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Biomedical subjects

R Keller

Publications and source records attributed to R Keller.

At least 19 recordsLinked to original sources
PubMed2006

Xenopus fibrillin is expressed in the organizer and is the earliest component of matrix at the developing notochord-somite boundary.

We identify a Xenopus fibrillin homolog (XF), and show that its earliest developmental expression is in presumptive dorsal mesoderm at gastrulation, and that XF expression is regulated by mesoderm-inducing factors in animal cap assays. XF protein is also first detected in presumptive mesoderm, but is concentrated specifically into extracellular-matrix structures that begin to develop de novo by mid-gastrulation at both of the bilateral presumptive notochord-somite boundaries. Later in embryogenesis, XF protein is localized to the extracellular matrix at tissue boundaries, where it is found surrounding the notochord, the somites, and the neural tube, as well as under the epidermis. This pattern of protein deposition combines to give the appearance of an "embryonic skeleton," suggesting that one role for XF is to serve as a mechanical element in the embryo prior to bone deposition.

Amino Acid Sequence↗
PubMed2006

[Diagnostic laparoscopy in acute abdomen].

Acute abdomen is not a disease in itself but a description of a complex of symptoms combined with severe abdominal pain developed within a time frame of less than 24 h. All strategies for the management of acute abdomen underline the need for an interdisciplinary approach to diagnosis and therapy. This requires focused and intelligent use of efficient diagnostic procedures. Diagnostic laparoscopy may be a key to solving the diagnostic dilemma of unspecific acute abdomen. Furthermore, it allows not only direct inspection of the abdominal cavity but also surgical intervention, if needed. In particular the rate of negative laparotomies can be reduced.

Abdomen, Acute↗
PubMed2006

Alkaline and acid hydrolytic processes in aerobic and anaerobic sludges: effect on total EPS and fractions.

Sludge samples from an upflow anaerobic sludge blanket (UASB) reactor and four submerged aerated biofilters (BFs) of a wastewater treatment plant (1,000 inhab.) were processed at bench scale by alkaline and acid hydrolysis with the objective to evaluate the organic matter solubilization, volatile solids (VS) destruction and the effect of hydrolytic processes on the extracellular polymeric substances (EPS) fraction of the sludge samples. The results showed that alkaline hydrolysis of sludge samples treatment with 1.0% total solids (TS) using NaOH 20 meq L(-1) was more efficient on organic matter solubilization and VS destruction than acid hydrolysis. The EPS sludge content was also affected by the alkaline treatment of anaerobic sludge samples. The EPS concentrations (mg EPS/gVSS) on the anaerobic sludge after the alkaline treatment were significantly lowered according to sample height in the UASB reactor. Data indicated that the EPS sludge fraction is the main component affected by the alkaline hydrolytic process of anaerobic sludge samples.

Acids↗
PubMed2005

[Comparison of methods for quantification of MVOC in indoor environments].

For several years now, MVOC have been regarded as indicators for microbial growth in indoor environments. Until now, a direct correlation between the occurrence of microfungi and MVOC could not be shown in scientific investigations. One reason may be that different analytical methods were applied, and moreover they were not validated sufficiently. The present investigation aimed to test the comparability of both methods (Tenax adsorption/thermal desorption; charcoal adsorption/elution). It turned out that with both methods comparable results can be achieved if the technical handling of the calibration is standardized to a wide extent. Thus, highest demands have to be made on quality assurance. Therefore, it is necessary to formulate technical regulations for the quantification of MVOC.

Air Pollutants, Occupational↗
PubMed2005

Capsule endoscopy in gastrointestinal lymphomas.

BACKGROUND AND STUDY AIMS: Capsule endoscopy (CE) is a new procedure for small-bowel imaging. The potential contribution of this method to the diagnosis and staging of gastrointestinal lymphomas has not yet been evaluated. The aim of this prospective study was to assess the frequency and morphology of different forms of intestinal pathology in patients with gastrointestinal lymphomas. PATIENTS AND METHODS: Commercially available capsule video endoscopes were administered to 27 patients (16 men and 11 women, aged 27-77) with known gastrointestinal lymphomas. CE was also carried out in 30 control individuals. RESULTS: All seven patients with primary intestinal lymphomas who were examined were found to have pathological findings on CE--four with ulcerations, four with nodes, three with villous atrophy, and one with plaques/white villi. One patient with severe diarrhea was examined three times before and after chemotherapy, and improvement of the lesions was evident, as well as resolution of diarrhea. Twenty patients with gastric lymphoma were examined (16 with low-grade and four with high-grade B cell lymphomas). The capsule did not leave the stomach in three patients, suggesting impaired motility. The small-bowel transit times were 261+/-41 min for intestinal lymphoma, 245+/-62 min for gastric lymphoma, and 224+/-82 min for controls (P>0.05). Five of the 20 patients with gastric lymphoma had pathological findings in the intestine--three with plaques/white villi, two with nodes, and two with villous atrophy. In two patients, subsequent biopsies revealed secondary follicular lymphoma and high-grade lymphoma, respectively. CONCLUSIONS: CE is a valuable diagnostic tool for defining the extent of bowel involvement and assessing the efficacy of treatment in patients with gastrointestinal lymphoma.

Adult↗
PubMed2004

Attaching and effacing Escherichia coli isolated from dogs in Brazil: characteristics and serotypic relationship to human enteropathogenic E. coli (EPEC).

Escherichia coli isolates recovered from 182 fecal specimens from dogs up to five months old from the cities of São Paulo and Campinas, SP, Brazil, were examined by polymerase chain reaction (PCR) for several virulence factors and properties. The eae gene was found in 23 isolates of E. coli from 22 dogs, 19 of 146 (13%) from dogs with diarrhea and 3 of 36 (8.3%) from dogs with no diarrhea. Two different eae+ isolates were recovered from one dog with diarrhea. Isolates from two dogs with diarrhea harbored the bfpA gene, and none of the isolates possessed genes for enterotoxins, the EAF plasmid or Shiga toxins. PCR showed that, among the 23 isolates, eight were positive for beta intimin, six for gamma, two for, one for alpha, one for kappa, and five showed no amplification with any of the nine pairs of specific intimin primers used. PCR also showed that the LEE (locus of enterocyte effacement) was inserted in selC in four isolates, likely in pheU in seven isolates, and in undetermined sites in twelve isolates. Fifteen isolates adhered to HEp-2 cells and were fluorescence actin staining (FAS) positive. The predominant adherence pattern was the localized adherence-like (LAL) pattern. The eae-positive isolates belonged to a wide diversity of serotypes, including O111:H25, O119:H2 and O142:H6, which are serotypes that are common among human EPEC. These results confirmed the presence of EPEC in dogs (DEPEC) with and without diarrhea. The virulence factors found in these strains were similar to those in human EPEC, leading to the possibility that EPEC may move back and forth among human and canine populations.

Adhesins, Bacterial↗
PubMed2004

[Palliative treatment for colorectal cancer].

Over 50,000 new cases of colorectal cancer are diagnosed in Germany every year. About half of these patients will be cured by surgery. The other reoccur or present primarily with advanced disease. Recently, the survival of patients with metastasized disease has been prolonged from about 6 months with best supportive care alone to more than 20 months with combination chemotherapy. Therefore, adequate palliation is reasonable. Irresectable liver metastasis can be treated by locally ablative procedures such as radiofrequency ablation (RFA) or laserinduced thermotherapy (LITT). In the individual case resection of lung or brain metastasis should be discussed. Practitioners have to deal with plenty of supportive opportunities e.g. analgesics, bisphosphonates, central acting drugs, nutrition but also with drug side effects. In centers different endoscopic or interventional radiologic procedures are offered. Considering the variety of therapeutic options, it is prudent to discuss individual treatment plans in an interdisciplinary "tumor board" and involve the practitioners in the decision making.

Colorectal Neoplasms↗
PubMed2004

[Pancreatic tail tumor as an unusual first manifestation of Wegener's disease].

A fifty-year-old, previously healthy woman presented with abdominal pain and weight loss. Diagnostic work-up revealed a mass in the tail of the pancreas with the appearance of a pancreatic carcinoma. Partial pancreatectomy was performed. Postoperatively, the patient's kidney function deteriorated. Pathohistological examination of the resected tissue showed a granulomatous vasculitis but no maligant tumor. Renal biopsy revealed a rapid progressive glomerulonephritis. Positive C-ANCA screening confirmed the diagnosis of Wegener's disease and an immunosuppressive therapy was established. This case demonstrates the difficult management of a potentially benign pancreatic mass, as reliable discrimination from pancreatic adenocarcinoma is not always possible.

Abdominal Pain↗
PubMed2004

Pathogen removal efficiency from UASB + BF effluent using conventional and UV post-treatment systems.

The aim of this study was to verify the efficiency of removal of microorganisms in effluents of a Wastewater Treatment Plant (WWTP) comprising an association of a UASB reactor followed by three submerged aerated biofilters (BAF) and one tertiary filter. The WWTP designed to treat domestic wastewater from a population of 1,000 inhabitants showed high removal efficiency for organic matter and suspended solids. Helminth eggs were also efficiently removed from the tertiary effluent and were found in the sludge from the UASB reactor; however, removal of bacteria in this system was very low. To enhance the efficiency of the system, the effluent from tertiary filters was submitted to UV disinfection in a real scale reactor. Our results showed that UV irradiation was very effective at lowering the concentrations of E. coli, thermotolerant coliforms and coliphages to acceptable levels for agricultural reuse. Salmonella spp. and helminth eggs were seeded into the tertiary effluent before passing through the UV reactor. Salmonella was not found in the final effluent, but helminth eggs were not completely inactivated by UV irradiation and viable eggs were detected after 28 d of incubation.

Agriculture↗
PubMed2004

Disinfection of sludge using lime stabilisation and pasteurisation in a small wastewater treatment plant.

Removal efficiency of faecal coliforms and helminth eggs was evaluated in a small wastewater treatment plant (WWTP) serving a population of 1,000. This system was formed by the association in series of a UASB reactor and four submerged aerated biofilters. The density of faecal coliforms and the count of helminth eggs were estimated in the liquid and solid phases of the system. Two different methods of disinfecting sludge were investigated: (a) chemical treatment with lime and (b) a physical treatment by pasteurisation. As expected, the association UASB + BF was very efficient at removal of helminth eggs from the final tertiary effluent, but coliforms were still present at high densities. Lime treatment and pasteurisation of sludge were very effective methods of disinfection and produced a sludge safe for final disposal.

Animals↗
PubMed2003

[Limitations of laparoscopic visceral surgery in oncology].

Controversial discussion focuses on the application of laparoscopic curative resection for cancer due to oncologic radicality,tumor cell dissemination, and port site metastases. Considering the limitations of laparoscopic surgery, it is necessary to objectively evaluate whether laparoscopic surgery is associated with an improved quality of curative treatment. Therefore, controlled studies comparing the results of laparoscopic vs conventional cancer surgery are mandatory. To date, comparable findings on short-term outcome of laparoscopy with open resection can only be shown for colorectal cancer. However, long-term data including recurrence and survival are still missing as randomized studies (phase IIIb) are still to be completed. Consequently, laparoscopic curative resection should only be performed within controlled trials. In terms of the upper GI tract, minimally invasive surgery has proven to be technically feasible in expert centers including limited resections for early gastric cancer, left pancreatectomies, or hepatic resections for malignancy. Finally, laparoscopy has gained acceptance in the field of diagnosis (e.g., staging laparoscopy, laparoscopic ultrasound) and palliative treatment (e.g. gastroenterostomy, thermoablation) without the need for controlled studies.

Colorectal Neoplasms↗
PubMed2003

[Surgical therapy of rectal carcinoma].

Total mesorectal excision (TME) has gained a revolutionary impact on the surgical therapy of rectal cancer within the last 2 decades, providing superior local tumor control in comparison to conventional resection. Consequently, 85% of rectal carcinomas can be resected by sphincter-preserving surgery without compromising either oncologic radicality or continence. With the introduction of TME, local recurrence rates have been reliably decreased below 10% after curative resection. Surgical dissection along the connective tissue space between rectal and parietal pelvic fascia with complete mesorectal excision results in reliable excision of all relevant lymphatic pathways with preservation of continence and sexual function. Complete removal of a TME specimen is mandatory in carcinomas of the middle and lower third of the rectum. Both removal of the complete TME specimen and careful pathologic examination of the circumferential resection margin have decisive significance. An additional pelvic lymphadenectomy with the potential risk of increased morbidity does not improve prognosis. As a spread of tumor distally along the bowel wall rarely exceeds a few centimeters, a distal resection margin of 1-2 cm is oncologically sufficient in sphincter-saving procedures without compromising prognosis. Taken together, the convincing results of TME provide a rationale for using TME as the dissection policy of choice to resect rectal cancers in the distal two-thirds of the rectum, despite the absence of direct evidence from prospective randomized trials. The question whether laparoscopic curative resection for rectal cancer is oncologically adequate cannot be definitely answered to date, as results of randomized studies are currently missing. However, the preliminary results of laparoscopic resection for rectal cancer provided by centers are promising.

Anal Canal↗
PubMed2003

Cytology and image cytometry after colonic lavage: a complementary diagnostic tool in patients with ulcerative colitis.

BACKGROUND: Patients with extensive, long-standing ulcerative colitis have increased risk of colorectal cancer. AIMS: To improve the detection of high-risk patients, using a combination of colonic cytology, histology, and DNA image cytometry after segmental colonic lavage. PATIENTS: A series of 16 patients (8 high-risk patients) with ulcerative colitis were investigated. METHODS: After segmental lavage step, biopsies were obtained. Gradient centrifugation of the colonic fluid was performed for isolation and purification of epithelial cells. The smears and biopsy specimens obtained were stained for routine interpretation and for DNA image cytometry. RESULTS: Segmental lavage could be performed in all patients. Specimens from two high-risk patients showed low grade dysplasia and atypia by means of histology and cytology, respectively. In one patient, without increased colorectal cancer risk, atypia was detected. Three patients in the high-risk group, two of those diagnosed as positive for dysplasia and atypia, showed aneuploidy histologically and cytologically. DNA aneuploidy, in cytological material, was found exclusively in three low-risk patients, one of those had atypia cytologically. CONCLUSIONS: Isolation and purification of epithelial cells after segmental colonic lavage using density gradient centrifugation can be performed as part of routine endoscopy. It provides information about atypical cells and DNA aneuploidy as additional markers of malignant transformation. The combination of cytologic examination and DNA image cytometry might improve the detection of high-risk ulcerative colitis patients.

Adult↗
PubMed2003

Personality traits, depression and migraine in women: a longitudinal study.

Our purpose was to examine the association between personality traits, depression and migraine in the long term. In 56 women with migraine a psychological assessment was carried out to assess the presence of major depression, and the Minnesota Multiphasic Personality Inventory (MMPI) and the State and Trait Anxiety Inventory (STAI) were administered at baseline (T0) and after 6-7 years (T2). Frequency, severity and duration of migraine were recorded at T0, after treatment (T1) and at T2, and their relation to the prevalence of depression and to the MMPI and STAI data was examined (ANOVA, Student's t-test, chi2 analysis, and multiple regression analysis). Pain parameters improved in all patients in T0-T1, but at T2 were higher in patients with depression at T0. The patients whose migraine improved at T2 had, at T0 and T2, significantly lower MMPI and STAI scores. Multiple regression analysis showed a correlation of the MMPI depression score and STAI 1,2 scores at T0 with headache frequency at T2. We conclude that the co-occurrence of migraine, personality changes and depression in women does not appear to influence the results of treatment at short-term, but it seems to be influential on headache history in the long term.

Adult↗
PubMed2003

A randomized, blinded, prospective trial to compare the safety and efficacy of three bowel-cleansing solutions for colonoscopy (HSG-01*).

BACKGROUND AND STUDY AIMS: There are conflicting data regarding the optimal bowel preparation for colonoscopy. This study was carried out to compare the efficacy, safety, and tolerability of three widely used bowel lavage solutions: the standard polyethylene glycol-electrolyte solution based on the GoLytely formulation (PEG-EL1; Klean-Prep); a sulphate-free PEG-EL solution based on the NuLytely formulation (PEG-EL2, Endofalk); and a sodium phosphate preparation (NaP, Fleet Phospho-Soda). PATIENT AND METHODS: A total of 185 consecutive patients scheduled for elective colonoscopy were prospectively randomly assigned to undergo pre-colonoscopic bowel cleansing with either 4 l of PEG-EL1 (n=64), 3 l of PEG-EL2 (n=59), or 90 ml of NaP (n=62). The quality of preparatory colonic cleansing for each segment from the rectum to the ascending colon was scored on a five-level rating scale (1, very good to 5, very poor) by endoscopists who were blinded with regard to the type of preparation used. The primary outcome measure for the comparison of treatments was the "worst" score in any of the rated bowel segments. Safety and tolerability were evaluated by means of a symptom questionnaire completed by each patient immediately before the procedure. RESULTS: Of the 185 patients who were randomly assigned to one of the three treatments, 175 underwent colonoscopy and 173 were evaluable with regard to efficacy - 59, 54, and 60 patients treated with PEG-EL1, PEG-EL2, and NaP, respectively. The treatment groups were comparable with regard to the baseline characteristics. PEG-EL1 was statistically significantly superior to the other treatments in relation to the "worst cleansing" score ( P</=0.003). In addition, colonoscopic visualization was markedly better in each of the five bowel segments and general "very good" or "good" ratings were achieved in more than 90 % of patients treated with PEG-EL1. The percentages were consistently lower in the other two groups, particularly in the ascending colon. With the exception of the sigmoid, the differences in all segments of the large bowel were statistically significant (P</=0.04). Patient satisfaction was comparable between the treatment groups. Adverse events (mainly nausea/vomiting and abdominal pain) and deviations in laboratory values occurred more frequently in the NaP group. CONCLUSIONS: Preparatory PEG-EL1 (Klean-Prep) was significantly superior to PEG-EL2 (Endofalk) and NaP (Fleet Phospho-Soda) in achieving effective cleansing of the entire colon prior to colonoscopy. On the basis of these data, PEG-EL1 can be regarded as the "gold standard" for bowel cleansing prior to colonoscopy.

Adolescent↗
PubMed2003

Better acceptance of Fecal Occult Blood Test (FOBT) for colorectal cancer screening during hospitalization.

INTRODUCTION: Colorectal cancer (CRC) is a leading cause of illness and death in the Western world. Screening with fecal occult blood test (FOBT) significantly reduces the death rate and the incidence from CRC but these tests are not widely accepted. We investigated the possible contribution of hospitalization to a better acceptance of CRC screening. PATIENTS AND METHODS: From October 1998 through September 2000, 721 consecutive patients between 45 and 75 years of age admitted for various reasons were asked for participation in the study. They were asked to participate in FOBT-screening. In case of refusal of FOBT they were asked a second time after detailed information. In patients who accepted 3 consecutive FOBT's were performed. In case of positive FOBT results colonoscopy and gastroscopy were performed. RESULTS: 149 (82 male/67 female) patients were included. 94 (63.5%) of them agreed to undergo FOBT primarily and 10 (6.8%) secondarily after detailed information. The total acceptance rate of the FOBT was 69.8% (m/w : 69.1%/71.6%). In one of 5 cases with a positive FOBT result colorectal cancer (CRC) was diagnosed. Information on repetition of FOBT after one year could be obtained from 82 patients (55%). 37 patients (45%) had undergone repeated FOBT. None of the 37 patients was motivated by the FOBT screening during hospitalization. CONCLUSIONS: Staying in a hospital offers a good chance to achieve a higher acceptance of the FOBT. Therefore, hospitalization may contribute to a better colorectal cancer prevention. However, motivation to regularly repeat screening does not last in all patients. Therefore, public campaigns as well as medical counseling need to continuously stress the necessity of CRC screening procedures.

Aged↗
PubMed2003

[Laparoscopic therapy of colorectal cancer--wishful thinking or realism?].

The laparoscopic resection of the colon and rectum is established for surgery of benign diseases. The main advantages compared to the open-conventional operation technique are reduced postoperative pain, reduced negative influences on pulmonary and gastrointestinal functions as well as a shorter reconvalescence. Minimally invasive curative resections of colorectal carcinomas are still controversially discussed concerning sufficient radicality and the spread of tumor cells. The given oncological standards of the conventional approach can be kept without restriction when resections of the colon and rectum are performed laparoscopically. Newer comparative studies do not describe raised recurrence or lower survival rates following the minimal-invasive procedure. In the coming years prospective randomized multicenter studies must give proof whether or not the long-term survival is comparable with the conventional approach.

Aged↗