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Biomedical subjects

A Wenger

Publications and source records attributed to A Wenger.

At least 19 recordsLinked to original sources

[The influence of geometric visual illusions on saccadic eye movements].

BACKGROUND: The aim of this study was to investigate whether visually perceived length differences of Mueller-Lyer figures result in amplitude differences of saccadic eye movements along the figures. METHODS: Video recordings of eye movements were obtained from 35 healthy volunteers (aged 18 - 30 years) when scanning the endpoints of Mueller-Lyer targets. RESULTS: Saccades between the ends of lines with inward-pointing arrowheads had significantly greater amplitudes than saccades between the ends of lines with outward-pointing arrowheads. This bias was observed for both horizontal and vertical target orientations, and was maintained with a smaller amplitude, after fixation periods were extended from 1 s to 4 s. CONCLUSIONS: Changes in length perception by visual illusions correspond with changes in the amplitude of saccadic eye movements. Therefore, recordings of saccadic eye movements offer the opportunity to assess changes in visual object perception based on changes of central image processing at the cortical level.

Adolescent↗

Faucets as a reservoir of endemic Pseudomonas aeruginosa colonization/infections in intensive care units.

OBJECTIVE: To evaluate the role of faucets as a reservoir for Pseudomonas aeruginosa colonization/infection of patients hospitalized in intensive care units (ICUs). DESIGN: Prospective epidemiological investigation performed during a nonepidemic period of 1 year. The inner part of the ICU faucets were swabbed for P. aeruginosa. Data were recorded on all patients with at least one culture of a clinical specimens positive for P. aeruginosa. Pulsed-field gel electrophoresis was used to characterize the strains. SETTING: Five ICUs of a university hospital which are supplied by two separate water distribution networks. PATIENTS: During a 1-year period 132 cases were investigated. RESULTS: In 42% of cases (56/132) there were isolates identical to those found in the faucets, with a total of nine different genotypes. Among the nine genotypes isolated from both patients and faucets one of them, the most prevalent, was isolated in the two networks and in 30 cases. The other eight genotypes were recovered almost exclusively from either one (three genotypes in 12 cases) or the other (five genotypes in 12 cases) network and from the patients in the corresponding ICUs. CONCLUSIONS: These results suggest that the water system of the ICUs was the primary reservoir of patient's colonization/infection with P. aeruginosa in a substantial proportion of patients, although the exact mode of acquisition could not be determined.

Colony Count, Microbial↗

Nosocomial nontyphoidal salmonellosis after antineoplastic chemotherapy: reactivation of asymptomatic colonization?

An increased frequency of nontyphoidal salmonellosis is well established in cancer patients, but it is unclear whether this represents increased susceptibility to exogenous infection or opportunistic, endogenous reactivation of asymptomatic carriage. In a retrospective study, a simple case definition was used to identify the probable presence of reactivation salmonellosis in five cancer patients between 1996 and 2002. Reactivation salmonellosis was defined as the development of nosocomial diarrhea >72 h after admission and following the administration of antineoplastic chemotherapy in an HIV-seronegative cancer patient who was asymptomatic on admission, in the absence of epidemiological evidence of a nosocomial outbreak. Primary salmonellosis associated with unrecognized nosocomial transmission or community acquisition and an unusually prolonged incubation period could not entirely be ruled out. During the same time period, another opportunistic infection, Pneumocystis pneumonia, was diagnosed in six cancer patients. Presumably, asymptomatic intestinal Salmonella colonization was converted to invasive infection by chemotherapy-associated intestinal mucosal damage and altered innate immune mechanisms. According to published guidelines, stool specimens from patients hospitalized for longer than 72 h should be rejected unless the patient is neutropenic or >or=65 years old with significant comorbidity. However, in this study neutropenia was present in only one patient, and four patients were <65 years old. Guidelines should thus be revised in order not to reject stool culture specimens from such patients. In cancer patients, nosocomial salmonellosis can occur as a chemotherapy-triggered opportunistic reactivation infection that may be similar in frequency to Pneumocystis pneumonia.

Adult↗

The nutrition of the chinchilla as a companion animal--basic data, influences and dependences.

This contribution is meant to obtain basic data for feeding chinchillas (ingestion behaviour, feed and water intake) kept as companion animals. The chinchillas ingested more than 70% of their total feed intake during the dark phase (highest level of activity between 9:00 pm and 7:00 am). Daily amounts of feed intake varied between 2.5 (fresh grass) or 2.6 (hay) and 5.5 (pelleted complete diet) g of dry matter per 100 g of body weight. An offered mixed feed based on native components led to a selection of individual ingredients (high palatability: carob, beet pulp, sunflower seeds). The chinchillas' daily water intake varied between 30 (mixed feed in briquette form) and 40 ml (alfalfa cubes) and amounted on average between 1.5 and 3 ml/g of dry matter. Compared with rabbits or guinea-pigs, the chinchillas generally showed noticeable differences (rhythm of feed intake, palatability of individual ingredients, capacity for digestion, etc.) which must be considered in order to optimize the nutrition of this species.

Animal Feed↗

Evaluation of a novel medium for screening specimens from hospitalized patients to detect methicillin-resistant Staphylococcus aureus.

A novel medium, Oxacillin Resistant Screening Agar (ORSA) medium, was evaluated for the screening of specimens for methicillin-resistant Staphylococcus aureus (MRSA) in the hospital setting. Screening swabs (swabs of the nose, throat, perineum, and infected sites) were inoculated onto the new ORSA medium and into an enrichment broth (Muller-Hinton broth supplemented with NaCl and oxacillin). After 24 h of incubation, the enrichment broth was subcultured onto one ORSA plate and one lipovitellin Chapman salt agar plate. The sensitivities for the detection of MRSA were calculated for each medium alone and for the media in combination. A low sensitivity (74%) was obtained when ORSA medium was used alone as a primary culture, whereas the sensitivity was 88% when a single selective enrichment broth was used. Among the 414 blue colonies observed on ORSA plates, only 47% were found to be MRSA, 40% were coagulase-negative staphylococci, 7% were Enterococcus species, and 2% were methicillin-sensitive S. aureus. The optimal incubation time for the ORSA plates was evaluated. On primary culture, 38% of the blue MRSA colonies were visible only after 48 h of incubation (no blue colonies were not seen after 24 h of incubation), whereas 94% of the colonies were already visible at 24 h when ORSA plates were used for subcultures. In conclusion, the advantage of the novel ORSA medium is the ease of recognition of mannitol-fermenting bacteria, but further identification tests are needed to confirm the identification of S. aureus. An enrichment broth is still needed to ensure a good sensitivity for the recovery of MRSA, and an incubation time of 48 h is required for primary culture on ORSA medium.

Clinical Laboratory Techniques↗

Plasmid gene delivery to human keratinocytes through a fibrin-mediated transfection system.

We have developed a matrix-mediated transfection system to deliver plasmids to human keratinocytes. The matrix is a soluble, self-hardening fibrin matrix (Tissucol), Baxter) that has been used clinically. Recently it has been shown that full thickness burn wounds can be successfully treated with a keratinocyte fibrin glue suspension. Further, it has been demonstrated that hEGF transfected cells accelerate wound healing. In this study, we inoculated the matrix with the hEGF expression plasmid and resuspended the matrix with either cultured or noncultured human keratinocytes. We obtained successful transfection rates of these cells (up to a 100-fold increase compared to controls containing no EGF expression plasmid) in vitro. After transplantation to full thickness wounds on athymic mice we were able to show a 180-fold increase in EGF concentration compared to controls, which persisted over the entire 7-day monitored period, decreasing from 180 to 20 pg/mL at day seven. This unique approach indicates the possible utility to combine a matrix for cell transplantation with a transfection system to release therapeutic proteins in vitro and in vivo.

Animals↗

Community-acquired pneumonia. A prospective outpatient study.

We initiated a prospective study with a group of practitioners to assess the etiology, clinical presentation, and outcome of community-acquired pneumonia in patients diagnosed in the outpatient setting. All patients with signs and symptoms suggestive of pneumonia and an infiltrate on chest X-ray underwent an extensive standard workup and were followed over 4 weeks. Over a 4-year period, 184 patients were eligible, of whom 170 (age range, 15-96 yr; median, 43 yr) were included and analyzed. In 78 (46%), no etiologic agent could be demonstrated. In the remaining 92 patients, 107 etiologic agents were implicated: 43 were due to "pyogenic" bacteria (39 Streptococcus pneumoniae, 3 Haemophilus spp., 1 Streptococcus spp.), 39 were due to "atypical" bacteria (24 Mycoplasma pneumoniae, 9 Chlamydia pneumoniae, 4 Coxiella burnetii, 2 Legionella spp.), and 25 were due to viruses (20 influenza viruses and 5 other respiratory viruses). There were only a few statistically significant clinical differences between the different etiologic categories (higher age and comorbidities in viral or in episodes of undetermined etiology, higher neutrophil counts in "pyogenic" episodes, more frequent bilateral and interstitial infiltrates in viral episodes). There were 2 deaths, both in patients with advanced age (83 and 86 years old), and several comorbidities. Only 14 patients (8.2%) required hospitalization. In 6 patients (3.4%), the pneumonia episode uncovered a local neoplasia. This study shows that most cases of community-acquired pneumonia have a favorable outcome and can be successfully managed in an outpatient setting. Moreover, in the absence of rapid and reliable clinical or laboratory tests to establish a definite etiologic diagnosis at presentation, the spectrum of the etiologic agents suggest that initial antibiotic therapy should cover both S. pneumoniae and atypical bacteria, as well as possible influenza viruses during the epidemic season.

Adolescent↗

The effects of a pediatric unilateral inguinal hernia clinical pathway on quality and cost.

BACKGROUND/PURPOSE: The purpose of this study is to discover whether a pediatric inguinal hernia surgical clinical pathway (CP) reduces the frequency of wound infections, return visits, times associated with surgical repair, or costs. METHODS: A multidisciplinary team developed the inguinal hernia surgical clinical pathway. Healthy children greater than 50 weeks gestational age who required unilateral hernia repair were considered for the study. Two groups were formed: (1) an intervention group selected randomly (n = 46, CI = 95%, power = .80) from patients enrolled from November 1996 through April 1997, and (2) a retrospective cohort control group (n = 46) matched to each intervention patient by age, gender, and medical history. Analysis of variance and chi2 testing were used to test for significant differences between the 2 groups in postoperative wound infections, readmission and emergency department return visits within 72 hours, times associated with surgical repair, and costs. RESULTS: There were no significant differences in postoperative wound infections, times associated with surgical repair, or readmission rates within 72 hours. Total cost significantly decreased, by 10% (P< or = .05), for pathway patients ($982 v $880). CONCLUSION: These results show that the use of a pediatric inguinal hernia surgical clinical pathway is associated with reduced cost while maintaining quality of care.

Child, Preschool↗

[Pneumococcal antibiotic resistance].

In 1875, 7 years prior to the description of the Koch bacillus, Klebs visualized the first Streptococcus pneumoniae in a pleural fluid. Since then, this organism has played a determinant role in biomedical science. From a biological point of view, it was largely implicated in the development of passive and active immunization by serotherapy and vaccination, respectively. Genetic transformation was also first observed in S. pneumoniae, leading to the discovery of DNA. From a clinical point of view, S. pneumoniae is still today a prime cause of otitis media in children and of pneumonia in all age groups, as well as a predominant cause of meningitis and bacteremia. In adults, bacteremia is still entailed with a mortality of over 25%. Although S. pneumoniae remained very sensitive to penicillin for many years, penicillin-resistance has emerged and increased dramatically over the last 15 years. During this period of time, the frequency of penicillin-resistant isolates has increased from < or = 1% to frequencies varying from 20 to 60% in geographic areas as diverse as South Africa, Spain, France, Hungary, Iceland, Alaska, and numerous regions of the United States and South America. In Switzerland, the current frequency of penicillin-resistant pneumococci ranges between 5 and > or = 10%. The increase in penicillin-resistant pneumococci correlates with the intensive use of beta-lactam antibiotics. The mechanism of resistance is not due to bacterial production of penicillinase, but to an alteration of the bacterial target of penicillin, the so-called penicillin-binding proteins. Resistance is subdivided into (i) inter mediate level resistance (minimal inhibitory concentration [MIC] of penicillin of 0.1-1 mg/L) and (ii) high level resistance (MCI > or = 2 mg/L). The clinical significance of intermediate resistance remains poorly defined. On the other hand, highly resistant strains were responsible for numerous therapeutical failures, especially in cases of meningitis. Antibiotics recommended against penicillin-resistant pneumococci include cefotaxime, ceftriaxone, imipenem and in some instances vancomycin. However, penicillin-resistant pneumococci tend to present cross-resistances to all the antibotics of the beta-lactam family and could even become resistant to the last resort drugs mentioned above. Thus, in conclusion, the explosion of resistance to penicillin in pneumococci is a ubiquitous phenomenon which must be fought against by (i) a strict utilization of antibiotics, (ii) the practice of microbiological sampling of infected foci before treatment, (iii) the systematic surveillance of resistance profiles of pneumococci against antibiotics and (iv) the adequate vaccination of populations at risk.

Adult↗

Unusual spread of a penicillin-susceptible methicillin-resistant Staphylococcus aureus clone in a geographic area of low incidence.

We describe the unusual spread of a penicillin-susceptible methicillin-resistant Staphylococcus aureus (MRSA) clone in hospitals in western Switzerland, where the incidence of MRSA is usually low. During a 2-year period, this clone had been responsible for several outbreaks and had been isolated from >156 persons in 21 institutions. Molecular typing by pulsed-field gel electrophoresis (PFGE) demonstrated that all of these isolates belonged to the same clone. In 1 of the outbreaks, involving 30 cases, the clone was responsible for at least 17 secondary cases. In contrast, during the period of the latter outbreak, 9 other patients harboring different MRSA strains, as assessed by PFGE, were hospitalized in the same wards, but no secondary cases occurred. These observations suggest that this clone, compared with other MRSA strains, had some intrinsic factor(s) that contributed to its ability to disseminate and could thus be considered epidemic.

Anti-Bacterial Agents↗

Evaluation of MRSA-Screen, a simple anti-PBP 2a slide latex agglutination kit, for rapid detection of methicillin resistance in Staphylococcus aureus.

The MRSA-Screen test (Denka Seiken Co., Ltd., Tokyo, Japan), consisting of a slide latex agglutination kit that detects PBP 2a with a monoclonal antibody, was blindly compared to the oxacillin disk diffusion test, the oxacillin-salt agar screen, and PCR of the mecA gene for the detection of methicillin resistance in Staphylococcus aureus. A total of 120 methicillin-susceptible S. aureus (MSSA) and 80 methicillin-resistant S. aureus (MRSA) isolates, defined by the absence or presence of the mecA gene, respectively, were tested. The MRSA-Screen test, the oxacillin disk diffusion test, and the oxacillin-salt agar screening test showed sensitivities of 100, 61.3, and 82.5% and specificities of 99.2, 96.7, and 98.3%, respectively. We conclude that the MRSA-Screen is a very accurate, reliable, and fast test (15 min) for differentiation of MRSA from MSSA colonies on agar plates.

Antibodies, Monoclonal↗

[Chronic pelvic pain--a still too little appreciated disease picture].

Chronic pelvic pain often means for patients as well as for their physicians a dilemma concerning diagnosis and therapy: the common medical approach does often not fit for essential therapeutic needs, which should include somatic examination as well as psychosomatic (psychotherapeutic) concepts for escaping from further somatic chronification typical for CPP-patients. The study performed during 1995-98 with 220 patients of the Department of Obstetrics & Gynecology in collaboration with the Psychosomatic Department in the St. Johann's Hospital of Salzburg has shown results about laparoscopic/pelviscopic and psychosomatic interventions in patients with chronic pelvic pain. Evidence-based somatic medicine is not able to explain the discrepancy between pathomorphology and intensity of pain in CPP-patients. The specific dilemma in treating CPP-patients could be characterized as the following: Somatisation is often the one and only symptom presented by CPP-patients to gynecologists. It is the physician's task to stay in a relationship with the patient and treat her symptomatically on somatic symptoms. The relationship will provide the chance to introduce a psychosomatic approach and engage psychotherapeutic work on the reluctance of accepting a psychogenesis of CPP. Gynecologists lack psychosomatic knowledge and concepts for treatment and therefore often contribute to the chronification of CPP in patients approached only in somatic terms.

Chronic Disease↗

Are trustworthiness and fairness enough? Contextual family therapy and the good family.

The moral dimension of family therapy theory and practice has received increasing attention in recent years. Boszormenyi-Nagy was among the first to see that family therapy and moral questions are inseparable. His focus on relational ethics has helped us to reappropriate individual responsibility and accountability within a systemic context. Although contextual therapy has clearly enriched the field, we argue that its emphasis on trustworthiness and fairness provides a limited view of the good in family life and leads to three related problems. First, Boszormenyi-Nagy offers a compelling ethical vision of the family and then denies that he has done so, which undermines some of his key moral claims. Second, because fairness is defined subjectively, contextual therapy may not have the resources to deal with legitimate differences in family ideals. Third, the reliance on self-interest as the primary motive for trustworthy relating appears to be self-defeating. We offer a hermeneutic perspective that takes a broader approach to the good. It places greater emphasis on the social and historical context, deals squarely with different understandings of the good in family life, and recommends an approach to resolving these differences.

Ethics↗

[Antibiotic resistance in pneumococci].

In 1875, 7 years prior to the description of the Koch bacillus, Klebs visualized the first Streptococcus pneumoniae in pleural fluid. Since then, this organism has played a decisive role in biomedical science. From a biological point of view, it was extensively involved in the development of passive and active immunization by serotherapy and vaccination respectively. Genetic transformation was also first observed in S. pneumoniae, leading to the discovery of DNA. From a clinical point of view, S. pneumoniae is today still a prime cause of otitis media in children and of pneumonia in all age groups, as well as a predominant cause of meningitis and bacteremia. In adults, bacteremia still has a mortality of over 25%. Although S. pneumoniae remained very sensitive to penicillin for many years, penicillin-resistant strains have emerged and increased dramatically over the last 15 years. During this period the frequency of penicillin-resistant isolates has increased from < or = 1% to frequencies varying from 20 to 60% in geographic areas as diverse as South Africa, Spain, France, Hungary, Iceland, Alaska, and numerous regions of the United States and South America. In Switzerland, the current frequency of penicillin-resistant pneumococci ranges between 5 and > or = 10%. The increase in penicillin-resistant pneumococci correlates with the intensive use of beta-lactam antibiotics. The mechanism of resistance is not due to bacterial production of penicillinase but to an alteration of the bacterial target of penicillin, the so-called penicillin-binding proteins. Resistance is subdivided into (1) intermediate level resistance (minimal inhibitory concentration [MIC] of penicillin of 0.1-1 mg/l) and (2) high level resistance (MCI > or = 2 mg/l). The clinical significance of intermediate resistance remains poorly defined. On the other hand, highly resistant strains have been responsible for numerous therapeutic failures, especially in cases of meningitis. Antibiotics recommended against penicillin-resistant pneumococci include cefotaxime, ceftriaxone, imipenem and in some instances vancomycin. However, penicillin-resistant pneumococci tend to present cross-resistances to all the antibiotics of the beta-lactam family and could even become resistant to the last resort drugs mentioned above. Thus, the explosion of resistance to penicillin in pneumococci is a ubiquitous phenomenon which must be fought against by (1) avoiding excessive use of antibiotics, (2) the practice of microbiological sampling of infected foci before treatment, (3) the systematic surveillance of resistance profiles of pneumococci against antibiotics and (4) adequate vaccination of populations at risk.

Anti-Bacterial Agents↗

Quantitative antibiogram as a typing method for the prospective epidemiological surveillance and control of MRSA: comparison with molecular typing.

OBJECTIVE: Evaluation of the quantitative antibiogram as an epidemiological tool for the prospective typing of methicillin-resistant Staphylococcus aureus (MRSA), and comparison with ribotyping. METHODS: The method is based on the multivariate analysis of inhibition zone diameters of antibiotics in disk diffusion tests. Five antibiotics were used (erythromycin, clindamycin, cotrimoxazole, gentamicin, and ciprofloxacin). Ribotyping was performed using seven restriction enzymes (EcoRV, HindIII, KpnI, PstI, EcoRI, SfuI, and BamHI). SETTING: 1,000-bed tertiary university medical center. RESULTS: During a 1-year period, 31 patients were found to be infected or colonized with MRSA. Cluster analysis of antibiogram data showed nine distinct antibiotypes. Four antibiotypes were isolated from multiple patients (2, 4, 7, and 13, respectively). Five additional antibiotypes were isolated from the remaining five patients. When analyzed with respect to the epidemiological data, the method was found to be equivalent to ribotyping. Among 206 staff members who were screened, six were carriers of MRSA. Both typing methods identified concordant of MRSA types in staff members and in the patients under their care. CONCLUSIONS: The quantitative antibiogram was found to be equivalent to ribotyping as an epidemiological tool for typing of MRSA in our setting. Thus, this simple, rapid, and readily available method appears to be suitable for the prospective surveillance and control of MRSA for hospitals that do not have molecular typing facilities and in which MRSA isolates are not uniformly resistant or susceptible to the antibiotics tested.

Bacterial Typing Techniques↗

Molecular epidemiology of methicillin-resistant Staphylococcus aureus at a low-incidence hospital over a 4-year period.

OBJECTIVE: To study the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) over a prolonged period of time with the aid of a molecular typing method (ribotyping). SETTING: A 1,000-bed tertiary university medical center. PATIENTS AND METHODS: Defined epidemiological data were recorded for all patients culture-positive for MRSA between 1989 and 1992. Ribotyping of MRSA strains was performed using three restriction enzymes: EcoRV, HindIII, and KpnI. RESULTS: From 1989 to 1992, MRSA was isolated from clinical specimens in 98 patients and from surveillance cultures in 27 patients. Among the 122 isolates available for typing, 26 different ribotypes were identified. In 20% of the cases, MRSA was community-acquired, and a third of these patients never had been hospitalized previously. Nine ribotypes were responsible for more than one case (2 to 64 patients); 17 appeared only once. Epidemiological data correlated with ribotyping results revealed 14 epidemiologic clusters involving six different ribotypes, whereas only three outbreaks were suspected initially. The median follow-up after the last isolation of a given ribotype was 14 months (range, 1 to 42) for clusters and 25 months (range, 1 to 46) for ribotypes that appeared only once. During clusters, only 16% of the cases occurred after the implementation of control measures in the ward (breakthrough cases). CONCLUSIONS: The high diversity of MRSA strains observed over 4 years suggested that new strains were introduced continuously in our hospital. Furthermore, that 17 ribotypes were isolated only once, that breakthrough cases represented only 16% of the cases in clusters, and that the follow-up duration after the last isolation of a given ribotype was more than 14 months suggest that infection control measures were effective in limiting the nosocomial spread of MRSA over a prolonged period of time.

Bacterial Typing Techniques↗

Quantitative antibiogram typing using inhibition zone diameters compared with ribotyping for epidemiological typing of methicillin-resistant Staphylococcus aureus.

Antibiogram typing of methicillin-resistant Staphylococcus aureus with selected antibiotics was evaluated as a primary epidemiological typing tool and compared with ribotyping. Antibiograms were derived with the Kirby-Bauer disk diffusion method by using erythromycin, clindamycin, cotrimoxazole, gentamicin, and ciprofloxacin. For typing, antibiogram data were analyzed by similarity analysis of disk zone diameters (quantitative antibiogram typing). One hundred seventy-two isolates were typed. Reproducibility reached 98% for the quantitative antibiogram and 100% for ribotyping. With three selected restriction enzymes (EcoRV, HindIII, and KpnI), 40 epidemiologically unrelated isolates could be classified into 21 ribotypes, whereas quantitative antibiogram typing classified these isolates into 19 groups. To evaluate the discriminatory power of the methods, we calculated an index of discrimination from data obtained with these 40 isolates. This index takes into consideration both the number of types defined by the typing method and their relative frequencies. With both ribotyping and quantitative antibiogram typing, high discrimination indices (0.972 and 0.954, respectively) were obtained. When epidemiological links between patients (ward, period of hospitalization, and contacts between staff and patients) were compared with the results of ribotyping or the quantitative antibiogram typing method, it appeared that both methods were able to discriminate epidemiological clusters, with only a few discrepancies. In conclusion, quantitative antibiogram typing, although not necessarily based on genomic markers, is a simple method which enables a reliable workup of methicillin-resistant S. aureus epidemic when sophisticated molecular typing methods are not available.

Anti-Bacterial Agents↗