[Preventing misuse of antibiotics].
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Anti-Bacterial Agents↗
Biomedical subjects
R Weber
Publications and source records attributed to R Weber.
Relevance of zinc in human sperm flagella and its relation to motility.
OBJECTIVE: To measure the zinc content of human sperm flagella and to analyze its relation to sperm motility. DESIGN: Prospective study. SETTING: Center of Dermatology and Andrology. PATIENT(S): Semen samples collected from 90 andrology patients and healthy donors after 3-5 days of sexual abstinence. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Sperm morphology after Shorr staining, sperm motility, and patient age were recorded. In addition, zinc concentrations in the seminal plasma, sperm heads, and flagella were determined with the use of atomic absorption spectrometry. RESULT(S): The mean zinc concentration was 144.3 mg/L in the seminal plasma and 146.9 mg/L in the whole ejaculate and was significantly correlated with parameters of motility. The sperm heads contained only 6.7% of the zinc that was present in the whole spermatozoon. The zinc concentration in the flagella was negatively correlated with sperm motility and velocity. In addition, it was positively correlated with the percentage of abnormally blue-stained flagella and the age of the patients. CONCLUSION(S): Our results clearly demonstrate the importance of zinc elimination during epididymal sperm maturation for functional competence of the outer dense fibers and, therefore, generation of motility.
Adult↗
Genetic and phenotypic intraspecific variation in the microsporidian Encephalitozoon hellem.
Encephalitozoon hellem is a microsporidian species that causes disseminated infections in HIV-positive patients. Identical genotypes of E. hellem, as assessed by the sequence of the rDNA internal transcribed spacer, have been identified in isolates from humans and from a psittacine bird. However, by analysing the rDNA ITS of four E. hellem isolates from Switzerland (three) and Tanzania (one), two new genotypes were identified. Differences among the E. hellem isolates were also detected by Western blot analysis, but there was no absolute match between ITS genotype and antigen profile. Hence, strain variation exists in E. hellem and the ITS sequence seems a valuable marker in obtaining further insight into the epidemiology of this pathogen.
Acquired Immunodeficiency Syndrome↗
Mechanism of the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans from chlorophenols in gas phase reactions
The pyrolysis of chlorinated phenates at a temperature of about 280 degrees C results in the formation of definite chlorinated dibenzodioxin (PCDD) congeners [1-3]. It is shown that in gas phase reactions chlorophenols react in the presence of oxygen above 340 degrees C not only to PCDD but also to chlorinated dibenzofurans (PCDF). The mechanism of this reaction of chlorophenols to PCDD and PCDF was elucidated. In a first step phenoxyradicals are formed which are capable of forming PCDDs and PCDFs. This is confirmed by the oxygen dependency of the reaction. In an argon atmosphere no dimerization of chlorophenols could be observed at 420 degrees C. By the identification of intermediates and by analyzing the PCDF isomers formed from individual chlorophenols the reaction pathway is elucidated. As intermediates in the formation of PCDFs polychlorinated dihydroxybiphenyls (DOHB) were identified. These are most likely formed by the dimerization of two phenoxy radicals at the hydrogen substituted carbons in ortho-positions under simultaneous movement of the hydrogen atoms to the phenolic oxygen PCDDs are formed in the gas phase via ortho-phenoxyphenols (POP) analogous to the pyrolysis of phenates, but due to the radical mechanism in the first condensation step to POPs not only a chlorine atom is capable for substitution but also the hydrogen atoms. The formation of the DOHBs and their condensation to PCDFs and hydroxylated PCDFs as well as the ratio of PCDD to PCDF formed show a strong dependency on the reaction temperature, the substitution pattern of the chlorophenols and the oxygen concentration.
Journal Article↗
Molecular karyotype diversity in the microsporidian Encephalitozoon cuniculi.
The microsporidian Encephalitozoon cuniculi can infect numerous mammals, including man. Three strains of E. cuniculi have been identified so far, the major marker being the number of a tetranucleotide repeats in the rDNA internal transcribed spacer. We investigated diversity at the chromosomal level through the electrophoretic karyotypes obtained from 15 E. cuniculi isolates from 5 different host species. All preparations provided patterns with 9-12 bands within a narrow molecular size range. Six karyotype forms were distinguished, involving subdivision of strain I into 3 types (A, B, C) and strain II into 2 types (D, E). The types A, B and C were mainly associated with isolates from rabbits of different geographical origins. The types D, E and F were characterized by a reduced chromosome size range, 2 of these appearing specific to a carnivorous host species (D in dog and F in blue fox). Hybridization experiments showed that all E. cuniculi isolates possess 11 chromosomes, with a size polymorphism entailing occasional electrophoretic comigration of heterologous chromosomes and differential migration of homologous ones. DNA rearrangements should occur during mitosis and the hypothesis of diploidy for the basic state of E. cuniculi seems likely.
Animals↗
High prevalence of Enterocytozoon bieneusi in swine with four genotypes that differ from those identified in humans.
The microsporidial species Enterocytozoon bieneusi is found among immunocompromised, particularly HIV-infected, patients with chronic diarrhoea, and rarely also among immunocompetent persons with self-limited diarrhoea. Only recently, E. bieneusi was detected in 4 pigs in Switzerland raising the question of a potential zoonotic nature of this parasite. We examined faecal samples of 109 pigs, 24 cows, horses and red foxes each for the presence of E. bieneusi by PCR and compared these isolates with isolates obtained from stool samples of 13 HIV-infected patients living in Switzerland. In animals, E. bieneusi was only identified in pigs with a prevalence of 35%. Analysis of the rDNA internal transcribed spacer (ITS) sequence allowed the classification of E. bieneusi from 28 pigs into 4 distinct genotypes which grouped very closely (identity 96.3-98.8%) together with 2 of the 3 human-derived E. bieneusi genotypes. Hence, E. bieneusi seems to be a common parasite in swine, but no genotypes were identified that were found in humans. Nevertheless, swine might serve as a new animal model for enterocytozoonosis.
Animals↗
[Nuclear magnetic resonance tomography after fatty tissue obliteration of the frontal sinus].
BACKGROUND: The osteoplastic flap procedure with fat obliteration has been hailed as the gold standard of definitive frontal sinus procedures for chronic inflammatory disease. The value of magnetic resonance imaging (MRI) in postoperative follow-up has not yet been sufficiently examined. METHODS: All postoperative MRI scans performed in patients undergoing surgery between January 1, 1986, and December 31, 1996 were evaluated. The outcome parameters were time-dependent changes in the distribution of fatty or connective tissue and development of necroses or oil cysts, as well as recurrences, inflammatory complications, or mucoceles. RESULTS: Sixty-eight operations were performed in the specified period and a total of 73 postoperative MRI scans from 45 operations were available for evaluation. In 16 cases, between two and five MRI scans were available. The individual time between surgery and the last MRI scan ranged from two weeks to 130 months with an average of 30.1 months. We found four mucoceles 34, 49, 106, and 130 months, respectively. Three of the mucoceles were diagnosed on the first postoperative MRI scan. In the fourth case the mucocele had not been seen on the previous scan. The amount of adipose tissue depictable on the last scan was less than 20% in the majority of cases (58%) and more than 60% in only 18% of cases, although in the latter group the time between surgery and MRI was less than 7 months in half the cases. CONCLUSIONS: MRI is the most valuable diagnostic tool after frontal sinus obliteration using adipose tissue. Despite the good soft tissue differentiation, the method has some limitations with regard to detection of small recurrent mucoceles and differentiation between vital adipose tissue and fat necrosis in the form of oil cysts. In these difficult cases, long-term MRI follow-up is necessary for definitive evaluation. We therefore recommend MRI 1, 2, and 5 years after osteoplastic frontal sinus surgery with obliteration.
Adipose Tissue↗
Influence of helical CT parameters on spatial resolution in CT angiography performed with a subsecond scanner.
RATIONALE AND OBJECTIVES: In helical CT, the beam collimation, table feed (TF) per tube rotation, voltage, current, reconstruction increment, kernel, linear interpolation algorithm (LIA), and contrast are variable parameters. The purpose of this study was to determine which of these parameters are most important to minimize partial volume effects for improving spatial resolution in CT angiography. METHODS: Phantom vessel stenoses of different lengths (2, 8 mm) and diameters (0.5, 1, 2, 3, 4 mm) were scanned with helical CT using a constant tube rotation time of 0.75 sec and 42 selected combinations of the above-mentioned parameters. Orthogonal targeted maximum intensity projections of the stenoses were ordered according to the increase in blurring and noise in a consensus reading by two radiologists blinded to the parameters used. RESULTS: Three millimeters of collimation and TF in conjunction with a 180 degrees LIA and > 250 Hounsfield unit contrast density was considered the optimal parameter combination and enabled a continuous visualization of the stenoses down to 0.5 mm in diameter. A collimation of 1 or 2 mm and 5 mm was considered inferior to a collimation of 3 mm because of, respectively, noise and blurring. With 3 mm collimation, significant blurring occurred when a pitch larger than 1.5 was used. A 3 mm collimation with a pitch of 2 (6 mm TF) was found to be superior to a collimation of 5 mm in conjunction with a pitch of 1 (5 mm TF). With 5 mm collimation, the short stenoses could be visualized only when using a 180 degrees LIA and a TF per tube rotation smaller than 7 mm. Eight and 10 mm collimations failed to depict the short stenoses. CONCLUSIONS: Collimation had the most influence on image quality in CT angiography, followed by LIA, pitch, and contrast density. Decreasing the reconstruction increment to less than one third of the TF or increasing the voltage or current beyond standard values did not improve the delineation of the stenoses. For screening examinations, the authors recommend the use of 3 mm collimation, 180 degrees LIA, and a pitch of 2.
Angiography↗
Surgical experience and complications during endonasal sinus surgery.
OBJECTIVE/HYPOTHESIS: The introduction of optical aids for endonasal sinus surgery has not produced the expected drop in the rate of serious intraoperative complications. STUDY DESIGN/METHODS: 1. Retrospectively, consecutive procedures of different surgeons were analyzed in regard to major complications (periorbital injury, orbital lesion, dural injury, endocranial lesion, damage to the internal carotid artery). The chronological distribution was transformed into a personal learning curve. 2. From our own experience and as surveyors, we analyzed the experiences of surgeons having encountered severe complications and compared them with the above-mentioned learning curve. RESULT: In total, 1,500 operations carried out by five surgeons with 16 serious complications were assessed. For the learning curve, the following stages were defined. stage I: greatest risk of complication, with dural injury (1st to 30th operation); stage II, slighter risk of complication, with frequent periorbital injuries (31st to 180th operation); and stage III, least risk, corresponding to an experienced surgeon. Serious complications occur most frequently among experienced surgeons. CONCLUSION: The beginner enjoys the most effective type of assistance, in the form of personal guidance of an experienced surgeon who is constantly present during the first 30 operations, and who should then be readily available during the next 70 operative procedures. The use of multimedia software appears to be helpful, though its actual value still remains to be determined. The experienced surgeon in particular must be willing to exercise repeated self-criticism to keep his or her rate of complications to a minimum.
Dura Mater↗
Performance characteristics of the BDProbeTec system for direct detection of Mycobacterium tuberculosis complex in respiratory specimens.
Strand displacement amplification (SDA) technology has been established in a fully automated system known as BDProbeTec. Target sequences of the insertion sequence IS6110 and the 16S rRNA gene are simultaneously amplified, which thus allows the detection of Mycobacterium tuberculosis complex and, as an additional option, of most Mycobacterium species. Detection occurs via a chemiluminescent microwell assay that employs the simultaneous hybridization and capture of SDA products with a biotinylated capture probe and an alkaline phosphatase detector probe. We have evaluated the performance of the BDProbeTec system in detecting M. tuberculosis complex by testing 799 respiratory specimens and comparing the results to those obtained by conventional diagnostic techniques, i.e. , microscopy and culture (solid and radiometric media). M. tuberculosis was cultivated from 41 specimens, of which 28 (68.4%) were smear positive and 13 (31.6%) were smear negative. The overall sensitivity of the SDA assay was 97.6% (for smear-positive specimens, 100%; for smear-negative specimens, 92.3%), and specificity was 95. 0%. After resolution of the discrepancies by studying the patients' clinical data, sensitivity and specificity were 97.9 and 96.5%, respectively, and positive and negative predictive values were 63.9 and 99.9%, respectively. These preliminary data demonstrate that the BDProbeTec system has promising performance characteristics with respiratory specimens and that it allows the detection of M. tuberculosis complex within hours.
Adult↗
Molecular evidence of coinfection of ticks with Borrelia burgdorferi sensu lato and the human granulocytic ehrlichiosis agent in Switzerland.
Adult Ixodes ricinus ticks were collected in Switzerland and tested for the presence of coinfection with Borrelia burgdorferi sensu lato and the human granulocytic ehrlichiosis (HGE) agent by real-time PCR. Of 100 ticks, 49% were positive for B. burgdorferi and 2% were positive for the HGE agent. The two HGE agent-positive ticks were also found to be positive for B. burgdorferi.
Animals↗
Highly sensitive methods for quantitation of human immunodeficiency virus type 1 RNA from plasma, cells, and tissues.
Precise and sensitive quantitation of viral RNA in specimens from human immunodeficiency virus (HIV) type 1 (HIV-1)-infected individuals has become an indispensable tool for the monitoring of the efficacy of highly active antiretroviral combination therapy. The present report describes reproducible and efficient protocols with enhanced sensitivity for quantitation of HIV-1 RNA from plasma, peripheral blood mononuclear cells, and tissues with Qiagen silica columns for RNA purification combined with the Roche Amplicor HIV-1 Monitor test for quantitative reverse transcription-PCR (RT-PCR). Extraction of RNA from 0.5 ml of plasma resulted in the detection of fewer than 20 HIV RNA copies/ml of plasma, equivalent to the centrifugation-based boosted RT-PCR assay. Silica extraction of cellular RNA resulted in the detection of fewer than 3 HIV-1 RNA copies/microg of total RNA. These techniques facilitate direct comparisons of viral loads between liquid and cellular specimens. Application of these sensitive methods may improve the assessment of the response to new antiretroviral regimens.
DNA Transposable Elements↗
Evidence of the human granulocytic ehrlichiosis agent in Ixodes ricinus ticks in Switzerland.
A total of 1,667 Ixodes ricinus ticks were collected from five regions in Switzerland where there have been sporadic occurrences of granulocytic ehrlichiosis in dogs and horses. The ticks were examined for rickettsiae of the Ehrlichia phagocytophila group via nested PCR. Twenty-one ticks (1.3%) were positive; 3 (0.5%) were nymphs, 6 (1.3%) were adult males, and 12 (1.9%) were adult females. The number of positive ticks varied with the stage of development and with the geographical origin. Nucleotide sequencing of the isolated PCR products identified these products as part of the 16S rRNA gene of Ehrlichia. In addition, these products had 100% homology with the agent of human granulocytic ehrlichiosis. The occurrence of this agent in I. ricinus in Switzerland presents a potential danger of transmission of granulocytic ehrlichiosis to dogs, horses, and humans.
Animals↗
Mutations in the COL5A1 coding sequence are not common in patients with spontaneous cervical artery dissections.
BACKGROUND AND PURPOSE: The dermal connective tissue of most patients with spontaneous cervical artery dissections (sCAD) contains abnormal collagen fibers. This suggests a predisposing connective tissue defect. The ultrastructural abnormalities in the skin of patients with sCAD have similarity with the morphological alterations in patients with Ehlers-Danlos syndrome type II, a dominant hereditary disorder that has been correlated in some patients to mutations within the genes encoding type V collagen. The aim of this study was to assess the alpha 1 chain of type V collagen (COL5A1) as a candidate gene for sCAD. METHODS: We searched for mutations in the COL5A1 gene in cDNA from cultured fibroblasts of 19 patients with sCAD using single-strand conformational polymorphism analysis and nucleotide sequence analysis of polymerase chain reaction-amplified fragments of the whole COL5A1 coding sequence. RESULTS: We detected 1 missense mutation leading to a predicted amino acid (192D/N) substitution within the N-terminal propeptide in 2 siblings. All other patients showed regular COL5A1 sequences with some silent polymorphisms. CONCLUSIONS: Mutations in the COL5A1 gene do not appear to be a major factor in the etiology of sCAD.
Adult↗
Obliteration of the frontal sinus--state of the art and reflections on new materials.
Despite increasing advances in endonasal frontal sinus surgery, obliteration of the frontal sinus is necessary in some cases for definitive clearing frontal sinus pathology. Reviewing the literature and considering pathophysiological aspects, successful obliteration of the frontal sinus depends on the complete removal of the mucosa and a sufficient closure of the nasofrontal duct, but not on the material used for obliteration, if special considerations are taken into account and foreign materials are avoided. Complete removal of the mucosa has to include removal of the inner bony cortex of the frontal bone. Occlusion of the nasofrontal duct is achieved with a sufficiently fixed fibrous layer.
Adipose Tissue↗
Videoendoscopic analysis of nasal steroid distribution.
Topical corticosteroids are one of the main pillars in the treatment of nasal polyps. The exact topography of their intranasal deposition has not yet been adequately visualised. The intranasal distribution of a 1% sodium fluorescein solution applied with original Pulmicort Topinasal (budesonide) metered pump bottles was analysed by videoendoscopy. The study group included eight healthy subjects and ten patients who had undergone endonasal sinus surgery. Videoendoscopy was performed in the study group within the first minute after application of the fluorescein solution. Additionally the deposition pattern of Pulmicort Topinasal was analyzed using a nasal model. The examination showed that the majority of the substance is deposited on the anterior portion of the nasal septum and the head of the inferior turbinate. Only a small fraction actually reaches the middle meatus. The distribution is improved by application during the decongested phase of the nasal cycle, after use of vasoconstricting nasal drops and maintaining a spraying angle of 45 degrees upwards. The development of new delivery techniques and systems could improve the efficacy of intranasally administered corticosteroids and reduce the complication rate.
Administration, Intranasal↗
[Cardiovascular rehabilitation and prevention. Specific training for nurses?].
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Curriculum↗
Highly active antiretroviral therapy during early HIV infection reverses T-cell activation and maturation abnormalities. Swiss HIV Cohort Study.
OBJECTIVES: To evaluate the impact of early initiation of highly active antiretroviral therapy (HAART) on disease-induced T-cell activation and maturation abnormalities during asymptomatic HIV infection. DESIGN: A prospective open-label trial of zidovudine, lamivudine and ritonavir in treatment-naive asymptomatic HIV-infected individuals with CD4 cells > or = 400 x 10(6)/l. METHODS: Peripheral blood CD4+ and CD8+ T cells derived from 15 asymptomatic HIV-infected individuals (median baseline CD4+ cells, 608 x 10(6)/l; CD8+ cells, 894 x 10(6)/l; plasma HIV RNA, 3.93 log10 copies/ml) undergoing therapy with zidovudine (300 mg twice daily), lamivudine (150 mg twice daily), and ritonavir (600 mg twice daily) were assessed for changes in expression of phenotypic markers of T-cell activation (HLA-DR and CD38) and maturation (CD45RA and CD45RO). At weeks 0, 2, 4, 8, 12, 16, 20 and 24, T-cell subsets were quantified by flow cytometry and plasma HIV viral loads determined using reverse transcription PCR. RESULTS: HAART-induced decrease in plasma HIV RNA levels coincided with a significant reduction in numbers of activated CD4+/HLA-DR+ (maximum change, -36%; P < or = 0.05), CD8+/HLA-DR+ (maximum change, -66%; P < or = 0.005) and CD8+/CD38+ (maximum change, -51%; P < or = 0.01) T cells. A concomitant significant increase in numbers of naive CD4+/CD45RA+ (maximum change, +12%; P < or = 0.005) and memory CD4+/CD45RO+ (maximum change, +6%; P < or = 0.05) T cells was also evident, which contrasted with a significant decrease in memory CD8+/CD45RO+ cells (maximum change, -42%; P < or = 0.005). CONCLUSION: The observed ability of HAART during early asymptomatic HIV infection to initiate rapid reversal of disease-induced T-cell activation and maturation abnormalities, while preserving pretherapy levels of immune function, supports the concept that therapeutic advantage is to be gained by commencing early aggressive antiretroviral therapy.
ADP-ribosyl Cyclase↗