Increase of nucleoid size with increasing age of hyphal region in vegetative mycelia of Streptomyces granaticolor

In mycelia of Streptomyces granaticolor grown in liquid cultures the distribution of DNA was surveyed by staining and autoradiographic methods. The frequency of stained nucleoids was rather similar in young and old hyphal regions. However, the size of the nucleoids increased with the age of a hyphal region. The degree of heterogeneity in nucleoid size was particularly high during slow growth. In the autoradiograms silver grains (³H-thymidine label) were also heterogeneously distributed along the hyphae. Calculation of the average number of silver grains per nucleoid revealed that the amount of DNA per nucleoid was 1.6 times higher in the more distant subapical regions than within the 35 μm long apical region. From a chase experiment it became obvious that the DNA segregated in a normal manner only within the apical region. When the chase lasted for one doubling time, the frequency of silver grains was reduced to 50% only within the about 30 μm long apical region. The label incorporated subapieally remained almost constant, therefore, indicating a lack of normal segregation. Only about 10% of the label was lost by branching. The lack of segregation of sister nucleoids after repeated rounds of replication was found to be responsible for the increase of nucleoid size within subapieal hyphal regions.     

Metabolism of aniline and 3-chloroaniline in Pseudomonas acidovorans CA28: Evidence of isofunctional muconate cycloisomerases

Two distinct muconate cycloisomerases are involved in the degradation of aniline and 3-chloroaniline (3-CA) proceeding via the ortho-cleavage pathways in Pseudomonas acidovorans CA28. After partial purification of these two enzymes kinetic investigations resulted in a clear differentiation of aniline-derived muconate cycloisomerase (MC) and 3-CA-derived chloromuconate cycloisomerase (CMC). A further result of this study revealed the simultaneous coexistence of MC and CMC in strain CA28 when grown on a mixture of aniline and 3-CA.     

Biocompatibility of surgical-grade dense polycrystalline alumina.

This article reviews the knowledge about biocompatibility of alumina since its introduction as a material for use in joint replacements. Alumina is a hydrophilic material with high wettability allowing very low friction with negligible wear. Macrophages loaded with alumina particles show no morphologic alteration and do not lose their chemotactic ability. The host response has been studied for bulk and particulate alumina in soft tissues, as well as in human and animal bone under loaded and nonloaded conditions. The soft-tissue response to bulk alumina exhibits minimal fibrosis, and direct bone contact is achieved at compression-loaded interfaces. Examination of human biopsies from failed total hip prostheses reveals a foreign-body reaction containing predominantly macrophages loaded with alumina particles. No lymphocyte or plasma-cell infiltration is observed because of the absence of soluble component release. The amount of necrosis and fibrosis was lower than that associated with metal or polyethylene debris. In summary, alumina exhibits greater bioinertness than all other implant materials currently available for joint replacement.     

Probleme bei gynäkologischen Endoskopien aus der Sicht der Gynäkologie und Anästhesiologie

Zum Thema Die Endoskopie hat in der operativen Gyn?kologie in den letzten Jahren zunehmend an Bedeutung gewonnen. Neben ihrem Einsatz in der Diagnostik werden auch operativ-therapeutische Eingriffe immer h?ufiger endoskopisch vorgenommen. In vielen F?llen kann dadurch eine Laparotomie mit ihren Risiken und postoperativen Problemen und der damit verbundenen l?ngeren postoperativen Hospitalisation vermieden werden. Auch bei endoskopischen Eingriffen k?nnen schwerwiegende operative Komplikationen auftreten wie z. B. Blutungen oder Verletzungen von Nachbarorganen wie Darm, Blase, Ureter, Magen [8, 16, 17, 21]. Darüber hinaus kommt es durch die Anlage des Pneumoperitoneums und die Lagerung der Patientinnen bei der Laparoskopie und durch den Einsatz von Spüll?sungen bei der operativen Hysteroskopie zu pathophysiologischen Ver?nderungen, deren Kenntnis für Operateur und An?sthesist zur Vermeidung von Komplikationen unabdingbar ist [18, 25].     

High prevalence of hepatitis C virus type 5 in central France evidenced by a prospective study from 1996 to 2002

From 1996 to 2002, hepatitis C virus (HCV) typing was prospectively performed for 1,281 unselected HCV-infected and viremic patients, irrespective of their clinical status. Eighty-three patients (6.5%) were coinfected with human immunodeficiency virus (HIV) and HCV. A total of 1,195 strains were identified by a serotype screening (Murex HCV Serotyping 1-6 assay) and/or genotyping (Inno-LiPA HCV II) test. The distribution of HCV types showed an unusually high rate of type 5 (14.2%) that was stable over time and was the third most frequent type, after type 1 (59.1%) and type 3 (15.1%). HCV type 5 was more frequent in patients who were older than 50 (P = 10(-6)), but its frequency did not differ significantly by gender (P = 0.21). Serotyping was performed for 1,160 strains but failed for 30.2% of them. The efficiency depended on HIV status (for HCV-HIV-coinfected patients, half of the strains were untypeable) and HCV type. Genotyping was performed for 428 samples, with an overall efficiency of 99.3%. It failed in three cases, which were subsequently identified as HCV type 2. Serotyping and genotyping results for 39 patients showed discrepancies between the two methods for 4 patients, who had HCV type 2, type 6, or mixed infections. Thus, HCV type 5 may also be encountered frequently in Western countries. Its apparent confinement to a restricted area raises the question of how it emerged and underscores the need for further studies of HCV type prevalence, routes of transmission, pathogenicity, and responses to treatment.     

Molecular epidemiology of Pseudomonas aeruginosa colonization in a burn unit: persistence of a multidrug-resistant clone and a silver sulfadiazine-resistant clone

To study the epidemiology of Pseudomonas aeruginosa colonization in a 32-bed burn wound center (BWC), 321 clinical and 45 environmental P. aeruginosa isolates were collected by prospective surveillance culture over a 1-year period and analyzed by serotyping, drug susceptibility testing, and amplified fragment length polymorphism (AFLP) analysis. Among 441 patients treated at the center, 70 (16%) were colonized with P. aeruginosa, including 12 (17%) patients who were colonized on admission and 58 (83%) patients who acquired the organism during their stay. Of the 48 distinct AFLP genotypes found, 21 were found exclusively in the environment, 15 were isolated from individual patients only, and 12 were responsible for the colonization of 57 patients, of which 2 were also isolated from the environment, but secondary to patient carriage. Polyclonal P. aeruginosa colonization with strains of two to four genotypes, often with different antibiotic susceptibility patterns, was observed in 19 patients (27%). Two predominant genotypes were responsible for recurrent outbreaks and the colonization of 42 patients (60% of all colonized patients). The strain with one of those genotypes appeared to be endemic to the BWC and developed multidrug resistance (MDR) at the end of the study period, whereas the strain with the other genotype was antibiotic susceptible but resistant to silver sulfadiazine (SSD(r)). The MDR strain was found at a higher frequency in sputum samples than the SSD(r) strain, which showed a higher prevalence in burn wound samples, suggesting that anatomic habitat selection was associated with adaptive resistance to antimicrobial drugs. Repeated and thorough surveys of the hospital environment failed to detect a primary reservoir for any of those genotypes. Cross-acquisition, resulting from insufficient compliance with infection control measures, was the major route of colonization in our BWC. In addition to the AFLP pattern and serotype, analysis of the nucleotide sequences of three (lipo)protein genes (oprI, oprL, and oprD) and the pyoverdine type revealed that all predominant strains except the SSD(r) strain belonged to recently identified clonal complexes. These successful clones are widespread in nature and therefore predominate in the patient population, in whom variants accumulate drug resistance mechanisms that allow their transmission and persistence in the BWC.     

Different calcium phosphate bioglass ceramics implanted in rabbit cortical bone. An interface study

In order to study the interface of calcium phosphate bioglass ceramics, cylinders of standard size were implanted in the tibiae of rabbits. The materials were evaluated by radiography, light microscopy and microradiography. Bioceramics with hydroxyapatite surface give rise to a closer contact with new bone than calcium phosphate glass ceramics.