PubMed Health⌕ Search

Biomedical subjects

S Rohr

Publications and source records attributed to S Rohr.

At least 19 recordsLinked to original sources
PubMed2005

High-density electrode array for imaging in vitro electrophysiological activity.

The development of a high-density active microelectrode array for in vitro electrophysiology is reported. Based on the Active Pixel Sensor (APS) concept, the array integrates 4096 gold microelectrodes (electrode separation 20 microm) on a surface of 2.5 mmx2.5 mm as well as a high-speed random addressing logic allowing the sequential selection of the measuring pixels. Following the electrical characterization in a phosphate solution, the functional evaluation has been carried out by recording the spontaneous electrical activity of neonatal rat cardiomyocytes. Signals with amplitudes from 130 microVp-p to 300 microVp-p could be recorded from different pixels. The results demonstrate the suitability of the APS concept for developing a new generation of high-resolution extracellular recording devices for in vitro electrophysiology.

Animals↗
PubMed2005

[A urachus cyst revealing a torpid Crohn's disease in a young adult with chronic fever].

INTRODUCTION: This case report describes a rare situation in which a superinfected cyst of the urachus complicated initially unknown and inactive Crohn's disease. CASE: A 21-year-old man presented a chronic fever finally attributed to a superinfected urachal cyst. Six months after ablation of the cyst, progressive Crohn's disease was diagnosed. DISCUSSION: The association of Crohn's disease and a superinfected urachal cyst is extremely rare. The case reported here is original in two aspects: the slowly progressive Crohn's disease was diagnosed after its complication; the superinfection developed through local bacterial translocation (ileal loop adjacent to the urachal cyst).

Adult↗
PubMed2005

[The outcomes of laparoscopic fundoplication for gastro-oesophageal reflux disease. Long term results].

INTRODUCTION: The aim of this study was to evaluate the long term efficacy of laparoscopic treatment of gastroesophageal reflux disease (GERD). PATIENT AND METHODS: Between 1(st) January 1992 and 31 December 1996, 161 patients underwent complete or partial laparoscopic fundoplication for a symptomatic GERD. One hundred and twenty three patients were submitted to Nissen-Rossetti fundoplication, 26 patients to Nissen fundoplication and 12 patients to a partial posterior Toupet fundoplication.141 patients were evaluated at 3 months, 2-years and 5-years. Since undergoing the operation, four patients died of unrelated causes, 16 patients could not be contacted for follow up (10%). pH monitoring and oesophageal manometry were performed preoperatively and at 3 months postoperatively. The patients were evaluated 2 and 5-years after surgery by specific phone questionnaire. RESULTS: There was no mortality, the morbidity rate was 1.2% and the conversion rate was 5%. Incidence of dysphagia 3 months after surgery was 23.4%, and 5-years after 12%; 12% of patients had recurrent symptoms at 5 years. CONCLUSION: The overall satisfaction rate at 5 years was 91.4%. Nissen-Rossetti fundoplication seems to have better results at 5-years regarding postoperative dysphagia and symptoms recurrence.

Adult↗
PubMed2005

[Digestive surgery and varicose vein surgery].

The thromboembolic risk related to surgery may be considered as low for varicose vein surgery and non major digestive surgery. It could be defined as moderate in case of large dissection, long duration of procedures and emergency cases. The risk may be considered as high for major abdominal surgery involving cancer surgery or not and bariatric surgery. The absence of prophylaxis can be proposed for low risk surgery (grade B). However, elastic compression stocking are effective for all cases of digestive surgery and suggested to be used (grade A). There are no data concerning the moderate risk situation. Therefore, experts recommend the use of elastic compression stockings or low doses of LMWH (grade D). High-risk surgery requires the use of high doses of LMWH recommended for reasons of efficacy, tolerance, and easiness to use (grade A). Associated elastic stockings is efficious (grade B). The duration of prophylaxis lasts generally 7-10 days. Extension to 1 month is recommended for major abdominal cancer surgery (grade A).

Ambulatory Surgical Procedures↗
PubMed2004

[Colorectal stapled anastomosis: results after anterior resection of the rectum for cancer].

OBJECTIVE: Stapled end to end anastomosis makes the restoration of digestive continuity at the level of lower pelvis easier, but carries a certain risk. The aim of this report was to evaluate this risk in terms of immediate results and tumor recurrence after surgery for rectal cancer. PATIENTS AND METHODS: The data of 301 patients operated on following this technique between 1980 and 2000 have been reviewed in order to analyse the tumor characteristics, the operation and associated complications, the immediate postoperative complications and recurrence rate. RESULTS: Among the 301 patients (192 males and 109 females) with median age of 66 years, 19 (6.3%) received an emergency operation due to bowel obstruction. The rectal adenocarcinoma was located in the upper rectum in 132 cases (43.8%), in the middle rectum in 141 cases (46.8%) and in the lower rectum in 19 cases (9.4%). Preoperative radiotherapy was carried out in 148 cases (49%): between 1987 and 1996 with a dose of 30 Grays (Gy), later increased to 39 Gy and 45 Gy in 12 cases. From 1990, 113 patients have received adjuvant chemotherapy for stage III and IV tumors and in some position cases for stage II tumor. The excision left a safety margin under the tumor of less than 2 cm in 59 cases (19.6%), and the anastomosis was located at 5 cm or less from the anal verge in 178 cases (59%). Primary defunctioning stoma was formed in 39 cases (13%). An anastomotic defect was observed during the operation in 18 cases (6%) and 26 fistulas occured postoperatively (7.6%), significantly related to the location of the anastomosis with regard to the anal verge (P = 0.0009). The hospital mortality was 8 cases (2.6%). Cases of stenosis were uncommon : 11 cases (3.6%), significantly associated with preoperative radiotherapy (P =0.02). The local recurrence rate was 12% (37 cases) in a median time delay of 16 months, essentially related to the tumor stage (P = 0.004) and the considered period (P = 0.001). CONCLUSION: Stapled end-to-end colorectal anastomosis after excision of rectum for cancer is a reliable technique with a low rate of complication and tumor recurrence, when the surgical procedure is included in the curative therapy management of cancer.

Adenocarcinoma↗
PubMed2004

Retrospective study of laparoscopic adjustable silicone gastric banding for the treatment of morbid obesity: results and complications in 127 patients.

OBJECTIVES: Laparoscopic gastric banding is currently the most popular surgical technique for morbId obesity. This wIdespread use of surgery has been evaluated by a number of clinical studies, particularly on weight change. METHODS: In a retrospective study of 127 obese patients operated between 1996 and 2000, data were collected for weight change, medical and surgical complications. RESULTS: Of 127 patients, failures of gastric banding were noted during 2 surgical operations. The average follow-up period was 33 +/- 20 Months. Average weight loss in all patients was 19.9 +/- 5.3 kg (15.3 +/- 4.2%). No difference in weight loss was observed between diabetic and non-diabetic patients. During the follow-up, data were collected on 53 complications (42.4% of all gastric banding operations). 3 main types of complication were found: access port related complications (22.6% of the total), band slippage (20.7% of the total) and tubing related complications (16.9% of the total). No prognostic factor for these complications could be Identified from multivariate analysis. CONCLUSIONS: Our results are very similar to those of other weight evolution studies. We found that there was a significant incIdence of surgical and medical complications during the follow-up because of the meticulous way all complications were recorded, even the most insignificant. This morbIdity must be borne in mind before surgery is performed.

Adult↗
PubMed2004

Expression of endothelial and inducible nitric oxide synthases is modulated in the endometrium of cyclic and early pregnant mares.

The expression of the endothelial and inducible nitric oxide synthases (eNOS and iNOS, respectively) was examined in the endometrium of cyclic and pregnant mares by real-time polymerase chain reaction and immunohistology. The concentration of eNOS mRNA varied throughout the oestrous cycle, with significantly higher transcripts on Day 5 of the oestrous cycle (P < 0.05), whereas iNOS transcription did not change significantly over time (P > 0.05). In early pregnant mares both eNOS and iNOS mRNA increased between Days 12 and 15 (P < 0.05). In cyclic mares, eNOS protein was detected immunocytochemically in endometrial epithelia, the basement membrane, the endothelial layer and smooth muscle cells of the vasculature. Using immunocytochemical methods, iNOS protein was undetectable in the endometrium of cyclic mares but could be demonstrated in pregnant mares. Endometrial epithelia of pregnant mares were immunopositive for both proteins with a more intense labelling for iNOS. Thus, the present study describes for the first time the modulation and spatial distribution of eNOS and iNOS expression during the oestrous cycle and early pregnancy, suggesting that ovarian steroids are differently involved in the regulation of each NOS. Localisation of eNOS protein in endometrial epithelia and various vascular components indicates that this isoform may be involved in the regulation of endometrial cyclicity. The presence and increase of both forms of NOS during early gestation suggest a role for them in the control of endometrial vascular bed and glandular activity to provide a suitable microenvironment for successful pregnancy.

Animals↗
PubMed2003

[Gastroplasty: complications and their prevention].

Bariatric surgery is now frequently proposed for the treatment of morbid or complicated obesity since the introduction of minimally invasive laparoscopic anti-obesity operations such as the adjustable silicone gastric binding gastroplasty. However this reversible procedure in not always as safe as presumed and the results in weight loss may be sometimes disappointing. Side effects are common and early or late complications occured in more than 20% out of the patients. They are favoured by post operative eating disorders. Nutritional consequences are probably underestimated and are not limited to uncomfortable digestive symptoms. Some deficiencies in micronutriments have been described. The worsening of previous eating disorders or psychosocial abnormalities are not seldom. Gastroplasty is not an harmless procedure. A good selection in patients, a regular follow up, nutritional advices and psychosocial management by a multidisciplinar team are required to reduce complications after gastroplasty.

Gastroplasty↗
PubMed2002

[Interest in intestinal resection for treatment of advanced ovarian cancer].

AIM OF THE STUDY: Digestive surgery is often necessary for surgical management of advanced ovarian carcinoma. PATIENTS AND METHODS: In a series of 62 patients with stage III ovarian carcinoma, postoperative morbidity and mortality, overall survival after 5 years and disease-free survival after 2 years were studied and corelated with several patients criteria (age, stage of the disease, residual disease, type of surgery, CA125 normalisation delay, postoperative complications and hospital stay). Patients were divided into two groups according to the surgical treatment. The first group (n = 17) included patients treated by gynecologic and digestive surgery, the second group (n = 45) included patients treated by gynecologic surgery only. All patients were proposed for chemotherapy included platyn salt. Mean age was 60 years (range: 20-83). The stage of the cancer was stage IIIa in 7 cases, stage IIIb in ten and stage IIIc in 45. RESULTS: Postoperative mortality was 3.5% (2/62). Postoperative morbidity was 26% (13/62). No statistical differences were noted for hospital stay, general morbidity, surgical morbidity when a gastric resection or a colon resections or a splenectomy were performed. Overall survival at 5 years was 56%. Residual disease less than 2 cm3 is the only prognostic factor for overall survival (56% vs 23% [P = 0.03]) and disease-free survival (86% vs 46% [P = 0.02]). CONCLUSION: This study including 62 patients confirmed the prognostic significance of extensive cytoreductive surgery for treatment in advanced ovarian epithelial cancer without increasing the postoperative morbidy and mortality.

Adult↗
PubMed2002

[Laparoscopic treatment of large hiatal hernias using a prosthesis. Report of ten cases].

OBJECTIVE: To evaluate prospectively the laparoscopic surgery for giant hiatal hernias treated by fundoplication and hiatal prosthesis. PATIENTS AND METHODS: Ten patients were included in this study. Surgical technic included the dissection of oesophageal hiatus, the sac excision and the dissection of the abdominal oesophagus to obtain a physiological length. The decision criterion for a prosthesis was the hiatus oesophagus diameter of 5 cm or more. The crura were closed and the hiatus was reinforce by a prosthesis of 15 x 15 cm. All patients underwent a fundoplication whether partial or complete. RESULTS: Eight patients had a type III hernia, and 2 had a type II. The mean size for the hiatus was 6.5 cm (5.5-8). Eight patients underwent a total fundoplicature and 2 a partial one. The prosthesis was made of polypropylene in 5 cases. Average operating time was 182 min (78-240). One patient had postoperative morbidity, with gastroplagia which resolved. There was no mortality. Mean hospitalisation duration was 7.7 days (5-12). No one case of recurrence have been noticed after a mean follow-up of 24 months (8-40). CONCLUSION: It appears that the large size hiatal hernia (more than 5 cm) can be treated with good results by using a prosthesis during laparoscopic fundoplication.

Aged↗
PubMed2001

Long-term recurrence after laparoscopic surgery of inguinal hernias.

Laparoscopic treatment of inguinal hernias has expanded rapidly during the last decade. Several studies have evaluated the early results of this technique, and the rate of recurrence was estimated less than 5% with a range from 0.5% to 10%. The long-term recurrence after such treatment is still not well known. This study reports the 2 year follow-up of laparoscopic treatment of 236 inguinal hernias (220 patients) from January 1996 to December 1997. All patients were contacted by telephone, 196 (90%) (193 men and 3 women) were examined by a senior surgeon. The average time from operation to examination was 34 months (range 20-42 months). We observed a 15% recurrence rate (35 hernias in 34 patients) of which 5% (12 cases) were symptomatic but 10% (23 cases) were totally asymptomatic and diagnosed on clinical examination. The postoperative inguinal haematoma and the physical activity of the patients seem to predispose the recurrence. Chronic pain was rarely observed in this study.

Adult↗
PubMed2001

Pancreatic metastasis of alveolar soft-part sarcoma: a case report and review of the literature.

Alveolar soft-part sarcoma is a rare tumour. Patients commonly present with distant metastases both at the time of diagnosis and late in the course of disease. We present a case of pancreatic metastasis, occurring more than six years after diagnosis. Treatment consisted in subtotal pancreatoduodenectomy with pylorus resection. Both specific patterns of relapse and treatment opportunities of this uncommon feature are discussed.

Adult↗
PubMed2001

Slow conduction in cardiac tissue: insights from optical mapping at the cellular level.

Under physiological conditions, slow conduction is essential for the function of the atrioventricular (AV) node, whereas, under pathophysiological conditions, slow conduction contributes importantly to the generation of life-threatening reentrant arrhythmias. This article addresses characteristics of slow conduction at the cellular network level during (a) a reduction of excitability, (b) a reduction of gap junctional coupling, and (c) in the setting of branching tissue structures. Microscopic impulse propagation in these settings was studied by using multiple site optical recording of transmembrane voltage in conjunction with patterned growth cultures of neonatal rat ventricular myocytes. In linear cell strands, a reduction of excitability slowed conduction by approximately 70% before block occurred. In contrast, critical reduction of gap junctional coupling induced a much higher degree of slowing (>99%) before block of conduction. Interestingly, a similar degree of conduction slowing was also observed in branching tissue structures under conditions of reduced excitability (98%). The finding of extremely slow but nevertheless safe conduction in these structures might be explained by a "pull and push" effect of the branches: by drawing electronic current from the activation wavefront, they first act as current loads which slow conduction at the branch points ("pull" effect). Then, on activation, they turn into current sources which feed current back into the system, thus supporting downstream activation and enhancing the safety of propagation ("push" effect). This "pull and push" mechanism may play a significant role in slow conduction in the AV node and in structurally discontinuous myocardium, such as the border regions of infarct scars.

Action Potentials↗
PubMed2001

Analysis of allelic imbalance in patients with colorectal cancer according to stage and presence of synchronous liver metastases.

OBJECTIVE: To investigate the relationship between number and location of allelic imbalances (AI) and local tumor progression according to Astler-Coller classification. SUMMARY BACKGROUND DATA: Spontaneous errors in DNA replication (i.e., allelic imbalance or microsatellite instability) have been suggested to play an important role in carcinomatous transformation as reflecting alterations of gene function. METHODS: One hundred two consecutive patients with colorectal carcinoma undergoing surgical resection were included in this study. Patients were distributed according to the Astler-Coller classification as stages A (n = 7), B1 (n = 15), B2 (n = 24), C (n = 31), and D (n = 25). Fluorescent polymerase chain reaction was performed on frozen tumor, normal colon mucosa, and blood DNA at 35 microsatellite markers. Allelic imbalance frequency was compared with tumor staging. RESULTS: The percentage of AI was significantly higher in stage D than in A/B1 and B2. In addition, the percentage of AI was significantly higher in 10 synchronous colorectal liver metastases than in stage A/B1 and B2 tumors. However, the allelotyping revealed a subgroup of A/B1 tumors with a high AI frequency. Statistical analysis showed that the presence of AI at microsatellites D1S305, D2S138, D3S1282, D17S790, and D22S928 presented a significantly positive correlation with stages. CONCLUSION: The frequency of AI significantly correlates with tumor progression of colorectal cancer. Primary tumors with synchronous colorectal liver metastases showed a higher percentage of AI, suggesting that a frequency of AI greater than 35% with this selection of markers indicates a high risk of local progression and of development of metastases.

Adult↗
PubMed2000

Power-law behavior of beat-rate variability in monolayer cultures of neonatal rat ventricular myocytes.

It is known that extracardiac factors (nervous, humoral, and hemodynamic) participate in the power-law behavior of heart-rate variability. To assess whether intrinsic properties of cardiac tissue might also be involved, beat-rate variability was studied in spontaneously beating cell cultures devoid of extracardiac influences. Extracellular electrograms were recorded from monolayer cultures of neonatal rat ventricular myocytes under stable incubating conditions for up to 9 hours. The beat-rate time series of these recordings were examined in terms of their Fourier spectra and their Hurst scaling exponents. A non-0 Hurst exponent was found in 21 of 22 preparations (0.29+/-0.09; range, 0.11 to 0.45), indicating the presence of fractal self-similarity in the beat-rate time series. The same preparations exhibited power-law behavior of the power spectra with a power-law exponent of -1.36+/-0.24 (range, -1.04 to -1.96) in the frequency range of 0.001 to 1 Hz. Furthermore, it was found that the power-law exponent was nonstationary over time. These results indicate that the power-law behavior of heart-rate variability is determined not only by extracardiac influences but also by components intrinsic to cardiac tissue. Furthermore, the presence of power-law behavior in monolayer cultures of cardiomyocytes suggests that beat-rate variability might be determined by the complex nonlinear dynamics of processes occurring at the level of the cellular network, eg, interactions among a large number of cell oscillators or metabolic regulatory systems.

Animals↗
PubMed2000

Mechanism of ventricular defibrillation. The role of tissue geometry in the changes in transmembrane potential in patterned myocyte cultures.

BACKGROUND: The geometry of the myocardium may influence changes in transmembrane potential (DeltaVm) during defibrillation. To test this hypothesis, specific nonlinear structures (bifurcations, expansions, and curved strands or "bends") were created in patterned cultures of neonatal rat myocytes. METHODS AND RESULTS: Extracellular field stimuli (EFS; 7 to 11 V/cm field strength) were applied parallel to the strands. Changes in Vm were measured with microscopic resolution using optical mapping techniques. In bifurcations, EFS produced 2 DeltaVm maxima (so-called secondary sources) at the shoulder of each limb that were separated by a decrease of either hyperpolarization or depolarization at the insertion of the stem strand. In expansions, EFS produced a significant decrease in DeltaVm at the insertion site of the expansion compared with the DeltaVm maxima measured at the lateral borders. In 50% of experiments, tertiary sources of opposite polarity appeared in the strand due to local electrotonic currents. New action potentials were propagated from the sites of DeltaVm maxima located at the lateral borders of the expansions. In bends, the strand oriented in parallel to the field dominated electrotonically and partially cancelled the sources produced by the perpendicular segment. CONCLUSIONS: In electrically well-coupled nonlinear structures, EFS produced changes in Vm at resistive boundaries that were determined by the electrotonic interaction between sources of different, direction-dependent strength. In addition, the interaction between localized secondary sources at nonlinear boundaries generated local current circuits, which gave rise to further changes in Vm (tertiary sources).

Animals↗
PubMed2000

Microsatellite instability and allelic imbalance in primary and secondary colorectal cancer.

BACKGROUND: Several studies of colorectal cancer have shown an association between the number and type of genomic defects and the stage of disease. A subset of colorectal tumours are due to inactivation of DNA mismatch repair genes and these tumours exhibit microsatellite instability. The aim of the present study was to compare and contrast the genomic defects present in both the primary and metastatic stages of the disease using microsatellite probes. METHODS: Modifications of the allelic profiles of 25 microsatellite regions were studied in a total of 85 colorectal tumours using fluorescent polymerase chain reaction (PCR) technology and subsequent direct analysis on an automatic sequencer. This approach was used because it allows the study of microsatellite instability and allelic imbalance. Stepwise logistic regression analysis was used to develop a model to predict whether the tumour was primary or secondary from the percentage of allelic imbalance. Subsequently, a group of 17 patients with primary colorectal tumours was analysed prospectively to test the proposed model. RESULTS: Six of 39 primary tumours showed microsatellite instability compared to 0 of 29 liver metastases (P = 0.03). Primary tumours showed significantly less allelic imbalance than liver metastases (P < 0.001). Three probes (d18s53, d9s158 and d10s191) were selected for use in a model to classify a tumour as primary or secondary on the basis of the degree of allelic imbalance. When tested prospectively this model had a specificity of 82%. CONCLUSIONS: The present study demonstrates the potential importance of using microsatellite probes both as a diagnostic tool and as a research technique to investigate the mechanisms of tumour progression. An important clinical finding is that none of the colorectal liver metastases showed microsatellite instability (0 of 29). This analysis also confirmed other work that has shown a direct relationship between the degree of allelic imbalance and the stage of disease.

Alleles↗