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Biomedical subjects

H Haas

Publications and source records attributed to H Haas.

At least 19 recordsLinked to original sources
PubMed2006

[Management of intussusception in France in 2004: investigation of the Paediatric Infectious Diseases Group, the French Group of Paediatric Emergency and Reanimation, and the French Society of Paediatric Surgery].

OBJECTIVES: To describe the different pathways of management of intussusception (IS) in infants and children in metropolitan France and to identify paediatric emergency centres that might constitute a surveillance network for IS. MATERIAL AND METHODS: A questionnaire was sent to 273 paediatric emergency centres distributed across France in 2005. Modalities of diagnosis and treatment of IS had to be precised. RESULTS: One hundred and sixty-seven centres (61.2%) responded. The response was given by 131 paediatricians (78.4%) and 36 surgeons (21.6%) working in 38 universitary hospitals (22.7%) and 129 general hospitals (77.2%). The mean number of IS treated in each centre in 2004 was 11+/-13.5 (extr. 0 to 70; median 6). Diagnosis of IS required a collaboration between medical and surgical teams in 51.5% of the centres, but in 40.1% the sole medical team was in charge of the diagnosis. Ultrasonography is used for diagnosis by 98.8% of the centres. Reduction with hydrostatic enema and eventually surgery was performed in the same hospital in 44.3%. Other centres systematically or frequently transferred the patients for reduction, mostly towards universitary hospitals (90%). CONCLUSION: The procedures of IS diagnosis are the same everywhere in France but the pathways of therapeutic management do vary, depending on the availability of surgeons and anaesthetists trained in paediatrics on each site. These disparities will probably change with the implementation of the new plan for sanitary organization in children and adolescents in France. Labellized paediatric emergency centres will gather more surgical patients and could eventually constitute an effective surveillance network for IS.

Acute Disease↗
PubMed2006

IPSE/alpha-1: a major immunogenic component secreted from Schistosoma mansoni eggs.

During infection with Schistosoma mansoni the egg stage of this parasite modulates the initial T helper (Th1) response into a Th2 response. This suggests that schistosome eggs contain factors responsible for that effect. We have recently described a glycoprotein (IPSE) from S. mansoni eggs that has a potent IL-4-inducing effect on human basophils. Here we demonstrate that IPSE is identical to a previously described molecule, the S. mansoni egg antigen alpha-1. We furthermore show that the expression of IPSE/alpha-1 at the level of both mRNA and protein is restricted to the egg stage. IPSE/alpha-1 is produced in and released from the subshell area of the egg and comes into close contact with inflammatory cells recruited to the vicinity of the egg surface. In line with this IPSE/alpha-1 is one of three major S. mansoni egg glycoproteins that induce pronounced antibody responses. Its IL-4-inducing capacity, moreover, suggests that IPSE/alpha-1 plays a role in initiating the Th2 response induced by patent S. mansoni infections.

Animals↗
PubMed2006

In contrast to specific B cells, human basophils are unaffected by the toxic activity of an allergen toxin due to lack of internalization of immunoglobulin E-bound allergen.

BACKGROUND: Specific immunotherapy is the only curative therapy for type I allergies and the alarming increase in allergy prevalence emphasizes the need for additional/alternative strategies for curative treatment. Allergen toxins (AT), fusion products of an allergen with an apoptosis inducing cytotoxin, are a new kind of immunotoxin. OBJECTIVE: AT should allow allergen-specific targeting and elimination of allergy-relevant cells, with B cells being the primary target. An important question is the fate of the effector cells, e.g. mast cells and basophils, which carry allergen-specific IgE: the immunotoxin might even prove to be harmful. METHODS: We established a reliable in vitro B cell model (using two mouse hybridoma cell lines) for testing specificity and toxicity of P5-ETA', a fusion protein of the major timothy grass pollen allergen Phl p 5b and truncated Pseudomonas Exotoxin A. In a second step, we investigated the impact of the AT on human basophils. RESULTS: P5-ETA' reliably eliminated Phl p 5-specific cells in the in vitro B cell model, leaving unspecific B cells unharmed. Human basophils of grass pollen allergic donors specifically bound P5-ETA', released IL-4 and up-regulated the activation marker CD203c, but were not subject to the toxic effect because of lack of internalization of IgE-bound allergen. CONCLUSION: According to our data, basophils are pure effector cells in the context of IgE-bound allergen and not involved in classical antigen presentation.

ADP Ribose Transferases↗
PubMed2005

[Antibiotherapy in children with atypical bacterial infections].

Atypical bacteria responsible for infections in children are mainly Mycoplasma pneumoniae, Chlamydia pneumoniae and Legionella pneumophila. Atypical pneumonia is a frequent disease in children. Until recently, the outcome was thought to be rather benign and antibiotherapy to have only a minor impact on the prognosis. Recent studies have demonstrated that M. pneumoniae and C. pneumoniae were involved in a variety of infections, including acute upper airway disease, otitis and pharyngitis under five. Antibiotherapy was proven able to decrease the rate of complications and recurrence, notably episodes of wheezing and exacerbations of asthma. Atypical bacteria infections may be severe in immunocompromised children and children with underlying disease such as sickle cell anaemia. Whenever bacteriological documentation is lacking, one of the critical issues in choosing an antibiotic is to consider its activity against Streptococcus pneumoniae, especially in lower respiratory tract infections. The main available molecules are reviewed and discussed, with a special emphasis on ketolides, a newer family of molecules active on both atypical bacteria and S. pneumoniae.

Anti-Bacterial Agents↗
PubMed2005

Amino-bisphosphonates in heterotopic ossification: first experience in five consecutive cases.

STUDY DESIGN: Retrospective, observational study in five consecutive cases. OBJECTIVES: The management of heterotopic ossification (HO), a frequent complication after spinal cord injury (SCI) and after orthopaedic surgery, is a therapeutic challenge with high recurrence rates of over 50%. Conflicting data were reported for Etidronate. The use of the more potent new generation of amino-bisphosphonates has been put forward in different inflammatory, dysmorphogenic bone disease. In order to try and halt the underlying dysfunctional bone metabolism we have studied the action of pamidronate in five consecutive high-risk patients with established HO of different etiology undergoing surgical removal. SETTING: University Hospital of Basel, Switzerland, Division of Endocrinology, Diabetology and Clinical Nutrition and the Department of Orthopedic Surgery. METHODS: In all five patients, ranging from 47 to 68 years of age, we used continuous pamidronate infusions perioperatively at a dosage of 120 mg in the first 12 h and subsequent reduction to 75-60-30-15 mg/12 h over a period of 10-14 days. RESULTS: None of these patients showed clinical, radiographical and laboratory signs of HO recurrence or new forming HO in the follow-up 5-54 month after surgery. Potential side effects of high-dose bisphosphonate therapy such as osteoporosis and osteomalacia were not reported in any case. CONCLUSION: We postulate that pamidronate might have pronounced beneficial effects in high-risk patients with established HO undergoing excision surgery. Since the therapeutic window of amino-bisphosphonates has not yet been defined and the minimal necessary doses for preventing new HO are unknown, further studies are encouraged to confirm our findings and to identify the necessary dosage and duration of treatment and to pinpoint, which patients will benefit most from this treatment.

Aged↗
PubMed2005

[Teaching outpatient medicine at urological congresses].

In Germany there is a two-track system for treatment of patients by specialists: severe diseases are treated in hospitals, less severe ones in outpatient practices/physicians' offices. Further training of specialist physicians must take both points of view into consideration. This task is not easy because specialists from university are most suitable as teachers, but they seldom have their own experience with the patients in outpatient offices (Praxis) and their less severe problems. The aim of this investigation was carry out an analysis of relevant structures, to improve them and to develop a new kind of further training. Our own data quantify the differences between these institutions with regard to the severity of the disease and the diagnosis. Topics of outpatient medicine are insufficiently represented in traditional congresses and doctors with outpatient practices too seldom take part in these congresses. They were questioned about their wishes with regard to topics of training/education, suitable dates and organisational structures. Practicing urologists expressed a desire for science and hints for outpatient medicine, organised in the form of seminars. Our way to organise such seminars, planned and conducted by urologists in outpatient practices is described and discussed and we report our experience.

Ambulatory Care↗
PubMed2004

[Type of child care and nasopharyngeal S. pneumoniae and H. influenzae carriage in children in the Alpes-Maritimes].

OBJECTIVE: To compare the prevalence rates of nasopharyngeal carriage of Streptococcus pneumoniae (SP) and of SP with diminished susceptibility to penicillin (PDSP) according to two types of day care, i.e. children in group day-care (GDC) and those attended by a child minder (CM) before and after the implementation of a local public health campaign promoting prudent antibiotic use in pediatric care. METHODS: Two cross sectional studies were conducted in each care setting in 1999, 2000 and 2002, on a random sample of children. RESULTS: Initial prevalence rates for SP before the campaign were 54% in the GDC group in 1999 and 34% in the CM group in 2000, with 63% and 52% PDSP, respectively. In 2002 theses rates were 58 and 33% for SP (p<10(-5)) and 64 and 53% for PDSP, respectively. The proportion of children who received antibiotics decreased in both care settings between the two surveys, from 47 to 37% in the CM group (p=0.03) and from 60 to 51% in the GDC group (p=0.03). CONCLUSION: These results are in favor of the child minder setting and also illustrate the positive impact of a public health campaign on the frequency of antibiotic prescriptions.

Anti-Bacterial Agents↗
PubMed2004

Small angle x-ray scattering from lipid-bound myelin basic protein in solution.

The structure of myelin basic protein (MBP), purified from the myelin sheath in both lipid-free (LF-MBP) and lipid-bound (LB-MBP) forms, was investigated in solution by small angle x-ray scattering. The water-soluble LF-MBP, extracted at pH < 3.0 from defatted brain, is the classical preparation of MBP, commonly regarded as an intrinsically unfolded protein. LB-MBP is a lipoprotein-detergent complex extracted from myelin with its native lipidic environment at pH > 7.0. Under all conditions, the scattering from the two protein forms was different, indicating different molecular shapes. For the LB-MBP, well-defined scattering curves were obtained, suggesting that the protein had a unique, compact (but not globular) structure. Furthermore, these data were compatible with earlier results from molecular modeling calculations on the MBP structure which have been refined by us. In contrast, the LF-MBP data were in accordance with the expected open-coil conformation. The results represent the first direct structural information from x-ray scattering measurements on MBP in its native lipidic environment in solution.

Computer Simulation↗
PubMed2004

Echinococcus multilocularis metacestode extract triggers human basophils to release interleukin-4.

Infections with parasitic helminths are associated with a T helper 2 (Th2) immune response and IgE production. The underlying mechanism, however, is only partially understood. Recently we have isolated a protein from extracts of Schistosoma mansoni eggs that triggers human basophils from non-sensitized donors to release interleukin-4 (IL-4), the key cytokine of a Th2 response. We called this protein IPSE (for IL-4-inducing principle from Schistosoma mansoni eggs). Supposing that IPSE-like IL-4-inducing activities might be a general principle shared among different helminth species, we investigated extracts from the cestode E. multilocularis for its effect on human basophils. Our results showed that extracts from metacestodes of E. multilocularis cause basophil degranulation, as well as the secretion of histamine, IL-4 and IL-13, in a dose-dependent manner. IgE stripping and resensitization of basophils indicated that the mechanism of IL-4 induction requires the presence of IgE on the cells. Since analogous properties have been demonstrated earlier for IPSE, we think that S. mansoni and E. multilocularis may induce a Th2 response in their hosts via a related mechanism, namely, by the induction of IL-4 release from basophils.

Animals↗
PubMed2004

Penicillium chrysogenum glucose oxidase -- a study on its antifungal effects.

AIMS: Purification and characterization of the high molecular mass Candida albicans-killing protein secreted by Penicillium chrysogenum. METHODS AND RESULTS: The protein was purified by a combination of ultrafiltration, chromatofocusing and gel filtration. Enzymological characteristics [relative molecular mass (M(r)) = 155 000, subunit structure alpha(2) with M(r,alpha) = 76 000, isoelectric point (pI) = 5.4] were determined using SDS-PAGE and 2D-electrophoresis. N-terminal amino acid sequencing and homology search demonstrated that the antifungal protein was the glucose oxidase (GOX) of the fungus. The enzyme was cytotoxic for a series of bacteria, yeasts and filamentous fungi. Vitamin C (1.0 mg ml(-1)) prevented oxidative cell injuries triggered by 0.004 U GOX in Emericella nidulans cultures but bovine liver catalase was ineffective even at a GOX : catalase activity ratio of 0.004 : 200 U. A secondary inhibition of growth in E. nidulans cultures by the oxygen-depleting GOX-catalase system was likely to replace the primary inhibition exerted by H(2)O(2). CONCLUSIONS: Penicillium chrysogenum GOX possesses similar enzymological features to those described earlier for other Penicillium GOXs. Its cytotoxicity was dependent on the inherent antioxidant potential of the test micro-organisms. SIGNIFICANCE AND IMPACT OF THE STUDY: Penicillium chrysogenum GOX may find future applications in glucose biosensor production, the disinfection of medical implants or in the food industry as an antimicrobial and/or preservative agent.

Amino Acids↗
PubMed2003

Molecular genetics of fungal siderophore biosynthesis and uptake: the role of siderophores in iron uptake and storage.

To acquire iron, all species have to overcome the problems of iron insolubility and toxicity. In response to low iron availability in the environment, most fungi excrete ferric iron-specific chelators--siderophores--to mobilize this metal. Siderophore-bound iron is subsequently utilized via the reductive iron assimilatory system or uptake of the siderophore-iron complex. Furthermore, most fungi possess intracellular siderophores as iron storage compounds. Molecular analysis of siderophore biosynthesis was initiated by pioneering studies on the basidiomycete Ustilago maydis, and has progressed recently by characterization of the relevant structural and regulatory genes in the ascomycetes Aspergillus nidulans and Neurospora crassa. In addition, significant advances in the understanding of utilization of siderophore-bound iron have been made recently in the yeasts Saccharomyces cerevisiae and Candida albicans as well as in the filamentous fungus A. nidulans. The present review summarizes molecular details of fungal siderophore biosynthesis and uptake, and the regulatory mechanisms involved in control of the corresponding genes.

Amino Acid Sequence↗
PubMed2003

Interleukin-4 production from human basophils is critically dependent on the storage conditions employed prior to stimulation.

OBJECTIVE AND DESIGN: Marked variations in the interleukin-4 (IL-4)-producing capacity of basophils can be observed when aliquots from the same cell preparation are kept under different conditions before stimulation. The aim of this study was to identify factors affecting the functional activity of basophils and to determine optimal storage conditions. SUBJECTS: Healthy blood donors. METHODS: Aliquots of purified basophils were kept for different time intervals on ice or at 37 degrees C, in buffer or culture medium, respectively. Following subsequent stimulation with anti-IgE, IL-4 release was determined. RESULTS: Upon storage times up to 4 h, basophils produced more IL-4 when kept at 37 degrees C as compared to 4 degrees C. Surprisingly, buffer was superior compared to culture medium for storage. When the storage time was 20 h, IL-4 release was reduced significantly under all conditions studied. CONCLUSION: The storage conditions considerably affect basophil IL-4 release and thus should taken into account when comparing results.

Antibodies, Blocking↗
PubMed2003

[Femoral neck fractures in the elderly -- bipolar hemiarthroplasty in total hip replacement].

INTRODUCTION: In this study surgical risk and functional outcome of bipolar hemiarthroplasty and total hip replacement in elderly patients with femoral neck fractures were compared. METHODS: In a prospective study 54 patients with femoral neck fractures (median age: 80.5 years) were treated by implanting a total hip replacement (group I). Group II comprised 52 patients with 55 femoral neck fractures (median age: 81 years) who underwent bipolar hemiarthroplsty. Pre- and postoperative mobility and social history, perioperative parameters such as duration of surgery, blood loss, and number of transfused blood units as well as postoperative complications and mortality were compared. Function was ascertained by a scoring system. RESULTS: Duration of surgery, blood loss, and numbers of transfused blood units were significantly lower in group II, and mortality rate was lower. Postoperative mobility and medium-term functional score were comparable, whereas in the longer-term follow-up after 8 years group I had a significantly better functional score. CONCLUSION: In elderly patients with femoral neck fracture and high comorbidity, we recommend the implantation of hemiarthroplasty and in healthy, active patients with longer life expectancy the total hip replacement.

Age Factors↗
PubMed2002

An x-ray absorption spectroscopy study of the zinc environment in Langmuir-Blodgett phospholipid multilayers.

For the first time x-ray absorption spectroscopy was used to investigate the Zn environment in Langmuir-Blodgett multilayers. The multilayers were taken as a model of the multilamellar structure of the myelin sheath, the membrane surrounding the nerve axon, which plays a crucial role for signal transduction along the axon. The layers were assembled from the phospholipid dilauroylphosphatidic acid, both in the presence and in the absence of myelin basic protein. The analysis of the extended x-ray absorption fine structure and of the near edge regions of the x-ray absorption spectra at the Zn K-edge provided an accurate description of the local structure showing that the Zn ions are bound to the heads of the phospholipid molecules. The myelin basic protein induces a distortion on the Zn local environment due to a steric constraint but does not substitute the phosphate headgroups. These findings represent an important step in understanding the interplay among myelin basic protein, Zn, and the lipids of the myelin sheath.

Absorptiometry, Photon↗
PubMed2002

[HIV exposure accidents in children. Experience at the emergency admission services of the CHU of Nice].

UNLABELLED: Accidental exposure to human immunodeficiency virus (HIV), either by injury with a discarded syringe or after sexual abuse, increases among the children population. PATIENTS AND METHODS: The entire period of the study was seven-year. Twenty-eight children (14 males, 14 females) underwent three visits after an accidental exposure at Day 0, Day 30th and Day 90th. During each visit, a physical examination, liver enzymes, Ag P24, PCR-RNA HIV, B, C hepatitis serologies were performed. An antiretroviral prophylaxis was proposed when a high risk of HIV transmission was recognized. Anti hepatitis B globulins were administrated when no previous immunization had been made. RESULTS: The median age was 9.3 years (range: 1.5 to 16.7 years). 93% of the children consulted within 48 hours after exposure. Five of them consulted after a sexual aggression with penetration, two after a mucosus exposition and two after deep needle injuries. The source of the contamination was known in five cases. Nine patients were given an antiretroviral treatment for four weeks (seven bitherapy, two tritherapy), with no major side effects. Eighteen and 11 children were seen at the second and third visits, respectively. No case of HIV or HCV infection was observed. CONCLUSION: No case of infection after injury with a discarded syringe was found in our study. This situation differs from what is observed in health care workers, where the higher risk factor is observed. Even if no contamination was found after sexual aggression in our population, the risk of HIV is actual. This is why we propose an antiretroviral prophylaxis against HIV in only one indication, corresponding to sexual penetration.

Adolescent↗