A non-collinear autocorrelator for single-shot characterization of ultrabroadband terahertz pulses.

Conventional terahertz (THz) waveform or spectral diagnostics mainly employ the electro-optic-based techniques or the multi-shot Michelson interferometer. Simultaneously, single-shot, ultrabroadband THz spectral measurements remain challenging. In this paper, a novel probe-free scheme based on the non-collinear autocorrelation technique is proposed to characterize the ultrabroadband THz spectrum at a single-shot mode. The non-collinear autocorrelator is a modified beam-division interferometer, in which the two beams are recombined non-collinearly onto a camera. The temporal or spectral resolution and range depend on the noncollinear configuration and camera parameters. This simple approach has been applied experimentally to characterize the ultrashort THz pulse generated from ultraintense laser-solid interactions, demonstrating the capability of single-shot ultrabroadband measurements without an auxiliary ultrafast laser probe. The proposed non-collinear autocorrelator here would be much useful for characterization and applications of low-repetition-rate intense THz sources and could also be extended to other frequency bands.

Highly efficient generation of GV/m-level terahertz pulses from intense femtosecond laser-foil interactions.

The terahertz radiation from ultraintense laser-produced plasmas has aroused increasing attention recently as a promising approach toward strong terahertz sources. Here, we present the highly efficient production of millijoule-level terahertz pulses, from the rear side of a metal foil irradiated by a 10-TW femtosecond laser pulse. By characterizing the terahertz and electron emission in combination with particle-in-cell simulations, the physical reasons behind the efficient terahertz generation are discussed. The resulting focused terahertz electric field strength reaches over 2 GV/m, which is justified by experiments on terahertz strong-field-driven nonlinearity in semiconductors.

Essential role of mast cells in the visceral hyperalgesia induced by T. spiralis infection and stress in rats.

Mast cells (MCs) deficient rats (Ws/Ws) were used to investigate the roles of MCs in visceral hyperalgesia. Ws/Ws and wild control (+/+) rats were exposed to T. spiralis or submitted to acute cold restraint stress (ACRS). Levels of proteinase-activated receptor 2 (PAR2) and nerve growth factor (NGF) were determined by immunoblots and RT-PCR analysis, and the putative signal pathways including phosphorylated extracellular-regulated kinase (pERK1/2) and transient receptor potential vanilloid receptor 1 (TRPV1) were further identified. Visceral hyperalgesia triggered by ACRS was observed only in +/+ rats. The increased expression of PAR2 and NGF was observed only in +/+ rats induced by T. spiralis and ACRS. The activation of pERK1/2 induced by ACRS occurred only in +/+ rats. However, a significant increase of TRPV1 induced by T. spiralis and ACRS was observed only in +/+ rats. The activation of PAR2 and NGF via both TRPV1 and pERK1/2 signal pathway is dependent on MCs in ACRS-induced visceral hyperalgesia rats.

Vesicular glutamate transporter-3 contributes to visceral hyperalgesia induced by Trichinella spiralis infection in rats.

BACKGROUND: According to a recent study, vesicular glutamate transporter-3 (VGLUT3) contributes to injury-induced mechanical hyperalgesia in mice. AIMS: The aims of the study were to investigate whether VGLUT3 is involved in visceral pain, and whether transient intestinal infection or acute cold restraint stress (ACRS) affects VGLUT3 expression levels in rats. METHODS: Changes in VGLUT3 and c-Fos proteins were evaluated in rats which received noxious colorectal distension (CRD) stimulation. Transient intestinal infection was effected by oral administration of Trichinella spiralis (T. spiralis) larvae in Brown Norway rats. On the 100th day post-infection (PI), half of the PI-rats and non infected controls were subjected to an ACRS procedure. The visceromotor response to CRD was measured using the abdominal withdrawal reflex (AWR) score. Immunofluorescence and western blot analysis were used to estimate the expression of VGLUT3 in both peripheral and central neurons. RESULTS: Noxious stimulation induced a significant increase in the expression of VGLUT3 in the L6S1 spinal dorsal horn. Compared with the control group, the pain threshold was significantly decreased in the ACRS, PI, and PI + ACRS groups. VGLUT3 expression in the L6S1 dorsal root ganglion (DRG) and spinal neurons were significantly increased in PI and PI + ACRS groups as compared with the control group. CONCLUSIONS: VGLUT3 is involved in conduction of visceral pain sensation and in visceral hyperalgesia induced by Trichinella spiralis infection in rats.

[Effects of infection and stress on transient receptor potential vanilloid receptor 1 and extracellular-regulated kinase in spinal cord of mast cell deficient rats].

OBJECTIVE: To investigate the effects of mast cells (MCs) and the relationship between the signal pathway including transient receptor potential vanilloid receptor 1 (TRPV1) and extracellular-regulated kinase (ERK) and MCs in rat models of visceral hyperalgesia triggered by infection and stress. METHODS: MCs deficient rats (WsRC Ws/Ws, Ws/Ws) and control (WsRC+/+, +/+) rats were exposed to Trichinella spiralis (T.spiralis) post-infection (PI) or submitted to acute cold restraint stress (ACRS). Visceral sensitivity was measured using the abdominal withdrawal reflex (AWR) score. Levels of TRPV1 and phosphorylated ERK1/2 (pERK1/2) proteins in L6S1 spinal cord segments were determined by Western blotting. RESULTS: Compared with control group (3.7±0.09), visceral hyperalgesia was enhanced in PI (2.52±0.13), ACRS (2.28±0.17) and PI+ACRS (2.25±0.12) groups of +/+ rats, P< 0.05. In Ws/Ws rats, compared with control group (3.25±0.20), visceral hyperalgesia was enhanced in PI (2.87± 0.14) and PI+ACRS (2.50±0.27) groups, P< 0.05, but not in ACRS group (2.97±0.22). Compared with control group (0.090±0.009), a significant increase of TRPV1 was observed in PI (0.121±0.012), ACRS (0.122±0.008) and PI+ACRS (0.129±0.008) in spinal cord of +/+ rats, P< 0.05. However, compared with control group (0.106±0.012), a significant increase of TRPV1 was observed in PI (0.140±0.008, P< 0.05) and PI+ACRS (0.156±0.010, P< 0.01) groups but not in ACRS group(0.132±0.014)in spinal cord of Ws/Ws rats. Compared with control group (0.58± 0.03), a significant increase of pERK1/2 was observed in PI (0.72±0.04), ACRS (0.75±0.04) and PI+ACRS (0.78± 0.01) in spinal cord of +/+ rats, P< 0.01. However, compared with control group (0.59±0.04), a significant increase of pERK1/2 was observed in PI (0.72±0.04, P< 0.05) and PI+ACRS (0.74±0.04, P< 0.05) groups but not in ACRS group(0.132±0.014)in spinal cord of Ws/Ws rats. CONCLUSION: The visceral hyperalgesia was enhanced in rats induced by T.spiralis infection and ACRS, however, the increased visceral hyperalgesia in rats induced by ACRS was dependent on MCs. The signal pathway proteins including TRPV1 and pERK1/2 were increased in rats induced by T.spiralis infection and ACRS, but the sensitizing TRPV1 or mobilizing ERK1/2 phosphorylation via a MCs-dependent mechanism plays an important role in ACRS-induced visceral hyperalgesia rats.

[Insulin protects the loss of colonic interstitial cells of Cajal and acetylcholine in patients with type 2 diabetes mellitus].

OBJECTIVE: A deficiency of interstitial cells of Cajal (ICC) and neuronal nitric oxide synthase (nNOS) in the gastrointestinal muscle layer have been shown in both diabetic animal models and patients with diabetes mellitus (DM), but little is known about the alteration of colonic acetylcholine (Ach) expression in patients with DM, and it is remain unclear whether those changes are related to different treatments. This study examined whether the ICC density, or the expression of Ach containing nerves in the colon, was altered in patients with type 2 DM, and whether those changes were protected by insulin treatment. METHODS: Paraffin embedded colonic specimens that have been fixed in 10% formalin were collected from 81 patients with colon cancer who underwent colectomy (non-DM as controls, M/F = 17/12; DM with insulin treatment, M/F = 12/12; DM with oral medication treatment, M/F = 19/9). Serial sections were stained with antibodies to c-kit and Ach using immunohistochemical method.Meanwhile, mast cells were stained with toluidine blue. The ICC number was calculated by subtraction of the number of mast cells from the number of c-kit positive cells. The number of ICC and the expression of Ach were compared among the controls and DM patients with different treatment. RESULTS: C-kit positive cells, which located within the inner muscle layer and muscular plexus mainly, were expressed in control group and they were much more regular and less vacuolization than that of controls. The density of both intramuscular-ICC (ICC-IM) and myenteric ICC (ICC-MY) were much lower in patients with DM than that in the controls. Furthermore, ICC density in DM patients who underwent insulin treatment was higher than that in patients with oral medical therapy (control vs insulin vs oral medication group: ICC-MY, 60.12 vs 23.95 vs 16.49, P = 0.000; ICC-IM, 41.79 vs 33.18 vs 25.88, P = 0.000). In addition, the alteration of Ach expression in colonic enteric nerves was similar as the pattern of ICC (control vs insulin vs oral medication group: 147.50 vs 103.82 vs 86.38, P = 0.000). There was no influence of gender and age to the alteration of ICC and Ach. CONCLUSIONS: The colonic ICC and Ach in DM patients is irregular, and the distribution is loose, with lots of vacuolization. The density of clonic ICC-IM and ICC-MY were lower in DM patients than that in controls accompanied with downregulation of enteric nerves Ach expression. These alterations could be protected by insulin treatment.

Alteration of cholinergic and peptidergic neurotransmitters in rat ileum induced by acute stress following transient intestinal infection is mast cell dependent.

BACKGROUND: Mast cells are implicated in the development of irritable bowel syndrome (IBS), which is associated with the activation of the "neural-immune" system. The aim of this study was to investigate the role of mast cells in the remodeling of cholinergic and peptidergic neurotransmitters induced by acute cold restriction stress (ACRS) post infection (PI) using mast cell deficient rats (Ws/Ws) and their wild-type controls (+/+). METHODS: Transient intestinal infection was initiated by giving 1500 Trichinella spiralis (T.S.) larvae by gavage. ACRS was induced for 2 hours at day 100 PI. Samples of terminal ilea were prepared for H&E staining, mast cell counting and activation and assessment of IL-1beta and IL-10. RESULTS: When infected, both strains of rats experienced an acute infectious stage followed by a recovery. Histological scores were significantly higher in infected rats compared with those of the non-infected controls at day 10 PI (10 day-PI vs. control: +/+: 2.75+/-0.17 vs. 0.42+/-0.09; Ws/Ws: 2.67+/-0.67 vs. 0.50+/-0.34; P<0.01). In +/+ rats, post-infection ACRS induced the formation of low-grade inflammation, represented by the imbalance of IL-1beta and IL-10 (IL-1beta: PI+ACRS vs. control: (1812.24+/-561.61) vs. (1275.97+/-410.21) pg/g, P<0.05; IL-10: PI+ACRS vs. control: (251.9+/-39.8) vs. (255.3+/-24.7) pg/g, P>0.05), accompanied by hyperplasia and activation of mast cells (PI+ACRS vs. control: 58.8+/-19.2 vs. 28.0+/-7.6; P<0.01). The balance between acetylcholine (ACh) and substance P (SP) was also disturbed (ACh: PI+ACRS vs. control: (743.94+/-238.72) vs. (1065.68+/-256.46) pg/g, P<0.05; SP: PI+ACRS vs. control: (892.60+/-231.12) vs. (696.61+/-148.61) pg/g, P<0.05). Nevertheless, similar changes of IL-1beta/IL-10 and ACh/SP were not detected in Ws/Ws rats. CONCLUSION: The imbalance of ACh/SP, together with the activation of mucosal immunity induced by post-infection ACRS were lacking in mast cell deficient rats, which supports the premise that mast cells play an important role in cholinergic and peptidergic remodeling in the ileum of rats.

[Establishment of irritable bowel syndrome rat model by combination of intestinal infection with Trichinella spiralis and acute stress].

OBJECTIVE: To establish the irritable bowel syndrome (IBS) rat model by the combination of acute stress and transient intestinal infection with Trichinella spiralis (T.S.). METHODS: The rat model of acute cold restraint stress post-infection (PI + ACRS) was established as following: the intestinal infection with 1500 T.S. in 1 ml saline to adult male BN rats was performed at Day 0 by gastric lavage. Then a 2-hour stimulus of ACRS was administered at Day 100. Age matched transiently infected without stress rats (PI) and normal rats served as controls (CON) (n = 6, for each). After anesthesia, all the rats underwent colonic manometry in vivo at Day 100. The colonic pressures at 3 different states (baseline for 20 min; 1 ml balloon distension stimulation for 5 min and 2 ml balloon distension stimulation for 20 min) were traced with a 5-minute interval between each two. The following parameters were recorded: (1) Duration (Dur.): total time of contractions during each state. (2) Maximum (Max.): highest amplitude of constructional waves (mm Hg). (3) Area: area under contraction waves. (4) Number (Num.): frequencies of contraction wave during each state. The visceromoter response to colorectal distension (CRD) was analyzed at Day 100 post-infection. And the distension volume of AWR 3 was detected for 5 times with a 20-min interval in each rat. RESULTS: The histological damage of intestine induced by T.S. infection is transient. Although such acute infectious features as epithelial edema, hyperemia and marked eosinophil infiltration appeared at Day 10 PI, the histological changes almost recovered at Day 100 PI in both the PI group and the PI + ACRS group. Both the stimuli of transient infection and the ACRS post-infection induced intestinal dysmotility and visceral hypersensitivity. The ACRS post infection further worsened the transiently induced infection. The parameters of Num, Max and Area in the PI + ACRS group were all significantly higher than those of the PI group [Max: (41 +/- 17) mm Hg vs (22 +/- 6) mm Hg, P = 0.000; Area: (7693 +/- 2822) mm Hg.s vs (5092 +/- 1687) mm Hgxs, P = 0.000; Num: 9.5 +/- 2.6 vs 6.6 +/- 3.1, P = 0.000]; so was the distension volume of AWR3 [(2.25 +/- 0.29) ml vs (2.52 +/- 0.32) ml, P = 0.004]. As compared with the range of normal values from controls, the abnormality rates of motility parameters and visceral threshold in PI + ACRS group also had an larger increment than those of the PI group (PI + ACRS: 50.0% - 87.5% and 100% respectively, PI: 25.0% - 37.5% and 90.0% respectively). CONCLUSION: The pathophysiological changes in the PI + ACRS rats are consistent with those of IBS. Aggravated by psychological factors, these rats reproduce the symptoms of intestinal dysmotility and visceral hypersensitivity. A proper animal model has been established for the investigation of IBS.

[Application of fluorescence in-situ hybridization and reverse transcription-polymerase chain reaction in molecular diagnosis of Ewing's sarcoma and primitive neuroectodermal tumor].

OBJECTIVE: To detect tumor specific chromosome translocations and associated fusion transcripts in paraffin-embedded tissue by interphase fluorescence in-situ hybridization (FISH) and reverse transcription polymerase chain reaction (RT-PCR), respectively, and to evaluate their diagnostic values for Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET). METHODS: Nuclei of the tumor cells and total RNA were extracted from 10 cases of ES/PNET. Interphase FISH was utilized to analyze the EWS gene translocation with a dual color, break apart probe (Vysis company). RT-PCR was used to detect t (11; 22) (q24; q12) and t (21; 22) (q22; q12) fusion transcripts. RESULTS: Among 10 cases of ES/PNET, the EWS-FLI1 fusion transcript was detected in 8 by RT-PCR. EWS-ERG fusion transcript was not detected in any of the cases. EWS gene translocation was found in 9 of 10 cases by FISH. CONCLUSIONS: Interphase FISH and RT-PCR can be reliably applied to paraffin-embedded tissues for molecular diagnosis of ES/PNET. Between the two approaches, interphase FISH provides a more sensitive and stable result.

[Mixed epithelial and stromal tumor of kidney].

OBJECTIVE: To study the clinicopathological features and differential diagnoses of mixed epithelial and stromal tumor of the kidney. METHODS: Clinical and pathological characteristics of 4 cases of mixed epithelial and stromal tumor of the kidney were studied. RESULTS: Three patients were female and one was male. All patients presented with flank pain and hematuria. Radiologic studies revealed cystic and solid masses involving the kidney. Grossly the tumors had a solid and cyst appearance. Microscopically, the tumors were composed of a mixture of stromal and epithelial elements. The epithelial elements were variable in cell types including cuboidal, hobnail and columnar cells. One case showed Müllerian and intestinal epithelial differentiations. Stromal elements essentially consisted of spindle cells, with thick-walled blood vessels and bands of smooth muscle cells as distinctive features of the tumor. Immunohistochemical staining revealed that the epithelial components were positive for AE1/AE3, whereas the stromal components were positive for ER, PR, and SMA. All patients underwent nephrectomy and were well without evidence of recurrence. CONCLUSIONS: Mixed epithelial and stromal tumor of the kidney is a benign neoplasm with distinct histopathological features. It should be distinguished from many other renal neoplasms. Surgical intervention is a preferred therapy.