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Biomedical subjects

G Haase

Publications and source records attributed to G Haase.

At least 91 records · Page 5Linked to original sources
PubMed1996

Isolation and characterization of a unique group of slowly growing mycobacteria: description of Mycobacterium lentiflavum sp. nov.

A distinct group of slowly growing mycobacteria was identified on the basis of growth characteristics, biochemical and lipid profiles, and nucleic acid analyses. The isolates showed growth at 22 to 37 degrees C, yellow pigmentation, and negative tests for Tween 80 hydrolysis, nicotinic acid, nitrate reductase, and urease; tests for arylsulfatase, pyrazinamidase, and heat-stable catalase were variable. Analysis of cellular fatty acids by gas-liquid chromatography and mycolic acids by thin-layer chromatography and high-performance liquid chromatography indicated a distinctive pattern which was unlike those of other species. Determination of the 16S rRNA gene sequence showed a unique sequence closely related to Mycobacterium simiae and M. genavense. On the basis of DNA homology studies, we suggest that these organisms are representatives of a novel species, for which the name M. lentiflavum sp. nov. is proposed.

Bacterial Typing Techniques↗
PubMed1996

[Gene therapy of neurological diseases].

In hereditary neurological diseases, gene transfer into neurons is made difficult by: the nature of the cells (postmitotic cells, that cannot be cultured, genetically modified ex vivo, then retransplanted), sometimes, their widespread localization, the blood-brain barrier. However, three viral vectors derived from adenovirus, Herpes simplex virus and adeno-associated virus have been shown to be very efficient in transferring DNA into brain cells. All of these vectors can infect resting cells, especially neurons, and are efficient in vivo. Retroviral vectors which can infect dividing cells only are mainly used for ex vivo genetic modification of cells (neural progenitor cells, myoblasts, fibroblasts) followed by intracerebral transplantation. Alternatively, genetically modified cells can be transplanted in a peripheral site if the transgene product is able to cross the blood-brain barrier or to be transported retrogradely from the nerve terminals. We have especially investigated the potential interest of adenoviral vectors to transfer foreign genes into brain cells and to treat animal models of neurological diseases. These vectors allowed us to transfer the lacZ gene into any neural cell type, including neurons, glia, photoreceptors and olfactory receptors, ex vivo, in cell culture, and in vivo, by stereotactic administration. In addition, axonal transport of adenoviral vectors has been demonstrated, e.g. in the substantia nigra after injection into the striatum, in the olfactory bulb after intranasal instillation and in spinal motor neurons after intramuscular injection. After intracerebroventricular injection, ependymal cells are massively infected and express the transgene for several months, as this is also observed in neurons. Through the spinal canal and cerebrospinal fluid, the vector can diffuse to a considerable distance from the injection point, e.g. to the lumbar spinal cord after injection in the suboccipital region. To test the biological function of transgenes transferred through adenoviral vectors, we have constructed vectors with cDNAs or genes for various neutrophic factors: CNTF, NT3, BDNF and GDNF. These vectors were biologically active on target cells, ex vivo and in vivo. In the pmn mouse model of progressive motor neuronal degeneration, some of these vectors, alone or combined, allowed for prolongation of life of homozygous animals by more than two fold, and for decrease in the demyelination of phrenic nerve axons. Finally, we have also constructed an adenoviral vector carrying the alpha-hexosaminidase cDNA, encoding the enzyme subunit deficient in Tay Sachs patients. This vector permitted to normalize ganglioside metabolism in Tay Sachs fibroblasts and is currently tested in knock out mice deficient in hexosaminidase A. In spite of all these encouraging results, we are nevertheless aware that progress in vector design and delivery strategies will be needed before gene therapy can become a realistic therapeutical strategy in humans.

Adenoviridae↗
PubMed1995

Measuring resistance to phagocytosis of group A and G streptococci: comparison of direct bactericidal assay and flow cytometry.

M protein is thought to contribute to the ability of non-opsonized group A and group G streptococci (GAS and GGS, respectively) to resist phagocytosis by polymorphonuclear leukocytes. In previous studies, correlation between M protein expression and phagocytosis was determined by incubating these pathogens in human blood and comparing colony-forming bacterial counts prior to and after exposure to blood (direct bactericidal assay; DBA). Here, we report the application of flow cytometry to measure GAS and GGS resistance to phagocytosis. The results of the assays were in complete agreement with those from DBAs. Nevertheless, flow cytometry was regarded as superior to DBA because of its speed and potential uses for quantitative studies. In addition, the use of anti-CD11b monoclonal antibody for granulocyte staining guaranteed a non-compromized granulocyte function. The optimized protocol for flow cytometry presented here could be utilized to directly measure the involvement of individual protein types in bacterial resistance to phagocytosis.

Blood Bactericidal Activity↗
PubMed1995

Phylogenetic analysis of ten black yeast species using nuclear small subunit rRNA gene sequences.

The nuclear small subunit rRNA genes of authentic strains of the black yeasts Exophiala dermatitidis, Wangiella dermatitidis, Sarcinomyces phaemuriformis, Capronia mansonii, Nadsoniella nigra var. hesuelica, Phaeoannellomyces elegans, Phaeococcomyces exophialae, Exophiala jeanselmei var. jeanselmei and E. castellanii were amplified by PCR and directly sequenced. A putative secondary structure of the nuclear small subunit rRNA of Exophiala dermatitidis was predicted from the sequence data. Alignment with corresponding sequences from Neurospora crassa and Aureobasidium pullulans was performed and a phylogenetic tree was constructed using the neighbor-joining method. The obtained topology of the tree was confirmed by bootstrap analysis. Based upon this analysis all fungi studied formed a well-supported monophyletic group clustering as a sister group to one group of the Plectomycetes (Trichocomaceae and Onygenales). The analysis confirmed the close relationship postulated between Exophiala dermatitidis, Wangiella dermatitidis and Sarcinomyces phaeomuriformis. This monophyletic clade also contains the telemorph species Capronia mansonii thus confirming the concept of a teleomorph connection of the genus Exophiala to a member of the herpotrichiellaceae. However, Exophiala castellanii did not belong to this clade. Therefore, this species is not the anamorph of Capronia mansonii as it was postulated.

Ascomycota↗
PubMed1995

Recurrent bacteremia due to Brevibacterium casei in an immunocompromised patient.

A case of an immunocompromised patient who experienced two episodes of septicemia caused by a coryneform bacterium is reported. Biochemical characteristics and analysis of cellular fatty acids and of cell wall components showed two identical strains of Brevibacterium casei to be responsible for these infections. The lack of easy-to-perform methods for identification may have led, in the past, to an underestimation of the role of this bacterium, especially in immunocompromised patients.

Adult↗
PubMed1995

[Unilateral recurrent nerve paralysis in suspected Lyme borreliosis].

Cranial nerve palsy can often be observed in Borrelia burgdorferi infection. A dysphonic patient with a long lasting left-sided recurrent nerve palsy was treated with ceftriaxone, an antibiotic drug for the therapy of Lyme borreliosis. On the 7th day of application the paretic vocal fold showed recovering movements up to regular vocal fold function and normal stroboscopic results. Clinical and serologic constellations and their therapeutical implications are discussed.

Adult↗
PubMed1994

A prospective randomized trial of delayed versus immediate repair of congenital diaphragmatic hernia.

From March 1990 to January 1993, a randomized prospective study was performed to determine the optimal timing of surgery for infants with high-risk congenital diaphragmatic hernia (CDH). Thirty-two CDH patients who presented with respiratory distress within 12 hours after birth were randomly divided into two groups: Group A had early repair (within 6 hours), and group B had delayed repair (at 96+ hours). Extracorporeal membrane oxygenation (ECMO) was initiated in both groups as necessary. Fourteen patients were assigned to group A, and 18 were assigned to group B. Two patients initially assigned to group A had acute deterioration, and their operations had to be postponed. Data were collected, but these patients were eliminated from the study. The two groups were comparable based on gestational age, birth weight, Bohn's criteria, and oxygenation and ventilatory index. Nine of 12 group A patients (75%) survived, and 13 of 18 group B patients (72%) survived (P > .05, not significant). The ECMO requirements for the two groups were not significantly different (8 of 12 (67%) v 16 of 18 (89%); P > .05). Surgical intervention for bleeding complications related to ECMO was required in three of eight (38%) with immediate repair and seven of 16 (44%) with delayed repair (P > .05). There was no difference in survival nor incidence of ECMO between the two groups. This is the first prospective study of timing of hernia repair that supports the conclusions of earlier reports of retrospective studies.

Extracorporeal Membrane Oxygenation↗
PubMed1994

[Anticardiolipin antibodies in vascular occlusions of the eye].

Elevated levels of anticardiolipin antibodies (ACA) have recently been found to be associated with occlusive diseases such as myocardial or cerebral infarction or venous thrombosis. In a prospective study anticardiolipin antibodies (both IgG and IgM) were measured by ELISA in 140 patients with acute vascular occlusions of the eye. Patients with clinical evidence for lupus erythematodes, HIV infection or elevated concentrations of antinuclear antibodies (IIFT with HEp-2 as antigen, LD Diagnostika, Heiden, FRG) were excluded. Elevated concentrations of IgG-ACA and IgM-ACA were found in 9% of the cases, with no correlation with the type of ocular vascular occlusion (retinal artery occlusion, retinal vein occlusion, anterior ischemic optic neuropathy). These results indicate that the anticardiolipin syndrome with elevated concentration of anticardiolipin antibodies may also have a causal role in some patients with occlusive eye diseases, whereas in most patients the concentrations were within normal ranges.

Adult↗
PubMed1993

Nutritional physiology and selective isolation of Exophiala dermatitidis.

The nutritional physiology of ten strains of Exophiala dermatitidis was investigated. The growth reactions to lactose, citrate, nitrate, nitrite, lysine, creatine and creatinine differ from those found in closely related black yeasts. In addition, it is the only Exophiala species which is able to grow at 40 degrees C. A selective medium containing meso-erythritol as sole carbon source was evaluated. This medium is particularly useful for the isolation of black yeasts from lungs of patients with cystic fibrosis as well as from the environment.

Culture Media↗
PubMed1993

Protection of intestinal anastomoses by biodegradable intraluminal bypass tubes under the condition of general peritonitis: an experimental study on the CLP model in rats.

The purpose of this experimental study was to affirm the protective effect of biodegradable tubes for the intraluminal bypass procedure under the adverse condition of general peritonitis. General peritonitis was induced by means of the cecal ligation and puncture (CLP) model in the rat. The leakage rate in the control group (n = 20) without anastomotic protection was 70 percent (14/20). In three therapeutic groups, each consisting of 20 animals, the intestinal anastomoses were protected by an intraluminal bypass tube of different biodegradable biomaterials (collagen-II, BCL-002, and BCL-004). The best results were noted in the collagen-II and BCL-002 groups, where the leakage rates could be reduced to 10 percent. These highly significant results (P = 0.0001) prove the feasibility of biodegradable biomaterials for the intraluminal bypass procedure in the rat, even in cases with underlying peritonitis.

Anastomosis, Surgical↗
PubMed1993

Diagnosis and treatment of a solitary infected hepatic cyst in two patients with adult polycystic kidney disease.

We report on two women (one 52-year-old who underwent kidney transplantation 15 months ago and the other, 71-year-old, undergoing hemodialysis) both with adult polycystic kidney disease who had to be hospitalized because of recurrent fever attacks up to 40 degrees C without any remarkable abdominal symptoms. Staphylococcus hominis and E. coli were recovered respectively from blood cultures of both patients. Evidence for the presence of a solitary infected cyst in the liver could only be obtained by computed tomography (CT) with i.v. administration of a contrast medium. In both cases the infected liver cyst was non-operatively drained with a CT-guided percutaneous catheter and therefore the necessity of laparotomy was avoided.

Aged↗
PubMed1993

Prevalence of Helicobacter pylori in patients with chronic renal failure.

The prevalence of Helicobacter pylori (H. pylori) was investigated in 164 consecutive patients with different degrees of renal function; group I (normal renal function) n = 84, group II (chronic renal failure, CLCR > or = 5 < 90 ml/min) n = 45, group III (haemodialysis therapy) n = 35, to test the hypothesis that the resulting different concentrations of urea in the gastric juice would have an influence on the colonization of the gastric mucosa by these urea-splitting bacteria. As every individual method for the detection of H. pylori shows disadvantages, the results of the detection methods used (urease test, Warthin-Starry stain, bacterial cultivation, direct examination of the processed sample by phase-contrast microscopy) were combined in a cumulative evaluation. These calculated cumulative indices for the antrum and corpus showed no statistically significant differences between the studied groups. The prevalence of H. pylori ranged from 34 to 54%. The histopathological findings were similar in all groups. In spite of the fact that patients with renal dysfunction had significantly higher levels of serum gastrin (P < 0.05), there was no influence on the gastric juice pH value. The relationship between the cumulative index and ammonia concentration in gastric juice was found to be linear (P < 0.05). The higher urea levels in the blood and gastric juice of patients with renal failure do not seem to be a risk factor for infection with H. pylori.

Ammonia↗
PubMed1992

Exophiala dermatitidis pneumonia in cystic fibrosis.

The chest X-ray film of a girl with cystic fibrosis (CF) showed slowly increasing mottled densities during the 6th and 7th year of her life. Pulmonary symptoms and distress proceeded fast in spite of intensive treatment with antibiotics, corticosteroids, and physiotherapy. Three different fungal organisms were repeatedly cultured from the sputum: Candida albicans, Aspergillus fumigatus, and Exophiala dermatitidis. Antibodies against C. albicans were in the normal range. Candida antigen in blood and antibodies against A. fumigatus were absent. Antibodies against E. dermatitidis were detected by a recently developed indirect immunofluorescence assay. It seems most probable that E. dermatitidis was the causal agent for fungal pneumonia in this case. Under therapy with amphotericin B and flucytosine the clinical course and radiological appearance improved but definitive eradication of E. dermatitidis was only achieved after treatment with itraconazole. The isolation of this fungus from the sputum of a CF patient is reported for the first time. The significance of fungal infections in CF is discussed.

Child↗