A THz transparent 3D printed microfluidic cell for small angle x-ray scattering.

Excitation frequencies in the terahertz (THz) range are expected to lead to functionally relevant domain movements within the biological macromolecules such as proteins. The possibility of examining such movements in an aqueous environment is particularly valuable since here proteins are not deprived of any motional degrees of freedom. Small angle x-ray scattering (SAXS) is a powerful method to study the structure and domain movements of proteins in solution. Here, we present a microfluidic cell for SAXS experiments, which is also transparent for THz radiation. Specifically, cell dimensions and material were optimized for both radiation sources. In addition, the polystyrene cell can be 3D printed and easily assembled. We demonstrate the practicality of our design for SAXS measurements on several proteins in solution.

Second Harmonic Generation of Nanoscale Phonon Wave Packets.

Phonons are often regarded as delocalized quasiparticles with certain energy and momentum. The anharmonic interaction of phonons determines macroscopic properties of the solid, such as thermal expansion or thermal conductivity, and a detailed understanding becomes increasingly important for functional nanostructures. Although phonon-phonon scattering processes depicted in simple wave-vector diagrams are the basis of theories describing these macroscopic phenomena, experiments directly accessing these coupling channels are scarce. We synthesize monochromatic acoustic phonon wave packets with only a few cycles to introduce nonlinear phononics as the acoustic counterpart to nonlinear optics. Control of the wave vector, bandwidth, and consequently spatial extent of the phonon wave packets allows us to observe nonlinear phonon interaction, in particular, second harmonic generation, in real time by wave-vector-sensitive Brillouin scattering with x-rays and optical photons.

High sex determining region Y-box 2 expression is a negative predictor of occult lymph node metastasis in early squamous cell carcinomas of the oral cavity.

BACKGROUND: The transcription factor sex determining region Y (SRY)-box 2 (SOX2) (3q26.3-q27) has been recently identified as a recurrently activated major oncogene in squamous cell carcinoma of various sites. Its prognostic value in head and neck squamous cell carcinoma (HNSCC) is currently unclear. AIM: To correlate SOX2 protein expression with the occurrence of occult lymph node metastasis and relapse free survival in early oral SCC. METHODS: SOX2 expression in 120 T1/T2 oral SCC patients was evaluated using a tissue microarray technique. Intensity of SOX2 expression was quantified by assessing the Intensity/Reactivity Scores (IRSs). These scores were correlated with the lymph node status of biopsied sentinel lymph nodes and recurrence. Log rank univariate and Cox regression multivariate analysis was used to determine statistical significance. RESULTS: Twenty-six of 120 primary tumours (21.7%) showed high SOX2 expression. High expression levels of SOX2 significantly correlated with negative lymph node status in univariate (p=0.001) and multivariate analysis (p=0.003). Sensitivity was found to be 95.6% with a negative predictive value of 92.3%. Specificity was 32% with a positive predictive value of 45.7%. CONCLUSION: SOX2 up-regulation is frequent in early SCC of the oral cavity and associated with decreased risk of lymphatic metastasis. SOX2 immunohistochemistry may be used as a predictor for lymph node metastasis in squamous cell carcinoma of the oral cavity.

Merkel cell carcinoma of the head and neck: a single institutional experience.

Merkel cell carcinoma (MCC) is a rare cutaneous malignancy occurring mostly in older immunocompromized Caucasian males. A growing incidence of MCC has been reported in epidemiological studies. Treatment of MCC usually consists of surgical excision, pathological lymph node evaluation, and adjuvant radiotherapy. This paper reports the experience of a single tertiary center institution with 17 head and neck Merkel cell carcinoma patients. Median followup for the cohort was 37.5 months. After five years, recurrence-free survival, disease specific survival, and overall survival were 85%, 90%, and 83%, respectively. Our limited data support the use of adjuvant radiotherapy. We also report two cases of MCC located at the vestibule of the nose and two cases of spontaneous regression after diagnostic biopsy. About 40% of our patients were referred to our center for surgical revision and pathological lymph node evaluation. Increased awareness of MCC and an interdisciplinary approach are essential in the management of MCC.

Phase diagrams of monoacylated amide-linked disaccharide glycolipids.

A series of monoacylated glycolipids with even-numbered acyl chain lengths ranging from saturated C11 to C15 and an unsaturated C17:1 fatty acid connected by an amide in linkage to the disaccharide head groups maltose, melibiose and lactose were synthesized. The structural polymorphism of the glycolipids was investigated using Fourier-transform infrared spectroscopy and differential scanning calorimetry for the detection of the gel to liquid-crystalline acyl chain melting behaviour and small-angle X-ray scattering for the elucidation of the physical structure of the lipid aggregates. Also, the phase morphology was studied by polarizing microscopy in contact preparations. The data clearly show the existence of uni- and multilamellar structures. Although only one acyl chain is present, there is no evidence for the existence of micelles - of spherical or of cylindrical (H(I)) type - or of interdigitated phases. The preference for lamellar phases seems to be correlated with the intrinsic high conformational order of the amide linkage of these compounds which inhibits the formation of highly curved structures.

Automated sample-changing robot for solution scattering experiments at the EMBL Hamburg SAXS station X33.

There is a rapidly increasing interest in the use of synchrotron small-angle X-ray scattering (SAXS) for large-scale studies of biological macromolecules in solution, and this requires an adequate means of automating the experiment. A prototype has been developed of an automated sample changer for solution SAXS, where the solutions are kept in thermostatically controlled well plates allowing for operation with up to 192 samples. The measuring protocol involves controlled loading of protein solutions and matching buffers, followed by cleaning and drying of the cell between measurements. The system was installed and tested at the X33 beamline of the EMBL, at the storage ring DORIS-III (DESY, Hamburg), where it was used by over 50 external groups during 2007. At X33, a throughput of approximately 12 samples per hour, with a failure rate of sample loading of less than 0.5%, was observed. The feedback from users indicates that the ease of use and reliability of the user operation at the beamline were greatly improved compared with the manual filling mode. The changer is controlled by a client-server-based network protocol, locally and remotely. During the testing phase, the changer was operated in an attended mode to assess its reliability and convenience. Full integration with the beamline control software, allowing for automated data collection of all samples loaded into the machine with remote control from the user, is presently being implemented. The approach reported is not limited to synchrotron-based SAXS but can also be used on laboratory and neutron sources.

Combining the hDAF transgene with the GP IIb/IIIa inhibitor tirofiban improves heart performance and reduces myocardial damage following hyperacute rejection in an ex vivo perfusion model.

Xenograft rejection is associated with vascular injury resulting at least in part from platelet activation, and rejected xenografts invariably demonstrate intravascular thrombosis. Assuming that complement activation is a major determinant of humoral immune reactions bringing about platelet-endothelial cell interactions, we tested the effects of the specific platelet glycoprotein IIb/IIIa inhibitor tirofiban in combination with the human decay accelerating factor (hDAF) transgene on hyperacute rejection of pig hearts. Four groups were studied in a working heart-perfusion model. Pig hearts transgenic for hDAF and nontransgenic pig hearts were perfused with human blood containing tirofiban or with unmodified human blood. Cardiac output, stroke work index, and creatine phosphokinases were measured for the evaluation of the extent of myocardial damage. Consumption of complement components was determined. Endothelial deposition of fibrin and intravascular thrombosis were evaluated. Tirofiban improved cardiac output and stroke work index of nontransgenic pig hearts and was able to further increase hemodynamic function of hDAF transgenic pig hearts. Low levels of creatine phosphokinases also revealed a cardioprotective effect of tirofiban. However, a further extension of the survival of hDAF transgenic pig hearts could not be achieved, although tirofiban prolonged beating time of nontransgenic pig hearts. Tirofiban was able to reduce the consumption of complement components independently of hDAF. Intravascular evidence of fibrin and thrombosis tended to be particularly reduced by the combination of tirofiban and hDAF. Thus, the application of tirofiban together with hDAF improves the performance of pig hearts by reducing myocardial damage and intravascular thrombosis.

Precipitation of overt encephalopathy in the portacaval shunted rat: towards the development of an adequate model of chronic portal systemic encephalopathy.

OBJECTIVE: To assess the feasibility of developing a model of overt portal-systemic encephalopathy (PSE) in rats with a surgically constructed portacaval anastomosis (PCA). DESIGN: The ability of increasing the load of nitrogenous substances in the gastrointestinal tract and/or further decreasing hepatocellular function to induce overt encephalopathy in rats with a PCA was determined. METHODS: The load of nitrogenous substances in the gastrointestinal tract was increased by feeding a pure horse-meat diet or by gavaging with blood. Partial hepatectomy and the induction of cirrhosis were used to decrease hepatocellular function further. The severity of encephalopathy was assessed using a neurobehavioural scale. RESULTS: Overt encephalopathy was not induced in rats by a PCA alone, by a PCA plus a horse-meat diet, by a PCA plus induction of cirrhosis, or by a PCA plus a 50% hepatectomy. Predominantly mild, but overt, encephalopathy was induced in rats with a PCA alone by gavaging with blood and a higher incidence of more severe overt encephalopathy was induced in rats with a PCA combined with either cirrhosis or partial hepatectomy by gavaging with blood. Although these models of PSE were associated in some instances with plasma ammonia concentrations about 25 times higher than normal, no seizures were observed. CONCLUSION: A syndrome that resembles overt PSE in humans can be induced in the rat with a PCA by further reducing hepatocellular function and also gavaging with blood. Although the rat with a PCA has been. extensively used as a model in studies relating to the pathogenesis of PSE, a syndrome resembling overt PSE in humans cannot readily be induced in rats with a PCA.

The transjugular stent implantation for the treatment of malignant portal and hepatic vein obstruction in cancer patients.

BACKGROUND: The increase in portal vascular resistance is a significant complication of metastatic disease to the liver or locally advanced cancer, e.g., biliary cancer. PATIENTS AND METHODS: This paper describes the successful palliative treatment of two cancer patients with portal hypertension presenting with the symptoms of tense ascites, mesenteric congestion, and severe variceal bleeding. By creating a stenttract between a hepatic vein and a main branch of the portal vein and/or by placing an extendable stent into the portal vein, the transjugular intrahepatic portosystemic stent-shunt (TIPS) technique was used to decompress the portovascular system. RESULTS: The TIPS-technique offers a new, safe and effective palliation for malignant portal hypertension. In both patients, the symptoms of the portal hypertension disappeared after the procedure. This was accompanied by a significant improvement of the patients performance status allowing an early ambulation. CONCLUSION: Our findings demonstrate the feasibility and effectiveness of the TIPS procedure as a minimal invasive treatment for portal vein decompression in selected tumor patients.

Arterio-biliary fistula after transjugular intrahepatic portosystemic shunt: a life-threatening complication of the new technique for therapy of portal hypertension.

We report on a 70-year old woman with chronic active hepatitis and portal gastropathy who was treated with TIPS. On day 28 after TIPS implantation hemobilia occurred and radiological examination of the abdomen showed migration and kinking of the portal stent. During an emergency intervention the dislocated stent was splinted with a further stent. The suspected portobiliary fistula, however, could not be detected. The subsequent angiography of the hepatic artery showed an arteriobiliary fistula in the area of the dislocated stent. By means of microparticles and coils this fistula could be occluded angiographically; the bleeding stopped completely. Three days after the successful occlusion of the arterio-biliary fistula the patient died of disseminated intravascular coagulation. We therefore recommend in case of hemobilia after TIPS placement an immediate evaluation of the bleeding to exclude an arterio-biliary communication. In order to avoid stent dislocation it is advisable not to use combination of stents with a different design (e.g., Wall-stent and Palmaz-stent).

Morphologic and clinical results of the transjugular intrahepatic portosystemic stent-shunt (TIPSS).

The concept of transjugular intrahepatic portosystemic stent-assisted shunt (TIPSS) using the Palmaz iliac stent has been successfully accomplished in 18 of 24 patients representing a technical success rate of 75%. Fourteen were male, 4 female with a mean age of 60 years (range 34-84 years). According to classification of Child's and Turcotte, 6 were in stage A, 6 in stage B, and 6 in stage C. Five patients were treated on an emergency basis because of massive active bleeding. In 10 patients the portosystemic tract was created between the middle hepatic vein and the right main stem of the portal vein in 8, and the left main stem in 2 patients. In 8 patients, the shunt was established between the right hepatic vein and the right main branch of the portal vein. The portosystemic gradient in 18 patients was 29.9 +/- 6 mm Hg and dropped to an average of 16.9 +/- 4 mm Hg after shunt establishment. Within the early postprocedural period of 30 days, 1 patient died of direct complications of the procedure. Because of catheter dislocation, embolization of the percutaneous transhepatic approach to the portal vein after successful shunt "creation" could not be done and was followed by intraabdominal exsanguination. One patient died of an ARDS after TIPSS. A third developed pulmonary infection. In 13 patients, because of hematomas at the puncture site of the transhepatic approach, only the transjugular approach was elected for establishing TIPSS.(ABSTRACT TRUNCATED AT 250 WORDS)

The transjugular intrahepatic portosystemic stent-shunt (TIPSS): results of a pilot study.

The new concept of TIPSS (Transjugular Intrahepatic Portosystemic Stent-Shunt) using the Palmaz iliac stent was successfully accomplished in 9 patients with severe portal hypertension (7 alcoholic, 2 postinfectious liver cirrhosis) and histories of multiple life-threatening upper GI bleeding. All patients were considered noncandidates for surgical portal decompression. An intrahepatic central connection was made transjugularly between the right hepatic vein and the right portal vein in 8 patients and the left portal vein in 1. The portosystemic gradient dropped from an average of 29 +/- 7.2 mmHg to 17.8 +/- 2.9 mmHg immediately after, and to 15.7 +/- 2.8 mmHg at the latest follow-up control after the procedure. Seven patients survived the procedure and progressed to Child's A stage during the observation period of 1-10 months (mean 5 months). One patient died as a direct complication from the procedure, and another patient 11 days after the procedure from a severe nosocomial infection. In none of the surviving patients has bleeding from varices recurred or encephalopathic coma developed. In one patient the shunt diameter was moderately increased by a routine PTA catheter to further decrease the portosystemic gradient (23 to 14 mmHg) 3 months after the primary procedure. Autopsy in the two patients who died demonstrated open stent-shunts with early neoendothelial incorporation.

Transjugular intrahepatic portacaval stent shunt: preliminary clinical results.

A percutaneous transjugular, intrahepatic portacaval shunt was created by means of a combined jugular and transhepatic approach. In the hepatic tissue track joining the portal and hepatic veins balloon-expandable stents were placed. Two of three patients with life-threatening variceal bleeding and Child C liver cirrhosis benefited from the procedure. One patient in severe hepatorenal failure prior to the procedure died 11 days after the shunt procedure of pulmonary complications. This procedure may be a promising alternative to current therapy in high-risk patients with esophageal bleeding.

Hepatic encephalopathy. Application of visual evoked responses to test hypotheses of its pathogenesis in rats.

A previous study of the patterns of visual evoked responses (VERs) in rats was interpreted as providing support for the synergistic neurotoxins hypothesis of the pathogenesis of hepatic encephalopathy (HE) due to fulminant hepatic failure (FHF). In contrast, other studies of the patterns of VERs in rabbits with different encephalopathies were interpreted as providing support for the concept that increased GABA-ergic tone may contribute to the neural inhibition of HE due to FHF. To attempt to resolve the discordant findings in these studies, additional studies of VERs have been undertaken in rats. To induce increased tissue levels of ammonia, mercaptans and fatty acids which are found in HE due to FHF, carefully predetermined doses of urease, dimethyldisulphide and octanoic acid were administered. The (pre-seizure) encephalopathy induced by these three agents was associated with abnormalities of the VER waveform that were fundamentally different from the abnormalities of the VER waveform associated with HE due to thioacetamide-induced FHF. However, the VER waveform in this model of HE due to FHF resembled closely that associated with pentobarbital-induced encephalopathy. These findings are in satisfactory agreement with those in the previous analogous studies in rabbits. They do not provide support for the synergistic neurotoxins hypothesis of the pathogenesis of HE, but are entirely consistent with increased GABA-ergic tone contributing to the neural inhibition of HE due to FHF.