Highly efficient siRNA delivery system into human and murine cells using single-wall carbon nanotubes.

Development of RNA interference (RNAi) technology utilizing short interfering RNA sequences (siRNA) has focused on creating methods for delivering siRNAs to cells and for enhancing siRNA stability in vitro and in vivo. Here, we describe a novel approach for siRNA cellular delivery using siRNA coiling into carboxyl-functionalized single-wall carbon nanotubes (SWCNTs). The CNT-siRNA delivery system successfully demonstrates nonspecific toxicity and transfection efficiency greater than 95%. This approach offers the potential for siRNA delivery into different types of cells, including hard-to-transfect cells, such as neuronal cells and cardiomyocytes. We also tested the CNT-siRNA system in a non-metastatic human hepatocellular carcinoma cell line (SKHep1). In all types of cells used in this work the CNT-siRNA delivery system showed high efficiency and apparent no side effects for various in vitro applications.

Postprandial gastric antral contractions in patients with gastro-oesophageal reflux disease: a scintigraphic study.

Disturbed gastric contractility has been found in manometric studies in patients with gastro-oesophageal reflux disease (GORD), but the pathophysiological role of this abnormality is unclear. We aimed at assessing postprandial gastric antral contractions and its relationships with gastric emptying and gastro-oesophageal reflux in GORD patients. Fasted GORD patients (n = 13) and healthy volunteers (n = 13) ingested a liquid meal labelled with 72 MBq of 99mTechnetium-phytate. Gastric images were acquired every 10 min for 2 h, for measuring gastric emptying half time. Dynamic antral scintigraphy (one frame per second), performed for 4 min at 30-min intervals, allowed estimation of both mean dominant frequency and amplitude of antral contractions. In GORD patients (n = 10), acidic reflux episodes occurring 2 h after the ingestion of the same test meal were determined by ambulatory 24-h oesophageal pH monitoring. Gastric emptying was similar in GORD patients and controls (median; range: 82 min; 58-126 vs 80 min; 44-122 min; P = 0.38). Frequency of antral contractions was also similar in both groups (3.1 cpm; 2.8-3.6 vs 3.2 cpm; 2.4-3.8 cpm; P = 0.15). In GORD patients, amplitude of antral contractions was significantly higher than in controls (32.7%; 17-44%vs 23.3%; 16-43%; P = 0.01), and correlated positively with gastric emptying time (R(s) = 0.58; P = 0.03) and inversely with the number of reflux episodes (R(s) = -0.68; P = 0.02). Increased amplitude of postprandial gastric antral contractions in GORD may comprise a compensatory mechanism against delayed gastric emptying and a defensive factor against acidic gastro-oesophageal reflux.

Dependent component analysis for the magnetogastrographic detection of human electrical response activity.

The detection of the basic electric rhythm (BER), composed of a 3 cycles min(-1) oscillation, can be performed using SQUID magnetometers. However, the electric response activity (ERA), which is generated when the stomach is performing a mechanical activity, was detected mainly by invasive electrical measurements and only recently was one report published describing its detection by magnetic measurements. This study was performed with the aim of detecting the ERA noninvasively after a meal. MGG recordings were made with a 74-channel first-order gradiometer (Magnes II, biomagnetic technologies) housed in a shielded room. Seven nonsymptomatic volunteers were measured in the study. Initially a 10 min recording was performed with the subject in the fasted state. A 250 kcal meal was given to the subject without moving out of the magnetometers and two epochs of 10 min each were acquired. The signals were processed to remove cardiac interference by an algorithm based on a variation of independent component analysis (ICA), then autoregressive and wavelet analysis was performed. Preliminary results have shown that there is an increase in the signal power at higher frequencies around (0.6 Hz-1.3 Hz) usually associated with the basic electric rhythm. The center of the frequency band and its width varied from subject to subject, demonstrating the importance of pre-prandial acquisition as a control. Another interesting finding was an increase in power after about 5 min of meal ingestion. This period roughly agrees with the lag phase of gastric emptying, measured by scintigraphy and other techniques. We confirm that MGG can detect the electric response activity in normal volunteers. Further improvements in signal processing and standardization of signal acquisition are necessary to ascertain its possible use in clinical situations.

Postprandial symptoms in dysmotility-like functional dyspepsia are not related to disturbances of gastric myoelectrical activity

Gastric dysrhythmias, such as tachy- or bradygastria, have been reported in patients with functional dyspepsia (FD), but their role in symptom production is uncertain. It is also not known whether gastric dysrhythmias in these patients can be elicited by physiological gastric distension with a meal. We investigated the relationships between symptoms after ingestion of different volumes of water following a test meal and gastric dysrhythmias in FD patients. Fourteen patients with dysmotility-like FD and 13 healthy volunteers underwent paired electrogastrography (EGG) studies. Fasted subjects ingested 150 ml of yoghurt with either 150 ml (low volume) or 300 ml (high volume) water in random order. Fasting and fed EGGs with monitoring of symptoms were performed in both studies. Ten FD patients (71.4 percent) reported upper abdominal discomfort and bloating after the low volume meal, but only one (7.1 percent) presented an abnormal EGG (dominant frequency in the 2-4-cpm range: 58 percent). Following the high volume meal, 7 patients (50 percent) had symptoms, but none had EGG abnormalities. No significant differences were found between FD patients and controls for any of the EGG variables, in any test. In FD patients with postprandial symptoms, the percentage of the EGG dominant frequency in the normal range (median, 84.6 percent; range, 76.0-100.0 percent) was similar (P > 0.20) to that in those without symptoms (88.5 percent; 75.0-100.0 percent). We conclude that disturbances of gastric myoelectrical activity are unlikely to play a role in the origin of postprandial upper abdominal discomfort and bloating in dysmotility-like FD.

Postprandial symptoms in dysmotility-like functional dyspepsia are not related to disturbances of gastric myoelectrical activity.

Gastric dysrhythmias, such as tachy- or bradygastria, have been reported in patients with functional dyspepsia (FD), but their role in symptom production is uncertain. It is also not known whether gastric dysrhythmias in these patients can be elicited by physiological gastric distension with a meal. We investigated the relationships between symptoms after ingestion of different volumes of water following a test meal and gastric dysrhythmias in FD patients. Fourteen patients with dysmotility-like FD and 13 healthy volunteers underwent paired electrogastrography (EGG) studies. Fasted subjects ingested 150 ml of yoghurt with either 150 ml (low volume) or 300 ml (high volume) water in random order. Fasting and fed EGGs with monitoring of symptoms were performed in both studies. Ten FD patients (71.4%) reported upper abdominal discomfort and bloating after the low volume meal, but only one (7.1%) presented an abnormal EGG (dominant frequency in the 2-4-cpm range: 58%). Following the high volume meal, 7 patients (50%) had symptoms, but none had EGG abnormalities. No significant differences were found between FD patients and controls for any of the EGG variables, in any test. In FD patients with postprandial symptoms, the percentage of the EGG dominant frequency in the normal range (median, 84.6%; range, 76.0-100.0%) was similar (P>0.20) to that in those without symptoms (88.5%; 75.0-100.0%). We conclude that disturbances of gastric myoelectrical activity are unlikely to play a role in the origin of postprandial upper abdominal discomfort and bloating in dysmotility-like FD.