomes induced de novo assembly and barbed end growth of actin filaments. This activity varied cyclically with the maturation state of phagosomes, both in vivo and in vitro. Peripheral membrane proteins are crucial components of this actin assembly machinery, and we demonstrate a role for ezrin and/or moesin in this process. We propose that this actin assembly process facilitates phagosome/endosome aggregation prior to membrane fusion.

The visible and invisible fields that shape the future of the nursing care system

Nursing care systems, past and future, are shaped by issues, trends, and visions that are both visible and invisible. The founding of Nursing Administration Quarterly twenty-five years ago was a visionary response to identify contemporary issues and predict future trends effectively. The vision stemmed from the deep values and commitment about the role of nursing administration in the health care system. Likewise nurse administrators of the 21st century face the challenge of shaping continuity and change within a unique set of issues and trends that call for new visions. The issues and trends are only part of the fields, or nonphysical forces, that nurse administrators use to shape the future of nursing care systems. The focus of this article is to examine both visible and invisible forces for determining the future. Key issues and trends are looked at from the perspective of personal and professional values and commitments. The purpose of exploring this perspective is to stimulate thinking about strategies to create possible and plausible futures.

Natural history of residual renal stone fragments after ESWL

OBJECTIVE

After extracorporeal shock wave lithotripsy (ESWL), residual fragments (RF) 4 mm or less are usually considered as clinically insignificant. We retrospectively reviewed the natural history and clinical significance of 97 noninfected and isolated RF (4 mm or less) observed 3 months after the last ESWL session on renal tomography.

PATIENTS AND METHODS

They represented 83 among 1, 216 patients treated by ESWL over a 9-year period (1989-1997). These RF were mostly localized in the inferior calyx (62%). Median follow-up was 40.6 months (range: 7-96 months). Renal tomography was always performed at the end of follow-up.

RESULTS

Stone-free status, or a decreased, stable or increased amount of residual stone occurred in 27 (33%), 1 (1%), 24 (29%) and 31 (37%) of the 83 patients, respectively. During this study, 18 patients (22%) were proposed for a complementary treatment related to a size increase of the residual fragments (13 ESWL, 1 retrograde endoscopy, 3 percutaneous nephrolithotomy, and 1 polar inferior nephrectomy).

CONCLUSION

The term clinically insignificant should not be employed to describe RF after ESWL. Efforts should be performed to obtain true stone-free status after ESWL.

Correlations between reported and measured ultraviolet radiation exposure of mothers and young children

Cumulative and intermittent sun exposure are risk factors for skin cancer, highlighting the need to monitor exposure during childhood. There is currently very little available information concerning the accuracy of self-reported levels of sun exposure, particularly for very young children. In this study, UV radiation (UVR) exposure measured by polysulfone dosimeters worn on the wrist was compared with a measure of estimated exposure using a diary based on recall at the end of the 4 day study period and ambient dosimetric measures. Results of the study indicate that the relative UVR exposures expressed as a fraction of daily total ambient received during the 4 day period by young children and mothers are similar. A high level of association was obtained for the estimated levels of exposure between young children and their mothers. Moderate correlations were evident for dosimeter readings of mother and child on weekends with no significant association on weekdays. The association between estimated exposure and dosimeter readings was poor and needs improvement. This may be achieved by greater consideration of structural and environmental factors that influence the levels of UVR exposure received by individuals and by increasing the level of specificity in the measurement instruments. Methodological issues such as recall of exposure after several days, quantity of sun exposure and more precise measurement of grades of exposure when outside may have more impact than previously expected, and further information is being sought with a larger sample for exposure during the summer months.

Clinical utility of lipid and lipoprotein levels during hospitalization for acute myocardial infarction

The management of dyslipidemia after myocardial infarction (MI) is an important aspect of post-myocardial infarction care. However, acute changes in the lipid profile immediately following myocardial infarction have resulted in uncertainty regarding the clinical utility of lipid levels assessed during hospitalization for MI. We studied the effect of the timing of plasma lipid assessment among 294 patients who presented with MI to determine whether the differences between the serum lipid values in-hospital when compared with post-discharge values (generally 2-3 months after MI) would have a substantial impact on the decision to initiate lipid-lowering therapy. We found that the mean total and LDL cholesterol levels were significantly lower in-hospital when compared with generally 2-3 months later. However, patients whose lipids were measured within 48 h of presentation did not have significantly different values compared with generally 2-3 months post-discharge. Moreover, despite slightly lower in-hospital levels, 83.7% of patients were above the National Cholesterol Education Program target LDL for secondary prevention and 57.6% met the criteria for drug therapy based on in-hospital assessment. Total and LDL cholesterol levels fall modestly after an acute MI; however, from a clinical perspective, in-hospital levels can be used to guide decisions regarding lipid-lowering therapy which can begin in the immediate post-MI setting. In-hospital levels approximate post-MI levels, particularly if drawn within 48 h of presentation. All patients with acute myocardial infarction should have complete lipid profiles measured prior to discharge.

Performance of selected microbial pectinases on synthetic monomethyl-esterified di- and trigalacturonates

Two monomethyl esters of alpha-(1-4)-linked D-galacturonic dimers and three monomethyl esters of alpha-(1-4)-linked D-galacturonic acid trimers were synthesized chemically and further used as substrates in order to establish the substrate specificity of six different endopolygalacturonases from Aspergillus niger, one exopolygalacturonase from Aspergillus tubingensis, and four selected Erwinia chrysanthemi pectinases; exopolygalacturonan hydrolase X (PehX), exopolygalacturonate lyase X (PelX), exopectate lyase W (PelW), and oligogalacturonan lyase (Ogl). All A. niger endopolygalacturonases (PGs) were unable to hydrolyze the two monomethyldigalacturonates and 2-methyltrigalacturonate, whereas 1-methyltrigalacturonate was only cleaved by PGI, PGII, and PGB albeit at an extremely low rate. The hydrolysis of 3-methyltrigalacturonate into 2-methyldigalacturonate and galacturonate by all endopolygalacturonases demonstrates that these enzymes can accommodate a methylgalacturonate at subsite -2. The A. tubingensis exopolygalacturonase hydrolyzed the monomethyl-esterified digalacturonates and trigalacturonates although at lower rates than for the corresponding oligogalacturonates. 1-Methyltrigalacturonate was hydrolyzed at the same rate as trigalacturonate which demonstrates that the presence of a methyl ester at the third galacturonic acid from the nonreducing end does not have any effect on the performance of exopolygalacturonase. Of the four E. chrysanthemi pectinases, Ogl was the only enzyme able to cleave digalacturonate, whereas all four enzymes cleaved trigalacturonate. Ogl does not cleave monomethyl-esterified digalacturonate and trigalacturonate in case the second galacturonic acid residue from the reducing end is methyl-esterified. PehX did not hydrolyze any of the monomethyl-esterified trigalacturonates. The two lyases, PelX and PelW, were both only able to cleave 1-methyltrigalacturonate into Delta4,5-unsaturated 1-methyldigalacturonate and galacturonate.

Ambient solar UVR, personal exposure and protection

Ambient solar ultraviolet radiation (UVR) has been monitored around Australia by the Australian Radiation Laboratory (ARL) and its successor ARPANSA since the mid 1980's using a network of radiometric detectors and a spectroradiometer (SRM) for spectral measurements, based in Melbourne. In a continent the size of Australia, the levels vary markedly, basically following a latitude gradient increasing towards the equator but with local geographical and weather effects also evident. ARL also conducts personal exposure studies of various population groups in collaboration with other research centres to gather information on what fraction of the ambient UVR people receive. ARL also undertakes studies on the UVR protection provided by sunscreens, clothing, hats, sunglasses and other materials in an attempt to improve UVR protection used by the public.

Mechanical strain increases velocity and extent of shortening in cultured airway smooth muscle cells

Abnormal mechanical stress on lung tissue is associated with increased mass and contractility of airway smooth muscle (ASM). We have reported that cultured ASM cells subjected to cyclic strain exhibit increased myosin light chain kinase (MLCK) and stress filaments. Increased MLCK may increase contractile velocity, whereas increased stress filaments could impede cell shortening by increasing the cell's internal load. To study strain-induced changes in cell contractility, the time course of shortening of individual cells exposed to 90 mM KCl was recorded. Length vs. time plots revealed significantly greater maximal velocity of shortening in strain cells than control (no strain). This correlated with an increase in MLCK and myosin light chain phosphorylation measured in strain cells in separate experiments. The extent of cell shortening tended to be greater in the strain cells so that increased impedance to shortening was not detected. Mechanical stress may therefore increase the contractility of ASM by increasing the content of MLCK.

"Fast-tracking" in patients undergoing coronary artery surgery with severely impaired left ventricular function

Cost containment and efficient resource utilization are motivating anaesthesiologists to early tracheal extubation of cardiac surgical patients. Fast track cardiac anaesthesia is both safe and cost-effective. We studied 45 patients with LVEF = 40% who underwent coronary revascularization and were put on the same fast track principle as those with normal ventricular function. Of these 31 patients (68.8%) had recent (<2 weeks) cardiac events requiring hospitalization. Acute myocardial infarction was documented in 8 patients (17.7%) and 23 (51.1%) had unstable angina. Congestive failure was present in 13 (28.9%) patients. Preoperative intravenous pharmacological support was needed in 17 (37.7%) patients, mechanical ventilation in 2 (4.5%) and IABP support in 1 (2.3%) patient. Anaesthetic management of these patients hinged on reduced usage of narcotics and muscle relaxants to facilitate early extubation. Operative strategy adopted was that of optimal revascularization. Beating heart surgery was adopted particularly in patients with low ejection fraction to avoid the attendant systemic and myocardial ill effects of cardiopulmonary bypass (CPB), especially in those who have had recent myocardial insults. Coronary surgery was performed on beating heart in 18 (40%) patients, while the other 27 (60%) patients were revascularised on CPB support. Of the 44 operative survivors, early extubation (<4 hours) was performed in 37 (84%) patients. Only 7 (16%) patients required ventilation for more than 24 hours. 3 out of these 7 patients were ventilated due to pulmonary reason and other 4 were ventilated since they were on IABP support. ICU stay was less than 24 hrs for 34/42 (80.9%) and hospital stay less than 6 days in 24/40 (60%). Fast tracking in cardiac surgery can be achieved with safety even in patients with impaired LV function.