Whole mitochondrial genome sequencing highlights mitochondrial impact in gastric cancer.

Mitochondria are organelles that perform major roles in cellular operation. Thus, alterations in mitochondrial genome (mtGenome) may lead to mitochondrial dysfunction and cellular deregulation, influencing carcinogenesis. Gastric cancer (GC) is one of the most incident and mortal types of cancer in Brazil, particularly in the Amazon region. Here, we sequenced and compared the whole mtGenome extracted from FFPE tissue samples of GC patients (tumor and internal control - IC) and cancer-free individuals (external control - EC) from this region. We found 3-fold more variants and up to 9-fold more heteroplasmic regions in tumor when compared to paired IC samples. Moreover, tumor presented more heteroplasmic variants when compared to EC, while IC and EC showed no significant difference when compared to each other. Tumor also presented substantially more variants in the following regions: MT-RNR1, MT-ND5, MT-ND4, MT-ND2, MT-DLOOP1 and MT-CO1. In addition, our haplogroup results indicate an association of Native American ancestry (particularly haplogroup C) to gastric cancer development. To the best of our knowledge, this is the first study to sequence the whole mtGenome from FFPE samples and to apply mtGenome analysis in association to GC in Brazil.

Beyond the blocking model to fit nanoparticle ZFC/FC magnetisation curves.

We consider the probability of a magnetic nanoparticle to flip its magnetisation near the blocking temperature, and use this to develop quasi-analytic expressions for the zero-field-cooled and field-cooled magnetisation, which go beyond the usual critical energy barrier approach to the superparamagnetic transition. The particles in the assembly are assumed to have random alignment of easy axes, and to not interact. We consider all particles to be of the same size and then extend the theory to treat polydisperse systems of particles. In particular, we find that the mode blocking temperature is at a lower temperature than the peak in the zero-field-cooled magnetisation versus temperature curve, in agreement with experiment and previous rate-equation simulations, but in contrast to the assumption many researchers use to analyse experimental data. We show that the quasi-analytic expressions agree with Monte Carlo simulation results but have the advantage of being very quick to use to fit data. We also give an example of fitting experimental data and extracting the anisotropy energy density K.

Development of Ferrite-Based Temperature Sensors for Magnetic Resonance Imaging: A Study of Cu1-xZnxFe2O4.

We investigate the use of Cu1-x Zn x Fe2O4 ferrites (0.60 < x < 0.76) as potential sensors for magnetic- resonance-imaging thermometry. Samples are prepared by a standard ceramic technique. Their structural and magnetic properties are determined using x-ray diffraction, scanning electron microscopy, super-conducting quantum-interference device magnetometry, and Mossbauer and 3-T nuclear-magnetic-resonance spectroscopies. We use the mass magnetization of powdered ferrites and transverse relaxivity r*2 of water protons in Ringer's-solution-based agar gels with embedded micron-sized particles to determine the best composition for magnetic-resonance-imaging (MRI) temperature sensors in the (280-323)-K range. A preclinical 3-T MRI scanner is employed to acquire T*2 weighted temperature-dependent images. The brightness of the MRI images is cross-correlated with the temperature of the phantoms, which allows for a temperature determination with approximately 1°C accuracy. We determine that the composition of 0.65 < x < 0.70 is the most suitable for MRI thermometry near human body temperature.

Ferromagnetic particles as magnetic resonance imaging temperature sensors.

Magnetic resonance imaging is an important technique for identifying different types of tissues in a body or spatial information about composite materials. Because temperature is a fundamental parameter reflecting the biological status of the body and individual tissues, it would be helpful to have temperature maps superimposed on spatial maps. Here we show that small ferromagnetic particles with a strong temperature-dependent magnetization, can be used to produce temperature-dependent images in magnetic resonance imaging with an accuracy of about 1 °C. This technique, when further developed, could be used to identify inflammation or tumours, or to obtain spatial maps of temperature in various medical interventional procedures such as hyperthermia and thermal ablation. This method could also be used to determine temperature profiles inside nonmetallic composite materials.

High-frequency spectral changes in Dorsolateral Prefrontal Cortex for potential neuoroprosthetics.

Dorsolateral Prefrontal Cortex (DLPFC) has been associated with goal encoding in primates. Thus far, the majority of research involving DLPFC, including all electrophysiology studies, has been performed in non-human primates. In this paper, we explore the possibility of utilizing the cortical activity in DLPFC in humans for use in Brain-Computer Interfaces (BCIs). Electrocorticographic signals were recorded from seven patients with intractable epilepsy who had electrode coverage over DLPFC. These subjects performed a visuomotor target-based task to assess DLPFC's involvement in planning, execution, and accomplishment of the simple motor task. These findings demonstrate that there is a distinct high-frequency spectral component in DLPFC associated with accomplishment of the task. It is envisioned that these signals could potentially provide a novel verification of task accomplishment for a BCI.

Development and Validation of a Real-Time PCR Assay for the Quantification of Verticillium dahliae in Potato.

An increase in the stringency for higher quality potato tubers and restrictions on the use of soil fumigants, among other factors, has garnered renewed interest in Verticillium wilt, particularly in russet-skinned cultivars grown for processing. In response to the needs of producers, breeders have increased efforts in the development of potato cultivars with resistance to Verticillium dahliae Kleb., the primary cause of Verticillium wilt. These efforts have resulted in the release of numerous russet-skinned cultivars with purported resistance to the pathogen. However, because efficient and effective methods to screen germplasm for true resistance do not exist, breeders typically have reported resistance based on the development of wilt symptoms alone. The studies reported here demonstrate the efficiency and practicality of a QPCR method for quantification of V. dahliae in potato stem tissue. This method, developed to detect the target trypsin protease gene of the pathogen, was compared with traditional methods for V. dahliae quantification which involve plating stem tissue or sap onto semi-selective media, as well as to a recently developed QPCR assay which amplifies a region of the ß-tubulin gene of V. dahliae. The QPCR assay developed in the studies reported here was demonstrated to be sensitive to 0.25 pg of DNA. Use of the duplex real-time PCR assay, utilizing the potato actin gene to normalize quantification, resulted in clearer differentiation of levels of resistance among eight russet-skinned potato cultivars inoculated in greenhouse trials when compared with traditional plating assays. However, relative levels of resistance among cultivars were similar between traditional plating and QPCR methods, resulting in correlation coefficients greater than 0.93. The assay described here also detected the pathogen in inoculated stem tissue at higher frequencies than both traditional plating assays and a previously developed QPCR assay. The QPCR assay developed here demonstrates rapid, efficient, and accurate quantification of V. dahliae, providing a tool amenable for use by breeding programs on large numbers of clones and selections, and will aid researchers evaluating other control strategies for Verticillium wilt.

Electrocorticographic frequency alteration mapping of speech cortex during an awake craniotomy: case report.

OBJECTIVE: Traditional electrocortical stimulation (ECS) mapping is limited by the lengthy serial investigation (one location at a time) and the risk of afterdischarges in localizing eloquent cortex. Electrocorticographic frequency alteration mapping (EFAM) allows the parallel investigation of many cortical sites in much less time and with no risk of afterdischarges because of its passive nature. We examined its use with ECS in the context of language mapping during an awake craniotomy for a tumor resection. CLINICAL PRESENTATION: The patient was a 61-year-old right-handed Caucasian male who presented with headache and mild aphasia. Imaging demonstrated a 3-cm cystic mass in the posterior temporal-parietal lobe. The patient underwent an awake craniotomy for the mapping of his speech cortex and resection of the mass. INTERVENTION: Using a 32-contact electrode array, electrocorticographic signals were recorded from the exposed cortex as the patient participated in a 3-min screening task involving active (patient naming visually presented words) and rest (patient silent) conditions. A spectral comparison of the 2 conditions revealed specific cortical locations associated with activation during speech. The patient was then widely mapped using ECS. Three of 4 sites identified by ECS were also identified passively and in parallel by EFAM, 2 with statistical significance and the third by qualitative inspection. CONCLUSION: EFAM was technically achieved in an awake craniotomy patient and had good concordance with ECS mapping. Because it poses no risk of afterdischarges and offers substantial time savings, EFAM holds promise for future development as an adjunct intraoperative mapping tool. Additionally, the cortical signals obtained by this modality can be utilized for localization in the presence of a tumor adjacent to the eloquent regions.

Two-dimensional movement control using electrocorticographic signals in humans.

We show here that a brain-computer interface (BCI) using electrocorticographic activity (ECoG) and imagined or overt motor tasks enables humans to control a computer cursor in two dimensions. Over a brief training period of 12-36 min, each of five human subjects acquired substantial control of particular ECoG features recorded from several locations over the same hemisphere, and achieved average success rates of 53-73% in a two-dimensional four-target center-out task in which chance accuracy was 25%. Our results support the expectation that ECoG-based BCIs can combine high performance with technical and clinical practicality, and also indicate promising directions for further research.

Decoding two-dimensional movement trajectories using electrocorticographic signals in humans.

Signals from the brain could provide a non-muscular communication and control system, a brain-computer interface (BCI), for people who are severely paralyzed. A common BCI research strategy begins by decoding kinematic parameters from brain signals recorded during actual arm movement. It has been assumed that these parameters can be derived accurately only from signals recorded by intracortical microelectrodes, but the long-term stability of such electrodes is uncertain. The present study disproves this widespread assumption by showing in humans that kinematic parameters can also be decoded from signals recorded by subdural electrodes on the cortical surface (ECoG) with an accuracy comparable to that achieved in monkey studies using intracortical microelectrodes. A new ECoG feature labeled the local motor potential (LMP) provided the most information about movement. Furthermore, features displayed cosine tuning that has previously been described only for signals recorded within the brain. These results suggest that ECoG could be a more stable and less invasive alternative to intracortical electrodes for BCI systems, and could also prove useful in studies of motor function.

Pseudo-pseudohypercalcaemia, apparent primary hyperparathyroidism and Waldenström's macroglobulinaemia.

An apparent primary hyperparathyroidism was reported due to pseudo-pseudohypercalcaemia in a 74-year-old man with Waldenström's macroglobulinaemia. It is important to recognise artificially elevated serum calcium levels so as to avoid erroneous diagnosis, unnecessary investigations and potentially inappropriate treatment.

Plasma nitrotyrosine in reversible myocardial ischaemia.

BACKGROUND: Nitric oxide (NO) plays a vital role in vascular homeostasis and in the pathophysiology of coronary heart disease. Its metabolites, nitrite and nitrate, have vasculoprotective properties, whereas peroxynitrite, an oxidant metabolite of NO, is cytotoxic and can aggravate myocardial damage during ischaemic reperfusion injury. Peroxynitrite nitrates free and protein bound tyrosine residues to produce nitrotyrosine. The measurement of nitrotyrosine provides an indirect estimation of plasma peroxynitrite concentrations. AIMS: To measure plasma nitrotyrosine concentrations to see whether peroxynitrite could contribute to myocardial dysfunction during myocardial ischaemia induced by an exercise tolerance test (ETT). MATERIALS/METHODS: Plasma free nitrotyrosine concentrations were compared before and after exercise in 29 subjects with a positive ETT and 34 subjects with a negative ETT. RESULTS: Plasma nitrotyrosine concentrations were similar in patients with exercise induced myocardial ischaemia and controls. CONCLUSION: Peroxynitrite does not contribute to the myocardial dysfunction in reversible myocardial ischaemia.

Serum prolactin in human immunodeficiency virus infection.

Patients infected with human immunodeficiency virus (HIV) have higher serum prolactin compared to healthy controls but this is controversial. As part of a laboratory audit investigating the interference of macroprolactin in our prolactin assay, we investigated whether low biological activity macroprolactin could account for the increased serum prolactin concentrations observed in HIV infection. We, therefore, compared serum total prolactin and free prolactin in 32 subjects infected with HIV (HIV+ve) with 52 subjects not infected with HIV (HIV-ve). Serum total prolactin concentrations were similar in HIV+ve and HIV-ve patients [median (95% confidence limits); 167.0 (122.4 - 313.8) vs 206.5 (187.8 - 248.4) mU/L respectively]. Serum free prolactin concentrations were lower (p <0.005) in HIV+ve subjects than in HIV-ve subjects [112.0 (91.1-141.8) vs 171.0 (154.5 - 200.9) mU/L respectively; p<0.0005]. These results are consistent with the notion that low biological activity macroprolactin contributes to circulating prolactin concentrations in HIV+ve subjects.

Raised serum prolactin in rheumatoid arthritis: genuine or laboratory artefact?

OBJECTIVES: Serum prolactin concentrations have been reported as higher, similar or lower in patients with rheumatoid arthritis (RA) compared with control subjects. We investigated whether low biological activity macroprolactin (a prolactin antibody complex), which is detected variably in different prolactin immunoassays, could account for the discrepant total prolactin results reported in RA. METHODS: We compared serum total prolactin and free prolactin in 60 women with RA and 31 female controls. RESULTS: No subject had hyperprolactinaemia or macroprolactinaemia. Serum concentrations of total and free (monomeric) prolactin were higher (P<0.05) in women with RA [mean (s.d.), 225.6 (104.6) and 201.6 (95.4) mU/l respectively] compared with controls [175.0 (68.5) and 154.0 (60.9) mU/l respectively]. CONCLUSIONS: We report higher serum free prolactin concentrations in women with RA compared with control subjects. This result indicates that the higher serum total prolactin levels in patients with RA are the consequence of increased free prolactin concentrations and are not due to macroprolactin.

Lipaemia: an overrated interference?

Reagent method sheets for analysis of common serum analytes often highlight the possibility of interference from lipaemia but the information given is often brief and may not be instrument-specific. Thus study assesses the degree of interference from lipaemia in a range of common serum analytes on the Bayer Opera (with a serum blank) using a commercial polymer, LipoClear, as a lipid-clearing agent. Serum samples (mean serum triglyceride 6.89 [range 0.58-28.4] mmol/L) are analysed for 14 common chemistry analytes and the results compared before and after treatment with LipoClear. Results showed no significant critical differences in analyte values before and after treatment, except for an expected fall in total protein, phosphate, cholesterol and triglyceride concentrations. Most of the common analytes in use on the Bayer Opera are not subject to interference from lipaemia; however, we recommend that where method sheets indicate interference from lipaemia then this should be quantified for the analyte in question.

Effect of a protease inhibitor on in vitro stability of intact parathyroid hormone.

BACKGROUND: We investigated whether increased protease activity explains the increased in vitro degradation of intact parathyroid hormone (iPTH) observed in serum when compared to EDTA plasma. METHODS: Pre-dialysis blood samples for iPTH were taken from 11 patients with chronic renal failure and collected into plain glass tubes, tubes containing 200 KIU/mL aprotinin (a protease inhibitor) and EDTA tubes. All sample aliquots were separated at 20 min, 1 h, 2 h, 4 h, 8 h and 24 h post collection. RESULTS: Over 24 h, iPTH concentrations remained unchanged in EDTA tubes. iPTH concentrations were significantly lower in both plain tubes (P < 0.01) and aprotinin tubes (P < 0.001) at 24 h when compared to the baseline sample (20 min). At 24 h, iPTH concentrations in EDTA tubes were higher than in plain tubes (P < 0.001) and aprotinin tubes (P < 0.01). The addition of aprotinin to plain tubes significantly reduced the degradation of iPTH (P < 0.05) at 24 h. CONCLUSION: Aprotinin significantly reduces the in vitro degradation of iPTH in plain tubes at 24 h from 24.7% to 9.6%. We suggest that increased protease activity contributes to the decline in serum iPTH over time. As this is observed in serum and not plasma it suggests that the increased protease activity may be due to the clotting process.

Ethnic variation in C-reactive protein: UK resident Indo-Asians compared with Caucasians.

BACKGROUND: The increased prevalence of coronary heart disease (CHD) in UK resident Indo-Asians is unexplained by the traditional cardiovascular risk factors of dyslipidaemia, hypertension, smoking and diabetes mellitus. C-reactive protein (CRP) has been implicated in the pathogenesis of CHD but the data on ethnic variation in CRP is conflicting. We therefore investigated whether CRP could help explain the increased prevalence of CHD in Indo-Asians. DESIGN AND METHODS: We measured CRP, using a highly sensitive assay, in 102 men (63 Caucasians and 39 Indo-Asians) and 89 women (58 Caucasians and 31 Indo-Asians). All subjects, aged between 40 and 70 years, were nondiabetic and nonsmokers. RESULTS: Serum CRP correlated (P < 0.05) positively with coronary risk. Serum HDL cholesterol concentrations were lower (P<0.05) in Indo-Asian women when compared with Caucasian women, but otherwise the ethnic groups were matched for calculated coronary risk and cardiovascular risk factors. Serum CRP concentrations were similar in Indo-Asians (women 2.29 (1.52) mg/l [mean (SD)]; men 1.77 (1.46) mg/l) and Caucasians (women 2.23 (1.54) mg/l; men 1.94 (1.45) mg/l). CONCLUSIONS: Altered CRP concentrations does not appear to be implicated in the increased prevalence of CHD in UK resident Indo-Asians.

Comparative evaluation of the new Sheffield table and the modified joint British societies coronary risk prediction chart against a laboratory based risk score calculation.

BACKGROUND: Management of borderline hypertension and hypercholesterolaemia is based on an individual's coronary heart disease (CHD) risk rather than arbitrary values for blood pressure or serum cholesterol. Prediction of CHD risk involves using tables, charts, or computer programs based on the Framingham equations. The new Sheffield table and modified joint British societies coronary risk prediction (JBS) chart are widely used. The JBS chart approximates age and systolic blood pressure, and the new Sheffield table dichotomises blood pressure, and these simplifications may lead to diagnostic inaccuracy. METHODS: The diagnostic performance of the charts against an individualised laboratory based CHD risk calculation in 1102 subjects in primary care were evaluated and compared. RESULTS: The new Sheffield table and modified JBS chart performed equally well with a respective diagnostic sensitivity and specificity of 91.6% (95% confidence interval 86.7% to 95.1%) and 93.8% (91.1% to 97.9%), and 93.6% (90.4% to 96.0%) and 94.7% (92.6% to 96.1%) at 10 year CHD risk of 15%; and of 95.2% (82.8% to 99.4%) and 97.9% (96.8% to 98.7%), and 90.5% (75.6% to 97.4%) and 100% (99.7% to 100%) at 10 year CHD risk of 30%. The modified JBS chart graphic display provides graded risk, which may be an advantage over the new Sheffield table, which identifies thresholds of risk. The new Sheffield table, unlike any other method, can be used as screening tool for cholesterol measurement. CONCLUSIONS: The new Sheffield table and modified JBS chart are valid for use in primary care since their diagnostic accuracy is unaffected by approximations in age and blood pressure. It is suggested that practitioners should choose whichever risk assessment tool they are comfortable with and use it.