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Biomedical subjects

Andreas de Weerth

Publications and source records attributed to Andreas de Weerth.

8 recordsLinked to original sources
PubMed2006

Use of modified multiband ligator facilitates circumferential EMR in Barrett's esophagus (with video).

BACKGROUND: Various techniques are available for EMR in the upper- and lower-GI tract. For early cancers of the esophagus, the "suck and cut" technique, which uses a transparent cap or variceal band ligator, is the most commonly practiced method. To facilitate multiple or circumferential EMR, a modified multiband variceal ligator (MBL) is introduced, which allows sequential banding and snare resection without the need to withdraw the endoscope. OBJECTIVE: To study the feasibility of modified MBL device in facilitating circumferential EMR of Barrett's esophagus (BE) that contains high-grade intraepithelial neoplasia (HGIN) and/or intramucosal cancer (IMC). DESIGN: To enable band delivery with a snare inserted in the therapeutic endoscope, the threading channel of the cranking device is enlarged from 2 to 3.2 mm. The 6-shooter MBL was used. PATIENTS: Ten consecutive patients (all men; median age, 62 years; range 43-82 years) with BE were treated. IMC and HGIN were found in 8 and 2 patients, respectively. INTERVENTIONS: EMR was performed with pure coagulating current when using a 1.5 x 2.5-cm mini hexagonal polypectomy snare. No submucosal saline solution injection was performed before resection. RESULTS: In 5 of 10 patients with circumferential BE of 2 to 9 cm in length (median, 4 cm), complete circumferential EMR was performed in 1 session by using 3 to 18 bands (median, 6). Four patients with 3- to 10-cm (median, 4 cm) long segment BE required 2 to 5 sessions (median, 3) with a total of 5 to 42 bands (median, 12). Another patient with multifocal HGIN and/or IMC in 24 of a total of 49 specimens was finally recommended for surgery because of technical difficulties caused by mural thickening after 4 sessions. No serious procedure-related complications were observed, except for 2 minor bleedings, which were controlled endoscopically. Seven patients developed strictures after circumferential EMR. All patients except 1 were successfully managed by weekly bougienage after a median of 5 sessions (range 3-11). Deep-wall tears developed in 1 patient during the fourth bougienage session, for which limited distal esophageal resection was performed with an uneventful outcome. CONCLUSIONS: The novel technique of MBL-EMR described here facilitated and simplified circumferential removal of BE that contained HGIN and/or IMC. However, the method is associated with a very high stricture rate if circumferential EMR is performed in a single session. Complete removal of BE should be achieved by repeated partial EMR. Long-term follow-up is needed to observe for late recurrence and to determine the clinical impact of this method.

Adult↗
PubMed2005

Aggressive endoscopic therapy for pancreatic necrosis and pancreatic abscess: a new safe and effective treatment algorithm (videos).

BACKGROUND: Pancreatic necrosis and pancreatic abscess are severe complications of acute pancreatitis. Surgery is associated with significant morbidity and mortality in these critically ill patients. Endoscopic therapy has the potential to offer a safer and more effective alternative treatment modality. However, its role needs to be further investigated. METHODS: This is a retrospective study of the outcome of consecutive patients with pancreatic necrosis and pancreatic abscess, all unfit to undergo surgery, who underwent a new aggressive endoscopic approach. The treatment includes (1) synchronous EUS-guided multiple transmural and/or transpapillary drainage procedures followed by balloon dilation of the cystogastrostoma or cystoduodenostoma, (2) daily endoscopic necrosectomy and saline solution lavage, and (3) sealing of pancreatic fistula by N-butyl-2-cyanoacrylate. RESULTS: Pancreatic necrosis and pancreatic abscesses were successfully drained in 13 patients, thus avoiding emergency surgery as an initial treatment. Surgery was completely avoided in 9 patients over a median follow-up of 8.3 months (range 3-81 months). Surgery was combined with endoscopic therapy in one patient because of abscess extension into the right paracolic gutter, which was not manageable by endoscopic drainage. Because of the "disconnected-duct syndrome," two patients later developed recurrent pseudocysts and underwent elective surgery. Complications included minor bleeding after balloon dilation and necrosectomy in 4 cases, which were self limiting or controlled endoscopically. CONCLUSIONS: This aggressive endoscopic approach shows promising results. It expands the potential for endoscopic treatment in patients with pancreatic necrosis and/or pancreatic abscess.

Abscess↗
PubMed2005

Intravenous iron sucrose versus oral iron supplementation for the treatment of iron deficiency anemia in patients with inflammatory bowel disease--a randomized, controlled, open-label, multicenter study.

OBJECTIVES: Anemia is a frequent complication in patients with inflammatory bowel disease (IBD). The optimal route for iron supplementation to replenish iron stores has not been determined so far. We therefore evaluated the efficacy and safety of intravenous iron sucrose as compared with oral iron sulfate for the treatment of iron deficiency anemia (IDA) in patients with IBD. METHODS: A randomized, prospective, open-label, multicenter study was performed in 46 patients with anemia and transferrin saturation <or=20% and/or serum ferritin concentrations <or=20 microg/L. The intravenous group received a single dose of iron sucrose of 7 mg iron/kg body weight, followed by five 200 mg infusions for the following 5 wks. The oral group received iron sulfate 100-200 mg per day for 6 wks. RESULTS: While a comparable increase in hemoglobin was observed for both administration routes (median increase 0.25 g/L in the intravenous group vs 0.21 g/L in the oral group), only iron sucrose led to a rise in serum ferritin concentrations. Intractable gastrointestinal adverse events caused permanent study drug discontinuation in five patients (20.8%) receiving iron sulfate, whereas only one patient (4.5%) had to be withdrawn because of side effects due to iron sucrose. CONCLUSIONS: Although being equal in short-term efficacy and overall tolerability our results suggest a better gastrointestinal tolerability for iron sucrose. Larger trials are mandatory to prove a possible advantage of iron sucrose in short- and long-term efficacy as well as in tolerability over iron sulfate in the management of IDA in IBD.

Abdominal Pain↗
PubMed2004

The cholecystokinin2-receptor mediates calcitonin secretion, gene expression, and proliferation in the human medullary thyroid carcinoma cell line, TT.

Gastrin-induced release of calcitonin from medullary thyroid carcinomas (MTC) is based on the expression of the cholecystokinin(2)-receptor (CCK(2)R) in these tumors. Recently, we have shown that the CCK(2)R is expressed not only in MTC but also in C-cells within the normal thyroid gland. The functions of the CCK(2)R in MTC and C-cells are largely unknown. We therefore explored the effects of gastrin-induced CCK(2)R stimulation in the highly differentiated MTC cell line, TT. CCK(2)R expression in TT-cells is detectable by RT-PCR as well as immunocytochemistry. Stimulation of the CCK(2)R by gastrin induces immediate release of calcitonin from TT-cells. Moreover, quantitative (LightCycler) RT-PCR demonstrates that gastrin stimulates transcription of the calcitonin and chromogranin A genes in TT-cells. TT-cell proliferation, assessed by counting of viable cells and (3)H-thymidine uptake, is markedly increased by gastrin. This effect is inhibited by the CCK(2)R-specific antagonist L-365,260. Our findings suggest physiological functions for the CCK(2)R in calcitonin-secretion and gene expression as well as a pathophysiological role in MTC proliferation. CCK(2)R antagonists might have therapeutic potential in these tumors.

Calcitonin↗
PubMed2004

Characterization of effusion-infiltrating T cells: benign versus malignant effusions.

PURPOSE: While naïve T cells circulate between peripheral blood and lymph nodes, memory effector T cells acquire certain surface molecules that enable them to travel to peripheral tissues and exert their effector function. We analyzed whether deficient numbers of effector-type T cells within the malignant effusion might contribute to tumor escape from immunosurveillance. EXPERIMENTAL DESIGN: We analyzed the expression of a broad range of adhesion molecules and chemokine receptors (CD62L, CD56, CCR4, CCR5, CCR7, CXCR3, CLA, and integrin alpha 4 beta 7) on tumor-associated lymphocytes in effusions and peripheral blood lymphocytes of patients with malignant ascites (n = 11) or malignant pleural effusion (n = 16). A tumor-associated lymphocyte:peripheral blood lymphocyte ratio was calculated as an indicator for homing of lymphocytes into the effusions and was compared with patients with nonmalignant ascites (n = 17). RESULTS: Patients with malignancies show an increased enrichment of T cells expressing the phenotype of "naïve" (CD62L+ and CD45RA+CCR7+), "central memory" (CD45RA-CCR7+), and type 2-polarized (CCR4+) T cells within their effusions. In contrast, enrichment of "effector"-type (CD45RA-CCR7- or CD45RA+CCR7-) and presumably type 1-polarized T cells (CCR5+) at the tumor site is deficient. The same is true for natural killer cells and potentially cytotoxic CD56+ T cells. CONCLUSIONS: Here we show for the first time that patients with malignant effusions show a deficient enrichment of T cells expressing the phenotype of type-1-polarized effector T cells at the tumor site. This mechanism is likely to contribute to the escape of tumor cells from immunosurveillance.

CD4-Positive T-Lymphocytes↗
PubMed2002

Expression of the cholecystokinin 2-receptor in normal human thyroid gland and medullary thyroid carcinoma.

OBJECTIVE: The cholecystokinin(2)-receptor (CCK(2)R) promotes secretion and cell growth induced by its ligands cholecystokinin (CCK) and gastrin. The receptor has recently been shown to be expressed in human medullary thyroid carcinomas (MTCs). The objective of this study was to analyze CCK(2)R expression in MTC samples of different tumor stages as well as in non-malignant thyroid tissues. DESIGN AND METHODS: Using RT-PCR we investigated 19 MTC samples and TT-cells (a human MTC cell line), as well as samples of normal thyroid. In addition, we performed immunohistochemistry using calcitonin- and CCK(2)R-specific antibodies on MTCs and samples of C-cell hyperplasia. RESULTS: We demonstrate for the first time that CCK(2)R is expressed not only in MTCs but in all samples of normal thyroid tissue. Using immunohistochemistry the receptor could be localized on calcitonin-secreting C-cells. The highest incidence of CCK(2)R expression in MTCs was observed in early-tumor stages, whereas CCK(2)R could not be detected in advanced or metastasized tumors. CONCLUSIONS: The expression of CCK(2)R in C-cells suggests a physiological function for gastrin and/or CCK in the regulation of calcitonin release, presumably related to bone and calcium metabolism. Moreover, these ligands might act as growth factors in MTCs. Efforts in the development of CCK(2)R scintigraphy for the detection of MTC lesions might have to consider a lower incidence of the receptor in advanced tumor stages.

Adolescent↗