Hyperthermia increases the metastatic potential of murine melanoma

Hyperthermia, either alone or combined with radio-, immuno- or chemotherapy, can control tumor growth, but its effect on metastasis is still controversial. In the present study, we investigated the influence of hyperthermia on the metastatic potential of B16-F10 murine melanoma cells. Incubation of melanoma cells at 43ºC for 30 min led to a significant decrease in cell viability. About half of the cells survived the acute exposure to heat. These thermoresistant cells displayed a longer lag phase as compared to control unheated B16-F10 melanoma cells. Other parameters of cell growth such as doubling time and saturation density were equivalent in both control and thermoresistant cells. Both control and treated cells were adherent, but thermoresistant cells failed to spread during the first 48 h after heat exposure. B16-F10 cells colonize the lungs of C57BL/6J mice when injected intravenously; the number of lung colonies is a measure of the metastatic potential of injected cells. Median values of 22, 10.5 and 31 colonies per injected mouse were observed for control cells, cells heated to 43ºC for 30 min and thermoresistant cells, respectively, with statistically significant differences between groups (Mann-Whitney test, P<0.02). Thus, despite its cytotoxic action, heat exposure induced the acquisition of a more metastatic phenotype in a subpopulation of B16-F10 cells

Blockade of the action of nitric oxide in human septic shock increases systemic vascular resistance and has detrimental effects on pulmonary function after a short infusion of methylene blue

To investigate the role of nitric oxide in human sepsis, ten patients with severe septic shock requiring vasoactive drug therapy and mechanical ventilation were enrolled in a prospective, open, non-randomized clinical trial to study the acute effects of methylene blue, an inhibitor of guanylate cyclase. Hemodynamic and metabolic variables were measured before and 20, 40, 60, and 120 min after the start of a 1-h intravenous infusion of 4 mg/kg of methylene blue. Methylene blue administration caused a progressive increase in mean arterial pressure (60 [55-70] to 70 [65-100] mmHg, median [25-75th percentiles]; P<0.05), systemic vascular resistance index (649 [479-1084] to 1066 [585-1356] dyne s-1 cm-5 m-2; P<0.05) and the left ventricular stroke work index (35 [27-47] to 38 [32-56] g m-1 m-2; P<0.05) from baseline to 60 min. The pulmonary vascular resistance index increased from 150 [83-207] to 186 [121-367] dyne s-1 cm-5 m-2 after 20 min (P<0.05). Mixed venous saturation decreased from 65 [56-76] to 63 [55-69]% (P<0.05) after 60 min. The PaO2/FiO2 ratio decreased from 168 [131-215] to 132 [109-156] mmHg (P<0.05) after 40 min. Arterial lactate concentration decreased from 5.1 ± 2.9 to 4.5 ± 2.1 mmol/l, mean ± SD (P<0.05) after 60 min. Heart rate, cardiac filling pressures, cardiac output, oxygen delivery and consumption did not change. Methylene blue administration was safe and no adverse effect was observed. In severe human septic shock, a short infusion of methylene blue increases systemic vascular resistance and may improve myocardial function. Although there was a reduction in blood lactate concentration, this was not explained by an improvement in tissue oxygenation, since overall oxygen availability did not change. However, there was a significant increase in pulmonary vascular tone and a deterioration in gas exchange. Further studies are needed to demonstrate if nitric oxide blockade with methylene blue can be safe for patients with septic shock and, particularly, if it has an effect on pulmonary function.

The effects of 2,3-diphosphoglycerate, adenosine triphosphate, and glycosylated hemoglobin on the hemoglobin-oxygen affinity of diabetic patients

The position of the oxygen dissociation curve (ODC) is modulated by 2,3-diphosphoglycerate (2,3-DPG). Decreases in 2,3-DPG concentration within the red cell shift the curve to the left, whereas increases in concentration cause a shift to the right of the ODC. Some earlier studies on diabetic patients have reported that insulin treatment may reduce the red cell concentrations of 2,3-DPG, causing a shift of the ODC to the left, but the reports are contradictory. Three groups were compared in the present study: 1) nondiabetic control individuals (N = 19); 2) insulin-dependent diabetes mellitus (IDDM) patients (on insulin treatment) (N = 19); 3) non-insulin-dependent diabetes mellitus (NIDDM) patients using oral hypoglycemic agents and no insulin treatment (N = 22). The overall position of the ODC was the same for the three groups despite an increase of the glycosylated hemoglobin fraction that was expected to shift the ODC to the left in both groups of diabetic patients (HbA1c: control, 4.6%; IDDM, 10.5%; NIDDM, 9.0%). In IDDM patients, the effect of the glycosylated hemoglobin fraction on the position of the ODC appeared to be counterbalanced by small though statistically significant increases in 2,3-DPG concentration from 2.05 (control) to 2.45 µmol/ml blood (IDDM). Though not statistically significant, an increase of 2,3-DPG also occurred in NIDDM patients, while red cell ATP levels were the same for all groups. The positions of the ODC were the same for control subjects, IDDM and NIDDM patients. Thus, the PO2 at 50% hemoglobin-oxygen saturation was 26.8, 28.2 and 28.5 mmHg for control, IDDM and NIDDM, respectively. In conclusion, our data question the idea of adverse side effects of insulin treatment on oxygen transport. In other words, the shift to the left reported by others to be caused by insulin treatment was not detected.

Lack of evidence for the pathogenic role of iron and HFE gene mutations in Brazilian patients with nonalcoholic steatohepatitis

The hypothesis of the role of iron overload associated with HFE gene mutations in the pathogenesis of nonalcoholic steatohepatitis (NASH) has been raised in recent years. In the present study, biochemical and histopathological evidence of iron overload and HFE mutations was investigated in NASH patients. Thirty-two NASH patients, 19 females (59%), average 49.2 years, 72% Caucasians, 12% Mulattoes and 12% Asians, were submitted to serum aminotransferase and iron profile determinations. Liver biopsies were analyzed for necroinflammatory activity, architectural damage and iron deposition. In 31 of the patients, C282Y and H63D mutations were tested by PCR-RFLP. Alanine aminotransferase levels were increased in 30 patients, 2.42 ± 1.12 times the upper normal limit on average. Serum iron concentration, transferrin saturation and ferritin averages were 99.4 ± 31.3 g/dl, 33.1 ± 12.7% and 219.8 ± 163.8 µg/dl, respectively, corresponding to normal values in 93.5, 68.7 and 78.1% of the patients. Hepatic siderosis was observed in three patients and was not associated with architectural damage (P = 0.53) or with necroinflammatory activity (P = 0.27). The allelic frequencies (N = 31) found were 1.6 and 14.1% for C282Y and H63D, respectively, which were compatible with those described for the local population. In conclusion, no evidence of an association of hepatic iron overload and HFE mutations with NASH was found. Brazilian NASH patients comprise a heterogeneous group with many associated conditions such as hyperinsulinism, environmental hepatotoxin exposure and drugs, but not hepatic iron overload, and their disease susceptibility could be related to genetic and environmental features other than HFE mutations.

Hemochromatosis (HFE) gene mutations in Brazilian chronic hemodialysis patients

Patients with chronic renal insufficiency (CRI) have reduced hemoglobin levels, mostly as a result of decreased kidney production of erythropoietin, but the relation between renal insufficiency and the magnitude of hemoglobin reduction has not been well defined. Hereditary hemochromatosis is an inherited disorder of iron metabolism. The importance of the association of hemochromatosis with treatment for anemia among patients with CRI has not been well described. We analyzed the frequency of the C282Y and H63D mutations in the HFE gene in 201 Brazilian individuals with CRI undergoing hemodialysis. The analysis of the effects of HFE mutations on iron metabolism and anemia with biochemical parameters was possible in 118 patients of this study (hemoglobin, hematocrit, ferritin levels, transferrin saturation, and serum iron). A C282Y heterozygous mutation was found in 7/201 (3.4%) and H63D homozygous and heterozygous mutation were found in 2/201 (1.0%) and 46/201 (22.9%), respectively. The allelic frequencies of the HFE mutations (0.017 for C282Y mutation and 0.124 for H63D mutation) did not differ between patients with CRI and healthy controls. Regarding the biochemical parameters, no differences were observed between HFE heterozygous and mutation-negative patients, although ferritin levels were not higher among patients with the H63D mutation (P = 0.08). From what we observed in our study, C282Y/H63D HFE gene mutations are not related to degrees of anemia or iron stores in CRI patients receiving intravenous iron supplementation (P > 0.10). Nevertheless, the present data suggest that the H63D mutation may have an important function as a modulating factor of iron overload in these patients.

Direct-Driven Interior Magnet Permanent Magnet Synchronous Motors for a Full Electric Sports Car

The design process of direct-driven permanent magnet synchronous machines (PMSMs) for a full electric 4 ´ 4 sports car is presented. The rotor structure of the machine consists of two permanent magnet layers embedded inside the rotor laminations thus resulting in some inverse saliency, where the q-axis inductance is larger than the d-axis one. An integer slot stator winding was selected to fully take advantage of the additional reluctance torque. The performance characteristics of the designed PMSMs were calculated by applying a twodimensional finite element method. Cross-saturation between the d- and q-axes was taken into account in the calculation of the synchronous inductances. The calculation results are validated by measurements.

L-carnitine as an ergogenic aid for patients with chronic obstructive pulmonary disease submitted to whole-body and respiratory muscle training programs

The effects of adding L-carnitine to a whole-body and respiratory training program were determined in moderate-to-severe chronic obstructive pulmonary disease (COPD) patients. Sixteen COPD patients (66 ± 7 years) were randomly assigned to L-carnitine (CG) or placebo group (PG) that received either L-carnitine or saline solution (2 g/day, orally) for 6 weeks (forced expiratory volume on first second was 38 ± 16 and 36 ± 12%, respectively). Both groups participated in three weekly 30-min treadmill and threshold inspiratory muscle training sessions, with 3 sets of 10 loaded inspirations (40%) at maximal inspiratory pressure. Nutritional status, exercise tolerance on a treadmill and six-minute walking test, blood lactate, heart rate, blood pressure, and respiratory muscle strength were determined as baseline and on day 42. Maximal capacity in the incremental exercise test was significantly improved in both groups (P < 0.05). Blood lactate, blood pressure, oxygen saturation, and heart rate at identical exercise levels were lower in CG after training (P < 0.05). Inspiratory muscle strength and walking test tolerance were significantly improved in both groups, but the gains of CG were significantly higher than those of PG (40 ± 14 vs 14 ± 5 cmH2O, and 87 ± 30 vs 34 ± 29 m, respectively; P < 0.05). Blood lactate concentration was significantly lower in CG than in PG (1.6 ± 0.7 vs 2.3 ± 0.7 mM, P < 0.05). The present data suggest that carnitine can improve exercise tolerance and inspiratory muscle strength in COPD patients, as well as reduce lactate production.

Obese obstructive sleep apnea patients with tonsil hypertrophy submitted to tonsillectomy

The physiopathology of obstructive sleep apnea-hypopnea syndrome (OSAHS) is multifactorial and obesity has been shown to be one of the main factors correlated with its occurrence. In obese patients with anatomical alterations of the upper airways it is often difficult to predict success for surgical correction since obesity is a limiting factor. Therefore, the aim of the present study was to evaluate the results of tonsillectomy in a specific group of patients, i.e., obese OSAHS patients with tonsil hypertrophy. Seven OSAHS patients with moderate obesity with obstructive palatine tonsil hypertrophy were submitted to tonsillectomy. All patients were submitted to pre- and postoperative appraisal of body mass index, otorhinolaryngology examination and polysomnography. Patients' average age was 36.4 ± 10.3 years and average preoperative body mass index was 36.6 ± 6.3 kg/m². Postoperative weight did not differ significantly from preoperative weight (P = 0.27). Average preoperative apnea and hypopnea index (AHI) was 81 ± 26/h and postoperative AHI was 23 ± 18/h (P = 0.0005). Average preoperative minimum oxyhemoglobin saturation (SaO2 min) was 69 ± 14% and the postoperative value was 83 ± 3% (P = 0.038). In relation to AHI, 6 (86%) of the 7 patients studied showed a reduction of 50% in relation to preoperative level and of these, 4 (57%) presented AHI of less than 20%. Only one patient presented a reduction of less than 50% in AHI, but even so showed improved SaO2 min. Tonsillectomy treatment for OSAHS in obese patients with obstructive palatine tonsil hypertrophy caused a significant reduction in AHI, with improvement in SaO2 min. This procedure could be eventually considered as an option of treatment for obese OSAHS patients with significant tonsil hypertrophy when continuous positive air pressure therapy is not possible as the first choice of treatment.

Magnetization studies of polystyrene/multiwall carbon nanotube composite films

Lappeenranta University of Technology School of Technology Technical Physics Evgenii Zhukov MAGNETIZATION STUDIES OF POLYSTYRENE/MULTIWALL CARBON NANOTUBE COMPOSITE FILMS Master’s thesis 2015 55 pages, 41 pictures, 9 Tables. Examiners: Professor Erkki Lähderanta D.Sc. Ivan Zakharchuk Keywords: polystyrene, multi-walled carbon nanotubes, MWCNT, composite, magnetization, SQUID. In this thesis magnetic properties of polystyrene/multiwall carbon nanotube (MWCNT) composites are investigated with Quantum Design SQUID magnetometer (MPMS XL). The surface of the composite films is studied via BRUKER Multimode 8 Atomic Force Microscope, as well. The polystyrene/MWCNT composites have been prepared by the group of professor Okotrub (Physics Chemistry of Nanomaterials laboratory, Nikolaev Institute of Inorganic Chemistry, Russia). The composite films have been prepared by solution processing and stretching method. The approximate length and inner diameter of the MWCNTs used in fabrication are 260 μm and 10 nm, respectively. The content of MWCNTs is 1 and 2.5 contents percent (wt%) for studied samples. The stretching of the samples is 30% for samples with 1 and 2.5 wt% content, and one sample with 1 wt% loading of MWCNTs is 100% stretched. MWCNTs aligned perpendicular to a silicon substrate are used as a reference sample. The magnetization field dependencies of the samples exhibit hysteresis behavior. The values of saturation magnetization of composite films are much less compared to that of the reference sample. The saturation magnetization coercitivity field value drops with decrease of MWCNT content. At high magnetic fields strong presence of diamagnetism is observed. Measurements in magnetic field parallel and perpendicular to the composite plate display anisotropy with respect to the direction of stretching. Temperature dependences of magnetization for all samples display difference between zero-field cooled and field-cooled curves of magnetization. This divergence confirms the presence of magnetic interactions in the material. The atomic force microscopy study of the composites’ surfaces revealed that they are relatively smooth and the nanotubes are aligned with the axis of stretching to some extent. 

Effects of sedation during upper gastrointestinal endoscopy on endocrine response and cardiorespiratory function

Upper gastrointestinal endoscopy is often accompanied by tachycardia which is known to be an important pathogenic factor in the development of myocardial ischemia. The pathogenesis of tachycardia is unknown but the condition is thought to be due to the endocrine response to endoscopy. The purpose of the present study was to investigate the effects of sedation on the endocrine response and cardiorespiratory function. Forty patients scheduled for diagnostic upper gastrointestinal endoscopy were randomized into 2 groups. While the patients in the first group did not receive sedation during upper gastrointestinal endoscopy, the patients in the second group were sedated with intravenous midazolam at the dose of 5 mg for those under 65 years or 2.5 mg for those aged 65 years or more. Midazolam was administered by slow infusion. In both groups, blood pressure, ECG tracing, heart rate, and peripheral oxygen saturation (SpO2) were monitored during endoscopy. In addition, blood samples for the determination of cortisol, glucose and C-reactive protein levels were obtained from patients in both groups prior to and following endoscopy. Heart rate and systolic arterial pressure changes were within normal limits in both groups. Comparison of the two groups regarding the values of these two parameters did not reveal a significant difference, while a statistically significant reduction in SpO2 was found in the sedation group. No significant differences in serum cortisol, glucose or C-reactive protein levels were observed between the sedated and non-sedated group. Sedation with midazolam did not reduce the endocrine response and the tachycardia developing during upper gastrointestinal endoscopy, but increased the reduction in SpO2.

Influence of Travelling Current Linkage Harmonics on Inductance Variation, Torque Ripple and Sensorless Capability of Tooth-Coil Permanent-Magnet Synchronous Machines

This paper introduces an important source of torque ripple in PMSMs with tooth-coil windings (TC-PMSMs). It is theoretically proven that saturation and cross-saturation phenomena caused by the non-synchronous harmonics of the stator current linkage cause a synchronous inductance variation with a particular periodicity. This, in turn, determines the magnitude of the torque ripple and can also deteriorate the performance of signal-injection-based rotor position estimation algorithms. An improved dq- inductance model is proposed. It can be used in torque ripple reduction control schemes and can enhance the self-sensing capabilities of TC-PMSMs

Is persistent hypotension after transient cardiogenic shock associated with an inflammatory response?

We evaluated the recovery of cardiovascular function after transient cardiogenic shock. Cardiac tamponade was performed for 1 h and post-shock data were collected in 5 domestic large white female pigs (43 ± 5 kg) for 6 h. The control group (N = 5) was observed for 6 h after 1 h of resting. During 1 h of cardiac tamponade, experimental animals evolved a low perfusion status with a higher lactate level (8.0 ± 2.2 vs 1.9 ± 0.9 mEq/L), lower standard base excess (-7.3 ± 3.3 vs 2.0 ± 0.9 mEq/L), lower urinary output (0.9 ± 0.9 vs 3.0 ± 1.4 mL·kg-1·h-1), lower mixed venous saturation, higher ileum partial pressure of CO2-end tidal CO2 (EtCO2) gap and a lower cardiac index than the control group. Throughout the 6-h recovery phase after cardiac tamponade, tamponade animals developed significant tachycardia with preserved cardiac index, resulting in a lower left ventricular stroke work, suggesting possible myocardial dysfunction. Vascular dysfunction was present with persistent systemic hypotension as well as persistent pulmonary hypertension. In contrast, oliguria, hyperlactatemia and metabolic acidosis were corrected by the 6th hour. The inflammatory characteristics were an elevated core temperature and increased plasma levels of interleukin-6 in the tamponade group compared to the control group. We conclude that cardiovascular recovery after a transient and severe low flow systemic state was incomplete. Vascular dysfunction persisted up to 6 h after release of tamponade. These inflammatory characteristics may also indicate that inflammatory activation is a possible pathway involved in the pathogenesis of cardiogenic shock.

Effect of smoking habits on sleep

To evaluate the effect of smoking habits on sleep, data from 1492 adults referred to the Sleep Institute were accessed and divided into 3 categories of smoking status: current, former and non-smokers. Categories of pack-years (<15 and ≥15) defined smoking severity. The association of smoking status and smoking severity with sleep was analyzed for sleep parameters, especially apnea and hypopnea index (AHI) ≥5, more than 5% of total sleep time (TST) spent with oxyhemoglobin saturation (SaO2) <90%, and arousal index. The arousal index was higher among current (21 ± 17) and former smokers (20 ± 17) than non-smokers (17 ± 15; P < 0.04). Former smokers had a higher percent of TST at SaO2 <90% than non-smokers (9 ± 18 vs 6 ± 13; P < 0.04). Former smokers with pack-years ≥15 compared to <15 exhibited higher AHI (22 ± 24 vs 16 ± 21; P < 0.05) and arousal index (22 ± 19 vs 18 ± 15; P < 0.05). Current smokers with pack-years ≥15 compared to <15 exhibited higher arousal index (23 ± 18 vs 18 ± 16; P < 0.05) and percent of TST at SaO2 <90% (11 ± 17 vs 6 ± 13; P < 0.05). Smoking status and pack-years were not associated with AHI ≥5 on logistic regression analysis, but current smokers with pack-years ≥15 were 1.9 times more likely to spend more than 5% of TST at SaO2 <90% than non-smokers (95%CI = 1.21-2.97; P = 0.005). The variability of arousal index was influenced by gender, AHI and current smokers with pack-years ≥15 (all P < 0.01). Smoking habits seem to be associated with arousal and oxyhemoglobin desaturation during sleep, but not with AHI. The effect was more pronounced in current than former smokers.

Relationship between disease severity and quality of life in patients with chronic obstructive pulmonary disease

Few studies have evaluated the relationship between Airways Questionnaire 20 (AQ20), a measure of the quality of life, scores and physiological outcomes or with systemic markers of disease in patients with chronic obstructive pulmonary disease (COPD). The aim of the present study was to investigate the relationship of forced expiratory volume in 1 s (FEV1), body mass index, fat-free mass index, 6-min walk test (6MWT) results, dyspnea sensation and peripheral oxygen saturation (SpO2) with the quality of life of COPD patients. Ninety-nine patients with COPD (mean age: 64.2 ± 9.2 years; mean FEV1: 60.4 ± 25.2% of predicted) were evaluated using spirometry, body composition measurement and the 6MWT. The baseline dyspnea index (BDI) and the Modified Medical Research Council (MMRC) scale were used to quantify dyspnea. Quality of life was assessed using the AQ20 and the St. George's Respiratory Questionnaire (SGRQ). The Charlson index was used to determine comorbidity. The body mass index/airflow obstruction/dyspnea/exercise capacity (BODE) index was also calculated. AQ20 and SGRQ scores correlated significantly with FEV1, SpO2, 6MWT, MMRC and BDI values as did with BODE index. In the multivariate analyses, MMRC or BDI were identified as predictors of AQ20 and SGRQ scores (P < 0.001 in all cases). Thus, the relationship between AQ20 and disease severity is similar to that described for SGRQ. Therefore, the AQ20, a simple and brief instrument, can be very useful to evaluate the general impact of disease when the time allotted for measurement of the quality of life is limited.

HFE gene mutations and iron status of Brazilian blood donors

Mutations of the HFE and TFR2 genes have been associated with iron overload. HFE and TFR2 mutations were assessed in blood donors, and the relationship with iron status was evaluated. Subjects (N = 542) were recruited at the Hemocentro da Santa Casa de São Paulo, São Paulo, Brazil. Iron status was not influenced by HFE mutations in women and was independent of blood donation frequency. In contrast, men carrying the HFE 282CY genotype had lower total iron-binding capacity (TIBC) than HFE 282CC genotype carriers. Men who donated blood for the first time and were carriers of the HFE 282CY genotype had higher transferrin saturation values and lower TIBC concentrations than those with the homozygous wild genotype for the HFE C282Y mutation. Moreover, in this group of blood donors, carriers of HFE 63DD plus 63HD genotypes had higher serum ferritin values than those with the homozygous wild genotype for HFE H63D mutation. Multiple linear regression analysis showed that HFE 282CY leads to a 17.21% increase (P = 0.018) and a 83.65% decrease (P = 0.007) in transferrin saturation and TIBC, respectively. In addition, serum ferritin is influenced by age (3.91%, P = 0.001) and the HFE 63HD plus DD genotype (55.84%, P = 0.021). In conclusion, the HFE 282Y and 65C alleles were rare, while the HFE 63D allele was frequent in Brazilian blood donors. The HFE C282Y and H63D mutations were associated with alterations in iron status in blood donors in a gender-dependent manner.