Biomedical subjects

U Guller

Publications and source records attributed to U Guller.

7 recordsLinked to original sources

PubMed2006

Propensity scores and the surgeon.

BACKGROUND: Evidence-based surgery has been established as a cornerstone of good clinical practice, promising to improve the treatment of patients and the quality of surgical education. However, evidence-based surgery requires dedicated clinicians trained to perform methodologically sound clinical investigations. Statistical knowledge is therefore invaluable. Surgical studies often cannot be randomized. Propensity scores offer a powerful alternative to multivariable analysis in the assessment of observational, non-randomized surgical studies. Unfortunately, many surgeons are unaware of this important analytical approach that has gained increasing stature in medical research. Thus, propensity score analyses are not used often in surgical studies. OBJECTIVE: The purpose of this paper is to provide a comprehensive overview of propensity score analysis, allowing the surgeon to understand the role, advantages and limitations of propensity scores, boosting their development in surgical investigations.

Confounding Factors, Epidemiologic↗

PubMed2005

Long-term outcomes of breast cancer patients after endoscopic axillary lymph node dissection: a prospective analysis of 52 patients.

BACKGROUND: Reports on long-term outcomes after endoscopic axillary lymph node dissection (ALND) of breast cancer patients are still lacking in the medical literature. The objective of this prospective study was to assess the oncological and functional outcomes in breast cancer patients after endoscopic ALND. METHODS: Fifty-five breast cancer patients were prospectively enrolled, of whom 52 were available for follow-up with a median of 71.9 months (range 11-96). The following oncological and functional endpoints were evaluated during follow-up at several time points: occurrence of local, axillary and distant metastases, seroma or infection, shoulder mobility (range of motion), numbness, pain, presence of lymphoedema as well as restriction in activities of daily living. RESULTS: In 52 patients endoscopic ALND of level I and II was successfully performed. Two port-site metastases (2/52, 4%) occurred, one of which in a patient with negative axillary lymph nodes. The same patient suffered from the only axillary recurrence (1/52, 2%). Three patients (3/52, 6%) developed lymphoedema. No other functional adverse events (shoulder mobility, pain, numbness, hypertrophic scar) were noticed at the end of the observation period. CONCLUSION: The present investigation with long-term follow-up after endoscopic ALND--the first one in the literature--reveals minor morbidity, good functional and cosmetic results. In contrary to conventional surgery, the endoscopic procedure is associated with the occurrence of port-site metastases, not seen in the open approach. Axillary recurrences do not appear more frequently when compared with results after conventional ALND. In the meantime the less invasive sentinel lymph node (SLN) biopsy is the established standard technique in evaluating the axillary lymph node status.

Activities of Daily Living↗

PubMed2003

Phase I/II clinical trial of a nonreplicative vaccinia virus expressing multiple HLA-A0201-restricted tumor-associated epitopes and costimulatory molecules in metastatic melanoma patients.

We performed a phase I/II clinical trial in metastatic melanoma patients with an ultraviolet (UV)-inactivated nonreplicating recombinant vaccinia virus enabling the expression, from a single construct, of endoplasmic reticulum-targeted HLA-A0201-restricted Melan-A/MART-1(27-35), gp100(280-288), and tyrosinase(1-9) epitopes, together with CD80 and CD86 costimulatory proteins. Corresponding soluble peptides were used to boost responses and granulocyte-macrophage colony-stimulating factor was used as systemic adjuvant. Safety and immunogenicity, as monitored with in vitro-restimulated peripheral blood mononuclear cells by cytotoxic T lymphocyte precursor (CTLp) frequency analysis and tetramer staining, were specifically addressed. Of 20 patients entering the protocol, 2 had to withdraw because of rapidly progressing disease. Immune responses were evaluated in 18 patients (stage III, n = 5; stage IV, n = 13) and increases in specific CTLp frequencies were observed in 15. In 16 patients responsiveness against all 3 antigens could be analyzed: 7 (43%), including all stage III cases, showed evidence of induction of CTLs specific for the three epitopes, and 2 (12%) and 4 (25%), respectively, showed reactivity against two or one tumor-associated antigen. In three stage IV patients no specific CTL reactivity could be induced. Increases in CTLp frequency were detected mostly after viral vaccine injections. However, in a majority of patients final CTLp levels were comparable to initial levels. Tetramer characterization of Melan-A/MART-1(27-35)-specific CTLs during the protocol also suggested preferential expansion after recombinant virus administration. Vector-specific humoral responses, frequently undetectable in stage IV patients, did not appear to prevent tumor-associated antigen-specific CTL induction. Aside from a single occurrence of transient grade 3 leukopenia, no major clinical toxicity was reported. Seventeen of 18 patients completed the 3-month trial (one patient died before the last delayed-type hypersensitivity test). Three displayed regression of individual metastases, seven had stable disease, and progressive disease was observed in seven patients. This is the first report on the administration of a UV-inactivated recombinant vaccinia virus coexpressing five transgenes in cancer patients. The results described here, in terms of safety and immunogenicity, support the use of this reagent in active specific immunotherapy.

Adult↗

PubMed2003

Statistics in medicine.

Explore the source record for details and available documents.

Data Interpretation, Statistical↗

PubMed2003

Perioperative detection of disseminated tumour cells is an independent prognostic factor in patients with colorectal cancer.

BACKGROUND: The objective of the present investigation was to assess the prognostic significance of disseminated tumour cells in peritoneal lavage, and peripheral and mesenteric venous blood in patients undergoing curative resection of colorectal cancer. METHODS: The prognostic impact of perioperative cytological and immunocytochemical detection of disseminated colorectal cancer cells was evaluated prospectively. Peritoneal lavage fluid, and peripheral and mesenteric venous blood from 53 consecutive patients undergoing curative surgery for colorectal cancer were analysed. The dichotomous results (positive versus negative) from the cytological and immunocytochemical analysis were used as a predictor along with other co-variates in proportional hazard regression models of disease-free and overall survival. RESULTS: Disseminated colorectal cancer cells were found in 13 of 53 patients (25 per cent) using cytology (CYT) and/or immunocytochemistry (ICC). The median follow-up at the time of the analysis was 37 months. In multivariate proportional hazard regression models CYT/ICC status was a significant predictor for disease-free (P = 0.002) and overall (P = 0.006) survival. CONCLUSION: Disseminated tumour cells detected by CYT and ICC represent an independent prognostic factor in patients undergoing surgery for colorectal cancer and may identify patients at high risk of recurrence.

Adult↗

PubMed2001

[Intravascular detection of myocardial ischemia by spectrometry in the near infrared spectrum in experimental animals].

Interruption of oxygen supply in acute myocardial ischaemia reduces venous return of oxygen at the coronary sinus. In this study, the oxygen content of venous return in the coronary sinus was measured by using spectrometry in the near infrared spectrum. The authors developed a new intravascular catheter made of fibre optics. After in vitro calibration by blood flow based on a standard gas mixture used in in vitro experiment, an in vivo application in 12 domestic pigs was undertaken. The catheter was positioned in the coronary sinus and ischaemia induced by temporary occlusion of the left anterior descending artery. Recordings of the near infrared spectrum and haemodynamic data were obtained during 90 minutes' ischaemia followed by 90 minutes reperfusion. Spectrometry in the near infrared range detected a marked difference between oxyhaemoglobin and deoxyhaemoglobin, especially when the oxygen concentration was less than 30%. The near infrared spectrum of liaison between haemoglobin and oxygen in the coronary sinus shows significant and reproducible differences between pre-ischaemia occlusion of the left anterior descending artery and reperfusion. The recordings of the near infrared also show variation in CO2, pH and temperature. The authors conclude that the use of intravascular spectrometry of the near infrared spectrum could be a permanent reliable tool for detection and follow-up of acute myocardial ischaemia.

Animals↗

PubMedDate not supplied

Expression of MAGE-A cancer/testis antigens in esophageal squamous cell carcinomas.

BACKGROUND: Although the diagnosis and therapy of esophageal cancer have improved over the past decade, the prognosis remains dismal. Since MAGE-A cancer/testis antigens (CTA) are potential targets for immunotherapy, this study was aimed at evaluating their expression in these patients and its prognostic value. MATERIALS AND METHODS: Using 57B monoclonal antibody, MAGE-A CTA expression was analyzed in paraffin-embedded tumor specimens of 98 patients with esophageal squamous cell carcinoma or adenocarcinomas who had undergone surgical resection. For all patients, a postoperative follow-up of at least 4 years was available. The expression was quantified using a scoring system considering intensity and homogeneity of the immunostaining. The prognostic relevance of MAGE-A expression was analyzed in univariate analyses as well as Cox proportional hazard regression analysis. RESULTS: 57B positivity could be detected in 38 tumors (38.8%). Positive staining was observed in five out of 32 adenocarcinomas (15.2%) and in 33 out of 66 (50%) squamous cell carcinomas. MAGE-A expression did not correlate with the TNM classification, grading or age of the patients. Both univariate (p=0.88) and multivariate analyses (p = 0.82) revealed that MAGE-A expression lacked prognostic significance in esophageal carcinomas. CONCLUSION: MAGE-A was expressed in half of the squamous cell carcinomas of the esophagus, but rarely in adenocarcinomas. Although its immunodetection was insufficient for prognostic evaluation, the high expression rate suggests MAGE-A as a potential target for immunotherapy in the first group with the ability for pretherapeutic testing.

Adult↗