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Biomedical subjects

J M Müller

Publications and source records attributed to J M Müller.

At least 127 records · Page 7Linked to original sources
PubMed1998

A method for adjusting a malpositioned bifurcated aortic endograft.

PURPOSE: To report the successful application of a method to adjust a malpositioned bifurcated stent-graft after endovascular aortic aneurysm repair. METHOD AND RESULTS: A 62-year-old male patient underwent endovascular repair of a 5.1-cm abdominal aortic aneurysm (AAA) with a Vanguard bifurcated stent-graft. After complete deployment of the stent-graft, the intraoperative completion angiogram disclosed unexpected occlusion of the left renal artery. Intra-aortic adjustment of the bifurcated graft was possible with a crossover guidewire, which was pulled caudally. The method worked perfectly to restore blood flow to the left renal artery. The patient is well 16 months postoperatively without any evidence of endoleak or graft migration; the left renal artery remains open. CONCLUSIONS: A technique is demonstrated for intra-aortic repositioning of a bifurcated stentgraft to correct insufficient deployment. If required, this technique should be attempted before conversion to an open procedure.

Angiography, Digital Subtraction↗
PubMed1998

Combined surgical and endovascular removal of thrombus entirely occluding a bifurcated aortic stent-graft.

PURPOSE: To explore a method combining interventional, endovascular, and conventional surgical techniques for treating a completely occluded bifurcated stent-graft after endovascular aortic aneurysm repair. METHODS AND RESULTS: A 60-year-old patient underwent endovascular repair of an abdominal aortic aneurysm (AAA) with a Talent bifurcated stent-graft. Five months later, after chronic thrombotic occlusion of the right iliac limb, he presented with acute occlusion of the entire stent-graft. Local intra-arterial infiltration thrombolysis successfully reconstituted flow through the main aortic segment and left iliac limb. With a combination of conventional surgical and intraoperative endovascular procedures, thrombectomy and recanalization of the right iliac limb was completed by stenting a severe stenosis of the proximal iliac limb. CONCLUSIONS: A combination of techniques may be essential for successful management of thrombotic complications after endovascular AAA repair.

Acute Disease↗
PubMed1998

[The ABBI system as a possibility for evaluating non-palpable lesions].

For non-palpable lesions detected radiographically alone, lumpectomy after needle-localization is currently performed. Specimen radiography provides an indirect proof of complete excision of the mammographic abnormality. Up to now, intraoperative mammography of the operated breast has not been possible. Digital intraoperative mammography is now possible with the ABBI-system, which will be introduced in this article. In a pilot study, we have investigated, whether it is possible to excise small carcinomas with the ABBI stereotactic biopsy device (maximum diameter 20 mm) without compromising breast conserving therapy. In a prospective study, 69 patients were diagnosed or treated using the ABBI-system. In all 60 patients with a primary lesion, a cylindrical excision was performed. Of these, 11 invasive and 5 intraductal carcinomas were diagnosed. 7 of the invasive and 2 of the intraductal cancers were treated with breast conserving surgery. In 9 cases, an in-breast recurrence was suspected. In 7 of these a cylindrical excision was performed. One invasive and 3 intraductal carcinomas were found and mastectomy was performed in these four patients. In two patients with the suspicion of an in-breast recurrence, the ABBI-system was used to perform a core-needle biopsy. In one patient, the biopsy finding was positive and mastectomy was performed. Patients with lesions close to the chest wall are not suited for the ABBI-system. The postoperative course was uneventful in all cases, the cosmetic result after breast-conserving therapy was very good. The advantages of this new method consist in the reliable stereotactic localization of suspicious lesions and in the fast intraoperative imaging.

Biopsy, Needle↗
PubMed1998

[Effect of splenectomy on intra- and extraperitoneal tumor growth with reference to the immune system in a rat model].

In this model, splenectomy does not significantly influence the intra- and extraperitoneal tumor growth. Although the spleen accounts 25% of the cellular immune capacity, we found no difference in pro- or antiinflammatory cytokines but a significant increase of the white blood count after splenectomy compared with the control group. The influence of splenectomy on growth of intraperitoneal disseminated tumor cells must be investigated in further studies.

Adenocarcinoma↗
PubMed1998

[Effect of intra-abdominal pressure in laparoscopy on intraperitoneal tumor growth and development of trocar metastases. An animal experiment study in the rat model].

The results of the study indicate that elevated pressure during gas incubation in vitro leads to suppression of tumor growth probably due to direct damage of the cells. In vivo, laparoscopy with carbon dioxide and slightly elevated intraperitoneal pressure (5 and 10 mmHg) leads to promotion of intraperitoneal tumor growth while higher pressure (15 mmHg) causes again suppression of intraperitoneal tumor growth. Subcutaneous tumor growth is stimulated by carbon dioxide insufflation in all groups with elevated intraperitoneal pressures. The hypothesis that elevated intraperitoneal pressure might influence the immune system of the tumor host and increase immune suppression after laparoscopy remains theoretically and has to be investigated in further studies.

Air Pressure↗
PubMed1998

[Surgical therapy of tumor embolism of the vena cava in renal cell carcinoma].

Radical nephrectomy (Nx) with vena caval thrombectomy represents the only realistic chance of cure for patients with renal cell carcinoma with extension into the vena cava inferior (VCI). For stage III, with tumor extension in the retrohepatic VCI up to the diaphragm, a venous bypass technique is described. From July, 1996 through April, 1998, Nx combined with thrombectomy of the VCI was performed by isolation of the VCI, temporary occlusion of the hepatoduodenal ligament, and temporary extracorporal femoral-axillary veno-venous bypass with the Biomedicus pump. Radical resection of tumor thrombus from the VCI was accomplished under direct vision with minimal blood loss and without cardiopulmonary complications. With a follow-up of 21, 16, 9, 2, and 1 months, respectively, all patients are so far free of complications and without recurrent or metastatic disease.

Carcinoma, Renal Cell↗
PubMed1998

[Stereotactic tumor biopsy and tumor excision].

Stereotactic procedures are indicated in nonpalpable breast lesions that are suspicious in mammography. Using the ABBI system all established procedures (stereotactic needle biopsy, fine needle biopsy, core needle biopsy) can be performed. Also the resection of cylindrical tissue specimen with a maximum diameter of 20 mm can be carried out, controlled by digital mammography. For the exact diagnosis of lesions with a diameter up to 15 mm, cylindrical extirpation is recommended. In several cases this can be considered as definitive lumpectomy. Neither lesions localized close to the thoracic wall nor retromamillary lesions can be treated by using the ABBI system. While digital mammography is the method of choice for the detection of microcalcifications, the visualization of opacifications may be difficult. Overall the ABBI system was used in 40.7% of our patients with nonpalpable breast lesions.

Biopsy, Needle↗
PubMed1998

[Effect of alanyl-glutamine in postoperative total parenteral nutrition on postoperative immunosuppression and morbidity. Preliminary results of a prospective randomized study].

The impact of glutamine substitution on postoperative immunosuppression and morbidity was investigated in patients with surgical interventions and total parenteral nutrition in a prospective randomized trial. To analyze immune competence, the expression of CD3, CD4, and CD8 on lymphocytes and of HLA-DR and CD14 on monocytes as well as the plasma levels of IL-6 and IL-10 was evaluated before, 1, 2, 4, and 7 days after surgery. A total of 34 patients have been included (with glutamine: n = 18; without glutamine: n = 16). Patients with glutamine substitution showed decreased systemic inflammation, significant faster compensation for postoperative immunosuppression and a lower incidence of postoperative complications. Patients without postoperative complications showed no significant differences in postoperative immunosuppression.

Adult↗
PubMed1998

[Immune stimulation with G-CSF (Neupogen) in septic patients with immune paralysis].

Ten patients with sepsis (HLA-DR+ monocytes < 30%) were treated with G-CSF (300 mg Filgrastin, Neupogen 30, Amgen). All patients showed a rise in HLA-DR+ monocytes during therapy. In six patients the high level of HLA-DR+ monocytes persisted after therapy; these patients survived. In the other four patients the number of HLA-DR+ monocytes declined after application of G-CSF, and the patients died of multiorgan failure. Some patients with sepsis might profit from immunestimulating therapy with G-CSF, but further studies are needed to prove whether or not this is true.

Adjuvants, Immunologic↗
PubMed1998

[Hormone therapy of postoperative recurrent pancreatic carcinoma with octreotide and tamoxifen].

In a prospective trial a combination of octreotide and tamoxifen was evaluated for its effect on tumour recurrence of R0-resected pancreatic carcinoma. Compared to the control group (n = 14), which was treated according to "best supportive care", the median survival times for the octreotide-tamoxifen group (n = 14) were 7 and 3.5 months respectively. In the octreotide-tamoxifen group patients suffered less from nausea, pain and fatigue (p < 0.05). Furthermore, there was a benefit of octreotide-tamoxifen therapy for global life quality.

Adenocarcinoma↗
PubMed1998

[Does the pouch modify food transit after gastrectomy?].

A prospective, randomized study of patients with gastric cancer was performed to examine whether or not the jejunal pouch interposition between esophagus and duodenum after gastrectomy is of importance. At fixed postoperative times, standardized scintigraphic measurements were performed; the quality of life was evaluated by the EORTC quality of life questionnaire. Our findings suggest that interposition of a jejunal pouch reservoir between esophagus and duodenum may be due to a prolonged transit time and a better quality of life.

Duodenum↗
PubMed1997

Hypoxia induces c-fos transcription via a mitogen-activated protein kinase-dependent pathway.

Hypoxia is a pathophysiological condition that occurs during injury, ischemia, and stroke. It is characterized by a decrease of reactive oxygen intermediates and a change of the intracellular redox level. In tumors hypoxia is regarded as a trigger for enhanced growth and metastasis. Here we report that in HeLa cells, hypoxic conditions induce the transcriptional activation of c-fos transcription via the serum response element. Mutations in the binding site for the ternary complex factor Elk-1 and the serum response factor abolished this induction, indicating that a ternary complex at the serum response element is necessary for the induction of the c-fos gene under hypoxia. The transcription factor Elk-1 was covalently modified by phosphorylation in response to hypoxia. Furthermore this hyperphosphorylation of Elk-1, the activation of mitogen-activated protein kinase (MAPK), and the induction of c-fos transcripts were blocked by PD98059, a specific inhibitor of mitogen-activated protein kinase kinase/extracellular signal-regulated protein kinase kinase 1. An in vitro kinase assay with Elk-1 as substrate showed that MAPK is activated under hypoxia. The activation of MAPK corresponds temporally with the phosphorylation and activation of Elk-1. Thus, a decrease of the intracellular reactive oxygen intermediate level by hypoxia induces c-fos via the MAPK pathway. These results suggest that the intracellular redox levels may be directly coupled to tumor growth, invasion, and metastasis via Elk-1-dependent induction of c-Fos controlled genes.

Anaerobiosis↗
PubMed1997

Pentoxifylline reduces venular leukocyte adherence ("reflow paradox") but not microvascular "no reflow" in hepatic ischemia/reperfusion.

Postischemic reperfusion injury is caused by microcirculatory disturbances, including both nutritive perfusion failure (no reflow) and leukocyte activation (reflow paradox). Recent studies brought evidence that pentoxifylline (PTX) reduces tissue injury, decreases enzyme release, and improves survival after normothermic liver ischemia/reperfusion. The mechanisms of action, however, by which PTX protects postischemic tissue from injury have not been elucidated yet. With the use of fluorescence microscopy in a rat hepatic ischemia/reperfusion model, we studied in vivo the action of PTX on the manifestation of postischemic sinusoidal perfusion failure and microvascular leukocyte adherence. Microvascular reperfusion after 20 min portal triad cross-clamping was characterized by the cessation of blood flow within individual sinusoids (no reflow) and accumulation of leukocytes within the hepatic microvasculature, with stasis in sinusoids and rolling and firm adherence in postsinusoidal venules. PTX (20 mg/kg x hr i.v.) significantly (P < 0.05) attenuated microvascular leukocyte accumulation (44,600 +/- 1833 mm(-3) vs 67,684 +/- 2620 mm(-3) in saline-treated controls) and firm adherence of leukocytes in postsinusoidal venules (316.9 +/- 40.9 mm(-2) vs 522.9 +/- 95.0 mm(-2)); however, PTX did not influence manifestation of individual sinusoidal perfusion failure. Since reperfusion-induced parenchymal cell damage was found reduced in treated animals, we conclude that PTX attenuates postischemic injury in rat liver by reduction of leukocytic/inflammatory response but not by prevention of nutritive perfusion failure.

Animals↗
PubMed1997

Antioxidants as well as oxidants activate c-fos via Ras-dependent activation of extracellular-signal-regulated kinase 2 and Elk-1.

Intracellular reactive oxygen intermediate (ROI) levels play an important role in numerous physiological and pathophysiological conditions. Apart from causing oxidative stress and damage, ROI changes differentially activate gene expression. However the proto-oncogene encoding the AP-1 transcription factor subunit c-Fos is induced by both prooxidants and antioxidants. Here, the transcription factor Elk-1 is identified as being responsible for c-fos serum response element (SRE) induction in response to changes in the cellular redox status induced by treatment with either the oxidant H2O2 or various structurally unrelated antioxidants. A temporal correlation is observed between changes in the phosphorylation status of Elk-1 and the activation of the mitogen-activated protein kinase 2 (ERK2) in response to cellular redox changes. Correspondingly, the transcriptional response of the SRE to redox fluctuations is attenuated upon mutation of critical ERK2 target residues within the Elk-1 transactivation domain to alanine. Signals elicited by antagonistic intracellular redox changes converge at or above the level of Ras or an effector of Ras, leading to similar activation of c-fos transcription, since an [N17]Ras mutant interfered with redox signaling. Hence components of signaling pathways are revealed to be shared by mitogenic and redox-dependent stimuli.

Antioxidants↗
PubMed1997

Study of gene regulation by NF-kappa B and AP-1 in response to reactive oxygen intermediates.

Reactive oxygen intermediates (ROIs), such as hydrogen peroxide or superoxide, are an evolutionarily ancient threat to all organisms. Exposure of bacteria to ROIs initiates a genetic program that coordinates the production of novel proteins with protective functions. This genetic response is mediated by regulatory proteins that have the potential to initiate transcription of genes when the levels of the ROIs increase. In plant cells, a variety of viral pathogens increase hydrogen peroxide production, which is required to mount a defensive genetic response. It was suggested that in this case H2O2 is used as a secondary messenger and an immediate-early pathogen signal. In higher vertebrates, two transcription factors, nuclear factor kappa B and activator protein 1, were found to respond to ROIs. Both are well studied: they are induced by a great variety of seemingly unrelated conditions and serve important roles in immune, inflammatory, and other pathogen-related genetic responses. In this article we discuss how the ROI responsiveness of transcription factors can be experimentally studied and summarize evidence to suggest that ROIs have been conserved during evolution as messengers of a general pathogen response.

Animals↗
PubMed1997

Improvements in mechanical bowel preparation for elective colorectal surgery.

PURPOSE: This study was undertaken to determine whether a mechanical bowel preparation with 2 liters of polyethylene glycol solution combined with a laxative (Group A) increases the acceptability of bowel preparation and reduces discomfort compared with 4 liters of polyethylene glycol solution (Group B). METHODS: One hundred patients undergoing an elective colorectal resection were included in a prospective, randomized study. Acceptability (nausea, vomiting, abdominal cramps, discomfort from insertion of the nasogastric tube, and anal discomfort) was assessed using visual analog scales. Efficacy of bowel lavage was scored intraoperatively by a blinded surgeon. RESULTS: Overall acceptability was 5.1 +/- 2.8 in Group A patients and 5.6 +/- 2.6 in Group B patients (P = 0.5). The incidence and visual analog score for nausea, vomiting, anal discomfort, and cramps were not different between groups. Excellent efficacy of bowel preparation was shown in 94 percent of patients in Group A and 84 percent of patients in Group B (P = 0.5). The incidence of septic complications was 2 percent in Group A patients and 12 percent in Group B patients (P = 0.06). CONCLUSION: Because the acceptability of both cleansing regimens were not different, 2 liters of polyethylene glycol plus Prepacol should be preferred because the amount of fluid administered to clean the bowel is reduced and the nasogastric tube can always be avoided.

Aged↗