Free thyroid hormones in serum by direct equilibrium dialysis and online solid-phase extraction--liquid chromatography/tandem mass spectrometry

BACKGROUND: Measurements of free thyroxine (FT4) and free triiodothyronine (FT3) are important for the diagnosis and monitoring of thyroid diseases. Considerable differences among methods limit their clinical utility, however, and accurate methods are needed for various clinical specimens. We describe a direct equilibrium dialysis (ED)-liquid chromatography (LC)/tandem mass spectrometry (MS/MS) method for FT4 and FT3. METHODS: ED was selected as the separation step. Serum samples were dialyzed 1:1 against a simple protein-free buffer for 20 h at 37 degrees C. Thyroid hormones in dialysates were purified by online solid-phase extraction (SPE), then chromatographically separated and quantified in positive ion and multiple reaction monitoring modes. RESULTS: For FT4 and FT3, the lower and upper limits of quantification were 1 ng/L (pg/mL) and 400 ng/L with total imprecision <10%. The method correlated well with an ED-RIA, 2 direct immunoassay methods for FT4, and 1 direct immunoassay and 1 tracer dialysis method for FT3. The adult reference intervals were 12.8-22.2 ng/L for FT4 and 3.62-6.75 ng/L for FT3. Reference intervals for the second trimester of pregnancy (14-20 weeks of gestation) were also established. CONCLUSIONS: We developed a simple protein-free buffer and ED procedure. The performance characteristics and high throughput of the LC-MS/MS method with online SPE for FT4 and FT3 (also reverse T3) are sufficient for the intended clinical use.     

Assessing the impact of upper limb disability following stroke: a qualitative enquiry using internet-based personal accounts of stroke survivors

Purpose: Upper limb disability following stroke may have multiple effects on the individual. Existing assessment instruments tend to focus on impairment and function and may miss other changes that are personally important. This study aimed to identify personally significant impacts of upper limb disability following stroke. Methods: Accounts by stroke survivors, in the form of web-based diaries (blogs) and stories, were sought using a blog search engine and in stroke-related web-sites. Thematic analysis using the World Health Organisation’s International Classification of Functioning Disability and Health (ICF) was used to identify personal impacts of upper limb disability following stroke. Results: Ninety-nine sources from at least four countries were analysed. Many impacts were classifiable using the ICF, but a number of additional themes emerged, including emotional, cognitive and behavioural changes. Blogs and other web-based accounts were easily accessible and rich sources of data, although using them raised several methodological issues, including potential sample bias. Conclusions: A range of impacts was identified, some of which (such as use of information technology and alienation from the upper limb) are not addressed in current assessment instruments. They should be considered in post-stroke assessments. Blogs may help in the development of more comprehensive assessments.

• Implications for Rehabilitation

• A comprehensive assessment of the upper limb following stroke should include the impact of upper limb problems on social participation, as well as associated emotional, cognitive and behavioural changes.

• Using personalised assessment instruments alongside standardised measures may help ensure that these broader domains are considered in discussions between clinicians and patients.

• Rehabilitation researchers should investigate whether and how these domains could be addressed and operationalised in standard upper limb assessment instruments.

     

Modification of the cardiovascular effects of l-dopa by decarboxylase inhibitors

Intravenously infused L-dopa (0.3 mg/kg per min) produced hypertension and cardiac arrhythmias in halothane anesthetized dogs. Biochemical studies showed that the heart, kidney, and brain of these animals accumulated significant amounts of catecholamines formed from the administered precursor.Pretreatment of dogs with an extracerebral inhibitor of dopa decarboxylase [D,L-alpha-hydrazino-alpha-methyl-beta-(3.4-dihydroxyphenyl) propionic acid] prevented the development of hypertension and arrhythmias with infusion of L-dopa. Instead, these animals developed significant hypotension. The heart and kidney of these animals accumulated markedly reduced amounts of catecholamines formed from L-dopa compared with dogs receiving L-dopa alone: the amount of catecholamines accumulated in brain was unchanged. L-dopa, after extracerebral decarboxylase inhibition, appeared to produce hypotension by reducing peripheral vascular resistance without altering sympathetic nerve function. During hypotension, cardiac output was not altered and arterial pressure in perfused hindlimbs fell, even though flow was maintained. The pressor response to intravenous injections of norepinephrine and dopamine was unchanged. Hindlimb arterial pressure response to direct electrical stimulation of the lumbar sympathetic trunk was also unchanged.Pretreatment with a drug which inhibits brain as well as extracerebral dopa decarboxylase [D,L-seryl-2,3,4-trihydroxybenzylhydrazine hydrochloride] abolished all effects of L-dopa on blood pressure. In these animals, there was a marked reduction of catecholamine formation from L-dopa in the brain as well as the heart and kidney.It appears that L-dopa produces opposite effects on blood pressure depending on the site of accumulation of its metabolic products, dopamine and norepinephrine. If L-dopa is rapidly decarboxylated to catecholamines in peripheral organs, hypertension and cardiac arrhythmias occur. If peripheral dopa decarboxylase is selectively inhibited, a centrally mediated hypotensive effect, probably secondary to the accumulation of catecholamines in the brain, becomes apparent. If dopa decarboxylase is inhibited in the brain in addition to extracerebral organs, L-dopa has no effect on blood pressure.     

Prevention and chemoprevention of colorectal neoplasms

Main purpose of the review is to analyse the impact of the current approaches for colorectal cancer prevention, including chemoprevention. Available evidence does not support the contention that a more appropriate diet can be of great help in the prevention of these neoplasms, either because the scientific evidence is poor and highly controversial, or because changes in diet are difficult to implement, at least in many Western countries. Similarly, a preventive approach based on the modification of lifestyle remains improbable, either in the short --or in the long period of time. Secondary prevention--i.e., the systematic removal of adenomatous polyps--can hardly be applied in the general population, with the exception of individuals at risk because members of families with Adenomatosis coli or Lynch syndrome, or affected by inflammatory bowel diseases. Finally, chemoprevention (i.e., the attempt to prevent tumour development through the administration of drugs or natural compounds that interfere with various phases of carcinogenesis) is still in its infancy Though attractive, this approach requires well-designed studies which should be carried out for years before being evaluated and interpreted; so far most of these investigations gave inconsistent or controversial results. In conclusion, both primary and secondary prevention of colorectal malignancies appear difficult to apply in the general population, and chemoprevention is still at the beginning of a (presumably] long story. The final impression is that notwithstanding the remarkable advancements made in the last two decades in colorectal cancer research, the practical application of these new concepts remains difficult.     

Role of the endothelium in modulating neointimal formation: vasculoprotective approaches to attenuate restenosis after percutaneous coronary interventions

Restenosis at the site of an endoluminal procedure remains a significant problem in the practice of interventional cardiology. We present current data on intimal hyperplasia, which identify the major role of endothelial cells (ECs) in the development of restenosis. Considering endothelial denudation as one of the most important mechanisms contributing to restenosis, we focus more attention on methods of accelerating restoration of endothelial continuity. Prevention of restenosis may be achieved by promoting endothelial regeneration through the use of growth factors, EC seeding, vessel reconstruction with autologous EC/fibrin matrix, and the use of estrogen-loaded stents and stents designed to capture progenitor ECs.     

Risk factors of vascular complications in patients at a predialysis stage of chronic renal failure

AIM: To specify risk factors of vascular complications at a predialysis stage of renal failure. MATERIAL AND METHODS: The trial enrolled 165 patients with chronic renal failure (CRF) aged 46 +/- 15 years, glomerular filtration rate (GFR) - 37.2 (35.02-40.83) and arterial hypertension (96%). The examination included ultrasound dopplerography of the common carotid arteries (CCA) and common femoral arteries (CFA) for detection of atherosclerotic plaques (AP), estimation of the thickness of arterial intima-media, elasticity and rigidity of the vascular wall. Factors of risk for atherosclerosis and cardiovascular complications were assessed. RESULTS: Aortic atherosclerosis was detected in 60 patients, that of cardiac vessels, brain, kidneys and lower limbs - in 35, 30, 23 and 8 patients, respectively. Acute cardiovascular complications occurred in 13 patients. Main atherosclerosis risk factors were age, body mass index, systolic and pulse arterial pressure, disturbances of phosphorus-calcium metabolism. Structure and function of CCA and CFA were studied with dopplerography in 37 CRF patients. Increased intima-media thickness was associated with age, male sex, overweight, hypercholesterinemia, systolic and pulse arterial pressure. Body mass index, GFR, creatinin level were independent factors of intima-media thickness. Abnormal elasticity of CCA was related to hypertension, CFA - to hypercholesterolemia.