A group of specialized genes has been defined to govern the molecular mechanisms controlling the circadian clock in mammals. Their expression and the interactions among their products dictate ...circadian rhythmicity. Three genes homologous to Drosophila period exist in the mouse and are thought to be major players in the biological clock. Here we present the generation of mice in which the founding member of the family, Per1, has been inactivated by homologous recombination. These mice present rhythmicity in locomotor activity, but with a period almost 1 h shorter than wild‐type littermates. Moreover, the expression of clock genes in peripheral tissues appears to be delayed in Per1 mutant animals. Importantly, light‐induced phase shifting appears conserved. The oscillatory expression of clock genes and the induction of immediate‐early genes in response to light in the master clock structure, the suprachiasmatic nucleus, are unaffected. Altogether, these data demonstrate that Per1 plays a distinct role within the Per family, as it may be involved predominantly in peripheral clocks and/or in the output pathways of the circadian clock.
Invasive aspergillosis is a life-threatening fungal infection which, in neutropenic patients, is associated with an extremely high mortality rate despite optimal treatment. In order to investigate ...microbiological risk factors for treatment failures in more detail, Aspergillus spp. obtained from 29 patients with haematological diseases after myelo-ablative chemotherapy and bone marrow transplantation were analysed for their susceptibility to amphotericin B in vitro and this was compared with clinical outcome to see if there was a correlation. Aspergillus flavus was present in 12 (41 %) of the 29 patients, Aspergillus terreus in nine (31%) and Aspergillus fumigatus in eight (28%). The susceptibility of these isolates to amphotericin B varied between and within the three species. A. terreus was the only organism against which the MIC was consistently high, A. fumigatus and A. flavus showing variation between isolates in the degree of resistance to amphotericin B. The degree of in-vitro resistance was the only parameter correlating with clinical outcome in a univariate analysis and the only prognostic value in a multivariate analysis considering known risk factors. Irrespective of the species, all six patients with isolates against which the MIC was <2 mg/L survived, whereas most (22/23) of those with isolates resistant to > or = 2 mg/L died. Infections among the six survivors were caused by amphotericin B-susceptible A. fumigatus and A. flavus, but not A. terreus. We conclude that the outcome of aspergillus infection depends on the in-vitro susceptibility of the isolates to amphotericin B. Survival was poor in patients with isolates resistant to amphotericin B and good in those with amphotericin B-susceptible specimens. A. terreus was always associated with high resistance to amphotericin B and with poor survival.
The medicinal system of the Asháninka Indians in Perú is portrayed. Three categories of medical disorders and healers are recognized. A human is viewed to consist of a physical and a spiritual being ...who communicate with each other by means of a regulating element. The significance of Uncaria tomentosa (Willd.) DC. (Rubiaceae), locally known as unã de gato, in traditional medicine is emphasized by its exclusive use by priests to influence this regulation. Pharmacological and toxicological results obtained with extracts or isolated compounds are summarized. Pentacyclic oxindole alkaloids stimulate endothelial cells in vitro to produce a lymphocyte-proliferation-regulating factor. Tetracyclic oxindole alkaloids act as antagonists. A significant normalization of lymphocyte percentage was observed in vivo although total leucocyte numbers did not change.
Retinoic acid (RA) plays a critical role in normal development, growth, and maintenance of certain tissues. The action of RA is thought to be mediated in part by the three nuclear receptors (RARα, ...-β, and -γ), each of which is expressed as multiple isoforms. To investigate the function of the RARα gene, we have disrupted, in the mouse, the whole gene or the isoform RARα 1. Although RARα 1 is the predominant isoform and is highly conserved among vertebrates, RARα 1-null mice appeared normal. However, targeted disruption of the whole RARα gene resulted in early postnatal lethality and testis degeneration. These results, showing that RARα is indeed involved in the transduction of the RA signal, also suggest an unexpected genetic redundancy.
Aspergillus terreus appears to have become an increasingly frequent cause of opportunistic infections in the University Hospital of Innsbruck (UHI) and is of serious concern because of in vivo and in ...vitro resistance to amphotericin B. In order to determine the possible relationship between environmental contamination by A. terreus and the occurrence of invasive aspergillosis, a 1-year prospective study (2004–2005) was carried out in the UHI. Isolates obtained from air samples of various high-risk settings and those from surveillance cultures of proven and probable aspergillosis (EORTC/MSG criteria) were examined by genotyping. Within 1 year, 34 and 15 A. terreus isolates were collected from the environment and from patients, respectively. Genotypic analysis with rapid amplification of polymorphic DNA (RAPD) PCR and the combination of three different primers (R108, CII, P4) revealed 46 distinct genotypic profiles (types 1–46). No strain similarity was detected among and within the patients and environmental areas, indicating a great genomic diversity in A. terreus, which is common in the environment of Innsbruck and a source of invasive infections in immunosuppressed patients. Genotypical diversity was found in clinical and environmental A. terreus isolates.
The mechanisms that maintain the epithelial integrity of the gastrointestinal tract remain largely undefined. The gene encoding intestinal trefoil factor (ITF), a protein secreted throughout the ...small intestine and colon, was rendered nonfunctional in mice by targeted disruption. Mice lacking ITF had impaired mucosal healing and died from extensive colitis after oral administration of dextran sulfate sodium, an agent that causes mild epithelial injury in wild-type mice. ITF-deficient mice manifested poor epithelial regeneration after injury. These findings reveal a central role for ITF in the maintenance and repair of the intestinal mucosa.
During a three-year period nine patients with haematological diseases after myeloablative chemotherapy died from invasive fungal infections caused by Aspergillus terreus. The hospital inanimate ...environment was monitored andA. terreus was cultured from potted plants in the vicinity of the patients. The patients (N= 14) and the environmental isolates (N= 2) were fingerprinted by RAPD-PCR with four different primers. Based on RAPD patterns the patients' isolates were differentiated into five different types; the environmental isolates represented two types. The isolates of four patients were identical to those found in the environment. Five additional patients were infected by RAPD types not found in the environment. One patient was infected with two different types. The data indicate a hospital-acquired infection in many of the patients and underline the need for careful environmental monitoring of units in which high-risk patients are housed.
Stromelysin-3 (ST3; Basset, P., J.P. Bellocq, C. Wolf, I. Stoll, P. Hutin, J.M. Limacher, O.L. Podhajcer, M.P. Chenard, M.C. Rio, P. Chambon. 1990. Nature. 348:699-704) is a matrix metalloproteinase ...(MMP) expressed in mesenchymal cells located close to epithelial cells, during physiological and pathological tissue remodeling processes. In human carcinomas, high ST3 levels are associated with a poor clinical outcome, suggesting that ST3 plays a role during malignant processes. In this study we report the ST3 gene inactivation by homologous recombination. Although ST3 null mice ( ST3-/-) were fertile and did not exhibit obvious alterations in appearance and behavior, the lack of ST3 altered malignant processes. Thus, the suppression of ST3 results in a decreased 7,12-dimethylbenzan-thracene-induced tumorigenesis in ST3-/- mice. Moreover, ST3-/- fibroblasts have lost the capacity to promote implantation of MCF7 human malignant epithelial cells in nude mice (P < 0.008). Finally, we show that this ST3 paracrine function requires extracellular matrix (ECM)-associated growth factors. Altogether, these findings give evidence that ST3 promotes, in a paracrine manner, homing of malignant epithelial cells, a key process for both primary tumors and metastases. Therefore, ST3 represents an appropriate target for specific MMP inhibitor(s) in future therapeutical approaches directed against the stromal compartment of human carcinomas.
Summary
Aspergillus terreus, a less common pathogen, appears to be an emerging cause of infection at our institution, the Medical University Hospital of Innsbruck. Thus the epidemiology and outcome ...of A. terreus infections over the past 10 years was assessed. We analysed 67 cases of proven invasive aspergillosis (IA) according to the European Organisation for Research and Treatment of Cancer/Mycoses Study Group criteria, investigated antifungal susceptibility of amphotericin B (AMB), voriconazole and caspofungin and performed molecular typing of A. terreus. Patients with proven IA caused by A. terreus (n = 32) and non‐A. terreus (n = 35) were evaluated. The two groups were comparable in terms of age, gender, underlying disease, antifungal prophylaxis and duration of neutropenia (P > 0·05). Leukaemia was the most common underlying malignancy. Fungal dissemination occurred in 63% of the patients. Aspergillus terreus infections were associated with a lower response rate to AMB therapy (20%), compared with 47% for patients with non‐A. terreus infections (P < 0·05). In vitro, A. terreus was found to be resistant to AMB and molecular typing discriminated between patients isolates, showing a high strain diversity with 26 distinct types (I‐XXVI) identified by combination of three primers. Aspergillus terreus infections displayed evidence of AMB resistance in vitro and in vivo and were associated with a high rate of dissemination and poor outcome; A. terreus causes systemic infections of endemic character in Tyrol, Austria. The onset of A. terreus infection depends not on the degree of immunosuppression but on environmental Aspergillus spp. exposure.
There is no consensus regarding the benefit versus harm of antibiotic therapy for treatment of disease due to enterohemorrhagic Escherichia coli O157. The effects in vitro of subinhibitory ...concentrations of 13 antimicrobial agents on the release of Shiga toxin (Stx) by three different Escherichia coli O157 strains expressing Stx 1 or Stx 2 either alone or in combination were investigated. The Stx-induced cell death of Vero cells was determined using a colorimetric assay based on the measurement of lactate dehydrogenase (LDH) released into the supernatant from the cytosol of damaged cells. Growth of all O157 strains in broth cultures containing subinhibitory concentrations of cotrimoxazole, trimethoprim, azithromycin, or gentamicin was accompanied by a marked increase in the release of Stx. Exposure to cefixime, ceftriaxone, or erythromycin caused a marked increase in the release of Stx by the O157 strain producing Stx 2 alone, but decreased toxin production was observed with the Stx 1 producer and the strain producing Stx 1 and Stx 2. Exposure to ampicillin caused increased Stx release in the Stx 2-producing strain but had no effect on Stx production in the other two test isolates. Exposure to penicillin G, streptomycin, ciprofloxacin, fosfomycin, or sulfamethoxazole caused an increase in toxin production in two of the three test strains in each case, while decreases were observed for the other isolates. The response of Escherichia coli O157 isolates to subinhibitory concentrations of antibiotics seems to be highly dependent on the nature of the strain involved.
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