Feasibility to Measure Tissue Oxygen Saturation Using Textile-Integrated Polymer Optical Fibers.

Tissue oxygen saturation (StO2) is a crucial factor in the aetiology of pressure injury (PI), since hypoxia leads to necrotization. Pressure on the tissue occludes blood circulation and reduces the StO2, resulting in hypoxia. PI causes severe suffering, heals slowly and is expensive to treat. Hence it is important to prevent PI by detecting hypoxia, e.g., by near-infrared spectroscopy (NIRS) monitoring of StO2. For this, the NIRS device has to be wearable for a long time and it is crucial that it provokes no pressure itself. An integration of optical fibres into a textile achieves this. The aim was to investigate the feasibility of such a textile NIRS device.Knots and loops were tested as textile light emitters (LEs) or detectors (LDs) on a phantom. The light coupling efficiency of the LEs and LDs was investigated.Results show that knots perform similarly to loops. More loops per fibre increase efficiency both in LEs and in LDs. The best trade-off is at 3 loops. LEs are slightly more efficient than LDs, with an average attenuation from baseline of about -2 dB for loops of 0.5 mm diameter. Adding fibres multiplies the signal by the number of fibres. Inclusions mimicking hypoxia in phantoms were successfully identified. In-vivo arm occlusion tests showed the expected decrease in StO2. This shows feasibility of optical fibres in a textile to prevent PI.

Rupture and recoil of bent-core liquid crystal filaments.

The recoil process of free-standing liquid crystal filaments is investigated experimentally and theoretically. We focus on two aspects, the contraction speed of the filament and a spontaneously formed undulation instability. At the moment of rupture, the filaments buckle similarly to the classical Euler buckling of elastic rods. The tip velocity decays with decreasing filament length. The wavelength of buckling affinely decreases with the retracting filament tip. The energy gain related to the decrease of the total length and surface area of the filaments is mainly dissipated by layer rearrangements during thickening of the fibre. A flow back into the meniscus is relevant only in the final stage of the recoil process. We introduce a model for the quantitative description of the filament retraction speed. The dynamics of this recoil behaviour may find relevance as a model for biology-related filaments.

[Embolization of pulmonary arteriovenous malformations with electrolytically detachable coils in patients with hereditary hemorrhagic telangiectasia]. / Embolisation pulmonaler arteriovenöser Malformationen bei hereditärer hämorrhagischer Teleangiektasie mittels elektrolytisch ablösbarer Spiralen.

BACKGROUND: Pulmonary arteriovenous malformations (PAVM) can be found in approximately 20 % to 35 % of patients with hereditary hemorrhagic telangiectasia (HHT). PAVM should be treated since they are a source of paradoxical embolization, potentially resulting in severe neurologic complications. The treatment of choice is the endovascular embolization with coils. PATIENTS AND METHODS: Seven patients with HHT underwent superselective embolization of PAVM detected during screening for PAVM. Four patients had a single PAVM and one patient 3, 4 and 5 PAVMs, respectively. Electrolytically detachable coils were used for embolization. In addition, coils with synthetic fibers were used during 6 embolizations for completion of embolization. RESULTS: Embolization was technically successful in all patients. Complete primary occlusion was achieved in all PAVM. No coil migration or occlusion of unaffected pulmonary arteries was observed. After embolization, one patient developed a small pleural effusion, which was treated symptomatically. CONCLUSION: As a minimally invasive procedure, superselective embolization is the treatment of choice in treating PAVM in patients with HHT. With the use of electrolytically detachable coils, the ideal coil size can be chosen and exact placement achieved without the risk of coil migration or occlusion of unaffected pulmonary arteries.

Octreotide in the prevention of pancreatic damage induced by endoscopic sphincterotomy.

Somatostatin and the long acting analogue octreotide have been proposed as a therapeutic agent in acute pancreatitis and for the prophylaxis of pancreatic damage by ERCP and EST for their ability to reduce exocrine pancreatic secretion. However, clinical trials could not show significant beneficial effects in acute pancreatitis and ERCP. In patients undergoing EST, data remained controversial, most authors describing positive effects of prophylaxis. In this study we investigated the use of octreotide prophylaxis to reduce EST-induced pancreatic damage in a randomised, double blind trial. 94 consecutive ERCP/EST-patients were randomised to receive either octreotide 200 microgram s.c. or placebo 3 times daily, starting the night before endoscopic procedures. In 59 patients EST was performed. Blood samples were collected before and 40 min, 2 hrs, 6 hrs, 24 hrs, 48 hrs and 72 hrs after the endoscopic procedures. Samples were analysed for pancreatic serum enzymes, acute phase proteins and blood counts. A clinical pain score was investigated. Post-EST-pancreatitis (amylase > 3x upper limit and persistent abdominal pain) was diagnosed in 3 patients in the treatment group, in 4 patients in the placebo group. There were no significant differences in the time-courses of serum enzymes or acute phase proteins in-between the groups, nor in the pain-score. According to these data, prophylactic octreotide application does not prevent acute pancreatic damage induced by endoscopic sphincterotomy.

Transarterial chemoembolization of advanced liver metastases of neuroendocrine tumors--a retrospective single-center analysis.

BACKGROUND: In neuroendocrine tumors, metastases are a negative prognostic factor for survival and quality of life. Transcatheter arterial chemoembolization (TACE) is thought to be an effective symptomatic and antiproliferative treatment in patients with otherwise progressive disease. METHODS: 62 chemoembolization procedures in 26 patients with progressive neuroendocrine tumors were reviewed. The underlying disease was carcinoid syndrome in 10, non-functional midgut tumor in 2, non-functional pancreatic tumor in 7, malignant insulinoma in 2 patients, non-functional tumor of the stomach in 1 and of unknown origin in 4 patients. Tumor burden of the liver was <25% in 3, 25-50% in 11, 50-75% in 6 and >75% in 6 patients. RESULTS: TACE was technically successful in 57 cases. Four patients developed minor and 5 major complications. The 30-day mortality rate was 7.7%. According to WHO criteria, 14 patients had no change in tumor burden, 2 had regression and 5 progress after chemoembolization. Patients with a tumor burden >75% of the liver did not benefit from TACE due to the development of major complications, whereas patients with low (<50%) tumor burden and high (>50%) lipiodol uptake showed a trend towards longer survival. Five-year survival time after diagnosis was 48%. Patients treated with octreotide and/or alpha-interferon had no benefit from chemoembolization with regard to their carcinoid syndrome. CONCLUSIONS: In this retrospective study, patients with low (<50%) tumor burden and high (>50%) lipiodol uptake responded better to TACE than end-stage patients.

[Uveitis associated with rifabutin treatment. Apropos of 3 patients]. / Uvéite associée un traitement de rifabutine. A propos de 3 patients.

Disseminated Mycobacterium-avium complex (MAC) infection develops in most patients with AIDS. We report three cases of anterior uveitis with vitritis in AIDS patients treated by the combination of rifabutin, clarithromycin and ethambutol for MAC bacteremia. Uveitis secondary to the introduction of rifabutin treatment is suggested.

Determination of elastase-1 serum levels in post ERCP/EST pancreatic damage.

Recently an ELISA using specific antibodies to detect elastase-1 in serum has become available. Earlier studies using a radioimmunoassay reported a prolonged elevation of serum elastase as compared to other pancreatic enzymes in acute pancreatitis. The aim of the present study was to compare the changes of serum levels of ELISA-elastase-1, lipase and amylase in acute pancreatic damage following ERCP. Blood samples were prospectively collected at five time points before and after the endoscopic procedures in 212 patients. Samples were analyzed for pancreatic serum enzymes, acute phase proteins and routine parameters. A pain score was used for clinical evaluation. Relevant post ERCP pancreatic damage was defined as CRP elevation from < 10 mg/l to > 10 mg/l in the presence of persistent abdominal pain without laboratory evidence of cholangitis and without clinical or laboratory signs of pancreatitis before the endoscopic procedures. Elastase-1 time course paralleled the courses of lipase and amylase peeking at six hrs. There was no prolonged elevation of elastase-1. Ten out of 204 patients (4.9%) were found to have relevant pancreatic damage. Depending on the cut off point used, sensitivity/specificity were as follows: lipase 80-100%/30.9-71.6%; amylase 70-90%/44.3-88.7%; elastase-1 60-90%/64.9-81.4%. In conclusion ELISA-elastase-1 is a marker of acute pancreatic damage similar to lipase and amylase. Although elastase-1 may show a better specificity than the other enzymes, this seems to be a matter of definition of the normal range. The determination of serum ELISA-elastase-1 does not provide additional information in acute pancreatic damage as compared to a combination of lipase and amylase.

Diagnostic relevance of interleukin pattern, acute-phase proteins, and procalcitonin in early phase of post-ERCP pancreatitis.

Post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis has been suggested as a model for acute pancreatitis (AP), which allows evaluation of early alterations in the time course of the disease. The influence of the clinical course on procalcitonin (PCT), serum amyloid A (SAA), and several proinflammatory and inhibitory cytokines was evaluated in patients with AP following ERCP. Blood samples were prospectively collected from patients undergoing ERCP. The incidence of ERCP-induced pancreatic damage, defined as abdominal complaints, a threefold increase of serum lipase, and elevation of CRP from <10 to >20 mg/liter was 12.8% (12/94). Only mild clinical courses of acute pancreatitis were observed. PCT significantly increased in subjects with post-ERCP pancreatitis after 24 hr. However, PCT levels did not exceed 0.5 ng/ml in any patient. Interleukin-1 receptor antagonist (IL-1RA) began to differ from baseline 2 hr after ERCP, followed by interleukin-6 (IL-6, 6 hr), solubilized tumor necrosis factor-alpha receptor II (sTNF-alphaRII, 24 hr) and SAA (24 hr). Interleukin 10 (IL-10) showed marked interindividual variations with no obvious peak. Among all parameters evaluated, only peak values of IL-6 and IL-10 showed significant correlations with the reported pain score (r2 = 0.62/0.78), degree of ampullar irritation (r2 = NS/0.87), and the duration of ERCP (r2 = 0.58/0.76). No correlation was found with the volume of the injected contrast agent. We conclude that IL-10 and IL-6 appear to be useful to monitor patients after ERCP. The absence of any PCT elevation in the present study is in accordance with the clinical course of the patients who suffered from mild pancreatic damage without systemic or infectious complications.