Locus Coeruleus magnetic resonance imaging: a comparison between native-space and template-space approach.

Locus Coeruleus (LC) is the main noradrenergic nucleus of the brain, which is involved in many physiological functions including cognition; its impairment may be crucial in the neurobiology of a variety of brain diseases. Locus Coeruleus-Magnetic Resonance Imaging (LC-MRI) allows to identify in vivo LC in humans. Thus, a variety of research teams have been using LC-MRI to estimate LC integrity in normal aging and in patients affected by neurodegenerative disorders, where LC integrity my work as a biomarker. A number of variations between LC-MRI studies exist, concerning post-acquisition analysis and whether this had been performed within MRI native space or in ad hoc-built MRI template space. Moreover, the reproducibility and reliability of this tool is still to be explored. Therefore, in the present study, we analyzed a group of neurologically healthy, cognitively intact elderly subjects, using both a native space- and a template space-based LC-MRI analysis. We found a good inter-method agreement, particularly considering the LC Contrast Ratio. The template space-based approach provided a higher spatial resolution, lower operator-dependency, and allowed the analysis of LC topography. Our ad hoc-developed LC template showed LC morphological data that were in line with templates published very recently. Remarkably, present data significantly overlapped with a recently published LC "metaMask", that had been obtained by averaging the results of a variety of previous LC-MRI studies. Thus, such a template space-based approach may pave the way to a standardized LC-MRI analysis and to be used in future clinic-anatomical correlations.

Application of Monte Carlo Algorithms to Cardiac Imaging Reconstruction.

Monte Carlo algorithms have a growing impact on nuclear medicine reconstruction processes. One of the main limitations of myocardial perfusion imaging (MPI) is the effective mitigation of the scattering component, which is particularly challenging in Single Photon Emission Computed Tomography (SPECT). In SPECT, no timing information can be retrieved to locate the primary source photons. Monte Carlo methods allow an event-by-event simulation of the scattering kinematics, which can be incorporated into a model of the imaging system response. This approach was adopted in the late Nineties by several authors, and recently took advantage of the increased computational power made available by high-performance CPUs and GPUs. These recent developments enable a fast image reconstruction with improved image quality, compared to deterministic approaches. Deterministic approaches are based on energy-windowing of the detector response, and on the cumulative estimate and subtraction of the scattering component. In this paper, we review the main strategies and algorithms to correct the scattering effect in SPECT and focus on Monte Carlo developments, which nowadays allow the threedimensional reconstruction of SPECT cardiac images in a few seconds.

Associations between common carotid artery diameter, Framingham risk score and cardiovascular events.

BACKGROUND AND AIMS: Vascular biomarkers are associated with risk burden and are capable to predict the development of future cardiovascular (CV) events; yet, their additive predictive value over and above established risk algorithms seems to be only modest. The present study evaluated the cross-sectional associations between vascular biomarkers, 10-year Framingham risk (FR) and prevalent CV events in a population with a high prevalence of hypertension and diabetes. METHODS AND RESULTS: As many as 681 subjects (419 men, age = 60 ± 10 years, 282 diabetics, 335 hypertensives, mean FR score = 22.5 ± 16.5%) underwent an integrated vascular examination including: radiofrequency-based ultrasound of common carotid artery (cca) to measure intima-media thickness (IMT), inter-adventitial diameter (IAD) and local pulse wave velocity (PWV); applanation tonometry to assess carotid pulse pressure (PP) and augmentation index (AIx); carotid-femoral PWV (cfPWV) measurement. One hundred and thirty-five subjects (19.8%) had history of CV events, and CV events were independently associated with male sex, age, antihypertensive treatment, current smoking, HDL-cholesterol and ccaIAD. In logistic regression model, only ccaIAD was associated with prevalence of CV events after adjustment for FR score, with the OR of 1.71 [1.34-2.19] (P < 0.0001) that remained unchanged when ccaIMT was included into the model (OR = 1.76 [1.36-2.27]; P < 0.0001). The association between prevalent CV events and ccaIAD was significant (OR of 1.65 [1.24-2.20]; P = 0.0005) also in a subgroup of subjects being at a high 10-year risk of CV disease (N = 330). CONCLUSIONS: In a population with a high prevalence of diabetes and hypertension, ccaIAD was the only vascular measure associated with prevalent CV events, independently of FR score.

Single cell analysis of cancer cells using an improved RT-MLPA method has potential for cancer diagnosis and monitoring.

Single cell analysis techniques have great potential in the cancer genomics field. The detection and characterization of circulating tumour cells are important for identifying metastatic disease at an early stage and monitoring it. This protocol is based on transcript profiling using Reverse Transcriptase Multiplex Ligation-dependent Probe Amplification (RT-MLPA), which is a specific method for simultaneous detection of multiple mRNA transcripts. Because of the small amount of (circulating) tumour cells, a pre-amplification reaction is performed after reverse transcription to generate a sufficient number of target molecules for the MLPA reaction. We designed a highly sensitive method for detecting and quantifying a panel of seven genes whose expression patterns are associated with breast cancer, and optimized the method for single cell analysis. For detection we used a fluorescence-dependent semi-quantitative method involving hybridization of unique barcodes to an array. We evaluated the method using three human breast cancer cell lines and identified specific gene expression profiles for each line. Furthermore, we applied the method to single cells and confirmed the heterogeneity of a cell population. Successful gene detection from cancer cells in human blood from metastatic breast cancer patients supports the use of RT-MLPA as a diagnostic tool for cancer genomics.

Diagnostic accuracy of MDCT coronary angiography in patients referred for heart valve surgery.

PURPOSE: The aim of our study was to evaluate the role of multidetector-row computed tomography (MDCT) in patients referred for heart valve surgery. We studied the diagnostic performance of CT coronary angiography (CTCA) compared with conventional coronary angiography (CCA) before valve surgery. MATERIALS AND METHODS: During a 13-month period, 55 consecutive patients under evaluation for aortic (40/55) or mitral valve (15/55) disease before potential valve replacement underwent CTCA using a 64-detector-row scanner within 2 months of CCA for comparative purposes. All 17 major coronary artery segments were evaluated by one observer and compared with the reference standard. Patient-based, vessel-based and segment-based analyses of the data were performed. RESULTS: Prevalence of significant coronary artery disease, defined as having at least one stenosis >/=50% per patient, was 36%. On a patient-based analysis, sensitivity, specificity and positive and negative predictive values were 100%, 91%, 83% and 100%, respectively. CONCLUSIONS: The diagnostic accuracy of 64-row CTCA for ruling out the presence of significant coronary stenoses in patients undergoing valve surgery is excellent and allows CTCA to be used as a gatekeeper for invasive CCA in these patients. MDCT is a necessary preoperative examination that provides useful information for identifying potential operative complications of surgical procedures.

Electrochemical quantification of DNA amplicons via the detection of non-hybridised guanine bases on low-density electrode arrays.

A new strategy for the electrochemical detection and signal amplification of DNA at gold electrodes is described. Current methodologies for DNA biosensing based on the electrochemical detection of electroactive base-specific labels such as methylene blue (MB) suffer from lengthy incubation and washing steps. Addressing these limitations, we report a novel approach for the electrochemical quantification of surface hybrid, using the control gene LTA, 107 bases long, as a model target. An array of 15 gold electrodes was used to detect the formation of hybridised duplex following interaction of non-hybridised guanine bases with MB present in solution. Upon hybridisation the number of free guanines present at the electrode surface increased from 8 to 25 due to guanine bases present in the target sequence which did not participate in hybridisation and remained free to interact directly with methylene blue. This increase in free guanines consequently concentrated MB directly at the electrode surface. We found that the MB signal recorded for 100 nM of the complementary LTA was typically 2.14 times higher than that of the non-hybridised state. Very low cross-reactivity (<7%) with a non-complementary probe was recorded. The assay was optimised with regards to methylene blue concentration, hybridisation time and regeneration. The assay was quantitative and linear in the range of 6.25-50 nM target DNA exhibiting an LOD of 17.5 nM. The assay was rapid and easy to perform, with no need for lengthy incubations with the methylene blue label or requirement for washing steps. Ongoing work addresses the impact of guanine location on the signal in order to tailor design specific signalling domains of PCR products.

Mycobacterial skeletal infection of the foot. A case report.

Peripheral skeletal infections caused by Mycobacterium are widely reported in the literature. Unfamiliarity with this disease, or oversight caused by inexperience may result in failure to thoroughly investigate the presence of this organism. An unusual case of tuberculous osteomyelitis involving the second digit of the foot is presented. The authors emphasize the importance of including cultures of acid-fast bacillus in the work-up of atypical infectious processes of the foot and ankle, and include Mycobacterium in their differential until it is positively ruled out. An in-depth radiologic review is included.

Pharmacokinetics and bioavailability of medroxyprogesterone acetate in the dog and the rat.

Medroxyprogesterone acetate (MPA) has been administered to rats and dogs. Dogs received single oral doses of 2.5, 5, and 10 mg MPA and a single intravenous dose of 1 mg MPA. Rats received single oral doses of 0.2, 1, 5, and 20 mg kg-1 MPA and multiple oral doses (14 daily doses) of 0.2, 5, and 20 mg kg-1 MPA. Dog plasma MPA levels from the intravenous dose were characterized by a triexponential decay with disposition half-lives of 0.3, 1.8, and 21.6 h. A Loo-Riegelman analysis of the dog plasma MPA levels from oral doses indicated absorption was not a simple first-order process. The Weibull Function was used to characterize the absorption kinetics of MPA. The oral absorption of MPA in dogs appears to be dose-linear over the dosage range studied, and the absolute bioavailability was estimated at 27 per cent. Rat plasma MPA levels from single and multiple oral doses were analyzed by a non-compartmental approach. AUC and Cmax values were not dose-linear over the dosage range studied; indicative of the self-induced metabolism of MPA. Exposure of similar dosages of MPA to both the rat and the dog resulted in similar plasma profiles and pharmacokinetics.

Mequitazine in the treatment of hayfever.

A single-blind, multicentre, comparative clinical trial was performed in 59 hayfever sufferers to compare the efficacy of mequitazine 5 mg bd and terfenadine 60 mg bd over a period of 14 days. Clinical assessments of nasal and ocular symptoms were made on admission to the trial and after seven and 14 days treatment by both physicians and patients. Critical flicker fusion threshold was measured at each assessment. A global assessment of efficacy was determined by both the doctor and patient at the end of treatment. Patients also completed a daily diary card. Thirty patients on mequitazine and 22 on terfenadine completed the trial. There were seven dropouts (five on terfenadine and two on mequitazine). Both treatments were equally effective in reducing the severity of symptoms over the 14 days of treatment. The overall assessment at the end of treatment showed no important significant differences between the two drugs. According to the physicians, 60 per cent of the mequitazine-treated patients and 63 per cent of the terfenadine-treated patients had an excellent or good response. Patients assessed their response as excellent or good in 56 and 62 per cent of cases respectively. Neither drug significantly impaired performance.

An open, randomized comparative study of a low-strength frusemide/amiloride combination and bumetanide/potassium chloride in the treatment of mild congestive cardiac failure.

In an open, randomized, parallel group study lasting 8 weeks, nine males and nine females with mild congestive cardiac failure were initially treated daily with 20 mg frusemide/2.5 mg amiloride or 0.5 mg bumetanide/573 mg potassium chloride. In two patients receiving the frusemide combination and in one receiving the bumetanide combination, the daily dose was doubled after 2 weeks' treatment because of inadequate control of symptoms. Mild congestive cardiac failure symptoms (raised jugular venous pressure, oedema and dyspnoea at rest and on effort) were controlled in 9/10 patients receiving frusemide/amiloride but two patients receiving bumetanide/potassium chloride still had mild oedema after 8 weeks. Both treatments were well tolerated overall and there were no clinically significant changes in plasma electrolytes, although one patient treated with frusemide/amiloride was withdrawn due to adverse events.

Effect of nickel(II) on DNA-protein interactions.

Alterations in DNA-protein interactions (DPI) may play an important role in carcinogenesis. Although the mechanism of nickel carcinogenesis is unknown, nickel reportedly affects DPI. A microfiltration, nitrocellulose filter assay was utilized to study DPI in intact Chinese hamster ovary (CHO) cells and in isolated nuclei. Prior to exposure of CHO cells or isolated CHO cell nuclei, DNA and proteins were radiolabeled using 3H-thymidine and 35S-methionine, respectively. Nuclei were exposed to NiCl2 in 10 mM HEPES buffer (pH 6.8). CHO cells were exposed in either complete or a salts-glucose medium. Following exposure, nuclei or cells were incubated at 37 degrees C for 20 min in a high salt lysis solution; aliquots were loaded onto nitrocellulose filters and washed with a low salt solution. DNA (3H) retained on each filter was normalized to protein (35S) bound on the filter. Exposure of either whole cells or isolated nuclei to increasing, noncytotoxic concentrations of NiCl2 resulted in a dose dependent decrease in DPI. The effect of nickel on specific DNA-protein interactions was examined using a band shift assay and a cloned satellite DNA sequence. Nickel inhibited specific protein binding to the satellite DNA probe. The results of these two independent assays, which were conducted at physiological pH, indicate that NiCl2 inhibits specific DNA-protein interactions.

A multi-centre, placebo controlled comparative study between 200 mg and 400 mg celiprolol in patients with mild to moderate essential hypertension.

A two-centre, double-blind, placebo controlled, randomized 3-way crossover study was undertaken to assess the efficacy, tolerability and safety of celiprolol in mild to moderate essential hypertension. A 4-week single-blind placebo run-in/screening period, during which no antihypertensive medication was given, was followed by 3 consecutive 4-week treatment periods with placebo or celiprolol (200 mg or 400 mg daily). At the end of the 4-week placebo run-in/screening period, 26 hospital out-patients with a seated mean blood pressure (systolic/diastolic) of 161.4/101.7 mmHg and a mean pulse rate of 75 beats/min entered the double-blind crossover phase of the study. Results showed that there was no significant difference in seated mean systolic or diastolic blood pressure between 200 mg celiprolol daily (149.2/92.3 mmHg) and 400 mg celiprolol daily (149.1/92.5 mmHg). However, mean seated systolic and diastolic blood pressures were significantly (p less than 0.05) lower on celiprolol than on placebo (157.1/98.2 mmHg). Neither dose of celiprolol had a significant effect on seated pulse rate. No patient was withdrawn due to an adverse event and no laboratory assessment outside the normal range was reported to be of any clinical significance. It is concluded that oral celiprolol, 200 mg or 400 mg daily, is effective and well tolerated for controlling mild to moderate essential hypertension. Since both doses had very similar effects on blood pressure there is no advantage in this group of patients for the 400 mg daily dose of celiprolol.

Toxicity and carcinogenicity of nickel compounds.

The toxicity and carcinogenicity of nickel compounds are considered in three broad categories: (1) systemic toxicology, (2) molecular toxicology, and (3) carcinogenicity. The systemic toxicity of nickel compounds is examined based upon human and animal studies. The major organs affected are discussed in three categories: (1) kidney, (2) immune system, and (3) other organs. The second area of concentration is molecular toxicology, which will include a discussion of the chemistry of nickel, its binding to small and large molecular weight ligands, and, finally, its cellular effects. The third major area involves a discussion of the carcinogenicity and genotoxicity of nickel compounds. This section focuses on mechanisms, using studies conducted in vivo and in vitro. It also includes a discussion of the assessment of the carcinogenicity of nickel compounds.

A comparison of felodipine and propranolol as additions to hydrochlorothiazide in the treatment of hypertension.

Eighty one patients with uncomplicated hypertension who required additional antihypertensive medication (diastolic Phase V [dBP] greater than or equal to 95 mm Hg) after 4 weeks treatment with hydrochlorothiazide (HCTZ) 25 mg o.m. were randomized to receive felodipine 5 mg b.i.d. (n = 40) or propranolol (n = 41) 80 mg b.i.d. in addition to HCTZ 25 mg o.m. If the dBP measured about 12 h post-dose was not less than or equal to 90 mm Hg after 4 weeks, the dose of felodipine or propranolol was doubled. The double blind trial period was 8 weeks for all patients. Over the 8 week period, felodipine reduced the seated dBP from 100 to 83 mm Hg and propranolol from 101 to 86 mm Hg. The attained seated dBPs were significantly different in the two groups. About one third of patients in each group received the high dose of second-line therapy. After 8 weeks 91% of patients receiving HCTZ+felodipine and 84% receiving HCTZ+propranolol had a dBP less than or equal to 90 mm Hg. Both regimens were well-tolerated with an equal incidence but different pattern of adverse events (felodipine: flushing, headache and peripheral oedema; propranolol: dyspepsia, fatigue and vasospasm). In this 8-week study, felodipine and propranolol were safe and effective second-line antihypertensive drugs when added to hydrochlorothiazide. At the doses selected, felodipine was at least as effective as propranolol.

Lead toxicity in chicks: interactions with dietary methionine and choline.

Two factorial experiments were conducted to study the effects of dietary methionine and choline on lead toxicity in chicks. Dietary variables were 0.3 or 0.63% (experiment 1) or 0.23 or 0.75% methionine (experiment 2); 0 or 1000 ppm lead (as Pb acetate X 3H2O); and 1130 or 3300 mg/kg (experiment 1) or 396 or 1266 mg/kg choline (experiment 2). In both experiments, lead depressed growth while methionine stimulated growth. Growth depression by lead was less with methionine-adequate than with methionine-inadequate diets. There were no differences in growth with the choline-marginal or choline-excess diets. In experiment 2, the methionine x lead interaction for growth was observed with choline-adequate but not with choline-inadequate diets. Lead-induced depression of growth was exacerbated by added choline when methionine-inadequate diets were fed. With methionine-adequate diets, choline level had no effect on the lead-induced depression of growth. Hepatic nonprotein sulfhydryl (NPSH) concentrations were increased by both supplemental methionine and lead with no interaction. Choline levels had no effect on NPSH. Dietary methionine significantly lowered Pb concentration of kidney and muscle but not of bone, liver or blood. Choline had no effect on organ Pb concentrations. Methionine, either dietary or in the dosing solution, had no effect on in situ intestinal absorption or 203PbCl2. These results suggest that lead lowers the chick's choline requirement and that the methyl moiety of methionine does not participate directly in lead detoxication. The amelioration of Pb toxicity by methionine appears to be related to increased excretion of Pb.

Modification of lead toxicity and organ distribution by dietary sulfur amino acids in chicks (Gallus domesticus).

Chicks (Gallus domesticus) were fed a basal diet deficient in methionine and total sulfur amino acids with 0 or 1000 ppm added lead for 21 days. Methionine or methionine and cystine addition improved growth regardless of dietary lead level. Cystine addition alone improved growth only when lead was present. Relative inhibition of growth by lead was greater with diets containing no added methionine. Hepatic non-protein sulfhydryl concentration was increased by lead and all amino acid additions. Organ lead concentrations were generally lower with added amino acids. Dietary methionine appears to counteract lead toxicity more effectively than cystine.

[The effects of dietary methionine and glycine on lead toxicity in choline-deficient chicks].

A 2×2×2 factorial experiment was conducted to study the effects of dietary methionine, glycine, and lead (Pb) in cholinedeficient chicks. The variables were: adequate or deficient methionine; adequate or excess glycine; and 0 or 1000 ppm lead (as Pb acetate 3H2O). Methionine stimulated growth when added to the methionine-deficient diets, but the response was greater when supplemental glycine was present. Addition of glycine to the glycine-adequate diets stimulated growth in the presence of adequate but not deficient methionine. The patterns of response to methionine were the same at both 0 and 1000 ppm dietary Pb. Added Pb depressed growth with all diets, but the depression was greater in methionine-deficient than in methionine-adequate diets. Hepatic nonprotein sulfhydryl (NPSH) and glutathione (GSH) concentrations were increased by both supplemental methionine and lead, and the effects were additive. Glycine levels did not significantly alter NPSH and GSH concentrations. Both methionine and glycine lowered Pb concentrations in kidney, and the effects were additive. The results are consistent with previous observations that added methionine ameliorates Pb-induced growth depression with choline-adequate diets, however, this effect is not as pronounced with choline-deficient diets. The results suggest (1) that glycine is limiting for growth in choline-deficient, methionine-adequate diets, and (2) that methionine and glycine may enhance Pb detoxification by different mechanisms.