Search PubMed⌕ Search

Biomedical subjects

C Langer

Publications and source records attributed to C Langer.

At least 55 records · Page 3Linked to original sources
PubMed2002

Trapped-ion quantum simulator: experimental application to nonlinear interferometers.

We show how an experimentally realized set of operations on a single trapped ion is sufficient to simulate a wide class of Hamiltonians of a spin-1/2 particle in an external potential. This system is also able to simulate other physical dynamics. As a demonstration, we simulate the action of two nth order nonlinear optical beam splitters comprising an interferometer sensitive to phase shift in one of the interferometer beam paths. The sensitivity in determining these phase shifts increases linearly with n, and the simulation demonstrates that the use of nonlinear beam splitters (n=2,3) enhances this sensitivity compared to the standard quantum limit imposed by a linear beam splitter (n=1).

Journal Article↗
PubMed2002

Mesh penetration of the sigmoid colon following a transabdominal preperitoneal hernia repair.

The laparascopic transabdominal preperitoneal (TAPP) repair of an inguinal hernia is an established technique associated with notably low rates of recurrence and complication. Inguinal pain and anal bleeding following a TAPP procedure may result from the penetration of the repair mesh into the sigmoid colon. In this case report, we discuss this particular complication following the TAPP procedure. Subsequently, we describe the diagnostics as well as the surgical treatment necessary.

Colon, Sigmoid↗
PubMed2002

[Simulation of surgical techniques in graduate education of the surgeon. An analysis of value and effect].

The course in Gastrointestinal Surgery (GISC) aims at teaching and training resection, reconstruction and suture techniques of the upper gastrointestinal tract. Prior to, after and 5 years following the first course, participants were asked to answer a questionnaire requesting information regarding the adequacy of surgical training in their residency program and how much they had benefited from the GISC. While 1/3 of the participants described the surgical training during their residency as inadequate, more than 90% benefited from the GISC. Although the single-layer-continuous suture technique was implemented by only 8% of the participating surgeons, other techniques such as cross-section gastroenterostomy were accepted by 38%. Only 7% of the participants rejected these new techniques, while 41% of the senior surgeons at home could not be convinced. Besides the teaching of new techniques, participants benefited above all from the repetitive training in surgical procedures.

Animals↗
PubMed2002

[The carcinogenic potential of biomaterials in hernia surgery].

The implantation of meshes to correct inguinal as well as incisional hernias is widely used in the U.S.A. and Western Europe. The short and long term results of meshes are convincing concerning complications, recurrence rate and patient's comfort. On the other hand side some scientific groups discuss the possibility of malignant tumor development due to implanted meshes. In fact, experimental models exist which demonstrate that soft tissue sarcomas can be induced in mice and rats by implanting artificial materials such as synthetics or metal. Beside millions of hernia repairs using meshes worldwide no patient has been reported with a soft tissue tumor until today. The analyses of molecular markers of proliferation, of apoptosis as well as the modulation of heat shock proteins seem not to prove the carcinogenic potential of meshes. In conclusion, there are no data so far indicating a real risk for humans to develop malignant tumors due to implanted meshes. Therefore we further propagate the implantation of meshes in hernia repair in adult patients.

Adult↗
PubMed2002

Transanal endoscopic microsurgery (TEM) for minimally invasive resection of rectal adenomas and "Low-risk" carcinomas (uT1, G1 - 2).

Transanal endoscopic microsurgery (TEM) presents a minimally invasive procedure for local removal of large rectal adenomas (>/= 2 cm) and early, so called "low-risk" carcinomas (uT1, G1 - 2) in curative as well as of advanced tumors in palliative intent. Over a 6-year period 92 TEM excisions of rectal tumors were carried out including 91 patients with 56 adenomas, 35 carcinomas (9 pTis, 17 pT1, 5 pT2, 3 pT3, 1 Ca after snare diathermy) and one neurinoma. Two patients of the carcinoma group had to be reoperated by means of anterior resection due to false preoperative rectal ultrasound examination (2 x uT1--> pT2). 4 patients required palliative therapy on account of age or high morbidity. After a mean follow-up time of 23 months (adenomas 23 months, pT1 carcinoma 26 months and advanced tumors 38 months) we encountered a total of 7 complications, of which in 5 cases surgical reintervention was necessary (5,4 %). One 86-year-old patient with a pT2-carcinoma, who was unsuitable for low anterior resection due to a high morbidity risk, died from myocardial infarction after emergency reintervention caused by postoperative bleeding. To date, overall 9 recurrences occurred (9,8 %). In the specific target group of TEM (adenomas and pT1, G1-2 carcinomas) consisting of n = 83 cases, the overall recurrence rate was 7,2 %, of which 5,3 % were due to adenomas and 11,5 % due to carcinomas. After palliative excision 2 recurrences occurred. These results of transanal endoscopic microsurgery (TEM) indicate that this technique has a useful place in curative, as well as in palliative management of rectal tumors.

Adenoma↗
PubMed2001

Outcome of patients with a performance status of 2 in Eastern Cooperative Oncology Group Study E1594: a Phase II trial in patients with metastatic nonsmall cell lung carcinoma .

BACKGROUND: Eastern Cooperative Oncology Group (ECOG) Study E1594 compared paclitaxel and cisplatin with three newer chemotherapy doublets in the treatment of patients with advanced nonsmall cell lung carcinoma (NSCLC). The accrual of patients with an ECOG performance status (PS) of 2 was discontinued due to a perceived rate of unacceptable toxicity. METHODS: Patients were stratified by PS and randomized to one of the following treatments: 1) paclitaxel (135 mg/m2) over 24 hours with cisplatin (75 mg/m2) on a 21-day cycle; 2) cisplatin (100 mg/m2) with gemcitabine (1 g/m2) on Days 1, 8, and 15 on a 28-day cycle; 3) cisplatin (75 mg/m2) with docetaxel (75 mg/m2) on a 21-day cycle; and 4) paclitaxel (225 mg/m2) over 3 hours with carboplatin (area under the curve, 6). All tests of statistical significance were two-sided. RESULTS: Sixty-eight patients with an ECOG PS of 2 were enrolled, and 64 patients were evaluable for toxicity and response. Fifty-six percent of 64 evaluable patients were male, and 81% had Stage IV disease. Grade 3-4 hematologic toxicities occurred in > 50% of the patients in each treatment group. Nonhematologic Grade 3-4 toxicities occurred significantly less often in the paclitaxel and carboplatin arm (P = 0.0032). The overall rate of toxicity did not differ significantly from the rate of toxicity in the PS-0 or PS-1 cohorts. There were 5 deaths (7.35%) among 68 patients with a PS of 2 during therapy; however, only 2 of those deaths were attributed to therapy. The overall response rate for the 64 evaluable patients was 14%. The overall median survival of all 68 patients with a PS of 2, as determined by an intent-to-treat analysis, was 4.1 months. CONCLUSIONS: Patients with advanced NSCLC and a PS of 2 experienced a large number of adverse reactions and overall poor survival. A comparison with patients with a PS of 0-1 suggests that these events and the shorter survival were related to disease process rather than treatment. Alternative strategies need to be explored with therapy specifically tailored for this group of patients.

Aged↗