Practice guidelines: the radiology perspective

Clinical practice guidelines have emerged as a reality for medical practitioners over the past 20 years. Although virtually all groups interested in the development of practice guidelines hope for improvements in patient care, secondary expectations vary widely among those using them. Their use in daily practice by physicians has met with resistance from barriers including concerns of “cookbook” medicine, a loss of autonomy, and increased professional liability. The recent experience of the ACR in addressing these challenges illustrates that physicians are receptive to steps perceived to mitigate the risks accompanying the use of guidelines as well as to efforts to increase their understanding of implementing guidelines in clinical practice. The experiences of other medical societies and an inventory of future trends reveal additional challenges associated with the use of practice guidelines, as third parties look to guidelines as points of reference for gauging the performance of health care providers.     

Distribution and function of cholinergic receptors in the sheep detrusor muscle

The distribution of cholinergic nerve fibres, as well as the characterization of the muscarinic receptors responsible for the contraction, were determined in the detrusor smooth muscle of the sheep. The results obtained demonstrated a rich presence of acetylcholinesterase (AChE)-positive fibres distributed throughout the bladder body forming dense neuromuscular, subepithelial and perivascular plexuses. Furthermore, intramural ganglia containing AChE-positive cell bodies were identified. However, acetylcholine and carbachol induced a dose-dependent contraction of detrusor smooth muscle. The effect observed with carbachol was competitively antagonized by atropine (pA2: 8.94), pirenzepine (pA2: 7.38), AF-DX 116 (pA2: 7.35), 4-DAMP (pA2: 9.26) and hexahydroxiladifenidol (HHSiD) (pA2: 8.49). The pA2 value for pirenzepine is intermediate between M1- and M2-receptors which suggests that this antagonist does not act on M1- or M2-receptors, but that it does on M3-receptors. The pA2 value for AF-DX 116 is consistent with the presence of M2-receptors in this tissue. Moreover, the pA2 values obtained for both 4-DAMP and HHSiD are in agreement with the presence of M3-receptors, due to the lack of effect of pirenzepine on M1-muscarinic receptors. These results indicate the existence of a rich parasympathetic innervation in the sheep detrusor muscle and suggest that its contraction could be mediated by the stimulation of muscarinic receptors belonging to both M3- and M2-subtypes.     

Relationship between oxidative stress and essential hypertension.

This study investigated the association of blood pressure with blood oxidative stress-related parameters in normotensive and hypertensive subjects. A cross-sectional design was applied to 31 hypertensive patients and 35 healthy normotensive subjects. All subjects were men between the ages of 35 and 60 years. Exclusion criteria were obesity, dyslipidemia, diabetes mellitus, smoking and current use of any medication. All patients underwent 24-h ambulatory blood pressure monitoring and sampling of blood and urine. Antioxidant enzymes activity, reduced/oxidized glutathione ratio (GSH/GSSG), and lipid peroxidation (malondialdehyde) were determined in erythrocytes. Parameters measured in the plasma of test subjects were plasma antioxidant status, lipid peroxidation (8-isoprostane), plasma vitamin C and E, and the blood pressure modulators renin, aldosterone, endothelin-1 and homocysteine. Daytime systolic and diastolic blood pressures of hypertensives were negatively correlated with plasma antioxidant capacity (r=-0.46, p<0.009 and r=-0.48, p<0.007), plasma vitamin C levels (r=-0.53, p<0.003 and r=-0.44, p<0.02), erythrocyte activity of antioxidant enzymes, and erythrocyte GSH/GSSG ratio, with hypertensives showing higher levels of oxidative stress. Blood pressures showed a positive correlation with both plasma and urine 8-isoprostane. Neither plasma vitamin E nor the assessed blood pressure modulator levels showed significant differences between the groups or correlation with blood pressures. These findings demonstrate a strong association between blood pressure and some oxidative stress-related parameters and suggest a possible role of oxidative stress in the pathophysiology of essential hypertension.     

Challenges in accessing multidisciplinary pain treatment facilities in Canada

PURPOSE: The objective of this survey was to examine the services offered by multidisciplinary pain treatment facilities (MPTFs) across Canada and to compare access to care at these MPTFs. METHODS: A MPTF was defined as a clinic that advertised specialized multidisciplinary services for the diagnosis and management of patients with chronic pain, having a minimum of three different health care disciplines (including at least one medical speciality) available and integrated within the facility. The search method included approaching all hospital and rehabilitation centre administrators in Canada, the Insurance Bureau of Canada, the Workplace Safety and Insurance Board or similar body in each province. Designated investigators were responsible for confirming and supplementing MPTFs from the preliminary list for each province. Administrative leads at each eligible MPTF were asked to complete a detailed questionnaire regarding their MPTF infrastructure, clinical, research, teaching and administrative activities. RESULTS: Completed survey forms were received from 102 MPTFs (response rate 85%) with 80% concentrated in major cities, and none in Prince Edward Island and the Territories. The MPTFs offer a wide variety of treatments including non-pharmacological modalities such as interventional, physical and psychological therapy. The median wait time for a first appointment in public MPTFs is six months, which is approximately 12 times longer than non-public MPTFs. Eighteen pain fellowship programs exist in Canadian MPTFs and 64% engage in some form of research activities CONCLUSION: Canadian MPTFs are unable to meet clinical demands of patients suffering from chronic pain, both in terms of regional accessibility and reasonable wait time for patients' first appointment.     

In vitro release of lectins by Phallusia mamillata hemocytes.

-Lactose specific lectins are released from Phallusia mamillata hemocytes during short-term cultures. The molecular weight of the subunits, the immunological cross-reaction and the sugar specificity suggest that the released lectins are similar to those isolated from the sonicated hemocytes. Because lectin release appears to take place independently of active protein synthesis, the possibility exists that lectins are pre-formed, stored in hemocytes and released when in vitro conditions stimulate the cells.     

APOE epsilon3 gene transfer attenuates brain damage after experimental stroke.

Apolipoprotein E (apoE, protein; APOE, gene) is the major lipid-transport protein in the brain and plays an important role in modulating the outcome and regenerative processes after acute brain injury. The aim of the present study was to determine if gene transfer of the epsilon3 form of APOE improves outcome in a murine model of transient focal cerebral ischaemia. Mice received an intrastriatal injection of vehicle, a second-generation adenoviral vector containing the green fluorescent protein gene (Ad-GFP) or a vector containing the APOE epsilon3 gene (Ad-APOE) 3 days before 60 mins focal ischaemia. Green fluorescent protein expression was observed in cells throughout the striatum and subcortical white matter indicating successful gene transfer and expression. ApoE levels in the brain were significantly increased after Ad-APOE compared with Ad-GFP or vehicle treatment. Ad-APOE treatment reduced the volume of ischaemic damage by 50% compared with Ad-GFP or vehicle treatment (13+/-3 versus 29+/-4 versus 27+/-5 mm(3)). The extent of postischaemic apoE immunoreactivity was enhanced in Ad-APOE compared with Ad-GFP or vehicle treated mice. These results show the ability of APOE gene transfer to markedly improve outcome after cerebral ischaemia and suggest that modulating apoE levels may be a potential strategy in human stroke therapy.     

Postangioplasty renal artery thrombosis treated intraluminally with thrombolysis. A case report]

The authors present the clinical case of a 31 year female with systemic vascular hypertension secondary to a 65 percent unilateral fibromuscular renal artery stenosis. The centellographic study demonstrated hypoperfusion on the right kidney and serious functional damage; the patient was subject to intraluminal renal angioplasty resulting in right renal arterial thrombosis, which was treated successfully with intra-arterial and intravenous streptokinase infusion. Following the thrombotic therapy, recanalization of the thrombosed artery and normal renal excretion of the contrast substance was observed.